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PubMed1971

The biosynthesis of valine from isobutyrate by peptostreptococcus elsdenii and Bacteroides ruminicola.

1. Growing cultures of Peptostreptococcus elsdenii and Bacteroides ruminicola incorporate (14)C from [1-(14)C]isobutyrate into the valine of cell protein. With P. elsdenii some of the (14)C is also incorporated into leucine. 2. Crude cell-free extracts of both organisms in the presence of glutamine, carbon dioxide and suitable sources of energy and electrons incorporate (14)C from [1-(14)C]isobutyrate into valine but not into leucine. 3. With extracts of P. elsdenii treated with DEAE-cellulose the reaction is dependent on ATP, CoA, thiamin pyrophosphate, molecular hydrogen and a low-potential electron carrier (ferredoxin, flavodoxin or benzyl viologen). 4. The same extracts incorporate (14)C from NaH(14)CO(3) into valine in the presence of isobutyrate plus ATP, CoA, glutamine and ferredoxin; isobutyryl-CoA or isobutyryl phosphate plus CoA will replace the isobutyrate plus CoA and ATP. With acetyl phosphate in place of isobutyryl phosphate, (14)C is incorporated into alanine. With isovalerate or 2-methylbutyrate in place of isobutyrate, (14)C is incorporated into leucine and isoleucine respectively. 5. When carrier 2-oxoisovalerate is added to the carboxylating system (14)C from [1-(14)C]isobutyrate passes into the oxo acid fraction. 6. It is concluded that these two organisms form valine from isobutyrate by the sequence isobutyrate-->isobutyryl-CoA-->2-oxoisovalerate-->valine and that the reductive carboxylation of isobutyrate is catalysed by a system similar to the pyruvate synthetase of clostridia and photosynthetic bacteria.

Adenosine Triphosphate↗

PubMed1971

The purification and properties of butyryl-coenzyme A dehydrogenase from Peptostreptococcus elsdenii.

Butyryl-CoA dehydrogenase prepared by a simple procedure from Peptostreptococcus elsdenii has a molecular weight of approx. 150000. The enzyme has FAD as its prosthetic group. The amino acid analysis is reported. This enzyme, like most of the corresponding mammalian ones, is green. The absorption band at 710nm can be abolished irreversibly by dithionite reduction and air reoxidation; it can be abolished reversibly by phenylmercuric acetate or potassium bromide. The enzyme as isolated appears to be a mixture of a green and a yellow form, both of which are active. This view is supported by the variable ;greenness' of different preparations and the biphasic curve obtained in anaerobic spectrophotometric titrations with dithionite. It can be calculated from the titration results that fully green enzyme would have a peak-to-peak absorption ratio (E(710)/E(430)) as great as 0.54. The green form is much less rapidly reduced by dithionite than the yellow form, but is nevertheless much more readily reduced by dithionite than the enzyme from pig liver. It is also more readily reoxidized by air and shows less tendency to form a semiquinone. Treatment with sodium borohydride produces an unusual reduced species that is probably the 3,4-dihydroflavin.

Amino Acids↗

PubMed2003

Immunoglobulin-binding domains: Protein L from Peptostreptococcus magnus.

Protein L is a multidomain cell-wall protein isolated from Peptostreptococcus magnus. It belongs to a group of proteins that contain repeated domains that are able to bind to Igs without stimulating an immune response, the most characterized of this group being Protein A ( Staphylococcus aureus ) and Protein G ( Streptococcus ). Both of these proteins bind predominantly to the interface of C(H)2-C(H)3 heavy chains, while Protein L binds exclusively to the V(L) domain of the kappa -chain. The function of these proteins in vivo is not clear but it is thought that they enable the bacteria to evade the host's immune system. Two binding sites for kappa -chain on a single Ig-binding domain from Protein L have recently been reported and we give evidence that one site has a 25-55-fold higher affinity for kappa -chain than the second site.

Amino Acid Sequence↗

PubMed1973

Dependence of the proton magnetic resonance spectra on the oxidation state of flavodoxin from Clostridium MP and from Peptostreptococcus elsdenii.

The broadening of protein nuclear magnetic resonances in the spectra of the semiquinone forms of flavodoxins derived from Clostridium MP and Peptostreptococcus elsdenii relative to the resonances in the oxidized and reduced forms is highly selective. Spectra from both species of flavodoxin indicate that conformational differences between the oxidized and fully reduced states are minor and, consequently, the broadening in the semiquinone form is ascribed to the paramagnetic effect of the flavin free radical. The chemical shifts of the paramagnetically broadened lines are used in conjunction with x-ray crystallographic models to assign peaks to amino-acid residues in the proximity of the flavin mononucleotide. Species-dependent differences in the spectra can generally be attributed to differences in amino-acid composition and sequence. The spectra from both species of flavodoxin indicate that there is slow exchange between oxidized and semiquinone forms or reduced and semiquinone forms of the flavodoxins with a limit of k(ex) < 50 sec(-1) for the exchange rate.

