Browsing by Author "Medina, Angel"
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Item Open Access Acclimatisation of Fusarium langsethiae, F. poae and F. sporotrichioides to elevated CO2: impact on fungal growth and mycotoxin production on oat-based media(Elsevier, 2023-03-28) Kahla, Amal; Verheecke-Vaessen, Carol; Delpino-Deelias, Mariluz; Gutierrez-Pozo, Maria; Medina, Angel; Magan, Naresh; Doohan, FionaOats are highly susceptible to infection by Fusarium species, especially F. langsethiae, F. poae and F. sporotrichioides which contaminate the grain with mycotoxins. Climate change is expected to affect fungal colonisation and associated mycotoxin production. The objective of this study was to examine the effect of acclimatisation to elevated CO2 on the growth and mycotoxin production capacity of these fungal species. Strains of F. langsethiae (FL; seven strains), F. poae (FP; two strains) and F. sporotrichioides (FS; one strain) were acclimatised by sub-culturing for 10 generations at either 400 or 1000 ppm CO2 under diurnal temperature conditions. At each sub-culturing, the effect of acclimatisation to elevated CO2 on (a) lag phase prior to growth, (b) growth rate on oat-based media was assessed. Additionally, the production of type A trichothecenes and related toxic secondary metabolites of sub-cultures after 1, 7 and 10 generations were assessed using LC-MS/MS qTRAP. The results showed that Fusarium strains had an increased lag time and growth rate in response to the combined effect of sub-culturing and elevated CO2 levels. T-2 + HT-2 production was affected by elevated CO2 in strain FL4 (7.1-fold increase) and a decrease in strain FL1 (2.0-fold decrease) at the first sub-culturing and FS (1.3-fold decrease) after 7 sub-cultures compared to ambient conditions. The effect of sub-culturing on T-2 + HT-2 production varied depending on the fungal strain. For strain FL4, significantly less T-2 + HT-2 toxins were produced after 10 generations (4.4-fold decrease) as compared to that under elevated CO2 conditions after one sub-culture, and no change was observed under ambient conditions. The FS strain showed significant stimulation of T-2 + HT-2 toxin production after 10 sub-cultured generations (1.1-fold increase) compared to the initial sub-culture of this strain under elevated CO2 conditions. The production of other toxic secondary metabolites was generally not impacted by elevated CO2 conditions or by sub-culture for 10 generations, with the exceptions of FL1 and FP1. FL1 produced significantly more neosolaniol after 10 generations, when compared to those after 1 and 7, regardless of the CO2 conditions. For FP1, elevated CO2 significantly triggered beauvericin production after an initial sub-culture when compared to ambient conditions at the same sub-culture stage (29-fold). FP1 acclimatisation to elevated CO2 led to a decrease of beauvericin production after 10 generations when compared to 1 (6-fold). In contrast, sub-culturing for 10 generations compared to 1 under ambient CO2 conditions resulted in an increase in this toxin (12-fold).Item Embargo Aspergillus ullungdoensis sp. nov., Penicillium jeongsukae sp. nov., and other fungi from Korea(Elsevier, 2024-06-06) Lee, Hyang Burm; Nguyen, Thuong T.T.; Noh, So Jeong; Kim, Dong Hee; Kang, Ki Hyun; Kim, Su Jin; Kirk, Paul M.; Avery, Simon V.; Medina, Angel; Hallsworth, John E.Eurotiales fungi are thought to be distributed worldwide but there is a paucity of information about their occurrence on diverse substrates or hosts and at specific localities. Some of the Eurotiales, including Aspergillus and Penicillium species, produce an array of secondary metabolites of use for agricultural, medicinal, and pharmaceutical applications. Here, we carried out a survey of the Eurotiales in Korea, focusing on soil, freshwater, and plants (dried persimmon fruits and seeds of Perilla frutescens, known commonly as shiso). We obtained 11 species that—based on morphology, physiology, and multi-locus (ITS, BenA, CaM, and RPB2) phylogenetic analyses—include two new species, Aspergillus ullungdoensis sp. nov. and Penicillium jeongsukae sp. nov., and nine species that were known, but previously not described in Korea, Aspergillus aculeatinus, Aspergillus aurantiacoflavus, Aspergillus croceiaffinis, Aspergillus pseudoviridinutans, Aspergillus uvarum, Penicillium ferraniaense, Penicillium glaucoroseum, Penicillium sajarovii, and one, Penicillium charlesii, that was isolated from previously unknown host, woodlouse (Porcellio scaber). We believe that biodiversity surveys and identifying new species can contribute to set a baseline for future changes in the context of humanitarian crises such as climate change.Item Open Access Assessment of agricultural practices by Ethiopian women farmers: