SEARCH · Search PubMed

Results for “PSEUDOMONAS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

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

At least 73 records · Page 4Linked to original sources

PubMed1993

Increased expression of the plasmid-determined 2,3-dihydroxybiphenyl dioxygenase gene in strains of Escherichia coli, Pseudomonas putida and Pseudomonas aeruginosa.

A 6.5-kb EcoRI fragment containing the gene encoding 2,3-dihydroxybiphenyl dioxygenase from the plasmid pBS312 was cloned into broad host range plasmid RSF1010 and expressed in Escherichia coli, Pseudomonas putida and Pseudomonas aeruginosa strains. The increased expression of the gene was orientation-dependent and probably due to the transcription read through from the streptomycin promoter of the vector. Subcloning experiments of the PstI fragments of pBS312 plasmid using vector pBR322 revealed that the bphC gene encoding 2,3-dihydroxybiphenyl dioxygenase is localized on the 2.1-kb fragment. In Escherichia coli JM109, transformed by the plasmid pBS314 carrying the 2.1-kb insert in orientation which allowed expression of the bphC gene from the ampicillin promoter of pBR322, the enzyme activity of 2,3-dihydroxybiphenyl dioxygenase was ten times higher than that in parental strain Pseudomonas putida SU83. The results presented show the first case of the increased expression of Pseudomonas degradative gene in Escherichia coli.

Dioxygenases↗

PubMed1993

Analysis of the DNA damage-mediated induction of Pseudomonas putida and Pseudomonas aeruginosa lexA genes.

A fusion between the lexA gene of Pseudomonas aeruginosa and Pseudomonas putida and the lacZ gene was constructed in vitro and cloned in a mini-Tn5 transposon derivative to obtain chromosomal insertions which enable to quantitatively examine their transcriptional regulation in both Pseudomonas and E. coli. Analysis of DNA damage-mediated induction of these lexA-lacZ fusions showed that expression of P. putida and P. aeruginosa lexA genes was always higher and earlier than the expression of the lexA gene of E. coli. Furthermore, and in contrast to the lexA gene fusion of E. coli, the rates and extent of the induction of lexA gene fusion of P. putida and P. aeruginosa were largely independent of the UV doses applied. The behaviour of the lexA-lacZ fusions of two Pseudomonas species was the same regardless of whether they were inserted into their own chromosome or into E. coli.

Bacterial Proteins↗

PubMed1990

Inhibition of Pseudomonas aeruginosa elastase and Pseudomonas keratitis using a thiol-based peptide.

Pseudomonas aeruginosa elastase is a zinc metalloproteinase which is released during P. aeruginosa infections. Pseudomonas keratitis, which occurs following contact lens-induced corneal trauma, can lead to rapid, liquefactive necrosis of the cornea. This destruction has been attributed to the release of both host-derived enzymes and the bacterial products P. aeruginosa elastase, alkaline protease, exotoxin A, and lipopolysaccharide endotoxin. A synthetic metalloproteinase inhibitor, HSCH2 (DL)CH[CH2CH(CH3)2]CO-Phe-Ala-NH2, which we previously showed to be a potent inhibitor of corneal collagenase and alkali-induced corneal ulceration, was tested as a potential inhibitor of P. aeruginosa elastase. Inhibition constants (Kis) for the resolved diastereomers were determined with the chromogenic substrate furylacryloyl-glycyl-L-leucyl-L-alanine. One isomer had a Ki of 0.3 microM, while the other had a Ki of 0.4 microM. The more potent diastereomer was evaluated in vivo in experimentally induced Pseudomonas keratitis in rabbits. Following inoculation of one cornea of each rabbit, topical treatment with a 1 mM solution of the inhibitor significantly delayed the onset of corneal melting and perforation, as compared with the results for the control and gentamicin-treated groups. This protective effect suggests that the inhibitor may have a therapeutic application by delaying the progression of corneal destruction in Pseudomonas keratitis.

Amino Acid Sequence↗

PubMed1972

Contribution of humoral and cellular factors to the resistance to experimental infection by Pseudomonas aeruginosa in mice. II. Opsonic, agglutinative, and protective capacities of immunoglobulin G anti-Pseudomonas antibodies.

