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1.
Cells ; 9(10)2020 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-33092216

RESUMO

Black spot disease, caused by Alternaria brassicicola in Brassica species, is one of the most devastating diseases all over the world, especially since there is no known fully resistant Brassica cultivar. In this study, the visualization of black spot disease development on Brassica oleracea var. capitata f. alba (white cabbage) leaves and subsequent ultrastructural, molecular and physiological investigations were conducted. Inter- and intracellular hyphae growth within leaf tissues led to the loss of host cell integrity and various levels of organelle disintegration. Severe symptoms of chloroplast damage included the degeneration of chloroplast envelope and grana, and the loss of electron denseness by stroma at the advanced stage of infection. Transcriptional profiling of infected leaves revealed that photosynthesis was the most negatively regulated biological process. However, in infected leaves, chlorophyll and carotenoid content did not decrease until 48 hpi, and several chlorophyll a fluorescence parameters, such as photosystem II quantum yield (Fv/Fm), non-photochemical quenching (NPQ), or plant vitality parameter (Rdf) decreased significantly at 24 and 48 hpi compared to control leaves. Our results indicate that the initial stages of interaction between B. oleracea and A. brassicicola are not uniform within an inoculation site and show a complexity of host responses and fungal attempts to overcome host cell defense mechanisms. The downregulation of photosynthesis at the early stage of this susceptible interaction suggests that it may be a part of a host defense strategy, or, alternatively, that chloroplasts are targets for the unknown virulence factor(s) of A. brassicicola. However, the observed decrease of photosynthetic efficiency at the later stages of infection is a result of the fungus-induced necrotic lesion expansion.


Assuntos
Alternaria/ultraestrutura , Brassica/genética , Brassica/microbiologia , Regulação para Baixo , Interações Hospedeiro-Patógeno/genética , Fotossíntese , Doenças das Plantas/microbiologia , Transcrição Genética , Alternaria/fisiologia , Brassica/fisiologia , Brassica/ultraestrutura , Clorofila A/metabolismo , Cloroplastos/metabolismo , Cloroplastos/ultraestrutura , Suscetibilidade a Doenças , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Células do Mesofilo/microbiologia , Células do Mesofilo/ultraestrutura , Fotossíntese/genética , Folhas de Planta/microbiologia , Folhas de Planta/ultraestrutura , Fatores de Tempo
2.
PLoS One ; 13(6): e0199466, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29944684

RESUMO

Endophytic strains were isolated from different parts of a healthy "Dongzao" jujube (Ziziphus jujuba Mill. 'Dongzao') to find biocontrol agents against jujube shrunken-fruit disease caused by Alternaria alternata. The strains were screened using A. alternata strain CN193 as the target pathogen. The nutrient competition for all isolates was studied using the dual culture, and their inhibitive capability was tested by measuring the inhibition width of filter paper disks with filtrate. Influence of filtrate from the selected strains with strong inhibition of mycelial growth on spore germination was studied with hanging drop method on concavity slides. Colonization in the jujube leaves was assayed using a rifampicin-resistant mutant of strain St-zn-34 as the screening marker. Strains were identified based on their morphological, physiological, and biochemical characteristics, 16S rDNA sequencing, and phylogenetic analysis. A total of 81 endophytic strains were isolated from the stems, leaves, flowers, and fruits of winter jujube. Among these isolates, 14 strains showed strong antagonism against A. alternata. Further study showed that the filtrate of strains St-zn-9 and St-zn-34 could inhibit the mycelial growth of A. alternata, and the widths of their inhibition zone reached 6.14±0.03 mm and 8.27±0.09 mm, respectively. However, strain St-zn-34 showed stronger inhibition on spore germination than strain St-zn-9. St-zn-34 could significantly reduce the spore germination rate of A. alternata, and the spore did not germinate at all or the germ tube was very short. A rifampicin resistant-derivative of wild-type strain St-zn-34, which was designated as St-zn-34r, was obtained by transferring the strains to media with stepwise-increased rifampicin. Colonization assays indicated that St-zn-34r could colonize in jujube leaves, and the population of St-zn-34r was 1.2×103 CFU/g FW after inoculation for 30 days. Except for its salt tolerance, St-zn-34 was the closest to those of Bacillus subtilis. Thus, the strain was identified as B. subtilis.