existence of gender disparities in access to mycotoxins training(Wageningen Academic, 2023-01-01) Cervini, Carla; Abegaz, B.; Mohammed, A.; Elias, R.; Medina, Angel; Gebre, K.; Verheecke-Vaessen, CarolEthiopia is one of the countries with the lowest gender-equality performance in sub-Saharan Africa being ranked 121/134 in terms of the magnitude and scope of gender disparities by the United Nations Women’s Organisation. Within the farming communities, women represent 70% of the labour force, but they are neglected from accessing training events run by Ethiopian Universities (e.g. Haramaya University). A survey to assess the existence of gender disparities among Ethiopian women farmers with respect to agricultural labour and mycotoxins knowledge was conducted on three hundred and forty-nine women from the Oromia and Amhara regions. A higher illiteracy rate was found in women compared to men from both Oromia and Amhara regions. Women played a key role in agricultural activities while having limited access to modern technologies compared to their male counterparts. Women were mainly responsible for sorting spoiled crops. Especially in Amhara, these were intended for home consumption, representing a serious health risk for local people. Overall, women from Amhara were more aware than women from Oromia about what mycotoxins are (e.g. aflatoxins), their impact and risk of occurrence in crops. Women in Amhara were also more intended to act towards mycotoxins in the future compared to women from Oromia. Only 0.24% of women have previously attended a training on mycotoxins. The radio seemed to be the most efficient way to deliver training to Ethiopian women farmers from these regions. Mycotoxins trainings were the second option of choice by all women surveyed. Such findings clearly stated the existence of gender inequality in the two Ethiopian regions considered. Empower women’s knowledge about mycotoxins will not only benefit agricultural income and the national economy, but it will also provide women the recognition they equally deserve alongside their male counterparts in future agricultural training programs and interventions.Item Embargo Biocontrol activities of yeasts or lactic acid bacteria isolated from Robusta coffee against Aspergillus carbonarius growth and ochratoxin A production in vitro(Elsevier, 2024-03-01) López Rodrígue, Claudia; Strub, Caroline; Fontana, Angélique; Verheecke-Vaessen, Carol; Durand, Noël; Beugré, Corinne; Guehi, Tagro; Medina, Angel; Schorr-Galindo, SabineBiocontrol Agents (BCAs) can be an eco-friendly alternative to fungicides to reduce the contamination with mycotoxigenic fungi on coffee. In the present study, different strains of bacteria and yeasts were isolated from Ivorian Robusta coffee. Their ability to reduce fungal growth and Ochratoxin A (OTA) production during their confrontation against Aspergillus carbonarius was screened on solid media. Some strains were able to reduce growth and OTA production by 85 % and 90 % and were molecularly identified as two yeasts, Rhodosporidiobolus ruineniae and Meyerozyma caribbica. Subsequent tests on liquid media with A. carbonarius or solely with OTA revealed adhesion of R. ruineniae to the mycelium of A. carbonarius through Scanning Electron Microscopy, and an OTA adsorption efficiency of 50 %. For M. caribbica potential degradation of OTA after 24 h incubation was observed. Both yeasts could be potential BCAs good candidates for Ivorian Robusta coffee protection against A. carbonarius and OTA contamination.Item Open Access Biovalorisation of crude glycerol and xylose into xylitol by oleaginous yeast Yarrowia lipolytica(BMC (part of Springer Nature), 2020-06-03) Prabhu, Vinayak Ashok; Thomas, Dominic J.; Ledesma-Amaro, Rodrigo; Leeke, Gary A.; Medina, Angel; Verheecke-Vaessen, Carol; Coulon, Frederic; Agrawal, Deepti; Kumar, VinodBackground Xylitol is a commercially important chemical with multiple applications in the food and pharmaceutical industries. According to the US Department of Energy, xylitol is one of the top twelve platform chemicals that can be produced from biomass. The chemical method for xylitol synthesis is however, expensive and energy intensive. In contrast, the biological route using microbial cell factories offers a potential cost-effective alternative process. The bioprocess occurs under ambient conditions and makes use of biocatalysts and biomass which can be sourced from renewable carbon originating from a variety of cheap waste feedstocks. Result In this study, biotransformation of xylose to xylitol was investigated using Yarrowia lipolytica, an oleaginous yeast which was firstly grown on a glycerol/glucose for screening of co-substrate, followed by media optimisation in shake flask, scale up in bioreactor and downstream