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Search Results: 1 - 10 of 1103 matches for " Veronica Massena; "
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COMO FAZER UMA AGRICULTURA VERDE USANDO O MAIS ANTIGO PROCESSO DE OBTEN O DE NITROGêNIO EM PLANTAS
Veronica Massena Reis
Acta Scientiae et Technicae , 2013,
Abstract: Around 78% of the air is composed by nitrogen and this element is the third most important to the maintenance of life on the planet, after the carbon (C) and oxygen (O). The great paradox is life in earth it that this gas (N2) is inert and can only be reduced to a form assimilated by plants by different genus of bacteria called diazotrophs. These bacteria interact with other organisms including agricultural crops as the most famous one, the rhizobia of soybean. Another example recently incorporated to the cereal production routine is the application of another bacterium called Azospirillum brasilense described by the research group of Johanna D berenier in the 80’s. The association of diazotrophs and grasses has been studied for about 60 years and revealed that in addition to providing nitrogen to the crops (contributing with up to 58% of its necessity), can also produce phyto-hormones, act as a biocontrol agents, solubilize phosphates and some other features; helping plants in the response of environmental stresses and refl ecting in crop productivity using reduced doses of N-fertilizer. With the objective of develop a crop management based on biological nitrogen fi xation and a recommendation of inoculant application in order to improve the utilization of N-fertilizers, also preconized by the green revolution, made this research recognized worldwide for its innovation that advocates the use of a conservative practice, keeping the man in the fi eld, producing more without harming the environment.
Produ??o, caracteriza??o e aplica??o de anticorpo policlonal contra Azospirillum amazonense estirpe Am15
Silva, Marinete Flores da;Reis, Veronica Massena;
Bragantia , 2009, DOI: 10.1590/S0006-87052009000100001
Abstract: molecular and immunological approaches are useful for monitoring the localization of microrganism used as agricultural inoculants. a successful example is the use of a diazotrophic bacteria, as soybean in brazil. however, as diazotrophic bacterias other than rizobium do not form nodular structures, the localization of the specific site where nitrogen reduction occurs is impossible. in this study, carried out at embrapa agrobiology, a polyclonal antibody against azospirillum amazonense (as-am15) was to produced and characterized through an indirect enzyme linked immunosorbent assay (elisa). maize seedscoated with peat containing the target bacterium were enoculated with the policlonal antibody and evaluated during 60 days. the antibody was able to quantify bacteria populations in samples where the minimal cell number were superior to 100,000 cells l-1. according to these results, the policlonal antibody as-am15 showed high specificity to the target antigen and was able to quantify or monitor azospirillum strains and able to be used as a control of the quality of a peat inoculant product.
Uso de diferentes fontes de carbono por estirpes de Gluconacetobacter diazotrophicus isoladas de cana-de-a?úcar
Barbosa, Edilene Alves;Perin, Liamara;Reis, Veronica Massena;
Pesquisa Agropecuária Brasileira , 2006, DOI: 10.1590/S0100-204X2006000500015
Abstract: the objective of this work was to quantify the population of gluconacetobacter diazotrophicus present in plantlets of 34 sugarcane varieties and to characterize the isolates according to their capacity to use carbon sources and produce pink pigments under light. g. diazotrophicus population was estimated using the most probable number technique, and then, isolated in semi-selective culture media. the highest population number of g. diazotrophicus was found in the roots; brazilian varieties presented the highest population. the isolates used little carbon sources, and those strains obtained from the root used the highest number of carbon sources. only the strain ppe-4 and four other ones produce pink pigments under light. the low variation observed may be related to the habitat or to the adaptation of this population to specific internal plant conditions, and for this reason, the genetic structure of these bacteria is limited and preserved.
Diversidade de Gluconacetobacter diazotrophicus isolada de plantas de cana-de-a?úcar cultivadas no Brasil
Perin, Liamara;Baldani, José Ivo;Reis, Veronica Massena;
Pesquisa Agropecuária Brasileira , 2004, DOI: 10.1590/S0100-204X2004000800006
Abstract: the objective of this study was to evaluate the diversity of gluconacetobacter diazotrophicus isolates from different sugarcane (saccharum spp.) varieties. this study was developed using 123 strains from the internal tissues of stems and roots, isolated from 80 species and hybrids of sugarcane, originated from different countries and maintained in two germoplasm collections localized in bahia and rio de janeiro states. five isolates obtained from coffee plants (coffea arabica), two from pineapple (ananas comosus), one from pennisetum purpureum and 10 strains, which present different electrophoretic patterns, were used in the comparison. cluster analysis of enzyme-linked immunosorbent assay (elisa) results suggested that variations were not correlated with the plant species, sugarcane variety, geographic origin, parts of plants nor with sampling time. high nitrogen doses lowered the diversity of g. diazotrophicus.
