The aim of this work was to assess the adaptation of bacterial communities to environmental transitions from labile to refractory substrates. This involved testing the hypothesis that bacteria self-organize and propagate not only as individual cellular systems, but also as functional sets of interacting organisms. A biofilm community was cultivated in a flow-cell irrigated with tryptic soy broth and subjected to a cyclic series of environmental transitions, from labile to refractory substrates, followed by a period of starvation (30 days). The appearance and disappearance of specific colony morphotypes when the emigrants were plated onto tryptic soy agar was used to monitor the restructuring of the community. Confocal laser microscopy of flow cells showed that these transitions decreased the biofilm thickness and coverage. Substrate shifts also changed the architecture of the biofilm communities. Repeated inoculation of flow-cell communities with a composite inoculum increased the number and diversity of emigrants. Their biofilms were thicker and covered a wider area than those of communities that had been inoculated only at the beginning of the experiment. With repeated inoculation, the time required for the community to restructure and stabilize decreased during most transitions. This suggested that organismal recombination acted as a mechanism of adaptation, enhancing the growth of microbial communities exposed to environmental stresses. Changes in the profiles of emigrants during the adaptation of biofilm communities to environmental transitions showed the appearance and disappearance of discrete sets of organisms. This suggested that the biofilm communities responded to environmental stresses as sets of interacting organisms. Enhanced growth of biofilm communities due to repeated environmental cycling suggested that the functionality of cellular positioning accrued from one cycle to the next and was thus heritable, although it was not necessarily genetically encoded.

中文翻译：

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细菌群落适应从不稳定底物到难处理底物的环境转变。

这项工作的目的是评估细菌群落对从不稳定基质到难熔基质的环境转变的适应性。这涉及检验以下假设：细菌不仅可以作为单个细胞系统而且可以作为相互作用生物的功能集进行自我组织和繁殖。在用胰蛋白so大豆肉汤灌溉的流通池中培养生物膜群落，并经历一系列循环的环境转变，从不稳定的基质到难处理的基质，接着是饥饿期（30天）。当将移出物接种到胰蛋白酶大豆琼脂上时，特定菌落形态的出现和消失被用来监测群落的重组。流动池的共聚焦激光显微镜显示，这些转变降低了生物膜的厚度和覆盖范围。底物的变化也改变了生物膜群落的结构。用复合接种物反复接种流动细胞群落增加了移民的数量和多样性。与仅在实验开始时进行接种的社区相比，它们的生物膜更厚，覆盖的面积更大。通过反复接种，在大多数过渡期间，社区重建和稳定所需的时间减少了。这表明生物重组是一种适应机制，可增强暴露于环境压力下的微生物群落的生长。在生物膜群落适应环境转变过程中，移民特征的变化表明了离散生物的出现和消失。这表明生物膜群落作为一组相互作用的生物对环境压力作出反应。由于反复的环境循环，生物膜群落的生长增强，这表明细胞定位的功能是从一个循环到下一循环，因此是可遗传的，尽管它不一定是基因编码的。