生物活性肽自动查询预测系统

论述了运用生物信息学方法和计算机技术,快速从由蛋白酶模拟酶解蛋白质而产生的大量未知生物活性的系列肽中,预测有生物活性的肽,以实现生物活性肽功能的预测。主要建立了生物活性肽数据库,应用已有生物活性肽作为序列比对的标准,实行大量未知生物活性的系列肽自动无人值守的和已知生物活性的肽序列比对查询,以发现新物种中包括动物和植物的具有新的生物活性的功能肽。应用该软件系统AQS成功地预测并发现了造血细胞增殖肽、成骨细胞生长肽以及高血压押制肽。     

马齿苋黄酮提取及其生物活性研究进展

马齿苋为药食两用野生植物,我国资源丰富.黄酮是马齿苋主要生物活性成分之一,具有抗氧化、抗衰老、抗肿瘤、抗炎、抑菌、降血糖和保肝护肝等多种生物活性,研究马齿苋黄酮提取及其生物活性对马齿苋开发应用具有重要意义.以近10年国内发表相关文献为依据,梳理综述马齿苋黄酮提取工艺及其生物活性研究进展,为马齿苋黄酮深入研究及开发应用提...     

乳清蛋白生物活性肽研究进展

以乳清蛋白为原料,经过酶解或发酵等方法可以获得独特理化性质的生物活性肽。乳清蛋白生物活性肽来源广、活性强、分子量小,在食品和医药行业有很高的应用研究价值,已经成为研究热点。随着制备、分离纯化以及鉴定技术的不断发展和成熟,越来越多的乳清蛋白生物活性肽被发现。本研究主要综述了乳清蛋白生物活性肽的制备、分离纯化、鉴定方法以及生物功能,并展望了乳清蛋白生物活性肽应用前景,以期为功能性乳清蛋白生物活性肽产品的开发与应用提供参考。     

灰树花多糖的分子修饰及其活性研究进展

灰树花是一种高蛋白低脂肪的食品,具有免疫调节、抗氧化和抗肿瘤等生物活性。其中,多糖是灰树花的主要活性成分之一。对多糖进行分子修饰是提高它原有的生物活性或增加新活性的重要途径之一。综述了灰树花多糖的分子修饰方法,以及修饰后灰树花多糖的生物活性及其构效关系的研究进展,以期为灰树花多糖的深入研究和开发利用提供参考。     

无患子属植物的化学成分及生物活性研究进展

本文对近30年来无患子属植物的化学成分和生物活性研究进展进行了综述,为该属植物的进一步开发利用提供参考.无患子属植物的化学成分主要包括挥发油、三萜皂苷、倍半萜苷类化合物等,这些化合物具有抑菌、抗肿瘤、保肝和表面活性等多方面的生物活性.     

藜科植物化学成分与生物活性的研究进展

藜科植物广泛分布于干旱和盐碱地区,我国约有38属184种,新疆是我国藜科植物分布最多的地区。藜科植物主要含有生物碱、甾体、萜类和黄酮化合物,其生物活性逐渐受到人们的关注。本文对该科植物的化学成分和生物活性的研究进展进行了综述。     

荚迷属植物化学成分及生物活性研究进展

不少荚迷属植物有悠久的药用历史,从该属植物中分离到的化学成分有二萜、三萜、环烯醚萜苷、黄酮类、木脂素及酚苷.二萜类化合物主要是vibsane型化合物,某些具有生物活性;三萜类化合物主要是齐墩果烷型和重排达玛烷型;环烯迷醚萜苷类其糖苷的连接位置主要在环烯迷醚的C11位上,C1位连有异戊烯基.生物活性研究发现一些提取物具有抗氧化作用,对A549、HT-29和PC-3和NUGC癌细胞有毒性.本文对国内外有.关荚迷属植物化学成分和生物活性的研究作一综述,为开发利用荚迷属植物资源提供科学依据.     

环二肽生物活性的研究进展

随着越来越多的天然产物环二肽被发现,人们对其各种生物活性的研究也随之增多.本文综述了近20年来,在环二肽及其类似物生物活性方面的研究进展,其中主要包括:胞间信息传递、抑制毒素、促癌细胞凋亡和镇痛作用等.     

