bluuebunny/crossref_metadata_2025 huggingface dataset:
Activity of metronidazole and its hydroxy metabolite against clinical isolates of Actinobacillus actinomycetemcomitans
Authors: Jousimies‐Somer Hannele , Asikainen Sirkka , Suomala Päivi , Summanen Paula
Published: December 2007

The in vitro susceptibility of Actinobacillus actinomycetemcomitans to metronidazole and its hydroxy metabolite was determined by the agar dilution method with 73 A. actinomycetemcomitans strains, recent clinical isolates from 13 patients with localized juvenile periodontitis. The minimal inhibitory concentrations (MICs) for 50% and for 90% of the isolates were, respectively, 16 μg/ml and 32 μg/ml of metronidazole, and 4 μg/ml and 8 μg/ml of the hydroxy metabolite. Although the MICs of the hydroxy metabolite were lower than those of the parent compound, the presently used dosage of metronidazole in treatment of periodontal diseases may not result in sufficiently high drug levels in gingival crevice fluid or in plasma to inhibit all A. actinomycetemcomitans strains. However, the known synergistic and additive effects of these compounds may increase the clinical efficacy of metronidazole in the treatment of periodontal infections associated with A. actinomycetemcomitans.
Opsonic IgG antibody against Actinobacillus actinomycetemcomitans in localized juvenile periodontitis
Authors: Baker Pamela J. , Wilson Mark E.
Published: December 2007

Actinobacillus actinomycetemcomitans is a gram‐negative bacterium frequently recovered from periodontal lesions of patients with localized juvenile periodontitis (LJP). Elevated levels of serum IgG and IgM antibodies to A. actinomycetemcomitans antigens are frequently observed in LJP patients, although the functional properties of such antibodies have not been characterized systematically. In this study, we analyzed serum from LJP subjects infected with A. actinomycetemcomitans with respect to the presence of IgG antibodies expressing opsonic, bactericidal and/or leukotoxin‐neutralizing activity against this organism. The IgG fractions obtained from serum of 3 LJP patients with elevated antibody liters to A. actinomycetemcomitans contained opsonic activity against a non‐leukotoxic Y4 strain, as well as for a highly leukotoxic JP2 strain. Opsonic activity required the presence of complement. The IgG fractions of pooled normal serum and serum from a fourth LJP subject with minimal ELISA‐reactive IgG antibody against this organism lacked detectable opsonic activity. Leukotoxic‐neutralizing IgG antibodies, although variably present, did not influence neutrophil killing of the leukotoxic JP2 strain. None of the sera tested contained bactericidal IgG antibodies capable of promoting direct complement‐mediated killing of A. actinomycetemcomitans. These results indicate that LJP subjects infected with A. actinomycetemcomitans are capable of producing opsonic IgG antibodies which may facilitate neutrophil‐mediated host defense against this periodontopathic organism.
Transfer of plasmid pE5‐2 from Escherichia coli to Bacteroides gingivalis and B. intermedius
Authors: Progulske‐Fox Ann , Oberste Anna , Drummond Charles , McArthur William P.
Published: December 2007

A unique shuttle plasmid, pE5‐2, previously constructed to mediate gene transfer from Escherichia coli to colonic Bacteroides spp. has also been transferred via conjugation from E. coli to isolates of Bacteroides gingivalis and B. Intermedius. The transfer occurred at a frequency of 1.4 to 2 × 10‐7 per recipient. The presence of the plasmid in transconjugants was verified by hybridization of the total DN A of B. gingivalis recipients with sequences of the pE5‐2 plasmid, as well as by standard plasmid isolation techniques.
Characterisation of monoclonal antibodies to common protein epitopes on the cell surface of Streptococcus mutans and Streptococcus sobrinus
Authors: Smith Roberta , Lehner T
Published: December 2007

Three monoclonal antibodies (MAb) were prepared against a cell surface antigen which cross‐react between Streptococcus mutans (serotypes c, e and) and Streptococcus sobrinus (serotypes d and g). Two of the MAb also recognise a determinant on the surface of Streptococcus cricetus (serotype a). The common antigen shared between S. mutans and 5. sobrinus was demonstrated by Western blotting to be about 200 kD in size. This antigen is shared not only by the cell surfaces of serotypes a, c, d, e, f and g, but also by the major cell surface antigen of S. mutans of 185 kD and another of 150 kD. These MAb identify all but one mutans type of streptococci and can be utilised as analytical reagents.
Characterization of selected gram‐negative oral microorganisms by SDS‐PAGE
Authors: Kinder Susan A. , Kornman Kenneth S. , Holt Stanley C.
Published: December 2007

SDS‐PAGE analysis of bacterial cell proteins was used to examine a diverse group of oral microorganisms. Most of the species examined, including physiologically similar microorganisms, produced distinct protein patterns which are characterized by the distribution of their major protein bands. The SDS‐PAGE system described provides a rapid, simple and standardized identification technique to be used in consort with routine taxonomic procedures.
Humoral immunity in root caries in an elderly population. II.
Authors: Butler John E. , Spradling Jill E. , Rowat J. , Ekstrand J. , Challacombe S. J.
Published: December 2007

