School of Health and Life Sciences, University of Health and Rehabilitation Sciences, Qingdao, China.
College of Marine Life Sciences, Ocean University of China, Qingdao, China.
Appl Environ Microbiol. 2023 Oct 31;89(10):e0060123. doi: 10.1128/aem.00601-23. Epub 2023 Sep 28.
Ocean warming profoundly impacts microbes in marine environments; yet, how lifestyle (e.g., free living versus biofilm associated) affects the bacterial response to rising temperature is not clear. Here, we compared transcriptional, enzymatic, and physiological responses of free-living and biofilm-associated M597, a member of the family isolated from marine biofilms, to the increase in temperature from 25℃ to 31℃. Complete genome sequencing and metagenomics revealed the prevalence of M597 in global ocean biofilms. Transcriptomics suggested a significant effect on the expression of genes related to carbohydrate metabolism, nitrogen and sulfur metabolism, and phosphorus utilization of free-living M597 cells due to temperature increase, but such drastic alterations were not observed in its biofilms. In the free-living state, the transcription of the key enzyme participating in the Embden-Meyerhof-Parnas pathway was significantly increased due to the increase in temperature, accompanied by a substantial decrease in the Entner-Doudoroff pathway, but transcripts of these glycolytic enzymes in biofilm-forming strains were independent of the temperature variation. The correlation between the growth condition and the shift in glycolytic pathways under temperature change was confirmed by enzymatic activity assays. Furthermore, the rising temperature affected the growth rate and the production of intracellular reactive oxygen species when M597 cells were free living rather than in biofilms. Thus, biofilm formation stabilizes metabolism in M597 when grown under high temperature and this homeostasis is probably related to the glycolytic pathways.IMPORTANCEBiofilm formation is one of the most successful strategies employed by microbes against environmental fluctuations. In this study, using a marine Roseobacteraceae bacterium, we studied how biofilm formation affects the response of marine bacteria to the increase in temperature. This study enhances our understanding of the function of bacterial biofilms and the microbe-environment interactions in the framework of global climate change.
海洋变暖对海洋环境中的微生物产生深远影响；然而，生活方式（例如自由生活与生物膜相关）如何影响细菌对温度升高的反应尚不清楚。在这里，我们比较了从海洋生物膜中分离出的 家族成员 M597 的自由生活和生物膜相关形式对温度从 25℃升高到 31℃的转录、酶和生理响应。全基因组测序和宏基因组学揭示了 M597 在全球海洋生物膜中的普遍性。转录组学表明，由于温度升高，自由生活 M597 细胞中与碳水化合物代谢、氮和硫代谢以及磷利用相关的基因表达受到显著影响，但在其生物膜中未观察到这种剧烈变化。在自由生活状态下，由于温度升高，参与 Embden-Meyerhof-Parnas 途径的关键酶的转录显著增加，同时 Entner-Doudoroff 途径大量减少，但生物膜形成菌株中这些糖酵解酶的转录不受温度变化的影响。通过酶活性测定证实了生长条件与温度变化下糖酵解途径变化之间的相关性。此外，当 M597 细胞自由生活而不是在生物膜中时，升高的温度会影响其生长速度和细胞内活性氧的产生。因此，在高温下生长时，生物膜形成稳定了 M597 的代谢，这种内稳性可能与糖酵解途径有关。
重要性
生物膜形成是微生物应对环境波动的最成功策略之一。在这项研究中，我们使用一种海洋玫瑰杆菌科细菌研究了生物膜形成如何影响海洋细菌对温度升高的反应。这项研究增强了我们对细菌生物膜功能和微生物-环境相互作用的理解，这是在全球气候变化的框架内进行的。
