二氧化碳固定酶固碳效率及其对地衣芽孢杆菌代谢的影响

【背景】随着代谢工程与合成生物学的快速发展,通过对异养微生物进行代谢改造,利用生物法进行二氧化碳固定成为一个新的趋势。生物代谢途径中存在着大量固碳酶,这些酶尚待挖掘与应用,不同的酶固碳效率之间也缺少比较。【目的】在体外和体内对固碳功能和效率进行评价。【方法】选取3种固碳酶,即核酮糖1,5-二磷酸羧化加氧酶(ribose 1,5-diphosphate carboxylation oxygenase, RuBisCo)、磷酸烯醇式丙酮酸羧激酶(phosphoenolpyruvate carboxykinase, PCK)和乙酰辅酶A羧化酶(acetyl coenzyme A carboxylase, ACC)在大肠杆菌中异源表达并纯化。测定纯酶的酶活,并建立无细胞催化实验-液质联用评价酶固碳能力的方法。在厌氧发酵条件下检测代谢指标,比较过表达固碳酶的地衣芽孢杆菌相较于原始菌的代谢差异。【结果】3种酶均实现可溶性表达,纯酶的比酶活分别为66.43、1.16和12.52 U/mg。通过体外无细胞催化实验,ACC在3种酶中表现出最高的固碳效率。分别过表达了PCK、ACC的重组地衣芽孢杆菌,厌氧发酵主产物乳酸的转化率从48.6%分别提升至58.1%和59.7%。【结论】可以通过体外、体内结合的方式对固碳酶的效率进行评价,该研究可为固碳酶在微生物遗传改造中理性、精准地应用提供参考。     

嗜麦芽窄食单胞菌OUC_Est10全基因组测序及脂类水解酶多样性分析

[目的]本研究的目的是研究嗜麦芽窄食单胞菌OUC_Est10中脂类水解酶的多样性。[方法]使用离子交换层析、全基因组测序和异源表达三种方法研究嗜麦芽窄食单胞菌OUC_Est10中脂类水解酶的多样性。[结果]离子交换层析结果显示嗜麦芽窄食单胞菌OUC_Est10可以分泌多种脂类水解酶。通过全基因组测序,我们给出了该菌的全基因组序列,该基因组大小为4668743 bp,GC含量为66.25%。通过详细的基因组序列分析,我们从该基因组中找到33个可能具有脂类水解酶活性的假定基因。通过异源表达OUC_Est10中的5个假定脂类水解酶基因,来研究其催化特性的多样性,结果显示这些脂类水解酶具有不同的催化特性。[结论]我们证明了嗜麦芽窄食单胞菌OUC_Est10拥有多样的脂类水解酶,这暗示了它在不同领域中的应用潜力。     

The Biosynthesis and Metabolism of Acarbose in Actinoplanes sp. SE 50/110: A Progress Report

Abstract

The α-glucosidase inhibitor acarbose produced by Actinoplanes sp. SE50/110 is a pseudotetrasaccharide, which consists of an unsaturated cyclitol (carba-sugar), 4-amino-4,6-dideoxyglucose and maltose. The cyclitol (valienol) and the 4-amino-4,6-dideoxyglucose are linked via an N-glycosidic (imino) bond, forming the so-called acarviosyl moiety, which is primarily responsible for the inhibitory effect on α-glucosidases. The gene cluster encoding the biosynthetic genes for the synthesis of acarbose (acb-genes) was sequenced and 25 open reading frames belonging to the acb-gene cluster were identified. Based on the analysis of the enzymes encoded by the acb-cluster, the biosynthesis and ecological role of acarbose is described. The gene cluster includes genes which encode: proteins for the synthesis of the cyclitol; the enzymes for the synthesis of dTDP-4-amino-4,6-dideoxyglucose; glycosyltransferases for the condensation reactions; ATP-dependent exporters and importers; extracellular starch degrading enzymes; and intracellular acarbose modifying enzymes. Acarbose has a dual role for the producer: it inhibits α-glucosidic enzymes of competitors and functions as a carbophor for the uptake of glucose or starch molecules.     

