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21.
取食雄蜂蛹粉对龟纹瓢虫和异色瓢虫卵黄发生的影响 总被引:1,自引:1,他引:0
本文比较了龟纹瓢虫Proylea japonica和异色瓢虫Harmonia axyridis取食蚜虫和取食雄蜂蛹粉时的卵黄发生情况.当取食雄蜂蛹粉时,体内卵黄蛋白出现迟,积累速度慢,产卵前期长.但用保幼激素类似物ZR512点滴处理后则能达到与食蚜对照相当的水平.ZR512对取食雄蜂蛹粉瓢虫的作用显著大于取食岈虫者.进一步的研究表明,ZR512能促进这两种瓢虫取食雄蜂蛹粉,但对成虫的体重没有明显的影响.因此推论,雄蜂蛹粉基本能够满足这两种瓢虫生殖的营养需要,但对其内分泌有一定的影响,使瓢虫处于类似生殖滞育的状态.本文根据不同食物条件对卵黄蛋白发生的影响不同,建议用卵黄蛋白的量作为生理指标,以快速初步筛选和评估人工饲料. 相似文献
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本文记述采自云南澜沧江水系的鲤科(鱼丹)亚科鱼类一新属新种。新属裸(鱼丹)属Gymnodanio gen.nov.在侧线、臀鳍条数目等特征上近似于低线(?)属Barilius,但以其除侧线鳞外体裸露无鳞,具不完全之腹棱等而与其及(鱼丹)亚科现有各属相区别。新种命名为条纹裸(鱼丹)G.strigatus sp.nov.。 相似文献
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三节茧蜂属Acampsis Wesmael是屏腹茧蜂亚科中的1个小属,全世界仅知1种。本文新添在我国发现的2个新种:中华三节茧蜂A.chinensis sp.nov.(陕西)和湖南三节茧蜂A.hunanensis sp.nov.(湖南)。这是本属在我国的首次发现,也是在东洋区的首次报道。 相似文献
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The influence of human T lymphocytes expressing the enzyme dipeptidyl peptidase IV (DPP IV) was investigated with respect to human peripheral B-lymphocyte differentiation. B cells stimulated with pokeweed mitogen in the presence of DPP IV-positive T cells produced high amounts of immunoglobulin. Moderate amounts of immunoglobulin could be measured when B cells were cultured in the presence of DPP IV-negative T cells. DPP IV defines a T-cell subset partially overlapping the subsets characterized by the differentiation antigens Leu 3a (helper/inducer) and Leu 2a (suppressor/cytotoxic). DPP IV-positive T cells exert, in contrast to DPP IV-negative T cells, high interleukin-2 activity after stimulation with phytohemagglutinin and pokeweed mitogen. To further functionally characterize DPP IV-positive and DPP IV-negative T cells, the helper effects of Leu 3a-positive T-cell subsets, differing in DPP IV expression, were investigated in pokeweed mitogen- and Staphylococcus aureus-driven B-cell differentiation systems. After pokeweed mitogen stimulation, immunoglobulin production was markedly reduced when B cells were cultured in the presence of Leu 3a-positive T cells expressing DPP IV (DPP IV+/Leu 3a+). In contrast, high amounts of immunoglobulin were produced in cultures with Leu 3a-positive but DPP IV-negative T cells (DPP IV-/Leu 3a+). This difference in immunoglobulin production of B cells cultured with DPP IV+/Leu 3a+ and DPP IV-/Leu 3a+ T cells could not be observed in Staphylococcus aureus-stimulated cultures. Here, both T-cell subsets supported terminal differentiation of B cells. We conclude that in the pokeweed mitogen-driven culture systems, DPP IV+/Leu 3a+ and DPP IV-/Leu 3a+ T cells may differ in the production of growth and/or differentiation factors distinct from interleukin-2. 相似文献
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Rapid and reversible modulation of T4 (CD4) on monocytoid cells by phorbol myristate acetate: effect on HIV susceptibility 总被引:4,自引:0,他引:4
The effect of phorbol myristate acetate (PMA) on T4 (CD4) expression by monocytoid cells was studied. Greater than 99% of untreated U937 and HL-60 cells expressed surface T4 as measured with a fluorescence-activated cell sorter. The percentage of T4 positive cells decreased to less than 20% after incubation with PMA (10(-8) M). A decrease was observed within 15 min of PMA exposure, was maximal within 1 hr, and persisted for at least 3 days in the continuous presence of PMA. The susceptibility of untreated and PMA-treated U937 cells to human immunodeficiency virus (HIV) was also studied. Pretreatment of cells with PMA for 18 hr decreased the production of viral RNA and p24 antigen 24 hr after infection. The dose of PMA resulted in a parallel reduction of both T4 expression and infection by HIV. When PMA was washed from cultures and replaced with fresh medium for 48 hr, then T4 expression and the production viral RNA and p24 antigen following infection were restored. These data suggest that pharmacologic manipulation of surface T4 expression may have a potential role in the prevention or treatment of HIV infection. 相似文献
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实验在33只浅麻醉、肌肉麻痹、人工呼吸及切断双侧颈迷走神经的家兔上进行。观察中缝大核区电解损毁或微量注射利多卡因对呼吸活动及臂旁内侧核区微量注射吗啡所致呼吸抑制效应的影响。结果是:电解损毀中缝大核区,使呼吸频率增加,膈神经放电的幅度和频率均无明显变化,而臂旁内侧核区微量注射吗啡抑制呼吸的程度减轻;中缝大核区微量注射利多卡因,则部分消除臂旁内侧核区微量注射吗啡的呼吸抑制效应。中缝大核旁网状结构电解损毁或微量注射利多卡因,不影响吗啡的呼吸抑制效应。上述结果提示,中缝大核区可能在脑桥臂旁内侧核区微量注射吗啡抑制呼吸的机制中起一定作用。 相似文献