RESUMEN
NO plays diverse roles in physiological and pathological processes, occasionally resulting in opposing effects, particularly in cells subjected to oxidative stress. NO mostly protects eukaryotes against oxidative injury, but was demonstrated to kill prokaryotes synergistically with H2O2. This could be a promising therapeutic avenue. However, recent conflicting findings were reported describing dramatic protective activity of NO. The previous studies of NO effects on prokaryotes applied a transient oxidative stress while arbitrarily checking the residual bacterial viability after 30 or 60min and ignoring the process kinetics. If NO-induced synergy and the oxidative stress are time-dependent, the elucidation of the cell killing kinetics is essential, particularly for survival curves exhibiting a "shoulder" sometimes reflecting sublethal damage as in the linear-quadratic survival models. We studied the kinetics of NO synergic effects on H2O2-induced killing of microbial pathogens. A synergic pro-oxidative activity toward gram-negative and gram-positive cells is demonstrated even at sub-µM/min flux of NO. For certain strains, the synergic effect progressively increased with the duration of cell exposure, and the linear-quadratic survival model best fit the observed survival data. In contrast to the failure of SOD to affect the bactericidal process, nitroxide SOD mimics abrogated the pro-oxidative synergy of NO/H2O2. These cell-permeative antioxidants, which hardly react with diamagnetic species and react neither with NO nor with H2O2, can detoxify redox-active transition metals and catalytically remove intracellular superoxide and nitrogen-derived reactive species such as (â¢)NO2 or peroxynitrite. The possible mechanism underlying the bactericidal NO synergy under oxidative stress and the potential therapeutic gain are discussed.
Asunto(s)
Antibacterianos/farmacología , Peróxido de Hidrógeno/farmacología , Modelos Estadísticos , Óxido Nítrico/farmacología , Oxidantes/farmacología , Actinomyces viscosus/efectos de los fármacos , Actinomyces viscosus/crecimiento & desarrollo , Actinomyces viscosus/metabolismo , Aggregatibacter actinomycetemcomitans/efectos de los fármacos , Aggregatibacter actinomycetemcomitans/crecimiento & desarrollo , Aggregatibacter actinomycetemcomitans/metabolismo , Óxidos N-Cíclicos/farmacología , Sinergismo Farmacológico , Escherichia coli/efectos de los fármacos , Escherichia coli/crecimiento & desarrollo , Escherichia coli/metabolismo , Viabilidad Microbiana/efectos de los fármacos , Nitroprusiato/farmacología , Streptococcus/efectos de los fármacos , Streptococcus/crecimiento & desarrollo , Streptococcus/metabolismo , Superóxido Dismutasa/farmacologíaRESUMEN
OBJECTIVE: To assess the effects of different natural medicines on the growth and acid production of Actinomyces viscosus, thus making preparations for screening an effective agent to mediate the balance of oral microflora. METHODS: Actinomyces viscosus ATCC 19246 was chosen as the experimental bacteria. 11 kinds of traditional Chinese medicine, such as Rhizoma Ligustici Chuanxiong, Sargentodoxa Cuneata and Galla Chinensis were extracted by means of maceration, percolation and reflux extraction. First, the values of MIC of various extracts were measured. Second, the experimental medium containing various extracts was prepared. The concentration of the extracts was lower than the MIC of the medicine, and the initial pH of the medium was 7.4. Then Actinomyces viscosus was cultured in the medium for 48 h, and finally the rest pH was measured. RESULTS: When the concentration of the medicines was lower than or equal to 8.000 mg/ml, it was found that all kinds of medicine except Radix Notoginseng can inhibit the growth of Actinomyces viscosus effectively, especially Polistes mandarinus and Semen Arecae. Tea polyphenols, Radix Notoginseng, Radix et Rhizoma Rhei, Polistes mandarinus and Sargentodoxa cuneata can inhibit the acid production of Actinomyces viscosus effectively, but Radix Scutellariae, Rhizoma Ligustici Chuanxiong, Semen Arecae, Radix Angelicae Dahuricae, Galla Chinensis and Catechu have no preliminary effect on it. CONCLUSION: Tea polyphenols, Radix et Rhizoma Rhei, Polistes mandarinus and Sargentodoxa cuneata can inhibit the growth and the acid production of Actinomyces viscosus effectively.
