巯基修饰对中华仓鼠二氢叶酸还原酶的激活

脊椎动物二氢叶酸还原酶（ＤＨＦＲ,Ｅ．Ｃ．１．５．１．３）可被多种因素激活,如中性无机盐［１］、蛋白质变性剂［１～４］、巯基修饰剂［１,４～７］等．来源于鸡肝［５］、猪肝［６］、鼠肝［７］及鼠Ｌ１２１０细胞［４］二氢叶酸还原酶的巯基修饰激活已有报道．...     

缺氧时大鼠红细胞变形性损伤的机制研究

本实验通过测定平原和模拟高原减压缺氧３０天大鼠红细胞滤过指数（ＩＦ）、红细胞内［ｐＨ］ｉ、［Ｋ＋］ｉ／［Ｎａ＋］ｉ比值、［Ｃａ２＋］ｉ、［Ｍｇ２＋］ｉ、平均红细胞体积（ＭＣＶ）及平均红细胞血红蛋白浓度（ＭＣＨＣ）,从而探讨缺氧条件下大鼠红细胞变形性损害的机制。结果发现：１．缺氧组大鼠红细胞［Ｃａ２＋］ｉ明显升高,且与ＩＦ呈显著正相关,但［Ｍｇ２＋］ｉ无明显差异;２．缺氧组［Ｋ＋］ｉ／［Ｎａ＋］ｉ值较平原组明显降低,且与ＩＦ呈显著负相关;３．缺氧组ＭＣＨＣ与平原组无明显差异,但ＭＣＶ显著升高;４．缺氧组红细胞内［ｐＨ］ｉ较平原组明显升高。提示：缺氧时红细胞［Ｃａ２＋］ｉ升高,［Ｋ＋］ｉ／［Ｎａ＋］ｉ值降低,ＭＣＶ增大以及红细胞［ｐＨ］ｉ值的改变在其变形性损伤中起重要作用。     

ANALYSIS OF GENETIC CORRELATIONS FOR QUALITY TRAITS IN INDICA RICE

INTRODUCTIONTherearesomekindsofcorrelatedrelationshiPsbetweenagronomytraitsIntndtcarice．Geneticandenvlronmentatcorrelat［onshavebeenanalyzedforsometraitsInrice［‘·’J．LiandYangfoundadditivecorrelationcoefficientswerefrom一0．773to0·993forsomeflowertraitsInrice［’］．Yuhavefoundthataddltlvecorrelationwasslgnlflcantforsometraitsinbarley［13］．Uptonow,partitioningthegenotyplccovarlanceoftraitsInricehasnomorethanaddltlveanddominancecovarlancecomponents．kcausethenutrl－＊＊t吕Of凡8…     

GM_3抑制人白血病J6－2细胞肌醇磷脂代谢循环

采用无载体￣（３２）Ｐ和［￣３Ｈ］肌醇标记磷脂,观察了促分化剂神经节苷脂ＧＭ＿３对人单核样白血病Ｊ６－２细胞肌醇磷脂代谢的影响,ＧＭ＿３抑制［￣（３２）Ｐ］Ｐｉ和［￣３Ｈ］肌醇掺入Ｊ６－２细胞磷脂酰肌醇（ＰＩ）,促进［￣（３２）Ｐ］Ｐｉ和［￣３Ｈ］肌醇掺入磷脂酰肌醇－４,５－二磷酸（ＰＩＰ＿２）,抑制［￣（３２）Ｐ］Ｐｉ掺入磷脂酸（ＰＡ）,抑制［￣３Ｈ］肌醇掺入三磷酸肌醇（ＩＰ＿３）．ＧＭ＿３的上述作用均为浓度依赖性的,随ＧＭ＿３浓度的提高而增强．上述结果表明,ＧＭ＿３抑制Ｊ６－２细胞的肌醇磷脂代谢循环．     

表达多聚半乳糖醛酸酶反义RNA的转基因番茄分析

果实成熟是一系列基因在时空上有序表达的结果［１］,成熟阶段出现的多聚半乳糖醛酸酶（ＰＧ,Ｅ,Ｃ,３,２,１,１５）在果实软化过程中起作用［２,３］。番茄果实的软化与ＰＧｍＲＮＡ及ＰＧ活性增加呈平行关系［４］。ＰＧ的表达有发育阶段性［１,５］与组织特异性［６,７］,其调控主要是在转录水平［８,９］。本工作将ＰＧ反义基因转入番茄,对Ｔ０～Ｔ２代转基因果实的ＰＧ活性、生理后熟行为及品质进行了研究。１　材料和方法１．１　ＰＧ反义基因植物表达载体构建及Ｎｏｒｔｈｅｒｎ检测方法见前文［１０］。１．２　转化与…     

