T-2 Tetraol

The stabilities of tritium-labeled T-2, HT-2, and T-2 tetraol were studied in blood and urine at -70 degrees, 4 degrees, and 23 degrees C for 6 months in the presence of EDTA or NaF. Samples were counted with a radiochromatographic scanner and results indicated the stability of T-2 tetraol greater than T-2 greater than HT-2. Toxins were most stable when stored at -70 degrees C, in the presence of NaF, and in urine (pH 6). They were less stable in saline (control, pH 7) and least stable in blood (pH 8). These results suggest that urine and T-2 tetraol are the biological fluid and metabolite of choice for diagnostic purposes.

The interactions of T-2 and its metabolite T-2 tetraol (hereafter tetraol) with CHO (Chinese hamster ovary cells) and CHO ribosomes were studied. T-2 was about 300-fold more potent at inhibiting protein synthesis in CHO than was tetraol. Association of T-2 with CHO was highly specific and achieved a maximum at a concentration producing complete inhibition of protein synthesis. Association of tetraol with CHO was of low specificity, but the specific fraction did correlate with the dose-response curve for protein synthesis inhibition. Binding of both T-2 and tetraol to isolated CHO ribosomes was quantitatively similar and highly specific. With isolated ribosomes, each toxin competed effectively for the binding of the other. Using intact cells, tetraol competed for T-2 cell association, but not the converse. The kinetics at physiological temperature for total and specific T-2 cell association were much more rapid than those for tetraol. Furthermore, the rate of tetraol-cell association was indistinguishable from the rate for cellular uptake of tritiated water. At 0 degrees C, there was a substantial association of T-2 with cells, whereas none was observed with tetraol. The kinetics of dissociation of both toxins from CHO were similar. We conclude that T-2 rapidly crosses the cell membrane of cells and binds to the intracellular target, the ribosomes. In contrast, tetraol is taken up by the cell much more slowly, and many more toxin molecules are found in the cell than there are ribosomes. It would appear that the main physical property of the toxins that brings about these results is the relative hydrophobicities of the molecules.(ABSTRACT TRUNCATED AT 250 WORDS)

Within the European Union (EU), edible insects need to be approved as "Novel Food" according to Regulation (EU) 2015/2283 and must comply with the requirements of European food law with regard to microbiological and chemical food safety. Substrates used for feeding insects are susceptible to the growth of Fusarium spp. and consequently to contamination with trichothecene mycotoxins. Therefore, the current study aimed to investigate the influence of T-2 and HT-2 toxins on the larval life cycle of yellow mealworm (Tenebrio molitor (L.)) and to study the transfer of T-2, HT-2, T-2 triol and T-2 tetraol in the larvae. In a 4-week feeding study, T. molitor larvae were kept either on naturally (oat flakes moulded with Fusarium sporotrichioides) or artificially contaminated oat flakes, each at two levels (approximately 100 and 250 μg/kg total T-2 and HT-2). Weight gain and survival rates were monitored, and mycotoxins in the feeding substrates, larvae and residues were determined using LC-MS/MS. Larval development varied between the diets and was 44% higher for larvae fed artificially contaminated diets. However, the artificially contaminated diets had a 16% lower survival rate. No trichothecenes were detected in the surviving larvae after harvest, but T-2 and HT-2 were found both in the dead larvae and in the residues of naturally and artificially contaminated diets.