Assuntos
Alternaria/fisiologia , Endófitos/fisiologia , Controle Biológico de Vetores , Doenças das Plantas/microbiologia , Ziziphus/microbiologia , Alternaria/crescimento & desenvolvimento , Alternaria/ultraestrutura , Contagem de Colônia Microbiana , DNA Ribossômico/genética , Fermentação , Germinação , Filogenia , Dinâmica Populacional , Esporos Fúngicos/fisiologia
3.
Ann Pathol ; 36(4): 245-51, 2016 Aug.
Artigo em Francês | MEDLINE | ID: mdl-27475007

RESUMO

Rhino-sinusal infections are serious diseases and possibly lethal. When they are invasive, we easily discuss apergilloses and mucormycoses. The confirmation of the diagnosis of mucormycosis need an extensive surgery for precise histopathological and mycological evaluation. The pathologist may be faced to other rare mycoses such as phaeohyphomycoses, which present different morphological features than mucormycoses and Aspergillus. Once the diagnosis is established, an appropriate antifungal treatment is quickly started. The aim of our work is to report two observations of phaeohyphomycoses, to describe their histopathological features, to discuss complementary diagnostic methods and to present the main differential diagnoses.


Assuntos
Alternaria/isolamento & purificação , Alternariose/microbiologia , Feoifomicose/microbiologia , Rinite/microbiologia , Sinusite/microbiologia , Adulto , Alternaria/ultraestrutura , Alternariose/diagnóstico , Alternariose/patologia , Alternariose/terapia , Anfotericina B/administração & dosagem , Anfotericina B/uso terapêutico , Antifúngicos/uso terapêutico , Terapia Combinada , Desbridamento , Diagnóstico Diferencial , Diagnóstico Precoce , Evolução Fatal , Feminino , Humanos , Lipossomos , Mastoidite/tratamento farmacológico , Mastoidite/microbiologia , Mastoidite/cirurgia , Feoifomicose/diagnóstico , Feoifomicose/patologia , Feoifomicose/terapia , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos , Rinite/diagnóstico , Rinite/patologia , Rinite/terapia , Choque Séptico/etiologia , Sinusite/diagnóstico , Sinusite/patologia , Sinusite/terapia
5.
J Sci Food Agric ; 94(7): 1403-8, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-25525652

RESUMO

BACKGROUND: Many essential oils were reported to be used as natural, environmental friendly antimicrobial agents. The antifungal activity in vitro and in vivo of an essential oil extracted from Chinese local Laurus nobilis leaves against Alternaria alternata has been studied. RESULT: The main components of the essential oil were investigated by means of gas chromatography­mass spectrometry and 14 components were identified. The main ones were eugenol, caryophyllene and cinnamaldehyde. The antifungal test showed that at 800 µg mL−1 of L. nobilis oil completely inhibited the growth of A. alternata. In addition, the conidial germination of the pathogen was significantly inhibited at 200 µgmL−1, and the weight of mycelia efficiently decreased at 500 µgmL−1. The in vivo assay indicated that 500 µg mL−1 L. nobilis oil was effective in protecting cherry tomatoes (Lycopersicon esculentum)from infection of A. alternata, with an inhibition ratio of 33.9%. Scanning electron microscopy observations of the pathogen revealed significant morphological alterations in the hyphae. CONCLUSION: This work suggested that L. nobilis oil could be used as a potential fungicide to control the post-harvest disease caused by A. alternata.


Assuntos
Alternaria/efeitos dos fármacos , Frutas/microbiologia , Fungicidas Industriais/farmacologia , Laurus/química , Lycopersicon esculentum/microbiologia , Óleos Voláteis/farmacologia , Alternaria/fisiologia , Alternaria/ultraestrutura , Conservação de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Hifas/fisiologia , Hifas/ultraestrutura , Esporos Fúngicos/fisiologia
6.
Med Mycol ; 52(2): 202-10, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24576997

RESUMO

Many fungi use membrane vesicles to transport complex molecules across their cell walls. Like mammalian exosomes, fungal vesicles contain lipids, proteins, and polysaccharides, many of which are associated with virulence. Here we identify and characterize extracellular vesicles (EVs) in Alternaria infectoria, a ubiquitous, environmental filamentous fungus that is also an opportunistic human pathogen. Examination of the A. infectoria EVs revealed a morphology similar to that of vesicles described in other fungal species. Of note, proteomic analysis detected a reduced number of vesicle-associated proteins. There were two prevalent categories among the 20 identified proteins, including the polysaccharide metabolism group, probably related to plant host invasion or biosynthesis/degradation of cell wall components, and the nuclear proteins, especially DNA repair enzymes. We also found enzymes related to pigment synthesis, adhesion to the host cell, and trafficking of vesicles/organelles/molecules. This is the first time EV secretions have been identified in a filamentous fungus. We believe that these vesicles might have a role in virulence.


