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1.
Int. microbiol ; 22(2): 239-246, jun. 2019. ilus, graf, tab
Artigo em Inglês | IBECS | ID: ibc-184830

RESUMO

Silver nanoparticles (SN) have been recently developed as a new class of antimicrobial agents against numerous pathogenic microorganisms. SN have also been used as efficient drug delivery systems and have been linked with increasing drug potency. Here, we demonstrated the enhanced antifungal efficacy of nystatin (NYT) and fluconazole (FLU) after conjugation with SN. The antifungal bioactivity of NYT- and FLU-coated SN was evaluated against Candida albicans ATCC 10231 and Aspergillus brasiliensis ATCC 16404 by the agar tube dilution method. The aim of this study was to determine and compare the antifungal efficacy of NYT and FLU with their SN and, finally, the combination of both nanoparticles as NYT-SN + FLU-SN against pathogenic fungi. The results indicated that all test samples showed a dose-dependent response against tested fungi. SN significantly enhanced the antifungal effects of NYT and FLU as compared to drugs alone. We observed a remarkable increase in the percent inhibition of both fungi (90-100%) when treated with a combination of both nanoparticles NYT-SN + FLU-SN at 200 μg/mL only. Furthermore, the morphological modifications occurred at the surface of fungal species were also analyzed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). While tested against primary human cell line, all SN showed negligible cytotoxicity. Hence, these results suggest that the combination of SN with NYT and FLU may have clinical implications in the treatment of fungal infections. However, in vivo studies are needed before recommending the use of these nanoparticles safely in clinical situations


No disponible


Assuntos
Antifúngicos/farmacologia , Aspergillus/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Sinergismo Farmacológico , Nanopartículas Metálicas , Prata/farmacologia , Fluconazol/farmacologia , Nistatina/farmacologia , Aspergillus/ultraestrutura , Candida albicans/ultraestrutura , Testes de Sensibilidade Microbiana , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Propriedades de Superfície/efeitos dos fármacos
2.
Int Microbiol ; 22(2): 239-246, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30810990

RESUMO

Silver nanoparticles (SN) have been recently developed as a new class of antimicrobial agents against numerous pathogenic microorganisms. SN have also been used as efficient drug delivery systems and have been linked with increasing drug potency. Here, we demonstrated the enhanced antifungal efficacy of nystatin (NYT) and fluconazole (FLU) after conjugation with SN. The antifungal bioactivity of NYT- and FLU-coated SN was evaluated against Candida albicans ATCC 10231 and Aspergillus brasiliensis ATCC 16404 by the agar tube dilution method. The aim of this study was to determine and compare the antifungal efficacy of NYT and FLU with their SN and, finally, the combination of both nanoparticles as NYT-SN + FLU-SN against pathogenic fungi. The results indicated that all test samples showed a dose-dependent response against tested fungi. SN significantly enhanced the antifungal effects of NYT and FLU as compared to drugs alone. We observed a remarkable increase in the percent inhibition of both fungi (90-100%) when treated with a combination of both nanoparticles NYT-SN + FLU-SN at 200 µg/mL only. Furthermore, the morphological modifications occurred at the surface of fungal species were also analyzed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). While tested against primary human cell line, all SN showed negligible cytotoxicity. Hence, these results suggest that the combination of SN with NYT and FLU may have clinical implications in the treatment of fungal infections. However, in vivo studies are needed before recommending the use of these nanoparticles safely in clinical situations.


Assuntos
Antifúngicos/farmacologia , Aspergillus/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Sinergismo Farmacológico , Fluconazol/farmacologia , Nanopartículas Metálicas , Nistatina/farmacologia , Prata/farmacologia , Aspergillus/ultraestrutura , Candida albicans/ultraestrutura , Testes de Sensibilidade Microbiana , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Propriedades de Superfície/efeitos dos fármacos
3.
Mycotoxin Res ; 34(2): 151-157, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29464607

