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Search Results: 1 - 10 of 76817 matches for " Maria Catarina Megumi;Barros "
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Diversidade de fungos micorrízicos Epulorhiza spp. isolados de Epidendrum secundum (Orchidaceae)
Pereira, Marlon Corrêa;Pereira, Olinto Liparini;Costa, Maurício Dutra;Rocha, Rodrigo Barros;Kasuya, Maria Catarina Megumi;
Revista Brasileira de Ciência do Solo , 2009, DOI: 10.1590/S0100-06832009000500012
Abstract: rhizoctonia-like mycorrhizal fungi epulorhiza spp. have been isolated from orchids of the genus epidendrum and have been used to promote the symbiotic germination of orchid seeds. epidendrum secundum is a widely distributed orchid in campo de altitude (high elevation grassy vegetation) regions of the state park of serra do brigadeiro (pesb), minas gerais, brazil, and little is known about the mycorrhizal relationships of this species in the park. the objective of this study was to evaluate the morphological diversity of rhizoctonialike mycorrhizal fungi isolated from four e. secundum populations growing in three regions of a campo de altitude, in the region of totem deitado mountain, pesb. twenty-six fungal isolates were obtained, all belonging to epulorhiza. the quantitative and qualitative morphological characteristics revealed, in general, low variability among the fungi isolated from the same orchid population and among isolates from the same region, but high variability among the fungi isolated from the populations from different regions. based on these morphological characteristics, the isolates were separated into four groups. the first consisted of the fungi from populations i and ii from region a, the second of isolates from population iii from region b, the third of isolate m61 from population ii from region c, and the fourth of a single isolate obtained from population iv from region c. the morphological variability observed indicates the existence of diversity of epulorhiza spp. associated with e. secundum in pesb.
Impacto do monocultivo de café sobre os indicadores biológicos do solo na zona da mata mineira
Nunes, Luís Alfredo Pinheiro Leal;Dias, Luiz Eduardo;Jucksch, Ivo;Barros, Nairam Félix;Kasuya, Maria Catarina Megumi;Correia, Maria Elizabeth Fernandes;
Ciência Rural , 2009, DOI: 10.1590/S0103-84782009005000216
Abstract: this study aimed to evaluate the effect of the coffee monoculture in an oxisol of the zona da mata (mg, brazil) through changes in total organic carbon in the soil and microbiological indicators of soil quality. four areas were selected: a) culture of coffee (novo mundo) during 22 years (c22); b) culture of coffee (catuaí) during 16 years (c16) c) secondary forest with approximately 30 years old (m30) and d) secondary forest during 40 years (m40). soil samples were collected in the depth of 0-10cm in january, april, july and october. the biological variables studied were sensitive to characterize changes in soil quality from coffee monoculture. the results varied with the season and climate. in the driest period, a reduction in the values occurred, affecting more drastically the coffee systems. the index of soil quality showed that the c22 system presented greater loss of quality in relation to the m40, indicating less sustainability commitment.
Isolamento e sele??o de fungos causadores da podrid?o-branca da madeira em florestas de Eucalyptus spp. com potencial de degrada??o de cepas e raízes
Alonso, Sandra Kunieda de;Silva, Aderlan Gomes da;Kasuya, Maria Catarina Megumi;Barros, Nairam Félix de;Cavallazzi, José Renato Pereira;Bettucci, Lina;Lupo, Sandra;Alfenas, Acelino Couto;
Revista árvore , 2007, DOI: 10.1590/S0100-67622007000100016
Abstract: the aim of this work was to isolate native wood white-rot fungi from fungal fruit-bodies and eucalyptus wood fragments from different regions of brazil and to test their potential for degrading dead stumps and roots in eucalyptus plantings after harvest. fungi isolates were obtained in a culture medium composed by eucalyptus sawdust and agar. among 292 isolates submitted to the banvedamm test, 144 were classified as phenoloxidases producing isolates. among nine c/n ratios tested, it was observed a tendency of occurring larger chip decay in the c/n ratios equal to 60 : 1, 200 : 1 and 300 : 1. two decay assays were performed in wood chips of eucalyptus saligna using the c/n ratio 60 : 1 in order to verify which isolates were able to cause larger reduction of dry matter. in the first assay, which was evaluated at 90 days of incubation, seven isolates that stood out in relation to trametes versicolor were selected. the second assay evaluated the capacity of 46 isolates in promoting decay. the isolates selected in the first assay were among the 11 most efficient in the second assay. based on dna analysis, six isolates were identified as pycnoporus sanguineus (3 isolates), peniophora sp., pestalotiopsis sp. e ganoderma sp.
