b-1,3-葡聚糖对副溶血弧菌感染菲律宾蛤仔(Ruditapes philippinarum)的存活及两种免疫基因表达影响

Effects of β-1,3-Glucan on the Survival and Expression of Two Immune Genes in Ruditapes philippinarum Infected with Vibrio parahaemolyticus

中文关键词: b-葡聚糖  菲律宾蛤  副溶血弧菌  免疫基因

英文关键词: Beta-glucan  Ruditapes philippinarum  Vibrio parahaemolyticus  Immune gene

中文摘要:

      本文以菲律宾蛤仔(Ruditapes philippinarum)为材料，开展了不同浓度b-1,3-葡聚糖对正常菲律宾蛤仔及副溶血弧菌(Vibrio parahaemolyticus)感染后蛤仔的存活率和凝集素基因(Lectin)、Toll样受体2基因(TLR2)的表达研究。结果显示，b-葡聚糖浸泡蛤仔可以有效提高副溶血弧菌感染后蛤仔的存活率，在1000 mg/L浓度下，存活率最高，未感染组的鳃组织中，TLR2在6 h时达到峰值，显著高于其他时间(P<0.05)。在感染组中，TLR2呈先升高后降低的趋势，在1.5 h时达到峰值。感染组和未感染组的Lectin表达均为先升高后下降趋势。在3 h时，100 mg/L未感染组的Lectin相对表达量显著高于100 mg/L感染组(P<0.05)。在外套膜中，感染组和未感染组TLR2在3~12 h之间表达量逐渐降低。在24 h时，1000 mg/L未感染组表达量最高。感染组Lectin在外套膜中，浓度为1000 mg/L的实验组比100 mg/L实验组各时段都有更高的表达量，但只有0和24 h时差异显著(P<0.05)。蛤仔鳃和外套膜Lectin的表达模式不同，但b-葡聚糖的浸泡都促进了Lectin在感染初期的表达。从结果上看，b-葡聚糖的浸泡会增加这2种基因的相对表达，被b-葡聚糖浸泡过的蛤仔被副溶血弧菌感染后，会更为快速地表达TLR2和Lectin。本研究旨在通过不同浸泡浓度b-葡聚糖对蛤仔存活及免疫基因表达的影响，初步了解b-葡聚糖对蛤仔免疫力的作用，为蛤仔亲贝的保种、苗种繁育及池塘养殖的疾病防控提供一定的理论依据。

英文摘要:

      In this study, the effect of beta-glucan on survival rates and the mRNA expression of Lectin and TLR2 in both uninfected and infected Manila clams Ruditapes philippinarum were studied. The results showed that beta-glucan could effectively improve the survival rate of Manila clams infected by Vibrio parahaemolyticus. The survival rate was highest at a beta-glucan concentration of 1000 mg/L. In the gill tissues of the uninfected group (A1 and A2), the TLR2 peaked at 6 h, which was significantly higher than that of other times (P<0.05). In the infected group, TLR2 increased to a peak at 1.5 h and then decreased. Lectin expression in both the infected and the uninfected group increased first and then decreased. The relative expression of Lectin in the A1 group was significantly higher than that of the B1 group at 3 h (P<0.05). In the mantle, the expression of TLR2 in both infected and uninfected groups decreased gradually between 3~12 h. At 24 h, the expression of group A2 was highest. However, in the infected group, the expression of Lectin in 1000 mg/L beta-glucan was higher than at 100 mg/L in the mantle, but there was only a significant difference at 0 h and 24 h (P<0.05). The expression patterns of Lectin in the gill and in the mantle were different, but the feeding of beta-glucan promoted the expression of Lectin during the early stages of infection. From these results, beta-glucan soaking can increase the relative expression of the two genes, and TLR2 and Lectin are expressed more quickly after infection by V. parahaemolyticus when soaked with beta-glucan. The aim of this study is to understand the dose dependent effect conferred by beta-glucan on the immune system and the survival rate of Manila clams, which might provide some theoretical basis for the stock culture, seed breeding and disease control in pond culture of Manila clams.