研究者総覧

渡辺 幸三 (ワタナベ コウゾウ)

  • 沿岸環境科学研究センター 教授
メールアドレス: watanabe.kozo.mjehime-u.ac.jp
Last Updated :2021/01/16

研究者情報

学位

  • 博士(工学)(2005年03月 東北大学)

論文上での記載著者名

  • Kozo Watanabe

ホームページURL

科研費研究者番号

  • 80634435

ORCID ID

J-Global ID

プロフィール

  • 【分子生態学】  次世代DNAシーケンシング等を活用した正確・迅速・安価な流域生物多様性評価(例,河川底生動物,細菌,魚類)



    【生態疫学】 東南アジアの蚊媒介感染症制御を目的とした生態疫学研究(例,フィリピン・インドネシアのデング熱媒介蚊の調査)



    【生物多様性と進化】 適応進化(自然選択)の観点から遺伝子・種レベルの生物多様性の環境影響評価(例,温暖化影響予測)



    【国際共同研究】 フィリピン,インドネシア,スイス,アメリカ,ドイツ,日本などの幅広い研究フィールド.活発な国際共同研究.



    キーワード: 分子生態学,河川生態系,デング熱,熱帯感染症,次世代シークエンシング,機械学習

研究キーワード

  • 集団遺伝学   進化生物学   系統発生   底生動物   河川生態学   分子生態学   デング熱   熱帯感染症   次世代シークエンサー   土木環境システム   生物多様性   分類学   ノロウイルス   

研究分野

  • 社会基盤(土木・建築・防災) / 土木環境システム
  • 環境・農学 / 自然共生システム

経歴

  • 2020年04月 - 現在  愛媛大学沿岸環境科学研究センター (CMES)教授
  • 2019年11月 - 現在  愛媛大学海外サテライトオフィス・フィリピン(デ・ラサール大学)室長
  • 2019年04月 - 現在  愛媛大学東南アジア環境健康研究ユニットユニット長
  • 2019年04月 - 現在  愛媛大学住友電工社会貢献基金寄付講座「東南アジアの蚊媒介感染症講座」教授(兼任)
  • 2018年04月 - 現在  山形大学農学部客員教授
  • 2017年04月 - 現在  De La Salle University, Philippines,Biological Control Research Unit (BCRU)客員教授
  • 2017年04月 - 2020年03月  愛媛大学沿岸環境科学研究センター教授(兼任)
  • 2017年04月 - 2020年03月  愛媛大学大学院理工学研究科教授
  • 2017年08月 - 2017年10月  Berlin Center for Genomics in Biodiversity Research, Germany客員教授
  • 2015年10月 - 2017年03月  De La Salle University, Philippines,Biology Department,Visiting Scholar
  • 2015年04月 - 2017年03月  愛媛大学沿岸環境科学研究センター准教授(兼任)
  • 2012年04月 - 2017年03月  愛媛大学大学院理工学研究科准教授
  • 2010年04月 - 2012年03月  Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB),ドイツEU Marie-Curie Research Fellow
  • 2009年04月 - 2010年03月  Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB),ドイツ日本学術振興会海外特別研究員
  • 2006年04月 - 2009年03月  東北大学工学研究科日本学術振興会特別研究員(PD)
  • 2005年04月 - 2006年03月  東北大学工学研究科研究支援者/教務補佐員
  • 2002年04月 - 2005年03月  東北大学工学研究科日本学術振興会特別研究員(DC1)

学歴

  • 2002年04月 - 2005年03月   東北大学   工学研究科   土木工学専攻 博士後期課程
  • 2000年04月 - 2002年03月   東北大学   工学研究科   土木工学専攻 博士前期課程
  • 1996年04月 - 2000年03月   東北大学   工学部   土木工学科

