Screen Of New Antibiotic And Heterologous Expression Of Antimicrobial Peptide PSI

The abuse of antibiotic leads to the emergence of a large number of resistant strains,especially the emergence of super resistant strains,which poses a serious threat to human health.It is of great urgent need for protecting human health and plant resistance to development of more safe and effective antibiotics or substitutions that are not drug resistance.Seeking new antibiotics from the secondary metabolites of extreme environment microbial and finding new substances(antibacterial peptide)is the efficiently way to solve antibiotics that produce drug resistance.In this paper,the two anti-microbial directions researches of a new antibiotic is screen?purification?identify from the Streptomyces in extreme environment of Tibet Plateau and 3 kinds plant antimicrobial peptide PSI(Plant-specific insert)heterologous expression in Kluyvermyces lactis.The main results are as follows:1.25 strains of Streptomyces capable of effectively inhibiting MRSA(Methicillin-resistant Staphylococcus aureus)were screened from 115 soil samples of the Tibet Plateau,which strain5-1-3 has good antibacterial effect and its belongs to Streptomyces agglomeratus.2.Completed the genomic map of Streptomyces agglomeratus 5-1-3 and found the genome is 9.5M,encoded 8408 open reading frames(ORFs),which 5548 encoded proteins were clustered into the direct homologous protein(COG)and 3% are secondary metabolites.Through ANtiSMASH analysis,31 secondary synthetic gene clusters of synthetic antibiotics were found.3.The compounds were separated and identified from Streptomyces agglomeratus 5-1-3,which could inhibit MASA efficiently and the molecular weight of is 256.The compound was found to be a new type of antibiotic by structural comparison.4.The PSI gene from Prunus persica(PP),Vitis vinifera(VV)and Citrus sinensis(CS)was synthesized by the whole gene synthesis,joining p KLAC1 vectors and transform to Kluyeromyces lactis.The secretory antibacterial peptide PSI(named PSI-PP,PSI-VV and PSI-CS)was successfully induced and its induction conditions were optimized.The yield was enhanced by mutagenesis and fermentation and the purification was further obtained by the purification of PSI.5.Found that PSI-PP had bacteriostasis effect on AsperguLlus niger and Ananas comosus;PSI-VV had bacteriostasis against Verticillium dahliae and Colletotrichum truncatum;and PSI-CS had bacteriostasis on Penicillium simplicissimum?Botryosphaeria dothidea andColletotrichum truncatum,using 10 fungi to detect the antibacterial spectrum in 3 kinds of antibacterial peptides of PSI-PP,PSI-VV,PSI-CS.In summary,a strain of Streptomyces agglomeratus 5-1-3 with strong antiMRSA ability was isolated,a new type of antibiotic was extracted from it and heterologous expression of 3 kinds anti fungal antimicrobial peptide PSI in yeast in this paper.The results of this study will provide new ideas for the development of new non-drug resistant antibiotics or alternatives to antibiotics.