Novel detoxification of the trichothecene mycotoxin deoxynivalenol by a soil bacterium isolated by enrichment culture.
A mixed microbial culture capable of metabolizing deoxynivalenol was obtained from soil samples by an enrichment culture procedure. A bacterium (strain E3-39) isolated from the enrichment culture completely removed exogenously supplied deoxynivalenol from culture medium after incubation for 1 day. On the basis of morphological, physiological, and phylogenetic studies, strain E3-39 was classified as a bacterium belonging to the Agrobacterium-Rhizobium group. Thin-layer chromatographic analysis indicated the presence of one major and two minor metabolites of deoxynivalenol in ethyl acetate extracts of the E3-39 culture filtrates. The main metabolite was identified as 3-keto-4-deoxynivalenol by mass spectroscopy and 1H and 13C nuclear magnetic resonance analysis. The immunosuppressive toxicity of 3-keto-4-deoxynivalenol was evaluated by means of a bioassay based on the mitogen-induced and mitogen-free proliferations of mouse spleen lymphocytes. This compound exhibited a remarkably decreased (to less than one tenth) immunosuppressive toxicity relative to deoxynivalenol, indicating that the 3-OH group in deoxynivalenol is likely to be involved in exerting its immunosuppressive toxicity. Strain E3-39 was also capable of transforming 3-acetyldeoxynivalenol but not nivalenol and fusarenon-X.
Shima
J
J
National Food Research Institute, Ibaraki, Japan.
Takase
S
S
Takahashi
Y
Y
Iwai
Y
Y
Fujimoto
H
H
Yamazaki
M
M
Ochi
K
K
D000818:Animals; D001419:Bacteria / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D001431:Bacteriological Techniques; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D007166:Immunosuppressive Agents / Q000493:pharmacokinetics / Q000633:toxicity; D066298:In Vitro Techniques; D008658:Inactivation, Metabolic; D008213:Lymphocyte Activation / Q000187:drug effects; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008854:Microscopy, Electron; D015394:Molecular Structure; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012230:Rhizobiaceae / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism; D012988:Soil Microbiology; D014255:Trichothecenes / Q000737:chemistry / Q000493:pharmacokinetics* / Q000633:toxicity
D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D007166:Immunosuppressive Agents; D012336:RNA, Ribosomal, 16S; D014255:Trichothecenes; C007262:deoxynivalenol