Hunter Ryan C, Beveridge Terry J
Department of Molecular & Cellular Biology, College of Biological Science, University of Guelph, Ontario, Canada.
J Bacteriol. 2005 Nov;187(22):7619-30. doi: 10.1128/JB.187.22.7619-7630.2005.
High-pressure freeze-substitution and transmission electron microscopy have been used for high-resolution imaging of the natural structure of a gram-negative biofilm. Unlike more conventional embedding techniques, this method confirms many of the observations seen by confocal microscopy but with finer structural detail. It further reveals that there is a structural complexity to biofilms at both the cellular and extracellular matrix levels that has not been seen before. Different domains of healthy and lysed cells exist randomly dispersed within a single biofilm as well as different structural organizations of exopolymers. Particulate matter is suspended within this network of fibers and appears to be an integral part of the exopolymeric substance (EPS). O-side chains extending from the outer membrane are integrated into EPS polymers so as to form a continuum. Together, the results support the concept of physical microenvironments within biofilms and show a complexity that was hitherto unknown.
高压冷冻置换和透射电子显微镜已用于革兰氏阴性生物膜自然结构的高分辨率成像。与更传统的包埋技术不同，该方法证实了共聚焦显微镜所观察到的许多现象，但具有更精细的结构细节。它进一步揭示了生物膜在细胞和细胞外基质水平上存在前所未见的结构复杂性。健康细胞和裂解细胞的不同区域随机分散在单个生物膜内，同时也存在胞外聚合物的不同结构组织。颗粒物悬浮在这个纤维网络中，似乎是胞外聚合物物质（EPS）不可或缺的一部分。从外膜延伸出的O侧链整合到EPS聚合物中，从而形成一个连续体。这些结果共同支持了生物膜内物理微环境的概念，并显示出一种迄今未知的复杂性。
