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At least 199 records · Page 11Linked to original sources
PubMed2006

Proteinase activity of prevotella species associated with oral purulent infection.

Prevotella intermedia and Prevotella nigrescens are often regarded as principal causes of acute dentoalveolar infection; however, other species within the genus are also known to be associated with such infection. The aim of this study was to determine the in vitro proteolytic activity of these different Prevotella species that have been implicated with dentoalveolar infection. A total of 234 strains were obtained from pus specimens from dentoalveolar infection and from the plaque of healthy volunteers. Prevotella loescheii, Prevotella oralis, Prevotella melaninogenica, Prevotella buccae, and Prevotella denticola were all shown to have a proteolytic activity (8.5-10.5 x 10(-8) A-units) lower than that of P. intermedia and P. nigrescens (21.1-23.5 x 10(-8) A-units). In the case of P. loescheii, P. melaninogenica, and P. intermedia, the level of proteolytic activity for clinical strains was significantly (P < 0.05) higher than that recorded for commensal strains. Proteolytic activity for all species of Prevotella examined was inhibited by N-ethylmaleimide and phenymethylsulfonyl fluoride. This study suggests that Prevotella species associated with oral purulent infection produce cysteine and serine proteinases and that in certain species of Prevotella, the strains involved in infection exhibit higher proteolytic activity when compared with strains from healthy sites.

Bacteroidaceae Infections↗
PubMed2003

One case of gram-negative anaerobic spondylodiscitis with Prevotella intermedia.

We report the case of a 45-year-old woman with spondylodiscitis at L1/L2, communicating with paravertebral, intravertebral and bilateral psoas abscesses. Percutaneous computed tomography (CT)-guided abscess drainage and an intravenous antibiotic therapy with Imipenem were performed. After removing the drainage at 2 weeks, the patient was discharged at 4 weeks with normalized blood parameters, normal temperature, and without need for analgesics. The underlying bacterium in the case was a very rare gram-negative anaerobic bacterium: Prevotella intermedia.

Abscess↗
PubMed2005

A unique pair of GATC specific DNA methyltransferases in Mitsuokella multiacida.

Two GATC specific methylases together with Sau3AI isoschizomeric restriction endonuclease were partially characterized in Mitsuokella multiacida 46/5. This is the first report on the presence of solitary Dam methyltransferase alongside GATC specific restriction-modification system resulting in the unusual two-fold methylation of the GATC motifs.

Bacteroidaceae↗
PubMed2005

Role of calcineurin in Porphyromonas gingivalis-induced myocardial cell hypertrophy and apoptosis.

BACKGROUND AND OBJECTIVE: Periodontal pathogen Porphyromonas gingivalis (P. gingivalis) increased cardiomyocyte hypertrophy and apoptosis whereas Actinobaeillus actinomycetemcomitans and Prevotella intermedia had no effects. The purpose of this study is to clarify the role of calcineurin signaling pathway in P. gingivalis-induced H9c2 myocardial cell hypertrophy and apoptosis. METHODS: DNA fragmentation, nuclear condensation, cellular morphology, calcineurin protein, Bcl2-associated death promoter (Bad) and nuclear factor of activated T cell (NFAT)-3 protein products in cultured H9c2 myocardial cell were measured by agarose gel electrophoresis, DAPI, immunofluorescence, and Western blotting following P. gingivalis and/or pre-administration of CsA (calcineurin inhibitors cyclosporin A). RESULTS: P. gingivalis not only increased calcineurin protein, NFAT-3 protein products and cellular hypertrophy, but also increased DNA fragmentation, nuclear condensation and Bad protein products in H9c2 cells. The increased cellular sizes, DNA fragmentation, nuclear condensation, and Bad of H9c2 cells treated with P. gingivalis were all significantly reduced after pre-administration of CsA. CONCLUSION: Our findings suggest that the activity of calcineurin signal pathway may be initiated by P. gingivalis and further lead to cell hypertrophy and death in culture H9c2 myocardial cells.