Saliva specimens stored for 18 months at ‐20°C with or without glycerol and the anti‐protease benzamidine‐HCl, lost all antibody activity for S. mutans. IgA activity in processed whole saliva decreased significantly after one week when stored either at 4°C or ‐20°C with or without glycerol, although it was stable in parotid saliva for at least 40 days. Loss of activity prior to processing was significant in the first 24 h, and the addition of 50% glycerol and storage at ‐70° after processing, prevented loss of antibody activity in both whole and parotid saliva. Diurnal variations in IgA, lactoferrin and the IgA secretion rate were insignificant in parotid saliva but showed some fluctuations in whole saliva. Albumin and lactoferrin levels exhibited the greatest fluctuation in whole saliva specimens although IgA and IgA antibody levels were still more characteristic of the patient than the time of sampling. Monthly variations in IgA, IgA antibody activity and other parameters were least in parotid saliva and e.g., values for parameters that were high in patients samples on the first month, remained high during the 4‐month study period. Statistical analyses showed a high correlation between values obtained for most of the 15 parameters that were measured in parotid and whole saliva specimens collected from > 20 patients during 2 successive visits. Whole saliva values for albumin, lactoferrin and albumin levels in parotid saliva, were most variable but differences were not significant. Hence, patients with very low or very high values, even in whole saliva, can be identified within the population on the basis of specimens collected at a single time.
Production of volatile sulfur compounds by various Fusobacterium species
Authors: Claesson Rolf , Edlund Maj‐Britt , Persson Sten , Carlsson Jan
Published: December 2007

In 12 species of Fusobacterium the following characteristics were studied; the desulfhydration of L‐cysteine and L‐methionine by resting cell suspensions, the formation of a‐keto acids from L‐cysteine, D‐cysteine and L‐methionine by cell extracts, and the formation of hydrogen sulfide from L‐cysteine, D‐cysteine and L‐cystine by cell extracts separated by polyacrylamide gel electrophoresis. Multiple forms of L‐cysteine desulfhydrase activity were found in most of the species. In some of them also D‐cysteine desulfhydrase activity was demonstrated. Seven of the species had high L‐methionine γ‐lyase activity. L‐cystine lyase activity was present in 5 of the specieis.
Streptococcus cricetus and Streptococcus rattus bind to different segments of collagen molecules
Authors: Liu Tianjia , Gibbons R. J. , Hay D. I.
Published: December 2007

Strains of Streptococcus cricetus and Streptococcus rattus exhibited striking differences in their ability to bind to different types of collagen. For example, S. cricetus AHT bound in highest numbers to hydroxyapatite (HA) treated with human type V collagen, while rat type I collagen was ineffective. In contrast, human type V collagen was least effective in promoting attachment of S. rattus LB‐1, while treatment with rat or human type I collagen was effective. Adsorption of both species to human type I collagen‐treated HA showed a high correlation with a Langmuir model. Estimates of adsorption parameters indicated there were greater numbers of binding sites with higher affinity for S. rattus LB‐1 than for S. cricetus AHT. Treatment of HA with either the alpha 1 (1) or alpha 2 (1) polypeptide chains of collagen was effective in promoting adhesion of S. rattus LB‐1 cells. In contrast, the alpha 2(1) chain was more effective than the alpha 1 (1), chain for S. cricetus AHT. These observations indicate that S. cricetus AHT and S. rattus LB‐1 cells bind to different segments of collagen molecules. Adhesion of both species was also promoted by collagen‐rich fractions of human dentin.
Prevalence and antimicrobial susceptibility of Enterobacteriaceae, Pseudomonadaceae and Acinetobacter in human periodontitis
Authors: Slots Jørgen , Feik Diane , Rams Thomas E.
Published: December 2007

This study examined the occurrence of non‐oral gram‐negative facultatively anaerobic rods in advanced adult periodontitis. Speciation and in vitro antimicrobial susceptibility testing was performed using the MicroScan micromethod system. A total of 42 taxa of Enterobacteriaceae, Pseudomonadaceae and Acinetobacter were isolated from 427 of 3,050 (14.0%) patients. In 159 (5.2%) patients, these organisms comprised more than 5% of the cultivable subgingival microflora. Enterobacter cloacae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Klebsiella oxytoca and Enterobacter agglomerans accounted for more than 50% of all strains isolated. Virtually all study strains demonstrated high in vitro susceptibility to ciprofloxacin, but exhibited variable susceptibility patterns to 18 other antimicrobial agents tested. In 3 “refractory” periodontitis patients heavily infected with enteric rods, systemic ciprofloxacin therapy (500 mg BiD for 10 days) led to resolution of the subgingival infections and improved clinical periodontal status. The present findings indicate that 5% of severe periodontitis lesions may harbor high levels of non‐oral, gram‐negative, facultatively anaerobic rods. Systemic ciprofloxacin appears to be capable of eradicating these potential pathogens from deep periodontal pockets.
Subgingival occurrence of enteric rods, yeasts and staphylococci after systemic doxycycline therapy
Authors: Rams Thomas E. , Babalola Oluwatoyin O. , Slots Jörgen
Published: December 2007

The occurrence of Subgingival enteric rods, yeasts and staphylococci (pre‐treatment and post‐treatment) was examined in 21 adult periodontitis patients receiving mechanical periodontal therapy and systemic doxycycline (200 mg on first day, then 100 mg/day for 20 days). Subgingival samples obtained prior to, and 2 weeks and 4 weeks after completion of the antibiotic therapy were transported in VMGA III and plated onto TSBV (for enteric rods and yeasts) and Staphylococcus 110 media. At baseline, small numbers of enteric rods (3 patients), yeasts (5 patients) and staphylococci (11 patients) were detected subgingivally. After the antibiotic therapy, more than 10‐fold increases were seen in subgingival numbers of Enterobacter aerogenes (2 patients), Eseherichia coli (1 patient), Candida albicans (2 patients), and staphylococci (11 patients). These findings demonstrating that systemic doxycline therapy may result in at least temporary subgingival overgrowths of enteric rods, yeasts and staphylococci, may indicate the risk of frequent use of tetracyclines in periodontal therapy.
Mutans streptococci in saliva and dental caries in children living in a high and a low fluoride area
Authors: Twetman Svante , Mattiasson Agneta , Varela Juliana R. , Bratthall Douglas
Published: December 2007