The opsonic, agglutinative, and mouse protective capacities of anti-Pseudomonas antibodies in immune and normal human immunoglobulin G (IgG) preparations were investigated. Opsonic activities of the immune IgG preparations correlated well with their protective activities. Antibodies present in normal IgG showed a substantial agglutinative activity but were poorly protective. Anti-Pseudomonas antibodies of both normal and immune IgG preparations were directed against the same serotype antigen as demonstrated by absorption experiments. Immune anti-Pseudomonas IgG antibodies fixed complement very efficiently as demonstrated by opsonophagocytic and hemolytic tests. Natural anti-Pseudomonas IgG antibodies fixed complement very poorly although they promoted phagocytic killing of bacteria only in the presence of heat-labile serum factors. It was concluded that, although agglutination can be used for qualitative measurement of antibacterial antibodies, it fails to measure their functional capacities.

Animals↗

PubMed1999

Influence of a putative ECF sigma factor on expression of the major outer membrane protein, OprF, in Pseudomonas aeruginosa and Pseudomonas fluorescens.

The gene encoding OprF, a major outer membrane protein in Pseudomonas species (formerly known as type 1 pseudomonads), was thought to be constitutively transcribed from a single sigma 70 promoter immediately upstream of the gene. We now report the identification of a novel putative ECF (extracytoplasmic function) sigma factor gene, sigX, located immediately upstream of oprF in both Pseudomonas aeruginosa PAO1 and Pseudomonas fluorescens OE 28.3 and show that disruption of this gene significantly reduces OprF expression. In P. aeruginosa, Northern analysis demonstrated that this reduction was a result of an effect on transcription of monocistronic oprF combined with a polar effect due to termination of a transcript containing sigX and oprF. Comparison of sigX-disrupted and wild-type cell transcripts by primer extension indicated that monocistronic transcription of oprF occurs from two overlapping promoters, one that is SigX-dependent and resembles ECF sigma factor promoters in its minus-35 region and another promoter that is independent of SigX and is analogous to the sigma 70-type promoter previously reported. Complementation of the P. aeruginosa sigX-disrupted mutant with plasmid-encoded OprF did not resolve the phenotypes associated with this mutant, which included a markedly reduced logarithmic-phase growth rate in rich medium (compared to that in minimal medium), further reduction of the growth rate in a low-osmolarity environment, secretion of an unidentified pigment, and increased sensitivity to the antibiotic imipenem. This indicates that SigX is involved in the regulation of other genes in P. aeruginosa. Disruption of the sigX gene in P. fluorescens also had an effect on the logarithmic-phase growth rate in rich medium. A conserved sigX gene was also identified in a Pseudomonas syringae isolate and six P. aeruginosa clinical isolates. Collectively, these data indicate that an ECF sigma factor plays a role in the regulation and expression of OprF and also affects other genes.

Bacterial Proteins↗

PubMedDate not supplied

Effects of antibiotics on adherence of Pseudomonas aeruginosa and Pseudomonas fluorescens to A549 pneumocyte cells.

The aim of this study was to evaluate the effect of antibiotics at subminimal inhibitory concentrations (sub-MIC) on fluorescent pseudomonas adherence to A549 pneumocyte cells. Pseudomonas fluorescens MF0 isolated from contaminated raw milk and Pseudomonas aeruginosa NK125502 isolated from a cystic fibrosis patient's lung adhered to A549 cells. As previously shown for P. aeruginosa, P. fluorescens bound to A549 cells in a dose-dependent manner over a wide range of bacterial concentrations. Bacterial growth in the presence of polymyxin B or gentamicin at MIC/2 had no effect on the adherence of NK125502 and MF0 to A549 cells. Instead, MIC/2 and MIC/8 of cefsulodin or chloramphenicol decreased the adherence of the two strains. A decrease in MF0 adherence was also observed with cefsulodin at MIC/32. We conclude that, in addition to their antibacterial activity, cefsulodin and chloramphenicol could be effective in preventing Pseudomonas adherence to respiratory epithelium.

Animals↗

PubMed1990

Inhibition of antibody response to Pseudomonas exotoxin and an immunotoxin containing Pseudomonas exotoxin by 15-deoxyspergualin in mice.

Immunotoxins are potent cell-killing agents that may be useful in the treatment of cancer. The early production of neutralizing antibodies to immunotoxins is one of the major limiting factors for their use in humans. 15-Deoxyspergualin (DSG), a derivative of spergualin, which is a metabolite of Bacillus laterosporus, has been found to have immunosuppressive activity in rodents, dogs, and primates. We examined the suppressive activity of DSG on the antibody response to Pseudomonas exotoxin in mice by enzyme-linked immunosorbent assay. Male BDF1 mice were immunized with a single dose of a nontoxic mutant of Pseudomonas exotoxin (40 micrograms) and then treated with i.p. injections of DSF at a dose of 10 mg/kg for 3 days. Although antibodies to Pseudomonas exotoxin were observed within 7 days in the control group, there was complete suppression of antibody production in the DSG-treated group. Immunosuppression has also been observed in animals immunized with multiple doses (10 mg x 7 d) of Pseudomonas exotoxin and treated with DSG at a dose of 5 mg/kg for 21 days. Similar immunosuppression was observed in mice given multiple doses of the immunotoxin, anti-Tac-LysPE40. We conclude that the immunosuppressive activity of DSG may be useful in increasing the duration of immunotoxin treatment.

