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.     

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.     

酪氨酸对大鼠子宫胞浆雌,孕激素受体的影响

采用放射受体分析法,测定了动情周期不同阶段及去卵巢大鼠子宫胞浆雌二醇和孕酮受体含量,并观察了子宫腔内注射酪、丝、苏三种氨基酸对子宫胞浆雌。醇、孕酮受体含量的影响。结果表明：（１）Ｌ－酪氨酸对动情前期、动情期、间情期大鼠子宫胞浆雌二醇和孕酮受体都具有明显的降低作用。（２）Ｌ－酪氨酸也降低去卵巢大鼠子宫胞浆雌二醇和孕酮含量,即这一作用不是通过影响卵巢激素分泌实现的。（３）Ｌ－苏氨酸仅可降低动情期和间情期大鼠子宫胞浆孕酮受体含量,而对相应周期雌二醇受体没有明显作用。（４）Ｌ－丝氨酸和Ｌ－苏氨酸对去卵巢大鼠子宫胞浆雌二醇和孕酮受体均无影响。     

电刺激大鼠外侧缰核对延髓甩尾相关细胞的活动和甩尾反射的影响

在浅麻醉大鼠上,在延髓腹内侧结构内观察到三种具有不同放电类型的细胞,即乃尾前放电骤停的撤反应细胞,甩尾前放电骤增的给反应细胞和甩尾无关的中性细胞。电刺激外侧缰核可抑制撤反应细胞的自发放电,加强给反应细胞自发放电,从而易化两类细胞的甩尾相关反应,同时易化伤害刺激引起的甩尾反射。实验结果说明,外侧缰核对节段性防御反射有易化作用,这种易化作用可能是通过延髓内撤反应和反应细胞的协同活动而实现的。     

热暴露大鼠心肌细胞钙稳态及其调节机制的研究

本文观察了离体成年大鼠心室肌肌质网、线粒体Ｃａ＾２＋－ＡＴＰ酶活性和总钙含是到及原代培养乳腺心肌细胞＾４６Ｃａ摄取、活性钙调素相对含量、胞浆内游离钙浓度在不同温度热暴露４０ｍｉｎ后的变化。结果表明：热暴露后,心肌奖浆、肌质网及线粒体中的Ｃａ＾２＋－ＡＴＰ酶活发表 所下降,心肌肌质网及线粒体中的总钙含量亦有降低趋势,心肌细胞活性钙调素相对含量显著下降,＾４６Ｃａ摄取量及胞浆内游离浓度显著升高。提示,     

迷走神经背核的研究进展

迷走神经背核（ＤＭＶ）是一个重要的内脏运动核团和内脏感觉核团。ＤＭＶ与中枢及外周存在广泛的纤维联系。ＤＭＶ和孤束核、最后区一起构成了“迷走感觉运动中枢”。ＤＭＶ存在神经－体液回路,使ＤＭＶ神经元可以直接感受外周血及脑脊液中的信息。ＤＭＶ含乙酰胆碱、儿茶酚胺、神经肽类等多种递质及相应受体。ＤＭＶ参与中枢调节胃肠、心血管及内分泌等生理功能。     

CO2／盐冲击对小麦幼苗呼吸酶活性的影响

以不同抗盐小麦 (Triticum aestivum L.)为材料 ,研究了 CO2 /盐冲击对幼苗生长状况、叶绿素含量、光呼吸和三羧酸循环 (TCAC)关键酶活性的影响。结果表明 :Na Cl抑制小麦生长 ,而 CO2 促进生长 ,这种效应盐处理植株比非盐处理植株明显 ;Na Cl降低叶绿素含量 ,CO2 可使其轻微提高 ;盐对普通小麦TCAC中的异柠檬酸脱氢酶 (IDH)、琥珀酸脱氢酶 (SDH)、苹果酸脱氢酶 (MDH)和光呼吸中的乙醇酸氧化酶 (GO)、羟基丙酮酸还原酶 (HPR)有刺激作用 ,CO2 则抑制它们的活性。抗盐小麦对 CO2 /盐冲击的反应与普通小麦有差别。结果可以说明 ,CO2 能够减轻 Na Cl对植物的毒害效应     

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     

棕色固氮菌缺失nifZ基因的突变种固氮酶MoFe蛋白的纯化和性质

采用 52℃下加热 6 min,后经 DEAE- 52、Sephacryls S- 2 0 0和 Q- Sepharose等柱层析方法 ,分离纯化了棕色固氮菌 (Azotobacter vinelandii)缺失 nif Z基因突变种固氮酶 Mo Fe(Δnif Z Mo Fe)蛋白 ,其纯度达到电泳纯。Δnif Z Mo Fe蛋白的固氮活性为 2 83nmol C2 H2 还原 / (min·mg蛋白 ) ,远低于野生种 Mo Fe蛋白。Δnif Z Mo Fe蛋白对氧更敏感 ;热稳定性略低于野生种。Δnif Z Mo Fe蛋白的可见光吸收光谱与野生种 Mo Fe蛋白极为相似。其圆二色谱和磁圆二色谱在 450～ 550 nm与野生种 Mo Fe蛋白显著不同 ,表明其 P- cluster及其周围环境与野生种 Mo Fe蛋白有所差异。这亦可能是造成缺失 nif Z突变种 Mo Fe蛋白固氮活性低的原因。     

SRY盒基因在斑马鱼和胡子鲇中的保守性分析

本文采用人类SRY基因探针,与EcoRI消化的中国的胡子鲇(Clarias fusc us)和美国的斑马鱼(Brachydanio rerio)基因组DNA进行了Southern印迹杂交分析。首次在这两种鱼中发现了SRY盒基因及其存在特征;在斑马鱼中发现了明显的限制性片段长度多态性; 并深入分析了SRY盒基因的进化保守性。 Abstract:Using,Southern bloting analysis,EcoRI-digested genomic DNA from Clarias fuscus and Brachydanio rerio were hybridizae to human SRY probe.Hybridization occurred in both male and female of the two species.RFLP associated with SRY-box genes was observed in Brachydanio rerio.The conservation of SRY-box genes was analysed.