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1.
JMIR Res Protoc ; 12: e50682, 2023 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-38060296

RESUMO

BACKGROUND: The COVID-19 pandemic has had a profound impact on emergency department (ED) care in Canada and around the world. To prevent transmission of COVID-19, personal protective equipment (PPE) was required for all ED care providers in contact with suspected cases. With mass vaccination and improvements in several infection prevention components, our hypothesis is that the risks of transmission of COVID-19 will be significantly reduced and that current PPE use will have economic and ecological consequences that exceed its anticipated benefits. Evidence is needed to evaluate PPE use so that recommendations can ensure the clinical, economic, and environmental efficiency (ie, eco-efficiency) of its use. OBJECTIVE: To support the development of recommendations for the eco-efficient use of PPE, our research objectives are to (1) estimate the clinical effectiveness (reduced transmission, hospitalizations, mortality, and work absenteeism) of PPE against COVID-19 for health care workers; (2) estimate the financial cost of using PPE in the ED for the management of suspected or confirmed COVID-19 patients; and (3) estimate the ecological footprint of PPE use against COVID-19 in the ED. METHODS: We will conduct a mixed method study to evaluate the eco-efficiency of PPE use in the 5 EDs of the CHU de Québec-Université Laval (Québec, Canada). To achieve our goals, the project will include four phases: systematic review of the literature to assess the clinical effectiveness of PPE (objective 1; phase 1); cost estimation of PPE use in the ED using a time-driven activity-based costing method (objective 2; phase 2); ecological footprint estimation of PPE use using a life cycle assessment approach (objective 3; phase 3); and cost-consequence analysis and focus groups (integration of objectives 1 to 3; phase 4). RESULTS: The first 3 phases have started. The results of these phases will be available in 2023. Phase 4 will begin in 2023 and results will be available in 2024. CONCLUSIONS: While the benefits of PPE use are likely to diminish as health care workers' immunity increases, it is important to assess its economic and ecological impacts to develop recommendations to guide its eco-efficient use. TRIAL REGISTRATION: PROSPERO CRD42022302598; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=302598. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/50682.

2.
Med Mycol ; 53(4): 405-8, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25541560

RESUMO

Bacteraemia was reported to be associated with false-positive 1→3-ß-D-glucan (BG) assay results. We thus prospectively assessed the reactivity of the BG (Fungitell) in samples of 21 adults with bacteraemia: . BG was negative in all and is s therefore an unlikely cause of false positive BG in adults.


Assuntos
Bacteriemia/patologia , beta-Glucanas/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Proteoglicanas , Soro/química , Adulto Jovem
3.
Clin Kidney J ; 6(3): 300-4, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26064489

RESUMO

A 67-year-old man was evaluated for haematuria, with a rising creatinine level from 88 to 906 µmol/L and positive c-anti-neutrophil cytoplasm antibody (ANCA)/anti-proteinase 3 (anti-PR3). A kidney biopsy revealed necrotizing glomerulonephritis with a 'full-house' pattern on immunofluorescence microscopy. Echocardiography and blood cultures growing Gemella sanguinis diagnosed endocarditis. Dialysis was required for a month. Three months later, following valve replacement, glucocorticoids and 2 months of antibiotic therapy, the creatinine level decreased to 62 µmol/L and c-ANCA/anti-PR3 disappeared. This first case of c-ANCA/anti-PR3 positive glomerulonephritis with a 'full-house' immunofluorescence pattern due to bacterial endocarditis underlines the importance of ruling out infection with ANCA positivity or kidney biopsy suggestive of lupus nephritis.