ADP Ribose Transferases↗

PubMed1988

The estimation of usefulness of Pseudomonas bacteriophages in epidemiological investigations of Pseudomonas aeruginosa clinical strains.

Out of 20 Pseudomonas phages, 17 were most suitable for typing of Pseudomonas aeruginosa strains isolated from different sources of human infections. These phages have been classified into three taxons based on coefficient of correlation of their lytic activity. Out of these strains only one appeared nontypeable. 240 distinquished phagotypes were classified into three groups and seven subgroups. This schema of classification was used in the epidemiological investigations of the Pseudomonas strains in relation to the category of infection and the place of isolation. Some statisticaly significant differences were detected. Various possibilities of applications of typing set of Pseudomonas phages are discussed.

Bacteriophage Typing↗

PubMed1989

Enumeration of Pseudomonas species and Pseudomonas aeruginosa bacteriophages in domestic sewage.

Domestic sewage in Kuwait is mainly treated by an activated sludge process. Pseudomonas species were enumerated at all steps of sewage treatment. About 98-99% reduction in the number of these bacterial species were found in the treated effluent compared with raw sewage, which indicates a rather efficient removal of Pseudomonas from sewage. Spherical tail-less phages of Pseudomonas aeruginosa were found in all sewage samples. About 25-85% of the total phages encountered with the raw sewage were retained in the treated effluents. Seasonal variations of Pseudomonas spp and P. aeruginosa phages in two treatment stations are reported.

Bacteriophages↗

PubMed1987

[Role of Pseudomonas maltophilia and "Pseudomonas like bacteria group Va" in the etiology of Crohn disease].

In 1976, Parent and Mitchell isolated cell-wall defective bacteria of the species Pseudomonas maltophilia and Pseudomonas like bacteria group Va from resected bowel tissue of 8 consecutively operated patients with Crohn's disease. The control group, which included patients with ulcerative colitis, was negative in this respect. The isolated strains were available for our own investigations. New Zealand white rabbits were inoculated with killed bacteria to produce specific antisera. Frozen sections of affected tissue from 6 consecutively operated Crohn patients were incubated with the various antisera and investigated by indirect immunofluorescence. No positive reactions were demonstrable in repeated tests with different dilutions of antisera. Our results do not support the hypothesis that bacteria of the species Pseudomonas maltophilia and Pseudomonas like bacteria group Va are an etiologic factor in Crohn's disease.

Bacteriological Techniques↗

PubMedDate not supplied

[Identification of the bacterium Pseudomonas mallei using Pseudomonas pseudomallei bacteriophages].

Phage production by Pseudomonas pseudomallei and Pseudomonas mallei strains has been studied. 32 P. pseudomallei bacteriophages have been isolated. Their spectrum of lytic action against P. pseudomallei, P. mallei and other Pseudomonas sp. has been defined. It has been shown that P. pseudomallei bacteriophages PP19, PP23, PP33 may be used for identification P. mallei among related Pseudomonas.

Burkholderia pseudomallei↗

PubMed2001

Pseudomonas aeruginosa protease IV enzyme assays and comparison to other Pseudomonas proteases.

Pseudomonas aeruginosa secretes multiple proteases that have been implicated as virulence factors and the detection of each specific enzyme can be difficult to determine. Unlike the three Pseudomonas enzymes that have been well characterized (elastase A, elastase B, and alkaline protease), the activity of protease IV in multiple assays has yet to be described. This study defines new assays for Pseudomonas proteases and compares protease IV activity to the activities of elastase A, elastase B, and alkaline protease. Six in vitro assays were studied: zymography, elastin congo red assay, staphylolytic assay, colorimetric peptide assay, solid-phase colorimetric peptide assay, and poly-l-lysine degradation. Casein zymography distinguished protease IV from elastase B and alkaline protease, and gelatin zymography differentiated all four proteases. The elastin congo red assay detected mainly elastase B while the staphylolytic assay was specific for elastase A. Protease IV activity was assayed specifically by the colorimetric assay and two new assays, the solid-phase colorimetric assay and degradation of poly-L-lysine in the presence of EDTA. Alkaline protease could be specifically assayed by poly-L-lysine degradation in the presence of N-alpha-p-tosyl-L-lysine chloromethyl ketone. The results identified three specific assays for protease IV, a new assay specific for alkaline protease, and showed that protease IV has a distinct enzymatic specificity relative to the three other Pseudomonas proteases.

