Acetone metabolism in Helicobacter pylori

幽门螺杆菌中的丙酮代谢

• 批准号: 6752150
• 负责人: Timothy Randall Hoover
• 金额: $ 7.36万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-01 至 2005-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6752150
• 关键词: Escherichia coli; Helicobacter; acetone; bacteria infection mechanism; carboxylation; decarboxylases; enteric bacteria; enzyme activity; gastric mucosa; gastrointestinal infection; gene mutation; gerbil /jird; host organism interaction; laboratory mouse; microorganism metabolism; molecular cloning

DESCRIPTION (provided by applicant): Helicobacter pylori is a major human pathogen that colonizes the gastric mucosa, leading to gastric inflammation that can progress to chronic gastritis, peptic ulcer, gastric cancer or mucosal-associated lymphoma. The ability of H. pylori to establish a chronic infection in the human stomach indicates that it is well adapted to acquire the nutrients it needs for growth in this unique environment. Complete genomic sequences for two unrelated H. pylori strains, 26695 and J99, have greatly aided the understanding of the physiology of this bacterium. Both sequenced strains were reported recently to have the genes for a potential acetone carboxylase, an enzyme that initiates the metabolism of acetone by converting it to acetoacetate. Acetone is produced in the body upon the spontaneous decarboxylation of acetoacetate, one of the ketone bodies produced by the liver and used as an energy source when glucose is not readily available. Ketones are always present in the blood, with up to 185 grams of ketone bodies produced per day by the liver of a healthy adult. This proposal will test the hypothesis that H. pylori utilizes acetone as an important energy source for the bacterium in the gastric mucosa. The first specific aim of the proposal is to verify that H. pylori has a functional acetone carboxylase by expressing the protein in Escherichia coli, purifying it, and examining its ability to catalyze the carboxylation of acetone. The second specific aim is to determine if this enzyme is needed by H. pylori to establish a chronic infection in the gastric mucosa. The operon encoding the H. pylori acetone carboxylase will be disrupted and the resulting mutant strain will be examined for its ability to colonize the stomachs of mice and Mongolian gerbils. The proposed studies will expand knowledge of metabolic pathways in H. pylori, which will lead to a better understanding of how this pathogen establishes infections in humans and may provide new strategies for the prevention or treatment of H. pylori infections.

描述（由申请方提供）：幽门螺杆菌是一种主要的人类病原体，定植于胃粘膜，导致胃炎症，可进展为慢性胃炎、消化性溃疡、胃癌或粘膜相关淋巴瘤。 H.幽门螺杆菌在人类胃中建立慢性感染表明它非常适合在这种独特的环境中获得生长所需的营养。 两个不相关的H. pylori菌株26695和J99的发现极大地帮助了对该细菌生理学的理解。 最近有报道称，这两种测序菌株都具有潜在的丙酮羧化酶基因，丙酮羧化酶是一种通过将丙酮转化为乙酰乙酸来启动丙酮代谢的酶。 丙酮是乙酰乙酸自发脱羧后在体内产生的，乙酰乙酸是肝脏产生的酮体之一，当葡萄糖不容易获得时用作能量来源。 酮总是存在于血液中，健康成人的肝脏每天产生多达185克的酮体。 这一建议将测试的假设，H。幽门螺杆菌利用丙酮作为胃粘膜中细菌的重要能量来源。 该建议的第一个具体目标是验证H。pylori中的丙酮羧化酶，通过在大肠杆菌中表达该蛋白，纯化它，并检测其催化丙酮羧化的能力。 第二个具体目标是确定这种酶是否是H. pylori以在胃粘膜中建立慢性感染。 编码H.将破坏pylori丙酮羧化酶，并检查所得突变株在小鼠和蒙古沙鼠胃中定殖的能力。 这些研究将有助于拓宽对H. pylori的研究，这将有助于更好地了解这种病原体如何在人类中建立感染，并可能为预防或治疗H.幽门感染。