RESUMO

Aflatoxins are toxic and carcinogenic secondary metabolites produced primarily by the filamentous fungi Aspergillus flavus and Aspergillus parasiticus and cause toxin contamination in food chain worldwide. Aspergillus oryzae and Aspergillus sojae are highly valued as koji molds in the traditional preparation of fermented foods, such as miso, sake, and shoyu. Koji mold species are generally perceived of as being nontoxigenic and are generally recognized as safe (GRAS). Fungal isolates were collected from a California orchard and a few were initially identified to be A. sojae using ß-tubulin gene sequences blasted against NCBI data base. These new isolates all produced aflatoxins B1, B2, G1, and G2 and were named as Pistachio Winter Experiment (PWE) strains. Thus, it is very important to further characterize these strains for food safety purposes. The full length of aflR gene of these new isolates was sequenced. Comparison of aflR DNA sequences of PWE, A. parasiticus and A. sojae, showed that the aflatoxigenic PWE strains had the six base insertion (CTCATG) similar to domesticated A. sojae, but a pre-termination codon TGA at nucleotide positions 1153-1155 was absent due to a nucleotide codon change from T to C. Colony morphology and scanning microscopic imaging of spore surfaces showed similarity of PWE strains to both A. parasiticus and A. sojae. Concordance analysis of multi locus DNA sequences indicated that PWE strains were closely linked between A. parasiticus and A. sojae. The finding documented the first report that such unique strains have been found in North America and in the world.


Assuntos
Aspergillus/genética , Aspergillus/isolamento & purificação , Proteínas de Ligação a DNA/genética , Proteínas Fúngicas/genética , Mutagênese Insercional , Fatores de Transcrição/genética , Aflatoxinas/análise , Aflatoxinas/genética , Aflatoxinas/metabolismo , Aspergillus/classificação , Aspergillus/ultraestrutura , Sequência de Bases , California , Proteínas de Ligação a DNA/química , Proteínas Fúngicas/química , Indóis/análise , Indóis/metabolismo , Tipagem de Sequências Multilocus , Fenótipo , Filogenia , Análise de Sequência de DNA , Esporos Fúngicos , Fatores de Transcrição/química
4.
Biometals ; 31(1): 45-50, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29110163

RESUMO

In this study, the removal and reduction of selenite [Se(IV)] by growing Aspergillus sp. J2 were investigated. The lag phase, growth rate and biomass of J2 was not significantly influenced by the presence of 100 mg/L Se(IV). A rapid Se(IV) removal process took place from the 3rd to the 4th day during the growth of J2. Scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction analyses showed that the Se(IV) did not cause any visible effects on cell morphology and the reduced amorphous elemental selenium [Se(0)] nanoparticles were mainly on the surface of the mycelial cell walls. The macromolecules containing amine groups also interact with Se(IV) and could play an important role in Se(IV) removal by J2.


Assuntos
Aspergillus/metabolismo , Selênio/metabolismo , Selenito de Sódio/metabolismo , Poluentes Químicos da Água/metabolismo , Aspergillus/ultraestrutura , Biodegradação Ambiental , Parede Celular/metabolismo , Parede Celular/ultraestrutura , Humanos , Micélio/metabolismo , Micélio/ultraestrutura , Nanopartículas/metabolismo , Nanopartículas/ultraestrutura , Selênio/isolamento & purificação , Selênio/toxicidade , Selenito de Sódio/isolamento & purificação , Selenito de Sódio/toxicidade , Poluentes Químicos da Água/isolamento & purificação , Poluentes Químicos da Água/toxicidade
5.
Sci Rep ; 7: 46059, 2017 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-28383064

RESUMO

A biofilter with fungus was developed for efficient degradation of benzene, which can overcome the potential risk of leakage commonly found in such services. Results indicated that the optimum parameter values were temperature 40 °C, pH 6, and 500 mg L-1 of the initial benzene concentration. Besides, the empty bed residence time and inlet load range of biofilter were set to 20 s and 21.23-169.84 g m-3 h-1 respectively. Under these conditions, this biofilter can obtain the maximum removal efficiency of more than 90%, the eliminating capacity could be up to 151.67 g m-3 h-1. Furthermore, scanning electron microscopy was used to investigate three filler materials for packing fungus biofilm. This is the first study introducing an Aspergillus strain for benzene removal and these results highlight that the development of this biofilter has the potential scaling-up application as gas-processing of industrial wastes.


