Exercise: effects on hexokinase activity in red and white skeletal muscle

Single bouts of exercise increase hexokinase activity in red and white skeletal muscle of guinea pigs. Multiple bouts of exercise cause two-fold increases. In contrast to other enzymes associated with glycolysis, hexokinase activity is higher in red than in white skeletal muscle.     

Elevation of aortic proline hydroxylase: a biochemical defect in experimental arteriosclerosis

The relation of collagen synthesis to experimentally induced arteriosclerosis was studied by measuring proline hydroxylase activity. Gross aortic plaques were produced in rabbits by daily injection of epinephrine (intravenous) and thyroxine (intraperitoneal) for 4, 9, or 14 days. Activity of proline hydroxylase was significantly increased after 4 days of treatment and reached a peak, five- to sixfold increase, after 14 days of treatment. The increase in enzyme activity was correlated with the severity of observed arteriosclerosis. Increase in proline hydroxylase activity may be a possible biochemical defect in the aortas of rabbits with arteriosclerosis induced by injury.     

Benzpyrene hydroxylase induction by polycyclic hydrocarbons in hamster embryonic cells grown in vitro

Treatment of hamster embryonic cells with 1,2-benzanthracene for 4 to 48 hours induced a three- to tenfold increase in the activity of benzpyrene hydroxylase. That the increase in enzyme activity was completely prevented by puromycin suggested an induction of enzyme synthesis.     

蜂胶中4种黄酮对HepG2细胞胰岛素抵抗的改善作用

为探究蜂胶中4种黄酮成分(高良姜素、短叶松素、松属素、柯因)对胰岛素抵抗的改善作用。通过高浓度胰岛素诱导的方式建立胰岛素抵抗HepG2细胞模型;设立正常组、模型组、高良姜素处理组、短叶松素处理组、松属素处理组、柯因处理组,测定各试验组对HepG2细胞增殖、葡萄糖消耗量、糖原含量、已糖激酶(hexokinase,HK)和丙酮酸激酶(pyruvate kinase,PK)的影响。结果显示:4种黄酮成分在有效浓度范围内对胰岛素抵抗HepG2细胞增殖均无显著影响(P0.05);柯因、短叶松素作用效果不明显(P0.05);高良姜素和松属素均能不同程度地提高IR-HepG2细胞葡萄糖消耗量(glucose consumption,GC)、肝糖原含量、HK和PK活力(P0.05)。上述结果表明蜂胶中高良姜素和松属素能较好地调节IR-HepG2糖代谢,改善胰岛素抵抗,为蜂胶产品的深度开发提供参考。     

蜂胶对体外培养的血管内皮细胞增殖活力的影响

本试验旨在研究蜂胶对体外培养的血管内皮细胞增殖活力的影响。试验以体外培养的血管内皮细胞作为模型,用100μmol／L过氧化氢诱导血管内皮细胞损伤后,以四甲基偶氮唑蓝比色法检测细胞增殖活力,BudR渗入法检测细胞DNA合成。结果表明质量浓度为4mg／L的蜂胶可促进正常血管内皮细胞增殖（P〈0．01）,可明显抑制过氧化氢诱导的血管内皮细胞的损伤（P〈0．01）。     

Carcinogens 3,4-benzpyrene and 3-methylcholanthrene: induction of mitochondrial oxidative enzymes

Sections of liver from rats injected with 3,4-benzpyrene and 3-methylcholanthrene, when incubated in mediums specific for the histochemical demonstration of mitochondrial oxidative enzymes, show greater activity of several of these enzymes than do sections from control rats. This observation was confirmed by comparison of the staining of mitochondria isolated from the control and from "induced" rats. The fact that an inhibitor of protein synthesis, actinomycin D, effectively diminished the stimulation provided evidence that the stimulation of activity is due to an increase in enzyme synthesis, generally called induction.     

Pyrimidine nucleotide synthesis: regulatory control during transformation of lymphocytes in vitro

The incorporation of uridine into RNA in lymphocytes undergoing transformation induced by phytohemagglutinin parallels its incorporation into the intratcellular pool of acid-soluble nucleotides and coincides with a 20-fold increase in the specific activity of uridine kinase. This increase is dependent upon synthesis of both RNA and protein and is subject to both repression and end-product inhibition by cytidine.     