杜比亚蟑螂肠道菌的分离鉴定及产消化酶功能菌株的筛选

【背景】杜比亚蟑螂(Blaptica dubia)可用于活体饲料、化妆品和医药保健品的生产,其肠道菌的研究对杜比亚蟑螂的饲养和肠道菌资源的开发与利用都十分重要。【目的】揭示杜比亚蟑螂肠道可培养菌的种类,筛选具有产消化酶功能的菌株,为理解肠道菌对宿主的影响机理及功能菌株的利用提供科学依据和研究材料。【方法】采用体外培养法获得杜比亚蟑螂肠道菌,结合形态学和分子生物学方法进行鉴定;用水解圈法分别筛选产纤维素酶、蛋白酶、脂肪酶和淀粉酶菌株。【结果】在杜比亚蟑螂肠道中共分离出4属7种细菌,其中芽孢杆菌属(Bacillus)2种,沙雷氏菌属(Serratia)和柠檬酸杆菌属(Citrobacter)各2种,肠球菌属(Enterococcus)1种。从获得的20个菌株中筛选出10个具有产消化酶功能的菌株。其中,芽孢杆菌属的菌株D6、D12和D20具有产纤维素酶、蛋白酶、淀粉酶及脂肪酶4种消化酶的功能;沙雷氏菌属的菌株D3、D7、D9、D11和D15具有产纤维素酶、蛋白酶和脂肪酶3种消化酶的能力;柠檬酸杆菌属的菌株D5具有产纤维素酶的功能;肠球菌属的菌株D17具有产蛋白酶的能力。【结论】杜比亚蟑螂肠道多种细菌具有产消化酶帮助降解大分子营养物质的功能,可通过协助食物消化影响宿主健康。菌株D12、D7和D11分别具有最强产纤维素酶、蛋白酶和脂肪酶的能力,是可进一步开发利用的肠道功能菌株资源。     

Evolutionarily Conserved Optimization of Amino Acid Biosynthesis

The “cognate bias hypothesis” states that early in evolutionary history the biosynthetic enzymes for amino acid x gradually lost residues of x, thereby reducing the threshold for deleterious effects of x scarcity. The resulting reduction in cognate amino acid composition of the enzymes comprising a particular amino acid biosynthetic pathway is predicted to confer a selective growth advantage on cells. Bioinformatic evidence from protein-sequence data of two bacterial species previously demonstrated reduced cognate bias in amino acid biosynthetic pathways. Here we show that cognate bias in amino acid biosynthesis is present in the other domains of life—Archaebacteria and Eukaryota. We also observe evolutionarily conserved underrepresentations (e.g., glycine in methionine biosynthesis) and overrepresentations (e.g., tryptophan in asparagine biosynthesis) of amino acids in noncognate biosynthetic pathways, which can be explained by secondary amino acid metabolism. Additionally, we experimentally validate the cognate bias hypothesis using the yeast Saccharomyces cerevisiae. Specifically, we show that the degree to which growth declines following amino acid deprivation is negatively correlated with the degree to which an amino acid is underrepresented in the enzymes that comprise its cognate biosynthetic pathway. Moreover, we demonstrate that cognate fold representation is more predictive of growth advantage than a host of other potential growth-limiting factors, including an amino acid’s metabolic cost or its intracellular concentration and compartmental distribution. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users. Reviewing Editor: Dr. Niles Lehman Ethan O. Perlstein and Benjamin L. de Bivort contributed equally to this work.     

