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1.
J Sci Food Agric ; 100(3): 1004-1011, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31646639

RESUMO

BACKGROUND: Barley (Hordeum vulgare L.) is one of the most important cereals worldwide, and its quality is affected by fungal contamination such as species of the genus Alternaria. No information is available about the occurrence of Alternaria mycotoxins in Argentinean barley grains, which is of concern, because they can be transferred into malt and beer. The aim of this study was to analyze the occurrence of alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TeA) in malting barley grains from the main producing region of Argentina during the 2014 and 2015 growing seasons. RESULTS: The most frequent mycotoxin was AOH (64%), which was detected at higher levels (712 µg kg-1 ) compared with other studies, followed by TeA (37%, 1522 µg kg-1 ), while AME was present in five samples in the 2015 growing season only, with a mean of 4876 µg kg-1 . A similar frequency of mycotoxin occurrence was observed in both years (80.8 vs 85.3%), but more diverse contamination was found in 2015, which was characterized by lower accumulated precipitation. Nevertheless, AOH was more frequently found in 2014 than in 2015 (80.8 and 47.1% respectively). A negative correlation between AOH concentration and temperature was observed. The susceptibility of different barley varieties to mycotoxin accumulation varied with the mycotoxin, geographical location and meteorological conditions. CONCLUSION: The results obtained in the present work represent a tool for risk assessment of exposition to these mycotoxins and could be used by food safety authorities to determine the need for their regulation. Furthermore, the establishment of a hazard analysis and critical control point (HACCP) system to minimize fungal and mycotoxin contamination in barley from farm to processing could be apply to ensure food safety. © 2019 Society of Chemical Industry.


Assuntos
Alternaria/metabolismo , Hordeum/microbiologia , Micotoxinas/análise , Argentina , Contaminação de Alimentos/análise , Manipulação de Alimentos , Hordeum/química , Lactonas/análise , Micotoxinas/metabolismo , Sementes/química , Sementes/microbiologia
3.
J Sci Food Agric ; 100(2): 863-873, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31646638

RESUMO

BACKGROUND: Wheat is the most important winter crop in the world, being affected by the presence of fungal, mainly those belonging to the Fusarium genus. Fusarium head blight (FHB) is a serious disease that causes important economic damage and quantitative/qualitative losses, with Fusarium graminearum and Fusarium poae being two of the most isolated species worldwide. The present study aimed to evaluate the interaction between F. graminearum and F. poae and the effects on disease parameters, grain quality and mycotoxin contamination on five wheat genotypes under field conditions during three growing seasons. RESULTS: Statistical differences between Fusarium treatments were found for disease parameters, grain quality and mycotoxin contamination during the 2014/2015 growing season. High values of incidence (58.00 ± 8.00%), severity (6.28 ± 1.51%) and FHB index (4.72 ± 1.35) were observed for F. graminearum + F. poae treatment. Regarding grain quality, the results showed that the degradation of different protein fractions depends on each Fusarium species: glutenins were degraded preferably by F. graminearum (-70.82%), gliadins were degraded preferably by F. poae (-29.42%), whereas both protein fractions were degraded when both Fusarium species were present (-60.91% and -16.51%, respectively). Significant differences were observed for mycotoxin contamination between genotypes, with Proteo being the most affected (DON = 12.01 ± 3.67 µg g-1 ). In addition, we report that 3-ADON predominated over 15-ADON in the three seasons evaluated. CONCLUSION: Variations in plant-pathogen interaction (Fusarium-wheat pathosystem) should be considered at least in years with favorable climatic conditions for FHB development, as a result of the potential impact of this disease on grain quality and mycotoxin contamination. © 2019 Society of Chemical Industry.


