ELECTRON MICROSCOPY OF MYXOCOCCUS XANTHUS BIOFILMS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 尽管大多数细菌生长在自然和致病生态系统的生物膜中，但人们对其组成细胞的超微结构或其群落结构的细节知之甚少。我们采用了高压冷冻和冷冻替代，最大限度地减少了化学固定、样品聚集和样品提取的伪影。作为进一步的创新，我们首次在生物膜研究中使用了电子断层扫描和三维(3D)可视化来更好地解析生物膜的大分子3D超微结构。这种精湛的标本制备和在z轴上极大提高的分辨率相结合，为研究黄色粘球菌细胞超微结构和生物膜群落结构打开了一扇窗。介绍了生物膜基质中染色质小体、细胞质的组织结构、相邻细胞之间的膜结合以及菌毛和囊泡的结构和分布等新的结构信息。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Despite the fact that most bacteria grow in biofilms in natural and pathogenic ecosystems, very little is known about the ultrastructure of their component cells or about the details of their community architecture. We used high-pressure freezing and freeze-substitution to minimize the artifacts of chemical fixation, sample aggregation and sample extraction. As a further innovation we have, for the first time in biofilm research, used electron tomography and three-dimensional (3D) visualization to better resolve the macromolecular 3D ultrastructure of a biofilm. This combination of superb specimen preparation and greatly improved resolution in the z-axis has opened a window in studies of Myxococcus xanthus cell ultrastructure and biofilm community architecture. New structural information of the chromatin body, cytoplasmic organization, membrane apposition between adjacent cells, and structure and distribution of pili and vesicles in the biofilm matrix is presented.