Colorimetry↗

PubMed1999

Substrate specificities of the chloromuconate cycloisomerases from Pseudomonas sp. B13, Ralstonia eutropha JMP134 and Pseudomonas sp. P51.

The chloromuconate cycloisomerase of Pseudomonas sp. B13 was purified from 3-chlorobenzoate-grown wild-type cells while the chloromuconate cycloisomerases of Ralstonia eutropha JMP134 (pJP4) and Pseudomonas sp. P51 (pP51) were purified from Escherichia coli strains expressing the corresponding gene. Kinetic studies were performed with various chloro-, fluoro-, and methylsubstituted cis,cis-muconates. 2,4-Dichloro-cis,cis-muconate proved to be the best substrate for all three chloromuconate cycloisomerases. Of the three enzymes, TfdD of Ralstonia eutropha JMP134 (pJP4) was most specific, since its specificity constant for 2,4-dichloro-cis,cis-muconate was the highest, while the constants for cis,cis-muconate, 2-chloro- and 2,5-dichloro-cis,cis-muconate were especially poor. The sequence of ClcB of the 3-chloro-benzoate-utilizing strain Pseudomonas sp. B13 was determined and turned out to be identical to that of the corresponding enzyme of pAC27 (though slightly different from the published sequences). Corresponding to 2-chloro-cis,cis-muconate being a major metabolite of 3-chlorobenzoate degradation, the kcat/K(m) with 2-chloro-cis,cis-muconate was relatively high, while that with the still preferred substrate 2,4-dichloro-cis,cis-muconate was relatively low. This enzyme was thus the least specific and the least active among the three compared enzymes. TcbD of Pseudomonas sp. P51 (pP51) took an intermediate position with respect to both the degree of specificity and the activity with the preferred substrate.

Bacterial Proteins↗

PubMed2001

Assignment of Pseudomonas sp. strain E-3 to Pseudomonas psychrophila sp. nov., a new facultatively psychrophilic bacterium.

A facultatively psychrophilic bacterium, previously described as Pseudomonas sp. strain E-3, has been reassigned by phenotypic characterization, chemotaxonomic analysis, DNA-DNA hybridization, and 16S rRNA gene phylogenetic analysis. The organism was a gram-negative, aerobic. straight rod with polar flagella. It was catalase positive and oxidase positive, able to grow at -1 degree C but not at 40 degree C, and produced acid from D-glucose under aerobic conditions. The major isoprenoid quinone was ubiquinone-9, and the DNA G + C content was 57.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that the bacterium is a member of the genus Pseudomonas and was closest to Pseudomonas fragi. Determination of the DNA-DNA relatedness between strain E-3 and P. fragi revealed too low a level of homology (47.9%-51.3%) to identify them as the same species. On the basis of phenotypic characteristics, phylogenetic analysis, and DNA-DNA relatedness data, it is concluded that strain E-3 represents an individual species. Accordingly, the name Pseudomonas psychrophila is proposed. The type strain is E-3T (= JCM 10889).

Base Composition↗

PubMed2003

A stable isotope dilution assay for the quantification of the Pseudomonas quinolone signal in Pseudomonas aeruginosa cultures.

A stable isotope dilution method was developed to analyse 2-heptyl-3,4-dihydroxyquinoline, also called the Pseudomonas quinolone signal (PQS), directly in Pseudomonas aeruginosa cultures by liquid chromatography coupled to mass spectrometry (LC/MS). PQS, along with the isobaric 2-heptyl-4-hydroxyquinoline N-oxide (HQNO), were quantified in various Pseudomonas liquid cultures using a deuterated PQS analog as internal standard. The kinetic of production of these quinolines in a growing culture of P. aeruginosa PA14 showed that their production starts at the end of the logarithmic growth phase and is maximal at the onset of the stationary growth phase. The concentration of PQS reached a maximum at 13 mg/l and then decreased, while the HQNO concentration reached 18 mg/l and then remained stable. Culture supernatants of P. aeruginosa strains PAO1 and PA14 produced similar concentrations of PQS whereas no PQS or HQNO could be detected in culture supernatants of the P. aeruginosa strain PAK or in the other Pseudomonas species tested, including phytopathogenic pseudomonads.

