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PubMed1982

Management of Pseudomonas osteochondritis complicating puncture wounds of the foot.

Pseudomonas osteochondritis following puncture wounds of the foot is described in 13 children. All children had received at least one oral antibiotic and local wound therapy before admission; none had improved on these modalities. Pseudomonas aeruginosa was isolated alone from seven patients and with one or more other organisms from six patients. Initial administration of parenteral antibiotics active against Pseudomonas for one to 14 days did not result in clinical improvement. Eradication of Pseudomonas osteochondritis occurred in each patient only after thorough surgical debridement and curettage of all infected tissue. Following thorough surgical debridement, anti-Pseudomonas antibiotic therapy was continued for five to 14 days (10.8 +/- 2.7 days). The successful treatment of Pseudomonas osteochondritis should include adequate surgical debridement of all infected tissue; following thorough debridement, only one to two weeks of anti-Pseudomonas antibiotic therapy appears to be necessary.

Adolescent↗
PubMed1981

Infections with Pseudomonas aeruginosa in the compromised host.

A review is given of the role of the various host defences in man against Pseudomonas aeruginosa and the mechanisms by which these are compromised in certain patient categories especially susceptible to serious Pseudomonas infections. The defects of host defences are usually complex and multiple, affecting various sites in the local and the systemic defences. Certain defects are emphasized, e.g. abnormalities of first line defences (skin, mucous membranes), and both quantitative and qualitative defects in polymorphonuclear granulocytes. However, it is also suggested that compromised functions of other components of antimicrobial defences may play a role in Pseudomonas infections, e.g. functional abnormalities in the systems of B cells. T cells and mononuclear phagocytes. Recent data suggesting mechanisms by which P. aeruginosa can exert suppressive effects on host defences, are mentioned, and the possibility of immunopathogenesis in Pseudomonas infections is discussed, particularly processes involving the complement system. Some important clinical features of Pseudomonas infections are described. The clinical peculiarities of bacterial infections in the severely neutropenic patient are emphasized, and exemplified with a brief description of Pseudomonas pneumonia. Finally, Pseudomonas septicaemia is mentioned with a brief discussion of certain important prognostic factors. It is concluded that a better understanding of the complex defense mechanisms against P. aeruginosa and therapeutic regimens by which they can be manipulated, is imperative to achieve any significant advances in the prevention and treatment of these infections.

Antibody Formation↗
PubMed1989

[The significance of bacterial and host factors in corneal infections caused by Pseudomonas aeruginosa].

Two pathogenic mechanisms are discussed as possibly being responsible for destruction of the corneal tissue in the course and corneal infections caused by Pseudomonas aeruginosa. One involves bacterial exoenzymes and the other polymorphonuclear (PNM)-derived lysosomal enzymes. The objective of the present study was (1) to show the relative importance of the two mechanisms and (2) to evaluate the effect of active immunization against Pseudomonas aeruginosa exoenzymes on ocular damage. Rabbits were immunized against Pseudomonas aeruginosa alkaline protease (AP) or elastase (Ela) and challenged with the respective enzymes. Corneal damage was studied by light photography. In another group rabbits were immunized against AP, Ela and exotoxine A and challenged with Pseudomonas aeruginosa strain PA 01 und PA 103. Corneal damage was studied by light photography, light microscopy and electron microscopy. Immunized animals were totally protected against purified Pseudomonas aeruginosa exoenzymes. Less corneal damage was found in immunized rabbits than in non-immunized ones. 12 and 24 h after infection with whole bacteria. However, after 48 h corneal damage was comparable in both groups. These results show that corneal damage by lysosomal enzymes from stimulated PMN ist more important in Pseudomonas aeruginosa than direct damage by bacterial exoenzymes.

ADP Ribose Transferases↗
PubMed1985

Development of broad-host-range vectors for expression of cloned genes in Pseudomonas.

The cloning and expression of genes in Pseudomonas have been difficult, until now, due to the absence of vector systems that contain multiple restriction sites downstream from promoter sequences that are functional in Pseudomonas. We report here the construction of several broad-host-range vectors that can be utilized in either Pseudomonas or Escherichia coli and that rely on easily selectable antibiotic resistance markers with multiple cloning sites. These vectors were constructed by inserting the entire pUC13 sequence into derivatives of the RSF1010 wide-host-range plasmid. From this construction, other derivatives were obtained, specifically a lacZ::KmR fusion gene which provides an easily selectable marker in both E. coli and Pseudomonas. These vectors have been used to express the Pseudomonas putida cytochrome P450 monoxygenase gene in a P450-deficient P. putida strain. Thus, these vectors allow for the cloning, expression and selection of Pseudomonas genes in Pseudomonas by complementation.

