ABSTRACT
La búsqueda de fuentes naturales para controlar los microorganismos es de interés en la producción de alimentos. Este estudio evaluó la composición química y la actividad antimicrobiana del aceite esencial de las hojas de Psidium cattleianum. El aceite esencial se extrajo por hidrodestilación y se identificó por GC-MS. La clase predominante de compuestos fueron los sesquiterpenos (47,6%) y los principales fueron trans-ß-cariofileno (14,7%), 1,8-cineol (11,7%) y É£-muuroleno (5,6%). Actividad antimicrobiana se realizó mediante la técnica de microdilución contra ocho hongos y ocho bacterias. Concentración inhibitoria mínima varió de 0,17 a 11,25 mg mL-1 para hongos y de 1,40 a 16,87 mg mL-1 para bacterias. Principales actividades fueron contra hongos Aspergillus fumigatus (ATCC 1022), Aspergillus ochraceus (ATCC 12066), Aspergillus versicolor (ATCC 11730) y Trichoderma viride (IAM 5061), y bacterias Pseudomonas aeruginosa (ATCC 27853), Bacillus cereus (clinical isolate) y Staphylococcus aureus (ATCC 6538) con potencial para prevenir enfermedades transmitidas por alimentos.
The search for natural sources to control microorganisms is of interest in food production. This study evaluated the chemical composition and antimicrobial activity of the essential oil from Psidium cattleianum leaves. The essential oil was extracted by hydrodistillation, and identified by GC-MS. The predominant class of compounds was sesquiterpenes (47.6%) and the major compounds were trans-ß-caryophyllene (14.7%), 1,8-cineole (11.7%) and É£-muurolene (5.6%). The antimicrobial activity was carried out by microdillution technique against eight fungi and eight bacteria. The minimum inhibitory concentration ranged from 0.17 to 11.25 mg mL-1 for fungi, and from 1.40 to 16.87 mg mL-1 for bacteria. The highest activities were against fungi Aspergillus fumigatus (ATCC 1022), Aspergillus ochraceus (ATCC 12066), Aspergillus versicolor (ATCC 11730), and Trichoderma viride (IAM 5061), and bacteria Pseudomonas aeruginosa (ATCC 27853), Bacillus cereus (clinical isolate), and Staphylococcus aureus (ATCC 6538) with potential to prevent foodborne diseases.
Subject(s)
Psidium/chemistry , Anti-Infective Agents , Aspergillus , Aspergillus fumigatus , Trichoderma , Aspergillus ochraceus , Plant ExtractsABSTRACT
Este trabalho avaliou o efeito antifúngico in vitro de toxina killer de Hansenula wingei contra Aspergillus ochraceus e Penicillium expansum deteriorantes de alimentos. O extrato livre de células-ELC contendo a toxina killer (obtido a partir do cultivo da levedura em Caldo MPL a 25ºC/96 horas) foi submetido ao ensaio antifúngico por meio de análise microscópica, determinando-se a porcentagem de germinação conidial e o desenvolvimento de hifas dos fungos testados. H. wingei inibiu a germinação conidial de A. ochraceus e P. expansum em 98,91% e 96,49%, respectivamente, bem como a inibição do desenvolvimento micelial de ambos os fungos foi maior que 78%. O composto antifúngico mostrou-se estável ao tratamento térmico de 90ºC/30 min., indicando a possibilidade de aplicação no biocontrole in situ de frutos pós-colheita.
