Gallegos-Monterrosa Ramses, Mhatre Eisha, Kovács Ákos T
Terrestrial Biofilms Group, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany.
Microbiology (Reading). 2016 Nov;162(11):1922-1932. doi: 10.1099/mic.0.000371. Epub 2016 Sep 13.
Bacillus subtilis is an intensively studied Gram-positive bacterium that has become one of the models for biofilm development. B. subtilis 168 is a well-known domesticated strain that has been suggested to be deficient in robust biofilm formation. Moreover, the diversity of available B. subtilis laboratory strains and their derivatives have made it difficult to compare independent studies related to biofilm formation. Here, we analysed numerous 168 stocks from multiple laboratories for their ability to develop biofilms in different set-ups and media. We report a wide variation among the biofilm-forming capabilities of diverse stocks of B. subtilis 168, both in architecturally complex colonies and liquid-air interface pellicles, as well as during plant root colonization. Some 168 variants are indeed unable to develop robust biofilm structures, while others do so as efficiently as the non-domesticated NCIB 3610 strain. In all cases studied, the addition of glucose to the medium dramatically improved biofilm development of the laboratory strains. Furthermore, the expression of biofilm matrix component operons, epsA-O and tapA-sipW-tasA, was monitored during colony biofilm formation. We found a lack of direct correlation between the expression of these genes and the complexity of wrinkles in colony biofilms. However, the presence of a single mutation in the exopolysaccharide-related gene epsC correlates with the ability of the stocks tested to form architecturally complex colonies and pellicles, and to colonize plant roots.
枯草芽孢杆菌是一种经过深入研究的革兰氏阳性细菌，已成为生物膜形成的模型之一。枯草芽孢杆菌168是一种著名的驯化菌株，有人认为它在形成强大生物膜方面存在缺陷。此外，现有的枯草芽孢杆菌实验室菌株及其衍生物的多样性使得难以比较与生物膜形成相关的独立研究。在这里，我们分析了来自多个实验室的大量168菌株在不同设置和培养基中形成生物膜的能力。我们报告了枯草芽孢杆菌168不同菌株在形成生物膜能力方面存在广泛差异，无论是在结构复杂的菌落和液-气界面菌膜中，还是在植物根部定殖过程中。一些168变体确实无法形成强大的生物膜结构，而其他变体形成生物膜的效率与未驯化的NCIB 3610菌株一样高。在所研究的所有情况下，向培养基中添加葡萄糖显著改善了实验室菌株的生物膜形成。此外，在菌落生物膜形成过程中监测了生物膜基质成分操纵子epsA-O和tapA-sipW-tasA的表达。我们发现这些基因的表达与菌落生物膜皱纹的复杂性之间缺乏直接相关性。然而，胞外多糖相关基因epsC中单个突变的存在与所测试菌株形成结构复杂的菌落和菌膜以及在植物根部定殖的能力相关。
