E. Coli Phage LZZ-17 Biochemical Characteristics And Genome-wide Research

【Objective】Phage by humans first discovered in 1915, is designed to bacteria for the host of the virus, made up of protein shell packages of genetic material. is well known and γ bacteriophage T4 bacteriophage. After entering the era of antibiotics, antibiotic resistant bacteria produced high, humans and the environment has caused serious harm, which prompted the search for new antibiotics and phage its high degree of specificity,stability, re-enter people’s attention. And there are many advantages of phage, phage into the host bacterial cell,you can rely on complete self-replicating host strain, so a small dose can achieve the desired results. Bacterial infections, especially in the treatment of multi-resistant bacteria, the phage has a more tremendous than antibiotics advantage. In the study of inactivated vaccines, phage lyase more widely, but can be highly purified lyase, and has a high substrate specificity, cleaving enzyme does not require infection and replication, so the sterilization rate, bacteria it is not easy to produce resistance.【Method】We collected fecal samples from poultry farms, YHE-9, BBZ2-2f, BBZ6-3f and HW5-3f as host bacteria, isolated from the feces of the corresponding phage, and phage purification proliferation. Conventional in vitro lysis assay dilution, Found an E. coli YHE-9 isolated phage LZZ-17 cleavage of the strongest, The phage temperature stability, optimum growth temperature optimum PH value measurement, determination of the optimal MOI, step growth curve determination, cracking spectroscopy. research the biochemical properties of indicators proved that the phage has a potential value as biological agents. Illumina Hise by the phage genome sequencing to obtain its information, the genomics research: Splicing sequences, evaluate the results of the assembly, the genomic structure of the basic features, ORF function prediction, genome annotation,phylogenetic analysis of phage LZZ-17, the phage LZZ-17 Bioinformatics Analysis lyase.【Result】Newly isolated phages LZZ-17 was purified by double plate assay indicated that the plaque clear and bright, neat edges, Diameter 2mm ~ 3mm(cultured 12h), The initial titer was 5.3 × 107 PFU / m L, Best MOI 0.1, Temperature in the range of 37 ℃ ~ 45 ℃, PH = 7 under conditions phage showed good stability.Step growth curve proof, The phage incubation period of 20 min, the amount of cleavage of 60.5. Stitching sequence genome of 37418 bp, after comments to give 71 open reading frame, We found no t RNA, It does not contain any resistance genes and virulence genes. Scan Gene mutations found in six sites: gp5, gp6, gp40,gp63, and two unknown mutations.【Conclusion】in conclusion Successfully isolated YHE-9 E. coli phage LZZ-17, has a strong cracking ability, sterilization effect is obvious, and the performance of each biochemical indicators show that the phage can be used as biological agent applications. Research on genomics discovery composition and structure of genes, the majority of essential genes are highly conserved, but there are also some point mutations, these mutations is not clear what impact would phage.