processing of xylitol. A two-step medium optimization was employed using central composite design and artificial neural network coupled with genetic algorithm. The yeast amassed a concentration of 53.2 g/L xylitol using pure glycerol (PG) and xylose with a bioconversion yield of 0.97 g/g. Similar results were obtained when PG was substituted with crude glycerol (CG) from the biodiesel industry (titer: 50.5 g/L; yield: 0.92 g/g). Even when xylose from sugarcane bagasse hydrolysate was used as opposed to pure xylose, a xylitol yield of 0.54 g/g was achieved. Xylitol was successfully crystallized from PG/xylose and CG/xylose fermentation broths with a recovery of 39.5 and 35.3%, respectively. Conclusion To the best of the author’s knowledge, this study demonstrates for the first time the potential of using Y. lipolytica as a microbial cell factory for xylitol synthesis from inexpensive feedstocks. The results obtained are competitive with other xylitol producing organisms.Item Open Access Carbon dioxide production as an indicator of Aspergillus flavus colonisation and aflatoxins/cyclopiazonic acid contamination in shelled peanuts stored under different interacting abiotic factors(Elsevier, 2019-10-24) Garcia-Cela, Esther; Gari Sanchez, F. J.; Sulyok, Michael; Verheecke-Vaessen, Carol; Medina, Angel; Kruska, Rudolf; Magan, NareshAspergillus flavus is the main xerophylic species colonising stored peanuts resulting in contamination with aflatoxins (AFs) and cyclopiazonic acid (CPA). This study evaluated the relationship between storage of shelled peanuts under interacting abiotic conditions on (a) temporal respiration (R) and cumulative CO2 production, (b) dry matter losses (DMLs) and (c) aflatoxin B1 (AFB1) and CPA accumulation. Both naturally contaminated peanuts and those inoculated with A. flavus were stored for 7-days under different water activities (aw; 0.77–0.95) and temperatures (20–35°C). There was an increase in the temporal CO2 production rates in wetter and warmer conditions, with the highest respiration at 0.95 aw + A. flavus inoculum at 30°C (2474 mg CO2kg−1h−1). The DMLs were modelled to produce contour maps of the environmental conditions resulting in maximum/minimum losses. Maximum mycotoxin contamination was always at 0.95 aw although optimal temperatures were 25-30°C for AFs and 30-35°C for CPA. These results showed a correlation between CO2 production and mycotoxin accumulation. They also provide valuable information for the creation of a database focused on the development of a post-harvest decision support system to determine the relative risks of contamination with these mycotoxins in stored shelled peanuts.Item Open Access Comparative growth inhibition of bread spoilage fungi by different preservative concentrations using a rapid turbidimetric assay system(Frontiers, 2021-06-08) Valle Garcia, Marcelo; Garcia-Cela, Esther; Magan, Naresh; Venturini Copetti, Marina; Medina, AngelBread and intermediate moisture bakery products are mainly spoiled by yeasts and filamentous fungi. The inoculum load and preservation system used determines their shelf life. To extend the shelf life of such commodities, the use of chemical preservatives is the most common way to try and control the initiation of mold spoilage of bread. This study has utilized a rapid turbidimetric assay system (Bioscreen C) to examine the temporal efficacy of calcium propionate (CP) and potassium sorbate (PS) for controlling the growth of important bread spoilage fungi. The objectives were to compare the temporal growth of strains of three important spoilage fungi Hyphopichia burtonii (HB17), Paecilomyces variotii (PV11), and Penicillium roqueforti (PR06) isolated from visibly molded bread to (a) different concentrations of CP and PS (0–128 mM), (b) temperatures (25°C, 30°C), (c) water activity (aw; 0.95, 0.97), and (d) pH (5.0, 5.5). All three abiotic factors, pH, aw, and temperature, and preservative concentrations influenced the relative growth of the species examined. In general, PS was more effective than CP in inhibiting the growth of the strains of these three species. In addition, the Time to Detection (TTD) for the efficacy of the preservatives under the interacting abiotic factors was compared. The strain of Paecilomyces variotii (PV10) was the most tolerant to the preservatives, with the shortest TTD values for both preservatives. P. roqueforti was the most sensitive with the longest TTD values under all conditions examined. These results are discussed in the context of the evolution of resistance to food-grade preservatives by such spoilage fungi in bakery products.Item Open Access Comparison of growth and aflatoxin B1 production profiles of Aspergillus flavus strains on conventional and isogenic GM-maize-based nutritional matrices(Elsevier, 