一种兴奋性氨基酸受体亚型

N-甲基-D-门冬氨酸(NMDA)受体是一种兴奋性氨基酸受体,广泛分布于许多脑区。该受体被激活后,突触后膜产生一长时程的兴奋性突触后电位,进而引起多种神经生物学效应或神经毒性作用。Ca~(2 )对于NMDA受体效应的产生具有重要意义。     

菠菜叶片过氧体甘氨酸转氨酶初探

菠菜叶片过氧体可转变甘油酸或羟基丙酮酸成为丝氨酸。以甘氨酸为氨基供体时,完整过氧体的转变活性比破碎的约高2.5倍,这不是由于完整的膜包被使有效的羟基丙酮酸浓度增加,或由于膜破碎使辅助因子损失,也不是由于过氧体膜的甘氨酸主动运输系统的作用。结果显示,在过氧体中存在甘氨酸转氨酶,完整过氧体中高的转氨速度可能是由于甘氨酸转氨酶在完整的和破碎的过氧体中的构象或构型不同。     

微管的冷稳定性与植物抗寒性关系的研究

利用间接免疫荧光的细胞化学技术对番茄、黄瓜、菠菜、甜菜及小麦等不同抗寒性植物微管的冷稳性进行了比较研究。结果指出,不抗寒的喜温性植物番茄和黄瓜的气孔保卫细胞的微管在0℃—1℃冷处理3小时即解聚;属于中等抗寒性植物的菠菜和甜菜幼苗经秋季低温锻炼后,其气孔保卫细胞的微管在0℃和—5℃低温处理3小时,均不发生解聚;具有较强抗寒性的冬小麦品种农大139幼苗在2—3℃低温锻炼期间,微管结构保持完整,经过15天低温锻炼的幼苗在-8℃冰冻处理3小时,微管也不受破坏。这些结果表明,微管的冷稳性与植物的抗寒性成正相关。     

西欧地中海地区中新世以来的植被演化和现代地中海植被的形成

从距今2500万年的中新世初到更新世,欧洲地中海沿岸地区的植被是从东亚型的热带——亚热带常绿阔叶林逐渐过渡为旱生性的蒿——藜草原。古热带和亚洲、北美成份从晚中新世起逐渐消失,少数一直延续到中更新世。孢粉分析表明,地中海成分从中上新世起有明显增加,地中海常绿硬叶林的发展与北极冰盖的形成密切相关。     

我国特有植物银杉的资源、分布及其环境

我国银杉自1955年发现以来,陆续发现了它的新分布,至今已知在四省、区7个分布区的30多个分布点上,自然生长着银杉3200余株。它们是:广西花坪林区(越城岭南部)6个点有银杉1040抹,其中高5米以上的68株,1～5米的49株,1米以下的923株,最高21.1米,最大胸径83厘米;广西大瑶山4个点有银杉143株,其中高10米以上的94株,1～3米的3株,1米以下的46株,最高30米,最大胸径79.2厘米;湖南罗汉洞(越城岭北部)2个点有银杉58株,5米以上的有45株,最高18米,最大胸径43厘米;湖南罗霄山脉八面山有银杉707株,高1米以上的334株,最高24米,最大胸径46厘米;四川南川金佛山(大娄山东段北部)6个点有银杉527株,其中成年树400余株,最高17米,最大胸径50厘米;百枝山有银杉52株,最高8米,最大胸径27厘米;贵州道真沙河林区(大娄山东段南部)3处12个点有银杉729株,其中高5米以上的105株,2～5米的209株,1～2米的111株,1米以下的304株,最高18.8米,最大胸径48厘米;贵州桐梓白菁有银杉10株,高4～5米的2株,1～3米的6株,1米以下的2株。 银杉分布区范围自北纬24°5′～29°13′14″,东经107°10′～113°40′。其垂直分布自海拔940～1840米,金佛山银杉分布最高,为1600～1840米;罗汉洞银杉分布最低,为940～1060米。分布区内,年均温8.2°～17℃,绝对最低温     