Assuntos
Aspergillus/fisiologia , Benzeno/metabolismo , Filtração/instrumentação , Aspergillus/ultraestrutura , Benzeno/isolamento & purificação , Biodegradação Ambiental , Biofilmes , Biomassa , Concentração de Íons de Hidrogênio , Projetos Piloto , Temperatura Ambiente , Fatores de Tempo
6.
BMC Genomics ; 17: 428, 2016 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-27267057

RESUMO

BACKGROUND: Aspergillus cristatus is the dominant fungus involved in the fermentation of Chinese Fuzhuan brick tea. Aspergillus cristatus is a homothallic fungus that undergoes a sexual stage without asexual conidiation when cultured in hypotonic medium. The asexual stage is induced by a high salt concentration, which completely inhibits sexual development. The taxon is therefore appropriate for investigating the mechanisms of asexual and sexual reproduction in fungi. In this study, de novo genome sequencing and analysis of transcriptomes during culture under high- and low-osmolarity conditions were performed. These analyses facilitated investigation of the evolution of mating-type genes, which determine the mode of sexual reproduction, in A. cristatus, the response of the high-osmolarity glycerol (HOG) pathway to osmotic stimulation, and the detection of mycotoxins and evaluation of the relationship with the location of the encoding genes. RESULTS: The A. cristatus genome comprised 27.9 Mb and included 68 scaffolds, from which 10,136 protein-coding gene models were predicted. A phylogenetic analysis suggested a considerable phylogenetic distance between A. cristatus and A. nidulans. Comparison of the mating-type gene loci among Aspergillus species indicated that the mode in A. cristatus differs from those in other Aspergillus species. The components of the HOG pathway were conserved in the genome of A. cristatus. Differential gene expression analysis in A. cristatus using RNA-Seq demonstrated that the expression of most genes in the HOG pathway was unaffected by osmotic pressure. No gene clusters associated with the production of carcinogens were detected. CONCLUSIONS: A model of the mating-type locus in A. cristatus is reported for the first time. Aspergillus cristatus has evolved various mechanisms to cope with high osmotic stress. As a fungus associated with Fuzhuan tea, it is considered to be safe under low- and high-osmolarity conditions.


Assuntos
Aspergillus/genética , Genoma Fúngico , Genômica , Chá/microbiologia , Transcriptoma , Aspergillus/classificação , Aspergillus/metabolismo , Aspergillus/ultraestrutura , Evolução Biológica , Biologia Computacional/métodos , Fermentação , Proteínas Fúngicas/genética , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Sistema de Sinalização das MAP Quinases , Anotação de Sequência Molecular , Família Multigênica , Filogenia , Locos de Características Quantitativas , Chá/metabolismo
8.
Clin Infect Dis ; 61(11): 1664-70, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26240202

RESUMO

BACKGROUND: Data on the accuracy of conventional histomorphologic diagnosis are limited, especially in mucormycosis. We therefore investigated the accuracy of histomorphologic diagnosis of mucormycosis and aspergillosis, using immunohistochemistry (IHC) tests for mucormycosis and aspergillosis. METHODS: Patients enrolled met the modified criteria for proven and probable mucormycosis (during a 22-year period) or invasive aspergillosis (during a 6-year period) and had formalin-fixed, paraffin-embedded tissues available. We first tested the diagnostic performance of IHC for mucormycosis and aspergillosis in proven cases. Then we determined the accuracy of histomorphologic diagnosis of probable cases, using the IHC tests. RESULTS: In 7 proven cases of mucormycosis, the sensitivity and specificity of mucormycosis IHC were 100% (95% confidence interval, 65%-100%) and 100% (68%-100%), respectively. In 8 proven cases of aspergillosis, and the sensitivity and specificity of aspergillosis IHC staining were 87% (53%-98%) and 100% (65%-100%), respectively. Of 23 probable mucormycosis cases, 20 (87%) were positive with mucormycosis IHC, 2 (9%) were positive with aspergillosis IHC (including 1 positive for both), and 2 were negative with both. Of 16 probable aspergillosis cases, 10 (63%) were positive with aspergillosis IHC, 4 (25%) were positive with mucormycosis IHC, and 2 (13%) were negative with both tests. CONCLUSIONS: Aspergillosis and mucormycosis seem not to be correctly diagnosed morphologically, because some of the probable cases showed either test with both antibodies or failure to stain with the homologous antibody. In the absence of fungal culture results, the IHC tests seem helpful in differentiating between aspergillosis and mucormycosis.


