PR000632 (Project)

Description:Low temperature is the most wide-spread “hostile” environmental factor on earth while at the same time the most common condition for marine organisms. However, the unique adaptive mechanisms that enable the survival of marine microorganisms under low temperature are unclear. Since low temperature is always accompanied by high pressure and other adverse conditions in marine environment, here we studied the metabolic adaptation of a marine strain to prolonged low temperature under high pressure. The strain studied is a psychrotolerant Microbacterium sediminis isolated from deep sea sediment. By using 1H nuclear magnetic resonance (NMR)-based metabolomics approach, we detected the spectral data of polar extracts of the strain M. sediminis, and applied multivariate statistical analysis methods together with univariate analysis to analyze metabolic profiles associated to different conditions. The metabolic profiles of the M. sediminis strain cultivated under high pressure at low temperature were distinctly different from those cultivated under high pressure at normal temperature. We identified the differential metabolites which were responsible for distinguishing the metabolic profiles and compared their relative intensities between groups. We also compared the different adaptive responses of the strain at different growth stages to the prolonged low temperature under high pressure. We proposed that the low-temperature adapting process of the M. sediminis strain involves, 1) the regulation of osmotic pressure using amino acids as possible alternative osmolytes, and, 2) the strengthen of glycolysis and the maintenance of TCA cycle via amino acids anaplerotic reaction. We put forward that the main difference of adaptation to low temperature for the strain at different growth stages was related to energy metabolism. Our findings improved the understanding of the low-temperature adaptive mechanisms for marine microorganisms under high pressure on the metabolic level.