The aim of this study was to obtain information about the quantitative distribution of salivary mutans streptococci and the relation to dental caries in children with contrasting levels of natural water fluoride. A total of 698 schoolchildren aged 12 yr were selected from areas with high (1.2 ppm) or low (0.1 ppm) fluoride concentration in the drinking water. They were all examined for the presence and number of mutans streptococci in saliva by a specially prepared plastic strip, the “Strip mutans” method, cultivated in a selective broth. Data on the caries experience were obtained from the dental records and from bite‐wing radiographs. Mutans streptococci were identified in 82% of all children with no difference between the two areas. The number of mutans streptococci was however significantly (p<0.05) lower among the children from the high fluoride area than those from the low fluoride area. Children with no detectable or low levels (0‐10 CPU) of mutans streptococci had less caries experience than children with moderate or high levels (11–>500 CPU) in both areas investigated.
In vitro survival of Bacteroides intermedius in five transport media, alone or in the presence of Streptococcus sanguis
Authors: Deveaux Etienne , Delplanque Pascal , Neut Christel , Charon Jacques , Romond Charles
Published: December 2007

The survival rate of Bacteroides intermedius was first tested in monoculture, and Streptococcus sanguis was then added in 5 different transport media; 2 nonnutritious media, the viability‐preserving medium of the University of Göteborg No. IV (VMG IV), reduced transport fluid (RTF), and 3 nutritious media, thioglycolate medium (TG), peptone yeast extract medium (PY) and PY medium with 1% glucose (PYG). All manipulations were carried out in an anaerobic chamber. After a given transport time (6 or 24 h) aliquots were spread on plates containing solid PY medium by means of an automated spiral system device, thus permitting counts after incubation. The slight variations in the counts of B. intermedius in monoculture, not exceeding 0.5 log10 in the 5 media tested, indicated its good survival capability, i.e. at least 24 h. By contrast, when S. sanguis was added, it was only possible to use nutritious media such as PY or TG for 6 h. In the glucose‐containing media (PYG, TG), the multiplication of rapidly glucose‐fermenting microorganisms such as streptococci influenced the B. intermedius survival rate. Therefore, the transport time for oral microbiological samples needs to be reduced as much as possible. The use of excessively rich media (particularly media containing a high level of glucose) should be avoided.
pH‐dependent fluoride inhibition of catalase activity
Authors: Thibodeau Edward A. , Keefe Theresa F.
Published: December 2007

The inhibitory effects of fluoride on several catalases were examined over a range of pH conditions. Preparations of bovine‐liver catalase were sensitive to fluoride under acidic conditions. Catalase activity associated with whole‐cell preparations of Actinomyces viscosus NP 311A remained relatively constant between pH 3.0 and 8.0 and was inhibited by fluoride in a pH‐dependent manner. Fluoride was also observed to enhance hydrogen peroxide killing of A. viscosus NP 311A under acidic pH conditions. Results suggest that some catalase enzymes, including those associated with common plaque bacteria, may be inhibited by fluoride in a pH‐dependent manner.
Antimicrobial activities of thiolactomycin against gram‐negative anaerobes associated with periodontal disease
Authors: Hamada Shigeyuki , Fujiwara Taku , Shimauchi Hidetoshi , Ogawa Tomohiko , Nishihara Tatsuji , Koga Toshihiko , Nehashi Toshiyuki , Matsuno Takashi
Published: December 2007

Thiolactomycin (TLM), (4R)‐(2E, 5E)‐2,4,6‐trimethyl‐3‐hydroxy‐2,5,7‐octatriene‐4‐thiolide, purified from a culture filtrate of a strain of the Nocardia species, was examined for antimicrobial activities against more than 100 strains of oral and periodontally associated bacteria. Nine other commonly used antibiotics were also included for the test. We found that TLM exhibited strong and selective antimicrobial activities against Bacteroides gingivalis and other oral black‐pigmented Bacteroides species that may be etiologically associated with adult periodontitis. TLM also inhibited the growth of Actinobacillus actinomycetemcomitans, but did not affect the growth of oral streptococcal species and Eubacterium species. Strains of Eikenella corrodens were moderately susceptible to TLM, while Actinomyces viscosus strains were only slightly susceptible to it. Other antibiotics used for comparison showed a broad spectrum of antimicrobial activities in general. In conclusion, TLM exhibited highly selective antimicrobial activities to black‐pigmented Bacteroides species and A. actinomycetemcomitans, both of which are implicated in the pathogenesis of human periodontal disease.
Parameters affecting the inhibition of Candida albicans GDH 2023 and GRI 2773 blastospore viability by purified synthetic salivary histidine‐rich polypeptides
Authors: Santarpia R. P. , Cho M.I. , Pollock J. J.
Published: December 2007

Purified synthetic salivary histidine‐rich polypeptides, HRPs 2, 3, 4, 5, and 6, were observed to inhibit Candida albicans blastospore viability at yeast cell concentrations ranging from 102 to greater than 106 colony forming units per ml. Among the HRPs, HRP‐4 was the best inhibitor with significant killing activity noted at a peptide concentration of 0.5 μg per ml. Antifungal potency under growth conditions was observed to be dependent upon pH. In contrast, killing did not vary throughout the pH range tested under non‐growth conditions. Electron microscopy results demonstrated HRP damage at pH 5 which appeared to be initiated at the membrane. At pH 7.4, micrographs revealed clear evidence of intracellular destruction suggesting more extensive damage at neutral as compared to acidic pH. These results suggest that within the changing realm of the oral cavity, the HRPs would be expected to be potent killers of C. albicans.
Binding of Actinomyces viscosus to collagen: association with the type 1 fimbrial adhesin
Authors: Liu T. , Gibbons R. J. , Hay D. I. , Skobe Z.
Published: December 2007

