Npn
Mostrando 37-45 de 45 artigos, teses e dissertações.
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37. Helicobacter pylori Uptake and Efflux: Basis for Intrinsic Susceptibility to Antibiotics In Vitro
We previously demonstrated (M. M. Exner, P. Doig, T. J. Trust, and R. E. W. Hancock, Infect. Immun. 63:1567–1572, 1995) that Helicobacter pylori has at least one nonspecific porin, HopE, which has a low abundance in the outer membrane but forms large channels. H. pylori is relatively susceptible to most antimicrobial agents but less susceptible to the poly
American Society for Microbiology.
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38. Brucella-Salmonella lipopolysaccharide chimeras are less permeable to hydrophobic probes and more sensitive to cationic peptides and EDTA than are their native Brucella sp. counterparts.
A rough (R) Brucella abortus 45/20 mutant was more sensitive to the bactericidal activity of polymyxin B and lactoferricin B than was its smooth (S) counterpart but considerably more resistant than Salmonella montevideo. The outer membrane (OM) and isolated lipopolysaccharide (LPS) of S. montevideo showed a higher affinity for these cationic peptides than di
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39. Mechanism of uptake of deglucoteicoplanin amide derivatives across outer membranes of Escherichia coli and Pseudomonas aeruginosa.
Teicoplanin is a glycopeptide antibiotic which is ineffective against gram-negative bacteria because of its inability to penetrate the outer membrane. Removal of the sugar residues and attachment of polyamines to carbon 63 yielded two dibasic deglucoteicoplanin amides, MDL 62,766 (766) and MDL 62,934 (934), with moderate MICs for Escherichia coli (2 to 4 mic
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40. Lymphocyte reactivity in patients with gonococcal urethritis.
Lymphocyte reactivity to virulent gonococcal antigen T2 and the non-pathogenic Neisseria pharyngis (NPN) has been studied by using the 14C-thymidine uptake in cell cultures from 42 patients with gonococcal urethritis and from 18 controls. The DNA synthesis in cell cultures with T2 antigen was higher in 21 female patients than in the 18 controls. No differenc
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41. Replication-defective ecotropic murine leukemia viruses: Detection and quantitation of infectivity using helper-dependent XC plaque formation.
Clones 8A and NP-N, which appear to be infected with replication-defective variants of murine leukemia virus, produce particles which do not form plques in the XC test. These particles formed XC plaques when amphotropic murine leukemia virus, which is XC negative, was added to the assay plates. This phenomenon can be used as a quantitiative infectivity assay
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42. Rescue and Transmission of a Replication-Defective Variant of Moloney Murine Leukemia Virus
We have described a clone of mouse cells, termed “8A,” which appears to be infected with a replication-defective variant of Moloney murine leukemia virus (MuLV) (Rein et al., J. Virol. 25:146-156, 1978). Clone 8A cells release virus particles which do not form plaques in the standard XC test. However, approximately 102 particles per ml of clone 8A supern
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43. Interaction of aminoglycosides with the outer membranes and purified lipopolysaccharide and OmpF porin of Escherichia coli.
The mechanism of uptake of aminoglycosides across the outer membrane of Escherichia coli was reevaluated. Porin-deficient mutants showed no alteration in gentamicin or kanamycin susceptibility. Furthermore, the influence of kanamycin on intrinsic tryptophan fluorescence of porin OmpF (Y. Kobayashi, and T. Nakae, Eur. J. Biochem. 151:231-236, 1985) was shown
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44. Transcriptional Analysis of Rickettsia prowazekii Invasion Gene Homolog (invA) during Host Cell Infection
An invasion gene homolog, invA, of Rickettsia prowazekii has recently been identified to encode a member of the Nudix hydrolase subfamily which acts specifically on dinucleoside oligophosphates (NpnN; n ≥ 5), a group of cellular signaling molecules known as alarmones. InvA is thought to enhance intracellular survival by regulating stress-induced toxic nucl
American Society for Microbiology.
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45. Intramolecular stacking association and conformation properties of a 'cap' structure, m7G5'pppUm, and the related model compounds.
The stacking equilibrium quotient of the m7G5'pppUm unit, which occurs as the 5'-terminal "cap" of certain eukaryotic mRNA's, was determined by temperature-dependent difference spectrophotometry as Kstack = 1.82 at 25 degrees and pH 5. In order to evaluate the contribution of different structural modifications to the net stabilization of the cap structures o