ESR检测大鼠肺巨噬细胞释放的活性氧自由基

用ESR捕捉技术检测大鼠AM释放的活性氧自由基的性质表明:1.PMA和BCG均能刺激AM产生较强的OH·;能刺激人末稍血白细胞释放活性氧自由基的ConA和顺铂在本实验条件下未能使AM产生活性氧自由基信号。2.经膜活性剂PMA刺激的AM所释放活性氧自由基的高峰在刺激后2min,而经颗粒性物质BCG刺激,AM释放自由基的高峰时间明显后移。3.测试体系中的AM数过多或过少都不适合捕捉ESR信号。在本实验条件下,捕捉到最高自由基信号的AM终浓度为5×10⁷AM/ml。4.测试体系中存在DETAPAC或EDTA,可使捕捉到的自由基信号明显增强。     

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.     

Regional and Ontogenic Expression of the NMDA Receptor Subunit NR2D Protein in Rat Brain Using a Subunit-Specific Antibody

Abstract: A polyclonal antibody for the NMDA receptor subunit NR2D has been developed that identifies an ∼160-kDa band on immunoblots from NR2D transfected cells and CNS tissues. No cross-reactivity is seen with other NMDA receptor subunits. The NR2D receptor subunit is N -glycosylated in both brain and transfected cells. Transfected cells expressing NR2D are immunofluorescently labeled, whereas untransfected cells or cells transfected with other NMDA receptor subunit cDNAs are not. Similarly, the NR2D subunit is selectively and quantitatively immunoprecipitated, whereas the NR1, NR2A, or NR2B subunit is not. The relative densities of the NR2D subunit in nine areas of postnatal day 7 and adult rat brains have been determined by quantitative immunoblotting. NR2D was expressed at highest levels in the thalamus, midbrain, medulla, and spinal cord, whereas intermediate levels of this subunit were found in the cortex and hippocampus. Low or undetectable levels were seen in the olfactory bulb, striatum, and cerebellum. Following a peak after the first week of birth, NR2D protein levels decreased by about twofold in adulthood in all rat brain regions examined. More complete ontogenic profiles were determined for the diencephalon, telencephalon, and spinal cord where similar ontogenic patterns were seen. NR2D protein is present at high levels at embryonic stages of development, rises to a peak at postnatal day 7, and decreases but remains measurable during late postnatal life. This study demonstrates the generation and characterization of an antibody selective for the NR2D NMDA receptor subunit as well as a determination of the distribution and ontogenic profile of this subunit in rat brain. The results suggest that native NMDA receptors containing the NR2D subunit may have functional roles not only in the young brain but also in adult brain.     

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.     

Characterization of inhibition of M2 ion channel activity by BL-1743, an inhibitor of influenza A virus.

The influenza A virus M2 integral membrane protein has ion channel activity that can be inhibited by the antiviral drug amantadine. Recently, a spirene-containing compound, BL-1743 (2-[3-azaspiro (5,5)undecanol]-2-imidazoline), that inhibits influenza virus growth was identified (S. Kurtz, G. Lao, K. M. Hahnenberger, C. Brooks, O. Gecha, K. Ingalls, K.-I. Numata, and M. Krystal, Antimicrob. Agents Chemother. 39:2204-2209, 1995). We have examined the ability of BL-1743 to inhibit the M2 ion channel when expressed in oocytes of Xenopus laevis. BL-1743 inhibition is complete as far as can be measured by electrophysiological methods and is reversible, with a reverse reaction rate constant of 4.0 x 10(-3) s(-1). In contrast, amantadine inhibition is irreversible within the time frame of the experiment. However, BL-1743 inhibition and amantadine inhibition have similar properties. The majority of isolated influenza viruses resistant to BL-1743 are also amantadine resistant. In addition, all known amino acid changes which result in amantadine resistance also confer BL-1743 resistance. However, one BL-1743-resistant virus isolated, designated M2-I35T, contained the change Ile-35-->Thr. This virus is >70-fold more resistant to BL-1743 and only 10-fold more resistant to amantadine than the wild-type virus. When the ion channel activity of M2-I35T was examined in oocytes, it was found that M2-I35T is BL-1743 resistant but is reversibly inhibited by amantadine. These findings suggest that these two drugs interact differently with the M2 protein transmembrane pore region.     

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。     

菠菜BADH单抗细胞株及其应用初探

用菠菜甜菜碱醛脱氢酶 ( BADH)免疫巴比西 ( BALB/c)小鼠 ,将其脾细胞与骨髓瘤细胞 SP2 /O-Ag1 4融合 ,在 1 92孔中 ,有约 1 4 %孔生长的杂交瘤细胞 ,用间接酶联免疫方法 ( ELISA)检测表现为阳性。选择其中 2 G3和 2 D10 细胞系 ,用有限稀释法进行克隆化培养 ,约 2 0 %克隆化细胞为强阳性。选择其中 2 G3- H3细胞株注射到 BALB/c小鼠腹腔中诱导腹水 ,腹水的单抗效价为 1∶ 1 0 3。应用 BADH单抗检查了大麦、水稻、高粱、小麦幼苗的叶片和根的粗提物 ,均呈阳性反应 ,表明 BADH除在光合组织中存在外 ,在非光合组织中也可能存在。讨论了非光合组织 BADH的意义