［B3－Lys］－胰岛素的研究：受体结合及生物活性

本文用１２５Ｔ－［Ｂ３－Ｌｙｓ］－胰岛素和１２５Ⅰ－胰岛素研究了［Ｂ３－Ｌｙｓ］－胰岛素和胰岛素与人胎盘细胞膜（ＨＰＭ）胰岛素受体结合特性并进行了比较。实验结果表明［Ｂ３－Ｌｙｓ］－胰岛素与ＥＰＭ胰岛素受体结合能力比天然猪胰岛素高。由竞争取代曲线得到的［Ｂ３－Ｌｙｓ］－胰岛素和猪胰岛素的ＩＣ（５０）值分别为０．６５和１．１１ｎｍｏｌ／Ｌ。经Ｓｃａｔｃｈａｒｄ分析得出［Ｂ３－Ｌｙｓ］－胰岛素与ＨＰＭ胰岛素受体中高亲和位点和低亲和位点结合的亲和常数分别为１．７２×１０９和２．２７×１０６Ｌ／ｍｏｌ,而猪胰岛素分别为１．２６×１０９和１．４７×１０６／ｍｏｌ。促脂肪细胞合成脂肪实验结果表明［Ｂ３－Ｌｙｓ］－胰岛素也同样具有比天然猪胰岛素更高的离体生物活力,ＥＣ（５０）分别为０．１７５和０．３０１ｎｍｏｌ／Ｌ。可见［Ｂ３－Ｌｙｓ］－胰岛素的受体结合能力和高体生物活力都为猪胰岛素的１．７倍。     

烟草多酚氧化酶的分离与固定化技术研究

多酚氧化酶属于氧化还原酶类,国际酶学委员会推荐名为儿茶酚氧化酶（ＥＣ１．１０．３．１ｐｏｌｙｐｈｅｎｏｌｏｘｉｄａｓｅ,ＰＰＯ）．该酶与食品工业、三废处理、医药卫生关系较为密切,因而研究较多．如近年来鸭梨［１］、蘑菇［２］、香蕉果肉组织［３］、荔枝果皮［４］等等中的多酚氧化酶均有研究报道．目前研究用固定化多酚氧化酶检测废水中酚类物质含量,进行环境检测;及其从工业废水中除去酚类,达到治理三废的目的．Ｍｏｓｂａｃｎ［５］（１９７６）研制成多酚氧化酶固定化酶柱,与氧电极检测器组合联用,可检测水中２０…     

一类具周期系数的单种群模型及其最优收获策略

文［１］用直接求解的方法,得到了具周期系数的广义Ｌｏｇｉｓｔｉｃ单种群收获模型的最优收获策略．本文在参照并推广文［２］中一类具周期系数的单种群收获模型周期解的全局渐近稳定性结果的基础上,用变分方法得到了其最优收获策略．所得结果包括了许多常见的自治单种群模型所对应的具周期系数的收获模型,如Ｌｏｇｉｓｔｉｃ型［１］,Ｇｉｌｐｉｎ和Ａｙａｌａ型, Ｇｏｍｐｅｒｔｚ型［３］,以及具类似于Ⅱ,Ⅲ类Ｈｏｌｌｉｎｇ型功能性反应的密度制约函数［４,５］的模型等．     

[B3—Lys]—胰岛素的研究：受体结合及生物活性

本文用＾１２５Ｉ－［Ｂ３－Ｌｙｓ］－胰岛素和＾１２５Ｉ－胰岛素研究了［Ｂ３－Ｌｙｓ］－胰岛素和胰岛素与人胎盘细胞膜胰岛素受体结合物性并进行了比较。实验结果表明［Ｂ３－Ｌｙｓ］－胰岛素与ＨＰＭ胰岛素受体结合能力比天然猪胰岛素高。由竞争取代曲线得到的［Ｂ３－Ｌｙｓ］－胰岛素和猪胰岛素的ＩＣ（５０）值分另为０．６５和１．１１ｎｍｏｌ／Ｌ。经Ｓｃａｔｃｈａｒｄ分别得出［Ｂ３－Ｌｙｓ］－胰岛素与ＨＰＭ胰岛素     