Assuntos
Alternaria/metabolismo , Exossomos/metabolismo , Alternaria/ultraestrutura , Exossomos/química , Exossomos/ultraestrutura , Proteínas Fúngicas/análise , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Proteoma/análise , Fatores de Virulência/análise
7.
Pest Manag Sci ; 70(12): 1815-22, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24408227

RESUMO

BACKGROUND: In previous studies, the extract from Anadenanthera colubrina was active against Alternaria alternata in vitro and reduced the disease caused by this fungus on Murcott tangor fruits to levels that have been obtained using commercial fungicides. Therefore, the goal of the present work was to isolate and identify the active substances in this extract and identify in silico their protein target in the fungus. RESULTS: The bioguided fractionation of the methanol extract from the fruits of A. colubrina resulted in the isolation of ß-sitosterol and ß-sitosteryl linoleate, which had minimal inhibitory concentrations (MICs) of 250 and 500 µg mL(-1) , respectively, against A. alternata. Under the same conditions, the MICs for two commercial fungicides were 1250 and 19 µg mL(-1) . In silico studies showed that these steroidal substances bind well to oxysterol-binding proteins from Saccharomyces cerevisiae. CONCLUSION: ß-Sitosterol and ß-sitosteryl linoleate, produced by A. colubrina, are active against A. alternata. In silico studies suggest that these substances may act by binding to oxysterol-binding proteins. Therefore, both substances and these proteins have potential use in the development of new steroidal structures and analogues to control the disease caused by A. alternata.


Assuntos
Alternaria/efeitos dos fármacos , Alternaria/crescimento & desenvolvimento , Fabaceae/química , Fungicidas Industriais/farmacologia , Doenças das Plantas/prevenção & controle , Extratos Vegetais/farmacologia , Sitosteroides/farmacologia , Alternaria/ultraestrutura , Citrus/microbiologia , Simulação por Computador , Extratos Vegetais/uso terapêutico , Receptores de Esteroides/metabolismo , Sitosteroides/isolamento & purificação
8.
Mol Plant Pathol ; 14(4): 365-78, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23279187

RESUMO

Black spot disease, Alternaria alternata Japanese pear pathotype, produces the host-specific toxin AK-toxin, an important pathogenicity factor. Previously, we have found that hydrogen peroxide is produced in the hyphal cell wall at the plant-pathogen interaction site, suggesting that the fungal reactive oxygen species (ROS) generation machinery is important for pathogenicity. In this study, we identified two NADPH oxidase (NoxA and NoxB) genes and produced nox disruption mutants. ΔnoxA and ΔnoxB disruption mutants showed increased hyphal branching and spore production per unit area. Surprisingly, only the ΔnoxB disruption mutant compromised disease symptoms. A fluorescent protein reporter assay revealed that only NoxB localized at the appressoria during pear leaf infection. In contrast, both NoxA and NoxB were highly expressed on the cellulose membrane, and these Nox proteins were also localized at the appressoria. In the ΔnoxB disruption mutant, we could not detect any necrotic lesions caused by AK-toxin. Moreover, the ΔnoxB disruption mutant did not induce papilla formation on pear leaves. Ultrastructural analysis revealed that the ΔnoxB disruption mutant also did not penetrate the cuticle layer. Moreover, ROS generation was not essential for penetration, suggesting that NoxB may have an unknown function in penetration. Taken together, our results suggest that NoxB is essential for aggressiveness and basal pathogenicity in A. alternata.


