| The genus Lysobacter is a new type of important biocontrol bacteria,because of their strong antagonistic activities to many plant pathogenic fungi,bacteria and nematodes.In recent years,many new species of Lysobacter had been discovered continuously,they showed great application prospects for their high efficiency and broad-spectrum antagonism.In this thesis,two strains(L.soli 3.162 and L.gummosus 03100)were optimized cultural conditions and fermented,and their secondary metabolites were isolated and purified by chromatography,and those structures were identified by spectral data.The activities of acetylcholinesterase and nematicide of part compounds were assayedTotally,14 compounds were isolated and identified from strain L.soli 3.162.Among them,compounds 9,13,14,17,22 and 26 belonged to cyclic dipeptides,which were the main structural type.The other compounds included flavonoids,fatty acids,nucleosides and amides.Another 14 compounds that contained cyclic dipeptides,ketones,amides,nucleosides,glycosides,pyridines,amino acids and benzene derivatives were isolated and identified from strain L.gummosus 03100.Compound 21 is a new compound with a special odour.The structures of compounds 50 and 52 are being identified.AChE inhibitory activity of part compounds was assayed.Cyclo(AG),cyclo(PA),Cyclo(HV),cyclo(P-Hyp)exhibited AChE inhibitory activity with inhibition rates of 60.32%,34.32%,40.98%,31.63%at 100?g/mL,and the IC50 values were 62.536?M,64.085?M,42.500?M and 54.370?M,respectively.Nematocidal activity and nematode eggs hatching inhibition activity of compound 21 from strain L.gummosus 03100 was assayed.The results showed that the mortality of Caenorhabditis elegans and Meloidogyne incognita were 90%after 24 hours at 400 ppm,and the mortality of M.incognita were 50%after 24 hours at 200 ppm,indicating that compound 21 showed potentially nematocidal activity.Compound 21 had not shown inhibitory activity to the hatching of C.elegans eggs at 100?g/mL. |
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