Genetic Analysis of Mycobacterial Biofilm Formation

描述(由申请人提供)：鸟分枝杆菌复合体(MAC)是在易感人类中引起疾病的最重要的环境分枝杆菌。大多数MAC感染被认为来自稳定殖民的饮用水供应。细菌在水中的主要生活方式是在表面附着的生物膜中生长，最近的研究表明MAC也不例外。它大量存在于取自供水系统的生物膜样本中，而且似乎是这种环境中的优势分枝杆菌物种。遗传方法已经被用来分析快速生长的模式物种污垢分枝杆菌的生物膜形成；然而，MAC生物膜形成的遗传学仍有待探索。利用新开发的遗传和基因组工具，结合真实的MAC生物膜发育实验室模型，我们将进行第一次这样的调查。这个探索性项目的具体目标是：1)通过一种新的转座体诱变方法鉴定参与生物膜形成早期阶段的MAC基因；2)通过信号标记突变和转座子位点杂交鉴定参与成熟两种生物膜形成的MAC基因。通过建立MAC对生物膜形成的遗传分析的方法和条件，我们将开始阐明分枝杆菌生物学几乎完全没有特征的一个方面。这些结果将提高我们对环境分枝杆菌微生物生态学的理解，并可能导致改进保护易感人群免受MAC感染的方法。

DESCRIPTION (provided by applicant): The Mycobacterium avium complex (MAC) is the most significant of the environmental mycobacteria that cause disease in susceptible humans. Most MAC infections are thought to come from stably colonized drinking water supplies. The predominant way of life for bacteria in water is growth in surface-adherent biofilms, and recent studies have shown that MAC is no exception. It is present in vast numbers in biofilm samples taken from water distribution systems, and it appears to be the dominant Mycobacterium species in such environments. Genetic approaches have been used to analyze biofilm formation by the fast-growing model species M. smegmatis; however the genetics of biofilm formation by MAC remains to be explored. Using newly developed genetic and genomic tools, combined with authentic laboratory models of MAC biofilm development, we will conduct the first such investigation. The specific aims of this exploratory project are 1) to identify MAC genes involved in the early stages of biofilm formation by using a novel "transposome" mutagenesis approach, and 2) to identify MAC genes involved in the formation of mature two-species biofilms by using signature-tagged mutagenesis and transposon site hybridization. By establishing methods and conditions for genetic analysis of biofilm formation by MAC, we will begin to shed light on an aspect of mycobacterial biology that is almost entirely uncharacterized. The results will improve our understanding of the microbial ecology of environmental mycobacteria, and they may lead to improved methods for protecting susceptible people from MAC infection.