Microbiologia
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11840
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Resultados da Pesquisa
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 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 Levantamento fitossociológico de plantas daninhas em pastagens no município de Nova Olímpia-MT(Revista Agraria, 2013-11) Mendes, Kassio Ferreira; Inoue, Miriam Hiroko; Iskierski, Daiane; Ben, Ronei; Conciani, Paulo Alberto; Pereira, Rafael Luiz; Dallacort, RivanildoO objetivo do trabalho foi identificar a comunidade infestante de plantas daninhas em áreas de pastagens no município de Nova Olímpia, MT. O levantamento foi realizado nos meses de fevereiro e março de 2012, em que foram analisadas 10 propriedades, tendo cada uma 10 parcelas de 25 m2. Nas parcelas foram realizadas a contagem e identificação das espécies daninhas. Os dados foram analisados por meio de cálculo de densidade, frequência, abundância, densidade relativa, frequência relativa, abundância relativa, índice de valor de importância (IVI) e índice de similaridade. Foram encontradas 31 espécies de plantas daninhas distribuídas em 16 famílias botânicas, sendo, Asteraceae (4), Papilionoideae (4) Poaceae (4) e Malvaceae (3) as mais representativas em números de espécies. As espécies mais ocorrentes foram Sida carpinifolia (IVI = 38,50), Sida spp. (IVI = 36,26), Chenopodium ambrosiodies (IVI = 21,06) e Sida cordifolia (IVI = 19,71). Foi encontrada similaridade expressiva entre as propriedades sendo que as propriedades 6 e 8 se destacaram com índice de similaridade de 78,26%.Item Safety evaluation of the antimicrobial peptide bovicin HC5 orally administered to a murine model(BMC Microbiology, 2013) Paiva, Aline Dias; Fernandes, Kenner Morais; Dias, Roberto Sousa; Rocha, Alípio dos Santos; Oliveira, Leandro Licursi de; Neves, Clóvis Andrade; Paula, Sérgio Oliveira de; Mantovani, Hilário CuquettoBovicin HC5 is an antimicrobial peptide that shows a broad spectrum of activity and potential for biotechnological and therapeutic applications. To gain insight about the safety of bovicin HC5 application, the histological and immunostimulatory effects of orally administrated bovicin HC5 to BALB/c mice were evaluated. BALB/c mice were divided into three groups: negative control (NC group); mice given purified bovicin HC5 (Bov group); mice given ovalbumin (positive control, PC group; a murine model of enteropathy). The mice were initially pre-sensitized, and PBS, bovicin HC5 or ovalbumin were administered for 30 days by daily gavages. Histological and morphometric analysis were performed and the relative expression of cytokines was analyzed by real-time RT-PCR. The oral administration of bovicin HC5 to BALB/c mice reduced weight gain and caused alterations in the small intestine, although absorptive changes have not been detected. The number of total goblet cells and the mucopolysaccharides production were not affected by bovicin HC5 administration. A hypertrophy of Paneth cells and an increase in the number of mitotic cells were observed in Bov group, while the number of mast cells remained unaltered. Increased expression of TNF-α, INF-γ and IL-12 was observed in the small intestine upon bovicin HC5 administration. Bovicin HC5 has only minor effects on intestinal permeability and did not elicit an allergenic response upon oral administration to animal models. Considering the low in vivo toxicity of bovicin HC5, it might be a good candidate for enteral applications.Item Morphological and molecular characterization of Tulasnella spp. fungi isolated from the roots of Epidendrum secundum, a widespread Brazilian orchid(Symbiosis, 2014-02) Pereira, Marlon Corrêa; Coelho, Irene da Silva; Valadares, Rafael Borges da Silva; Oliveira, Sabrina Feliciano; Bocayuva, Melissa; Pereira, Olinto Liparini; Araújo, Elza Fernandes; Kasuya, Maria Catarina MegumiTulasnella spp. are the main fungal symbionts of Brazilian Epidendrum orchids. The taxonomy of these fungi is largely based on ITS rDNA similarity, but culture dependent techniques are still essential to establish the true biological entity of the mycobiont. The aim of this study was to characterize morphologically and molecularly 16 Tulasnella spp. fungi isolated from three different populations of E. secundum and to test the coincidences between morphological and molecular characterization. Two uninucleate rhizoctonia fungi, obtained from Oncidium barbaceniae, and two phytopathogenic isolates were included as outgroups. Qualitative and quantitative morphological characteristics were analyzed using multivariate statistics and were able to distinguish Ceratobasidium, Tulasnella and Thanatephorus genera and separate the isolates of Tulasnella spp. into two groups. Analysis of RAPD (Random Amplified Polymorphic DNA) and ITS rDNA sequences validated the morphological data. Symbionts of O. barbaceniae presented identity to ITS sequences of Ceratobasidium genus, while E. secundum isolates presented identity to two species of Tulasnella. We observed homogeneity among Tulasnella spp. obtained from a single population and from neighboring populations, but there was higher variability among isolates obtained from populations of regions that were farther apart. Morphological data associated with multivariate statistics proved to be a useful tool in the multi-level taxonomy of these orchid-associated fungi and in estimating the diversity of orchid mycorrhizal fungi.Item Endophytic microbial diversity in coffee cherries of Coffea arabica from southeastern Brazil(Canadian Journal of Microbiology, 2013-01-22) Oliveira, Marcelo N. V.; Santos, Thiago M. A.; Vale, Helson M. M.; Delvaux, Júlio C.; Cordero, Alexander P.; Ferreira, Alessandra B.; Miguel, Paulo S. B.; Tótola, Marcos R.; Costa, Maurício D.; Moraes, Célia A.; Moraes, Célia A.The microbiota associated with coffee plants may play a critical role in the final expression of coffee quality. However, the microbial diversity in coffee cherries is still poorly characterized. Here, we investigated the endophytic diversity in cherries of Coffea arabica by using culture-independent approaches to identify the associated microbes, ultimately to better understand their ecology and potential role in determining coffee quality. Group-specific 16S rRNA and 26S rRNA genes polymerase chain reaction – denaturing gradient gel electrophoresis and clone library sequencing showed that the endophytic community is composed of members of the 3 domains of life. Bacterial sequences showing high similarity with cultured and uncultured bacteria belonged to the Betaproteobacteria, Gammaproteobacteria, and Firmicutes phyla. Phylogenetic analyses of cloned sequences from Firmicutes revealed that most sequences fell into 3 major genera: Bacillus, Staphylococcus, and Paenibacillus. Archaeal sequences revealed the presence of operational taxonomic units belonging to Euryarchaeota and Crenarchaeota phyla. Sequences from endophytic yeast were not recovered, but various distinct sequences showing high identity with filamentous fungi were found. There was no obvious correlation between the microbial composition and cultivar or geographic location of the coffee plant. To the best of our knowledge, this is the first report demonstrating internal tissue colonization of plant fruits by members of the Archaea domain. The finding of archaeal small-subunit rRNA in coffee cherries, although not sufficient to indicate their role as active endophytes, certainly expands our perspectives toward considering members of this domain as potential endophytic microbes.