Please use this identifier to cite or link to this item: http://hdl.handle.net/11189/6114
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dc.contributor.authorvan der Westhuizen, L
dc.contributor.authorShephard, GS
dc.contributor.authorSnyman, SD
dc.contributor.author.Abel, S
dc.contributor.authorSwanevelder, S
dc.contributor.authorGelderblom, WCA
dc.date.accessioned2017-11-13T06:38:21Z
dc.date.available2017-11-13T06:38:21Z
dc.date.issued1998
dc.identifier.issn1873-6351
dc.identifier.urihttps://doi.org/10.1016/S0278-6915(98)00012-X
dc.identifier.urihttp://hdl.handle.net/11189/6114
dc.description.abstracthe fumonisins and toxins produced by Alternaria alternata f. sp. lycopersici (AAL toxins) are structurally related mycotoxins that disrupt sphingolipid biosynthesis by inhibiting the rate-limiting enzyme, ceramide synthase. Rat primary hepatocytes were exposed to fumonisin B1 (FB1), its N-acetyl analogue, FA1, its fully hydrolysed analogue, AP1 and the AAL toxins (TA and TB) at concentrations of 1 μm for 40 hr in culture. The extent to which these compounds disrupt sphingolipid biosynthesis in hepatocytes in vitro was investigated by analysing the sphingosine (So) and sphinganine (Sa) levels by HPLC. The inhibition of ceramide synthase was irreversible as the Sa:So ratio was maximally increased by FB1 after 24 hr of exposure and the subsequent removal of FB1 had no effect on the ratio as compared with the 40-hr incubation period in the presence of FB1. The Sa concentration was significantly (P<0.01) increased in all the cultures treated with the different structurally related compounds, while only AP1 increased the So concentration significantly (P<0.05) above the control. As AP1 was found to be less effective in disrupting sphingolipid biosynthesis it would appear that the tricarballylic (TCA) moiety is required for maximal inhibition of ceramide synthase. The presence of an amino group appears not to be a requisite for activity, since FA1 increased the Sa:So ratio to the same extent as FB1. The AAL toxins TA and TB increased the Sa concentration significantly (P<0.01) above that of FB1 and FA1, while the Sa:So ratios were altered to the same extent. The structural requirements for the induction of cytotoxicity differ from those required for ceramide synthase inhibition as TA and TB were significantly (P<0.05 to P<0.01) less toxic to primary hepatocytes than FB1 at all the concentrations tested.en_US
dc.language.isoenen_US
dc.publisherFood and Chemical Toxicologyen_US
dc.rights.urihttp://creativecommons.org/licenses/by-nc-sa/3.0/za/
dc.subjectAlternaria alternata f. sp. lycopersicien_US
dc.subjectN-acetyl analogueen_US
dc.subjectSphingosine (So)en_US
dc.subjectSphinganine (Sa)en_US
dc.titleInhibition of sphingolipid biosynthesis in rat primary hepatocyte cultures by fumonisin B1 and other structurally related compoundsen_US
dc.typeArticleen_US
Appears in Collections:Edu - Journal Articles (DHET subsidised)
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