Microbiologia
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11840
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197 resultados
Resultados da Pesquisa
Item Liquid-liquid equilibria in aqueous two-phase ethanol/salt systems at different temperatures and their application to anthocyanins extraction(Food Science and Technology, 2019-05-16) Sampaio, Fábio Coelho; Caldeira, Ana Clara Rocha; Converti, Attilio; Lima, William James Nogueira; Faria, Janaína Teles deAqueous two-phase systems (ATPS) are formed by mixtures of chemical species that, under certain conditions, separate into two immiscible phases, with water as the major component in global terms and, at lower concentrations, polymers, salts, ionic liquids and alcohols, depending on the system type. Different parameters influence ATPS equilibrium such as temperature, alcohol carbon chain size, salt type, pH, etc. The present work aimed to obtain the binodal curves for ATPS made up of ethanol, sodium citrate/ammonium sulfate and water at different temperatures (15, 25 and 35 °C) as well as to evaluate the potential of the ethanol/ammonium sulfate system in anthocyanins partition. The results showed that the increase in temperature did not alter the biphasic region in the temperature range investigated, not influencing the formation of phases. Nonlinear equations were satisfactorily fitted to binodal curves data, except for sodium citrate-containing ATPS at 15 °C. Higher concentration of the overall mixture resulted in longer tie-line of ammonium sulphate-containing ATPS. Higher values of partition coefficient and recovery yield of Syzygium cumini fruit anthocyanins were obtained at longer tie-lines.Item Padrão de integração de pAN7-1 em mutantes de Magnaporthe grisea com patogenicidade alterada em arroz(Summa Phytopathologica, 2010-01) Queiroz, Marisa Vieira de; Marchi, Carlos Eduardo; Brommonschenkel, Sérgio Hermínio; Borges, Mírian de Freitas; Mizubuti, Eduardo Seiti G.Ensaios foram conduzidos para verificar a presença, o número de cópias e de sítios de integração de pAN7-1 no genoma de mutantes de M. grisea I-22 com patogenicidade alterada em arroz. Foram analisados T41, T93, T251 (gerados por mutagênese REMI) e T108 (oriundo de mutagênese convencional), os quais exibiram diferentes fenótipos mutantes. O DNA total desses mutantes foi submetido à reação em cadeia de polimerase (PCR) e às análises de hibridização com o vetor (Southern blot). A presença de pAN7-1 no genoma de todos os mutantes foi confirmada por PCR. Segundo as análises de Southern blot, T41 exibiu duas integrações do vetor, ambas na forma de cópia única. No genoma de T93 também foram detectados dois sítios de inserção de pAN7-1, um dos quais envolvendo múltiplas cópias do vetor. Os resultados indicaram a presença de apenas uma cópia do vetor em um único sítio nos genomas de T108 e T251. O padrão de integração em T251 foi o único a sugerir a ocorrência de evento REMI. As diferenças quanto ao tamanho dos fragmentos com homologia a pAN7-1 refletiram a possível aleatoriedade dos eventos de integração no genoma de M. grisea. Os resultados evidenciaram o potencial de REMI para a mutagênese insercional de M. grisea, quando conduzida com pAN7-1 e HindIIIItem Características físico-químicas e microbiológicas de morango minimamente processado(Food Science and Technology, 2010-01) Ponce, Adriana dos Reis; Bastiani, Maria Inês Dantas; Minim, Valéria Paula; Vanetti, Maria Cristina DantasO presente trabalho teve como objetivo avaliar as alterações físico-químicas e microbiológicas de morangos submetidos ao processamento mínimo. Foram avaliados os efeitos da lavagem com cloreto de cálcio ou polietilenoglicol na microbiota contaminante e na textura dos morangos e da sanificação com ozônio gasoso ou clorado orgânico. Análises de textura, cor, perda de massa e microbiota contaminante foram feitas durante o armazenamento a 5 °C por 12 dias em embalagens envoltas com uma a quatro camadas de filme de cloreto de polivinil (PVC). A adição de até 1,5% de cloreto de cálcio ou de 0,5% de polietilenoglicol na água de lavagem não garantiu a manutenção da textura do morango ao final do período de armazenamento. A ozonização dos morangos por 60 minutos foi mais efetiva para reduzir (p < 0,05) a contagem de mesófilos aeróbios, fungos e leveduras e coliformes do que a ozonização por 30 minutos ou a imersão em solução de clorado orgânico. Os morangos armazenados em embalagens recobertas com três camadas de filme PVC apresentaram aumento na textura e na intensidade de escurecimento e redução na microbiota contaminante. Os principais fungos isolados de morangos minimamente processados durante o armazenamento pertenciam ao gênero Fusarium e à espécie Cladosporium cladosporioides.Item Antimicrobial activity and mineral composition of shiitake mushrooms cultivated on agricultural waste(Brazilian Archives of Biology and Technology, 2011-09) Kasuya, Maria Catarina Megumi; Casaril, Kérley Braga Pereira Bento; Vanetti, Maria Cristina DantasThe antimicrobial activity and mineral composition of shiitake mushrooms were evaluated in four isolates of Lentinula edodes. Mushrooms were cultivated on artificial logs, based on eucalyptus sawdust enriched with 20% rice, wheat, or soybean