2021-10-30) Gasperini, Alessandra M.; Medina, Angel; Magan, NareshMaize grown in both North and South America are now predominantly genetically modified (GM) cultivars with some resistance to herbicide, pesticide, or both. There is little information on the relative colonisation and aflatoxin B1 (AFB1) production with maize meal-based nutritional matrices based on kernels of non-GM maize and isogenic GM-ones by strains of Aspergillus flavus. The objectives were to examine the effect of interacting conditions of temperature (25–35 °C) and water availability (0.99–0.90 water activity, aw) on (a) mycelial growth, (b) AFB1 production and (c) develop contour maps of optimum and marginal conditions of these parameters for four strains of A. flavus on three different non-GM and isogenic GM-maize based nutritional media. The growth of the four strains of A. flavus (three aflatoxigenic; one non-aflatoxigenic) was relatively similar in relation to the temperature × aw conditions examined on both non-GM and GM-based matrices. Optimum growth overall was at 30–35 °C and 0.99 aw for all four strains. Under water stress (0.90 aw) growth was optimum at 35 °C. Statistically: non-GM, GM cultivars, temperature and aw all significantly affected growth rates. For AFB1 production, all single and interacting factors were statistically significant except for non-GM × GM cultivar. In conclusion, colonisation of GM- and non-GM nutritional sources was similar for the different A. flavus strains examined. The contour maps will be very useful for understanding the ecological niches for both toxigenic and non-toxigenic strains in the context of the competitive exclusion of those producing aflatoxins.Item Open Access Comparison of multiple mycotoxins in harvested maize samples in three years (2018-2020) in four continents(Taylor and Francis, 2022-01-19) Raj, Jog; Farkaš, Hunor; Jakovčević, Zdenka; Medina, Angel; Magan, Naresh; Čepela, Robert; Vasiljević, MarkoThis study has examined the pattern of mycotoxin contamination of maize destined for animal feed in different global regions over a period of 3 years (2018–2020) with up to 1000+ samples analysed in each year. Overall, >75% of samples in each of the survey years were contaminated with multiple mycotoxins regardless of the global region (Europe, Africa, Asia, South Americas countries). Using LC-MS/MS, it was possible to quantify the relative contamination present in the samples in each year from the different regions of eight different mycotoxins including aflatoxin B1 (AFB1), ochratoxin A (OTA) deoxynivalenol (DON), fumonisin B1 (FB1) and B2, zearalenone (ZEA), T-2 and HT-2 toxins. The trends in mycotoxin contamination showed that there was a consistent contamination with DON in the 3 sampling years in all four regions. Interestingly, AFB1 contamination was prevalent in all regions in 2018, but more predominant in Europe and in 2019. In contrast, in 2020 it was found to be the major contaminant in Africa only. However, FB1 contamination of maize which was prevalent in Europe in 2018, became more prevalent in Asia and LATAM countries in 2019 and even in African maize in 2020. Comparisons of contamination with different mycotoxins in each of the years globally showed significant differences for AFB1, FB1, DON and ZEA between the different years. These results are discussed in relation to the trends of contamination of maize with mixtures of mycotoxins and the implication for their control in this key commodity used as an important ingredient in animal feed.Item Open Access Effect of acclimatization in elevated CO2 on growth and aflatoxin B1 production by Aspergillus flavus strains on pistachio nuts(MDPI, 2021-12-27) Baazeem, Alaa; Medina, Angel; Magan, NareshThere is little knowledge of the effect of acclimatization of Aspergillus flavus strains to climate-related abiotic factors and the subsequent effects on growth and aflatoxin B1 (AFB1) production. In this study, two strains of A. flavus (AB3, AB10) were acclimatized for five generations in elevated CO2 (1000 ppm × 37 °C) on a milled pistachio-based medium. A comparison was made of the effects of non-acclimatized strains and those that were acclimatized when colonizing layers of pistachio nuts exposed to 35 or 37 °C, 400 or 1000 ppm CO2, and 0.93 or 0.98 water activity (aw), respectively. Acclimatization influenced the fitness in terms of the growth of one strain, while there was no significant effect on the other strain when colonizing pistachio nuts. AFB1, production was significantly stimulated after ten days colonization when comparing the non-acclimatized and the acclimatized AB3 strain. However, there was no significant increase when comparing these for strain AB10. This suggests that there may be inter-strain differences in the effects