Amino Acid Sequence↗

PubMed1991

Anaerobic pathogenesis: collagenase production by Peptostreptococcus magnus and its relationship to site of infection.

Fifty isolates of Peptostreptococcus magnus from intraabdominal sepsis, nonpuerperal breast abscess, and diabetic foot infections were examined for collagenase activity using bovine type I collagen. Collagenase production was detected in a higher percentage of strains from nonpuerperal breast and diabetic foot specimens (P less than .001). This enzyme may be responsible for P. magnus playing a more central role in the pathogenesis of nonpuerperal breast abscess and diabetic foot disease than in intraabdominal sepsis.

Abscess↗

PubMed1997

Inhibitory effects of metronidazole on anaerobic metabolism of phenylalanine and leucine by Peptostreptococcus anaerobius.

The metabolism of phenylalanine and leucine by Peptostreptococcus anaerobius and the effects of metronidazole on this metabolism were studied. The cells metabolized both phenylalanine and leucine under strict anaerobic conditions and produced hydroxylated products (i.e. phenyllactate from phenylalanine and hydroxyisocaproate from leucine). Other products were phenylpropionate, cinnamate and phenylacetate from phenylalanine; isocaproate, alpha-ketoisocaproate and isovalerate from leucine. Metronidazole inhibited the production of all end-products, with the exception of phenyllactate and hydroxyisocaproate which were increased. Similarly, when the reaction was carried out aerobically, the cells also metabolized both phenylalanine and leucine and all end-products were inhibited again with the exception of phenyllactate and hydroxyisocaproate. Our results suggest that the inhibitory mode of metronidazole is similar to that of oxygen.

Anaerobiosis↗

PubMed1994

Case report: anaerobic meningitis caused by Peptostreptococcus magnus after head and neck surgery.

Although anaerobic bacterial meningitis is uncommon, patients subjected to resection of head and neck malignancy appear at special risk. In this article, the authors report on a 72-year-old man in whom meningitis developed after extensive resection of the right sinuses for squamous cell carcinoma; initial treatment consisted of intravenous vancomycin and ceftazidime. Intravenous penicillin G was added after the fortuitous early finding of intracellular cocci in Wright-Giemsa stained cerebral spinal fluid submitted for cell count. Cerebral spinal fluid cultures then grew out a pure culture of Peptostreptococcus magnus. The patient had a complete recovery, without neurologic sequelae, recurrence of malignancy, or evidence of infection. Appropriate handling of cerebral spinal fluid specimens is crucial to ensure the correct diagnosis when anaerobic organisms are suspected.

Aged↗

PubMed2003

Peptostreptococcus micros in primary endodontic infections as detected by 16S rDNA-based polymerase chain reaction.

A 16S rDNA-based polymerase chain reaction (PCR) method was used to detect Peptostreptococcus micros in primary root canal infections. Samples were collected from 50 teeth having carious lesions, necrotic pulps, and different forms of periradicular diseases. DNA extracted from the samples was amplified using the PCR assay, which yielded a specific fragment of P. micros 16S rDNA. P. micros was detected in 6 of 22 root canals associated with asymptomatic chronic periradicular lesions (27.3%), 2 of 8 teeth with acute apical periodontitis (25%), and 6 of 20 cases of acute periradicular abscess (30%). In general, P. micros was found in 14 of 50 cases (28%). There was no correlation between the presence of P. micros and the occurrence of symptoms. Findings suggested that P. micros can be involved in the pathogenesis of different forms of periradicular lesions.

Adolescent↗

PubMed1990

Peptostreptococcus hydrogenalis sp. nov. from human fecal and vaginal flora.

We describe Peptostreptococcus hydrogenalis sp. nov., which is found in human feces and vaginal discharge. This new species was established on the basis of the results of DNA-DNA hybridization among anaerobic cocci. The results of different biochemical reactions also are given. The type strain of this species is strain GIFU 7662 (= JCM 7635).

Base Composition↗

PubMed1993

Description of two morphotypes of Peptostreptococcus micros.

