耐热醋酸棱状芽孢杆菌中具有高的二硫键还原活性组分的提取和…

用ＤＥＡＥ－Ｓｅｐｈａｒｏｓｅ ＣＬ－６Ｂ层析柱从Ｃ．ｔｈｅｒｍｏａｃｅｔｉｃｕｍ细胞提取物中分离出的两个具有相近分子量（７００）的活性组分，在ＭＶ＾＋存在下，对二硫键具有高的催化还原活性。这两组分参与的催化还原反应不以ＮＡＤ（Ｐ）Ｈ为电子供体。在实验条件下，对二硫键的催化还原活性顺序为：ＧＳＳＧ〉硫辛酰胺〉胱氨酸〉胱氨酸〉硫辛酸。活性组分具有较高的反应稳定性和热稳定性。两组分在２６０、３５４和５     

Clostridium thermoaceticum forms methanol from carbon monoxide in the presence of viologen dyes

Whole cells of Clostridium thermoaceticum, crude extracts of such cells as well as the supernatant of 100 000 × g centrifugations catalyse the reduction of carbon monoxide to methanol in the presence of viologens or cobalt sepulchrate. Without such a mediator methanol could not be detected. The reaction shows a marked optimum at pH 5. The incubation of [5-¹⁴C]methyltetrahydrofolate led only to the formation of ¹⁴C-labeled ethanol; the radioactivity in methanol was negligible. The reaction seems to be catalysed by carbon monoxide dehydrogenase.     

Comparative assessment of inorganic pyrophosphate and pyrophosphatase levels of Escherichia coli, Clostridium pasteurianum, and Clostridium thermoaceticum

Abstract Pyrophosphatase (PP_iase) specific activities were much higher in anaerobic cultures of Escherichia coli (0.54 units) than in Clostridium pasteurianum (0.067 units) and Clostridium thermoaceticum (0.017 units) (1 unit = 1 μ mole PP_i hydrolyzed/min per mg cell dry wt.), and were fairly constant throughout the growth of all three organisms. Conversely, intracellular levels of pyrophosphate (PP_i) were very low and constant in E. coli throughout growth (0.3 mM), while those of C. pasteurianum and C. thermoaceticum were higher (1.44 and 0.8 mM, respectively) and peaked sharply during mid log-phase of growth. PP_iase and intracellular PP_i remained relatively constant in E. coli when grown aerobically or anaerobically, and when growth was in medium containing PP_i as the sole source of supplemental phosphorus.     

20#-5菌株代谢产物中抗菌成分的纯化和结构测定

为弄清假单胞菌20#-5菌株代谢产物中的抗菌活性成分物质种类,先通过有机溶剂萃取、硅胶柱层析分离和HPLC C-18柱纯化得到纯品,再利用UV、IR、MS、1H-NMR及13C-NMR等光谱分析,确定其中的两个活性成分为phenazine-1-carboxylic ac id和3-n-heptyl-3-hydroxy-1,2,3,4-tetrahydroqu inoline-2,4-d ione。     

Regioselective Disulfide Solid Phase Synthesis, Chemical Characterization and In Vitro Receptor Binding Activity of Equine Relaxin

In the equine industry, pregnancy loss during the third trimester constitutes a large percentage of fetal and neonatal mortality and represents a major financial loss and time investment for the breeder. Early identification of placental insufficiency would, in some cases, make it possible to sustain the pregnancy through medical intervention. Recent work suggests that relaxin is a valuable clinical tool for diagnosing placental insufficiency and monitoring treatment efficacy in mares. Relaxin is a polypeptide member of the insulin superfamily that consists of a two-chain structure and three disulfide bonds in a disposition identical to that of insulin. It is typically produced in the ovary during pregnancy and has primary roles in maintaining mammalian pregnancy and facilitating the delivery of the young via remodelling of the reproductive tract. The placenta is the primary source of relaxin in the mare during pregnancy. Its primary structure has been determined and shown to be the smallest of the known mammalian relaxins. It consists of a 20 residue A-chain and a 28-residue B-chain. To undertake detailed biophysical and biological characterization of the peptide, its chemical synthesis was undertaken using regioselective disulfide formation methods. The synthetic equine relaxin showed typical α-helical structure under physiological conditions. The peptide was found to bind to the relaxin receptor, LGR7, in vitro, and its binding affinity was found to be higher than that of the “gold standard”, porcine relaxin, and similar to that of the human relaxin-2 (H2 relaxin).     