Assuntos
Fusarium/metabolismo , Micotoxinas/análise , Doenças das Plantas/microbiologia , Triticum/química , Triticum/microbiologia , Fusarium/classificação , Micotoxinas/metabolismo , Estações do Ano , Sementes/química , Sementes/microbiologia
4.
Food Chem ; 311: 125975, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31855777

RESUMO

A modified quick, easy, cheap, effective, rugged, and safe method coupled with ultra-high performance liquid chromatography-tandem mass spectrometry was established for the simultaneous detection of five Alternaria toxins (tenuazonic acid, alternariol, alternariol monomethyl ether, altenuene, and tentoxin) in wolfberry. The sample pretreatment conditions including the dilution solvent, the extraction solvent and the QuEChERS purification parameters were optimized. Detection of the five Alternaria toxins was performed in MRM mode under ESI + conditions. The results showed that the five Alternaria toxins exhibitedgood linearity (1-200 µg/L, with correlation coefficients > 0.999). The limits of detection were 0.07-0.24 µg/kg, and the limits of quantification were 0.32-0.77 µg/kg. The trueness was between 73.8% and 111.5%, and the precision was lower than 10%. The established method was effectively used for the determination of five Alternaria toxins in 155 wolfberry samples from Northwest China.


Assuntos
Alternaria/metabolismo , Lycium/microbiologia , Micotoxinas/análise , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida de Alta Pressão , Lactonas/análise , Lactonas/isolamento & purificação , Limite de Detecção , Micotoxinas/isolamento & purificação , Micotoxinas/metabolismo , Peptídeos Cíclicos/análise , Peptídeos Cíclicos/isolamento & purificação , Reprodutibilidade dos Testes , Ácido Tenuazônico/análise , Ácido Tenuazônico/isolamento & purificação
5.
J Appl Microbiol ; 128(1): 242-254, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31559664

RESUMO

AIMS: To study the antimicrobial agents of the Bacillus velezensis strain HC6 and assess the application potential of B. velezensis HC6 in maize. METHODS AND RESULTS: We applied a dual culture technique to test the antimicrobial activity of B. velezensis HC6 against bacteria and fungi of common contaminated crops. Bacillus velezensis HC6 showed antagonistic action on pathogenic fungi, including Aspergillus and Fusarium, as well as pathogenic bacteria (especially Listeria monocytogenes). When applied in maize, B. velezensis HC6 could also inhibit the growth of multiple pathogenic fungi and reduce their production of aflatoxin and ochratoxin. Three kinds of antimicrobial lipopeptides, including iturin, fengycin and surfactin were identified in B. velezensis HC6 culture supernatant by high-performance liquid chromatography and MALDI-TOF mass spectrometry. Iturin and fengycin showed obvious antimicrobial activity to the tested fungal strains. CONCLUSIONS: Bacillus velezensis HC6 produces three kinds of lipopeptides which showed antimicrobial activity against several common pathogenic fungi and bacteria. Bacillus velezensis HC6 is potential to be biocontrol bacteria in maize. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacillus velezensis HC6 shows obvious antimicrobial activity to important crops pathogenic fungi which usually produce mycotoxins that are harmful to animal and human health. We demonstrate that three different types of lipopeptides produced by B. velezensis contributed to the antimicrobial activity. Bacillus velezensis HC6 has the potential to be effective biocontrol agent in crops.


Assuntos
Anti-Infecciosos , Bacillus/fisiologia , Agentes de Controle Biológico , Lipopeptídeos/metabolismo , Zea mays/microbiologia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Bacillus/química , Bactérias/efeitos dos fármacos , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Fungos/metabolismo , Lipopeptídeos/química , Lipopeptídeos/farmacologia , Micotoxinas/metabolismo , Doenças das Plantas/microbiologia
6.
Chemosphere ; 240: 124948, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31726616

