长叶车前花叶病毒(HRV_(sh))外壳蛋白赖氨酸残基的修饰

我们曾报道长叶车前花叶病毒上海分离株(简称HRVsh)的外壳蛋白有二个赖氨酸残基,在PH8.5无变性剂存在的条件下,完整病毒颗粒表面的赖氨酸残基可与三硝基苯磺酸(TNPS)起反应,反应后的TNP-HRVsh病毒颗粒的感染力丧失达90％以上。 本文又进行了甲基乙亚胺甲酯(MEI)对HRVsh赖氨酸残基的修饰反应,修饰后的MEI-HRVsh病毒颗粒的感染力也同样丧失90％以上。 从三硝基苯磺酸修饰的病毒颗粒(TNP-HRVsh)中分离得到的RNA能与天然的HRVsh的外壳蛋白重建病毒颗粒,并具有感染力,说明修饰过程中核酸并不受影响。 进一步用同位素~(35)S,~(32)P双标记病毒,再以TNPS修饰标记的病毒,得到(~(35)S,~(32)P)-HRVsh及TNP-(~(35)S,~(32)P)-HRVsh。将两者分别接种于系统寄主青菜(Brassica chinensis)的一片叶片,一天后在非接种叶片上都可测得~(35)S,~(32)P的放射计数。其中,(~(35)S,~(32)P)-HRVsh的~(35)S/~(32)P比值降低了,而TNP-(~(35)S,~(32)P)-HRVsh的~(35)S/~(32)P比值保持不变。说明HRVsh外壳蛋白赖氨酸残基的修饰并不影响病毒颗粒进入寄主细胞,以及在寄主细胞间的转移。同位素双标记的结果表明,其感染力丧失的原因可能是由于上述修饰作用阻止了病毒在感染中所必须的脱壳过程。     

Comparison of male adult population densities of the oriental and artocarpus fruit flies,Dacus spp. (Diptera: Tephritidae), in two nearby villages in Penang,Malaysia

The populations of native male adult oriental fruit fly Dacus dorsalis (Hendel ) and artocarpus fruit fly D. umbrosus (F.) in two selected site (BU and SD) were estimated weekly by the capture-recapture technique using live traps baited with methyl eugenol. In BU where many varieties of fruit trees were grown, the estimated population densities of D. dorsalis were between 980 and 3100 male flies per ha between May and July, 1984. During the same period, in SD where there were fewer number and varieties of fruit trees, the estimated population densities were between 300 and 1000 flies per ha. The estimated population densities of D. umbrosus over the same period were between 570 and 1290 flies per ha in BU; and between 5 and 95 flies per ha in SD. Of a total 6828 marked D. dorsalis flies released only one fly (released 6 weeks earlier in BU) was caught in a different site.     

体外分化的人体巨噬细胞抑制天然杀伤(NK)细胞的研究

本文继先前工作后,进一步应用正常健康人外周血单个核细胞(PBMNC)经塑料培皿粘附技术把单核细胞分离出来,经培养进一步纯化,随后动态观察培养0,2,4,6和8天的单核-巨噬细胞的形态变化和对新鲜分离同种异基因个体PBMNC中NK活性的影响。实验表明,体外分化6天和8天的巨噬细胞质/核比例和胞浆内空泡显著增加,细胞直径约为0天时的2倍。这些细胞和PBMNC之比为0.5:1时,引起了NK细胞活性的50%以上抑制(4小时~(51)Cr标记K 562肿瘤的同位素释放试验)。这种抑制效应不为过氧化氢酶(Catalase 4000单位/毫升)和前列腺素合成酶的抑制剂(Indom 1×10~(-5)M)所阻断。实验证明,同种异基因个体的NK细胞不能识别巨噬细胞表面抗原,从而排除了巨噬细胞和K562肿瘤抗原竞争的可能性。实验还表明,巨噬细胞对NK活性的抑制是不受HLA约束的。应用高频超声振荡破碎巨噬细胞膜方法和免疫调变技术进一步提示,人体巨噬细胞对NK活性的抑制与巨噬细胞体积无关,而与体外分化所赋有的固有特性和它们分泌的免疫调节分子有关。     

Transplantation of cultured thymic fragments. VI. H-2 recombinant donors

Athymic (nude) mice were transplanted with cultured thymic fragments from syngeneic, allogeneic, and partially allogeneic (recombinant) mice. Lymphocyte proliferation and cytotoxicity in vitro were measured to assess immunologic reconstitution. Transplanted nude mice were immunocompetent whether donor and recipient were disparate for class I, class II, or both H-2 gene types. Furthermore, allotolerance for thymic H-2 class I antigens was achieved independently of class II antigen allotolerance. Class I antigen tolerance was not broken during lymphocyte responses to unrelated alloantigens, ruling out insufficient help as the tolerance mechanism. Splenocytes, isolated from nude mice transplanted with fully allogeneic or syngeneic thymic fragments and stimulated in vitro with trinitrophenyl-modified cells, displayed H-2-restricted, hapten-specific cytotoxicity. Cytotoxic cells from allotolerant mice were restricted to either host or thymic H-2 antigens, depending on the stimulating cell haplotype. Response levels for thymic and host trinitrophenyl-modified cells were comparable. We have shown that allogeneic thymic epithelium transplanted into adult nude mice can induce allotolerance to class I and II H-2 antigens equally, and permits T lymphocyte interaction with cells bearing thymic donor or host H-2 antigens. Our results are consistent with a model wherein T lymphocyte self-receptors retain their genomic repertoire but can be selectively mutated or expanded by appropriate H-2 antigen presentation by the thymus.     

