急性缺氧下听觉运动反应的研究

受试者为9名男性青年。在低压舱模拟海拔3000、4000、5000和6000m,分别进行1h实验,共36人次。各高度上停留时作听觉检测,并记录了脑电和主诉。结果表明,在3000m,人的听觉运动反应基本正常;而在5000m、6000m,听觉运动反应的正确率、延时率、遗漏率和反应时等多项指标发生显著变化,工效降低。本研究为急性缺氧防护生理标准和缺氧耐力提供了工效的依据。     

固氮酶铁钼辅因子FeMo-co在水与非水体系内重组活力与催化活力的比较研究

 本文提出一种测定FeMo-co催化活力的反应体系,用此反应体系,在测定FeMo-co催化活力的过程中,FeMo-co与变种UW45抽提液的重组活性始终保持不变。讨论了水含量、还原剂对FeMo-co催化活力和重组活力的影响。     

不同底物与固氮酶及其钼铁蛋白相互作用的荧光光谱分析

 本文研究了不同底物(N_2,H_2,N_2O,NaN_3,C_2H_2)对棕色固氮菌固氮酶及其钼铁蛋白荧光光谱的影响。结果表明,上述底物均能络合在钼铁蛋白及固氮酶上,但络合程度不同,从而为固氮酶系统有多个不同的底物络合中心,底物络合中心在钼铁蛋白分子上,铁蛋白对钼铁蛋白有变构作用,提供了光谱学证据。     

Ethanol Inhibits Basic Fibroblast Growth Factor-Mediated Proliferation of C6 Astrocytoma Cells

Abstract: Early ethanol exposure alters the proliferative activity of glial and neuronal precursors in the developing CNS. The present study tests the hypothesis that ethanol-induced alterations in cell proliferation result from interference with growth factors. An in vitro model of astroglia (C6 astrocytoma cells) was used to study the effects of ethanol on proliferation mediated by basic fibroblast growth factor (bFGF). bFGF stimulated the proliferation of C6 cells. This bFGF-enhanced proliferation was evident by increases in total cell number, DNA synthesis (as measured by [³H]thymidine incorporation), and the number of cells that took up bromodeoxyuridine. A synthetic peptide that specifically blocked the binding of bFGF to its high-affinity receptor completely abolished the proliferation-promoting effect of bFGF. The action of another mitogen for C6 cells, insulin-like growth factor-1, was not affected by this peptide. Therefore, the bFGF-stimulated proliferation was mediated through a specific bFGF receptor. Ethanol inhibited bFGF-mediated proliferation in a concentration-dependent manner. Ethanol concentrations of 100 and 200 mg/dl partially inhibited bFGF-mediated proliferation (by 58 and 74%, respectively), whereas concentrations of ≥400 mg/dl completely abolished the growth-stimulating effect of bFGF. Our data show that ethanol alters proliferative activity of C6 cells by disrupting the action of bFGF. The target of ethanol neurotoxicity is a receptor-mediated activity. bFGF can affect cell proliferation by a non-receptor-mediated intracellular pathway, but ethanol does not have an impact on this pathway.     

The association of Nef with a cellular serine/threonine kinase and its enhancement of infectivity are viral isolate dependent.

The nef genes of human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV) encode a 27- to 34-kDa myristoylated protein which induces downregulation of CD4 surface levels and enhances virus infectivity. In adult macaques, Nef has been implicated in pathogenesis and disease progression. Both HIV-1 SF2 Nef and SIVmac239 Nef have been shown to associate with a cellular serine/threonine kinase. We tested five functional Nef isolates to examine whether this kinase association is a property conserved among different isolates. HIV-1 SF2 and 248 and SIVmac239 Nef proteins were found associated with the kinase. HIV-1 NL4-3 and 233 Nef proteins were found weakly associated or not associated with the kinase. All five Nef isolates efficiently downregulated CD4 cell surface expression, suggesting that the association with this cellular kinase is not required for Nef to downregulate CD4. Comparison of the SF2 and NL4-3 isolates shows a differential ability of Nef to enhance infectivity that suggests a possible correlation between kinase association and enhancement of infectivity.     

Analysis of the serotype-specific epitopes of avian infectious bronchitis virus strains Ark99 and Mass41.

The Ark and Mass serotype-specific epitopes of infectious bronchitis virus were studied by immunofluorescence and immunoprecipitation of mutant and recombinant spike glycoproteins (S protein) expressed in mouse L cells. Serotype-specific monoclonal antibodies could bind to the recombinant proteins of Ark99 and Mass41 expressed from the chimeras in which the N-terminal thirds of the S1 sequences were reciprocally exchanged. Therefore, it appears that the respective serotype-specific epitopes of both strains were localized within the C-terminal two-thirds of the S1 proteins. Deletion and insertion of a five-amino-acid fragment on the S1 proteins of Ark99 and Mass41, altered the serotype-specific epitopes. This result implies that the five-amino-acid insertion on the S1 protein of the Ark serotype was involved in determining the conformation of the protein, probably acting as a spacer. In addition, it appears that an interaction between sequences of the N-terminal third and the remaining portion of the S1 protein determines the tertiary structure of the protein as well as the conformation of the serotype-specific epitope.     

新疆贝母属的订正

本文根据所收集到的标本和有关文献资料,对新疆贝母属进行了整理。归并9种和21变种。确认新疆贝母属有7种,包括一新分布种,裕民贝母F．stenanthera。     

黄皮种子发育过程中脱水敏感性与细胞膜透性的关系

黄皮（Ｃｌａｕｓｅｎａ ｌａｎｓｉｕｍ （Ｌｏｕｒ．） Ｓｋｅｅｌｓ）胚轴与完整种子的发育模式以及发育中电解质渗漏率变化有些不同． 种子生理成熟前、后的胚轴对脱水的反应也不同,前者经轻微脱水可提高萌发率和活力指数,后者不耐任何程度的脱水．活力指数的急剧下降伴随着电解质渗漏率的迅速上升．实验表明,黄皮种子在发育过程中没有形成耐脱水性． 细胞膜透性变化可反映脱水对种子的伤害程度