Molekulare Mikrobiologie, Institut für Allgemeine Mikrobiologie, Kiel University, Kiel, Germany.
Marine Evolutionary Ecology, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany.
Microbiologyopen. 2020 Sep;9(9):e1094. doi: 10.1002/mbo3.1094. Epub 2020 Jul 11.
The associated microbiota of marine invertebrates plays an important role to the host in relation to fitness, health, and homeostasis. Cooperative and competitive interactions between bacteria, due to release of, for example, antibacterial substances and quorum sensing (QS)/quorum quenching (QQ) molecules, ultimately affect the establishment and dynamics of the associated microbial community. Aiming to address interspecies competition of cultivable microbes associated with emerging model species of the basal animal phyla Cnidaria (Aurelia aurita) and Ctenophora (Mnemiopsis leidyi), we performed a classical isolation approach. Overall, 84 bacteria were isolated from A. aurita medusae and polyps, 64 bacteria from M. leidyi, and 83 bacteria from ambient seawater, followed by taxonomically classification by 16S rRNA gene analysis. The results show that A. aurita and M. leidyi harbor a cultivable core microbiome consisting of typical marine ubiquitous bacteria also found in the ambient seawater. However, several bacteria were restricted to one host suggesting host-specific microbial community patterns. Interbacterial interactions were assessed by (a) a growth inhibition assay and (b) QS interference screening assay. Out of 231 isolates, 4 bacterial isolates inhibited growth of 17 isolates on agar plates. Moreover, 121 of the 231 isolates showed QS-interfering activities. They interfered with the acyl-homoserine lactone (AHL)-based communication, of which 21 showed simultaneous interference with autoinducer 2. Overall, this study provides insights into the cultivable part of the microbiota associated with two environmentally important marine non-model organisms and into interbacterial interactions, which are most likely considerably involved in shaping a healthy and resilient microbiota.
海洋无脊椎动物的相关微生物群落对宿主的适应性、健康和体内平衡起着重要作用。由于抗菌物质和群体感应（QS）/群体淬灭（QQ）分子的释放，细菌之间存在着合作和竞争相互作用，最终影响相关微生物群落的建立和动态。为了解决与新兴基础动物门刺胞动物门（Aurelia aurita）和栉水母门（Mnemiopsis leidyi）的模式生物相关的可培养微生物之间的种间竞争，我们采用了经典的分离方法。总体而言，从 A. aurita 水螅和息肉中分离出 84 株细菌，从 M. leidyi 中分离出 64 株细菌，从环境海水中分离出 83 株细菌，然后通过 16S rRNA 基因分析进行分类学分类。结果表明，A. aurita 和 M. leidyi 拥有可培养的核心微生物组，其中包括在环境海水中也发现的典型海洋普遍存在的细菌。然而，有几种细菌只局限于一种宿主，表明宿主具有特定的微生物群落模式。通过（a）生长抑制试验和（b）QS 干扰筛选试验评估了细菌间的相互作用。在 231 株分离物中，有 4 株细菌分离物在琼脂平板上抑制了 17 株分离物的生长。此外，231 株分离物中有 121 株显示出 QS 干扰活性。它们干扰了酰基高丝氨酸内酯（AHL）为基础的通讯，其中 21 株同时干扰了自体诱导物 2。总的来说，这项研究提供了对与两种具有重要环境意义的海洋非模式生物相关的微生物群的可培养部分以及细菌间相互作用的深入了解，这些相互作用很可能在塑造健康和有弹性的微生物群方面发挥了重要作用。