Apoptosis↗
PubMedDate not supplied

Pyomyositis of the thigh due to Prevotella melaninogenica.

Pyomyositis is an uncommon infection in temperate climates, however, it is being more frequently reported among patients with diabetes or malignancy, or those who are immunocompromised. It is predominantly caused by Staphylococcus aureus, and rarely by Bacteroides species. Pyomyositis due to Prevotella melaninogenica has not previously been reported. We describe an elderly patient with pyomyositis of the thigh due to P. melaninogenica which was successfully treated by surgical incision and drainage in combination with metronidazole therapy.

Aged↗
PubMed1975

The bacteriology of acute pelvic inflammatory disease.

The bacteriology of acute pelvic inflammatory disease (PID) was studied in 20 patients by simultaneous cul-de-sac, cervical, and blood cultures with aerobic and fastidious anaerobic techniques. Cul-de-sac cultures were positive in 18 of 20 patients, while all 8 normal control subjects yielded negative results (p less than 0.0005, chi-square analysis). Anaerobic bacteria (predominatly Peptococcus and Peptostreptococcus) were present in 10 patients (59 per cent), and they were the exclusive isolates in 3 patients. N. gonorrhoeae was isolated only once from the cul-de-sac despite its presence in cervical specimens. There was poor correlation between cul-de-sac and cervical cultures. Cervical cultures yielded a variety of aerobic and anaerobic bacteria with an average of 3.8 organisms per specimen. N. gonorrhoeae was isolated in 13 patients (65 per cent). Only 19 per cent of cervical isolates were recovered by culdocentesis; similarly, only 31 per cent of cul-de-sac isolates were simultaneously isolated from the cervix. Blood cultures were uniformly negative. These data suggest that: (1) culdocentesis is a reliable technique for the bacteriologic diagnosis of acute PID, and (2) whereas the gonococcus may be important in initiating acute PID, its primary role appears to be paving the way for secondary invaders from the normal vaginal flora to gain access to the upper genital tract.

Aerobiosis↗
PubMed1985

The relationships between streptococcal species and periodontopathic bacteria in human dental plaque.

The existence of antagonistic and commensal relationships between microorganisms was investigated. The predominant cultivable flora in 172 plaque samples from active and non-active sites in 32 human subjects with destructive periodontitis was determined. The presence of putative periodontopathic organisms (Bacteroides gingivalis, Bacteroides intermedius, Bacteroides forsythus, Wolinella recta, Actinobacillus actinomycetemcomitans, and Eikenella corrodens) in a site was correlated with the absence of certain viridans streptococci (Streptococcus sanguis, Streptococcus uberis and Streptococcus intermedius), and vice versa. A strong commensal relationship was found between B. gingivalis and Strep. intermedius. The second study involved 3 subjects with intractable periodontitis whose plaque harboured large numbers of one or more of these periodontopathic organisms. This plaque contained fewer organisms capable of inhibiting the growth of the periodontopathic strains in vitro when compared with a clinically-healthy control subject. Intermediate levels of inhibitors were found in plaque taken from non-active lesions. The majority of inhibitors in plaque from the healthy control were viridans streptococci. Hydrogen-peroxide production by these organisms appears to be the principal mechanism of growth inhibition for periodontopathic organisms. Bacterial interactions may thus be causally related to both periodontal health and disease.

Actinobacillus↗
PubMed1990

Monoclonal antibodies for the detection of 'periodontopathic' bacteria.

The development of indirect immunofluorescence assays using MAbs as specific probes has made it possible to detect a variety of suspected periodontal pathogens in subgingival plaque, with exquisite sensitivity. The studies demonstrate high reproducibility of the results if different MAbs are used to assess the same bacterial species. Bacteroides forsythus, Bact. gingivalis, Bact. intermedius and Wolinella recta, but not Actinobacillus actinomycetemcomitans were found in sites of adult periodontitis with high prevalence but quite distinct degrees of colonization. The colonization levels of Bact. forsythus and Bact. gingivalis were significantly associated with the probing depth of the lesions. The investigations demonstrate the usefulness of serological analysis of plaque and indicate that several of the organisms implicated in the aetiology of periodontal diseases may be tolerated in high numbers in subgingival lesions, without periodontal destruction.