Inhibition of human cytochromes P450 2A6 and 2A13 by flavonoids,acetylenic thiophenes and sesquiterpene lactones from Pluchea indica and Vernonia cinerea

The human liver cytochrome P450 (CYP) 2A6 and the respiratory CYP2A13 enzymes play role in nicotine metabolism and activation of tobacco-specific nitrosamine carcinogens. Inhibition of both enzymes could offer a strategy for smoking abstinence and decreased risks of respiratory diseases and lung cancer. In this study, activity-guided isolation identified four flavonoids 1–4 (apigenin, luteolin, chrysoeriol, quercetin) from Vernonia cinerea and Pluchea indica, four hirsutinolide-type sesquiterpene lactones 5–8 from V. cinerea, and acetylenic thiophenes 9–11 from P. indica that inhibited CYP2A6- and CYP2A13-mediated coumarin 7-hydroxylation. Flavonoids were most effective in inhibition against CYP2A6 and CYP2A13, followed by thiophenes, and hirsutinolides. Hirsutinolides and thiophenes exhibited mechanism-based inhibition and in irreversible mode against both enzymes. The inactivation kinetic K_I values of hirsutinolides against CYP2A6 and CYP2A13 were 5.32–15.4 and 0.92–8.67 µM, respectively, while those of thiophenes were 0.11–1.01 and 0.67–0.97 µM, respectively.     

基于生物信息学分析从Streptomyces albofaciens JCM 4342中发现2,3-二羟基苯甲酸酯-L-丝氨酸脱水三聚体和二聚体天然产物

[背景] 铁是细菌生长的基本元素,而三价铁在自然水环境中几乎无法溶解。细菌已经进化出产生各种铁载体的能力,以促进铁的吸收。对于链霉菌,其特有的铁载体是去铁胺,同时它们也可以产生其他结构的铁载体,如ceolichelin、白霉素、肠杆菌素（enterobactin）和griseobactin。[目的] 揭示链霉菌中铁载体生物合成基因簇（Biosynthetic Gene Clusters,BGCs）的分布特点和基因簇特征,并探索其所合成铁载体的化合物结构。[方法] 利用生物信息学工具系统地分析308个具有全基因组序列信息的链霉菌中的铁载体生物合成基因簇,并用色谱和波谱方法分离和表征肠杆菌素相关天然产物。[结果] 发现Streptomyces albofaciens JCM 4342和其他少数菌株同时含有一个缺少2,3-二羟基苯甲酸（2,3-DHB）生物合成基因的孤立的肠杆菌素生物合成基因簇和另外一个推测可合成griseobactin的基因簇。从S.albofaciens JCM 4342发酵液中鉴定出4个肠杆菌素衍生的天然产物,包括链状2,3-二羟基苯甲酸酯-l-丝氨酸（2,3-DHBS）的三聚体和二聚体以及它们的脱水产物。[结论] 2个基因簇间存在一种特别的协同生物合成机制。推测是griseobactin基因簇负责合成2,3-DHB,而孤立的肠杆菌素基因簇编码的生物合成酶可夺取该底物,进而完成上述4种肠杆菌素衍生天然产物的生物合成。     

Comparison of Kinetic Properties Between Plant and Fungal Amine Oxidases

Abstract

Kinetic properties of novel amine oxidases isolated from a mold Aspergillus niger AKU 3302 were compared to those of typical plant amine oxidase from pea seedling (EC 1.4.3.6). Pea amine oxidase showed highest affinity with diamines, such as putrescine and cadaverine, while fungal enzymes oxidized preferably n-hexylamine and tyramine. All enzymes were inhibited by carbonyl reagents, copper chelating agents, some substrate analogs and alkaloids, but there were quite significant differences in the sensitivity and inhibition modes. Aminoguanidine, which strongly inhibited pea amine oxidases showed only little effect on fungal enzymes. Substrate analogs such as 1,5-diamino-3-pentanone and l-amino-3-phenyl-3-propanone, which were potent competitive inhibitors of pea amine oxidases, inhibited fungal enzymes much more weakly and non competitively. Also various alkaloids behaving as competitive inhibitors of pea amine oxidases inhibited the fungal enzymes non competitively. Very surprising was the potent inhibition of fungal enzymes by artificial substrates of pea amine oxidases, E- and Z-1,4-diamino-2-butene. The relationships between the different inhibition modes and possible binding at the active site are discussed.     