研究活動情報

論文

  • Billy Joel M. Almarinez, Mary Jane A. Fadri, Richard Lasina, Mary Angelique A. Tavera, Thaddeus M. Carvajal, Kozo Watanabe, Jesusa C. Legaspi, Divina M. Amalin
    Insects 12 1 26  2021年01月 [査読有り]
     研究論文(学術雑誌) 
    Comperiella calauanica is a host-specific endoparasitoid and effective biological control agent of the diaspidid Aspidiotus rigidus, whose outbreak from 2010 to 2015 severely threatened the coconut industry in the Philippines. Using the maximum entropy (Maxent) algorithm, we developed a species distribution model (SDM) for C. calauanica based on 19 bioclimatic variables, using occurrence data obtained mostly from field surveys conducted in A. rigidus-infested areas in Luzon Island from 2014 to 2016. The calculated the area under the ROC curve (AUC) values for the model were very high (0.966, standard deviation = 0.005), indicating the model’s high predictive power. Precipitation seasonality was found to have the highest relative contribution to model development. Response curves produced by Maxent suggested the positive influence of mean temperature of the driest quarter, and negative influence of precipitation of the driest and coldest quarters on habitat suitability. Given that C. calauanica has been found to always occur with A. rigidus in Luzon Island due to high host-specificity, the SDM for the parasitoid may also be considered and used as a predictive model for its host. This was confirmed through field surveys conducted between late 2016 and early 2018, which found and confirmed the occurrence of A. rigidus in three areas predicted by the SDM to have moderate to high habitat suitability or probability of occurrence of C. calauanica: Zamboanga City in Mindanao; Isabela City in Basilan Island; and Tablas Island in Romblon. This validation in the field demonstrated the utility of the bioclimate-based SDM for C. calauanica in predicting habitat suitability or probability of occurrence of A. rigidus in the Philippines.
  • Regilme, M. A. F, T. M. Carvajal, A. C. Honnen, D. M. Amalin, K. Watanabe
    PLOS Neglected Tropical Diseases , accepted 2021年 [査読有り]
     研究論文(学術雑誌) 
    AbstractDengue is endemic in tropical and subtropical countries and is transmitted mainly by Aedes aegypti. Mosquito movement can be affected by human-made structures such as roads that can act as a barrier. Roads can influence the population genetic structure of Ae. aegypti. We investigated the genetic structure and gene flow of Ae. aegypti as influenced by a primary road, España Boulevard (EB) with 2000-meter-long stretch and 24-meters-wide in a very fine spatial scale. We hypothesized that Ae. aegypti populations separated by EB will be different due to the limited gene flow as caused by the barrier effect of the road. A total of 376 adults and larval Ae. aegypti were collected from June to September 2017 in 21 sites across EB. North (N1-N11) and South (S1-S10) comprised of 211 and 165 individuals, respectively. All mosquitoes were genotyped at 11 microsatellite loci. AMOVA FST indicated significant genetic differentiation across the road. The constructed UPGMA dendrogram found 4 genetic groups revealing the clear separation between North and South sites across the road. On the other hand, Bayesian cluster analysis showed four genetic clusters (K = 4) wherein each individual samples have no distinct genetic cluster thus genetic admixture. Moreover, significant positive spatial autocorrelation was observed at 100 - 200 m distance class, suggesting dispersal potential of the adult mosquitoes within a 200 m spatial scale. Our results suggest that human-made landscape features such as primary roads are potential barriers to mosquito movement thereby limiting its gene flow across the road. This information is valuable in designing an effective mosquito control program in a very fine spatial scale. Author SummaryDengue, a mosquito-borne viral infection is a serious health problem in tropical and subtropical countries such as Philippines. Most dengue prevention programs aim to eradicate its mosquito vector, Aedes aegypti. A successful population control program is reliant in understanding the mosquito behavior and ecology including how human-made structures such as roads influence its expansion and movement. Previous studies have discovered the barrier effect of roads in the movement of mosquitoes. In this study, we examined the influence of roads in the population genetic structure of Ae. aegypti in a fine spatial scale using 11 microsatellite markers. We found significant genetic differentiation of mosquito populations across the road. Our results suggest limited gene flow across the road and supports our hypothesis that roads are potential barriers to mosquito dispersal. This information can be used in designing an effective mosquito population control zones in perceived barrier to mosquito dispersal such as roads.
  • Underdiagnosis does not account for the decrease in dengue cases in Bandung, Indonesia
    Faridah, L, S. Ekawardhani, H. L. Wiraswati, N. Fauziah, F. R. Rinawan, W. Mayasarid, K. Watanabe
    Systematic Reviews in Pharmacy , accepted 2021年 [査読有り]
     研究論文(学術雑誌)
  • Spotted fever group Rickettsiae (SFGR) found in a follow-up investigation of in ticks after the occurrence of Japanese spotted fever human case in Niigata Prefecture, Japan
    Arai, R, M. Hayashi, M. Kato, J. Aoki, A. Nishida, K. Watanabe, C. Hirokawa, S. Ikeda, T. Tamura, K Watanabe, M. A. F. Regilme, M. O. Sato, M. Sato
    Scientific Reports , accepted 2021年 [査読有り]
  • Thaddeus M. Carvajal, Divina M. Amalin, Kozo Watanabe
    Infection, Genetics and Evolution 87 104676  2021年01月 [査読有り]
     研究論文(学術雑誌)
  • Levente-Péter Kolcsár, Daichi Kato, Maribet Gamboa, Kozo Watanabe
    ZooKeys 1000 71 - 105 2020年12月 [査読有り]
     研究論文(学術雑誌) 
    Japanese species of the genus Nipponomyia Alexander, 1924 are revised. Two new species, Nipponomyia okinawensis Kolcsár & Kato, sp. nov. and N. yakushimensis Kolcsár & Kato, sp. nov. are described from the Ryukyu Islands. Images of habitus and wings, illustrations of male and female terminalia, and distribution maps are provided for the Japanese species. A key to the world species of Nipponomyia is added. DNA barcodes of three Japanese Nipponomyia are provided, representing the first barcodes from the genus.
  • Ming‐Chih Chiu, Bin Li, Kei Nukazawa, Vincent H. Resh, Thaddeus Carvajal, Kozo Watanabe
    Diversity and Distributions 26 12 1813 - 1824 2020年12月 [査読有り]
     研究論文(学術雑誌)
  • Ming‐Chih Chiu, Kei Nukazawa, Thaddeus Carvajal, Vincent H. Resh, Bin Li, Kozo Watanabe
    Ecography 43 12 1891 - 1901 2020年12月 [査読有り]
     研究論文(学術雑誌)
  • Daichi Kato, Kozo Watanabe, Levente-Péter Kolcsár
    ZooKeys 999 147 - 163 2020年11月 [査読有り]
     研究論文(学術雑誌) 
    Japanese species of the genus Ulomorpha Osten Sacken, 1869 are revised and U. amamiana Kato & Kolcsár, sp. nov. and U. longipenis Kato & Kolcsár, sp. nov. are described. A key to the four Japanese species of the genus is provided, with images of habitus and wings, and drawings of their male terminalia. Ulomorpha amamiana Kato & Kolcsár, sp. nov. is the first representative of the genus discovered from the Oriental region.
  • Jean Claude Balingit, Thaddeus M. Carvajal, Mariko Saito-Obata, Maribet Gamboa, Amalea Dulcene Nicolasora, Ava Kristy Sy, Hitoshi Oshitani, Kozo Watanabe
    Parasites & Vectors 13 1 594  2020年11月 [査読有り]
     研究論文(学術雑誌) 
    Abstract Background Vector control measures are critical for the prevention and reduction of dengue virus (DENV) transmission. Effective vector control is reliant not only on knowledge of mosquito abundance, but also on the timely and accurate detection of mosquito-borne infection. Mosquito-based virus surveillance programs typically rely on pool-based mosquito testing, although whether individual-based mosquito testing is a feasible alternative to this has not been widely studied. Applying an individual-based mosquito testing approach, we conducted a 1-month surveillance study of DENV in adult Aedes aegypti mosquitoes in homes of suspected dengue patients during the 2015 peak dengue season in Tarlac City, Philippines to more accurately assess the mosquito infection rate and identify the DENV serotypes and genotypes concurrently co-circulating in mosquitoes and patients there. Methods We performed a one-step multiplex real-time reverse transcription-polymerase chain reaction (RT-PCR) assay for the simultaneous detection and serotyping of DENV in patients and individual female Ae. aegypti mosquitoes. Additionally, we performed sequencing and phylogenetic analyses to further characterize the detected DENV serotypes in mosquitoes and patients at the genotype level. Results We collected a total of 583 adult Ae. aegypti mosquitoes, of which we individually tested 359 female mosquitoes for the presence of DENV. Ten (2.8%) of the 359 female mosquitoes were positive for the presence of DENV. We detected DENV-1, DENV-2, and DENV-4 in the field-collected mosquitoes, which was consistent with the serotypes concurrently found in infected patients. Sequencing and phylogenetic analyses of the detected DENV serotypes based on the partial sequence of the evelope (E) gene revealed three genotypes concurrently present in the sampled mosquitoes and patients during the study period, namely DENV-1 genotype IV, DENV-2 Cosmopolitan genotype, and DENV-4 genotype II. Conclusions We demonstrated the utility of a one-step multiplex real-time RT-PCR assay for the individual-based DENV surveillance of mosquitoes. Our findings reinforce the importance of detecting and monitoring virus activity in local mosquito populations, which are critical for dengue prevention and control.
  • Billy Joel M. Almarinez, Alberto T. Barrion, Mario V. Navasero, Marcela M. Navasero, Bonifacio F. Cayabyab, Jose Santos, R. Carandang, Jesusa C. Legaspi, Kozo Watanabe, Divina M. Amalin
    Insects 11 11 745 - 745 2020年10月 [査読有り]
     研究論文(学術雑誌) 
    The coconut scale insect, Aspidiotus rigidus Reyne, caused a major pest outbreak in coconut plantations and stands in the Southern Tagalog region of Luzon Island in the Philippines between 2010 and 2015. To determine if parasitism by Comperiella calauanica Barrion, Almarinez and Amalin, a native encyrtid, could have been a factor in the eventual management of the outbreak by 2015, we estimated and assessed its parasitization levels on A. rigidus colonies on field-collected samples from selected points in three provinces in the Southern Tagalog Region across three sampling periods. We observed that C. calauanica consistently occurred only in areas where A. rigidus populations occurred, with high parasitization levels in the Southern Tagalog sites from 2014 to 2015. Results of correlation and regression of total scale count against parasitized scale count suggest putative host density-dependent parasitism by C. calauanica in the field. A marked decrease in the abundance of A. rigidus was recorded concurrently with visually observable recovery of coconut trees from the third quarter of 2014 up to the second quarter of 2016. Similar results of significant reduction in A. rigidus populations concurrent with high percent parasitization by mass-reared and released C. calauanica were found in the Zamboanga Peninsula from 2018 to 2020. Our findings and observations altogether suggest that host-specific parasitization by C. calauanica effected biological control, which may have contributed to the eventual management of the A. rigidus outbreak in the Southern Tagalog Region, and also in the Zamboanga Peninsula where similar recovery of coconut trees were observed within a year after inoculative releases of C. calauanica.
  • Joeselle M Serrana, Kozo Watanabe
    bioRxiv 2020年10月 研究論文(学術雑誌) 
    Sequential membrane filtration as a pre-processing step for the isolation of microorganisms could provide good quality and integrity DNA that can be preserved and kept at ambient temperatures before community profiling through culture-independent molecular techniques, e.g., 16s rDNA amplicon sequencing. Here, we assessed the impact of pre-processing sediment samples by sequential membrane filtration (from 10, 5 to 0.22 μm pore size membrane filters) for 16s rDNA-based community profiling of sediment-associated microorganisms. Specifically, we examined if there would be method-driven differences between non- and pre-processed sediment samples regarding the quality and quantity of extracted DNA, PCR amplicon, resulting high-throughput sequencing reads, microbial diversity, and community composition. We found no significant difference in the quality and quantity of extracted DNA and PCR amplicons between the two methods. Although we found a significant difference in raw and quality-filtered reads, read abundance after bioinformatics processing (i.e., denoising and the chimeric-read filtering steps) were not significantly different. These results suggest that read abundance after these read processing steps were not influenced by sediment processing or lack thereof. Although the non- and pre-processed sediment samples had more unique than shared amplicon sequence variants (ASVs), we report that their shared ASVs accounted for 74% of both methods' absolute read abundance. More so at the genus level, the final collection filter identified most of the genera (95% of the reads) captured from the non-processed samples, with a total of 51 false-negative (2%) and 59 false-positive genera (3%). Accordingly, the diversity estimates and community composition were not significantly different between the non- and pre-processed samples. We demonstrate that while there were differences in shared and unique taxa, both methods revealed comparable microbial diversity and community composition. We also suggest the inclusion of sequential filters (i.e., pre- and mid-filters) in the community profiling, given the additional taxa not detected from the non-processed and the final collection filter. Our observations highlight the feasibility of pre-processing sediment samples for community analysis and the need to further assess sampling strategies to help conceptualize appropriate study designs for sediment-associated microbial community profiling.
  • Rachel L. Malison, Bonnie K. Ellis, Amanda G. DelVecchia, Hailey Jacobson, Brian K. Hand, Gordon Luikart, H. Arthur Woods, Maribet Gamboa, Kozo Watanabe, Jack A. Stanford
    The Bulletin of the Ecological Society of America 101 4 e01767  2020年10月 研究論文(学術雑誌)
  • Sakiko Yaegashi, Tatsuo Omura, Kozo Watanabe
    AoB PLANTS 12 5 plaa043  2020年10月 [査読有り]
     研究論文(学術雑誌) 
    The black locust Robinia pseudoacacia (Robinieae, Fabaceae) is a common invasive riparian tree in Japan. There are less effective management strategies to remove the tree from the riparian area because of its quickly established high population. We investigated the expansion patterns of R. pseudoacacia through sympatric (i.e. between high- and low-water channel (HWC/LWC) within a study site) and allopatric (i.e. along river corridor) dispersal in the Tama River (Tokyo, Japan). Four microsatellites were used to examine the effects of gene flow on six populations in three sites. These subpopulations showed small genetic distance (i.e. no barrier or slightly limited) and genetically mixed population structure. It indicated that both sympatric and allopatric dispersals were active. Many migrants were younger individuals (i.e. <5 years old) and were found in the LWC area. Thus, the LWC could receive more migrants than the HWC through both types of dispersals. In addition, our age and genetic structure analyses reveal that recruited individuals likely settled immediately after the clearing project of R. pseudoacacia through sympatric dispersal. It appears that the migration by allopatric dispersal occurred following this. For the effective management of R. pseudoacacia, migrants should be removed regularly following initial removal of invaders during site restoration.
  • Rachel L. Malison, Bonnie K. Ellis, Amanda G. DelVecchia, Hailey Jacobson, Brian K. Hand, Gordon Luikart, H. Arthur Woods, Maribet Gamboa, Kozo Watanabe, Jack A. Stanford
    Ecology 101 10 e03127  2020年10月 [査読有り]
     研究論文(学術雑誌)
  • Maribet Gamboa, Yusuke Gotoh, Arnelyn D Doloiras-Larano, Kozo Watanabe
    bioRxiv 2020年09月 研究論文(学術雑誌) 
    Latitudinal variation has been known to create strong selection pressure for genomic variation that enables the adaptation and survival of organisms. By altering gene expression patterns, organisms can modify their adaptive potential to heterogeneous environmental conditions along a latitudinal gradient; however, there is a gap in our understanding of how physiological consequences in wild species are affected and how changing environmental conditions act on multiple species. Here, we investigated how seven stream stonefly species sampled from four geographical regions in Japan differ in their responses to latitudinal variations by measuring gene expression (RNA-sequencing) differences within species and gene co-expression among species. We found that a large number of genes (622) were differentially expressed along the latitudinal gradient. The high species-specific gene expression diversity found at higher latitude regions was probably associated with low temperatures and high water discharge, which suggests the adaptive potential of stonefly specie. In contrast, similar gene expression patterns among species was observed at lower latitudes, which suggests that strong environmental stress occurs in warmer regions. Weighted gene co-expression network analysis (WGCNA) identified 22 genes with similar expression patterns among species along the latitudinal gradient. Among the four geographical regions, high differential expression patterns in the co-expressed genes from two regions were found, suggesting that the local environment strongly affects gene expression patterns among species in these regions. Respiration, metabolism, and developmental co-expressed genes exhibited a latitudinal cline, showing clear evidence of divergent adaptive responses to latitude. Our findings demonstrate that stonefly species are differentially adapted to local environmental conditions, and imply that adaptation in gene expression could be shared by multiple species under environmental stress conditions. This study highlights the importance of considering multiple species when evaluating the consequences of environmental changes on aquatic insect communities, and possible mechanisms to cope with environmental changes.
  • Francisco, M. E, T. M. Carvajal, M. Ryo, K. Nukazawa, D. M. Amalin, K. Watanabe
    bioRxiv 2020年09月 研究論文(学術雑誌) 
    ABSTRACTBackgroundDengue is an endemic vector-borne disease influenced by environmental factors such as landscape and climate. Previous studies separately assessed the effects of landscape and climate factors on mosquito occurrence and dengue incidence. However, both factors interact in time and space to affect mosquito development and dengue disease transmission. For example, eggs laid in a suitable environment can hatch after being submerged in rain or flood water. ObjectivesThis study aimed to investigate the combined influences of landscape and climate factors on mosquito occurrence and dengue incidence. MethodsEntomological, epidemiological, and landscape data from the rainy season (July-December) were obtained from respective government agencies in Metro Manila, Philippines, from 2012 to 2014. Temperature, precipitation, and vegetation data were obtained through remote sensing. A random forest algorithm was used to select the landscape and climate variables. Afterwards, using the identified key variables, a model-based (MOB) recursive partitioning was implemented to test the combinatory influences of landscape and climate factors on the ovitrap index and dengue incidence. ResultsThe MOB recursive partitioning for the ovitrap index indicated that mosquito occurrence was higher in high residential density areas, where industrial areas also exist and are well connected with roads. Precipitation was another key covariate modulating the effects of landscape factors, possibly by expanding breeding sites and activating mosquito reproduction. Moreover, the MOB recursive partitioning indicated that precipitation was the main predictor of dengue incidence, with a stronger effect in high residential density and commercial areas. DiscussionPrecipitation with floods has epidemiologically important implications by damaging shelters and causing population displacement, thus increasing exposure to dengue vectors. Our findings suggest that the intensification of vector control during the rainy season can be prioritized in residential and commercial areas to better control dengue disease dynamics.
  • Somar Israel D. Fernando, Khristina G. Judan Cruz, Kozo Watanabe
    BioNanoScience 10 3 696 - 704 2020年09月 [査読有り]
     研究論文(学術雑誌) 
    © 2020, Springer Science+Business Media, LLC, part of Springer Nature. The inevitable occurrence of diseases caused by bacterial pathogens is one of the main constraints in tilapia industry that has resulted in major economic losses. The study reveals the advantages of quorum sensing inhibition through nanotechnology in developing antivirulence drugs to control aquaculture pathogens using scientifically untapped medicinal plants, the ethnobotanicals. The ethnobotanical crude extracts (CEs) and biologically synthesized gold nanoparticles (CEs + AuNPs) of the Ilongot-Eǵongot community exhibit quorum sensing inhibition (QSI) activity through inhibition of the biofilm formation against gram-positive Streptococcus agalactiae. Furthermore, ethnobotanical CEs + AuNPs show much greater activity than its counterpart CEs in antibacterial and biofilm formation assay in S. agalactiae which is molecularly confirmed by gene expression analysis. The results indicate the potential of these ethnobotanicals for therapeutic approach in which it showed minimal expression of agrA gene linked in biofilm formation and connotes maximal inhibition of QS in S. agalactiae thereby can possibly inhibit bacterial resistance and virulence.
  • Bin Li, Sakiko Yaegashi, Thaddeus M. Carvajal, Maribet Gamboa, Ming Chih Chiu, Zongming Ren, Kozo Watanabe
    Ecology and Evolution 10 13 6677 - 6687 2020年07月 [査読有り]
     研究論文(学術雑誌) 
    © 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. Adaptive divergence is a key mechanism shaping the genetic variation of natural populations. A central question linking ecology with evolutionary biology is how spatial environmental heterogeneity can lead to adaptive divergence among local populations within a species. In this study, using a genome scan approach to detect candidate loci under selection, we examined adaptive divergence of the stream mayfly Ephemera strigata in the Natori River Basin in northeastern Japan. We applied a new machine-learning method (i.e., random forest) besides traditional distance-based redundancy analysis (dbRDA) to examine relationships between environmental factors and adaptive divergence at non-neutral loci. Spatial autocorrelation analysis based on neutral loci was employed to examine the dispersal ability of this species. We conclude the following: (a) E. strigata show altitudinal adaptive divergence among the populations in the Natori River Basin; (b) random forest showed higher resolution for detecting adaptive divergence than traditional statistical analysis; and (c) separating all markers into neutral and non-neutral loci could provide full insight into parameters such as genetic diversity, local adaptation, and dispersal ability.
  • Thaddeus M. Carvajal, Kohei Ogishi, Sakiko Yaegeshi, Lara Fides T. Hernandez, Katherine M. Viacrusis, Howell T. Ho, Divina M. Amalin, Kozo Watanabe
    PLOS Neglected Tropical Diseases 14 5 e0008279 - e0008279 2020年05月 [査読有り]
     研究論文(学術雑誌)
  • RaoRao Mo, Maribet Gamboa, Kozo Watanabe, GuoQuan Wang, WeiHai Li, Ding Yang, Dávid Murányi
    PLOS ONE 15 3 e0229120 - e0229120 2020年03月 [査読有り]
     研究論文(学術雑誌)
  • Lia Faridah, Fedri Ruluwedrata Rinawan, Nisa Fauziah, Wulan Mayasari, Angga Dwiartama, Kozo Watanabe
    International Journal of Environmental Research and Public Health 17 5 2020年03月 [査読有り]
     研究論文(学術雑誌) 
    © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This study was performed to evaluate the health information system regarding the dengue surveillance system in Indonesia. Major obstacles to the implementation of an effective health information system regarding dengue cases in Bandung are examined, and practical suggestions on measures to overcome them are discussed. The study utilized a mixed-method research design using qualitative approaches: document analysis, key informants and focus group interviews. Thirty key informants were selected, comprised of policymakers, senior managers, and staff at the Ministry of Health. Data from documents and transcripts were evaluated through a modified Institutional Analysis and Development (IAD) framework described by Ostrom. Through this study, we have identified several issues that hinder the effective implementation of the health information system in the case of dengue in Bandung. In the end, we propose several recommendations for reform that encompasses motivational, strategic, and structural approaches to each component of the analysis. Through evaluation of the health information system for dengue surveillance in Indonesia, we conclude that well-coordination in multi-level governance in a country as large as Indonesia is the key in the implementation of the health information system in different levels of agencies. Furthermore, the adaptability of human resources in adopting a new information system also plays an important part.
  • Serrana, J. M., B. Li, T. Sumi, Y. Takemon, and K. Watanabe
    bioRxiv doi: https://doi.org/10.1101/2020.01.25.919381 2020年01月 研究論文(学術雑誌)
  • Von Ralph, Dane Marquez Herbuela, Tomonori Karita, Micanaldo Ernesto Francisco, Kozo Watanabe
    JMIR Formative Research 4 1 e16424  2020年01月 [査読有り]
     研究論文(学術雑誌) 
