Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 59
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Food Chem ; 336: 127590, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32763742

RESUMO

This work has been aimed at studying the effect of red thyme oil (RTO, Thymus vulgaris L.) on the shelf-life and Penicillium decay of oranges during cold storage. RTO vapours significantly reduced (P ≤ 0.05) the percentage of infected wounds, the external growth area and the production of spores in inoculated orange fruit stored for 12 days at 7 °C in a polypropylene film selected for its appropriate permeability. Among the RTO compounds, p-cymene and thymol were the most abundant in packed boxes at the end of cold storage. The RTO vapours did not affect the main quality parameters of the oranges, or the taste and odour of the juice. The results have shown that an active packaging, using RTO vapours, could be employed, by the citrus industry, to extend the shelf-life of oranges for fresh market use and juice processing.


Assuntos
Qualidade dos Alimentos , Armazenamento de Alimentos/métodos , Óleos Voláteis/farmacologia , Penicillium/efeitos dos fármacos , Thymus (Planta)/metabolismo , Antioxidantes/química , Citrus/química , Citrus/metabolismo , Citrus/microbiologia , Temperatura Baixa , Sucos de Frutas e Vegetais/análise , Cromatografia Gasosa-Espectrometria de Massas , Concentração de Íons de Hidrogênio , Óleos Voláteis/análise , Penicillium/fisiologia
2.
Int J Food Microbiol ; 334: 108799, 2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-32799117

RESUMO

Aspergillus flavus is a common and ubiquitous fungal species able to colonize several agricultural commodities, in both pre- and post-harvest conditions. This species represents a very harmful plant pathogen for its ability to synthesize aflatoxin B1, responsible for human primary hepatocellular carcinoma and classified as a group I (human carcinogenic) by the International Agency for Research on Cancer. Several approaches have been proposed to control A. flavus development and related aflatoxin production in field and storage conditions. The Succinate Dehydrogenase Inhibitor (SDHI) fungicide boscalid has been shown to control A. flavus growth and aflatoxin contamination both in vitro and in field experiments. However, this compound is classified as medium-high risk fungicide for triggering fungal resistance and, indeed, resistant strains can occur on crops treated with boscalid. In this paper, we selected laboratory A. flavus strains resistant to boscalid grown on agar medium containing 50 mg/L of boscalid. In order to investigate the molecular mechanism responsible for the resistant phenotype, specific primer pairs were designed to amplify the whole SdhB, SdhC and SdhD genes. By amino acid sequence analysis, two point mutations, Tyrosine replacing Histidine at codon 249 of SdhB (H249Y) and Arginine replacing Glycine at codon 91 of SdhC (G91R), were identified. The effect of SDHI boscalid and isopyrazam on mycelial growth and conidial germination was evaluated. Both resistant genotypes showed high resistance (MIC and EC50 > 1000 mg/L) to boscalid. A positive cross-resistance was found between boscalid and isopyrazam. Specific sub-lethal doses of both fungicides (0.5 mg/L of boscalid and 0.01 mg/L of isopyrazam) interfered with the mechanisms associated to pigmentation of colonies. In particular, fungal colonies appeared depigmented lacking the typical A. flavus green colour shown on un-amended fungicide medium. A strict correlation between lack of pigmentation and increasing aflatoxin production was also observed.


Assuntos
Aflatoxinas/biossíntese , Aspergillus flavus/genética , Farmacorresistência Fúngica/genética , Fungicidas Industriais/farmacologia , Succinato Desidrogenase/antagonistas & inibidores , Aspergillus flavus/efeitos dos fármacos , Aspergillus flavus/crescimento & desenvolvimento , Aspergillus flavus/metabolismo , Compostos de Bifenilo/farmacologia , Farmacorresistência Fúngica/efeitos dos fármacos , Mutação , Niacinamida/análogos & derivados , Niacinamida/farmacologia , Norbornanos/farmacologia , Pigmentação/efeitos dos fármacos , Polimorfismo Genético , Pirazóis/farmacologia , Succinato Desidrogenase/genética
3.
Plant Dis ; 102(2): 282-291, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30673533