Hexokinase isoenzymes in human erythrocytes

The electrophoretic mobility of hexokinase from human erythrocytes and other tissues was studied with a new method that depends on the fluorescence of reduced nicotinamide-adenine dinucleotide phosphate for detecting enzyme activity on starch gel. The hexokinase of cord-blood erythrocytes has slightly different electrophoretic properties from that of adult red cells. Type I enzyme is split into type I(A) and type I(F); the latter is more intense in cord blood; in hemolyzates of adult blood, the activity of the two bands is usually about equal. No type II enzyme was found in cord blood. The double type I band was present in red cells from adult rabbits.     

UV-C对葡萄果实发育过程中黄烷醇类多酚积累及隐色花色素还原酶表达的影响

【目的】阐明葡萄果实发育过程中,植株接受UV-C照射对果实中黄烷醇类多酚积累的作用。【方法】以5年生赤霞珠葡萄为试材,定期对植株进行UV-C照射,分别采用分光光度计法、Western Blot和Real time PCR法对黄烷醇类多酚积累及其生物合成关键酶LAR表达进行分析,从底物、酶活性、蛋白质含量及基因转录水平阐明UV-C对Vv lar1、lar2基因表达的影响。【结果】葡萄果实发育过程中,UV-C照射并未改变果实中黄烷醇类多酚的积累规律,但诱导黄烷醇类多酚积累,特别是在幼果期,UV-C照射明显诱导果实中黄烷醇类多酚的积累。UV-C照射诱导葡萄果实LAR酶活性升高,LAR1、LAR2蛋白含量增加,Vv lar1、Vv lar2转录增强。【结论】UV-C能够诱导Vv lar1、Vv lar2转录,合成新LAR1、LAR2蛋白,LAR酶活性增强,导致黄烷醇类多酚在葡萄果实中积累。     

Estrogen-receptor interaction

The interaction of estradiol with uterine cells involves the association of the hormone with an extranuclear receptor protein, followed by temperature dependent translocation of the resulting complex to the nucleus. During this process, the steroid binding unit of the protein undergoes an alteration, called "receptor transformation," that can be recognized by an increase in its sedimentation rate from 3.8S to 5.2S, and by its acquisition of the ability to bind to isolated uterine nuclei and to alleviate a tissue specific deficiency in the RNA synthesizing capacity of such nuclei. Receptor transformation can be effected in the absence of nuclei by warming uterine cytosol with estradiol. This preparation of transformed complex resembles that extracted from nuclei both in its sedimentation rate (5.3S) and in its ability to bind to uterine nuclei and augment RNA synthesis, properties that are not shown by the native complex. It is proposed that receptor transformation is an important step in estrogen action and that a principal role of the hormone is to induce conversion of the receptor protein to a biochemically functional form.     

啤酒废酵母制备的富铬酵母对糖尿病小鼠糖代谢的影响

[目的]研究富铬酵母对糖尿病小鼠糖代谢的影响。[方法]利用富集铬元素的啤酒废酵母制备富铬酵母,检测其基本营养指标。通过建立糖尿病小鼠模型考察富铬酵母对糖尿病小鼠的作用和有效剂量,给药试验4周后,检测血糖值、己糖激酶和苹果酸脱氢酶活性。[结果]富铬酵母的蛋白质含量为44.7%,铬含量为810.4±14.3 mg/kg,其中有机铬含量占85%以上。富铬酵母剂量在中剂量（150 mg/kg）时可显示显著的降糖能力,在高剂量时降糖能力更为显著。糖尿病小鼠在补充富铬酵母后,小鼠体内己糖激酶和苹果酸脱氢酶活力均有提高,且酶活力的增加随富铬酵母的添加量的增加而增加。[结论]在试验范围内,小鼠体内苹果酸脱氢酶活力与对照组还有较大差异,而高剂量组富铬酵母己糖激酶活力已与正常对照无显著差异。     