    Background For the last 10 years, mobile phones have provided the global health community with innovative and cost-effective strategies to address the challenges in the prevention and management of dengue fever. Objective The aim is to introduce and describe the design and development process of Mozzify, an integrated mobile health (mHealth) app that features real-time dengue fever case reporting and mapping system, health communication (real-time worldwide news and chat forum/timeline, within-app educational videos, links to local and international health agency websites, interactive signs and symptoms checker, and a hospital directions system), and behavior modification (reminders alert program on the preventive practices against dengue fever). We also aim to assess Mozzify in terms of engagement and information-sharing abilities, functionality, aesthetics, subjective quality, and perceived impact. Methods The main goals of the Mozzify app were to increase awareness, improve knowledge, and change attitudes about dengue fever, health care-seeking behavior, and intention-to-change behavior on preventive practices for dengue fever among users. It was assessed using the Mobile Application Rating Scale (MARS) among 50 purposively sampled individuals: public health experts (n=5), environment and health-related researchers (n=23), and nonclinical (end users) participants (n=22). Results High acceptability and excellent satisfaction ratings (mean scores ≥4.0 out of 5) based on the MARS subscales indicate that the app has excellent user design, functionality, usability, engagement, and information among public health experts, environment and health-related researchers, and end users. The app’s subjective quality (recommending the app to other people and the app’s overall star rating), and specific quality (increase awareness, improve knowledge, and change attitudes about dengue fever; health care-seeking behavior; and intention-to-change behavior on preventive practices for dengue fever) also obtained excellent satisfaction ratings from the participants. Some issues and suggestions were raised during the focus group and individual discussions regarding the availability of the app for Android devices, language options limitations, provision of predictive surveillance, and inclusion of other mosquito-borne diseases. Conclusions Mozzify may be a promising integrated strategic health intervention system for dengue fever case reporting and mapping; increase awareness, improve knowledge, and change attitude about dengue fever; and disseminating and sharing information on dengue fever among the general population and health experts. It also can be an effective aid in the successful translation of knowledge on preventive measures against dengue fever to practice.
  • Dávid Murányi, Maribet Gamboa, Kozo Watanabe
    Zootaxa 4718 1 57 - 66 2020年01月 [査読有り]
     研究論文(学術雑誌) 
    Copyright © 2020 Magnolia Press A new species of the genus Protonemura Kempny, 1898 (Plecoptera: Nemouridae: Amphinemurinae) is described from the Ishizuchi Range of Shikoku Island, Japan, based on the male, female and Co1 sequences. Protonemura shimizui Murányi & Gamboa sp. n. belongs to the P. orbiculata species group sensu Shimizu, 1998. The new species appears to be limited to the higher elevations of the Ishizuchi Range. Faunistic survey of the high elevation rheocrenes of the Ishizuchi Range is also presented.
  • Von Ralph Dane M. Herbuela, Ferdinand S. de Guzman, Girly D. Sobrepeña, Andrew Benedict F. Claudio, Angelica Cecilia V. Tomas, Carmina M.Arriola Delos Reyes, Rachele A. Regalado, Mariama M. Teodoro, Kozo Watanabe
    International Journal of Environmental Research and Public Health 17 1 99  2020年01月 [査読有り]
     研究論文(学術雑誌) 
    © 2019 by the authors. Licensee MDPI, Basel, Switzerland. Background: Psychiatric symptoms have been reported in adult patients with dengue fever (DF); however, information on pediatric patients remains inadequate. We sought to identify the prevalence and predictors of depressive and anxiety symptoms and identify other psychiatric symptoms among pediatric patients with DF. This case-control study involved pediatric in-patients (n = 225) who had clinical or serologic-confirmed DF and healthy school-based controls (n = 260). Participants completed the Revised Child Anxiety and Depression Scale (RCADS). Results: The prevalence of depressive (13.3%) and anxiety (34.2%) symptoms among pediatric patients with DF was significantly (p < 0.001) higher than that among controls (3.5% and 16.2%, respectively). Multiple linear regression analysis found that age, family history of DF, ≤2 days of hospitalization, myalgia, and arthralgia were predictors of increased depressive and anxiety symptoms among the patients. Further, 26.7% of pediatric patients reported irritability, agitation, visual hallucinations, and aggressiveness. Conclusion: Pediatric patients present depressive and anxiety symptoms whose levels were associated with social and clinical factors. However, whether these symptoms are present only during the infection or may still persist after recovery or are brought by children’s adverse reactions to hospitalization are unknown, and thus, further studies are needed.
  • Von Ralph Dane M. Herbuela, Ferdinand S. de Guzman, Girly D. Sobrepeña, Andrew Benedict F. Claudio, Angelica Cecilia V. Tomas, Carmina M.Arriola Delos Reyes, Rachele A. Regalado, Mariama M. Teodoro, Kozo Watanabe
    International Journal of Environmental Research and Public Health 16 23 4705  2019年12月 [査読有り]
     研究論文(学術雑誌) 
    © 2019 by the authors. Licensee MDPI, Basel, Switzerland. Background: Knowledge, attitude, and practice (KAP) of in-patients with dengue fever (DF) through hospital-based surveillance has not been done. This study aimed to assess and compare the KAP, identify its predictors, correlation, and protective factors among pediatric and adult patients with DF and community-based controls to structure proactive community-wide DF prevention and control programs. Methods: This case-control study involved clinically or serologically confirmed patients (pediatrics n = 233; adults n = 17) with DF admitted in three public hospitals and community-based controls in Metro Manila, Philippines. A pretested structured KAP questionnaire was administered to participants to assess their KAP. Results: Pediatric and adult patients had significantly lower mean scores in the practice (p < 0.001) domain compared with the pediatric and adult controls. Being in senior high school, having had days in hospital, and rash were predictors of KAP among pediatric patients. Knowledge and attitude of patients with DF did not correlate with their practices against DF. Use of mosquito-eating fish, screen windows, and dengue vaccine were protective factors against DF. Conclusion: The study highlights the importance of behavioral change for knowledge and attitude to have significant effect to practices against DF. Thus, we recommend two comprehensive health programs, Communication for Behavioral Impact (COMBI) and Health Belief Model (HBM).
  • Takahashi, S, Y. Takemon, T. Omura, K. Watanabe
    bioRxiv doi.org/10.1101/870717 2019年12月 研究論文(その他学術会議資料等)
  • Regilme, M. A. F, M. Sato, T. Tamura, R. Arai, M. O. Sato, S. Ikeda, M. Doi, K. Tanaka, M. Gamboa, M. T. Monaghan, K. Watanabe
    bioRxiv doi.org/10.1101/862904 2019年12月 研究論文(その他学術会議資料等)
  • Joeselle M Serrana, Naoto Ishitani, Thaddeus M Carvajal, Billy Joel M Almarinez, Alberto T Barrion, Divina M Amalin, Kozo Watanabe
    Insects 10 11 374  2019年10月 [査読有り]
     研究論文(学術雑誌) 
    Despite the fact that massive outbreaks of the coconut scale insect pest, Aspidiotus rigidus Reyne (Hemiptera: Diaspididae) are inflicting significant economic losses to the Philippines' coconut industry, little is known about the population and dispersal history of this invasive pest in the country. Here, we examined the genetic diversity, structure and demographic history of A. rigidus sampled from localities with reported outbreaks from 2014 to 2017. We analyzed the genetic structure of the outbreak populations using mitochondrial COI and nuclear EF-1α markers. Both markers and all methods of population genetic structure analyses indicate clear differentiation among the A. rigidus populations separating the north from the southern regions of the Philippines. Very low or no genetic differentiation was observed within and amongst the populations per geographic region indicating two unrelated outbreak events of the pest originating from two genetically uniform populations isolated in each respective region. Historical data supports the resurgence of an established A. rigidus population in the south which could have been driven by sudden climatic changes or human-induced habitat imbalance. Our study provides valuable information on the genetic differentiation of the two A. rigidus groups that would be useful for developing and implementing biological control strategies against this pest in the Philippines.
  • Gamboa, M, J. Serrana, Y. Takemon, M. T. Monaghan, K. Watanabe
    bioRxiv doi.org/10.1101/765578 2019年09月 研究論文(その他学術会議資料等)
  • Thaddeus M. Carvajal, Kazuki Hashimoto, Reza Kurniawan Harnandika, Divina M. Amalin, Kozo Watanabe
    Parasites & vectors 12 1 361 - 361 2019年07月 [査読有り]
     研究論文(学術雑誌) 
    BACKGROUND: Recent reports reveal the presence of Wolbachia in Ae. aegypti. Our study presents additional support for Wolbachia infection in Ae. aegypti by screening field-collected adult mosquitoes using two Wolbachia-specific molecular makers. METHODS: A total of 672 Ae. aegypti adult mosquitoes were collected from May 2014 to January 2015 in Metropolitan Manila. Each individual sample was processed and screened for the presence of Wolbachia by selected markers, Wolbachia-specific 16S rDNA and its surface protein (wsp), under optimized PCR conditions and sequenced. RESULTS: Totals of 113 (16.8%) and 89 (13.2%) individual mosquito samples were determined to be infected with Wolbachia using the wsp and 16S rDNA markers, respectively. The Ae. aegpyti wsp sample sequences were similar or identical to five known Wolbachia strains belonging to supergroups A and B while the majority of 16S rDNA sample sequences were similar to strains belonging to supergroup B. Overall, 80 (11.90%) individual mosquito samples showed positive amplifications in both markers and 69% showed congruence in supergroup identification (supergroup B). CONCLUSIONS: By utilizing two Wolbachia-specific molecular makers, our study demonstrated the presence of Wolbachia from individual Ae. aegypti samples. Our results showed a low Wolbachia infection rate and inferred the detected strains belong to either supergroups A and B.
  • Faridah, L, N. Fauziah, S Ekawardhani, Riyadi, K. Watanabe
    Journal of Clinical and Diagnostic Research 13 7 DC20 - DC23 2019年07月 [査読有り]
     研究論文(学術雑誌)
  • Joeselle M. Serrana, Yo Miyake, Maribet Gamboa, Kozo Watanabe
    ECOLOGICAL INDICATORS 101 963 - 972 2019年06月 [査読有り]
     研究論文(学術雑誌) 
    Conventional morphology-based identification is commonly used for routine assessment of freshwater ecosystems. However, cost and time efficient techniques such as high-throughput sequencing (HTS) based approaches may resolve the constraints encountered in conducting morphology-based surveys. Here, we characterized stream macroinvertebrate species diversity and community composition via metabarcoding and morphological analysis from environmental samples collected from the Shigenobu River Basin in Ehime Prefecture, Japan. We compared diversity metrics and assessed both approaches' ability to evaluate the relationship between macroinvertebrate community and environmental variables. In total, we morphologically identified 45 taxa (3 families, six subfamilies, 31 genera, and five species) from 8,276 collected individuals from ten study sites. We detected 44 species by metabarcoding, with 35 species collapsed into 11 groups matching the morphologically identified taxa. A significant positive correlation between logged depth (number of HTS reads) and abundance of morphological taxa was observed, which implied that quantitative data could be used for subsequent analyses. We recovered a considerably high rate of relative abundance detection of the morphologically identified samples. Recovery of samples by incidence or presence/absence count were considerably low, with a high rate of false-negative detection specifically for species with scarce representation in the community sample. Given the low taxonomic resolution of the morphological assignment in this study, we report that metabarcoding does not reflect the majority of the species naturally occurring in our site, which could further be proven by performing refined morphological assessment of the samples. However, abundance-based detection proved to be efficient with 92% of the individuals correctly demonstrated. We conclude that DNA metabarcoding provides a practical and cost-effective approach especially for rapid biological monitoring of freshwater macroinvertebrate communities, but further improvements in the detection of scarce samples should be considered to increase the sensitivity of detecting most, if not all, of the species present in the environment.
  • Maribet Gamboa, Kozo Watanabe
    BMC Genomics 20 1 84 - 84 2019年01月 [査読有り]
     研究論文(学術雑誌) 
    © 2019 The Author(s). Background: Environmental heterogeneity continuously produces a selective pressure that results in genomic variation among organisms; understanding this relationship remains a challenge in evolutionary biology. Here, we evaluated the degree of genome-environmental association of seven stonefly species across a wide geographic area in Japan and additionally identified putative environmental drivers and their effect on co-existing multiple stonefly species. Double-digest restriction-associated DNA (ddRAD) libraries were independently sequenced for 219 individuals from 23 sites across four geographical regions along a nationwide latitudinal gradient in Japan. Results: A total of 4251 candidate single nucleotide polymorphisms (SNPs) strongly associated with local adaptation were discovered using Latent mixed models; of these, 294 SNPs showed strong correlation with environmental variables, specifically precipitation and altitude, using distance-based redundancy analysis. Genome-genome comparison among the seven species revealed a high sequence similarity of candidate SNPs within a geographical region, suggesting the occurrence of a parallel evolution process. Conclusions: Our results revealed genomic signatures of local adaptation and their influence on multiple, co-occurring species. These results can be potentially applied for future studies on river management and climatic stressor impacts.
  • Maribet Gamboa, David Muranyi, Shota Kanmori, Kozo Watanabe
    PLoS ONE 14 1 e0210269  2019年01月 [査読有り]
     研究論文(学術雑誌) 
    © 2019 Gamboa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The generation of the high species diversity of insects in Japan was profoundly influenced by the formation of the Japanese Archipelago. We explored the species diversification and biogeographical history of the Nemouridae Billberg, 1820 family in the Japanese Archipelago using mitochondrial DNA and nuclear DNA markers. We collected 49 species among four genera: Indonemoura Baumann, 1975; Protonemura Kempny, 1898; Amphinemura, Ris 1902 and Nemoura Latreille, 1796 in Japan, China, South Korea and North America. We estimated their divergence times—based on three molecular clock node calibrations—using Bayesian phylogeography approaches. Our results suggested that Japanese Archipelago formation events resulted in diversification events in the middle of the Cretaceous (<120 Ma), speciation in the Paleogene (<50 Ma) and intra-species diversification segregated into eastern and western Japan of the Fossa Magna region at late Neogene (20 Ma). The Indonemoura samples were genetically separated into two clades—that of Mainland China and that of Japan. The Japanese clade clustered with the Nemouridae species from North America, suggesting the possibility of a colonisation event prior to the formation of the Japanese Archipelago. We believe that our results enhanced the understanding both of the origin of the species and of local species distribution in the Japanese Archipelago.
  • Joeselle M. Serrana, Sakiko Yaegashi, Shunsuke Kondoh, Bin Li, Christopher T. Robinson, Kozo Watanabe
    Scientific Reports 8 1 10185 - 10185 2018年12月 [査読有り]
     研究論文(学術雑誌) 
    © 2018 The Author(s). Sediment bypass tunnels (SBTs) are guiding structures used to reduce sediment accumulation in reservoirs during high flows by transporting sediments to downstream reaches during operation. Previous studies monitoring the ecological effects of SBT operations on downstream reaches suggest a positive influence of SBTs on riverbed sediment conditions and macroinvertebrate communities based on traditional morphology-based surveys. Morphology-based macroinvertebrate assessments are costly and time-consuming, and the large number of morphologically cryptic, small-sized and undescribed species usually results in coarse taxonomic identification. Here, we used DNA metabarcoding analysis to assess the influence of SBT operations on macroinvertebrates downstream of SBT outlets by estimating species diversity and pairwise community dissimilarity between upstream and downstream locations in dam-fragmented rivers with operational SBTs in comparison to dam-fragmented (i.e., no SBTs) and free-flowing rivers (i.e., no dam). We found that macroinvertebrate community dissimilarity decreases with increasing operation time and frequency of SBTs. These factors of SBT operation influence changes in riverbed features, e.g. sediment relations, that subsequently effect the recovery of downstream macroinvertebrate communities to their respective upstream communities. Macroinvertebrate abundance using morphologically-identified specimens was positively correlated to read abundance using metabarcoding. This supports and reinforces the use of quantitative estimates for diversity analysis with metabarcoding data.
  • Thaddeus Carvajal, Jayson Dale Capistrano, Kazuki Hashimoto, Kristin Joyce Go, Maria Angeline Isabelle Cruz, Monique Johanne Lourdee Martinez, Vincent Stefano Tiopianco, Divina Amalin, Kozo Watanabe
    Journal of Vector Borne Diseases 55 4 265 - 270 2018年12月 [査読有り]
     研究論文(学術雑誌) 
    © 2018 E-Flow Wolters Kluwer Medknow Publications. All rights reserved. Background & objectives: Culex quinquefasciatus is a peridomestic mosquito known for its ability to transmit pathogenic diseases such as filariasis and Japanese encephalitis. The development and use of novel and innovative vector control measures such as the utilization of Wolbachia, along with the existing ones, are necessary to prevent the transmission of these diseases. Studies exploring the diversity of Wolbachia, particularly in Cx. quinquefasciatus are very limited in the Philippines. Thus, the aim of the study was to detect the presence, distribution, and phylogenetic relationship of Wolbachia infections in Cx. quinquefasciatus in Metropolitan Manila, Philippines. Methods: Adult Cx. quinquefasciatus mosquitoes were collected using a commercially available light-trap from May 2014-January 2015. Based on their sampling grids (n = 51), the adult mosquito abdomens were pooled and subjected to Wolbachia surface protein (wsp) gene amplification assay. Five selected wsp-positive samples were then sequenced and further analyzed to infer their phylogenetic relationship with known Wolbachia strains. Results: A total of 1090 adult Cx. quinquefasciatus mosquitoes were collected. Pooled abdomens (n = 53) were then sorted based on their sampling grids for subsequent screening of wsp gene. Wolbachia infection rate was 59% (31/53). These infections were located at 29 (57%) sampling grids, and were observed to be widely distributed in the study area. Phylogenetic analysis indicated that the sample sequences were Wolbachia pipientis isolated from known hosts, Cx. pipiens and Cx. quinquefasciatus belonging to supergroup B clade. Interpretation & conclusion: The study was able to demonstrate the prevalence and distribution of Wolbachia in Cx. quinquefasciatus in Metropolitan Manila, Philippines. The findings of this study are geared towards proposing a vector control program that utilizes the potential of Wolbachia as a biological control agent in preventing the transmission of Culex-borne diseases.
  • Howell T. Ho, Thaddeus M. Carvajal, John Robert Bautista, Jayson Dale R. Capistrano, Katherine M. Viacrusis, Lara Fides T. Hernandez, Kozo Watanabe
    Tropical Medicine and Infectious Disease 3 4 118  2018年11月 [査読有り]
     研究論文(学術雑誌) 
    © 2018 by the authors. Dengue is a major public health concern and an economic burden in the Philippines. Despite the country's improved dengue surveillance, it still suffers from various setbacks and needs to be complemented with alternative approaches. Previous studies have demonstrated the potential of Internet-based surveillance such as Google Dengue Trends (GDT) in supplementing current epidemiological methods for predicting future dengue outbreaks and patterns. With this, our study has two objectives: (1) assess the temporal relationship of weekly GDT and dengue incidence in Metropolitan Manila from 2009–2014; and (2) examine the health-seeking behavior based on dengue-related search queries of the population. The study collated the population statistics and reported dengue cases in Metropolitan Manila from respective government agencies to calculate the dengue incidence (DI) on a weekly basis for the entire region and annually per city. Data processing of GDT and dengue incidence was performed by conducting an ‘adjustment' and scaling procedures, respectively, and further analyzed for correlation and cross-correlation analyses using Pearson's correlation. The relative search volume of the term ‘dengue' and top dengue-related search queries in Metropolitan Manila were obtained and organized from the Google Trends platform. Afterwards, a thematic analysis was employed, and word clouds were generated to examine the health behavior of the population. Results showed that weekly temporal GDT pattern are closely similar to the weekly DI pattern in Metropolitan Manila. Further analysis showed that GDT has a moderate and positive association with DI when adjusted or scaled, respectively. Cross-correlation analysis revealed a delayed effect where GDT leads DI by 1–2 weeks. Thematic analysis of dengue-related search queries indicated 5 categories namely; (a) dengue, (b) sign and symptoms of dengue, (c) treatment and prevention, (d) mosquito, and (e) other diseases. The majority of the search queries were classified in ‘signs and symptoms' which indicate the health-seeking behavior of the population towards the disease. Therefore, GDT can be utilized to complement traditional disease surveillance methods combined with other factors that could potentially identify dengue hotspots and help in public health decisions.
  • マニラ首都圏におけるデング熱媒介蚊の産卵活動に関わる因子の時空間的分析
    糠澤桂, 西元竣哉, 鈴木祥広, 渡辺幸三
    土木学会論文集G(環境) Vol.74, No.5, pp.I_79-I_85, No.5 I_79 - I_85 2018年09月 [査読有り]
     研究論文(学術雑誌)
  • Andri Taruna Rachmadi, Masaaki Kitajima, Kozo Watanabe, Sakiko Yaegashi, Joeselle Serrana, Arata Nakamura, Toyoko Nakagomi, Osamu Nakagomi, Kazuhiko Katayama, Satoshi Okabe, Daisuke Sano
    Applied and Environmental Microbiology 84 13 e00244-18  2018年07月 [査読有り]
     研究論文(学術雑誌) 
    © 2018 American Society for Microbiology. Human noroviruses are excreted in feces from infected individuals and included in wastewater. It is critical to remove/inactivate them in wastewater treatment processes, particularly in the disinfection step, before release to aquatic environments. However, the high mutation rates of human noroviruses raise concerns about the emergence of strains that are less susceptible to disinfectants and can survive even after wastewater treatment. This study aimed to demonstrate the strain-dependent susceptibility of norovirus to free chlorine. A population originated from the murine norovirus strain S7-PP3, a surrogate for human noroviruses in environmental testing, was exposed to free chlorine and then propagated in a host cell. This cycle of free chlorine exposure followed by propagation in cells was repeated 10 times, and populations with lower susceptibility to free chlorine were obtained from two independent trials of chlorine exposure cycles. Open reading frame 2 (ORF2) and ORF3 of the murine norovirus genome were analyzed by next-generation sequencing, and a unique nonsynonymous mutation (corresponding to a change from phenylalanine to serine) at nucleotide (nt) 7280 in ORF3, which encodes the minor capsid protein VP2, was found in chlorine-exposed populations from both trials. It was confirmed that all of the clones from the chlorine-treated population had lower susceptibility to free chlorine than those from the control population. These results indicate that exposure to free chlorine and dilution exert different driving forces to form murine norovirus (MNV) quasispecies, and that there is a selective force to form MNV quasispecies under free chlorine exposure.
  • Thaddeus M. Carvajal, Katherine M. Viacrusis, Lara Fides T. Hernandez, Howell T. Ho, Divina M. Amalin, Kozo Watanabe
    BMC Infectious Diseases 18 1 183 - 183 2018年04月 [査読有り]
     研究論文(学術雑誌) 
    © 2018 The Author(s). Background: Several studies have applied ecological factors such as meteorological variables to develop models and accurately predict the temporal pattern of dengue incidence or occurrence. With the vast amount of studies that investigated this premise, the modeling approaches differ from each study and only use a single statistical technique. It raises the question of whether which technique would be robust and reliable. Hence, our study aims to compare the predictive accuracy of the temporal pattern of Dengue incidence in Metropolitan Manila as influenced by meteorological factors from four modeling techniques, (a) General Additive Modeling, (b) Seasonal Autoregressive Integrated Moving Average with exogenous variables (c) Random Forest and (d) Gradient Boosting. Methods: Dengue incidence and meteorological data (flood, precipitation, temperature, southern oscillation index, relative humidity, wind speed and direction) of Metropolitan Manila from January 1, 2009 - December 31, 2013 were obtained from respective government agencies. Two types of datasets were used in the analysis; observed meteorological factors (MF) and its corresponding delayed or lagged effect (LG). After which, these datasets were subjected to the four modeling techniques. The predictive accuracy and variable importance of each modeling technique were calculated and evaluated. Results: Among the statistical modeling techniques, Random Forest showed the best predictive accuracy. Moreover, the delayed or lag effects of the meteorological variables was shown to be the best dataset to use for such purpose. Thus, the model of Random Forest with delayed meteorological effects (RF-LG) was deemed the best among all assessed models. Relative humidity was shown to be the top-most important meteorological factor in the best model. Conclusion: The study exhibited that there are indeed different predictive outcomes generated from each statistical modeling technique and it further revealed that the Random forest model with delayed meteorological effects to be the best in predicting the temporal pattern of Dengue incidence in Metropolitan Manila. It is also noteworthy that the study also identified relative humidity as an important meteorological factor along with rainfall and temperature that can influence this temporal pattern.
