Bajpai Vivek K, Kim Hak Ryul, Hou Ching Tsang, Kang Sun Chul
Department of Biotechnology, Daegu University, Kyoungsan, Kyoungbook, Republic of Korea.
J Ind Microbiol Biotechnol. 2009 May;36(5):695-704. doi: 10.1007/s10295-009-0539-6. Epub 2009 Mar 4.
Microbial modification of polyunsaturated fatty acids can often lead to special changes in their structure and in biological potential. Therefore, the aim of this study was to develop potential antifungal agents through the microbial conversion of docosahexaenoic acid (DHA). Bioconverted oil extract of docosahexaenoic acid (bDHA), obtained from the microbial conversion of docosahexaenoic acid (DHA) by Pseudomonas aeruginosa PR3, was assessed for its in vitro and in vivo antifungal potential. Mycelial growth inhibition of test plant pathogens, such as Botrytis cinerea, Colletotrichum capsici, Fusarium oxysporum, Fusarium solani, Phytophthora capsici, Rhizoctonia solani and Sclerotinia sclerotiorum, was measured in vitro. bDHA (5 microl disc(-1)) inhibited 55.30-65.90% fungal mycelium radial growth of all the tested plant pathogens. Minimum inhibitory concentrations (MICs) of bDHA against the tested plant pathogens were found in the range of 125-500 microg ml(-1). Also, bDHA had a strong detrimental effect on spore germination for all the tested plant pathogens. Further, three plant pathogenic fungi, namely C. capsici, F. oxysporum and P. capsici, were subjected to an in vivo antifungal screening. bDHA at higher concentrations revealed a promising antifungal effect in vivo as compared to the positive control oligochitosan. Furthermore, elaborative study of GC-MS analysis was conducted on bioconverted oil extract of DHA to identify the transformation products present in bDHA. The results of this study indicate that the oil extract of bDHA has potential value of industrial significance to control plant pathogenic fungi.
多不饱和脂肪酸的微生物修饰常常会导致其结构和生物活性发生特殊变化。因此，本研究的目的是通过二十二碳六烯酸（DHA）的微生物转化来开发潜在的抗真菌剂。对铜绿假单胞菌PR3对二十二碳六烯酸（DHA）进行微生物转化得到的二十二碳六烯酸生物转化油提取物（bDHA）的体外和体内抗真菌潜力进行了评估。在体外测定了对灰葡萄孢、辣椒炭疽病菌、尖孢镰刀菌、茄类镰刀菌、辣椒疫霉、立枯丝核菌和核盘菌等试验植物病原菌的菌丝生长抑制作用。bDHA（5微升/圆片）抑制了所有受试植物病原菌55.30 - 65.90%的真菌菌丝径向生长。发现bDHA对受试植物病原菌的最低抑菌浓度（MIC）在125 - 500微克/毫升范围内。此外，bDHA对所有受试植物病原菌的孢子萌发都有很强的抑制作用。进一步对三种植物病原真菌，即辣椒炭疽病菌、尖孢镰刀菌和辣椒疫霉进行了体内抗真菌筛选。与阳性对照低聚壳聚糖相比，较高浓度的bDHA在体内显示出有前景的抗真菌效果。此外，对DHA生物转化油提取物进行了GC-MS分析的详细研究，以鉴定bDHA中存在的转化产物。本研究结果表明，bDHA油提取物在控制植物病原真菌方面具有潜在的工业应用价值。
