贵州兴义喀斯特洞穴可培养放线菌多样性及抗菌活性初筛

【目的】进一步了解兴义喀斯特洞穴可培养放线菌资源及产活性代谢产物的能力。【方法】选取多种分离培养基,利用稀释直接涂布平板法对贵州黔西南兴义市多个喀斯特洞穴的土壤和岩石进行可培养放线菌资源分离;利用三种发酵培养基对相关放线菌进行生物产物初筛。【结果】根据16S rRNA基因序列的比对分析,将分离得到的251株放线菌分别归类到44个属,其中链霉菌属(Streptomyces)占分离菌株的比例为24.30%,小单孢菌属(Micromonospora)占比11.95%,红球菌属(Rhodococcus)占比9.16%,微杆菌属(Microbacterium)占比7.17%,诺卡氏菌属(Nocardia)占比6.37%,该五类放线菌为该地区可培养放线菌的优势菌群。对70株细菌进行活性次级代谢产物筛选,其中35株放线菌对指示菌具有抑制活性,且主要类群为链霉菌属和小单孢菌属。【结论】贵州兴义喀斯特洞穴中存在丰富多样的放线菌类群,且蕴藏大量具有产生活性次级代谢产物能力的菌株,为医药产业提供潜力菌株资源,极具进一步发掘和研究的价值。     

百部内生放线菌的分离、分类及次级代谢潜力

【目的】以对叶百部块根为材料分离内生放线菌,并对分离菌株进行分类、抗菌活性和次级代谢产物合成基因研究。【方法】样品经过严格的表面消毒,选用4种培养基分离百部内生放线菌;分离菌株通过形态观察和16S rRNA序列分析进行分类鉴定;采用琼脂移块法测试分离菌株的抗菌活性;通过PCR检测分离菌株的PKS/NPRS和卤化酶基因;使用HPLC-UV/VIS-ESI-MS/MS分析发酵产物。【结果】从6个样品中获得18株内生放线菌,分属链霉菌属(Streptomyces)、小单孢菌属(Micromonospora)、假诺卡氏菌属(Pseudonocardia)和甲基杆菌属(Methylobacterium)。分离菌株绝大部分具有抗菌活性和次级代谢产物合成基因,其中13株对耐药金黄色葡萄球菌和/或绿脓杆菌有拮抗活性,17株具有PKS/NRPS基因,8株菌具有卤化酶基因,且卤化酶阳性代表菌株的发酵产物具有抗细菌活性和卤代化合物特征。【结论】百部作为一种传统中药,其内生放线菌以链霉菌和小单孢菌为主,在次级代谢产物合成方面具有很好的潜力,可作为一类重要微生物资源进行活性产物开发。     

小球腔菌属次级代谢产物的化学及其生物学活性研究进展

小球腔菌可引发油菜黑胫病等给农业造成严重的经济损失。该属真菌的次级代谢产物研究开始较早,化合物分离工作主要围绕黑胫病致病菌株,研究发现该属真菌的次级代谢产物十分丰富,许多化学结构新颖、具有显著生物活性的化合物均被发现。为使该属的真菌资源得到充分的开发与利用,本文对40多年来报道的小球腔菌属次级代谢产物的化学及其生物学活性进行了较为全面的综述。     

永兴岛白穗软珊瑚共附生放线菌筛选及部分活性次级代谢产物的鉴定

【目的】从白穗软珊瑚中分离和鉴定共附生放线菌,运用PCR技术对所分离的放线菌进行I型聚酮合酶(PKS)筛选,研究其次级代谢产物。【方法】使用11种培养基对白穗软珊瑚共附生放线菌进行分离、鉴定,构建16S rRNA基因系统发育进化树,以基于I型PKS的KS基因设计的简并引物对所分离放线菌进行基因筛选,对阳性菌株用3种培养基发酵检测,对目标菌株进行放大规模发酵分离鉴定次级代谢产物。【结果】从白穗软珊瑚中分离到20株共附生放线菌,包括链霉菌属10株、迪茨氏菌属2株和盐水孢菌属8株,筛选获得18株I型PKS阳性菌株,并从菌株Salinospora arenicola SH04中分离到化合物rifamycin S和rifamycin W。【结论】首次从珊瑚共附生环境中分离得到海洋专属性稀有放线菌盐水孢菌属,并以I型PKS基因筛选为指导,分离鉴定了聚酮类化合物rifamycins,为研究软珊瑚共附生可培养放线菌的多样性和基于基因筛选指导分离次级代谢产物提供了可靠依据。     