Assuntos
Confiabilidade dos Dados , Imuno-Histoquímica/métodos , Aspergilose Pulmonar Invasiva/diagnóstico , Mucormicose/diagnóstico , Adulto , Aspergillus/ultraestrutura , Feminino , Humanos , Aspergilose Pulmonar Invasiva/microbiologia , Masculino , Pessoa de Meia-Idade , Mucormicose/microbiologia , Micologia/métodos , Reação em Cadeia da Polimerase , Rhizopus/ultraestrutura , Sensibilidade e Especificidade , Adulto Jovem
9.
Appl Environ Microbiol ; 81(17): 5794-803, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-26092450

RESUMO

Submicronic fungal fragments have been observed in in vitro aerosolization experiments. The occurrence of these particles has therefore been suggested to contribute to respiratory health problems observed in mold-contaminated indoor environments. However, the role of submicronic fragments in exacerbating adverse health effects has remained unclear due to limitations associated with detection methods. In the present study, we report the development of an indirect immunodetection assay that utilizes chicken polyclonal antibodies developed against spores from Aspergillus versicolor and high-resolution field emission scanning electron microscopy (FESEM). Immunolabeling was performed with A. versicolor fragments immobilized and fixed onto poly-l-lysine-coated polycarbonate filters. Ninety percent of submicronic fragments and 1- to 2-µm fragments, compared to 100% of >2-µm fragments generated from pure freeze-dried mycelial fragments of A. versicolor, were positively labeled. In proof-of-concept experiments, air samples collected from moldy indoor environments were evaluated using the immunolabeling technique. Our results indicated that 13% of the total collected particles were derived from fungi. This fraction comprises 79% of the fragments that were detected by immunolabeling and 21% of the spore particles that were morphologically identified. The methods reported in this study enable the enumeration of fungal particles, including submicronic fragments, in a complex heterogeneous environmental sample.


Assuntos
Aspergillus/isolamento & purificação , Imunoensaio/métodos , Microscopia Eletrônica de Varredura/métodos , Esporos Fúngicos/isolamento & purificação , Aspergillus/química , Aspergillus/crescimento & desenvolvimento , Aspergillus/ultraestrutura , Tamanho da Partícula , Esporos Fúngicos/química , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/ultraestrutura
11.
Appl Biochem Biotechnol ; 175(3): 1588-602, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25413792

RESUMO

The production of extracts containing a pool of enzymes for extensive biomass deconstruction can lead to significant advantages in biorefinery applications. In this work, a strain of Aspergillus awamori IOC-3914 was used for the simultaneous production of five groups of hydrolases by solid-state fermentation of babassu cake. Sequential experimental design strategies and multivariate optimization using the desirability function were first used to study temperature, moisture content, and granulometry. After that, further improvements in product yields were achieved by supplementation with other agro-industrial materials. At the end of the study, the production of enzymes was up to 3.3-fold increased, and brewer's spent grains and babassu flour showed to be the best supplements. Maximum activities for endoamylases, exoamylases, cellulases (CMCases), xylanases, and proteases achieved were 197, 106, 20, 835, and 57 U g(-1), respectively. The strain was also able to produce ß-glucosidases and debranching amylases (up to 35 and 43 U g(-1), respectively), indicating the potential of its enzyme pool for cellulose and starch degradation.


Assuntos
Amilases/biossíntese , Aspergillus/enzimologia , Biotecnologia/métodos , Celulases/biossíntese , Endo-1,4-beta-Xilanases/biossíntese , Fermentação , Peptídeo Hidrolases/biossíntese , Aspergillus/crescimento & desenvolvimento , Aspergillus/ultraestrutura , Análise Multivariada
12.
Fungal Genet Biol ; 73: 61-8, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25312859

RESUMO

Fungal pathogens need regulated mechanical and morphological fine-tuning for pushing through substrates to meet their metabolic and functional needs. Currently very little is understood on how coordinated colony level morphomechanical modifications regulate their behavior. This is due to an absence of a method that can simultaneously map, quantify, and correlate global fluctuations in physical properties of the expanding fungal colonies. Here, we show that three-dimensional ultrasonic reflections upon decoding can render acoustic contrast tomographs that contain information on material property and morphology in the same time scale of one important phytopathogen, Aspergillus parasiticus, at multiple length scales. By quantitative analysis of the changes in acoustic signatures collected as the A. parasiticus colony expands with time, we further demonstrate that the pathogen displays unique acoustic signatures during synthesis and release of its hepatocarcinogenic secondary metabolite, aflatoxin, suggesting an involvement of a multiscale morphomechanical reorganization of the colony in this process. Our studies illustrate for the first time, the feasibility of generating in any invading cell population, four-dimensional maps of global physical properties, with minimal physical perturbation of the specimens. Our developed method that we term quantitative acoustic contrast tomography (Q-ACT), provides a novel diagnostic framework for the identification of in-cell molecular factors and discovery of small molecules that may modulate pathogen invasion in a host.


