The Screening Study Of Prokaryotic Expression Host Strain

Screening 500 strains from the seawater and mud,test the antibacterial activity the activity of proteinase.Screening for prokaryotic expression host strains,establishment and optimization of Bacillus subtilis HS-A38 recombinant plasmid transformation method.The endospore-forming rhizobacterium Bacillus subtilis the model organism forgram positive organisms is strongly against adverse environment and both bacterial and fungal pathogens.It is proved to be able to produce more than two dozen of antibiotics with amazing varieties of stru ctures.A lot of natural isolates with excellent propeties of Bacillus subtills have been screened and applied widely.This experiment chooses 8.5 KB large plasmid electricity transformation,provide a reference for the larger molecular weight high electric conversion of recombinant plasmid and the high electricity conversion use the wild type bacillus as the host.Provide the reference for other wild-type bacteria,and to establish a suitable for industrial applications of the secretion of prokaryotic expression host.The Bacillus subtilis HS-A38 as host strains,the electricity conversion into recombinant plasmid pHT43-SjLys,study different voltage plate coated the product concentration and plasmid transformation and the characteristic of common training time to confront a grain of conversion effciency.The antibacterial activity of strains was tested using the indicator Staphylococcu saureus?Micrococcus lysodeikticus?Pseudomonas aeruginosaand Vibrio parachaemolyticus.Bacteriostatic activity of high and low protease activity of strains as the host strain.The recombinant plasmid insert the sea cucumber lysozyme gene,in recent years,researches of lysozyme from many sources have been done widely.This experiment through screening does not produce protease strains,in order to obtain better effect of exogenous protein expression.The most suitable host strain as prokaryotic expression strains is Bacillus subtilis HS-A38.The optimized method is suitable for Bacillus subtilis HS-A38 conversion,conversion rate is up to 3633 CFU/?g DNA.By PCR screen with transformed plants,the positive rate is 89.3%.The optimal conditions of Bacillus subtilis HS-A38 strains are electric voltage of 2 KV,coated plate when the product transformation content of 16.7%,plasmid with cells culture time of 1.5 h.