Protistan grazing and viral infection of marine picoplankton: a role for the host cell surface?

海洋超微型浮游生物的原生生物放牧和病毒感染：宿主细胞表面的作用？

• 批准号: NE/J020745/1
• 负责人: Mikhail Zubkov
• 金额: $ 9.29万
• 依托单位: NATIONAL OCEANOGRAPHY CENTRE
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FJ020745%2F1
• 关键词: Protistan; grazing; viral; infection; marine

The oceans play a major role in determining the world's climate. In part this is due to the production of oxygen and the consumption of carbon dioxide by very small, single celled organisms, which are referred to as the photosynthetic picoplankton. Marine cyanobacteria of the closely-related genera Prochlorococcus and Synechococcus are the prokaryotic components of the photosynthetic picoplankton. These cyanobacteria are continually growing and dividing, but they are also continuously being consumed. There are two major processes that contribute to the consumption of these cells. Firstly, they can be infected and killed by viruses and secondly they can be used as food by small single celled grazing animals called protists. It is the interaction between these two processes of mortality, together with the defence mechanisms that the cyanobacteria have developed, which are the focus of this research project. We recently observed that a marine Synechococcus strain that was infected with a virus was more susceptible to grazing than the uninfected culture. This distinct preference for preying on phage-infected cells has potentially important ecological implications, as it interferes with phage proliferation by removing infected cells before they burst and could thus indirectly reduce phage abundance. It is not yet clear what determines the palatability of a prey cell. Cell surface properties are likely to play a role and we have preliminary evidence that lipopolysaccharide (LPS) components of the cell wall are critical in this respect. This proposal will thus compare protist feeding on virus-infected, uninfected and LPS-modified Synechococcus strains in order to specifically elucidate the role of LPS in prey digestibility. Moreover, we will extend our studies to the Atlantic Ocean to investigate whether cultured protists graze differentially on natural Synechococcus populations, and in so doing establish the role of strain selectivity, or preference for cyanophage-infected cells, in this processOverall, the project will provide fundamentally new mechanistic information on the major biological loss processes that dictate the growth rate and yield of a key marine photoautotroph, information which is critical for defining and understanding controls on marine photosynthesis.

海洋在确定世界气候方面起着重要作用。在一部分中，这是由于非常小的单细胞生物的氧气产生和二氧化碳消耗，这被称为光合作用的皮科普兰克顿。密切相关属氯环球菌和共氯环球菌的海洋蓝细菌是光合作用皮科普兰克顿的原始成分。这些蓝细菌正在不断增长和分裂，但它们也不断消耗。有两个主要过程有助于消耗这些细胞。首先，它们可以被病毒感染和杀死，其次可以被称为生物的小单细胞放牧动物用作食物。这是这两个死亡过程之间的相互作用，以及蓝细菌所发展的防御机制，这是该研究项目的重点。我们最近观察到，与未感染的培养物相比，被病毒感染的海洋合作菌株更容易受到放牧。对捕食噬菌体感染的细胞的这种独特的偏爱具有潜在的重要生态意义，因为它通过在破裂之前去除感染细胞来干扰噬菌体增殖，因此可以间接减少噬菌体丰度。目前尚不清楚什么决定了猎物细胞的可口性。细胞表面特性可能起作用，我们有初步的证据表明细胞壁的脂多糖（LPS）成分在这方面至关重要。因此，该提案将比较以病毒感染，未感染和LPS修饰的链球菌菌株为食的原生物，以特别阐明LPS在猎物消化率中的作用。 Moreover, we will extend our studies to the Atlantic Ocean to investigate whether cultured protists graze differentially on natural Synechococcus populations, and in so doing establish the role of strain selectivity, or preference for cyanophage-infected cells, in this processOverall, the project will provide fundamentally new mechanistic information on the major biological loss processes that dictate the growth rate and yield of a key marine photoautotroph, information which is critical for defining and understanding controls on海洋光合作用。

项目成果

Targeted genomics of flow cytometrically sorted cultured and uncultured microbial groups.

通过流式细胞术分类的培养和未培养微生物群的靶向基因组学。

• DOI: 10.1007/978-1-62703-712-9_16
• 发表时间: 2014
• 期刊: Methods in molecular biology (Clifton, N.J.)
• 作者: Mazard S