Journal Article Antimicrobial properties and the influence of temperature on secondary metabolite production in cold environment soil fungi

14pp.60 - 67 , 2017-12
ISSN:18739652
Description
The Arctic and Antarctic share environmental extremes. To survive in such environments, microbes such as soil fungi need to compete with or protect themselves effectively from other soil microbiota and to obtain the often scarce nutrients available, and many use secondary metabolites to facilitate this. We therefore (i) screened for antimicrobial properties of cold-environment Arctic and Antarctic soil fungi, and (ii) identified changes in the secreted secondary metabolite profiles of a subset of these strains in response to temperature variation. A total of 40 polar soil fungal strains from King George Island, maritime Antarctic and Hornsund, Svalbard, High Arctic, were obtained from the Malaysian National Antarctic Research Centre culture collections. The plug assay technique was used to screen for antimicrobial potential against Gram-positive and Gram-negative human pathogenic bacteria (Bacillus subtilis, B. cereus, Pseudomonas aeruginosa, Enterococcus faecalis and Escherichia coli). About 45% of the tested fungal strains showed antimicrobial activity against at least one tested microorganism. Three fungal isolates showed good bioactivity and were subjected to secondary metabolite profiling at different temperatures (4, 10, 15 and 28 °C). We observed a range of responses in fungal metabolite production when incubated at varying temperatures, confirming an influence of environmental conditions such as temperature on the production of secondary metabolites.
北極や南極のような極限環境下の土壌真菌について、(i)抗菌活性をスクリーニングし、(ii)二次代謝物質の分泌とその温度変化への応答を検討した。マレーシア国立南極研究センターが有する真菌株のうち、南極海洋のキングジョージ島と高緯度北極スバールバル諸島のホーンサンドから採取された計40株を用い、プラグアッセイ法を用いてヒト感染性微生物数種に対する抗菌活性をスクリーニングした。菌株の約45%は少なくとも1種の微生物に対する抗菌活性を示し、特に良好な生物活性を示した3つの真菌分離株について、異なる温度(4、10、15、28℃)で分泌される二次代謝物質プロファイリングを行った。様々な温度での真菌の代謝産物を検討した結果、温度などの環境条件が二次代謝産物生成に影響を及ぼすことが確認された。

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