RESUMO

Species of Aspergillus section Nigri are commonly associated with maize kernels, and some strains can produce fumonisin mycotoxins. However, there is little information about the extent to which these fungi contribute to fumonisin contamination in grain, the damage they cause to maize ears, or their effects on maize seed germination and seedling health. We compared fumonisin-producing and nonproducing strains of A. niger, A. welwitschiae, A. phoenicis, A. tubingensis, and A. carbonarius from the United States and Italy in laboratory and field studies to assess their ability to contribute to fumonisin contamination, to cause maize ear rot, and to affect seed germination and seedling growth. In laboratory experiments, some strains of each Aspergillus species reduced germination or seedling growth, but there was high variability among strains within species. There were no consistent differences between fumonisin-producing and nonproducing strains. In field studies in Iowa and Illinois, strains were variable in their ability to cause ear rot symptoms, but this was independent of the ability of the Aspergillus strains to produce fumonisins. Contamination of grain with fumonisins was not consistently increased by inoculation with Aspergillus strains compared with the control, and was much greater in F. verticillioides-inoculated treatments than in Aspergillus-inoculated treatments. However, the ratio of the FB analogs FB2 and FB1 was altered by inoculation with some Aspergillus strains, indicating that FB2 production by Aspergillus strains occurred in the field. These results demonstrate the pathogenic capabilities of strains of Aspergillus in section Nigri, but suggest that their effects on maize ears and seedlings are not related to their ability to produce fumonisins, and that fumonisin contamination of grain caused by Aspergillus spp. is not as significant as that caused by Fusarium spp.


Assuntos
Aspergillus/patogenicidade , Fumonisinas/metabolismo , Doenças das Plantas/microbiologia , Zea mays/microbiologia , Idaho , Illinois , Iowa , Itália , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Virulência , Zea mays/crescimento & desenvolvimento
4.
Int J Food Microbiol ; 238: 56-62, 2016 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-27591387

RESUMO

Filamentous fungi are the main pathogens of withered grapes destined for passito wine production. Knowledge of which species inhabit these post-harvest fruits and their pathogenicity is essential in order to develop strategies to control infection, but is still scarce. This study investigated the predominant mycobiota of withered grapes through a cultivation-dependent approach. Strain and species heterogeneity was evidenced on examining isolates collected over three consecutive years. Colony morphology and PCR-restriction fragment length polymorphism (PCR-RFLP) analysis revealed the occurrence of several phenotypes and haplotypes, respectively. Strains were phylogenetically analyzed based on sequence typing of different genes or regions (e.g. calmodulin, ß-tubulin and internal transcribed spacer region). Beside the most common necrotrophic-saprophytic species of Penicillium, Aspergillus, Alternaria and Botrytis species responsible for fruit rot, other saprobic species were identified (e.g. Trichoderma atroviride, Sarocladium terricola, Arthrinium arundinis and Diaporthe eres) generally not associated with post-harvest fruit diseases. Species such as Penicillium ubiquetum, Cladosporium pseudocladosporioides, Lichtheimia ramosa, Sarocladium terricola, Diaporthe nobilis, Bipolaris secalis, Paraconiothyrium fuckelii and Galactomyces reessii that had never previously been isolated from grapevine or grape were also identified. Moreover, it was not possible to assign a species to some isolates, while some members of Didymosphaeriaceae and Didymellaceae remained unclassified even at genus level. This study provides insights into the diversity of the epiphytic fungi inhabiting withered grapes and evidences the importance of their identification to understand the causes of fruit diseases. Finally, phylogenetic species delimitation furnished data of interest to fungal taxonomy.


Assuntos
Biodiversidade , Frutas/microbiologia , Fungos/classificação , Fungos/genética , Filogenia , Polimorfismo de Fragmento de Restrição , Vitis/microbiologia , Alternaria/classificação , Alternaria/genética , Alternaria/isolamento & purificação , Ascomicetos/classificação , Ascomicetos/genética , Ascomicetos/isolamento & purificação , Aspergillus/classificação , Aspergillus/genética , Aspergillus/isolamento & purificação , Botrytis/classificação , Botrytis/genética , Botrytis/isolamento & purificação , Microbiologia de Alimentos , Fungos/isolamento & purificação , Penicillium/classificação , Penicillium/genética , Penicillium/isolamento & purificação , Reação em Cadeia da Polimerase , Vinho/microbiologia
5.
Artigo em Inglês | MEDLINE | ID: mdl-24313896