豆薯种籽中一种抗真菌蛋白PaAFP的分离纯化和部分特性研究

各类植物由于缺少自身免疫系统的支持,因而必须依赖于其它机制来抵御外来微生物的入侵．其中的一种重要机制就是通过合成体内各类能抑制微生物生长的蛋白质来完成的［１］．已报道从植物中分离出多种不同的抗真菌蛋白．广为研究的是几丁质酶和β－１,３－葡聚糖酶,认为它们在植物对真菌病的抗性中起重要作用［２,３］;核糖体失活蛋白（ＲＩＰｓ）和一类富含半胱氨酸的碱性多肽Ｔｈｉｏｎｉｎｓ也显示有非专一的抗真菌活性［４,５］．但仍有一些蛋白质,体外表现强烈的抗真菌活性,却不属于以上范围［６,７］．本文报道了豆薯种籽中一…     

甲基营养菌WB-1甲胺磷降解酶的产生、部分纯化及性质

甲基营养菌WB１菌株在以甲胺磷作碳氮源的无机盐培养基上生长时,产生甲胺磷降解酶情况较好,培养20 h为细胞收获的适宜时期。所得细胞经过超声波破碎、吐温20抽提、热处理(60℃,9min)\,DEAE\|纤维素32和CM\|纤维素32柱层析等步骤,得到的酶制品比活力为180U/mg,收率78.8%,纯化倍数22.8。纯化的酶制品经连续聚丙烯酰胺凝胶电泳,呈现一条主带,酶活力染色则呈现一条与之对应的活性谱带;该酶催化反应的适宜pH为90,底物专一性不强,Hg²⁺\,Mn²⁺\,Cu²⁺对酶有强烈的抑制作用。部分纯化酶制品在-20℃(0.1mol/L的磷酸盐溶液中)存放5d,酶活力丧失约60%。     

Using Soil Available P and Activities of Soil Dehydrogenase and Phosphatase as Indicators for Biodegradation of Organophosphorus Pesticide Methamidophos and Glyphosate

The heavy use of organophosphorus pesticides in northeastern China strongly affects the ecological functions and the quality of the soil environment. In this work, a 30-day soil incubation experiment was conducted to evaluate the potential of using soil available P and the activities of soil dehydrogenase and acid phosphatase as indicators of the application of methamidophos and glyphosate. Two kinds of unpolluted soils, phaiozem and burozem, were selected as the test soils. The higher application rate of organophosphorus pesticide to the two soils caused more release of PO₄ ^3? which finally entered the soil available P pool, suggesting that soil available P is one of the effective chemical markers for biodegradation of organophosphorus pesticides. Methamidophos exhibited a significant inhibitory effect on the activity of soil dehydrogenase. The extent of enzyme inhibition was almost positively correlated with the insecticide concentration, and the enzyme activity was gradually restored after day 15. However, its effect on soil acid phosphatase activity (stimulation or inhibition) seemed to be indefinite, and varied with the application rate, soil type, and incubation time. In the case of glyphosate, soil acid phosphatase activity was depressed significantly and the depressing extent could be a function of herbicide concentration and incubation time, but soil dehydrogenase activity showed an irregular variation with the herbicide application rate and soil type. In general, dehydrogenase activity was a good biochemical indicator for the biodegradation of methamidophos, but for glyphosate biodegradation the indicator was acid phosphatase activity.     

用染料修饰吐温80液—固萃取体系从猪心肌匀浆液中分离纯化心肌黄酶

用三嗪类染料 Ｃｉｂａｃｒｏｎ Ｂｌｕｅ Ｆ３Ｇ－Ａ修饰的吐温８０,与吐温８０、硫酸被构成液－固萃取体系,从猪心肌匀浆液中分离纯化心肌黄酶。研究了吐温８０染料修饰物在吐温８０相中所占的比例、分相盐浓度、溶液的酸度、匀浆液的加入量等对匀浆液中酶及杂蛋白在两相中分配的影响。在室温条件下,酶选择性地进入吐温８０固相,杂蛋白主要留在盐水相。匀浆液中心肌黄酶的酶活力平均收得率为８１．４％,一步纯化倍数为６．６。降低盐浓度,提高盐水相酸度,能使酶从吐温８０固相反萃到盐水相。     

