Chemotaxis, growth, and interspecies interactions using the in situ chemotaxis assay

We address how bacterial chemotaxis toward phytoplankton metabolites and their subsequent catabolism influences assembly in simple two-species model communities using the in situ chemotaxis assay (ISCA). To this end, we measured the individual chemotactic strengths and growth rates of seven bacterial strains (previously isolated from coastal seawater enriched with phytoplankton exometabolites in response to representative phytoplankton metabolites: dimethylsulfoniopropionate (DMSP) spermidine, 2,3-dihydroxypropane-1-sulfonate (DHPS), trimethylamine (TMA), xylose, ectoine, glutamate, glycolate, isethionate, ribose. We then mimicked the early phase of bacterial community establishment in metabolite hotspots by conducting experiments with pairs of bacterial species and monitoring subsequent community composition following chemotaxis and growth on these metabolites,

本研究利用原位趋化性测定法（in situ chemotaxis assay, ISCA），探讨细菌对浮游植物代谢物的趋化作用及其后续分解代谢，如何影响简单双物种模型群落的组装过程。为此，我们测定了7株细菌菌株的个体趋化强度与生长速率；这些菌株此前从富集浮游植物外代谢物的沿岸海水中分离得到，该分离工作针对下述代表性浮游植物代谢物展开：二甲基巯基丙酸内盐（dimethylsulfoniopropionate, DMSP）、亚精胺（spermidine）、2,3-二羟基丙烷-1-磺酸盐（2,3-dihydroxypropane-1-sulfonate, DHPS）、三甲胺（trimethylamine, TMA）、木糖（xylose）、四氢嘧啶（ectoine）、谷氨酸盐（glutamate）、乙醇酸（glycolate）、羟乙基磺酸盐（isethionate）以及核糖（ribose）。随后，我们通过双菌株共培养实验，监测细菌在这些代谢物上发生趋化作用并增殖后的群落组成变化，以此模拟代谢物热点区域中细菌群落构建的早期阶段。