维氏气单胞菌中AHLs介导的群体感应现象及大蒜提取物的干扰作用

AHLs Based Quorum Sensing in Aeromonas veronii bv.veronii and Its Interruption from Garlic Extract

以发酵鱼糜中分离的1株维氏气单胞菌为对象,分析该菌中N-酰基高丝氨酸内酯(AHLs)介导的群体感应现象,研究大蒜提取物作为群体感应抑制剂对该菌群体感应及腐败能力的干扰作用。结果表明,维氏气单胞菌至少产生3种AHLs信号分子,即C6-HSL、C7-HSL和C8-HSL。在细菌快速生长阶段,AHLs分子的活性不断增加;当细菌进入稳定期后,AHLs活性开始降低。在亚抑菌浓度下,大蒜提取物对维氏气单胞菌的AHLs产生和生物膜形成有抑制作用。经1.20 mg/mL大蒜提取物处理,β-半乳糖苷酶活性和成膜量分别降低了39.6%,36.7%,luxRI同源基因(acuRI)、鸟氨酸脱羧酶基因(ODC)、弹性蛋白酶基因(ahyB)、丝氨酸蛋白酶基因(ser)和鞭毛基因(fla)的基因表达量均显著下调(P<0.05)。此外,大蒜提取物能显著减少鱼糜肉汁中TVB-N和腐胺含量的累积(P<0.05),说明大蒜提取物通过阻断维氏气单胞菌的群体感应系统降低其腐败能力。

In the present study,we investigated the acylated homoserine lactones(AHLs)based quorum sensing(QS)system in Aeromonas veronii bv.veronii isolated from fermented surimi,and the interruption of AHLs production,virulence factors and food spoilage potential by garlic extract,an anti-QS agent.The results showed that A.veronii bv.veronii was able to produce at least three types of AHLs,including C6-HSL,C7-HSL and C8-HSL.AHLs activities increased during the rapid growth stage,and then decreased when it entered the stable growth phase.The garlic extract treatment was found to attenuate the AHLs production and biofilm formation of A.veronii bv.veronii under minimum inhibitory concentration.At a garlic extract concentration of 1.20 mg/mL,the inhibition ofβ-galactosidase activity and biofilm formation reached 39.6%and 36.7%,respectively.After garlic treatment,genes including luxRI homologs(acuRI),ornithine decarboxylase(ODC),serine protease(ser),elastase(ahyB)and flagellin(fla)were down-regulated.Furthermore,it was inferred that the garlic extract could inhibit the spoilage potential of A.veronii bv.veronii,since the production of total volatile base nitrogen(TVB-N)and putrescine in surimi were decreased.