Destruxin A production by Metarhizium brunneum strains during transient endophytic colonisation of Solanum tuberosum

Metarhizium spp. are known to produce destruxin A (dtx A) and can act as endophytes. Data regarding the fate and behaviour of secondary metabolites in the environment are necessary for registration. Endophytic colonisation and dtx A production on potato plants were monitored at 24, 48, 72, 96 and 120?h after inoculation with Metarhizium brunneum strains (BIPESCO5 and EAMa 01/58-Su). Both strains were recovered from leaves, stem, tuber and root fragments of fungal-challenged potato plants. Although a similar colonisation was observed for both strains, there were differences in percentages in different parts of the plants, with the higher values occurring in the leaves at 96?h for EAMa 01/58-Su (83.3%) and BIPESCO5 (81.6%), and the lower ones, 10–13.3%, observed in tubers and roots at 72, 96 and 120?h post-inoculation for both strains. For strain EAMa 01/58-Su, dtx A was quantified at 24?h (2.49?±?1.7 and 2.0?±?1.4?µg/kg, respectively), and the same concentration was found in both tuber and root at 96?h (2.5?±?1.7?µg/kg); for BIPESCO5, the concentrations differed in tuber at 24?h and in root at 48?h (6.8?±?4.8 and 2.1?±?1.4?µg/kg, respectively). The concentration of dtx A in plant tissues was very low compared to the colonisation levels, suggesting that dtx A production by the fungus may be temporary and that the compound might degrade rapidly.     

泰国红树内生真菌土曲霉xy03菌株中新杂萜类成分

采用硅胶柱层析、SephadexLH-20凝胶柱层析和高效液相色谱(HPLC)等技术,从一株红树马六甲木果楝来源的土曲霉Aspergillus terreusxy03的发酵物中分离得到了7个杂萜类化合物:asptercin A(1)、(1R,4aR,6aR,12aR,12bS)-1,3,4,4a,5,6,6a,12,1...     

相似蜂海绵相关真菌杂色曲霉F62活性代谢产物研究

研究了1株相似蜂海绵相关真菌F62的活性代谢产物,经分子系统学分析表明该真菌属于杂色曲霉。将F62菌株用大米固体培养基在室温（约25℃）下静置培养45d,经乙酸乙酯超声萃取得到粗提物。通过硅胶柱层析、Sephadex LH-20凝胶柱层析和HPLC等色谱手段,分离得到了6个化合物。通过核磁共振、质谱等波谱分析手段可鉴定出其结构分别为Alantrypinone（1）、洛伐他汀（2）、甲酯型莫纳克林K（3）、土曲霉酮（4）、土震素B（5）和麦角甾醇（6）。化合物1系首次从该属真菌中分离得到,化合物2－5为首次从该种真菌中分离得到。首次对化合物3的碳谱数据进行报道。初步的药理研究表明,化合物4具有体外抗炎活性。     

Secondary metabolites produced by mangrove endophytic fungus Aspergillus fumigatus HQD24 with immunosuppressive activity

Immunosuppressive activity guided chemical investigation, four alkaloids (1–4) and eight polyketides (5–12) were isolated from mangrove-derived Aspergillus fumigatus HQD24. Their structures were elucidated unambiguously based on the comprehensive spectroscopic analysis and comparison with literature data. Compounds 1 and 3–5 were separated from mangrove endophytic fungi for the first time, 3 and 12 were firstly recovered from fungal genus Aspergillus. Compound 5 remarkable inhibited proliferation of ConA (concanavalin A)-induced T and LPS (lipopolysaccharide)-induced B murine spleen lymphocytes, with IC₅₀ of 12.11 ± 0.11 μM and 62.66 ± 0.80 μM, respectively. Meanwhile, the chemotaxonomic relations of isolated compounds and Aspergillus species were also discussed.     

