海洋微生物次级代谢产物及其抑菌活性研究进展

海洋微生物能够产生大量结构新颖、活性独特的次级代谢产物,这为药物先导化合物的发现提供了重要来源,已成为海洋药物研究的热点。本文综述了自2000年至今从海洋真菌、细菌、放线菌报道的具有抑菌活性次级代谢产物的研究进展,共涉及到活性化合物101个,结构类型主要包括大环内酯类、生物碱类、醌类、肽类和萜类等,其中26个化合物含有氯、溴或硫元素;体外抑菌活性测试结果表明,有33个化合物的MIC<5μg.mL-1。     

具有抗菌活性的植物内生微生物代谢产物研究进展

目的综述近年来具有抗菌活性的植物内生微生物次级代谢产物研究进展。方法通过查阅30篇国内外文献,以化合物结构类型为纲,抗菌活性为主线,对植物内生微生物次级代谢产物的研究进行总结。结果植物内生微生物次级代谢产物结构类型丰富,抗菌活性良好。结论植物内生微生物代谢产物对于抗菌药物的研发具有重要意义和广阔前景。     

药用微生物代谢产物筛选的新进展

微生物生长繁殖过程中产生的代谢产物种类繁多,结构各异,是寻找生物活性物质的重要天然宝库之一。自Fleming发现青霉素之后,人们不断从微生物代谢产物中筛选到有价值的抗菌药物,为人类抗感染疾病的治疗作出了极大贡献。随着抗生素数量的增加,随机筛选抗生素的重复机率高,鉴别工作量大。以致人们一度对从微生物代谢物中寻找抗生素丧失信心。近年来,生物学各相关学科的发展及各种新技术的应用,基于酶抑制剂,抗原-抗体,受体-配基相互作用原理和应用生物技术建立了许多各具特色的筛选方法,新发现抗生素的种类和数量不断增加。从微生物代谢物中寻找抗生素仍不失为新抗生素研究的重要途径之一。     

海洋微生物次级代谢产物抗炎作用研究进展

炎症作为机体抵抗有害刺激修复损伤组织的防御反应，参与多种疾病的发展进程，严重危害人类生命健康。而临床常用的抗炎药物有一定的不良反应，寻找一些高效、低毒的抗炎先导化合物仍是一个重要方向。海洋作为各类生物资源的宝库，由于海洋生态环境的特殊性(高压、高盐，低氧等)，使得许多海洋生物在生命过程中产生大量具有特殊结构和抗炎活性的天然产物，成为炎症新药物研发的重要来源。本文总结了2016-2021年从放线菌、真菌、细菌三类海洋微生物中分离出的约73种天然产物，并对其在抑制炎症活性方面进行综述，以期望为今后的研究提供借鉴和启发。     

海洋微生物活性代谢产物的研究进展

研究海洋微生物活性物质 ,不但能发现结构新颖的化合物 ,而且能寻找到新的强效抗生素和抗病毒等活性的新药以及其它有用物质 ,这一新兴领域的研究在理论上和维护人类健康方面都有重大意义。本文综述了 2 0 0 0年以来对海洋微生物 (包括海洋细菌、蓝细菌、放线菌、真菌 )活性代谢产物的研究进展 ,共引用文献 6 9篇 ,包括 12 9个活性代谢产物。重点描述了这些化合物的相关生理活性 ,产生它们的微生物及微生物的采集地。     

海洋微生物抗肿瘤代谢产物的研究进展

近10年来,从海洋微生物中分离到许多结构新颖的抗肿瘤代谢产物。本文按微生物种类,综述了近十年海洋细菌、海洋真菌抗肿瘤代谢产物的研究进展。     

深海来源的微生物抗肿瘤活性筛选及次级代谢产物的初步研究

目的 对来自深海的海水、海泥样品进行了微生物分离并通过抗肿瘤活性筛选获得活性菌株,并研究活性菌株c2b的次级代谢产物.方法 从样品中选择性分离得到真菌,并采用海虾生物致死法和人体慢性艇性白血病细胞(K562)为筛选模型对分离得到真菌的发酵产物进行抗肿瘤活性筛选;采用溶剂萃取、硅胶柱色谱及制备HPLC等分离手段对c2b菌株发酵产物的活性部位进行了活性追踪分离,通过理化性质及渡谱学手段进行化学结构鉴定,以SRB法评价了化合物的抗肿瘤活性.结果与结论 从深海来源的样品中共分离获得29株真菌,其中7株具有细胞毒活性;从c2b活性菌株的发酵产物中分离得到6个单体化合物(1～6),其化学结构分别鉴定为N-乙酰色氨(1),chrysogine(2),过氧化麦角甾醇(3),5,8-epidioxy-24-methylcholesta-6,22-dien-3β-ol(4),cerevisterol(5)和(4E,8E)-N-[(2'R,3'E)-2'-hydroxy-3'-hexadecenoyl]-1-O-β-D-glycopyranosyl-9-methyl-4,8-sphingadiene(6),其中化合物3,4对小鼠乳腺癌细胞(tsFT210)具有中等强度的细胞毒活性.     

