RESUMO
The aim of this work was to investigate the early detection of anthracnose and soft rot diseases in cold stored strawberry fruit by evaluating the CO2 and volatile organic compounds (VOCs) released by the fungi Colletotrichum fragariae and Rhizopus stolonifer. Strawberries were stored at 5, 10 and 21⯰C (control group) and the VOCs and CO2 production of inoculated and non-inoculated strawberries were followed by gas chromatography. To evaluate and estimate the growth of both fungi, the CO2 data were fitted to the Gompertz model. Data of the VOCs released at the end of the fungal growth were analyzed using principal components analysis (PCA) to discriminate between infected and non-infected strawberries. The results showed that fungal growth was affected by temperature and C. fragariae had a maximum growth after 14.6â¯h at 5⯰C and R. stolonifer at 21⯰C after 45.2â¯h. On the other hand, through VOCs released by C. fragariae and R. stolonifer and PCA, four groups were obtained: a) strawberry infected with C. fragariae, stored at 10⯰C, b) strawberry infected with R. stolonifer, stored at 21⯰C, c) control group kept at 10⯰C and, d) strawberry infected with C. fragariae and control group (5 and 21⯰C), and strawberry infected with R. stolonifer at 5 and 10⯰C. In conclusion, CO2 and VOCs released by C. fragariae and R. stolonifer on strawberries could infer the presence of anthracnose and soft rot during storage of the fruit at low temperature.
Assuntos
Dióxido de Carbono/metabolismo , Temperatura Baixa , Colletotrichum/metabolismo , Fragaria/microbiologia , Frutas/microbiologia , Rhizopus/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Dióxido de Carbono/análise , Armazenamento de Alimentos , Análise Multivariada , Doenças das Plantas/microbiologia , Rhizopus/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/antagonistas & inibidoresRESUMO
Evolution of Rhizopus oryzae and Trichoderma reesei biomass in rice bran, their enzyme activity, and the profile of phenolic compounds released from the lignocellulosic matrices were determined and correlated by principal component analysis (PCA). PCA analysis confirms that cultivation of rice bran affected the release of methanol-soluble phenolic compounds (MSPC), ethanol-soluble phenolic compounds (ESPC), and bound phenolic compounds (BPC) positively, due to their enzymatic activity. The release of MSPC was influenced by the activity of cellulase and endoglucanase, which increased 110.6% and 136.3%, respectively, for Rhizopus oryzae and Trichoderma reesei. Gallic acid was the main component in the MSPC and ESPC compound fractions. Ferulic and syringic acids were found in its bound (BPC) form in the biomass. This study showed that bioactive compounds be released from lignocellulosic materials by fungus action and this process can be conducted to obtain specific phenolic compounds. PRACTICAL APPLICATION: Due the demand by natural compounds with biological activity, such as phenolic compounds, it is interesting to purpose alternatives to enhance their yield, like for instance, by fungal fermentation of lignocellulosic material. Therefore, understanding the relations among different phenolic compounds released and the production of fungal hydrolases during growth of Rhizopus oryzae and Trichoderma reesei in solid state cultivation using rice bran as a substrate is fundamental to control the process. This knowledge gets viable scale up to apply the phenolic compounds as preservative in food chain, because this becomes possible directing the process to obtain specific bioactive compounds in less time of cultivation and with low cost.
Assuntos
Celulase/metabolismo , Oryza/química , Fenóis/análise , Rhizopus/enzimologia , Trichoderma/enzimologia , Biomassa , Celulose/metabolismo , Ácidos Cumáricos/análise , Meios de Cultura , Fermentação , Ácido Gálico/análogos & derivados , Ácido Gálico/análise , Rhizopus/crescimento & desenvolvimento , Trichoderma/crescimento & desenvolvimentoRESUMO
The aim of this study was to evaluate the antifungal activity (in vitro) of thymol and carvacrol alone or in mixtures against Fusarium verticillioides and Rhizopus stolonifer, and to obtain primary growth models. Minimal inhibitory concentration (MIC) was evaluated with fungal radial growth with thymol or carvacrol concentrations (0-1600mg/l). Mixtures were evaluated using concentrations below MIC values. Radial growth curves were described by the modified Gompertz equation. MIC values of carvacrol were 200mg/l for both fungi. Meanwhile, MIC values of thymol were between 500 and 400mg/l for F verticillioides and R. stolonifer, respectively. A synergistic effect below MIC concentrations for carvacrol (100mg/l) and thymol (100-375 mg/l) was observed. Significant differences (p <0.05) between the Gompertz parameters for the antimicrobial concentrations and their tested mixtures established an inverse relationship between antimicrobial concentration and mycelial development of both fungi. Modified Gompertz parameters can be useful to determine fungistatic concentrations.