4.
Med Sci (Paris) ; 28(11): 963-9, 2012 Nov.
Artigo em Francês | MEDLINE | ID: mdl-23171900

RESUMO

Chronic granulomatous disease is a genetic disorder responsible for a defect in the NADPH oxidase of phagocytic cells. It impairs the oxidative burst necessary to the intracellular inactivation of microorganisms and predisposes to an increased risk of infections by various microorganisms, including fungi like Aspergillus spp. and other less frequently encountered or emerging fungal species. Here we review the genetic basis, pathogenesis and clinical presentation associated with fungal infections in chronic granulomatous disease as well as the current prophylaxis and newly available therapies.


Assuntos
Anti-Inflamatórios/uso terapêutico , Antifúngicos/uso terapêutico , Doença Granulomatosa Crônica/complicações , Micoses/etiologia , Animais , Aspergilose/etiologia , Aspergilose/imunologia , Aspergilose/terapia , Suscetibilidade a Doenças , Terapia Genética , Doença Granulomatosa Crônica/enzimologia , Doença Granulomatosa Crônica/epidemiologia , Doença Granulomatosa Crônica/imunologia , Doença Granulomatosa Crônica/cirurgia , Transplante de Células-Tronco Hematopoéticas , Humanos , Hospedeiro Imunocomprometido , Incidência , Indolamina-Pirrol 2,3,-Dioxigenase/metabolismo , Subpopulações de Linfócitos/imunologia , Camundongos , Micoses/epidemiologia , Micoses/imunologia , Micoses/prevenção & controle , Micoses/terapia , NADPH Oxidases/deficiência , NADPH Oxidases/genética , NADPH Oxidases/fisiologia , Neutrófilos/enzimologia , Neutrófilos/imunologia , Subunidades Proteicas , Explosão Respiratória , Triptofano/metabolismo
5.
Fungal Biol ; 115(1): 38-48, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21215953

RESUMO

On smallholder farms in the foothills of the Himalayan Mountains in Nepal, fungi of the Fusarium graminearum clade cause Gibberella ear rot of maize and contamination with the 8-ketotrichothecenes nivalenol and deoxynivalenol. Previous DNA marker analyses of the F. graminearum clade from maize in Nepal found a high level of genetic diversity but were limited in detail or scope. The present study incorporated a collection of 251 field strains from a wide geographic distribution in Nepal and utilized sequencing of the MAT1-1-3 gene of the mating type locus to determine the number and frequency of lineages and species of the F. graminearum clade. The frequency of nivalenol and deoxynivalenol chemotypes was determined by chemical analysis and by TRI13 deletion-marker analysis. We found that Gibberella ear rot of maize in Nepal is associated with a complex of species of the F. graminearum clade - mainly Fusarium asiaticum and Fusarium meridionale, but also Fusarium boothii and a putative new lineage, which we have designated the 'Nepal lineage'. Fusarium graminearum sensu stricto, which dominates in maize elsewhere in Asia and worldwide, was not detected in Nepal. Although nivalenol production has been associated experimentally with lower virulence in maize ear rot and wheat head blight, this collection of the F. graminearum clade from maize in Nepal is dominated (4:1) by nivalenol producers, suggesting that traits other than crop plant pathogenesis affect population structure in this complex agroecosystem.


Assuntos
Fusarium/isolamento & purificação , Fusarium/metabolismo , Variação Genética , Filogenia , Tricotecenos/biossíntese , Zea mays/microbiologia , Proteínas Fúngicas/genética , Fusarium/classificação , Fusarium/genética , Dados de Sequência Molecular , Nepal , Tricotecenos/química
6.
Mol Microbiol ; 74(5): 1128-42, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19843228

RESUMO

Trichothecenes are terpene-derived secondary metabolites produced by multiple genera of filamentous fungi, including many plant pathogenic species of Fusarium. These metabolites are of interest because they are toxic to animals and plants and can contribute to pathogenesis of Fusarium on some crop species. Fusarium graminearum and F. sporotrichioides have trichothecene biosynthetic genes (TRI) at three loci: a 12-gene TRI cluster and two smaller TRI loci that consist of one or two genes. Here, comparisons of additional Fusarium species have provided evidence that TRI loci have a complex evolutionary history that has included loss, non-functionalization and rearrangement of genes as well as trans-species polymorphism. The results also indicate that the TRI cluster has expanded in some species by relocation of two genes into it from the smaller loci. Thus, evolutionary forces have driven consolidation of TRI genes into fewer loci in some fusaria but have maintained three distinct TRI loci in others.


