一株分离自北极的细菌经可见光照射致死的机理

项目名称： 一株分离自北极的细菌经可见光照射致死的机理

项目编号： No.31200038

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 微生物学、植物学

项目作者： 彭方

作者单位： 武汉大学

项目金额： 23万元

中文摘要： 菌株R3-44分离自北极新奥尔松地区（北纬79 ）的表层土壤，其16S rRNA基因与几丁质单胞菌属的Chitinimonas koreensis具有最高同源性95%，是一株潜在的新分类单元，而且具有十分独特的光敏感特性。该菌株是兼性厌氧菌，菌落避光培养呈黄绿色，而光照培养呈白色，移除光照后可恢复成黄绿色。但是，培养获得的黄绿色菌体在有氧条件下进行可见光照射会导致死亡。本研究拟从光-色素-氧三个因素的角度分析其所起的作用和相互间的影响，探究菌株R3-44光致死的成因和机理。并通过对野生和白色突变菌株全基因组序列的比较和光、暗两种培养条件下野生菌的转录差异表达谱，寻找色素表达的关键基因，分析在光和暗培养条件下的代谢差异，推测色素-卟啉代谢途径的触发、关闭机制及其与北极极昼极夜环境的可能适应机理。并对菌株R3-44的色素和卟啉成分及结构进行研究，探讨其功能和作为光敏剂用于光动力学治疗的可能性。

中文关键词： 可见光；色素；卟啉；北极；几丁质单胞菌

英文摘要： Strain R3-44 isolated from the surface soil of the Arctic at Ny-Alesund area (N79 ) with the highest 16S rRNA gene sequence similarity 95% with Chitinimonas koreensisthe, a potential new taxa. The strain can grow under aerobic and anaerobic conditions, but under visible light illumination the cultures were white, dark condition, the cultures were yellow-green. The yellow-green cultures will be death during the exposure to visible light in aerobic condition. We plan to explore the killing mechanism of strain R3-44 by visible light from the role and impact of three factors: light - pigments - oxygen. Compare of the genomic sequences of the wild and white mutant strains and mine the differentially transcriptomic profile of wild strain in dark and light conditions to look for key genes of pigment expression, to analysis the metabolic differences in light- and dark-grown cultures, to conjecture the trigger and closing mechanism of the chlorophyll - porphyrin metabolic pathways and the possible adaptation to polar day to polar night. Also, the composition and structure of pigments and porphyrin extracted from strain R3-44 will be studied and to discuss its role and the possibility of as a photosensitizer for photodynamic therapy.

英文关键词： Visible light；pigment；porphyrin；Arctic；Chitinimonas