Ocorrência de micorrizas arbusculares e da bactéria diazotrófica Acetobacter diazotrophicus em cana-de-a?úcar
Reis, Veronica Massena;Paula, Mauro Augusto de;D?bereiner, Johanna;
Pesquisa Agropecuária Brasileira , 1999, DOI: 10.1590/S0100-204X1999001000021
Abstract: the occurrence and distribution of species of arbuscular mycorrhizae fungi and acetobacter diazotrophicus in sugar cane (saccharum officinarum) grown in different regimes of crop management in the states of rio de janeiro and pernambuco, brazil, were studied. thirty five samples of the rhizosphere soil and roots were collected from 14 varieties of sugar cane for the extraction of spores and isolation of the bacterium. the number of spores varied from 18 to 2,070 per 100 ml of soil, and the greatest diversity of fungal species was found in the sugarcane fields of campos (rio de janeiro state), especially in those where the sugarcane trash was not burned at harvest. the predominant species found in the three localities sampled were: scutellospora heterogama, glomus etunicatum, glomus occultum, acaulospora sp. and gigaspora margarita. a. diazotrophicus was present in almost all samples of root with the exception of one harvest of sugar cane taken from an area used for the sedimentation of vinasse (distillery waste). it was not possible to detect the bacterium from surface sterilized spores of native arbuscular mycorrhizal fungi (amf), only from washed ones using sterile water.
Quantification of natural populations of Gluconacetobacter diazotrophicus and Herbaspirillum spp. In sugar cane (Saccharum spp.) Using differente polyclonal antibodies
Silva-Froufe, Lúcia Gracinda da;Boddey, Robert Michael;Reis, Veronica Massena;
Brazilian Journal of Microbiology , 2009, DOI: 10.1590/S1517-83822009000400018
Abstract: the species gluconacetobacterdiazotrophicus, herbaspirillum seropedicae and h. rubrisubalbicans are endophytic n2-fixing [diazotrophic] bacteria which colonise not only roots, but also the aerial tissue of sugar cane. however, the technique most commonly used to quantify the populations of these microbes in plants is by culturing serial dilutions of macerates of plant tissues in n free semi-solid media which are only semi-selective for the species/genera [the most probable number (mpn) technique] and each culture must be further subjected to several tests to identify the isolates at the species level. the use of species-specific polyclonal antibodies with the indirect elisa (enzyme-linked immunosorbent assay) can be an alternative which is rapid and specific to quantify these populations of bacteria. this study was performed to investigate the viability of adapting the indirect elisa technique to quantify individually the populations of these three species of diazotroph within the root and shoot tissues of sugarcane. the results showed that species-specific polyclonal antibodies could be obtained by purifying sera in protein-a columns which removed non-specific immuno-globulins. it was possible to quantify the three bacterial species in the brazilian sugarcane variety sp 70-1143 in numbers above 105 cells per g fresh weight in roots, rhizomes and leaves. the numbers of the different bacterial species evaluated using the elisa technique were found to be higher than when the same populations were evaluated using the mpn technique, reaching 1400 times greater for g. diazotrophicus and 225 times greater for herbaspirillum spp. these results constitute the first quantification of herbaspirillum using immunological techniques.