El objetivo de este trabajo fue evaluar la actividad antifúngica in vitro del timol y del carvacrol, solos o en mezclas, contra Fusarium verticillioides y Rhizopus stolonifer, y obtener modelos primarios de crecimiento. Se evaluó la concentración inhibitoria mínima (CIM) con el crecimiento radial, se ensayaron concentraciones de timol y carvacrol de 0 a 1.600 mg/l. Las mezclas se evaluaron utilizando concentraciones por debajo de los valores de CIM. Las curvas de crecimiento radial fueron descritas por la ecuación de Gompertz modificada. Se obtuvieron los siguientes valores de CIM: carvacrol, 200 mg/l para las 2 especies; timol, 500 mg/l y 400 mg/l para F. verticillioides y R. stolonifer, respectivamente. Se observó un efecto sinèrgico a concentraciones inferiores a las CIM para el carvacrol (100mg/l) y el timol (100-375 mg/l). Hubo diferencias significativas (p <0,05) entre los parámetros de crecimiento de Gompertz; se estableció que existe una relación inversa entre la concentración de los antimicrobianos y el desarrollo del micelio de ambos hongos.
Assuntos
Rhizopus , Timol , Monoterpenos , Fusarium , Rhizopus/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Fusarium/crescimento & desenvolvimento , CimenosRESUMO
A fermented solid containing lipases was produced by solid-state fermentation of Rhizopus microsporus on sugarcane bagasse enriched with urea, soybean oil, and a mineral solution. The dry fermented solid produced using R. microsporus (RMFS) was used to catalyze the synthesis of alkyl-esters by esterification in a solvent-free system containing ethanol and oleic acid (as a model system) or a mixture of fatty acids obtained from the physical hydrolysis of soybean soapstock acid oil (FA-SSAO) in subcritical water. The conversions were 93.5 and 84.1%, for oleic acid and FA-SSAO, respectively, at 48 h and 40 °C, at a molar ratio (MR) of ethanol to fatty acid of 5:1. A further increase in the MR to 10:1 improved the production of ethylic-esters, giving conversions at 48 h of 98 and 86% for oleic acid and FA-SSAO, respectively. The results obtained in this work foster further studies on scaling-up of an environmentally friendly process to produce biofuels.
Assuntos
Biocombustíveis , Celulose/química , Rhizopus/crescimento & desenvolvimento , Saccharum/química , EsterificaçãoRESUMO
The aim of this study was to evaluate the antifungal activity (in vitro) of thymol and carvacrol alone or in mixtures against Fusarium verticillioides and Rhizopus stolonifer, and to obtain primary growth models. Minimal inhibitory concentration (MIC) was evaluated with fungal radial growth with thymol or carvacrol concentrations (0-1600mg/l). Mixtures were evaluated using concentrations below MIC values. Radial growth curves were described by the modified Gompertz equation. MIC values of carvacrol were 200mg/l for both fungi. Meanwhile, MIC values of thymol were between 500 and 400mg/l for F. verticillioides and R. stolonifer, respectively. A synergistic effect below MIC concentrations for carvacrol (100mg/l) and thymol (100-375mg/l) was observed. Significant differences (p<0.05) between the Gompertz parameters for the antimicrobial concentrations and their tested mixtures established an inverse relationship between antimicrobial concentration and mycelial development of both fungi. Modified Gompertz parameters can be useful to determine fungistatic concentrations.