Cyclic adenosine monophosphate: andromimetic action on seminal vesicular enzymes

Administration of adenosine 3',5'-monophosphate with theophylline produced testosterone-like induction of hexokinase, phosphofructokinase, pyruvate kinase, and glucose-6-phosphate dehydrogenase in the seminal vesicles of both orchidectomized and immature rats. The N(6)-O(2)'-dibutyryl analog of this cyclic nucleotide produced greater increases in vesicular enzyme activities than those induced by the parent compound. The observed enhancement of the key glycolytic enzymes and of hexose monophosphate shunt dehydrogenase was significantly inhibited by actinomycin D and cycloheximide. The evidence indicates that cyclic adenosine monophosphate may be involved as an intermediary in the action of androgenic hormones on male accessory sex organs.     

Regenerating fish optic nerves and a regeneration-like response in injured optic nerves of adult rabbits

Regeneration of fish optic nerve (representing regenerative central nervous system) was accompanied by increased activity of regeneration-triggering factors produced by nonneuronal cells. A graft of regenerating fish optic nerve, or a "wrap-around" implant containing medium conditioned by it, induced a response associated with regeneration in injured optic nerves of adult rabbits (representing a nonregenerative central nervous system). This response was manifested by an increase of general protein synthesis and of selective polypeptides in the retinas and by the ability of the retina to sprout in culture.     

Dopamine synthesis: stimulation by a hypothalamic factor

The effect of treatment with the factor that inhibits the release of melanocyte stimulating hormone (MSH) identified as 1-prolyl-1-leucylglycinamide (MIF) on brain catecholamine synthesis was examined in normal and hypophysectomized rats. The tripeptide induced a dose-related increase in striatal dopamine synthesis in slices obtained from treated normal animals but not in hypophysectomized animals. Hypothalamic norepinephrine synthesis was unaltered by MIF treatment in normal as well as in hypophysectomized rats. In addition, dopamine and norepinephrine syntheses were depressed in untreated hypophysectomized animals, as compared to normal controls. These results constitute the first direct demonstration of a central neurochemical effect of a hypothalamic factor.     

Induction of ovalbumin synthesis in immature chicks by actinomycin D and thioacetamide

Actinomycin D and thioacetamide induced ovalbumin synthesis and increased serum progesterone concentrations in immature chicks. The increase in progesterone induced by the carcinogens actinomycin D and thioacetamide may account for the induction of ovalbumin synthesis.     

荔枝果皮花青苷合成与相关酶的关系研究

以‘妃子笑’荔枝为试材,研究果实成熟过程中,果皮中花青苷含量及其生物合成相关的苯丙氨酸解氨酶(PAL)、查儿酮异构酶(CHI)、二氢黄酮醇还原酶(DFR)和类黄酮糖基转移酶(UFGT)的酶活性变化,同时研究套袋和生长调节剂对花青苷合成和相关酶活性的影响。结果表明,在4种酶中只有UFGT活性与荔枝果皮花青苷合成关系密切。UFGT活性的变化与花青苷含量的变化趋势吻合;随着‘妃子笑’果皮中UFGT活性的增加,花青苷含量上升;套袋处理抑制UFGT活性的同时也抑制花青苷的合成,除袋后UFGT活性和花青苷含量都迅速增加;6-BA处理抑制UFGT酶活性的同时也抑制花青苷合成,ABA和茉莉酸处理提高了UFGT酶活性的同时也促进了花青苷的合成。     

2,3,7,8-Tetrachlorodibenzo-p-dioxin: a potent inducer of -aminolevulinic acid synthetase

2,3,7,8-Tetrachlorodibenzo-p-dioxin, a toxic contaminant frequently formed during the synthesis of the herbicide 2,4,5-trichlorophenoxyacetic acid, was shown to be a potent inducer of hepatic delta-aminolevulinic acid synthetase in the chick embryo. As little as 4.66 x 10(-12) mole of the contaminant per egg produces a significant increase in the activity of the enzyme. Induction of the enzyme is related to the dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin and, in contrast to that produced with other drugs, is prolonged in time, with 70 percent of the maximum induced activity present 5 days after a single dose. This contaminant is implicated as the likely causative agent in an outbreak of porphyria cutanea tarda in workers in a factory where 2,4,5-trichlorophenoxyacetic acid was being synthesized.     

