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PubMed2003

Crystal structure of Proteus vulgaris chondroitin sulfate ABC lyase I at 1.9A resolution.

Chondroitin Sulfate ABC lyase I from Proteus vulgaris is an endolytic, broad-specificity glycosaminoglycan lyase, which degrades chondroitin, chondroitin-4-sulfate, dermatan sulfate, chondroitin-6-sulfate, and hyaluronan by beta-elimination of 1,4-hexosaminidic bond to unsaturated disaccharides and tetrasaccharides. Its structure revealed three domains. The N-terminal domain has a fold similar to that of carbohydrate-binding domains of xylanases and some lectins, the middle and C-terminal domains are similar to the structures of the two-domain chondroitin lyase AC and bacterial hyaluronidases. Although the middle domain shows a very low level of sequence identity with the catalytic domains of chondroitinase AC and hyaluronidase, the residues implicated in catalysis of the latter enzymes are present in chondroitinase ABC I. The substrate-binding site in chondroitinase ABC I is in a wide-open cleft, consistent with the endolytic action pattern of this enzyme. The tryptophan residues crucial for substrate binding in chondroitinase AC and hyaluronidases are lacking in chondroitinase ABC I. The structure of chondroitinase ABC I provides a framework for probing specific functions of active-site residues for understanding the remarkably broad specificity of this enzyme and perhaps engineering a desired specificity. The electron density map showed clearly that the deposited DNA sequence for residues 495-530 of chondroitin ABC lyase I, the segment containing two putative active-site residues, contains a frame-shift error resulting in an incorrectly translated amino acid sequence.

Amino Acid Sequence↗

PubMed1993

Proteus syndrome: diagnosis and surgical management.

The congenital hamartomatous syndrome known as the "Proteus syndrome" (PS) manifests itself with regional giantism, lymphangiomatous hamartomas, and other variable features. Review of the medical literature shows approximately 50 cases reported to date. Since this syndrome has only recently been defined, the management of these patients has been speculative and often children are not treated. This report summarizes the characteristics of the PS and presents eight additional cases. All of the eight children had regional giantism with macrodactyly and skeletal hypertrophy. Asymmetrical leg length was pronounced in five children. All children had large lymphangiomas, the majority of which involved the trunk. Three of the children have been followed through adolescence, two into late childhood, and three into early childhood. In contrast to previous reports, we believe that early surgical reconstruction is necessary to reduce deformities due to the giantism and the large hamartomas. During extensive excisions, residual abnormal tissue is often needed in the reconstruction and it is not unusual for postoperative leakage of lymph to be prolonged. All of the children in this series have benefited both physically and emotionally from extensive surgical reconstruction.

Female↗

PubMed1991

Proteus mirabilis biofilm protection against struvite crystal dissolution and its implications in struvite urolithiasis.

Proteus mirabilis biofilm formation, struvite (MgNH4PO4.6H2O) crystal formation and dissolution in an artificial urine mixture were monitored using computer-enhanced microscopy (CEM) and a 1 x 3 mm. glass flow cell. Image analysis showed that P. mirabilis biofilm formation did not occur to any extent at macroenvironment flow rates greater than two mL/h (equivalent to a microenvironment flow rate of less than 5 microns./sec). Essentially, cells attached to glass surfaces, grew slowly and divided. Daughter cells were generally released directly into the medium where they could then presumably colonize other regions. Microcolonies formed by the adhesion of aggregates of cells from the medium, and over time grew into biofilms. Struvite crystallization due to urease activity and pH elevation above neutrality, was preceded by the deposition of organic matter on the glass surface, followed by the appearance of a number of tiny (one to two microns.) crystals. Crystals forming within a biofilm at low dilution rates took on a characteristic twinned or "X-shaped" appearance (crystal habit) indicative of a rapid growth rate. Those forming outside the biofilm took on a more tabular appearance reflecting their slower growth. When the macroenvironment flow rate of artificial urine (initial pH 5.8) in the glass flow cell was increased from two mL/h to four mL/h, struvite crystals not associated with biofilms dissolved within five to 10 min. Crystals entrapped within the P. mirabilis biofilm withstood flow rates up to 200 mL/h presumably due to the maintenance of an alkaline Mg-saturated microenvironment within the biofilm. These observations may suggest a mechanism by which struvite calculi can grow in spite of neutral or acidic urine pH and resist mild acidification therapy.

Bacterial Adhesion↗

PubMed1990

Influence of chondroitin sulfate, heparin sulfate, and citrate on Proteus mirabilis-induced struvite crystallization in vitro.