Assuntos
Fusarium , Monoterpenos , Rhizopus , Timol , Cimenos , Fusarium/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Rhizopus/crescimento & desenvolvimentoRESUMO
Metabolic control improves outcomes associated with mucormycosis. The aim of this study was to compare the in vitro proliferation of Rhizopus oryzae in blood of individuals with and without diabetes at different glycaemic levels. Ninety-five individuals were included. Blood samples from each participant were incubated with sporangiospores of R. oryzae. The germination, filamentation and growth of R. oryzae were compared at different time points. Four groups were defined, one without (group A, n = 30) and three with diabetes: group B (HbA1c ≤7%, N = 24), group C (HbA1c 7.1-9%, N = 20) and group D (HbA1c > 9%, N = 21). The percentage of germinated sporangiospores was higher in the group A after 6 h (group A 56% ± 3, group B 35% ± 4, group C 48% ± 4, group D 46% ± 1.4, p = 0.01), 12 h (group A 54% ± 1.4, group B 19% ± 4, group C 16% ± 1, group D 9.5% ± 5, p < 0.001) and 24 h (group A 29% ± 1, group B 12% ± 4, group C 13.5% ± 3.5, group D 12% ± 1, p < 0.01). The filamentation was higher in groups with diabetes. Group B showed higher filamentation grade than group A at 6 h (0.4 ± 0.04 vs 1 ± 0.09, p < 0.001) and 24 h (1.6 ± 0.05 vs 2.1 ± 0.1, p = 0.05). In conclusion, R. oryzae proliferation was higher among diabetic individuals, including good glycaemic control, than among non-diabetic individuals.
Assuntos
Sangue/microbiologia , Diabetes Mellitus/sangue , Suscetibilidade a Doenças/sangue , Rhizopus/crescimento & desenvolvimento , Esporos Fúngicos/crescimento & desenvolvimento , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise Química do Sangue , Proliferação de Células , Feminino , Germinação , Hemoglobinas Glicadas/análise , Índice Glicêmico , Carga Glicêmica , Humanos , Ferro/sangue , Masculino , Pessoa de Meia-Idade , Mucormicose/metabolismo , Mucormicose/microbiologiaRESUMO
In this study, we evaluated the efficacy of coatings comprising shrimp chitosan (CHI) and Mentha piperita L. (MPEO) or Mentha × villosa Huds (MVEO) essential oils to control mold infections caused by Aspergillus niger, Botrytis cinerea, Penicillium expansum and Rhizopus stolonifer in cherry tomato fruits (Solanum lycopersicum L.) during storage at room temperature (25°C for 12 days) and low temperature (12°C for 24 days). The effects of the coatings on the physicochemical and sensory characteristics of cherry tomato fruits during storage were also assessed. The minimum inhibitory concentration (MIC) of CHI against all test fungi was 8 mg/mL, whereas the MIC for both MPEO and MVEO was 5 µL/mL. Combinations of CHI at 4 mg/mL and MPEO or MVEO at 2.5 or 1.25 µL/mL strongly inhibited the mycelial growth and spore germination of target fungi. The coatings comprising CHI and MPEO or CHI and MVEO at the different tested concentrations delayed the growth of decay-causing fungi in artificially contaminated tomato fruit during storage at either room temperature or low temperature. The assayed coatings preserved the quality of cherry tomato fruit during storage, in terms of physicochemical and sensory attributes. These results indicate that coatings comprising CHI and MPEO or CHI and MVEO represent promising postharvest treatments to prevent common postharvest mold infections in cherry tomato fruit during storage without affecting the quality of the fruit.
Assuntos
Quitosana/farmacologia , Conservação de Alimentos/métodos , Frutas/microbiologia , Mentha piperita/metabolismo , Óleos Voláteis/farmacologia , Solanum lycopersicum/microbiologia , Animais , Aspergillus niger/crescimento & desenvolvimento , Botrytis/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Penaeidae/metabolismo , Penicillium/crescimento & desenvolvimento , Rhizopus/crescimento & desenvolvimentoRESUMO
Current models that describe the extension of fungal hyphae and development of a mycelium either do not describe the role of vesicles in hyphal extension or do not correctly describe the experimentally observed profile for distribution of vesicles along the hypha. The present work uses the n-tanks-in-series approach to develop a model for hyphal extension that describes the intracellular transport of nutrient to a sub-apical zone where vesicles are formed and then transported to the tip, where tip extension occurs. The model was calibrated using experimental data from the literature for the extension of reproductive aerial hyphae of three different fungi, and was able to describe different profiles involving acceleration and deceleration of the extension rate. A sensitivity analysis showed that the supply of nutrient to the sub-apical vesicle-producing zone is a key factor influencing the rate of extension of the hypha. Although this model was used to describe the extension of a single reproductive aerial hypha, the use of the n-tanks-in-series approach to representing the hypha means that the model has the flexibility to be extended to describe the growth of other types of hyphae and the branching of hyphae to form a complete mycelium.