Subject(s)
Antifungal Agents/administration & dosage , Aspergillus ochraceus/pathogenicity , Fruit , Fungi , Yeasts , Penicillium/pathogenicity , PichiaABSTRACT
Background: Aspergillus ochraceus was isolated from coffee pulp and selected as an interesting hydroxycinnamoyl esterase strain producer, using an activity microplate high-throughput screening method. In this work, we purified and characterized a new type C A. ochraceus feruloyl esterase (AocFaeC), which synthesized specifically butyl hydroxycinnamates in a ternary solvent system. Results: AocFaeC was produced by solid state fermentation, reaching its maximal activity (1.1 U/g) after 48 h of culture. After purification, the monomeric protein (34 kDa) showed a specific activity of 57.9 U/mg towards methyl ferulate. AocFaeC biochemical characterization confirmed its identity as a type C feruloyl esterase and suggested the presence of a catalytic serine in the active site. Its maximum hydrolytic activity was achieved at 40°C and pH 6.5 and increased by 109 and 77% with Ca2+ and Mg2+, but decreased by 90 and 45% with Hg2+ and Cu2+, respectively. The initial butyl ferulate synthesis rate increased from 0.8 to 23.7 nmol/min after transesterification condition improvement, using an isooctane:butanol:water ternary solvent system, surprisingly the synthesis activity using other alcohols was negligible. At these conditions, the synthesis specific activities for butyl p-coumarate, sinapinate, ferulate, and caffeate were 87.3, 97.6, 168.2, and 234 U/µmol, respectively. Remarkably, AocFaeC showed 5 folds higher butyl caffeate synthesis rate compared to type B Aspergillus niger feruloyl esterase, a well-known enzyme for its elevated activity towards caffeic acid esters. Conclusions: Type C feruloyl esterase from A. ochraceus is a butanol specific biocatalyst for the synthesis of hydroxycinnamates in a ternary solvent system
Subject(s)
Aspergillus ochraceus/enzymology , Carboxylic Ester Hydrolases/metabolism , Coumaric Acids/chemical synthesis , Solvents , Spectrophotometry , Carboxylic Ester Hydrolases/isolation & purification , Chromatography , Coffee , Butanols , Electrophoresis , FermentationABSTRACT
Antecedentes: El kéfir de agua (KA) es una bebida producida con soluciones azucaradas fermentadas con gránulos constituidos por bacterias ácido lácticas (BAL) y levaduras embebidas en una matriz de polisacárido. Aspergillus ochraceus es un hongo filamentoso micotoxigénico, contaminante frecuente y productor de ocratoxina en café, uvas y vino. Se ha estudiado la actividad antifúngica de productos fermentados por BAL pero hasta ahora no se conocen estudios sobre la capacidad antifúngica del KA. Objetivos: Evaluar la capacidad antifúngica de soluciones de panela fermentadas a diferentes tiempos y temperaturas con KA sobre A. ochraceus. Métodos: Se inocularon 10 µL de una suspensión (3x107 conidios. ml-1) de A. ochraceus en agar malta mezclado con sobrenadantes libres de células (SLC) de los productos fermentados, incubando a 25°C y midiendo diariamente el diámetro del micelio, con lo cual se determinó el efecto antifúngico sobre la tasa de crecimiento y la fase de latencia. Se determinó la concentración de ácidos orgánicos (AO) en los SLC mediante HPLC. Resultados: Los productos fermentados por mayor tiempo y temperatura tuvieron mayor concentración de (AO) y mayor descenso de pH siendo el SLC8 (pH: 2,8) el más inhibitorio. Conclusiones: La solución de panela en agua fue adecuada para fermentación con gránulos de KA, obteniéndose metabolitos con propiedades antifúngicas como los AO.
Subject(s)
Humans , Kefir , Aspergillus ochraceus , Water , Organic Acids , Antifungal AgentsABSTRACT
Background: Tannases are enzymes that may be used in different industrial sectors as, for example, food and pharmaceutical. They are obtained mainly from microorganisms, as filamentous fungi. However, the diversity of fungi stays poorly explored for tannase production. In this article, Aspergillus ochraceus is presented as a new source of tannase with interesting features for biotechnological applications. Results: Extracellular tannase production was induced when the fungus was cultured in Khanna medium with tannic acid as carbon source. The extracellular tannase was purified 9-fold with 2 percent recovery and a single band corresponding to 85 kDa was observed in SDS-PAGE. The native apparent molecular mass was estimated as 112 kDa. Optima of temperature and pH were 40ºC and 5.0, respectively. The enzyme was fully stable from 40ºC to 60ºC during 1 hr. The activity was enhanced by Mn2+ (33-39 percent) and NH4+ (15 percent). The purified tannase hydrolyzed tannic acid and methyl gallate with Km of 0.76 mM and 0.72 mM, respectively, and Vmax of 0.92 U/mg protein and 0.68 U/mg protein, respectively. The analysis of a partial sequence of the tannase encoding gene showed an open read frame of 567 bp and a sequence of 199 amino acids were predicted. TLC analysis revealed the presence of gallic acid as a tannic acid hydrolysis product. Conclusion: The extracellular tannase produced by A. ochraceus showed distinctive characteristics such as monomeric structure and activation by Mn2+, suggesting a new kind of fungal tannases with biotechnological potential. Further, it was the first time that a partial gene sequence for A. ochraceus tannase was described.