Amino Acid Sequence↗
PubMed2002

Multiple enzyme restriction fragment length polymorphism analysis for high resolution distinction of Pseudomonas (sensu stricto) 16S rRNA genes.

Members of the genus Pseudomonas (sensu stricto) are important phytopathogens and agents of human infections, while other strains and species have beneficial bioremediation and biocontrol activities. Traditionally, these important species have been difficult to differentiate phenotypically; thus, rRNA lineage analyses have often been invoked. In this report, a newly developed approach is described to rapidly detect and distinguish fluorescent Pseudomonas isolates: PCR amplification of a Pseudomonas-specific 990-bp ribosomal RNA gene (rDNA) fragment [Appl. Environ. Microbiol. 64 (1998) 2545.] coupled with multiple enzyme restriction fragment length polymorphism (MERFLP) analysis using a single digestion mixture of AluI, HinfI, RsaI, and Tru9I incubated at 37 degrees C. The method distinguished 116 published sequences and 47 reference strains of authentic Pseudomonas representing 28 nomenspecies. A total of 55% (64/116) of the sequences analyzed by MERFLP were grouped into distinct phylogenetic clusters including Pseudomonas putida, P. syringae, P. aeruginosa, P. stutzeri, and P. fluorescens. The utility of the MERFLPs was confirmed when 100% (33/33) of the above named control reference strains were correctly placed into their phylogenetic clusters. The environmental relevance of the MERFLP method was confirmed when 67% of 28 forest and agricultural soil-derived presumptive Pseudomonas environmental clones and isolates were placed into the five major pseudomonad clusters, one clone fell into the P. agarici cluster, and five clones clustered near related pseudomonads. These data demonstrated that the PCR-MERFLP protocol provides an efficient and powerful tool for distinguishing isolates and rDNA gene libraries of environmental Pseudomonas species.

Bacterial Typing Techniques↗
PubMed1973

Cleavage of malyl-Coenzyme A into acetyl-Coenzyme A and glyoxylate by Pseudomonas AM1 and other C1-unit-utilizing bacteria.

1. Malyl-CoA lyase was found in high activity in extracts of Pseudomonas AM1, Pseudomonas MA, Pseudomonas MS, Hyphomicrobium X and Methylosinus trichosporium. 2. The enzyme cleaves (2S)-malyl-CoA into equimolar amounts of acetyl-CoA and glyoxylate in the presence of Mg(2+). 3. The specific activity of malyl-CoA lyase was several-fold higher in Pseudomonas AM1 when grown on C(1) compounds than when grown on C(2), C(3) or C(4) compounds. This suggests that the enzyme plays a specially important role in C(1) metabolism. 4. It is suggested that its role in C(1) metabolism, in organisms utilizing the serine pathway, is to provide the glyoxylate necessary to sustain operation of this pathway. 5. The activity of malyl-CoA lyase in extracts of Pseudomonas MA, Pseudomonas MS and Hyphomicrobium X is 27-50 times higher than the activity of ATP- and CoA-dependent cleavage of malate, suggesting that the latter activity may be due to coupling of two enzymes, malate thiokinase and malyl-CoA lyase. 6. Methane-grown Pseudomonas methanica and Methylococcus capsulatus, which are not known to use the serine pathway, possess appreciable amounts of malyl-CoA lyase. Instead of being used primarily for carbon assimilation, the enzyme may here serve as a route to glycine during biosynthesis of purines and proteins.

Acetyl Coenzyme A↗
PubMed1975

The microbial metabolism of C1 compounds. The electron-transport chain of Pseudomonas am1.