Assuntos
Aspergillus/crescimento & desenvolvimento , Hifas/crescimento & desenvolvimento , Modelos Estatísticos , Phycomyces/crescimento & desenvolvimento , Rhizopus/crescimento & desenvolvimento , Aspergillus/metabolismo , Transporte Biológico , Simulação por Computador , Hifas/metabolismo , Maltose/metabolismo , Modelos Biológicos , Phycomyces/metabolismo , Rhizopus/metabolismo , Vesículas Transportadoras/metabolismoRESUMO
The aim of this study was to extract chitosan (CHI) from Mucor circinelloides UCP 050 grown in a corn steep liquor (CSL)-based medium under optimized conditions and to assess the efficacy of the obtained CHI to inhibit the post-harvest pathogenic fungi Aspergillus niger URM 5162 and Rhizopus stolonifer URM 3482 in laboratory media and as a coating on table grapes (Vitis labrusca L.). The effect of CHI coating on some physical, physicochemical and sensory characteristics of the fruits during storage was assessed. The greatest amount of CHI was extracted from M. circinelloides UCP 050 grown in medium containing 7 g of CSL per 100 mL at pH 5.5 with rotation at 180 rpm. CHI from M. circinelloides UCP 050 caused morphological changes in the spores of the fungal strains tested and inhibited mycelial growth and spore germination. CHI coating delayed the growth of the assayed fungal strains in artificially infected grapes, as well as autochthonous mycoflora during storage. CHI coating preserved the quality of grapes during storage, as measured by their physical, physicochemical and sensory attributes. These results demonstrate that edible coatings derived from M. circinelloides CHI could be a useful alternative for controlling pathogenic fungi and maintaining the post-harvest quality of table grapes.
Assuntos
Aspergillus niger/efeitos dos fármacos , Quitosana/farmacologia , Conservação de Alimentos/métodos , Mucor/química , Rhizopus/efeitos dos fármacos , Vitis/microbiologia , Aspergillus niger/crescimento & desenvolvimento , Quitosana/metabolismo , Armazenamento de Alimentos , Mucor/crescimento & desenvolvimento , Mucor/metabolismo , Rhizopus/crescimento & desenvolvimento , Vitis/química , Vitis/crescimento & desenvolvimentoRESUMO
The leaves and bark of Croton cajucara, a shrub from the Amazon region, have been used in folk medicine to treat diabetes, malaria, and gastrointestinal and liver disorders. The essential oil from the leaves, rich in linalool, presented antileishmanial and antimicrobial activities. A chemotype of this species was found with an essential oil rich in 7-hydroxycalamenene. During our studies of the C. cajucara essential oil, we isolated 7-hydroxycalamenene at > 98â% purity. The minimum inhibitory concentration of 7-hydroxycalamenene against Absidia cylindrospora, Cunninghamella elegans, Mucor circinelloides, Mucor circinelloides f. circinelloides, Mucor mucedo, Mucor plumbeus, Mucor ramosissimus, Rhizopus microsporus, Rhizopus oryzae, and Syncephalastrum racemosum ranged from 19.53 to 2500 µg/mL. The reference drug used, amphotericin B, presented a minimum inhibitory concentration ranging from 0.085 µg/mL to 43.87 µg/mL. 7-Hydroxycalamenene also altered spore differentiation and total lipid content. Ultrastructural analysis by transmission electron microscopy showed significant alterations in the cellular structure of R. oryzae.