青海藏族青少年骨龄与生长发育关系研究

本文报告了青海省境内,世居在海拔3000-4000米地区的728名7-18岁健康藏族青少年学生的手、腕部骨骼发育情况,对骨化中心出现和骨骺愈合求出了50%出现年龄,并对骨龄与青春期身高突增的关系及与月经初衬潮的关系进行了分析。     

Folylpolyglutamate Derivatives of Pisum sativum L. Determination of Polyglutamate Chain Lengths by High Performance Liquid Chromatography Following Conversion to p-aminobenzoylpolyglutamates

The folypolyglutamate derivatives of pea seedlings (Pisum sativumL. cv. Homesteader) were extracted in the presence of 2-mercaptoethanoland cleaved to p-aminobenzoylpolyglutamates by treatment withZn-HCl. Azo dyes were formed by reaction with naphthylethylenediamine and purified by polyacrylamide gel chromatography. p-Aminobenzoylpolyglutamateswere regenerated from these dyes by Zn treatment and then concentratedin vacuo. These derivatives were separated according to glutamylchain length by high performance liquid chromatography on WhatmanPartisil SAX columns. The folylpolyglutamates of 4 day old peacotyledons, pea leaves and isolated chloroplasts were mainlytetra- and pentaglutamates. These and folates of shorter chainlength were labelled when seeds and aerial shoots were incubatedwith p-aminobenzoate-[¹⁴C]. Labelling of the pentaglutamatewas reduced in seeds that were imbibed in the presence of 0.1mM methotrexate. Studies of cotyledon folylpolyglutamate synthetaseshowed that polyglutamate chain length was affected by incubationtime and the concentration of tetra-hydrofolate monoglutamatein the reaction system. ¹Present address: Department of Biology, University of Lethbridge,Alberta, Canada T1K 3M4 ²Present address: Department of Horticulture, Xiong-yue AgriculturalCollege, Xiong-yue, Liaoning Province, China (Received August 4, 1989; Accepted December 5, 1989)     

Adult diarrhea rotavirus in Jilin, China

In May 1986, an outbreak of epidemic acute diarrhea occurred in one city and three counties in Yanbian area. The diarrheal cases were seen in all age groups, the majority of the cases were seen in adult age group. No bacterial pathogens were isolated in 22 fecal samples examined, however rotavirus like particles of 52-68 nm in diameter were found in 50% (11/22) of fecal samples by the immunoelectron microscopy using convalescent sera. Examination by the adult diarrhea rotavirus (ADRV) ELISA kit showed positive reaction in 86% (6/7) of fecal extracts, however in all 22 fecal extracts examination using ELISA kit for detection of group A rotavirus showed negative reaction. The PAGE patterns of viral RNAs similar to those of ADRV were seen in 13 out of 22 fecal extracts. The detection rate by PAGE analysis was 59%. Based on the above data, the etiological agent of the epidemic acute diarrhea, which occurred in Yanbian area, was identified to be ADRV.     

兔的一种新病毒：Ⅱ.一株兔出血症...

In this paper a strain of Rabbit Hemorrhagic Disease Virus (RHDV) was isolated and purified from the diseased rabbit livers with a method of using chloroform, two-phase of polyethylene-glycol-dextran sulfate sodium and sucrose density gradient centrifugation. Purified virus was nonenveloped, icosahedeal symmetry with a triangulation number of 3, and 33-37 nm in diameter. The capsid was composed of 32 capsomeres with central holes in an outer diameter of about 9nm. Two types of viral particles having different sedimentation coefficient, 130s and 166s could be identified after sucrose density gradient centrifugation. Probably no less than four virion proteins with molecular weight of 66.4, 65.0, 63.5, 41.0 x 10(3) dalton were detected by SDS-polyacrylamide gel electrophoresis. Viral nucleic acid was extracted from purified virus by using SDS-proteinase K-phenol. Tests with diphenylamine, formaldehyde, and staining with acridine orange as well as the curves of thermal denaturation showed that this kind of virus had a single-stranded DNA. The molecular weight of the ssDNA was approx 2.1 x 10(6) dalton as determined by electron microscopy. Data indicate that the RHDV may like the parvovirus of the family Parvoviridae.