of acclimatization and this could have a differential influence on the mycotoxin contamination of such commodities.Item Open Access Efficacy of different C18 HPLC analytical columns in the analysis of Fumonisins B1 and B2 in different matrices(Biointerface Research in Applied Chemistry, 2021-06-10) Sultan, Yousef; Magan, Naresh; Medina, AngelFumonisins B1 and B2 are carcinogenic and commonly contaminate corn and corn-based products. Analysis of such toxins using C18 HPLC column is officially accredited but still unknown if all column types can effectively separate FB1 and FB2 or not. The present study evaluated the efficiency of 5 analytical columns with different dimensions, particle sizes, and porosities to determine these toxins in both agar cultures of Fusarium verticillioides and cornflakes. Interestingly, the traditional column 150mm of length with 5µm porous particles had close retention times to those of the shortfused core column 75mm of length with 2.7 µm reflecting in time and solvents saving. Using Sep-Pack C18 for clean-up played an important role in enhancement the limit of quantification (LOQ) for cornflake samples (5-13.7 and 16.1-39 µg kg-1 for FB1 and FB2, respectively). However, it was relatively higher for fungal culture samples that were not passed through the cleaning-up step (11.5-16 and 28.1-46.3 µg kg-1 for FB1 and FB2, respectively). Overall, the lowest LOQ was obtained using the shorter fused core column. Finally, using such clean-up in the extraction of FB1 and FB2 from spiked cornflakes samples gave good recoveries (>80%) using all tested columns.Item Open Access Efficacy of metabolites of a Streptomyces strain (AS1) to control growth and mycotoxin production by Penicillium verrucosum, Fusarium verticillioides and Aspergillus fumigatus in culture(Springer, 2020-01-20) Mohd Danial, A.; Medina, Angel; Sulyok, M.; Magan, NareshThe objectives of this study were to determine the efficacy of metabolites of a Streptomyces strain AS1 on (a) spore germination, (b) mycelial growth, (c) control of mycotoxins produced by Penicillium verrucosum (ochratoxin A, OTA), Fusarium verticillioides (fumonisins, FUMs) and Aspergillus fumigatus (gliotoxin) and (d) identify the predominant metabolites involved in control. Initial screening showed that the Streptomyces AS1 strain was able to inhibit the mycelial growth of the three species at a distance, due to the release of secondary metabolites. A macroscopic screening system showed that the overall Index of Dominance against all three toxigenic fungi was inhibition at a distance. Subsequent studies showed that the metabolite mixture from the Streptomyces AS1 strain was very effective at inhibiting conidial germination of P. verrucosum, but less so against conidia of A. fumigatus and F. verticillioides. The efficacy was confirmed in studies on a conducive semi-solid YES medium in BioScreen C assays. Using the BioScreen C and the criteria of Time to Detection (TTD) at an OD = 0.1 showed good efficacy against P. verrucosum when treated with the Streptomyces AS1 extract at 0.95 and 0.99 water activity (aw) when compared to the other two species tested, indicating good efficacy. The effective dose for 50% control of growth (ED50) at 0.95 and 0.99 aw were approx. 0.005 ng/ml and 0.15 μg/ml, respectively, with the minimum inhibitory concentration (MIC) at both aw levels requiring > 40 μg/ml. In addition, OTA production was completely inhibited by 2.5 μg/ml AS1 extract at both aw levels in the in vitro assays. Ten metabolites were identified with four of these being predominant in concentrations > 2 μg/g dry weight biomass. These were identified as valinomycin, cyclo(L-Pro-L-Tyr), cyclo(L-Pro-L-Val) and brevianamide F.Item Open Access Efficacy of sodium metabisulphite for control of Aspergillus flavus and aflatoxin B1 contamination in vitro and in chilli powder and whole red chillies(Elsevier, 2021-12-29) Al-Jaza, Diyaa; Medina, Angel; Magan, NareshChillies are an important spice in many regions of the world. During the production and processing phases, they are prone to infection by mycotoxigenic fungi, especially Aspergillus Section Flavi species and contamination with aflatoxins. There is significant interest in controlling aflatoxin B1 (AFB1) contamination in such spices to ensure they remain below the legislative limits for human consumption. This study initially examined the potential efficacy of sodium metabisulphite (NaMBS, up to 5000 mg/L) for the control of growth and AFB1 production by Aspergillus flavus strains in vitro on a chilli-based medium modified to 0.93–0.995 water activity, aw). Subsequent studies examined efficacy of NaMBS in stored naturally contaminated chilli powder and whole red chillies, or when inoculated with A. flavus at 0.70, 0.80, 0.90, 0.95 