Assuntos
Croton/química , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Óleos de Plantas/farmacologia , Rhizopus/efeitos dos fármacos , Sesquiterpenos/farmacologia , Zigomicose/tratamento farmacológico , Monoterpenos Acíclicos , Anfotericina B/farmacologia , Medicina Tradicional , Testes de Sensibilidade Microbiana , Monoterpenos/química , Monoterpenos/isolamento & purificação , Monoterpenos/farmacologia , Micélio/efeitos dos fármacos , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Casca de Planta/química , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Folhas de Planta/química , Óleos de Plantas/química , Óleos de Plantas/isolamento & purificação , Rhizopus/crescimento & desenvolvimento , Rhizopus/ultraestrutura , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificaçãoRESUMO
The antifungal activities of chitosan and oligochitosan have been used to control postharvest decay of the fruits. The effect of chitosan and oligochitosan on mycelium growth, spore germination, and mitochondrial function of Rhizopus stolonifer was evaluated in order to establish a connection between fungus development and the main organelle in charge to provide energy to the cell. The mycelium growth of R. stolonifer was significantly reduced on minimum media amended with chitosan or oligochitosan. The highest antifungal indexes were obtained on media containing chitosan or oligochitosan at 2.0 mg ml(-1). Microscopic observation showed that chitosan and oligochitosan affected the spore germination and hyphae morphology. Both polymers increased oxygen consumption of R. stolonifer. Respiratory activity was restored with NADH in permeabilized treated and untreated cells, and was inhibited with rotenone and flavones. Complex III and IV were inhibited by antimycin A and cyanide, respectively, in treated and untreated cells. Chitosan and oligochitosan increased NADH dehydrogenase activity in isolated mitochondria. However, there were not changes in the cytochrome c oxidase and ATPase activities by effect of these polymers. These results suggest that both chitosan and oligochitosan affect the development of R. stolonifer and might be implicated in the mitochondrial dysfunction.
Assuntos
Antifúngicos/metabolismo , Quitosana/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/fisiologia , Rhizopus/efeitos dos fármacos , Rhizopus/crescimento & desenvolvimento , Adenosina Trifosfatases/metabolismo , Meios de Cultura/química , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Microscopia , Micélio/citologia , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , NAD/metabolismo , Oxigênio/metabolismo , Rhizopus/citologia , Esporos Fúngicos/citologia , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimentoRESUMO
BACKGROUND: Fungal contamination of poultry feed causes economic losses to industry and represents a potential risk to animal health. The aim of the present study was to analyze the effectiveness of whey fermented with kefir grains as additive to reduce fungal incidence, thus improving feed safety. RESULTS: Whey fermented for 24 h at 20 °C with kefir grains (100 g L(-1) ) reduced conidial germination of Aspergillus flavus, Aspergillus parasiticus, Aspergillus terreus, Aspergillus fumigatus, Penicillium crustosum, Trichoderma longibrachiatum and Rhizopus sp. Poultry feed supplemented with fermented whey (1 L kg(-1) ) was two to four times more resistant to fungal contamination than control feed depending on the fungal species. Additionally, it contained kefir microorganisms at levels of 1 × 10(8) colony-forming units (CFU) kg(-1) of lactic acid bacteria and 6 × 10(7) CFU kg(-1) of yeasts even after 30 days of storage. CONCLUSION: Fermented whey added to poultry feed acted as a biopreservative, improving its resistance to fungal contamination and increasing its shelf life.
Assuntos
Ração Animal/microbiologia , Fermentação , Microbiologia de Alimentos/métodos , Fungos , Proteínas do Leite/metabolismo , Aves Domésticas , Animais , Aspergillus/efeitos dos fármacos , Aspergillus/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Produtos Fermentados do Leite/microbiologia , Aditivos Alimentares , Contaminação de Alimentos/prevenção & controle , Conservação de Alimentos/métodos , Leite/microbiologia , Penicillium/efeitos dos fármacos , Penicillium/crescimento & desenvolvimento , Rhizopus/efeitos dos fármacos , Rhizopus/crescimento & desenvolvimento , Trichoderma/efeitos dos fármacos , Trichoderma/crescimento & desenvolvimento , Proteínas do Soro do LeiteRESUMO
Rhizopus oligosporus has proven beneficial in the detoxification of lupin seeds. The fermentation process is mainly affected by the initial pH in the medium. In the range of growth of mold, there are maximum enzymatic activities in pH of 3.5 and 5.5. Metabolism change occurs at these pH levels; therefore, we studied the growth, pH changes, dry matter intake, and alkaloid degradation within 48 h of fermentation. Cultures of lupin agar (LA) with pH of 3.5 and 5.5 were made in Petri dishes with lupin flour. Results showed pH directly affects the degradation of alkaloids and fungal growth. Detoxification levels achieved were 16.58 and 63.23 % in treatments LA 3.5 and LA 5.5, respectively. Fungal growth was 0.919 mg/cm(2) in LA 3.5 and 1.081 mg/cm(2) in LA 5.5. Maximum degradation rate in LA 5.5 was given between 16 and 20 h, which coincided with maximum fungal growth. Despite having similar dry matter intake in both treatments, a pH of 3.5 did not show the same degree of detoxification. The analysis with exponential, yield of growth, yield of dry matter intake and luedeking and piret equations, confirm the relation between intake and growth with detoxification. Dry matter intake equation predicts with R (2) of 0.94 the detoxification in LA 5.5. A pH of 5.5 is directly related with detoxification and fungal development.
