一株分离自美国龙虾的麦氏弧菌的鉴定及其低温状态下细胞脂肪酸的变化

摘要

[目的]对从美国龙虾(Homarus americanus)中分离的菌株F5-1进行种属鉴定并分析其低温状态下脂肪酸组成变化.[方法]通过VITEK 2 Compact全自动微生物鉴定仪分析菌株的生理生化特征和进行药敏试验；16S rRNA基因序列同源性分析确定该菌株的系统发育学地位；通过气相色谱和质谱联用法(GC-MS)分析菌株的全细胞脂肪酸.[结果]菌株F5-1为革兰氏阴性菌,对弧菌抑制剂O/129敏感,对青霉素有耐药性；生理生化特征与麦氏弧菌(Vibrio metschnikovii)的相似性为96％,16S rRNA序列与麦氏弧菌(GenBank No.HQ658055)的相似性为99％；菌株的主要脂肪酸组成为C12∶0、C14∶0、C16∶0和C16∶1(n-7),不饱和脂肪酸(棕榈油酸)相对含量达34％,低温培养状态下,不饱和脂肪酸(棕榈油酸)相对含量增加至40％.[结论]将美国龙虾中分离的菌株F5-1鉴定为麦氏弧菌,该菌对多种药物敏感,菌细胞脂肪酸组成与来源于俄罗斯海参威某饮用水水库中分离的麦氏弧菌有较大差异.%[Objective] Bacterial strain F5-1 isolated from the Homarus americanus was characterized and its changes in membrane fatty acid composition in response to low temperature were also studied.[Methods] The physiological and biochemical characteristics were carried out by using VITEK 2 compact automated microbiology system.The 16S rRNA gene was sequenced and subjected to phylogenetic analysis.Fatty acids were detected by gas chromatography-mass spectrometry (GC-MS).[Results] Strain F5-1 was Gram-negative and susceptible to the vibriostatic agent O/129.Strain F5-1 was resistant to Penicillin.The isolated strain exhibited the highest levels of 99％ probability to Vibrio metschnikovii based on the conventional physiological test.The sequence analysis of 16S rRNA gene of F5-1 isolation and comparison with that of other related vibrios showed that F5-1 was very close to V.metschnikovii (GenBank No.HQ658055).The similarity was 99％.The major fatty acids were C12∶0,C14∶0,C16∶0 and C16∶ 1(n-7).Palmitoleic acid was the dominant unsaturated fatty acids.The major change in fatty acid composition occurred in response to low temperature,with an increase in palmitoleic acid from 34％ to 40％.[Conclusion] Bacterial strain F5-1 isolated from Homarus americanus was identified as V.metschnikovii and was sensitive to multiple drugs.The fatty acid composition of F5-1 was different from V.metschnikovii isolated from a drinking water reservoir near Vladivostok City in the Russia Far East.Results of this study indicated that environmental conditions allowed modulation of the fatty acid composition of V.metschnikovii.