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Registros recuperados: 23 | |
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Terumi Sanomiya,Luciana; Carlos Assis,Luis; Ademir de Oliveira,João; Nahas,Ely. |
La celulosa es el compuesto orgánico vegetal más abundante, derivándose principalmente de los residuos de la planta. La descomposición de la paja de caña de azúcar (Saccharum officinarum L.) fue estudiada en un período de hasta 90 días a través de variables relacionadas con el ciclo del carbono, como la actividad respiratoria y las actividades de la CM-celulasa (CM, celulosa microcristalina) y de la CMC-celulasa (CMC, carboximetilcelulosa). Los tratamientos consistieron en la adición de 0; 0,5 y 1,0% de paja, en la presencia y ausencia de viñaza (residuo de las destilerías de producción de alcohol de caña de azúcar) y fertilizante nitrogenado. Las actividades respiratoria y de las celulasas aumentaron hasta el día 14 de incubación y después disminuyeron.... |
Tipo: Journal article |
Palavras-chave: Paja de caña de azúcar; Actividad respiratoria; CM-celulasa; CMC-celulasa; Mineralización. |
Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0365-28072006000100010 |
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Nahas,Ely. |
Considerando-se que uma forma de prover fosfato disponível para as plantas é através da atividade mineralizadora microbiana do fósforo orgânico, avaliou-se a influência da planta (braquiária, guandu e sem planta), dos fertilizantes (superfosfato simples, fosfato de rocha e sem adubo) e da calagem (com e sem calcário) nas populações de microrganismos produtores de fosfatases ácida e alcalina. Do total de bactérias, 70,6% apresentaram atividade de fosfatase alcalina e 58,2% de fosfatase ácida e dos fungos, 64,3% e 84,7% respectivamente. Esses dados mostram número significativo de microrganismos com habilidade de mineralização do fósforo orgânico. Observou-se efeito restritivo do guandu sobre as bactérias e fungos produtores de fosfatases alcalina e ácida,... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bactérias; Fungos; Fosfatase ácida; Fosfatase alcalina; Fosfato de rocha; Superfosfato; Braquiária; Guandu; Calagem. |
Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052002000300008 |
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Barroso,Cinthya Babá; Nahas,Ely. |
The present study deals with the effect of increased concentrations of alcohols (methanol and ethanol) on the solubilization of FePO4 and CaHPO4 by Aspergillus niger. The efficiency of solubilization (ES) of inorganic phosphates, fungal growth, acid production and pH variation were determined. The concentrations of alcohols that most favored the solubilization of phosphates were 4% methanol and 3% ethanol. The ES of phosphates by the fungus in media containing methanol ranged from 11-96% and 0.4-87% for ethanol. The stimulation or inhibition of solubilization was dependent on greater or lesser fungus growth, acid production and decreased pH. These responses were supported by the correlation between the amount of phosphate dissolved and fungal growth... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ethanol; Methanol; Growth; Acid production; Phosphate solubilization. |
Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132013000200003 |
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Nahas,Ely. |
ABSTRACTThis work studied the acid phosphatase (APase) activity from culture medium (extracellular, eAPase) and mycelial extract (intracellular, iAPase) ofAspergillus niger F111. The influence of fungus growth and phosphate concentration of the media on the synthesis and secretion of phosphatase was demonstrated. The effects of pH, substrate concentration and inorganic and organic compounds added to the reaction mixture on APase activity were also studied. Both enzymes were repressed by high concentrations of phosphate. Overexpression of iAPase in relation to eAPase was detected; iAPase activity was 46.1 times higher than eAPase. The maximal activity of eAPase was after 24h of fungus growth and for iAPase was after 96h. Optimal pH and substrate... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Enzyme inhibitors; Molybdenum; Overexpression; Phosphate; Soil chemical characteristics. |
Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132015000500658 |
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Barroso,Cinthya Babá; Pereira,Gener Tadeu; Nahas,Ely. |
The solubilization of inorganic phosphates by microorganisms supplies phosphates for plant nutrition and increases their growth. The solubilization of CaHPO4 (Ca-P) and AlPO4 (Al-P) by Aspergillus niger using several carbon and nitrogen sources was studied. Solubilization of Ca-P was enhanced when the carbon sources were mannitol, maltose, galactose and glucose (in that order). Galactose, sucrose and maltose were the carbon sources that enhanced the solubilization of Al-P. More extensive growth, acid production, and decrease in pH were obtained in the Al-P medium than in the Ca-P medium, however, the quantity of solubilized phosphate was 12% less. Phosphate solubilization was related to acid production, pH drop and fungal growth in the culture medium. The... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Nutrition; Phosphorus; Phosphate source; Phosphate solubilization; Titratable acidity. |
Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822006000400006 |
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Nemoto,Marta Cecília Mallasen; Nahas,Ely; Pitelli,Robinson Antonio; Coelho,Lisias. |
Bipolaris euphorbiae Muchovej & Carvalho can be combined with herbicide in order to control a large spectrum of weed species, being a strong candidate for the biocontrol of Euphorbia heterophylla L. (milk weed). The fungus release can be combined with herbicide in order to control a broader spectrum of weed species. Thus, laboratory experiments were set up to study the feasibility of using tank mixes of B. euphorbiae spores with herbicides or surfactants recommended for soybean. Mycelial growth and conidia germination were evaluated in PDA medium enriched with the herbicides oxasulfuron (80 g/ha), glyphosate (4 L/ha), bentazon (1.5 L/ha), fomesafen (1 L/ha), chlorimuron-ethyl (80 g/ha), lactofen (1 L/ha) and imazetaphyr (1 L/ha), and the... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bipolaris euphorbiae; Mycelial growth; Conidia germination; Herbicides; Surfactants. |
Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822002000400015 |
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Silva,Paulo da; Nahas,Ely. |
The diversity of bacterial isolates from soil in response to different plants (control, Brachiaria ruziziensis and Cajanus cajan), fertilization (control, simple superphosphate and rock phosphate) and liming (with and without lime) was evaluated. Phenotypic and physiological characteristics of the isolates were recorded and organized in a file to identify the bacteria. Among the isolates, 95% were Gram-positive and 5% Gram-negative rods. Soil cultivated with B. ruziziensis favored the nonsporing Gram-positive and Gram-negative rods compared to soils with C. cajan or uncultivated. Number of spore-forming Gram-positive rods were higher in plots with superphosphate than in unfertilized soil or soil fertilized with rock phosphate. In unfertilized plots, larger... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bacteria; Phosphate; Brachiaria ruziziensis; Cajanus cajan; Liming. |
Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822002000400005 |
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Gréggio,Thiago Claudino; Assis,Luiz Carlos; Nahas,Ely. |
The decomposition of soil litter contributes to maintaining agricultural sustainability, since the nutrients released by microbial activity are determinants of the net productivity of the agroecosystem. The decomposition of rubber tree (Hevea brasiliensis [Willd. ex A. Juss.] Müll. Arg.) leaves located on the surface and buried in at 10 cm depth in Forest and Savannah (Cerradão) soils (Oxisols) was studied, with emphasis on the production of CO2 and the monthly variation of the remaining amounts of litter mass, soluble substances, cellulose and lignin. To evaluate CO2 production, H. brasiliensis leaves were incubated for 30 days in soils from the 0-2 cm and 10-12 cm layers. CO2 production increased in the 0-2 cm layer in comparison to the 10-12 cm layer.... |
Tipo: Journal article |
Palavras-chave: Litter mass; Cellulose; Lignin; Soluble substances; Litter-bags. |
Ano: 2008 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392008000200002 |
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Pinto,Cristiane Rêgo Oliveira; Nahas,Ely. |
O objetivo deste trabalho foi determinar as populações microbianas e suas atividades envolvidas no ciclo do S, de solos virgem e cultivado, e as suas relações com as diferentes frações de S no solo. Das populações de microrganismos pesquisados, apenas foram encontradas as bactérias autótrofas oxidantes de S0 em pH 5,0 e as heterótrofas oxidantes de tiossulfato, que representaram menos de 0,1% das bactérias totais. A média das bactérias autótrofas foi o dobro das heterótrofas. As maiores contagens de bactérias totais, autótrofas e heterótrofas foram encontradas nos solos com milho, de pastagem e de floresta integrada, respectivamente. A atividade da arilsulfatase foi maior em solo de floresta integrada e a da rodanase em solo de pastagem. A arilsulfatase... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bactéria; Oxidação; Arilsulfatase; Rodanase. |
Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2002001200011 |
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Cordeiro,Meire Aparecida Silvestrini; Corá,José Eduardo; Nahas,Ely. |
Sistemas autossustentáveis favorecem as populações microbianas devido à conservação e ao aumento da matéria orgânica no solo. Além disso, as plantas que fazem parte desses sistemas promovem o efeito rizosférico, por meio da zona de influência das raízes, que resulta no aumento da atividade e na modificação da população microbiana. O objetivo deste trabalho foi avaliar o efeito da rotação de culturas de inverno sobre sequências de verão, em sistema de semeadura direta, nos atributos bioquímicos (amilase, urease, celulase e protease) e químicos (carbono orgânico total - COT, carboidratos totais e proteínas totais) em solo rizosférico (SR) e não rizosférico (SNR). Este estudo foi constituído de três culturas de inverno: milho (Zea mays L.), girassol... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Enzimas do solo; Efeito rizosférico; Atividade microbiana. |
Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832012000600013 |
