基于发光细菌法的农产品中主要重金属的联合毒性评价

通过细菌发光抑制试验,研究Pb^(2+)、Cd^(2+)和Hg^(2+)的单一毒性,以及Pb^(2+)+Cd^(2+)、Cd^(2+)+Hg^(2+)、Pb^(2+)+Hg^(2+)、Pb^(2+)+Cd^(2+)+Hg^(2+)的混合毒性,分别采用等毒性单位法与加和指数法,对其混合物的联合毒性进行评价。结果表明,3种重金属的毒性大小为Hg^(2+)>Pb^(2+)>Cd^(2+)。对于混合体系,两种评价方法结果一致,即Pb^(2+)+Cd^(2+)为协同作用;Cd^(2+)+Hg^(2+)、Pb^(2+)+Hg^(2+)和Pb^(2+)+Cd^(2+)+Hg^(2+)均为拮抗作用。

重金属与四环素类抗生素对发光菌的毒性研究

本研究以发光细菌Photobacterium kishitanii为模式生物,通过发光抑制试验研究了5种重金属与四环素类抗生素对发光细菌的急性单一毒性与联合毒性。利用毒性单位法(TU法)表征联合毒性,并采用浓度加和模型(Concentration addtion,CA模型)与独立作用模型(Independent action,IA模型)预测二元混合体系对发光细菌的联合急性毒性。研究表明:单一毒性大小排序为硝酸铅>七水硫酸锌>氯化镉>盐酸土霉素>盐酸金霉素>盐酸强力霉素>盐酸四环素>五水硫酸铜>重铬酸钾。重金属之间的联合毒性主要表现为协同作用,重金属与四环素类抗生素的联合毒性主要表现为相加作用和拮抗作用,四环素类抗生素之间的联合毒性主要表现为拮抗作用。研究表明,重金属与四环素类抗生素共存会对发光细菌产生不同的毒性效应,因此在评价环境复合污染时应考虑联合毒性效应。

Immune Effect of Combination of Universal Molecular Adjuvant and IBDV Subunit

In order to evaluate the immune effect of the protein expressed by the universal vector pET-mLTA-CTLA-4 plus IBDV subunit, the fusion protein mLTA-CTLA-4 was expressed and purified. Protein toxicity tests were carried out on rabbits.The VP2 gene of infectious bursal virus was amplified by RT-PCR, and lately used for pET-VP2 construction. Ten-day-old free healthy chickens were chosen for a grouped test, including the mLTA-CTLA-4（at different doses） plus VP2 groups, IBDV living vaccine group and control group. Serum and mucosal samples were collected regularly and the neutralization titers of IgG and IgA were assayed, while an animal protection test was conducted to determine the protection rate. The results showed that the protein m LTA-CTLA-4 was non-toxic and its protection rate was100%. IgG or IgA levels in the IBDV vaccine group were slightly higher than those in recombinant protein groups. These results indicated that the recombinant protein mLTA-CTLA-4 could be applied with IBDV subunit vaccine to protect chickens from infection.