SEARCH · PubMed Health

Results for “PSEUDOMONAS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources

PubMed1975

Alternative routes of aromatic catabolism in Pseudomonas acidovorans and Pseudomonas putida: gallic acid as a substrate and inhibitor of dioxygenases.

When 3,4-dihydroxyphenylacetic acid (homoprotocatechuic acid) was added to Pseudomonase acidovorans growing at the expense of succinate, enzymes required for degrading homoprotocatechuate to pyruvate and succinate semialdehyde were strongly induced. These enzymes were effectively absent from cell extracts of the organism grown with 4-hydroxyphenylacetic acid, and this substrate was metabolized by the catabolic enzymes of the homogentisate pathway. Two separate ring-fission dioxygenases for 3,4,5-trihydroxybenzoic acid (gallic acid) were present in cell extracts of Pseudomonas putida when grown with syringic acid, and gallate was degraded by reactions associated with meta fission. One of the two gallate dioxygenases also attacked 3-O-methylgallic acid; the other, which did not, was induced when cells were exposed to gallate. This organism possessed ortho fission enzymes, including protocatechuate 3,4-dioxygenase (EC 1.13.11.3) and cis,cis-carboxymuconate-lactonizing enzyme (EC 5.5.1.2), after induction with 3,4-dihydroxybenzoic acid (protocatechuic acid). Gallate was a substrate for protocatechuate 3,4-dioxygenase, with a Vmax about 3% of that of protocatechuate and with an apparent Km slightly lower. Gallate was a powerful competitive inhibitor of protocatechuate oxidation.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1985

Cloning of Escherichia coli and Pseudomonas aeruginosa phosphomannose isomerase genes and their expression in alginate-negative mutants of Pseudomonas aeruginosa.

The phosphomannose isomerase (pmi) gene of Escherichia coli was cloned on a broad-host-range cosmid vector and expressed in Pseudomonas aeruginosa at a low level. Plasmid pAD3, which harbors the E. coli pmi gene, contains a 6.2-kilobase-pair HindIII fragment derived from the chromosome of E. coli. Subcloning produced plasmids carrying the 1.5-kilobase-pair HindIII-HpaI subfragment of pAD3 that restored alginic acid production in a nonmucoid, alginate-negative mutant of P. aeruginosa. This fragment also complemented mannose-negative, phosphomannose isomerase-negative mutants of E. coli and showed no homology by DNA-DNA hybridization to P. aeruginosa chromosomal DNA. By using a BamHI constructed cosmid clone bank of the stable alginate producing strain 8830, we have been able to isolate a recombinant plasmid of P. aeruginosa origin that also restores alginate production in the alginate-negative mutant. This new recombinant plasmid, designated pAD4, contained a 9.9-kilobase-pair EcoRI-BamHI fragment with the ability to restore alginate synthesis in the alginate-negative P. aeruginosa. This fragment showed no homology to E. coli chromosomal DNA or to plasmid pAD3. Both mucoid and nonmucoid strains of P. aeruginosa had no detectable levels of phosphomannose isomerase activity as measured by mannose 6-phosphate-to-fructose 6-phosphate conversion. However, P. aeruginosa strains harboring the cloned pmi gene of E. coli contained measurable levels of phosphomannose isomerase activity as evidenced by examining the conversion of mannose 6-phosphate to fructose 6-phosphate.

Alginates↗

PubMed1989

Degradation of phenol and m-toluate in Pseudomonas sp. strain EST1001 and its Pseudomonas putida transconjugants is determined by a multiplasmid system.

The utilization of phenol, m-toluate, and salicylate (Phe+, mTol+, and Sal+ characters, respectively) in Pseudomonas sp. strain EST1001 is determined by the coordinated expression of genes placed in different plasmids, i.e., by a multiplasmid system. The natural multiplasmid strain EST1001 is phenotypically unstable. In its Phe-, mTol-, and Sal- segregants, the plasmid DNA underwent structural rearrangements without a marked loss of plasmid DNA, and the majority of segregants gave revertants. The genes specifying the degradation of phenol and m-toluate were transferable to P. putida PaW340, and in this strain a new multiplasmid system with definite structural changes was formed. The 17-kilobase transposable element, a part of the TOL plasmid pWWO present in the chromosome of PaW340, was inserted into the plasmid DNA in transconjugants. In addition, transconjugant EST1020 shared pWWO-like structures. Enzyme assays demonstrated that ortho-fission reactions were used by bacteria that grew on phenol, whereas m-toluate was catabolized by a meta-fission reaction. Salicylate was a functional inducer of the enzymes of both pathways. The expression of silent metabolic pathways of phenol or m-toluate degradation has been observed in EST1001 Phe- mTol+ and Phe+ mTol- transconjugants. The switchover of phenol degradation from the ortho- to the meta-pathway in EST1033 also showed the flexibility of genetic material in EST1001 transconjugants.

