低温环境中 T-2毒素降解菌的分离鉴定及特性研究

摘要

T-2 toxin degradable bacteria( TTDB)in low-temperature environment was Isolated and screened and found out its biochemical characteristics,and probed deeply into its microbiological and biochemical features of simi-lar and dissimilar points,to provide reference for biochemical judgment during the inspection with TTDB. Aiming at exposure of low concentration T-2 toxin standard sample to - 20 ℃ low temperature environment T-2 standard toxin of low concentration,LC-MS / MS was adopted to quantitatively analyze the residual amount of T-2 toxin,using NA and PDA media,and isolated five degradable bacteria,they were identified as Bacillus vallismortis,Pseudomonas geniculata,Staphylococcus nepalensis,Bacillus cereus,and Enterobacter cloacae according to 16S rDNA and their bio-chemical characteristics,all can degrate low concentration T-2 toxin in different degrees at - 20 ℃ ,among them B. cereus had the strongest degradation with the rate as high as 91% . They have many similarities in physicochemical property,all of them cannot utilize D-tagatose(dTAG),exhibited negative to ELLMAN. B. vallismortis Bp1234-7, P. geniculata Bp24-4,S. nepalensis Bp124-5 and E. cloacae Bp123-7 decompose D-glucose,while B. cereus Bp123-7 does not.%离筛选低温环境中 T-2毒素的降解菌并探明其生化特性，探究 T-2毒素降解微生物生化特性异同点，为 T-2毒素降解微生物的检验提供生化判断参考。针对暴露于-20℃低温环境中的低浓度 T-2毒素标准品，采用 LC-MS/ MS 定量分析 T-2毒素残留量，利用营养琼脂培养基（NA）和马铃薯葡萄糖琼脂培养基（PDA）共分离出5株降解菌，16S rDNA 结合生化鉴定结果为死谷芽胞杆菌（Bacillus vallismortis）、蜡状芽胞杆菌（Bacil-lus cereus）、阴沟肠杆菌（ Enterobacter cloacae）、弯曲假单胞菌（ Pseudomonas geniculata）和尼泊尔葡萄球菌（Staphylococcus nepalensis）。这些分离株在-20℃条件下对低浓度 T-2毒素均有不同程度的降解能力，其中蜡状芽胞杆菌（Bacillus cereus）降解能力最强，降解率为91%。它们的理化特性具有很多相似性，主要表现在5株菌均不能利用 D-塔格糖（ dTAG），对 ELLMAN 都表现出阴性；Bacillus vallismortis Bp1234-7、Pseudomonas geniculata Bp24-4、Staphylococcus nepalensis Bp124-5和 Enterobacter cloacae Bp123-7都能分解 D-葡萄糖，而 Bacil-lus cereus Bp1234-8不能。