Eco Dynamics
Mostrando 13-23 de 23 artigos, teses e dissertações.
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13. Evolution, population dynamics, and stability
By treating mutant populations as fluctuations relating to the structural stability of the equations of population dynamics, a criterion is developed permitting the prediction of long-term population trends in an evolving eco-system. As an illustration it is shown that the ratio of predator to prey biomass increases under the effects of their combined evolut
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14. Structural analysis of a mutational hot-spot in the EcoRV restriction endonuclease: a catalytic role for a main chain carbonyl group.
Following random mutagenesis of the Eco RV endonuclease, a high proportion of the null mutants carry substitutions at Gln69. Such mutants display reduced rates for the DNA cleavage step in the reaction pathway, yet the crystal structures of wild-type Eco RV fail to explain why Gln69 is crucial for activity. In this study, crystal structures were determined f
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15. Rapid contemporary evolution and clonal food web dynamics
Character evolution that affects ecological community interactions often occurs contemporaneously with temporal changes in population size, potentially altering the very nature of those dynamics. Such eco-evolutionary processes may be most readily explored in systems with short generations and simple genetics. Asexual and cyclically parthenogenetic organisms
The Royal Society.
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16. Mitochondrial DNA ligase function in Saccharomyces cerevisiae
The Saccharomyces cerevisiae CDC9 gene encodes a DNA ligase protein that is targeted to both the nucleus and the mitochondria. While nuclear Cdc9p is known to play an essential role in nuclear DNA replication and repair, its role in mitochondrial DNA dynamics has not been defined. It is also unclear whether additional DNA ligase proteins are present in
Oxford University Press.
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17. Base pair opening dynamics of a 2-aminopurine substituted Eco RI restriction sequence and its unsubstituted counterpart in oligonucleotides.
Studies of 1H NMR selective saturation recovery were performed to determine the imino proton exchange with solvent water of the base pairs in the Eco RI endonuclease recognition sequence GAATTC, placed at the center of self-complementary decamer and dodecamer oligonucleotides. In one oligonucleotide the innermost adenine was replaced by the fluorescent base
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18. Dynamics of cruciform extrusion in supercoiled DNA: use of a synthetic inverted repeat to study conformational populations.
An inverted repeat has been created in a plasmid by ligation of two 13 nucleotide synthetic oligonucleotides into the cloning vector pAT153. The resulting recombinant plasmid, pIRbke8, is hypersensitive to cleavage by the single-strand-specific nuclease S1, and to modification by the single-strand-selective reagent bromoacetaldehyde, when the plasmid is nega
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19. DNA Fingerprinting with a Dispersed Repeated Sequence Resolves Pathotype Diversity in the Rice Blast Fungus.
The poor definition of pathotype variation in the rice blast fungus has historically handicapped strategies for reducing blast disease damage to the world's rice crop. We have employed a probe for a dispersed repeated DNA sequence called MGR [Hamer et al. (1989). Proc. Natl. Acad. Sci. USA 86, 9981-9985] to construct genotype-specific, EcoRl restriction frag
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20. Eco-evolutionary dynamics: disentangling phenotypic, environmental and population fluctuations
Decomposing variation in population growth into contributions from both ecological and evolutionary processes is of fundamental concern, particularly in a world characterized by rapid responses to anthropogenic threats. Although the impact of ecological change on evolutionary response has long been acknowledged, the converse has predominantly been neglected,
The Royal Society.
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21. Do Woody Plants Operate Near the Point of Catastrophic Xylem Dysfunction Caused by Dynamic Water Stress? 1: Answers from a Model
We discuss the relationship between the dynamically changing tension gradients required to move water rapidly through the xylem conduits of plants and the proportion of conduits lost through embolism as a result of water tension. We consider the implications of this relationship to the water relations of trees. We have compiled quantitative data on the water
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22. How do site-specific DNA-binding proteins find their targets?
Essentially all the biological functions of DNA depend on site-specific DNA-binding proteins finding their targets, and therefore ‘searching’ through megabases of non-target DNA. In this article, we review current understanding of how this sequence searching is done. We review how simple diffusion through solution may be unable to account for the rapid r
Oxford University Press.
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23. Evaluation of the Role of Syringomycin in Plant Pathogenesis by Using Tn5 Mutants of Pseudomonas syringae pv. syringae Defective in Syringomycin Production †
Syringomycin is a necrosis-inducing phytotoxin produced by Pseudomonas syringae pv. syringae. To determine whether syringomycin production is a determinant in virulence or pathogenicity, we isolated nontoxigenic (Tox−) Tn5-containing mutants and then quantitatively evaluated them for the ability to multiply and cause disease in immature sweet-cherry fruits