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At least 19 recordsLinked to original sources
PubMed1976

Fumarate reduction in Proteus mirabilis.

1. Proteus mirabilis formed fumarate reductase under anaerobic growth conditions. The formation of this reductase was repressed under conditions of growth during which electron transport to oxygen or to nitrate is possible. In two of three tested chlorate-resistant mutant strains of the wild type, fumarate reductase appeared to be affected. 2. Cytoplasmic membrane suspensions isolated from anaerobically grown P. mirabilis oxidized formate and NADH with oxygen and with fumarate, too. 3. Spectral investigation of the cytoplasmic membrane preparation revealed the presence of (probably at least two types of) cytochrome b, cytochrome a1 and cytochrome d. Cytochrome b was reduced by NADH as well as by formate to approximately 80%. 4. 2-n-Heptyl-4-hydroxyquinilone-N-oxide and antimycin A inhibited oxidation of both formate and NADH by oxygen and fumarate. Both inhibitors increased the level of the formate/oxygen steady state and the formate/fumarate steady state. 5. The site of inhibition of the respiratory activity by both HQNO and antimycin A was located at the oxidation side of cytochrome b. 6. The effect of ultraviolet-irradiation of cytoplasmic membrane suspensions on oxidation/reduction phenomena suggested that the role of menaquinone is more exclusive in the formate/fumarate pathway than in the electron transport route to oxygen. 7. Finally, the conclusion has been drawn that the preferential route for electron transport from formate and from NADH to fumarate (and to oxygen) includes cytochrome b as a directly involved carrier. A hypothetical scheme for the electron transport in anaerobically grown P. mirabilis is presented.

Anaerobiosis↗
PubMed1979

Regulation of phenylalanine oxidase synthesis in Proteus mirabilis.

Cells of Proteus mirabilis could oxidize L-phenylalanine to phenylpyruvate only when grown in the presence of a number of amino acids, particularly, L-alanine, L-asparagine, L-glutamate, and L-glutamine. Production of phenylalanine oxidase was slowly lost upon growth in a minimal medium containing ammonium ions as a nitrogen source but was reversed by the addition of casein hydrolysate. Oxidase activity as well as a phenylalanine-dichlorophenolindophenol (DCIP) reductase activity increased in P. mirabilis only during cell multiplication. Both rifampin and nalidixic acid caused inhibition of oxidase synthesis. A phenylalanine-active transport was found to be operative when bacteria were grown in the absence of added amino acids. After anaerobic growth, cells of P. mirabilis had lost their ability to carry the phenylalanine oxidase reaction when assayed in the presence of air, and nitrate could not be used as an electron acceptor for the oxidation of phenylalanine. However, some phenylalanine-dichlorophenolindophenol reductase activity was still present in anaerobic bacteria at the early stage of cell multiplication.

Amino Acid Oxidoreductases↗
PubMed1978

Cerulenin-induced changes in the lipopolysaccharide content and phospholipid composition of Proteus mirabilis.

Inhibition of Proteus mirabilis growth by cerulenin, a specific inhibitor of fatty acid biosynthesis, was reversed by exogenously supplied fatty acid mixtures containing oleic acid and palmitic or pentadecanoic acids. The growth rate of the cells treated with cerulenin in the presence of the fatty acid mixtures was slower, however, than that of untreated cells, and their lipopolysaccharide content was decreased by 30-50%, resulting in an increased sensitivity of the organisms to rifamycin and vancomycin. Polyacrylamide gel electrophoresis of the lipopolysaccharide fraction from cerulenin-treated cells revealed that of the two P. mirabilis lipopolysaccharide types, the relative amount of the higher molecular weight lipopolysaccharide was reduced from 50% to 30% of the total lipopolysaccharide. Fatty acid analysis of the phospholipid and lipopolysaccharide fractions from cells grown with cerulenin, pentadecanoate, and oleate revealed that over 60% of the native even-numbered fatty acids of the phospholipid fraction was substituted by the odd-numbered fatty acid, while no incorporation of either the pentadecanoate or oleate could be demonstrated in the lipid A moiety of the lipopolysaccharide. The only change in the lipid A observed was an increase in the content of 3-hydroxymyristic acid accompanied by a decrease in the nonhydroxylated fatty acids, supporting the highly conserved nature of this molecule.