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Garcia,Martha Regina Lucizano; Nahas,Ely. |
Os efeitos da lotação de animais na produção de ovinos têm sido bastante estudados. No entanto, informações sobre seus efeitos na biomassa e nas atividades microbianas e, em conseqüência, na fertilidade do solo de pastagens são escassas. Neste trabalho, os efeitos da lotação de ovinos (LO) na biomassa e nas atividades microbianas responsáveis pela transformação dos compostos do C e N em solo de clima subtropical foram avaliados. As amostras de solo foram coletadas nas camadas de 0-10 e 10-20 cm de pastos com baixa LO (5 animais ha-1), alta LO (40-50 animais ha-1) e com ausência de animais, em um delineamento inteiramente casualizado em parcelas subdivididas, com seis repetições. Os maiores valores de biomassa microbiana e das atividades respiratória,... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Atividade biológica; CO2; Enzimas; Matéria orgânica. |
Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832007000200009 |
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Pupin,Breno; Freddi,Onã da Silva; Nahas,Ely. |
Compaction is one of the most destructive factors of soil quality, however the effects on the microbial community and enzyme activity have not been investigated in detail so far. The objective of this study was to evaluate the effects of soil compaction caused by the traffic of agricultural machines on the soil microbial community and its enzyme activity. Six compaction levels were induced by tractors with different weights driving over a Eutrustox soil and the final density was measured. Soil samples were collected after corn from the layers 0-0.10 and 0.10-0.20 m. The compaction effect on all studied properties was evident. Total bacteria counts were reduced significantly (by 22-30 %) and by 38-41 % of nitrifying bacteria in the soil with highest bulk... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Microorganisms; Enzymes; Corn. |
Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832009000500014 |
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Buzinaro,Thais Nucci; Barbosa,José Carlos; Nahas,Ely. |
Adubos verdes (AVs) são condicionadores do solo utilizados para a melhoria da estrutura e fertilidade do solo. Este estudo avaliou o efeito de Crotalaria spectabilis Roth (crotalária), Cajanus cajan (L) Millsp (guandu) e Brachiaria decumbens Stapf (braquiária) nas propriedades microbiológicas e bioquímicas do solo sob laranjal. As leguminosas foram plantadas nas entrelinhas do laranjal e, após 3 meses, cortadas e lançadas nas entrelinhas. A braquiária, já estabelecida, foi roçada e lançada nas entrelinhas. Após 5 meses, as amostras de solo foram coletadas na entrelinha e na linha, na profundidade de 0-20 cm. O delineamento experimental foi em parcela subdividida. Efeito significativo (p< 0,05%) da aplicação dos AV sobre as contagens de bactérias, as... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Desidrogenase; Urease; Atividade nitrificante; Solubilização. |
Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452009000200014 |
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Garcia,Martha Regina Lucizano; Sampaio,Alexandre Amstalden Moraes; Nahas,Ely. |
The objective of this work was to study the effect of grazing systems: rotational, continuous and the absence of cattle, in pastures of Brachiaria brizantha on microbial activity (respiratory, potential nitrification, solubilizing, and enzymatic) and on the chemical attributes (contents of organic carbon, total nitrogen, organic phosphorus, and moisture) of Eutrustox soil over one year. Eight Canchim breed animals were used. The samples were collected in the four seasons from 2005 to 2006. The average of organic C, organic P, and moisture contents, as well as potential nitrification and solubilizing activity and urease and acid phosphatase activities were significantly higher in the spring and/or summer than in autumn and/or winter. The total nitrogen... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cellulase; Microbial respiratory activity; Phosphatase; Potential nitrification; Urease. |
Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982011000700024 |
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Vieira,Francisco Cleber Sousa; Nahas,Ely. |
The number of colony forming units (CFU) of different groups of bacteria and fungi in samples stored at temperatures of 5 to -12oC for 0-32 weeks was evaluated. The number of CFU obtained after the different periods of storage of red latossol soil was compared with the number of colonies obtained immediately after removal of soil samples (time zero). The number of total bacteria and actinomycetes in the samples remained practically unchanged throughout the storage period. The number of Gram-negative bacteria decreased by as much as 69% compared to control, while the number of Bacillus spp and of fungi increased 1.9 to 4.9 times starting from the 12th week in samples stored at 5oC. Except for the variations observed in fungal counts, the remaining groups of... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bacteria; Fungi; Phosphatase; Soil storage. |
Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37141998000300001 |
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Registros recuperados: 23 | |
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