bran, or combination of 10% of two of these supplements. The substrates were humidified with a 0.1% mate tea extract or water. Logs of Eucalyptus grandis were also used to cultivate the shiitake mushrooms. The antimicrobial activity of an aqueous extract, corresponding to 40 mg of mushroom dry matter, was in some cases, depending on the isolate, able to inhibit both Bacillus subtilis and Escherichia coli K-12, independent of substrate composition or the growth stage of the mushrooms. Nitrogen, phosphorus, potassium, magnesium and calcium concentrations varied according to the substrate on which the mushrooms were cultivated, being, generally, higher with cultivation on artificial rather than natural eucalyptus logs. It could be concluded that, in addition to the fungal isolate, substrate composition and, processing methods must be considered during the production of antimicrobial substance(s) as well as in the mushroom nutritional compositionItem Production and regeneration of protoplasts from orchid Mycorrhizal Fungi Epulorhiza repens and Ceratorhiza sp.(Brazilian Archives of Biology and Technology, 2010-01) Coelho, Irene da Silva; Queiroz, Marisa Vieira de; Costa, Maurício Dutra; Kasuya, Maria Catarina Megumi; Araújo, Elza Fernandes deThe aim of this work was to study the standardization of conditions to obtain and regenerate Epulorhiza repens and Ceratorhiza sp. protoplasts. For E. repens, the largest number of protoplasts (8.0 × 106 protoplasts/mL) was obtained in 0.6 M KCl, using 15 mg/mL of Lysing Enzymes, and 2-day-old fungal mycelium. When 0.5 M sucrose was used as osmotic stabilizer, the highest frequency of regeneration was achieved (8.5 %); 80.0 % of protoplasts were nucleated, and 20.0 % anucleated. For Ceratorhiza sp., the largest number of protoplasts (4.0 × 107 protoplasts/mL) was achieved in 0.6 M NaCl, when 15 mg/mL of Lysing Enzymes and 15mg/mL of Glucanex, with 2-day-old fungal mycelium were used. The highest frequency of regeneration was 6.7 % using 0.5 M sucrose as osmotic stabilizer; 88.8 % of protoplasts were nucleated, and 11.2 % anucleated.Item Aumento da disponibilidade de N via deposição atmosférica e fenologia reprodutiva de Habenaria caldensis Kraenzl. (Orchidaceae) no Parque Estadual do Itacolomi (PEIT) – MG, Brasil(Biota Neotropica, 2011-04) Pylro, Victor Satler; Cruz, Eduardo dos Santos; Duarte, Gabriela Frois; Kozovits, Alessandra RodriguesAlong with the increased concentration of CO 2 , the atmospheric deposition of nitrogen is currently considered one of the most important factors of change in the functioning of native ecosystems and has caused drastic changes in their floristic composition and nutrient cycling in the northern hemisphere. In tropical and subtropical systems, however, the largest holders of the plants diversity, little is known about the effects of the nitrogen enrichment via deposition on their performance. Understanding the magnitude and direction of the responses of the orchids to the increase of the concentration of available nitrogen might be helpful to modeling of rock outcrops population dynamics in response to global changes. We evaluated the responses of flowering and fruiting in plants of Habenaria caldensis Kraenzl. (Orchidaceae), a species widely distributed in Minas Gerais, as a result of increased nitrogen availability through fertilization with ammonium nitrate, in situ, by spraying. In response to the addition of N, anthesis occurred about 15 days earlier compared to individuals of the control group. The results of this study demonstrated that the increased availability of N via atmospheric deposition can affect in a short term the ecology of orchids and possibly other plants from rock outcrops by changing their phenological and allometric patterns. In a medium and long term, such changes can have an important impact on the dynamics of populations and communities of this vegetation type.Item Cyrtopodium paludicolum germination with two Tulasnella isolates(Acta Botanica Brasilica, 2018-01) Carvalho, Otieres Cirino de; Paiva Neto, Vespasiano Borges de; Padilha, Daly Roxana Castro; Veloso, Tomás Gomes Reis; Bocayuva, Melissa Faust; Soares, Deanna Carla Oliveira; Kasuya, Maria Catarina MegumiSymbiosis between orchid seeds and mycorrhizal fungi has been reported to be a determining factor in the success of germination and protocorm development in vitro. Th e aim of this study was to isolate and identify by molecular analysis the mycorrhizal fungus associated with Cyrtopodium paludicolum, and to evaluate its effi ciency in facilitating seed germination and development. Germination experiments were carried out using a fungus isolated from C. paludicolum (CH01) and Epidendrum secundum (M65), which has been successfully used a number of times in symbiotic germination. Th e experiments were conducted in a completely randomized design with treatments of CH01, M65 as well as under asymbiotic conditions. Th e mycobiont CH01 was successfully isolated from Cyrtopodium paludicolum and identifi ed as Tulasnella sp. Treatments with both fungi reached a higher germination percentage than under asymbiotic conditions, indicating no specifi city in the relationship between Cyrtopodium paludicolum and the fungi. Th e