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At least 343 records · Page 19Linked to original sources
PubMed1992

Genetic and functional analysis of the basic replicon of pPS10, a plasmid specific for Pseudomonas isolated from Pseudomonas syringae patovar savastanoi.

The sequence of a 1823 base-pair region containing the replication functions of pPS10, a narrow host-range plasmid isolated from a strain of Pseudomonas savastanoi, is reported. The origin of replication, oriV, or pPS10 is contained in a 535 base-pair fragment of this sequence that can replicate in the presence of trans-acting function(s) of the plasmid. oriV contains four iterons of 22 base-pairs that are preceded by G+C-rich and A+T-rich regions. A dnaA box located adjacent to the repeats of the origin is dispensable but required for efficient replication of pPS10; A and T are equivalent bases at the 5' end of the box. repA, the gene of a trans-acting replication protein of 26,700 Mr has been identified by genetic and functional analysis. repA is adjacent to the origin of replication and is preceded by the consensus sequences of a typical sigma 70 promoter of Escherichia coli. The RepA protein has been identified, using the minicell system of E. coli, as a polypeptide with an apparent molecular mass of 26,000. A minimal pPS10 replicon has been defined to a continuous 1267 base-pair region of pPS10 that includes the oriV and repA sequences.

Amino Acid Sequence↗
PubMed1995

Genes encoding RubisCO in Pseudomonas hydrogenothermophila are followed by a novel cbbQ gene similar to nirQ of the denitrification gene cluster from Pseudomonas species.

The cbbL and cbbS genes, encoding ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), were cloned and sequenced from a thermophilic hydrogen-oxidizing bacterium, Pseudomonas hydrogenothermophila strain TH-1. The cbbL gene encoded a 474-amino-acid (aa) protein (53,285 Da); cbbS encoded a 124-aa protein (14,656 Da). An ORF found downstream from the cbbLS genes encoded a 267-aa protein (29,565 Da) which had no similarity to cbbX located downstream from cbbLS from Alcaligenes eutrophus and Xanthobacter flavus. This gene, called cbbQ, was highly similar to the nirQ gene of the denitrification gene cluster from P. aeruginosa and P. stutzeri.

Alcaligenes↗
PubMed1994

Construction of improved Escherichia-Pseudomonas shuttle vectors derived from pUC18/19 and sequence of the region required for their replication in Pseudomonas aeruginosa.

The nucleotide sequence of the 1.9-kb PstI fragment from pRO1614, that allows stable maintenance of pMB1 (ColE1)-based cloning vectors in Pseudomonas, was determined. This fragment encodes a putative origin of replication (ori), a replication-controlling protein, and the C terminus of the Tn3 beta-lactamase-encoding gene. Improved versions of the broad-host-range plasmid vectors, pUCP18 and pUCP19, were constructed by deletion of nonessential DNA or replacement of nonessential DNA with an antibiotic-resistance cassette.

Amino Acid Sequence↗
PubMedDate not supplied

Basic fibroblast growth factor-Pseudomonas exotoxin chimeric proteins; comparison with acidic fibroblast growth factor-Pseudomonas exotoxin.

We have constructed growth factor-toxin chimeric molecules composed of basic fibroblast growth factor (bFGF) and two different binding mutant forms of Pseudomonas exotoxin termed bFGF-PE40 and bFGF-PE4E KDEL. The chimeric molecules were expressed in Escherichia coli and localized to both inclusion bodies and the spheroplast cytoplasm. The bFGF-toxin fusion protein that was isolated and purified from inclusion bodies was 3-fold more active in inhibiting protein synthesis than that purified from spheroplast cytoplasm. Immunoreactivity of purified bFGF-toxin fusion protein to anti-bFGF antibodies was similar to that of native bFGF, as determined by ELISA analysis. A variety of carcinoma cell lines were sensitive to bFGF-PE40 and bFGF-PE4E KDEL, including H3396 (breast), Hep G2 (hepatocellular), and A431 (epidermoid). The concentration of chimeric toxin that inhibited protein synthesis by 50% (EC50) was 110, 70, and 18 ng/mL for bFGF-PE40 and 15, 1, and 18 ng/mL for bFGF-PE4E KDEL. In comparison with fusion-toxins composed of acidic fibroblast growth factor (aFGF) and either PE40 or PE4EKDEL, bFGF-PE40 and bFGF-PE4E KDEL were similarly cytotoxic on most cell lines tested. Human aortic smooth muscle cells were sensitive to both bFGF and aFGF toxin fusion proteins. However, human aortic endothelial cells were sensitive to the bFGF-toxins but were resistant to both aFGF-toxin forms. Time course studies showed that bFGF-PE40 needed a 4-6-h exposure to target cells for peak inhibition of protein synthesis on both MCF-7 and A431 cells, while aFGF-PE40 was almost fully active within a 2-h incubation.(ABSTRACT TRUNCATED AT 250 WORDS)