来源于微生物代谢产物的溶栓药物研究进展

血栓性疾病是威胁人类健康的重要疾病,而溶栓酶是治疗血栓性疾病最有效的药物,但其不良反应限制了临床应用。寻找高效低毒的溶栓药物是目前研究的热点问题,来源于微生物代谢产物的溶栓酶是一种重要的溶栓酶,1989-2008年间各国研究人员相继报道了很多能够产生溶栓酶的微生物,主要有β-溶血链球菌、金黄色葡萄球菌、链霉菌、假单胞菌属、杆菌、海洋绿藻类、真菌类等。文中全面介绍了这几类微生物产生的溶栓酶,并着重阐述了其化学结构特点和溶栓机制,说明微生物代谢产物是溶栓药物的重要来源。     

海绵共附生微生物活性次级代谢产物的研究进展

目的综述海绵共附生微生物次级代谢产物的生物活性及研究进展。方法查阅文献。进行整理和归纳。结果与结论从海绵共附生微生物中已分离得到许多结构独特，活性多样的次级代谢产物。其中有些具有潜在的药用价值。     

海洋微生物次级代谢产物生物合成的研究进展

海洋微生物次级代谢产物往往具有新颖的化学结构,蕴含着独特的生物合成途径、酶学机理和不同于陆生放线菌次级代谢产物的生物合成机制。自从2000年第一例海洋微生物天然产物enterocin的生物合成基因簇被阐明以来,迄今已克隆和鉴定了27种海洋微生物次级代谢产物的完整生物合成基因簇。这些次级代谢产物的生物合成主要源于四种途径,包括聚酮合酶途径,非核糖体肽合成酶途径,聚酮-非核糖体肽合成酶杂合途径,以及其他途径。本文综述了近年来一些重要海洋微生物活性次级代谢产物的生物合成途径,以及组合生物合成技术在海洋微生物次级代谢产物结构多样化方面的应用。     

Biomolecular-chemical screening: a novel screening approach for the discovery of biologically active secondary metabolites. III. New DNA-binding metabolites

Based on the chemical screening technique, biomolecular-chemical screening has been developed which makes use of two-dimensional TLC analysis of microbial extracts and combines thin-layer chromatography (RP-18) with binding studies towards DNA. In the first dimension the metabolites of the crude microbial extract are separated, and in the second dimension binding properties towards DNA are analysed. An initial screening program with 500 microbial extracts prepared by solid-phase extraction with XAD-16 resin resulted in 17 samples which contained metabolites with significant DNA-binding behavior. Fermentation, isolation and structural characterization led to already known metabolites [phenazine-1,6-dicarboxylate (1), phencomycin (2), 11-carboxy-menoxymycin B (3), soyasaponine I (4), and (8S)-3-(2-hydroxypropyl)-cyclohexanone (5)], as well as to new secondary metabolites. Fermentation of the producing organisms of the new DNA-binding metabolites, ent-8,8adihydro-ramulosin (6). (2R,4R)-4-hydroxy-2-(1,3-pentadienyl)-piperidine (7), (5R)-dihydro-5-pentyl-4'-methyl-4'-hydroxy-2(3H)-furanone (8), and seco-4,23-hydroxyoleane-12-en-22-one-3-carboxylic acid (9), as well as isolation, structural characterization, and physico-chemical properties are reported.     

Exploitation of heparanase inhibitors from microbial metabolites using an efficient visual screening system

In this paper we describe the establishment of an efficient visual method for screening heparanase inhibitors, and we present the results of screening 10,000 microbial culture broths. Heparanase-overexpressing stable clones of the human hepatocellular carcinoma HepG2 cells were established and used as an enzyme source. Digestion of heparan sulfate (HS) was detected using novel HS-containing tablets or SDS-polyacrylamide gel electrophoresis. This method was able to find suramin, a known heparanase inhibitor, from a library of typical enzyme inhibitors. By screening 10,000 culture broths of microorganisms (actinomycetes, fungi, and bacteria) an actinomycete strain, RK99-A234, was found to have heparanase inhibitory activity. RK-682 was identified in the fermentation broth as a heparanase inhibitor, IC50 = 17 microM.     

