| Cordyceps s.1.is a large and special group of fungi belonging to Ascomycota,Sordariomycetes,Hypocreales.Cordyceps s.1.includes all species of Cordycipitaceae,Ophiocordycipitaceae,Polycephalomycetaceae and some species of Clavicipitaceae.Research on the secondary metabolites,taxonomy,biological activity,and health advantages of Cordyceps s.l.has increased significantly in recent years.During the field investigation of macrofungi in Zhejiang Province,we collected two cordycepioides species.This study revolves around two species,including taxonomic study of them,the antimicrobial activity of crude extracts of fermented mycelium of it against food-borne pathogenic bacteria,and the separation and identification of secondary metabolites from Blackwellomyces kaihuaensis.The following are the key findings:1.Identification of two new species by phylogenetic analysis of five gene fragments(nrSSU,nrLSU,tef1,rpb1,rpb2)and morphological studies.Morphological characteristics for Blackwellomyces kaihuaensis:Stromata single or multiple,6-12 × 0.8-1.2 mm,orange red to bright red,cylindrical to clavate.Fertile part bright reddish orange,clavate or palmated,1.5-4 × 1.0-1.6 mm.Perithecia semi-immersed,narrowly ovoid,(280)320-370(410)×(100)120-180(200)μm.Asci cylindrical,(140)170-240(270)×3.5-4.5 μm.Ascospores filiform,hyaline,irregularly multiseptate,(130)160-220(250)×1.0-1.5 μm,do not separate into part-spores when they reach maturity.Morphological characteristics for Metarhizium putuoense:Stromata single or multiple,25-60×2-4 mm,pale yellow to light brown,usually clavate.Fertile part light brown to pale purple,clavate or irregularly shaped,10-15×2-4 mm,the top is purple and infertility.Perithecia immersed,narrowly ovoid,(420)450-500(530)×(220)250-300(330)μm.Asci cylindrical,(190)210-260(280)×5-7 μm,Ascospores filiform,hyaline,irregularly multiseptate,(170)190-240(260)×1.0-1.5 μm,do not separate into partspores when they reach maturity.2.The antagonistic effects of mycelium extract from two entomogenous fungal on 13 food-borne pathogen strains were different,especially the methanol and ethanol extracts,which showed stronger antibacterial properties.The crude extracts of ethyl acetate and water also showed some antibacterial activity while the crude extract of petroleum ether without antibacterial activity.MIC of methanol extracts from B.kaihuaensis against Staphylococcus aureus(CICC 21600),Escherichia coli(CICC 10664)and Vibrio alginolyticus(CICC 10889)was 2.50 mg/mL,5.00 mg/mL and 1.25 mg/mL,the inhibitory rates were 91.3%,83.2%,92.7%;MIC of ethanol extracts from B.kaihuaensis against Staphylococcus aureus(CICC 21600),Escherichia coli(CICC 10664)and Vibrio alginolyticus(CICC 10889)was 1.25 mg/mL,2.50 mg/mL and 2.50 mg/mL,the inhibitory rates were 91.9%,86.1%,91.4%.MIC of methanol extracts from M.putuoense against Bacillus cereus(CICC 21261),Vibrio minimus(CICC 21613)and Escherichia coli(CICC 10664)was 7.50 mg/mL,3.75 mg/mL,3.75 mg/mL,the inhibitory rates were 88.1%,92.5%,90.5%;MIC of ethanol extracts from M putuoense against Bacillus cereus(CICC 21261),Vibrio minimus(CICC 21613)and Escherichia coli(CICC 10664)was 3.75 mg/mL,1.88 mg/mL,3.75 mg/mL,the inhibitory rates were 91.3%,91.7%,87.4%.3.The chemical composition of the secondary metabolites from B.kaihuaensis was studied,21 fractions were initially isolated from the crude extract of ethyl acetate.Three cyclic peptides were separated with dextran gel column and semi-preparative HPLC,which were identified as Cardinalisamides A-C by NMR and literature comparisons.This study was an important supplement to the diversity of Cordyceps s.l.resources in Zhejiang Province,it provided new material for the resource protection of entomogenous fungal and other fields.It offered an experimental basis and theoretical basis for antimicrobial research in food-related fields.It has enriched the research related to secondary metabolites of Cordyceps s.l.and laid the corresponding foundation for its rationalization research and development. |
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