湛江高桥红树林沉积物放线菌多样性及其中一株链霉菌产生的germicidins类化合物的鉴定

【目的】从3种红树林植物根际沉积物中分离和鉴定放线菌,进行抑菌活性初筛获得目标菌株并研究其次级代谢产物。【方法】使用5种培养基对红树林植物根际沉积物放线菌进行分离,采用16S rRNA基因序列比对的方法研究沉积物中的放线菌多样性,结合抑菌活性筛选获得目标菌株后进行放大规模发酵和分离鉴定次级代谢产物,根据生物合成基因簇定位和分析对化合物的生物合成途径进行推导。【结果】从3种红树林植物根际沉积物中分离得到放线菌49株,包括链霉菌属(Streptomyces)31株、小单孢菌属(Micromonospora)14株、小双孢菌属(Microbispora)、链孢子囊菌属(Streptosporangium)、野野村氏菌属(Nonomuraea)和糖单孢菌属(Saccharomonospora)各1株。获得粗浸膏抑菌活性较好的菌株Streptomyces sp. SCSIO 40067,从中分离鉴定了6个α-吡喃酮类化合物：germicidin A–C、germicidin I和isogermicidin A–B,并首次报道了germicidin A的晶体结构。从菌株SCSIO 40067基因组...     

塔里木盆地胀果甘草内生放线菌多样性及抗菌活性分析

【目的】发掘具有开发前景的放线菌资源,对分离自新疆胀果甘草的内生放线菌的多样性、抗菌活性和次级代谢产物合成相关基因进行研究。【方法】采用5种培养基和3种前处理方法,从胀果甘草中分离获得80株放线菌。基于菌株形态学特征,对36株代表菌株进行抗菌活性检测,通过特异性引物扩增方法,检测了PKS I、PKS II、NPRS和卤化酶基因,探究其合成天然产物的潜在能力。结合筛选结果,选取其中20株代表菌,经16S r RNA基因测序,对其进行系统发育分析。【结果】培养基E2和E3结合热处理的分离效果较好;86.1%的代表菌株对供试的细菌、病原真菌表现出了不同程度的抗菌活性,PKS I、PKS II、NRPS基因和卤化酶基因阳性检出率分别为16.7%、72.2%、25.0%和11.1%。具有活性功能的代表菌株经16S r RNA基因测序分析,分别属于链霉菌属(Streptomyces)、小单胞菌属(Micromonospora)、红球菌属(Rhodococcus)和游动放线菌属(Actinoplanes)4个属,其中链霉菌属(Streptomyces)为优势菌属,占60%以上。【结论】胀果甘草是我国传统的药用植物,其植株内部蕴藏着丰富的放线菌资源,并在次生代谢产物合成方面拥有巨大潜力,具有进一步开发的价值。     

肇庆星湖湿地可培养放线菌多样性

摘要:【目的】探究星湖湿地可培养放线菌物种多样性,筛选潜在药源活性代谢产物产生菌,为后续菌种资源开发奠定基础。【方法】采用5种选择性分离培养基分离星湖湿地底泥中的放线菌,通过16S rRNA基因同源性分析代表性菌株的物种多样性;以3株病原细菌为指示菌检测分离菌株的抑菌活性;PCR扩增代表菌株的聚酮合酶(PKS I、PKS II)基因、非核糖体多肽合成酶(NRPS)基因、安莎类化合物(AHBA)基因及3-羟基-3-甲基戊二酰辅酶A还原酶(HMGA)基因。【结果】分离到135株放线菌菌株,被鉴定为放线菌纲的7 个目、10个科、13个属,优势类群为链霉菌、小单孢菌及诺卡氏菌。83株检测菌中,24.09%抗金黄色葡萄球菌(Staphylococcus aureus),4.8%抗大肠杆菌(Escherichia coli);24株高活性菌株中PKS I阳性率16.7%,PKS II阳性率62.5%,NRPS阳性率16.7%,AHBA阳性率12.5%,HMGA阳性率29.2%。活性复筛及HPLC结果显示,菌株XD007、XD114和XD128显著抑制3株病原指示菌,且能产生大量次级代谢产物。【结论】星湖湿地底泥中放线菌资源丰富,筛选到的活性菌株可用于后续药源活性次级代谢产物的分离。     