Antifungal Agents↗
PubMed1979

Mössbauer spectroscopic studies of iron in Proteus mirabilis.

Mössbauer measurements of Proteus mirabilis cells grown in 57Fe-enriched media show that considerable quantities of iron are incorporated, particularly in the stationary phase of growth. A major part of the iron is in a form which shows magnetically split spectra at low temperatures. Fractionation of cells reveals that iron is present in both the soluble and particulate fractions, with the larger proportion being found in the soluble fraction. The iron in the particulate fraction is predominantly found in the outer membrane.

Iron↗
PubMed1978

Lipoprotein from Proteus mirabilis.

The biosynthesis of a Proteus mirabilis outer membrane protein of molecular weight of approximately 7,000 was found to be relatively resistant to puromycin and rifampin, as is the case for the Escherichia coli liporotein. Furthermore, the existence of the lipoprotein in P. mirabilis was indicated by a comparison of the amino acid compositions of the purified free and bound forms of this protein with those of the E. coli free and bound lipoproteins.

Amino Acids↗
PubMed1979

Covalent linkage of lipoprotein to peptidoglycan is not essential for outer membrane stability in Proteus mirabilis.

Isolated rigis layers from Proteus mirabilis harvested at different growth phases were degraded by endo-N-acetylmuramidase from Chalaropsis B, and the degradation products were investigated. The results show the complete absence of covalently linked lipoprotein in exponential-phase cultures. Stationary cells, however, possess covalently linked lipoprotein in amounts similar to those found in Escherichia coli or Salmonella typhimurium during all growth phases. The overall peptidoglycan structure did not change during transition from logarithmic to stationary growth. Implications of these findings for the organization of the outer membrane are discussed.

Bacterial Proteins↗
PubMed1976

Studies of introital colonization in women with recurrent urinary infections. V. The inhibitory activity of normal vaginal fluid on Proteus mirabilis and Pseudomonas aeruginosa.

Normal vaginal fluid from premenopausal volunteers was inoculated with 10 strains of Proteus mirabilis and 14 strains of Pseudomonas aeruginosa at pH's of 4.3, 4.6 and 4.9. All bacteria were killed at pH 4.3. Nine of 10 strains of Proteus mirabilis and 12 of 14 Pseudomonas aeruginosa were killed at pH 4.6. Only 4 of 14 strains of Pseudomonas aeruginosa were killed at pH 4.9, while 8 of 10 strains of Proteus mirabilis were killed at the same pH. We conclude that in comparison to the common 0 group strains of Escherichia coli, vaginal fluid is more bactericidal to Proteus mirabilis and Pseudomonas aeruginosa and that these observations may help explain the relative infrequency of bacteriuria owing to the organisms.

Escherichia coli↗
PubMed1976

The linkage of lysine in the O-specific chains of Proteus mirabilis 1959.

Lipopolysaccharides of qualitatively identical but quantitatively different sugar composition were extracted from Proteus mirabilis strain 1959. The lipopolysaccharide with the higher percentage of typical O-specific constituents was subjected to partial acid hydrolysis. An oligosaccharide B22 was separated by paper chromatography and electrophoresis. It was found to be composed of equimolar amounts of D-galacturonic acid, D-galactosamine and L-lysine. Dinitrophenylation of the oligosaccharide as well as of the genuine lipopolysaccharide afforded xi-dinitrophenyl-L-lysine after acid hydrolysis, showing that lysine was linked to the disaccharide via its alpha-amino group. Further studies including the Morgan-Elson and Elson-Morgan reactions, NaBH4-reduction, hydrazinolysis and periodate oxidation revealed the structure of oligosaccharide B22 as D-galacturonyl-(1 leads to 4)-D-galactosamine with lysine attached to the carboxylic group of galacturonic acid via its alpha-amino group. Judged from its high inhibition capacity this oligosaccharide has to be considered as an essential part of the serological determinant of Proteus mirabilis 1959. The frequent occurrence of lysine and galacturonic acid in Proteus mirabilis O-serogroups and their possible significance for the respective serological specificities are discussed.