Treatment of hydroxyapatite (HA) with human type I or type III collagen strongly promoted adhesion of Actinomyces viscosus LY7 cells. Treatment with human type V collagen was somewhat less effective while treatment with human type IV or rat type I collagen was significantly less effective. Electron microscopic observations revealed that A. viscosus cells also attached to fibrils prepared from human type I collagen. The alpha 1 (1) polypeptide chain derived from type I collagen was ineffective in promoting binding and the alpha 2(1) polypeptide chain exhibited moderate activity. Heat‐ or urea‐denatured type I collagens were also ineffective in promoting binding. Mutants of A. viscosus that possess type 1 fimbriae, but not type 2 fimbriae or no fimbriae, also bound to collagen‐treated HA; this suggests that the adhesin responsible was associated with type 1 fimbriae. Strains of Actinomyces israelii and Actinomyces odontolyticus also exhibited strong binding to collagen‐treated HA, while Actinomyces naeslundii ATCC 12104 did not. The avidity of Actinomyces species for collagen would seem to be at least partially responsible for the high proportions of these organisms found on cemental and root tooth surfaces.
Preserving the motility of microorganisms
Authors: Petit M. D. A. , Van der Velden U. , Van Winkelhoff A. J. , De Graaff J.
Published: December 2007

This study focused on several factors that may influence the percentage of motile microorganisms in a sample from the tongue determined using a phase‐contrast microscope. It was found that the time elapsing between sampling and analysis is crucially important. In both sterile saline and reduced transport fluid (RTF), a reduction of the percentage of motile microorganisms was found within 15–30 min after sampling respectively. In order to be able to prolong the time interval between sampling and analysis, it was found that storing a sample in a tuberculin syringe with RTF supplemented with Fildes extract preserved the motility of the microorganisms and gave no significant reduction in the percentage of motiles within 48 h.
Distribution of Actinobacillus actinomycetemcomitans serotypes in periodontal health and disease
Authors: Asikainen S. , Lai C‐H. , Alaluusua S. , Slots J.
Published: December 2007

A total of 177 Actinobacillus actinomycetemcomitans isolates from 136 periodontally healthy or diseased subjects were serotyped by indirect immunofluorescence and/or immunodiffusion assays. Serotype‐specific rabbit antisera against A. actinomycetemcomitans serotypes a, b and c were used. All 3 serotypes were commonly found in the study subjects. Serotype b was dominant in subjects with Periodontal disease and serotype c was the most common serotype in the healthy subjects. In the immunofluorescence assay, when 85 isolates were cultured anaerobically and fixed in acetone, or cultured aerobically in 10% CO2 and heat‐fixed, 60 isolates revealed the same serotypes. The remaining 25 isolates reacted with 2 of the serotype‐determining reagents. In the immunodiffusion assay, 22 of these 25 isolates reacted with one antiserum only. These results suggest differences in the distribution of A. actinomycetemcomitans serotypes between periodontal health and disease and point to possible variation in serotype determination due to bacterial growth and preparation procedures.
Sorbitol transport by Streptococcus sanguis 160
Authors: Svensater G. , Hamilton I. R.
Published: December 2007

Sorbitol metabolism was examined with a sorbitol‐fermenting strain (160) of Streptococcus sanguis isolated from the dental plaque of a subject using sorbitol‐containing chewing‐gum for 4 years. S. sanguis 160 was grown in continuous culture (pH, 7.0; dilution rate, 0.1 h−1) with glucose, sorbitol and nitrogen (sorbitol‐excess) limitations. Cells grown with a glucose limitation exhibited low, but detectable, uptake of [14C]‐sorbitol and transition to medium limiting in sorbitol resulted in a 5‐fold increase in sorbitol uptake. Kinetic data revealed that both glucose and sorbitol‐limited cells possessed 2 transport systems for sorbitol (Ks= 3.3–6.7 and 36–64 μM), but continued growth of the organism on limiting sorbitol resulted in the loss of the high‐affinity system. Decryptified, sorbitol‐limited cells phosphorylated sorbitol in the presence of phosphoenolpyruvate (PEP), but not with ATP, indicating sorbitol transport solely via the PEP phosphotransferase (PTS) system. PEP‐dependent activity in glucose‐limited and sorbitol‐excess cells was 6‐ and 4‐fold lower than that of the sorbitol‐limited cells. Uptake of [14C]‐sorbitol and activity for Ell for sorbitol [E11sor] of the PTS in cells in transition from a glucose to sorbitol limitation confirmed the induction of the sorbitol‐PTS and the repression of the glucose‐PTS in the presence of sorbitol. Cells grown with an excess of sorbitol exhibited very low EIIsor activity. A crossover experiment with membranes and soluble fractions from glucose‐, sorbitol‐ and nitrogen‐limited cells of S. sanguis 160 demonstrated the induction of a soluble PTS component in sorbitol‐limited cells essential for sorbitol transport via the PTS. In addition, this factor, tentatively identified as lllsor, was shown to stimulate 7‐fold sorbitol phosphorylation by glucose‐limited membranes, indicating the possibility that sorbitol can be transported via Ellglc in the presence of the sorbitol‐specific, soluble component. This observation was confirmed by demonstrating that glucose and sorbitol compete for 1 of the 2 sorbitol transport systems in the organism. Our results indicate that transition of S. sanguis 160 from glucose to sorbitol‐limited growth results in sorbitol transport initially via Ellglc and a sorbitol‐specific soluble factor (lllsor) and this is followed by the relatively slow induction of Ellsor and the concomitant repression of E11glc.
Antineoplastic agents inhibit the growth of Streptococcus mutans and Streptococcus sanguis in vitro
Authors: Meurman Jukka H. , Torkko Heini , Pyrhönen Seppo
Published: December 2007

