Mycotoxin-producing Potential Research Articles

The Sorghum Grain Mold Disease Complex: Pathogens, Host Responses, and the Bioactive Metabolites at Play.

Grain mold is a major concern in sorghum [Sorghum bicolor (L.) Moench] production systems, threatening grain quality, safety, and nutritional value as both human food and livestock feed. The crop’s nutritional value, environmental resilience, and economic promise poise sorghum for increased acreage, especially in light of the growing pressures of climate change on global food systems. In order to fully take advantage of this potential, sorghum improvement efforts and production systems must be proactive in managing the sorghum grain mold disease complex, which not only jeopardizes agricultural productivity and profitability, but is also the culprit of harmful mycotoxins that warrant substantial public health concern. The robust scholarly literature from the 1980s to the early 2000s yielded valuable insights and key comprehensive reviews of the grain mold disease complex. Nevertheless, there remains a substantial gap in understanding the complex multi-organismal dynamics that underpin the plant-pathogen interactions involved – a gap that must be filled in order to deliver improved germplasm that is not only capable of withstanding the pressures of climate change, but also wields robust resistance to disease and mycotoxin accumulation. The present review seeks to provide an updated perspective of the sorghum grain mold disease complex, bolstered by recent advances in the understanding of the genetic and the biochemical interactions among the fungal pathogens, their corresponding mycotoxins, and the sorghum host. Critical components of the sorghum grain mold disease complex are summarized in narrative format to consolidate a collection of important concepts: (1) the current state of sorghum grain mold in research and production systems; (2) overview of the individual pathogens that contribute to the grain mold complex; (3) the mycotoxin-producing potential of these pathogens on sorghum and other substrates; and (4) a systems biology approach to the understanding of host responses.

An investigation of fungal contamination on the surface of medicinal herbs in China

BackgroundThe dried parts of medicinal herbs are susceptible to the infection of fungi during pre- or post-harvest procedure. This study aimed to investigate the presence of fungi and their metabolites mycotoxins on the surface of medicinal herbs collected from China.MethodsForty-five retail samples of 15 different medicinal herbs were collected from 3 different regions in China. Then the potential fungi were immediately washed off from the surface of each sample with 0.1% Tween-20 followed by incubation of the rinse on petri-dish with potato dextrose agar containing chloramphenicol at 28 °C. The obtained fungi were isolated as single colonies and then characterized by morphology and molecular identification using internal transcribed spacer (ITS) sequencing with extracted DNA. Meanwhile, the mycotoxin-producing potential of the isolates was studied by liquid chromatography-tandem mass spectrometry (LC-MS/MS).ResultsA total of 126 fungi were identified from the surface of samples by morphology and ITS sequencing, with Aspergillus and Penicillium genera as the predominant contaminants. The mycotoxin-producing potential analysis showed that 6 of 8 A. versicolor isolates could produce sterigmatocystin. All 3 A. aculeatus isolates produced ochratoxin A, but only 1 of 3 A. flavus strains produced aflatoxins B1 and B2 without G1 and G2. Although the sample contamination ratios were high (≥95.6%), there was no significant difference (χ2 = 1.05, P = 1.0) among the samples from 3 regions, which demonstrates the prevalent fungal contamination in the herbal medicines.ConclusionThe prevalent contamination phenomenon of fungi and high potential risk of sterigmatocystin and ochratoxin A were observed in 45 medicinal herbs collected from China.

Utility of the phylotoxigenic relationships among trichothecene-producing Fusarium species for predicting their mycotoxin-producing potential

Species of the genus Fusarium are well-known plant pathogens and mycotoxigenic fusaria are associated with health hazards to humans and animals. There is a need to understand the mechanisms of mycotoxin production by Fusarium species and to predict which produce mycotoxins. In this study, the Fusarium phylogenetic tree was first inferred among trichothecene producers and related species. We reconstructed the maximum likelihood (ML) tree based on the combined data from nucleotide sequences of rDNA cluster regions, the β-tubulin gene (β-tub) and the elongation factor 1α gene (EF-1α). Second, based on this tree topology, the ancestral states of the producing potential of type A and B trichothecenes (TriA and TriB), zearalenone (ZEN), moniliformin (MON), beauvericin (BEA) and enniatins (ENN) were reconstructed using the maximum parsimony (MP) method based on the observed production by extant species as reported in the literature. Finally, the species having the potential to produce each of these six mycotoxins was predicted on the basis of the parsimonious analysis. The ML tree indicated that the Fusarium species analysed in this study could be divided into two major clades. Clade I was divided into four distinct subclades: I-a, I-b, I-c and I-d. Furthermore, the parsimony reconstruction suggested that the potential for producing MON and ZEN was gained or lost only once, and that the producing potential for TriA and TriB, BEA and ENN was repeatedly gained and lost during the evolutionary history of the Fusarium species analysed in this study. Interestingly, the results showed the possibility that several species, about which reports were scarce with regard to mycotoxin production, have the potential to produce one or more of the six evaluated in this study. The phylogenetic information therefore helps one to predict the mycotoxin-producing potential by Fusarium species, and these “phylotoxigenic relationships” may be useful for predicting the pathogenicity of fungi.

