Preparation Of Tea Plant GAD Gene Engineering Lactococcus And Study On Ability To Tolerate Stress

As a probiotics,lactic acid bacteria widely exists in human and animal intestines,and it were widely exploited and utilized by people because of its have multiple health care functions.However,in the process of its growth,it will be inhibited by its own and external environment of various kinds of stress in the process of its growth.As a non-protein amino acid GABA is widely exist in living organisms,which involved in a variety of biological process of growth and protection against environmental stress,Therefore,and it can also help lactic acid bacteria to improved the ability of tolerate stress.All in all,study of the role which GABA played in the process of lactobacillus lactic proliferation has the vital significance.In this study,we use two ways to observe the growth situation of lactate lactobacillus under in acidic condition and the low temperature condition,one is adding a certain concentration of exogenous GABA,the other is expression CsGAD to product GABA.In order to provide the possible ways to improve the growth statement of lactic acid bacteria and obtained the lactic acid bacteria which have high yield of GABA.The main results are: 1.The analysis on the influence of the growth condition of lactobacillus lactic acid under the acid condition when exogenous added GABA.This study observed the changes of lactic acid the growth condition of lactobacillus measured by growth curve.The biggest biomass which under the normal circumstances have no obvious changes in lactic acid bacteria,but in the acidic conditions when added GABA has a slight growth of lactic acid bacteria.2.The analysis on the influence of the growth condition of lactobacillus lactic acid under the low temperature when exogenous added GABA.This study use the lactic acid bacteria which cultivated to the mid logarithmic phase,the early stage of the plateau and the plateau when exogenous added GABA in its medium,and then put them in 4 ? and 20 ?,observed the growing number of changes.We found that:The growth of lactobacillus lactic acid in three different period and the growth condition is different,too.But with the extension of time in low temperature,the lactobacillus lactis which added GABA in its medium have a obvious advantage to the lactobacillus lactis which added nothing in its medium in survivor.3 The analysis of growth status about lactococcus lactis which containing CsGAD gene.This study used genetic engineering means to a CsGAD genes into lactococcus lactis NZ9000,then observed the changes of growth curve under the acidic conditions about the genetically engineered bacterium after nisin induced,and the number of survival under the low temperature treatment between the three different growth periods.And the research found that when added revulsant nisin solution in the medium,the biggest biomass of recombinant bacteria will be increased.Under the condition of low temperature to a certain period of time,the survivor of recombinant bacteria significantly more than the other one during the three period.