Tomaru Yuji, Hata Naotsugu, Masuda Takeshi, Tsuji Masaharu, Igata Kuniyoshi, Masuda Yuji, Yamatogi Toshifumi, Sakaguchi Masao, Nagasaki Keizo
National Research Institute of Fisheries and Environment of Inland Sea, 2-17-5 Maruishi, Hatsukaichi, Hiroshima 739-0452, Japan.
Environ Microbiol. 2007 Jun;9(6):1376-83. doi: 10.1111/j.1462-2920.2007.01252.x.
We studied the ecological relationships between the bloom-forming dinoflagellate Heterocapsa circularisquama and its infectious viruses in field surveys conducted in western Japan. The occurrence of H. circularisquama blooms in Imari Bay during 2002 and in Ago Bay during 2002 and 2004 was accompanied by specific increase in abundance of viruses lytic to H. circularisquama. Using northern dot-blot analysis, approximately 96% of the clonal virus isolates collected in the field surveys positively reacted with a molecular probe specific for HcRNAV (H. circularisquama RNA virus); hence, viral impacts on H. circularisquama population observed in these field surveys are considered largely due to HcRNAV and/or its closely related viruses. The dynamics of type UA viruses and type CY viruses having complementary host ranges to H. circularisquama clones were different in each survey and considered to reflect fluctuations in abundance of their suitable host cells in situ. The dynamics of H. circularisquama and its viruses in Ago Bay from 2002 to 2004 suggests the concentration of HcRNAV in the sediment prior to the host's blooming season is a significant factor in determining the size and length of the H. circularisquama blooms. These results support the hypothesis that HcRNAV infection is one of the significant factors affecting the population dynamics of H. circularisquama in both quantity (biomass) and quality (clonal composition).
我们在日本西部进行的实地调查中，研究了形成水华的环状异帽藻（Heterocapsa circularisquama）与其感染性病毒之间的生态关系。2002年在伊万里湾以及2002年和2004年在阿古湾出现的环状异帽藻水华，伴随着对环状异帽藻具有裂解性的病毒丰度的特定增加。使用Northern斑点杂交分析，在实地调查中收集的约96%的克隆病毒分离株与针对HcRNAV（环状异帽藻RNA病毒）的分子探针呈阳性反应；因此，在这些实地调查中观察到的病毒对环状异帽藻种群的影响在很大程度上被认为是由于HcRNAV和/或其密切相关的病毒。对环状异帽藻克隆具有互补宿主范围的UA型病毒和CY型病毒在每次调查中的动态不同，并被认为反映了其合适宿主细胞在原位的丰度波动。2002年至2004年阿古湾环状异帽藻及其病毒的动态表明，宿主水华季节之前沉积物中HcRNAV的浓度是决定环状异帽藻水华规模和持续时间的一个重要因素。这些结果支持了这样的假设，即HcRNAV感染是影响环状异帽藻种群数量（生物量）和质量（克隆组成）动态的重要因素之一。
