地衣芽孢杆菌(Bacillus licheniformis)对镉胁迫下泥蚶(Tegillarca granosa)的抗氧化酶活性和免疫相关基因表达的影响

本文研究一株地衣芽孢杆菌(Bacillus licheniformis)对提高泥蚶耐受镉(Cd2+)胁迫的作用,实验分析了不同浓度地衣芽孢杆菌对Cd2+胁迫下泥蚶(Tegillarca granosa)的存活率及组织中Cd残留量的影响;同时比较了地衣芽孢杆菌作用前后,泥蚶体内两类抗氧化酶,超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)的活性,进一步通过Real-time PCR分析了三类免疫相关基因金属硫蛋白(MT)、小热休克蛋白分子(sHSP)和铁蛋白(ferritin)的表达情况。研究结果显示,地衣芽孢杆菌能降低泥蚶组织中Cd残留量,提高其存活率。并能有效促进泥蚶体内SOD和GSH-Px酶活性的增加,同时降低MT、sHSP和ferritin在mRNA水平上的表达。数据表明该地衣芽胞杆菌可通过调节泥蚶的免疫系统,起到降低Cd2+对泥蚶毒害的作用。

INTAKE OF BACILLUS LICHENIFORMIS MEDIATES ANTIOXIDANT ENZYME ACTIVITIES AND GENE EXPRESSION IN CADMIUM-STRESSED TEGILLARCA GRANOSA

To assess the ability of Bacillus licheniformis in removing Cd from aquatic animals, Tegillarca granosa was used to test the effect of B. licheniformis intake on Cd removal, and the impacts on the survival, the activities of two antioxidant enzymes, and the expression levels of three genes in T. granosa that were co-administrated in Cd. Results show that B. licheniformis intake effectively reduced the Cd contents in visceral mass of T. granosa and increased the survival rates. Meanwhile, the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were significantly increased. However, the expression levels of metallothionein (MT), small heat shock protein (sHSP) and ferritin were all down-regulated in T. granosa fed B. licheniformis compared to the control. Therefore, B. licheniformis could protect T. granosa potentially and effectively from stress by reducing Cd toxicity and modulating the immune system of the host.