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PubMed1977

Experimental studies on the pathogenesis of infections due to Pseudomonas aeruginosa: direct evidence for toxin production during Pseudomonas infection of burned skin tissues.

Direct evidence is presented for the production of an exotoxin by Pseudomonas aeruginosa multiplying at the burned site in an infected mouse. Pseudomonas toxin was assayed by measurement of its ability to catalyze the transfer of radioactivity from [14C]adenine-labeled nicotinamide adenine dinucleotide to elongation factor 2 (adenosine diphosphate ribosylation activity). This enzyme activity was found in saline extracts of burned infected skin but was not present in similar extracts of burned uninfected skin. It was detected in the serum of infected animals by 26 hr after infection. The level of active elongation factor 2 in the livers of infected mice was reduced significantly after infection. These data suggest that pseudomonas exotoxin, produced by bacteria multiplying at the burn site, enters the circulation and is disseminated to different organs where it acts by depletion of elongation factor 2 and thus causes a reduction in protein synthesis.

Animals↗
PubMed1975

Transfer of antibiotic resistance plasmid RP1 into Pseudomonas glycinea and Pseudomonas phaseolicola in vitro and in planta.

The wide host-range antibiotic resistance plasmid RP1 was transferred from Pseudomonas aeruginosa via Escherichia coli into Pseudomonas glycinea. The plasmid was then acquired by Pseudomonas phaseolicla both in vitro and in planta in Phaseolus limensis leaves and pods. This was the first step in the design of a model system to determine the possible epidemiological significance of antibiotic resistance plasmids in the control of plant disease.

Acridines↗
PubMed1992

Derived amino acid sequences of the nosZ gene (respiratory N2O reductase) from Alcaligenes eutrophus, Pseudomonas aeruginosa and Pseudomonas stutzeri reveal potential copper-binding residues. Implications for the CuA site of N2O reductase and cytochrome-c oxidase.

The nosZ genes encoding the multicopper enzyme nitrous oxide reductase of Alcaligenes eutrophus H16 and the type strain of Pseudomonas aeruginosa were cloned and sequenced for structural comparison of their gene products with the homologous product of the nosZ gene from Pseudomonas stutzeri [Viebrock, A. & Zumft, W. G. (1988) J. Bacteriol. 170, 4658-4668] and the subunit II of cytochrome-c oxidase (COII). Both types of enzymes possess the CuA binding site. The nosZ genes were identified in cosmid libraries by hybridization with an internal 1.22-kb PstI fragment (NS220) of nosZ from P. stutzeri. The derived amino acid sequences indicate unprocessed gene products of 70084 Da (A. eutrophus) and 70695 Da (P. aeruginosa). The N-terminal sequences of the NosZ proteins have the characteristics of signal peptides for transport. A homologous domain, extending over at least 50 residues, is shared among the three derived NosZ sequences and the CuA binding region of 32 COII sequences. Only three out of nine cysteine residues of the NosZ protein (P. stutzeri) are invariant. Cys618 and Cys622 are assigned to a binuclear center, A, which is thought to represent the CuA site of NosZ and is located close to the C terminus. Two conserved histidines, one methionine, one aspartate, one valine and two aromatic residues are also part of the CuA consensus sequence, which is the domain homologous between the two enzymes. The CuA consensus sequence, however, lacks four strictly conserved residues present in all COII sequences. Cys165 is likely to be a ligand of a second binuclear center, Z, for which we assume mainly histidine coordination. Of 23 histidine residues in NosZ (P. stutzeri), 14 are invariant, 7 of which are in regions with a degree of conservation well above the 50% positional identity between the Alcaligenes and Pseudomonas sequences. Conserved tryptophan residues are located close to several potential copper ligands. Trp615 may contribute to the observed quenching of fluorescence when the CuA site is occupied.

Alcaligenes↗
PubMed1983

Cyanide production by Pseudomonas fluorescens and Pseudomonas aeruginosa.