RESUMO

Zearalenone is a xenoestrogenic mycotoxin produced by Fusarium species. High exposure with zearalenone induces reproductive disorders worldwide. Cyclodextrins are ring-shaped host molecules built up from glucose units. The apolar cavity of cyclodextrins can entrap so-called guest molecules. The formation of highly stable host-guest type complexes with cyclodextrins can decrease the biological effect of the guest molecule. Therefore, cyclodextrins may be suitable to decrease the toxicity of some xenobiotics even after the exposure. In this study, the protective effect of beta-cyclodextrins against zearalenone-induced toxicity was investigated in HeLa cells and zebrafish embryos. Fluorescence spectroscopic studies demonstrated the formation of stable complexes of zearalenone with sulfobutyl-, methyl-, and succinyl-methyl-substituted beta-cyclodextrins at pH 7.4 (K = 1.4-4.7 × 104 L/mol). These chemically modified cyclodextrins considerably decreased or even abolished the zearalenone-induced loss of cell viability in HeLa cells and mortality in zebrafish embryos. Furthermore, the sublethal effects of zearalenone were also significantly alleviated by the co-treatment with beta-cyclodextrins. To test the estrogenic effect of the mycotoxin, a transgenic bioindicator zebrafish model (Tg(vtg1:mCherry)) was also applied. Our results suggest that the zearalenone-induced vitellogenin production is partly suppressed by the hepatotoxicity of zearalenone in zebrafish. This study demonstrates that the formation of stable zearalenone-cyclodextrin complexes can strongly decrease or even abolish the zearalenone-induced toxicity, both in vitro and in vivo. Therefore, cyclodextrins appear as promising new mycotoxin binders.


Assuntos
Substâncias Protetoras/farmacologia , Zearalenona/toxicidade , Peixe-Zebra/embriologia , beta-Ciclodextrinas/farmacologia , Animais , Ciclodextrinas/química , Estrogênios/farmacologia , Células HeLa/efeitos dos fármacos , Humanos , Micotoxinas/metabolismo , Substâncias Protetoras/química , Reprodução/efeitos dos fármacos , beta-Ciclodextrinas/química , beta-Ciclodextrinas/metabolismo
7.
BMC Res Notes ; 12(1): 642, 2019 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-31585535

RESUMO

OBJECTIVES: The necrotrophic fungal pathogen Pyrenophora tritici-repentis (Ptr) is the causal agent of tan spot a major disease of wheat. We have generated a new genome resource for an Australian Ptr race 1 isolate V1 to support comparative 'omics analyses. In particular, the V1 PacBio Biosciences long-read sequence assembly was generated to confirm the stability of large-scale genome rearrangements of the Australian race 1 isolate M4 when compared to the North American race 1 isolate Pt-1C-BFP. RESULTS: Over 1.3 million reads were sequenced by PacBio Sequel small-molecule real-time sequencing (SRMT) cell to yield 11.4 Gb for the genome assembly of V1 (285X coverage), with median and maximum read lengths of 8959 bp and 72,292 bp respectively. The V1 genome was assembled into 33 contiguous sequences with a of total length 40.4 Mb and GC content of 50.44%. A total of 14,050 protein coding genes were predicted and annotated for V1. Of these 11,519 genes were orthologous to both Pt-1C-BFP and M4. Whole genome alignment of the Australian long-read assemblies (V1 to M4) confirmed previously identified large-scale genome rearrangements between M4 and Pt-1C-BFP and presented small scale variations, which included a sequence break within a race-specific region for ToxA, a well-known necrotrophic effector gene.


Assuntos
Ascomicetos/genética , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Genoma Fúngico , Interações Hospedeiro-Patógeno/genética , Triticum/microbiologia , Ascomicetos/patogenicidade , Austrália , Mapeamento Cromossômico , Proteínas Fúngicas/classificação , Proteínas Fúngicas/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Micotoxinas/genética , Micotoxinas/metabolismo , Fases de Leitura Aberta , Doenças das Plantas/microbiologia
8.
Biocontrol Sci ; 24(3): 161-166, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31527347

RESUMO

Contamination of agricultural crops by mycotoxins has increased because of the expansion of mycotoxin-producing fungi along with global warming. In this study, the fungal microflora of brown rice grains cultivated in Kyushu region in the southern part of Japan was investigated. A total of 75% of rice samples examined in this study showed less than 30% of fungal contamination rates with a median rate of 12.5%. Some isolates of Aspergillus flavus showed the ability to produce aflatoxins (AFs) (AFB1 production was 62.5-70.4 ng/mL) . Furthermore, AF-producing Aspergillus flavus survived during storage and Aspergillus creber, which produced sterigmatocystin, was detected in a stored rice sample. Although AFs or sterigmatocystin-contamination was not detected in any rice samples, these mycotoxin-producing fungi are distributed and can survive during storage under the natural conditions in Japan. Employing suitable storage conditions is important for preventing mycotoxin contamination of brown rice grains.