The effect of methotrexate (MTX) and doxorubicin on the growth, metabolism and ultrastructure of Streptococcus mutans and Streptococcus sanguis was studied in vitro. Both anticancer drugs exerted an inhibitory effect on the oral streptococci. MTX was more inhibitory than doxorubicin. The minimum inhibitory concentrations (MICs) of MTX to S. mutans were 0.25–2.5 μg/ml and that of doxorubicin 0–2 mg/ml. The MICs of MTX and doxorubicin to S. sanguis were 0.025 μg/ml and 2.0–0.02 mg/ml, respectively. When saliva samples of patients with malignant tumors receiving various doses of MTX were analyzed, MTX was found to be secreted into the oral cavity at concentrations ranging from 0.014 to 4.486 μg/ml. The saliva of these patients was also found to inhibit the growth of S. mutans, and the inhibition zones were in accordance with the MIC values observed. The results suggest that anticancer therapy must be taken into account when the salivary microbiological findings of cancer patients are interpreted.
Degradation of plasma proteins by the trypsin‐like enzyme of Porphyromonas gingivalis and inhibition of protease activity by a serine protease inhibitor of human plasma
Authors: Fishburn C. S. , Slaney J. M. , Carman R. J. , Curtis M. A.
Published: December 2007

The interaction between Porphyromonas gingivalis culture supernatant and human serum was examined. Hydrolysis of the major serum proteins was thiol‐dependent and correlated with the trypsin‐like activity of the sample. Transferrin and IgG light chains were less susceptible to degradation than albumin and IgG heavy chains and partially degraded IgG retained antigen‐binding capability. Serum inhibited the trypsin‐like activity in a fluorimetric assay. The inhibition was shown to be independent of the level of IgG antibody reactive with whole cells of P. gingivalis. Purified preparations of antithrombin III, a serine protease inhibitor, but not α1‐antitrypsin nor α2‐macroglobulin inhibited the trypsin‐like activity in the fluorimetric assay.
Adherence to experimental pellicle of rough‐type lipopolysaccharides from subgingival plaque bacteria
Authors: Okuda Katsuji , Kato Tetsuo , Ishihara Kazuyuki , Naito Yuko
Published: December 2007

The adherence of lipopolysaccharides (LPSs) from periodontal disease‐associated bacteria to saliva‐coated hydroxyapatite (S‐HA) and serum‐coated HA beads was examined by chromogenic Limulus activity (toxicolor test). Phenol‐water extracted LPS preparations from Bacteroides intermedius, Fusobacterium nucleatum, Actinobacillus actinomycetemcomitans, Eikenella corrodens, and rough‐type LPS from Escherichia coli adhered to S‐HA and serum‐coated beads and agglutinated human erythrocytes. The adhered LPSs to S‐HA and serum‐coated HA beads were not removed by vigorous washing with distilled water. LPSs from Bacteroides (Porphyromonas) gingivalis strains and wild‐type E. coli did not adhere to S‐HA, serum‐coated HA beads or show hemagglutinating activity. SDS‐PAGE patterns stained with silver stain showed that LPSs adhered to S‐HA, and serum‐coated HA beads and erythrocytes possessed a distinct fast‐migrating band similar to rough‐type LPS. B. gingivalis LPSs possessed slow‐migrating and repeating ladder bands similar to wild‐type LPS.
Aspects of the growth and metabolism of Fusobacterium nucleatum ATCC 10953 in continuous culture
Authors: Rogers A. H. , Zilm P. S. , Gully N. J. , Pfennig A. L. , Marsh P. D.
Published: December 2007

Fusobacterium nucleatum ATCC 10953, a type strain of one of the newly proposed subspecies of this group of organisms, was grown anaerobically in continuous culture in a chemically defined medium. Its response to conditions of varying pH, nutritional environment, and imposed growth rate were then examined. The organism failed to grow at pH 7.8 but grew at pH 5.8, although the cell yield was greatly reduced. At pH 6.8 the cell yield was halved and less than 50% of available glucose was consumed. The optimum growth pH was around 7.4 when the culture appeared to be limited for both glucose and the amino acids glutamate, histidine and serine. Some intracellular polyglucose (IP) was produced and acetate, butyrate and ammonia were the major fermentation end‐products, as they were under all growth conditions tested. Increasing the available glucose or amino acids did not alter cell numbers but the amount of IP was greatly increased. When glucose was omitted from the medium, the cell yield was halved and the culture then became limited for lysine as well as for glutamate, histidine and serine. Growth rate had little overall effect on the organism's physiology and the maximum growth rate at pH 7.4 was 0.20 h−1, a doubling time of 3.5 h. Glucose was thus channelled into stable IP synthesis only when the growth limitation imposed by lack of fermentable amino acids was relieved. The metabolism of IP and the ability to obtain carbon and energy from a variety of substrates may explain why F. nucleatum is one of the most commonly detected organisms in subgingival dental plaque.
Chain formation and de‐chaining in Streptococcus sobrinus SL‐1
Authors: Thibodeau Edward A. , Ford Charles M.
Published: December 2007

Regulation of chain length by chain‐forming bacteria is believed to depend on wall‐associated autolytic activity and environmental conditions. In this study, the chain length of Streptococcus sobrinus SL‐1 was determined under various initial culture and pH conditions and NaF concentrations. Crude wall extracts were prepared by dilute alkali treatment of whole cells and were tested for de‐chaining activity. The results indicate that S. sobrinus SL‐1 grows primarily as short chains under alkaline growth conditions and at high (3.0 mM) medium fluoride levels, and growth as long chains occurs under acidic growth conditions. De‐chaining activity was observed following incubation of the longer chain form of the organism with crude wall extracts. The evidence suggests that the chain length of S. sobrinus SL‐1 depends on environmental conditions, including pH and fluoride, and that cell wall‐associated factors may be active in regulating the chain length of the organism.
Distribution and immunochemical specificities of fimbriae of Porphyromonas gingivalis and related bacterial species
Authors: Ogawa Tomohiko , Mukai Tetsu , Yasuda Kenji , Shimauchi Hidetoshi , Toda Yoshihisa , Hamada Shigeyuki
Published: December 2007

