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Nishitani G, Yamamoto K, Nakajima M, Shibata Y, Sato-Okoshi W, Yamaguchi M. A novel parasite strain of Amoebophrya sp. infecting the toxic dinoflagellate Alexandrium catenella (Group I) and its effect on the host bloom in Osaka Bay, Japan. HARMFUL ALGAE 2021; 110:102123. [PMID: 34887003 DOI: 10.1016/j.hal.2021.102123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 10/05/2021] [Accepted: 10/09/2021] [Indexed: 06/13/2023]
Abstract
The endoparasitic dinoflagellates belonging to the genus Amoebophrya can infect a broad range of free-living marine dinoflagellates, including harmful/toxic species. The parasite kills its host; the high prevalence of the parasite has been suggested to be a significant factor for the termination of dinoflagellate blooms in marine systems. The issues involved in culturing host-parasite systems have greatly restricted further research on Amoebophrya biology. Here, we established the culture of a novel strain of Amoebophrya sp. ex Alexandrium catenella (Group I) from Osaka Bay, Japan, and studied its genetic diversity, host specificity, and prevalence in the field. Genetic analysis established that the strain we isolated was a novel culture strain infecting A. catenella. Among the host species tested, the Amoebophrya sp. could infect the genera Alexandrium and Prorocentrum in culture, and the infection was also confirmed in the genus Tripos in a field sample. A maximum prevalence of 73% was recorded during the Alexandrium bloom period in Osaka Bay, after which the host cell density rapidly declined. Our results indicated that the existence of the parasite had a significant effect on the dynamics of A. catenella, especially on the termination of the blooms.
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Affiliation(s)
- Goh Nishitani
- Graduate School of Agricultural Science, Tohoku University, Aoba 468-1, Aramaki, Aoba-ku, Sendai, 980-0845, Japan.
| | - Keigo Yamamoto
- Marine Fisheries Research Center, Research Institute of Environment, Agriculture and Fisheries, Osaka Prefecture, Misaki, Sennan, Osaka, 599-0311, Japan; Research Institute of Environment, Agriculture and Fisheries, Osaka Prefecture, 442 Shakudo, Habikino, Osaka, 583-0862, Japan
| | - Masaki Nakajima
- Marine Fisheries Research Center, Research Institute of Environment, Agriculture and Fisheries, Osaka Prefecture, Misaki, Sennan, Osaka, 599-0311, Japan
| | - Yoshiki Shibata
- Graduate School of Agricultural Science, Tohoku University, Aoba 468-1, Aramaki, Aoba-ku, Sendai, 980-0845, Japan
| | - Waka Sato-Okoshi
- Graduate School of Agricultural Science, Tohoku University, Aoba 468-1, Aramaki, Aoba-ku, Sendai, 980-0845, Japan
| | - Mineo Yamaguchi
- School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
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Duan Y, Sen B, Xie N, Paterson JS, Chen Z, Wang G. Flow Cytometry for Rapid Enumeration and Biomass Quantification of Thraustochytrids in Coastal Seawaters. Microbes Environ 2018; 33:195-204. [PMID: 29910220 PMCID: PMC6031391 DOI: 10.1264/jsme2.me17162] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 03/21/2018] [Indexed: 11/23/2022] Open
Abstract
Marine fungus-like eukaryotic unicellular protists (thraustochytrids) are considered to play an important role in the marine microbial food web. However, their abundance, distribution, and relative biomass in coastal waters have not yet been examined in detail. By using a flow cytometry method (FCM) for the rapid enumeration of thraustochytrids in nearshore and offshore stations along the Gulf of Bohai, China, we herein expanded current knowledge on their ecological significance. The FCM method allows for the rapid detection and quantification of prokaryotic and eukaryotic cells, but is rarely applied to the enumeration of small eukaryotic protists. Epifluorescence microscopy (EpiM) has been commonly used for the direct detection and enumeration of thraustochytrids; however, this method is time-consuming and inapplicable to a large-scale analysis of complex seawater samples. There is no available FCM method to track the abundance and biomass of thraustochytrids in marine habitats. The FCM enumeration of thraustochytrids in seawater samples ranged between 400 and 4,080 cells mL-1 with a biomass range of 8.15-83.96 μg C L-1. The thraustochytrid biomass contributed 10.9% to 98.1% of the total biomass of the heterotrophic microbial community comprising bacterioplankton and thraustochytrids. Their overall abundance in nearshore stations was significantly different from that in offshore stations (P<0.5). The present results provide an optimized method for the rapid detection and enumeration of thraustochytrids in seawater and facilitate large-scale studies of the ecological role of thraustochytrids in the microbial food web of coastal waters.
