小鼠精母细胞联会复合体RNA组分的电镜研究

本文运用常规染色和Bernhard染色方法对切片标本中小鼠粗线期精母细胞联会复合体(SC)的超微结构和电镜细胞化学特点进行了研究。经常规染色后,可见SC由侧生组分(LE)、中央组分(CE)和L-C纤维组成;SC宽约210nm,LE宽约60nm,中央间隔区宽约90nm。在Bernhard染色标本中,SC的LE、CE和L-C纤维着色较深,说明其中含有RNA;SC各结构组分的宽度和形态特点与常规染色标本中的基本一致。本文讨论了SC中存在有RNA等问题。     

云南10个民族红细胞酸性磷酸酶型分布调查

用淀粉凝胶电泳法对云南省汉族及9个少数民族的红细胞酸性磷酸酶(ACP_1)的表型分布进行了调查,检出A、BA和B3种表型,计算得云南汉、彝、白、傣、瑶、佤、哈尼、布朗、基诺和拉祜族ACP_1~A、ACP_1~B的基因频率依次为0.2067、0.7933;0.2406、0.7594;0.2341、0.7659;0.3750、0.6250;0.2300、0.7700;0.2727、0.7273;0.3594、0.6406;0.3036、0.6964;0.2381、0.76119和0.4474、0.5526。未发现ACP_1~C基因及其它稀有基因。研究表明,ACP_1表型的分布存在着一定的种族与民族差异。     

高胆固醇高脂肪膳食对家兔β-VLDL组成及其与巨噬细胞相互作用的影响的初步研究

给家兔喂以1％胆固醇及10％菜油(A组)或猪油(B组)50多天后A组血胆固醇水平(824.2±265.1mg/dl)明显低于B组(1666±693.8mg/dl);A组甘油三酯水平(51.9±19.1mg/dl)亦低于B组(104±40.2mg/dl)。二组家兔的β—VLDL的脂类组成无差别,但A组β—VLDL的apoE高于B组,分别为45.2％及37.5％。高分子量apoB(apoB_h)为33.6％,低于B组β-VLDL(47.3％)。A组β-VLDL促进小鼠腹腔巨噬细胞胆固醇堆积的程度大于B组,可能与apoE含量高有关。我们认为多不饱和脂酸减轻动脉粥样硬化(As)的作用不在于改变脂蛋白构成后阻碍泡沫细胞的形成而是促进β—VLDL从体内清除。     

CD4-independent, productive human immunodeficiency virus type 1 infection of hepatoma cell lines in vitro.

Five hepatoma cell lines, including CZHC/8571, PLC/PRF/5, Hep3B, HepG2, and HUH7, were inoculated with three diverse isolates of human immunodeficiency virus type 1 (HIV-1). Productive infection was noted in all hepatoma cell lines, and expression of viral p24 antigen lasted for over 3 months, but its level decreased in proportion to the number of viable cells. HIV-1 antigens were also found in the cells by immunohistochemical staining and radioimmunoprecipitation assay, as were viral RNA by in situ hybridization and HIV-1-like particles by electron microscopy. Virus yield assays were also positive on supernatant fluids collected from hepatoma cultures inoculated with HIV-1. Despite their susceptibility to infection, all five hepatoma cell lines were negative for CD4 by immunofluorescence and for CD4 mRNA by slot-blot hybridization. In addition, HIV-1 infection of hepatoma cell lines was not blocked by anti-CD4 monoclonal antibody or soluble CD4. Together, these findings clearly demonstrate that all five hepatoma cell lines were susceptible to productive infection by HIV-1 in vitro via a CD4-independent mechanism.     

伤害性刺激和非伤害性刺激对大鼠丘脑后核神经元电活动的影响

用微电极细胞外记录的方法,观察内脏痛、躯体痛和触觉刺激对大鼠丘脑后核(PO)中770个神经元电活动的影响,其中305(38.3％)个对伤害性刺激起反应,103(13.4％)个对触觉刺激起反应。对伤害性刺激反应的神经元中多数对躯体痛和内脏痛刺激均起反应且反应形式相同,少数反应不同或相反,对触觉刺激反应的神经元中多数也对两种伤害性刺激均起反应,只对触觉刺激反应的神经元很少。     

家兔中脑导水管周围灰质中注射八肽胆囊收缩素（CCK—8）拮抗吗啡镇痛和...