Hydroxyquinolines↗

PubMed1973

The formation of choline O-sulphate by Pseudomonas C12B and other Pseudomonas species.

Pseudomonas C(12)B and other Pseudomonas species released larger amounts of a (35)S-labelled metabolite into the medium when cultured on growth-limiting concentrations of Na(2)SO(4) as opposed to growth in SO(4) (2-)-sufficient media. The metabolite was found at all stages of the culture cycle of Pseudomonas C(12)B and maximum quantities occurred in stationary-phase culture supernatants. The metabolite was not detected when the bacterium was cultured on growth-limiting concentrations of potassium phosphate. The amount of the metabolite present in the medium greatly exceeded that which could be extracted from intact cells and, except for choline chloride, it was independent of the carbon source used for growth. If choline chloride was present in high concentration, then larger amounts of the metabolite were found in the culture medium. The metabolite was not detected extracellularly or intracellularly when the bacterium was grown in SO(4) (2-)-deficient media containing 5mm-l-cysteine. The same metabolite was also synthesized in vitro only when Pseudomonas C(12)B extracts were incubated with choline chloride, ATP, MgCl(2) and Na(2) (35)SO(4). The metabolite-forming system was not subject to repression by Na(2)SO(4) and was completely inhibited by 0.5mm-l-cysteine and activated by Na(2)SO(4) (up to 1.0mm). The metabolite was identified as choline O-sulphate by electrophoresis, chromatography and isotope-dilution analysis. Another (35)S-labelled metabolite was also detected in culture supernatants, but was not identified.

Acetates↗

PubMed1994

Classification of Pseudomonas diminuta Leifson and Hugh 1954 and Pseudomonas vesicularis Büsing, Döll, and Freytag 1953 in Brevundimonas gen. nov. as Brevundimonas diminuta comb. nov. and Brevundimonas vesicularis comb. nov., respectively.

The taxonomic positions of strains previously assigned to Pseudomonas diminuta and Pseudomonas vesicularis were investigated by a polyphasic approach. The results of DNA-rRNA hybridization studies indicated that these two species belong to a separate genus in the alpha subclass (rRNA superfamily IV) of the Proteobacteria, for which the name Brevundimonas is proposed. Genus delineation and species delineation were determined by comparing the results of numerical analyses of whole-cell protein patterns, fatty acid compositions, and phenotypic characteristics and by measuring DNA base ratios and degrees of DNA relatedness. Taxonomic characteristics of Brevundimonas diminuta and Brevundimonas vesicularis strains were compared with characteristics of reference strains belonging to the following phylogenetically related taxa: a group of organisms gathered in Enevold Falsen group 21, the genera Sphingomonas and Rhizomonas, and the generically misclassified organisms [Pseudomonas] echinoides and "[Pseudomonas] riboflavina."

Animals↗

PubMed2002

Pseudomonas salomonii sp. nov., pathogenic on garlic, and Pseudomonas palleroniana sp. nov., isolated from rice.

A total of 26 strains, including 15 strains isolated from garlic plants with the typical symptoms of 'Café au lait' disease and 11 strains isolated from diseased or healthy rice seeds and sheaths infested by Pseudomonas fuscovaginae, were compared with 70 type or reference strains of oxidase-positive pathogenic or non-pathogenic fluorescent pseudomonads. The strains were characterized by using a polyphasic taxonomic approach. Numerical taxonomy of phenotypic characteristics showed that the garlic and rice strains were related to each other. However, they clustered into separate phenons, distinct from those of the other strains tested, and were different in several nutritional tests. On the basis of DNA-DNA hybridization, the garlic and rice strains constituted two distinct DNA hybridization groups, indicating that they belonged to separate species. The two groups of strains were also well differentiated by siderotyping. Garlic strains were pathogenic to garlic plants and either weakly pathogenic or non-pathogenic on rice; rice strains were either weakly pathogenic or non-pathogenic on rice and non-pathogenic on garlic. A phylogenetic analysis of 16S rRNA gene sequences confirmed that the two groups of strains belonged to the y-Proteobacteria and to the genus Pseudomonas. The names Pseudomonas salomonii sp. nov. and Pseudomonas palleroniana sp. nov. are respectively proposed for the garlic strains and the rice strains. The type strains are P. salomonii CFBP 2022(T) ( = ICMP 14252(T) = NCPPB 4277(T)) and P. palleroniana CFBP 4389(T) (= ICMP 14253(T) = NCPPB 4278(T)).

Base Composition↗