aw and 30 °C for 20 days. NaMBS was effective in vitro in controlling growth of the three strains of A. flavus at the different aw levels examined. No growth occurred with >500–1250 NaMBS mg/L. AFB1 was only produced at 0.98 aw with complete inhibition at ≥1250 mg/L of the preservative at 30 °C. The in vitro ED50, ED90 for NaMBS varied with aw conditions. In situ studies with chilli powder and whole red dry chillies (naturally contaminated or + conidial inoculum of A. flavus) showed that at 0.70 and 0.80 aw, NaMBS treatments of 1000 and 2000 mg/L resulted in AFB1 contamination levels below the legislative limits for spices. However, under wetter conditions at 0.90 and 0.95 aw, AFB1 contamination of stored chilli powder, −/+ A. flavus inoculum, were above the legislative limits, even with 2000 mg/L NaMBS and 20 days storage at 30 °C. Stored whole chillies inoculated with A. flavus resulted in a reduction of populations, especially at 2000 mg/L NaMBS. Control of AFB1 was achieved only with 2000 mg/L NaMBS treatment after 10 and 20 days storage. Studies with commercial laminated sheets containing immobilised NaMBS with slow release of SO2 properties significantly reduced fungal populations and effectively controlled AFB1 contamination of the stored and packaged whole red chillies.Item Open Access Fungal diversity and metabolomic profiles in GM and isogenic non-GM maize cultivars from Brazil(Springer, 2020-10-12) Gasperini, A. M.; Garcia-Cela, Esther; Sulyok, M.; Medina, Angel; Magan, NareshThere is little knowledge of the microbial diversity, mycotoxins and associated secondary metabolites in GM maize and isogenic non-GM cultivars (cvs). This study has quantified the microbial populations and dominant fungal genera in 6 cvs of each type representative of herbicide, pesticide or stacked resistance to both. The predominant mycotoxins and targeted metabolomics profiles were also compared between the two sets of cvs. This showed that the overall fungal populations were 8.8 CFUs g−1 maize. The dominant genera, isolated from maize samples, whether surface-sterilised or not, in all maize cvs were Fusarium, followed by Penicillium, Aspergillus and occasionally Cladosporium and Alternaria. The analysis of the targeted metabolomics showed that approx. 29 different metabolites were detected. These were dominated by fumonisins and minor Penicillium spp. metabolites (questiomycin A and rugulovasine A). Interestingly, the range and number of mycotoxins present in the GM cvs were significantly lower than in the non-GM maize samples. This suggests that while the fungal diversity of the two types of maize appeared to be very similar, the major contaminant mycotoxins and range of toxic secondary metabolites were much lower in the GM cvs.Item Open Access Genome‐wide association mapping of Fusarium langsethiae infection and mycotoxin accumulation in oat (Avena sativa L.)(Wiley, 2020-06-08) Isidro-Sánchez, Julio; Cusack, Kane D’Arcy; Verheecke-Vaessen, Carol; Kahla, Amal; Bekele, Wubishet; Doohan, Fiona; Magan, Naresh; Medina, AngelFusarium langsethiae is a symptomless pathogen of oat panicles that produces T‐2 and HT‐2 mycotoxins, two of the most potent trichothecenes produced by Fusarium fungi in cereals. In the last few years, the levels of these mycotoxin in oat grain has increased and the European commission have already recommended a maximum level for of 1000 μg kg−1 for unprocessed oat for human consumption. The optimal and most sustainable way of combating infection and mycotoxin contamination is by releasing resistant oat varieties. Here the objective was to determine if we could identify any genomic loci associated with either the accumulation of F. langsethiae DNA or mycotoxins in the grain. In each of two years, field trials were conducted wherein 190 spring oat varieties were inoculated with a mixture of three isolate of the pathogen. Mycotoxins were quantified using liquid chromatography–tandem mass spectrometry. Varieties were genotyped using 16,863 genotyping by sequencing markers. Genome‐wide association studies associated 5 SNPs in the linkage group Mr06 with T‐2 + HT‐2 mycotoxin accumulation. Markers were highly correlated, and a single QTL was identified. The marker avgbs_6K_95238.1 mapped within genes showing similarity to lipase, lipase‐like or lipase precursor mRNA sequences and zinc‐finger proteins. These regions have previously been shown to confer a significant increase in resistance to Fusarium species.Item Open Access Impact of environmental conditions on the concentrations of trichothecenes, their glucosides, and emerging fusarium toxins in naturally contaminated, irradiated, and fusarium iangsethiae inoculated oats(MDPI, 2024-03-22) Oluwakayode, Abimbola; Greer, Brett; Meneely, Julie; Berthiller, Franz; Krska, Rudolf; Medina, AngelTrichothecenes