Occurrence of deoxynivalenol in an elderly cohort in the UK: a biomonitoring approach

The toxicity of graphene oxide affected by algal physiological characteristics: A comparative study in cyanobacterial, green algae, diatom

Though the main toxic mechanisms of graphene oxide (GO) to algae have been accepted as the shading effect, oxidative stress and mechanical damage, the effect of algal characteristics on these three mechanisms of GO toxicity have seldom been taken into consideration. In this study, we investigated GO toxicity to green algae (Chlorella vulgaris, Scenedesmus obliquus, Chlamydomonas reinhardtii), cyanobacteria (Microcystis aeruginosa) and diatoms (Cyclotella sp.). The aim was to assess how the physiological characteristics of algae affect the toxicity of GO. Results showed that 10 mg/L of GO significantly inhibited the growth of all tested algal types, while S. obliquus and C. reinhardtii were found to be the most susceptible and tolerant species, respectively. Then, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the physiological characteristics of the assessed algae. The presence of locomotive organelles, along with smaller and more spherical cells, was more likely to alleviate the shading effect. Variations in cell wall composition led to different extents of mechanical damage as shown by Cyclotella sp. silica frustules and S. obliquus autosporine division being prone to damage. Meanwhile, growth inhibition and cell division were significantly correlated with the oxidative stress and membrane permeability, suggesting the latter two indicators can effectively signal GO toxicity to algae. The findings of this study provide novel insights into the toxicity of graphene materials in aquatic environments.

Human Mycotoxin Biomonitoring: Conclusive Remarks on Direct or Indirect Assessment of Urinary Deoxynivalenol

Deoxynivalenol is one of the most ubiquitous mycotoxins in the Western diet through its presence in cereals and cereal products. A vast amount of studies indicate the worrying level of exposure to this toxin, while even high percentages of the population exceed the tolerable daily intake. To evaluate and assess dietary exposure, analysis of urinary levels of deoxynivalenol and its glucuronides has been proposed as a reliable methodology. An indirect preliminary method was used based on the cleavage of deoxynivalenol glucuronides through the use of enzymes (β-glucuronidase) and subsequent determination of "total deoxynivalenol" (sum of free and released mycotoxins by hydrolysis). Next, a direct procedure for quantification of deoxynivalenol-3-glucuronide and deoxynivalenol-15-glucuronide was developed. As deoxynivalenol glucuronides reference standards are not commercially available, the indirect method is widely applied. However, to not underestimate the total deoxynivalenol exposure in urine, the direct and indirect methodologies need to be compared. Urinary samples (n = 96) with a confirmed presence of deoxynivalenol and/or deoxynivalenol glucuronides were analysed using both approaches. The indirect method clarified that not all deoxynivalenol glucuronides were transformed to free deoxynivalenol during enzymatic treatment, causing an underestimation of total deoxynivalenol. This short communication concludes on the application of direct or indirect assessment of urinary deoxynivalenol.

Multimycotoxin Exposure Assessment in UK Children Using Urinary Biomarkers-A Pilot Survey

Cereal foods are commonly contaminated with multiple mycotoxins resulting in frequent human mycotoxin exposure. Children are at risk of high-level exposure because of their high cereal intake relative to body weight. Hence, this study aims to assess multimycotoxin exposure in UK children using urinary biomarkers. Spot urines (n = 21) were analyzed for multimycotoxins (deoxynivalenol, DON; nivalenol, NIV; ochratoxin A, OTA; zearalenone, ZEN; α-zearalenol, α-ZEL; β-zearalenol, β-ZEL; T-2 toxin, T-2; HT-2 toxin, HT-2; and aflatoxin B₁ and M_1, AFB₁, AFM₁) using liquid chromatography-coupled tandem mass spectrometry. Urine samples frequently contained DON (13.10 ± 12.69 ng/mL), NIV (0.36 ± 0.16 ng/mL), OTA (0.05 ± 0.02 ng/mL), and ZEN (0.09 ± 0.07 ng/mL). Some samples (1-3) contained T-2, HT-2, α-ZEL, and β-ZEL but not aflatoxins. Dietary mycotoxin estimation showed that children were frequently exposed to levels exceeding the tolerable daily intake (52 and 95% of cases for DON and OTA). This demonstrates that UK children are exposed to multiple mycotoxins through their habitual diet.

Fusarium head blight and mycotoxins in wheat: prevention and control strategies across the food chain

With 744 million metric tons produced in 2017/2018, bread wheat (Triticum aestivum) and durum wheat (Triticum durum) are the second most widely produced cereal on a global basis. Prevention or control of wheat diseases may have an enormous impact on global food security and safety. Fusarium head blight is an economically debilitating disease of wheat that reduces the quantity and quality of grain harvested, and may lead to contamination with the mycotoxin deoxynivalenol, which affects the health of humans and domesticated animals. Current climate change scenarios predict an increase in the number of epidemics caused by this disease. Multiple strategies are available for managing the disease including cultural practices, planting less-susceptible cultivars, crop rotation, and chemical and biological controls. None of these strategies, however, is completely effective by itself, and an integrated approach incorporating multiple controls simultaneously is the only effective strategy to limit the disease and reduce deoxynivalenol contamination in human food and animal feed chains. This review identifies the available tools and strategies for mitigating the damage that can result from Fusarium head blight.