Assuntos
Fungos/classificação , Fungos/metabolismo , Microbiota , Micotoxinas/metabolismo , Oryza/microbiologia , Sementes/microbiologia , Armazenamento de Alimentos , Japão
9.
J Basic Microbiol ; 59(11): 1105-1111, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31497881

RESUMO

Six wheat cultivars with varied resistance to Gibberella zeae (Anamorph, Fusarium graminearum Schwabe) were inoculated with six monoconidial strains of G. zeae to investigate the effect of wheat resistance to Fusarium head blight on deoxynivalenol (DON) contents. Samples were selected from grains from each plot, and heavily infected kernels and sound (uninfected) kernels prepared at 10% and 20% Fusarium-diseased kernels (FDK). The proportions of scabbed spikelets (PSS) in the field, total DON (containing DON, 3-acetyl-deoxynivalenol, and 15-acetyl-deoxynivalenol), and F. graminearum DNA (Tri5 DNA) in the samples were quantified in 2006 and 2007. PSS exhibited significant variability among the six wheat cultivars. Potential DON production also had significant differences among the six strains. DON toxin concentrations and F. graminearum DNA (Tri5 DNA) showed no significant differences among the six wheat cultivars following inoculation with similar F. graminearum strains at similar FDK levels and at similar disease severity after culture in similar conditions. DON content in grains of the tested wheat cultivars varied with inoculation strain and FDK level, but not with the resistance level of the cultivars to F. graminearum.


Assuntos
Resistência à Doença , Fusarium/patogenicidade , Micotoxinas/análise , Tricotecenos/análise , Triticum/química , Triticum/microbiologia , DNA Fúngico/análise , Grão Comestível/química , Grão Comestível/microbiologia , Fusarium/genética , Fusarium/metabolismo , Micotoxinas/metabolismo , Doenças das Plantas/microbiologia , Tricotecenos/metabolismo
10.
World J Microbiol Biotechnol ; 35(7): 106, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31267229

RESUMO

Xenorhabdus nematophila HB310 secreted the insecticidal protein toxin complex. Two chitinase genes, chi60 and chi70, were found in X. nematophila toxin complex locus. In order to clarify the function of two chitinases, chi60 and chi70 genes were cloned and expressed in Escherichia coli Transetta (DE3). As a result, we found that the Chi60 and Chi70 belonged to glycoside hydrolases (GH) family 18 with a molecular mass of 65 kDa and 78 kDa, respectively. When colloidal chitin was treated as the substrate, Chi60 and Chi70 were proved to have the highest enzymatic activity at pH 6.0 and 50 °C. Chi60 and Chi70 had obvious growth inhibition effect against the second larvae of Helicoverpa armigera with growth inhibiting rate of 81.99% and 90.51%. Chi70 had synergistic effect with the insecticidal toxicity of Bt Cry 1Ac, but the Chi60 had no synergistic effect with Bt Cry 1Ac. Chi60 and Chi70 showed antifungal activity against Alternaria brassicicola, Verticillium dahliae and Coniothyrium diplodiella. The results increased our understanding of the chitinases produced by X. nematophila and laid a foundation for further studies on the mechanism of the chitinases.


Assuntos
Antifúngicos/farmacologia , Quitinases/antagonistas & inibidores , Quitinases/genética , Quitinases/metabolismo , Xenorhabdus/metabolismo , Alternaria/efeitos dos fármacos , Animais , Ascomicetos/efeitos dos fármacos , Quitina/metabolismo , Quitinases/classificação , Clonagem Molecular , Sinergismo Farmacológico , Ensaios Enzimáticos , Estabilidade Enzimática , Escherichia coli/genética , Expressão Gênica , Glicosídeo Hidrolases/genética , Concentração de Íons de Hidrogênio , Inseticidas/metabolismo , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Peso Molecular , Mariposas/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Micotoxinas/genética , Micotoxinas/metabolismo , Filogenia , Domínios Proteicos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Temperatura Ambiente , Verticillium/efeitos dos fármacos , Xenorhabdus/genética
11.
Int J Food Microbiol ; 306: 108267, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31330453

