Craven
Mostrando 13-24 de 45 artigos, teses e dissertações.
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13. Role of the avian retroviral protease in the activation of reverse transcriptase during virion assembly.
The retroviruses of the avian sarcoma-leukosis virus group synthesize their viral protease (PR) in two precursor forms--as a carboxy-terminal domain of the Gag precursor and as an embedded domain within the Gag-Pol precursor. We have shown previously that the Gag-derived PR is fully capable of processing the Gag precursor in the absence of the embedded PR (R
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14. Comparison of the sensitivity of two methods for isolation of Mycoplasma pneumoniae.
Throat swab specimens from 1,494 Marine Corps recruits were inoculated into vials containing diphasic (broth/agar) mycoplasma medium and also onto PPLO agar plates, which were subsequently overlayed with sheep erythrocytes in saline agar. Strains of Mycoplasma pneumoniae were isolated from 89 (6%) of the specimens by one or both of the methods. Eight-one of
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15. Necessity of the spacer peptide between CA and NC in the Rous sarcoma virus gag protein.
A mutant of Rous sarcoma virus was constructed in which the nine amino acids that separate the CA and NC sequences in the Gag protein were deleted. The spacer peptide deletion mutant produced particles containing the normal complement of viral RNA and all of the viral proteins, including reverse transcriptase. Though electron microscopy revealed particles of
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16. Activation and injury of Clostridium perfringens spores by alcohols.
The activation properties of Clostridium perfringens NCTC 8679 spores were demonstrated by increases in CFU after heating in water or aqueous alcohols. The temperature range for maximum activation, which was 70 to 80 degrees C in water, was lowered by the addition of alcohols. The response at a given temperature was dependent on the time of exposure and the
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17. Identification of the rph (RNase PH) gene of Bacillus subtilis: evidence for suppression of cold-sensitive mutations in Escherichia coli.
A shotgun cloning of Bacillus subtilis DNA into pBR322 yielded a 2-kb fragment that suppresses the cold-sensitive defect of the nusA10(Cs) Escherichia coli mutant. The responsible gene encodes an open reading frame that is greater than 50% identical at the amino acid level to the E. coli rph gene, which was formerly called orfE. This B. subtilis gene is loca
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18. Role of activation of protein kinase C in the stimulation of colonic epithelial proliferation and reactive oxygen formation by bile acids.
Deoxycholate (DOC), chenodeoxycholate, 12-O-tetradecanoyl phorbol-13-acetate (TPA), or 1-oleoyl-2-acetyl-glycerol (OAG) activated colonic epithelial protein kinase C as reflected by translocation from the soluble to the particulate cell fraction. Activation of protein kinase C was correlated with stimulation of enhanced proliferative activity of colonic muco
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19. Regulation of Pseudomonas aeruginosa chemotaxis by the nitrogen source.
The regulation of amino acid chemotaxis by nitrogen was investigated in the gram-negative bacterium Pseudomonas aeruginosa. The quantitative capillary tube technique was used to measure chemotactic responses of bacteria to spatial gradients of amino acids and other attractants. Chemotaxis toward serine, arginine, and alpha-aminoisobutyrate was sharply depend
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20. Analysis of the Escherichia coli nusA10(Cs) allele: relating nucleotide changes to phenotypes.
The Escherichia coli nusA gene product, known to influence transcription elongation, is essential for both bacterial viability and growth of lambdoid phages. We report the cloning and sequencing of the conditionally lethal nusA10(Cs) allele. Changes from nusA+ were observed at nucleotides 311 and 634. Functional studies showed that both nucleotide changes ar
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21. Rapid serogroup identification of Neisseria meningitidis by using antiserum agar: Prevalence of serotypes in a disease-free military population.
Nasopharyngeal cultures from 414 Marines were plated directly onto antiserum agar containing the antibiotics vancomycin, colistin, and nystatin for meningococcal isolation and serogroup identification. Meningococci were isolated from 267 Marines, giving a carrier prevalence of 64.5%. A total of 58% of the isolates could be placed into serogroups; of these 22
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22. Chemotaxis of Pseudomonas aeruginosa: involvement of methylation.
The involvement of a protein methyl transfer system in the chemotaxis of Pseudomonas aeruginosa was investigated. When a methionine auxotroph of P. aeruginosa was starved for methionine, chemotaxis toward serine, measured by a quantitative capillary assay, was reduced 80%, whereas background motility was unaffected or increased. When unstarved bacteria were
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23. Protein kinase C is activated in glomeruli from streptozotocin diabetic rats. Possible mediation by glucose.
Glomerular inositol content and the turnover of polyphosphoinositides was reduced by 58% in 1-2 wk streptozotocin diabetic rats. Addition of inositol to the incubation medium increased polyphosphoinositide turnover in glomeruli from diabetic rats to control values. Despite the reduction in inositol content and polyphosphoinositide turnover, protein kinase C
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24. Involvement of the Checkpoint Protein Mec1p in Silencing of Gene Expression at Telomeres in Saccharomyces cerevisiae
Yeast strains with a mutation in the MEC1 gene are deficient in the cellular checkpoint response to DNA-damaging agents and have short telomeres (K. B. Ritchie, J. C. Mallory, and T. D. Petes, Mol. Cell. Biol. 19:6065–6075, 1999; T. A. Weinert, G. L. Kiser, and L. H. Hartwell, Genes Dev. 8:652–665, 1994). In wild-type yeast cells, genes inserted near the
American Society for Microbiology.