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Search Results: 1 - 10 of 7817 matches for " microbial metabolic groups "
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Grupos metabólicos microbianos de la laguna Mar Chiquita (Córdoba, Argentina) y su implicancia en el ciclado de nutrientes
Abril,Adriana; Noe,Laura; Merlo,Carolina;
Ecolog?-a austral , 2010,
Abstract: the microbial populations of saline environments are physiologically adapted to extreme conditions of salinity and oxygen shortage, and are major responsibles of chemical element returns to the atmosphere in salt water ecosystems. the mar chiquita lake, an extensive saline lake of the province of córdoba, argentina (provincial reserve and ramsar site), has been scarcely explored, particularly in its microbiological aspects. here we present a first approach to the knowledge of its microbial communities and other environmental parameters. we collected water and sediment samples from the coast and open waters of different depth, and evaluated chemical and physical parameters and abundance of microbial metabolic groups involved in the degradation of organic compounds and nutrient release. the results showed an abundant bacterial community constituted by heterotrophic microorganisms with aerobic respiration and fermentation, and by amonifiers, nitrate-reducers, nitrogen fixers, hydrogen sulphide-oxidisers, sulfate-reducers, and iron-oxidisers. the ammonium-oxidisers were less abundant. the abundance of different metabolic groups responded to factors associated with oxygen availability and both allochthonous and autochthonous organic carbon availability. similarly to other saline lakes of the world, our results suggest that in this lake: (1) sulfate reduction would be the most important metabolism, (2) the presence of aerobic organisms in high salinity environments would respond to the interaction with oxygenic phototrophic organisms (cianobacteria); and (3) nitrogen metabolism is very conservative due to the high abundance of fixers and the scarcity of nitrate-reducer microorganisms.
Biomassa microbiana do solo em sistema de integra??o lavoura-pecuária em plantio direto, submetido a intensidades de pastejo
Souza, Edicarlos Damacena de;Costa, Sérgio Ely Valad?o Gigante de Andrade;Anghinoni, Ibanor;Lima, Christina Venzke Sim?es de;Carvalho, Paulo César de Faccio;Martins, Amanda Posselt;
Revista Brasileira de Ciência do Solo , 2010, DOI: 10.1590/S0100-06832010000100008
Abstract: in integrated crop-livestock systems most of the nutrient supply for a pasture is provided by animal excretions, in the form of manure or urine, stimulating the activity and accumulation of nutrients in the cells. this study was carried out in an integrated crop-livestock system under no-tillage, initiated in 2001, with the objective of evaluating the impact of different winter grazing intensities (black oat + italian ryegrass; 10, 20, and 40 cm, and a no-grazing control treatment) on microbial activity and on carbon, nitrogen and phosphorus concentration and stocks in microbial biomass in the 0-10 cm layer of an oxisol (latosol), in southern brazil, during a grazing cycle. biomass nutrient contents and stocks and microbial activity were affected by grazing intensities and by the season of the grazing cycle. microbial carbon and phosphorus contents increased in the beginning of the grazing cycle in may until the period of high phytomass production in september, after which these contents decreased, following the pasture senescence. on the other hand, microbial nitrogen decreased from may to november, possibly as a result of plant uptake of soil n. integrated crop-livestock systems under no-tillage maintain soil biological quality, and are, under adequate grazing intensity, similar to no-tillage systems without grazing influence. however, at high grazing intensities (10 cm) under water stress, this soil quality is negatively affected.
Efeito do sistema de plantio e doses do nicosulfuron sobre a atividade microbiana do solo
Camelo, G.N;Santos, J.B;Lazari, T.M;Oliveira, T.A;Santos, E.A;Ferreira, E.A;Pereira, G.A.M;
Planta Daninha , 2011, DOI: 10.1590/S0100-83582011000400013
Abstract: this study aimed to evaluate the effect of atrazine + nicosulfuron on soil microbial activity, under the conventional and no-tillage systems. the experiment was carried out in an area of maize-brachiaria intercropping, where atrazine + nicosulfuron were applied at (1,500 + 10 and 1,500 + 30 g h-1) with a weed-handed area being maintained without prior cultivation and another area without weed control. at flowering, soil samples were collected to determine the rate of co2 unfastening, microbial biomass carbon (mbc) and metabolic quotient (qco2) using the relation between accumulated co2 and mbc. the rate of co2 unfastening was lower only in plots without weed control. mbc was higher in the no-tillage system, being negatively affected due to the absence of vegetation. lower mbc was observed in the weed-handed areas, probably due to the absence of straw. under no-tillage system conditions, no difference was observed between the soil treatments with herbicide application and those without weed control. it can be concluded that the evaluated microbiological indicators were sensitive to the treatments, showing lower soil disturbance under no-tillage system conditions. however, in crop-livestock integration under the conventional system, the negative herbicide effect increase of nicosulfuron rate.