Rabbit polyclonal antibody (Poly‐1) and mouse monoclonal antibodies (mAbs) TO‐11, TO‐14 and TO‐M1 specific for Porphyromonas gingivalis 381 fimbriae were prepared. Poly‐1 and the 3 mAbs were screened for their reactivity with whole cells of oral and nonoral black‐pigmented bacterial species by enzyme‐linked immunosorbent assay (ELISA) and the binding experiment using [125I] Poly‐1 and [125I] mAbs. ELISA revealed that Poly‐1 definitely reacted with whole cells of all the 11 strains of P. gingivalis tested. However, 8 of 11 P. gingivalis strains reacted with mAbs TO‐11, TO‐14 and TO‐M1. These results were confirmed by the specific binding of radiolabelled Poly‐1 and mAb TO‐11 to the 8 strains. The Mr of the fimbrial summit protein (fimbrilin) isolated and purified from P. gingivalis strains 381, BH18/10, HW24D‐1, 6/26 and OMZ 314 was 41 kDa by sodium dodecylsulfate‐polyacrylamide gel electrophoresis. It was found by immunoblotting that mAbs TO‐11 and TO‐14/TO‐M1 recognized different epitopes of fimbrial protein from P. gingivalis strains. visualized similar serotype‐specific antibody bindings to the fimbriae. These results indicate that 11 strains of P. gingivalis could be divided into at least 2 separate groups based on the immunochemical specificities of the fimbriae.
Sensitivity of Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus to oxidative killing
Authors: Dongari A. I. , Miyasaki K. T.
Published: December 2007

We examined the killing of Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus by oxygen metabolites generated by the xanthine‐xanthine oxidase (X‐XO) system. This system generates a mixture of oxidants, including superoxide radical, hydrogen peroxide, hydroxyl radical, and possibly singlet oxygen. Differential sensitivity to the X‐XO system was observed among strains of A. actinomycetemcomitans; notably, 2 catalase‐deficient strains and 2 strains representative of serotypes b and c were the most susceptible. H. aphrophilus was not sensitive. The amount of oxidants produced by the X‐XO system more closely correlated with killing than the ratio of oxidant production. Cytochrome c, superoxide dismutase, catalase, dimethyl sulfoxide, and desferrioxamine were used to determine the role of superoxide radical, hydrogen peroxide and hydroxyl radical in the bactericidal process. Hydrogen peroxide was the major bactericidal agent against A. actinomycetemcomitans. Superoxide anion participated in killing of A. actinomycetemcomitans to varying but lesser degrees. The intracellular generation of hydroxyl radical was implicated in the killing of several strains. We conclude that (i) strains of A. actinomycetemcomitans are differentially sensitive to the bactericidal effects of the X‐XO system and (ii) of the oxidants produced by the X‐XO system, hydrogen peroxide is the most bactericidal against A. actinomycetemcomitans.
Salivary anti‐candidal assays
Authors: Santarpia R. P. , Xu L. , Lal K. , Pollock J. J.
Published: December 2007

Inhibition of Candida albicans blastospore viability by parotid, submandibular‐sublingual and whole salivas could not be determined by direct assay of yeast cells in each respective saliva. Determination of antifungal activity could, however, be carried out if saliva was first preincubated with Candida cells and this was immediately followed by removal of saliva and resuspension of yeast cells in nonenriched buffers of pH 5‐7 for appropriate incubation periods. To attain accurate reproducible quantitative data, parotid, submandibular‐sublingual and whole salivas each required different preincubation times with C. albicans as well as prior acidification and boiling. Acidification was also necessary for optimizing the germ tube assay although, in contrast to blastospore viability, inhibition of blastospore‐germ tube conversion could be determined directly in saliva. Salivary antifungal effects on blastospore division were negligible at yeast cell concentrations greater than 106 colony‐forming units per ml and were found to be independent of pH, whereas salivary inhibition of germ tube formation was significant only at pH 5 in the assay systems employed. The requirement for acidification and an observed enhancement of antifungal activity on aqueous dilution of the saliva suggested that only a fraction of the salivary antifungal components present in saliva were available in the free form to exert their biological activity. These results open up the possibility of investigating salivary antifungal activity in human health and disease.
Enterococci in human periodontitis
Authors: Rams T. E. , Feik D. , Young V. , Hammond B. F. , Slots J.
Published: December 2007

Enterococci are potential pathogens in many human body sites. This study determined the subgingival occurrence and the in vitro antimicrobial susceptibility of enterococci in 100 persons with early‐onset periodontitis and 545 persons with advanced adult periodontitis. Subgingival microbial samples were collected with paper points, transported in VMGA III and plated onto anaerobic enriched brucella blood agar or selective Enterococcosel® agar (BBL Microbiology Systems). Enterococcal speciation was performed using commercial micromethod kit systems. In vitro sensitivity was determined using a commercial kit system and an agar dilution assay. Subgingival enterococci occurred in 1% of early‐onset periodontitis patients and in approximately 5% of adult periodontitis patients. Enter‐ococcus faecalis was the only enterococcal species recovered, and all but one isolate belonged to the same biotype. In vitro antimicrobial sensitivity testing revealed subgingival enterococci resistant to therapeutic levels of penicillin G, tetracycline, clindamycin and metronidazole, but relatively sensitive to ciprofloxacin and amoxicillin/potassium clavulanate (Augmentin®). Enterococci may populate periodontal pockets as superinfecting organisms and, in heavily infected patients, may contribute to periodontal breakdown.
A non‐lectin‐like mechanism by which Fusobacterium nucleatum 10953 adheres to and activates human lymphocytes
Authors: Tuttle Raymond S. , Strubel Naomi A. , Mourad Jamal , Mangan Dennis F.
Published: December 2007

