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Temperature affects cell growth, intracellular fatty acid species composition and content of one of the important factors. The change of unsaturated fatty acids in the membrane lipid ratio is one of the important mechanisms of biological tolerance to low temperature stress. Organisms under low temperature stress, usually enhance the unsaturated fatty acid content of the types of biofilm cells or increase the proportion of branched chain fatty acids, to enhance the fluidity of the membrane, so as to ensure the transport of the substance of the film, energy conversion, information Metabolism regulation and other normal physiological processes. More than reported in the literature, a variety of biological desaturase (polyunsaturated fatty acids in the classical pathway of the synthesis of an important class of enzymes) are significant temperature-sensitive factor. Schizosaccharomyces chytrid fungus Schizochytrium is a low class of marine fungi culture is simple, fast growth, fatty acid composition is simple and easy to purify, fermentation production of docosahexaenoic acid (Docosahexaenoic Acid, DHA) ideal strains . By shake flask fermentation, acid thermal method to extract oil by GC-MS analysis of the incubation temperature was found to affect the schizont chytrid fungus biomass, fat content and fatty acid composition of important environmental factors. Schizochytrium.sp FJU-512 could grow between 15 ℃ -37 ℃. At 15 ℃, while DHA content of more than 60%, but the biomass and fats yield far and the other temperature. 20 ℃ -30 ℃ bacteria grow better, higher fat content and DHA content is relatively stable. When the temperature rose to 37 ° C, biomass, fat content, and DHA content decreased. The total amount of saturated fatty acids the highest content of 37 ℃, 15 ℃ minimum, to maintain a constant 20 ℃ -30 ℃; unsaturated fatty acids, total in the 15 ° C the highest content, 37 ℃ minimum, to maintain a constant 20 ℃ -30 ℃. Applied for the first time the differential proteomics temperature the molecular mechanism Schizochytrium control, help understanding of Schizochytrium fat metabolism. Through exploring suitable sample preparation method and two-dimensional electrophoresis conditions, the successful establishment of a system of two-dimensional electrophoresis for separation in fission the chytrid fungus soluble protein. Final schizont-the chytrid fungus soluble protein extraction method established glass bead breakers combined with TCA / acetone precipitation the demineralization processing method for two-dimensional electrophoresis, IPG strips pH 3-10 (24cm) to meet the needs of two-dimensional electrophoresis analysis , at the same time lay the foundation for the mass spectrometric identification. Three growth temperature selected the DHA yield significant differences, namely low temperature stress (15 ℃), the optimum temperature (28 ℃) and high temperature stress (37 ℃), comparative analysis of proteome map of Schizosaccharomyces chytrid fungus stimulation at different temperatures; The point of difference is selected for MS analysis identified 8 temperature-sensitive factor. The effects of temperature on bacteria is very wide, these changes significantly protein related to glycolysis, kinase activity, the transfer of electronic chain amino acid metabolism, active oxygen free radicals, oxidative phosphorylation, nucleic acid and protein synthesis, energy metabolism and other relevant . Most of the proteins involved in energy metabolism, glycolysis, the primary metabolism create a new dynamic balance the schizont chytrid fungus temperature stress to adapt to the low temperature. Real-time PCR technology detects temperature stress schizont chytrid fungus superoxide dismutase, heat shock protein, cytochrome b5 three temperature-sensitive gene expression level differences, from the point of view of the mRNA levels of proteomic mass spectrometry results verify the correctness sex. In addition, from the perspective of bioinformatics analysis schizont the chytrid fungus superoxide dismutase protein sequence. Explore the impact of temperature-sensitive factor of the bacteria energy conversion, material transport, metabolism, and other physiological processes information, explore with DHA and other highly unsaturated fatty acid biosynthesis associated adaptation mechanisms to reveal fission chytrid fungus temperature at the molecular level.
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