Assuntos
Evolução Molecular , Fusarium/genética , Tricotecenos/biossíntese , Animais , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Dados de Sequência Molecular , Família Multigênica , Filogenia , Toxina T-2/metabolismo
7.
J Agric Food Chem ; 57(11): 4478-84, 2009 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-19385595

RESUMO

Trichothecene biosynthesis research at the U.S. Department of Agriculture in Peoria, IL, began in 1984 in response to concerns about the use of trichothecenes in biological warfare, but continued as a long-term research program on the intractable problem of trichothecene contamination of human foods and animal feeds. Over 25 years, the trichothecene biosynthesis research group integrated natural product chemistry with fungal genetics and plant pathology in the laboratory and in the field to understand how and why Fusarium species make these complex and highly toxic metabolites. This interdisciplinary research placed trichothecenes in the unique class of fungal metabolites that not only cause mycotoxicoses in animals but also are virulence factors in plant disease.


Assuntos
Contaminação de Alimentos/análise , Fusarium/metabolismo , Micotoxinas/biossíntese , Doenças das Plantas/microbiologia , Tricotecenos/biossíntese , Triticum/microbiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fusarium/química , Fusarium/genética , Micotoxinas/química , Micotoxinas/genética , Tricotecenos/química , Tricotecenos/genética
8.
J Agric Food Chem ; 56(17): 7587-92, 2008 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-18690691

RESUMO

The chemotype of a microbial or plant species has traditionally been defined as its profile of natural products, and the genotype has been defined as its genetic constitution or DNA sequence. The purpose of this perspective is to discuss applications of DNA genotyping, particularly by polymerase chain reaction (PCR)-amplification methods, to predicting natural product chemotypes of fungi and plants of importance in food and agriculture. Development of PCR genotyping for predicting chemotypes will require collaboration between molecular biologists and natural product chemists, as well as community standards for reporting data. PCR genotyping should be validated by chemical analysis of individuals that represent the allelic diversity of the target gene in the population. To avoid misinterpretation, it is critical to differentiate data obtained by genotyping from data obtained by chemical analysis. The obvious and appropriate solution is to retain the established meanings of genotype and chemotype, both of which have been in use for half a century in the fields of genetics and natural product chemistry.


Assuntos
Fungos/química , Fungos/genética , Genótipo , Plantas/química , Plantas/genética , Alelos , Sistema Enzimático do Citocromo P-450/genética , DNA de Plantas/química , DNA de Plantas/genética , Fusarium/enzimologia , Fusarium/genética , Ligação Genética/genética , Reação em Cadeia da Polimerase , Tricotecenos/genética
9.
J Agric Food Chem ; 56(13): 5428-36, 2008 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-18533662

RESUMO

The fungus Fusarium graminearum (sexual stage Gibberella zeae) causes ear rot of maize (Zea mays) and contamination with the 8-ketotrichothecenes nivalenol (1) or 4-deoxynivalenol (2), depending on diversity of the fungal population for the 4-oxygenase gene (TRI13). To determine the importance of 1 and 2 in maize ear rot, a survey of naturally contaminated maize in Nepal was combined with experiments in the field and in a plant growth room. In the survey, 1 contamination was 4-fold more frequent than 2 contamination and 1-producers (TRI13) were isolated more than twice as frequently as 2-producers (Psi TRI13). In maize ear rot experiments, genetically diverse 1-producers and 2-producers caused ear rot and trichothecene contamination. Among strains with the same genetic background, however, 1-producers caused less ear rot and trichothecene contamination than did 2-producers. The high frequency of 1 contamination and the high virulence of many 1-producers are of concern because maize is a staple food of rural populations in Nepal and because 1 has proven to be more toxic than 2 to animals.