Struvite crystals were produced by Proteus mirabilis growth in artificial urine, in the presence of a number of naturally occurring crystallization inhibitors. The use of phase contrast light microscopy enabled the effects of added chondroitin sulfate A, chondroitin sulfate C, heparin sulfate, or sodium citrate, on struvite crystal growth rates to be rapidly monitored as changes in crystal habit. Struvite crystals formed as a consequence of the urease activity of P. mirabilis under all chemical conditions. In the absence of inhibitor, early crystal development was marked by large quantities of amorphous precipitate, followed immediately by the appearance of rapidly growing X-shaped or planar crystals. Addition of the glycosaminoglycans, chondroitin sulfate A, chondroitin sulfate C, or heparin sulfate to the artificial urine mixture had no effect on the rate of crystal growth or appearance. When sodium citrate was present in elevated concentrations, crystal appearance was generally slowed, and the crystals assumed an octahedral, slow growing appearance. None of the added compounds had any influence on bacterial viability, pH, or urease activity. It is therefore likely that the inhibitory activity displayed by sodium citrate might be related to its ability to complex magnesium or to interfere with the crystal structure during struvite formation. From these experiments it would appear that citrate may be a factor in the natural resistance of whole urine to struvite crystallization.

Chondroitin Sulfates↗

PubMed1984

Hyperammonemia in a boy with obstructive ureterocele and proteus infection.

We report on a boy with ureteroceles that obstructed the bladder outlet and ureters, who presented with sepsis and hyperammonemia despite normal liver function. The hyperammonemia was most likely caused by excessive absorption of ammonia produced by Proteus mirabilis in the obstructed urinary tract.

Ammonia↗

PubMed1978

Studies of introital colonization in women with recurrent urinary infections. X. Adhesive properties of Escherichia coli and Proteus mirabilis: lack of correlation with urinary pathogenicity.

The ability of a bacterial strain to adhere to the vaginal mucosa and the mucosa of the urinary conduits seems to be important in the pathogenesis of urinary infection. Bacterial adherence to vaginal epithelial cells was measured in vitro for 37 strains of Escherichia coli and 18 strains of Proteus mirabilis isolated from the anus, bladder and renal pelvis. No correlation could be demonstrated between the adhesive properties of a bacterial strain and its clinical pathogenicity, suggesting that host factors determining bacterial adherence are more important than bacterial adhesive factors in determining susceptibility to urinary infections.

Adhesiveness↗

PubMed2001

The generation of superoxide anion in blood platelets in response to different forms of Proteus mirabilis lipopolysaccharide: effects of staurosporin, wortmannin, and indomethacin.

Lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria may activate blood platelets. The aim of our study was to evaluate the effects of different forms of Proteus mirabilis LPS and isolated lipid A and polysaccharide part on the production of superoxide radicals in blood platelets and to estimate the role staurosporin, wortmannin and indomethacin on this process. We compared the generation of superoxide radicals in platelets treated with LPS after preincubation with inhibitors of the signal transduction pathways, namely staurosporin (inhibitor of protein kinase C), wortmannin (inhibitor of phosphoinositide 3-kinase), and indomethacin (inhibitor of cycloxygenase). Our results demonstrate that all LPS molecules and their fragments caused a stimulation of O2- generation in platelets (P<.5). LPSS1959 had the strongest stimulatory effect. Straurosporin and wortmannin, but not indomethacin inhibited O2- production in LPS-stimulated platelets. Staurosporin (8 nM) and wortmannin (50 nM) caused about 50% inhibition of thrombin-induced O2- generation in platelets, while indomethacin (10 microM) had only a slight inhibitory effect on this process. Our results provide support that in LPS- and thrombin-activated platelets, at least part of O2- generation in platelets, while indomethacin (10 microM) had only a slight inhibitory effect on this process. Our results provide support that in LPS- and thrombin-activated platelets, at least part of O2- is generated due to the activation of the enzymes (protein kinase C and phosphoinositide 3-kinase) involved in signal transduction pathway. Cycloxygenase seems to be not involved in this process.

Androstadienes↗

PubMed1998

A new tetracycline resistance determinant cloned from Proteus mirabilis.

The chromosomal inducible Tcr determinant from Proteus mirabilis was cloned and the nucleotide sequence of both the structural and repressor genes determined. The deduced amino acid sequence of the structural protein shows the highest similarity to TetA(H) from Pasteurella multocida (78.4%), followed by TetA(B) from Tn10 (50.9%). Based on this analysis, we suggest that this new determinant can be assigned to a new class, TetJ.

Amino Acid Sequence↗

PubMed1985

Production of brownish pigment by bacteria of the Morganella-Proteus-Providencia group.

