Microbial acetyl conjugation of T-2 toxin and its derivatives

Abstract

The acetyl conjugation of T-2 toxin and its derivatives, the 12,13-epoxytrichothecene mycotoxins, was studied by using mycelia of trichothecene-producing strains of Fusarium graminearum, F. nivale, Calonectria nivalis, and F. sporotrichoides. T-2 toxin was efficiently converted into acetyl T-2 toxin by all strains except a T-2 toxin-producing strain of F. sporotrichoides, which hydrolyzed the substrate to HT-2 toxin and neosolaniol. HT-2 toxin was conjugated to 3-acetyl HT-2 toxin as an only product by mycelia of F. graminearum and C. nivalis, but was also resistant to conjugation by both F. nivale and F. sporotrichioides. Neosolaniol was also biotransformed selectively into 3-acetyl neosolaniol by F. graminearum. However, 3-acetyl HT-2 toxin was not acetylated by any of the strains under the conditions employed, but was hydrolyzed to HT-2 toxin by F. graminearum and F. nivale. This is the first report on the biological 3a-0-acetyl conjugation of T-2 toxin and its derivatives. T-2 toxin, 4,8,15-diacetoxy-8a-(3-methylbutyloxy)-3a-hydroxy-12,13-epoxytrichothec-9ene, is one of the most important trichothecene mycotoxins occurring naturally in agricultural products and associated with serious field toxicoses of humans and animals (5, 6). The metabolic fates of this toxin have been studied in fungi (12-14), livers (3, 9, 10), rats and mice (11), and chickens (T. Yoshizawa, S. P. Swanson, and C. J. Mirocha, submitted for publication). Up to

Thirty-five Years of Research on Deoxynivalenol, a Trichothecene Mycotoxin: with Special Reference to Its Discovery and Co-occurrence with Nivalenol in Japan

“…HT-2 toxin was conjugated to 3-acetyl HT-2 toxin as an only product by mycelia of F. graminearum and C. nivalis, but was resistant to conjugation by both F. nivale and F. sporotrichioides. Only F. graminearum transformed neosolaniol into 3-acetylneosolaniol.This is the first report on the biological 3α-O-acetyl conjugation of T-2 toxin and its derivatives 97) . The acetyl conjugation of T-2 toxin was also observed in vegetative mycelia of some trichothecene non-producing fungal species (our unpublished results).…”

“…The acetyl conjugation of T-2 toxin, HT-2 toxin and neosolaniol, each having a C-3α hydroxy group, was also studied by using mycelia of trichothecene-producing strains of F. graminearum, F. nivale (=F. kyushuense), Calonectria nivalis, and F. sporotrichioides 97) . T-2 toxin was efficiently converted into acetyl T-2 toxin by all strains except a T-2 toxin-producing strain of F. sporotrichioides.…”

Partial purification and characterization of an esterase from fusarium sporotrichioides

“…These toxicological effects are correlated with their chemical characteristics. Type A TCTCs possess hydroxyls or esterified hydroxyls at the C-3,4,7,8, or 15 positions; hydrolysis of the ester side chain generally results in a decrease of toxicity in experimental animals [Claridge andSchmitz, 1978,1979;Ueno, 1983;Yoshizawa and Morooka, 1975;Yoshizawa et al, 1980aYoshizawa et al, , 1980bYoshizawa et al, . 1982Swanson and Corley, 19891. Whereas metabolic hydrolysis of the ester bond of TCTCs by mammalian enzymes plays an important role in determining the toxicity of the toxin, the multiplicity of TCTCs produced by various fusaria was also attributed to the hydroxylase and esterase enzymes [Anonymous, 1983;Baldwin et al, 1986;Beeton and Bull, 1989;Desjardins et al, C 1996WileyLiss, Inc 1993Miller and Trenholm, 1994;Swanson and Corley, 1989;Udell and Dewick, 1989;Ueno, 19831.…”

Metabolism of T-2 toxin in Curtobacterium sp. strain 114-2

“…The biotransformation of T-2 toxin into HT-2 toxin was already demonstrated in our laboratory, by use of the microsomal carboxyesterase of rat liver (11,12), and by Yoshizawa et al (27,28) in trichothecene-producing fungal cells. However, transformation of HT-2 toxin into T-2 triol was not demonstrated in these mammalian and fungal preparations.…”