  • Bin Li, Yang Yang, Sai Wang, Ming Wang, Kozo Watanabe
    Wetlands 38 2 391 - 399 2018年04月 [査読有り]
     研究論文(学術雑誌) 
    © 2017, Society of Wetland Scientists. Constructed wetlands (CWs) for wastewater treatment had drawn much attention for their additional function of conserving freshwater ecosystems. The purpose of this study was to evaluate the macroinvertebrate biodiversity of two subsurface-flow and surface-flow hybrid CW systems (Qimei CW system (QCWS) and Kejiyuan CW system (KCWS)) under high and low pollutant stress in China. Nonmetric multidimensional scaling (NMDS) and canonical correspondence analysis (CCA) were used to analyze the water quality and aquatic macroinvertebrates community data. The results indicated that the subsurface-flow CW could conserve significant macroinvertebrate biodiversity (total taxon richness 17). The community structure was influenced by habitat types (i.e., subsurface-flow vs. surface-flow CWs) under low pollutant stress, and this influence was somehow masked by influence of water quality under high pollutant stress. Good pollutant removal rates were obtained in decreasing the concentrations of total nitrogen (66.37% and 27.28%), total phosphorus (58.93% and 37.55%), and loadings of biochemical oxygen demand (28.38% and 73.71%) in QCWS and KCWS, respectively. This study implied that subsurface-flow CWs could achieved good performance in both water purification and biodiversity conservation, which could provide a more solid basis for the application of subsurface-flow CWs.
  • Andri Taruna Rachmadi, Masaaki Kitajima, Kozo Watanabe, Satoshi Okabe, Daisuke Sano
    Environmental science & technology 52 5 2434 - 2435 2018年03月 [査読有り]
     研究論文(学術雑誌)
  • Maribet Gamboa, Maria Claret Tsuchiya, Suguru Matsumoto, Hisato Iwata, Kozo Watanabe
    Archives of insect biochemistry and physiology 96 3 2017年11月 [査読有り]
     研究論文(学術雑誌) 
    Proteome variation among natural populations along an environmental gradient may provide insights into how the biological functions of species are related to their local adaptation. We investigated protein expression in five stream stonefly species from four geographic regions along a latitudinal gradient in Japan with varying climatic conditions. The extracted proteins were separated by two-dimensional gel electrophoresis and identified by matrix-assisted laser desorption/ionization of time-of-flight (MALDI TOF/TOF), yielding 446 proteins. Low interspecies variation in the proteome profiles was observed among five species within geographical regions, presumably due to the co-occurring species sharing the environments. However, large spatial variations in protein expression were found among four geographic regions, suggesting strong regulation of protein expression in heterogeneous environments, where the spatial variations were positively correlated with water temperature. We identified 21 unique proteins expressed specifically in a geographical region and six common proteins expressed throughout all regions. In warmer regions, metabolic proteins were upregulated, whereas proteins related to cold stress, the photoperiod, and mating were downregulated. Oxygen-related and energy-production proteins were upregulated in colder regions with higher altitudes. Thus, our proteomic approach is useful for identifying and understanding important biological functions related to local adaptations by populations of stoneflies.
  • 八重樫咲子, 細川大樹, 渡辺幸三
    土木学会論文集G(環境) 73 7 III_139 - III_147 2017年11月 [査読有り]
  • Kozo Watanabe, Michael T Monaghan
    Evolution; international journal of organic evolution 71 7 1755 - 1764 2017年07月 [査読有り]
     研究論文(学術雑誌) 
    A fundamental question linking population genetics and community ecology is how adaptive processes (e.g., natural selection) and neutral processes (e.g., drift-migration equilibrium) underpin the species-genetic diversity correlation (SGDC). Here, we combine genome scans and outlier loci detection with community analysis to separately test for neutral and nonneutral SGDCs in four species of stream insect. We sampled 60 localities in Japan and examined the relationships among population AFLP band richness (Br), taxon richness of the total community (S) and of the trophic guild (Str ), and 15 habitat parameters that could potentially drive adaptation and influence richness. Neutral Br was positively correlated with S only in the dominant species of these communities, suggesting Br may be constrained when intraspecific competition is pronounced. Nonneutral Br was correlated with Str in a species restricted to high elevations where habitat heterogeneity was highest. Community distance and genetic distance (β-SGDC) was correlated in two of the four species at both neutral and nonneutral loci. Distance-based redundancy analysis found geographic isolation and elevation to drive divergence of both communities and populations. This suggests that both neutral and adaptive divergence occurred through the shared influences of geographic isolation and local adaptation at the two levels of diversity.
  • Weihai Li, Dávid Murányi, Maribet Gamboa, Ding Yang, Kozo Watanabe
    Zootaxa 4243 1 165 - 176 2017年03月 [査読有り]
     研究論文(学術雑誌) 
    © 2017 Magnolia Press. The species of Leuctridae (Plecoptera) from Guangxi, China are reviewed. Two species of Rhopalopsole are described as new to science, R. cestroidea sp. nov. and R. triangulis sp. nov., belonging to the R. vietnamica group and the R. magnicerca group, respectively. Six species of Leuctridae are now known for Guangxi including two additional species of Rhopalopsole and one Paraleuctra recorded for the first time. The previously unknown female of R. duyuzhoui Sivec &Harper, 2008 is described from specimens from Guangxi. Characters are illustrated for the separation of R. furcospina (Wu, 1973) and R. sinensis Yang &Yang, 1993. Mitochondrial sequences of five Rhopalopsole species support their specific recognition.
  • Kei Nukazawa, So Kazama, Kozo Watanabe
    ECOHYDROLOGY 10 1 e1778  2017年01月 [査読有り]
     研究論文(学術雑誌) 
    Species distribution models were developed to predict the spatial patterns of the species diversity and the genetic diversity of stream organisms using a distributed hydrological model. We derived annual metrics of water depth and flow velocity in rivers using a hydrological model covering an entire catchment in northeastern Japan. We acquired geospatial data throughout the catchment and the presence records of six taxa within the part of the catchment. Subsequently we derived habitat suitability indices (HSIs) for these taxa using a frequency analysis or the maximum-entropy approach (MaxEnt) to predict three metrics of species diversity. The Shannon-Wiener's diversity index based on MaxEnt (Shannon_MaxE) most effectively represented empirical taxon richness. Subsequently, by comparing Shannon_MaxE and empirical genetic diversity for the four species of stream insects, we evaluated species-genetic diversity correlations (SGDCs). Of the four species, only one caddisfly species (Hydropsyche orientalis) displayed significant positive SGDCs. The result reflects the broad habitat range of this taxon throughout the catchment and its poor dispersal ability, whereas the other three species lacked SGDCs and displayed either a strong dispersal potential (Stenopsyche marmorata and Ephemera japonica) or a narrower habitat range within upstream domains (Hydropsyche albicephala). Finally, we estimated the spatial distribution of genetic diversity of H. orientalis populations based on the calculated Shannon_MaxE using the positive SGDC. This framework is promising for projecting future biodiversity in the context of anthropogenic perturbations such as climate change.
  • Fuminari Miura, Toru Watanabe, Kozo Watanabe, Kazuhiko Takemoto, Kensuke Fukushi
    Journal of environmental sciences (China) 50 13 - 20 2016年12月 [査読有り]
     研究論文(学術雑誌) 
    Diarrheal diseases can be transmitted via both primary infection due to exposures to contaminated materials from the environment and secondary infection due to person-to-person contacts. Usually, the importance of secondary infection is empirically assessed by fitting mathematical models to the epidemic curves. However, these empirical models may not be applicable to other epidemic cases because they are developed only for the target epidemics and they don't consider the detail routes of infection. In our previous study, we developed a theoretical model taking into account the various routes of infection that commonly occur in households (e.g., shaking hands, food handling, and changing diapers). This model was made flexible and applicable to any epidemics by means of adjusting model parameters. In this study, we proposed a new index "Vulnerability indicator to secondary infection (VISI)", which expressed a ratio of secondary infection to primary infection risks and calculated this index in a simulated norovirus (NoV) epidemic that involved 10,000 households. The results demonstrated that households composed of more than three members including infant(s) had much higher levels of VISI (5-45) than two-member-households with VISI (0.1-4). These results concluded that the infants were likely to be a hub of secondary infections in highly dense families and therefore careful handling of diapers was deemed indispensible in such families to effectively control the secondary infections.
  • 渡辺幸三, 近藤俊介, 泉昂佑, 八重樫咲子
    土木学会論文集G(環境) 72 7 III_489 - III_496 2016年12月 [査読有り]
     研究論文(学術雑誌)
  • 八重樫咲子, 泉昴佑, 三宅洋, 渡辺幸三
    土木学会論文集G(環境) 72 7 III_115 - III_122 2016年12月 [査読有り]
     研究論文(学術雑誌)
  • Thaddeus M. Carvajal, Lara Fides T. Hernandez, Howell T. Ho, Menard G. Cuenca, Biancamarie C. Orantia, Camille R. Estrada, Katherine M. Viacrusis, Divina M. Amalin, Kozo Watanabe
    Journal of Vector Borne Diseases 53 2 127 - 135 2016年06月 [査読有り]
     研究論文(学術雑誌) 
    Background & objectives: Aedes aegypti (L.) is an efficient vector for arboviral diseases such as dengue. The wings of Ae. aegypti has been extensively studied in order to investigate population heterogeneity and structure by utilizing a landmark based geometric morphometrics (GMs) approach. The aim of this study was to examine and assess the wing geometry of Ae. aegypti in Metropolitan Manila. Methods: In total, 312 Ae. aegypti mosquitoes were collected from 98 sampling points using a mosquito light-trap from May 2014 to January 2015. A complete coverage of the wing was achieved by removing wing scales with chemical and physical treatment, leading to identification of 26 landmarks. Geometric morphometric analyses were employed and the spatial distance pattern was estimated using isolation by distance (IBD) and spatial autocorrelation (SA). Results: The results of the GM analyses revealed population heterogeneity and structuring in Ae. aegypti populations for both sexes using principal component and canonical variate analyses respectively. Moreover, IBD and SA only detected significant spatial structure in male Ae. aegypti populations while female population structures were homogeneous throughout the geographical area. Interpretation & conclusion: The newly modified wing preparation procedure was able to capture a complete coverage of the wings of Ae. aegypti, thus providing a stronger separation power for very close populations in an urban area. It is also noteworthy that the results of IBD and SA supported the findings of GM in the population structuring of male and female Ae. aegypti. The outcome of the study increases our understanding of the vector, which would be useful in developing effective control strategies.
  • Bin Li, Kozo Watanabe, Dong-Hwan Kim, Sang-Bin Lee, Muyoung Heo, Heui-Soo Kim, Tae-Soo Chon
    WATER 8 5 2016年05月 [査読有り]
     研究論文(学術雑誌) 
    Water quality maintenance should be considered from an ecological perspective since water is a substrate ingredient in the biogeochemical cycle and is closely linked with ecosystem functioning and services. Addressing the status of live organisms in aquatic ecosystems is a critical issue for appropriate prediction and water quality management. Recently, genetic changes in biological organisms have garnered more attention due to their in-depth expression of environmental stress on aquatic ecosystems in an integrative manner. We demonstrate that genetic diversity would adaptively respond to environmental constraints in this study. We applied a self-organizing map (SOM) to characterize complex Amplified Fragment Length Polymorphisms (AFLP) of aquatic insects in six streams in Japan with natural and anthropogenic variability. After SOM training, the loci compositions of aquatic insects effectively responded to environmental selection pressure. To measure how important the role of loci compositions was in the population division, we altered the AFLP data by flipping the existence of given loci individual by individual. Subsequently we recognized the cluster change of the individuals with altered data using the trained SOM. Based on SOM recognition of these altered data, we determined the outlier loci (over 90th percentile) that showed drastic changes in their belonging clusters (D). Subsequently environmental responsiveness (E-k') was also calculated to address relationships with outliers in different species. Outlier loci were sensitive to slightly polluted conditions including Chl-a, NH4-N, NOX-N, PO4-P, and SS, and the food material, epilithon. Natural environmental factors such as altitude and sediment additionally showed relationships with outliers in somewhat lower levels. Poly-loci like responsiveness was detected in adapting to environmental constraints. SOM training followed by recognition shed light on developing algorithms de novo to characterize loci information without a priori knowledge of population genetics.
  • Kei Wakimura, Yasuhiro Takemon, Atsushi Takayanagi, Shin-ichi Ishiwata, Kozo Watanabe, Kazumi Tanida, Nobuyoshi Shimizu, Mikio Kato
    DNA Barcodes 4 1 - 25 2016年04月 [査読有り]
     研究論文(学術雑誌) 
    We have determined nucleotide sequences of three genes encoding histone H3, 18S rRNA, and mitochondrial cytochrome oxidase subunit I (COI) from the mayfly community in Eastern Asia. All sequence data collected from 303 specimens comprising 80 taxa (63 identified to species, 14 to genus, and 3 to family) were deposited in GenBank/ EMBL/ DDBJ International Databases for further expansion of DNA barcoding projects of mayflies. Phylogenetic analysis based on the neighborjoining method among the three genes found that COI and H3 genes had relatively high evolutionary rates, and were not suitable in inferring phylogenetic relationships among families within the orders but were useful in identifying species (i.e., DNA barcoding). In contrast, the more conserved 18S rRNA gene was adequately informative for elucidating inter-family divergence, but not suitable for species identification.
  • 糠澤 桂, 風間 聡, 渡辺 幸三
    水工学論文集 Annual journal of Hydraulic Engineering, JSCE 60 Ⅰ_433 - 438 土木学会 2016年03月 [査読有り]
  • Kei Nukazawa, So Kazama, Kozo Watanabe
    11TH INTERNATIONAL SYMPOSIUM ON ECOHYDRAULICS 2016年 [査読有り]
     研究論文(国際会議プロシーディングス) 
    Among key components threatening global biodiversity in the future, such as land use alterations, climate changes can be primary stressors on stream ecosystems. Although many studies in the discipline of landscape genetics have tried to explore genetic consequences of oncoming climate change, most of them used anonymous genes, even though the majority of these genetic regions are just known to be "neutral" (no relation) to natural selection. In this study, we projected adaptive genetic variations and species distributions in four stream insect species under climate change scenarios, using a distributed hydrothermal model and 8 global climate models (GCM). We used non-neutral AFLP (Amplified Fragment Length Polymorphism) loci, which were statistically defined to be subject to natural selection, in the target species found at 11-31 out of 45 sampling localities. For modeling species distributions, we used presence data of the studied insects at the same sites as above. We acquired bias-corrected air temperature and precipitation data of 3 RCP (Representative Concentration Pathways) scenarios from the GCMs. Then, these climatic data were used to calculate annual metrics of current velocity, water depth and water temperature using the hydrothermal model. Models describing adaptive genetic variation, which is represented as linear response of allele frequency at each locus to environmental predictors, have been constructed based on current hydrothermal variables in a previous work. We used the model for estimating future ranges of the allele frequency along changing climate gradients. Finally, we projected spatial pattern of genetic diversity (heterozygosity) for the studied species. Also, we employed maximum entropy model (Maxent) to predict present and future distributions of the studied species. Degraded pattern of genetic diversity in a caddisfly species (Stenopsyche marmorata) was more notable under extreme climate scenarios when comparing with the current climate, depending on higher air temperature projected in the future. While genetic diversity in catchment scale only decreased in S. marmorata, habitat range, which was predicted by species distributions, severely contracted more in other three species than for S. marmorata.
  • 八重樫 咲子, 不破 直人, 山崎 久美子, 三宅 洋, 渡辺 幸三
    土木学会論文集G(環境) 71 7 III_115 - III_121 公益社団法人 土木学会 2015年 
    本研究では,愛媛県重信川のエルモンヒラタカゲロウ(Epeorus latifolium)の流域内遺伝子流動を明らかにした.重信川は流域中で貯水ダム,堰・砂防ダム,自然環境下で存在する瀬切れによる河川分断化が発生している河川である.遺伝子流動の解析にはミトコンドリアDNAのCytochrome Oxidase subunit I領域を対象としたDNA多型分析を用いた.その結果,貯水ダム,瀬切れによって分断された集団間では有意な遺伝的分化は認められなかった.一方で堰・砂防ダム分断区間では有意な遺伝的分化が認められた(遺伝距離=0.311-0.841,P<0.001-0.01).これは短距離に多数存在している堰・砂防ダムによってエルモンヒラタカゲロウの移動が阻害された可能性を示す.ただし,堰・砂防ダムで分断された地点間は標高差が大きいことから,地点間の水温差が成長速度の違いを生み,生殖分離が発生していた可能性もある.また,本研究で対象とした貯水ダムは湛水面積0.5km2と比較的規模が小さいため,エルモンヒラタカゲロウの移動阻害が発生しなかったと考えられる.さらに,瀬切れ区間で遺伝的分化が見られなかったことは,重信川で恒常的に自然発生する瀬切れに適応して移動する生活史を地域個体群が有している可能性を示唆している.
  • Kei Nukazawa, So Kazama, Kozo Watanabe
    JOURNAL OF BIOGEOGRAPHY 42 1 103 - 113 2015年01月 [査読有り]
     研究論文(学術雑誌) 
    AimA central question in landscape genetics is how local adaptation among heterogeneous environments leads to genetic variation in natural populations. This article has two aims: (1) to examine associations between non-neutral genetic diversity of stream insect populations and environmental heterogeneity simulated by a hydrothermal model; and (2) to establish a novel framework for simulating the spatial distribution of adaptive genetic variation at catchment scale. LocationNatori River basin, north-eastern Japan. MethodsA distributed hydrothermal model was used to simulate current velocity, water depth and water temperature throughout the basin. We used empirical genetic data from 6-21 non-neutral amplified fragment length polymorphism (AFLP) loci in four target stream insect species found at 45 sampling sites. We constructed multiple regression models using allele frequencies at the non-neutral loci as objective variables and the hydrothermal and geographical parameters as candidate explanatory variables. ResultsOf the four species, one caddisfly species provided strong evidence of local adaptation to the annual maximum water temperature. Assuming a priori that the regression models were applicable throughout the study area, we visualized the geographical distributions of genetically similar groups - UPGMA (unweighted pair group method with arithmetic mean) clusters based on genetic distance - and local genetic diversity along the simulated hydrothermal gradients. The UPGMA clusters of two caddisfly species (Hydropsyche orientalis and Stenopsyche marmorata) showed clear spatial turnover along an elevational gradient. Local genetic diversities of these species showed lower genetic diversity in lowland areas. Main conclusionsThe predicted spatial patterns along an elevational gradient could be explained by a hypothetical mechanism whereby lowland habitats only accommodate genotypes adapted to severe thermal conditions. Our approach of combining a hydrothermal simulation with genome-wide scans of non-neutral loci is promising for the identification of evolutionary associations of adaptive loci to the temporal regime of hydrothermal conditions, such as maxima and temporal variability.
  • Kozo Watanabe, Sakiko Yaegashi, Hiro Tomozawa, Shunichi Koshimura, Tatsuo Omura
    FRESHWATER BIOLOGY 59 7 1474 - 1483 2014年07月 [査読有り]
     研究論文(学術雑誌) 
    The 2011 Great East Japan Earthquake generated extreme tsunami waves that entered river mouths, causing strong and long-distance propagation along the water corridors. This study reports the first empirical survey of this rare and extreme ecological impact of tsunami propagation on river communities. We sampled macroinvertebrate communities at 15 river sites on the Sendai Plain in Northeast Japan along a gradient of tsunami disturbance intensity [i.e. altitude: range=1-29m above sea level (a.s.l.)] two and 16months after the earthquake. In comparison with data collected before the tsunami, we found evidence of significant reductions in taxon richness (-54% on average) and total abundance (-91%) after the tsunami in inundated river reaches (up to 25km from the river mouth). There were large spatial variations in local impacts, with altitudes of 7-9m a.s.l. separating heavily damaged inundated communities from intact non-inundated communities. The degraded communities exhibited variable recovery rates extending beyond 16months after the tsunami. Mobility trait analysis revealed a relatively rapid recovery of swimmers (e.g. Baetis), reflecting their high mobility and active drift behaviours in the recolonisation phase. We observed the rare phenomenon of upstream drift' of marine worms (Phyllodocidae) to freshwater rivers in three of the 10 inundated sites. These survived in fresh water for up to 14months, suggesting that some marine-derived immigrants can persist in fresh water for extended periods.
  • 糠澤 桂, 風間 聡, 高瀬 陽彦, 渡辺 幸三
    土木学会論文集B1(水工学) 70 4 I_1405 - I_1410 Japan Society of Civil Engineers 2014年03月 [査読有り]
     研究論文(学術雑誌) 
    We evaluated the linkage between genetic diversity and habitat suitability index (HSI) of aquatic animals including freshwater fishes, amphibians and macroinvertebrates in the Natori River basin located at the middle of Miyagi prefecture. The HSI has been structured by variables calculated from a distributed hydro-thermal model and GIS based geographical variables. We found a strong positive correlation between genetic diversity and HSI in one caddisfly (Hydropsychidae), indicating that a prospective habitat (i.e., locality which has high HSI) might contribute to increase in genetic diversity. The genetic diversity of one caddisfly (Hydropsychidae) had significant positive correlations with the HSIs of predatory fishes and aquatic insects. This result suggests that exposures to predation pressure can enhance genetic diversity. We derived negative correlations between genetic diversity and the HSIs within niche competitors, suggesting inter-species selective pressure constrains intra-species genetic diversity.
  • Sakiko Yaegashi, Kozo Watanabe, Michael T. Monaghan, Tatsuo Omura
    FRESHWATER SCIENCE 33 1 172 - 180 2014年03月 [査読有り]
     研究論文(学術雑誌) 
    Most population genetic studies in streams infer long-term patterns of gene flow by calculating fixation indices (e. g., F-ST) among sampled populations. In more-recent analytical methods, the need to assign individuals to populations a priori (clustering algorithms) is relaxed, and spatial autocorrelation analysis of allele frequencies (SA) is used to infer finer-scale and potentially short-term dispersal distances. We applied multiple methods to study the population genetic structure of the riverine caddisfly Stenopsyche marmorata (Trichoptera:Stenopsychidae) from 4 adjacent catchments in northeastern Japan. We genotyped larval individuals (N = 532) from 30 sites at 8 polymorphic microsatellite loci. Fixation indices suggested low levels of genetic differentiation among populations (global F-ST = 0.062, p < 0.01), and significant isolation-by-distance (IBD) indicated populations were in drift-migration equilibrium. Bayesian clustering separated S. marmorata into distinct upland (> 250 m asl) and lowland populations, with different F-ST values (upland F-ST = 0.048, p < 0.01; lowland F-ST = 0.029, p < 0.01) and significant IBD only among upland populations. Allele frequencies were significantly positively autocorrelated (Moran's I > 0, p < 0.05) at distances up to 18 km along streams and up to 12 km across terrestrial habitat. These values were similar to directly observed flight distance in a single generation for this species in the field. We conclude that the multiple-method approach revealed: 1) unexpected population subdivision between upland and lowland areas that may result from local adaptation, differences in phenology, and historical colonization by multiple lineages; and 2) fine-scale estimates of dispersal that match direct observations of flight and suggest gene flow is more pronounced along water
  • 高瀬 陽彦, 糠澤 桂, 風間 聡, 渡辺 幸三
    土木学会論文集B1(水工学) 70 4 I_1297 - I_1302 Japan Society of Civil Engineers 2014年 [査読有り]
     