RESUMO

Fumonisins (FBs), which are carcinogenic mycotoxins, are known to be typically produced by several phytopathogenic fungal species belonging to the genus Fusarium. F. proliferatum and F. verticillioides, two important pathogens of maize worldwide, are the most common species that produce FBs. The main FBs produced by these species are FB1, FB2 and FB3. Moreover, recently, fungal strains belonging to Aspergillus niger have been also reported to produce FBs (in particular, FB2 and FB4). In a survey on maize carried out in Central Italy, 17 maize kernel samples were collected at harvest and analysed for FB1, FB2 and FB3, as well as fungal contamination, with a particular attention to the species-producing FBs. All 17 samples were contaminated by F. verticillioides and/or F. proliferatum at a level ranging from 13% to 100% of kernels. However, 10 out of 17 samples were also contaminated by Aspergillus section Nigri with a range from 6% to 68% of kernels. There was a significant inverse logarithmic relationship between levels of Fusarium and Aspergillus contamination. All samples were contaminated by FBs; FB1 ranged from 0.09 to 30.2 µg g(-1), whereas FB2 ranged from 0.04 to 13.2 µg g(-1). The ratio of FB2/FB1 contamination in the maize samples was evaluated and the highest values occurred in samples contaminated with Aspergillus section Nigri. Thirty strains of Aspergillus section Nigri isolated from these samples were molecularly identified (based on sequences of two housekeeping genes) and analysed for their capability to produce FB2. Among the 30 strains isolated, 12 were identified as Aspergillus welwitschiae (syn. A. awamori) and 18 as A. tubingensis. FB2 was produced by five out of 12 strains of A. welwitschiae within a range of 0.20-5 µg g(-1). This is the first report showing the capability of Aspergillus section Nigri from maize to produce FB2 and its possibility to contribute to FB accumulation in kernels.


Assuntos
Aspergillus/metabolismo , Aspergillus/patogenicidade , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Fumonisinas/toxicidade , Zea mays/microbiologia , Zea mays/toxicidade , Ração Animal/análise , Ração Animal/microbiologia , Ração Animal/toxicidade , Animais , Aspergillus/classificação , Contaminação de Alimentos/prevenção & controle , Fumonisinas/metabolismo , Fusarium/metabolismo , Fusarium/patogenicidade , Humanos , Zea mays/química
6.
J Appl Microbiol ; 116(2): 390-9, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24138702

RESUMO

AIMS: The aim of this study was to analyse the transcriptional regulation of enniatins (ENs) production in Fusarium avenaceum. METHODS AND RESULTS: We develop a new method to quantify ENs in FDM agar medium. We performed an LC/MS/MS analysis to evaluate enniatin A, A1, B, B1 and B4 production by seven F. avenaceum strains and, in a time-course experiment, by ITEM 3404 to analyse the transcriptional regulation of the esyn1 gene. The expression profile, achieved by Real time reverse transcriptase assay, showed an activation of gene transcription at the seventh day of incubation, corresponding to the higher increase of total ENs production. Enniatin B was the most abundant ENs analogues, representing the 90% of total ENs. The relative percentage of ENs remained unaltered during the experiment. CONCLUSIONS: We reported a transcriptional regulation of esyn1 responsible for the modulation of ENs biosynthesis. SIGNIFICANCE AND IMPACT OF THE STUDY: Enniatins are cyclic depsipeptides metabolites with a wide range of biological activities. They are also widespread contaminants in grains and cereals due to infection by enniatin-producing Fusarium species. This is the first article describing the transcriptional regulation of esyn1 gene that modulates ENs production in Fusarium avenaceum and provides new knowledge about the molecular mechanism underlying the biosynthesis of these important fungal metabolites in this toxigenic fungal species.


Assuntos
Depsipeptídeos/biossíntese , Fusarium/metabolismo , Meios de Cultura/química , Depsipeptídeos/química , Depsipeptídeos/genética , Fusarium/genética , Fusarium/crescimento & desenvolvimento , Cromatografia Gasosa-Espectrometria de Massas , Reação em Cadeia da Polimerase em Tempo Real , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem , Transcrição Gênica
7.
Int J Food Microbiol ; 167(1): 57-66, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-23859402