Asunto(s)
Actinomyces viscosus/efectos de los fármacos , Cariostáticos/farmacología , Medicamentos Herbarios Chinos/farmacología , Flavonoides , Ácidos/análisis , Actinomyces viscosus/metabolismo , Fenoles/farmacología , Polímeros/farmacología , PolifenolesRESUMEN
Adhesion to adsorbed pellicles and interspecies co-adhesion to form plaque biofilms involve selective interactions of bacterial adhesins with specific receptors. Our laboratory has devised in vitro assays for co-adhesion between Actinomyces naeslundii and Streptococcus oralis or Porphyromonas gingivalis on saliva-coated mineral and hexadecane droplet substrata. P. gingivalis structures significant for co-adhesion with A. naeslundii include surface vesicles and fimbriae. A family of arginine-specific cysteine proteinases in vesicles may be involved in adherence to bacteria, to host cells, and to matrix proteins. New research from several laboratories has found that such proteinases are processed from genes encoding polyproteins containing both proteinase and hemagglutinin domains. In addition to enzyme-substrate recognition, bacterial adhesion is often determined by specific protein-peptide and lectincarbohydrate recognition. A. naeslundii--salivary prolinerich protein, S. gordonii--salivary alpha-amylase, and Treponema denticola--matrix protein recognition are examples of the former. Co-adhesion of A. naeslundii and S. oralis is an example of the latter. Lactose can selectively desorb A. naeslundii cells from mixed biofilms with S. oralis, a demonstration of the significance of specificity. Although non-specific forces are probably secondary to stereochemical fit in determining the selective range of surfaces that bacteria have evolved to recognize and bind, they probably help stabilize non-covalent bonds within aligned, complementary domains.
Asunto(s)
Actinomyces viscosus/fisiología , Adhesión Bacteriana/fisiología , Proteínas Bacterianas/fisiología , Biopelículas , Placa Dental/microbiología , Porphyromonas gingivalis/fisiología , Actinomyces viscosus/genética , Actinomyces viscosus/metabolismo , Adhesinas Bacterianas/química , Adhesinas Bacterianas/fisiología , Proteínas Bacterianas/química , Biopelículas/crecimiento & desarrollo , Cisteína Endopeptidasas/metabolismo , Ecosistema , Fimbrias Bacterianas/fisiología , Cisteína-Endopeptidasas Gingipaínas , Hemaglutininas/metabolismo , Humanos , Modelos Biológicos , Porphyromonas gingivalis/genética , Porphyromonas gingivalis/metabolismo , Streptococcus/fisiología , Especificidad por SustratoRESUMEN
Actinomyces amphiphile (AcA) is an amphipathic molecule produced by Actinomyces viscosus that exhibits several biological activities. The effect of AcA on the fluidity and permeability of the plasma membrane in human umbilical vein endothelial cells was analyzed by a spin label method with 5- and 16-stearic acid nitroxide labels (SAL). These labels help to visualize the fluidity at the shallow (5-SAL) and deep (16-SAL) portions of the lipid bilayer. Cells were incubated with and without AcA (control) at 37 degrees C for 6 hours, and membrane fluidity was periodically measured. Another spin label, 4-(N, N-dimethyl-N-hexadecyl) ammonium-2, 2, 6, 6-tetramethyl-piperidine-1-oxyliodine (CAT-16), was also used to assess the physical state of the cell surface. The order parameter of 5-SAL was significantly lower in the cells incubated with AcA than in control cells after the six-hour incubation. The motion parameter of 16-SAL was significantly lower in AcA-treated cells than in controls after 4 and 6 hours of incubation. These findings indicated that the AcA increased the fluidity. There were no significant differences between the AcA-treated and control cells incubated for only 2 hours. In addition, there were no differences in CAT-16 measurements between AcA-treated and control cells. The release of endoplasmic lactate dehydrogenase (LDH) into the medium tended to increase in the AcA-treated vs. the control cells. LDH release increased in both a dose- and time-dependent manner, indicating that AcA increased the permeability of plasma membranes. These findings suggest that AcA alters the biophysical properties of the plasma membranes of endothelial cells, affecting membrane function.
