Triazole Fungicide Residues and Their Inhibitory Effect on Some Trichothecenes Mycotoxin Excretion in Wheat Grains.

Wheat is one of the global strategic crops and ranks third in terms of cereals production. Wheat crops are exposed to many fungal infections during their cultivation stages, some of which have the ability to secrete a number of toxic secondary metabolites that threaten the quality of the grains, consumer health, producer economics, and global trade exchange. Fifty-four random samples were collected from wheat which originated from different countries. The samples included 14 types of soft wheat to study the extent of their contamination with deoxynivalenol (DON) and T-2 toxin by auto-ELISA technology and r-biopharm microtiter plate. All samples were contaminated with DON toxin except one sample, and the values ranged between 40.7 and 1018.8 µg/kg-1. The highest contamination rates were in Lithuanian wheat and the lowest was in Indian wheat. Meanwhile, the highest average level of T-2 toxin contamination was in Lithuanian wheat grains with 377.4 µg/kg-1, and the lowest average was 115.3 µg/kg-1 in Polish wheat. GC-MS/MS and multiple reaction monitoring mode (MRM) were used to detect 15 triazole derivatives in the collected samples, which may be used to combat fungal diseases on wheat during the growing season. Only 9 derivatives were found: simeconazole, penconazole, hexaconazole, cyproconazole, diniconazole, tebuconazole, metconazole, fenbuconazole, and difenoconazole. These derivatives varied according to the origin of the wheat samples as well as their concentration, whereas another 6 derivatives were not detected in any samples. A direct inverse relationship was found between the DON concentration in the samples and the residues of simeconazole, penconazole, diniconazole, tebuconazole, metconazole, fenbuconazole, and difenoconazole, and the T-2 toxin showed the same relationship except for tebuconazole. The safe and rational use of some triazole derivatives may be a new approach and a promising strategy to not only reduce plant diseases and their problems, but also to get rid of some mycotoxins as grain contaminants.

Development and validation of a high-performance liquid chromatography method with post-column derivatization for the detection of aflatoxins in cereals and grains.

A novel, reliable and rapid high-performance liquid chromatography (HPLC) method with post-column derivatization was developed and validated. The HPLC method was used for the simultaneous determination of aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) in various cereals and grains. Samples were extracted with 80:20 (v/v) methanol:water and purified using C18 (40-63 µm) solid-phase extraction cartridges. AFs were separated using a LiChroCART-RP-18 (5 µm, 250 × 4.0 mm(2)) column. The mobile phase consisted of methanol:acetonitrile:buffer (17.5:17.5:65 v/v) (pH 7.4) delivered at the flow rate of 1.0 mL min(-1) The fluorescence of each AF was detected at λex = 365 nm and λem = 435 nm. All four AFs were properly resolved within the total run time of 20 min. The established method was extensively validated as a final verification of the method development by the evaluation of selectivity (AFB1, AFB2, AFG1 and AFG2), linearity (R(2) ≥ 0.9994), precision (average SD ≤ 2.79), accuracy (relative mean error ≤ -5.51), robustness (p < 0.0080), ruggedness (p < 0.0100) and average recoveries (89.2-97.8%). The limits of quantification of AFB1, AFB2, AFG1 and AFG2 were 0.080, 0.073, 0.062 and 0.066 ng g(-1), respectively. Finally, the developed method was applied for the analysis of AFs in 45 samples comprising rice (n = 20), wheat (n = 15) and maize (n = 10). The results showed that 65% of rice, 20% of wheat and 80% of maize samples were found contaminated with AFs. Thus, according to the achieved results, it is suggested that the newly developed HPLC method could be effectively applied for the routine analysis of the AFs in different cereals and grains.

Whole Grains, Dietary Fibers and the Human Gut Microbiota: A Systematic Review of Existing Literature.

BACKGROUND: The health benefits of dietary fibers have been proved for a long time. The importance of microbiota has been identified in human health and there is a growing interest to study the factors affecting it. OBJECTIVE: This systematic review aimed to investigate the impact of fiber and whole grains (WGs) on human gut microbiota in a patent-based review. METHODS: All related clinical trials were systematically searched on PubMed and Scopus search engines from inception up to Feb 2020. Interventional human studies reporting changes in microbiota by using any type of grains/fibers were included. The following information was extracted: date of the publication, location and design of the study, sample size, study population, demographic characteristics, the amount of dietary WGs/fiber, the duration of intervention, the types of grains or fibers, and changes in the composition of the microbiota. RESULTS: Of 138 studies which were verified, 35 studies with an overall population of 1080 participants, met the inclusion criteria and entered the systematic review. The results of interventional trials included in this review suggest some beneficial effects of consuming different amounts and types of WGs and fibers on the composition of intestinal microbiota. Most included studies showed that the intake of WGs and fibers increases bifidobacteria and lactobacilli and reduces the pathogenic bacteria, such as Escherichia coli and clostridia in the human gut. CONCLUSION: The consumption of WGs/fibers may modify the intestinal microbiota and promote the growth of bifidobacteria and lactobacilli. Nevertheless, further research is warranted in different populations and pathological conditions.

Diversity of thermophilic and thermotolerant fungi in corn grain.

