| To optimize yeast probiotic which is from the meat duck digestive tract and explore its mechanism.7 strains saccharomyces cerevisiae form which separated from meat duck digestive trace in the lab are researched,we selected High Heat Resistance and tolerance to starvation,and then explored the correlation of heat shock protein expression from yeast cellula with ambient temperature,explored the correlation of dextran content with trehalose content in yeast cell wall under nutrient starvation.We firstly compared the heat resistance from different strains by heat stress preconditioning,then broke the yeast cell to release of intracellular protein,and analyzed the Heart Stress Protein expression features of different strains by using SDS-PAGE electrophoresis.Cultivate yeast cells under nutrient starvation to detection the dextran and trehalose yeast cell wall by using High Performance Liquid Chromatography.Analyzed the correlation of different strains of nutrition hungry tolerability with dextran and trehalose.The contents and results of this study are as follows:1:Compared to the other two method of breaking cell wall-Freeze thawing and ultrasonic,the effect of high pressure homogenization is the best.The best technological condition of high pressure homogenization method is that the homogenization pressure is 140 Mpa,and the circulation is 3 times,the bacteria liquid is diluted 102 times of the original one.Then the wall-broken rate is up to 94.5%.2:Preliminary study on the mechanism of beat tolerance of yeast under different temperature stress conditions,and the results show:(1):5 of the 7 strains of saccharomyces cerevisiae had a small amount of heat shock protein expression in heat shock protein 70 family and 90 family when they were in the normal state.(2):Target protein could not be seen clearly at 30?,it would be gradually clear above 37?,the expression of the ratio reached the maximum above 42? and secretion reached the highest value.Although there was still a target protein,but its expression was not enough and gradually reduced.(3):Compared with other strains,the tolerance of NO.7 yeast strains is better at 45? and 48?.and the expression level of its heat shock protein 70 and 90 were also higher.3:Preliminary study on the mechanism of tolerance to starvation tolerance of yeast probiotics,and the results show:(1):Most of the strains were resistant to the limitation nutritional starvation at 6th days.In addition,7th strains of yeast were better in nutritional starvation tolerance,and the number of viable bacteria was still higher than that of other strains in 12 th days.(2):During the experiment of nutrient starvation tolerance,7 strains of saccharomyces cerevisiae all experienced the process where the number of colonies increased after decreasing or reduced slowly.Based on the existing literature inference,it was supposed that the phenomenon may be due to the autophagy in yeast cells.(3):we get the content of dextran and trehalose from experiment we were doing about the starvation tolerance of brewer's yeast and its research mechanism,it was firstly concluded that the nutrient starvation tolerance of 4th strains was worse,and 7th strains' was better than that of that strains.Conclusion:heat resistance and nutrient starvation tolerance of yeast strains of duck digestive tract have differences.The heat resistance of different strains was closely related to the expression of heat shock protein 70 and 90 families.The tolerance of nutrient starvation was similar to the accumulating of dextran and trehalose.Heat stress tolerance and nutritional starvation tolerance of NO.7 strain of the expression were the best.And it can be used as alternative follow-up special duck feed probiotics preparation. |
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