RESUMO

Fungal biodiversity is one of the most important contributors to the occurrence and severity of mycotoxin contamination of crop plants. Phenotypic and metabolic plasticity has enabled mycotoxigenic fungi to colonize a broad range of agriculturally important crops and to adapt to a range of environmental conditions. New mycotoxin-commodity combinations provide evidence for the ability of fungi to adapt to changing conditions and the emergence of genotypes that confer enhanced aggressiveness toward plants and/or altered mycotoxin production profiles. Perhaps the most important contributor to qualitative differences in mycotoxin production among fungi is variation in mycotoxin biosynthetic genes. Molecular genetic and biochemical analyses of toxigenic fungi have elucidated specific differences in biosynthetic genes that are responsible for intra- and inter-specific differences in mycotoxin production. For Aspergillus and Fusarium, the mycotoxigenic genera of greatest concern, variation in biosynthetic genes responsible for production of individual families of mycotoxins appears to be the result of evolutionary adaptation. Examples of such variation have been reported for: a) aflatoxin biosynthetic genes in Aspergillus flavus and Aspergillus parasiticus; b) trichothecene biosynthetic genes within and among Fusarium species; and c) fumonisin biosynthetic genes in Aspergillus and Fusarium species. Understanding the variation in these biosynthetic genes and the basis for variation in mycotoxin production is important for accurate assessment of the risks that fungi pose to food safety and for prevention of mycotoxin contamination of crops in the field and in storage.


Assuntos
Biodiversidade , Inocuidade dos Alimentos , Fungos/fisiologia , Micotoxinas/biossíntese , Produtos Agrícolas/microbiologia , Contaminação de Alimentos/prevenção & controle , Fungos/classificação , Fungos/genética , Micotoxinas/química , Micotoxinas/genética , Micotoxinas/metabolismo , Medição de Risco
8.
Int J Food Microbiol ; 149(2): 171-6, 2011 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-21723640

RESUMO

Aspergillus section Nigri populations isolated from seven growing regions from Argentina were characterized by sequencing in order to identify species responsible for production of ochratoxin A (OTA) and fumonisins (FB(s)). Sequences of genes encoding calmodulin, ß-tubulin, the second largest subunit of RNA polymerase II and translation elongation factor 1 alpha were analysed. The phylogenetic analysis showed the presence of six lineages: A. carbonarius, A. tubingensis, A. niger, A. japonicus, A. homomorphus and A. foetidus grouped in four major clusters. The molecular tools used allowed the identification for the first time of A. homomorphus from vineyards. OTA production confirmed the importance of A. carbonarius as the main ochratoxigenic species isolated and, to a variable degree, of A. niger and A. tubingensis, which were by far the most commonly occurring species on grapes in Argentina. The only strains able to produce OTA and fumonisins (B(2)-B(4)) belong to the A. niger cluster.


Assuntos
Aspergillus/metabolismo , Fumonisinas/metabolismo , Ocratoxinas/metabolismo , Argentina , Aspergillus/classificação , Aspergillus/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Fumonisinas/química , Ocratoxinas/química , Filogenia , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismo , Vitis/microbiologia
9.
Artigo em Inglês | MEDLINE | ID: mdl-20432101

RESUMO

The potential risk of exposure to fumonisin B(2) (FB(2)) in the grape-wine chain has recently been revealed after a report of Aspergillus niger in grapes and its ability to produce FB(2) and FB(4). The occurrence of these two fumonisins in wine was investigated by LC/MS/MS in 51 market samples (45 red, five white and one rose wine) produced in various Italian regions. Nine samples of red wine were found to be contaminated by fumonisin B(2) at levels ranging from 0.4 to 2.4 ng/ml, while FB(4) was not detected in any of the tested samples. This is the first report on the natural occurrence of FB(2) in wine, indicating that, although at low levels, there is a potential risk of FB(2) exposure for the wine-consumer.


Assuntos
Contaminação de Alimentos , Fumonisinas/análise , Vinho/análise , Cromatografia Líquida de Alta Pressão , Fumonisinas/química , Fumonisinas/isolamento & purificação , Itália , Limite de Detecção , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem , Vinho/efeitos adversos
10.
Artigo em Inglês | MEDLINE | ID: mdl-20352549