results presented have the potential to advance research into the propagation and conservation of C. paludicolum, a native of the Cerrado biome.Item In vitro culture of Gigaspora decipiens and Glomus clarum in transformed roots of carrot: the influence of temperature and pH(Acta Scientiarum. Agronomy, 2013-07) Kasuya, Catarina Megumi; Costa, Francilina Araújo; Haddad, Lydice Sant'Anna Meira; Oton, Wagner Campos; Costa, Maurício Dutra; Borges, Arnaldo ChaerMonoxenic cultures of arbuscular mycorrhizal fungi (AMF) in transformed roots have been used to better understand the symbiosis with these fungi, but few species have been successfully established in vitro. The object was to establish monoxenic cultures of Gigaspora decipiens and Glomus clarum and to verify the effects of temperature and pH on spore formation. Cultures were established from superficially disinfested spores that were germinated on an agar and water. After germination, the spores were transferred to Petri dishes containing transformed carrot roots. After 4-6 days formed newly formed spores and structures typical. The effects of temperature (22, 25, 28 or 32ºC) and pH (4.0, 4.5, 5.5 or 6.5) on the production of spores were assessed over three months, resulting in sigmoidal growth curves. The spore increased from 22ºC, reaching higher values 28oC and 32oC there was a reduction in the production. The highest spore production of G. decipiens occurred in a pH of 6.5, whereas for G. clarum was pH of 4.0. The cultivation of other species is still necessary to elucidate particular aspects of the symbiosis that so far are unclear, including the effects of environmental factors on the production of spores of different AMF species.Item Screening and characterization of prophages in Desulfovibrio genomes(Scientific Reports, 2018) Crispim, Josicelli Souza; Dias, Roberto Sousa; Vidigal, Pedro Marcus Pereira; Sousa, Maíra Paula de; Silva, Cynthia Canêdo da; Santana, Mateus Ferreira; Paula, Sérgio Oliveira deBacteria of the genus Desulfovibrio belong to the group of Sulphate Reducing Bacteria (SRB). SRB generate significant liabilities in the petroleum industry, mainly due to their ability to microbiologically induce corrosion, biofilm formation and H2S production. Bacteriophages are an alternative control method for SRB, whose information for this group of bacteria however, is scarce. The present study developed a workflow for the identification of complete prophages in Desulfovibrio. Poly-lysogenesis was shown to be common in Desulfovibrio. In the 47 genomes analyzed 53 complete prophages were identified. These were classified within the order Caudovirales, with 69.82% belonging to the Myoviridade family. More than half the prophages identified have genes coding for lysozyme or holin. Four of the analyzed bacterial genomes present prophages with identity above 50% in the same strain, whose comparative analysis demonstrated the existence of colinearity between the sequences. Of the 17 closed bacterial genomes analyzed, 6 have the CRISPR-Cas system classified as inactive. The identification of bacterial poly-lysogeny, the proximity between the complete prophages and the possible inactivity of the CRISPR-Cas in closed bacterial genomes analyzed allowed the choice of poly-lysogenic strains with prophages belonging to the Myoviridae family for the isolation of prophages and testing of related strains for subsequent studies.Item In vitro probiotic potential and anti-cancer activity of newly isolated folate-producing Streptococcus thermophilus strains(Frontiers in Microbiology, 2018-09) Duarte, Vinicius da Silva; Tarrah, Armin; Castilhos, Juliana de; Rossi, Rochele Cassanta; Ziegler, Denize Righetto; Corich, Viviana; Giacomini, AlessioMost probiotic strains commercially available today are lactic acid bacteria. Withinthis functional group, Streptococcus thermophilus is a thermophilic species widely used as starter culture for a huge number of dairy products. Besides being rapid acidifiers, many S. thermophilus strains are able to produce and release folate during growth but, unfortunately, they are seriously impaired during passage through the human gastrointestinal tract. In this work, we studied eight S. thermophilus strains isolated from dairy environments in Italy, which already had shown good technological properties, to evaluate their possible probiotic potential and cytotoxicity against cancer cells in vitro. All strains were also evaluated for some health-related properties such as susceptibility to most common antibiotics, hemolytic activity, resistance to simulated gastrointestinal conditions, bile salts hydrolytic activity, production of folate, adhesion to HT-29 human colorectal adenocarcinoma cells and cytotoxic activity against cancer cells and production of biogenic amines. Results revealed that two fast acidifying S. thermophilus strains were found to possess in vitro probiotic properties along with anticancer activity and production of folate. These properties resulted similar and, in some cases, superior to those of Lactobacillus rhamnosus GG, a well-known commercial probiotic strain. These findings encourage further in vivo studies to evaluate the actual health benefits of these strains on the human host.