Assuntos
Fusarium/metabolismo , Micotoxinas/metabolismo , Doenças das Plantas/microbiologia , Tricotecenos/metabolismo , Zea mays/microbiologia , Frutas/microbiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fusarium/química , Fusarium/classificação , Fusarium/genética , Micotoxinas/química , Nepal , Oxigenases/genética , Oxigenases/metabolismo , Filogenia , Tricotecenos/química , Estados Unidos
10.
Mycol Res ; 111(Pt 7): 827-31, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17681226

RESUMO

Two species associated with the Gibberella fujikuroi species complex, G. circinata (the cause of pitch canker in pines) and G. subglutinans (avirulent on pine), were found to have limited interfertility in hybrid crosses. MAT idiomorphs, polymorphisms in the histone H3 gene, vegetative compatibility, and virulence phenotypes were used to verify recombination. The MAT idiomorphs appeared to be assorting independently, but the histone H3 haplotype was disproportionately represented by that of the G. subglutinans parent. Ninety-eight percent (45/46) of the progeny tested were vegetatively incompatible with both parents. All F(1) progeny were avirulent to pine, but a wide range of virulence was restored through a backcross to the virulent parent (G. circinata). Attempts at hybrid crosses using other isolate combinations were rarely successful (1/26). This limited interfertility supports retention of G. circinata and G. subglutinans as separate species, but offers opportunities to characterize the inheritance of virulence to pine.


Assuntos
Cruzamentos Genéticos , Gibberella/classificação , Gibberella/patogenicidade , Pinus/microbiologia , Doenças das Plantas/microbiologia , Recombinação Genética , Proteínas Fúngicas/genética , Genes Fúngicos Tipo Acasalamento , Gibberella/genética , Especificidade da Espécie , Esporos Fúngicos , Virulência/genética
11.
J Agric Food Chem ; 55(16): 6487-92, 2007 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-17630765

RESUMO

Many Fusarium species produce trichothecenes, sesquiterpene epoxides that differ in patterns of oxygenation and esterification at carbon positions C-3, C-4, C-7, C-8, and C-15. For the first comprehensive and quantitative comparison of the effects of oxygenation and esterification on trichothecene phytotoxicity, we tested 24 precursors, intermediates, and end products of the trichothecene biosynthetic pathway in an Arabidopsis thaliana detached leaf assay. At 100 microM, the highest concentration tested, only the trichothecene precursor trichodiene was nontoxic. Among trichothecenes, toxicity varied more than 200-fold. Oxygenation at C-4, C-8, C-7/8, or C-15 was, on average, as likely to decrease as to increase toxicity. Esterification at C-4, C-8, or C-15 generally increased toxicity. Esterification at C-3 increased toxicity in one case and decreased toxicity in three of eight cases tested. Thus, the increase in structural complexity along the trichothecene biosynthetic pathway in Fusarium is not necessarily associated with an increase in phytotoxicity.


Assuntos
Arabidopsis/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Tricotecenos/química , Tricotecenos/toxicidade , Esterificação , Hidroxilação , Relação Estrutura-Atividade , Tricotecenos/biossíntese
12.
J Agric Food Chem ; 54(19): 7383-90, 2006 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-16968109

RESUMO

Fusarium subglutinans causes maize ear rot and contaminates grain with the mycotoxin moniliformin. Previous DNA sequence analysis divided F. subglutinans from maize into two cryptic species, designated groups 1 and 2. Here, it was determined whether the two groups differ in the agriculturally important traits of virulence on maize and moniliformin production in planta. Thirty-seven strains from U.S. maize were assigned to groups 1 and 2 by DNA sequence analysis. In field tests, all strains were highly virulent on maize inbred B73 and four maize hybrids. In planta, 82% of group 1 strains and 25% of group 2 strains produced high levels (100-1500 microg/g) of moniliformin. All group 2 strains from more northern states produced little or no moniliformin (0-5 microg/g). These data indicate that moniliformin production is highly variable in F. subglutinans from U.S. maize and that production may not be required for the fungus to cause maize ear rot.


