RAPD Typing Of Enterococcus Isolated Form Silkworm And Separation And Purification Of Substance That Like Enterococins

Enterococcus was the natural flora comes from enteron of silkworm. Which concerned with multiform physiological metabolism and was the important ingredients of host's physiological activities.Enterococcus was a potential pathogen . The healthy silkworm had enough precautionary ability, It played pathogenic part only when the host become weak or they were in bad condition , and it arosed the intestinal tract disease of silkworm. So making a study of enterococcal biological characteristics and the ecological change was important to find out the peccant mechanism of bacterial intestinal tract disease and the interaction between Enterococcus and other pathogenic bacterium.The traditional critical method of numerical taxonomy demands a great deal of work and much time. RAPD was one of the important means in molecular biology. It could reflect the difference between specimen in DNA level. We founded and optimized the reaction system and condition of enterococcus by adjusting concentration of Mg2+, quality of DNA template, concentration of primer,quality of TaqDNA polymerase, PCR cycle index. On this basic, we studied DNA polymorphism of 14 enterococcal strains and 3 reeferance cultures, isolated from the intestines of silkworm and having variety of physiological biochemical characteristic.Then we ascertained RAPD reaction system and process. The total volume of mplified reaction was 25μL, it included DNA template 50 ng; Mg2+ 3.5 mmol/L; dNTPs 200 mmol/L; Taq DNApolymerase 3U; concentration of primer 15pmol/L; PCR amplified process: preliminary denaturalization 94℃for 3 min,denaturalization 94℃for 40 s;annealing 35℃for 40 s,extend 72℃for 1 min,cycle for 45, extending the last circulation 72℃for 10 min,then conserved in 4℃. We got 625 site by using 8 stochastic primers. Thereinto, 99.7 % waspolymorphous site. It indicated the DNA polymorphism of the strains were abundant。To cluster analysis the results of amplification,the testing strains were divided into 4 sorts: Ent.faecium,Ent.casseliflavus,Ent.avium,Ent.faecalis. The result of RAPD typing had the accordant result as the numerical appraise basically.The former studies indicated that the exocrine protein of enterococcus origined...