Assuntos
Aflatoxinas/biossíntese , Aspergillus/fisiologia , Ultrassonografia/métodos , Aspergillus/ultraestrutura , Metabolismo Secundário/fisiologia
13.
Bioresour Technol ; 171: 217-26, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25203229

RESUMO

The present study is targeted towards development of a three member fungal consortium for effective removal of metals [Cr(6+) and Cu(2+)] and dyes [AB and PO] from mixed waste streams. Initial studies using individual fungal strain showed that Aspergillus lentulus was best for Cu(2+) and AB removal, Aspergillus terreus for Cr(6+) removal whereas, Rhizopus oryzae was best for PO removal. Based on the complementary pollutant affinities and positive interactions, a consortium comprising all three strains was developed. Consortium removed 100% Cr(6+) and 81.60% Cu(2+) from metal mixture which was significantly higher than that achieved individually by A. lentulus (Cr(6+): 83.11%; Cu(2+): 67.32%), A. terreus (Cr(6+): 95.57%; Cu(2+): 65.77%) or R. oryzae (Cr(6+): 25.34%; Cu(2+): 30.20%). Further, 98.0% AB and 100.0% PO was removed after 48 h by the consortia. Unlike individual strains, consortium's performance was unaltered irrespective of the complexity of metal-dye mixtures, thereby establishing its superiority.


Assuntos
Aspergillus/metabolismo , Corantes/metabolismo , Metais Pesados/metabolismo , Rhizopus/metabolismo , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Poluentes Químicos da Água/metabolismo , Aspergillus/ultraestrutura , Biodegradação Ambiental , Corantes/análise , Cinética , Metais Pesados/análise , Microscopia Eletrônica de Varredura , Modelos Biológicos , Rhizopus/ultraestrutura , Especificidade da Espécie , Espectrofotometria , Espectrofotometria Atômica , Fatores de Tempo , Poluentes Químicos da Água/análise
14.
Mycotoxin Res ; 29(4): 261-9, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23780853

RESUMO

The ethyl acetate extract of leaves, seeds and flowers of Heracleum persicum, a medicinal plant of Iran (family Apiaceae) inhibited growth and aflatoxin (AF) production of Aspergillus parasiticus. On the basis of total dry weight growth inhibition by the leaf extract ranged from 17.1 to 36.9 %, by the flower extract from 32.2 to 75.6 %, and by the seed extract from 27.5 to 74.9 %. Production of AFB1 and AFG1 was inhibited in a dose-dependent manner, with a reduction of 88.5-100 % at the highest concentration of 8,000 µg/ml tested. The flower extract decreased ergosterol content of hyphae most significantly. Electron microscopy further revealed structural defects in the treated A. parasiticus including disruption of cytoplasmic membranous compartments, detachment of plasma membrane from the cell wall, and disorganization of hyphal compartments. Collapsed hyphae without conidiation, shorter branches and undifferentiated hyphal tips were also evident. The results indicate that H. persicum extract exerts antifungal and anti-AF activities by disrupting plasma membrane integrity and permeability mainly through interference with ergosterol biosynthesis. These results show that H. persicum can serve as a potent and safe alternative for inhibiting toxigenic aspergilli growth and thus preventing AF contamination of foods and feeds.


Assuntos
Aflatoxinas/biossíntese , Aspergillus/crescimento & desenvolvimento , Heracleum/metabolismo , Extratos Vegetais/farmacologia , Aflatoxinas/análise , Aspergillus/metabolismo , Aspergillus/ultraestrutura , Ergosterol/análise , Ergosterol/metabolismo , Hifas/crescimento & desenvolvimento , Hifas/metabolismo , Hifas/ultraestrutura , Irã (Geográfico) , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão
15.
Molecules ; 18(2): 1660-71, 2013 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-23358324