produced by Fusarium species are commonly detected in oats. However, the ratios of the concentrations of free trichothecenes and their conjugates and how they are impacted by different interacting environmental conditions are not well documented. This study aims to examine the effect of water activity (0.95 and 0.98 aw) and temperature (20 and 25 °C) stress on the production of T-2 and HT-2 toxins, deoxynivalenol and their conjugates, as well as diacetoxyscirpenol (DAS). Multiple mycotoxins were detected using liquid chromatography–tandem mass spectrometry from 64 contaminated oat samples. The highest concentrations of HT-2-glucoside (HT-2-Glc) were observed at 0.98 aw and 20 °C, and were higher than other type A trichothecenes in the natural oats’ treatments. However, no statistical differences were found between the mean concentrations of HT-2-Glc and HT-2 toxins in all storage conditions analysed. DAS concentrations were generally low and highest at 0.95 aw and 20 °C, while deoxynivalenol-3-glucoside levels were highest at 0.98 aw and 20 °C in the naturally contaminated oats. Emerging mycotoxins such as beauvericin, moniliformin, and enniatins mostly increased with a rise in water activity and temperature in the naturally contaminated oats treatment. This study reinforces the importance of storage aw and temperature conditions in the high risk of free and modified toxin contamination of small cereal grains.Item Open Access Impact of predicted climate change environmental conditions on the growth of Fusarium asiaticum strains and mycotoxins production on a wheat-based matrix(Elsevier, 2024-03-13) Cervini, Carla; Naz, Naoreen; Verheecke-Vaessen, Carol; Medina, AngelFusarium asiaticum is a predominant fungal pathogen causing Fusarium Head Blight (FHB) in wheat and barley in China and is associated with approximately £201 million in annual losses due to grains contaminated with mycotoxins. F. asiaticum produces deoxynivalenol and zearalenone whose maximum limits in cereals and cereals-derived products have been established in different countries including the EU. Few studies are available on the ecophysiological behaviour of this fungal pathogen, but nothing is known about the impact of projected climate change scenarios on its growth and mycotoxin production. Therefore, this study aimed to examine the interacting effect of i) current and increased temperature (25 vs 30 °C), ii) drought stress variation (0.98 vs 0.95 water activity; aw) and iii) existing and predicted CO2 concentrations (400 vs 1000 ppm) on fungal growth and mycotoxin production (type B trichothecenes and zearalenone) by three F. asiaticum strains (CH024b, 82, 0982) on a wheat-based matrix after 10 days of incubation. The results showed that, when exposed to increased CO2 concentration (1000 ppm) there was a significant reduction of fungal growth compared to current concentration (400 ppm) both at 25 and 30 °C, especially at 0.95 aw. The multi-mycotoxin analysis performed by LC-MS/MS qTRAP showed a significant increase of deoxynivalenol and 15-acetyldeoxynivalenol production when the CH024b strain was exposed to elevated CO2 compared to current CO2 levels. Zearalenone production by the strain 0982 was significantly stimulated by mild water stress (0.95 aw) and increased CO2 concentration (1000 ppm) regardless of the temperature. Such results highlight that intraspecies variability exist among F. asiaticum strains with some mycotoxins likely to exceed current EU legislative limits under prospected climate change conditions.Item Open Access Impacts of gaseous ozone (O3) on germination, mycelial growth, and aflatoxin B1 production in vitro and in situ contamination of stored pistachio nuts(MDPI, 2022-06-17) Baazeem, Alaa; Medina, Angel; Magan, NareshPistachio nuts can become colonized by mycotoxigenic fungi, especially Aspergillus flavus, resulting in contamination with aflatoxins (AFs). We examined the effect of gaseous O3 (50–200 ppm; 30 min; 6 L/min) on (a) in vitro germination, (b) mycelial growth, and (c) aflatoxin B1 (AFB1) production on a milled pistachio nut-based medium at different water activity (aw) levels and at 30 °C. This was complimented with in situ studies exposing raw pistachio nuts to 50–200 ppm of O3. Exposure of conidia to gaseous O3 initially resulted in lower germination percentages at different aw levels. However, 12 h after treatment, conidial viability recovered with 100% germination after 24–48 h. Growth rates of mycelial colonies were slightly decreased with the increase of the O3 dose, with significant inhibition only at 0.98 aw. The production of AFB1 after O3 treatment and storage for 10 days was stimulated in A. flavus colonies at 0.98 aw. Raw pistachio nuts inoculated with A. flavus conidia