All bacteria of the Morganella-Proteus-Providencia group tested produced a brownish pigment on agar containing L-forms of aromatic amino acids, i.e. histidine, phenylalanine, tryptophan, and tyrosine in the presence of iron ions under aerobic conditions. No pigment was observed without iron or when using D-forms of the amino acids. It is a melanin-like pigment with variable molecular weight under about 12000 D and an absorbance maximum between 330 and 410 nm depending on the concentration and the amino acid metabolized. Moreover, there is evidence that aldehydes are intermediates. In addition, the bacteria develop a characteristic almond-like smell on phenylalanine agar.

Amino Acids↗

PubMed1986

Properties of an inducible beta-lactamase from Proteus vulgaris.

The inducible beta-lactamase of the clinical Proteus vulgaris isolate 4917/81 was highly purified by column chromatography and by FPLC (cation ion exchange column). Molecular weight of the enzyme amounted 33,000 daltons, as revealed by SDS-electrophoresis. The enzyme was not inhibited by p-chloromercuribenzoate, but by low concentrations of oxacillin and clavulanic acid. The enzyme inactivated not only penicillin derivatives (including ureidopenicillins), but also first-generation cephalosporins and above all oxime-cephalosporins such as cefuroxime, cefotaxime and related derivatives. Turnover rates of these agents were mainly influenced by the nature of substitution in 3' position of the cephalosporin nucleus. Breakdown was not detectable in compounds which were substituted in 6 alpha or 7 alpha position, respectively. The enzyme proved to be very sensitive to the nature of 6 alpha or 7 alpha substituent, as revealed by the study of enzyme kinetics; no turnover could be detected for the penem Sch29 482, imipenem, latamoxef, and aztreonam.

Anti-Bacterial Agents↗

PubMed1998

Encrustation of indwelling urethral catheters by Proteus mirabilis biofilms growing in human urine.

The encrustation and blockage of four types of urinary catheters was studied in a simple laboratory model of the catheterized bladder. Pooled human urine was supplied to the bladder chamber at 0.5 mL/min. The bladder urine was inoculated with a clinical strain of Proteus mirabilis that had been isolated from an encrusted catheter. The models were operated until the catheters blocked and atomic absorption spectrometry was used to assess the amounts of calcium and magnesium deposited on the catheters. Scanning electron microscopy was also used to locate and assess the degree of encrustation. All catheters blocked rapidly, the mean times to blockage ranging from 17.7 h (silver-coated latex), 34 h (hydrogel-coated latex), 38 h (silicone-coated latex) to 47 h (all silicone). The internal diameters of the latex catheters were only 1.5 mm compared to the 2.5 mm of the all-silicone catheters. The calcium and magnesium salts were deposited on the lumenal surfaces along the full length of catheters but occurred most extensively just below the eye-holes. There is clearly a need to develop catheter surfaces which resist encrustation by crystalline biofilms of P. mirabilis.

Bacteriuria↗

PubMed1975

Comparative study of the 16S RNA's of Escherichia coli and Proteus vulgaris.

We have studied the primary structure of 16S ribosomal RNA from Proteus vulgaris. The oligonucleotides containing methylated bases appeared to be the same as those of Escherichia coli, with one exception. We have also studied the base composition of the oligonucleotides obtained after T1 ribonuclease digestion of 16S RNA. On the basis both of their position on the fingerprint and of their pancreatic ribonuclease analyses, approximately 25 appeared to differ from those found in the E. coli T1 fingerprints. From the isolation of large fragments arising from the action of endogeneous endonucleases, we have concluded that the RNA sequences of both species are very similar. We have shown that the 5' and 3' extremities of 16S RNA are mostly conserved. It appears that the regions which are known to interact with ribosomal proteins in E. coli (particularly S8 and S15) are also less modified. It is noteworthy that the sequence modifications which have been observed are clustered and often correspond to regions of heterogeneity in E. coli 16S RNA.

Alkaline Phosphatase↗

PubMed1975

Sequence studies on the 5S RNA of Proteus vulgaris: comparison with 5S RNA of Escherichia coli.

We have studied the sequence of 5S ribosomal RNA of Proteus vulgaris. Although several doubts remain, it seems that no more than 8 per cent of the nucleotides differ from those of Escherichia coli 5S RNA. Of the ten bases differing from Escherichia coli 5S RNA sequence, three changes take place in one of the six positions which are known as intercistronic mutation points in Escherichia coli 5S RNA. We can conclude that they are "hot spots" of mutation.

Base Sequence↗

PubMed1976

[Inducible cephalosporinases from Proteus morganii].

It has been shown that two Proteus morganii strains produce an inducible cephalosporinase. No significative difference was shown between them: they present the same isoelectric poit: 8,3 and very similar kinetic constants. The parameter tau, proportional to the half life of antibiotic at low concentration, in presence of beta lactamase, shows that cefamandole is the most stable cephalosporin studied.