ABO Blood-Group System↗
PubMed1976

Evidence against the involvement of chemotaxis in swarming of Proteus mirabilis.

Nonswarming and nonchemotactic mutants of Proteus mirabilis were isolated after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine or ultraviolet light. These mutants were used in experiments to determine if chemotaxis is involved in the swarming of P. mirabilis. Nonchemotactic mutants failed to form chemotactic bands in a semisolid casein hydrolysate medium, yet they swarmed on the same medium containing 1.5% agar. Nonswarming mutants were attracted towards individual amino acids and components of tryptose. In cross-feeding experiments, no evidence was obtained to indicate the production of a diffusable chemical repellent. In studies with the wild-type P. mirabilis, no clear-cut negative chemotaxis was seen even though three different assays were used and numerous chemicals were tested. Additional evidence against the involvement of chemotaxis in swarming comes from finding that dialysis does not interfere with swarming; swarm cells will swarm immediately when transferred to fresh media, and swarm cells will swarm on an agar-water medium supplemented with a surfactant. These data indicate that chemotaxis is not involved in the swarming of P. mirabilis.

Amino Acids↗
PubMed1979

Outer membrane proteins of smooth and rough strains of Proteus mirabilis.

The outer membranes of the smooth Proteus mirabilis S1959 strain and its rough R13, R110, R51 and R45 mutants were isolated by sonication of the cells and sucrose density gradient centrifugation. The outer membrane of the rough strains had a lower density than that of their parent smooth strain, but the protein-to-phospholipid ratios were the same. The electrophoretic patterns of outer membrane polypeptides of the S and R strains in sodium dodecylsulfate/polyacrylamide gels were identical, with two major polypeptide bands, C1 and C2 (Mr 39,000 and 38,000) predominating. The C1 polypeptide band was a heat-modifiable polypeptide, which migrated as a band at Mr 33,000 when membranes were solubilized at 37 degrees C or 50 degrees C, and at Mr 39,000 when solubilization was at 100 degrees C. Susceptibility of outer membrane polypeptides to proteolytic digestion was found to be higher in isolated outer membrane preparations of the rough strains than in the smooth strain, suggesting that the availability of the polypeptide chains to proteolytic activity depends on the length of the polysaccharide chains of the outer membrane lipopolysaccharide.

Cell Membrane↗
PubMed1977

Ribitol-containing lipopolysaccharides from Proteus mirabilis and their serological relationship.

Ribitol phosphate was recently identified as a constituent of lipopolysaccharides obtained from 'proteus mirabilis strain D52 giving 1:4-anhydroribitol during acid hydrolysis (Gmeiner, 1975). Two other Proteus mirabilis strains belonging to serogroups O16 and O33 were shown previously to contain an unknown compoound X as lipopolysaccharide constituent (Kotelko et al., 1975). In this report the identification of compound X as 1:4-anhydroribotol by gas-liquid chromatography, mass spectrometry and mass fragmentography is described. Serological investigations using passive hemagglutination, hemagglutination inhbition and semi-quantitative precipitin reactions indicate strongly that ribitol plays a role in the serological specificity of the respective lipopolysaccharides.

Hemagglutination Inhibition Tests↗
PubMed1977

[Transmission of the R-plasmids and expression of their genes in Proteus mirabilis].