Assuntos
Alternaria/enzimologia , Alternaria/patogenicidade , Especificidade de Hospedeiro , Micotoxinas/biossíntese , NADPH Oxidases/metabolismo , Pyrus/microbiologia , Esporos Fúngicos/enzimologia , 3,3'-Diaminobenzidina/metabolismo , Alternaria/genética , Alternaria/ultraestrutura , Clonagem Molecular , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Genes Fúngicos/genética , Humanos , Peróxido de Hidrogênio/metabolismo , Japão , Mutação/genética , Micélio/crescimento & desenvolvimento , NADPH Oxidases/genética , Fenótipo , Filogenia , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Folhas de Planta/ultraestrutura , Transporte Proteico , Esporos Fúngicos/ultraestrutura
9.
Mol Plant Pathol ; 12(7): 653-65, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21726368

RESUMO

Fungi respond and adapt to different environmental stimuli via signal transduction systems. We determined the function of a yeast SLT2 mitogen-activated protein (MAP) kinase homologue (AaSLT2) in Alternaria alternata, the fungal pathogen of citrus. Analysis of the loss-of-function mutant indicated that AaSLT2 is required for the production of a host-selective toxin, and is crucial for fungal pathogenicity. Moreover, the A. alternata slt2 mutants displayed hypersensitivity to cell wall-degrading enzymes and chemicals such as Calcofluor white and Congo red. This implicates an important role of AaSLT2 in the maintenance of cell wall integrity in A. alternata. The A. alternata slt2 mutants were also hypersensitive to a heteroaromatic compound, 2-chloro-5-hydroxypyridine, and a plant growth regulator, 2,3,5-triiodobenzoic acid. Developmentally, the AaSLT2 gene product was shown to be critical for conidial formation and hyphal elongation. Compared with the wild-type, the mutants produced fewer but slightly larger conidia with less transverse septae. The mutants also accumulated lower levels of melanin and chitin. Unlike the wild-type progenitor, the A. alternata slt2 mutants produced globose, swollen hyphae that did not elongate in a straight radial direction. All defective phenotypes in the mutant were restored by transformation and expression of a wild-type copy of AaSLT2 under the control of its endogenous promoter. This study highlights an important role of the AaSLT2 MAP kinase-mediated signalling pathway, regulating diverse physiological, developmental and pathological functions, in the tangerine pathotype of A. alternata.


Assuntos
Alternaria/metabolismo , Alternaria/patogenicidade , Citrus/microbiologia , Melaninas/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Alternaria/genética , Alternaria/ultraestrutura , Quitina/metabolismo , Farmacorresistência Fúngica/genética , Farmacorresistência Fúngica/fisiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Proteínas Quinases Ativadas por Mitógeno/genética , Mutação , Transdução de Sinais , Esporos Fúngicos/efeitos dos fármacos , Virulência
10.
Rev Iberoam Micol ; 28(4): 173-8, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21635961

RESUMO

BACKGROUND: Alternaria alternata causes the Alternaria brown spot disease (ABS) in many tangerines and their hybrids worldwide. Plant extracts offer an alternative method for controlling this disease, which control is based on chemical fungicides. AIMS: To identify plant species with antifungal properties against A. alternata, the causal agent of the ABS. METHODS: Plant extracts prepared from leaves, barks, flowers, and stalks collected from 105 plant species in the State of Minas Gerais, Brazil, were tested for activity against the fungus A. alternata in vitro and in vivo. RESULTS: The most promising extract was obtained from Anadenanthera colubrina, which reduced the disease on Murcott tangor fruits to levels obtained with commercial fungicides. Artemisia annua, Cariniana estrelensis, Ficus carica, and Ruta graveolens presented moderate in vitro antifungal activity, but no effects were observed on the disease when the extracts were applied to fruits inoculated with the fungus. Besides, A. colubrina was the most active extract against A. alternata in the in vitro assay. CONCLUSIONS: The results obtained in the in vitro and in vivo assays suggested that the fungal growth test, which uses 96-well polypropylene plates, seems to be appropriate for selecting potential plant species for testing new methods to control ABS.