Peptostreptococcus micros is often isolated from abscesses in several parts of the human body. The oral cavity is considered the natural habitat for the species, which has been implicated as a periodontal pathogen. In plaque samples from periodontitis patients we observed the presence of a rough morphotype of P. micros in addition to the previously recognized smooth morphotype. The rough morphotype has not been described previously. Both morphotypes are frequently isolated simultaneously from the same patient. In this paper strains of both morphotypes are described. The smooth morphotype, represented by the type strain, grew as small, dome-shaped, bright white, nonhemolytic colonies. The rough morphotype grew as equally white dry colonies which were hemolytic and had wrinkled edges. DNA-DNA reassociation studies revealed homology at the species level between the two morphotypes; in addition, no differences in physiological characteristics were observed when the organisms were tested with API-32A and API-ZYM kits. The rough cells had long, thin fibrillar structures outside the cell envelope when they were stained negatively for electron microscopy. In the smooth morphotype these structures were not present. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles of whole-cell extracts were different for the two morphotypes. In xylene-water phase partition studies, the smooth morphotype was found to be hydrophobic, whereas the rough morphotype was found to be relatively hydrophilic. The distinct morphotypes were stable on blood agar; however, the rough morphotype changed to a nonfibrillar type with a smooth colony morphology after repeated subculturing in broth.

Animals↗

PubMed1995

Phylogenetic analysis of Ruminococcus flavefaciens, the type species of the genus Ruminococcus, does not support the reclassification of Streptococcus hansenii and Peptostreptococcus productus as ruminococci.

The 16S rRNA gene sequence of the type strain of Ruminococcus flavefaciens, the type species of the genus Ruminococcus, was determined by PCR direct sequencing. A comparative sequence analysis showed that R. flavefaciens is phylogenetically related to a small cluster (cluster IV of Collins et al. [M. D. Collins, P. A. Lawson, A. Willems, J. J. Cordoba, J. Fernandez-Garayzabal, P. Garcia, J. Cai, H. Hippe, and J. A. E. Farrow, Int. J. Syst. Bacteriol. 44:812-826, 1994]) of organisms which includes several Clostridium and Eubacterium species. R. flavefaciens was found to be phylogenetically only remotely related to Ruminococcus gnavus, Ruminococcus torques, Peptostreptococcus productus, and Streptococcus hansenii. These findings demonstrate that the genus Ruminococcus is not a monophyletic group, and the proposed transfer of P. productus and S. hansenii to this genus (T. Ezaki, N. Li, Y. Hashimoto, H. Miura, and H. Yamamoto, Int. J. Syst. Bacteriol. 44:130-136, 1994) is not supported.

Base Sequence↗

PubMed1997

Characterization of smooth and rough morphotypes of Peptostreptococcus micros.

Isolation of the smooth (Sm) morphotype of Peptostreptococcus micros, a suspected oral pathogen, is sometimes accompanied by isolation of a rough (Rg) morphotype of P. micros. The Rg type readily changes to a Sm-like variant (RgSm) in broth culture. Sm and Rg isolates and RgSm variants were compared to determine whether these three types are the result of phase variation. The RgSm variants resembled the Sm morphotype in colony morphology; furthermore, the Sm type and the RgSm type did not have the fibrillar surface structures characteristic of the Rg type, and the Sm and RgSm types were more hydrophobic than the Rg type. However, when we compared the sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns of whole-cell proteins, serotyping data, pyrolysis mass spectrometry data, 16S ribosomal DNA sequences, and hemolytic activities, the RgSm variants and the Rg isolates were very similar and were clearly distinct from the Sm isolates. These results suggest that the Rg and RgSm types form a cluster distinct from the Sm type and thus provide evidence that P. micros can be differentiated into two groups, one consisting of the Sm type and the other consisting of the Rg and RgSm types.

Base Sequence↗

PubMed1984

Characterization of Peptostreptococcus asaccharolyticus glutamate dehydrogenase purified by dye-ligand chromatography.

Glutamate dehydrogenase (L-glutamate:NAD+ oxidoreductase (deaminating); EC 1.4.1.2) has been purified from Peptostreptococcus asaccharolyticus in a single step using dye-ligand chromatography. The enzyme (GDH) was present in high yields and was stabilized in crude extracts. A subunit molecular weight of 49000 +/- 500 was determined by SDS polyacrylamide gel electrophoresis and six bands were obtained after cross-linking the subunits with dimethyl suberimidate. This bacterial GDH was predominantly NAD+-linked, but was able to utilize both NADP+ and NADPH at 4% of the rates with NAD+ and NADH, respectively. An investigation of the amino acid specificity revealed some similarities with GDH from mammalian sources and some clear differences. The values of apparent Km for the substrates ammonia, 2-oxoglutarate, NADH, NAD+ and glutamate were 18.4, 0.82, 0.066, 0.031 and 6 mM, respectively. The P. asaccharolyticus GDH was not regulated by purine nucleotides, but was subject to strong inhibition with increasing ionic strength.

Chromatography, Agarose↗

PubMed1986

Immunochemical characterization of the cell surface carbohydrate antigens of Peptostreptococcus anaerobius.

