将哈维氏弧菌SF1接种在自然海水中低温诱导进入活的非可培养状态,用添加营养物质后升温培养的方法进行复苏。用透射电镜观察不同状态哈维氏弧菌细胞形态和结构,研究哈维氏弧菌复苏后对不良环境的抵抗力,用RT-PCR检测丝氨酸蛋白酶基因Ser和rpoS基因的表达。结果表明,进入VBNC状态的哈维氏弧菌由杆状变为球状,体积比正常细胞小,复苏后恢复正常形态且对紫外辐射,热激的抵抗能力没有明显改变,对高渗透压的抵抗力减弱,而对冷激的抵抗力增强。复苏后的哈维氏弧菌对抗生素的敏感性没有改变。用RT-PCR未检测到在VBNC状态时Ser和rpoS基因的表达,而在复苏后的细胞均检测到该基因的表达,可能是其保持致病性的重要原因之一。
Vibrio harveyi SF1 cells were incubated and induced into viable but nonculturable state in sterilized seawater at 4℃.The VBNC cells were resuscitated with temperature increase in nutrition of yeast extract by adding Tween 20 or compound vitamin B.The morphological changes of VBNC cells and resuscitative cells were studied in transmission electron microscopy.Physiological responses of the resuscitative cells to UV,heat (42℃),cold (4℃) and osmotic stresses (2.5mol/L NaCl) were determined.Reverse transcription-polymerase chain reaction (RT-PCR) was used to identify expression of virulence related Ser and rpoS genes of the resuscitative cells.Sensitivity of the resuscitative cells to 26 antimicrobial agents did not change obviously when compared with that of the control.The expressions of Ser,rpoS genes were not detected in the VBNC cells but in the resuscitative cells.Virulence related genes were expressed in the resuscitative cells,which may partly explained the retaining of the pathogenicity of the resuscitative V.harveyi.