prior to O3 exposure showed a significant decrease in population after 20 days of storage. However, AFB1 contamination was stimulated in most O3 treatments. The relationship between exposure concentration, time and prevailing aw levels on toxin control needs to be better understood for these nuts.Item Open Access Improvements within the peanut production chain to minimize aflatoxins contamination: an Ethiopian case study(Elsevier, 2021-10-15) Cervini, Carla; Verheecke-Vaessen, Carol; He, Tingting; Mohammed, Abdi; Magan, Naresh; Medina, AngelPeanuts (Arachis hypogaea L.) are a worldwide crop appreciated by consumers and known to have several health benefits (e.g. decreasing risk of cardiovascular diseases, lowering LDL cholesterol). Nonetheless, during the production chain, peanuts can be contaminated by mycotoxigenic fungi, especially Aspergillus flavus and A. parasiticus, responsible for contamination of this commodity with aflatoxins (AFs). Chronic exposure to these mycotoxins is known to have carcinogenic, teratogenic and immunosuppressive effects, while acute exposure can be fatal. Peanut-based products are considered the “new-gold” in Lower Middle-Income Countries (LMICs) as they are used to produce therapeutic food to fight malnutrition in children in the form of high energy bars (e.g. Plumpy’Nut®). The present study has been focused on an examination of the existing Ethiopian peanut supply chain to identify components that require improvements during pre-harvest, harvesting and post-harvest where practical and affordable intervention practices can be implemented. The lack of Good Agricultural Practices (GAPs), the use of traditional and rudimentary methods for drying and shelling peanuts, as well as inadequate storage locations are some of the main factors associated with the high contamination of Ethiopian peanuts with AFs. While control of AFs is complex, in-depth examination of existing practices has facilitated an overview of the potential for efficient and low-cost strategies to reduce and minimize these toxin risks in the Ethiopian peanut production chain. This includes the use of Drycard™ as a tool to check moisture content, the creation of homemade solar dryer and wooden nutcrackers, and the use of either the Purdue Improved Crop Storage (PICS) bags or novel bags with slow-release food-grade preservatives. The implementation of some of these approaches should ensure a safer home-grown peanut supply chain that would contribute to the growth of the economy of the country by reducing the high costs of importing such raw materials and supporting the use of local smallholder farmers peanuts. This would have significant economic benefits in the local peanut production chain.Item Open Access Interacting abiotic factors affect growth and aflatoxin B1 production profiles of Aspergillus flavus strains on pistachio-based matrices and pistachio nuts(Frontiers Media, 2021-01-20) Baazeem, Alaa; Garcia-Cela, Esther; Medina, Angel; Magan, NareshPistachio nuts are an economically important commodity produced by many countries. They can be colonized by mycotoxigenic fungi, especially Aspergillus flavus, resulting in contamination with aflatoxins (AFs), especially aflatoxin B1 (AFB1), a Class 1a carcinogen. The objectives were to examine the effect of interactions between the two key abiotic factors, temperature and water activity (aw) on (a) in vitro growth and AFB1 production by four strains of A. flavus isolated from pistachio nuts, on a milled pistachio nut medium modified ionically (NaCl) and non-ionically (glycerol) in the range 20–35°C and 0.995–0.85 aw, (b) colonization of layers of raw pistachio nuts stored at different interacting temperature x aw conditions and on relative AFB1 production and (c) develop models to produce contour maps of the optimal and marginal boundary conditions for growth and AFB1 production by up to 4 strains of this species. On pistachio nut-based media, optimum growth of four strains of A. flavus was at 0.98–0.95 aw and 30–35°C. Optimum AFB1 production was at 30–35°C and 0.98 aw. No significant differences in growth was found on ionic and non-ionically modified media. Colonization of layers of raw pistachio nuts was slower and contamination with AFB1 significantly less than in in vitro studies. Contour maps based on the pooled data for up to four strains (in vitro, in situ) showed the optimum and marginal conditions for growth and AFB1 production. These data can be used to identify those conditions which represent a high, intermediate or low risk of colonization and AFB1 contamination in the pistachio nut processing chain. These results are discussed in the context of the development of appropriate intervention strategies to minimize AFB1 contamination of this economically important commodity.