Actinobacillus↗
PubMed1987

Correlation of the turnover number of the ATP synthase in liposomes with the proton flux and the proton potential across the membrane.

The fluorescent indicator pyranine was used for recording the internal pH of liposomes. The proton permeability was deduced from the velocity of the internal pH increase which was caused by shifting the external pH from 7 to 9. From valinomycin titration of the proton permeability in the presence of internal and external KCl (0.1 M), the permeability coefficient of H+ (PH) was obtained as 10(-4) cm/s at 22 degrees C. The coefficient was twice this value with the ATP synthase isolated from Wolinella succinogenes present in the liposomal membrane (10 mg protein/g phospholipid). ADP and phosphate had no effect on the latter PH. The protonophore TTFB (5 mumol/g phospholipid) increased the PH by 3 orders of magnitude. The permeability coefficients of H+ and K+ were used for calculating the delta uH and the proton flux associated with the phosphorylation which was driven by gradients of H+ and K+. For the conditions of limiting permeability of K+, the following conclusions were drawn. (1) In the steady state of rapid ion flux, the electrical potential across the liposomal membrane as calculated according to the Goldman equation, is directed opposite to the corresponding Nernst potential which is calculated from the K+ gradient. (2) The maximum turnover numbers of phosphorylation require a delta uH of 200-220 mV across the liposomal membrane. These values of delta uH and the corresponding turnover numbers are close to those brought about by the bacterial electron transport and the coupled phosphorylation. (3) The velocity of phosphorylation is linearly related to the proton flux. The slope of the line can be explained on the basis of an H+/ATP ratio of approx. 3.

Arylsulfonates↗
PubMed1981

Recent trends in empyema thoracis.

One hundred and twenty-three patients with empyema thoracis presenting between 1968 and 1978 were studied. The predominant cause was pneumonia, with thoracic and gastrooesophageal surgery as the other important predisposing factors. 99 patients had received antibiotics before hospital admission and organisms were isolated from the empyema of 62 of these (63%). Of the 62 patients with organisms 39 (63%) had previously received an antibiotic appropriate to the sensitivity of the pathogen. Staph. aureus, Str. pneumoniae and anaerobes were the organisms most frequently found in empyemata following pneumonia, whilst Gram-negative enteric bacilli, the most frequently isolated organisms, were the predominant pathogens in postoperative cases. Following treatment with antibiotics alone or with closed chest drainage 29% of empyemata resolved but another 64% required subsequent surgery. The former group had a mean duration of symptoms of 2.8 (SE +/- 0.8) weeks before hospital treatment whereas the surgically treated group had symptoms for a mean period of 8.3 (SE +/- 1.5) weeks. 83% of patients who required thoracotomy had a history of more than four weeks at the time of admission. Thirty-six deaths were recorded, 11 of which were attributable to the empyema, giving an empyema mortality-rate of 9%. We conclude that with widespread use of antibiotics the nature of empyemata has changed and that those now seen are more often refractory to closed chest drainage, particularly if the history prior to hospital admission is longer than four weeks.

Adolescent↗
PubMed1992

Mechanism of action of D-galacturonan digalacturonohydrolase of Selenomonas ruminantium on oligogalactosiduronic acids.