The entomopathogen Beauveria bassiana has epiphytic and endophytic activity against the tomato leaf miner Tuta absoluta

The recent introduction and rapid spread of the tomato leaf miner Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) throughout Europe, Africa and the Middle East poses a severe threat to future cultivation of tomato and other Solanaceae. Among the best practicable means for effective and sustainable control of this invasive insect pest are entomopathogenic fungi, which can either prevent a further spread of this insect to new areas or keep population densities below an economic threshold level. Here, we report on the efficacy of a commercially available mycoinsecticide based on the entomopathogen Beauveria bassiana (Bals.) Vuill. (Ascomycota: Hypocreales) against all four larval stages of T. absoluta. In bioassays, high mortality rates and significantly reduced longevity of larvae were obvious when larvae had fed for a period of around 15 days on leaves with B. bassiana propagules present on the surface as an epiphyte with mortality values corrected for variance in control mortality of 90–100%. In addition, a second mode of action of B. bassiana against T. absoluta larvae was evident in bioassays in the form of an endophytic establishment of this fungus in treated tomato plants. Longevity of T. absoluta L4 larvae was significantly lower in individuals which had fed on surface‐sterilized tomato leaves obtained from plants treated 18 days before the bioassay with a B. bassiana suspension compared to larvae feeding on control plants treated with water. Corrected mortality reached values between 30% and 50% for all larval instars. Growth of tomato plants was not inhibited due to colonization by endophytic B. bassiana and a weak systemic translocation of fungal propagules in non‐treated leaves was evident in the assays. Accordingly, entomopathogenic fungi like B. bassiana express different modes of action again target insect pests, which is of particular relevance for the design of efficient management strategies for invasive pests like T. absoluta.     

抗肿瘤银杏内生真菌Aspergillus oryzae YX-5发酵 培养基的优化

【目的】对一株具有抗肿瘤活性的银杏内生真菌Aspergillus oryzae YX-5的发酵培养基进行优化。【方法】以发酵后的菌体干重、粗提物质量和粗提物抗肿瘤活性为指标,通过单因素实验选出合适的碳源和氮源,再以选出的碳源、氮源以及K2HPO4、MgSO4·7H2O、KCl共5个因素进行正交实验,确定出最适宜的发酵培养基配方。【结果】YX-5的最佳发酵培养基配方为葡萄糖45 g/L,蛋白胨8 g/L,K2HPO4 0.5 g/L,MgSO4·7H2O 0.2 g/L,KCl 1 g/L,FeSO40.01 g/L。优化后菌体干重、代谢物的产量和抗肿瘤活性分别提高了41.88%、226.52%和19.31%。【结论】通过对米曲霉菌(Aspergillus oryzae)YX-5的发酵培养基进行优化,明显提高了粗提物产量和抗肿瘤活性,这对后期规模化发酵中减小发酵规模和降低工作量十分有利。     

药用植物内生放线菌的生物活性及菌株D62的代谢产物分析

利用琼脂移块法及WST-8法分别对分离自西双版纳药用植物的165株内生放线菌进行了抗菌、抗肿瘤活性测定。结果显示,超过42%的菌株对病原菌表现出拮抗活性,且对病原真菌的总体拮抗活性明显强于土壤放线菌;78%的菌株表现出抗肿瘤活性,且大部分菌株(54.5%)具有强抗肿瘤活性。选取其中对真菌及肿瘤细胞均有高抑制活性的菌株D62,并对其次生代谢产物进行了进一步的研究,共分离得6个化合物,分别是Antimycin A4a(1),Antimycin A7a(2)、Antimycin A2a(3)、Antimycin A1a(4)、10-hydroxy-10-methyl-dodec-2-en-1,4-olide(5)及6-(2-(4-aminophenyl)-2-oxoethyl)-3,5-dimethyl-tetrahydropyran-2-one(6),其中化合物6为新化合物。以上结果表明药用植物内生放线菌作为一类新的微生物资源具有很好的开发潜力。     

Aspergillus fumigatus Fresenius, an endophytic fungus from Juniperus communis L. Horstmann as a novel source of the anticancer pro-drug deoxypodophyllotoxin