Indicadores biológicos de qualidade do solo em diferentes sistemas de uso no brejo paraibano
P?rto, M?nica Lima;Alves, Jailson do Carmo;Diniz, Adriana Araújo;Souza, Adailson Pereira de;Santos, Djail;
Ciência e Agrotecnologia , 2009, DOI: 10.1590/S1413-70542009000400010
Abstract: soil quality evaluation is an important tool for the monitoring of soil degradation as well as for planning the adoption of sustainable agricultural management practices. the objective of this study was to evaluate some biological indicators of the soil quality of a dystrophic yellow latosol (oxisol) under different land use systems in areia, paraíba, brazil. soil samples were taken form the plow layer (0-20 cm) at six sites: native vegetation (moist atlantic forest), fruit culture (cashew crop), sugarcane, crop succession (sorghum/common bean/castor bean), pasture (brachiaria decumbens), and a combined cropping system (castor bean + sorghum). total organic carbon (toc), microbial biomass carbon (mbc), microbial quotient (qmic), basal respiration (br) and metabolic quotient (qco2) were evaluated. the results indicated that treatments under grasses, such as sugarcane and pasture, showed a tendency to maintain the toc contents with lower reductions in mbc. however, higher qco2 values were found under these treatments, which may indicate the occurrence of degradation processes. slight reductions in toc and mbc values and low qco2 values were verified in the cashew crop, suggesting that the soil under this system could be adjusting to a new equilibrium state. crop succession and combined cropping system treatments had the largest reductions in toc and mbc with the highest qco2 values, which suggests a stage of advanced degradation. it can be concluded that all the agroecosystems evaluated in this study resulted in loss of soil quality, which was pronounced in the most intensively managed treatments. the mbc and qco2 were highly sensitive to land use changes and show great potential for soil quality evaluations.
Association of Erectile Dysfunction and Hypogonadism with Metabolic Syndrome in Men with Lower Urinary Tract Symptoms of Younger and Older Age Groups  [PDF]
Elena Novikova, Vera Selyatitskaya, Igor Mitrofanov, Boris Pinkhasov, Ani Karapetyan
Advances in Sexual Medicine (ASM) , 2014, DOI: 10.4236/asm.2014.44009
Abstract: The aim of this study was to evaluate the incidence and severity of erectile dysfunction (ED) and hypogonadism in 193 men presenting with lower urinary tract symptoms (LUTSs) in the younger (20 - 39 years old) and older (40 - 60 years old) age groups depending on the presence of metabolic syndrome (MetS). Triglycerides, glucose and high-density lipoprotein cholesterol, serum total testosterone (TT), sex hormone-binding globulin, prostate-specific antigen, pituitary hormones levels were measured in serum. Standardized criteria (2009) were used to determine the prevalence of MetS. Patients were assessed based on the International Prostate Symptom Score (IPSS) and the IPSS-Quality of Life (IPSS-QoL) for LUTSs and the International Index of Erectile Function (IIEF) for ED. Hypogonadism was determined in accordance with the ISA, ISSAM, EAU, EAA and ASA recommendations. In men with MetS in the younger age group the incidence of ED was 2.4 times higher, and that of low TT level and hypogonadism was 8.4 times higher compared to men without the syndrome. In the older age group, an increased incidence of ED and low TT level in men with MetS compared to men without the syndrome was on the trend level, but the incidence of hypogonadism was for sure higher (by 1.6 times). In conclusion, the study showed that ED and hypogonadism are associated with MetS by a high degree of certainty in young men with LUTSs. In men of the older age group with LUTSs, the presence of MetS is not so clearly associated with ED and hypogonadism due to the fact that the incidence of these urogenital diseases is also high in men without MetS.