Benzoates↗

PubMed1991

Cloning, sequence, and expression of a lipase gene from Pseudomonas cepacia: lipase production in heterologous hosts requires two Pseudomonas genes.

The lipA gene encoding an extracellular lipase from Pseudomonas cepacia was cloned and sequenced. Downstream from the lipase gene an open reading frame was identified, and the corresponding gene was named limA. lipA was well expressed only in the presence of limA. limA exerts its effect both in cis and in trans and therefore produces a diffusible gene product, presumably a protein of 344 amino acids. Replacement of the lipA expression signals (promoter, ribosome-binding site, and signal peptide-coding sequences) by heterologous signals from gram-positive bacteria still resulted in limA-dependent lipA expression in Escherichia coli, Bacillus subtilis, and Streptomyces lividans.

Amino Acid Sequence↗

PubMed1991

Cloning of a catabolite repression control (crc) gene from Pseudomonas aeruginosa, expression of the gene in Escherichia coli, and identification of the gene product in Pseudomonas aeruginosa.

Mutants which are defective in catabolite repression control (CRC) of multiple independently regulated catabolic pathways have been previously described. The mutations were mapped at 11 min on the Pseudomonas aeruginosa chromosome and designated crc. This report describes the cloning of a gene which restores normal CRC to these Crc- mutants in trans. The gene expressing this CRC activity was subcloned on a 2-kb piece of DNA. When this 2-kb fragment was placed in a plasmid behind a phage T7 promoter and transcribed by T7 RNA polymerase, a soluble protein with a molecular weight (MW) of about 30,000 was produced in Escherichia coli. A soluble protein of identical size was overproduced in a Crc- mutant when it contained the 2-kb fragment on a multicopy plasmid. This protein could not be detected in the mutant containing the vector without the 2-kb insert or with no plasmid. When a 0.3-kb AccI fragment was removed from the crc gene and replaced with a kanamycin resistance cassette, the interrupted crc gene no longer restored CRC to the mutant, and the mutant containing the interrupted gene no longer overproduced the 30,000-MW protein. Pools of intracellular cyclic AMP and the activities of adenylate cyclase and phosphodiesterase were measured in mutant and wild-type strains with and without a plasmid containing the crc gene. No consistent differences between any strains were found in any case. These results provide original evidence for a 30,000-MW protein encoded by crc+ that is required for wild-type CRC in P. aeruginosa and confirms earlier reports that the mode of CRC is cyclic AMP independent in this bacterium.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1992

Comparison of the Sceptor Pseudomonas Plus MIC Panel with agar dilution for susceptibility testing of Pseudomonas aeruginosa.

The antimicrobial susceptibilities of 100 clinical isolates of Pseudomonas aeruginosa to gentamicin, amikacin, tobramycin, ticarcillin, piperacillin, and ceftazidime were determined by using the Sceptor system (BBL Microbiology Systems, Cockeysville, Md.), and the results were compared with those obtained using the National Committee for Clinical Laboratory Standards reference agar dilution method. Excellent correlation was observed for the aminoglycosides, with greater than 95% agreement within 1 doubling dilution of the reference agar dilution MIC, while ticarcillin and piperacillin showed lower percent agreement values of 91 and 88%, respectively.

Anti-Bacterial Agents↗

PubMed1998

Emergence of multidrug resistance in ubiquitous and dominant Pseudomonas aeruginosa serogroup O:11. The Greek Pseudomonas Aeruginosa Study Group.