Assuntos
Alcaloides/metabolismo , Lupinus/química , Quinolizidinas/metabolismo , Rhizopus/metabolismo , Alcaloides/isolamento & purificação , Biotransformação , Meios de Cultura/química , Concentração de Íons de Hidrogênio , Quinolizidinas/isolamento & purificação , Rhizopus/crescimento & desenvolvimento , Sementes/química , Fatores de TempoRESUMO
This study evaluated the efficacy of the combined application of chitosan (CHI) and Origanum vulgare L. essential oil (OV) in the inhibition of Rhizopus stolonifer URM 3728 and Aspergillus niger URM 5842 on laboratory media and on grapes (Vitis labrusca L.) and its influence on the physical, physicochemical and sensory characteristics of the fruits during storage (25 °C, 12 days and 12 °C, 24 days). The application of mixtures of different CHI and OV concentrations (Minimum Inhibitory Concentration - MIC, 1/2 MIC and 1/4 MIC) inhibited the mycelial growth of the test fungi. The application of CHI and OV at sub-inhibitory concentrations (CHI 1/2 MIC + OV 1/4 MIC; CHI 1/2 MIC + OV 1/2 MIC) inhibited spore germination and caused morphological changes in fungal spores and mycelia, in addition to inhibiting the growth of the assayed fungi strains in artificially infected grapes as well as the autochthonous mycoflora of grapes stored at both room and cold temperature. In general, the application of a coating composed of CHI and OV at sub-inhibitory concentrations preserved the quality of grapes as measured by their physical and physicochemical attributes, while some of their sensory attributes improved throughout the assessed storage time. These results demonstrate the potential of the combination of CHI and OV at sub-inhibitory concentrations to control post-harvest pathogenic fungi in fruits, in particular, R. stolonifer and A. niger in grapes.
Assuntos
Aspergillus niger/efeitos dos fármacos , Quitosana/farmacologia , Conservação de Alimentos/métodos , Óleos Voláteis/farmacologia , Origanum/química , Extratos Vegetais/farmacologia , Rhizopus/efeitos dos fármacos , Vitis/microbiologia , Aspergillus niger/crescimento & desenvolvimento , Quitosana/química , Armazenamento de Alimentos , Frutas/química , Frutas/efeitos dos fármacos , Frutas/microbiologia , Testes de Sensibilidade Microbiana , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Óleos Voláteis/química , Extratos Vegetais/química , Rhizopus/crescimento & desenvolvimento , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento , Vitis/química , Vitis/efeitos dos fármacosRESUMO
The antimicrobial activity of oregano has been attributed mainly to the presence of volatile compounds found in its essential oil (EO), mainly carvacrol and thymol. The search for antimicrobial activity of oregano EO with different concentrations of thymol and carvacrol, can lead to products with a wider range of applications. The aim of this work was to describe the in vitro antifungal effect of Mexican oregano (Lippia berlandieri Schauer) EO fractions on the growth of Aspergillus, Penicillium, and Rhizopus sp. The Mexican oregano EO fractions studied had different concentrations of carvacrol, which decreased from fraction 1 to 5 (81% to 23%), while thymol content increased from 3% to 64%. Fungal inhibition was evaluated on a wheat flour-based medium with EO fractions concentrations ranging from 50 to 200 mg/kg. Radial growth curves were fitted using the modified Gompertz model (R(2)(adj) = 0.989 ± 0.01). No significant differences (P > 0.05) were found with the different composition of the Mexican oregano EO fractions; nevertheless, fraction concentration presented significant (P < 0.05) mold inhibition as concentration increased. Rhizopus sp. (Rh18) showed a linear reduction on specific growth rate, on the maximum mold growth at the stationary phase, and an increase in the lag time as the concentration of the oregano EO increased; mold growth inhibition were achieved at 150 mg/kg in fractions 1 to 4, and at 100 mg/kg for fraction 5. Aspergillus sp. (As6) and Penicillium sp. (Pe36) were inhibited at 150 and 200 mg/kg, respectively. Results obtained suggest that Mexican oregano EO (Lippia berlandieri Schauer) compounds could be used as antimicrobial agents to prevent fungal growth in bakery products.
