State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources, Fujian Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, 184 Daxue Road, Xiamen, 361005, China.
College of Chemistry and Chemical Engineering, Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Xiamen University, Xiamen, 361005, China.
Appl Microbiol Biotechnol. 2020 Jan;104(1):277-289. doi: 10.1007/s00253-019-10134-4. Epub 2019 Nov 14.
The most wide-spread "hostile" environmental factor for marine microorganisms is low temperature, which is usually accompanied by high hydrostatic pressure (HHP). Metabolic mechanisms of marine microorganisms adapting to prolonged low temperature under HHP remain to be clarified. To reveal the underlying metabolic mechanisms, we performed NMR-based metabolomic analysis of aqueous extracts derived from a psychrotolerant Microbacterium sediminis YLB-01, which was isolated from deep-sea sediment and possess great biotechnology potentials. The YLB-01 cells were firstly cultivated at the optimal condition (28 °C, 0.1 MPa) for either 18 h (logarithmic phase) or 24 h (stationary phase), then continually cultivated at either 28 °C or 4 °C under HHP (30 MPa) for 7 days. The cells cultivated at low temperature, which experienced cold stress, were distinctly distinguished from those at normal temperature. Cold stress primarily induced metabolic changes in amino acid metabolism and carbohydrate metabolism. Furthermore, the logarithmic and stationary phase cells cultivated at low temperature exhibited distinct metabolic discrimination, which was mostly reflected in the significantly disturbed carbohydrate metabolism. The logarithmic phase cells displayed suppressed TCA cycle, while the stationary phase cells showed decreased pyruvate and increased lactate. In addition, we performed transcriptome analysis for the stationary phase cells to support the metabolomic analysis. Our results suggest that the cold adaptation of the psychrotroph YLB-01 is closely associated with profoundly altered amino acid metabolism and carbohydrate metabolism. Our work provides a mechanistic understanding of the metabolic adaptation of marine psychrotrophs to prolonged low temperature under HHP.
海洋微生物最广泛的“敌对”环境因素是低温，通常伴随着高静压（HHP）。海洋微生物在 HHP 下适应长期低温的代谢机制仍有待阐明。为了揭示潜在的代谢机制，我们对从深海沉积物中分离出的耐冷微生物 Microbacterium sediminis YLB-01 的水提物进行了基于 NMR 的代谢组学分析，该微生物具有巨大的生物技术潜力。YLB-01 细胞最初在最佳条件（28°C，0.1 MPa）下培养 18 小时（对数期）或 24 小时（静止期），然后在 28°C 或 4°C 下在 HHP（30 MPa）下连续培养 7 天。在低温下培养的细胞经历冷应激，与在正常温度下培养的细胞明显不同。冷应激主要诱导氨基酸代谢和碳水化合物代谢的代谢变化。此外，在低温下培养的对数期和静止期细胞表现出明显的代谢差异，主要反映在碳水化合物代谢的明显紊乱上。对数期细胞表现出 TCA 循环受到抑制，而静止期细胞表现出丙酮酸减少和乳酸增加。此外，我们对静止期细胞进行了转录组分析，以支持代谢组学分析。我们的结果表明，嗜冷菌 YLB-01 的冷适应与氨基酸代谢和碳水化合物代谢的显著改变密切相关。我们的工作为海洋嗜冷菌在 HHP 下长期低温适应的代谢适应提供了机制上的理解。