    This study quantitatively evaluated Habitat Suitability Index (HSI) and species diversity of benthic invertebrates using a distributed hydro-thermal model and observed benthic samples from 45 localities in the Natori River basin, Northeast of Japan. We applied probability density function and histogram analysis to the Suitability Index (SI) model analysis. To evaluate basin-scaled habitat values of invertebrate families, we used the index Weight Usable Ratio (WUR). From the viewpoint of repeatability in the multiple modeling manners, Diptera had the highest WUR in basin. We estimated spatial distribution of Shannon-Weiner diversity index based on the HSIs to evaluate species diversity throughout the basin. Results in the both applications showed that regions found in the top 80% of the diversity index were allocated from the upper to the middle stream.
  • 三浦 郁修, 渡部 徹, 渡辺 幸三, 福士 謙介
    土木学会論文集G(環境) 70 7 III_295 - III_304 公益社団法人 土木学会 2014年 
    本研究では,家庭内二次感染を考慮したノロウイルス感染症伝播モデルの構築,対象地域でのモデルシミュレーションの実行,およびそのシミュレーション結果と疫学データの比較を通じた本モデルの有用性を検討した.その結果,流行のピークまでに要する時間は,考察した4種類の不確定性が高いパラメーターのうち,NVを含む食品の摂取期間に敏感に反応することがわかった.加えて,家族構成に応じて,家庭内二次感染リスクは一次感染リスクよりも大きくなることが定量的に示された.特に,総員4人以上で幼児が存在する家庭では家庭内二次感染リスクは一次感染リスクの10倍以上になった.最後に,上記のパラメーターに対するピーク時点の反応を利用し,疫学データとの比較を通じた実際の流行に対するアプローチの一例を示した.
  • Kozo Watanabe, So Kazama, Tatsuo Omura, Michael T Monaghan
    PloS one 9 3 e93055  2014年 [査読有り]
     研究論文(学術雑誌) 
    A central question linking ecology with evolutionary biology is how environmental heterogeneity can drive adaptive genetic divergence among populations. We examined adaptive divergence of four stream insects from six adjacent catchments in Japan by combining field measures of habitat and resource components with genome scans of non-neutral Amplified Fragment Length Polymorphism (AFLP) loci. Neutral genetic variation was used to measure gene flow and non-neutral genetic variation was used to test for adaptive divergence. We identified the environmental characteristics contributing to divergence by comparing genetic distances at non-neutral loci between sites with Euclidean distances for each of 15 environmental variables. Comparisons were made using partial Mantel tests to control for geographic distance. In all four species, we found strong evidence for non-neutral divergence along environmental gradients at between 6 and 21 loci per species. The relative contribution of these environmental variables to each species' ecological niche was quantified as the specialization index, S, based on ecological data. In each species, the variable most significantly correlated with genetic distance at non-neutral loci was the same variable along which each species was most narrowly distributed (i.e., highest S). These were gradients of elevation (two species), chlorophyll-a, and ammonia-nitrogen. This adaptive divergence occurred in the face of ongoing gene flow (Fst = 0.01-0.04), indicating that selection was strong enough to overcome homogenization at the landscape scale. Our results suggest that adaptive divergence is pronounced, occurs along different environmental gradients for different species, and may consistently occur along the narrowest components of species' niche.
  • 八重樫咲子, 渡辺幸三, 大村達夫
    環境工学研究論文集 50 III.489-III.494  2013年11月 [査読有り]
  • Scharnweber K, Watanabe K, Syväranta J, Wanke T, Monaghan MT, Mehner T
    BMC evolutionary biology 13 132  2013年06月 [査読有り]
  • Akihiko Takase, Kei Nukazawa, So Kazama, Kozo Watanabe
    PROCEEDINGS OF THE 35TH IAHR WORLD CONGRESS, VOLS I AND II 2611 - 2617 2013年 [査読有り]
     研究論文(国際会議プロシーディングス) 
    We evaluated spatial variations of habitat suitability of nine aquatic insects in the Natori River basin, Northeast Japan quantitatively combining dual approaches of using Habitat Suitability Index (HSI) model analysis and hydrothermal simulation model. We also developed a new index of the Weighted Usable Ratio (WUR) for evaluating the overall habitat suitability throughout the catchment for each species. The results of spatial distributions of HSI showed species-specific patterns such as wide distribution of digit grids with high HSI throughout the catchment in habitat generalists (for example, Baetis, WUR=0.55) while the constrained distribution in habitat specialists (for example, Limnocentropus insolitus, WUR=0.06). Overall, the spatial variation of HSI showed good consistency with the empirical habitat distributions, supporting the accuracy of our model approach.
  • 高橋 真司, 竹門 康弘, 大村 達夫, 渡辺 幸三
    土木学会論文集G(環境) 69 7 III_547 - III_555 公益社団法人 土木学会 2013年 
    ダム下流河川区間は, ダム湖で生産されたプランクトンなどの微粒状有機物(FPOM)を大量に受容しているため, ダム湖に依存した有機物環境が形成されているが, ワンドやタマリなどの止水性のハビタットは, このダムの影響が軽減されている可能性がある. 本研究はダム下流域の流水域および止水域に着目し, FPOMの起源の違いを明らかにすることを目的とした. 起源物質はダム湖有機物, 河川内付着生物層, 落ち葉の3種とした. 解析の結果, 止水域の浮遊性FPOMへのダム湖有機物の寄与率は, 流水域より有意に低い値を示した. また, 止水域は付着生物層及び落ち葉の現存量が流水域より多かった. したがって, 止水域は付着生物層及び落ち葉由来のFPOMが多く供給され, ダムに依存しにくい有機物環境が形成されていることが明らかとなった.
  • 八重樫 咲子, 渡辺 幸三, 大村 達夫
    土木学会論文集G(環境) 69 7 III_489 - III_494 公益社団法人 土木学会 2013年 
    河川水生昆虫ヒゲナガカワトビケラ(Stenopsyche marmorata)の生息環境の特性が遺伝的多様性に与える環境選択の影響を評価した. 宮城県中南部地域4水系30地点と本州6地点で採取したヒゲナガカワトビケラをマイクロサテライト8遺伝子座でシェノタイピングした. 遺伝子座ごとに進化シミュレーションに基づく中立進化を帰無仮説とした仮説検定を行い, 3つの環境選遺伝子座を同定した. これら3つの環境選択遺伝子座における平均的な遺伝的多様性と環境指標の偏相関分析を行った結果, ヒゲナガカワトビケラ集団内の平均対立遺伝子数は餌資源の量(SS, FPOM, 付着生物膜のクロロフィルa濃度, FBOM)と河床環境の多様さ(石礫の粒径の分散, 堆積土砂の均等係数)と有為な正の偏相関を示した. この結果は, 餌が豊富で多彩な河床環境を有する地域では, 適応度の低い対立遺伝子・遺伝子型が定着し, 集団内の遺伝的多様性を高めていることを示唆する. ただし, BODと平均対立遺伝子数は有為な負の相関を示していることから, 水質の悪化は遺伝的多様性の悪化を引き起こす可能性も考えられる. 本研究の結果は, 環境選択遺伝子座を用いることで, 人為的河川環境の改変が水生生物の遺伝的多様性に与える影響を評価できる可能性を示す.
  • 糠澤 桂, 風間 聡, 渡辺 幸三
    土木学会論文集B1(水工学) 69 4 I_1303 - I_1308 Japan Society of Civil Engineers 2013年 [査読有り]
     