Most (∼80%) strains of Fusobacterium nucleatum adhere to human erythrocytes in a lectin‐like manner that is strongly inhibited by N‐acetyl‐D‐galactosamine (GalNAc). In this study, we investigated the capacity of F. nucleatum 10953, a strain that is weakly inhibited by GalNAc, to adhere to and activate human lymphocytes in vitro. Experiments using [3H]‐labeled bacteria and scanning electron microscopy clearly showed that 10953 adhered to lymphocytes and that adherence was blocked by L‐arginine + GalNAc>L‐arginine> > GalNAc. Adherence was Ca2+‐dependent, inhibited by pretreatment of the bacteria with proteases or heat, and unaffected by paraformaldehyde fixation of the bacteria. Strain 10953 induced lymphocyte mitogenesis that was blocked by L‐arginine but not by GalNAc. These results suggest that certain strains of F. nucleatum, such as 10953, express a distinct, non‐lectin‐like mechanism by which they adhere to and activate lymphocytes. Activation of lymphocytes may be an important mechanism in the pathogenesis of periodontal diseases associated with these bacteria.
Histatins 2 and 4 are autoproteolytic degradation products of human parotid saliva
Authors: Xu L. , Lal K. , Pollock J. J.
Published: December 2007

Freshly collected human parotid saliva contains 8 cationic proteins, as demonstrated by capillary electrophoresis. These proteins include lysozyme, histatin 6 and the 6 salivary histidine‐rich polypeptides (HRPs 1–6). Neither histatin 2 nor histatin 4 are present in native undegraded parotid saliva but appear only after auloproteolytic degradation of the saliva. Histatin 2 appears to arise through slow degradation of HRP‐1, and histatin 4 is mainly produced as a rapid breakdown product of HRP‐3.
Assessment of the cariogenic potential of Streptococcus mutans strains and its relationship to in vivo caries experience
Authors: Macpherson L. M. D. , MacFarlane T. W. , Geddes D. A. M. , Stephen K. W.
Published: December 2007

Strains of Streptococcus mutans isolated from the plaque of 6 subjects were studied using an in vitro model to determine whether differences in their cariogenic potential could be detected, and if so, whether the results correlated with the caries experience of the individuals. Each strain was incubated with a bovine enamel slab and 5% (w/v) sucrose for 24‐h periods. The acidogenic potential was assessed by pH measurement and analysis of acid anion production. Microradio‐graphic and microdensitometric assessment of the enamel, together with measurement of the change in calcium concentration of the reaction mixture were used to determine the demineralizing potential of each strain. Significant differences in cariogenic potential were found between some of the strains tested, and correlations were found between 3 of the test parameters and the decayed‐missing‐filled‐surface score of the individuals. The results suggest that the caries experience of individuals may be related, to some extent, to the cariogenic potential of their S. mutans strains.
Characterization of shared antigens of Fusobacterium nucleatum and Fusobacterium necrophorum
Authors: Kaur M. , Falkler W. A.
Published: December 2007

Fusobacterium nucleatum and Fusobacterium necrophorum are gram‐negative, non‐spore‐forming anaerobic rods, frequently isolated from the normal flora and diseased lesions of the human oral cavity, gastrointestinal and genitourinary tracts. F. necrophorum is also known to be an animal pathogen. Studies were undertaken with rabbit anti‐F. nucleatum sera and with human adult periodontitis (AP) sera that demonstrated the sharing of antigens between the two species. Immunodiffusion and immunoelectrophoresis studies of Fusobacterium species with rabbit anti‐F nucleatum sera demonstrated the presence of shared antigen(s) between F. nucleatum and F. necrophorum. Adsorption studies of AP sera in an enzyme‐linked immunosorbent assay demonstrated the presence of antibodies reacting with the shared antigens of the two species. Immunoblot (IB) analysis of a soluble protein preparation of the two species of Fusobacterium, when allowed to react with rabbit anti‐F. nucleatum 10197 serum, demonstrated 53 kDa and 30 kDa bands present in members of the two species. Further, IB analysis of protein preparations of the two species with AP sera indicated the presence of antibodies reacting with the shared 53 kDa band and in some cases the 30 kDa band. During serological testing with antisera or host immune studies with human sera to these species, the presence of shared antigens must be considered.
Acid production by streptococci growing at low pH in a chemostat under anaerobic conditions
Authors: Iwami Y. , Abbe K. , Takahashi‐Abbe S. , Yamada T.
Published: December 2007

Streptococcus mutans and other oral streptococci were grown in continuous culture under strictly anaerobic conditions. When the cultural pH was kept at 7.0, the main acid products were formate and acetate, as reported previously. However, more lactate was produced at pH values of 5.5 or 6.0, with a concomitant decrease in formate and acetate production. This change in fermentation products could partly be ascribed to a change in intracellular pH and difference in the pH optima between pyruvate formate‐lyase (PFL) and lactate dehydrogenase (LDH). At extracellular pH values of 7.0 and 5.5, the intracellular pH values of S. mutans NCIB 11723 were 7.5 and 6.6, respectively. The pH optima of PFL and LDH were 7.8 and 5.5‐6.3, respectively. The cells had also a larger amount of LDH during growth at pH 5.5 than at pH 7.0.
Serum antibody responses to Streptococcus mutans antigens in humans systemically infected with oral streptococci
Authors: Russell M. W. , Wu H‐Y , White P. L. , Kilian M. , Henrichsen J.
Published: December 2007

