Secondary Metabolites Of Three Antarctic Soil Microorganism And Their Biological Activities

The Antarctic is separated by other continents and surrounded by the Southern Ocean.It is a rocky land completely covered by ice sheets.Uninterrupted low temperature,tough wind,strong ultraviolet radiation and other factors all year round contribute to its unique ecological environment.In order to better adapt to the unique and harsh conditions of the Antarct,microorganisms living there need a variety of biochemical and physiological adjustments,which are often accompanied with changes in gene regulation and metabolic pathways.The changes of microbial metabolic pathways provide more possibilities for a variety of bioactive metabolites,which offer a good material for the purpose of screening bioactive compounds.This study includes two parts.The first part focuses on the separation and identification of extracts from Pseudomonas sp.A6-5,Pseudogymnoascus sp.G-F2 and Flavobacterium sp.A5-1.The three strains were cultured by fermentation methond,after which the fermentation liquor was extracted with ethyl acetate,and then spin-evaporated to get crude extract.The column chromatography and preparativehigh performance liquid chromatography were conducted to separate and purification the crude extract.Twenty compounds were finally identified by NMR and ESI-MS.In the second part,the corresponding angiogenic activities of these compounds were studied.Molecular docking method was used to study the interaction between protein and small molecules.The biological activity of these compounds was then predicted by analyzing the docking results.The docking results showed that compounds1-3,6,8,11,13-15,17,and 18 were located in the receptor ERα binding pocket,while compounds 4,5,7,12,16,19,and 20 did not enter the receptor ERα binding pocket.The order of the binding energy of the interaction between the compounds and the receptor ERα followed this trend: compunds KN1<1<2<13<12<14<4<16<19<18<7<6<15<20<8<5<11<17<3.It was predicted that compounds 1,2,13,14,18,6,15,8,11,17,and 3 may have angiogenic activity,while compounds 4,5,7,12,16,19,and 20 may not,or are weaker than the above compounds.Human umbilical endothelial cells(HUVECs)were employed as cellular models to study angiogenesis.Cell proliferation test results showed that compounds 1,2,13,15,14,18,6,and 11 could promote the proliferation of HUVECs.Cell scratch test results show that compounds 1,2,and 13 can boost the migration of HUVECs cells.The angiogenesis test of transgenic zebrafish showed that compound 1 could promote angiogenesis.The results of bioassay were in consistent with the theoretical prediction,indicating that the theoretical prediction could provide a reliable reference for carrying out biological activity experiments.In addition,compound 1 was also found to have antiepileptic activity in zebrafish model.But its mechanism needs further study.Together,this article separates,purifies,and identifies microorganisms and their active metabolites from Antarctic soil.By molecular docking and biochemistry-cellular biological methods,the resulting compounds with pro-angiogenesis activities were identified.Hopefully,this work will help to the development of pro-angiogenic drugs.