Aims:  Isolation, identification and characterization of an endophytic fungus from Juniperus communis L. Horstmann, as a novel producer of deoxypodophyllotoxin and its in vitro antimicrobial assay.
Methods and Results:  The methodology for the isolation, identification and characterization of a novel endophytic fungus from the twigs of the J. communis L. Horstmann plant, which specifically and consistently produces deoxypodophyllotoxin, was unequivocally established. The fungus was identified as Aspergillus fumigatus Fresenius by molecular, morphological and physiological methods. Deoxypodophyllotoxin was identified and quantified by high-resolution LC-MS, LC-MS² and LC-MS³. The antimicrobial efficacy of the fungal deoxypodophyllotoxin against a panel of pathogenic bacteria was established.
Conclusions:  The production of deoxypodophyllotoxin (found in the host) by the cultured endophyte is an enigmatic observation. It demonstrates the transfer of gene(s) for such accumulation by horizontal means from the host plant to its endophytic counterpart. It would be interesting to further study the deoxypodophyllotoxin production and regulation by the cultured endophyte in J.   communis and in axenic cultures.
Significance and Impact of the Study:  This endophyte is a potential handle for scientific and commercial exploitation. Although the current accumulation of deoxypodophyllotoxin by the endophyte is not very high, it could be scaled-up to provide adequate production to satisfy new drug development and clinical needs. However, further refined precursor-feeding and mass-balance studies are required to result in the consistent and dependable production.     

HPLC法检测蛇足石杉内生真菌胶胞炭疽发酵液中石杉碱甲和石杉碱乙的含量

建立了高效液相色谱(HPLC)测定蛇足石杉(Huperzia serrate)内生真菌胶胞炭疽发酵液中石杉碱甲(Huperzina A)和石杉碱乙(Huperzine B)含量的方法,并以此方法检测胶胞炭疽发酵液中石杉碱甲和石杉碱乙含量的积累。内生真菌发酵液经氯仿萃取、甲醇溶解、过滤后进行高效液相检测分析,选用Agilent Eclipse plus-C18色谱柱(250 mm×4.6 mm,5μm),以0.015 mol/L乙酸铵(p H 6.8)和甲醇溶液(70∶30)为流动相进行等度洗脱,流速1 mL/min,检测波长为308 nm,连续检测内生真菌胶胞炭疽发酵液中第6–15天石杉碱甲和石杉碱乙的含量积累。结果表明,发酵提取液中的石杉碱甲和石杉碱乙可在25 min内进行很好的分离和分析,石杉碱甲在1.50-48.00μg/mL范围内线性关系良好(相关系数r为0.999 5),石杉碱乙在0.25-7.50μg/mL范围内线性关系良好(相关系数r为0.999 7),石杉碱甲和石杉碱乙的平均加标回收率分别为106.83%、108.06%,相对标准偏差(RSD)分别为3.34%、3.60%。该方法简便、快速、精密度高、结果准确,适用于内生真菌发酵液中石杉碱甲和石杉碱乙含量检测。在发酵过程中,内生真菌发酵液中石杉碱甲和石杉碱乙的含量呈现先增后减,随后有所增加继而又减少的趋势。石杉碱甲和石杉碱乙的含量分别在内生真菌发酵第14天、第8天达到最高,分别为12.417 0μg/mL、4.660 3μg/mL。该方法学的建立为内生真菌胶胞炭疽合成石杉碱甲与石杉碱乙的机制研究提供了检测手段,从而有利于药物新资源的开发。     

红树林内生真菌研究进展

红树林作为一种特殊的植物群落具有丰富的内生真菌资源,目前已分离鉴定的红树林真菌超过200种,成为海洋真菌的第二大类群,已报道的红树林内生真菌主要类群是链格孢霉(Alternaria)、曲霉(Aspergillus)、芽枝霉(Cladosporium)、炭疽菌(Colletotrichum)、镰孢霉(Fusarium)、拟青霉(Paecilomyces)、拟盘多毛孢(Pestalotiopsis)、青霉(Penicillium)、茎点霉(Phoma)、拟茎点霉(Phomopsis)、叶点霉(Phyllosticta)和木霉(Trichoderma)等.大部分红树林内生真菌具有较宽的宿主范围,极少数只有单一的宿主,不同红树林植物的内生真菌区系及优势种群有很大差异.红树林内生真菌的定殖因宿主植物不同部位、植株的年龄及季节和环境的变化明显不同.红树林内生真菌能产生多种代谢产物,具有抗菌、抗肿瘤等药用价值.红树林植物内生真菌的研究和开发具有重要意义.本文综述了红树林内生真菌的生物多样性及其分布、生物学功能和次生代谢产物等方面的研究进展.     