RESUMO

In a survey carried out on 87 rotted fig fruits samples collected in the Apulia region of Italy, the authors isolated 126 Fusarium strains identified as F. ramigenum (69 strains), F. solani (49), F. proliferatum (five) and three not identified. Investigation on the fertility of the strains belonging to F. proliferatum and F. ramigenum revealed that only strains of F. proliferatum were fertile. The identity of F. ramigenum strains was confirmed by sequencing a portion of the translation elongation factor-1alpha gene. When Fusarium species were analysed for their toxigenicity, 37/69 strains of F. ramigenum produced fusaric acid (FA) up to 525 mg kg(-1); 30 strains produced beauvericin (BEA) up to 190 mg kg(-1); 60 strains produced fumonisin B(1) (FB(1)) and fumonisin B(2) (FB(2)) up to 1575 mg kg(-1) of total FBs; and two strains produced fusaproliferin (FUP) up to 345 mg kg(-1); all five strains of F. proliferatum produced FA at low levels; two strains produced BEA up to 205 mg kg(-1); one strain produced FB(1) and FB(2), 1100 and 470 mg kg(-1), respectively; and one strain produced FUP, 820 mg kg(-1); F. solani (30 strains) produced FA, 13 strains up to 215 mg kg(-1). Few fungal extracts showed high toxicity toward brine shrimp larvae and in some cases in relation to BEA and FA content. A pathogenic assay on fig fruits showed that all three species were pathogenic, with higher virulence of F. ramigenum. These data report for the first time the production of BEA and FB(1)/FB(2) by F. ramigenum and show that it is a main agent of fig endosepsis in Apulia and can contribute to fumonisin contamination of fresh and dried figs.


Assuntos
Ficus/microbiologia , Frutas/microbiologia , Fusarium/isolamento & purificação , Fusarium/patogenicidade , Micotoxinas/biossíntese , Doenças das Plantas/microbiologia , Animais , Artemia/efeitos dos fármacos , Bioensaio , Extratos Celulares/química , Extratos Celulares/toxicidade , Depsipeptídeos/metabolismo , Fertilidade/genética , Contaminação de Alimentos , Frutas/crescimento & desenvolvimento , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Ácido Fusárico/biossíntese , Ácido Fusárico/química , Ácido Fusárico/isolamento & purificação , Fusarium/genética , Fusarium/metabolismo , Genes Fúngicos Tipo Acasalamento , Itália , Técnicas de Tipagem Micológica , Fator 1 de Elongação de Peptídeos/química , Fator 1 de Elongação de Peptídeos/genética , Filogenia , Especificidade da Espécie , Terpenos/metabolismo , Virulência
11.
Artigo em Inglês | MEDLINE | ID: mdl-20204912

RESUMO

The importance and widespread incidence of Fusarium poae as a natural contaminant of wheat in different climatic areas warrants investigation into the genetic diversity and toxin profile of a northern Italy population. Eighty-one strains of F. poae isolated from durum wheat kernels, identified by species-specific polymerase chain reaction and translation elongation factor-1alpha gene sequence analysis, were genetically characterized by the amplified fragment length polymorphism (AFLP) technique and analysed by high-pressure liquid chromatography for their ability to produce the beauvericin (BEA) and trichothecene mycotoxins. A high level of variability was observed by using AFLP analyses, with the lowest level of genetic similarity among the strains being approximately 61%. Most of the strains, 95%, produced BEA at <2655 microg g(-1); 88% produced the trichothecene nivalenol at <865 microg g(-1) and 76% produced the trichothecene fusarenon-X at <167 microg g(-1). These data show that F. poae can produce high amounts of BEA together with trichothecenes, and can represent a high potential mycotoxin risk in Italy for wheat colonized by this species.


Assuntos
Depsipeptídeos/biossíntese , Fusarium/genética , Fusarium/metabolismo , Variação Genética , Micotoxinas/biossíntese , Tricotecenos/biossíntese , Triticum/microbiologia , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Cromatografia Líquida de Alta Pressão , Depsipeptídeos/química , Grão Comestível/microbiologia , Contaminação de Alimentos , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Fusarium/classificação , Fusarium/isolamento & purificação , Genes Fúngicos , Itália , Limite de Detecção , Técnicas de Tipagem Micológica , Micotoxinas/química , Fator 1 de Elongação de Peptídeos/química , Fator 1 de Elongação de Peptídeos/genética , Filogenia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Reação em Cadeia da Polimerase , Especificidade da Espécie , Espectrometria de Massas em Tandem , Fatores de Elongação da Transcrição/química , Fatores de Elongação da Transcrição/genética , Tricotecenos/química
12.
Artigo em Inglês | MEDLINE | ID: mdl-19742356

RESUMO

Aspergillus niger has been recently found to produce fumonisin B(2) (FB(2)). Thirty-one strains belonging to four Aspergillus species isolated from grape were evaluated for FB(2) production on agar plates. Four out of eight strains of A. niger produced FB(2) (29-293 microg g(-1)). None of the strains of A. uvarum (n = 7), A. tubingensis (8) and A. carbonarius (8) produced detectable amounts of toxin. The capability to produce FB(2) was also confirmed by some A. niger strains artificially inoculated on grape berries. Natural occurrence of FB(2), at levels of 0.01 and 0.4 microg ml(-1), was found in two samples of must collected in Apulian cellars in 2007. This is the first report of FB(2) contamination in must. These findings suggest that there is a potential risk of exposure to FB(2) in the grape-wine chain for consumers and that A. niger may represent the major fumonisin-producing species among black Aspergilli occurring on grapes.