RESUMO

Polygalacturonases (PG) are pectinolytic enzymes that have technological, functional and biological applications in food processing, fruit ripening and plant-fungus interactions, respectively. In the present, a microtitre plate methodology was used for rapid screening of 61 isolates of fungi from Aspergillus section Nigri to assess production of endo- and exo-PG. Studies of scale-up were carried out in a fixed bed reactor operated under different parameters using the best producer strain immobilised in orange peels. Four experiments were conducted under the following conditions: the immobilised cells without aeration; immobilised cells with aeration; immobilised cells with aeration and added pectin; and free cells with aeration. The fermentation was performed for 168 h with removal of sample every 24 h. Aspergillus niger strain URM 5162 showed the highest PG production. The results obtained indicated that the maximum endo- and exo-PG activities (1.18 U · mL-1 and 4.11 U · mL-1, respectively) were obtained when the reactor was operating without aeration. The microtitre plate method is a simple way to screen fungal isolates for PG activity detection. The fixed bed reactor with orange peel support and using A. niger URM 5162 is a promising process for PG production at the industrial level.


Assuntos
Aspergillus/enzimologia , Reatores Biológicos/microbiologia , Poligalacturonase/biossíntese , Aspergillus/citologia , Aspergillus/crescimento & desenvolvimento , Aspergillus/ultraestrutura , Biomassa , Citrus sinensis , Ensaios Enzimáticos , Fermentação
16.
Annu Rev Food Sci Technol ; 4: 293-311, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23244396

RESUMO

Aflatoxins are among the principal mycotoxins that contaminate economically important food and feed crops. Aflatoxin B1 is the most potent naturally occurring carcinogen known and is also an immunosuppressant. Occurrence of aflatoxins in crops has vast economic and human health impacts worldwide. Thus, the study of aflatoxin biosynthesis has become a focal point in attempts to reduce human exposure to aflatoxins. This review highlights recent advances in the field of aflatoxin biosynthesis and explores the functional connection between aflatoxin biosynthesis, endomembrane trafficking, and response to oxidative stress. Dissection of the regulatory mechanisms involves a complete comprehension of the aflatoxin biosynthetic process and the dynamic network of transcription factors that orchestrates coordinated expression of the target genes. Despite advancements in the field, development of a safe and effective multifaceted approach to solve the aflatoxin food contamination problem is still required.


Assuntos
Aflatoxinas/biossíntese , Contaminação de Alimentos/prevenção & controle , Aflatoxina B1/análise , Aflatoxina B1/biossíntese , Aflatoxinas/análise , Aspergillus/enzimologia , Aspergillus/metabolismo , Aspergillus/ultraestrutura , Carcinógenos , Produtos Agrícolas/química , Contaminação de Alimentos/análise , Humanos , Estresse Oxidativo , Plantas Geneticamente Modificadas/microbiologia , Fatores de Transcrição/fisiologia
18.
J Biomed Biotechnol ; 2012: 196264, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23118499

RESUMO

Ability of two strains of Aspergillus terreus (ATCC 74135 and ATCC 20542) for production of lovastatin in solid state fermentation (SSF) using rice straw (RS) and oil palm frond (OPF) was investigated. Results showed that RS is a better substrate for production of lovastatin in SSF. Maximum production of lovastatin has been obtained using A. terreus ATCC 74135 and RS as substrate without additional nitrogen source (157.07 mg/kg dry matter (DM)). Although additional nitrogen source has no benefit effect on enhancing the lovastatin production using RS substrate, it improved the lovastatin production using OPF with maximum production of 70.17 and 63.76 mg/kg DM for A. terreus ATCC 20542 and A. terreus ATCC 74135, respectively (soybean meal as nitrogen source). Incubation temperature, moisture content, and particle size had shown significant effect on lovastatin production (P < 0.01) and inoculums size and pH had no significant effect on lovastatin production (P > 0.05). Results also have shown that pH 6, 25°C incubation temperature, 1.4 to 2 mm particle size, 50% initial moisture content, and 8 days fermentation time are the best conditions for lovastatin production in SSF. Maximum production of lovastatin using optimized condition was 175.85 and 260.85 mg/kg DM for A. terreus ATCC 20542 and ATCC 74135, respectively, using RS as substrate.


