ToxR/S and Unsaturated Fatty Acid Regulation in Photobacterium profundum Strain SS9

深光杆菌菌株 SS9 中的 ToxR/S 和不饱和脂肪酸调节

• 批准号: 9974528
• 负责人: Douglas Bartlett
• 金额: $ 30.5万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9974528&HistoricalAwards=false
• 关键词: ToxR; Unsaturated; Fatty; Acid; Regulation

BartlettThe ToxR/S regulon is widely distributed among bacteria of the family Vibrionaceae. However, little is known about the nature or even the number of genes regulated by these proteins, except for some genes involved in human colonization and pathogenesis which have been acquired by horizontal gene transfer in Vibrio cholerae. Recent experiments in the investigator's lab indicate that ToxR and ToxS influence the ability of the deep-sea bacterium Photobacterium profundum strain SS9 to respond to changes in pressure and to grow at elevated pressure. Furthermore, in this organism, ToxR/S, together with the cyclic AMP receptor protein (CRP), appears to modulate the levels of unsaturated fatty acids (UFA's). It has previously been suggested that UFA's may be important factors in the adaptation of the membrane to elevated pressure and to decreased temperature. During this project the investigator will characterize the ToxR/S regulon in general, and the pressure and temperature regulation of UFA's in particular, in SS9. The connection between toxRS gene expression and growth inhibition at elevated pressure will be clarified. ToxR/S regulated genes will be identified using both genetic and molecular screening strategies. A subset of these genes will then be sequenced, their transcriptional regulation characterized, and their functions ascertained through mutant studies. Additional studies will specifically explore the possibility of transcriptional, translational, and posttranslational regulation of UFA's by pressure and temperature. Transcriptional regulation of genes whose products govern the levels of cis-vaccenic acid and eicosapentaenoic acid will be determined as a function of temperature and pressure in various regulatory protein mutant backgrounds. Finally, the regulation of the activity of 0-ketoacyl-ACP synthase II, which is required for high pressure and low temperature regulation of cis-vaccenic acid levels, will be examined through kinetic analyses.Despite the fact that the deep sea represents the largest part of our planet where life is found, little is known about the adaptations of organisms to this cold environment where the water pressure can exceed 15,000 pounds per square inch. In this project a bacterial species isolated from the bottom of the ocean will be used for genetic and physiological experiments to address the control of membrane components (unsaturated fatty acids) which are required for its growth and survival at low temperature and high pressure. The possibility that an enzyme responsible for making unsaturated fatty acids in this microorganism possesses unique characteristics suiting it to deep-sea conditions will be explored. The investigator will seek to identify additional cell functions which help the organism adjust to high pressure. The results will be of use in understanding the adaptation of life to extreme environments and will provide new information about how cells maintain proper membrane function.

Bartlettthe toxr/s的调节量广泛分布在家族的细菌中。然而，除了某些参与人类定植和发病机理的基因外，对这些蛋白质调节的基因的性质甚至几乎一无所知，这些基因已通过水平基因转移在Vibrio Cholerae中获得。研究者实验室的最新实验表明，毒和毒物会影响深海细菌po杆菌菌株SS9响应压力变化并在高压升高时生长的能力。此外，在这种生物体中，TOXR/S与环状AMP受体蛋白（CRP）一起似乎调节了不饱和脂肪酸（UFA）的水平。以前已经提出，UFA可能是膜适应压力升高和温度降低的重要因素。 在此项目中，研究者将表征总体上的Toxr/s调节，尤其是UFA的压力和温度调节，在SS9中。将阐明托克斯基因表达与升高压力下的生长抑制之间的联系。将使用遗传和分子筛选策略来鉴定TOXR/S调节的基因。然后将对这些基因的一个子集进行测序，其转录调节表征，并通过突变研究确定其功能。其他研究将特别探讨通过压力和温度对UFA的转录，翻译和翻译后调节的可能性。在各种调节性蛋白突变体背景下，将确定基因的转录调节，其产物控制的基因的基因和二十碳烯酸的水平将确定为温度和压力的函数。最后，将通过动力学分析来检查0-Ketoacyl-ACP合酶II的活性，这是高压和低温调节顺式 - vaccenic酸水平所必需的。尽管深海代表了我们星球上最大的一部分，但在这种情况下却几乎不知道有机体的适应性，但在这种情况下却毫无疑问。在该项目中，从海洋底部分离的细菌物种将用于遗传和生理实验，以解决其在低温和高压下生长和生存所必需的膜成分（不饱和脂肪酸）。负责这种微生物中不饱和脂肪酸的酶具有适合于深海条件的独特特征。研究人员将寻求确定帮助有机体适应高压的其他细胞功能。结果将用于理解生命对极端环境的适应，并将提供有关细胞如何保持适当膜功能的新信息。