Subject(s)
Aspergillus ochraceus/enzymology , Carboxylic Ester Hydrolases/genetics , Carboxylic Ester Hydrolases/metabolism , Electrophoresis , Fermentation , Hydrogen-Ion Concentration , Hydrolyzable Tannins , Polymerase Chain Reaction , TemperatureABSTRACT
To find out natural antimicrobial agents as alternative in therapeutics and to preserve food, the methanol extract of Solanum palinacanthum aerial parts was submitted to purification steps guided by antibacterial and antifungal assays. As a consequence, the flavonoid rutin and 3,5-dicaffeoylquinic acid were isolated by column chromatographyand high performance liquid chromatography, and identified by mass and nuclear magnetic resonance spectrometry. Minimal inhibitory concentrations (MIC) of the quinic acid derivative against Aeromonas hydrophila, Bacillus subtilis, Staphylococcus aureus and the fungus Aspergillus ochraceus were 250, 1000, 1000 and > 568µg/mL, respectively. Against the same microorganisms, MIC for rutin were 1000, > 1000, > 1000 and 35µg/mL, respectively. Rutinwas very promising for A. ochraceus control, since its MIC against such fungus was close to the one observed for benzalkonium chloride, which is used as a fungicide in Brazil.
Com vistas a descobrir antimicrobianos de origem natural para uso terapêutico ou para a preservação de alimentos, o extrato metanólico das partes aéreas de Solanum palinacanthum foi submetido a fracionamentos direcionados por testes para avaliar a atividade antibacteriana e antifúngica. Em decorrência, o flavonóide rutina e o ácido 3,5-dicafeoilquínico foram isolados por cromatografia em coluna e por cromatografia líquida de alta eficiência, para serem identificados por espectrometria de massas e de ressonância magnética nuclear. As concentrações inibitórias mínimas (CIM) do derivado do ácido cafeico contra Aeromonas hydrophila, Bacillus subtilis, Staphylococcus aureus e o fungo Aspergillus ochraceus foram 250, 1000, 1000 e > 568µg/mL, respectivamente. Contra os mesmos organismos, os valores de CIM para a rutina foram 1000, > 1000, > 1000 e 35µg/mL, respectivamente. A rutina mostrou-se muito promissora para o controle de A. ochraceus, pois seu valor de CIM contra tal fungo foi bem próximo ao observado para o cloreto de benzalcônio, que é empregado como fungicida no Brasil.
Subject(s)
Anti-Bacterial Agents/isolation & purification , Antifungal Agents/isolation & purification , Solanum/chemistry , Anti-Bacterial Agents/pharmacology , Antifungal Agents/pharmacology , Aspergillus ochraceus/drug effects , Chromatography , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Magnetic Resonance Spectroscopy , Mass Spectrometry , Microbial Sensitivity Tests , Plant Extracts/pharmacologyABSTRACT
In our continuing study on the chemical constituents in the fruiting bodies of Daldinia concentrica, diaporthin and orthosporin were isolated. Their chemical structures were assigned based on various spectral studies. Diaporthin and orthosporin, phytotoxins previously found in Aspergillus ochraceus, were isolated from wood-rotting mushroom D. concentrica for the first time.
Subject(s)
Agaricales , Aspergillus ochraceus , FruitABSTRACT
Esporos de A. ochraceus, A. carbonarius e A. niger foram inoculados em três meios de cultura: Agar extrato de levedura Czapeck (CYA), Agar Glicerol 18per center com dicloran (DG18), Agar Extrato de levedura e malte com 40 per center de glicose (MY40G). As placas foram incubadas em 5 temperaturas diferentes: 8, 25, 30, 35 e 41ºC. O crescimento dos fungos foi avaliado medindo o diâmetro da colônia a cada 24h. O objetivo deste trabalho foi determinar a influência de três meios de cultura com atividade de água diferente tempo de incubação e temperaturas, sobre o crescimento de A. ochraceus, A. carbonarius and A. niger. Nenhuma das espécies cresceu à 8ºC em nenhum dos meios de cultura. Para A. carbonarius, 30ºC foi a melhor temperatura para o seu crescimento enquanto para A. niger temperaturas acima de 30ºC foram melhores em todos os meios de cultura. A. ochraceus apresentou bom crescimento a 25 e 30ºC em todos os meios de cultura, enquanto seu crescimento à 35ºC foi mais lento, especialmente no meio CYA. A 41ºC, A. ochraceus não cresceu em nenhum dos meios de cultura estudados e A. carbonarius foi significantemente inibido. A. niger cresceu à temperatura de 41ºC e apresentou-se como o fungo mais xerofílico, comparado com A. carbonarius e A. ochraceus.