Two carbohydrate antigens were isolated from the cell surface of Peptostreptococcus anaerobius. One, extracted from purified cell walls with NaOH, contained glucose and phosphorus, with traces of galactosamine and glucosamine. Serological activity was detected by a 'dot blot' procedure. The second antigen, extracted from cell membranes with phenol and purified by chromatography on Sepharose 6B and an immunoadsorbent column, contained glucose, glycerol phosphate, phosphorus and fatty acids. Antigenicity of this extract could also be demonstrated by an ELISA technique.

Antigens, Surface↗

PubMed1992

Physico-chemical and structural properties of the surfaces of Peptostreptococcus micros and Streptococcus mitis as compared to those of mutans streptococci, Streptococcus sanguis and Streptococcus salivarius.

The surface properties of nine Streptococcus mitis and four Peptostreptococcus micros strains from the oral cavity were examined and compared with a large group of oral streptococci. Zeta potential and contact angle measurements were employed to determine physico-chemical cell surface properties. In addition, elemental surface concentration ratios were obtained via X-ray photoelectron spectroscopy, and surface structures were examined with transmission electron microscopy. The S. mitis and P. micros strains were found to have higher isoelectric points, higher hydrophobicities and higher N/C surface concentration ratios than some other oral streptococci. The combined data suggest that both species possess large amounts of surface protein. All the S. mitis strains displayed abundant surface fibrils in negative staining, but the P. micros strains were devoid of surface appendages indicating that surface protein is present in different forms in the two species. The surfaces of S. mitis and P. micros type strains differed significantly from the other strains examined.

Bacterial Adhesion↗

PubMed1983

Effect of glucose concentration in the growth medium upon neutral and acidic fermentation end-products of Clostridium bifermentans, Clostridium sporogenes and peptostreptococcus anaerobius.

Clostridium bifermentans, C. sporogenes and Peptostreptococcus anaerobius were grown in Fastidious Anaerobe Broth with glucose concentrations from 0-1.5% (w/v). Gas chromatographic (GLC) analysis of fermentation end-products revealed that a change in glucose concentration markedly affected fermentation patterns of each microorganism. Increased glucose concentration resulted in stimulation of ethanol production by all strains, and of butanol and butyric acid by C. sporogenes. With C. bifermentans, there was a parallel increase in ethanol and acetic acid production and decreased formation of propanol and propionic, iso-butyric and iso-valeric acids. Increased ethanol formation by P. anaerobius was accompanied by an increase in acetic acid and a decrease in butan-1-ol production. The greatest incremental change in GLC profiles occurred when glucose concentration was raised from zero to 0.1% (w/v). These data suggest that glucose concentration in a medium for GLC analysis must be rigorously controlled if reproducible results are to be obtained.

Chromatography, Gas↗

PubMed2000

Crystallization and preliminary X-ray diffraction studies of mutants of B1 IgG-binding domain of protein L from Peptostreptococcus magnus.

The small 62-residue IgG-binding domain B1 of protein L from Peptostreptococcus magnus (Ppl-B1) has proven to be a simple system for the study of the thermodynamics and kinetics of protein folding. X-ray diffraction studies have been initiated in order to determine how the thermostability, folding and unfolding rates of a series of point mutations spanning Ppl-B1 correlate with the high-resolution structures. To this end, a tryptophan-containing variant of Ppl-B1 (herein known as wild type) and two mutants, Lys61Ala and Val49Ala, have been crystallized. Full data sets have been collected for the wild type and the Lys61Ala and Val49Ala mutants to resolutions of 1. 7, 2.3 and 1.8 A, respectively. Interestingly, all three crystallize using different precipitants and in different space groups. This may be a consequence of the relatively large effects of single-site mutations on surface-charge distribution or structural conformation, which might affect crystal contact sites.

Alanine↗

PubMed2004

The microbial synergy of Peptostreptococcus micros and Prevotella intermedia in a murine abscess model.

This study characterized the microbial interaction of Peptostreptococcus micros and Prevotella intermedia, the major pathogens of dentoalveolar infection, using a murine model. Subcutaneous injection of P. micros cells in the dorsum of the mouse together with living cells of P. intermedia resulted in a significantly larger abscess when compared with single injection of the organisms (P < 0.02). The abscess size was also significantly increased (P < 0.05) when the plate-cultured cell suspension of P. micros was injected into mouse with the culture filtrate of P. intermedia. The heat-treated culture filtrate of P. intermedia also enhanced the virulence of P. micros. P. micros culture filtrate did not affect the virulence of P. intermedia. Interestingly, the virulence of P. micros appeared to be enhanced even when the culture filtrate of P. intermedia was injected at separate sites in the mouse. These results suggest that a heat-stable product or products of P. intermedia increase the virulence of P. micros indirectly by altering the host condition, whereas living cells of P. micros can directly enhance virulence of P. intermedia.

Abscess↗