The serotypes of 88 nonreplicate nosocomial Pseudomonas aeruginosa isolates from 11 Greek hospitals were studied in relation to their antibiotic susceptibilities. Rates of resistance to beta-lactams, aminoglycosides, and quinolones ranged from 31 to 65%, except for those to ceftazidime (15%) and imipenem (21%). Four serotypes were dominant: O:12 (25% of isolates), O:1 (17%), O:11 (16%), and O:6 (10%). Multidrug resistance rates in the major serogroups O:12 (91%) and O:11 (79%) were higher than those in serogroups O:1 (40%) and O:6 (43%). Further typing with respect to pulsed-field gel electrophoresis patterns following XbaI digestion of genomic DNA discriminated the isolates into 74 types. Pulsed-field gel electrophoresis revealed that the ubiquitous O:12 group was genetically homogeneous, since 95% of strains belonged to two clusters of genotypic similarity, while the O:11 strains, present in 8 of the 11 hospitals, were distributed among five such clusters. Therefore, apart from the already reported O:12 multidrug-resistant European clone, an O:11 population, characterized by a serotype known to be dominant in the environment and the hospital in several parts of the world, but previously not associated with multidrug resistance to antibiotics, has progressed to a multidrug-resistant state.

DNA Fingerprinting↗

PubMed1999

Recombinant Pseudomonas exoenzyme S and exoenzyme S from Pseudomonas aeruginosa DG1 share the ability to stimulate T lymphocyte proliferation.

Exoenzyme S from P. aeruginosa DG1 and recombinant exoenzyme S derived from strain 388 have distinct characteristics, which has led to a controversy about their homology and their pathophysiologic consequences. We have been investigating the ability of exoenzyme S to activate T lymphocytes, and therefore performed studies to determine whether exoenzyme S from P. aeruginosa DG1 and recombinant exoenzyme S derived from strain 388 and expressed in Pseudomonas aeruginosa PA103 or in E. coli BL21(DE3), could induce T lymphocyte activation and proliferation. Both preparations were able to activate T cells and induce lymphocyte proliferation at similar levels as measured by flow cytometry of surface-activation markers and DNA synthesis, respectively. Further, a monoclonal antibody raised against exoenzyme S from strain DG1 partially neutralized T cell activation induced by recombinant exoenzyme S and bound to it in an immunoblot suggesting that the epitope responsible for T cell activation is shared by exoenzyme S from strain DG1 and recombinant exoenzyme S. These data suggest that the two different preparations of exoenzyme S, despite biochemical differences, share the characteristic that is responsible for T lymphocyte activation.

ADP Ribose Transferases↗

PubMed1978

L-forms of Pseudomonas aeruginosa. 3. The serological cross-reactions among stable L-forms of Pseudomonas aeruginosa, L-form of Streptococcus pyogenes and mycoplasmas.

The serological cross-reactions among stable L-forms of Pseudomonas aeruginosa, or of Streptococcus pyogenes and mycoplasmas were investigated in passive hemagglutination (PHA) and agar gel diffusion tests. (1) PHA active fraction which reacts most strongly with homologous serum was obtained from the sodium dodecyl sulfate soluble fraction of L-form membrane after disruption by Braun cell homogenizer. (2) Antiserum prepared against L-forms in rabbits showed high-level stimulation of PHA antibodies, while it showed little stimulation of agglutinating antibodies. (3) In PHA and agar gel diffusion tests, antiserum to L-form of P. aeruginosa strain IFO-3,455 reacted with L-form of strain N-10, which is serologically different in serotype from strain IFO-3,455. Furthermore, the two L-forms of P. aeruginosa cross-reacted with a L-form of S. pyogenes. 4) L-forms of P. aeruginosa and S. pyogenes did not react with five strains of mycoplasmas in PHA and agar gel diffusion tests.

Antigens, Bacterial↗

PubMed1992

Iron metabolism in Pseudomonas: salicylic acid, a siderophore of Pseudomonas fluorescens CHAO.

Under iron-starvation conditions of growth, Pseudomonas fluorescens CHA0, a soil isolate involved in phytopathogenic fungi antagonisms, produced, together with pyoverdine, a second iron-chelating compound which was purified and identified by spectroscopy, HPLC and 1H-NMR to be salicylic acid. Mutants unable to synthesize pyoverdine overproduced this compound by a factor of 9-14. The biosynthesis of salicylic acid was under iron control; it was fully inhibited by 5 microM added iron in the growth medium. In contrast, salicylic acid of either bacterial or commercial origin facilitated labeled iron incorporation in iron-starved cells. Based on these two relationships observed with bacterial iron metabolism it is concluded that salicylic acid has a siderophore function for this strain.