海洋放线菌Marinactinospora thermotolerans的研究进展

海洋放线菌以产生多种活性天然产物而著称,其中部分结构新颖的活性化合物具有发展成为新药的巨大潜力,引起国内外相关领域研究人员的极大关注。同时,也促进了我国海洋放线菌研究工作的全面展开。本文系统综述了海洋放线菌新属种Marinactinospora thermotolerans的分类鉴定、新颖的次级代谢产物的发现及其生物合成机制以及该菌株的全基因组生物信息学分析等方面的最新研究进展,以期能为其他海洋放线菌新属种的分类鉴定、活性次级代谢产物的发现和生物合成机制研究提供借鉴作用。     

无定形孢囊菌属中的一个新种

从我国云南省的土壤中分离出一株放线菌(B133号菌株),该菌株无气丝,基丝侧枝顶端或孢囊梗上形成裂叶状、掌状或棒状的孢囊,细胞壁组扮Ⅱ型。根据这些特征,此菌株应属于游动放线菌科中的无定形孢囊菌属。它与该属的已知种比较均有显著差别,因此认为是一新种,定名为栗色无定形孢囊菌(Amorphosporangium castaneum n. sp.)。     

热带药用植物根际放线菌的分离、鉴定及生物活性分析

从海南热带植物园采集12种药用植物的根际土样,采用选择性分离方法,分离得到400株根际放线菌。使用5种活性筛选模型对分离菌株进行生物活性评价,154株放线菌在一个或多个活性筛选模型中显示为阳性,菌株初筛阳性率达38.5%;根据菌株形态特征并结合代谢产物的生物活性,从中挑选出28株菌进行16S rRNA基因序列分析,发现其分属于链霉菌属、诺卡氏菌属、小单孢菌属和野野村菌属。     

Biologically active secondary metabolites from Actinomycetes

Secondary metabolites obtained from Actinomycetales provide a potential source of many novel compounds with antibacterial, antitumour, antifungal, antiviral, antiparasitic and other properties. The majority of these compounds are widely used as medicines for combating multidrug-resistant Gram-positive and Gram-negative bacterial strains. Members of the genus Streptomyces are profile producers of previously-known secondary metabolites. Actinomycetes have been isolated from terrestrial soils, from the rhizospheres of plant roots, and recently from marine sediments. This review demonstrates the diversity of secondary metabolites produced by actinomycete strains with respect to their chemical structure, biological activity and origin. On the basis of this diversity, this review concludes that the discovery of new bioactive compounds will continue to pose a great challenge for scientists.     

Biosynthesis of secondary metabolites in the rice blast fungus Magnaporthe grisea: the role of hybrid PKS-NRPS in pathogenicity

Fungal secondary metabolites are an important source of bioactive compounds for agrochemistry and pharmacology. Over the past decade, many studies have been undertaken to characterize the biosynthetic pathways of fungal secondary metabolites. This effort has led to the discovery of new compounds, gene clusters, and key enzymes, and has been greatly supported by the recent releases of fungal genome sequences. In this review, we present results from a search for genes involved in secondary metabolism and their clusters in the genome of the rice pathogen, Magnaporthe grisea, as well as in other fungal genomes. We have also performed a phylogenetic analysis of recently discovered genes encoding hybrids between a polyketide synthase and a single non-ribosomal peptide synthetase module (PKS–NRPS), as M. grisea seems rich in these enzymes compared with other fungi. Using results from expression and functional studies, we discuss the role of these PKS-NRPS in the avirulence and pathogenicity of M. grisea.     