Subject(s)
Aspergillus , Aspergillus niger , Aspergillus ochraceus , In Vitro Techniques , Culture Media , Growth , Weights and MeasuresABSTRACT
O objetivo desta revisão residiu em compilar dados sobre a microbiota dos grãos de café, visando correlacioná-la com procedimentos que permitam minimizar a contaminação microbiológica. Foram abordados o cultivo e o processamento dos grãos de café, os microorganismos a eles associados nas fases de pré e pós-colheita, bem como a contaminação por fungos especificamente o Aspergillus ochraceus (produtos de ocratoxina). Concluiu-se que para manter a sanidade da bebida, a longo prazo, devem ser adotadas boas práticas de produção, porém em curto prazo é necessário buscar alimentos que inibam ou impeçam o desenvolvimento da toxina em grãos armazenados.
Subject(s)
Crop Production , Aspergillus ochraceus , Biological Contamination , Coffee , Food Handling , Food Technology , Mycotoxins , Ochratoxins , Food MicrobiologyABSTRACT
Effect of 6-MFA (sixth mycelial fraction of acetone), an interferon inducer obtained from fungus A. ochraceus on hepatic mixed function oxidase system (MFO) of rat has been investigated. Treatment with 6-MFA, 100 mg/kg/day, ip for 1-5 days to adult rats inhibited significantly the different indices of MFO system, viz. hepatic cytochrome P-450, cytochrome b5 content, cytochrome c reductase, aminopyrine-N-demethylase and acetanilide hydroxylase activities. Similar treatment for 3 days in young growing rats significantly inhibited MFO system's components except acetanilide hydroxylase activity which showed marked elevation. These effects seem to be specific as in vitro experiments suggested that 6-MFA does not compete with subsdtrates nor it acts as a sponge reacting with the end product to give false inhibitory effect. It is concluded from the present study that 6-MFA like other interferon inducers depresses MFO system in rats. Its possible clinical implications are discussed.
Subject(s)
Animals , Aspergillus ochraceus , Enzyme Inhibitors/toxicity , Fungal Proteins/isolation & purification , Interferon Inducers/isolation & purification , Male , Microsomes, Liver/drug effects , Mixed Function Oxygenases/antagonists & inhibitors , RatsABSTRACT
Ochratoxin A [OA] is a toxic metabolite produced by Aspergillus ochraceus. OA is a potent agent causing kidney and liver damage, carcinogen, mutagen, immunosuppressive and teratogen. L-Cysteine [Cys] plays and important role in natural detoxification mechanisms by several ways inside the body; beside its effect and the related compounds [-SH group] could inhibit the toxin production by such fungi in vitro studies. In the present work, we studied the possible protective role of Cys against OA in rats. In a 7 days experiment, intraperitoneal [I.P] injection of Cys [300 mg/kg.b.wt.] has proven useful against OA toxicity [1/2] LD50] in rats. In more prolonged experiment, Cys, OA, or Cys prior OA with 15 min. [Cys+OA] were I.P injected for 30 successive days. Clinical symptoms, mortality rate, post mortum findings, weight gain, liver and kidney weights, hemograme, liver and kidney function tests were monitored weekly during the experimental time. No mortalities were detected in the groups treated with Cys+OA. Rats treated with OA were decreased significantly in body weight gain, liver and kidney weight than other treated groups. OA caused anaemia, leucopenia, neutrophilia, evaluation of ALT, AST and AP activities, mild hyperglycemia hypoproteinaemia and elevation of urea and creatinine values. Cys+OA treatment minimized the toxic effect of OA on liver and kidney as evidenced by the tested parameters. Administration of Cys only resulted in a slight deviations than normal expecially in RBC and lymphocytic count, ALT activity and total proteins
Subject(s)
Animals, Laboratory , Aspergillus ochraceus , Rats , Liver/toxicity , Kidney/toxicity , Blood Glucose , Liver Function Tests , Kidney Function Tests , Protective Agents , Cysteine , Leukocyte CountSubject(s)
Cattle , Animals , Aspergillus ochraceus , Cattle , Diarrhea/veterinary , Ochratoxins/isolation & purification , ArgentinaABSTRACT
A produçäo de ocratoxina A foi estudada usando-se sementes selecionadas como substrato nutritivo estéril para Aspergillus ochraceus. A produçäo foi maior no girassol do que nas demais sementes examinadas. Dentre os três cultívares de sorgo testados, dois foram altamente resistentes ao ataque do fungo