Corn bins in the midwestern United States can reach temperatures up to 52 C. High temperatures combined with sufficient moisture and humidity in bins provide the perfect environment to promote the growth of thermophilic and thermotolerant fungi. In this article, we characterize for the first time thermophilic and thermotolerant fungi in corn grain bins using culture-based methods and pyrosequencing techniques. Corn samples were collected from local farms in western Illinois. Samples were plated and incubated at 50 C using a variety of approaches. Of several hundred kernels examined, more than 90% showed colonization. Species identified using culture methods included Thermomyces lanuginosus, Thermomyces dupontii, Aspergillus fumigatus, Thermoascus crustaceus, and Rhizomucor pusillus. Pyrosequencing was also performed directly on corn grain using fungal-specific primers to determine whether thermophilic fungi could be detected using this technique. Sequences were dominated by pathogenic fungi, and thermophiles were represented by less than 2% of the sequences despite being isolated from 90% of the grain samples using culturing techniques. The high abundance of previously undocumented viable fungi in corn could have negative implications for grain quality and pose a potential risk for workers and consumers of corn-derived products in the food industry. Members of the Sordariales were absent among thermophile isolates and were not represented in nuc rDNA internal transcribed spacer (ITS) sequences. This is in striking contrast with results obtained with other substrates such as litter, dung, and soils, where mesophilic and thermophilic members of the Sordariaceae and Chaetomiaceae are common. This absence appears to reflect an important difference between the ecology of Sordariales and other orders within the Ascomycota in terms of their ability to compete in microhabitats rich in sugars and living tissues.

Detection of Tilletia caries, Tilletia laevis and Tilletia controversa wheat grain contamination using loop-mediated isothermal DNA amplification (LAMP).

The study describes a novel diagnostic protocol based on a loop-mediated isothermal DNA amplification (LAMP) for identification of wheat grains infection by Tilletia laevis, Tilletia caries (common bunt) and Tilletia controversa (draft bunt). The presented data showed that the LAMP analysis is a simple, specific and rapid method that could be used for detection of Tilletia spp. in contaminated grain samples. The lowest DNA concentration required for the successful detection of Tilletia spp. strains were estimated to be 0.001 ng/µl. Simultaneously the detection limit for wheat grain contamination by T. caries and T. laevis teliospores was estimated at 20 µg per 100 g of grain. For T. controversa detection limit was lower and was approximately 20 mg of teliospores per 100 g of grain. The negative results of the LAMP reactions were achieved for the most common fungal species colonizing wheat grain like Fusarium spp., Alternaria sp., Cladosporium sp., Helminthosporium sp., and Penicillium sp.

Possibility of Alternaria toxins reduction by extrusion processing of whole wheat flour.

This study represents the first report about possibility of reduction of Alternaria toxins in wheat using the extrusion process. Effects of extrusion processing parameters - moisture content (w=16, 20, 24g/100g), feeding rate (q=15, 20, 25kg/h), and screw speed (v=300, 390, 480rpm), on reduction rate of tenuazonic acid (TeA), alternariol (AOH) and alternariol monomethyl ether (AME), in whole wheat flour were investigated. Temperature ranged between 111.1 and 160.8°C, while the absolute pressure was from 0.17 to 0.23MPa. The simultaneous influence of w and v was the most important for TeA reduction (p<0.05), while v and q were the most influential for AOH reduction (p<0.01). Level of AME reduction was mostly influenced by w and v (p<0.10). Optimal parameters for reduction of all three Alternaria toxins were as follows: w=24g/100g, q=25kg/h, v=390rpm, with a reduction of 65.6% for TeA, 87.9% for AOH and 94.5% for AME.

Endophytic bacteria from wheat grain as biocontrol agents of Fusarium graminearum and deoxynivalenol production in wheat.

In Uruguay, Fusarium graminearum is the most common species that infects wheat and is responsible for Fusarium head blight (FHB) and contamination of grain with deoxynivalenol (DON). The aim of this work was to select bacterial endophytes isolated from wheat grain to evaluate their antagonistic ability against F. graminearum and DON production in vitro and under field conditions. Four strains identified as Bacillus megaterium (BM1) and Bacillus subtilis (BS43, BSM0 y BSM2) significantly reduced fungal growth and spore germination of F. graminearum. This antagonist activity remained unchanged after the bacterial cultures were heat treated. Under field conditions, treatments with antagonist BM1 was the most effective, reducing the FHB incidence and severity by 93 and 54 %, respectively, and the production of DON by 89.3 %.

Amino acid-derived betaines dominate as urinary markers for rye bran intake in mice fed high-fat diet--A nontargeted metabolomics study.

SCOPE: Bioprocessing of whole grain cereals may affect the bioavailability of phytochemicals associated with grain fiber and ultimately lead to different health outcomes. Here, we studied the impact of long-term feeding with intact and bioprocessed rye bran on the urinary phytochemical profile of mice. METHODS AND RESULTS: Nontargeted hydrophilic interaction chromatography-ESI-qTOF-MS metabolite profiling approach was applied on urine samples collected from three groups of diet-induced obese mice fed for 8 weeks with one of the three diets: high-fat (HF) control diet, HF diet enriched with intact rye bran, or HF diet enriched with bioprocessed rye bran. The most striking finding was the increased urinary excretion of several amino-acid derived betaines after both rye diets. These included proline betaine, alanine betaine, valine betaine, phenylalanine betaine, pipecolic acid betaine, and trigonelline, but not glycine betaine. Furthermore, bioprocessing may have improved the bioavailability of rye-derived phytochemicals, as higher increase in, e.g. ferulic acid and benzoxazinoid metabolites were observed in urine of mice fed with bioprocessed than intact rye bran. CONCLUSION: Urinary excretion of various betaines was greatly increased in mice fed rye brans. Furthermore, bioprocessing of rye bran appears to serve as a beneficial way to improve the bioavailability of various phytochemicals.