Pseudomonas AM1, Hyphomicrobium X and Pseudomonas MS all contain cytochrome a/a(3) and a b-type cytochrome able to react with CO. Pseudomonas AM1 and Hyphomicrobium X also have a CO-binding cytochrome c. The purified cytochrome c (redox potential 0.26V) of Pseudomonas AM1 was not susceptible to oxidation by molecular oxygen. CO reacted slowly with the reduced form giving a CO difference spectrum with a peak at 412nm and troughs at 420nm and 550nm. Similar results were obtained with the cytochrome c of Hyphomicrobium (aerobically grown or anaerobically grown with nitrate) and with that of Pseudomonas extorquens. The results given in the present paper are incompatible with an oxygenase or oxidase function for the soluble cytochrome c of methylotrophs. Studies with whole cells of Pseudomonas AM1 and a cytochrome c-deficient mutant have demonstrated that cytochrome b (redox potential 0.009V) is the first cytochrome in the electron-transport chain for oxidation of all substrates except methanol (and ethanol) whose oxidation does not involve this cytochrome. All substrates are usually oxidized by way of cytochrome c and cytochrome oxidase (cytochrome a/a(3)), but there is an alternative route for the reduction of cytochrome a/a(3) in the mutant lacking cytochrome c. Results of experiments on cyanide inhibition of respiration and cytochrome oxidation support the suggestion that the susceptibility of cytochrome b to oxidation by molecular oxygen (reflected in its ability to react with CO) is probably irrelevant to the normal physiology of Pseudomonas AM1.

Carbon Monoxide↗
PubMed1976

A purification procedure for the soluble cytochrome oxidase and some other respiratory proteins from Pseudomonas aeruginosa.

The production of the soluble cytochrome oxidase/nitrite reductase in the bacterium Pseudomonas aeruginosa is favoured by anaerobic conditions and the presence of KNO3(20g/l) in the culture medium. Of three methods commonly used for the disruption of bacterial suspensions (ultrasonication, liquid-shear homogenization and glass-bead grinding), sonication proved the most efficient in releasing the Pseudomonas cytochrome oxidase. A polarographic assay of Pseudomonas cytochrome oxidase activity with sodium ascorbate as substrate and NNN'N'-tetramethyl-p-phenylenediamine dihydrochloride as electron mediator is described. A purification procedure was developed which can be used on the small scale (40-litre cultures) or the large scale (400-litre cultures) and provides high yields of three respiratory-chain proteins, Pseudomonas cytochrome oxidase, cytochrome c551 and azurin, in a pure state. A typical preparation of 250g of Ps.aeruginosa cell paste yielded 180mg of Pseudomonas cytochrome oxidase, 81 mg of Pseudomonas cytochrome c551 and 275mg of Pseudomonas azurin.

Azurin↗
PubMed1997

A selective medium for the rapid detection by an impedance technique of Pseudomonas spp. associated with poultry meat.

A new medium for detecting and enumerating Pseudomonas spp. associated with poultry meat spoilage by a rapid impedance technique was developed, after testing potential growth promoters for eight Pseudomonas strains and inhibitors against eight competing strains (Enterobacteriaceae) able to grow on the medium of Mead and Adams (1977). Four basal media (brain heart infusion, brucella broth, Shaedler broth and Whitley impedance broth (WIB)) and a synthetic medium were evaluated. Whitley impedance broth was the best basal medium for detecting variations in impedance in relation to Pseudomonas growth. The efficiency of WIB was improved by adding compounds which enhanced the growth of Pseudomonas on the synthetic medium. Among the incubation temperatures tested, 22 degrees C proved to be the best compromise between growth of Pseudomonas associated with poultry meat spoilage and inhibition of competitors. Among the 15 inhibitory substances evaluated against Pseudomonas competitors, five were chosen for inclusion in the final medium: metronidazole, carbenicilline, cetrimide, cycloheximide and diamide (MCCCD medium). Preliminary results obtained from experiments with beef and pork meat showed that this medium could also be used without diamide and at an incubation temperature of 25 degrees C. The impedance technique using MCCCD medium was then compared with an official method which uses the medium of Mead and Adams (1977) on 106 samples of poultry neck skin. The linear regression coefficient between the two techniques was approximately r = 0.85. Impedance was able to detect 10(3) Pseudomonas g-1 within less than 19 h making it a promising technique for predicting poultry meat spoilage.

Animals↗
PubMed2001

Clinical course of peritonitis due to Pseudomonas species complicating peritoneal dialysis: a review of 104 cases.