RESUMO

Fusarium incarnatum-equiseti species complex (FIESC) is commonly detected in Brazilian rice, but knowledge of the species limits and their toxigenic potential is lacking. Seventy strains morphologically identified as FIESC-like, isolated from the major rice-growing regions of Brazil, were subjected to sequencing of EF-1α gene. Among them, 18 strains were selected and analyzed for their RPB2 gene sequences. Nine phylogenetic species were identified, among which eight matched the previously reported FIESC 4 (F. lacertarum), 6, 16, 17 (F. pernambucanum), 20 (F. caatingaense), 24, 26 and 29. One new phylogenetic species was identified, and named FIESC 38. Five strains formed new singleton lineages. The most dominant species were FIESC 26 (22/70 strains) and FIESC 38 (21/70), the newly identified species. The incarnatum morphotype was dominant (10 phylogenetic species) over the equiseti (4 species). Among 46 strains selected to represent all species, only 16 strains produced detectable levels of mycotoxins in vitro. FIESC 26 produced ZEA and FIESC 38 produced both ZEA and DON. ZEA was produced by nine isolates of three other species, among which few isolates produced trichothecenes: DON (5/46), NIV (3/46), 4-ANIV (2/46), 15-ADON (1/46) and 3-ADON (1/46). The T-2 and HT-2 mycotoxins were not detected. Our results contribute novel information on species limits and mycotoxin production within cereal-infecting FIESC in the southern hemisphere and provide baseline data for further exploring morphological differences among the species.


Assuntos
Fusarium/classificação , Fusarium/patogenicidade , Micotoxinas/metabolismo , Oryza/microbiologia , Tricotecenos/metabolismo , Brasil , Grão Comestível/microbiologia , Fusarium/genética , Fusarium/isolamento & purificação , Micotoxinas/genética , Fator 1 de Elongação de Peptídeos/genética , Filogenia , RNA Polimerase II/genética , Tricotecenos/genética
12.
Fungal Biol ; 123(8): 555-557, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31345409

RESUMO

Fungi threaten the security of food supply to human populations on several fronts. They destroy up to 30 % of crop products through disease and spoilage processes, while mycotoxin-producing fungi and opportunistic pathogens endanger food safety. Control of these fungi is vital for improving food security, but current measures are inadequate and further challenges due to human-population growth and climate change are escalating. Investment and innovation in research on strategies to control fungal growth, harnessed through international, inter-disciplinary collaboration across socio-economic boundaries, provides one key to rising to this challenge.


Assuntos
Produtos Agrícolas/microbiologia , Contaminação de Alimentos/análise , Abastecimento de Alimentos , Fungos/metabolismo , Micotoxinas/análise , Doenças das Plantas/microbiologia , Produtos Agrícolas/química , Inocuidade dos Alimentos , Fungos/crescimento & desenvolvimento , Humanos , Micotoxinas/metabolismo
13.
Fungal Biol ; 123(8): 618-624, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31345416

RESUMO

This study examined the effect of climate change (CC) abiotic factors of temperature (20, 25, 30 °C), water activity (aw; 0.995, 0.98) and CO2 exposure (400, 1000 ppm) may have on (a) growth, (b) gene expression of biosynthetic toxin genes (Tri5, Tri6, Tri16), and (c) T-2/HT-2 toxins and associated metabolites by Fusarium langsethiae on oat-based media and in stored oats. Lag phases and growth were optimum at 25 °C with freely available water. This was significantly reduced at 30 °C, at 0.98 aw and 1000 ppm CO2 exposure. In oat-based media and stored oats, Tri5 gene expression was reduced in all conditions except 30 °C, 0.98 aw, elevated CO2 where there was a significant (5.3-fold) increase. The Tri6 and Tri16 genes were upregulated, especially in elevated CO2 conditions. Toxin production was higher at 25 °C than 30 °C. In stored oats, at 0.98 aw, elevated CO2 led to a significant increase (73-fold) increase in T2/HT-2 toxin, especially at 30 °C. Nine T-2 and HT-2 related metabolites were detected, including a new dehydro T-2 toxin (which correlated with T-2 production) and the conjugate, HT-2 toxin, glucuronide. This shows that CC factors may have a significant impact on growth and mycotoxin production by F. langsethiae.