Resistance markers to individual antibiotics are transmitted in E. coli with the same frequency in the shape of a uniform linkage group, and in Proteus mirabilis--with a different one. Possibly in Proteus mirabilis plasmide R6 dissociated, this being expressed in a different incidence of transconjugates, characterized by a different set of antibiotic resistance genes. Tetracyclin resistance gene can be transmitted in P. mirabilis without being bound with other resistance determinants and with the functioning Tra-operon. The expression of individual antibiotic resistance genes of plasmide R6 in P. mirabilis differed, i.e. tetracycline resistance was inducible, and to kanamycin and chloramphenicol--constitutional. The level of expression of the gene controlling the tetracycline resistance was in noninduced condition in P. mirabilis, lower than in E. coli, P. mirabilis containing no R-factor possessed an inducible resistance mechanism to tetracycline, as in case of P. mirabilis strains containing R-factors.

Anti-Bacterial Agents↗
PubMed1979

[Regulation of catalase synthesis in Proteus mirabilis].

During the log-phase growth of Proteus mirabilis the specific activity of catalase decreases, while at the beginning of or during the stationary phase an increase takes place which is abolished by inhibitors of nucleic acid or protein synthesis. Glucose in the culture medium has no appreciable effect on the level of enzyme synthesis nor does the passage of bacteria to anaerobiosis bring any noticeable change. Successive additions of hydrogen peroxide up to weak final concentrations (0.2--0.5 mM) stimulate catalase synthesis. Determination of the enzyme in vivo reveals but a weak proportion of the total catalase which can only be titrated after the breakdown of cells. The titrable enzyme in vivo represents, as an order of magnitude, the activity found associated with the cell wall, in an easily released form after the mechanical separation of the inner and outer membranes. Thus, bacteria can act upon exogenous peroxide only through a peripheral catalase while they possess in a masked form an important reserve of cytoplasmic enzyme.

Anaerobiosis↗
PubMed1978

Structure, function, and regulation of Escherichia coli rRNA in Proteus mirabilis.

Escherichia coli rRNA genes have been introduced into Proteus mirabilis on an F-prime factor (F'14). A portion of the ribosomes in the resulting merodiploid consist of E. coli rRNA and P. mirabilis ribosomal proteins. These ribosomes are structurally similar to normal P. mirabilis or E. coli ribosomes and exhibit many or all of the functional properties of normal ribosomes. The accumulation of E. coli rRNA in the merodiploid is regulated in a way similar to the the regulation of P. mirabilis rRNA.

Bacterial Proteins↗
PubMed1976

Transcription of Escherichia coli ribosomal DNA in Proteus mirabilis.

Transcription of Escherichia coli ribosomal DNA introduced into Proteus mirabilis on F14 is described. We have developed an assay for E. coli coded ribosomal RNA involving fingerprinting of ribonuclease T1 digests of RNA isolated from ribosomal subunits. Sequence differences in the ribosomal RNA of the two species have allowed us to detect E. coli coded 16S, 23S, and 5S ribosomal RNA in ribosomal subunits of the E. coli-P. mirabilis hybrid. The proportion of E. coli coded rRNA in the hybrid is found at a level which is compatible with the number of E. coli (and P. mirabilis) ribosomal DNA sequences. The resulting ribosomal RNA appears in ribosomes in a form which indicates extensive compatibility of E. coli coded ribosomal RNA with P. mirabilis ribosomal proteins and maturational factors.

Base Sequence↗
PubMed1976

Growth inhibition of Proteus mirabilis by cyclic adenosine 3'-5'-monophosphate.

Growth of Proteus mirabilis on a synthetic agar medium containing either glycerol, galactose, or trehalose as the sole source is inhibited by 5 mM cyclic adenosine 3',5'-monophosphate (cAMP). Inhibition on an agar medium is evident as loss of viability, but in broth cAMP only slightly inhibits growth rate. Inhibition is associated with the accumulation of methylglyoxal in the medium. A nonswarming mutant of P. mirabilis is not inhibited by cAMP on either of the three carbon sources, but it is sensitive to exogenous methylglyoxal.

Cyclic AMP↗