Wheat trichothecene mycotoxins

Kalinoski et al. [32] has applied this method to the determination of tri-chothecene mycotoxins in wheat. The methods were based on chemical ionisation MS and collision-induced dissociation tandem MS and enabled the rapid identification of ppm levels of several trichothecene mycotoxins. Supercritical carbon dioxide is shown to allow identification of mycotoxins with minimum sample handling in complex natural matrices such as wheat. Tandem MS techniques are employed for unambiguous identification of compounds of varying polarity, and false positives from isobaric compounds are avoided. Capillary column SCFC-MS of a SCF extract of the same sample was also performed, and detection limits in the ppb range appear feasible. 

Contaminated grains (corn, wheat, and milo) are the sources of mycotoxin exposure for horses. The most commonly involved mycotoxins are aflatoxins, T-2, and fumonisin Bj. Aflatoxins will cause nonspecific effects, such as a poor thriving condition, hemorrhages, and abortions. T-2 is a trichothecene mycotoxin that causes prolonged bleeding times and digestive tract inflammation in affected horses. 

A GC/MS technique has been developed for the detection of trichothecene mycotoxins. The technique has been used to quantitate the trichothecene deoxynivalenol in corn, wheat and mixed feeds. The trichothecenes are derivatized with heptafluorobutyrylimidazole and the derivatives are separated by gas chromatography. 

Casale, W. L. Inhibition of protein synthesis in maize and wheat by trichothecene mycotoxins and hybridoma-based enzyme immunoassay for deoxynivalenol. 168 pp. Avail. Univ. Microfilms Int., Order No. DA8722822. From Diss. Abstr. Int B 1988,48(8), 2167. 1987. 

Suzuki T, Kurisa M, Hoshino Y, Ichinoe M, Nose N, Tokumaru Y, Watanabe A (1980) Production of Trichothecene Mycotoxins of Fusarium sp. in Wheat and Barley Harvested in Saitama Prefecture. J Food Hyg Soc Jpn 21 43... 

Young, J. C. and Games, D. E. 1994. Analysis of Fusarium mycotoxins by gas chromatography—Fourier transform infrared spectroscopy. J. Chromatogr. A 663 211—218. Suzuki, T, Kurisu, M., Hoshimo, Y., Ichinoe, M., Nose, N., Tokumaru,Y., andWatanabe, A. 1981. Production of trichothecene mycotoxins of Fusarium species in wheat and barley harvested in Saitama prefecture. J. FoodHyg. Soc. 22 197-205. 

The trichothecene mycotoxins deoxynivalenol (vomitoxin), nivalenol and fusar-enon-X (Figure 7.2) have been measured in wheat extracts using HPLC with postcolumn photolysis (Hg vapour lamp, 2.3-3 min residence time) and ED (parallel GCEs, -I-1.10 V and -1-0.85 V vs Ag/AgCl). An ODS-modified silica analytical colunm was used with methanol-aq. sodium chloride (50 nrniol L ) (15 -I- 85) as eluent. LoDs were 1-2 ng on-column. 

Two trichothecene mycotoxins (nivalenol and deoxynivalenol) and two related esters (3-acetyl- and 15-0-acetyl-4-deoxynivalenol) were extracted from wheat flour and separated on a Cjg coluitm (2 = 220nm). A complex 36-min 92/8 - 0/100 (9/10 water/acetonitrile)/acetonitrile gradient gave good resolution and peak shape [1100]. Standards containing 3 ppm of each compound were easily detected. 

Sulyok et al. [113] reported the first validated method for the determination of 39 mycotoxins in wheat and maize by liquid chromatography with electrospray ionization-triple quadmpole mass spectrometry (LC/ESI-MS/MS) without the need for any cleanup. The 39 analytes included A and B trichothecenes (including deoxynivalenol-3-glucoside), ZEN and related derivatives, fumonisins, enniatins, ergot alkaloids, ochratoxins, aflatoxins, and moniliformin, and six trichothecene mycotoxins (NIV, DON, fusarenon-X, 15-acetyldeoxynivalenol, 3-acetyldeoxynivalenol, and T-2 toxin). 

Some microorganisms are also able to transform trichothecenes into less toxic compounds. For example, rumenal bacteria, bacteria from the large intestine of chickens, and bacterial populations from soil samples, were capable of transforming deoxynivalenol into 3-acetyldeoxynivalenol or 3-keto-4-deoxynivalenol (Binder et ah, 2000 Swanson et ah, 1987 He et ah, 1993 Shima et ah, 1997). Therefore, it seems likely that the development of wheat crops with the capability of eliminating this mycotoxin or bio-treatments could possibly be developed as a feasible strategy. 

Knoll, A., Niessen, L., and Vogel, R. F. (2000). Application of a PCR protocol for the diagnosis of trichothecene producing Fusarium species in deoxynivalenol contaminated wheat. Mycotoxin Res. 16A, 240-243. 