地衣及其内生真菌活性次级代谢产物研究进展

地衣是一种独特的菌藻共生体,能够在荒漠、高山、冻土等恶劣环境生存,具有特殊的生理结构和独特的生存环境.地衣及其内生真菌能够产生结构新颖、活性广泛的次级代谢产物,研究地衣及其内生真菌次级代谢产物对新型药用资源开发以及利用等方面都具有重要的意义.本文关注了近年来地衣及其内生真菌的次级代谢产物相关研究,并对其生物活性方面的研...     

药用植物内生真菌的多样性及生物功能研究进展

药用植物内生真菌资源丰富,其代谢产物常具有抗肿瘤、抗氧化、抑菌等作用,能产生药用植物生长调节物质及与宿主相同或类似的次生代谢产物,从而成为近年来的研究热点。本文对药用植物内生真菌的分离鉴定、多样性、生物活性及生物学功能等方面进行综述,以期为今后筛选及利用有效的药用植物内生真菌奠定基础。     

一株具有抗疟活性的金鸡纳树内生真菌的研究

为筛选具抗疟疾活性的的内生真菌,采用平板分离法对海南金鸡那树内生真菌进行分离纯化。利用"4日抑制疟疾"测试内生真菌发酵液的抗疟活性,采用TLC、HPLC等分析技术对内生菌发酵液等成分进行分析。从金鸡那树叶片分离到31种内生真菌,通过筛选找到了1株具有抗疟疾活性的产奎宁或奎宁类似物的内生真菌。从金鸡那树叶片中分离得到1株产奎宁的结实串孢霉属内生真菌,为奎宁的资源开发开辟了新途径。     

An endophytic taxol-producing fungus from Taxus x media, Aspergillus candidus MD3

An endophytic taxol-producing fungus (strain MD3) isolated from the inner bark of Taxus x media was identified as Aspergillus candidus according to its morphological characteristics, physiological and biochemical characteristics, and 18S rRNA gene sequence analysis. Taxol produced by A. candidus MD3 was shown to be identical to authentic taxol analyzed by UV, HPLC, MS and nuclear magnetic resonance spectroscopy. The gene encoding the 10-deacetylbaccatin III-10- O -acetyl transferase, which catalyzes formation of the last diterpene intermediate in the taxol biosynthetic pathway, has been cloned from A. candidus MD3 for the first time and possesses high homology to the same gene found in Taxus spp.     

蒜头果内生真菌次生代谢产物抑制人类致病菌活性的研究

蒜头果是我国特有的单种属稀有树种,为了进一步开发利用蒜头果树皮内生真菌的抗菌活性化合物,该研究对来自蒜头果的植物内生真菌(白黄笋顶孢霉、哈茨木霉、大棘黑团孢、枝状枝孢菌、斑污拟盘多毛孢、赭绿青霉、淡紫紫孢菌、朱黄青霉、Xenoacremonium recifei、Xylaria feejeensis)进行液体培养,10 d后回收培养液并用乙酸乙酯萃取获得初提物,采用抑菌圈法检测蒜头果内生真菌初提物抑菌活性,同时测定了最低抑菌浓度(MIC)。结果表明:白黄笋顶孢霉、大棘黑团孢、枝状枝孢菌、斑污拟盘多毛孢、赭绿青霉、淡紫紫孢菌均有抑菌活性,大棘黑团孢、斑污拟盘多毛孢、淡紫紫孢菌的初提物均对缓慢芽孢杆菌、无乳链球菌和藤黄微球菌有明显抗菌活性,最低抑菌浓度在1.562 5~6.25 mg·m L~(-1)之间。这说明蒜头果树皮内生真菌的次生代谢产物具有抗菌活性,各内生真菌次生代谢产物的抗菌效果不同。     

