盐度和pH对红树根际土壤来源的曲霉属真菌F3的生长及分泌活性物质的影响

Effects of Salinity and pH on the Growth and Active Products-secreting of Aspergillus sp. F3 from the Mangrove Rhizosphere

摘要:

本研究考察了一株从中国海南东寨港红树林保护区的红海榄根际土壤中分离得到的曲霉属真菌F3在不同盐度和pH的SDA培养基中的生长和分泌抗菌活性代谢产物的变化。结果显示：高盐环境(3%~9％) 及偏碱性条件(pH 8~10) 有利于该真菌的生长。在初步优化培养基及培养条件的基础上, 通过发酵和有机溶剂萃取的方法获得了该真菌发酵液的乙酸乙酯浸膏, 得率为448 mg/L。该浸膏对多种微生物的生长具有明显的抑制作用, 其中对细菌Staphylococcus aureus、S. epidermidis、Sarcina lutea、Bacillus subtilis和Escherichia coli的MIC分别为31.3 μg/mL、31.3 μg/mL、7.8 μg/mL、7.8 μg/mL和125.0 μg/mL; 对真菌Candida albicans的MIC为125.0 μg/mL。研究同时表明：该乙酸乙酯浸膏还具有明显的细胞毒活性, 其对人脐静脉内皮细胞ECV304、人结肠癌细胞Lovo以及肝癌细胞HepG2的IC50分别为3.45 μg/mL、4.88 μg/mL和14.31 μg/mL。

Abstract:

An Aspergillus sp. strain F3 was isolated and identified from the rhizosphere soil of mangrove plant, Rhizophora stylosa Griff in Dongzhai harbor mangrove forest conservation in China. In this study, the effects of media salinity and pH on the mycelial biomass and the ability of producing antibacterial metabolites from this isolate were carefully analyzed. Results showed that this isolate can grow well on the SDA medium with higher salinity (3%~9%) and higher pH (8~10). Under the modified culturing conditions, this isolate can secret the antibacterial and antitumor metabolites. The extracts of acetic ether were about 448 mg/L of the fermentation broth. The antibacterial activities of the acetic ether extract were analyzed with bacteria and fungus. Results showed this extract can suppress the growth of Staphylococcus aureus、S. epidermidis、Sarcina lutea、Bacillus subtilis and Escherichia coli with MIC of 31.3 μg/mL, 31.3 μg/mL, 7.8 μg/mL, 7.8 μg/mL and 125.0 μg/mL, respectively. It can also suppress the growth of Candida albicans with MIC of 125.0 μg/mL. Further studies uncovered the cytotoxicity of this extract against the tumor cells, such as ECV304, Lovo and HepG2 with IC50 of 3.45 μg/mL, 4.88 μg/mL and 14.31 μg/mL respectively.