环境因子对溶藻弧菌(Vibrio alginolyticus)粘附大黄鱼(Pseudosciaena crocea)表皮粘液影响的研究
ENVIRONMENTAL INFLUENCE ON ADHESION OF VIBRIO ALGINOLYTICUS TO SKIN MUCUS OF PSEUDOSCIAENA CROCEA
- 化学化工－已发表论文 
采用3H-TdR同位素示踪方法研究了环境因子对溶藻弧菌对大黄鱼表皮粘液粘附作用的影响。试验结果表明,溶藻弧菌能很好地粘附于大黄鱼表皮粘液,其粘附量在菌浓度不超过6.52×108cfu/ml情况下随菌浓度的升高而升高;粘附量在25℃下孵育180min趋于饱和,在180min以内与孵育时间呈正相关关系;粘附作用在温度25—30℃、pH值偏酸、盐度35条件下较强;在无Na+(盐度为0)时,无粘附作用;Ca2+能显著加强溶藻弧菌的粘附作用,而Mg2+作用不明显。这些结果表明,溶藻弧菌对大黄鱼表皮粘液有较强的粘附作用,其粘附作用受温度、盐度、pH值等环境因子的影响。Fish pathogens can colonize and infect the host by attaching bacteria onto host's mucus layer. Study on the attachment and adhesion of a pathogen is important to prevent the host from infection. In this paper, we study the case of pathogen Vibrio alginolyticus and host Pseudosciaena crocea (large yellow croaker) as an example for better understanding of adhesion of the pathogen to the skin mucus of the host. The mucus samples are extracted from P. crocea with protein concentration adjusted at 1mg/ml, using microtiter plate and methyl-3H thymidine as the isotope tracer. Our results show that the quantity of V. alginolyticus adhesion increases with bacteria concentrations at the equilibrium 180min post-incubation. However, quantity does not reach an equilibrium point when the bacterial concentration ranges from 0.044 to 1.11 (OD550) 90min after incubation at 25℃; incubation temperature is one of the main factors that affect the bacterial adhesion. V. alginolyticus shows stronger adhesion in warm condition reaching the maximum at 25℃. On the other aspect, pH value affects the bacteria adhe-sion remarkably. The adhesion is remarkably stronger at pH 3---5 than at pH 7---9, peaked at pH 6. The adhesion fluctuates in seawater with different salinities optimized at 3.5%. No specific adhesion of V. alginolyticus to skin mucus is exhibited in Na+-free solution. Existence of Ca2+ but Mg2+ can obviously promotes the adhesion. All the results suggest that the pathogenic V. alginolyticus can adhere to the skin mucus of P. crocea easily in seawater; however, environmental factors of temperature, pH and salinity can influence the adhesion effectively. The optimal condition is 25-30℃, pH about 6, and 3.5% in salinity.