乙草胺和甲胺磷对农田黑土可培养真菌数量及种群结构的影响

应用传统及PCR-DGGE方法(denaturing gradient gel electrophoresis),分别对不同浓度乙草胺、甲胺磷胁迫下黑土中可培养真菌CFU(colony forming units)、种群丰富度(richness)及种群结构动态变化规律进行了研究.结果表明,在实验室微域条件下,乙草胺对黑土可培养真菌CFU的影响随处理浓度的增加而抑制作用增强,表现出由低浓度(50 mg·kg^-1)时的刺激生长到高浓度(250 mg·kg^-1)时的长期抑制效应;250 mg·kg^-1甲胺磷在8周处理过程中对土壤可培养真菌生长具有显著的刺激效应,使可培养真菌CFU比对照增加10倍,但50和150 mg·kg^-1甲胺磷处理对土壤可培养真菌CFU无显著影响.种群丰富度系数分析结果表明,高、中浓度乙草胺处理可使土壤可培养真菌种群丰富度不可逆地降低.土壤真菌rDNA特异PCR-DGGE聚类分析结果表明,不同浓度乙草胺、甲胺磷处理均不同程度地对土壤可培养真菌的种群组成和结构造成影响,其中甲胺磷尤为显著.     

甲胺磷、乙草胺和铜单一与复合污染对蚯蚓的毒性效应研究

以赤子爱胜蚓(Eisenia foetida)为例,通过滤纸急性毒性试验法研究了东北黑土区普遍存在的3种农用化学品甲胺磷、乙草胺和Cu对蚯蚓的单一与复合毒性效应．单一实验结果表明,三者对蚯蚓均有毒性,它们的毒性顺序为乙草胺＞甲胺磷＞Cu,半致死浓度分别为：0．307、0．708和118．70mg.kg^-1;同时通过观察可知,乙草胺与Cu以皮肤渗入蚯蚓体的毒性效应较甲胺磷明显．复合毒性实验结果表明,低浓度Cu与高浓度Cu对甲胺磷的毒性均有增强作用;低浓度Cu对乙草胺的毒性有削弱作用,但高浓度Cu对乙草胺的毒性有增强作用．可见,三者对土壤生态系统生态安全性和土壤健康质量存在潜在危害,同时这几种污染物的共存进一步加大了潜在危害性,且复合毒性效应与各组浓度组合密切相关．     

甲胺磷诱发母鸡迟发性神经毒性模型

以成年鸡为实验动物,对甲胺磷原药诱发鸡的迟发性神经毒性进行了研究。检测了甲胺磷对鸡脑神经病靶标酯酶（NTE）的体外抑制情况以及急性中毒后期鸡神经组织NTE活性变化。毒性试验发现,甲胺磷对京白母鸡（Gallus domestics）的毒性主要表现为急性中毒,未见有明显的迟发性神经毒性症状。结果表明,本实验未能通过经口及经皮两种染毒途径在母鸡上建立甲胺磷诱发的迟发性神经毒性模型。     

芽胞杆菌BSD-8肌氨酸氧化酶的纯化与性质

对一株从土壤中分离到的芽胞杆菌Bacillus sp.BSD-8菌株所产生的热稳定性较高的肌氨酸氧化酶进行纯化,并对该酶的特性进行了研究。通过硫酸铵分级沉淀、DEAE-纤维素离子交换柱、Toyopearl疏水层析柱和Sephadex G-75分子筛层析,使酶提纯25倍,比活力达到5.3U/mg。研究了纯化后的酶的生化特性,确定了该酶的主要特性:该酶为黄素蛋白,与黄素以非共价键的方式结合,由单一亚基组成,其亚基分子量为51kDa。酶的最适反应温度及pH分别为60℃与8.5。该酶在60℃及pH8.0~10.0条件下稳定。以Lineveaver-Burk作图法求得该酶米氏常数Km值为3.1mmol/L。Ag+、Hg2+、SDS及Tween80对该酶有强抑制作用,而Tween20和Triton X-100对酶活性无影响。该肌氨酸氧化酶在耐热性质上比以前所报道的肌氨酸氧化酶有很大的提高,在酶法肌酐测定应用中有明显的优势。     