Assuntos
Aspergillus/metabolismo , Biomassa , Biotecnologia/métodos , Fermentação , Lovastatina/biossíntese , Oryza/metabolismo , Óleos Vegetais/metabolismo , Agricultura , Aspergillus/efeitos dos fármacos , Aspergillus/crescimento & desenvolvimento , Aspergillus/ultraestrutura , Vias Biossintéticas/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Fermentação/efeitos dos fármacos , Umidade , Concentração de Íons de Hidrogênio/efeitos dos fármacos , Lignina/metabolismo , Lovastatina/análise , Lovastatina/química , Minerais/farmacologia , Nitrogênio/farmacologia , Oryza/efeitos dos fármacos , Óleo de Palmeira , Tamanho da Partícula , Soluções , Especificidade por Substrato/efeitos dos fármacos , Temperatura Ambiente , Fatores de Tempo
19.
World J Microbiol Biotechnol ; 28(7): 2521-30, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22806158

RESUMO

The isolate Aspergillus versicolor was obtained from an estuary, which is exposed to metal contamination. It was found to have a good metal tolerance and sorption capacity. Further studies revealed that the rate of metal removal from solution is very rapid in the first 5-10 min, and is favoured by a pH of 6.0. The biosorption data obtained was explained by the Freundlich adsorption isotherm model and followed a pseudo-second order kinetics reaction. The fungus showed a higher accumulation of fatty acids when grown in presence of metals as compared to the mycelium grown in absence of the metal; there was also an increase in the saturation index of fatty acids in presence of Cu(2+) which serves as a protective mechanism for the fungus. Fourier Transform Infrared, scanning electron microscopy and EDAX analysis indicated that metal removal from solution by A. versicolor occurred by a passive adsorption to the fungal cell surface, involving an ion exchange mechanism.


Assuntos
Aspergillus/metabolismo , Metais/metabolismo , Aspergillus/ultraestrutura , Cobre/metabolismo , Ácidos Graxos/metabolismo , Cinética , Chumbo/metabolismo , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier
20.
Rev Esp Quimioter ; 25(1): 47-55, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22488542

RESUMO

OBJECTIVES: the aims of the study were to explore the activity of total and free (according to protein binding) maximal concentrations achieved in serum after multiple doses of voriconazole 400/200 mg and anidulafungin 200/100 mg against Aspergillus fumigatus and Aspergillus flavus and the human albumin or serum effects on antifungal activity. MATERIAL AND METHODS: Time-kill curves were performed with two A. fumigatus and two A. flavus strains at voriconazole and anidulafungin Cmax concentrations using different media: a) RPMI broth (Cmax-RPMI); b) RPMI with human serum (Cmax-HS), and c) RPMI with human albumin (Cmax-HAlb). In parallel, free-drug (fCmax) concentrations considering theoretical protein binding were performed in RPMI broth. Aspergillus metabolic activity was measured by the XTT reduction assay. RESULTS: Voriconazol or voriconazole plus anidulafungin reduced >88.4% the metabolic activity of Aspergillus sp. at Cmax-RPMI and fCmax after 48 h of exposition. Anidulafungin alone showed poor metabolic reductions (<80.1% at Cmax- RPMI and <15% at fCmax). Anidulafungin activity, but not voriconazole activity alone or combined decreased in presence of HS or HAlb (more pronounced in A. flavus strains and HAlb). However, anidulafungin Cmax-HS or Cmax-HAlb against A. fumigatus strains were significantly more active (p<0.05) than fCmax in RPMI. These species and culture medium-dependent impact of human protein binding in the activity of anidulafungin was related to macroscopic and microscopic differences among mycelial mat grown in RPMI, HS or HAlb in whose XTT retention was different. CONCLUSIONS: Synergism could not be demonstrated due to the high activity showed by voriconazole. Protein binding has not impact on voriconazole activity and this impact is considerably less than predicted by free concentration extrapolated from theoretical binding rate on anidulafungin. The XTT colorimetric assay needs to be standardized for use with Aspergillus spp. since without DMSO extraction the activity of echinocandins in a free-human protein RPMI medium could be overestimated.


Assuntos
Antifúngicos/metabolismo , Antifúngicos/farmacologia , Aspergillus/efeitos dos fármacos , Equinocandinas/farmacologia , Pirimidinas/metabolismo , Pirimidinas/farmacologia , Triazóis/metabolismo , Triazóis/farmacologia , Anidulafungina , Aspergillus/ultraestrutura , Aspergillus flavus/efeitos dos fármacos , Aspergillus flavus/ultraestrutura , Aspergillus fumigatus/efeitos dos fármacos , Aspergillus fumigatus/ultraestrutura , Colorimetria , Meios de Cultura , Combinação de Medicamentos , Humanos , Testes de Sensibilidade Microbiana , Ligação Proteica , Albumina Sérica/química , Sais de Tetrazólio , Fatores de Tempo , Voriconazol
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