促性腺素释放激素(GnRH)的作用机制

促性腺素释放激素(GnRH)通过受体机制对垂体促性腺细胞分泌促卵泡素/促黄体素(FSH/LH)进行调控.在整个细胞信号转导过程中,它与G蛋白结合受体家族Gq/11结合,导致一系列不同信号在细胞内传导,其中细胞内外Ca2+的释放、PKC的激活JNK激活以及小分子G蛋白(Ras)的激活起到了关键性的作用.最终引起细胞内GnRH受体合成、LH/FSH合成和分泌、细胞生长、分化和增殖等生物学效应.     

THE MECHANISM OF THE VIRUCIDAL ACTION OF ASCORBIC ACID

The theoretical yield of H(2)O(2) formed during the oxidation of a virucidal solution of ascorbic acid approximates the virucidal action of an equivalent amount of H(2)O(2). Both the action of ascorbic acid and H(2)O(2) are completely neutralized by catalase. The action of ascorbic acid against influence A virus may therefore be explained as being due to the H(2)O(2) formed during the Cu catalyzed oxidation of ascorbic acid. The observed in vitro virucidal activity of ascorbic acid obviously can not be utilized therapeutically because of the presence of catalase in body tissues.     

THE MECHANISM OF ACTION OF ALLOXAN ON BLOOD SUGAR

It has been found that an anti-penicillinase immune serum can be produced, in rabbits by the use of purified penicillinase as the antigen. Anti-penicillinase serum is suggested as protection for penicillin from inactivation by penicillinase.     

新型油乳剂与莠去津混用时作用机理的研究

本文从药液物理性状测定、电镜观察、植物光合作用和电导率的测定诸方面研究了新型油乳剂与莠去津混用时的作用机理。结果表明,新型油乳剂明显地降低莠去津喷雾液的表面张力和接触角,延长药液的干燥时间,增加药液在杂草叶表面的滞留,并破坏稗草叶表面的蜡质层,提高对莠去津的渗透和吸收,增加杂草叶部外渗液的电导率,加速莠去津对杂草光合作用的抑制,最终导致杂草快速死亡。     

多效唑对水稻生长发育及其作用机制的研究

多效唑(MET)处理水稻植株后,使株高降低,分蘖增多,穗粒数下降,与此相应,植株体内的赤霉素(GA_3),生长素(IAA)、玉米素(Z)显著下降,脱落酸(ABA)显著增加。用生长调节剂 GA_3和氮肥可逆转多效唑的抑制作用而便株高增加,给受抑制植株施用GA_3和 IAA,可使植株内 GA_3和 IAA 含量相应上升。因此 MET 可通过调节植株体内 GA_3、IAA、Z、ABA 的含量调控植物生长     

STUDIES ON THE MECHANISM OF ANTIBACTERIAL ACTION OF 2-METHYL-1,4-NAPHTHOQUINONE

Thioglycolic acid neutralized with sodium carbonate, sodium thioglycolate (Eastman), ethyl mercaptan, cysteine hydrochloride and certain sulfur-containing reducing agents (sodium bisulfite and sodium hydrosulfite) antagonize the antibacterial action of 2-methyl-1,4-naphthoquinone on Escherichia coli in a synthetic medium. Other reducing agents such as stannous chloride, potassium formate and sodium thiosulfate, show no such antagonism. The antibacterial activities of 2-methyl-3-chloro-1,4-naphthoquinone and 2,6-dimethyl-1,4-naphthoquinone are also abolished by excess thioglycolate and cysteine, while that of 2-methyl-3-methoxy-1,4-naphthoquinone with -OCH(3) instead of -Cl or -H in the 3 position on the quinone ring, is not. These findings suggest that the mode of antibacterial action of 2-methyl-1,4-naphthoquinone is by blocking essential enzymes through combination with sulfhydryl groups, or through combination with sulfhydryl groups of essential bacterial metabolites. This combination may take place in the 3-position on the quinone ring. This mode of action is similar to that suggested by other investigators for several antibiotic agents including penicillin. The antibacterial activity of the methoxy quinone, however, even in the presence of sulfhydryl groups, suggests that the foregoing explanation may not be the complete one.     

MECHANISM OF SULFONAMIDE ACTION. II. INHIBITION OF BACTERIAL RESPIRATION BY SULFANILAMIDE AND BY ITS INACTIVE ISOMERS

These data indicate that the inhibition of bacterial respiration is not a suitable criterion for the presence or absence of true sulfonamide activity.     

吡虫啉防治稻飞虱等害虫的毒理和技术研究

】１９９１～１９９７年系统研究了吡虫啉防治稻飞虱、多种作物蚜虫、稻象甲、稻瘿蚊、梨木虱、柑桔潜叶蛾等３０余种重要害虫及７种病毒病的毒理、应用策略和技术,在１９个省（市、区）示范应用３３９．２万ｈｍ２,取得直接经济效益１６．９４亿元,投入产出比达１３１,降低我国防治稻飞虱、蚜虫等用药量的８０％～９５％,并取得从毒理到应用技术多方面的创新。揭示了吡虫啉作用动力学过程中独特的正反馈机制,与害虫中枢神经受体低能态高度竞争性结合的热力学机制,显著的正温效关系,对家蚕无薰蒸毒性以及在植株中的内吸传导特性等。首创吡虫啉低量使用技术,为国外推荐量的１／１０～１／６,发现其高效防治稻瘿蚊、二化螟、小猿叶虫、梨木虱、恶苗病等,发展吡虫啉应急防治稻飞虱高龄种群、种子处理综合防治水稻前中期多种病虫害等关键技术。     

拮抗青枯病90B4-2-2菌株作用机理探讨

细菌９０Ｂ４－２－２对茄果类作物青枯病和烟草于枯病等有良好的防效。研究表明,经９０Ｂ４－２－２菌液处理的番茄种子的发芽势及植株茎的粗壮度分别是对照的１．２３倍和１．０６倍,番茄青枯病防效达７０％～８０％,增产１１％左右;该菌能够在植物体内繁殖,并表现出对番茄种子（浸种）具有发芽势高、健株防病和增产作用。