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181.
Chromosome breakage caused by mutagens in male germ cells can be analyzed by micronucleus induction during meiotic division. This can be followed in vitro by culturing seminiferous tubular segments from stages of the epithelial cycle that contain late pachytene and diakinetic primary spermatocytes. We studied the mutagenic potential of a male contraceptive, gossypol, in this test system using adriamycin (10 ng/ml) as a reference mutagen. A small but significant increase in the frequency of micronuclei was induced with concentrations of 10 and 20 micrograms/ml of gossypol, while cytotoxic effects appeared at concentration of 20 micrograms/ml and were evident at 50 micrograms/ml. Analysis of meiotic micronucleus induction in vitro seems to be a sensitive test system of male germ-cell mutagenesis, but further studies on the possible mutagenic effects of gossypol are needed. 相似文献
182.
Applied anatomy of the anterolateral femoral flap 总被引:13,自引:0,他引:13
D C Xu S Z Zhong J M Kong G Y Wang M Z Liu L S Luo J H Gao 《Plastic and reconstructive surgery》1988,82(2):305-310
A study of the source of the blood supply to the anterolateral femoral flap was carried out on 42 lower limbs of adult cadavers (among them 35 cadavers with injection of red latex and 1 with india ink into the arteries and 6 vascular cast specimens), and the surface locations of the vascular pedicle were detected on 50 healthy adults. It was found that the descending branch of the lateral circumflex femoral vessel was an ideal axial vessel. There are constant perforating branches of the myocutaneous artery or cutaneous branches from the intermuscular space to the anterolateral femoral skin. The area extends about 12 x 30 cm. Within the flap, the anterior branch of the anterolateral cutaneous nerve of the high is located. This flap has been widely used for free transplantation in China since 1983 with satisfactory results. 相似文献
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184.
我国沙漠中部地区主要不同生态类型植物脯氨酸的累积、光合、呼吸和叶绿素含量 总被引:21,自引:0,他引:21
中生植物脯氨酸含量为0.42mg/g.dw, 低于少浆旱生植物(1.73mg/g.dw)。多浆旱生植物脯氨酸含量最高(7.22mg/g.dw),为前两者的17倍和4倍,两类旱生植物在干旱条件下(非灌溉)脯氨酸含量均高于灌水处理。少浆与多浆旱生植物的光合强度(16.74,14.04CO2mg/g.dw.h)差异不大,而中生植物(37.57mg/g.dW.h)略高于多浆旱生植物(4.73CO2Mg/g.dw.h),与中生植物(7.60Co2mg/g.dw.h)接近,光合/呼吸值,少浆,多浆与中生植物分别为2.50,3.09和4.59,说明中生植物的合成明显大于消耗,季节动态中,中生植物显著高于两类旱生植物,叶绿素总量三类植物差异甚微。 相似文献
185.
除虫菊的染色体数目及其核型 总被引:6,自引:0,他引:6
杜冰群;刘启宏;朱翠英 《武汉植物学研究》1988,6(1):95-96
除虫菊(Pyrethrum cinerariifolium Trev.)为菊科小黄菊属多年生宿根草本植物。以花或全草入药。除虫菊的主要有效成分为除虫菊酯和瓜叶除虫菊酯,可用于加工成各种制剂作杀虫剂原料,用以防治日常虫豸(蚊、蝇、虱等)和农业害虫,且对人 相似文献
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188.
Cibacron blue T_3GA与溴化氰活化的Sepharose 4B偶联后,产生一种能有效地分离有机磷水解酶的吸附剂。用0.15mol/L MgCl_2溶液从黄杆菌P3—2细胞抽提出的粗酶液通过柱层析分离,即可得到纯化8倍、酶活性回收率为269.4%的纯酶制品。该酶制品用凝胶电泳测是均一的。 相似文献
189.
红腹锦鸡和白腹锦鸡卵壳的超微结构 总被引:18,自引:2,他引:16
本文报道了锦鸡属——白腹锦鸡和红腹锦鸡卵壳的气孔、外壳膜、锥体层、木栅层的超微结构。并对两者的卵壳进行了比较。 相似文献
190.
Tyr721 regulates specific binding of the CSF-1 receptor kinase insert to PI 3''-kinase SH2 domains: a model for SH2-mediated receptor-target interactions. 总被引:30,自引:8,他引:22
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M Reedijk X Liu P van der Geer K Letwin M D Waterfield T Hunter T Pawson 《The EMBO journal》1992,11(4):1365-1372
Efficient binding of active phosphatidylinositol (PI) 3'-kinase to the autophosphorylated macrophage colony stimulating factor receptor (CSF-1R) requires the noncatalytic kinase insert (KI) region of the receptor. To test whether this region could function independently to bind PI 3'-kinase, the isolated CSF-1R KI was expressed in Escherichia coli, and was inducibly phosphorylated on tyrosine. The tyrosine phosphorylated form of the CSF-1R KI bound PI 3'-kinase in vitro, whereas the unphosphorylated form had no binding activity. The p85 alpha subunit of PI 3'-kinase contains two Src homology (SH)2 domains, which are implicated in the interactions of signalling proteins with activated receptors. Bacterially expressed p85 alpha SH2 domains complexed in vitro with the tyrosine phosphorylated CSF-1R KI. Binding of the CSF-1R KI to PI 3'-kinase activity, and to the p85 alpha SH2 domains, required phosphorylation of Tyr721 within the KI domain, but was independent of phosphorylation at Tyr697 and Tyr706. Tyr721 was also critical for the association of activated CSF-1R with PI 3'-kinase in mammalian cells. Complex formation between the CSF-1R and PI 3'-kinase can therefore be reconstructed in vitro in a specific interaction involving the phosphorylated receptor KI and the SH2 domains of p85 alpha. 相似文献