Asunto(s)
Actinomyces viscosus/química , Endotelio Vascular/efectos de los fármacos , Fluidez de la Membrana/efectos de los fármacos , Actinomyces viscosus/metabolismo , Actinomyces viscosus/patogenicidad , Adulto , Permeabilidad de la Membrana Celular/efectos de los fármacos , Separación Celular , Relación Dosis-Respuesta a Droga , Espectroscopía de Resonancia por Spin del Electrón/métodos , Espectroscopía de Resonancia por Spin del Electrón/estadística & datos numéricos , Endotelio Vascular/citología , Endotelio Vascular/enzimología , Femenino , Humanos , L-Lactato Deshidrogenasa/análisis , L-Lactato Deshidrogenasa/efectos de los fármacos , Marcadores de Spin , Tensoactivos/farmacología , Factores de Tiempo , Venas Umbilicales/citología , Venas Umbilicales/efectos de los fármacos , Venas Umbilicales/enzimologíaRESUMEN
Earlier studies have demonstrated that pure cultures of oral streptococci produce hydrogen peroxide but none has found any free peroxide in dental plaque or salivary sediment despite streptococci being major components of their mixed bacterial populations. The absence of peroxide in plaque and sediment could be due to the dominance of its destruction over its formation by bacterial constituents. To identify which of the oral bacteria might be involved in such a possibility, pure cultures of 27 different oral bacteria were surveyed (as well as dental plaque and sediment) for their peroxide-forming and peroxide-removing capabilities. Peroxide production was measured for each of the pure cultures by incubation with glucose at low and high substrate concentrations (2.8 and 28.0 mM) for 4 h and with the pH kept at 7.0 by a pH-stat. Removal of hydrogen peroxide was assessed in similar experiments where peroxide at 0, 29.4, 147.2 or 294.4 mM [0, 0.1, 0.5 and 1% (w/v)] replaced the glucose. Hydrogen peroxide formation was seen with only three of the bacteria tested, Streptococcus sanguis I and II (sanguis and oralis), and Strep. mitior (mitis biotype I); levels of hydrogen peroxide between 2.2 and 9.8 mM were produced when these micro-organisms were grown aerobically and 1.1 and 3.9 mM when grown anaerobically. Earlier reports indicate that such levels were usually sufficient to inhibit the growth of many plaque bacteria. The amounts formed were similar at the two glucose levels tested, suggesting that maximum peroxide production is reached at low glucose concentration. None of the three peroxide-producing organisms was able to utilize hydrogen peroxide but five of the other 24 tested, Neisseria sicca, Haemophilus segnis, H. parainfluenzae, Actinomyces viscosus and Staphylococcus epidermidis, could readily do so, as could the mixed bacteria in salivary sediment and dental plaque, both of which contain relatively high numbers of these peroxide-utilizing micro-organisms. The ability of the bacteria in plaque and sediment to degrade hydrogen peroxide was considerable and extremely rapid; peroxide removal and usually complete within the first 15 min of the incubation even when its initial level was as high as 294.4 mM. This almost overwhelming ability to remove peroxide was confirmed when peroxide-producing and -using cultures were mixed and when each of eight salivary sediments was incubated with glucose and with peroxide at concentrations up to 294.4 mM. In the glucose incubations, no hydrogen peroxide was observed, indicating dominance of microbial peroxide removers over hydrogen peroxide producers.(ABSTRACT TRUNCATED AT 400 WORDS)
Asunto(s)