Species-specific fungal DNA in airborne dust as surrogate for occupational mycotoxin exposure?

Possible health risks associated with occupational inhalation of mycotoxin-containing dust remain largely unknown, partly because methods for mycotoxin detection are not sensitive enough for the small dust masses obtained by personal sampling, which is needed for inhalable exposure measurements. Specific and sensitive PCR detection of fungi with mycotoxin-producing potential seem to be a good surrogate for occupational exposure measurements that include all fungal structures independent of morphology and cultivability. Results should, however, be interpreted with caution due to variable correlations with mycotoxin concentrations.

Mycotoxin-producing potential of fungi associated with qat (Catha edulis) leaves in Yemen.

Forty-four fungal species belonging to 20 genera were isolated from 30 samples of qat leaves. The most frequent genera were Aspergillus, Alternaria, Penicillium, and Cladosporium followed by Fusarium, Drechslera, Chaetomium, and Mucor. The most prevalent species in above genera were Aspergillus niger, A. flavus, A fumigatus, Alternaria alternata, Penicillium chrysogenum, P. citrinum, Cladosporium cladosporioides, and Fusarium verticillioides. From these fungi, 17 species (39%) related to 7 genera (35%) proved to be true endophytes. Eleven out of 75 isolates were mycotoxigenic. A. alternata produced alternariol and alternariol monomethyl ether whereas A. flavus produced aflatoxins B1 and B2. Ochratoxin A, sterigmatocystin, citrinin and T-2 toxin were produced by A. ochraceus, A. versicolor, P. citrinum and F. oxysporum, respectively. The presence of such toxigenic fungi associated with qat leaves is considered to be a threat to public health.

Mycotoxin-producing potential of fungi isolated from amaranth seeds in Argentina

To evaluate the potential for mycotoxin production by molds in amaranth grains, the mycoflora was determined both before and after surface disinfection on dichloran-chlor-amphenicol-peptone agar (DCPA) and dichloran-18% glycerol agar (DG18). On both media Aspergillus, Penicillium, Fusarium and Alternaria were the predominant genera. A. flavus and A. parasiticus were the Aspergillus species most frequently isolated. P. chrysogenum was the species most common among the penicillia. F. equiseti was the predominant Fusarium species. Isolates of Aspergillus, Penicillium and Fusarium were screened for mycotoxin production on sterile rice substrate and also using a simple screening method. Toxinogenic strains of A. flavus and A. parasiticus (aflatoxins), A. versicolor (sterigmatocystin), P. citrinum (citrinin), P. viridicatum (penicillic acid), F. moniliforme, F. equiseti and F. semitectum (zearalenone), were encountered. The simple screening method for toxinogenic molds showed good performance for the detection of molds producing aflatoxins and zearalenone compared with mycotoxins production on the natural substrate.

Enzymatic activity and mycotoxin-producing potential of fungi isolated from rotted lemons

Enzymatic activity and mycotoxin-producing potential of fungi isolated from rotted lemons

Mycotoxins and mycotoxigenic moulds in nuts and sunflower seeds for human consumption

A survey was carried out to obtain data on the occurrence of mycotoxins and the mycotoxin-producing potential of fungi isolated from nuts (almonds, peanuts, hazelnuts, pistachio nuts) and sunflower seeds in Spain. Thin-layer chromatography was used to separate the toxins. Aflatoxins were detected in one sample of almonds (95 ppb aflatoxin B1 and 15 ppb aflatoxin B2) and in one sample of peanuts at a level below 10 ppb of aflatoxin B1. 100% of samples showed variable incidence of fungal contamination. The predominant fungi present in samples were Penicillium spp, Aspergillus niger, A. flavus, A. glaucus and Rhizopus spp. The results showed that isolates of different species were able to produce aflatoxins B1, B2, G1, and G2, sterigmatocystin, ochratoxin A, patulin, citrinin, penicillic acid, zearalenone, and griseofulvin.

Mycotoxin-producing potential of fungi isolated from red kidney beans.

