Flac
Mostrando 13-24 de 107 artigos, teses e dissertações.
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13. ANALYSIS OF THE DISPLACEMENT FIELD IN THE STABILITY OF HIGH-RISE MINING SLOPES / ANÁLISIS DEL CAMPO DE DESLOCAMIENTOS PARA ESTABILIDAD DE TALUD DE GRANDE ALTURA EN MINERACIÓN / ANÁLISE DO CAMPO DE DESLOCAMENTOS PARA ESTABILIDADE DE TALUDES DE GRANDE ALTURA EM MINERAÇÃO
The evaluation of the stability of the Robert Pit Mine (Canada) is made through the field of displacements of superficial and ground marks and possible rupture mechanisms obtained from the results of tension-deformation analysis by using the program computational FLAC (V. 3.30). Two constitutive models, the elastic perfectly plastic model and elastic-plastic
Publicado em: 1999
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14. Plasmid-Associated Functions of a Stable Flac
Several functions associated with the stable plasmid, FlacS, have been examined. Our results indicate that the sex pili synthesized by Escherichia coli strains carrying FlacS are altered in some manner as evidenced by a very inefficient adsorption of male-specific phages. On the other hand, FlacS-mediated entry exclusion of related plasmids and plasmid incom
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15. Inhibition of Replication of an F′lac Episome in Hfr Cells of Escherichia coli
Hfr strains of Escherichia coli K-12 were found capable of accepting a F′lac episome during mating, with a frequency approximating that of F− strains. However, the F′lac episome was unable to replicate in the Hfr cells, and was diluted out during the growth of the culture. The lac+ gene of the episome can be “rescued” by recombination into the host
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16. Genetic Characterization of a Stable F′ lac Plasmid1
A mutant F′ plasmid has been isolated in a strain of Salmonella typhimurium harboring Fts114lac. This mutant, designated FlacS, exhibits unique genetic stability in strains of S. typhimurium and Escherichia coli. It shows no thermolability and is lost at frequencies of 20 to 100 times less than the wild-type F′lac (F42) in the same genetic backgrounds. T
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17. Recipient competence in F'lac matings of Escherichia coli K-12.
We studied recipient mating ability in the presence of excess F'lac donors. Ninety-five percent of recipients were able to receive F'lac in 30-min matings. Competition between an F'-lac donor and an F'lac traI donor, which mobilized a ColE1 derivative (pML2), showed that each recipient mated with an average of two to three donors in 30 min. Experiments in wh
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18. Cell cycle analysis of F'lac replication in Escherichia coli B/r.
The timing and control of replication of an F'lac plasmid was investigated in two substrains of Escherichia coli B/r lac/F'lac growing at a variety of rates. The cellular content of covalently closed circular F'lac deoxyribonucleic acid and the cellular mass at the time of F'lac replication both increased as a function of growth rate. The timing of plasmid r
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19. Repression of the Virulence of Yersinia pestis by an F' Plasmid
An F-lac plasmid from Escherichia coli was transferred to virulent Yersinia pestis, resulting in the repression of virulence. The Y. pestis F-lac clones retained all of the known virulence traits but were avirulent and calcium independent. Every lac segregant derived from the F-lac clones was fully virulent and calcium dependent.
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20. Electron Microscopic Evidence for Linear Insertion of Bacteriophage MU-1 in Lysogenic Bacteria
Temperate bacteriophage Mu-1 was used to generate a lysogenic derivative of the F′lac episome of Escherichia coli. Intact, covalently circular molecules of F′lac and lysogenic F′lac Mu+ deoxyribonucleic acid (DNA) were isolated and examined by electron microscopy. The mean contour lengths of F′lac and F′lac Mu+ molecules were 37.6 ± 0.4 μm and 53
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21. Control of F′lac Replication in Escherichia coli B/r
The timing of replication of an F′lac plasmid during the division cycle of Escherichia coli B/r lac−/F′lac was examined in relation to the timing of initiation of chromosome replication. This was accomplished by measuring the induction of β-galactosidase and the incorporation of radioactive thymidine into cells at different ages in cultures growing ex
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22. Integration of the Vwa plasmid into the chromosome of Yersinia pestis strains harboring F' plasmids of Escherichia coli.
Conditional virulent strains of Yersinia pestis were used as recipients of an F-lac plasmid from either Escherichia coli 23.10S or E. coli CSH23. The transconjugants of Y. pestis were calcium independent; however, calcium dependence was restored after the loss of the E. coli plasmid. The plasmid contents of several Y. pestis F-lac clones were compared with t
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23. Conjugational Complementation Analysis of Transfer-Deficient Mutants of Flac in Escherichia coli
A series of 102 transfer-deficient (tra−) mutants of Flac (84 of which have been previously described) were classified as carrying frameshift, amber, ochre, UGA, and nonsuppressible mutations. Techniques were evolved for using cultures of F prime strains as efficient recipients in matings, for measuring the number of (F′/F′) heterozygote cells in trans
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24. Location of the Origin of Transfer of the Sex Factor F
The location of the origin of transfer on the map of Flac has been determined by two different techniques. The first showed that no transfer cistrons were transferred early by a transposition Hfr strain with a known point of chromosomal integration into Flac, and the second used a series of transfer-deficient Hfr deletion strains to map a locus required in c