灿烂弧菌对厚壳贻贝免疫指标和消化酶活性的影响

为探究灿烂弧菌对厚壳贻贝免疫指标和消化酶活性的影响,用1×10~6、1×10~7、1×10~8个/mL 3个浓度的灿烂弧菌刺激厚壳贻贝,探讨弧菌刺激后厚壳贻贝的一氧化氮合酶(NOS)、一氧化氮(NO)、超氧化物歧化酶(SOD)、丙二醛(MAD)等免疫指标和淀粉酶、蛋白酶等消化酶的变化情况。结果显示,灿烂弧菌刺激48 h后,厚壳贻贝足、鳃、消化腺等组织中仅消化腺的NOS活性较对照组有显著升高,且酶活性随初始细菌浓度的升高而升高,故选用消化腺来测定灿烂弧菌刺激后72 h内的免疫指标和消化酶活性的变化。灿烂弧菌刺激后,48 h内NOS活性较对照组均显著升高。NO含量较对照组均显著升高,与NOS显现相同变化趋势。SOD活性在各浓度灿烂弧菌刺激下较对照组均显著升高,而MAD含量在实验组中含量显著低于对照组。淀粉酶活性在实验组中显著低于对照组,总体呈现先下降后升高的趋势。蛋白酶活性在各实验组中均呈现先升高后下降的趋势。研究表明,灿烂弧菌对厚壳贻贝免疫指标和蛋白酶活性的升高有诱导作用,但对蛋白酶的活性有抑制作用。本研究初步探明了厚壳贻贝对灿烂弧菌的免疫应答机制,为进一步研究灿烂弧菌和厚壳贻贝相互作用机制以及厚壳贻贝免疫机制奠定了基础。

Influence of Vibrio splendidus on immune indexes and digestive enzyme activity of Mytilus coruscus

Mytilus coruscus adults were challenged by Vibrio splendidus in three concentrations (1×10⁶ cell/mL, 1×10⁷ cell/mL, 1×10⁸ cell/mL). The changes of immune indexes including nitric oxide synthase (NOS), nitric oxide (NO), superoxide dismutase (SOD) and malondialdehyde (MAD), and digestive enzyme activities including amylase and protease in digestive gland were determined during 72 h experiment period. The activities of NOS in foot, gill and digestive gland were measured after experimental challenges of 48 h. Only the activity of NOS in the digestive gland was significantly different from the control group, and the activity of NOS increased with the increase of initial concentration of V. splebdidus. The activity of NOS of digestive gland in the treatment group was significantly higher than that of the control group after the challenge of V. splebdidu, and the level of NOS significantly increased after 48 h. The content of NO was significantly higher than that in the control group. The content of NO increased first and then decreased, which had a similar trend with the activity of NOS. The activity of SOD was significantly higher compared with that of the control group after the challenge of V. splebdidu. The content of MAD in the treatment group was significantly lower than that in the control group after the challenge of bacteria. The activity of amylase in the treatment group was significantly lower than that in the control group. The activity of amylase descended first and then increased. The change of protease activity in the treatment group increased first and then decreased. This study indicates that V. splebdidu can promote the immune indexes and protease activity and inhibit amylase activity. The present study provides useful information for clarifying the immune mechanism of M. coruscus and Vibrio-mussel interactions.