甲胺磷和乙酰甲胺磷对萼花臂尾轮虫实验种群动态的影响

应用3天种群增长实验方法,在(25±1)℃、无光照、以3.0×106 cells/mL的斜生栅藻为轮虫的食物等条件下,研究了亚致死浓度(0.01、0.1、1.0、10.0、100.0、1000.0和10000.0 µg/L)的甲胺磷和乙酰甲胺磷对萼花臂尾轮虫实验种群动态的影响。结果显示,甲胺磷和乙酰甲胺磷显著地影响萼花臂尾轮虫的种群增长率、混交雌体数与非混交雌体数的比值和混交率。甲胺磷显著地影响萼花臂尾轮虫种群中的带卵雌体数与不带卵雌体数的比值,但乙酰甲胺磷对其无显著的影响。和对照组相比,浓度为100.0 µg/L 的甲胺磷和浓度为1.0－10,000.0 µg/L 的乙酰甲胺磷均使轮虫种群增长率显著增大,而浓度为1000.0 µg/L和10000.0 µg/L的甲胺磷却使之显著减小;1000.0 µg/L 的甲胺磷使轮虫种群中的带卵雌体数与不带卵雌体数的比值显著上升,0.1 µg/L的甲胺磷和10.0－10000.0 µg/L的乙酰甲胺磷均使轮虫种群中的混交雌体数与非混交雌体数的比值显著上升,0.1µg/L 的甲胺磷和10 µg/L的乙酰甲胺磷均使轮虫的混交率显著增大,10.0－0000.0 µg/L 的乙酰甲胺磷使轮虫休眠卵产量显著提高。上述结果表明,亚致死浓度的甲胺磷和乙酰甲胺磷对萼花臂尾轮虫实验种群动态具有显著的影响。     

Histochemical patterns of lipolytic enzymes of the hepatopancreas of Scylla serrata and their possible relation to eyestalk factor(s)

Of the lipolytic enzymes studied histochemically, lipase (Tween 80 specific enzyme) showed highest activity while non-specific esterases (Tween 60, α-naphthyl acetate, β-naphthyl acetate and 5-bromo-indoxyl acetate esterases) and Tween 20 and Tween 40 esterases exhibited medium and lowest activities respectively. The pattern of distribution of these enzymes was found to be variable among the various elements of the hepatopancreas. Lipase. Tween 20 and Tween 40 esterases were localized at the apical parts of the R-cell, F-cell cytoplasm, the B-cell vacuolar contents and the lumina of the hepatopancreatic acini. Non-specific esterases were primarily present in the cytoplasm of the R-cells, brush border of the tubules and connective tissue. A striking reduction in the lipase activity of the R- and B-cells was apparent 4 hours after the bilateral extirpation of eyestalks. Restoration of activity was observed 48 hours after the operation. On the other hand, a rise in the level of non-specific esterases was conspicuous 4 hours after the eyestalk amputation. This increased enzyme activity was restored to normal 24 hours after the operation. Administration of eyestalk extract into normal and de-stalked animals caused an increase in the lipase activity of the R- and B-cells. Surprisingly, the activity of non-specific esterases also enhanced considerably in the R-cell cytoplasm and connective tissue. The enhanced activity of lipase and non-specific was noted 4 hours after the treatment. From the present findings it appears that the eyestalk hormone(s) are directly involved in regulating the activity of the lipolytic enzymes. The physiological role of the F- and B-cells seems to be secretion and extrusion of lipase respectively. The R-cells and connective tissue appear to be associated with storage and mobilization of lipids.     

Enzymatic dephosphorylation of retinyl monophosphate by rat liver

Rat liver has been shown to contain an enzyme that catalyzes the dephosphorylation of retinyl monophosphate. This activity was extracted with 0.1 M Tris buffer (pH 7.5). Maximum reaction rate was observed at a pH range of 7.0-7.5. It did not require metal ions for activity and was sensitive to fluoride ion. The retinyl monophosphate phosphatase activity was proportional to time and protein and substrate concentration. Triton X-100 (range of 0.05-0.10%) increased the activity 100%, whereas other detergents (Tween 80, cholate, and deoxycholate) did not activate the enzyme. A number of phosphorylated compounds tested as inhibitors of retinyl monophosphatase activity, such as glucose 6-phosphate (20 mM), glycerophosphate (20 mM), phosphatidic acid (8 mM), and dolichyl phosphate (3 mM), did not compete with retinyl monophosphate as substrate. However, at 20 mM concentration, ATP, ADP, 5'-AMP, and pyrophosphate were inhibitors of the enzyme. It is not possible at present to give further details about the specificity of the phosphatase activity. The enzyme described could play a regulatory role in retinol-mediated glycosylations, by altering the endogenous level of retinyl monophosphate.