Streptomyces associated with a marine sponge Haliclona sp.; biosynthetic genes for secondary metabolites and products

Terrestrial actinobacteria have served as a primary source of bioactive compounds; however, a rapid decrease in the discovery of new compounds strongly necessitates new investigational approaches. One approach is the screening of actinobacteria from marine habitats, especially the members of the genus Streptomyces. Presence of this genus in a marine sponge, Haliclona sp., was investigated using culture‐dependent and ‐independent techniques. 16S rRNA gene clone library analysis showed the presence of diverse Streptomyces in the sponge sample. In addition to the dominant genus Streptomyces, members of six different genera were isolated using four different media. Five phylogenetically new strains, each representing a novel species in the genus Streptomyces were also isolated. Polyphasic study suggesting the classification of two of these strains as novel species is presented. Searching the strains for the production of novel compounds and the presence of biosynthetic genes for secondary metabolites revealed seven novel compounds and biosynthetic genes with unique sequences. In these compounds, JBIR‐43 exhibited cytotoxic activity against cancer cell lines. JBIR‐34 and ‐35 were particularly interesting because of their unique chemical skeleton. To our knowledge, this is the first comprehensive study detailing the isolation of actinobacteria from a marine sponge and novel secondary metabolites from these strains.     

Taxonomy and secondary metabolites of <Emphasis Type="Italic">Pseudobotrytis</Emphasis> sp. FKA-25

Fungal strain FKA-25, isolated from forest soil collected on Yakushima Island, Kagoshima Prefecture, Japan, was assigned to genus Pseudobotrytis based on its morphological characteristics. Conidiophores were erect, slightly swollen at the end of the tip, and gave rise to umbellate conidiogenous cells that were in an expanded denticulate portion at the end and formed ellipsoidal to clavate conidia in sympodial succession. Identification as species P. terrestris was made on the basis of the character of 1-septate conidium. Although no secondary metabolites have been reported from the genus Pseudobotrytis, four secondary metabolite compounds (designated A to D) were isolated from the culture broth of strain FKA-25. Compounds B to D have been reported previously as FK-17-p2a, lunatinin, and 3,4-dihydro-3,4,8-trihydroxy-1(2H)-naphthalenone, respectively. Compound A was designated sespendole and possessed a novel indole-sesquiterpene skeleton.     

Metabolomic Profile of the Genus Inula

Plants have a long history as therapeutics in the treatment of human diseases and have been used as source of medicines for ages. Searching for new biologically active natural products, many plants and herbs are screened for natural products with pharmacological activities. In this field, the genus Inula, which comprises more than 100 species, several of them being used in traditional medicine, is very important, especially due to the finding that several of the isolated pure secondary metabolites proved to possess important biological activities. Inula species have been reported as rich sources of sesquiterpene lactones, including eudesmanes, germacranes, guaianes, and dimeric structures, and since 2006 ca. 400 secondary metabolites, including more than 100 new natural products, some of them with relevant pharmacological activities, have been identified. Herein, we critically compile and update the information regarding the types of secondary metabolites found in the genus Inula and the progress in their isolation.     

<Emphasis Type="Italic">Penicillium svalbardense</Emphasis>, a new species from Arctic glacial ice

During investigations of mycobiota in the coastal Arctic polythermal glaciers, different species of the ubiquitous genus Penicillium were isolated from the extreme subglacial environment. A group of Penicillium strains was obtained that did not belong to any known Penicillium species. This species was isolated in high numbers from the Kongsvegen subglacial ice and was not detected in the surrounding environment. A detailed analysis of secondary metabolite profiles, physiological and morphological characteristics, and partial β-tubulin gene sequences showed that the proposed new species Penicillium svalbardense is closely related but not identical to Penicillium piscarium and Penicillium simplicissimum. It differs in the production of secondary metabolites and in the morphological features of conidia and penicilli, and it is therefore described as a new species.     