Iron↗

PubMed1992

[Cloning the trpBA-genes from Pseudomonas mendocina and Pseudomonas marginata].

The trpBA genes of Pseudomonas mendocina and P. marginata were cloned in Escherichia coli using pBR322 as a vector. Transcription of the cloned genes took place from their own promoters, in the following order: trpB-->trpA. The latter genes were not linked to the trpF gene and could not be induced by indole glycerol phosphate. Thus, the trpBA cluster of P. mendocina and P. marginata are distinguished from that of P. putida, P. aeruginosa (trpIBA) and P. acidovorans (trpFBA).

Cloning, Molecular↗

PubMedDate not supplied

[Utilization by Escherichia coli and Pseudomonas fluorescens of a siderophore from Pseudomonas fluorescens strain PAB].

Pseudomonas fluorescens PAB strain produced pyoverdine in a synthetic medium. Pigment was purified by solvent extraction and ion exchange, and sterilized and used as siderophore for E. coli, P. fluorescens, ATCC 13.525, ATCC 17.400, W and PAB strains. Bacteria were grown in iron-free medium and medium with iron. Free--pyoverdine and pyoverdine bound to Fe+3 were added in different concentrations. P. fluorescens PAB siderophore did not stimulate E. coli growth while it was selective for other P. fluorescens strains. Paper disks impregnated with pyoverdine did not inhibit E. coli growth.

Escherichia coli↗

PubMed1975

Study of Pseudomonas haemolysin. II. Characteristics of Pseudomonas haemolysin.

Haemolysins of 4 strains of Pseudomonas aeruginosa producing different fractions [II, 2 + II, I + II + III] were studied. The production of specific antibodies was demonstrated making possible the immunoelectrophoretic record of the whole lysin and of the individual fractions. Tests on laboratory animals [mice, rabbits] showed a high degree lethal and dermonecrotic property of the lysin containing the fractions II + III and I + II + III.

Absorption↗

PubMedDate not supplied

[The lipopolysaccharides of Pseudomonas solanacearum i Pseudomonas cichorii].

Structure analysis by the methods of methylation, 1H- and 13C-n. m. r. spectroscopy has shown that O-specific polysaccharides of typical strains of Pseudomonas solanacearum (biovar I) and P. cichorii are identical by their structure and constructed of branched pentasaccharide repeating links which include three residues of rhamnose (one of them is in the branching node), one residue of beta-xylose (it occupies terminal position) and one reside of N-acetyl-beta-glucosamine. The other strain of P. solanacearum of biovar I and two strains belonging to biovars III and IV also produce structure-similar O-specific polysaccharides, constructed of linear tetrasaccharide repeating links which include three residues of alpha-L-rhamnose and one residue of N-acetyl-alpha-D-glucosamine.

Lipopolysaccharides↗

PubMed1987

Controlled and functional expression of the Pseudomonas oleovorans alkane utilizing system in Pseudomonas putida and Escherichia coli.

The OCT plasmid encodes enzymes for alkane hydroxylation and alkanol dehydrogenation. Structural components are encoded on the 7.5-kilobase pair alkBAC operon, whereas positive regulatory components are encoded by alkR. We have constructed plasmids containing fusions of cloned alkBAC and alkR DNA and used these fusion plasmids to study the functional expression of the alkBAC operon and the regulatory locus alkR in Pseudomonas putida and in Escherichia coli. Growth on alkanes requires a functional chromosomally encoded fatty acid degradation system in addition to the plasmid-borne alk system. While such a system is active in P. putida, it is active in E. coli only in fadR mutants in which fatty acid degradation enzymes are expressed constitutively. Using such mutants, we found that E. coli as well as P. putida grew on octane as the sole source of carbon and energy when they were supplied with the cloned complete alk system. The alkR locus was strictly necessary in E. coli as well as in P. putida for expression of the alkBAC operon. The alkBAC operon could, however, be further reduced to a 5-kilobase pair operon without affecting the Alk phenotype in either species to a significant extent. Although with this reduction the plasmid-encoded alkanol dehydrogenase activity was lost, chromosomally encoded alkanol dehydrogenases in P. putida and E. coli compensated for this loss. The induction kinetics of the alk system was studied in detail in P. putida and E. coli. We used specific antibodies raised against alkane hydroxylase to follow the appearance of this protein following induction with octane. We found the induction kinetics of alkane hydroxylase to be similar in both species. A steady-state level was reached after about 2 h of induction in which time the alkane hydroxylase accounted for about 1.5% of total newly synthesized protein. Thus, alkBAC expression is very efficient and strictly regulated to both P. putida and E. coli.

