Microbiologia
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11840
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Resultados da Pesquisa
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 Expression of the nifH gene in diazotrophic bacteria in Eucalyptus urograndis plantations(Canadian Journal of Forest Research, 2016-02) Silva, Marliane de Cássia Soares da; Mendes, Igor Rodrigues; Paula, Thiago de Almeida; Dias, Roberto Sousa; Paula, Sérgio Oliveira de; Silva, Cynthia Canedo; Bazzolli, Denise Mara Soares; Kasuya, Maria Catarina MegumiA large proportion of eucalypt plantations in Brazil are located in areas with low soil fertility. The actions of microorganisms are of great importance for the cycling of nutrients, including nitrogen (N), that are essential for plant metabolism. Denaturing gradient gel electrophoresis (DGGE) was used to monitor and identify the total and active microorganisms involved in the N cycle in both the soil and root systems of a forest of Eucalyptus urograndis with sections that were fertilized with N or unfertilized. Quantitative real-time PCR was used to examine the expression of the nifH gene in N-fixing bacteria present in both the soil and root systems. According to the DGGE analysis, in the total and active populations of N-fixing bacteria, the presence and expression of the nifH gene were influenced by the winter and summer seasons and (or) N fertilization, respectively. DGGE band sequencing from total DNA samples showed that the most abundant group of diazotrophic bacteria belonged to Alphaproteobacteria in both the soil and root systems. Quantitative real-time PCR revealed that nifH expression was higher in the soil samples, especially in those that did not receive N fertilization. The differences in the composition of the total and active diazotrophic populations highlight the importance of evaluating the active populations, because they are effectively responsible for the biogeochemical transformation of N and also control its' availability to plants.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 Morphological and molecular characterization of mycorrhizal fungi isolated from neotropical orchids in Brazil(Canadian Journal of Botany, 2005-01) Pereira, Olinto Liparini; Kasuya, Maria Catarina Megumi; Borges, Arnaldo Chaer; Araújo, Elza Fernandes deTo initiate a conservation program of the Orchidaceae from the Brazilian Atlantic rain forest with the purpose of ex situ conservation or reintroduction in the State of Minas Gerais, seven mycorrhizal Rhizoctonia-like fungal strains were isolated from roots of seven neotropical orchid species from three different Atlantic rain forest fragments. Taxonomic studies revealed that the isolates belong to the genera Ceratorhiza and Epulorhiza. The Epulorhiza isolates were identified as Epulorhiza repens (N. Bernard) R.T. Moore and Epulorhiza epiphytica Pereira, Rollemberg et Kasuya. RAPD analysis indicated higher polymorphism between Epulorhiza epiphytica and Epulorhiza repens than found in the PCR RFLP analysis. RAPD and morphological analyses indicated a degree of relatedness among the Ceratorhiza isolates obtained from the roots of different Oncidium species. A combination of morphological and molecular characterizations permitted integration of fungal strain identification with genetic relatedness among the isolates, thus allowing some inferences to be made on specificity of these endosymbionts under field conditions.Key words: biodiversity, Ceratorhiza, Epulorhiza, orchid mycorrhiza, Rhizoctonia-like, symbiosis, specificity.Item Occurrence and types of ectomycorrhizae present in seedlings of Picea glehnii in a natural forest in Hokkaido(Mycoscience, 1995-10) Kasuya, Maria Catarina Megumi; Igarashi, Tsuneo; Masato ShibuyaPicea glehnii seedlings whose ages ranged from 2 to 5 years and which were growing in aP. glehnii-Abies sachalinensis natural forest where the surface had been scarified 6 years before, were assessed for the occurrence and types of ectomycorrhizae. Based on the macro- and microscopic characteristics, 34 types of ectomycorrhizae were classified. The basidiomycetes were clearly dominant and it was common to observe more than one type of mycorrhiza occurring in the same root tip. The diversity of mycorrhizal types and the presence of at least one type of ectomycorrhiza in a single seedling, observed in this work, indicate a very dynamic system of mycorrhizal formation inP. glehnii seedlings, which allows them to survive and grow in a forest surface subjected to soil scarification.Item Production of edible mushroom and degradation of antinutritional factors in jatropha biodiesel residues(LWT - Food Science and Technology, 2013-03) Luz, José Maria Rodrigues da; Paes, Sirlaine Albino; Torres, Denise Pereira; Nunes, Mateus Dias; Silva, Juliana Soares da; Mantovani, Hilário Cuquetto; Kasuya, Maria Catarina MegumiThe elimination of antinutritional factors of the Jatropha curcas L. seed cake is important for decreasing environmental damage and adding economic value to this residue of the biodiesel industry. In this study, we analyzed the ability of Pleurotus ostreatus to degrade antinutritional factors and produce edible mushrooms using different proportions of the J. curcas seed cake as substrate. After 60 d of incubation at 25 °C, we observed 95% phytic acid and 85% tannins reductions, and high mushrooms productivity. There was no evidence of tannins or phytic acid in these mushrooms. Furthermore, the phorbol ester concentration observed in these mushrooms was around 1000-fold lower than that found in the non-toxic variety of J. curcas. Thus, P. ostreatus