    In accordance with a most recent report in discipline "landscape genetics", simulation studies to predict spatial genetic variation are urgently required. We evaluated relationships between genetic diversities of caddisfly Hydropsyche orientalis and species diversity calculated from Habitat Suitability Index (HSI) of aquatic animals and discussed outliers in the correlation diagrams in the Natori River basin located at the middle of Miyagi prefecture. Omitting two significant outliers, we developed spatial genetic diversity distribution maps on the basis of linear regression models in the correlation diagrams. At the catchment scale, the longitudinal distribution of genetic diversity had high peak in the middle stream. The result is identical with the observed pattern of genetic diversity for the species. The prediction has advantages which can be applied to future planning in respect of dam removal, urban planning, and zoning in view of genetic diversity.
  • 高瀬 陽彦, 糠澤 桂, 風間 聡, 渡辺 幸三
    土木学会論文集B1(水工学) 69 4 I_1255 - I_1260 公益社団法人 土木学会 2013年 
    We evaluated spatial variations of habitat suitability of nine aquatic insects in the Natori River basin, Northeast Japan quantitatively combining dual approaches of using Habitat Suitability Index (HSI) model analysis and hydrothermal simulation model. We also developed a new index of the Weighted Usable Ratio (WUR) for evaluating the overall habitat suitability throughout the catchment for each species. The results of spatial distributions of HSI showed species-specific patterns such as wide distribution of digit grids with high HSI throughout the catchment in habitat generalists (e.g., Baetis, WUR=0.55) while the constrained distribution in habitat specialists (e.g., Limnocentropus insolitus, WUR=0.06). Overall, the spatial variation of HSI showed good consistency with the empirical habitat distributions, supporting the accuracy of our model approach.
  • 八重樫咲子, 渡辺幸三, 高橋真司, 永峯賢人, 大村達夫
    環境工学研究論文集 49 III.611-III.616  2012年11月 [査読有り]
  • 高橋真司, 渡辺幸三, 竹門康弘, 大村達夫
    応用生態工学 15 1 121 - 130 2012年07月 [査読有り]
  • 寺田 匡徳, 渡辺 幸三, BERTOLDI W., GURNELL A.M., TOCKNER K., 竹門 康弘, 角 哲也
    京都大学防災研究所年報 56 691 - 698 京都大学防災研究所 2012年 
    Biodiversity of lentic habitats in river channels generally depends on a frequency of connection with channels and the time since the habitat was born. The Tagliamento River in the north Italy has a steep basin with high sediment supply and thus its middle reaches form braided channels changing frequently with flow fluctuations. To understand relations of species diversity of aquatic animal communities to age of lentic habitats, the temporal dynamics of the habitats in two reaches of the river were recorded by fixed cameras installed on the cliff tops beside the reaches. A total of 89 habitats were chosen to collect aquatic animals and to measure environment factors in April to May, 2011. This paper revealed that lentic species increase with the age of habitats while lotic species decrease with the age. Considering with specificity of habitat preference, we discussed on the age and longevity of the lentic habitats required for maximize biodiversity of habitats scale and reach scale.
  • Shinji Takahashi, Kozo Watanabe, Yasuhiro Takemon, Tatsuo Omura
    Ecology and Civil Engineering 15 1 121 - 130 2012年 [査読有り]
     研究論文(学術雑誌) 
    Spatial structures of 7 types of aquatic habitat at the reach scale were delineated using a high precision Global Position System (GPS) in 3 dam-impacted and 6 reference riverrine reaches in Miyagi Prefecture, Japan. Taxonomic and functional compositions of quantitative benthic invertebrate samples were also investigated. Out of the three dams, two indicated decreased levels of habitat diversity indexes (S, H', a, and E) at the outlet reaches due to reduced sediment supply and reduced hydraulic variation through dam-operation but one dam connected to meandering outlet reach did not. Percentage of total area of lentic habitats (i. e., backwater and isolated pool) at the dam-impacted reaches (mean= 1.5%) was significantly lower than reference reaches (mean=5.5%). The taxon richness, abundance of swimmers, predators, attachers and crawlers increased with the percentage of lentic habitat area (P< 0.05, n=9), which suggests that lentic habitats contribute to maintain species diversity and the functional groups at the reach scale. Our data indicated a high application potential of the GPS-based evaluation of habitat structure for biodiversity conservation in rivers.
  • 寺田 匡徳, 渡辺 幸三, BERTOLDI W., GURNELL A.M., TOCKNER K., 竹門 康弘, 角 哲也
    京都大学防災研究所年報 56 691 - 698 京都大学防災研究所 2012年 
    Biodiversity of lentic habitats in river channels generally depends on a frequency of connection with channels and the time since the habitat was born. The Tagliamento River in the north Italy has a steep basin with high sediment supply and thus its middle reaches form braided channels changing frequently with flow fluctuations. To understand relations of species diversity of aquatic animal communities to age of lentic habitats, the temporal dynamics of the habitats in two reaches of the river were recorded by fixed cameras installed on the cliff tops beside the reaches. A total of 89 habitats were chosen to collect aquatic animals and to measure environment factors in April to May, 2011. This paper revealed that lentic species increase with the age of habitats while lotic species decrease with the age. Considering with specificity of habitat preference, we discussed on the age and longevity of the lentic habitats required for maximize biodiversity of habitats scale and reach scale.
  • 八重樫 咲子, 渡辺 幸三, 高橋 真司, 永峯 賢人, 大村 達夫
    土木学会論文集G(環境) 68 7 III_611 - III_616 公益社団法人 土木学会 2012年 
    河川水生昆虫モンカゲロウ(Ephemera strigata)を対象生物として,河川内に見られる瀬,淵,ワンド等のハビタット間の環境異質性が,適応放散で形成される遺伝的多様性に与える影響を評価した.宮城県名取川水系の11地点の7区分のハビタットから採取した220個体をAFLP法で319遺伝子座をジェノタイピングし,その中から9の環境選択遺伝子座を遺伝シミュレーションで検索した.また,調査地点のハビタット地形形状を高精度GPSのProMark3を用いてマッピングした.9つの環境選択遺伝子座とハビタットの関係を解析した結果,2つの環境選択遺伝子座の対立遺伝子頻度と遺伝的多様性が地点内の止水性ハビタット(ワンド,タマリ,トロ)の面積割合と正の相関を示し,これら遺伝子座とハビタット構造の連関が推定された.この結果は,河川内において止水性ハビタットを保全する河川管理が,水生生物の遺伝的多様性の保全に繋がることを示唆している.
  • 糠澤 桂, 風間 聡, 渡辺 幸三
    土木学会論文集G(環境) 68 7 III_603 - III_610 公益社団法人 土木学会 2012年 
    宮城県名取川流域において,HSI(Habitat Suitability Index)から算出された種多様性(HSI種多様性)と2006年における現地調査により得られた4種水生昆虫の遺伝的多様性の関係性を評価した.HSIモデルは地理データ(土地利用,勾配など),分布型流出モデルから算出した水理情報を基に6種水生生物に関して構築したものを使用した.結果として,ウルマーシマトビケラの3種遺伝的多様性指標がHSI種多様性と有意な正の相関を示した.HSI種多様性が高い場所においては水生生物の生息ポテンシャルが高いと考えられる.このため,対象種の移入・定着が容易になるに従い遺伝子流動性が高まり,結果として遺伝的多様性が増加したと推測される.
  • マイクロサテライトマーカーを用いたヒゲナガカワトビケラの流域内および流域間移動分散の評価
    八重樫咲子, 渡辺幸三, 大村達夫
    土木学会論文集G(環境) 67 7 III_99 - III_106 2011年11月 [査読有り]
     研究論文(学術雑誌)
  • 八重樫咲子, 渡辺幸三, 大村達夫
    環境工学研究論文集 48 III.99-III.106  2011年11月 [査読有り]
  • K. Nukazawa, S. Kazama, K. Watanabe, J. Kang
    WIT Transactions on Ecology and the Environment 146 263 - 274 2011年 [査読有り]
     研究論文(学術雑誌) 
    In order to assess the impacts of sabo dam (check dam) construction, species diversity of benthic faunal communities and genetic diversity of caddisfly Stenopsyche marmorata were investigated using microsatellite analysis along the Oisawa River, Japan. The Oisawa River is fragmented by two slit sabo dams and one unslit sabo dam. Over the slit dams, Shannon-Weiner diversity indices and number of taxa ranged from 0.90 to 1.02 and 13 to 15 respectively in the upstream region, and also from 0.98 to 1.18 and 13 to 20 respectively in the downstream region. Through microsatellite analysis of S. marmorata, we found two selective alleles, which show clear genetic differentiation among three upstream sites and four downstream sites in the study area. Longitudinal change of mean heterozigosities Ho showed a decreasing pattern of genetic diversity in the downstream site (=0.486 - 0.678), and it showed the highest diversity at the highest upstream site, which receives no effect of the unslit dam. Differences of community's species compositions between sites were correlated to geographical distances whereas genetic distances between sites were not correlated to geographical distances, suggesting that species compositions of the communities were determined through the process of species adaptation to the local environment. We concluded that increments of species diversity at the inlet reaches of the slit dam were caused by the recovery of habitats, and by the continuousness of the stream which allows the flowing of particulate organic matters and sediments to the downstream area. In part of some loci, genetic selection might occur by the different velocities caused by sabo dam constructions, because S marmorata (filter-feeder) has the habit of constructing nets to filter and collect fine particulate organic matter (FPOM) from water flow. © 2011 WIT Press.
  • Species diversity of benthic faunal communities along a mountain stream fragmented by slit and unslit dam
    Kei Nukazawa, So Kazama, Kozo Watanabe
    Proceedings of the 5th conference of Asia Pasific Association of Hydrology and Water Resources(APHW) 48 - 55 2010年11月 [査読有り]
     研究論文(国際会議プロシーディングス)
  • Kozo Watanabe, Michael T. Monaghan, Yasuhiro Takemon, Tatsuo Omura
    AQUATIC CONSERVATION-MARINE AND FRESHWATER ECOSYSTEMS 20 5 574 - 579 2010年07月 [査読有り]
     研究論文(学術雑誌) 
    1. The dispersal ability of species and the geographic scale of habitat fragmentation both may influence the extent of gene flow between fragments, but their interactions have rarely been tested, particularly among co-occurring species. 2. Population genetic structures of three species of aquatic insect were compared in streams fragmented by reservoirs and in unfragmented streams in north-eastern Japan, using 52, 37, and 58 RAPD markers. The three species studied included a strong disperser Cincticostella elongatula (Ephemeroptera: Ephemerellidae), an intermediate disperser Stenopsyche marmorata (Trichoptera: Stenopsychidae), and a weak disperser Hydropsyche orientalis (Trichoptera: Hydropsychidae). 3. The patterns of genetic isolation by distance (IBD) supported a priori hypotheses of dispersal ability. The strong disperser (C. elongatula) exhibited significant IBD only at the largest spatial scale studied (among drainages, r = 0.50, P < 0.01). The intermediate disperser (S. marmorata) showed IBD both within (r = 0.22, P < 0.01) and among (r = 0.45, P < 0.01) drainages. The weak disperser (H. orientalis) did not exhibit significant IBD at any scale. 4. Pairwise genetic differentiation (theta) indicated that neither the weak disperser nor the strong disperser were genetically differentiated above and below reservoirs when compared with reference sites. This was in contrast to previous results for S. marmorata, for which subpopulations were genetically fragmented across larger (>4.1 km), but not smaller (<2.9 km) reservoirs. 5. We suggest that intermediate dispersers, i.e. those at equilibrium between migration and genetic drift within drainages, are more likely to be affected by fragmentation than either strong or weak dispersers. Intermediate dispersers could therefore be used as indicator species in studies aimed at detecting the effects of distance between habitat fragments (e. g. reservoir size) for conservation planning. Copyright (C) 2010 John Wiley & Sons, Ltd.
  • 糠澤桂, 風間聡, 渡辺幸三
    水工学論文集(CD-ROM) 54 ROMBUNNO.215  2010年02月 [査読有り]
  • 高橋真司, 五十嵐夏奈, 伊藤歩, 渡辺幸三, 相澤治郎, 大村達夫, 海田輝之
    環境工学研究論文集 46 1 - 8 2009年11月 [査読有り]
  • 鈴木祥一, 渡辺幸三, 八重樫咲子, 大村達夫
    環境工学研究論文集 46 529 - 536 2009年11月 [査読有り]
  • L. G. Abercrombie, C. M. Anderson, B. G. Baldwin, I. C. Bang, R. Beldade, G. Bernardi, A. Boubou, A. Branca, F. Bretagnolle, M. W. Bruford, A. Buonamici, R. K. Burnett, D. Canal, H. Cardenas, C. Caullet, S. Y. Chen, Y. J. Chun, C. Cossu, C. F. Crane, S. Cros-Arteil, R. Cudney-Bueno, R. Danti, J. A. Davila, G. Della Rocca, S. Dobata, L. D. Dunkle, S. Dupas, N. Faure, M. E. Ferrero, B. Fumanal, G. Gigot, I. Gonzalez, S. B. Goodwin, D. Groth, B. D. Hardesty, E. Hasegawa, E. A. Hoffman, M. L. Hou, A. F. J. Jamsari, H. J. Ji, D. H. Johnson, L. Joseph, F. Justy, E. J. Kang, B. Kaufmann, K. S. Kim, W. J. Kim, A. V. Koehler, B. Laitung, P. Latch, Y. D. Liu, M. B. Manjerovic, E. Martel, S. S. Metcalfe, J. N. Miller, J. J. Midgley, A. Migeon, A. J. Moore, W. L. Moore, V. R. F. Morris, M. Navajas, D. Navia, M. C. Neel, P. J. G. de Nova, I. Olivieri, T. Omura, A. S. Othman, J. Oudot-Canaff, D. R. Panthee, C. L. Parkinson, I. Patimah, C. A. Perez-Galindo, J. B. Pettengill, S. Pfautsch, F. Piola, J. Potti, R. Poulin, P. T. Raimondi, T. A. Rinehart, A. Ruzainah, S. K. Sarver, B. E. Scheffler, A. R. R. Schneider, J. F. Silvain, M. N. Siti Azizah, Y. P. Springer, C. N. Stewart, W. Sun, R. Tiedemann, K. Tsuji, R. N. Trigiano, G. G. Vendramin, P. A. Wadl, L. Wang, X. Wang, K. Watanabe, J. M. Waterman, W. W. Weisser, D. A. Westcott, K. R. Wiesner, X. F. Xu, S. Yaegashi, J. S. Yuan
    MOLECULAR ECOLOGY RESOURCES 9 5 1375 - 1379 2009年09月 [査読有り]
     研究論文(学術雑誌) 
    This article documents the addition of 283 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Agalinis acuta; Ambrosia artemisiifolia; Berula erecta; Casuarius casuarius; Cercospora zeae-maydis; Chorthippus parallelus; Conyza canadensis; Cotesia sesamiae; Epinephelus acanthistius; Ficedula hypoleuca; Grindelia hirsutula; Guadua angustifolia; Leucadendron rubrum; Maritrema novaezealandensis; Meretrix meretrix; Nilaparvata lugens; Oxyeleotris marmoratus; Phoxinus neogaeus; Pristomyrmex punctatus; Pseudobagrus brevicorpus; Seiridium cardinale; Stenopsyche marmorata; Tetranychus evansi and Xerus inauris. These loci were cross-tested on the following species: Agalinis decemloba; Agalinis tenella; Agalinis obtusifolia; Agalinis setacea; Agalinis skinneriana; Cercospora zeina; Cercospora kikuchii; Cercospora sorghi; Mycosphaerella graminicola; Setosphaeria turcica; Magnaporthe oryzae; Cotesia flavipes; Cotesia marginiventris; Grindelia Xpaludosa; Grindelia chiloensis; Grindelia fastigiata; Grindelia lanceolata; Grindelia squarrosa; Leucadendron coniferum; Leucadendron salicifolium; Leucadendron tinctum; Leucadendron meridianum; Laodelphax striatellus; Sogatella furcifera; Phoxinus eos; Phoxinus rigidus; Phoxinus brevispinosus; Phoxinus bicolor; Tetranychus urticae; Tetranychus turkestani; Tetranychus ludeni; Tetranychus neocaledonicus; Tetranychus amicus; Amphitetranychus viennensis; Eotetranychus rubiphilus; Eotetranychus tiliarium; Oligonychus perseae; Panonychus citri; Bryobia rubrioculus; Schizonobia bundi; Petrobia harti; Xerus princeps; Spermophilus tridecemlineatus and Sciurus carolinensis.
  • 渡辺 幸三, 八重樫 咲子, 菊池 裕二, 竹門 康弘, 風間 聡, 大村 達夫
    水環境学会誌 = Journal of Japan Society on Water Environment 32 5 253 - 258 社団法人日本水環境学会 2009年05月 
    Population connectivity of aquatic organisms is an important factor for sustaining the robustness of metapopulation in a basin-scale as well as for interpreting the properties of respective local populations. We examined the genetic structure of 30 Stenopsyche marmorata (Tricoptera) local populations in 4 catchments in South-Central Miyagi Prefecture, Japan using AFLP markers, and evaluated their dispersal pattern. We constructed a dendrogram using q, and found that 7 populations in headwater were isolated from another area in the basins. Although previous studies on S. marmorata adult flight within streams reported most of the females fly upstream along a watercourse after mating, our results indicated high possibility of non-directional adult dispersal due to wind. The results also suggested a strong potential for DNA polymorphic analysis to enhance understanding of the population connectivity and dispersal patterns of aquatic organisms in a basin scale.
  • 真野 明, 大村 達夫, 有働 恵子, 渡辺 幸三, 白鳥 喜之, 小竹 翔太
    財団法人建設工学研究振興会年報 44 44 51 - 52 東北大学 2009年04月
  • Yoshiyuki Shirotori, Kozo Watanabe, Keiko Udo, Akira Mano
    Advances in Geosciences: Volume 11: Hydrological Science (HS) 223 - 235 2009年01月 [査読有り]
     論文集(書籍)内論文 
    On the upstream of Atago weir, Hirose River, Japan, the sedimentation phenomenon is complex due to the coexistence of the weir and channel bend. Moreover, fine sediment accumulates on the river bed notably. From the observed results, it is found that silt is the major component in the flood water and accumulates significantly in the discharge increasing stage by the backwater of the weir. From the theoretical computation considering the settling and resuspension of the suspended sediment, the cohesion of fine sediment is an important factor of the net deposition process.
  • Yoshiyuki Shirotori, Kozo Watanabe, Keiko Udo, Akira Mano
    ADVANCES IN WATER RESOURCES AND HYDRAULIC ENGINEERING, VOLS 1-6 815 - 820 2009年 [査読有り]
     研究論文(国際会議プロシーディングス) 
    On the upstream of Atago weir, Hirose River, Japan, the sedimentation phenomenon is complex due to the coexistence of the weir and channel bend. Moreover, fine sediment accumulates on the river bed notably not only the floodplain. In this study, we conducted field observation and numerical computation. From the observation results, we found that fine sediment is the major component in the flood water and accumulates significantly close to the inner bank (silt and clay= 55% in the maximum). In the numerical computation, we calculated the flow using finite volume method with unstructured grid. The suspended-sediment transport was calculated by the advection-diffusion equation considering settling and resuspension. By considering the weir and cohesivity of the fine sediment, we reproduced the settling-resuspension characteristics of the fine sediment. From this calculation result, the deposition and erosion region was indicated.
  • Kozo Watanabe, Michael T. Monaghan, Tatsuo Omura
    AQUATIC SCIENCES 70 4 377 - 387 2008年12月 [査読有り]
     研究論文(学術雑誌) 
    Small local populations may have low levels of genetic diversity, although widespread gene flow may counteract genetic drift and maintain high local diversity. At a larger spatial scale, a relationship between population size and genetic diversity could have important effects on the longitudinal genetic patterns in riverine corridors. We examined the genetic structure of 15 subpopulations of the caddisfly Hydropsyche orientalis in four rivers within the Natori River system in Japan using 78 polymorphic RAPD loci. Six subpopulations were fragmented by reservoirs and thus may be smaller, genetically isolated, or both. Pairwise F (ST) values were generally high throughout the study, and a higher mean value across the reservoirs (mean=0.219) relative to unfragmented streams 0.157) indicated reduced gene flow. Genetic diversity was not consequently reduced in these subpopulations; however, genetic diversity was positively correlated with larval density at all sites (percentage of polymorphic loci, %P = 46.3-59.1; expected heterozygosity H (exp) = 0.163-0.225). The longitudinal distribution of genetic diversity exhibited a unimodal pattern, with a peak in middle reaches. Correlation with larval density was a significant factor, although the presence of cryptic species as well as unimodally distributed environmental variables (e.g., habitat heterogeneity) provide alternative hypotheses. We suggest that studies examining longitudinal patterns of genetic diversity will provide a better understanding of the principal mechanisms that create and maintain biodiversity in rivers and streams.
  • Kozo Watanabe, Michael T. Monaghan, Yasuhiro Takemon, Tatsuo Omura
    SCIENCE OF THE TOTAL ENVIRONMENT 394 1 57 - 67 2008年05月 [査読有り]
     研究論文(学術雑誌) 
    Analysis of carbon (delta C-13) and nitrogen (delta N-15) stable isotopes provides an increasingly important means of understanding the complex trophic structure of macroinvertebrate communities in streams. We coupled a stable isotope approach with a contaminant analysis of six metals (Pb, Ag, Zn, Hg, Cu, As) to trace the accumulation and dilution of metals from an abandoned mine across trophic levels of the benthic community in Ginzan Creek, Japan. The delta N-15 signature increased with trophic level, with mean increases of 4.70%. from producers to primary consumers and 3.06%. from primary to secondary consumers. Tissue Pb and Ag concentrations were negatively correlated with delta N-15, indicating biodilution of both metals through the food web. Although macroinvertebrate taxon body mass was negatively correlated with tissue metal concentration at several sites, it did not increase with trophic level (as delta N-15) in any of the sites, suggesting that changes in body mass were not the cause of biodilution. Our findings suggest invertebrates at higher trophic levels may exhibit increasingly efficient excretion of metals. Autotrophic epilithon (mean delta C-13 =-21.3%.) had a much higher concentration of mined metals than did riparian vegetation (mean delta C-13 = -29.3%.); nonetheless, a carbon-mixing model indicated that taxa. feeding on autochthonous carbon sources did not accumulate more metal than allochthonous feeders. It is likely that the notably high metal concentration of allochthonous FPOM plays an important role in the trophic transfer of metals. Our data suggest the strong potential for stable isotope analysis to enhance our understanding of metal transfer through stream macroinvertebrate food webs. (c) 2008 Elsevier B.V. All rights reserved.
  • 渡辺幸三, 白鳥喜之, 有働恵子, 真野明, 大村達夫
    水工学論文集(CD-ROM) 52 ROMBUNNO.194  2008年02月 [査読有り]
  • 浜本洋, 風間聡, 渡辺幸三, 沢本正樹, 大村達夫
    水工学論文集(CD-ROM) 52 ROMBUNNO.196  2008年02月 [査読有り]
  • 渡辺 幸三, 菊池 祐二, 風間 聡, 大村 達夫
    水環境学会誌 = Journal of Japan Society on Water Environment 31 1 31 - 37 公益社団法人 日本水環境学会 2008年01月 
    The genetic diversity of Stenopsyche marmorata was investigated in three spatial hierarchies, among catchments, among reaches within catchments, and among individuals within reaches, by AFLP analysis of 306 individuals in 12 reaches in 3 catchments in Eastern Japan. The analysis of molecular variance revealed that the diversity within reaches accounted for the highest percentage (86%) of the total genetic variation in the three hierarchies. The genetic diversity between reaches increased with geographical distance between reaches on a small spatial scale (=2-74km); however, it did not increase on a large spatial scale (=74-450km). The level of gene flow among adjacent catchments (=55-74km) was lower than that between reaches within catchments (=2-19km). The genetic diversity within reaches (as the percentage of polymorphic loci and expected heterozygosity) positively correlated with altitude, suggesting that altitude is an environmental factor in determining the local population size of S. marmorata in each reach.
  • Kozo Watanabe, Tatsuo Omura
    WATER SCIENCE AND TECHNOLOGY 58 3 503 - 512 2008年 [査読有り]
     研究論文(学術雑誌) 
    The trophic structure of a macro invertebrate community was investigated using carbon and nitrogen stable isotopes analysis (delta C-13 and delta N-15) at three longitudinal sites along the main channel of the Hirose River, Japan, and at an outlet site of the tributary reservoir. Along the main channel, primal food supply gradually changed from allochthonous to autochthonous source. The percentage of autochthonous origin of the macroinvertebrate community calculated by a carbon-mixing model ( = 38-83%) increased with that of suspended fine particulate organic matter (FPOM = 21-67%), a main resource for filtering-collectors that dominated the communities. The lowest percentage of autochthonous in the lake outlet community ( = 21%) was a result of the notably low percentage autochthonous of FPOM due to the decomposition of allochthonous coarse particulate organic matter (e.g., leaf) strained in the reservoir. Predators had higher mean delta N-15 than non-predators in three sites. The average enrichments of delta N-15 signature per trophic level for all sites were 3.82 parts per thousand from producers to first consumers and 1.24 parts per thousand from first to second consumers. Our data suggest the strong potential for stable isotope analysis to enhance our understanding of the trophic structure of stream macroinvertebrate community.
  • 渡辺幸三, 草野光, 大村達夫
    環境工学研究論文集 44 83 - 92 2007年11月 [査読有り]
  • 菊池祐二, 渡辺幸三, 風間聡, 大村達夫, 沢本正樹
    環境工学研究論文集 44 99 - 106 2007年11月 [査読有り]
  • 城戸和寿, 後藤勝洋, 佐合純造, 大村達夫, 渡辺幸三
    リバーフロント研究所報告 18 159 - 166 2007年09月
  • 渡辺幸三, 大村達夫
    土木学会論文集 G 63 2 93 - 101 2007年07月 [査読有り]
  • Kozo Watanabe, Tatsuo Omura
    BIOLOGICAL CONSERVATION 136 2 203 - 211 2007年04月 [査読有り]
     研究論文(学術雑誌) 
    Reservoirs have the potential to block the gene flow of stream macroinvertebrates along a Received 27 February 2006 channel, which takes place via larval drift and adult flight, resulting in genetic differentiation Received in revised form above and below the reservoirs. Gene flow across the reservoirs may be strongly obstructed if 15 November 2006 the area of standing water is larger. Using random amplified polymorphic DNA markers, we Available online 17 January 2007 investigated the genetic structure of Stenopsyche marmorata (Stenopsychidae: Trichoptera) populations found above and below the reservoirs, and the reference stream of six reservoirs Keywords: with small to large water surface area ranging from 0.12 km(2) to 6.00 km(2). As a result, the two largest reservoirs with a standing water area larger than 3.27 km(2) showed significant differ flow ences in pairwise 0 between fragmented and reference streams, whereas the other four res fragmentation ervoirs with a standing water area smaller than 1.64 km(2) showed insignificant differences. Genetic diversity The genetic differentiations in the two largest reservoirs did not result in the reduction of Population size genetic diversities in the fragments. Based on the significant correlation between relative population size and mean expected heterozygosity, we concluded that local genetic diversities were constrained in smaller populations due to the effect of genetic drift. (C) 2006 Elsevier Ltd. All rights reserved.
  • 白鳥喜之, 渡辺幸三, 有働恵子, 真野明
    東北地域災害科学研究 43 199 - 204 2007年03月 [査読有り]
  • 広瀬川愛宕堰上流における堆積環境の実態解明
    白鳥喜之, 渡辺幸三, 有働恵子, 真野明
    土木学会東北支部技術研究発表会 44 Ⅱ-29  2007年 研究論文(その他学術会議資料等)
  • 渡辺幸三, 草野光, 大村達夫
    土木学会論文集 G 63 3 186-194 (J-STAGE)  2007年 [査読有り]
  • 渡辺 幸三, 大村 達夫
    土木学会論文集 62 1 94 - 104 公益社団法人 土木学会 2006年04月 
    ダム湖は河川水生昆虫の幼虫と成虫の移動を阻害し,ダム上下流間の遺伝的分化やそれに伴う遺伝的多様性の低下を引き起こす恐れがある.本研究は湛水面積が異なる複数のダム湖周辺でヒゲナガカワトビケラ,ウルマーシマトビケラ,クロマダラカゲロウの3種の水生昆虫地域集団のRAPD解析を行った.解析の結果,ヒゲナガカワトビケラの遺伝的分化は6つのダム湖のうち湛水面積が 3.27 km2 以上の2つの大きなダム湖で遺伝的に分化していたが,ウルマーシマトビケラは湛水面積が小さい場合でも分化することがあった.また,ウルマーシマトビケラの遺伝的多様性の低下要因として,集団サイズの低下とダムによる生息地分断化の2因子が働くが,残り2種は集団サイズの低下のみが主に働いていることが明らかになった.
  • 渡辺 幸三, 大村 達夫
    土木学会論文集 = Proceedings of JSCE 811 49 - 59 土木学会 2006年02月
  • 渡辺 幸三, 山本 直樹, 草野 光, 大村 達夫
    水環境学会誌 = Journal of Japan Society on Water Environment 28 12 737 - 744 日本水環境学会 2005年12月 
    Concentrations of Ag, Pb, and Hg in samples of aquatic insects and feeding sources such as algae and leaves were determined at four sites along the Ginzan River, Which receives drainage from a mined land. Nitrogen (δ15N) and carbon (δ13C) isotope analyses of the samples were carried out to assess whether feeding sources or the trophic level influenced metal accumulation in each faunal taxon. The individual dry mass was also measured to examine the effect of body size on metal accumulation. The relationship between metal concentrations and level of δ15N in fauna indicated biodilutions for Pb (3 sites) and Ag (1 site) through the food webs. This must be caused by high concentrations of metals in algae and fine particulate organic matter (FPOM) as the main feeding sources for harvivores and detorivores. The relative contribution of autochthonous and allochthonous energy sources to each taxon's biomass had no effect on the concentrations of Ag, Pb, and Hg in the fauna. The individual dry mass was negatively correlated with the concentrations of Ag (3 sites), Pb (1 site), and Hg (4 sites) in fauna.
  • K Watanabe, C Yoshimura, T Omura
    ECOLOGICAL MODELLING 189 3-4 396 - 412 2005年12月 [査読有り]
     研究論文(学術雑誌) 
    A macroinvertebrate community having been pre-assessed to have lower resilience against anthropogenic pulse-disturbance in river (e.g. muddy water from construction site) should be given intensive preservation efforts. Using stochastic population dynamics model with density-dependant and environmental fluctuation, a recovery prediction model for macroinvertebrates' total biomass following its decline due to pulse-stressors have been developed. In this recovery model, the inherent resilience was determined by three parameters: carrying capacity, specific growth rate and environmental fluctuation intensity. The parameters were estimated from the time-series data of the total biomass. Using the application of the recovery model for a hypothesized scenario, the recovery index (RI) and the ecological time loss (ETL) were calculated. Both RI and ETL can evaluate the recovery process of the total biomass after an anthropogenic pulse-disturbance. A case study was done in 70 communities in Tokyo using the indexes of both RI and ETL. Recovery processes were simulated by administering a virtual pulse stressor to decrease the total biomass to 8%. As a result, 80% among the total number of communities performed a higher resilience within 3 years of the ETL. RI revealed that geographically neighboring community possesses extra-high resilience. Multiple regression analysis also proved that ETL was significantly explained by five environmental variables: specific conductivity, width of low-water channels, catchment area, suspended solid and stream order. As the results implied, macroinvertebrate community can recover quickly in total biomass when supplied from non-damaged upstream reaches. The case study also demonstrated the high potentialities of RI and the ETL for impact assessments in the river ecosystems. (c) 2005 Elsevier B.V. All rights reserved.
  • 山本 直樹, 渡辺 幸三, 草野 光, 大村 達夫
    水環境学会誌 = Journal of Japan Society on Water Environment 28 6 385 - 392 日本水環境学会 2005年06月 
    The trophic structures of benthic faunal communities in a river are expected to respond to the relative amounts of autochthonous and allochthonous energy sources in the environment. Using isotopic analysis of δ13C, we investigated the percentage of autochthonous energy of benthic fauna at 3 sites longitudinally sited along the Hirose River, and at a site at the outlet of the Okura reservoir in a tributary. The relative trophic level of each taxon was also estimated from δ15N, and a biomass pyramid for each community was produced. As a result, the percentage of autochthonous energy of benthic faunal community formed a longitudinal distribution along the river, showing a high peak midstream with lower values both upperstream and downstream. This profile was similar to a longitudinal pattern of that of Fine Particulate Organic Matters (FPOM) in flowing water, a main resource for filtering-collectors that dominate these communities. At the Okura reservoir outlet, the percentage of autochthonous energy of the community was the lowest among the four sites, reflecting a low percentage of autochthonous energy in FROM due to the decomposition of allochthonous organic matter in standing water. The biomass pyramid for each community showed an energy peak in the middle trophic level.
  • 渡辺 幸三, 大村 達夫
    土木学会論文集 = Proceedings of JSCE 790 49 - 58 公益社団法人 土木学会 2005年05月 
    ダム湖は河川水生昆虫の幼虫のドリフトと成虫の飛行を遮断するため, ダム上下流地点間の遺伝的分化やそれに伴う各地点の遺伝的多様性の低下を引き起こす恐れがある. また, 成虫の飛行距離の観点から, 湛水面積が大きいダム湖ほど遺伝的分化が大きいことが予想される. 本研究は湛水面積が異なる6つのダム湖を対象に, ダム湖で分断された河川と隣接するコントロール河川に生息するヒゲナガカワトビケラ地域集団のRAPD解析を行った. 解析の結果, 6つのダム湖のうち, 湛水面積が3.27 km2以上の2つのダム湖において遺伝的分化が起きていることがわかった. また, 遺伝的多様性を低下させる要因として, ダムによる遺伝子流動の低下よりも, 各地点の集団サイズの低下がより強く影響していることが明らかになった.
  • 渡辺 幸三, 吉村 千洋, 小川原 享志, 大村 達夫
    土木学会論文集 = Proceedings of JSCE 748 67 - 79 公益社団法人 土木学会 2003年11月 
    本研究は河川底生動物への人為的インパクトの影響を予見的に評価する回復予測モデルを開発した. このモデルは底生動物のバイオマスの経年変化を記述する群集動態モデルがベースになっており, Pulse 型 (一時的) インパクトの影響を回復率と生態学的損失時間 (ELT) の2指標によって評価するモデルとなっている. このモデルを東京都の延べ70地点に適用し, バイオマスが0.08倍に低下するインパクト (土木工事) を仮想して回復予測を行った結果, ELTが1年以内の地点は延べ35地点 (50%) を占め, 底生動物が有する高い回復能力が確認された. また, 算出された回復率とELTの値を各地点の環境状態から考察したところ, これらが Pulse 型インパクトの影響評価指標として有効であることが示された.
  • 渡辺 幸三, 吉村 千洋, 小川原 享志, 大村 達夫
    土木学会論文集 = Proceedings of JSCE 734 734 99 - 110 土木学会 2003年05月
  • 小川原 享志, 渡辺 幸三, 吉村 千洋, 大村 達夫
    水環境学会誌 = Journal of Japan Society on Water Environment 26 4 223 - 229 日本水環境学会 2003年04月 
    It has been reported that several floras and faunas in rivers are genetically impaired by artificial structures such as dams and cities because of the fragmentation and the reduced heterogeneity of their habitats. However, the investigations on genetic diversities of Trichoptera in rivers have been few to date. In this study, therefore, the genetic investigation of Hydropsyche orientalis was conducted at 13 stations in the Natori River System in Miyagi Prefecture, Japan from Dec. 2000 to May 2001. The Okura and Kamafusa dams, and the Sendai urban area are located upstream and downstream of the rivers. The DNA polymorphisms of Hydropsyche orientalis collected at the 13 stations were analyzed with the appropriate primer, OPA-11, for calculating the genetic diversity index. The result of statistical analysis of the index showed a significantly higher level of genetic diversity of Hydropsyche orientalis in the natural area than in the areas around the dams. Moreover, the effect of urbanization on its genetic diversity was indicated based on the estimation of its migration from the results of the cluster analysis of the DNA polymorphisms.

