Helicobacter Pylori--Nutrition, Serum and Culturability

描述（由申请方提供）：幽门螺杆菌是一种苛养、微需氧微生物，与消化性溃疡和胃癌密切相关。该菌的生长要求只是部分确定，H.幽门螺杆菌从体内部位和环境中的感染仍然具有挑战性。H.幽门螺杆菌通常需要血液或血清用于体外生长。我们的初步实验提供了对生长和血清需求的了解，并揭示了H。通过使用部分确定的培养基而不是标准的复合培养基，显著改善了来自冷冻储存物的幽门螺杆菌。我们假设使用复合培养基抑制了休眠或氧化应激的生物体的恢复，排除了H。pylori来自环境我们建议通过进一步定义生长要求和确定血清中最主要的生长促进成分来扩展我们的初步研究。构建了H.将筛选pylori突变体以鉴定不能在无血清的限定培养基中生长的克隆。由于血清既能促进生长，又能提高培养物的存活率，因此在此筛选中鉴定出的基因有望为血清在H.幽门生长这些基因也可能在H.幽门螺杆菌，并可能影响毒力和传播的有机体以及。优化的培养基将与其他存活率测量方法结合使用，以评估H.幽门螺杆菌从诸如肠道、唾液和粪便的部位。这些研究结果将有助于加深对H.幽门螺杆菌的生长要求和相关基因，特别是与生物体从各种环境条件中恢复有关的要求。本研究将为临床和研究应用提供更有用的培养基配方，也可能适用于其他苛养菌的培养。

DESCRIPTION (provided by the applicant): Helicobacter pylori is a fastidious, microaerophilic organism strongly associated with peptic ulcers and gastric carcinoma. Growth requirements of this organism have only been partially defined, and isolation of H. pylori from in vivo sites and the environment remains challenging. H. pylori normally requires blood or serum for growth in vitro. Our preliminary experiments provide insights into growth and serum requirements and reveal that recovery of H. pylori from frozen stocks is significantly improved through the use of a partially defined medium rather than standard complex media. We hypothesize that the use of complex media inhibits recovery of dormant or oxidatively stressed organisms, precluding isolation of H. pylori from environmental sources. We propose to extend our preliminary studies by further defining growth requirements and identifying the component(s) of serum most responsible for growth augmentation. A transposon library of H. pylori mutants will be screened to identify clones which fail to grow in defined medium without serum. Since serum both augments growth and prolongs culture viability, genes identified in this screen are expected to provide clues regarding serum's function in H. pylori growth. These genes may also play a role in stationary phase survival of H. pylori and may impact virulence and transmission of the organism as well. The optimized medium will be used in conjunction with other measurements of viability to evaluate extragastric survival of H. pylori from sites such as the intestine, saliva, and feces. Results of these studies should extend the understanding of H. pylori growth requirements and the genes involved, particularly requirements relevant to recovery of the organism from various environmental conditions. This research will provide more useful media formulations for both clinical and research applications, and may also be applicable to the culture of other fastidious bacteria.