Chemical Structure Analysis On Metabolite And Nematicidal Mechanism Of Streptomyces Venezuelae Snea253

Streptomyces venezuelae Snea253 was early screened against Meloidogyne incognita by Nematology Laboratory of Shenyang Agricultural University. We analyzed the nematicidal substance structure after separating and purifying liposoluble active components of Snea253 metabolite, and detected the antimicrobial activity and the nematicidal mechanism of Snea253. Results showed as follows:1. Purification of nematicidal components from Snea253 metabolite:The active ingredient was separated and purified by thin-layer chromatography, column chromatography and HPLC technique, meanwhile screened and checked by using M. incognita J2 as tracking target. The fermentation broth of Snea253 was initially prepared by centrifugal, alcohol precipitation, concentration and extraction. Then the brown syrupy color and fat-soluble crude extract was achieved. Further more, the crude extract was separated into 3 fractions by silica gel column chromatography respectively. The fractions were Snea253-Ⅰ(300 mg), Snea253-Ⅱ(450 mg) and Snea253-Ⅲ(400 mg), but only Snea253-I was found having nematicidal activity. And then two main content components were found in Snea253-Ⅰfraction by thin layer chromatography analysis, and the migration rates were Rf=0.24 and Rf=0.49, so it was suitable method for separation and purification of Snea253 by thin layer chromatography(TLC). Further more, Snea253-Ⅰ-1 (150 mg) and Snea253-Ⅰ-2 (45 mg) were obtained by TLC, and Snea253-I-1 was found with nematicidal activity. By the determination of High Performance Liquid Chromatography(HPLC),we found that the purity of Snea253-I-1 was more than 95%, which can be used for the determination and analysis by HPLC, High Resolution Mass Spectrometer (HRMS) and Nuclear Magnetic Resonance Instrument(NMR).2. Nematicidal structure analysis of Snea253-Ⅰ-1:The pure production Snea253-Ⅰ-1 Then the chemical structure was speculated as Dibutyl phthalate.3. Antimicrobial experiment of Snea253-I-1:The antimicrobial activity of Trichothecium roseum、Botrytis cinerea、Fusarium solani and Bacillus megaterium and others about 10 species of fungi and bacteria were carried out. Finally, we found that Snea253 could only inhibit the growth of Trichothecium roseum and Bacillus megaterium.4. Nematicidal mechanism of Snea253 against M.incognita:When the second Juvenile J2 was treated with Snea253, its action capability was inhibited and the mortality rate was about 87.3% after 48 h. Meanwhile, the breathing of J2 was also inhibited, and the body content fluid leakage was increased. Finally, the activity of J2 was inhibited until death.