Assuntos
Aspergillus niger/metabolismo , Contaminação de Alimentos/análise , Fumonisinas/metabolismo , Vitis/microbiologia , Aspergillus/classificação , Aspergillus/metabolismo , Aspergillus niger/isolamento & purificação , Análise de Alimentos/métodos , Microbiologia de Alimentos
13.
Artigo em Inglês | MEDLINE | ID: mdl-19680913

RESUMO

Fusarium subglutinans (teleomorph Gibberella subglutinans, member of the Gibberella fujikuroi complex) is an important toxigenic pathogen of maize. Recently, two cryptic species (Groups 1 and 2) have been described within F. subglutinans, but little is known about the occurrence of the two groups in North America or their relative capacities to produce mycotoxins. In this study, 58 F. subglutinans strains from kernels of maize grown in Iowa, USA, were evaluated for cryptic speciation and production of the mycotoxins fusaproliferin and beauvericin. Fifty-six of the 58 strains (97%) belonged to Group 2, and two strains belonged to Group 1, based on restricted fragment length polymorphisms derived from amplification of histone H3 and beta-tubulin gene fragments. Fifty-four Group 2 strains and both Group 1 strains produced fusaproliferin at concentrations ranging from 12 to 3000 microg g(-1) of solid maize culture. None of the F. subglutinans strains from Iowa produced beauvericin at detectable amounts, although most F. subglutinans strains from Europe and elsewhere are beauvericin producers. These results indicate that F. subglutinans strains infecting maize kernels in Iowa belong almost exclusively to Group 2 and that they have a high potential for fusaproliferin production; furthermore, the results confirm an association between Group 2 genotypes and lack of beauvericin production. This is the first report characterizing the phylogenetic groups of F. subglutinans occurring in Iowa; the predominance of Group 2 suggests that populations of the fungus in Iowa and Europe remain isolated from each other. Fusaproliferin contamination of grain appears to be a risk wherever F. subglutinans occurs, but beauvericin contamination from F. subglutinans is associated only with Group 1.


Assuntos
Fusarium , Micotoxinas/análise , Terpenos/análise , Zea mays/química , Animais , Contaminação de Alimentos , Fusarium/classificação , Fusarium/genética , Fusarium/metabolismo , Gibberella/classificação , Gibberella/genética , Gibberella/metabolismo , Humanos , Iowa , Micotoxinas/genética , Zea mays/microbiologia
14.
J Food Prot ; 72(4): 894-7, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19435246

RESUMO

The grape berry moth Lobesia botrana is a key pest in vineyards in southern Europe. Damage caused by L. botrana larvae may encourage growth of black aspergilli, leading to ochratoxin A (OTA) accumulation in grapes. Field trials were conducted during three grape growing seasons (2005 through 2007) in Apulia, Italy, to evaluate an insecticide control strategy for L. botrana in the vineyard as an indirect method of reducing OTA contamination by reducing black aspergilli on the grapes. In the 2005 field trials, the insecticide treatment controlled attacks by L. botrana larvae and reduced OTA concentrations by up to 66% in the must samples of Negroamaro and Primitivo grape varieties. Significant differences (P < or = 0.05) also were observed in the incidence of black aspergilli. Environmental conditions in 2006 and 2007 resulted in a natural low level of infestation by L. botrana, low levels of OTA in both treated and untreated samples, and no significant differences between treated and nontreated samples. The results of our field study confirm previous reports that L. botrana is an important risk factor for OTA accumulation and are consistent with the hypothesis that controlling L. botrana in vineyards reduces OTA concentrations in grapes.


