冷却猪肉中产蛋白酶腐败菌的分离鉴定
Isolation and identification of proteolytic spoilage bacteria in chilled pork
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摘要: 腐败菌的蛋白水解活性在冷却猪肉腐败过程中发挥重要作用,而蛋白酶的表达可能与群体感应(quorum sensing,QS)有关。用脱脂乳平板法从冷却猪肉中分离出54株产蛋白酶腐败菌,经根癌农杆菌(Agrobacterium tumefaciens)PELR4检测,有44株产生N-酰基高丝氨酸内酯(N-acyl homoserine lactones,N-AHLs),且均为革兰氏阴性杆菌。选取5株氧化酶阳性和5株氧化酶阴性菌经16S rDNA鉴定,这些腐败菌有假单胞菌(Pseudomonas spp.)和沙雷氏菌(Serratia spp.)。其中两株假单胞菌PP103和PP110经过生理生化鉴定,16S rDNA和carA基因特异片断系统发育分析确定为隆德假单胞菌(Pseudomonas lundensis),为进一步探讨AHLs对腐败菌蛋白酶表达的影响提供了研究基础。Abstract: Quorum sensing ( QS) maybe affect the proteolytic activity of spoilage bacteria which plays an important role in chilled pork spoilage.Fifty-four proteolytic bacteria were isolated form chilled pork with skim milk agar.Forty-four gram-negative strains of those isolates showed AHLs production capability in AHLs evaluation assay using Agrobacterium tumefaciens PELR4 as a biosensor strain. The results of identification of 10 strains ( 5 strains for oxidase positive and 5 for oxidase negative respectively) from 44 isolates base on 16S rDNA showed that oxidasepositive isolates were Pseudomonas spp., while oxidase-negative isolates were Serratia spp. With analyzing the combined data of phenotypic characteristics and phylogenetic analyses of 16S rDNA and carA, PP103 and PP110 were identified as Pseudomonas lundensis. The tow strains can be used for the further study on the relationship between AHLs and protease expression of spoilage bacteria.