Lysogenic cyanophages; molecular mechanisms of lysogeny and their role in marine ecosystems

溶原性噬藻体；

• 批准号: 09490034
• 负责人: OHKI Kaori
• 金额: $ 8.06万
• 依托单位: Tokai University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09490034/
• 关键词: Cyanophtes; Cyanobacteria; Cyanophage; Lysogenic phage; Phormidium spp.; Trichodesmium; Caribbean Sea; Marine ecosystems; Phormidium; trichodesmium

Recent studies have revealed that cyanophages are found not only in polluted waters near the coastal areas but also in clean waters such as the open ocean. These cyanophages are thought to have an important role in the regulation of cyanophyta (cyanobacterial) populations. Most of the isolated cyanophages are of the virulent type, and cells are rapidly lysed shortly after infection. The contribution of lysogenic phages to the regulation of cyanobacterial populations is unknown. The basic knowledge such as distribution of lysogenic cyanophages among marine cyanobacteria and molecular mechanisms for lysogeny are required to estimate the possible role of lysogenic cynophages in marine ecosystems. In our previous work, we found that a cyanophage had established the stable lysogeny in marine cyanobacteria, Phormidium persicinum Provasoli strain. The lytic cycle of lysogenized phage was induced by the addition of mitomicyn C or a brief UV-illumination. (1) Using the culture of P. persicinum … More cultures, I found that considerably large part of the lysogenized cyanophage were detected to be in lytic cycle in the Phormidium percicinum cultures without any artificial induction. (2) Considarably large numbers of marine Phormidium strains isolated from different areas harbored lysogenic cyanophages. Morphological characters, DNA-DNA hybridization and Western analysis of phage proteins suggested that different family of cyanophages were established the stable lysogeny in marine cyanobacteria. These results indicated that lysogenic cyanophages are ecologically important, because not only they regulated the host algal populations but also they become the source for continuous supply of free phage particles to the ambient sea waters. (3) A possible role of lysogenic cyanophage(s) in regulation of marine, aerobic diazotrophic cyanobacteria, Trichodesmium was studied using both isolated strains (NIBB 1067) and field samples collected from Caribbean Sea off Carrie Bow Cay, Belize. Trichodesmium spp. Are the most important primary producer in oligotrophic, tropical and sub-tropical oceans. The rapid cell lysis of Trichodesmium caused by the addition of mitomycin C was observed in both cultured and natural samples. Cyanophage particles were isolated from Trichodesmium NIBB1067. These results suggested that the lysogenic cyanophage(s) must play an important role in the food web of oligotrophic oceans. Less

最近的研究表明，噬藻体不仅存在于沿海地区的污染水域，也存在于公海等清洁水域。这些噬藻体被认为在蓝藻（蓝藻）种群的调节中起重要作用。大多数分离的噬蓝体是毒性型的，细胞在感染后很快被裂解。溶原噬菌体对蓝藻种群调节的贡献尚不清楚。了解溶原性噬藻体在海洋蓝藻中的分布以及溶原性的分子机制是评估溶原性噬藻体在海洋生态系统中可能发挥作用的基础。在我们之前的工作中，我们发现一种噬藻体在海洋蓝藻中建立了稳定的溶原菌，即Phormidium persicinum Provasoli菌株。通过添加丝裂霉素C或短暂的紫外线照射诱导溶原噬菌体的裂解周期。(1)利用P. persicinum的培养，我发现在没有任何人工诱导的情况下，在Phormidium pericinum培养中检测到相当大一部分溶原化的噬藻体处于裂解循环中。(2)从不同地区分离到的大量海洋磷菌均含有溶原噬藻体。形态特征、DNA-DNA杂交和噬菌体蛋白的Western分析表明，在海洋蓝藻中存在不同的噬藻家族，具有稳定的溶菌性。这些结果表明，溶原性噬藻体具有重要的生态学意义，因为它们不仅调节宿主藻类种群，而且成为持续向周围海水供应游离噬菌体颗粒的来源。(3)利用分离菌株（NIBB 1067）和在伯利兹Carrie Bow Cay加勒比海采集的野外样本，研究了溶原性噬藻体在海洋需氧重氮营养蓝藻Trichodesmium调控中的可能作用。Trichodesmium spp.是低营养、热带和亚热带海洋中最重要的初级生产者。在培养样品和天然样品中均观察到丝裂霉素C的加入引起了毛霉菌的快速细胞裂解。从trichodesium NIBB1067中分离到噬藻颗粒。这些结果表明，溶原噬菌体在低营养海洋的食物网中扮演着重要的角色。少

项目成果

Mulholland,M.R.,Ohki,K.Capone,D.G.: "Nitorogen utilization and metabolizm relative to patterns of N_2 fixation in cultures of Trichodesmium NIBB1067"J.Phycol.. 35. 977-988 (1999)

Mulholland，M.R.，Ohki，K.Capone，D.G.：“与 Trichodesmium NIBB1067 培养物中 N_2 固定模式相关的氮素利用和代谢”J.Phycol.. 35. 977-988 (1999)

Mulholland,Shoemaker Ohki,Capone: "Utilization of combined forms of N in cultures and naatural populations of Trichodesmium"Bulletin de I' Institut Oceanographique,Monaco. 279-286 (1999)

Mulholland、Shoemaker Ohki、Capone：“在Trichodesmium 的文化和自然种群中利用氮的组合形式”Bulletin de I Institut Oceanographique，摩纳哥。

池谷透、大城香: "ラン色細菌〔ラン藻・シアノバクテリア)"月刊海洋. (印刷中).

池谷彻、大城香织：《蓝藻[Cyanobacteria]》月刊 Kaiyo（正在出版）。

Ohki, K., Honjho, S.: "Oceanic picophytoplankton having a high abundance of chlorophyll b in the major light harvesting chlorophyll protein complex"Photosynthetic Research. 53. 121-127 (1997)

Ohki, K.、Honjho, S.：“海洋超微型浮游植物在主要的光捕获叶绿素蛋白复合物中具有高丰度的叶绿素 b”光合作用研究。

Mulholland, M. Shoemaker, Ohki, K. Capone, D.G.: "Utilization of combined form of N in cultures and natural populations of Trichodesmium"Bulletin de I'Institute Oceanographique, Monaco. 279-286 (1999)

Mulholland, M. Shoemaker, Ohki, K. Capone, D.G.：“在Trichodesmium 的培养物和自然种群中结合形式的氮的利用”摩纳哥海洋研究所公报。