Study On Isolation And Gene Immunization Of Mycoplasma Gallisepticum

Milk is sampled from Inner Mongolia region ranch, Separation and purification40Bacillus. Identification of the morphological characteristics of Bacillus colony and cell and its tolerability, growth temperature, salt tolerance and some other column physiological and biochemical tests are carried out. Then, through the screening9strains producing protease are selected. According to the results of screening and check again after high-temperature sterilization, choose3strains of the highest enzyme activity that is heat-resistant high thermophilic Bacillus HG7、HZ2、HZ4. Contrast the physiological and biochemical identification of these three bacteria, finally identificated by the identification of Molecular Biology16S rDNA that HG7、HZ2、HZ4are all Bacillus subtilizes. Then get the stable strains which have the properties of high temperature resistant. The D value and Z value are used to a common characterization for it, the temperature, pH, ultraviolet radiation, heat-moisture treatment and other external environment effect on heat tolerance are carried out, studying the concentration of NaCl, sugar, whey protein, and other food components on heat resistance of Bacillus.We found that the heat resistance decreased significantly with the increase of temperature by studying the influence of external conditions on the heat resistance. Bacillus subtilizes is most suitable for enzyme production around pH value of7, which belongs to the high temperature resistant, neutral protease. Under pH5.0and over10.0spores heat-resistant dropped significantly, when PH value is close to neutral, the damage to the cells of spore is the most minimum and the most sensitive to temperature. Ultraviolet radiation has only very weak inhibitory effect on heat resistance of bacterial spores, and the outside water effect on bacillus spores heat resistance is negligible.NaCl solution which the concentration from2%to6%makes Bacillus heat resistance increased significantly, indicating that NaCl concentration has a good protective effect on bacillus. When the concentration of sucrose increased from0to50%, there is no significant change of the heat resistance of the spore, indicating that the sugar concentration had no effect on D was Bacillus spores. When whey protein reached8%the heat resistance of spores increases obviously, but in121℃when the concentration is4%and8%whey protein had no significant change compared with blank. Sucrose under acid condition has protective effect on bud, but increasing the bud sensitivity to heat up; the presence of10%sucrose, low pH can increase sensitivity to temperature.