野油菜黄单胞菌中3-羟基脂酰ACP脱水酶FabZ的生理功能

【背景】野油菜黄单胞菌(Xanthomonas campestris pv. campestris, Xcc)引起十字花科植物黑腐病,在全球范围内造成经济损失,亟须深入研究其致病机理,开发新的黑腐病防控措施。细菌脂肪酸合成系统不仅为细胞膜合成提供原料,其中间代谢产物还是许多生物活性分子合成的底物,具有重要的生理功能,也是抗菌药物筛选的重要靶标。【目的】研究XccfabZ对扩散信号分子(diffusible signal factor, DSF)类信号产量、致病力、胞外酶、胞外多糖和运动性等方面的影响。【方法】利用报告菌株检测法分析了不同替换突变株的DSF类群体感应信号产量。利用同源重组原理,在DSF类信号高产菌株中获得替换突变株,利用高效液相色谱(highperformanceliquid chromatography, HPLC)法测定DSF类信号产量。利用剪叶法检测替换突变株对寄主植物甘蓝的致病力,并分析了不同菌株的胞外多糖、胞外酶和运动性差异。【结果】报告菌株检测法和HPLC法都证明大肠杆菌fabZ替换突变株(XccΔfabZ/pSRK-EcfabZ)中DSF类信号产量显著下降。...     

马蜂肠道菌的分离鉴定及产消化酶功能菌株的筛选

【背景】马蜂(Vespa mandarinia Smith)可以防治多种田间害虫,还具有药用价值,其肠道菌群结构和功能还有待研究。【目的】获得马蜂肠道可培养细菌并筛选出具有产消化酶功能的菌株,为理解肠道菌对宿主的影响机理及功能菌株的利用提供科学依据和研究材料。【方法】采用传统细菌分离培养法获得马蜂肠道菌,结合形态学以及16S rRNA基因序列分析进行鉴定;利用水解圈法分别筛选产蛋白酶、脂肪酶、淀粉酶和纤维素酶菌株;通过测量水解圈D与菌落直径d的比值,比较不同细菌的产酶能力。【结果】在马蜂肠道中共分离出6属10种细菌,其中芽孢杆菌属5种,肠球菌属、葡萄球菌属、明串珠菌属、乳球菌属和不动杆菌属各1种。从获得的61个菌株中筛选出6个具有产消化酶功能的菌株。其中,苏云金芽孢杆菌V44具有产蛋白酶、淀粉酶、脂肪酶和纤维素酶4种消化酶的能力;粪肠球菌V6具有产淀粉酶、蛋白酶和脂肪酶3种消化酶的能力;蜡样芽孢杆菌V43具有产蛋白酶、淀粉酶和纤维素酶3种消化酶的能力;粪肠球菌V20、蜡样芽孢杆菌V19和维德曼氏芽孢杆菌V22均具有产蛋白酶的能力。【结论】马蜂肠道细菌资源较丰富,部分有产消化酶的功能,可帮助马蜂消化食物,对宿主健康有一定影响。本研究筛选的6个菌株都能产蛋白酶,其中菌株V43和V44分别具有最强产淀粉酶和脂肪酶的能力,是可进一步开发利用的肠道功能菌株资源。     

Synthesis,biological evaluation and docking studies of new pyrrolo[2,3-d] pyrimidine derivatives as Src family-selective tyrosine kinase inhibitors

In this study, the synthesis and potential enzyme interactions of new Pyrrolo[2,3-d]pyrimidine derivatives along with their inhibitory activity against SFK enzymes such as Fyn, Lyn, Hck, and c-Src were reported. The results indicated that compounds were slightly active of tested SFK enzymes in comparison with PP2 for Fyn, A-419259 for Lyn and CGP77675 for c-Src. Compound N-((2-amino-4-oxo-4,7-dihydro-3H-pyrrolo[2,3-d]pyrimidin-5-yl)methyl)-4-(3,4-dimethoxyphenyl)butanamide (5) was identified as a non-selective slight inhibitor against Fyn, Lyn and c-Src. However, compounds did not show any inhibitory effects on Hck. Docking studies were performed to analyze the binding mode of compounds against SFKs. The best interaction was obtained between compound 5 and the active site of Fyn and c-Src enzymes in comparison with reference compounds PP2 and CGP77675, respectively.     