端粒酶活性在子宫颈癌组织中的表达

目的 :了解不同临床分期、组织学分级子宫颈鳞癌组织中端粒酶活性。方法 :采用以 PCR为基础的端粒酶重复扩增方法及非变性 PAGE银染定性法检测不同临床分期、组织学分级子宫颈鳞癌组织中端粒酶活性。结果 :在子宫颈癌组织中端粒酶活性的表达率较正常宫颈、不典型增生宫颈组织的端粒酶活性高 (P<0 .0 1 ) ,且不同临床分期的子宫颈癌宫颈组织间端粒酶的表达率差异有显著性 (P〈0 .0 5) ,但不同病理分级的子宫颈癌宫颈组织间端粒酶活性的表达率差异无显著性 (P>0 .0 5)。结论 :端粒酶在子宫颈癌组织中呈现高表达 ,且与临床分期有关 ,端粒酶可望成为检测子宫颈癌的一个重要指标。     

Leaf Responses of Micropropagated Apple Plants to Water Stress： Changes in Endogenous Hormones and Their Influence on Carbohydrate Metabolism

The changes in the concentrations of endogenous hormones and their influence on carbohydrate metabolism in leaves of micropropagated Fuji apple plants were studied under water deficiency stress. The results showed that water stress induced a rapid increase in the concentration of abscisic acid （ABA） and led to a decrease in concentrations of both zeatin and gibberellins （GAs）. The concentration of indole-3-acetic acid （IAA） changed in an independent manner, which was not correlated with the different levels of water stress. With regard to the carbohydrates, the contents of sorbitol and sucrose increased, whereas the content of starch decreased. The increase in the concentration of ABA was significantly correlated with both the increase in the activity of aldose-6-phosphate reductase （A6PR） and the decrease in the activity of sorbitol dehydrogenase （SDH）, indicating that ABA played a regulatory role in sorbitol metabolism. The concentration of ABA was positively correlated to the activity of sucrose-phosphate synthase （SPS） but negatively correlated to the activities of acid invertase （AI） and ADP-glucose-pyrophosphorylase （ADPGppase） in water-stressed plants, which indicated that ABA promoted sucrose synthesis and inhibited sucrose degradation and starch synthesis at the same time. Under conditions of water stress, the decrease in the level of zeatin was accompanied by a decrease in the activities of SDH and ADPGPPase. GAs concentration showed positive correlation with ADPGPPase activity. IAA showed no significant correlation with any of the enzymes tested in this study. The results of this study suggested that ABA might be one of the key factors regulating the distribution of carbohydrates under water stress. The metabolism of sorbitol and starch under conditions of water stress might be regulated by the combined action of many plant hormones.     

接种丛枝菌根真菌对棉花生长和黄萎病的影响

研究了接种两种丛枝菌根真菌(Glomus mosseae和Glomus etunicatum)对棉花生长和对黄萎病的影响,并且探讨了丛枝菌根真菌诱导植物抗病性的可能机制.结果表明,接种丛枝菌根真菌后能促进棉花的营养生长,增加叶绿素的含量,促进光合作用的进行;在先接种丛枝菌根真菌然后接种黄萎病原菌的情况下,可以增加棉花根内总酚含量,诱导棉花根内过氧化物酶(POD)的合成,提高POD的活性,明显降低棉花黄萎病的发病率和发病指数.另一方面,当黄萎病原菌侵袭时,丛枝菌根真菌对根的侵染率降低,说明两者之间存在着一定的相互关系.丛枝菌根的形成对于棉花植株产生了多方面的影响,而丛枝菌根真菌诱导植物抗病性的机理是一个关于植物组织结构和生理生化发生变化的复杂过程,与改善植物营养、与病原物竞争光合产物和侵染位点、激活植物防御机制等方面相关.