BACKGROUND: Peritonitis due to Pseudomonas species is a serious complication in continuous ambulatory peritoneal dialysis (CAPD) patients. The clinical course of peritonitis due to Pseudomonas complicating CAPD remains unclear. METHODS: All of the Pseudomonas species episodes of peritonitis in our dialysis unit were studied from 1995 to 1999. During this period, there were 859 episodes of peritonitis recorded, 113 of which were caused by the Pseudomonas species. Nine episodes were excluded because they were mixed growth. The remaining 104 episodes in 68 patients were reviewed. RESULTS: The underlying renal diagnosis and prevalence of comorbid conditions of the 68 patients were similar to those found in our entire dialysis population. There was a history of antibiotic therapy within 30 days of the onset of peritonitis due to the Pseudomonas species in 69 episodes (66.3%). In 47 episodes (45.2%) there was a concomitant exit site infection. The overall primary response rate was 60.6% and the complete cure rate was 22.1%. The presence of exit site infection was associated with a lower primary response rate (22 in 47 vs. 41 in 57 episodes, P < 0.01) and a lower complete cure rate (5 in 47 vs. 18 in 57 episodes, P < 0.02). The episodes that had received recent antibiotic therapy had a significantly lower complete cure rate than the de novo cases (8 in 69 vs. 15 in 35 episodes, P < 0.001). Episodes receiving third-generation cephalosporin as part of the initial antibiotic regimen had a significantly higher primary response rate than the ones that initially received aminoglycoside (54 in 81 episodes vs. 8 in 22 episodes, P < 0.05), but their complete cure rates were similar. Twenty-four cases failed to respond to antibiotics and the Tenckhoff catheter was removed. The chance of returning to CAPD was higher when the Tenckhoff catheter was removed on day 10 than on day 15 (9 in 14 cases vs. 5 in 10 cases), although the result was not statistically significant. The Tenckhoff catheter was removed and replaced at another site simultaneously in another 14 cases after the effluent cleared up. None of these patients had a relapse of peritonitis within three months. CONCLUSIONS: Recent antibiotic therapy is the major risk factor for peritonitis due to the Pseudomonas species. Exit site infection and recent antibiotic therapy are associated with poor therapeutic response to antibiotics. When the therapeutic response is suboptimal, early Tenckhoff catheter removal may help preserve the peritoneum for further peritoneal dialysis. Elective Tenckhoff catheter exchange after clearing up the peritoneal dialysis effluent may also reduce the likelihood of relapse. It is desirable to use third-generation cephalosporin in the initial antibiotic regimen for peritonitis treatment in localities with a high incidence of peritonitis due to the Pseudomonas species.

Adult↗
PubMed1994

Occurrence and antibiotic-resistance of Pseudomonas species isolated from drinking water in southern Greece.

A total of 194 samples of drinking waters consisting of 88 tap waters and 106 non-carbonated bottled waters were processed for isolation of Pseudomonas species during a 4-month period according to standard methods. Pseudomonas aeruginosa was the predominant isolated Pseudomonas species. Twenty-eight (14.4%) P. aeruginosa were isolated from 194 samples. Eight (9%) were isolated from 88 tap water samples and 20 (18.8%) from 106 bottled water samples. Eight (9%) tap waters yielded non-P. aeruginosa strains while bottled waters yielded 22 (20.7%) non-P. aeruginosa strains (P < 0.05). Antibiotic-resistant strains of Pseudomonas species have been isolated from the drinking waters. All but Pseudomonas stutzeri species had a multiple chloramphenicol-erythromycin resistance phenotype. Streptomycin and tetracycline resistance for P. aeruginosa was invariably accompanied by chloramphenicol, tetracycline, erythromycin and nalidixic acid resistance. The susceptibility of Pseudomonas species to newer antimicrobial agents (beta lactams, aminoglycosides, third generation cephalosporins and quinolones) was also evaluated. Ceftazidime and ciprofloxacin seemed to be the most active molecules. There were no resistant P. aeruginosa and P. stutzeri strains to all newer antibiotics tested while Pseudomonas maltophilia was the most resistant among the tested species (69.2% resistance for the newer antibiotics).

Drug Resistance, Microbial↗
PubMed1984

Identification of the principal T lymphocyte-stimulating antigens of Pseudomonas aeruginosa.

To aid in understanding the role of cellular immunity in limiting Pseudomonas aeruginosa infections, we have identified some of the principal antigens of the organism that are recognized by human T cells. Clones of T cells were selected in such a manner that they would provide information not only about the identity of Pseudomonas antigens, but also the T cell repertoires of immune donors. Most clones were found to be specific for Pseudomonas alkaline protease (AP). Such clones could be physically isolated by selecting with crude Pseudomonas antigens or purified AP. In either case, their fine specificities were the same when tested against a panel of Pseudomonas antigens. The conclusion that AP is the principal immunogen for many donors was confirmed by measuring the absolute frequencies of proliferating T cells committed to AP and all other Pseudomonas antigens. Frequencies of AP-specific clones (1.5-2.7 X 10(-5] were comparable to those from the same donors that were specific for all secreted Pseudomonas antigens (1.3-6.0 X 10(-5]. These results provide a model system for studying human T cell-mediated immunity to bacteria by identifying discrete antigens and measuring the repertoire diversities of cells responding to them.