Protein crosslinking: Uses in chemistry,biology and biotechnology

Abstract

Protein crosslinking is a part of many biological processes and is also carried out in vitro under several controllable conditions with the help of any of the commercially available bifunctional reagents. Many biotechnological applications utilize stable and/or reusable crosslinked enzymes such as soluble intramolecularly crosslinked enzymes; soluble bioconjugates of enzymes with other enzymes/proteins or polymers; chemically aggregated enzymes, chemically crosslinked enzyme aggregates and crosslinked enzyme crystals. The review after indicating how protein crosslinking is at the heart of such diverse processes/technology concludes with discussion of few applications which are currently drawing considerable attention.     

Hydroxylation of steroids by Fusarium oxysporum, Exophiala jeanselmei and Ceratocystis paradoxa

The potential of Fusarium oxysporum var. cubense UAMH 9013 to perform steroid biotransformations was reinvestigated using single phase and pulse feed conditions. The following natural steroids served as substrates: dehydroepiandrosterone (1), pregnenolone (2), testosterone (3), progesterone (4), cortisone (5), prednisone (6), estrone (7) and sarsasapogenin (8). The results showed the possible presence of C-7 and C-15 hydroxylase enzymes. This hypothesis was explored using three synthetic androstanes: androstane-3,17-dione (9), androsta-4,6-diene-3,17-dione (10) and 3α,5α-cycloandrost-6-en-17-one (11). These fermentations of non-natural steroids showed that C-7 hydroxylation was as a result of that position being allylic. The evidence also pointed towards the presence of a C-15 hydroxylase enzyme.The eleven steroids were also fed to Exophialajeanselmei var. lecanii-corni UAMH 8783. The results showed that the fungus appears to have very active 5α and 14α-hydroxylase enzymes, and is also capable of carrying out allylic oxidations.Ceratocystis paradoxa UAMH 8784 was grown in the presence of the above-mentioned steroids. The results showed that monooxygenases which effect allylic hydroxylation and Baeyer–Villiger rearrangement were active. However, redox reactions predominated.     

Studies on DNA-related enzymes to elucidate molecular mechanisms underlying genetic information processing and their application in genetic engineering

ABSTRACT

Recombinant DNA technology, in which artificially “cut and pasted” DNA in vitro is introduced into living cells, contributed extensively to the rapid development of molecular biology over the past 5 decades since the latter half of the 20^th century. Although the original technology required special experiences and skills, the development of polymerase chain reaction (PCR) has greatly eased in vitro genetic manipulation for various experimental methods. The current development of a simple genome-editing technique using CRISPR-Cas9 gave great impetus to molecular biology. Genome editing is a major technique for elucidating the functions of many unknown genes. Genetic manipulation technologies rely on enzymes that act on DNA. It involves artificially synthesizing, cleaving, and ligating DNA strands by making good use of DNA-related enzymes present in organisms to maintain their life activities. In this review, I focus on key enzymes involved in the development of genetic manipulation technologies.     