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Affiliation(s)
- Yingbo Duan
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin UniversityTianjin 300072China
| | - Biswarup Sen
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin UniversityTianjin 300072China
| | - Ningdong Xie
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin UniversityTianjin 300072China
| | - James S. Paterson
- School of Biological Sciences, Flinders UniversityGPO Box 2100, Adelaide SA 5001Australia
| | - Zixi Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin UniversityTianjin 300072P. R. China
| | - Guangyi Wang
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin UniversityTianjin 300072China
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Affiliation(s)
- Shin Haruta
- Graduate School of Science and Engineering, Tokyo Metropolitan University
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Coelho SM, Simon N, Ahmed S, Cock JM, Partensky F. Ecological and evolutionary genomics of marine photosynthetic organisms. Mol Ecol 2012; 22:867-907. [PMID: 22989289 DOI: 10.1111/mec.12000] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 07/10/2012] [Accepted: 07/15/2012] [Indexed: 01/05/2023]
Abstract
Environmental (ecological) genomics aims to understand the genetic basis of relationships between organisms and their abiotic and biotic environments. It is a rapidly progressing field of research largely due to recent advances in the speed and volume of genomic data being produced by next generation sequencing (NGS) technologies. Building on information generated by NGS-based approaches, functional genomic methodologies are being applied to identify and characterize genes and gene systems of both environmental and evolutionary relevance. Marine photosynthetic organisms (MPOs) were poorly represented amongst the early genomic models, but this situation is changing rapidly. Here we provide an overview of the recent advances in the application of ecological genomic approaches to both prokaryotic and eukaryotic MPOs. We describe how these approaches are being used to explore the biology and ecology of marine cyanobacteria and algae, particularly with regard to their functions in a broad range of marine ecosystems. Specifically, we review the ecological and evolutionary insights gained from whole genome and transcriptome sequencing projects applied to MPOs and illustrate how their genomes are yielding information on the specific features of these organisms.
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Affiliation(s)
- Susana M Coelho
- UPMC-Université Paris 06, Station Biologique de Roscoff, Roscoff, France.
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Composition of the summer photosynthetic pico and nanoplankton communities in the Beaufort Sea assessed by T-RFLP and sequences of the 18S rRNA gene from flow cytometry sorted samples. ISME JOURNAL 2012; 6:1480-98. [PMID: 22278671 DOI: 10.1038/ismej.2011.213] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The composition of photosynthetic pico and nanoeukaryotes was investigated in the North East Pacific and the Arctic Ocean with special emphasis on the Beaufort Sea during the MALINA cruise in summer 2009. Photosynthetic populations were sorted using flow cytometry based on their size and pigment fluorescence. Diversity of the sorted photosynthetic eukaryotes was determined using terminal-restriction fragment length polymorphism analysis and cloning/sequencing of the 18S ribosomal RNA gene. Picoplankton was dominated by Mamiellophyceae, a class of small green algae previously included in the prasinophytes: in the North East Pacific, the contribution of an Arctic Micromonas ecotype increased steadily northward becoming the only taxon occurring at most stations throughout the Beaufort Sea. In contrast, nanoplankton was more diverse: North Pacific stations were dominated by Pseudo-nitzschia sp. whereas those in the Beaufort Sea were dominated by two distinct Chaetoceros species as well as by Chrysophyceae, Pelagophyceae and Chrysochromulina spp.. This study confirms the importance of Arctic Micromonas within picoplankton throughout the Beaufort Sea and demonstrates that the photosynthetic picoeukaryote community in the Arctic is much less diverse than at lower latitudes. Moreover, in contrast to what occurs in warmer waters, most of the key pico- and nanoplankton species found in the Beaufort Sea could be successfully established in culture.
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