Mycelial Growth of Pleurotus Spp in Se-Enriched Culture Media  [PDF]
Marliane de Cássia Soares da Silva, Mateus Dias Nunes, Jose Maria Rodrigues da Luz, Maria Catarina Megumi Kasuya
Advances in Microbiology (AiM) , 2013, DOI: 10.4236/aim.2013.38A003

Selenium (Se) is an essential element to human. However, this element can be in low content in soil of some regions. Se deficiency may cause Keshan disease, thyroid dysfunction and osteoarthritis. The Se-enriched cereals are an interesting way to prevent these diseases. But, recent studies have shown that Se-enriched mushrooms are a better Se source. This occurs due to the high capacity of the fungi to absorb and transform the inorganic Se to organic forms, which are more bioavailable. Pleurotus ostreatus and Pleurotus eryngii are mushrooms species worldwide consumed and able to Se bioaccumulate. However, depending on the level of this element, it can be toxic for the fungus. Here we showed that the presence of the Se in culture medium decreases fungal growth rate, hyphae diameter and septum distance and causes alteration in color of colony. A garlic strong smell was directly proportional to Se level. P. eryngii was more tolerant to Se than P. ostreatus. So, it is important to screen this element level for Se-enriched mushroom production.

BIOTROPIA : the Southeast Asian Journal of Tropical Biology , 1996,
Abstract: This work sought to verify the presence of compounds with antimicrobial properties in extracts of ectomycorrhizal fungi or in Picea glehnii inoculated with ectomycorrhizal fungi. Extracts from Pisolithus tinctorius, Scleroderma flavidum, Amanita pantherina and Paxillus sp., grown in liquid culture media, and from P. glehnii seedlings inoculated or not with the above ectomycorrhizal fungi and cultivated in in vitro condition, were processed to obtain two fractions, water and ethyl acetate solubles. These fractions were tested for the presence of inhibitory constituents against Fusarium roseum, Pythium sp. and Rhizoctonia solani. Direct bioautography technique on TLC or paper disc technique was used, depending on the extract and pathogenic fungi tested. The results showed the production on inhibitory components, not only by ectomycorrhizal fungi, but also by P. glehnii inoculated or not with ectomycorrhizal fungi. The sensitivity varied considerably according to the type of fungus or extract.
Regulation of Respiratory and Ligninolytic Enzyme Activity of Lentinula edodes by Selenium  [PDF]
Regiane Gon?alves Feitosa Leal Nunes, Jose Maria Rodrigues da Luz, Elizabete Fantuzzi, Maria Catarina Megumi Kasuya, Maria Cristina Dantas Vanetti
Advances in Microbiology (AiM) , 2013, DOI: 10.4236/aim.2013.38A006

The production of mushrooms enriched with essential elements, e.g. selenium, for human health is an interesting strategy to improve the functional foods supply. The selenium is an essential mineral and makes part of structure of enzymes involved in the oxidative metabolism. However, the selenium effect on the activity of respiratory and lignocellulolytic enzymes has not been considered. The understanding of this effect is important to determine the selenium concentration that increases the mushroom productivity and the degradation rate of the substrate. In this study, it was observed reduction of the respiratory activity of Lentinula edodes (Berk.) Pegler, the shiitake mushroom, in function of the increasing of the sodium selenite concentration in the substrate (p < 0.05). Selenium did not inhibit the activity of the hydrolytic enzymes (cellulase and xylanase), but it increased the activity of the oxidative enzyme (laccase). Respiratory activity of L. edodes has a negative correlation with sodium selenite concentration added in substrate. Thus is important to define the ideal dose of selenium to be added to the substrate for increasing lignocellulosic residues degradation and, consequently, guarantee a higher production of Se-enriched mushrooms.

