Further Evidence for Multiple Forms of an N-Methyl-d-Aspartate Recognition Domain in Rat Brain Using Membrane Binding Techniques

Abstract— Pretreatment with sulfhydryl-reactive agents, such as N-ethylmaleimide and p-chloromercuriphenylsul-fonic acid, invariably resulted in marked inhibition of the binding of dl -(E)-2-amino-4-[³H]propyl-5-phosphono-3-pentenoic acid ([³H]CGP 39653), a competitive antagonist at an N-methyl-d -aspartate (NMDA)-sensitive subclass of central excitatory amino acid receptors, in brain synaptic membranes extensively washed and treated with Triton X-100, but did not significantly affect the binding of L-[³H]-glutamic acid ([³H]Glu), an endogenous agonist. The pre-treatment was effective in reducing the binding of [³H]-CGP 39653 at equilibrium, without altering the initial association rate, and decreased the affinity for the ligand. Pretreatment with sulfhydryl-reactive agents also enhanced the potencies of NMDA agonists to displace [³H]-CGP 39653 binding and attenuated those of NMDA antagonists, but had little effect on the potencies of the agonists and antagonists to displace [³H]Glu binding. The binding of both [³H]CGP 39653 and [³H]Glu was similarly sensitive to pretreatment with four different proteases in Tritontreated membranes, whereas pretreatment with phospho-lipase A₂ or C markedly inhibited [³H]CGP 39653 binding without altering [³H]Glu binding. Moreover, both phospho-lipases not only induced enhancement of the abilities of NMDA agonists to displace the binding of [³H]CGP 39653 and [³H]Glu, but also caused diminution of those of NMDA antagonists. These results suggest that both sulfhydryl-reactive agents and phospholipases may predominantly interfere with radiolabeling of the NMDA recognition domain in a state favorable to an antagonist by [³H]CGP 39653, with concomitant facilitation of that in an agonist-preferring form by [³H]Glu. The possible presence of multiple forms of the NMDA recognition domain is further supported by these data.     

伴刀豆球蛋白A和层粘连蛋白与膜受体结合下膜分子运动及微丝组装变化的比较

研究伴刀豆球蛋白A和层粘连蛋白分别与小鼠腹腔巨噬细胞膜受体结合下引起细胞膜分子运动的变化和对微丝组装的影响.结果表明,伴刀豆球蛋白A和层粘连蛋白作用下均导致膜表面蛋白分子的侧向扩散速率减慢,膜脂流动性降低,加快膜内微丝组装并使微丝含量增加.两配体作用下引起细胞上述反应有相似性.     

芦笋皮层组织培养植株再生

报道了芦笋皮层组织培养再生植株的方法。表明：皮层在ＭＳ＋１ｍｇ／Ｌ２,４—Ｄ＋２ｍｇ／Ｌ６—ＢＡ培养基上形成无色或淡绿色疏松型愈伤组织,而ＭＳ＋２ｍｇ／Ｌ６—ＢＡ＋０．１ｍｇ／ＬＩＡＡ培养基则对芽的分化有利;试管苗的生很壮苗以无激素的ＭＳ为最佳培养基。此外,本试验还研究了不同碳源、不同激素组合对芦笋皮层离体培养再生植株的影响。     

中国种子植物区系定量化研究 V．区系相似性

本文总结了应用相似系数即关联系数进行植物区系相似性分析的现状,指出了存在的问题．然后,从集合论角度讨论了区系相似性、相似关系及其相似系数的实质．作者以为在区系相似性分析中应用Ｒ．Ｒ．Ｓｏｋａｌ和Ｃ．Ｄ．Ｍｉｃｈｅｎｅｒ（１９５８）提出的简单匹配系数比较适宜,同时亦能避免以往区系相似性分析中缺乏可比性及某些“表相”相似等问题．最后,还提出了总体相似系数和类型相似系数二个新概念,以便按照吴征镒教授关于中国植物区系研究的学术思想统一研究各个不同地区植物区系的相似性．对此,作者用了６个区系实例进行了演算说明．     

EB病毒转化Hu－TLC－SCID小鼠脾细胞的实验研究

利用ＥＢ病毒转化可产生较高水平人ＩｇＧ和特异性抗２型登革病毒人抗体的Ｈｕ－ＴＬＣ－ＳＣＩＤ小鼠脾细胞,通过免疫组化、免疫荧光和ＰＣＲ法检测转化细胞的人Ｂ细胞表面标志、ＥＢ病毒抗原和ＥＢ病毒基因。结果表明,被转化的Ｈｕ－ＴＬＣ－ＳＣＩＤ小鼠脾细胞能继续产生抗２型登革病毒的特异性人抗体,并具有人Ｂ细胞的、ＳｍＩｇＧ标志及ＥＢ病毒潜伏膜蛋白－１（ＬＭＰ－１）基因,可表达ＬＭＰ－１和ＥＢ病毒核抗原（ＥＢＮＡ）。     

抗生素对双歧杆菌影响的观察

本文观察了双歧杆菌对临床常用抗生素的敏感性及其Ｌ型形成和抗生素对动物体内双歧杆菌的影响,发现双歧杆菌对多种抗生素耐药或易形成Ｌ型。动物口服双歧杆菌同时给抗生素,６天后其粪便中仍有大量双歧杆菌或双歧杆菌Ｌ型存在,表明双歧杆菌可通过多种机制逃避抗生素的作用,在机体肠道内长期存在。     

The mechanism for the effect of selenium supplementation on immunity

Lipid peroxide (LPO) in lymphocytes from mice was evaluated by measuring substances reactive to thiobarbituric acid (TBA). The product resulting from the reaction of TBA with lymphocytes was extracted with n-butyl and fluorescence intensity was determined. The degree of lipid peroxidation, expressed as fluorescence intensity f547, was assessed for stimulation of lymphocytes with concanavalin A (Con A), and was related to lymphocyte proliferation in response to Con A if Se was administered. The lymphocyte proliferation was determined by [³H]thymidine incorporation, expressed as cpm. The effect of superoxide dismutase (SOD), added to cell culture on lymphocyte proliferation was also evaluated. It was found that LPO in lymphocytes before Con A stimulation was significantly less than that after stimulation (p<0.001), and that SOD promoted lymphocyte proliferation dose dependently. The addition of Na₂SeO₃ to lymphocyte culture or supplementation in drinking water to mice decreased the produced LPO in lymphocyte in response to Con A. In the presence of Se, there is an inverse correlation between the levels of LPO in lymphocyte and the stimulated proliferation (r=−0.8902,r=−0.9439). In conclusion, active oxygen species scavenging was proposed as one of the mechanisms for Se to promote immunity.