Assuntos
Alternaria/efeitos dos fármacos , Alternaria/crescimento & desenvolvimento , Citrus/microbiologia , Doenças das Plantas/prevenção & controle , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Alternaria/ultraestrutura , Microscopia Eletrônica de Varredura
11.
J Sci Food Agric ; 91(9): 1630-7, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21445868

RESUMO

BACKGROUND: Antifungal proteins (AFP) help plants to combat phytopathogenic fungi and thus protect plants from the devastating damage caused by fungal infections and prevent massive economic losses. To date, several proteins with antibacterial and/or antifungal properties have been isolated and characterized from different plant species and tissues; however, there are no reports concerning the antifungal peptide from foxtail millet seeds. RESULTS: An antifungal peptide with a molecular mass of 26.9 kDa was isolated from dry seeds of the foxtail millet (Setaria italica (L.) Beauv.), using a procedure that involved four chromatographic steps. The antifungal peptide was adsorbed on CM-Sepharose, Affi-gel blue gel and Superdex 75. It was further purified by C(18) reverse-phase high-performance liquid chromatography and submitted for analysis of peptide mass fingerprint. The Mascot peptide mass fingerprint of the isolated protein hit no existing protein (score >60), and it was proved to be a novel antifungal peptide. It inhibited mycelial growth in Alternaria alternate with an IC(50) of 1.3 µmol L(-1) , and it also exhibited antifungal activity against Trichoderma viride, Botrytis cinerea and Fusarium oxysporum. Transmission electron microscopy of mold forms of Alternaria alternate after incubation with 20 µg mL(-1) of the antifungal protein for 48 h revealed marked ultrastructural changes in the fungus. CONCLUSION: A novel antifungal peptide with high potency was isolated from foxtail millet seeds.


Assuntos
Alternaria/efeitos dos fármacos , Antifúngicos/farmacologia , Peptídeos/farmacologia , Proteínas de Plantas/farmacologia , Setaria (Planta)/química , Alternaria/crescimento & desenvolvimento , Alternaria/ultraestrutura , Antifúngicos/isolamento & purificação , Cromatografia/métodos , Fungos/efeitos dos fármacos , Concentração Inibidora 50 , Peso Molecular , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Mapeamento de Peptídeos/métodos , Peptídeos/isolamento & purificação , Proteínas de Plantas/isolamento & purificação , Sementes/química
12.
Mycologia ; 103(1): 94-100, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-20943568

RESUMO

During routine wheat disease surveys in Hungary in 2007 Alternaria was isolated from leaf samples collected in Debrecen. Macro- and micro-morphological examinations and ITS sequence analyses indicated that the isolates represented a new Alternaria species, which we described as A. hungarica. The usually solitary conidia of A. hungarica resemble those of A. mouchaccae and A. molesta. However growth and sporulation pattern are more like those of A. geniostomatis and A. soliaridae. Phylogenetic analysis of ITS sequences indicated that this new species can be distinguished from all other examined Alternaria and Embellisia species. Pathogenicity tests indicated that A. hungarica can be considered a minor pathogen of wheat.


Assuntos
Alternaria/isolamento & purificação , Doenças das Plantas/microbiologia , Triticum/microbiologia , Alternaria/genética , Alternaria/ultraestrutura , Sequência de Bases , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Hungria , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , RNA Ribossômico 5,8S/química , RNA Ribossômico 5,8S/genética , Alinhamento de Sequência
13.
Phytopathology ; 100(9): 840-7, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20701480

RESUMO

In the Japanese pear pathotype of Alternaria alternata, H2O2 is generated solely from penetration pegs and not from other portions of subcuticular hyphae within the pectin layers of host leaves. A close association between H2O2 generation and fungal aggressiveness is expected because the pegs are important for fungal penetration into the host epidermis. To determine the potential role of reactive oxygen species in microbial pathogenicity, we studied the inhibitory effects of the antioxidant reagent ascorbic acid and the NADPH oxidase inhibitor diphenylene iodonium on infection of the pathogen. In our study, we showed H2O2 generation to be inhibited by inoculation with the mixture of ascorbic acid or diphenylene iodonium and spores at the pegs in the spore-inoculated host leaves. The decrease of generation in the pegs resulted in penetration failure, indicating that H2O2 generation probably contributed to strengthening of the penetration and probably was recruited by NADPH oxidase.


