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毛白杨树皮内含物对光肩星天牛抗性的探讨 总被引:18,自引:3,他引:18
毛白杨树皮内含物对光肩星天牛抗性的探讨王蕤,巨关升,秦锡祥(中国林业科学研究院林业研究所北京100091)关键词杨树,抗性,酚酸,酚甙光启星天牛(AnoplophoraslabripennisMotsh.)对杨树危害严重,受害的树种多,涉及的地域广,... 相似文献
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Hill NS Thompson FN Stuedemann JA Rottinghaus GW Ju HJ Dawe DL Hiatt EE 《Journal of animal science》2001,79(2):542-549
Ergot alkaloids cause fescue toxicosis when livestock graze endophyte-infected tall fescue. It is generally accepted that ergovaline is the toxic component of endophyte-infected tall fescue, but there is no direct evidence to support this hypothesis. The objective of this study was to examine relative and potential transport of ergoline and ergopeptine alkaloids across isolated gastric tissues in vitro. Sheep ruminal and omasal tissues were surgically removed and placed in parabiotic chambers. Equimolar concentrations of lysergic acid, lysergol, ergonovine, ergotamine, and ergocryptine were added to a Kreb's Ringer phosphate (KRP) solution on the mucosal side of the tissue. Tissue was incubated in near-physiological conditions for 240 min. Samples were taken from KRP on the serosal side of the chambers at times 0, 30, 60, 120, 180, and 240 min and analyzed for ergot alkaloids by competitive ELISA. The serosal KRP remaining after incubation was freeze-dried and the alkaloid species quantified by HPLC. The area of ruminal and omasal tissues was measured and the potential transportable alkaloids calculated by multiplying the moles of transported alkaloids per square centimeter of each tissue type by the surface area of the tissue. Studies were conducted to compare alkaloid transport in reticular, ruminal, and omasal tissues and to determine whether transport was active or passive. Ruminal tissue had greater ergot alkaloid transport potential than omasal tissue (85 vs 60 mmol) because of a larger surface area. The ruminal posterior dorsal sac had the greatest potential for alkaloid transport, but the other ruminal tissues were not different from one another. Alkaloid transport was less among reticular tissues than among ruminal tissues. Transport of alkaloids seemed to be an active process. The alkaloids with greatest transport potential were lysergic acid and lysergol. Ergopeptine alkaloids tended to pass across omasal tissues in greater quantities than across ruminal tissues, but their transport was minimal compared to lysergic acid and lysergol. 相似文献
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WU Quan XIAO Xiang-qian LIU Shu-ye LIU Yu SHI Jian-dang WANG Ke-ming ZHANG Ju 《园艺学报》2007,23(7):1382-1387
AIM: To characterize the effect of estradiol on proliferation, differentiation and extracellular matrix (ECM) accumulation in stromal cells through regulation of BPH-1 paracrine. METHODS: BPH-1 cells were stimulated with different concentrations of estradiol. Conditioned media (CM) were harvested and their effects on stromal cell cultures were tested. Cell proliferation was determined by MTT assay. mRNA of smoothelin, fibronectin, collagen Ⅳ and transforming growth factor β1(TGF-β1) were analyzed by real-time RT-PCR. Western blotting was used to determine smooth muscle myosin heavy chain (SMMHC). ELISA and radioimmunoassay were respectively used to measure fibronectin, TGF-β1 and collagen Ⅳ protein expressions.RESULTS: Estrodiol stimulated the expression and secretion of TGF-β1 in BPH-1 cells. The proliferation of stromal cells increased when they were cultured with CM harvested from estrogen treated BPH-1 cells. The mRNA levels of collagen Ⅳ and smoothelin increased in stromal cells treated with CM from BPH-1 cells. The results of radioimmunoassay also showed that the collagen Ⅳ protein level up-regulated in the supernatants and cell extracts of CM-treated stromal cells. A neutralizing antibody to TGF-β1 inhibited the stimulation of collagen Ⅳ and SMMHC by BPH-1 CM. The expression of fibronectin was only marginally changed in stromal cells cultured in the presence of BPH-1 CM. CONCLUSION: The BPH-1 cells increase ECM accumulation and differentiation of stromal cells through TGF-β1. Estradiol stimulate differentiation of stromal cells by induction of TGF-β1 expression. Estradiol stimulate proliferation by influencing the factors secreted from prostatic epithelial cells. 相似文献
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【研究目的】综述了气候变化对东北地区的影响,以期在区域发展中能利用气候变化的有利方面,降低其不利的影响;【方法】根据近年来发表的相关论文,文章综述了东北地区已经发生的气候变化影响及未来可能受到的影响;【结果】结果表明,过去100年东北地区的温度升高明显且降水普遍减少,干旱化趋势严峻。温度的升高改善了东北的热量资源,部分农业生产从中受益。但由于气候变化,目前特殊的生态系统如湿地,冻土退化或消失。未来的气候变化,会改变农业生产布局,降低主要作物的产量,生态系统结构发生改变,农牧带沙漠化的风险增加;【结论】东北地区必须客观认识气候变化的利弊影响,采取相应的适应和应对措施,促进区域发展。 相似文献