Assuntos
Avena/química , Avena/microbiologia , Proteínas Fúngicas/genética , Fusarium/crescimento & desenvolvimento , Fusarium/genética , Micotoxinas/análise , Mudança Climática , Contaminação de Alimentos/análise , Armazenamento de Alimentos , Proteínas Fúngicas/metabolismo , Fusarium/química , Fusarium/metabolismo , Micotoxinas/metabolismo , Sementes/química , Sementes/microbiologia , Toxina T-2/análogos & derivados , Toxina T-2/análise , Toxina T-2/biossíntese , Toxina T-2/metabolismo
14.
Bioresour Technol ; 291: 121835, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31352166

RESUMO

The correlation between bacteria and fungi in sugarcane tops silage prior to and after aerobic exposure was analyzed. The results showed that the abundance of Lactobacillus increased from 0.03% to 27.84% from d 0-60. Additionally, the abundance of Pichia also increased from 0.003% to 15.46% from d 0-60. Following aerobic exposure, the abundance of Lactobacillus increased by 42.39% at d 3. Moreover, Pichia was the dominant fungal genus after aerobic exposure. Spearman's correlation analysis showed that Pichia was positively correlated with the genera Lactobacillus and Pediococcus, but negatively correlated with the genera Acinetobacter, Citrobacter, and Serratia. Aspergillus, Cladosporium, and Fusarium were positively correlated with the genera Clostridium, Lactobacillus, and Pediococcus, but negatively correlated with the genera Acinetobacter, Citrobacter, and Serratia. Spearman's correlation also suggested that Aspergillus, Cladosporium, and Fusarium could be inhibited by screening Serratia, thereby reducing mycotoxins in silage.


Assuntos
Saccharum/metabolismo , Silagem/microbiologia , Aerobiose , Bactérias , Fermentação , Fungos , Micotoxinas/metabolismo
15.
Int J Food Microbiol ; 306: 108265, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31325815

RESUMO

The use of yeast-derived volatile organic compounds (VOCs) represents a promising strategy for the biological control of various plant pathogens, including mycotoxin-producing fungi. Previous studies demonstrated the efficacy of the low-fermenting yeast Candida intermedia isolate 253 in reducing growth, sporulation, and ochratoxin A biosynthesis by Aspergillus carbonarius MPVA566. This study aimed to investigate whether the inhibitory effect of the yeast volatilome is solely attributable to 2-phenylethanol, its major component, or if a synergistic effect of all volatilome components is required to achieve an effective control of the fungal growth and metabolism. Microbiological methods, HPLC measurements and a UPLC-MS/MS approach were used to investigate the metabolic profile of A. carbonarius MPVA566 at different growing conditions: standard incubation (control), exposed to C. intermedia 253 volatilome, and incubation in the presence of 2-phenylethanol. Both yeast volatilome and 2-phenylethanol succeeded in the macroscopic inhibition of the radial mycelial growth, along with a significant reduction of ochratoxin A production. Functional classification of the fungal proteome identified in the diverse growing conditions revealed a different impact of both yeast VOCs and 2-phenylethanol exposure on the fungal proteome. Yeast VOCs target an array of metabolic routes of fungal system biology, including a marked reduction in protein biosynthesis, proliferative activity, mitochondrial metabolism, and particularly in detoxification of toxic substances. Exposure to 2-phenylethanol only partially mimicked the metabolic effects observed by the whole yeast volatilome, with protein biosynthesis and proliferative activity being reduced when compared with the control samples, but still far from the VOCs-exposed condition. This study represents the first investigation on the effects of yeast-derived volatilome and 2-phenylethanol on the metabolism of a mycotoxigenic fungus by means of proteomics analysis. CHEMICAL COMPOUNDS STUDIED OR USED IN THIS ARTICLE: 2-Phenylethanol (PubChem CID: 6054); ochratoxin-A (PubChem CID: 442530); sodium dodecyl sulfate (PubChem CID: 3423265); dithiothreitol (PubChem CID: 446094); phenylmethylsulfonyl fluoride (PubChem CID: 4784); iodoacetamide (PubChem CID: 3727); ammonium bicarbonate (PubChem CID: 14013); acetic acid (PubChem CID: 176); and acetonitrile (PubChem CID: 6342).