Adult↗
PubMed2004

Plant perceptions of plant growth-promoting Pseudomonas.

Plant-associated Pseudomonas live as saprophytes and parasites on plant surfaces and inside plant tissues. Many plant-associated Pseudomonas promote plant growth by suppressing pathogenic micro-organisms, synthesizing growth-stimulating plant hormones and promoting increased plant disease resistance. Others inhibit plant growth and cause disease symptoms ranging from rot and necrosis through to developmental dystrophies such as galls. It is not easy to draw a clear distinction between pathogenic and plant growth-promoting Pseudomonas. They colonize the same ecological niches and possess similar mechanisms for plant colonization. Pathogenic, saprophytic and plant growth-promoting strains are often found within the same species, and the incidence and severity of Pseudomonas diseases are affected by environmental factors and host-specific interactions. Plants are faced with the challenge of how to recognize and exclude pathogens that pose a genuine threat, while tolerating more benign organisms. This review examines Pseudomonas from a plant perspective, focusing in particular on the question of how plants perceive and are affected by saprophytic and plant growth-promoting Pseudomonas (PGPP), in contrast to their interactions with plant pathogenic Pseudomonas. A better understanding of the molecular basis of plant-PGPP interactions and of the key differences between pathogens and PGPP will enable researchers to make more informed decisions in designing integrated disease-control strategies and in selecting, modifying and using PGPP for plant growth promotion, bioremediation and biocontrol.

Immunity, Innate↗
PubMed1992

Transfer of several phytopathogenic Pseudomonas species to Acidovorax as Acidovorax avenae subsp. avenae subsp. nov., comb. nov., Acidovorax avenae subsp. citrulli, Acidovorax avenae subsp. cattleyae, and Acidovorax konjaci.

DNA-rRNA hybridizations, DNA-DNA hybridizations, polyacrylamide gel electrophoresis of whole-cell proteins, and a numerical analysis of carbon assimilation tests were carried out to determine the relationships among the phylogenetically misnamed phytopathogenic taxa Pseudomonas avenae, Pseudomonas rubrilineans, "Pseudomonas setariae," Pseudomonas cattleyae, Pseudomonas pseudoalcaligenes subsp. citrulli, and Pseudomonas pseudoalcaligenes subsp. konjaci. These organisms are all members of the family Comamonadaceae, within which they constitute a separate rRNA branch. Only P. pseudoalcaligenes subsp. konjaci is situated on the lower part of this rRNA branch; all of the other taxa cluster very closely around the type strain of P. avenae. When they are compared phenotypically, all of the members of this rRNA branch can be differentiated from each other, and they are, as a group, most closely related to the genus Acidovorax. DNA-DNA hybridization experiments showed that these organisms constitute two genotypic groups. We propose that the generically misnamed phytopathogenic Pseudomonas species should be transferred to the genus Acidovorax as Acidovorax avenae and Acidovorax konjaci. Within Acidovorax avenae we distinguished the following three subspecies: Acidovorax avenae subsp. avenae, Acidovorax avenae subsp. cattleyae, and Acidovorax avenae subsp. citrulli. Emended descriptions of the new taxa are presented.

DNA, Bacterial↗
PubMed1995

Comparative ribosomal protein sequence analyses of a phylogenetically defined genus, Pseudomonas, and its relatives.

I analyzed various families of ribosomal proteins obtained from selected species belonging to the genus Pseudomonas sensu stricto and allied organisms which were previously classified in the genus Pseudomonas. Partial amino acid sequencing of L30 preparations revealed that the strains which I examined could be divided into three clusters. The first cluster, which was assigned to the genus Pseudomonas sensu stricto, included Pseudomonas aeruginosa, Pseudomonas putida, Pseudomonas mendocina, and Pseudomonas fluorescens. The second cluster included Burkholderia pickettii and Burkholderia plantarii. The third cluster, which was a deeply branching cluster in the stem of gram-negative bacteria, included Brevundimonas diminuta and Brevundimonas vesicularis. Despite the different levels of conservation of the N-terminal sequences of ribosomal protein families (the highest level of similarity was 74% for L27 proteins and the lowest level of similarity was 42% for L30 proteins), similar phylogenetic trees were constructed by using data obtained from sequence analyses of various ribosomal protein families, including the S20, S21, L27, L29, L31, L32, and L33 protein families. Thus, I demonstrated the efficacy of ribosomal protein analysis in bacterial taxonomy.

