Myxobacteria produce outer membrane-enclosed tubes in unstructured environments.
Myxobacteria produce outer membrane-enclosed tubes in unstructured environments.
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粘细菌在非结构化环境中产生外膜封闭的管。
DOI：
10.1128/jb.00850-13
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发表时间：
2014
影响因子：
3.2
通讯作者：
Wall,Daniel
中科院分区：
文献类型：
--
作者：
Wei,Xueming;Vassallo,ChristopherN;Pathak,DarshankumarT;Wall,Daniel
粘细菌是表现出复杂的多细胞行为的社会微生物。通过使用荧光报告基因，我们发现黄粘球菌分离株产生细长的细丝，这些细丝被外膜 (OM) 包围并含有蛋白质。我们发现，当细胞置于液体培养基或缓冲液中而不搅拌时，这些 OM 管 (OMT) 结构的产生量惊人地高。 OMT 可以很长，很容易超过多个单元长度。当通过透射电子显微镜观察时，它们的形态在管状结构和链状结构之间变化。还发现了类似中间的结构，表明 OMT 可能在这两种形态类型之间转变。为了支持这一点，视频落射荧光显微镜发现溶液中的 OMT 会动态扭曲和抖动。在坚硬的表面上，粘细菌会滑动，并且在细胞与细胞接触时，它们可以通过 TraAB 依赖性机制有效地交换其 OM 蛋白和脂质。尽管 OMT 的结构暗示了其可能充当交换渠道的角色，但事实却恰恰相反。例如，当细胞在液体培养基中生长时，主动脉内突变体会产生大量的OMT，但在这些条件下不能发生转移。因此，促进 OMT 产生的遗传和环境条件与 OM 交换不一致。
Myxobacteria are social microbes that exhibit complex multicellular behaviors. By use of fluorescent reporters, we show that Myxococcus xanthus isolates produce long narrow filaments that are enclosed by the outer membrane (OM) and contain proteins. We show that these OM tube (OMT) structures are produced at surprisingly high levels when cells are placed in liquid medium or buffer without agitation. OMTs can be long and easily exceed multiple cell lengths. When viewed by transmission electron microscopy, their morphology varies between tubes and chain-like structures. Intermediate-like structures are also found, suggesting that OMTs may transition between these two morphotypes. In support of this, video epifluorescence microscopy found that OMTs in solution dynamically twist and jiggle. On hard surfaces, myxobacteria glide, and upon cell-cell contact, they can efficiently exchange their OM proteins and lipids by a TraAB-dependent mechanism. Although the structure of OMTs hints at a possible role as conduits for exchange, evidence is presented to the contrary. For example, abundant OMT production occurs intraAortraBmutants and when cells are grown in liquid medium, yet transfer cannot occur under these conditions. Thus, genetic and environmental conditions that promote OMT production are incongruent with OM exchange.