Growth and antibacterial activity of Lentinula edodes in liquid media supplemented with agricultural wastes
Hiroko Hassegawa,Regina; Megumi Kasuya,Maria Catarina; Dantas Vanetti,Maria Cristina;
Electronic Journal of Biotechnology , 2005,
Abstract: antibacterial activity of lentinula edodes against bacillus subtilis was evaluated in cell-free filtrates obtained after growth in 14 different culture media. the highest b. subtilis growth inhibition was promoted by filtrates of growth media supplemented with rice bran, vermiculite or molasses. l. edodes dry mycelial biomass in liquid culture with 0.5% added rice bran was 3.2 mg/ml, after growth for 30 days at 25oc without shaking, and 4.3 mg/ml under orbital shaking (150 rpm). however, antibacterial activity, detected between 20 and 24 days of incubation of stationary cultures, was absent in filtrates of aerated cultures. temperatures of 20-25oc enhanced both growth and antibacterial activity. optimum ph for l. edodes mycelial growth was 3.0-3.5, while for production of antibacterial substance(s) it was 4.5. our results indicated that incubation conditions that enhance mycelial growth are quite different from those necessary for production of antibacterial substance(s) by l. edodes
Antimicrobial activity and mineral composition of shiitake mushrooms cultivated on agricultural waste
Casaril, Kérley Braga Pereira Bento;Kasuya, Maria Catarina Megumi;Vanetti, Maria Cristina Dantas;
Brazilian Archives of Biology and Technology , 2011, DOI: 10.1590/S1516-89132011000500017
Abstract: the 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 composition.
Laccase production by Lepista sordida
Cavallazzi, José Renato Pereira;Oliveira, Maria Goreti de Almeida;Kasuya, Maria Catarina Megumi;
Brazilian Journal of Microbiology , 2004, DOI: 10.1590/S1517-83822004000200016
Abstract: a lepista sordida laccase has been characterized. laccase and manganese peroxidase were detected in liquid medium with ammonium phosphate, yeast extract and ammonium molybdidate as nitrogen sources after 3 days of cultivation. laccase optimal temperature and ph were 45oc and 3.5, respectively.
Ishikawa, Noemia Kazue;Kasuya, Maria Catarina Megumi;Vanetti, Maria Cristina Dantas;
Brazilian Journal of Microbiology , 2001, DOI: 10.1590/S1517-83822001000300008
Abstract: the antibacterial activity of 35 isolates of lentinula edodes, a shiitake mushroom, against bacillus subtilis was evaluated by diffusion technique in agar with a semi-solid overlay. all isolates inhibited b. subtilis and the isolate le1 promoted the formation of the largest inhibition zone. l. edodes le1 also presented antibacterial activity against foodborne pathogens and food contaminant bacteria, particularly gram-positive species. the antibacterial activity of the culture filtrate after 18-25 days of cultivation of l. edodes in broth at 25oc was high. the inhibitory activity was observed only in the organic layer when the culture filtrate was partitioned between ethyl acetate and water, suggesting that the inhibitory substances have low polarity. the silica gel thin-layer zone at rf values of 0.63-0.80, developed in chloroform - acetone - ethyl acetate - methanol = 40:5:5:2, was responsible for the antibacterial activity against b. subtilis. the inhibitory activity of l. edodes was detectable in the culture filtrate after heat treatment at 100oc for 10 min and after storage at 4oc for 120 days.
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