Biomolecular-chemical screening: a novel screening approach for the discovery of biologically active secondary metabolites. II. Application studies with pure metabolites

The novel screening strategy called "biomolecular-chemical screening" combines the advantages of the chemical screening approach--the analysis of the chromatographic and chemical behaviour of secondary metabolites on TLC plates--with binding studies of these molecules with bio-macromolecules like DNA. This approach was advantageously used to detect the interaction of pure compounds with DNA. In order to prove the reliability of the biomolecular-chemical screening and to examine DNA-binding properties, 470 pure secondary metabolites were analysed by this method. Besides the confirmation of already known binders with the TLC-based method, for a number of natural products DNA-binding properties were discovered for the first time. In consequence, binding of pure compounds can be measured by 1D TLC in a reliable and easy manner, in which DNA is applied together with the test compound at the starting spot. Analysis is performed via differences in Rf-values in comparison to a reference chromatogram without DNA.     

A new structural class of proteasome inhibitors identified by microbial screening using yeast-based assay

A yeast-based growth interference assay was developed utilizing a yeast strain in which expression of Xenopus cyclin A1 was induced to elevate cell division cycle 28 (Cdc28) kinase activity. Since the hyperactivation of Cdc28 kinase in yeast results in a growth-arrest phenotype, compounds which could rescue the cyclin A1-induced growth arrest might be potential new, antitumor drug candidates acting on the cyclin-dependent, kinase-mediated, cell cycle regulation pathway. In the course of our microbial screening program, the new Streptomyces metabolites, belactosins, were identified. As reported previously, belactosin A induced cell cycle arrest at G2/M phase in human cancer cells. However, the molecular mechanism of action was unknown. We herein demonstrate the proteasome inhibition by belactosin A. Belactosin A did not inhibit yeast Cdc28 kinase and human cyclin-dependent kinase in vitro. On the other hand, it inhibited the chymotrypsin-like activity of the rabbit 20S proteasome. From the initial SAR studies, we identified a hydrophobic belactosin A derivative, KF33955, which exhibited a 100-fold greater growth-inhibitory activity against HeLa S3 cells than belactosin A, presumably due to its higher cell permeability. The biochemical analysis using KF33955 suggested that the proteasome inhibitory activity of KF33955 were irreversible and required the beta-lactone moiety to inhibit the proteasome. KF33955 increased the intracellular levels of protein ubiquitination in NIH3T3 cells. In addition, KF33955 treatment resulted in the accumulation of known proteasome substrates in HeLa S3 cells. These results identify belactosin A as a useful lead compound to target proteasome for the treatment of disease whose etiology is dependent on the unregulated ubiquitin-proteasome pathway.     

拓展微生物药源活性新菌株资源的新方法探索

在药源微生物活性产物研究中,分离得到的绝大多数菌株往往因无活性而被大量闲置或被选择销毁,造成前期投入的极大浪费和菌株资源开发利用效率严重低下。因此,如何将大量无活性菌株有效转化成活性菌株从而拓展药源微生物资源已成为重要研究课题。本课题组近几年一直在探索开展海洋来源无活性野生菌株的活性化转化与新产活性产物研究,并在无活性放线菌和真菌相关研究中取得了较好进展。本文简要归纳介绍包括尚未详细报道的新近进展在内的部分研究结果。     

Polyphenols in lahpet-so and two new catechin metabolites produced by anaerobic microbial fermentation of green tea

The phenolic constituents of lahpet-so, a traditional postfermented tea of Myanmar produced under anaerobic conditions, were examined. The major polyphenols were identified to be pyrogallol and 4′-hydroxyphenyl-3-(2′′,4′′,6′′-trihydroxyphenyl)-propan-2-ol, 3′,4′-dihydroxyphenyl-3-(2′′,4′′,6′′-trihydroxyphenyl)-propan-2-ol, and 3′,4′,5′-trihydroxyphenyl-3-(2′′,4′′,6′′-trihydroxyphenyl)-propan-2-ol. The hydroxydiphenylpropan-2-ols were identical to the initial metabolites produced from green tea catechins by mammalian intestinal bacteria. In addition, an anaerobic mixed-fermentation experiment using lahpet-so and Japanese commercial green tea afforded two new catechin degradation products together with known compound bruguierol B and the above-mentioned catechin metabolites. Based on spectroscopic evidence, the structures of the new compounds were concluded to be 4-(2,5-dihydroxyhexyl)benzene-1,2-diol and (5S,8R)-6,7,8,9-tetrahydro-5-methyl-5·8-epoxy-5H-benzocycloheptene-2,3,4-triol. Interestingly, the production mechanism was deduced to be the inverse of the biosynthesis of the flavan-3-ol A ring.     

