Relation of capsular polysaccharide production and colonial cell organization to colony morphology in Vibrio parahaemolyticus
Relation of capsular polysaccharide production and colonial cell organization to colony morphology in Vibrio parahaemolyticus
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DOI：
10.1128/jb.182.19.5513-5520.2000
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发表时间：
2000-10-01
影响因子：
3.2
通讯作者：
McCarter, LL
中科院分区：
文献类型：
--
作者：
Enos-Berlage, JL;McCarter, LL
副溶血性弧菌是一种普遍存在的革兰氏阴性海洋细菌，其菌落形态在不透明和半透明之间发生阶段性变化。本研究旨在确定导致不透明和半透明表型的因素，并检查两种集落类型内的细胞组织。通过电子显微镜检查钌红染色的细菌细胞的薄切片，发现在半透明菌株的制备物中不存在的不透明细胞周围有厚的电子致密层。从不透明和半透明菌株中提取胞外多糖（EPS）材料，并且不透明菌株显示出产生丰富水平的多糖，与半透明菌株相反。EPS的组成分析确定了四种主要糖：葡萄糖、半乳糖、岩藻糖和N-乙酰葡糖胺。共聚焦扫描激光显微镜用于研究不透明和半透明集落内的细胞组织。两种类型的集落内的细胞均表现出显著的组织结构;杆状细胞在整个殖民地的深度上彼此平行并垂直于琼脂表面排列。半透明集落中的细胞比不透明集落中的细胞排列更紧密。此外，观察到这两种菌落类型的结构完整性存在显著差异。当集落被扰动时，半透明集落的细胞组织被完全破坏，而不透明集落的组织被保持。据我们所知，这项研究首次描述了细胞是如何在一个有活力的细菌菌落内部组织起来的。我们认为不透明菌株产生的大量EPS填充了殖民地内的细胞间隙，导致结构完整性增加和不透明表型。
Vibrio parahaemolyticus is a ubiquitous, gram-negative marine bacterium that undergoes phase variation between opaque and translucent colony morphologies. The purpose of this study was to determine the factor(s) responsible for the opaque and translucent phenotypes and to examine cell organization within both colony types. Examination of thin sections of ruthenium red-stained bacterial cells by electron microscopy revealed a thick, electron-dense layer surrounding the opaque cells that was absent in preparations from translucent strains. Extracellular polysaccharide (EPS) material was extracted from both opaque and translucent strains, and the opaque strain was shown to produce abundant levels of polysaccharide, in contrast to the translucent strain. Compositional analysis of the EPS identified four major sugars: glucose, galactose, fucose, and N-acetylglucosamine. Confocal scanning laser microscopy was used to investigate cell organization within opaque and translucent colonies. Cells within both types of colonies exhibited striking organization; rod-shaped cells were aligned parallel to one another and perpendicular to the agar surface throughout the depth of the colony. Cells within translucent colonies appeared more tightly packed than cells in opaque colonies. In addition, a dramatic difference in the structural integrity of these two colony types was observed. When colonies were perturbed, the cell organization of the translucent colonies was completely disrupted while the organization of the opaque colonies was maintained. To our knowledge, this study represents the first description of how cells are organized in the interior of a viable bacterial colony. We propose that the copious amount of EPS produced by the opaque strain fills the intercellular space within the colony, resulting in increased structural integrity and the opaque phenotype.