生物活性低聚肽生理功能的研究进展

相比多肽，低聚肽具有优异的吸收机制与生物活性，本文主要从生物活性低聚肽生理功能的角度综述生物活性低聚肽的研究进展，并对生物活性低聚肽的研究前景进行了展望。     

烟曲霉素及其衍生物生物活性研究进展

烟曲霉素是一种从烟曲霉菌(Aspergillus fumigatus)提取液中分离出来的具有多种生物活性的抗生素。因其具有多种生物活性,已有多种衍生物被合成,并被应用于多种领域。主要介绍了烟曲霉素及其3种衍生物Fumagillin B、TNP-470和CKD-732的分子结构及生物活性,并总结了烟曲霉素及其衍生物在治疗蜜蜂和鱼类的微孢子虫病以及人类癌症和肥胖症等方面的作用。     

Anti-oxidant activities of curcumin and related enones

The natural product curcumin (diferuloylmethane, 1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione), obtained from the spice turmeric, exhibits numerous biological activities including anti-cancer, anti-inflammatory, and anti-angiogenesis activities. Some of these biological activities may derive from its anti-oxidant properties. There are conflicting reports concerning the structural/electronic basis of the anti-oxidant activity of curcumin. Curcumin is a symmetrical diphenolic dienone. A series of enone analogues of curcumin were synthesized that included: (1) curcumin analogues that retained the 7-carbon spacer between the aryl rings; (2) curcumin analogues with a 5-carbon spacer; and (3) curcumin analogues with a 3-carbon spacer (chalcones). These series included members that retained or were devoid of phenolic groups. Anti-oxidant activities were determined by the TRAP assay and the FRAP assay. Most of the analogues with anti-oxidant activity retained the phenolic ring substituents similar to curcumin. However, a number of analogues devoid of phenolic substituents were also active; these non-phenolic analogues are capable of forming stable tertiary carbon-centered radicals.     

Genome-wide screen for genes with effects on distinct iron uptake activities in Saccharomyces cerevisiae

We screened a collection of 4847 haploid knockout strains (EUROSCARF collection) of Saccharomyces cerevisiae for iron uptake from the siderophore ferrioxamine B (FOB). A large number of mutants showed altered uptake activities, and a few turned yellow when grown on agar plates with added FOB, indicating increased intracellular accumulation of undissociated siderophores. A subset consisting of 197 knockouts with altered uptake was examined further for regulated activities that mediate cellular uptake of iron from other siderophores or from iron salts. Hierarchical clustering analysis grouped the data according to iron sources and according to mutant categories. In the first analysis, siderophores grouped together with the exception of enterobactin, which grouped with iron salts, suggesting a reductive pathway of iron uptake for this siderophore. Mutant groupings included three categories: (i) high-FOB uptake, high reductase, low-ferrous transport; (ii) isolated high- or low-FOB transport; and (iii) induction of all activities. Mutants with statistically altered uptake activities included genes encoding proteins with predominant localization in the secretory pathway, nucleus, and mitochondria. Measurements of different iron-uptake activities in the yeast knockout collection make possible distinctions between genes with general effects on iron metabolism and those with pathway-specific effects.     

Distribution of enzyme activities in subcellular fractions of bovine retina.

Centrifugation of homogenates of bovine retinas to isopycnic equilibrium in sucrose density gradients yielded three partially overlapping bands of particles which were, in the order of increasing density: (a) photoreceptor cell (rod) outer segments; (b) plasma membranes, lysosomes, and large fragments of endoplasmic reticulum; and (c) mitochondria. The only enzyme activity investigated which had a peak coinciding only with outer segment fractions was guanylate cyclase. Enzyme activities with peaks in both the outer segment and denser fractions included 5'-nucleotidase and cyclic GMP phosphodiesterase. Enzyme activities with peaks only in the denser fractions included sodium and potassium ion-activated ATPase ((Na+ + K+)-ATPase), adenylate cyclase, cyclic AMP phosphodiesterase, beta-glucosidase, beta-galactosidase, and succinate-dependent cytochrome c reductase. These results suggest that some of the activities once thought to be present in rod outer segments are actually present in particles from elsewhere in the retina which contaminate rod outer segment preparations.     

