Colonization of barley grain by Fusarium sporotrichioides and T-2 toxin formation in the presence of Aspergillus flavus, Penicillium verrucosum, and Hyphopichia burtonii were studied at 20 and 30 degrees C and at 0.97, 0.95 or 0.90 aw during 3 weeks' incubation. Colonization of grain was assessed from frequency of seed infection and numbers of colony forming units (cfu) produced and by observation of hyphal extension on the grain surface from germinating spores while concentrations of T-2 toxin were determined by enzyme-linked immunosorbent assay using monoclonal antibodies. Germination of F. sporotrichioides spores was unaffected by the presence of other species under all conditions. However, subsequent colonization of barley grain by F. sporotrichioides was either completely inhibited or markedly decreased by the the presence of other fungi irrespective of the aw, temperature or competing species involved. T-2 toxin production occurred only at 20 degrees C and 0.97 or 0.95 aw, and mostly within the first 7 days: production of T-2 toxin by F. sporotrichioides was significantly greater in the presence of A. flavus and P. verrucosum throughout the 3-week incubation period under most conditions. T-2 toxin production was only slightly decreased by the presence of H. burtonii, despite the apparent lack of growth of F. sporotrichioides.
Aflatoxin B1 (B1), T-2 toxin (T2), and ochratoxin A (OA) were assayed in a single extract from barley grain by using competitive enzyme linked immunosorbent assays (ELISAs) with monoclonal antibodies. B1 and T2 monoclonal antibodies were conjugated to horseradish peroxidase for direct competitive ELISA while an indirect competitive ELISA was used for OA determination. The competitive ELISA detected 0.1 ng/mL of B1f 10 ng/mL of T2, or 1 ng/mL of OA. Acetonitrile- 0.5% KCI-6% H2S04 (89 + 10 + 1 ) extracts of barley grain either were diluted 1:10 for direct assay or were subjected to a simple liquid-liquid cleanup procedure to concentrate the extract 10:1 before assay. For cleanup, water was added to the acetonltrile extract to partition water-soluble interfering substances, and then the mycotoxins were re-extracted with chloroform. The chloroform extract was evaporated to dryness and redissolved in Tris HCI buffer for ELISA. The mean recoveries from barley spiked with 4-60 ng/g of B1( 50-5000 ng/g of T2, and 5-500 ng/g of OA were, respectively, 93.8, 80.6, and 95.8%. The mean within-assay, Inter-assay, and subsample coefficients of variation by ELISA of barley grain colonized with toxigenic fungi were <12% for Bi and OA but as high as 17% forT2.
i p m s~ s c d p.nut gcllohlpr rrpntsd u m*t, .wep!ibla n hI& lulccptibk Lo lo +fm mlanivtian dmhydrstd, rm. Nrr, rtmal, und.rmgad trod by ilrp@U~s lLwr (IVSCAF! were tested for natural lssd inBmon by A tLwr and other h a in IW or mm rophted 6skl t d l at ICRISAT Canter. hhncbcru, In& in 1878.1881. U n h d p& wem urn. pbd bcbm msNPIty U opbmum m r i w ( n d huroct! and wbcn averrmam 0.1~ hwcltl uld d cumlned lor i&. Um by A 8.w' and othn In the lW md 1881 Riny d 16U%@d-y u u r m s , o n l y f o v r g a~( m e m i . t u r t d thm s u =~l I b k J w r m tntsd, md seed werr dm tested fa J1.r--lent In dl -D# ' &on by A, h w s m S e n d ' I & h w w nn M ~~n a W p ( . L M & m i n a n t i n~m l r u h r n d r m h u r t e n n i k t h e d i t y of A. h& to pmetmn tb; testa d, and wrr p u t d d y mmmm in marmahue 1 colonize the s o d whnsu in the field, seed in-seed o f d genotypr io d l rainy -, -.the 1BB) A . & v u r i s i n f l d b y h a o r s~s r r b d l r s r i rn i r~y r s r m . I n N i g e r h A f~-~
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.