Assuntos
Antifúngicos/farmacologia , Farinha/microbiologia , Óleos Voláteis/farmacologia , Origanum/química , Triticum/microbiologia , Cimenos , Contaminação de Alimentos/prevenção & controle , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , México , Testes de Sensibilidade Microbiana , Monoterpenos/farmacologia , Penicillium/efeitos dos fármacos , Penicillium/crescimento & desenvolvimento , Óleos de Plantas/farmacologia , Rhizopus/efeitos dos fármacos , Rhizopus/crescimento & desenvolvimento , Timol/farmacologia , Triticum/químicaRESUMO
Mucormycoses are emerging infections that have high rates of morbidity and mortality. They show high resistance to antifungal agents, and there is a limited therapeutic arsenal currently available, therefore, there is a great need to give priority to testing therapeutic agents for the treatment of mucormycosis. Along this line, the use of essential oils and phytoconstituents has been emphasized as a new therapeutic approach. The objective of this work was to investigate the antifungal activity of the essential oil (EO) of Thymus vulgaris, and its constituents thymol and p-cymene against Rhizopus oryzae, through microbiological screening, determination of minimal inhibitory concentration (MICs) and minimal fungicidal concentration (MFCs), effects on mycelial growth and germination of sporangiospores and interaction with ergosterol. The MIC of EO and thymol varied 128-512 µg/mL, but the MFC of EO and thymol varied 512-1024 µg/mL and 128-1024 µg/mL, respectively. The results also showed that EO and thymol significantly inhibited mycelial development and germination of sporangiospores. Investigation of the mechanism of antifungal action showed that EO and thymol interact with ergosterol. These data indicate that EO of T. vulgaris and thymol possess strong antifungal activity, which can be related to their interaction with ergosterol, supporting the possible use of these products in the treatment of mucormycosis.
Assuntos
Antifúngicos/farmacologia , Ergosterol/metabolismo , Óleos de Plantas/farmacologia , Rhizopus/efeitos dos fármacos , Thymus (Planta)/química , Cimenos , Testes de Sensibilidade Microbiana , Monoterpenos/farmacologia , Óleos Voláteis/farmacologia , Rhizopus/crescimento & desenvolvimento , Timol/farmacologiaRESUMO
The fungi strains were tested in Bioscreen automated system to select the best nutritional source. Following, shaking submserse cultures were studied in media containing sole carbon or nitrogen source. The growth of these strains improved in media containing vegetable oil, with high concentration of lipids. The high concentration of γ-linolenic acid was obtained with M. circinelloides in culture containing sesame oil.
Linhagens de fungos foram testadas em sistema automatizado Bioscreen para selecionar melhor fonte nutricional. Em seguida, foram estudadas culturas submersas em meios contendo uma única fonte de carbono e de nitrogênio. As linhagens contendo alta concentração de lipídeos tiveram melhor crescimento em meio contendo óleos de gergelim ou de dendê. Maior concentração de ácido γ-linolênico foi obtida com M. circinelloides nas culturas em óleo de gergelim.
