Fatty Acid Regulation in a Deep-Sea Bacterium

9630546 Bartlett这项研究的目的是鉴定和鉴定深海细菌光细菌菌株SS9中与压力敏感和高压适应有关的基因。遗传研究表明，多不饱和脂肪酸物种All-cis-5，8，11，14，17-EPA的丰度、高压适应和外膜蛋白(OMP)基因表达的压力调节之间存在联系。本研究试图确定EPA是否是SS9中高压适应所必需的，并区分两种调节可能性：第一，EPA很可能通过对膜的物理状态的影响，影响压力敏感和OMP基因调节；第二，一个共同的全球调节因子控制编码压力可调节的OMP基因的表达和影响EPA丰度的基因。导致OMP基因表达、EPA丰度和高压生长能力降低的突变将在现有的SS9突变株EC1002中得到表征，并将阐明EC1002假逆变株高压适应的遗传基础。还将获得在合成不饱和脂肪酸(UFAs)方面缺乏的突变体，并对其进行鉴定。不饱和脂肪酸在高压生长和压力调控基因表达中的作用将被阐明。将研究高压或低温对不饱和脂肪酸基因的可能调控。最后，对所有SS9不饱和脂肪酸突变体和EC1002菌株耐高压衍生物制备的脂类分散体的膜流动性进行了测定。机械感受器是所有生物体的一种常见的感觉方式。这些实验将提供对脂肪酸在细胞对机械刺激的反应信号中可能扮演的角色的洞察。它们还将提供基因和生化适应方面的信息，使深海环境中的生命成为可能。最后，该项目将导致分离与EPA生物合成有关的基因，这可能会在以后为利用重组DNA技术为生物技术大量生产EPA提供手段。环境保护局的短期需求是作为水产养殖和家禽养殖的食品补充剂。从长远来看，EPA需要作为人类的膳食补充剂，在这种情况下，它已被证明在人类营养方面具有重要意义。***

9630546 Bartlett The objective of this investigation is to identify and characterize genes involved in pressure sensing and high pressure adaptation in the deep-sea bacterium Photobacterum species strain SS9. Genetic studies in this organism indicate that a link exists between the abundance of the polyunsaturated fatty acid species all-cis-5, 8, 11, 14, 17-eicosapentaenoic acid (EPA), high pressure adaptation, and the pressure regulation of outer membrane protein (OMP) gene expression. This research seeks to establish whether EPA is required for high pressure adaptation in SS9 and to distinguish between 2 regulatory possibilities; first that EPA, most likely through effects on the physical state of the membrane, influences pressure-sensing and omp gene regulation, or second, that a common global regulatory factor controls the expression of genes encoding pressure-regulatable OMPs and those which influence EPA abundance. The mutation responsible for decreased omp gene expression, EPA abundance, and high pressure growth ability will be characterized in the existing SS9 mutant strain EC1002, and the genetic basis for high pressure adaption in pseudorevertants of strain EC1002 will also be elucidated. Additional mutants deficient in the synthesis of unsaturated fatty acids (UFAs) will be obtained and characterized. The role of UFAs in high pressure growth and pressure-regulated gene expression will be clarified. Possible UFA gene regulation by high pressure or cold temperature will be investigated. Finally, the membrane fluidity of lipid dispersions prepared form all SS9 UFA mutants and high pressure resistant derivatives of strain EC1002 will be measured. %%% Mechanoreception is a common sensory modality in all organisms. These experiments will provide insight into the possible role played by fatty acids in signalling a cellular response to a mechanical stimulus. They will also provide information into genetic and biochemical adaptations which make life possible in deep-sea e nvironments. Finally, the project will result in the isolation of genes involved in EPA biosynthesis which could later provide the means for using recombinant DNA technologies to overproduce EPA for biotechnology. The short term need for EPA is as a food supplement in aquaculture and poultry farming. In the longer term EPA is needed as a dietary supplement for humans in which case it has been shown to be of major importance in human nutrition. ***