書籍

  • Health in Ecological Perspectives in the Anthropocene
    Carvajal, T. M, H. T. Ho, L. F. T. Hernandez, K. M. Viacrusis, D. M. Amalin, K. Watanabe (担当:共著, 範囲:An Ecological Context towards Understanding Dengue Disease Dynamics in Urban Cities: a Case Study in Metropolitan Manila, Philippines)
    Springer 2018年11月 ISBN: 9789811325267 159

講演・口頭発表等

MISC

受賞

  • 2014年09月 土木学会 平成26年度地球環境優秀講演賞
     
    受賞者: 糠澤桂;風間聡;渡辺幸三
  • 2010年09月 日本水環境学会 日本水環境学会平成21年年間優秀論文賞(メタウォーター賞)
     
    受賞者: 渡辺幸三;八重樫咲子;竹門康弘;風間聡;大村達夫
  • 2009年06月 財)建設工学研究振興会 平成20年度建設工学研究奨励賞
     
    受賞者: 渡辺幸三
  • 2005年03月 東北大学 平成16年度東北大学総長賞
     
    受賞者: 渡辺幸三
  • 2004年10月 応用生態工学会 応用生態工学会第8回大会ポスター賞(選考委員会部門
     
    受賞者: 渡辺幸三
  • 2004年10月 応用生態工学会 応用生態工学会第8回大会ポスター賞(一般投票部門)
     
    受賞者: 渡辺幸三
  • 2004年09月 土木学会 土木学会第59回年次学術講演会優秀講演者
     
    受賞者: 渡辺幸三
  • 2004年05月 土木学会 平成15年度土木学会論文奨励賞
     
    受賞者: 渡辺幸三

共同研究・競争的資金等の研究課題

  • 蚊共生細菌ボルバキアによるデング熱の生態学的制御:安心・安価な新技術の提案
    日本学術振興会:科学研究費助成事業 国際共同研究加速基金(国際共同研究強化(B))
    研究期間 : 2019年10月 -2022年03月 
    代表者 : 渡辺 幸三, 糠澤 桂, 八重樫 咲子, ガンボア・メンデス マリベット・アリアナ
  • 気候変動下での暑熱障害と感染症による健康リスクの予測と統合的評価
    日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 福士 謙介, 渡部 徹, 渡辺 幸三
  • 定量メタバーコーディングによる迅速で正確な種多様性評価:群集と環境DNAへの適用
    日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 渡辺 幸三, 加藤 幹男, 竹門 康弘
  • ノロウイルス感染症制御を可能とする水インフラの実現
    日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2018年04月 -2022年03月 
    代表者 : 大村 達夫, 李 玉友, 片山 浩之, 渡部 徹, 渡辺 幸三
     
    本研究は、「ノロウイルス感染症制御を可能とする水インフラ」の実現を目指すものである。充実した水インフラが整備されている先進諸国であっても、ノロウイルス感染症は制御不可能な状況にある。これは、水インフラの整備が遅れている開発国において病原性の高いノロウイルスの遺伝系統が容易に発生するためと推測される。そこで本研究では、「水インフラ環境が異なる地域間でノロウイルスの進化速度が異なる」との仮説を立て、その実証を試みることを目的としている。 研究初年度である平成30年度は、マウスノロウイルスを用いた精密膜ろ過及び消毒処理による環境選択実験により、精密膜ろ過により除去されにくいマウスノロウイルスの遺伝系統と、消毒剤耐性を有するマウスノロウイルスの遺伝系統を取得すること、及び下水・汚水由来のノロウイルス遺伝子取得を目的とした実験を行った。消毒剤耐性を有するマウスノロウイルスに関しては、遊離塩素に対し有意な耐性を保持する集団の取得に成功した。得られた遊離塩素耐性マウスノロウイル集団、および遊離塩素を用いずに希釈と培養のみを繰り替えした対照マウスノロウイルス集団に対し全ゲノム解析を行ったところ、遊離塩素耐性マウスノロウイルス集団に特異的な遺伝子変異を同定することに成功した。そのうちの1つはVP2と呼ばれるマイナー外殻タンパク質をコードする遺伝子中に存在しており、この変異によりマウスノロウイルス粒子の安定性が向上しているものと推測された。下水・汚水由来のノロウイルス遺伝子取得に関しては、仙台市内の下水処理場で採取した未処理下水から得られたノロウイルス遺伝子配列の取得に成功した。
  • 次世代シーケンシングによる温暖化適応遺伝子のゲノム検索:遺伝的多様性予測への活用
    日本学術振興会:科学研究費助成事業 挑戦的研究(萌芽)
    研究期間 : 2019年06月 -2021年03月 
    代表者 : 渡辺 幸三
  • 洪水に伴うデング熱媒介蚊の生息分布と個体数の拡大過程の遺伝学的推定:温暖化の影響
    日本学術振興会:科学研究費助成事業 特別研究員奨励費
    研究期間 : 2019年04月 -2021年03月 
    代表者 : 渡辺 幸三, CARVAJAL Thaddeus Marzo
  • なぜノロウイルスがカキに蓄積するのか?そのメカニズムの解明
    日本学術振興会:科学研究費助成事業 挑戦的研究(開拓)
    研究期間 : 2017年06月 -2020年03月 
    代表者 : 大村 達夫, 藤井 学, 三浦 尚之, 渡辺 幸三, 佐野 大輔
     
    カキを養殖している内湾の河口から沖に向かった縦断方向に位置する5地点において海水200~560Lに含まれる植物および動物プランクトン試料を採取用ネット(目合0.1mmおよび目合0.072mm)をそれぞれ用いて採取した。また,5地点のうち1地点では,養殖カキも同じ日に採取した。調査は2018年11月6日、12月20日、2019年2月4日にそれぞれ行った。プランクトン採取時のばらつきを評価するため,各地点において濃縮試料(約40mL)のレプリケートを3~4本採取した。採取したプランクトン試料は顕微鏡下で,動物,植物プランクトンに形態学的にソーティングした。カキ試料からは中腸線を取り出し,湿重量を計量したのちに,定量PCRによるノロウイルスの検出および定量,そしてDNAメタバーコーディングによるカキの食性解析のために冷凍保存した。 形態学的ソーティングの結果,採取用ネットの目合(0.1mmおよび0.072mm)の違いに依らず,動植物プランクトンが混在した形で採取されていることが確認された。ただし,割合としては,0.072mm目合ネットの方が植物プランクトンの個体数の割合が全体的に高まっていた。リアルタイムPCRによるノロウイルスの検出の結果,一部サンプルからノロウイルスが検出された。サンプル中の動物および植物プランクトンの個体数を形態学的に定量した結果,動物プランクトンの個体数の割合が高い地点のサンプルほど,ノロウイルス濃度が低下している相関関係が観察された。また,カキ中腸線のDNAメタバーコーディング解析を行い,カキが動物および植物プランクトンの双方を捕食していることも確認された。
  • 東南アジアにおける環境と健康のデータベース構築
    日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2017年04月 -2020年03月 
    代表者 : 福士 謙介, 渡部 徹, 渡辺 幸三
     
    【暑熱環境班】暑熱環境の解析をベトナム(ハイフォン、フエ、ダナン)、インドネシア(メダン市、スラバヤ市、デンパサール市、北スマトラ州、東ジャワ州、バリ州)において、現在、将来に関して実施し、計算結果、計算するために必要なデータの収集と整理を行った。一方、国立環境研究所・気候変動適応センターとアジア太平洋気候変動適応情報プラットホーム(AP-PLAT)における本事業で収集整理したデータの効率的な格納方法、表示方法に関して検討し、2020年までには同プラットホーム上で本事業の成果を公表可能にする方向で検討することとなった。 【水系感染症班】ベトナム・フエを対象に、カウンターパートの協力を得ながら、洪水時の溢水のサンプリングを実施した。また,洪水時と平常時の感染症発生状況を把握するため、都市下水のサンプリングも実施した。そこで採取したサンプルからは、感染症リスク評価に必要な糞便汚染指標細菌(大腸菌、腸球菌)やノロウイルスの検出をそれぞれ行った。さらに、農作物の汚染を介した間接的な感染症リスクを検討するために、都市下水に起因する都市近郊農地の汚染に関する情報収集も行った。 【ベクター感染症班】前年度から継続して、インドネシア全土およびフィリピン全土から各国のカウンターパートと協力して、デング患者の疫学データを国際機関と国の保健機関から収集した。また、デング熱小児患者の心理的負担(うつ病率等)についてのデータも収集し、約2割のデング熱小児患者がうつ病を発症していることを明らかにした。さらに、トラップを使った蚊生息数データの収集を、マニラおよびバンドンで継続的に行った。蚊に刺された場所と時間データをスマートフォンを介して広範囲から収集するアプリを開発できた。インドネシアを網羅する約8割の県を対象として、各県の気象変数からデング熱感染リスクを予測する機会学習モデルを作成した。
  • 流況・土砂管理を組み合わせたダム下流の自然再生事業の生態学的評価
    日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2017年04月 -2020年03月 
    代表者 : 角 哲也, 竹門 康弘, 渡辺 幸三
     
    平成29年度にトリニティ川で調査した「河川管理(流況・土砂供給)」,「生息場構造」「生物多様性 」「水質浄化機能」の4要素間の関係を分析するとともに、天竜川と木津川を中心とした国内河川で同様の調査を行って比較分析を行った。平成30年度は、平成29年度に実施した、課題1の河川管理の違いが生息場構造や河床状態に及ぼす影響の解明、および、課題2の河川管理の結果形成された生息場構造が生物多様性(魚類・底生動物)に及ぼす影響に加えて、課題3の砂州フィルタリングによる水質浄化機能に及ぼす影響について取り組んだ。 課題1に関しては,ルイストンダム下流区間ならびに天竜川船明ダム下流区間の調査結果をもとに,面積比,頻度比,生息場多様度等の生息場構造指標を評価し,「流量変動や土砂供給量が中程度の状況下で生息場構造の多様性や河床間隙が最も高まる」という仮説を検証した。 課題2では,生息場ごとに底生動物と魚類の種多様性,種構成,個体数,エネルギー寄与率等の生態学的指標を評価するために ,課題1で明らかにされた生息場構造指標,砂州形状特性値や河床材料に関するデータとの定量関係を回帰分析で導き,流況や 土砂管理による生息場の改善が生態学的指標の変化に繋がっているのかを定量的に検証した。 課題3では,生息場構造の水質浄化機能を評価するために, 平成29年度に行った調査結果をもとに,濁度,懸濁成分量(SS, 強熱減量),粒状有機物の安定同位体比,溶存酸素や栄養塩等の水質項目について,砂州内流下方向の変化を評価するとともに ,河床内に生息する微生物群集の種組成について,次世代シーケンサーを用いたメタゲノム解析で種を同定した。そして,砂州リフレッシュによる微生物群集組成の更新と共に,生物学的な水質浄化機能の改善に繋がっている分類群等を特定し,砂州形状や河床間隙率の違いが水質浄化機能に及ぼす影響を明らかにした。
  • 日本学術振興会:科学研究費助成事業 挑戦的研究(萌芽)
    研究期間 : 2017年06月 -2019年03月 
    代表者 : 渡辺 幸三
     
    デング熱はネッタイシマカ等の蚊が媒介するウイルス感染症での感染環により流行が拡大する。本研究は,次世代シークエンシング(RNAseq)を用いたゲノムワイドの比較遺伝子発現解析により,ネッタイシマカへのデングウイルス感染抑制に寄与している遺伝子群とその生物学的機能を推定した。比較遺伝子発現解析には,デングウイルスに感染している個体,ボルバキアに感染している個体,両者に感染していない個体を用いた。解析の結果,ウイルス感染に関与している69個の遺伝子が探索された。これらはセリンプロテアーゼ活性,ATP結合,匂い分子結合タンパク質などの機能に関与していることが推定された。
  • 河川底生動物のゲノムワイド遺伝子発現解析による地球温暖化への適応と脆弱性の評価
    日本学術振興会:科学研究費助成事業 特別研究員奨励費
    研究期間 : 2017年04月 -2019年03月 
    代表者 : 渡辺 幸三, GAMBOA MENDEZ MARIBET ARIANA
     
    【研究背景】膨大なゲノムには水質・水温・流速等の様々な環境因子の自然選択を受けた遺伝子が数多く存在する。この環境選択性遺伝子を同定できれば,生物の適応的進化の理解が促進される。この遺伝子と環境を直接関連付ける適応的進化の理解により,将来の気候変動や土地利用変化などの環境変化後の遺伝的多様性の劣化をより正確に予測することが可能となる。 【研究目的】水温の変化に敏感な河川水生昆虫カワゲラを対象に,日本列島の寒冷~亜熱帯の気候勾配に沿った適応的なRNAレベルの遺伝構造の変化を調べて,将来の気候変動(地球温暖化)に伴う遺伝的多様性の劣化や種の絶滅の可能性を予測する. 【方法】札幌,仙台,岐阜,松山の日本列島の気候条件に沿った4地域の流域において,河川水生昆虫カワゲラの幼虫個体を採取した。生物個体の採取と共に,遺伝的な適応に関係する可能性のある気温・水温・流速・河床材料などの物理的環境の現地調査,GISを使った土地利用状況(農地,山林等)や都市化率の定量化など,環境条件を多岐に渡って調査した。さらに,次世代シークエンサー(HiSeq 4000)を使ったゲノムワイドのトランスクリプトーム解析により,DNAから翻訳されたmRNAライブラリーの配列データを取得した。 【結果および考察】次世代シーケンス解析から353,352配列が得られた.その内,BLAST検索でヒットしたのは1732配列,411個の遺伝子がアノテーションされた.地域間において共通の遺伝子領域は1つのみだったが,特異な遺伝子領域は390個とはるかに多かった.特に札幌では他3地域より約40個多い131個の遺伝子領域が特異だった.アノテーションされた遺伝子領域が札幌において143個で他3地域より40個以上多かったことから,極端な環境状態に適応するためにカワゲラはより多くの遺伝子を発現する必要があると推測された.
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2016年04月 -2019年03月 
    代表者 : 渡辺 幸三, 加藤 幹男, 八重樫 咲子, 竹門 康弘
     
    従来の一種限定の評価から脱却し,全生息種を対象に,生息地分断化や環境選択の遺伝子レベルの生態影響を迅速かつ安価に評価する新規的技術を開発した。次世代DNAシーケンス解析技術とDNAバーコーディングを活用し,瀬切れ河川重信川における水生昆虫15種の流域内交流解析を同時に行った.その結果,多くの種は瀬切れによる流域内交流への影響がみられなかった一方で,Baetis sp. とChironomus kiiensisは瀬切れによる移動分散阻害が発生していた.今後,NGS解析による多数種の移動分散パターン解析技術が実現することで,生態系に配慮した河川管理へ応用されることが期待される.
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2016年04月 -2019年03月 
    代表者 : 渡辺 幸三, 糠澤 桂, 大村 達夫, 八重樫 咲子
     
    デング熱が流行するフィリピンで採取したネッタイシマカからデングウイルスと蚊共生細菌ボルバキアを検出した。その結果,ターラック市におけるネッタイシマカのデングウイルス陽性率は、メス成虫359個体のうち10個体(2.8%)が陽性であった。また,多くの村でデング熱患者とネッタイシマカから異なる血清型が検出され,デングウイルスの空間伝播が大きな空間スケールで起きていることが示唆された。また,メトロマニラで採取した672個体のネッタイシマカのうち80個体(12%)がボルバキアを有していることが明らかにされた。また,気象水文変数によりメトロマニラのデング罹患率の経週変化を予測する機械学習モデルを開発した。
  • 日本学術振興会:科学研究費助成事業 基盤研究(C)
    研究期間 : 2016年04月 -2019年03月 
    代表者 : サトウ 恵, 渡辺 幸三, 中尾 稔
     
    2016年から2018年度の3年間で新潟県下においてマダニの採取を行った。マダニ種の分類を行い、それぞれの地域において現在分布しているマダニ種のおおよその把握を行うことができた。新潟県で現在確認されたマダニ種は14種で、1950年代には見られなかった南方系のマダニ種も確認している。またマダニが保有しているリケッチア、ボレリアの検出を行い、それぞれに病原 体の種特異性を確認した。検出されたリケッチアはR. asiatica, R. helvetica, R. monacensis の3種であった。ボレリアはB. japonica,B. miyamotoiまた、種不明Borrelia属が検出された。
  • 日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2015年04月 -2018年03月 
    代表者 : 大村 達夫, 李 玉友, 佐野 大輔, 渡辺 幸三
     