Contamination occurs primarily in wheat, barley, rye, and maize. Type A trichothecenes include mainly T-2 toxin, HT-2, and diacetoxyscirpenol (DAS) mycotoxins of the group B include mainly 4-deoxynivalenol (DON), commonly known as vomitoxin, and nivalenol (NIV). Toxic effects include nausea, vomiting, visual disorder, vertigo, throat irritation, and feed refusal in farm animals. The most toxic is T-2, followed by DAS and NIV, with DON being the least toxic in acute toxicity studies but the most widespread in grains worldwide and therefore the most studied. Issues related to chemical and physical data, occurrence, toxicity, absorption, distribution, and metabolism of trichothecenes are reviewed in WHO (89) and IARC (34). Physicochemical data for some selected Fusarium toxins is given by Sydenham et al. (90). The molecular structures of the main trichothecenes are shown in Fig. 9. 

One of the metabolites of the trichothecene family of mycotoxins, termed "neosolanoil" (246) was isolated from Florunner peanuts and identified as 3a-hydroxy-4B, 8a-15-triacetoxy-12,13-epoxy trichothec-9-ene. This toxin was shown to be a potent plant growth inhibitor active to 10 % in the wheat coleoptile bioassay. 

Several species of Fusarium infect com, wheat, barley, and rice. Under favorable conditions they elaborate a number of different types of tetracyclic sesquiterpenoid mycotoxins that are composed of the epoxytrichothecene skeleton and an olefinic bond with different side chain substitutions (fig. 9). Based on the presence of a macrocyclic ester or ester-ether bridge between C-4 and C-15, trichothecenes are generally classified as macrocyclic (type C) or nonmacrocyclic (types A and B) (table 5). Other fungal genera producing trichothecenes are Myrothecium, Trichoderma, Trichothecium, Acremonium, Verticimonosporium and Stachybotrys. The term trichothecenes is derived from trichothecin, the first compound isolated in this group [115, 147-153]. 

Zearalenon is a natural contaminator of maze, wheat, oats, barley and hay. The synthesis of the toxin is enhanced by high humidity and low temperatures and is also often found together with trichothecenes. This mycotoxin is synthesized by several strains of Fusarium mainly by Fusarium sporotrichoides and Fusarium graminearum etc. 

Trichothecenes constitute a mycotoxin family produced by fungal spiecies from several genera, notably Fusarium, Stachybotrys, Myrothecium, Trichothecium, Trichoderma, Cylindrocarpon, Verticimonosporium, Acremonium, and Phomopsis. Most of the trichothecenes that have been isolated and characterized chemically are from Fusarium species that grow in the field and are distributed worldwide, representing the important pathogens of grains and other food and feed plants. Trichothecenes ap>p)ear as natural contaminants in cereal grains such as wheat, barley, oat, maize, rice, and derived products, such as bread, malt and beer (Scott, 1989). 

Several surveys suggest that the most prevalent trichothecenes are deoxynivalenol (DON), nivalenol, 3-acetyl-DON (3-AcDON) and 15-acetyl-DON (15-AcDON), as type-B trichothecenes, and HT-2 toxin and T-2 toxin, as type-A trichothecenes. They are mainly found on maize, oats, barley, and wheat. The latter, espedally durum wheat, which is used nearly exclusively for the production of pasta, is susceptible to Fusaria infection and is often highly contaminated with DON. In European agricultural commodities type-A trichothecenes usually occur less frequently and at lower concentrations than DON. The simultaneous occurrence of DON with other Fusarium mycotoxins mainly type-B trichothecenes and zearalenone, has been reported for a variety of agricultural commodities (Gareis et al., 1989 Petterson, 1992, as cited in Krska et al., 2001). 

In the years 2007, 2008, and 2009, altogether 175 samples of cereals produced in Slovenia were collected at farms, among them 79 samples of maize, 39 samples of barley, and 34 samples of wheat. In the samples, among analysed mycotoxins, trichothecenes were determined using the analytical procedure mentioned above. 

Activity of similar magnitude was demonstrated by several known antibiotics/ including novobiocin/ neomycin/ gentamicin/ and cephalexin (23). Mycotoxins evaluated in the wheat col optile assay were extremely active as growth in bitors/ retaining activity at concentrations as low as 10 M for verucarin A and J and for trichoverrin B (24). Several of the trichothecenes and cytochalasins evaluated were active at 10" M with cytochalasin H and deacetylcytochalasin H still active at 10" M concentrations. One very active compound in this assay is abscisic acid (ABA) which/ as yet/ has no agrochemical application in its native state. ABA inhibits 100/ 90/ and 69% at 10 / 10" and 10 M respectively (18). ... 

Aflatoxins (AFTs) and trichothecene toxins are secondary metabolites of the fungi Aspergillus spp. and Fusarium spp., respectively. Both of these mycotoxins pose a substantial agricultural problem since they often are produced by the fungi in wheat and maize (Goldblatt, 1969 Dashek et al., 1986). Also, they have been reported to produce toxins in soybean and rice cultures (Richardson et al., 1985). 

---