Effects of p,p''-DDT on the Rat Brain Concentrations of Biogenic Amine and Amino Acid Neurotransmitters and Their Association with p,p''-DDT-Induced Tremor and Hyperthermia

Male, Fischer strain 344 adult rats were given various doses (25-100 mg/kg) of p,p'-DDT by oral gavage, and levels of biogenic amines, their metabolites, and amino acid neurotransmitters, tremor activity, and rectal temperature were measured at several intervals (2, 5, 12, and 24 h) after dosing. Dose-related increases in rectal temperature and in tremor activity were observed at 50-100 mg/kg 12 h after dosing. Tremorigenic doses of DDT increased the 5-hydroxyindoleacetic acid (5-HIAA) level in hypothalamus, brainstem, and striatum, whereas doses of 75 and 100 mg/kg increased the 3-methoxy-4-hydroxyphenylglycol (MHPG) level in hypothalamus and brainstem and the 3,4-dihydroxyphenylacetic acid level in striatum. Six amino acids were assayed in the brainstem, hypothalamus, and striatum; aspartate and glutamate levels were increased only in brainstem at 25-100 mg/kg. No consistent changes in concentrations of taurine, glutamine, glycine, or gamma-aminobutyric acid were observed in any of the regions assayed. Time-related increases in rectal temperature were seen 2-12 h after dosing, and the presence of tremor was observed 5-12 h after dosing; for both the time of peak effect was at 12 h. The DDT-induced hyperthermia and tremor were associated with dose- and time-related increases in levels of 5-HIAA, MHPG, aspartate, and glutamate. It is suggested that an increase in the turnover rate of 5-hydroxytryptamine (5-HT) may be responsible for the DDT-induced hyperthermia, whereas increases in the metabolism of 5-HT and norepinephrine may be involved in the tremor.     

The complete amino-acid sequence of the proteinase inhibitor B from the root of the arrowhead (Sagittaria sagittifolia L.)

After reduction and alkylation of the disulfide bonds of the proteinase inhibitor B from the root of the arrowhead (Sagittaria sagittifolia L.) followed by CNBr cleavage three peptide fragments with 68, 62 and 11 amino-acid residues could be separated on DEAE-Sepharose CL-6B. The peptides or the inhibitor itself were further specifically cleaved either by trypsin or by the mixture of (CH3)2SO/HCl/HBr at the arginyl- and the tryptophyl-peptide bond, respectively. The complete amino-acid sequences of the peptides were determined by manual solid phase DABITC/PITC double coupling micro-method and the primary structure of the arrowhead inhibitor B consisting of 141 amino-acid residues was then elucidated. Twenty pairs of amino-acid residues are repeated in the molecule of this inhibitor, three of these pairs even occur three times. The possible locations of the reactive sites are discussed. On the basis of sequence comparisons between this inhibitor and all other serine proteinase inhibitors the arrowhead inhibitor may belong to a new family.     

湖北贝母的染色体核型分析

本文报道了我国特有植物湖北贝母(Fritillaria hupehensis Hsiao et K.C.Hsia,百合科)的体细胞染色体数目和核型(2n=24=2m+2sin+4st+14t+2st~(sat).)     

甲型流感病毒自然温度敏感株的宿主依赖性

用鸡胚细胞(CEC)和Madin-Darby Canine Kidney(MDCK)两个宿主细胞系统,检查甲型流感病毒各亚型不同时期流行株的温度敏感性状(ts),发现自然界存在许多宿主依赖的温度敏感性突变株(hd-ts)。它们在CEC上是ts,在MDCK上却是ts~ 。检出的hd-ts株中有些曾经过人体接种观察证明为减毒株。这表明在CEC中鉴定的ts表型与对人减毒性状密切相关。     

贵州部分森林群落物种多样性初步研究

 本文根据贵州省178个森林群落样地的数据研究了群落物种的多样性。测定的指标有群 落物种丰富度,群落Simpson多样性指数和群落均匀度。测定结果表明;不同垂直带生物气 候条件下的森林群落有不同的多样性。相同垂直带生物气候条件下,基质生境相同时,不同森林植被亚型的群落的多样性近似,基质生境不同时,群落多样性则不同;同一群落类型的各个样地的多样性也有变化,结构不同的群落个体,其多样性指数不同,演替趋势也不同。乔木第二亚层的多样性普遍地高于乔木第一亚层。同一演替系列中,越接近顶极阶段多样性越高。多样性指数与群落物种丰富度,均匀度呈紧密的正相关,与群落个体总数没有相关。认为多样性测定在比较、说明群落的结构、类型、组织特征、生境、演替等方面有一定意义。