Amidohydrolases↗

PubMed1982

Generation of hydrogen peroxide during the oxidation of L-phenylalanine by Proteus mirabilis isolated membranes.

In the process of L-phenylalanine oxidation by Proteus mirabilis cytoplasmic membrane, hydrogen peroxide was produced at a rate corresponding to 1-3 per cent of the total electron flow (30-110 nmoles min-1mg-1). Peroxide was estimated using a fluorimetric assay with horseradish peroxidase, or by anodic oxidation on a platinum electrode. When using the former method, superoxide dismutase decreased the apparent yield of peroxide, a fact suggesting that H2O2 was in part the dismutation product of superoxide radicals. However the superoxide dismutase effect could be an artefact due to the generation of some superoxide during the peroxidatic reaction in the assay. Adrenaline was the reagent used for the detection of superoxide. There was no significant emergence of superoxide as the result of phenylalanine oxidation by the membrane (specific activity lower than 1-2 nmoles min-1mg-1). Thus it seemed that superoxide was not an intermediate for the bulk of H2O2 formed in this system. According to the results, peroxide was probably formed at a stage of electron transport earlier than the cytochrome level. The membrane phenylalanine dehydrogenase could be a site where peroxide was evolved in these experiments.

Amino Acids↗

PubMed1997

Structural analysis of compound I in hemoproteins: study on Proteus mirabilis catalase.

Ferryl catalysis has attracted considerable interest, because a diverse variety of enzymes use ferryl intermediates to perform difficult chemistry. The structure of the reactional intermediate compound I of Proteus mirabilis catalase (PMC) has been solved using time-resolved X-ray diffraction techniques and single crystal microspectrophotometry. Formation of compound I is characterized by significant changes in the absorbance spectrum, and the creation of an oxoferryl group on the distal side of the heme. This group is clearly visible in the X-ray electron density maps. An unidentified electron density, likely to be an anion because of the nature of its environment, appears during the reaction, in a site distant from the heme. The structure of compound I in PMC is compared with that of compound I in cytochrome c peroxidase (CCP).

Catalase↗

PubMed2002

[Identification of plasmid-encoded cephalosporinase ACC-1 among various enterobacteria (Klebsiella pneumoniae, Proteus mirabilis, Salmonella) isolated from a Tunisian hospital (Sfax 997-2000)].

Because a multiresistant K. pneumoniae outbreak detected in an intensive care unit of a parisian hospital, combined to the production of the plasmid-encoded cephalosporinase ACC-1, a probable importation via a patient was suggested from another country (Tunisia). The investigation was conducted to examine 35 clinical strains of enterobacteria resistant to ceftazidime without synergy towards Augmentin. Other test of synergy with two inhibitors, BRL 42715, Ro 48-5545 was performed by diffusion method and deposit of 10 micrograms of inhibitor on disks containing ceftazidime, cefoxitin and cefotetan. Synergies were obtained suggesting a probable production of ACC-1 type among six isolates of K. pneumoniae (two), Proteus mirabilis (one) and Salmonella (three) issued from different units. The isoelectric focusing on gel revealed at least one band of beta-lactamase activity at 7.8 but also demonstrated the simultaneous production of several probable beta-lactamases including TEM-type, SHV-2 and ACC-1 among S. enterica ser. Livingstone. The PCR of the gene blaacc-1 was positive. The sequencing (1160 pb) of two products showed high identity (99-100%) with the gene blaacc-1 deposited in 1999. Finally the ACC-1 type reported in Tunisia was probably imported in France via a patient. Because a simultaneous synthesis of ESBL and ACC-1 type, its presence may be invisible and need more investigation.

Cephalosporinase↗

PubMed2003

The XerC recombinase of Proteus mirabilis: characterization and interaction with other tyrosine recombinases.

XerC and XerD are two site-specific recombinases, which act on different sites to maintain replicons in a monomeric state. This system, which was first discovered and studied in Escherichia coli, is present in several species including Proteus mirabilis, where the XerD recombinase was previously characterized by our laboratory. In this paper, we report the presence of the xerC gene in P. mirabilis. Using in vitro reactions, we show that the two P. mirabilis recombinases display binding and cleavage activity on the E. coli dif site and the ColE1 cer site, together or in collaboration with E. coli recombinases. In vivo, P. mirabilis XerC and XerD are able to resolve and monomerize a plasmid containing two cer sites, increasing its stability. However, P. mirabilis XerC, in combination with E. coli XerD, is unable to perform these functions.

Amino Acid Sequence↗