ADP Ribose Transferases↗
PubMed2000

Alkaline proteinase inhibitor of Pseudomonas aeruginosa. Interaction of native and N-terminally truncated inhibitor proteins with Pseudomonas metalloproteinases.

The apr locus of Pseudomonas aeruginosa encodes alkaline proteinase (APR), a member of the metzincin metalloendopeptidase superfamily, and an 11.4-kDa alkaline proteinase inhibitor (APRin). We describe here the expression in Escherichia coli and characterization of full-length and N-terminally truncated APRin proteins. Fluorescence and circular dichroism spectra indicated that the recombinant proteins were folded into native-like structures. Analytical ultracentrifugation showed that APRin was monomeric and formed a 1:1 complex with APR. Binding of wild-type APRin to APR occurred with association (k(on)) and dissociation (k(off)) rate constants of 0.29 +/- 0.06 x 10(6) m(-1) s(-1) and 1.15 +/- 0.08 x 10(-6) s(-1) to give an equilibrium dissociation constant (K(D)) of approximately 4 x 10(-12) m (25 degrees C, pH 7.0, ionic strength 2.4 m). The association rate decreased by approximately 2-fold in 20% glycerol and increased by approximately 3-fold in 0.1 m NaCl. The glycerol effect suggests a diffusion-limited reaction, and the small salt effect indicates that electrostatic interactions contribute little to binding. Deletion of residues 1-10, 1-6, or 6-10 abolished inhibition, and deletion of residues 1-2, 1-3, 1-4, and 1-5 resulted in a progressively decreased affinity of APRin for APR (K(D) = 0.12 micrometer the Delta(1-5) mutant). Substitution of APRin residues 6-10 with a (Gly)(5) or (Pro)(5) linker restored inhibitory activity of the Delta(6-10) mutant but with a 100- and 50-fold reduction in K(D). Log k(on) for the full-length and truncated inhibitors correlated with the solvent-accessible surface area of their N-terminal regions, suggesting that increased interactions and/or desolvation of these residues in the transition state for binding contribute to the enhanced association rate. Treatment of APRin with pseudolysin, also secreted by P. aeruginosa, resulted in removal of residues 1-5. APRin was neither an inhibitor nor a substrate of other metzincins, including collagenase or gelatinases A or B.

Alkaline Phosphatase↗
PubMed1995

Recovery of Pseudomonas cepacia and other Pseudomonas species from the environment.

Nine hundred sixteen cultures were obtained from homes of patients with cystic fibrosis, control homes, salad bars, and food markets, and analyzed for the presence of Pseudomonas cepacia and related bacteria. P cepacia was recovered from 5 (18%) of 27 homes, and from 20 (4%) of 509 cultures collected outside of homes. Relative to other pseudomonads, P cepacia is found infrequently in the environment. It is not clear how frequently these sources contribute to acquisition of this bacteria by persons with cystic fibrosis.

Bacteriological Techniques↗
PubMed2001

Introduction of the phzH gene of Pseudomonas chlororaphis PCL1391 extends the range of biocontrol ability of phenazine-1-carboxylic acid-producing Pseudomonas spp. strains.

