罗汉松内生真菌的抑菌活性研究

为了研究药用植物内生真菌的次生代谢产物是否具有抑菌活性，以96株罗汉松内生真菌为研究材料，将菌丝及其培养液经氯仿-甲醇抽提后，采用杯碟法测定了全部菌株的抑菌活性。罗汉松内生真菌中49%的菌株具有抑菌作用，其中菌株LHS18、LHS42、LHS67、LHS92和LHS93抽提物经100倍稀释后对金黄色葡萄球菌仍有强的抑菌作用，菌株LHS30抽提物的100倍稀释溶液对大肠杆菌的生长有强烈的抑制作用。对抑菌活性较强的6株菌根据其ITS序列相似性进行了分子鉴定。菌株LHS18和LHS42鉴定为烟曲霉（Aspergillus fumigatus），LHS92为四孢脉孢菌（Neurospora tetrasperma），LHS30为丝枝霉（Aphanocladium sp.），LHS67为拟茎点霉（Phomopsis liquidambari），LHS93未能鉴定出种属。研究结果提示，罗汉松内生真菌中49%菌株具有抑菌活性，其中6株菌对动物和人类的病原菌有强列的抑制作用，是挖掘高效抑菌物质的重要资源。

Antibacterial Activity of Endophytic Fungi from Podocarpus macrophyllus

In order to study whether the secondary metabolites of endophytic fungi had antibacterial activity or not, 96 endophytes were isolated from P.macrophyllus in Guizhou province. The antibacterial activity of chloroform/methanol extracts of fermentation broth for 96 fungi was determined by cylinder plate method. 49% endophytic fungi from P.macrophyllus exhibited antibacterial activities against at least one bacterium among three pathogenic bacteria, Escherichia coli, Bacillus subtilis or Staphylococcus aureus. Out of the fungal endophytes isolated from P.macrophyllus, the extracts with 100 folds dilution of strain LHS18, LHS42, LHS67, LHS92 and LHS93 still displayed strong inhibitory activities against S.aureus and strain LHS30 against E.coli. Two strains, LHS18 and LHS42, were further identified to be Aspergillus fumigatus, LHS92 to be Neurospora tetrasperma, LHS30 to be Aphanocladium sp., LHS67 to be Phomopsis liquidambari, respectively. LHS93 was not identified for the low identity of internal transcribed spacer (ITS) sequence between rRNA genes with the known sequences of fungi in Nucleotide database. It suggested that 49% of the endophytic fungi isolated from P.macrophyllus showed potent antibacterial activity, which could be a resource for new antibiotics in future.