低剂量CT扫描技术在肺癌筛查中的应用价值

目的：探讨低剂量CT扫描技术在肺癌筛查中的应用价值。方法选取2013年5月~2014年5月240例于本院疑诊或确诊为肺癌的受检者240例,将其随机平均分为3组,均行胸部CT扫描。A组使用CARE Dose 4D技术,参考管电流设置为100 mAs,其余两组不使用CARE Dose 4D技术,管电流分别设置为100（B组）、50 mAs（C组）。比较3组的容积CT剂量指数（CTDIvol）、有效辐射剂量（ED）、图像噪声、图像质量评分及冠状动脉钙化灶数量。结果与 C组比较,A、B组的CTDIvol、ED明显增加,而其图像噪声、图像质量评分和钙化灶数量方面明显优于C组（P<0.05）;A组的CTDIvol、ED明显低于B组,但图像噪声、图像质量评分、钙化灶数量差异无统计学意义（P>0.05）。结论 CARE Dose 4D技术能够在保证CT诊断效果的基础上降低辐射剂量,值得推广。     

高危型人乳头瘤病毒基因分型聚合酶链式反应检测技术在宫颈癌筛查中的应用分析

目的 探讨以聚合酶链式反应(PCR)为基础的高危型人乳头瘤病毒(HPV)分型检测在宫颈癌筛查中的应用和诊断价值.方法 选取2016年6月至2019年6月西安航天医院收治的疑似宫颈病变病人628例,分别采取高危型HPV分型PCR技术(HR-HPV DNA PCR),液基薄层细胞学检查(TCT)以及病理组织活检诊断,以病理活检作为诊断宫颈病变的"金标准",分析高危型HPV感染与宫颈病变的关系以及高危型HPV分型检测技术在宫颈癌筛查中的应用价值.结果 HR-HPV DNA PCR技术的灵敏度为91.76％,特异度为91.29％,阳性预测值为9356％,阴性预测值为88.93％,符合率为91.56％,均显著优于TCT检测方法(P<0.001).同时,对13种HPV亚型分析发现,16、18亚型与宫颈癌及癌前病变密切相关(P<0.05),33、52及58型次之(P<0.05).而且,HPV的感染率随着年龄的增长而增长,>39～49岁病人HPV感染率为58.15％、>49～59岁病人为64.29％、>59岁病人为75.41％,均显著高于20～29岁的年轻病人的46.40％(P<0.05).结论 高危型HPV持续感染是宫颈癌及癌前病变发生的关键因素,以PCR为基础的高危型HPV分型检测在宫颈癌筛查中具有较高的应用价值.     

Rapid screening of glutathione-trapped reactive metabolites by linear ion trap mass spectrometry with isotope pattern-dependent scanning and postacquisition data mining

The present study describes a novel integrated approach for rapid analysis of reactive metabolites with a linear ion trap mass spectrometer (LTQ). In this approach, an isotope pattern-dependent scanning method was applied to the data acquisition of glutathione (GSH)-trapped reactive metabolites. Recorded full-scan MS and MS/MS data sets were further processed with neutral loss filtering, product ion filtering, and extracted ion chromatographic analysis to search for protonated molecules and MS/MS spectra of GSH adducts. To evaluate the effectiveness and reliability of the approach, GSH adducts of carbamazepine, diclofenac, 4-ethylphenol, acetaminophen, p-cresol, and omeprazole were analyzed, which were formed in human liver microsome incubations fortified with a mixture of nonlabeled GSH and stable isotope-labeled GSH at a 1:0.8 ratio. Results demonstrate that the combination of the isotope pattern-dependent scanning with the postacquisition data mining was very effective in detecting low levels of GSH adducts, regardless of their fragmentation patterns. As compared to a neutral loss scanning method performed with a triple quadrupole mass spectrometer, the LTQ-based approach had several major advantages, including the superior selectivity and sensitivity in detecting different classes of GSH adducts and the higher throughput capability of the detection and MS/MS spectral acquisition of GSH adducts in a single LC/MS run. Overall, this analytical approach provides a simple and efficient means for screening for reactive metabolites using a linear ion trap LC/MS platform.