力竭游泳对大鼠心肌线粒体钙运输的影响

 力竭游泳对大鼠心肌线粒体钙运输的影响丁树哲,王文信,连克杰,许豪文（华东师范大学体育系运动生化实验室,上海２０００６２）线粒体钙运输在细胞功能调节方面有重要作用．线粒体通过摄取与释放钙,对其跨膜质子、不依赖底物及产物抑制的ＡＴＰ合成、磷酸化偶联等均有...     

兼具SOD和GPX活力的双功能酶的制备及性质研究

用苯甲基磺酰氟（ＰＭＳＦ）和Ｈ_２Ｓｅ相继处理铜锌超氧化物岐化酶（Ｃｕ,Ｚｎ－ＳＯＤ）,将酶分子中的丝氨酸（Ｓｅｒ）转化为硒代半胱氨酸（ＳｅＣｙｓ）,从而引入了谷胱甘肽过氧化物酶（ＧＰＸ）的催化基团,使其在ＳＯＤ酶活性大部分保留的情况下,具有ＧＰＸ活性,其ＧＰＸ活力是ＰＺ５１活力的３０倍。研究了双功能酶的最佳制备条件,包括ＰＭＳＦ的剂量、反应最适温度及Ｈ_２Ｓｅ处理时间等,并用电子能谱、ＤＴＮＢ等方法测定了双功能酶的硒含量;测定了双功能酶对不同底物的米氏常数及双功能酶的荧光光谱、紫外吸收光谱及稳定性。     

Effect of physostigmine on relative acetylcholine output induced by systemic treatment with scopolamine in in vivo microdialysis of rat frontal cortex

By means of an in vivo brain microdialysis, the effect of different concentrations of physostigmine on the acetylcholine level in the dialysate of rat frontal cortex was studied. Perfusion of the various degrees of physostigmine (eserine) concentration (10 nM−10 μM) into the cortex through the dialysis membrane increased the basal acetylcholine level in a dose-dependent manner. In the presence of 10 nM, 0.1 μM and 10 μM physostigmine in the perfusate, systemic treatment with scopolamine (0.5 mg/kg, i.p.) increased 200, 270 and 510%, respectively, the relative acetylcholine level in the dialysates in comparison with the corresponding basal levels, while in the absence of physostigmine the treatment increased it only 40%. From these results, it appears that perfusion of physostigmine at a variety of concentrations, changes not only the basal level of acetylcholine induced by the inhibition of acetylcholinesterase but also the relative acetylcholine output induced by systemic treatment with scopolamine.     

简便、快速提取高质量的RNA分子

MethodsforHandy,RapidIsolationofHighQualityRNAbyGuanadiumThioeyauateDuJianYuanYanhuaMaShenglinDongZhiwei(BeijingInstituteforCancerResearchBeijing100034)硫氰胍是一种有效的蛋白变性剂。早在1979年,Chirgwin等就利用氯化铯／硫氰胍超离心技术成功地从RNA酶富集的胰脏组织中提取出未降解的RNA分子[2],从而使它成为抑制RNA酶的首选药物并得到广泛使用,但受到超速离心设备的限制。1983年,Cathala报道了氯化锂／硫氰胍RNA提取法[1]。该方法操作简便,获得的RNA质量很高,但所需时间较长。为了能在短时间内更快…     

Chronic Nicotine Administration Differentially Affects Neurotransmitter Release from Rat Striatal Slices

Abstract: The objective of these experiments was to determine whether the chronic administration of nicotine, at a dose regimen that increases the density of nicotine binding sites, alters the nicotine-induced release of [³H]dopamine ([³H]DA), [³H]norepinephrine ([³H]NE), [³H]serotonin ([³H]5-HT), or [³H]acetylcholine ([³H]ACh) from rat striatal slices. For these experiments, rats received subcutaneous injections of either saline or nicotine bitartrate [1.76 mg (3.6 µmol)/kg, dissolved in saline] twice daily for 10 days, and neurotransmitter release was measured following preloading of the tissues with [³H]DA, [³H]NE, [³H]5-HT, or [³H]choline. Chronic nicotine administration did not affect the accumulation of tritium by striatal slices, the basal release of radioactivity, or the 25 mM KCl-evoked release of neurotransmitter. Superfusion of striatal slices with 1, 10, and 100 µM nicotine increased [³H]DA release in a concentration-dependent manner, and release from slices from nicotine-injected animals was significantly (p < 0.05) greater than release from saline-injected controls; release from the former increased to 132, 191, and 172% of release from the controls following superfusion with 1, 10, and 100 µM nicotine, respectively. Similarly, [³H]5-HT release increased in a concentration-related manner following superfusion with nicotine, and release from slices from nicotine-injected rats was significantly (p < 0.05) greater than that from controls. [³H]5-HT release from slices from nicotine-injected rats evoked by superfusion with 1 and 10 µM nicotine increased to 453 and 217%, respectively, of release from slices from saline-injected animals. The nicotine-induced release of [³H]NE from striatal slices was also concentration dependent but was unaffected by chronic nicotine administration. [³H]ACh release from striatal slices could not be detected when samples were superfused with nicotine but was measurable when tissues were incubated with nicotine. The release of [³H]ACh from slices from nicotine-injected rats was significantly (p < 0.05) less than release from controls and decreased to 36, 83, and 77% of control values following incubation with 1, 10, or 100 µM nicotine, respectively. This decreased [³H]ACh release could not be attributed to methodological differences because slices from nicotine-injected rats incubated with nicotine exhibited an increased [³H]DA release, similar to results from superfusion studies. In addition, it is unlikely that the decreased release of [³H]ACh from striatal slices from nicotine-injected rats was secondary to increased DA release because [³H]ACh release from slices from hippocampus, which is not tonically inhibited by DA, also decreased significantly (p < 0.05) in response to nicotine; hippocampal slices from nicotine-injected rats incubated with 1 and 10 µM nicotine decreased to 42 and 70%, respectively, of release from slices from saline-injected animals. Results indicate that the chronic administration of nicotine increases the ability of nicotine to induce the release of [³H]DA and [³H]5-HT and decreases the ability of nicotine to evoke the release of [³H]ACh but does not alter the nicotine-induced release of [³H]NE from brain slices.     

