Urban areas are expanding rapidly and experience diverse and complex contamination of their surface waters. Addressing these issues requires different tools to describe exposures and predict toxicological risk to exposed biota. We surveyed 21 stormwater management ponds in Brampton, Ontario using three types of sampling methods deployed concurrently: time-integrated water sampling, biofilms cultured on artificial substrates, and organic-diffusive gradients in thin films (o-DGT) passive samplers. Our objective was to compare pesticide occurrences and concentrations to inform monitoring in stormwater ponds, which reflect pesticide pollution in urban areas. We detected 82 pesticides across the three sampling matrices, with most detections occurring in o-DGT samplers. The in situ accumulation of pesticides in o-DGTs during deployment and the high analytical sensitivity achieved establishes o-DGTs as excellent tools for capturing the mixtures of pesticides present. Water and biofilm sampling demonstrated that pesticide concentrations available for uptake are relatively low, with most below toxicological thresholds. Yet our results demonstrate that urban areas are subject to a wide range of pesticides, including herbicides, insecticides, and fungicides, and underscores the urgency of research to quantify the risks of chronic exposure to this chemical mixture.
Ilyonectria root rot of ginseng can greatly decrease crop yields often by 20–30% at time of harvest. We previously determined that the Ilyonectria siderophore N,N′,N″-triacetylfusarinine C (TAFC) is critical for the ginseng pathogens' virulence. TAFC enables the fungus to acquire iron from its environment, and once inside the cell, iron is typically released via enzymatic hydrolysis of TAFC's three ester moieties. This iron acquisition system has been extensively studied in Aspergillus fumigatus. Based on this system, we hypothesized that AfEstB, a well-characterized TAFC esterase produced by A. fumigatus, could be used for siderophore-targeted biocontrol of Ilyonectria. Application of purified recombinant AfEstB to ginseng roots inoculated with virulent I. mors-panacis demonstrated a significant protective effect, which disappeared when AfEstB was no longer applied. These data support the targeting of Ilyonectria iron acquisition mechanisms though enzymatic degradation of TAFC as an effective means of controlling Ilyonectria root rot of ginseng.
Challenges exist worldwide for the storage of animal feed, though year-long feeding of livestock is especially difficult in northern climates, including Canada. Usage of silage allows for crops to be harvested at the optimal nutritional value and stored for extended periods in customized storage systems. This case study investigated various feed management practices typical of small beef cattle feedlot farms in Southwestern Ontario, Canada. Crop samples were collected monthly and analyzed for mycotoxins and fungal secondary metabolites by liquid chromatography mass spectrometry (LC-MS/MS). Stored barley contained modest concentrations of deoxynivalenol and related compounds, as well as near trace amounts of fumonisin. Stored hay contained low concentrations of deoxynivalenol and beauvericin from the field. Hot spots of the Penicillium metabolite citrinin were detected after 7–8 months of storage in barley (39.2 ng g−1). Citrinin was also detected after 7–8 months in hay (16.3–17.5 ng g−1) along with the appearance of trace amounts of other storage toxins, including penitrem A (8.84 ng g−1), griseofulvin (34.8 ng g−1) and sterigmatocystin (14.1–261 ng g−1). This case study was a unique opportunity to use 'citizen science' to observe the onset of postharvest fungi and associated mycotoxins in various storage conditions allowing for the farmer to make necessary modifications before major problems begin. An improved understanding of the storage conditions that foster fungal growth and mycotoxin production in this working farm led to better agronomic practices, ultimately improving feed quality, livestock health, and profitability.
This review summarises developments published in the period from mid-2021 to mid-2022 on the analysis of a variety of matrices for mycotoxins. Important developments in all aspects of mycotoxin analysis, from sampling and quality assurance/quality control of analytical results, to the various detection and quantitation technologies ranging from single mycotoxin biosensors to comprehensive instrumental methods are presented and discussed. This non-exhaustive summary and associated discussion covers such technology as chromatography with targeted or non-targeted high resolution mass spectrometry, detection other than mass spectrometry such as fluorescence or diode array detection, biosensors, as well as assays using alternatives to antibodies. This collaborative critical review intends to guide readers to relevant research by briefly presenting the most important developments in mycotoxin determination published in the past year. This review also relays limitations of the presented methodologies, in order to provide a fulsome assessment of the analytical developments.
Aflatoxins B1 (AFB1) and G1 (AFG1) are carcinogenic mycotoxins that contaminate crops such as maize and groundnuts worldwide. The broadly accepted method to assess chronic human aflatoxin exposure is by quantifying the amount of aflatoxin adducted to human serum albumin. This has been reported using ELISA, HPLC, or LC-MS/MS to measure the amount of AFB1-lysine released after proteolysis of serum albumin. LC-MS/MS is the most accurate method but requires both isotopically labelled and unlabelled AFB1-lysine standards, which are not commercially available. In this work, we report a simplified synthetic route to produce unlabelled, deuterated and 13C6 15N2 labelled aflatoxin B1-lysine and for the first-time aflatoxin G1-lysine. Additionally, we report on the stability of these compounds during storage. This simplified synthetic approach will make the production of these important standards more feasible for laboratories performing aflatoxin exposure studies.