绿针假单胞菌的研究进展及农业应用潜力

绿针假单胞菌(Pseudomonas chlororaphis)是目前研究较多的生防菌种之一.19世纪初被Miguela首次分离,将其鉴定为假单胞菌(Pseudomonas),并将机会性病原菌绿脓杆菌作为其模式菌株,而后Peix于2007年重新将其分类为绿针假单胞菌(P.chlororaphis).目前该菌种已报道有4...     

The genus <Emphasis Type="Italic">Diaporthe</Emphasis>: a rich source of diverse and bioactive metabolites

The genus Diaporthe (asexual state: Phomopsis) comprises pathogenic, endophytic and saprobic species with both temperate and tropical distributions. Although species of Diaporthe have in the past chiefly been distinguished based on host association, studies have confirmed several taxa to have wide host ranges, suggesting that they move freely between hosts, frequently co-colonizing diseased or dead tissue, while some species are known to be host-specific. They are also very frequently isolated as endophytes of seed plants. Due to their importance as plant pathogens, the genus has been thoroughly investigated for secondary metabolites, including during screening programs aimed at the discovery of novel bioactive natural products, but the respective information has never been compiled. Therefore, we have examined the relevant literature to explore and highlight the major classes of metabolites of Diaporthe and their Phomopsis conidial states. These fungi predominantly produce a large number of polyketides, but cytochalasins and other types of commonly encountered fungal secondary metabolites are also predominant in some species. Interestingly, not a single metabolite which is also known from the host plant has ever been isolated as a major component from an endophytic Diaporthe strain, despite the fact that many of the recent studies were targeting endophytic fungi of medicinal plants.     

Penicillium Mycobiota in Arctic Subglacial Ice

Fungi have been only rarely isolated from glacial ice in extremely cold polar regions and were in these cases considered as random, long-term preserved Aeolian deposits. Fungal presence has so far not been investigated in polar subglacial ice, a recently discovered extreme habitat reported to be inhabited exclusively by heterotrophic bacteria. In this study we report on the very high occurrence (up to 9000 CFU L⁻¹) and diversity of filamentous Penicillium spp. in the sediment-rich subglacial ice of three different polythermal Arctic glaciers (Svalbard, Norway). The dominant species was P. crustosum, representing on the average half of all isolated strains from all three glaciers. The other most frequently isolated species were P. bialowiezense, P. chrysogenum, P. thomii, P. solitum, P. palitans, P. echinulatum, P. polonicum, P. commune, P. discolor, P. expansum, and new Penicillium species (sp. 1). Twelve more Penicillium species were occasionally isolated. The fungi isolated produced consistent profiles of secondary metabolites, not different from the same Penicillium species from other habitats. This is the first report on the presence of large populations of Penicillium spp. in subglacial sediment-rich ice.     

The use of secondary metabolite profiling in chemotaxonomy of filamentous fungi

A secondary metabolite is a chemical compound produced by a limited number of fungal species in a genus, an order, or even phylum. A profile of secondary metabolites consists of all the different compounds a fungus can produce on a given substratum and includes toxins, antibiotics and other outward-directed compounds. Chemotaxonomy is traditionally restricted to comprise fatty acids, proteins, carbohydrates, or secondary metabolites, but has sometimes been defined so broadly that it also includes DNA sequences. It is not yet possible to use secondary metabolites in phylogeny, because of the inconsistent distribution throughout the fungal kingdom. However, this is the very quality that makes secondary metabolites so useful in classification and identification. Four groups of organisms are particularly good producers of secondary metabolites: plants, fungi, lichen fungi, and actinomycetes, whereas yeasts, protozoa, and animals are less efficient producers. Therefore, secondary metabolites have mostly been used in plant and fungal taxonomy, whereas chemotaxonomy has been neglected in bacteriology. Lichen chemotaxonomy has been based on few biosynthetic families (chemosyndromes), whereas filamentous fungi have been analysed for a wide array of terpenes, polyketides, non-ribosomal peptides, and combinations of these. Fungal chemotaxonomy based on secondary metabolites has been used successfully in large ascomycete genera such as Alternaria, Aspergillus, Fusarium, Hypoxylon, Penicillium, Stachybotrys, Xylaria and in few basidiomycete genera, but not in Zygomycota and Chytridiomycota.