Soil biological attributes in pastures of different ages in a crop-livestock integrated system
Muniz, Luciano Cavalcante;Madari, Beata Em?ke;Trovo, José Benedito de Freitas;Cantanhêde, Ilka South de Lima;Machado, Pedro Luiz Oliveira de Almeida;Cobucci, Tarcísio;Fran?a, Aldi Fernandes de Souza;
Pesquisa Agropecuária Brasileira , 2011, DOI: 10.1590/S0100-204X2011001000021
Abstract: the objective of this work was to evaluate the effect of the pasture (urochloa brizantha) component age on soil biological properties, in a crop-livestock integrated system. the experiment was carried out in a brazilian savannah (cerrado) area with 92 ha, divided into six pens of approximately 15 ha. each pen represented a different stage of the pasture component: formation, p0; one year, p1; two years, p2; three years, p3; and final with 3.5 years, pf. samples were taken in the 0-10 cm soil depth. the soil biological parameters - microbial biomass carbon (mbc), microbial biomass respiration (c-co2), metabolic quotient (qco2), microbial quotient (qmic), and total organic carbon (toc) - were evaluated and compared among different stages of the pasture, and between an adjacent area under native cerrado and another area under degraded pasture (pcd). the mbc, qmic and toc increased and qco2 reduced under the different pasture stages. compared to pcd, the pasture stages had higher mbc, qmic and toc, and lower qco2. the crop-livestock integrated system improved soil microbiological parameters and immobilized carbon in the soil in comparison to the degraded pasture.
Impacto do glyphosate associado a inseticida e fungicida na atividade microbiana e no potencial de solubiliza??o de fosfato em solo cultivado com soja Roundup Ready?
Reis, M.R.;Silva, A.A.;Freitas, M.A.M.;Pereira, J.L.;Costa, M.D.;Pican?o, M.C.;Ferreira, E.A.;Belo, A.F.;Coelho, A.T.C.P.;Silva, G.R.;
Planta Daninha , 2009, DOI: 10.1590/S0100-83582009000400011
Abstract: the objective of this work was to evaluate the microbial activity and phosphate solubilization potential of a soil cultivated with soybean under different phytosanitary management strategies. the experiment was conducted in the field in a cambic red-yellow argisol. ten treatments were arranged in a randomized block design with four replications. the effect of fungicide + herbicide application (endosulphan + tebuconazole) was evaluated in the plots, while weed control management was studied in the subplots (hoed or unhoed control; single-dose or sequential glyphosate application; single-dose fomesafen + fluazifop-p-butil application). soil samples from the inter-row were collected when plants reached the r2 stage and were used to measure soil respiratory rate, microbial biomass carbon (mbc), metabolic quotient (qco2), phosphate solubilization potential, and ph. the phyto-sanitary management strategies evaluated did not affect soil respiratory rates. the herbicides tested influenced soil mbc and qco2, variables directly related to soil quality. glyphosate applied in a single dose or sequentially, either in combination with endosulphan + tebuconazole or not, led to lower qco2 values (0.075-0.079 mg μg-1 d-1) and higher mbc (239.64 - 312.82 μg g-1), indicating less soil disturbance. higher phosphate solubilizing activity, 425 and 472 mg l-1 , were observed for the treatments with single-dose or sequential application of glyphosate, respectively, in the absence of endosulfan + tebuconazole. agrochemical application on soybean shoots affects the activity of soil microorganisms in the plant rhizosphere.