We have reported that intracerebroventricular (i. c. v.) injection of 1-4 ng of CCK-8 to the rat produced a remarkable antagonistic effect on morphine analgesia. In order to study the species specificity and the site of action, CCK-8 was microinjected into the PAG of the rabbit, and its influence on morphine analgesia and electroacupuncture analgesia was observed. The latency of the escape response (ERL) to radiant heat focused on the snout was measured as an index of the pain threshold. Microinjections were made via cannulae chronically implanted into the PAG. The drug solutions were delivered in a volume of 1 microliter, at a speed of 0.125 microliter/min. The ERL was measured for a period of 60 or 70 minutes at 10 min intervals. 1. CCK-8 administered unilaterally to the PAG of the rabbit at a dose of 3 ng antagonized the analgesia induced by morphine (4 mg/kg, i. v.) by 73% (P less than 0.001), and reduced the analgesic effect of electroacupuncture by 67% (P less than 0.001). These effects were dose-dependent within the range from 1.5 ng to 6.0 ng. The effect of CCK-8 was reversed by CCK receptor blocker proglumide (4 microliters, intra-PAG injection). Unsulfated CCK-8 (CCK-us) had no effect in this regard. These results indicate that in the PAG of the rabbit, exogenously administered CCK-8 was capable of antagonizing opioid analgesia by the activation of CCK receptors. 2. Two groups of rabbits were given with morphine (2 mg/kg, i. v.) and simultaneous injection of CCK-8 antiserum (CCK-AS, 1 microliter) or normal rabbit serum (NRS) into the PAG.(ABSTRACT TRUNCATED AT 250 WORDS)     

Control of Continuous Irradiation Injury on Potatoes with Daily Temperature Cycling

Two controlled-environment experiments were conducted to determine the effects of temperature fluctuations under continuous irradiation on growth and tuberization of two potato (Solanum tuberosum L.) cultivars, Kennebec and Superior. These cultivars had exhibited chlorotic and stunted growth under continuous irradiation and constant temperatures. The plants were grown for 4 weeks in the first experiment and for 6 weeks in the second experiment. Each experiment was conducted under continuous irradiation of 400 micromoles per square meter per second of photosynthetic photon flux and included two temperature treatments: constant 18°C and fluctuating 22°C/14°C on a 12-hour cycle. A common vapor pressure deficit of 0.62 kilopascal was maintained at all temperatures. Plants under constant 18°C were stunted and had chlorotic and abscised leaves and essentially no tuber formation. Plants grown under the fluctuating temperature treatment developed normally, were developing tubers, and had a fivefold or greater total dry weight as compared with those under the constant temperature. These results suggest that a thermoperiod can allow normal plant growth and tuberization in potato cultivars that are unable to develop effectively under continuous irradiation.     

Lysophosphatidate Acyltransferase in the Microsomes from Maturing Seeds of Meadowfoam (Limnanthes alba)

Lysophosphatidate (LPA) acyltransferase (EC 2.3. 1.51) in the microsomes from the maturing seeds of meadowfoam (Limnanthes alba), nasturtium (Tropaeolum majus), palm (Syagrus cocoides), castor bean (Ricinus communis), soybean (Glycine max), maize (Zea mays), and rapeseed (Brassica napus) were tested for their specificities toward 1-oleoyl-LPA or 1-erucoyl-LPA, and oleoyl coenzyme A (CoA) or erucoyl CoA. All the enzymes could use either of the two acyl acceptors and oleoyl CoA, but only the meadowfoam enzyme could use erucoyl CoA as the acyl donor to produce dierucoyl phosphatidic acid (PA). The meadowfoam enzyme was studied further. It had an optimal activity at pH 7 to 8, and its activity was inhibited by 1 millimolar MnCl₂, ZnCl₂, or p-chloromercuribenzoate. In a test of substrate specificity using increasing concentrations of either 1-oleoyl-LPA or 1-erucoyl-LPA, and either oleoyl CoA or erucoyl CoA, the enzyme activity in producing PA was highest for dioleoyl-PA, followed successively by 1-oleoyl-2-erucoyl-PA, dierucoyl-PA, and 1-erucoyl-2-oleoyl-PA. In a test of substrate selectivity using a fixed combined concentration, but varying proportions, of 1-oleoyl-LPA and 1-erucoyl-LPA, and of oleoyl CoA and erucoyl CoA, the enzyme showed a pattern of acyl preference similar to that observed in the test of substrate specificity, but the preference toward oleoyl moiety in the substrates was slightly stronger. The meadowfoam microsomes could convert [¹⁴C]glycerol-3-phosphate to diacylglycerols and triacylglycerols in the presence of erucoyl CoA. The meadowfoam LPA acyltransferase is unique in its ability to produce dierucoyl-PA, and should be a prime candidate for use in the production of trierucin oils in rapeseed via genetic engineering.