Microbiologia
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11840
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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 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 Agroecological coffee management increases arbuscular mycorrhizal fungi diversity(Plos One, 2019) Prates Júnior, Paulo; Moreira, Bruno Coutinho; Silva, Marliane de Cássia Soares da; Veloso, Tomas Gomes Reis; Stürmer, Sidney Luiz; Fernandes, Raphael Bragança Alves; Mendonça, Eduardo de Sá; Kasuya, Maria Catarina MegumiAgroecology aims to maintain ecosystem services by minimizing the impact of agriculture and promoting the use of biological potential. Arbuscular mycorrhizal fungi (AMF) are elements which are key to improving crop productivity and soil quality. It is pertinent to understand how agricultural management in the tropics affects the AMF spatio-temporal community composition, especially in crops of global importance, such as coffee (Coffea arabica L.). Soil and root samples were collected from three localities under three management systems (agroecological, conventional and forest fragment), during the phenological stages of coffee (flowering, grain filling, harvesting). Spores were extracted for morphological identification and molecular community analysis by PCR–DGGE. Dendrograms were prepared and the bands were sequenced and analyzed by bioinformatics. No differences were observed in the richness of morphospecies between management systems, localities and period, but little is known about tropical species. Molecular analysis showed that the agroecological management system was similar to natural forest and with a higher diversity indices than conventional management. Locality and period of sample affect AMF community composition. It is necessary to associate classical taxonomic evaluations with molecular biological techniques because different approaches can lead to different outcomes. This study contributes to the understanding of the impact of agriculture management systems on AMF and provides evidence that agroecology is a management system applicable to sustainable coffee production.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 Arbuscular mycorrhizal fungi (Glomeromycota) communities in tropical savannas of Roraima, Brazil(Mycological Progress, 2018-08-13) Kemmelmeier, Karl; Stürmer, Sidney Luiz; Moreira, Bruno Coutinho; Kasuya, Maria Catarina Megumi; Pereira, Gilmara Maria Duarte; Silva, Krisle daSavanna vegetation in the northern region of Brazil is jeopardized by several anthropogenic activities including cattle ranching and extensive agriculture, and soil biota of these ecosystems is virtually unknown. The soils in savannas are poor in nutrients, very acidic, and subject to drought, and under these conditions, arbuscular mycorrhizal fungi (AMF) are likely to play a key role on plant nutrition and improving soil structure. In this study, we surveyed AMF communities in five savanna locations in Roraima state, Northern Brazil. AMF species were identified using two approaches: field collected spores and trap cultures. Twenty-three AMF species were identified, including 21 species in field samples, 8 species in trap cultures, of which 15 and 2 were unique to field and trap culture samples, respectively. Gigaspora margarita, Dentiscutata heterogama, and Glomus sp1 were the most frequent species recovered from all locations. AMF communities were dominated by members of Gigasporaceae that accounted for 50 to 87% of the total species richness within each location. Spore numbers differed across locations and ranged from 5 to 25 spores 100 cm−3 soil. Redundancy analysis indicated that soil organic matter was the only selected predictor among soil parameters and correlated positively with occurrence of Glomus heterosporum. We conclude that savannas in Roraima harbor a high sporulating AMF species richness with communities dominated by members of Gigasporaceae and that organic carbon is an important edaphic factor influencing AMF community composition in this ecosystem.
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