Sera from patients with subacute bacterial endocarditis (SBE) due to Streptococcus mutans or other oral streptococci and from normal subjects were assayed by enzyme‐linked immunosorbent assay for antibodies to defined S. mutans antigens. Antibodies of IgG and IgA isotypes to Ag I/II and Ag III were greatly elevated in S. mutans‐SBE sera, and the IgA antibodies in 3 sera included both polymeric and monomeric forms. Elevated IgM and IgG anti‐lipoteichoic acid and IgG and IgA anti‐serotype c polysaccharide antibodies were also found. The sera of 4 of 6 patients infected with other oral streptococci also displayed antibodies to S. mutans Ag I/II. Sera of 3 patients infected with Streptococcus mitis or Streptococcus orallis. but none of the s. mutans‐infected cases, showed elevated antibodies to human heart sarcolemma, and all SBE sera had elevated rheumatoid factor. These results suggest that the known surface protein antigens of S. mutans are immunodominant in humans, and are not likely to be heart cross‐reactive.
Avidity and titer of immunoglobulin G subclasses to Porphymmonas gingivalis in adult periodontitis patients
Authors: Lopatin D. E. , Blackburn E.
Published: December 2007

The relative avidity and titer of antibodies representing the 4 immunoglobulin G (IgG) subclasses (IgGl‐4) reactive with Porphyromonas gingivalis, P. gingivalis‐lipopolysaccharide(‐LPS), streptokinase (SK) and tetanus toxoid (TT) in the sera of patients having adult periodontitis and of healthy controls were measured. Patient antibody titers to P. gingivalis and P. gingivalis‐LPS were found to be significantly elevated for IgG, IgGl (no P. gingivalis‐LPS antibodies) and IgG2. The predominant antibody response to P. gingivalis and P. gingivalis‐LPS occurred in the IgG2 subclass. When the relative avidity of the antibodies to P. gingivalis and P. gingivalis‐LPS were examined, no significant differences between control and patient sera could be identified. However, anti‐P. gingivalis and P. gingivalis‐LPS antibodies were found to possess significantly lower relative avidity than either SK or TT antibodies. The IgGl subclass antibodies to P. gingivalis, SK and TT all appeared to be of high relative avidity. In contrast, anti‐P. gingivalis and P. gingivalis‐LPS of the IgG2 subclass were of significantly lower relative avidity. Since the predominant humoral response to P. gingivalis occurs in the IgG2 subclass, the low relative avidity of these antibodies predominates in measurements of whole serum activity.
Immunosuppressive effect induced by Actinobacillus actinomycetemcomitans: effect on immunoglobulin production and lymphokine synthesis
Authors: Kurita‐Ochiai T. , Ochiai K. , Ikeda T.
Published: December 2007

The soluble sonicated extract (SE) from Actinobacillus actinomycetemcomitans inhibited primary T cell‐dependent antibody responses in vivo. The production of IgG and IgM to sheep red blood cells (SRBC) was depressed when mice were treated with high concentrations of SE plus SRBC. Preinjection of SE 3 days prior to SRBC completely inhibited IgG production. SE plus SRBC‐primed mice showed markedly depressed CD4/CD8 ratios relative to phosphate‐buffered saline plus SRBC‐ or SRBC‐immunized mice. SE‐sensilized mice showed low blastogenic activity to concanavalin A (Con A) depending on sensitized periods induced by SE. This inhibitory mechanism was, in part, clarified by a suppression of IL‐2 synthesis, IL‐2 receptor expression and IL‐6 secretion by the splenic T cells stimulated with Con A. These results support the hypothesis that the severe infection of A. actinomycetemcomitans suppresses the immune response by affecting CD4/CD8 ratios, followed by lymphokine production and finally antibody responses.
Identity of amino acid sequences of superoxide dismutase purified from both anaerobically maintained and aerated Porphyromonas gingivalis
Authors: Amano A. , Shizukuishi S. , Tsunemitsu A. , Tsunasawa S.
Published: December 2007

Superoxide dismutase (SOD) from anaerobically maintained Porphyromonas gingivalis (anaero‐SOD) has the characteristic of Fe‐SOD, whereas SOD from aerated cells (aero‐SOD) has that of Mn‐SOD. However, both types of apoSOD can bind either Fe or Mn. To elucidate the structure relationship between anaero‐ and aero‐SOD, we examined the amino acid sequence of aero‐SOD by direct protein analysis. The amino acid sequence of aero‐SOD was shown to be identical with that of anaero‐SOD determined previously. Our findings support the hypothesis that cambialistic SOD is formed from a single apoprotein in bacterial cells.
Rapid identification of Actinobacillus actinomycetemcomitans based on analysis of 23S ribosomal RNA
Authors: Preus H. R. , Sunday G. J. , Haraszthy V. I. , Zambon J. J.
Published: December 2007

Actinobacillus actinomycetemcomitans is a key microorganism in the pathogenesis of several different forms of periodontal diseases. Identification of this bacterium from clinical specimens may often be complicated by the fact that the colony morphology on TSBV selective medium closely resembles that of Haemophilus aphrophilus and a key differentiating characteristic, catalase reaction, may be variable. Recent genetic studies have shown that the 23S ribosomal RNA molecule is split into two smaller forms in A. actinomycetemcomitans, but is intact in H. aphrophilus. Based on this finding, we describe a new, rapid method for identifying A. actinomycetemcomitans in which single colonies isolated from culture on TSBV agar in 5% CO2 in air are lysed, electrophoresed on 1.5% submarine agarose gels and visualized by staining with ethidium bromide. Using this assay, A. actinomycetemcomitans can be easily distinguished from morphologically similar colonies such as H. aphrophilus strains by differences in 23S rRNA within 2h.