Assuntos
Ácidos Araquidônicos/análise , Ácidos Linolênicos/análise , Lipídeos/análise , Mucorales/crescimento & desenvolvimento , Óleos de Plantas/análise , Rhizopus/crescimento & desenvolvimento , Zigomicose , Microbiologia Industrial , Métodos , MétodosRESUMO
Four phytopathogenic fungi were cultivated up to six days in media containing chitooligosaccharide mixtures differing in average DP and FA. The three different mixtures were named Q3 (which contained oligosaccharides of DP2-DP10, with DP2-DP7 as main components), Q2 (which contained oligosaccharides of DP2-DP12, with DP2-DP10 as main components) and Q1 (which derived from Q2 and contained oligomers of DP5-DP8 with hexamer and a heptamer as the main components). The novel aspect of this work is the description of the effect of mixtures of oligosaccharides with different and known composition on fungal growth rates. The growth rate of Alternaria alternata and Rhizopus stolonifer was initially inhibited by Q3 and Q2 at higher concentrations. Q1 had a growth stimulating effect on these two fungi. Growth of Botrytis cinerea was inhibited by Q3 and Q2, while Q1 had no effect on the growth of this fungus. Growth of Penicillium expansum was only slightly inhibited by higher concentrations of sample Q3, while Q2 and Q1 had no effect. The inhibition of growth rates or their resistance toward chitooligosaccharides correlated with the absence or presence of chitinolytic enzymes in the culture media, respectively.
Assuntos
Alternaria/crescimento & desenvolvimento , Botrytis/crescimento & desenvolvimento , Quitina/metabolismo , Oligossacarídeos/metabolismo , Penicillium/crescimento & desenvolvimento , Doenças das Plantas/microbiologia , Rhizopus/crescimento & desenvolvimento , Acetilação , Alternaria/enzimologia , Botrytis/enzimologia , Quitina/análogos & derivados , Meios de Cultura , Frutas/microbiologia , Cinética , Espectrometria de Massas , Oligossacarídeos/química , Penicillium/enzimologia , Rhizopus/enzimologiaRESUMO
The alcoholic beverage parakari is a product of cassava (Manihot esculenta Crantz) fermentation by Amerindians of Guyana. While fermented beverage production is nearly universal among indigenous Amazonians, parakari is unique among New World beverages because it involves the use of an amylolytic mold (Rhizopus sp., Mucoraceae, Zygomycota) followed by a solid substratum ethanol fermentation. The mycological significance of this dual fermentation process previously was unrecognized. A detailed study of parakari fermentation was made in the Wapisiana Amerindian village of Aishalton, South Rupununi, Guyana. Thirty steps were involved in parakari manufacture, and these exhibited a high degree of sophistication, including the use of specific cassava varieties, control of culture temperature and boosting of Rhizopus inoculum potential with purified starch additives. During the fermentation process, changes in glucose content, pH, flavor, odor and culture characteristics were concomitant with a desirable finished product. Parakari is the only known example of an indigenous New World fermentation that uses an amylolytic mold, likely resulting from domestication of a wild Rhizopus species in the distant past. Parakari production is remarkably similar to dual fermentations of Asia, yet it was independently derived.
Assuntos
Bebidas , Glucose/metabolismo , Manihot/metabolismo , Rhizopus/metabolismo , Amido/metabolismo , Fermentação , Guiana , Manihot/química , Plantas Comestíveis/metabolismo , Rhizopus/crescimento & desenvolvimento , Rhizopus/isolamento & purificaçãoRESUMO
Marigold flowers are the main natural source of xanthophylls, and marigold saponified extract is used as an additive in several food and pharmaceutical industries. In this work, the use of a solid-state fermentation (ensilage) process for increasing the yield of xanthophylls extracted from fermented marigold flowers was examined. The process consisted of a mixed culture of three microorganisms (Flavobacterium IIb, Acinetobacter anitratus, and Rhizopus nigricans), part of the normal microbiota associated with the marigold flower. These microorganisms had been previously isolated, and were identified as relevant for the ensilage process due to their capacity to produce cellulolytic enzymes. Based on experimental design strategies, optimum operation values were determined for aeration, moisture, agitation, and marigold-to-inoculum ratio in the proposed solid-state fermentation equipment, leading to a xanthophylls yield of 17.8-g/kg dry weight. The optimum achieved represents a 65% increase with respect to the control. HPLC analysis indicated conservation of extracted oleoresin. Based on the experimental results, interactions were identified that could be associated with the heat and mass-transfer reactions taking place within the bioreactor. The insight gained allows conditions that limit growth and metabolic activity to be avoided.