Differential impact of some Aspergillus species on Meloidogyne javanica biocontrol by Pseudomonas fluorescens strain CHA0

AIMS: The aim was to determine the influence of some Aspergillus species on the production of nematicidal agent(s) in vitro and biocontrol of Meloidogyne javanica in tomato by Pseudomonas fluorescens strains CHA0 and CHA0/pME3424. METHODS AND RESULTS: Six species of Aspergillus, isolated from the rhizosphere of certain crops, produced a variety of secondary metabolites in vitro. Culture filtrate (CF) obtained from Ps. fluorescens strain CHA0 and its2,4-diacetylphloroglucinol overproducing mutant CHA0/pME3424 grown in King's B liquid medium caused significant mortality of M. javanica juveniles in vitro. Bacterial growth medium amended with CF of A. niger enhanced nematicidal and beta-galactosidase activities of fluorescent pseudomonads while A. quadrilineatus repressed such activities. Methanol or ethyl acetate extracts of the CF of A. niger markedly optimized bacterial efficacy to cause nematode deaths while hexane extract of the fungus had no influence on the nematicidal activity of the bacterial strains. A. niger applied alone or in conjunction with the bacterial inoculants inhibited root-knot nematode galling in tomato. On the other hand, A. quadrilineatus used alone or together with CHA0 did not inhibit nematode galling but when used in combination with strain CHA0/pME3424 did reduce galling intensity. CONCLUSIONS: Aspergillus niger enhances the production of nematicidal compounds by Ps. fluorescensin vitro and improves biocontrol potential of the bacterial inoculants in tomato while A. quadrilineatus reduces bacterial performance to suppress root-knot nematodes. SIGNIFICANCE AND IMPACT OF THE STUDY: Rhizosphere harbours a variety of micro-organisms including bacteria, fungi and viruses. Aspergillus species are ubiquitous in most agricultural soils and generally produce a variety of secondary metabolites. Such metabolites synthesized by Aspergillus species may influence the production of nematicidal agents and subsequent biocontrol performance of the bacterial inoculants against plant-parasitic nematodes. This fact needs to be taken into consideration when using biocontrol strains in an agriculture system.     

植物内生拟盘多毛孢的生物多样性

内生拟盘多毛孢是植物 (尤其是木本植物 )内生真菌的重要类群。分离自红豆杉的内生小孢拟盘多毛孢(Pestalotiopsismicrospora)能产生抗癌的代谢产物紫杉醇 ,因而引起了人们对内生拟盘多毛孢研究的兴趣。拟盘多毛孢内生于植物的根、茎、叶及繁殖体中 ,已鉴定的内生拟盘多毛孢有 2 3种。在已调查的植物中 ,内生拟盘多毛孢的定殖率有很大差异 ,在红树 (Rhizophoraapiculata)、椰子 (Cocosnucifer)、西藏红豆杉 (Taxuswallichiana)、茶梅 (Camelliasasanqua)、Fragraeabodenii和Cordemoyaintegrifolia等木本植物中 ,拟盘多毛孢是内生真菌的优势类群。一种拟盘多毛孢可内生于多种植物体内 ,一种植物也可有多种拟盘多毛孢内生 ,其分布与植物所处的生态环境和地域有关。在一定的宿主植物生理条件或外界环境条件下 ,某些内生拟盘多毛孢可转变为寄生或腐生。对植物内生拟盘多毛孢代谢产物的研究表明 ,拟盘多毛孢可产生多种次生代谢产物 ,包括抗癌物质 (紫杉醇和粗榧酸 )和抗菌物质 (环己烷类物质、粗榧酸和 pestaloside)。植物内生拟盘多毛孢的资源调查和开发应用具有广阔的前景。