巴氏杆菌糖酵解酶的黏附作用研究

巴氏杆菌（主要是多杀性巴氏杆菌）可以引起多种动物疫病（巴氏杆菌病）,同时也引起人类感染发病。[目的] 研究巴氏杆菌糖酵解酶对宿主细胞（兔肾细胞）和两种常见分子[纤连蛋白（fibronectin,Fn）和血浆纤维蛋白溶解酶原（plasminogen,Plg）]的黏附作用。[方法] 采用原核表达系统对多杀性巴氏杆菌的糖酵解酶进行表达并纯化及制备多克隆抗体,通过菌体表面蛋白定位检测、黏附与黏附抑制等实验探究巴氏杆菌糖酵解酶的黏附作用。[结果] 菌体表面蛋白检测结果显示除烯醇化酶和丙酮酸激酶外的7个糖酵解酶在多杀性巴氏杆菌表面存在。这7个糖酵解酶均能黏附兔肾细胞,但仅有磷酸葡萄糖异构酶的多克隆抗体能对多杀性巴氏杆菌黏附宿主细胞产生抑制作用。Far Western blotting结果显示9个糖酵解酶均能结合宿主Fn和Plg。招募抑制实验结果显示磷酸葡萄糖异构酶、醛缩酶、磷酸甘油酸变位酶的抗体对多杀性巴氏杆菌结合Fn和Plg都有抑制作用,磷酸果糖激酶、丙糖磷酸异构酶、甘油醛-3-磷酸脱氢酶、磷酸甘油激酶抗体仅对多杀性巴氏杆菌结合Fn或Plg有抑制作用。[结论] 多杀性巴氏杆菌糖酵解酶成员葡萄糖异构酶、磷酸果糖激酶、醛缩酶、丙糖磷酸异构酶、甘油醛-3-磷酸脱氢酶、磷酸甘油激酶、磷酸甘油酸变位酶在多杀性巴氏杆菌黏附宿主细胞或分子过程中发挥作用。该研究的完成将加深巴氏杆菌病分子发病机制的认识,并为巴氏杆菌病的诊断标识筛选、新型疫苗创制和药物靶标筛选等提供基础数据。     

Biomarkers of antioxidant status and lipid peroxidation in elderly patients with hypertension

Objective: The objective of the present study was to examine selected parameters of the blood redox system in elderly patients with hypertension.examine selected parameters of the blood redox system in elderly patients with hypertension. Methods: We analyzed differences in redox-associated molecules and enzymes among elderly hypertensive subjects (age above 65?years, n?=?49) and two groups of normotensive subjects (<65 years old – Control group I; n?=?27, and >65 – Control group II; n?=?30). Results: Decreased activity of antioxidant enzymes, increased lipid peroxidation and reduced production of nitric oxide were observed in hypertensive subjects, compared to healthy younger controls, or those of the same age. In healthy controls, an age-related decrease in the production of nitric oxide and the activities of SOD-1 and GPx-1 was also evident. The pathology of hypertension was characterised by further, significant decreases in the values of these parameters. When the subgroups of females and males were compared to their respective controls, a compromised redox balance was observed that was more evident in female hypertensives. Discussion: Hypertension in elderly patients is accompanied by changes in biomarkers of antioxidant status and lipid peroxidation status, which significantly differ from those observed in healthy ageing subjects. Our study also suggests that the relationship of gender and changes in redox balance with regard to hypertension should be further explored.     

An efficient method for mutant library creation in Pichia pastoris useful in directed evolution

Abstract

The yeast Pichia pastoris is being increasingly used as a host for expressing enzymes on a large scale, but application in directed evolution requiring efficient expression of libraries of mutants is hampered due to the time-consuming multistep procedure which includes an intermediate bacterial host (Escherichia coli). Here we introduce a fast and highly simplified method to produce gene libraries in P. pastoris expression vectors. For the purpose of illustration, Galactomyces geotrichum lipase 1 (GGL1) was used as the catalyst in the enantioselective hydrolytic kinetic resolution of 2-methyldecanoic acid p-nitrophenyl ester, the gene mutagenesis method being saturation mutagenesis. The phosphorylated linear plasmid which is integrated in the yeast genome was obtained by combination of partially overlapped fragments using overlap-extension PCR. An intermediate bacterial host is not necessary, neither are restriction enzymes. This method is also applicable when using error-prone PCR for library creation in directed evolution.     