Pseudomonas chlororaphis PCL1391 controls tomato foot and root rot caused by Fusarium oxysporum f. sp. radicis-lycopersici. Its biocontrol activity is mediated by the production of phenazine-1-carboxamide (PCN). In contrast, the take-all biocontrol strains P. fluorescens 2-79 and P. aureofaciens 30-84, which produce phenazine-1-carboxylic acid (PCA), do not control this disease. To determine the role of the amide group in biocontrol, the PCN biosynthetic genes of strain PCL1391 were identified and characterized. Downstream of phzA through phzG, the novel phenazine biosynthetic gene phzH was identified and shown to be required for the presence of the 1-carboxamide group of PCN because a phzH mutant of strain PCL1391 accumulated PCA. The deduced PhzH protein shows homology with asparagine synthetases that belong to the class II glutamine amidotransferases, indicating that the conversion of PCA to PCN occurs via a transamidase reaction catalyzed by PhzH. Mutation of phzH caused loss of biocontrol activity, showing that the 1-carboxamide group of PCN is crucial for control of tomato foot and root rot. PCN production and biocontrol activity of the mutant were restored by complementing the phzH gene in trans. Moreover, transfer of phzH under control of the tac promoter to the PCA-producing biocontrol strains P. fluorescens 2-79 and P. aureofaciens 30-84 enabled these strains to produce PCN instead of PCA and suppress tomato foot and root rot. Thus, we have shown, for what we believe is the first time, that the introduction of a single gene can efficiently extend the range of the biocontrol ability of bacterial strains.

Amino Acid Sequence↗
PubMed2000

Utility of internally transcribed 16S-23S rDNA spacer regions for the definition of Pseudomonas stutzeri genomovars and other Pseudomonas species.

Bacteria identified and classified as Pseudomonas stutzeri, on the basis of traditional criteria, are recognized to be markedly heterogeneous, such that a systematic phenotypic characterization has not been correlated with genotypic groupings (i.e. genomovars) based upon DNA-DNA similarities. The internally transcribed 16S-23S rDNA spacer (ITS1) regions of P. stutzeri were analysed with respect to the ability of these nucleic acid regions to differentiate and identify the genomic groups (i.e. genomovars) of P. stutzeri. The ITS1s of 34 strains of P. stutzeri were amplified by PCR and the PCR product was subjected to RFLP analysis, which allowed the differentiation and identification of the strains to their respective genomovars. Sequence determination and analysis of ITS1s supported further the results obtained by RFLP, i.e. nucleotide signatures were identified in strains belonging to different genomovars. The ITS1s of all strains of P. stutzeri contained the tandem tRNA(Ile)/tRNA(Ala) genes and did not exhibit distinct sequence heterogeneity between different operons of a strain. Phylogenetically informative variable sites were located, exclusively, in non-coding regions. The results of the RFLP and sequence analysis of ITS1s supported and correlated with the phylogenetic relationships estimated from 16S rRNA gene sequence comparisons and DNA-DNA hybridizations, offering an alternative tool for genomovar and species differentiation.

DNA, Bacterial↗
PubMed1986

An investigation of three commercial methods for rapid identification of non-enteric gram-negative rods. Application on Pseudomonas paucimobilis and some other Pseudomonas species.

Three commercial systems for the identification of non-enteric gram-negative rods were compared with conventional bacteriological methods as reference. The three systems were the API 20 NE, BIO-TEST ID-Trident, and ROSCO Diagnostic Tablets. The systems were tested on a set of 47 strains from the genus Pseudomonas, with the emphasis upon the yellow-pigmented species. The overall identification accuracy was 97% with the API, 19% with the BIOTEST and 68% with the ROSCO system. The API system was thus reliable, and it presented no major practical problems. The BIOTEST system was very handy. The main reason for the low accuracy was an error in the code book. The ONPG reaction was depicted as negative in the species P. paucimobilis. A positive ONPG test is a keymark in this species and 76% of the 20 strains of P. paucimobilis included in this investigation were also found positive with the BIOTEST system. The ROSCO tablets are convenient if the result of single reactions is desired. The time consumption per strain was 5.4, 4.4, and 6.2 min for the API, BIOTEST, and ROSCO systems respectively.

Predictive Value of Tests↗
PubMed1983

Transfer of plasmids from Escherichia coli to Pseudomonas aeruginosa: characterization of a Pseudomonas aeruginosa mutant with enhanced recipient ability for enterobacterial plasmids.