The predominant fungi present in samples of reject and retail red kidney beans were Aspergillus glaucus, Penicillium spp. and Alternaria spp. Together with A. ochraceus, A. flavus, Fusarium spp., and Trichoderma, these isolates from the reject beans were screened for numerous mycotoxins by TLC. The most consistently produced mycotoxins were penicillic acid (from A. ochraceus and Penicillium spp.) and Alternaria toxins (tenuazonic acid and alternariol). A. glaucus strains were tested for cytotoxicity in three tissue culture cell lines with positive results.

Zearalenone in New Zealand pasture herbage and the mycotoxin-producing potential ofFusariumspecies from pasture

Abstract Zearalenone, in concentrations of 0.4 — 4.0 mg/kg dry weight of herbage, was found in 10 of 60 pasture samples collected from January to April 1985 at sites near Pukekohe, Wanganui, and Gisborne. It was present most often and in highest concentrations in samples from a Gisborne coastal farm. Zearalenone was produced in culture by some strains of eight of the Fusarium spp. most often recovered from the samples, but most consistently and in greatest amounts by F. crookwellense and F. culmorum. There was no correlation between zearalenone concentrations in the samples and Fusarium numbers, as determined by direct counts of macroconidia and by dilution plating. There was also no correlation between zearalenone concentrations and the in vitro zearalenone-producing potential of the Fusarium spp. recovered. Site-related factors appeared to affect zearalenone concentrations as much as the presence of Fusarium spp. Cytotoxicity of the Fusarium cultures to HEp2 cells in tissue culture, indicative of the pr...

Public Health Significance of Molds and Mycotoxins in Fermented Dairy Products

Mold growth on cheese and other fermented dairy products is a common and recurring problem. Potential mycotoxin contamination is serious since some molds can grow and produce mycotoxins at temperatures as low as −2 to 10°C. Work can be divided into: 1) incidence, types, and mycotoxin-producing potential of molds in fermented dairy products, 2) experimental mycotoxin production on cheese under conditions of storage and aging of cheese, 3) natural occurrence of mycotoxins in commercial samples of cheese, and 4) potential toxicity of Penicillium roqueforti and its significance in blue veined cheeses.Molds most common on cheese and fermented dairy products are Penicillium species. Mycotoxins produced by these organisms are penicillic acid, patulin, ochratoxin A, and citrinin. Percentages of molds in cheese capable of producing some commonly studied mycotoxins ranged from 1.8% to 12.4%. Cheese is an excellent substrate for mold growth but a poor substrate for mycotoxin production. Several natural occurrences of mycotoxins in cheese include small and variable amounts of patulin, penicillic acid, sterigmatocystin (600µg/kg), penitrem A, and mycophenolic acid. Penicillium roqueforti is capable of producing toxic alkaloids and other compounds. The significance of these substances for human health is unclear.The decision to trim or to discard moldy cheese can be aided by considering the risk versus benefit based on storage history (temperature), extent of mold growth, appearance of mold (color), and size of cheese.

Fungal contamination and mycotoxin-producing potential of dried beans.

A total of 604 samples of about 7 different types of beans was examined to determine their mycological profiles, and suitability for use as solid substrates for mycotoxin production. All of the samples were collected from bean jam makers in Tokyo by the official food examiners. Genera Penicillium and Aspergillus were predominant, and genus Wallemia was also found commonly in all types of beans. Mycotoxin-producing Aspergillus strains were isolated from 52 samples of beans, approximately 9% of the total. The highest incidence of toxigenic Aspergillus (14.1%) was found in kidney beans. Red beans and peas inoculated with Aspergillus ochraceus were found to produce about 7 to 8 times more toxin than was obtained in a liquid medium. and red beans inoculated with A. versicolor produced more toxin than was obtained in yeast extract sucrose broth. Green peas inoculated with Fusarium graminearum produced about 8 times more T-2 toxin than was obtained in 1% peptone containing Czapek solution under comparable culture conditions.

Mycotoxin producing potential of fungi associated with dry shrimps.

Among 114 fungi isolated from 20 dry shrimp samples, 27 isolates were capable of producing mycotoxins. Aspergillus and Penicillium were‐the‐predominant fungi. Two of 3 Aspergillus flavus could produce aflatoxin B1 and G1 on yeast extract sucrose medium and on surface sterilized dry shrimps. For other toxigenic species, toxicity was found mostly in the chloroform extracts of cultures. Visibly mouldy dry shrimps had significantly higher moisture content than the non‐mouldy ones. Most of the fungi were isolated from mouldy samples.