天名精倍半萜内酯化合物

从菊科天名精全草中分得天名精内酯酮,特勒内酯,11（13）－二氢特勒内酯和异埃瓦内酯。其中11（13）－二氢特勒内酯和异埃瓦内酯为新的天然产物。     

用核酸斑点杂交法比较油桐尺蠖核型多角体病毒与某些昆虫杆状病毒的同源性

有关核型多角体病毒基因同源性的研究报道不多,结果也不甚一致。目前,国内外普遍用SDS-PAGE法分析昆虫杆状病毒结构多肽,以限制性内切酶谱法测定基因组大小,借此区分来自不同宿主的病毒株,和基因组密切相关     

不同科属来源的六株Frankia代表菌株碳源利用谱的研究

对来自赤杨属、木麻黄属、异木麻黄属、沙棘属和杨梅属的六株Frankia代表菌株进行了二十四种碳源利用谱的比较研究(包括简单有机酸、单糖、双糖、三糖和糖醇在内)。结果表明,各菌株在碳源利用种类和程度上有明显差异;简单有机酸盐特别是丙酸钠是所有菌株的良好碳源;菌株Cc01、A11I1和Hr16还能很好地利用丙酮酸钠;除了菌株Hr16能很好地利用纤维二糖,菌株A11I1利用葡萄糖外;糖醇类很少被利用。如果以丙酮酸钠、丙酸钠和乙酸为“诊断性”碳源,则可以将供试菌株分为三个类群,即赤杨——杨梅类群、沙棘类群和木麻黄类群;这与交叉接种和血清学方法得出的结论相吻合。     

Anti-GM3-lactam monoclonal antibodies of the IgG type recognize natural GM3-ganglioside lactone but not GM3-ganglioside

Immunization of mice with a synthetic GM₃-lactam-BSA (bovine serum albumin) conjugate (designed to emulate the corresponding natural GM₃-lactone conjugate), followed by fusion of splenocytes with myeloma cells, gave rise to more than 300 monoclonal hybridomas producing antibodies to GM₃-lactam-BSA, which did not react with Glc-BSA and BSA. Eight antibody clones were randomly chosen from the positive 300 hybridomas. The eight clones, all belonging to the IgG class, were unreactive against GM₃-ganglioside, whereas two antibodies (P5-1 and P5-3, both IgG₁, ) reacted with GM₃-ganglioside lactone. Binding of these two antibodies to the GM₃-lactam-BSA conjugate was inhibited by soluble glycosides of GM₂-, GM₃-, and GM₄-lactam and by GM₃- and GM₄-lactam, respectively, but not by Gb₃ or asialo-GM₁ and GM₂-saccharides. A third antibody (P3; IgG_2b, ) was inhibited by GM₂-, GM₃-, and GM₄-lactam, but did not recognize GM₃-ganglioside lactone.     

去甲肾上腺素在大鼠缰核引起的心血管效应及其机制

在乌拉坦麻醉的大鼠,研究了去甲肾上腺素(NE)在缰核(Hb)引起的心血管效应及其机制。Hb内微量注射NE使平均动脉压和心率呈剂量依赖性增加。用α受体阻断剂酚妥拉明预处理Hb,可明显减弱NE在Hb引起的心血管效应,但β受体阻断剂心得安或生理盐水不引起任何影响。Hb内微量注射海人酸使平均动脉压和心率明显增加,但Hb内微量注射利多卡因则不能引起明显的心血管效应。上述结果表明,Hb内NE在调节心血管活动中起重要作用,而这种效应可能是通过激活α受体使Hb兴奋的结果。     

NO—样松驰因子在大鼠止血带休克中的作用

为探讨NO-样松驰因子(NO-LRF)在休克中的效应及其病理生理意义,本工作在大鼠止血带休克(ToS)模型上发现离体灌流的主动脉环对去甲肾上腺素的反应性降低,组织cGMP含量增加。用NO前体L-精氨酸(L-Arg)或NO合成阻断剂L-NNA,可溶性乌苷酸环化酶抑制剂亚甲蓝灌流,分别增强或减轻ToS动物主动脉的上述变化,而且这些药物的作用不受血管内皮是否存在的影响。实验结果提示非内皮细胞源的NO-LRF是引起ToS动物血管低反应性的因素之一。体内实验表明 L-Arg治疗缓解,而L-NNA恶化ToS病程,提示NO-LRF可能参与机体的适应保护机制。     