噬菌蛭弧菌代谢产物活性成分对小鼠免疫功能的影响

目的研究噬菌蛭弧菌代谢产物活性成分对小鼠免疫功能的影响。方法将噬菌蛭弧菌代谢产物的3种有机溶剂（石油醚、三氯甲烷、乙酸乙酯）提取物和提取后的剩余液体分别腹腔注射实验小鼠,分两次注射,共注射0.5 mL,注射后连续饲养28 d,每隔7 d小鼠采血检测离体白细胞吞噬活性（phagocytic activity）、吞噬细胞杀菌活性（bactericidal activity）、超氧化物歧化酶（superoxide dismutase,SOD）活性、血清凝集抗体效价、血红蛋白值和红细胞数的变化,以研究不同提取物对小鼠免疫功能的影响。结果石油醚提取物组和三氯甲烷提取物组小鼠血清SOD活性、血清凝集抗体效价、离体白细胞吞噬活性和吞噬细胞杀菌活性增强与对照组相比差异极显著（P〈0.01）;乙酸乙酯提取物组SOD活性和血清凝集抗体效价增强与对照组相比差异极显著（P〈0.01）,离体白细胞吞噬活性和吞噬细胞杀菌活性增强与对照组相比差异显著（P〈0.05）;石油醚提取物组的血红蛋白值（12.64 g/100 mL）和红细胞数（11.32×106/mL）最高。各项指标的峰值均出现在第7天~第21天。结论噬菌蛭弧菌代谢产物3种有机溶剂提取的活性物质具有增强小鼠免疫功能的作用。     

Differential induction of genes related to solvent formation during the shift from acidogenesis to solventogenesis in continuous culture of Clostridium acetobutylicum

Abstract The expression of all sequenced acetone and butanol formation genes was followed using mRNA analysis during the shift from acidogenesis to solventogenesis in continuous culture of Clostridium acetobutylicum . Differential induction or derepression of the bdhA, bdhB , and adc genes as well as the sol operon was observed during the pH-induced shift. The order of induction of the three different butanol dehydrogenase genes was found to be bdhA-sol operon- bdhB , offering an explanation for the physiological role of the respective enzymes. Peak mRNA synthesis of an autolysin and a heat shock gene at the onset of solventogenesis was detected in addition to the above-mentioned genes. None of the hitherto sequenced genes of butanologenic enzymes was found to be involved in butanol production during the Methyl viologen-induced shift, indicating the presence of yet unknown genes encoding alcohol and aldehyde dehydrogenases.     

红三叶草活性成分及其在保健食品和医药中的应用

微量元素硒(Se)和异黄酮类化合物具有重要的生物学功能和药理作用,是目前食品保健、生物医学等领域的研究热点。红三叶草因富合异黄酮,同时具有较高富硒能力,是天然的植物有机硒资源,被认为是目前最有开发前途的保健食品和医药新资源之一,对其活性物质的研究也是相关领域最为炽热的研究热点。本文主要介绍了目前国内外对红三叶草主要活性成分、药理作用及其在保健食品和医药方面应用的研究进展,并对其进一步的应用进行了展望。     

Purification and Characterization of the Acidic Lectin from Winged Bean Seeds

Winged bean acidic lectin was purified by DEAE-Sephadex A-50 and affinity chromatography on N-acetylgalactosamine-agarose gel. The purified lectin was a glycoprotein homogeneous on polyacrylamide gel electrophoresis, isoelectric focusing, and gel filtration. The molecular weight of the lectin was 52,000 by gel filtration, and SDS-polyacrylamide gel electrophoresis gave a single component of molecular weight of 27,000. Its isoelectric point was 5.5. The acidic lectin was rich in acidic amino acids, and contained 2mol of methionine but no cystine. It also agglutinated both trypsinized and untreated human erythrocytes (types A, B, AB and O), but not rabbit erythrocytes. The hemagglutination was inhibited by d-galactose and related sugars. Modification of the acidic lectin with N-bromosuccinimide caused a concomitant loss of the hemagglutinating activity with oxidation of tryptophan residue. The acidic lectin was immunologically different from the purified winged bean basic lectin by double immunodiffusion using antiserum raised against the basic lectin.     

菜心中高等电点高活性的乙醇酸氧化酶同工酶的纯化和特性

乙醇酸氧化酶 (EC 1 1 3 15 ,GO)被认为只含4 0kD一种碱性亚基 ,是因为从多种植物中获得了具GO活性的蛋白 ,SDS PAGE后呈约 4 0kD单带[1] .菠菜GOcDNA编码约 370个氨基酸 ,即 4 0kD多肽 ,其碱 酸性氨基酸的比例高达 0 96 ,富含碱性氨基酸[2 ] .已克隆的GOcDNA在E .coli中表达