Extractive fermentation of lactic acid by immobilizedLactobacillus casei using ion—exchange resin

Summary A novel method of lactic acid fermentation byLactobacillus casei immobilized in Ca—alginate gels is described, in which an ion—exchange resin packed column is attached to a fermentor for separation of lactic acid from fermentative broth. The technique successfully alleviated the restriction imposed by lactic acid on bacterial growth and product formation. As compared to the conventional batch fermentation, the new fermentation technique enhanced the lactic acid productivity and sugar conversion rate from 0.328g/L·h and 88. 2% to 0.482g/L·h and 98.6%, respectively.     

基因工程链激酶(r—SK)纯化及其单克隆抗体制备和鉴定

采用Rotofor等电聚焦和分子筛技术纯化大肠杆菌表达的重组链激酶(r—SK),其纯度为97%。比活性1×10⁶IU／mg,回收率41％。分析所纯化的r—SK　N端氨基酸顺序证实其1—15个氨基酸顺序与SK基因的核苷酸顺序所示3联密码子一致。以纯化r—SK为抗原,通过杂交瘤技术构建了分泌抗r—SK单克隆抗体(McAb)杂交瘤细胞(4D11),该McAb属IgG1亚型．特异地作用于r-SK和C组口溶血性链球菌分泌的SK。用底物显色法测定该McAb可抑制SK对纤溶酶原的激活。Western blot法证实该McAb能识别分子量为16 250Da的r—SK的CNBr裂解片段。推测SK蛋白中第71残基至第237残基间的氨基酸顺序参与SK与纤溶酶原的结合。     

抗人PAI—1单克隆抗体制备,鉴定和应用

以重组PAI-(rPAI-1)为抗原,通过杂交瘤技术获得6株阳性杂交瘤细胞(AP1、AP2、AP3、AP4、AP5和AP6),并用SPA亲和层析纯化了抗PAI-1单克隆抗体(McAb)。所有McAb均能识别rPAI和天然PAI-1,腹水滴度均为10~6以上。6种McAb对PAI-1亲和常数在3.45×10~7—1.05×10~9mol/L之间。AP2、AP3 McAb能完全抑制PAI-1活性,AP4、AP和AP6只能部分抑制PAI-1活性,AP1则不抑制PAI-1活性。6种McAb中只有AP1、AP4和AP5能识别PAI-1/t-PA复合物。利用AP1、AP3、和AP4 McAb制备免疫亲和柱一步纯化HepG_2细胞分泌的PAI-1,纯度大于98％,回收率92％,纯化倍数51倍。利用抗PAI-1 McAb建立了夹心法ELISA,测定了人血浆PAI-1水平,正常人血浆PAI-1平均含量(±D)为24.7±7.75ng/ml。     

碳源对固定化细胞生产柠檬酸的影响

柠檬酸是利用微生物代谢生产的一种极为重要的有机酸．广泛应用于食品、饮料、化工、冶金、印染等各个领域。在国外,近10年来,利用固定化细胞生产柠檬酸已获得较广泛的研究^〔1－6〕,国内也有学者指出,柠檬酸发酵的趋向是利用固定化细胞进行连续化生产⑺。而国内这方面的研究报道很少〔8,9〕。我们利用海藻酸钙凝胶包埋固定化黑曲霉细胞生产柠檬酸．探讨了碳源种类及其浓度对固定化细胞生产柠檬酸的影响。现将结果报道如下。     

甘薯象空间格局及抽样技术研究

通过空间分布型指数分析,甘薯象对薯块、著株危害空间分布型为随机分布或均匀分布;同时确定了理论抽样数