    本研究では、ヒトノロウイルスの代替としてマウスノロウイルス、ヒトロタウイルスとしてサルロタウイルスを用い、遊離塩素への繰返し曝露がもたらすウイルス集団の適応進化に関する研究を行った。その結果、両方のウイルスに関し、遊離塩素への繰返し曝露により遊離塩素耐性集団を得ることに成功した。マウスノロウイルスに関しては外殻タンパク質遺伝子配列、サルロタウイルスに関しては全ゲノム配列の解析を行ったところ、遊離塩素への繰返し曝露により、ある特定の形質を有する株の優占が生じることが明らかとなった。以上の結果から、水処理によく用いられる遊離塩素処理が、胃腸炎ウイルスへの淘汰圧として働いていることが示された。
  • 日本産河川昆虫カワゲラの種多様性の系統発生学的再評価:DNAと形態に基づく種分類
    日本学術振興会:科学研究費助成事業 特別研究員奨励費
    研究期間 : 2015年04月 -2017年03月 
    代表者 : 渡辺 幸三, MURANYI DAVID
     
    本研究は、ヨーロッパ,北アメリカ,日本広域を網羅する東アジアから採取した成虫標本を用いて、カワゲラ目クロカワゲラ科の属ならびに種の定義を見直した。形態学的分析とDNA塩基配列に基づいて、(1)クロカワゲラ類の時間的,地理的な進化過程を明らかにすること,(2) クロカワゲラ類の属間の形態形質の進化パターンを明らかにすること, (3) DNAデータベースの充実化に向けクロカワゲラ類のCOI塩基配列とHistone H3塩基配列を解読し決定することを目的とした解析を行った.主な結論を以下にまとめる. (1) クロカワゲラ科224サンプルから形態同定により未記載属7属,未記載種15種が確認された.形態だけでなく分子系統樹においてもこれらの属の単系統が示されたことにより,形態同定の正確性が裏付けられた.なお,未記載属Aのアメリカ産と日本産は系統の異なる別属であることが示唆された.日本産クロカワゲラ科のいずれの種も,現在のCapnia属の狭義の形態学的定義には当てはまらないことが明らかになった。これらは我々が定義しようとしている新たな属に分類されるものと考えられる。 (2) ベイズ推定法による分子系統樹からクロカワゲラ類の時間的,地理的な進化過程が推定された.日本産の属の多くが単系統群に当てはまり,日本産クロカワゲラは大きく分けて3つの系統から成ることが示された.. (3) 遺伝距離と形態形質の距離の間に正の相関があることが示された.クロカワゲラ科は遺伝的な差が大きくなるほど形態も異なっている. (4) クロカワゲラ科19属62種のCOI配列を220配列,Apteroperla(ハダカカワゲラ)属6種のHistone H3配列を28配列解読した.これらの配列データをDNAデータベースに登録し,DNAバーコーディングの精度向上に役立てられるものと考えられる.
  • 日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2014年04月 -2017年03月 
    代表者 : 福士 謙介, 渡部 徹, 渡辺 幸三
     
    アジアの途上国都市を想定し、気候変動や社会変動の影響を考慮した洪水起因の感染症リスクの定量評価モデルを構築した。まず,洪水時の行動を考えたQMRAを基本とし、家庭内における二次感染を考慮したモデルにより、ノロウイルス感染リスクを算出した。次に,気候パラメータにもとづくデング熱のリスク評価モデルを、デング熱罹患率の季節変動と都市内での空間変動に着目しながら,機械学習アルゴリズムを用いて構築した。 最後に,現地でのインタビュー調査により,洪水時に頻発する感染症の種類とそれに対する住民の感情を明らかにした。その結果にもとづいてDALYの算出手法を改良し、洪水時の感染症による経済損失を評価した。
  • 日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2014年04月 -2017年03月 
    代表者 : 角 哲也, 堤 大三, 竹門 康弘, カントウシュ サメ・アハメド, 渡辺 幸三, 山上 路生
     
    1.日本とスイスのバイパストンネルの形状・設計流速・通過礫の粒度・岩質・年運用日数、通過土砂量などのデータを収集整理した。 2.(1)関西電力旭ダムの摩耗実績に関するデータを収集し、実績の流砂量を用いて、日本で広く用いられている摩耗予測式(石橋式)とスイス連邦工科大学で提案された摩耗予測式の両者の比較検討を行った。(2)流砂量の観測技術において、従来のパイプ型ハイドロフォンに対して、高流速・大粒径の衝撃に耐えうるプレート型ハイドロフォンを開発した。水理実験により、計測可能な流砂の粒径範囲や、流砂量の推定に最適な信号(ゲイン)を特定し、通過礫の検知率が、流砂の飽和度と衝突率で表されることを示した。
  • 日本学術振興会:科学研究費助成事業 基盤研究(C)
    研究期間 : 2014年04月 -2017年03月 
    代表者 : 三宅 洋, 井上 幹生, 渡辺 幸三, 吉村 研人, 岡田 裕成, 泉 哲平, 渡辺 裕也, 椋田 勇希, 森 照貴, 川西 亮太, 赤坂 卓美
     
    本研究は,既存の国内流量・生物データを活用した大規模解析を行うことにより,流量変動-河川生物群集関係を広域的に解明することを目的とした。この結果,国内河川において底生動物・魚類の保全に考慮した流量管理を行う際には,出水の継続時間および春季出水規模に注目するべきであることが示された。これら流量レジーム特性の改変に関与しているダムの運用方法の改善および土地利用の影響の緩和が河川生態系の保全にあたっては重要であることが示唆された。
  • 日本学術振興会:科学研究費助成事業 挑戦的萌芽研究
    研究期間 : 2014年04月 -2017年03月 
    代表者 : 渡辺 幸三, 風間 聡
     
    気候変動モデルのダウンスケーリングを行い,複数のシナリオ下における降水量・気温を予測した.そして,分布型流出モデルを活用して流域内の流速・水深・水温の空間分布を予測し,MaxEntにより,各シナリオ下の水生昆虫4種の対象流域内の生息分布を推定した。さらに,ゲノムワイドの遺伝子データからBayeScanおよび自己組織化特徴マップ解析により環境選択性遺伝子座を同定した。そして,水温・流量等の変数と対立遺伝子頻度の関係を表す重回帰モデルを作成し,気候変動下の環境選択性遺伝子座と遺伝的多様性の空間分布を予測した。その結果、水温による自然選択を強く受けていた種の遺伝的多様性の著しい劣化が予想された。
  • 日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2013年04月 -2017年03月 
    代表者 : 竹門 康弘, 吉村 千洋, 渡慶次 睦範, 角 哲也, 堤 大三, 風間 聡, 藤田 正治, 竹林 洋史, 渡辺 幸三
     
    河川生態系では生息場が動的な存在であることを前提に管理する必要がある。本研究では生息場寿命の視点から、天竜川、木津川、タリアメント川などの地形と生態現象の関係を調査し、生息場を好適化する撹乱条件を明らかにした。その結果、アユの産卵場には軟底の瀬が必要であり、4.5年確率の大規模出水時に好適化し、1年確率以下の中小規模出水時に劣化することがわかった。一方、タナゴ類やイシガイ類の生息するたまりは、2年前の泥の堆積厚が5-10cmで冠水頻度が年3回以下(現状の冠水日数8~22日の比高)であり、このような砂州地形を維持するには、4万~6万m3/年程度の土砂移動量が適していると推定された。
  • 河川水生昆虫カワゲラの環境適応と遺伝的分化:ゲノムとタンパク質の進化
    日本学術振興会:科学研究費助成事業 特別研究員奨励費
    研究期間 : 2013年04月 -2016年03月 
    代表者 : 渡辺 幸三, GAMBOA MARIBET, GAMBOA Maribet
     
    気候勾配に沿った札幌・仙台・岐阜・松山の4地域の河川から,45種・1457個体の水生昆虫カワゲラの幼生個体を採取した。また,現地で補足的に行った成虫のサンプリングにより,12種から成る89個体の成虫個体も採取した。 RADシークエンシングにより,42種の計384カワゲラ個体から,合計約160億塩基のゲノムワイドのDNA塩基配列データを収集することに成功した。解読されたゲノム上の約300万塩基において,気候勾配に沿って設定した調査地域間における一塩基多型(SNP)が検出され,気候勾配に沿った遺伝的変異がゲノム上の広域で起きていることが解明された。 タンパク質レベルのプロテオーム解析では,2次元電気泳動によるタンパク分画解析から,気温の季節間変動が大きな札幌と岐阜では,他地域よりも多様なタンパク質を発現していることが分かった.解析をした7種のカワゲラのうち,Nemoura sp. ,Rhabiopteryx japonica ,Eucanopsis sp. ,Perlodini incertaeの4種は4地域で最も温暖な松山で特異的に発現したタンパク質数が他の地域より多いことから,温暖な地域に適応的な種である可能性が示された.一方,Amphinemoura sp. とHaploperla japonica の2種は札幌で特異的に発現したタンパク質数が多いことから,寒冷な地域に適応的な種と推察された.さらに,各地域に固有に発現していた計111種類(スポット)のタンパク質を選択して,更に高度なアミノ酸配列情報等を取得するMALDI-TOF/TOFを行い,タンパク質を同定した. ゲノムワイドのmRNAの発現をトランスクリプトーム解析で調べた。7種の計46個体のカワゲラから,合計約6300万塩基のゲノムワイドのmRNA塩基配列データを収集し,411個の遺伝子のうち11個はもっとも寒冷な札幌で特異的に検出されていることがわかった.
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2013年04月 -2016年03月 
    代表者 : 渡辺 幸三, 大村 達夫, 加藤 幹男, 三宅 洋
     
    愛媛県重信川の10地点に生息する河川底生動物群集を対象に,大量のDNA塩基配列を一度に解読する次世代シークエンシング解析を活用し,迅速に種数を評価した.従来の顕微鏡を使った形態同定の結果,採取された8,921個体から64分類群が発見された.それに対して,ミトコンドリアDNAのCOI領域(658塩基長)を対象とした次世代シークエンシング解析で得られた165,508配列の内,DNAバーコーディングにより39,337配列から成る128種が同定された.また,各分類群における個体数とDNA配列数に正の相関が見られた.またDNA種分類法(PTPモデル)を適用した結果,298種の存在が推定された.
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2013年04月 -2016年03月 
    代表者 : 渡辺 幸三, 大村 達夫, 渡部 徹, 押谷 仁, 齊藤 麻理子
     
    フィリピンのメトロマニラとターラックにおいて,デングウイルスを媒介するネッタイシマカ成虫を採捕して,DNA多型解析を行った。その結果,蚊の交流範囲や蚊の飛翔範囲が5km未満など,デングウイルスの伝播範囲の予測に繋がるベクターの空間生態を明らかになった。また,メトロマニラの全604行政区における洪水強度と土地利用区分に関するGISデータを整備し,これらを説明変数として,行政区間のデング感染率(人口当たり感染数)の違いを記述する回帰木モデルを作成した。高い精度で実測されたデング感染率を説明するモデルが構築され,洪水がリスク因子としての寄与率が高いことも示された。
  • 日本学術振興会:科学研究費助成事業 挑戦的萌芽研究
    研究期間 : 2013年04月 -2015年03月 
    代表者 : 佐野 大輔, 渡辺 幸三
     
    本研究では、ノロウイルスの塩素消毒耐性獲得メカニズムを解明することを目的とした。その結果、繰り返し遊離塩素に曝露することで、マウスノロウイルスの集団が塩素耐性を獲得することが可能であり、それはある特定の株が優占することによって生じる現象であることが確認された。なお、本研究の成果は計3つの学会で発表されたが、そのうち第55回臨床ウイルス学会において本研究の先駆性が認められ、研究代表者は若手奨励賞を受賞した。
  • 日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2012年04月 -2015年03月 
    代表者 : 大村 達夫, 吉村 千洋, 竹門 康弘, 風間 聡, 西村 修, 渡辺 幸三
     
    本研究は,ヨーロッパアルプスの中で例外的に残された北東イタリアの自然流域を参照し,自然再生で目指すべき種多様性の目標像を示すことを目的とする.DNA種分類に基づいて,未記載種も含む河川底生動物群集の種多様性を評価し,生息場間の環境多様性や流倒木などの微笑生息場の生態学的な重要性が確認された.また,自然氾濫原における洪水撹乱による生息場地形の更新(生息場寿命)が種多様性を維持する機構も解明した。
  • 日本学術振興会:科学研究費助成事業 研究活動スタート支援
    研究期間 : 2012年08月 -2014年03月 
    代表者 : 渡辺 幸三
     
    愛媛県重信川流域の15地点において,2012年5月,8月,11月,2月に環境調査と河川底生動物群集の採取を行った。これらの調査地点は「流域」,「セグメント(流程)」,そして「リーチ(蛇行区間)」の3つの異なる空間階層スケールで種多様性を評価するデザインで選択した。環境調査は,水質,餌資源,流速,水深,河床材料など幅広く行った。2012年8月に採取した底生動物群集サンプルを,従来の顕微鏡観察に基づく形態学的種分類に基づく種多様性評価を完了したのちに,次世代DNAシークエンシング解析に用いた。このDNA分析では,まず各地点の生物群集試料から一度にDNAを抽出し,雑多な種が混在するDNAを対象にして,マルチプレックスPCRでミトコンドリアDNAのCOI領域(672bp)を増幅した。その後,雑多な種のPCR産物(アンプリコン)を,Roche 454 Sequencerを用いたパイロシークエンシング法に基づき,次世代DNAシークエンシング解析した。その結果,平均400bp長の塩基配列データを約17万配列を一度に作成することに成功した。この大規模DNAデータベースは引き続き実施される各調査地点の種多様性(種数)の評価に用いられる。具体的には,進化モデルと絶滅モデルを融合したGeneralized Mixed Yule-Coalescent(GMYC)モデルに適用することで,塩基配列間の非類似性に基づいて種の境界を定義して種数を定量化する。
  • 水生昆虫集団の個体群動態の履歴に因る遺伝構造の形成と生息地分断による遺伝的分化
    日本学術振興会:科学研究費助成事業 特別研究員奨励費
    研究期間 : 2006年 -2008年 
    代表者 : 渡辺 幸三
     
    宮城県中南部地域4水系の源流から下流の30地点に分布するヒゲナガカワトビケラ局所個体群の遺伝構造をAFLPマーカーおよびミトコンドリアDNA(COI領域)マーカーで解析し,局所個体群間の移動分散パターンを評価した。地点間の遺伝距離に基づく系統樹の結果から,源流の局所個体群が中流以降の大部分の個体群から遺伝的に隔離されていることが明らかになった。ヒゲナガカワトビケラは,雌成虫が河道に沿って産卵遡上する行動が観察されているが,本研究の結果は,風分散により方向性を持たない成虫の移動が起きている可能性を示した。また,ミトコンドリアDNAの塩基置換数から,源流の多くの個体に見られた遺伝子群は,中流以降に多く見られる遺伝子群から約70万年前に独自に進化した特殊な遺伝子群と推定された。源流域はヒゲナガカワトビケラに高い遺伝的多様性を残すために極めて重要な地域であるが,上述したように強く隔離されているため,個体群の存続が困難になっていることが明らかにされた。 成虫の分散能力が異なるウルマーシマトビケラ(分散力低い),ヒゲナガカワトビケラ(中),オオクママダラカゲロウ(高)の3種を対象に,規模が大きく異なる7つのダム(湖長=0.1〜5km)上下流間の分集団間の遺伝子類似性を調べた。その結果,分散能力が中程度で,一世代当たりの異動距離がダム湖の長さとほぼ一致するヒゲナガカワトビケラのみ,ダムにより地域交流が遮断されている可能性が示された。さらに,ヒゲナガカワトビケラの集団遺伝構造を感度良くかつ安価に調べることを可能にするマイクロサテライト領域を増幅するPCRプライマーを10ペア開発した。本研究により,局所個体群間の繋がりや移動分散パターンに関する理解を深めるツールとして,DNA多型解析は高いポテンシャルを有することが示された。
  • 年周期性を考慮したダム放流水が河川底生動物相に与える影響メカニズムの解明
    日本学術振興会:科学研究費助成事業 特別研究員奨励費
    研究期間 : 2002年 -2004年 
    代表者 : 渡辺 幸三
     
    本研究は河川底生動物に対するダム放流水の影響メカニズムを解明し,河川底生動物相への影響を最小化するダムの運転・管理手法の提案を目的としている. 本年度は昨年度に引き続き、主にダム湖の上下流側に生息する底生動物個体群のDNA多型をRAPD調査し,ダム湖による生息地の分断化がダム湖上下流間の遺伝子流動(遺伝子の個体群間の移動)の低下に及ぼす影響評価を行った.調査は田瀬ダム,遠野ダム(岩手県),大倉ダム(宮城県),下久保ダム(群馬県),刀利ダム,室牧ダム(富山県)の計6つのダムを対象に行った.これらのダム湖は湛水面積が大きく異なるため,生息地分断の規模が遺伝子流動の阻害度に影響するかの検証に適している.遺伝子流動の阻害の有無は,ダム上下流地点間のNeiの遺伝距離を、ダムで分断された河川に隣接するコントロール河川(ダムで分断されていない河川)の遺伝距離と比較することで評価した.対象種はヒゲナガカワトビケラである. 解析の結果、6つのダム湖のうち,湛水面積が3.27km^2以上の2つのダム湖において統計的に有意な遺伝的分化が起きていることがわかった.また,遺伝的多様性を低下させる要因として,ダムによる遺伝子流動の低下よりも,各地点の集団サイズの低下がより強く影響していることが明らかになった.これらの研究成果は土木学会第59回年次学術講演会(2004年9月愛知県)で発表し、さらに土木学会論文集への掲載が決定された.

委員歴

  • 2019年06月 - 現在   土木学会   四国支部幹事
  • 2018年04月 - 現在   応用生態工学会   国際交流委員会 委員長
  • 2017年05月 - 現在   日本水環境学会   運営幹事
  • 2017年05月 - 現在   日本水環境学会   WET部会 部会長
  • 2015年05月 - 2019年03月   土木学会   環境工学委員会 委員兼幹事
  • 2016年06月 - 2018年06月   土木学会   土木学会論文集G分冊小委員会 委員
  • 2016年04月 - 2018年03月   応用生態工学会   国際交流委員会 委員
  • 2016年08月 - 2017年04月   日本水環境学会   WET 部会 運営委員
  • 2015年08月 - 2017年04月   土木学会   環境賞選考委員会 委員
  • 2013年04月 - 2016年03月   国土交通省   鳴子ダム水質保全対策委員会 委員
  • 2013年06月 - 2015年06月   土木学会   土木学会誌編集委員会 委員
  • 2006年04月 - 2008年03月   財団法人リバーフロント整備センター   DNA多型分析技術応用研究会 委員

愛媛大学教員活動実績

教育活動(B)

担当授業科目(B01)

  • 2019, 前期, 学部, 技術英語I
  • 2019, 前期, 学部, 建設倫理
  • 2019, 前期, 修士, 生物多様性と人間活動
  • 2019, 前期, 修士, 技術英語プレゼンテーション


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