Assuntos
Ciclobutanos/análise , Fusarium/metabolismo , Doenças das Plantas/microbiologia , Zea mays/microbiologia , Ciclobutanos/metabolismo , Fusarium/isolamento & purificação , Sementes/química , Sementes/microbiologia , Zea mays/química
13.
J Agric Food Chem ; 54(6): 2424-30, 2006 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-16536629

RESUMO

Fumonisins are polyketide-derived mycotoxins produced by the maize pathogen Fusarium verticillioides. Previous analyses identified naturally occurring variants of the fungus that are deficient in fumonisin C-10 hydroxylation or that do not produce any fumonisins. In the current study, gene deletion and genetic complementation analyses localized the C-10 hydroxylation deficiency to a cytochrome P450 monooxygenase gene in the fumonisin biosynthetic gene (FUM) cluster. Sequence analysis indicated that the hydroxylation deficiency resulted from a single nucleotide insertion that caused a frame shift in the coding region of the gene. Genetic complementation localized the fumonisin-nonproduction phenotype to the polyketide synthase gene in the FUM cluster, and sequence analysis indicated that the nonproduction phenotype resulted from a nucleotide substitution, which introduced a premature stop codon in the coding region. These results provide the first direct evidence that altered fumonisin production phenotypes of naturally occurring F. verticillioides variants can result from single point mutations in the FUM cluster.


Assuntos
Fumonisinas/química , Fumonisinas/metabolismo , Fusarium/genética , Zea mays/microbiologia , Fusarium/enzimologia , Fusarium/metabolismo , Variação Genética , Oxigenases de Função Mista/genética , Fenótipo , Mutação Puntual
14.
Phytochemistry ; 66(20): 2474-80, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16198380

RESUMO

Landraces of maize (Zea mays ssp. mays) and its wild teosinte relatives (Zea mays spp. parviglumis and mexicana) were surveyed for sensitivity to fumonisin B(1), a phytotoxin produced by the maize pathogen Gibberella moniliformis. Only two of 42 Z. mays samples were highly insensitive to FB(1) (ED(50) = ca. 200 microM). The teosintes and 76% of the maize landraces were moderately or highly sensitive to FB(1) (ED(50) < or = 30 microM), which indicates that FB(1) sensitivity is likely to be an ancestral trait in Z. mays. F(1) generations derived from crosses between FB(1)-sensitive maize inbred B73 and insensitive landraces were significantly less sensitive than B73. Thus, our data indicate that FB(1)-insensitivity is a relatively rare but heritable trait in maize. We also report the sensitivity of maize to other Gibberella toxins - beauvericin, diacetoxyscirpenol, and moniliformin.


Assuntos
Fumonisinas/farmacologia , Zea mays/efeitos dos fármacos , Zea mays/genética , Ciclobutanos/farmacologia , Depsipeptídeos/farmacologia , Predisposição Genética para Doença , Genética Populacional , Gibberella/patogenicidade , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia
16.
J Agric Food Chem ; 52(20): 6341-6, 2004 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-15453711

RESUMO

Fusarium graminearum causes wheat head blight and contaminates grain with the trichothecenes 4-deoxynivalenol and nivalenol. Sequence analysis of trichothecene genes indicates that nivalenol production is the ancestral trait; however, deoxynivalenol producers occur worldwide and predominate in North and South America and in Europe. Analysis of a large field population (>500 strains) from Nepal identified three groups that were both genetically distinct and polymorphic for trichothecene production: SCAR1 comprising 95% deoxynivalenol producers, SCAR2 comprising 94% nivalenol producers, and SCAR3/5 comprising 34% deoxynivalenol producers/63% nivalenol producers. The ability to cause wheat head blight differed between SCAR groups and trichothecene chemotypes: deoxynivalenol producers were more virulent than nivalenol producers across all three SCAR groups and within the SCAR3/5 genetic background. These data support the hypothesis that production of deoxynivalenol rather than nivalenol confers a selective advantage to this important wheat pathogen.