Assuntos
Alternaria/fisiologia , Antioxidantes/farmacologia , Ácido Ascórbico/farmacologia , Doenças das Plantas/microbiologia , Pyrus/microbiologia , Alternaria/ultraestrutura , Interações Hospedeiro-Parasita , Peróxido de Hidrogênio/metabolismo , Hifas/efeitos dos fármacos , Hifas/fisiologia , Oniocompostos/farmacologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/microbiologia , Proteínas de Plantas/antagonistas & inibidores , Proteínas de Plantas/metabolismo , Espécies Reativas de Oxigênio
15.
Yakugaku Zasshi ; 127(4): 773-7, 2007 Apr.
Artigo em Japonês | MEDLINE | ID: mdl-17409710

RESUMO

The efficacy of chlorine dioxide (ClO(2)) gas at very low concentrations for hyphal growth of Alternaria alternata related to fungal allergy was evaluated using a fungus detector. The fungus detector is a plastic sheet with a drop of spore-suspending medium, and it makes possible clear observations of hyphal growth with a light microscope. ClO(2) gas (average 0.075 ppm, 0.21 microg/l) inhibited hyphal growth of the fungus, but not germination of fungal spores. The hyphal length was more than 1780 mum under air conditions (control) and 49+/-17 microm under ClO(2) gas conditions for 72 h. According to the international chemical safety card, threshold limit values for ClO(2) gas are 0.1 ppm as an 8-h time-weight average and 0.3 ppm as a 15 min short-term exposure limit. From these data, we propose that treatment with ClO(2) gas at very low concentrations in space is a useful tool for the growth inhibition of fungi in the fields of food, medicine, etc. without adverse effects.


Assuntos
Alternaria/crescimento & desenvolvimento , Compostos Clorados/farmacologia , Óxidos/farmacologia , Ar Condicionado , Alternaria/ultraestrutura , Depressão Química , Relação Dose-Resposta a Droga , Gases , Microscopia , Fatores de Tempo
16.
Mycopathologia ; 163(3): 183-90, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17356789

RESUMO

The species Trichoderma harzianum was analyzed as possible biocontrol agent of Alternaria alternata under different environmental conditions (water activity and temperature). The strains were analyzed macroscopically to obtain the Index of Dominance. The analysis was completed using two microscopic techniques. T. harzianum showed dominance on contact over A. alternata at all testing temperatures and water activities tested except at 0.95 a(w) and 15 degrees C, at which T. harzianum inhibited A. alternata at a distance. Biocontrol was governed by different mechanisms such as competition for space and nutrients, mycoparasitism, and possible antibiosis. Temperature and water activity significantly influenced fungal growth rate.


Assuntos
Alternaria/crescimento & desenvolvimento , Oryza/microbiologia , Controle Biológico de Vetores , Trichoderma/crescimento & desenvolvimento , Alternaria/ultraestrutura , Antibiose , Doenças das Plantas/microbiologia , Temperatura , Trichoderma/química , Trichoderma/ultraestrutura , Água
17.
J Immunol Methods ; 316(1-2): 167-70, 2006 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-17028015

RESUMO

Fungal allergens are present in viable and non-viable conidia, hyphae and fungal fragments. It has been shown that large quantities of allergen are released from conidia during germination. We used a gold immunolabelling technique and field emission scanning electron microscopy to examine the allergen release from Alternaria alternata conidia. Immunolabelling was associated with the hyphal tip and amorphous matter associated with the emerging hyphae. Non-specific antibody controls showed no labelling associated with germinating fungi. This suggests that material released from hyphae may be an additional source of fungal allergens.


Assuntos
Alérgenos/isolamento & purificação , Alternaria/química , Proteínas Fúngicas/isolamento & purificação , Imuno-Histoquímica/métodos , Microscopia Eletrônica de Varredura/métodos , Alérgenos/ultraestrutura , Alternaria/imunologia , Alternaria/ultraestrutura , Antígenos de Plantas , Proteínas Fúngicas/ultraestrutura , Humanos
18.
Mycopathologia ; 160(2): 117-23, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16170606

RESUMO

Here we report a case of cutaneous alternariosis in a 74-year-old man treated by corticotherapy for myasthenia, and presenting with papular, crusted lesions on the left elbow and the right knee. Histological examination of the biopsy specimens showed fungal hyphae associated with round-shaped cells which were highly suggestive of alternariosis. Mycological culture allowed the isolation of a dematiaceous fungus which was identified as a member of the Alternaria infectoria species-group. This was confirmed by PCR amplification and sequencing of the internal transcribed spacer domain of the gene encoding nuclear ribosomal DNA and of the mitochondrial small subunit ribosomal DNA domain. The fungus was therefore referred to the Scientific Institute of Public Health where it was identified as Alternaria infectoria, on the basis of its very small 1 or 2-celled conidia often arranged in long chains and presenting with very long secondary conidiophores. Corticotherapy was stopped and a local antifungal treatment with ketoconazole was initiated, allowing the stabilisation of the cutaneous lesions within 2 months.