Assuntos
Contaminação de Alimentos/prevenção & controle , Controle de Insetos , Ocratoxinas/análise , Doenças das Plantas/microbiologia , Vitis , Animais , Aspergillus , Clorpirifos/farmacologia , Hidrazinas/farmacologia , Inseticidas/farmacologia , Hormônios Juvenis/farmacologia , Larva , Mariposas , Chuva , Fatores de Tempo , Vitis/química , Vitis/microbiologia , Vitis/parasitologia
15.
Int J Food Microbiol ; 127(3): 312-5, 2008 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-18804303

RESUMO

Fusarium subglutinans is a maize ear rot pathogen and producer of beauvericin and other mycotoxins. This species has recently been split into two major phylogenetic within-species groups based on RFLP DNA sequence polymorphisms identified in the histone H3 and beta-tubulin sequences. A Pan European collection of the fungus originating mostly from maize was subjected to phylogenetic analysis by RFLP grouping and to chemical analysis for beauvericin production. Of the 62 isolates belonging to Group 1, 48 (77%) produced from 10 to 532 microg/g of beauvericin, whereas none of the 39 Group 2 isolates synthesized detectable amounts of the mycotoxin. The association between RFLP group and beauvericin production is consistent with the existence of two reproductively isolated subgroups within F. subglutinans and indicates that the toxicological risk of isolates of F. subglutinans depends on the group with which they are affiliated.


Assuntos
Depsipeptídeos/biossíntese , Fusarium/classificação , Fusarium/metabolismo , Filogenia , Zea mays/microbiologia , DNA Fúngico/genética , Depsipeptídeos/análise , Contaminação de Alimentos/análise , Micotoxinas/análise , Micotoxinas/biossíntese , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Especificidade da Espécie , Zea mays/química
16.
Int J Food Microbiol ; 127(3): 241-5, 2008 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-18707788

RESUMO

The Amplified Fragment Length Polymorphism (AFLP) technique was applied for the first time to investigate the genotyping of Oenococcus oeni, the most important species involved in malolactic fermentation (MLF) in wine. A total of 87 out of 220 lactic acid bacteria, isolates from "Primitivo" wine (Apulia, Italy) undergoing MLF, identified as O. oeni by species-specific PCR and 16S rRNA sequence analysis, were studied by AFLP analysis. Four main clusters were distinguished and three of them showed intraspecific homology higher than 60%. A total of 28 strains, representative of AFLP clusters, were tested for malate metabolism in order to gain information on their malolactic performances. Significant differences were observed among strains for malic acid consumed, biomass produced and specific malic acid consumption rate. These findings indicated that AFLP technique is reliable for typing O. oeni strains and that, together with metabolism studies it may be used to individuate possible candidates as industrial malolactic starters.


Assuntos
Leuconostoc , Malatos/metabolismo , Polimorfismo de Fragmento de Restrição , RNA Ribossômico 16S/genética , Vinho/microbiologia , Análise por Conglomerados , DNA Bacteriano/genética , Fermentação , Microbiologia de Alimentos , Amplificação de Genes , Genótipo , Leuconostoc/classificação , Leuconostoc/genética , Leuconostoc/crescimento & desenvolvimento , Leuconostoc/metabolismo , Filogenia , Reação em Cadeia da Polimerase/métodos , Análise de Sequência de DNA , Especificidade da Espécie
17.
Int J Food Microbiol ; 119(1-2): 11-6, 2007 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-17765992

RESUMO

Fusarium ear rot of maize and Aspergillus rot of grape are two examples of important plant diseases caused by complexes of species of mycotoxigenic fungi. These complexes of species tend to be closely related, produce different classes of mycotoxins, and can induce disease under different environmental conditions. The infection of maize and grape with multiple fungal species and the resulting production of large classes of mycotoxins is an example of mutual aggressiveness of microorganisms toward host species as well as to humans and animals that eat feed or food derived from the infected and contaminated plants. Infection of crop plant with a complex of microbial species certainly represents a greater threat to a crop plant and to human and animal health than infection of the plant with a single fungal species.


Assuntos
Aspergillus/classificação , Biodiversidade , Fusarium/classificação , Micotoxinas/toxicidade , Doenças das Plantas/microbiologia , Aspergillus/genética , Aspergillus/metabolismo , Microbiologia de Alimentos , Fusarium/genética , Fusarium/metabolismo , Filogenia , Especificidade da Espécie , Vitis/química , Vitis/microbiologia , Zea mays/química , Zea mays/microbiologia
18.
Food Addit Contam ; 24(10): 1138-47, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17886186

RESUMO

Black aspergilli, and particularly Aspergillus carbonarius, are responsible for ochratoxin A production in grapes. Correct identification of these species is essential for toxicological risk assessment in grape and wine. A low-complexity oligonucleotide microarray (OLISA, Apibio, F) based on DNA oligonucleotides probes, obtained from sequences of the calmodulin gene, was set up in order to detect A. carbonarius, A. japonicus/A. aculeatus and A. ibericus isolated from grape. The designed microarray distinguished all Aspergillus species and the detection limit for A. carbonarius was 3.2 pg of DNA as a template for the PCR reaction. This microarray offers a quick and parallel analysis to detect individual Aspergillus species in pure cultures and in naturally contaminated grape samples.