Of 200 water isolates screened, five strains of Pseudomonas fluorescens and one strain of Pseudomonas aeruginosa were cyanogenic. Maximum cyanogenesis by two strains of P. fluorescens in a defined growth medium occurred at 25 to 30 degrees C over a pH range of 6.6 to 8.9. Cyanide production per cell was optimum at 300 mM phosphate. A linear relationship was observed between cyanogenesis and the log of iron concentration over a range of 3 to 300 microM. The maximum rate of cyanide production occurred during the transition from exponential to stationary growth phase. Radioactive tracer experiments with [1-14C]glycine and [2-14C]glycine demonstrated that the cyanide carbon originates from the number 2 carbon of glycine for both P. fluorescens and P. aeruginosa. Cyanide production was not observed in raw industrial wastewater or in sterile wastewater inoculated with pure cultures of cyanogenic Pseudomonas strains. Cyanide was produced when wastewater was amended by the addition of components of the defined growth medium.

Cyanides↗
PubMed1989

Growth of genetically engineered Pseudomonas aeruginosa and Pseudomonas putida in soil and rhizosphere.

The effect of the addition of a recombinant plasmid containing the pglA gene encoding an alpha-1,4-endopolygalacturonase from Pseudomonas solanacearum on the growth of Pseudomonas aeruginosa and Pseudomonas putida in soil and rhizosphere was determined. Despite a high level of polygalacturonase production by genetically engineered P. putida and P. aeruginosa, the results suggest that polygalacturonase production had little effect on the growth of these strains in soil or rhizosphere.

Genetic Engineering↗
PubMed2005

Conjugal TOL transfer from Pseudomonas putida to Pseudomonas aeruginosa: effects of restriction proficiency, toxicant exposure, cell density ratios, and conjugation detection method on observed transfer efficiencies.

The effects of restriction proficiency and premating exposure to toxicants on conjugal transfer of the TOL plasmid between Pseudomonas spp. was investigated by examinations of filter matings. A Pseudomonas putida KT2442-derived strain carrying a gfp-tagged variant of the TOL plasmid was used as a donor, and both restriction-deficient (PAO1162N) and -proficient (PAO2002N) Pseudomonas aeruginosa strains were used as recipients. The in situ enumeration of conjugation events allowed us to obtain frequency estimates that were unbiased by transconjugant growth or plasmid retransfer. We observed a strong dependence of the plasmid transfer frequency on the initial donor-to-recipient ratio of surface matings, which invalidated the use of mass action-based plasmid transfer kinetic estimators. Careful control of the initial parental cell densities permitted evaluations of the true effects of restriction proficiency and toxicant exposure on TOL transfer. At standard donor-to-recipient ratios (10(-3) for PAO1162N and 2 x 10(1) for PAO2002N) and total cell densities (10(5) cells/mm(2) for PAO1162N and 10(6) cells/mm(2) for PAO2002N), plasmid transfer frequencies without toxicant exposure were approximately 10(-7) (events/mm(2))(-1) for PAO1162N and 10(-11) (events/mm(2))(-1) for PAO2002N based on in situ observations of conjugation events. The enumeration of transconjugants via selective plating yielded transfer frequencies that were up to 1 order of magnitude lower. Premating exposure to sodium dodecyl sulfate (1 to 10 mM) significantly increased the transfer frequency for the restriction-proficient strain PAO2002N (P < 0.05) but not for the restriction-deficient strain PAO1162N. On the other hand, premating exposure to ethanol, toluene, or phenol had no positive effect on the plasmid transfer frequency. Clearly, restriction proficiency provides a strong barrier to interspecific transfer of the TOL plasmid, and this barrier was only marginally attenuated by recipient exposure to toxicants within the ranges examined.

Colony Count, Microbial↗
PubMed1984

Immunization with Pseudomonas aeruginosa high-molecular-weight polysaccharides prevents death from Pseudomonas burn infections in mice.

High-molecular-weight polysaccharides from the extracellular slime of Pseudomonas aeruginosa were evaluated as immunogens in Pseudomonas burn infections in mice. Immunization with immunotype 1 or 2 polysaccharides induced a strong immunotype-specific and weak cross-reactive antibody response but protected mice against burn infections caused by either immunotype. Passive protection was provided by rabbit antiserum to immunotype 1 polysaccharide against burn infection by the homologous organism. Pseudomonas high-molecular-weight polysaccharides are potentially effective vaccines in burn infections.

Animals↗
PubMed1989

Cross-reactivity of Pseudomonas aeruginosa antipilin monoclonal antibodies with heterogeneous strains of P. aeruginosa and Pseudomonas cepacia.