Assuntos
Fusarium/genética , Fusarium/patogenicidade , Doenças das Plantas/microbiologia , Tricotecenos/biossíntese , Triticum/microbiologia , Variação Genética , Nepal
17.
Pest Manag Sci ; 59(6-7): 629-42, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12846313

RESUMO

Mycotoxins (ie toxins produced by molds) are fungal metabolites that can contaminate foods and feeds and cause toxic effects in higher organisms that consume the contaminated commodities. Therefore, mycotoxin contamination of foods and feeds results is a serious food safety issue and affects the competitiveness of US agriculture in both domestic and export markets. This article highlights research accomplished by Agricultural Research Service (ARS) laboratories on control of pre-harvest toxin contamination by using biocontrol, host-plant resistance enhancement and integrated management systems. Emphasis is placed on the most economically relevant mycotoxins, namely aflatoxins produced by Aspergillus flavus, Link, trichothecenes produced by various Fusarium spp and fumonisins produced by F verticillioides. Significant inroads have been made in establishing various control strategies such as development of atoxigenic biocontrol fungi that can outcompete their closely related, toxigenic cousins in field environments, thus reducing levels of mycotoxins in the crops. Potential biochemical and genetic resistance markers have been identified in crops, particularly in corn, which are being utilized as selectable markers in breeding for resistance to aflatoxin contamination. Prototypes of genetically engineered crops have been developed which: (1) contain genes for resistance to the phytotoxic effects of certain trichothecenes, thereby helping reduce fungal virulence, or (2) contain genes encoding fungal growth inhibitors for reducing fungal infection. Gene clusters housing the genes governing formation of trichothecenes, fumonisins and aflatoxins have been elucidated and are being targeted in strategies to interrupt the biosynthesis of these mycotoxins. Ultimately, a combination of strategies using biocompetitive fungi and enhancement of host-plant resistance may be needed to adequately prevent mycotoxin contamination in the field. To achieve this, plants may be developed that resist fungal infection and/or reduce the toxic effects of the mycotoxins themselves, or interrupt mycotoxin biosynthesis. This research effort could potentially save affected agricultural industries hundreds of millions of dollars during years of serious mycotoxin outbreaks.


Assuntos
Produtos Agrícolas/crescimento & desenvolvimento , Fungos/crescimento & desenvolvimento , Micotoxinas/metabolismo , Controle Biológico de Vetores/métodos , United States Department of Agriculture , Aspergillus/crescimento & desenvolvimento , Produtos Agrícolas/microbiologia , Produtos Agrícolas/parasitologia , Fusarium/crescimento & desenvolvimento , Imunidade Inata/efeitos dos fármacos , Micotoxinas/toxicidade , Doenças das Plantas/microbiologia , Doenças das Plantas/parasitologia , Estados Unidos
18.
Annu Rev Phytopathol ; 41: 177-98, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12651961

RESUMO

Gibberella species are destructive plant pathogens, although many are more familiar under their Fusarium anamorph names. The recent synthesis of phylogenetic, biological, and morphological species approaches has revitalized taxonomy of a genus that was first described almost 200 years ago. Twelve sexual species of Gibberella of agricultural importance were selected for this review to represent phylogenetic, biological, and chemical diversity of the genus. Even closely related Gibberella species can differ in reproductive mode, geographic and host distribution, plant pathogenesis, and production of toxins and other biologically active metabolites. Gibberella species have proven amenable to meiotic and molecular genetic analysis; A complete genome sequence of G. zeae should soon be available. Combining gene disruption strategies with new genomics technologies for expression profiling should help plant pathologists to understand the pathological and evolutionary significance of biological and chemical diversity in Gibberella and to identify novel strategies for disease control.


