Toxins

Crotalid envenomation carries the highest snakebite mortality rate in Brazil, yet its impact on the fetus during pregnancy remains unclear. In this study, we examined the effects of a moderate, nonlethal dose of Crotalus durissus terrificus venom (vCdt) on pregnant rats on gestational days 5 (V5, embryogenesis phase) and 10 (V10, organogenesis phase). We also evaluated whether antivenom could neutralize these effects. Exposure at V5 tended to increase the average weight of male and female fetuses, as well as the weight of their kidneys and livers. Some fetuses exhibited incomplete cranial ossification and supernumerary rib fragments. All of these effects were fully reversed by antivenom. Exposure at V10 reduced overall fetal weight and tended to increase placental weight while reducing the weights of the kidneys, liver, and heart in male and female fetuses. Antivenom only partially reversed these effects. Thus, vCdt is embryotoxic during embryogenesis and organogenesis, though antivenom therapy is more effective in the early stages of gestation.

The analytical characteristics of Lyngbya wollei toxin 4 (LWTX4), a rare derivative of saxitoxin (STX), remain insufficiently documented due to its limited availability. In the present study, therefore, LWTX4 was synthesized using the previously reported synthetic route developed by Looper to elucidate its fundamental chromatographic behavior. Additionally, three other paralytic shellfish toxin analogues, STX, decarbamoyl saxitoxin (dcSTX), and 12-epi-LWTX4, were prepared from a common intermediate. Analysis of synthetic LWTX4 using the AOAC OMA 2011.02 HPLC–PCOX–FLD method yielded a retention time of 19.8 min, which overlapped with that of STX, and revealed that its FLD response was one-fourteenth that of STX. Meanwhile, under the AOAC 2021 HILIC–MS/MS conditions, LWTX4 eluted at 7.29 min, producing major product ions at m/z 205.1204, 182.0926, 164.0822, and 110.0720. These chromatographic and mass spectrometric characteristics provide useful reference data for assessing the possible presence of LWTX4 during PST profiling of biological samples. The synthetic STX and dcSTX exhibited chromatographic behavior consistent with that of their corresponding certified reference materials (CRMs) under the standard HPLC–PCOX conditions, supporting the potential use of synthesis as a complementary approach to the isolation of PSTs from dinoflagellates for the preparation of CRMs.

Tomato is among the most widely cultivated vegetable crops worldwide. However, its high susceptibility to Alternaria is particularly concerning due to the ability of fungi of this genus to produce mycotoxins that pose potential health risks. Contamination of processed tomato products has been repeatedly reported in the literature, but little is known about the factors influencing contamination in field-grown processing tomatoes. In this study, we assessed the composition of the epidermal microbiota of processing tomato fruits in relation to Alternaria and mycotoxin contamination levels. Tomato crops exhibiting varying levels of contamination (based on symptom assessment, qPCR and LC-MS/MS analysis) were selected, and both healthy and diseased fruits were sampled. Our results revealed that processing tomatoes can be heavily contaminated with Alternaria mycotoxins at harvest. Visual symptoms were not reliable predictors of toxicological risk: the observed association between Stemphylium abundance and disease severity raises the hypothesis that Stemphylium may contribute to symptoms commonly attributed to Alternaria black spot. Conversely, fruits displaying atypical symptom profiles often contained high levels of Alternaria mycotoxins. Analysis of the tomato skin microbiota using 16S and ITS metabarcoding showed that fruit health status was associated with distinct microbial communities and identified several microbial modules associated with reduced disease severity and/or lower Alternaria relative abundance. Taxa belonging to the genera Wickerhamomyces, Gibellulopsis, Ectophoma, Bacillus, Liquorilactobacillus, and Enterococcus were predominantly associated with reduced disease symptoms and/or Alternaria relative abundance. These microbial groups represent promising targets for future isolation and experimental evaluation as biocontrol agents.