Much of the morbidity and mortality in patients with cystic fibrosis (CF) is secondary to pulmonary infections with Pseudomonas aeruginosa and, more recently, with Pseudomonas cepacia. Prevention of colonization and subsequent infection would be a useful therapeutic strategy. The pili (fimbriae) of P. aeruginosa are a potential vaccine antigen, as they have been implicated in binding to respiratory epithelium and appear to have limited antigenic diversity. Monoclonal antibodies (MAbs) raised to P. aeruginosa pilin demonstrated significant cross-reactivity, as four of five P. aeruginosa strains with known pilin sequences and 10 of 15 P. aeruginosa clinical isolates hybridized by immunoblot with at least one of the three MAbs tested. The P. cepacia strains demonstrated minimal cross-reactivity with these MAbs, as only 2 of 16 strains hybridized immunologically. The three MAbs decreased the adherence of 35S-labeled P. aeruginosa PA1244 to bovine tracheal cells by 56, 45, and 31%. One of these MAbs decreased the adherence of strains P. aeruginosa PAO1 and P. cepacia 249 to CF epithelial cells by 46 and 25%, respectively. While antibodies to Pseudomonas pili must be shown to be protective in patients with CF, these studies give support for a multivalent vaccine strategy using P. aeruginosa pilin as the immunogen.

Animals↗
PubMed1984

Use of ureidopenicillins for selection of plasmid vector transformants in Pseudomonas aeruginosa and Pseudomonas putida.

Broad-host-range plasmids coding for beta-lactamase were successfully selected after transformation of Pseudomonas strains. Transformants of both Pseudomonas aeruginosa and Pseudomonas putida containing plasmid pRO1614 were isolated in media containing low concentrations of piperacillin. These strains were also susceptible to other ureidopenicillins. Similar selections of transformants with carbenicillin, ampicillin, or ticarcillin required high concentrations of antibiotics and yielded backgrounds of spontaneous resistant mutants.

Ampicillin↗
PubMed1985

Cloning of genes specifying carbohydrate catabolism in Pseudomonas aeruginosa and Pseudomonas putida.

A 6.0-kilobase EcoRI fragment of the Pseudomonas aeruginosa PAO chromosome containing a cluster of genes specifying carbohydrate catabolism was cloned into the multicopy plasmid pRO1769. The vector contains a unique EcoRI site for cloning within a streptomycin resistance determinant and a selectable gene encoding gentamicin resistance. Mutants of P. aeruginosa PAO transformed with the chimeric plasmid pRO1816 regained the ability to grow on glucose, and the following deficiencies in enzyme or transport activities corresponding to the specific mutations were complemented: glcT1, glucose transport and periplasmic glucose-binding protein; glcK1, glucokinase; and edd-1, 6-phosphogluconate dehydratase. Two other carbohydrate catabolic markers that are cotransducible with glcT1 and edd-1 were not complemented by plasmid pRO1816: zwf-1, glucose-6-phosphate dehydrogenase; and eda-9001, 2-keto-3-deoxy-6-phosphogluconate aldolase. However, all five of these normally inducible activities were expressed at markedly elevated basal levels when transformed cells of prototrophic strain PAO1 were grown without carbohydrate inducer. Vector plasmid pRO1769 had no effect on the expression of these activities in transformed mutant or wild-type cells. Thus, the chromosomal insert in pRO1816 contains the edd and glcK structural genes, at least one gene (glcT) that is essential for expression of the glucose active transport system, and other loci that regulate the expression of the five clustered carbohydrate catabolic genes. The insert in pRO1816 also complemented the edd-1 mutation in a glucose-negative Pseudomonas putida mutant but not the eda-1 defect in another mutant. Moreover, pRO1816 caused the expression of high specific activities of glucokinase, an enzyme that is naturally lacking in these strains of Pseudomonas putida.

Aldehyde-Lyases↗
PubMed1991

RNA polymerases from Pseudomonas aeruginosa and Pseudomonas syringae respond to Escherichia coli activator proteins.

The activities of RNA polymerases (RNAPs) from Pseudomonas aeruginosa and Pseudomonas syringae were compared with that of Escherichia coli RNAP. All three enzymes are able to initiate transcription at the trpBA promoter of P. aeruginosa and at the coliphage lambda promoters, pRM and pRE, in response to heterospecific activators (TrpI protein, repressor, and cII protein, respectively). However, both Pseudomonas polymerases have less stringent requirements for promoter recognition in the absence of activators than does E. coli RNAP.