Isolamento de Gluconacetobacter spp. em diferentes tipos de solos
Santos, Carla Cristiane Rocha dos;Perin, Liamara;Baldani, José Ivo;Reis, Veronica Massena;
Pesquisa Agropecuária Brasileira , 2006, DOI: 10.1590/S0100-204X2006000100012
Abstract: the objective of this work was to improve the immunocapture method for the application to soil samples containing high levels of clay particles and to utilize it for the isolation of gluconacetobacter diazotrophicus strains from soil cultivated with sugarcane and coffee. the immunocapture technique was applied successfully for isolation of bacterium from soil samples. the modified immunocapture technique with al2(so4)3 allowed the application of the method using clayed soil samples by the flocculation of the suspended clay. it proved to be effective for isolation of g. diazotrophicus inoculated in sterile sandy and clay soils five days after inoculation. the maximum sensitivity of the method to isolate g. diazotrophicus cells, using pure culture, was 103 cells ml-1. the modification of the technique allows the capture of gluconacetobacter spp. from soil samples near the coffee plants but not from sugarcane soils.
Resposta do dendezeiro à adi??o de nitrogênio e sua influência na popula??o de bactérias diazotróficas
Carvalho, André Vieira de;Alves, Bruno José Rodrigues;Reis, Veronica Massena;
Pesquisa Agropecuária Brasileira , 2006, DOI: 10.1590/S0100-204X2006000200014
Abstract: african oil palm (elaeis guineensis, jaquim) can produce up to 7 tons of oil per hectare per year. the vegetable oil is greatly versatile in its use, since food industry up to the production of fuels favorable to environmental protection. the plant has the potential to be associative with diazotrophic bacteria which colonize the roots and stem. the objective of this work was to evaluate 17 genotypes of e. guineensis in response to nitrogen addition and to verify the influence of this nitrogen on the diazotrophic population in an experiment using plastic pots filled with 50% quartz sand and 50% of non sterilized horizon b; red-yellow podzolic soil series itaguaí, extremely poor in nitrogen. urea was used at a dose of 33.68 kg ha-1 de n. in the presence of the nitrogen, all genotypes improved biometric parameters, increased total nitrogen and its accumulation. its addiction did not affect the diazotrophic population. two genotypes were selected in the presence and absence of nitrogen: c-2001 and la mé, respectively.
Diversidade de bactérias diazotróficas endofíticas dos gêneros Herbaspirillum e Burkholderia na cultura do arroz inundado
Rodrigues, Luciana da Silva;Baldani, Vera Lucia Divan;Reis, Veronica Massena;Baldani, José Ivo;
Pesquisa Agropecuária Brasileira , 2006, DOI: 10.1590/S0100-204X2006000200012
Abstract: the objective of this work was to evaluate the diversity of endophytic diazotrophic bacteria of the genera herbaspirillum and burkholderia, in two rice varieties, considered of high (ir 42) and low (iac 4440) contribution on bnf. two experiments were conducted in greenhouse conditions, in order to study the association of endophytic diazotrophic bacteria with wetland rice varieties, which were planted in two types of soil: one from rio de janeiro state and another from goiás state, brazil. bacterial population (in different parts) and physiological stages of the plants were evaluated, followed by the both genera strains isolation using culture media. the isolated bacteria were characterized based on morphological and physiological aspects. high bacterial counts were detected (106 cells g-1 fresh weight), especially in root samples of both rice varieties. the majority of the isolates were used for characterization, and the data obtained from the similarity matrix showed the presence of isolates belonging to herbaspirillum seropedicae, while other isolates were clustered into the burkholderia genus.
Aera??o e adi??o de sais na produ??o de ácido indol acético por bactérias diazotróficas
Radwan, Tharwat El-Sayed El-Desouk;Mohamed, Zeinat Kamel;Reis, Veronica Massena;
Pesquisa Agropecuária Brasileira , 2005, DOI: 10.1590/S0100-204X2005001000008
Abstract: the production of indolic compounds by azospirillum brasilense cd, a. lipoferum br 17, herbaspirillum seropedicae z 67, h. rubrisubalbicans m4, and strain 34 isolated from rice, which does not fit into the described herbaspirillum species, was measured under aeration ratio and salt concentrations. aeration of the medium increased growth and production of indole compounds by these bacteria. under static condition, the production was higher both in nitrogen-free medium for azospirillum, and in amended n medium for the herbaspirillum strains. increasing salt concentration into the medium inhibited the production of indole compounds, although a small increase in production was observed, when cacl2 concentration was raised above 1 g l-1. deleterious effect of salinity was more pronounced in the presence of nahco3, followed by nacl and na2so4. azospirillum produced more indolic compounds in semi-solid cultures, and herbaspirillum in liquid medium, but at lower levels.
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