Alkanes↗

PubMed1988

[Compatibility of transposable phages of Escherichia coli and Pseudomonas aeruginosa. I. Co-development of phages Mu and D3112 and integration of phage D3112 into RP4::Mu plasmid in Pseudomonas aeruginosa cells].

The possibility of using a model system (which included RP4::Mu plasmid and D3112 phage in Pseudomonas aeruginosa cells) for analysis of compatibility of transposable Escherichia coli phage Mu and P. aeruginosa phage D3112, as phages and transposons, was studied. No interaction was observed during the vegetative growth of phages. The majority of the hybrid RP4::Mu plasmids lost the Mu DNA after insertion of D3112 into RP4::Mu. The phenomenon was not a result of transposition immunity. We consider the loss of the Mu DNA as a consequence either of plasmid RP4::Mu instability in P. aeruginosa cells, because of the lack of functional Mu repressor, or of some D3112-encoded activity involved in its transposition. For the inambiguous conclusion on compatibility of two phages as transposons, it is necessary to modify the model system, eliminating the possibility of Mu phage replication--transposition.

Bacteriophages↗

PubMed1988

Mutational analysis of domain I of Pseudomonas exotoxin. Mutations in domain I of Pseudomonas exotoxin which reduce cell binding and animal toxicity.

Pseudomonas exotoxin (PE) is a single polypeptide chain that contains 613 amino acids and is arranged into three structural domains. Domain I is responsible for cell recognition, II for translocation of PE across membranes and III for ADP ribosylation of elongation factor 2. Treatment of PE with reagents that react with lysine residues has been shown to lead to a reduction in cytotoxic activity apparently due to a modification of domain I (Pirker, R., FitzGerald, D. J. P., Hamilton, T. C., Ozols, R. F., Willingham, M. C., and Pastan, S. (1985) Cancer Res. 45, 751-757). To determine which lysine residues are important in cell recognition, all 12 lysines in domain I were converted to glutamates by site-directed mutagenesis. Also, two deletion mutants encompassing almost all of domain I (amino acids 4-252) or most of domain I (amino acids 4-224) were studied. The mutant proteins were produced in Escherichia coli, purified, and tested for their cytotoxic activity against Swiss 3T3 cells and in mice. The data indicate that conversion of lysine 57 to glutamate reduces cytotoxic activity towards 3T3 cells 50-100-fold and in mice about 5-fold. Deletion of amino acids 4-224 causes a similar reduction in toxicity towards cells and mice. Deletion of most of the rest of domain I (amino acids 4-252) causes a further reduction in toxicity toward cells and mice indicating this second region between amino acids 225 and 252 of domain I is also important in the toxicity of PE. Competition assays indicated that the ability of PEGlu57 to bind to 3T3 cells was greatly diminished, accounting for its diminished cytotoxic activity.

ADP Ribose Transferases↗

PubMed1986

[Value of bactericidal curves in the optimal selection of a beta-lactam-aminoglycoside combination on Pseudomonas aeruginosa. In vitro study of 40 strains of Pseudomonas aeruginosa isolated in pediatric intensive care units].

Antimicrobial sensitivity and time-kill curves were determined for ticarcillin, azlocillin, piperacillin, cefsulodin, ceftazidime, gentamicin, tobramycin and amikacin alone or in combination against 40 strains of Pseudomonas aeruginosa isolated from blood cultures and tracheal aspirates in pediatric intensive care units. The antibiotics were used in concentrations obtainable with the usual therapeutic dosage. No bactericidal effect was observed with each of the beta-lactam antibiotics tested alone. For ticarcillin-sensitive strains the most rapid bacterial inoculum size decrease was observed at 2.5 h with the piperacillin-amikacin combination, and a bactericidal effect was obtained within 4.5 h when amikacin was combined with ticarcillin, azlocillin, piperacillin, ceftazidime or cefsulodin. For ticarcillin-resistant strains a bactericidal effect was obtained within 4.5 h when amikacin was combined with piperacillin, azlocillin, ceftazidime or cefsulodin.

Amikacin↗