PHOTOSENSITIZATION MECHANISMS IN HYPOXIC MEDIA

缺氧介质中的光敏化机制

• 批准号: 6345246
• 负责人: ROBERT W REDMOND
• 金额: $ 0.13万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2002-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6345246
• 关键词: bacteria; bioengineering /biomedical engineering; biological products; biomaterials; biomedical resource; biotechnology; infection; spectrometry; structural biology; technology /technique

Bacterial endospores derive much of their longevity and resistance properties from therelative dehydration of their protoplasts. This dehydration is maintained by a surrounding peptidoglycan structure, the spore cortex. A structural modification unique to,the spore cortex is removal of all or part of the peptide side chains from the majority of the muramic acid residues andconversion of 50% of the muramic acid to muramic lactam. A mutation in the cwLD gene of Bacillus subtilis, predicted to encode a muramoyl-L-alanine amidase, results in the production of spores containing no muramic lactam. These spores have normally dehydrated protoplasts but are unable to complete the germination/outgrowth process to produce viable cells. Our objective is a detailed understanding of formation and maintenance of a dormant, resistant bacterial (Bacillus subtilis) spore. The aims are: a) analyze the sequence, regulation and function of additional genes encoding penicillin-binding proteins (PBP); b) with strains lacking one or more PBPs, analyze the cortex structure and heat resistance of their spores; and c) identify the enzyme(s) initiating cortex hydrolysis during spore germination. Work being carried out with B. suhtilis should yield knowledge applicable to other Gram-positive spore formers. The latter organisms are significant agents of food spoilage and food-borne human disease, largely because of the resistant nature of spores. Thus knowledge gained herein could have significant applications. Muropeptide structures are determined by amino acid/amino sugar analysis and NLAJ-DI-TOF MS.

细菌内生孢子的寿命和抵抗力很大程度上来自于内生孢子 其原生质体相对脱水的特性。 这 脱水是由周围的肽聚糖结构维持的， 孢子皮层。 孢子独有的结构修饰 皮质是从皮质中去除全部或部分肽侧链 大部分胞壁酸残基和 50% 的转化率 胞壁酸转化为胞壁内酰胺。 cwLD基因突变 枯草芽孢杆菌，预计编码胞壁酰-L-丙氨酸酰胺酶， 导致产生不含胞壁内酰胺的孢子。 这些孢子通常具有脱水的原生质体，但无法脱水 完成萌芽/生长过程以产生活细胞。 我们的目标是详细了解形成和维护 休眠的耐药细菌（枯草芽孢杆菌）孢子。 目标 是： a) 分析附加的序列、调节和功能 编码青霉素结合蛋白（PBP）的基因； b) 有菌株 缺乏一种或多种 PBP，分析皮层结构和热量 其孢子的抵抗力； c) 识别引发酶 孢子萌发过程中皮层水解。 正在进行的工作 与 B. suhtilis 的研究应该会产生适用于其他疾病的知识 革兰氏阳性孢子形成者。 后者的生物体意义重大 食物腐败和食源性人类疾病的媒介，主要是因为 孢子的抗性。 因此，在此获得的知识可以 有重要的应用。 胞肽结构确定 通过氨基酸/氨基糖分析和 NLAJ-DI-TOF MS。