Proteorhodopsins in Southern Ocean Bacteria

Metadata record for data from AAS Project 3127
See the link below for public details on this project.

Bacteria in marine environments have been found to be able to partially support growth by using light to generate energy in a non-photosynthetic process. This is possible due to a special protein called proteorhodopsin. It is hypothesised that formation of proteorhodopsin has evolved to cope with extreme lack of nutrients. The goal is to determine the significance of proteorhodopsins in the productivity of Southern Ocean microbial communities. This includes determination of proteorhodopsin distribution, presence in seawater and sea-ice samples using molecular techniques, and determination of how important environmental factors (light, nutrient availability, temperature) may drive its synthesis and activity.

Taken from the 2009-2010 Progress Report

Project objectives:
1. Determine incidence of proteorhodopsins in Southern Ocean water and sea-ice derived bacteria (Year 1) and other Antarctic aquatic environments (Year 2 and 3).

2. Determine whether proteorhodopsins contribute to food web energy budgets.

3. Determine how proteorhodopsin contributions are influenced by physicochemical features of the environment including light availability, temperature and nutrients.

Progress against objectives:
Proteorhodopsin is a light harvesting membrane protein that has been found recently to occur in 30-70% of marine bacterial cells. The role of this protein is uncertain but believed to be highly important in energy and nutrient budgets in food webs as it is capable of generating a proton gradient. Amongst a cultured set of Antarctic bacteria we have discovered many PR-producing species. These include many Antarctic lake species. Research is ongoing to determine affect of light on the physiology of these bacteria in particular the genome sequenced species Psychroflexus torquis, an extremely cold-adapted resident of Antarctic sea-ice.

1. Completed screen of Antarctic bacterial collection for proteorhodopsin (PR) genes using PCR-based approaches
2. Proteomic-based analysis of PR-bearing sea-ice species Psychroflexus torquis is currently ongoing
3. Light/dark defined growth-based experiments determining conditions leading to biomass enhancement are ongoing

数据元记录 源自AAS 3127号项目。本项目的公开详情见下方链接。

海洋环境中的细菌已被证实可通过非光合过程利用光能产生能量，以此部分维持自身生长。这一现象依托于一类被称为视紫红质蛋白（proteorhodopsin）的特殊蛋白质。有假说提出，视紫红质蛋白的演化形成是为了应对极端营养匮乏的环境。本项目旨在探明视紫红质蛋白在南大洋微生物群落生产力中的重要性，具体研究内容包括：运用分子技术检测视紫红质蛋白在海水及海冰样本中的分布与存在情况，以及明确光照、营养可获得性、温度等环境因子如何调控其合成与活性。

本内容节选自2009-2010年度项目进展报告。

项目目标：
1. 检测南大洋水体及海冰来源细菌（第1年）与其他南极水生环境（第2、3年）中视紫红质蛋白的检出率。
2. 探明视紫红质蛋白是否对食物网能量收支存在贡献。
3. 明确环境物理化学特征（包括光照可获得性、温度与营养水平）如何影响视紫红质蛋白的功能贡献。

项目目标完成进展：
视紫红质蛋白是一种光捕获膜蛋白，近期研究发现其在30%~70%的海洋细菌细胞中存在。该蛋白的具体功能尚未明确，但被认为在食物网的能量与营养收支中发挥关键作用，因其可介导质子梯度的形成。在已培养的南极细菌菌株中，我们已发现多种可产生视紫红质蛋白的物种，其中不乏南极湖泊来源的菌株。目前针对这类细菌（尤其是已完成全基因组测序的南极海冰极端适冷常驻菌株冰栖冷弯杆菌（Psychroflexus torquis））的光照对其生理影响的研究正在进行中。

1. 已基于聚合酶链式反应（PCR）技术完成南极细菌菌株库的视紫红质蛋白（PR）基因筛查
2. 针对携带视紫红质蛋白的海冰菌株冰栖冷弯杆菌的蛋白质组学分析目前正在进行中
3. 旨在明确可促进菌体生物量提升的光照/黑暗培养条件的生长实验正在开展