can degrade the antinutritional factors found in J. curcas seed cake. The jatropha seed cake can potentially be used for mushroom production, with high nutritional value, and animal ration, after treated by P. ostreatus, adding economic value to the biodiesel residue and avoiding inadequate disposal in the environment.Item Effect of inoculation of symbiotic fungi on the growth and antioxidant enzymes’ activities in the presence of Fusarium subglutinans f. sp. ananas in pineapple plantlets(Acta Physiologiae Plantarum, 2016-09-06) Moreira, Bruno Coutinho; Prates Junior, Paulo; Jordão, Thuany Cerqueira; Silva, Marliane de Cássia Soares da; Stürmer, Sidney Luiz; Salomão, Luiz Carlos Chamhum; Otoni, Wagner Campos; Kasuya, Maria Catarina MegumiThe inoculation with symbiotic fungi, Arbuscular mycorrhizal fungi (AMF) and/or Piriformospora indica on the growth, nutrient absorption, and induction of antioxidant enzyme activities in plantlets of pineapple ‘Imperial’ (fusariosis-resistant) and ‘Pérola’ (fusariosis-susceptible) in the presence of Fusarium subglutinans f. sp. ananas was investigated. The experiment was comprised by two cultivars, with or without fungal inoculation (Claroideoglomus etunicatum, Rhizophagus clarus, and P. indica, a mixture of all the fungi, and the control—absence of fungal inoculation), with or without applying Fusarium conidia, and with four replicates. In both cultivars, nutrient absorption was higher in the AMF plantlets compared to those inoculated with P. indica or the control ones, although it was more efficient in ‘Imperial’ than in ‘Pérola’. Inoculation with AMF and/or P. indica as well as the pathogen influenced differently the activities of superoxide dismutase, catalase, glutathione reductase, peroxidase, and polyphenol oxidase, in the shoots or roots of pineapple plantlets in both cultivars. Inoculated plantlets with mixture of all the fungi also exhibited a better growth and nutrient absorption, and generally, the ‘Imperial’ responded better than ‘Pérola’. In addition, these plantlets developed better than the control even in the presence of pathogen, indicating that inoculation with AMF and/or P. indica may contribute to the production of more resistant propagative material. Increased antioxidant enzyme activity is a potential strategy for managing this plant for explore biological control as an alternative to reduce environmental and health impacts by reducing the use of fungicides.Item Arbuscular mycorrhizal fungal diversity in rhizosphere spores versus roots of an endangered endemic tree from Argentina: Is fungal diversity similar among forest disturbance types?(Applied Soil Ecology, 2016-02) Soteras, Florencia; Moreira, Bruno Coutinho; Grilli, Gabriel; Pastor, Nicolás; Mendes, Flávia Carneiro; Mendes, Daniele Ruela; Renison, Daniel; Kasuya, Maria Catarina Megumi; Souza, Francisco Adriano de; Becerra, AlejandraThe aim of this study was to compare the arbuscular mycorrhizal fungal (AMF) community of the rhizosphere and inside the roots of the perennial Polylepis australis tree. Three forest types differing in their structural complexity due to anthropogenic disturbances were chosen at three different sites at the high mountains of central Argentina. Rhizosphere spores and P. australis roots of four randomly selected trees were isolated from 36 soil samples, DNA was extracted and the 18S rDNA fragments were amplified by nested-PCR. The products were analyzed by DGGE and the bands were excised for sequencing. In total, 36 OTUs were defined from 56 DGGE bands successfully sequenced. Forest disturbance types showed similar communities of AMF, as rhizosphere spores and within the roots of P. australis. However, DGGE lustering showed mainly differences between rhizosphere spores and root-colonizing AMF. Members of Glomeraceae, Pacisporaceae, Acaulosporaceae and Gigasporaceae were shown in rhizosphere spore samples. Root samples showed only members of Acaulosporaceae and Gigasporaceae, which might be complementary in terms of soil resources exploration. The prevalence of the root system with their community of symbionts might explain the resilience of AMF soil communities to forests structural changes. This study presents evidence of a possible preference in the AMF–P. australis interaction.Item Enzymatic extract containing lignin peroxidase immobilized on carbon nanotubes: Potential biocatalyst in dye decolourization(Saudi Journal of Biological Sciences, 2016-02-11) Oliveira, Sabrina Feliciano; Luz, José Maria Rodrigues da; Kasuya, Maria Catarina Megumi; Ladeira, Luiz Orlando; Correa Junior, AryThe majority of the textile dyes are harmful to the environment and potentially carcinogenic. Among strategies for their exclusion, the treatment of dye contaminated wastewater with fungal extract, containing lignin peroxidase (LiP), may be useful. Two fungi isolates, Pleurotus ostreatus (PLO9) and Ganoderma lucidum (GRM117), produced the enzymatic extract by fermentation in the lignocellulosic residue, Jatropha curcas seed cake. The extracts from PLO9 and GRM117 were immobilized on carbon nanotubes and showed an increase of 18 and 27-fold of LiP specific activity compared to the free enzyme. Also, LiP from both fungi extracts showed higher Vmax and lower Km values. Only the immobilized extracts could be efficiently reused in the dye decolourization, contrary, the carbon nanotubes became saturated and they should be discarded over time. This device may offer a final biocatalyst with higher catalytic efficiency and capability to be reused in the dye decolourization process.
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