Logarithmic Functions
Mostrando 13-24 de 33 artigos, teses e dissertações.
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13. Siderophore production by Enterobacter cloacae and a common receptor protein for the uptake of aerobactin and cloacin DF13.
Iron-starved cultures of Enterobacter cloacae produced two siderophores, identified as enterochelin and aerobactin. The aerobactin was excreted in larger amounts than was enterochelin, and it was synthesized preferentially in the late logarithmic and stationary growth phases under iron-deficient conditions. Enterochelin was synthesized by cultures in the log
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14. Spatial integration and sensitivity changes in the human rod visual system.
1. The factor by which increment threshold rises with increasing background intensity is less if the target is small than if it is large. The difference is usually attributed to a reduction in the area over which visual signals are integrated as the visual system light adapts. Recently, however, it has been argued that the difference in slope may instead be
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15. Quantitative control of the stationary phase-specific sigma factor, sigma S, in Escherichia coli: involvement of the nucleoid protein H-NS.
In Escherichia coli, recent intensive studies revealed that expression of a certain subset of genes is under the control of the stationary phase-specific sigma factor, sigma S, which is encoded by the rpoS gene. Since sigma S functions predominantly under certain growth conditions, its activity and/or cellular content has accordingly to be tightly controlled
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16. Growth state-dependent phenotypes of adult hepatocytes in primary monolayer culture.
A proliferation-competent adult rat liver cell monolayer system has been analyzed for tissue-specific functions during its growth cycle. High levels of the adult (L type) form of pyruvate kinase (EC 2.7.1.40) and glutathione S-transferase B ("ligand," EC 2.5.1.18) are observed during the early lag phase; they decline markedly during the logarithmic phase and
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17. Functional Genomics: Expression Analysis of Escherichia coli Growing on Minimal and Rich Media
DNA arrays of the entire set of Escherichia coli genes were used to measure the genomic expression patterns of cells growing in late logarithmic phase on minimal glucose medium and on Luria broth containing glucose. Ratios of the transcript levels for all 4,290 E. coli protein-encoding genes (cds) were obtained, and analysis of the expression ratio data indi
American Society for Microbiology.
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18. Regulatory mutants and control of cysteine biosynthetic enzymes in Salmonella typhimurium.
The cysB region in Salmonella typhimurium regulates in a positive manner the noncontiguous structural genes for the enzymes responsible for sulfate reduction in cysteine biosynthesis. We treated three cysB mutants with chemical mutagens and selected 81 secondary mutants in which the inability to utilize sulfate was suppressed. Growth experiments on the suppr
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19. Induction of Neuronal Functions: Acetylcholine-Induced Acetylcholinesterase Activity in Mouse Neuroblastoma Cells
Addition of acetylcholine to growing cultures of mouse neuroblastoma cells induced a 37-fold increase in the specific activity of acetylcholinesterase (EC 3.1.1.7). Morphological changes, consisting of neurite-extensions, were also observed during the logarithmic phase of growth of cells stimulated with acetylcholine. A histochemical procedure for localizati
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20. The Bacillus subtilis sigma D-dependent operon encoding the flagellar proteins FliD, FliS, and FliT.
During a genetic screen to identify metalloregulated loci in Bacillus subtilis, we isolated a Tn917-lacZ insertion in the second gene of an operon downstream of the flagellin (hag) gene. Sequence analysis indicates that this gene encodes a homolog of the enteric flagellar filament cap protein FliD. The fliD gene is followed by homologs of the fliS and fliT g
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21. Deletion analysis of the fis promoter region in Escherichia coli: antagonistic effects of integration host factor and Fis.
Fis is a small DNA-binding and -bending protein in Escherichia coli that is involved in several different biological processes, including stimulation of specialized DNA recombination events and regulation of gene expression. fis protein and mRNA levels rapidly increase during early logarithmic growth phase in response to a nutritional upshift but become virt
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22. Sequence, regulation, and functions of fis in Salmonella typhimurium.
The fis operon from Salmonella typhimurium has been cloned and sequenced, and the properties of Fis-deficient and Fis-constitutive strains were examined. The overall fis operon organization in S. typhimurium is the same as that in Escherichia coli, with the deduced Fis amino acid sequences being identical between both species. While the open reading frames u
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23. Immunocytochemical Localization of a Calmodulinlike Protein in Bacillus subtilis Cells
To determine possible functions of the calmodulinlike protein of Bacillus subtilis, the time course of its expression during sporulation and its cellular localization were studied. The protein was expressed in a constitutive manner from the end of logarithmic growth through 8 h of sporulation as determined by antibody cross-reactivity immunoblots and enzyme-
American Society for Microbiology.
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24. The Sampling Distribution of Disease-Associated Alleles
A theory is developed that provides the sampling distribution of low frequency alleles at a single locus under the assumption that each allele is the result of a unique mutation. The numbers of copies of each allele is assumed to follow a linear birth-death process with sampling. If the population is of constant size, standard results from theory of birth-de