HOST INDUCED BACTERIAL SURFACE MODIFICATION

宿主诱导的细菌表面修饰

• 批准号: 2665110
• 负责人: KENNETH D NOEL
• 金额: $ 10.35万
• 依托单位: MARQUETTE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-01 至 2002-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2665110
• 关键词: Leguminoseae; Rhizobiaceae; bacterial antigens; carbohydrate structure; gene mutation; lipid structure; lipopolysaccharides; mass spectrometry; mutant; nuclear magnetic resonance spectroscopy; nucleic acid sequence; symbiosis

DESCRIPTION: Rhizobium etli enters into a symbiosis with Phaseolus vulgaris. Studies with R. etli mutants have shown that the lipopolysaccharide (LPS) O-antigen of the microsymbiont is required for infection of the host. In recent years, it has been found that compounds exuded by the host trigger a structural modification of the O-antigen that can be detected with monoclonal antibodies. One of the goals of the proposed research is to identify the actual chemical change(s) in the modified structure. Wild-type LPS will be purified from cultures grown under the inducing conditions and its structure compared to LPS form uninduced wild type. The analyses will include sugar and lipid compositions and various types of mass spectral and nuclear magnetic resonance techniques. With a recently developed mutant screen, bacterial mutants that do not appear to undergo this modification have been isolated. The second goal is to use this screen to isolate more mutants of this type. Four mutants isolated in this way are also defective in host infection. A third goal is to analyze the structure of the LPS of two of these mutants to test whether they differ from the wild type LPS under noninducing conditions or only under inducing conditions. If the latter is the case, a given mutant is likely to be altered in an enzymatic activity regulated in response to the plant signal or altered in the signal transducing regulatory mechanism. Regardless of whether the difference is limited to inducing conditions, determining the structural difference is important because it would identify a type of structural specificity that has been difficult to uncover in the study of LPS functions in bacterial-host interactions. Three of the mutations found by the mutant screen are located within a relatively short stretch of DNA. Sequencing of this stretch will commence in order to define its structure, including the number of genes and their organization into transcriptional units. The importance of this work would be to establish the existence of structurally-specific roles of the LPS in a biological system that is relatively easy to study and manipulate, and which, because of the wealth of information accumulating about it worldwide, is becoming an important model in microbe-host interactions.

描述：根瘤菌与菜豆形成共生关系 寻常的。 对 R. etli 突变体的研究表明 微共生体的脂多糖 (LPS) O 抗原是 宿主的感染。 近年来，人们发现化合物 宿主分泌的 O 抗原会引发结构修饰， 可以用单克隆抗体检测。 该组织的目标之一是 拟议的研究是为了确定实际的化学变化 修改后的结构。 野生型 LPS 将从生长的培养物中纯化 诱导条件及其与LPS形式的结构比较 未诱导的野生型。 分析将包括糖和脂质成分 以及各类质谱和核磁共振 技术。 通过最近开发的突变体筛选，细菌突变体 似乎没有经过这种修改已被隔离。 第二个 目标是使用此筛选来分离更多此类突变体。 四 以这种方式分离的突变体在宿主感染方面也存在缺陷。 第三个 目标是分析其中两个突变体的 LPS 结构以进行测试 它们是否与非诱导条件下的野生型 LPS 不同，或者 仅在诱导条件下。 如果是后者，则给定的突变体 可能会改变响应调节的酶活性 植物信号或信号转导调节机制的改变。 无论差异是否仅限于诱发条件， 确定结构差异很重要，因为它可以识别 一种在结构中很难发现的特殊性 LPS 在细菌-宿主相互作用中的功能研究。 其中三个 突变体筛选发现的突变位于相对较短的时间内 DNA 的延伸。 将开始对该延伸进行排序，以便定义 它的结构，包括基因的数量及其组织 转录单位。 这项工作的重要性在于建立 LPS 在生物体内的结构特异性作用的存在 相对容易研究和操作的系统，因为 全球范围内积累的大量信息正在成为一种 微生物与宿主相互作用的重要模型。

项目成果

Genetic basis for Rhizobium etli CE3 O-antigen O-methylated residues that vary according to growth conditions.

根瘤菌 CE3 O-抗原 O-甲基化残基的遗传基础根据生长条件而变化。

• DOI: 10.1128/jb.01154-09
• 发表时间: 2010
• 期刊: Journal of bacteriology
• 影响因子: 3.2
• 作者: Ojeda,KristyleaJ;Box,JodieM;Noel,KDale
• 通讯作者: Noel,KDale