The mechanism of action of the specific D-galacturonan digalacturonohydrolase [poly-(1----4)-alpha-D-galactosiduronate digalacturonohydrolase, EC 3.2.1.82] of Selenomonas ruminantium was investigated by using reducing-end [1-3H]-labeled oligogalactosiduronates having degree of polymerization 3-5 as the substrates. The reaction products, incorporation and distribution of radioactivity in products, and the frequency of oligogalactosiduronate bond-cleavage were quantitatively estimated as functions of the substrate concentration. An alternative cleavage of tri(D-galactosiduronate) occurred during the enzyme reaction, indicating the participation of some bimolecular mechanism in addition to unimolecular hydrolysis in the action of the enzyme. Unimolecular hydrolysis takes place at low initial concentration of the substrate. The shifted termolecular enzyme-substrate complex formation and the subsequent galactosyluronic transfer is the predominant mechanism in degradation of tri(D-galactosiduronate) at high concentration. Tetra(D-galactosiduronate) and penta(D-galactosiduronate) are degraded by unimolecular hydrolysis at low, as well as high concentration of the substrate.

Bacteroidaceae↗
PubMed1987

Comparative EPR studies on the nitrite reductases from Escherichia coli and Wolinella succinogenes.

Hexaheme nitrite reductases purified to homogeneity from Escherichia coli K-12 and Wolinella succinogenes were studied by low-temperature EPR spectroscopy. In their isolated states, the two enzymes revealed nearly identical EPR spectra when measured at 12 K. Both high-spin and low-spin ferric heme EPR resonances with g values of 9.7, 3.7, 2.9, 2.3 and 1.5 were observed. These signals disappeared upon reduction by dithionite. Reaction of reduced enzyme with nitrite resulted in the formation of ferrous heme-NO complexes with distinct EPR spectral characteristics. The heme-NO complexes formed with the two enzymes differed, however, in g values and line-shapes. When reacted with hydroxylamine, reduced enzymes also showed the formation of ferrous heme-NO complexes. These results suggested the involvement of an enzyme-bound NO intermediate during the six-electron reduction of nitrite to ammonia catalyzed by these two hexaheme nitrite reductases. Heme proteins that can either expose bound NO to reduction or release it are significant components of both assimilatory and dissimilatory metabolisms of nitrate. The different ferrous heme-NO complexes detected for the two enzymes indicated, nevertheless, their subtle variation in heme reactivity during the reduction reaction.

Bacteroidaceae↗
PubMed1990

Spectroscopic studies of partially reduced forms of Wolinella succinogenes nitrite reductase.

Reductive titrations of the dissimilatory hexa-haem nitrite reductase, Wolinella succinogenes, with methyl viologen semiquinone (MV) and sodium dithionite, have been followed at room temperature by absorption, natural (CD) and magnetic circular dichroism (MCD) spectroscopies and at liquid helium temperature by electron paramagnetic resonance (EPR) and MCD spectroscopies. The nature of the reduced enzyme depends on the reductant employed. At room temperature a single high-spin ferrous haem, observed by MCD after reduction with MV, is absent from dithionite reduced samples. It is suggested that a product of dithionite oxidation becomes bound with high affinity to the reduced state of the enzyme causing the ferrous haem to become low-spin. The site occupied is likely to be the substrate binding haem. The course of the titration with MV at room temperature shows the reduction of high-spin ferric to high-spin ferrous haem. Since the EPR spectrum reveals the presence of an unusual high-low spin ferric haem pair in the oxidised state we propose that the active site of the enzyme is a novel haem pair consisting of one high (5-coordinate) and one low-spin (6 coordinate) haem, magnetically coupled and possibly bridged by a histidinate ligand.

Bacteroidaceae↗
PubMed1990

Regulation of the hexaheme nitrite/nitric oxide reductase of Desulfovibrio desulfuricans, Wolinella succinogenes and Escherichia coli. A mass spectrometric study.

Dissimilatory nitrite reduction, carried out by hexaheme proteins, gives ammonia as the final product. Representatives of this enzyme group from 3 bacterial species can also reduce NO to either ammonia or N2O. The redox regulation of the nitrite/nitric oxide activities is discussed in the context of the denitrifying pathway.

Ascorbic Acid↗