Assuntos
Aspergillus/isolamento & purificação , Ocratoxinas/biossíntese , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Vitis/microbiologia , Aspergillus/classificação , Aspergillus/genética , DNA Fúngico/genética , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Expressão Gênica , Reação em Cadeia da Polimerase/métodos , Especificidade da Espécie
19.
Int J Food Microbiol ; 118(2): 158-63, 2007 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-17706820

RESUMO

The knowledge of toxigenic profiles of fungal plant pathogens is of extreme importance for evaluating the potential toxicity of infected plant products. Ninety-six fungal isolates belonging to 28 species in the Gibberella fujikuroi complex were studied for the production of beauvericin, enniatins and fusaproliferin in rice cultures. Toxin production ranged from 5 to 3000 microg/g for beauvericin, 2 to 131 microg/g for enniatins, and 4 to 440 microg/g for fusaproliferin. Beauvericin was the most common metabolite produced by 16 species followed by fusaproliferin with 11 species and enniatins with 4 species. The production of beauvericin by F. bulbicola, F. denticulatum, F. lactis, F. phyllophilum, F. pseudocircinatum, and F. succisae and fusaproliferin by F. antophilum, F. begoniae, F. bulbicola, F. circinatum, F. concentricum, F. succisae, and F. udum is reported here for the first time. Brine shrimp larvae were most sensitive to culture extracts of F. acutatum (up to 94+/-3%), F. concentricum (up to 99+/-1%), F. denticuatum (up to 100%) and F. sacchari (up to 100%). Toxicity towards brine shrimp was significantly correlated with the beauvericin content of the fungal extracts with few exceptions. These data indicate that beauvericin and fusaproliferin are common metabolites of species of the G. fujikuroi complex and pose a risk for a possible toxin accumulation in their respective host plant products. However, data from the brine shrimp bioassay showed that further toxic metabolites within this complex need to be characterized.


Assuntos
Artemia/efeitos dos fármacos , Microbiologia de Alimentos , Gibberella/metabolismo , Gibberella/patogenicidade , Micotoxinas/farmacologia , Animais , Artemia/crescimento & desenvolvimento , Artemia/microbiologia , Bioensaio , Depsipeptídeos/biossíntese , Depsipeptídeos/farmacologia , Relação Dose-Resposta a Droga , Fusarium/metabolismo , Fusarium/patogenicidade , Micotoxinas/biossíntese , Oryza/microbiologia , Especificidade da Espécie
20.
Int J Food Microbiol ; 111 Suppl 1: S28-34, 2006 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-16697479

RESUMO

Aspergillus carbonarius is the main species responsible for the production of ochratoxin A (OTA) in wine grapes. To monitor and quantify A. carbonarious in grapes, a quantitative real-time PCR assay was developed as a possible tool for predicting the potential ochratoxigenic risk. DNA extraction from grape berries was performed by using conventional extraction and clean up through EZNA Hi-bond spin columns. A TaqMan probe was used to quantify A. carbonarius genomic DNA in grape berries samples. An exogenous internal positive control was used to overcome DNA recovery losses due to matrix inhibition. The quantification of fungal genomic DNA in naturally contaminated grape was performed using the TaqMan signal versus spectrophotometrically measured DNA quantities (Log10) calibration curve with a linearity range from 50 to 5 x 10(-4) ng of DNA. A positive correlation (R2=0.92) was found between A. carbonarious DNA content and OTA concentration in naturally contaminated grape samples. This is the first application of TaqMan real-time PCR for identifying and quantifying A. carbonarius genomic DNA occurring in grapes. The rapid DNA extraction method for grapes, together with the commercial availability of reagents and instrumentation, allows to perform a remarkable number of reproducible assays (96-well format) in less than 4 h.


Assuntos
Aspergillus/isolamento & purificação , DNA Fúngico/química , Reação em Cadeia da Polimerase/métodos , Vitis/microbiologia , Aspergillus/metabolismo , Qualidade de Produtos para o Consumidor , DNA Fúngico/genética , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Humanos , Ocratoxinas/análise , Ocratoxinas/biossíntese , Especificidade da Espécie , Vitis/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...