Center for Microbial Ecology and Technology, Department of Biochemical and Microbial Technology, Ghent University, Ghent, Belgium.
KERMIT, Department of Data Analysis and Mathematical Modeling, Ghent University, Ghent, Belgium.
Appl Environ Microbiol. 2019 Apr 4;85(8). doi: 10.1128/AEM.02814-18. Print 2019 Apr 15.
Isogenic bacterial populations are known to exhibit phenotypic heterogeneity at the single-cell level. Because of difficulties in assessing the phenotypic heterogeneity of a single taxon in a mixed community, the importance of this deeper level of organization remains relatively unknown for natural communities. In this study, we have used membrane-based microcosms that allow the probing of the phenotypic heterogeneity of a single taxon while interacting with a synthetic or natural community. Individual taxa were studied under axenic conditions, as members of a coculture with physical separation, and as a mixed culture. Phenotypic heterogeneity was assessed through both flow cytometry and Raman spectroscopy. Using this setup, we investigated the effect of microbial interactions on the individual phenotypic heterogeneities of two interacting drinking water isolates. Through flow cytometry we have demonstrated that interactions between these bacteria lead to a reduction of their individual phenotypic diversities and that this adjustment is conditional on the bacterial taxon. Single-cell Raman spectroscopy confirmed a taxon-dependent phenotypic shift due to the interaction. In conclusion, our data suggest that bacterial interactions may be a general driver of phenotypic heterogeneity in mixed microbial populations. Laboratory studies have shown the impact of phenotypic heterogeneity on the survival and functionality of isogenic populations. Because phenotypic heterogeneity plays an important role in pathogenicity and virulence, antibiotic resistance, biotechnological applications, and ecosystem properties, it is crucial to understand its influencing factors. An unanswered question is whether bacteria in mixed communities influence the phenotypic heterogeneity of their community partners. We found that coculturing bacteria leads to a reduction in their individual phenotypic heterogeneities, which led us to the hypothesis that the individual phenotypic diversity of a taxon is dependent on the community composition.
同基因细菌种群在单细胞水平上表现出表型异质性是已知的。由于在混合群落中评估单个分类群的表型异质性存在困难，因此这种更深层次的组织对于自然群落的重要性仍然相对未知。在这项研究中，我们使用基于膜的微宇宙，允许在与合成或自然群落相互作用的同时探测单个分类群的表型异质性。在无菌条件下、作为物理分离的共培养物的成员以及作为混合培养物来研究各个分类群。通过流式细胞术和拉曼光谱法评估表型异质性。使用这种设置，我们研究了微生物相互作用对两种相互作用的饮用水分离物的个体表型异质性的影响。通过流式细胞术，我们证明了这些细菌之间的相互作用导致它们个体表型多样性的降低，并且这种调整取决于细菌分类群。单细胞拉曼光谱证实了由于相互作用而导致的分类群依赖性表型转变。总之，我们的数据表明，细菌相互作用可能是混合微生物种群表型异质性的一般驱动因素。实验室研究表明，表型异质性对同基因群体的生存和功能有影响。由于表型异质性在致病性和毒力、抗生素耐药性、生物技术应用和生态系统特性中起着重要作用，因此了解其影响因素至关重要。一个未解决的问题是混合群落中的细菌是否会影响其群落伙伴的表型异质性。我们发现共培养细菌会降低其个体表型异质性，这使我们假设一个分类群的个体表型多样性取决于群落组成。
