Effects Of Environmental Factors On Exopolysaccharide Synthesis And Related Gene Expression Regulation In Pseudoalteromonas Issachenkonii HZ

Marine environment contains rich biological resources,marine microorganisms due to the specificity of their living environment led to the polysaccharide structure of the specificity and function of the specificity,and there are a lot of literature that the production of extracellular polysaccharides contribute to harsh environments The survival of the bacteria,temperature,pH and other environmental factors will also affect the structure and composition of extracellular polysaccharides over the years,due to the complexity of the marine environment makes the scientists gradually from the tidal field of microbial microbial organisms,a lot of time report on the production of active substances in marine microbes,but scientists have little research on the mechanism by which the extracellular polysaccharides produced by marine microbes are regulated by environmental factors.In this paper,a strain of bacteria isolated from the plate was prepared by phenol sulfuric acid method.It was able to produce a large number of extracellular polysaccharides.The molecular biology identification and morphological characteristics were named as Pseudoalteromonas issachenkonii HZ.In this paper,the structure of extracellular polysaccharide produced by marine bacteria under two different environmental factors was analyzed and the guidance of one of the key enzymes in the synthesis pathway of Pesudoalteromonas issachenkonii HZ extracellular polysaccharide Glycosyltransferase gene was amplified and the expression of glycosyltransferase gene was regulated by temperature,pH and sea salt concentration by means of real-time fluorescence quantitative PCR.The results were as follows:The effects of different environmental factors on the structure of extracellular polysaccharide of Pesudoalteromonas issachenkonii HZ were studied.The effects of different environmental factors on the structure of extracellular polysaccharide of Pesudoalteromonas issachenkonii HZ were studied.The effects of different environmental factors on the structure of extracellular polysaccharide of Pesudoalteromonas issachenkonii HZ were studied by the method of water extraction and remove protein by Sevage,used DEAE-52 and Sephadex-G100 to puried the polysaccharide.The structures of extracellular polysaccharides were analyzed by Fourier transform infrared spectroscopy?FTIR?,nuclear magnetic resonance?NMR?and gas chromatography mass spectrometry?GS-MS?.Analysis of gas chromatography mass spectrometry showed that there were no differences in the monosaccharide composition of extracellular polysaccharides under two different environmental conditions,but the composition ratio was different.According to the Fourier transform infrared spectroscopy,15?had a different absorption peak at 1382.9 cm^-1.In combination with the literature and the four chapter,it was suggested that the bacteria could adapt to the external environment through the polysaccharide secretion and polysaccharide Changes,and thus protect the bacteria to survive.The polymorphism of the exopolysaccharide was determined by nuclear magnetic resonance spectroscopy,15?Extracellular polysaccharide has an absorption peak at?159.764 ppm,indicating that it may contain uronic acid.An extracellular polysaccharide at 25?showed an absorption peak at?20 ppm,indicating that it contained methyl sugar.The primers were successfully obtained from Pesudoalteromonas issachenkonii HZ by PCR.The fragment was 1390bp,which was translated into a protein sequence and then aligned in NCBI.It was linked to the known glycosylation of the same strain.Enzyme sequences are similar and have high homology.Therefore,we speculate that the amplified 1390 bp fragment is a directed glycosyltransferase gene sequence.At the same time,the effects of temperature,pH and sea salt concentration on the expression of glycosyltransferase were detected by real-time fluorescence.The analysis of the data showed that the glycosyltransferase gene was more easily expressed at low temperature,The expression level of glycosyltransferase was increased at 20 h,and the expression of glycosyltransferase was increased at 15h and 35?.The expression of glycosyltransferase at 15?and 35?was 5.2 times And the expression level of glycosyltransferase was 2.5 times when the salt concentration was 4.5%,and the expression level of glycosyltransferase was 2.0 times of that of sea salt.The expression levels of glycosyltransferase in the medium at pH 8 and 9 were 1.64 and 1.67 times of that of pH 7 respectively at 10h.The results provide a basis for exploring the adaptability mechanism of cell environment.