Bacterial Proteins↗
PubMed1992

Controlled study of Pseudomonas cepacia and Pseudomonas maltophilia in cystic fibrosis.

In a retrospective study, children with cystic fibrosis who were colonised with Pseudomonas cepacia were compared with a control group who were colonised with Pseudomonas maltophilia. Out of 216 children with cystic fibrosis seen between 1983 and 1990, P cepacia was recovered from 13 (median age at colonisation 12.2 years) and P maltophilia from 23 (median age at first colonisation 6.1 years), and both organisms were recovered in five cases. With the exception of two patients with P cepacia in whom no other pathogens were found, all the patients with P cepacia or P maltophilia had co-colonisation with Pseudomonas aeruginosa. The lack of spread of P cepacia to siblings with cystic fibrosis, and the relative lack of inpatient contact between colonised and uncolonised patients suggest that cross infection is not the sole route whereby patients with cystic fibrosis become infected, but the possibility of cross infection cannot be excluded from our data. Three patients with P cepacia died, but two of these had shown appreciable respiratory deterioration before colonisation with P cepacia; there was no evidence of unexpected deterioration in the remainder or in the controls with P maltophilia. By 1990, the prevalence of P cepacia was 9/133 (7%) and that of P maltophilia was 13/133 (10%), but it was impossible to determine to what extent this increase was due to the introduction of the routine use of selective media. Further studies are required to establish whether patients with and without P cepacia should be segregated.

Adolescent↗
PubMed2004

Pseudomonas keratitis: protease IV gene conservation, distribution, and production relative to virulence and other Pseudomonas proteases.

PURPOSE: To determine the distribution of the protease IV gene, the production of this and other proteases by multiple strains of Pseudomonas, and the virulence of a mutant specifically deficient in protease IV. METHODS: The protease IV gene was cloned, its sequence analyzed, and its chromosomal location determined by pulse-field gel electrophoresis. Three PCR reactions were used to detect the protease IV gene in 30 Pseudomonas isolates and protease production was determined by Western blot analysis, colorimetric assay, and zymography. An allelic replacement mutant deficient in the protease IV gene was analyzed for enzyme production, corneal growth, and corneal virulence. RESULTS: The protease IV gene was identified in all P. aeruginosa, but none of the non-aeruginosa strains tested. The protease IV genes of strains PA103-29 and PAO1 were in a common chromosomal site and had 98.5% sequence identity with variations occurring mainly in the promoter region. The protease IV activity of the 23 wild-type P. aeruginosa strains tested varied from 2.3 to 221.5 x 10(-3) U/mg protein in the culture supernatant. Protease IV was produced by all P. aeruginosa wild-type strains. A protease IV-deficient mutant derived from strain PA103-29 had reduced virulence compared with its parent strain and unexpectedly produced alkaline protease. CONCLUSIONS: The protease IV gene and its product are common to P. aeruginosa, but not to other Pseudomonas species. Protease IV activity varies among P. aeruginosa strains, and a mutant specifically deficient in this activity produced alkaline protease and had reduced corneal virulence.

Amino Acid Sequence↗
PubMedDate not supplied

[Mechanism of cyanide and thiocyanate decomposition by an association of Pseudomonas putida and Pseudomonas stutzeri strains].

The intermediate and terminal products of cyanide and thiocyanate decomposition by individual strains of the genus Pseudomonas, P. putida strain 21 and P. stutzeri strain 18, and by their association were analyzed. The activity of the enzymes of nitrogen and sulfur metabolism in these strains was compared with that of the collection strains P. putida VKM B-2187T and P. stutzeri VKM B-975T. Upon the introduction of CN- and SCN- into cell suspensions of strains 18 and 21 in phosphate buffer (pH 8.8), the production of NH4+ was observed. Due to the high rate of their utilization, NH3, NH4+, and CNO- were absent from the culture liquids of P. putida strain 21 and P. stutzeri strain 18 grown with CN- or SCN-. Both Pseudomonas strains decomposed SCN- via cyanate production. The cyanase activity was 0.75 micromol/(min mg protein) for P. putida strain 21 and 1.26 micromol/(min mg protein) for P. stutzeri strain 18. The cyanase activity was present in the cells grown with SCN- but absent in cells grown with NH4+. Strain 21 of P. putida was a more active CN- decomposer than strain 18 of P. stutzeri. Ammonium and CO2 were the terminal nitrogen and carbon products of CN- and SCN- decomposition. The terminal sulfur products of SCN- decomposition by P. stutzeri strain 18 and P. putida strain 21 were thiosulfate and tetrathionate, respectively. The strains utilized the toxic compounds in the anabolism only, as sources of nitrogen (CN- and SCN-) and sulfur (SCN-). The pathway of thiocyanate decomposition by the association of bacteria of the genus Pseudomonas is proposed based on the results obtained.

