Cloning,expression and characterization of sLAG-3-Ig

AIM: To obtain a vaccine with sLAG-3 as immunoadjuvant and investigate its biologic activity in order to establish the safe and effective way for asthma as one of the specific immunotherapy. METHODS: The coding sequence of LAG-3 was amplified by polymerase chain reaction, the expression vector pcDNA-sLAG-3-Ig was constructed by inserting the PCR products of sLAG-3 and Fc sequence of IgG. With electroporation transfection, pcDNA-sLAG-3-Ig was transfected into COS-7 cells and its biologic activity was investigated by Western blotting analysis. RESULTS: By temperature induction, the LAG-3-Ig was highly expressed in E.coli DH5α. LAG-3-Ig fusion protein was observed by SDS-PAGE and Western blotting, the results showed that the LAG-3-Ig protein was an antagonist of the IL-4-induced synthesis of IgE in B cells. CONCLUSION: A new vaccine with sLAG-3 as immunoadjuvant was obtained. It could inhibit synthesis of IgE in B cells. Thus, LAG-3-Ig would be hopeful to establish the safe and effective way for asthma as one of the specific immunotherapy.     

豆米轮作对春玉米土壤固氮细菌群落结构及多样性的影响

为探明大豆-玉米轮作对土壤固氮细菌的影响,以玉米连作为对照(MMM),以nif-H基因为指示,采用高通量测序技术,分析大豆-玉米2年轮作周期(MSM)和大豆-玉米-玉米3年轮作周期(SMM)下土壤固氮细菌群落结构及多样性。结果表明：大豆-玉米轮作下0～20、20～40 cm土层土壤有机质、全氮、碱解氮、铵态氮和硝态氮均显著增加。固氮细菌的Chao1指数和ACE指数在0～20、20～40 cm土层均为轮作高于对照,轮作下MSM显著高于SMM;Shannon指数和Simpson指数在0～20 cm土层轮作显著高于MMM;20～40 cm土层MSM显著高于MMM。在门水平上,MSM和SMM的0～20、20～40 cm土层变形菌门的相对丰度均高于MMM。在属水平上,2个轮作类型0～20 cm土层的慢生根瘤菌属、弗兰克氏菌属和纤毛菌属相对丰度显著较高;20～40 cm土层慢生根瘤菌属、伪食酸菌属、地杆菌属和固氮弧菌属相对丰度显著较高;MSM 0～20、20～40 cm土层慢生根瘤菌属、甲基孢囊菌属和固氮弧菌属较SMM均提高。方差分析表明,固氮细菌丰度指数（Chao1和ACE指数）与有机质、碱解氮...     

可食性涂膜保鲜技术研究进展

概述可食性涂膜的保鲜原理及主要成膜材料的种类和性质,综述了可食性涂膜保鲜技术在果蔬、肉制品、蛋、虾、食用菌等不同种类食品贮藏中的应用研究进展,提出目前存在的主要问题,展望了今后研究与应用的发展方向。     

抗生素在土壤中的吸附行为研究进展

抗生素是人类与动植物疾病防治中被广泛使用的抑菌或杀菌药物,由于其不能完全被机体吸收转化,大部分以原形或代谢物的形式经不同途径进入土壤环境,导致土壤微环境破坏,最终影响人类健康。本文通过文献查阅,综合近几年的研究现状,分析土壤矿物质、有机质、土壤溶液及土壤生物对抗生素吸附作用的机理,探究土壤矿物质、有机质、土壤溶液及土壤生物对抗生素吸附性能的影响,并对抗生素在土壤中的吸附行为进行了展望,以期为土壤中抗生素污染防治提供理论依据。