Thermodynamics of partitioning of chitinase and laminarinase in a soya lecithin liposome system and their antifungal effect against Fusarium oxysporum

Abstract

The goal of the present work was to compare the partitioning behavior of chitinase and laminarinase (from Trichoderma spp.) in soya lecithin liposomes at different temperatures and examine the activity of the resulting microencapsulated enzymes against Fusarium oxysporum. In both cases the partition coefficients (K_o/w) were greater than 1, indicating affinity of the enzymes for microencapsulation in liposomes. Enthalpy calculations indicated that the process was endothermic in the case of laminarinase and exothermic in the case of chitinase. Soya lecithin liposomes were stable for more than 20 days. The stability of the immobilized enzyme was increased in the case of chitinase, but was not changed in the case of laminarinase. Although the antifungal effects of individual immobilized preparations decreased after microencapsulation compared with non-immobilized enzymes, they were increased by the synergistic effect of both encapsulated enzymes. The application of free or immobilized enzymes was also shown to enhance the inhibitory effect of the chemical fungicide, thiabendazole, on F. oxysporum.     

Cloning and identification of the Frigocyclinone biosynthetic gene cluster from Streptomyces griseus strain NTK 97

ABSTRACT

Frigocyclinone is a novel antibiotic with antibacterial and anticancer activities. It is produced by both Antarctica-derived Streptomyces griseus NTK 97 and marine sponge-associated Streptomyces sp. M7_15. Here, we first report the biosynthetic gene cluster of frigocyclinone in the S. griseus NTK 97. The frigocyclinone gene cluster spans a DNA region of 33-kb which consists of 30 open reading frames (ORFs), encoding minimal type II polyketide synthase, aromatase and cyclase, redox tailoring enzymes, sugar biosynthesis-related enzymes, C-glycosyltransferase, a resistance protein, and three regulatory proteins. Based on the bioinformatic analysis, a biosynthetic pathway for frigocyclinone was proposed. Second, to verify the cloned gene cluster, CRISPR-Cpf1 mediated gene disruption was conducted. Mutant with the disruption of beta-ketoacyl synthase encoding gene frig20 fully loses the ability of producing frigocyclinone, while inactivating the glycosyltransferase gene frig1 leads to the production of key intermediate of anti-MRSA anthraquinone tetrangomycin.     

Cd24a和前列腺素代谢相关酶在PCOS小鼠模型卵巢颗粒细胞中表达水平的实验研究

目的:探讨Cd24a分子和前列腺素代谢相关酶在多囊卵巢综合征(polycystic ovary syndrome, PCOS)小鼠模型卵巢颗粒细胞中的表达水平。方法:取20只雌性C57BL/6小鼠,随机分为对照组(正常小鼠)和实验组(应用脱氢表雄酮建立PCOS小鼠模型),每组各10只。对照组小鼠于颈背部连续皮下注射20天芝麻油溶液(0.1 m L/100 g)。实验组应用脱氢表雄酮(6 mg/100 g)联合芝麻油溶液(0.1 m L/100 g)连续颈背部皮下注射20天。经苏木精-伊红染色观察两组小鼠卵巢组织病理学改变。应用实时荧光定量PCR法对小鼠卵巢颗粒细胞中Cd24a分子和前列腺素代谢相关酶m RNA表达量进行检测。结果:实验组体重显著高于对照组(P0.05);实验组小鼠卵巢呈多囊样改变,卵泡中颗粒细胞数量减少,闭锁卵泡增多,闭锁卵泡直径明显大于对照组;实验组Cd24a分子和前列腺素代谢相关酶m RNA表达量较对照组存在显著差异(P0.05)。结论:PCOS小鼠卵巢颗粒细胞中Cd24a分子和前列腺素代谢相关酶表达量异常,提示Cd24a分子可能与PCOS疾病发生相关。