Ammonia↗
PubMed1993

[Effect of the use of human hyperimmune plasma against Pseudomonas protein for protection against Pseudomonas sepsis in burn mice].

A controlled study was performed to evaluate the efficacy of human hyperimmune plasma (HIP) for protecting burned mice from Pseudomonas infection. The HIP was prepared from healthy volunteers immunized with endotoxin protein (Ep) of Pseudomonas aeruginosa. It contained antibody against Ep up to the titre higher than 1:128. Mice with full-thickness burn of 13% TBSA, infected by subeschar injection of 0.2 ml P. aeruginosa (CFU/ml), were treated with HIP at 6 hrs and 18 hrs postburn. The survival rate of the former on the 7th day was 45%, while in mice treated with normal plasma (NP) was 14% and in control mice 10% (P < 0.01). If the HIP was given 18h after burn, the survival rate was 43%, while in mice with NP was 39% and in control 42% (P > 0.05). The results indicate that HIP is able to protect burned mice from Pseudomonas infection giving at 6 hrs postburn (pre sepsis) but not at 18 hrs postburn (post sepsis).

Animals↗
PubMed1984

Verapamil enhances the toxicity of conjugates of epidermal growth factor with Pseudomonas exotoxin and antitransferrin receptor with Pseudomonas exotoxin.

Verapamil, a clinically important calcium channel blocker, has been found to cause a 40-fold enhancement of killing of the human KB cell line by a cytotoxic conjugate of epidermal growth factor with Pseudomonas exotoxin (EGF-PE). Synergistic effects of verapamil and EGF-PE are also seen on HeLa D98 cells and a human epidermal carcinoma cell line, A431. Verapamil also potentiates the effect of a toxic conjugate formed between Pseudomonas exotoxin and a monoclonal antibody to the human transferrin receptor (anti-TFR-PE) and enhances the effect of Pseudomonas exotoxin (PE) alone. Two other calcium antagonists were tested. Diltiazem enhances the cytotoxic effect of EGF-PE, but nifedipine does not. Verapamil does not affect the binding and uptake of 125I-EGF by KB cells, but it significantly delays the disappearance of internalized 125I-EGF from the cells. Density gradient fractionation studies using cell homogenates suggest that 125I-EGF accumulates in an undegraded form in lysosomes when cells are treated with verapamil. By immunofluorescence microscopy using an antibody to PE, EGF-PE was found to accumulate in lysosomes; by electron microscopy the lysosomes had an abnormal appearance. The effects of verapamil on toxicity of EGF-PE and lysosomal function appear to be related. However, it is not known whether the enhanced toxicity of EGF-PE in the presence of verapamil is due to its delayed degradation in lysosomes or some more general effect of verapamil on membrane permeability.

ADP Ribose Transferases↗
PubMed2003

Comparison of aspartate transcarbamoylase regulation in Pseudomonas alcaligenes and Pseudomonas mendocina.

The regulation of aspartate transcarbamoylase activity in cell extracts of Pseudomonas alcaligenes ATCC 14909 and Pseudomonas mendocina ATCC 25411 was compared. Under saturating substrate concentrations, pyrophosphate, CTP, UDP and ADP were highly inhibitory of the P. alcaligenes transcarbamoylase activity while pyrophosphate, UDP, ADP, ATP and GTP were the most effective inhibitors of the P. mendocina transcarbamoylase. By examining transcarbamoylase inhibition by ribonucleotide triphosphates, it was possible to differentiate these species assigned to different DNA homology groups and such an analysis might prove useful in the reclassification of Pseudomonas species.

Aspartate Carbamoyltransferase↗