Biofilm formation is a strategy of many bacterial species to adapt to a variety of stresses and has become a part of infections, contaminations, or beneficial interactions. In this study, we demonstrate that profound physiological changes permit Bacillus cereus to switch from a floating to a sessile lifestyle, to undergo further maturation of the biofilm and to differentiate into the offensive or defensive features. We report that floating and biofilm cells are populations that differentiate metabolically, with members of each subpopulation developing different branches of certain metabolic pathways. Secondly, biofilm populations rearrange nucleotides, sugars, amino acids, and energy metabolism. Thirdly, this metabolic rearrangement coexists with: the synthesis of the extracellular matrix, sporulation, reinforcement of the cell wall, activation of the ROS detoxification machinery and production of secondary metabolites. This strategy contributes to defend biofilm cells from competitors. However, floating cells maintain a fermentative metabolic status that ensures a higher aggressiveness against hosts, evidenced by the production of toxins. The maintenance of the two distinct subpopulations is an effective strategy to face different environmental conditions found in the life styles of B. cereus.

中文翻译：

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生物膜的形成显示蜡样芽孢杆菌固有的进攻和防御特征。

生物膜形成是许多细菌物种适应各种压力的一种策略，已成为感染，污染或有益相互作用的一部分。在这项研究中，我们证明了深刻的生理变化允许蜡样芽胞杆菌从漂浮型转变为无柄型生活方式，使其生物膜进一步成熟并分化为进攻性或防御性特征。我们报告说，漂浮和生物膜细胞是可以区别代谢的种群，每个亚群的成员发育某些代谢途径的不同分支。其次，生物膜种群重新排列核苷酸，糖，氨基酸和能量代谢。第三，这种代谢重排与以下各项共存：细胞外基质的合成，孢子形成，细胞壁增强，激活ROS解毒机制并产生次级代谢产物。该策略有助于防御竞争对手的生物膜细胞。但是，漂浮细胞保持发酵代谢状态，从而确保对宿主的更高侵略性，这是由毒素产生所证明的。维持两个不同亚群是面对蜡状芽孢杆菌生活方式中发现的不同环境条件的有效策略。