Assuntos
Aspergillus/crescimento & desenvolvimento , Aspergillus/metabolismo , Álcool Feniletílico/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Aspergillus/genética , Candida/metabolismo , Cromatografia Líquida , Fermentação , Micotoxinas/metabolismo , Ocratoxinas/metabolismo , Proteoma , Proteômica , Espectrometria de Massas em Tandem
16.
J Appl Microbiol ; 127(4): 1135-1147, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31271686

RESUMO

AIMS: Emission of toxic metabolites in guttation droplets of common indoor fungi is not well documented. The aims of this study were (i) to compare mycotoxins in biomass and guttation droplets from indoor fungi from a building following health complaints among occupants, (ii) to identify the most toxic strain and to test if mycotoxins in guttation liquids migrated trough air and (iii) to test if toxigenic Penicillium expansum strains grew on gypsum board. METHODS AND RESULTS: Biomass suspensions and guttation droplets from individual fungal colonies representing Aspergillus, Chaetomium, Penicillium, Stachybotrys and Paecilomyces were screened toxic to mammalian cells. The most toxic strain, RcP61 (CBS 145620), was identified as Pen. expansum Link by sequence analysis of the ITS region and a calmodulin gene fragment, and confirmed by the Westerdijk Institute based on ITS and beta-tubulin sequences. The strain was isolated from a cork liner, was able to grow on gypsum board and to produce toxic substances in biomass extracts and guttation droplets inhibiting proliferation of somatic cells (PK-15, MNA, FL) in up to 20 000-fold dilutions. Toxic compounds in biomass extracts and/or guttation droplets were determined by HPLC and LC-MS. Strain RcP61 produced communesins A, B and D, and chaetoglobosins in guttation droplets (the liquid emitted from them) and biomass extracts. The toxins of the guttation droplets migrated c. 1 cm through air and condensed on a cool surface. CONCLUSIONS: The mycotoxin-containing guttation liquids emitted by Pen. expansum grown on laboratory medium exhibited airborne migration and were >100 times more toxic in bioassays than guttation droplets produced by indoor isolates of the genera Aspergillus, Chaetomium, Stachybotrys and Paecilomyces. SIGNIFICANCE AND IMPACT OF THE STUDY: Toxic exudates produced by Pen. expansum containing communesins A, B and D, and chaetoglobosins were transferable by air. This may represent a novel mechanism of mycotoxin dispersal in indoor environment.


Assuntos
Sulfato de Cálcio/química , Materiais de Construção/microbiologia , Compostos Heterocíclicos de 4 ou mais Anéis/metabolismo , Alcaloides Indólicos/metabolismo , Micotoxinas/metabolismo , Penicillium , Penicillium/isolamento & purificação , Penicillium/metabolismo , Penicillium/fisiologia
17.
J Agric Food Chem ; 67(31): 8536-8547, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31310520

RESUMO

Watermelon Fusarium wilt is a common soil-borne disease that has significantly affected its yield. In this study, fusaric acid-deficient mutant designated as ΔFUBT (mutated from Fusarium oxysporum f. sp. niveum, FON) was obtained. The ΔFUBT mutant showed significant decrease in fusaric acid production but maintained wild-type characteristics, such as in vitro colony morphology, size, and conidiation. A field pot experiment demonstrated that ΔFUBT could successfully colonize the rhizosphere and the roots of watermelon, leading to significant reduction in FON colonization in the watermelon plant. In addition, ΔFUBT inoculation significantly improved the rhizosphere microenvironment and effectively increased the resistance in watermelon. This study demonstrated that a nonpathogenic Fusarium mutant (ΔFUBT) could be developed as an effective microbial control agent to alleviate Fusarium wilt disease in watermelon and increase its yield.