Pseudomonas aeruginosa strain GT424, derived by the transfer of plasmid R45 to strain GT1, was shown to have an Era+ phenotype (enhanced recipient ability) for enterobacterial plasmids from incompatibility (Inc) groups C, FI, FII, J, N, W, and X. Increase in transfer frequency ranged from 10 to 10(6)-fold. Plasmids of IncFII, IncJ, and IncX were found to be transmissible only to the Era+ strain. Plasmids of Inc groups A-C, M, and T transferred at low frequency (less than 10(-7)) to both GT1 and GT424 and did not respond to the Era+ character of the latter. Also not responsive to the Era character were plasmids R144drd3 (IncI alpha) and RP1 (IncP), which transferred to both GT424 and GT1 at intermediate (10(-4)) and high frequencies (10(-1)), respectively. All plasmid-mediated antibiotic resistances that could be measured as well as UV resistance and susceptibility were found to be expressed in P. aeruginosa. Plasmid-coded phage susceptibilities, however, generally were not phenotypically manifested in the P. aeruginosa strains. The physical structure of plasmids in P. aeruginosa could be classified into four major types. Some of the plasmids underwent additions or deletions and were unstable; the majority, however, appeared to integrate into the chromosome. Some members of IncN, IncC, IncJ, and IncP were found to be transmissible from P. aeruginosa back to Escherichia coli. This is the first report of the successful transfer to P. aeruginosa of plasmids from many of the Inc groups that have been defined in Enterobacteriaceae, namely, FI, I alpha, J, M, T, and X.

Conjugation, Genetic↗
PubMed1999

Pseudomonas aeruginosa: a survey of resistance in 136 hospitals in Spain. The Spanish Pseudomonas aeruginosa Study Group.

We carried out a nationwide study with all of the isolates of Pseudomonas aeruginosa collected in a week in 136 hospitals in Spain. The data on 1,014 isolates included resistance to the following antimicrobials: piperacillin-tazobactam, 7%; meropenem, 8%; amikacin, 9%; tobramycin, 10%; piperacillin, 10%; ticarcillin, 13%; imipenem, 14%; ceftazidime, 15%; cefepime, 17%; ciprofloxacin, 23%; aztreonam, 23%; ofloxacin, 30%; gentamicin, 31%. The most frequent serotypes were O:1 (25.1%), O:4 (21.6%), and O:11 (11.3%).

Anti-Bacterial Agents↗
PubMed1975

Penicillin-resistant mechanisms in Pseudomonas aeruginosa: binding of penicillin to Pseudomonas aeruginosa KM 338.

A comparison of the binding of radioactive penicillin G to whole cells and the membrane fraction derived from Pseudomonas aeruginosa KM 338 was made. This organism has intrinsic resistance to penicillin. The binding to the membrane fraction which catalyzed peptidoglycan synthesis followed saturation type kinetics and saturation was achieved at approximately 2 nmol of penicillin G per ml, whereas binding to the whole cells was entirely of the nonsaturation type. The binding of carbenicillin to the membrane fraction was determined by competition between radioactive penicillin G and unlabeled carbenicillin for the binding sites. It was bound at the same sites in almost the same manner. When whole cells were pretreated with high concentration of unlabeled penicillin G or carbenicillin, the subsequent binding of radioactive penicillin G to the membrane fraction from carbenicillin-treated cells was entirely nonspecific, but with penicillin G-pretreated cells it was still specific. There was apparently specific binding of radioactive penicillin G to ethylenediaminetetraacetate-treated cells. P. aeruginosa KM 338 had an extremely low activity of beta-lactamase compared with other enzyme-producing organisms. This enzyme from P. aeruginosa KM 338 was of the cephalosporinase type. These data indicate that penicillin resistance of P. aeruginosa KM 338 may be a consequence of the development of a permeability barrier which prevents the antibiotic from reaching its sites of action in the cytoplasmic membrane.

Penicillin G↗
PubMed1971

Resistance of Pseudomonas to quaternary ammonium compounds. II. Cross-resistance characteristics of a mutant of Pseudomonas aeruginosa.

Tube dilution experiments showed that benzalkonium chloride (BC)-resistant mutants of Pseudomonas aeruginosa grown in the presence of 1,000 mug of BC per ml were at least 20 times more sensitive to polymyxin B and colistin sulfate than the BC-sensitive (BCS) parent strain. BCS cells selected for resistance to 500 mug of polymyxin B per ml remained sensitive to BC. There was little difference in the amount of carbenicillin, gentamicin sulfate, or rifampin needed to prevent growth of either the BCS or BC-resistant (BCR) strains. Growth of BCR cells was inhibited by ethylenediaminetetraacetate at a concentration of 400 mug/ml or less, whereas the BCS strain grew at ethylenediaminetetraacetate levels of 10,000 mug/ml. Phenylmercuric acetate and thimerosal inhibited growth of BCR and BCS cells at concentrations of 10 mug/ml or less. BCR cells were cross-resistant to >1,000 mug/ml concentrations of five other quaternary ammonium compounds, including three with C(16) alkyls and two with alkyl groups of shorter length. The BCS strain was also resistant to >1,000 mug/ml concentrations of the three quaternary ammonium compounds with C(16) alkyl groups but, in addition to BC, was inhibited by 200 mug/ml levels or less of the two quaternary ammonium compounds containing alkyl groups of less than 16 carbon atoms.