囟土白蚁蚁后卵巢管数量、蚁巢体积与蚁群中各蚁型数量的相关性

囟土白蚁Odontotermes fontanellus Kemner是安徽为害林木、水库堤坝的主要蚁种.研究结果表明:1.在一定的巢龄范围内,随着蚁后身体增长,卵巢管数量增多,一侧的卵巢管最多可达3726条.2.蚁后体长与工蚁数、兵蚁数、幼蚁数、整巢蚁数之间成幂函数关系.3.卵巢管数与蚁后体长、工蚁数、兵蚁数、幼蚁数、整巢蚁数之间成幂函数关系,4,蚁巢体积(y)与蚁后体长(X₂)、兵蚁数(X₄)、的关系式为:y=6.687e^0.0566X₂+0.6741X₄     

两种品系油菜植株成分与蚜虫种群消长及成蚜翅型的关系

本文研究两种品系油菜植株成分与桃蚜(Myzus persicae(Sulzer))、萝卜蚜(Lipaphis erysimi(Kaltenbach))的种群消长及成蚜翅型的关系.经分析得出如下结果:1.桃蚜种群消长与苏氨酸、赖氨酸、组氨酸、丙氨酸、硬脂酸等含量有关;桃蚜成蚜无翅率与精氨酸、谷氨酸、酪氨酸、异亮氨酸等含量有关.2.萝卜蚜种群消长与苏氨酸、蛋氨酸、异亮氨酸、苯丙氨酸、酪氨酸、含水量有关;萝卜蚜成蚜无翅率与含水量.亚麻酸.苏氨酸、油酸,天门冬氨酸、丝氯酸、亚油酸等含量有关.     

Microfilaments in the preprophase band of freeze substituted tobacco root cells

Summary The organization and distribution of microfilaments (MFs) in the preprophase bands (PPBs) of tobacco (Nicotiana tabacum L. var. Maryland Mammoth) root tip cells were studied with high pressure freezing and freeze-substitution methods. MFs were present predominantly as single filaments interspersed among microtubules (MTs) throughout the PPB. Some MFs appeared to be associated with MTs, whereas others were not. This is the first time that MFs have been demonstrated in the PPB at the electron microscope level.     

Spatial and temporal localization of FGF receptors in Xenopus laevis

Summary Mesoderm formation is a result of cell-cell interactions between the vegetal and animal hemisphere and is thought to be mediated by inducing peptide growth factors including members of the FGF and TGF superfamilies. Our immunochemical study analyses the distribution of FGF receptors coded by the human flg gene during embryogenesis of Xenopus laevis. Immunostaining was detected in the dorsal and ventral ectoderm and also in the marginal zone of early cleavage, blastula and gastrula stages. Signals were very strong in the mid and late blastula (stage 8 and 9) and declined slightly in the early gastrula (stage 10). A dramatic decrease was observed up to the late gastrula (stage 11⁺). In stage 13 embryos, immunostaining was only found in cells around the blastopore. Isolated ectoderm cultured in vitro showed a similar temporal expression and decrease of the signal as the normal embryos. These results indicate that receptor expression is independent of the interaction of the animal cells with the vegetal part of the embryo. Of interest is the fact that the signal cannot only be found at or near the cell surface but also within the cell. This suggests the presence of an intracellular isoform of the receptor resulting from the endogenous expression of splice variants and the internalization of transmembrane receptor. Taken together our results suggest that the loss of competence (for bFGF around stage 10) is not directly correlated with the presence of receptors. The possible roles of heparan sulphate glucosaminoglycans (low affinity receptors) and control mechanisms in the intracellular signalling pathway downstream of the receptor level should be taken into consideration.