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Research on the Regulation of Virulence by Cell-Cell Signaling in Pathogenic Bacteria

病原菌细胞间信号传导调节毒力的研究

基本信息

批准号：
15390140
负责人：
SHIMIZU Tohru
金额：
$ 9.22万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15390140/
关键词：
Clostridium perfringens DNA microarray cell-cell signaling virulence gene regulation

项目摘要

We investigated the amino acid sequence of the vapABC genes encoding a cell-cell signaling function of Clostridium perfringens, and tried to identify the gene directly involved in the production of signal substance. We found that the amino acid sequence in the signal peptide region of vapB was quite similar to those of the peptide pheromones of other bacteria. Although peptides of 4 to 20 amino acids were synthesized based on the sequence of the VapB signal region and the synthetic peptides were added to the cultures of C.perfringens, any significant activities were not detected, suggesting that the signaling peptide might be modified. However, since the vapABC mutant of C.peifringens lacked the ability to produce the signaling molecule, we assume that the genes are involved in the synthesis of the signal molecule and are analyzing further.We also investigated the global regulation of all genomic genes by a cell-cell communication with other bacteria by using DNA microarrays. Escherichia coli was co-cultured with C.perfringens and the effect of the cell-cell interaction on the expression of the genes in C.perfringens was analyzed on DNA microarays. However, the experiments were turned out to fail because the background signal was too high to analyze further. Some inhibitory substances might be present in the mixed culture, which made the background high in the experiments. Now we are trying to improve the experimental condition and are going to analyze the cell-cell interactions.We tried to investigate host factors that influence the expression of C.perfringens genes by using human and horse serum. Many genes that influenced by the addition of human serum but not by horse serum were identified by DNA microarray analysis. Among these genes, virulence genes such as sialidase were included, suggesting some factors in human serum might regulate the expression of virulence in C.perfringens.

我们研究了编码产气荚膜梭菌细胞间信号传导功能的vapABC基因的氨基酸序列，并试图鉴定直接参与信号物质产生的基因。我们发现vapB的信号肽区的氨基酸序列与其他细菌的肽信息素非常相似。尽管基于VapB信号区的序列合成了4至20个氨基酸的肽，并且将合成肽添加到产气荚膜梭菌的培养物中，但未检测到任何显著的活性，表明信号肽可能被修饰。但是，由于培氏梭菌的vapABC突变体缺乏产生信号分子的能力，我们推测这些基因参与了信号分子的合成，正在进一步分析。我们还利用DNA微阵列研究了所有基因组基因通过与其他细菌的细胞间通讯进行的全局调控。将大肠杆菌与产气荚膜梭菌共培养，并在DNA微阵列上分析细胞-细胞相互作用对产气荚膜梭菌中基因表达的影响。然而，由于背景信号太高而无法进一步分析，实验失败了。混合培养物中可能存在一些抑制物质，使实验中本底偏高。本研究通过对实验条件的改进和细胞间相互作用的分析，尝试以人血清和马血清为材料，研究宿主因素对产气荚膜梭菌基因表达的影响。通过基因芯片分析，发现了许多受人血清影响而不受马血清影响的基因。在这些基因中，包括毒力基因，如唾液酸酶，表明在人血清中的一些因素可能调节产气荚膜梭菌的毒力的表达。