Amino Acid Sequence↗
PubMed2000

Pseudomonas frederiksbergensis sp. nov., isolated from soil at a coal gasification site.

Phenotypic and genotypic characterization indicated that a group of 29 closely related phenanthrene-degrading bacteria from a coal gasification site in Frederiksberg, Copenhagen, Denmark, belonged to the genus Pseudomonas. The strains were isolated at two sampling occasions 2 years apart. The isolates were phenotypically different from any known species of the genus Pseudomonas and were therefore subject to further identification. Colonies were smooth and pale yellowish and did not produce pigments fluorescent in UV light when grown on King's B agar. Cells were rod-shaped, approximately 0.5-0.8 x 1.5-3.0 microm, and grew at 4 and 30 degrees C, but not 37 degrees C. The bacteria were oxidase- and catalase-positive, accumulated poly-beta-hydroxybutyrate and denitrified, but did not utilize D-xylose. The mean G+C content was 59.6 mol%. Phenotypic data and 16S rDNA sequence data information for Pseudomonas amygdali and Pseudomonas corrugata, and 16S rDNA sequence data for Pseudomonas chlororaphis and Pseudomonas syringae showed close relationships to these strains. However, DNA-DNA hybridization data showed that the isolates belong to a new species, for which the name Pseudomonas frederiksbergensis sp. nov. is proposed. The type strain is JAJ28T (DSM 13022T).

Bacterial Typing Techniques↗
PubMed1996

Interaction between fish spoilage bacteria Pseudomonas sp. and Shewanella putrefaciens in fish extracts and on fish tissue.

The interaction between fish spoilage bacteria, Pseudomonas sp. and Shewanella putrefaciens, was investigated using fish extract and fish tissue as model systems. Isolates of Pseudomonas that produced iron chelators, siderophores, inhibited growth of S. putrefaciens in a fish-extract-agar diffusion assay but no, or only weak, antagonistic activity was seen when the medium was supplemented with iron. Sterile-filtered supernatant fluid from a siderophore-producing Pseudomonas grown in fish extract was inhibitory to S. putrefaciens if the number of Psudomonas was above 10(8) cfu ml-1. In contrast, supernatant fluids from siderophore-negative Pseudomonas isolates did not inhibit growth of S. putrefaciens. The inhibitory effect was, except for one strain of Pseudomonas, not seen in supernatant fluids from iron-enriched cultures of Pseudomonas sp. Finally, siderophore-producing Pseudomonas sp. lowered the maximum cell level of S. putrefaciens 1-2 log units from 10(9) to 10(10) cfu g-1 when the strains were grown on fish muscle blocks at 0 degrees C but the growth rate of S. putrefaciens was not affected.

Agar↗
PubMed1993

The ORF1 of the gentamicin-resistance operon (aac) of Pseudomonas aeruginosa encodes adenosine 5'-phosphosulphate kinase.

The gentamicin-resistance operon of Pseudomonas aeruginosa (aac) contains two cistrons for which only the second gene product has an identified function. The 813bp second cistron (ORF2) encodes a protein that confers gentamicin resistance by catalysis of the transfer of an acetyl group from acetyl Coenzyme A to gentamicin. The first open reading frame (ORF1) encodes a 23.9 kDa protein that we have found, by enzyme activity and immunological reactivity, to be adenosine-5'-phosphosulphate (APS) kinase. APS kinase catalyses the transfer of the gamma phosphoryl group of ATP to the 3'-hydroxyl group of APS. The 70% sequence similarity between the Pseudomonas and Escherichia coli APS kinases suggests that the Pseudomonas enzyme may catalyse phosphoryl transfer to the 3'-hydroxyl group of other nucleotides such as dephosphocoenzyme A, as does the purified E. coli APS kinase. In extracts of pseudomonad cells we have also detected a higher molecular mass (70kDa) protein that cross-reacts with an anti-E. coli APS kinase antibody. This cross-reactive protein is also present in Pseudomonas strains lacking the gentamicin-resistance plasmid, and apparently reflects an APS kinase analogous to the nodQ-encoded high-molecular-weight APS kinase present in Rhizobium meliloti. Production of the Pseudomonas aac APS kinase was repressed by cysteine when expressed in E. coli, as is E. coli APS kinase. However, cysteine did not repress production of the Pseudomonas enzyme when the aac ORF1-encoded enzyme was expressed in a Pseudomonas strain, indicating differential regulation of gene expression in the two organisms.

Amino Acid Sequence↗