Isolation and identification of phage SWH-Ab-1 against Acinetobacter baumannii and bioinformatic analysis of its major functional genes
LUO Juan;ZHANG Ran;WU Liu;LUO Xi;ZHANG Bo;Department of Hospital Infection Management,Southwest Hospital,Army Medical University;Nanchang University Queen Mary School;
Objective To isolate the Acinetobacter baumannii(A. baumannii) phages,sequence the genome and predict the properties and functions of the major functional genes such as holin and lyase.Methods An A. baumannii phage was isolated from raw sewage of a hospital and identified using doublelayer-agar method. The morphology of the phage was observed by electron microscopy. The genomic DNA of the phage was extracted and sequenced using Illumina Hiseq2000 technique. Bioinformatic analysis was used to analyze the nucleotide sequence of the phages,including functional genes location and homology analysis,and to predict the structures and biological functions of the major encoding proteins. Results An A. baumannii phage was successfully isolated and named as SWH-Ab-1. Bacteriophage SWH-Ab-1 belonged to the Siphoviridae,which had significant lytic activity against A. baumannii. The genome of bacteriophage SWHAb-1 was a double-strand DNA with a full length of 41 567 bp,in which the G + C mol% was 39. 4% and 51 predicted genes were involved. The holin gene and the lysin gene were located in the ORF02(320 ~ 655 bp)and the ORF03(642 ~ 1 199 bp) of SWH-Ab-1, respectively. Hol SA1, consisting of 111 amino acids(336 bp),was a hydrophobic Ⅰ transmembrane protein,at a molecular mass of 11. 957 96 × 103,with a theoretical isoelectric point of 4. 87,which might play an important role in fatty acid metabolism,transport and signal transduction. Lys SA1 consisted of 185 amino acids(558 bp),was a hydrophilic protein without transmembrane regions,its molecular mass was 21. 010 4 × 103,and its theoretical isoelectric point was 9. 56,which might function in amino acid biosynthesis,fatty acid metabolism and biosynthesis of cofactors. The secondary structure of the 2 proteins was mainly composed of alpha helixes and random coil,and both of them were lack of signal peptide. Conclusion Bacteriophage SWH-Ab-1 is a new lytic phage,belonging to the Siphoviridae family. The open reading frames ORF02 and ORF03 are the encoding genes of phage SWH-Ab-1 genome. Hol SA1 and Lys SA1 might form a "two-element lysis system"together in order to lyse the host bacteria.
【Fund】： 第三军医大学第一附属医院临床科研专项(SWH2014LC31);; 重庆市社会民生科技创新专项(cstc2015shmszx120110);; 中国工程物理研究院科学技术发展基金(物理与生物医学交叉方向)(WSS-2015-01)~~
【CateGory Index】： R446.5
【CateGory Index】： R446.5