Nutrient Competition
Mostrando 13-24 de 52 artigos, teses e dissertações.
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13. SOIL PHYSICAL AND BIOLOGICAL CHARACTERIZATION AFTER HERBICIDES APPLICATION IN BLACK WATTLE (Acacia mearnsii De Wild.) STANDS IN RIO GRANDE DO SUL / CARACTERIZAÇÃO FÍSICA E BIOLÓGICA DO SOLO APÓS APLICAÇÃO DE HERBICIDAS EM PLANTIOS DE ACÁCIA-NEGRA (Acacia mearnsii De Wild.) NO RIO GRANDE DO SUL
The study of soil quality biological indicators in areas classified as forest production units is important to understand the ecological processes that occur in these systems. Monitoring the soil fauna in modified environments, when management practices involve chemical products in the environment, is an instrument that allows to evaluate not only the soil q
Publicado em: 2008
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14. Efeitos da disponibilidade de luz e limitação de nutrientes sobre a competição entre cepas de Cylindrospermopsis raciborskii e Microcystis aeruginosa
The increase in occurrence and dominance of the cyanobacteria Cylindrospermopsis raciborskii in freshwater ecosystems, observed worldwide, has resulted, in many cases, in a replacement of other species like Microcystis aeruginosa. The factors related with this dominance are still unknown. The aim of this work was to evaluate the influence of light and nutrie
Publicado em: 2007
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15. Fertilization and dynamics of weeds under corn organic no- tillage system / Adubação e dinâmica de plantas daninhas em sistema de plantio direto orgânico de milho
The objective of this work was to evaluate and compare weed population establishment, foliar nutrient contents and corn production under conventional and organic no-tillage systems. The experiment was conducted in 2004/2005 and 2005/2006 at the Experimental Station of Coimbra, MG, owned by Universidade Federal de Viçosa, UFV. The treatments were constituted
Publicado em: 2007
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16. Directed dispersal by ants and post-dispersal regenerative phase of the ruderal species Ricinus communis L. (Euphorbiaceae) / Dispersão direcional por formigas e fase regenerativa pos-dispersão da especie ruderal Ricinus communis L. (Euphorbiaceae)
Plant reproduction through seeds has two phases: the regeneration of the individuals of a population and the establishment of the adult plants. The regenerative phase consists of many stages, such as seed release, dispersal, dormancy/quiescency and germination, and seedling establishment, each with differences in duration an? in mechanisms according to the s
Publicado em: 2006
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17. Plant diversity and ecosystem productivity: Theoretical considerations
Ecosystem processes are thought to depend on both the number and identity of the species present in an ecosystem, but mathematical theory predicting this has been lacking. Here we present three simple models of interspecific competitive interactions in communities containing various numbers of randomly chosen species. All three models predict that, on a
The National Academy of Sciences of the USA.
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18. rpoS Mutations and Loss of General Stress Resistance in Escherichia coli Populations as a Consequence of Conflict between Competing Stress Responses
The general stress resistance of Escherichia coli is controlled by the RpoS sigma factor (ϕS), but mutations in rpoS are surprisingly common in natural and laboratory populations. Evidence for the selective advantage of losing rpoS was obtained from experiments with nutrient-limited bacteria at different growth rates. Wild-type bacteria were rapidly displac
American Society for Microbiology.
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19. DNA as a Nutrient: Novel Role for Bacterial Competence Gene Homologs
The uptake and stable maintenance of extracellular DNA, genetic transformation, is universally recognized as a major force in microbial evolution. We show here that extracellular DNA, both homospecific and heterospecific, can also serve as the sole source of carbon and energy supporting microbial growth. Mutants unable to consume DNA suffer a significant los
American Society for Microbiology.
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20. Regulation of Porin-Mediated Outer Membrane Permeability by Nutrient Limitation in Escherichia coli
OmpF and OmpC porins were differentially regulated by nutrient limitation and growth rate in glucose- or nitrogen-limited chemostat cultures of Escherichia coli. Transcriptional and translational ompF fusions showed a sharp peak of expression under glucose limitation at D = 0.3 h−1, with lower amounts at lower and higher growth rates. The peak of OmpR-depe
American Society for Microbiology.
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21. Microbial Community Composition Affects Soil Fungistasis†
Most soils inhibit fungal germination and growth to a certain extent, a phenomenon known as soil fungistasis. Previous observations have implicated microorganisms as the causal agents of fungistasis, with their action mediated either by available carbon limitation (nutrient deprivation hypothesis) or production of antifungal compounds (antibiosis hypothesis)
American Society for Microbiology.
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22. Carbon nutrition of Escherichia coli in the mouse intestine
Whole-genome expression profiling revealed Escherichia coli MG1655 genes induced by growth on mucus, conditions designed to mimic nutrient availability in the mammalian intestine. Most were nutritional genes corresponding to catabolic pathways for nutrients found in mucus. We knocked out several pathways and tested the relative fitness of the mutants for col
National Academy of Sciences.
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23. Effect of Growth Conditions on Yield and Heme Content of Vitreoscilla
Vitreoscilla, a gliding bacterium in the Beggiatoaceae, is an obligate aerobe in which cytochrome o functions as the terminal oxidase. Protoheme IX is the only heme type present in this organism. The yield and heme content of Vitreoscilla cells grown in yeast extract, peptone, and acetate were dependent on growth conditions. Cells harvested in early stationa
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24. Polycyclic aromatic hydrocarbon degradation by a Mycobacterium sp. in microcosms containing sediment and water from a pristine ecosystem.
Microcosm studies were conducted to evaluate the survival and performance of a recently discovered polycyclic aromatic hydrocarbon (PAH)-degrading Mycobacterium sp. when this organism was added to sediment and water from a pristine ecosystem. Microcosms inoculated with the Mycobacterium sp. showed enhanced mineralization, singly and as components in a mixtur