Assuntos
Citrullus/microbiologia , Fusarium/genética , Micotoxinas/genética , Doenças das Plantas/microbiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Ácido Fusárico/metabolismo , Fusarium/crescimento & desenvolvimento , Fusarium/fisiologia , Mutação , Micotoxinas/metabolismo , Raízes de Plantas/microbiologia , Rizosfera
18.
J Agric Food Chem ; 67(30): 8411-8418, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31246458

RESUMO

Economic loss of postharvest wheat under poor storage conditions due to fungal spoilage and mycotoxin contamination is severe. In order to study the influencing factors of the aggravation of mildew in natural wheat during storage, we assessed changes in Fusarium mycotoxins by high performance liquid chromatography, changes in fungal communities by high-throughput sequencing, and changes in biochemical components in wheat stored under artificial simulation conditions. Deoxynivalenol was the dominant Fusarium mycotoxin, reaching 1103 µg/kg at 25 °C with 75% relative humidity after 30 weeks. Under these conditions, Fusarium dominated the fungal communities, and Fusarium graminearum was significantly negatively correlated with glutenin (p < 0.05). Low storage temperatures and low humidity result in lower levels of Fusarium mycotoxins. Different fungi tended to consume different wheat components, and the interaction between environmental and biological factors eventually leads to the deterioration of wheat quality. These findings might provide valuable information for control strategies of mildew occurrence during grain storage.


Assuntos
Fungos/isolamento & purificação , Micobioma , Micotoxinas/química , Triticum/microbiologia , Cromatografia Líquida de Alta Pressão , Contaminação de Alimentos/análise , Armazenamento de Alimentos , Fungos/classificação , Fungos/genética , Fusarium/química , Fusarium/classificação , Fusarium/isolamento & purificação , Fusarium/metabolismo , Umidade , Micotoxinas/metabolismo , Sementes/química , Sementes/microbiologia , Tricotecenos/análise , Tricotecenos/metabolismo , Triticum/química
19.
Molecules ; 24(13)2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31247992

RESUMO

Mycotoxins are highly dangerous natural compounds produced by various fungi. Enzymatic transformation seems to be the most promising method for detoxification of mycotoxins. This review summarizes current information on enzymes of different classes to convert various mycotoxins. An in-depth analysis of 11 key enzyme mechanisms towards dozens of major mycotoxins was realized. Additionally, molecular docking of mycotoxins to enzymes' active centers was carried out to clarify some of these catalytic mechanisms. Analyzing protein homologues from various organisms (plants, animals, fungi, and bacteria), the prevalence and availability of natural sources of active biocatalysts with a high practical potential is discussed. The importance of multifunctional enzyme combinations for detoxification of mycotoxins is posed.


Assuntos
Inativação Metabólica , Micotoxinas/química , Micotoxinas/metabolismo , Catálise , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Micotoxinas/classificação , Micotoxinas/genética , Filogenia , Relação Estrutura-Atividade
20.
J Appl Genet ; 60(3-4): 405-416, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31250288

RESUMO

Role of efflux-mediated toxin resistance to trichothecenes is known in trichothecene-producing species. However, the role of trichothecene efflux pump homologues in non-producing fusaria such as F. oxysporum and F. proliferatum was not investigated in detail. Analysis of the homologues of trichothecene efflux pump from multiple fungal species allowed us to uncover and catalogue functional gene copies of conserved structure. Putative Tri12 candidates in Fusarium oxysporum and F. proliferatum were characterised via expression profiling in response to different trigger compounds, providing supporting evidence for role of Tri12 homologues in the resistance to trichothecenes. Our analysis of Tri12 phylogeny also suggests that efflux-mediated trichothecene resistance is likely to predate the divergence of Trichoderma and Fusarium species. On the regulatory level, we posit that the increased tolerance of trichothecenes by F. oxysporum is possibly related to the decoupling of Tri12 homologue expression from pH, due to the deletion of PACC/RIM101 transcription factor binding site in its promoter region.


Assuntos
Proteínas Fúngicas/biossíntese , Fusarium/metabolismo , Micotoxinas/metabolismo , Tricotecenos/metabolismo , Sequência de Aminoácidos/genética , Sítios de Ligação/genética , DNA Fúngico/genética , Proteínas Fúngicas/genética , Fusarium/genética , Regulação Fúngica da Expressão Gênica/genética , Micotoxinas/toxicidade , Filogenia , Fatores de Transcrição/genética , Tricotecenos/toxicidade
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