Assuntos
Gibberella/classificação , Gibberella/patogenicidade , Plantas/microbiologia , Especificidade da Espécie
19.
Fungal Genet Biol ; 38(2): 237-49, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12620260

RESUMO

Fumonisins are mycotoxins produced by the maize pathogen Gibberella moniliformis and are associated with cancer in rodents. In this study, we determined the nucleotide sequence of a 75-kb region of G. moniliformis DNA and identified 18 heretofore undescribed genes flanking a cluster of five previously identified fumonisin biosynthetic (FUM) genes. Ten of the newly identified genes downstream of the cluster were coregulated with FUM genes and exhibited patterns of expression that were correlated with fumonisin production. BLASTX analyses indicated that the predicted functions of proteins encoded by the 10 genes were consistent with activities expected for fumonisin biosynthesis or self-protection. These data indicate that the 10 newly identified genes and the previously identified FUM genes constitute a fumonisin biosynthetic gene cluster. Disruption of two of the new genes, encoding longevity assurance factors, had no apparent effect on fumonisin production, but disruption of a third, encoding an ABC transporter, had a subtle effect on ratios of fumonisins produced.


Assuntos
Fumonisinas/metabolismo , Gibberella/genética , Família Multigênica , Sequência de Aminoácidos , Northern Blotting , Southern Blotting , Gibberella/metabolismo , Íntrons , Dados de Sequência Molecular , Alinhamento de Sequência , Análise de Sequência de DNA
20.
Fungal Genet Biol ; 36(3): 224-33, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12135578

RESUMO

Species of the genus Fusarium produce a great diversity of agriculturally important trichothecene toxins that differ from each other in their pattern of oxygenation and esterification. T-2 toxin, produced by Fusarium sporotrichioides, and nivalenol (NIV), produced by some strains of F. graminearum, contain an oxygen at the C-4 position. Deoxynivalenol (DON), produced by other strains of F. graminearum, lacks a C-4 oxygen. NIV and DON are identical except for this difference, whereas T-2 differs from these trichothecenes at three other carbon positions. Sequence and Northern analyses of the F. sporotrichioides genomic region upstream of the previously described core trichothecene gene cluster have extended the cluster by two genes: TRI13 and TRI14. TRI13 shares significant similarity with the cytochrome P-450 class of enzymes, but TRI14 does not share similarity with any previously characterized proteins. Gene disruption and fermentation studies in F. sporotrichioides indicate that TRI13 is required for the addition of the C-4 oxygen of T-2 toxin, but that TRI14 is not required for trichothecene biosynthesis. PCR and sequence analyses indicate that the TRI13 homolog is functional in NIV-producing strains of F. graminearum but nonfunctional in DON-producing strains of the fungus. These genetic observations are consistent with chemical observations that biosynthesis of T-2 toxin and NIV requires a C-4 hydroxylase while biosynthesis of DON does not.


Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Fusarium/genética , Tricotecenos/genética , Sequência de Aminoácidos , Sequência de Bases , Códon de Iniciação , Inibidores das Enzimas do Citocromo P-450 , Sistema Enzimático do Citocromo P-450/genética , DNA Fúngico/análise , DNA Fúngico/genética , DNA Intergênico/genética , Fusarium/classificação , Fusarium/metabolismo , Genes Fúngicos , Dados de Sequência Molecular , Família Multigênica/genética , Filogenia , Biossíntese de Proteínas , Análise de Sequência de DNA , Toxina T-2/biossíntese , Toxina T-2/genética , Tricotecenos/biossíntese , Tricotecenos/química
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