一株耐受蛋清蛋白的鸡蛋腐败菌S菌株的分离鉴定及其De novo测序分析

Identification of a Spoilage Bacterium S from Eggs with Tolerance to Egg White Protein and De novo Sequencing Analysis of the Strain

摘要:

本实验采用传统微生物培养法从鸡蛋中分离出一株革兰氏阳性腐败菌S菌株，经形态学观察、生理生化分析及16 S rDNA序列比对，对其进行了鉴定，并构建系统发育树。采用抑菌圈法及存活率试验探究该菌株对蛋清环境的耐受性，并基于Illumina HiSeq测序平台对该菌株的全基因组进行了De novo测序，获得基因组框架图。结果表明，该菌株生理生化反应特征与皮生球菌属相似，且16S rDNA序列与Dermacoccus abyssi（登录号AY894323）的同源性高达99%，鉴定为深渊皮生球菌（Dermacoccus abyssi）。该菌株在含有蛋清或溶菌酶的试管中能生长，在添加了蛋清或溶菌酶的孔径中没有抑菌圈产生。对蛋白编码基因的功能注释结果显示，细菌参与膜转运、离子结合、氨基酸和碳水化合物代谢及能量转换相关的基因丰富，推测其在鸡蛋中可能通过调节相关基因来耐受蛋清抑菌环境。该菌株对蛋清及溶菌酶的耐受性，为其在鸡蛋中的存活提供了有利条件。

Abstract:

A Gram-positive bacterial strain named S was isolated from egg by traditional microbial culture method. The strain was identified by morphological observation, biochemical analysis and 16S rDNA. The phylogenetic tree was also constructed. The tolerance of the strain to egg white environment was investigated by inhibition zone and survival test. The whole genome of the strain was sequenced using De novo system and a draft map was obtained. The results showed that the physiological and biochemical characteristics of the strain were similar to Dermacoccus genus, and the homology of 16S rDNA sequence with Dermacoccus abyssi (Accession number AY894323) reached 99%. The strain S was identified as Dermacoccus abyssi. The strain can grow in the test tube containing egg white or lysozyme. There was no bacteriostatic zone showed in the pore with egg white or lysozyme. Functional annotations of protein-coding genes showed that there were abundant genes involved in membrane transport, ion binding, amino acid and carbohydrate metabolism and energy conversion. It was speculated that these function clusters might be implicated in the strain to survival in the antimicrobial environment of egg white. The tolerance of the strain to egg white and lysozyme provided favorable conditions for its survival in eggs.