Anti-Bacterial Agents↗
PubMed1983

Virulence of different Pseudomonas species in a burned mouse model: tissue colonization by Pseudomonas cepacia.

The virulence of Pseudomonas aeruginosa and other pseudomonads was examined in a burned mouse model. P. aeruginosa M-2 was highly virulent causing 100% mortality by 38 h with an injection of 10(2) CFU by either a subcutaneous or intraperitoneal route. Subcutaneous injection of 10(2) CFU revealed rapid multiplication of the bacteria at the burn wound with 10(8) CFU/g detectable in the burned skin by 28 h postinjection, 10(5) CFU/g of liver, and 10(3) CFU/ml of blood. Non-P. aeruginosa clinical isolates were markedly less virulent; an injection of greater than or equal to 10(7) CFU caused less than or equal to 60% lethality. P. cepacia SMH colonized the burned skin of thermally injured mice, persisting at levels of 10(7) to 10(8) CFU/g of burned skin after an initial injection of 10(5) CFU. P. cepacia persisted in the burn wound for at least 3 weeks. No organ invasion was detectable throughout this period. Studies with an additional clinical isolate of P. cepacia yielded similar results. An injection of a 10(2) CFU dose revealed that the level of persistence is dose dependent. Results suggest that the tenacious persistence of P. cepacia in the burn wound may provide a model for the study of persistent colonization and infection in a compromised host.

Animals↗
PubMed1985

Suppression of lymphocyte proliferation by Pseudomonas aeruginosa: mediation by Pseudomonas-activated suppressor monocytes.

Pseudomonas aeruginosa has been shown to suppress cell-mediated immunity in experimental animals, but recent reports have also demonstrated that there is a strong T-cell response to this bacteria. Our studies of human peripheral blood mononuclear cells showed a great variation in the in vitro proliferative response to killed P. aeruginosa, so we examined the interaction of the different mononuclear cells in cultures with this bacteria. P. aeruginosa stimulated the proliferation of T lymphocytes, specifically the surface-immunoglobulin-negative, T8- subset, which are felt to be T helper cells. P. aeruginosa added in coculture experiments to peripheral blood mononuclear cells stimulated with Staphylococcus aureus, Streptococcus pyogenes, or tetanus toxoid suppressed the proliferation to these latter antigens. This proliferation was not affected by the depletion of adherent monocytes from peripheral blood mononuclear cells, and the suppression was restored when monocytes were added back to these cultures. Moreover, monocytes pulsed with P. aeruginosa but not with S. aureus suppressed the antigen-induced proliferation of peripheral blood mononuclear cells. This monocyte suppression was not inhibited by indomethacin and was unlikely to be the result of prostaglandin synthesis by these cells. Thus, P. aeruginosa can induce monocytes to suppress antigen-stimulated T-lymphocyte proliferation in vitro, and these suppressor cells may facilitate the growth of this organism in disorders such as cystic fibrosis.

Adult↗
PubMed1971

Comparative zone electrophoresis of enzymes of Pseudomonas solanacearum and Pseudomonas cepacia.

The technique of starch-gel electrophoresis with specific staining for a series of enzymes was used to compare 21 Pseudomonas strains representing both P. cepacia and P. solanacearum. These experiments produced no evidence for close similarity of the two species. Twelve strains of P. solanacearum were compared by means of data obtained from nine different enzymes, and the data indicate that these strains belong in two biotypes. Except for the assignment of two strains, these groups are the same as the two major groups previously derived from nutritional properties and from deoxyribonucleic acid hybridization experiments. Eleven enzymes were available for comparisons of the P. cepacia strains. Eight of these strains form a homogeneous group, but the last strain, number 249, differs considerably from the other representatives of the species.

Alcohol Oxidoreductases↗