Assuntos
Alternaria/classificação , Alternaria/isolamento & purificação , Dermatomicoses/microbiologia , Adulto , Idoso , Alternaria/genética , Alternaria/ultraestrutura , DNA Mitocondrial/genética , DNA Espaçador Ribossômico/análise , Dermatomicoses/diagnóstico , Dermatomicoses/patologia , Feminino , Humanos , Joelho/patologia , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , RNA Ribossômico 5,8S/genética , Análise de Sequência de DNA
19.
Ann Allergy Asthma Immunol ; 93(6): 589-93, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15609770

RESUMO

BACKGROUND: The fungus Alternaria is strongly associated with asthma, but the importance of fungal allergen products is frequently underestimated. The profile of allergen release from fungal material is poorly understood. OBJECTIVE: To investigate expression of the major allergen of Alternaria alternata, Alt a 1, during its growth in culture conditions for allergen extract production. METHODS: Allergen expression was examined by Alt a 1-specific 2-site monoclonal antibody enzyme-linked immunosorbent assay, immunoblotting, and potency assays. The release of Alt a 1 was studied by transmission electron microscopy in conjunction with immunogold staining by using antibodies with specificity for Alt a 1. RESULTS: A maximum amount of Alt a 1 was obtained after 4.5 weeks of growing, and it was found predominantly in the spent culture medium. In the same way, total IgE binding activity showed 15-fold more activity in the spent culture medium than in the buffer-extractable antigen fraction. Immunogold electron microscopy provided evidence that Alt a 1 is released from spores and mycelia. CONCLUSIONS: Alternaria alternata allergenic proteins were constantly released into the culture medium, where they accumulated. Alt a 1 was a good marker for checking optimal culture conditions for A alternata extract production intended for clinical use.


Assuntos
Alternaria/imunologia , Alternaria/ultraestrutura , Antígenos de Fungos/biossíntese , Esfingosina/biossíntese , Esporos Fúngicos/imunologia , Animais , Antígenos de Fungos/imunologia , Western Blotting , Células Cultivadas , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Imunoglobulina E/imunologia , Imuno-Histoquímica , Microscopia Eletrônica de Transmissão , Esfingosina/imunologia
20.
Int J Food Microbiol ; 81(3): 185-93, 2003 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-12485744

RESUMO

A scanning electron microscopy (SEM) study of the effect of water activity (a(w)), temperature and fungal interactions on the very early phases of Aspergillus ochraceus, Alternaria alternata and Fusarium verticillioides development on maize grains was carried out. Germination and growth of individual fungal strains were assayed at 0.92, 0.95 and 0.98 a(w), and 20 and 30 degrees C. Hyphal lengths were measured on micrographs taken by SEM at different periods of incubation. A. alternata had the highest linear growth at 0.98 a(w), and was the only species able to grow under all conditions tested, whereas A. ochraceus was not able to germinate at 0.92 a(w) at any temperature assayed. F. verticillioides demonstrated a different behaviour depending on growth temperature. Fungal interactions were studied at 0.95a(w) and 30 degrees C. A. ochraceus germination was inhibited when it was co-inoculated with one or two of the other species. A. alternata showed an increased growth rate when growing together with the other fungi, whereas growth of F. verticillioides was significantly inhibited when paired with A. ochraceus.


Assuntos
Alternaria/crescimento & desenvolvimento , Aspergillus ochraceus/crescimento & desenvolvimento , Fusarium/crescimento & desenvolvimento , Zea mays/microbiologia , Alternaria/ultraestrutura , Antibiose , Aspergillus ochraceus/ultraestrutura , Fusarium/ultraestrutura , Raios gama , Germinação , Cinética , Microscopia Eletrônica de Varredura , Esporos Fúngicos/fisiologia , Esporos Fúngicos/ultraestrutura , Temperatura , Água/metabolismo , Zea mays/efeitos da radiação
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