大丁草属植物的化学成分和药理活性研究

本文概述了大丁草属植物的化学成分和药理活性研究。着重介绍了其中所含的香豆素类化合物的化学结构特点、光谱特征及生物活性。     

l-Phenylalanine Ammonia-lyase (Maize): Partial Purification and Response to Gibberellic Acid and Cycloheximide of l-Phenylalanine and l-Tyrosine Ammonia-lyase Activities

Extracts of maize leaf sheath tissue deaminate both l-phenylalanine and l-tyrosine. The activities with both substrates are enhanced by treating the plant with gibberellic acid. Both activities decrease rapidly at the same rate when tissue is incubated in a moist atmosphere, and this decrease can be slowed by treatment with cycloheximide. The ratio of the activities was constant throughout a series of purification steps which included acetone and ammonium sulfate precipitation, and passage through an agarose column. The two activities could not be separated by isoelectric focusing. These results support our earlier conclusion that both activities occur at the same catalytic site.     

Fractionation and Composition Studies of Skin Test-Active Components of Sensitins from Coccidioides immitis

Coccidioidin skin-test activities from mycelial culture filtrates and autolysates were partially purified. Major chemical constituents included 3-O-methylmannose, mannose, and amino acids.     

Effects of early androgens on sex-typed activities and interests in adolescents with congenital adrenal hyperplasia

The goal of this study was to examine the relation of early androgen exposure to sex-typed activities and interests in adolescence. Participants aged 9-19 years included 24 girls and 18 boys with congenital adrenal hyperplasia (CAH) and 16 unaffected sisters and 24 unaffected brothers who served as controls. Using standardized questionnaires, adolescents reported on their participation in sex-typed activities and interest in sex-typed occupations, and parents reported on the adolescents' activities. As hypothesized, girls with CAH showed sex-atypical preferences: increased interest in male-typical activities and careers and reduced interest in female-typical activities and careers compared to the unexposed control girls. These results extend findings of sex-atypical play in young girls with CAH and suggest that the sex-atypical activities and interests of females with CAH reflect direct effects of androgens on the developing brain rather than social responses to virilized genitalia. These results also suggest that population sex differences in activities and interests arise in part from sex differences in early androgens.     

Aminopeptidase activities present in tissues of Helix aspersa.

1. Tissues of Helix aspersa have been examined for the presence of aminopeptidase activities. 2. Enzyme activities were detected using synthetic peptide substrates containing the fluorescent leaving group 7-amino-4-methyl coumarin. The methods used included continuous fluorimetric assay and activity staining of enzymes in non-denaturing polyacrylamide gels. 3. Several types of peptidase activity were detected, including three distinct aminopeptidases which differ in molecular size and substrate preference.     

3'-Phosphatase activity in T4 polynucleotide kinase.

The purification of T4 polynucleotide kinase results in the copurification of an activity which will specifically remove the 3'-terminal phosphate from a variety of deoxyribonucleotides and ribonucleotides in the absence of ATP. This phosphatase activity requires magnesium, has a pH optiumum of 6.0, and is more active with deoxyribonucleotides than ribonucleotides. T4 polynucleotide kinase and the 3'-phosphatase activity copurify by gradient elution column chromatography on DEAE-cellulose, phosphocellulose, and hydroxylapatite. The two activities are included in and comigrate on Sephadex G-200. Polyacrylamide gel electrophoresis at PH 9.2 results in conigration of the two activities together with the major protein band. The two activities respond in parallel to heat inactivation at 35 degrees C and ATP, a substrate for the kinase only, protects both activities from heat inactivation. It is therefore suggested that the two activities are functions of the same protein molecule.     

Vitamin C partially reversed some biochemical changes produced by vitamin E deficiency

Feeding a basal diet free of vitamins E and C to weanling male rats for 8 months resulted in biochemical changes characteristic of vitamin E deficiency. These included increased liver thiobarbituric acid values; decreased blood GSH levels, plasma vitamin E levels, and glutathione peroxidase activities; and increased activities of plasma pyruvate kinase, glutamic-oxaloacetic transaminase, creatine kinase, lactic dehydrogenase, and malic dehydrogenase. Tube-feeding vitamin C for 21 days resulted in partial reversal effects on the above parameters except activities of glutathione peroxidase, lactic dehydrogenase, and malic dehydrogenase. The results suggest that vitamin C may spare in part the metabolism of vitamin E through its antioxidant property.