Carbono organico e fósforo microbiano em sistema de integra??o agricultura-pecuária submetido a diferentes intensidades de pastejo em plantio direto
Souza, Edicarlos Damacena de;Costa, Sergio Ely Valad?o Gigante de Andrade;Lima, Christina Venzke Sim?es de;Anghinoni, Ibanor;Meurer, Egon José;Carvalho, Paulo César de Faccio;
Revista Brasileira de Ciência do Solo , 2008, DOI: 10.1590/S0100-06832008000300035
Abstract: integrated crop-livestock systems have attracted more interest in the last few years due to their capacity of improving stability and sustainability of agricultural systems as compared to more specialized production systems. soil organic carbon content has been used as an indicator of soil sustainability and stability. in this sense, this study aimed to measure the stocks of total organic carbon fractions and phosphorus in the microbial biomass in a rhodic hapludox (oxisol) under integrated crop-livestock system with different grazing intensities in the winter. soil samples were collected in november 2006 in s?o miguel das miss?es, state of rio grande do sul, brazil. the experimental area had been cultivated under no-tillage for 10 years before implementing the integrated system in 2001. the experimental design was completely randomized blocks with three replicates. the treatments consisted of grazing intensities represented by sward heights of 10, 20 and 40 cm during the pasture cycle in winter. this pasture was composed of a black oat (avena strigosa schreb) and italian ryegrass (lolium multiflorum lam.) mix, and a control area with no grazing. total and particulate organic matter (pom) carbon stocks, phosphorus and carbon content in the microbial biomass, as well as microbial biomass activity were evaluated. the total organic stocks carbon were not affected by grazing intensities; however, the stocks of pom carbon were smaller in soils under the highest grazing intensity. the microbial biomass was stimulated at the highest grazing intensity, in which greater root growth was observed. the phosphorus content in the microbial biomass increased linearly with the decrease of the grazing intensity, while an inverse pattern was observed for the microbial biomass. particulate organic matter carbon was more sensitive to changes in soil organic carbon under the experimental pasture management.
Atributos biológicos indicadores da qualidade do solo em pastagem cultivada e nativa no Pantanal
Cardoso, Evaldo Luis;Silva, Marx Leandro Naves;Moreira, Fátima Maria de Souza;Curi, Nilton;
Pesquisa Agropecuária Brasileira , 2009, DOI: 10.1590/S0100-204X2009000600012
Abstract: the objective of this work was to evaluate the changes in biological attributes soil promoted by substitution native forest cultivated pasture, and submission pasture under continuous grazing pantanal wetlands. consisted evaluation three forests, brachiaria decumbens pastures of different formation ages, established in substitution to the native forests and three native pastures, one under continuous grazing and two without grazing for 3 and 19 years. soil samples were collected at 0-10 and 10-20 cm depths, in the three 100-m transects in each sampled site. each transect represented one replicate. the following attributes were evaluated: total organic carbon (toc), soil microbial carbon (cmic), microbial quotient (qmic), basal respiration (br) and metabolic quotient (qco2). the substitution of the native forest by cultivated pasture reduced toc, cmic, and qmic and increased br. the continuous grazing on native pasture reduced toc and cmic contents. cmic was the most sensitive attribute to the alterations imposed on soil by the cultivated and native pasture systems, since it was marked by more substantial reductions.
Atributos biológicos do solo sob influência da cobertura vegetal e do sistema de manejo
Silva, Mozaniel Batista da;Kliemann, Huberto José;Silveira, Pedro Marques da;Lanna, Anna Cristina;
Pesquisa Agropecuária Brasileira , 2007, DOI: 10.1590/S0100-204X2007001200013
Abstract: the objective of this work was to evaluate the effects of cover crops and direct and conventional tillage systems on soil biological attributes when cultivated with dry bean in winter under sprinkle irrigation. the experiment was conducted in santo ant?nio de goiás, go, brazil, in a clayey rhodic haplustox. cover crops were cultivated annually in the summer since 2001, using brachiaria brizantha, cajanus cajan, pennisetum glaucum, panicum maximum, sorghum, stylosanthes guianensis, brachiaria in association with corn, and native vegetation as reference. in 2005, 60 days after cutting the cover crops, brs valente bean cultivar, under irrigation, was cultivated. sowing was performed on june 16, 2005 and the harvest on september 19, 2005. soil samples were collected to a depth of 0-10 cm, in november 2004 (before cover crops planting), june 2005 (before dry bean planting) and july 2005 (at dry bean flowering). evaluations of basal respiration, carbon and nitrogen of microbial biomass, microbial/organic carbon ratio, microbial/total nitrogen ratio and metabolic quotient were performed. soil biological attributes were influenced by cover crops, soil management and sampling time.
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