SPORE PEPTIDOGLYCAN DEGRADATION IN BACILLUS ANTHRACIS

描述（由申请人提供）：炭疽中的感染因子是休眠的B。炭疽孢子，并且感染的建立需要孢子的萌发和生长。孢子皮层肽聚糖壁在萌发过程中的降解是必要的，以允许孢子核心中的再水合和恢复代谢。皮层裂解酶以非活性形式存在于孢子中，并且仅在特定萌发分子存在下被激活。拟议研究的目标是确定重要的B。炭疽皮层裂解酶，其活动的特点，并了解其激活机制。在B中发现的肽聚糖的结构。测定炭疽菌休眠和萌发孢子，以鉴定在萌发过程中起作用的皮层裂解活性。基于序列相似性，预测编码皮层裂解酶的基因将被破坏，突变株中发芽裂解活性的变化将被表征。将从萌发的B中提取和纯化皮层裂解酶。炭疽孢子这些蛋白质的酶活性和身份将被确定。对孢子皮层裂解过程的更深入了解将为在两个方面对抗炭疽感染提出可能的方法。鉴定阻断皮层溶解的药物或治疗将允许治疗暴露于孢子的个体以防止感染的建立。确定激活皮层溶解的化学品或处理方法，导致萌发并使孢子对标准杀菌剂敏感，将使孢子污染部位更容易去污并防止人类接触。

DESCRIPTION (provided by applicant): The infectious agent in anthrax is the dormant B. anthracis spore, and establishment of infection requires germination and outgrowth of the spore. Degradation of the spore cortex peptidoglycan wall during germination is necessary to allow rehydration and resumption of metabolism in the spore core. Cortex lytic enzymes are present in an inactive form in the spore and are activated only in the presence of specific germinant molecules. Goals of the proposed studies are identification of the important B. anthracis cortex lytic enzymes, characterization of their activities, and understanding of the mechanisms for their activation. Structures of the peptidoglycan found in B. anthracis dormant and germinating spores will be determined in order to identify cortex lytic activities operating during germination. Genes predicted to encode cortex lytic enzymes, based upon sequence similarities, will be disrupted and changes in germination lytic activities in the mutant strains will be characterized. Cortex lytic enzymes will be extracted and purified from germinating B. anthracis spores. The enzymatic activities and identities of these proteins will be determined. A greater understanding of the process of spore cortex lysis will suggest possible methods for combating anthrax infection on two fronts. Identification of drugs or treatments that block cortex lysis will allow treatment of individuals exposed to spores to prevent establishment of infection. Identification of chemicals or treatments that activate cortex lysis, resulting in germination and rendering the spores susceptible to standard bactericidal agents, will allow easier decontamination of spore-contaminated sites and prevention of human exposure.