Bacterias/metabolismo , Placa Dental/metabolismo , Placa Dental/microbiología , Glucólisis , Peróxido de Hidrógeno/metabolismo , Actinomyces viscosus/metabolismo , Antibiosis , Galactosa/metabolismo , Glucosa/metabolismo , Haemophilus/metabolismo , Humanos , Concentración de Iones de Hidrógeno , Lactatos/metabolismo , Boca/microbiología , Neisseria/metabolismo , Saliva/metabolismo , Saliva/microbiología , Streptococcus/metabolismoRESUMEN
The initial steps of sorbitol catabolism were studied in 4 strains of Actinomyces naeslundii and Actinomyces viscosus that had been isolated from human dental plaque. Cell-free extracts were prepared from cells grown in the presence of either sorbitol, xylitol or glucose. The extracts from all strains grown on sorbitol had nicotinamide adenine dinucleotide-linked dehydrogenase activities for sorbitol and xylitol and reduced nicotinamide adenine dinucleotide-linked reductase activities for fructose and xylulose. Two of the strains also exhibited these activities when grown in the presence of xylitol, and all glucose-grown cells lacked them. The results indicate that sorbitol metabolism in oral actinomyces involve oxidation of sorbitol to fructose by an inducible enzyme, nicotinamide adenine dinucleotide-linked sorbitol dehydrogenase. This step is followed by the phosphorylation of fructose with guanosine triphosphate as a main phosphoryl donor. Thus, the initial catabolic pathway of sorbitol in A. naeslundii and A. viscosus is different from those described for other oral bacteria.
Asunto(s)
Actinomyces/metabolismo , Sorbitol/metabolismo , Actinomyces viscosus/metabolismo , Inducción Enzimática , Fructosafosfatos/metabolismo , Hexoquinasa/metabolismo , L-Iditol 2-Deshidrogenasa/metabolismo , NAD/metabolismo , NADH NADPH Oxidorreductasas/metabolismo , Oxidorreductasas/metabolismoRESUMEN
The sorbitol fermentation by Actinomyces viscosus and Actinomyces naeslundii was studied with washed sorbitol-grown cells. The fermentation was followed by titration of acids produced at pH 7.0 under anaerobic conditions. Metabolic end-products and intracellular levels of NAD, NADH and glycolytic intermediates during the fermentation were also analyzed. Cell extracts were examined for certain enzyme activities. Bicarbonate was required for acid production from sorbitol and from a mixture of glucose and sorbitol. Malate and fumarate could also support the acid production of A. viscosus. The main end-products were succinate and lactate but not ethanol. Cell extracts showed no activities of alcohol and aldehyde dehydrogenases, but they had activities of malate dehydrogenase and fumarate reductase. In the absence of bicarbonate, malate or fumarate, the intracellular NADH/NAD ratio increased and the levels of 3- and 2-phosphoglycerate and phosphoenolpyruvate decreased. The results indicate that oral sorbitol-fermenting actinomyces lack the ethanol pathway that can contribute to NADH oxidation. To maintain intracellular redox balance during anaerobic sorbitol fermentation, these bacteria can oxidize surplus NADH through a succinate pathway.
Asunto(s)
Actinomyces/metabolismo , Sorbitol/metabolismo , Succinatos/metabolismo , Actinomyces/efectos de los fármacos , Actinomyces/enzimología , Actinomyces viscosus/efectos de los fármacos , Actinomyces viscosus/enzimología , Actinomyces viscosus/metabolismo , Placa Dental/microbiología , Fermentación/efectos de los fármacos , Fermentación/fisiología , Fumaratos/metabolismo , Fumaratos/farmacología , Glucosa/metabolismo , Glucólisis , Humanos , Lactatos/biosíntesis , Maleatos/metabolismo , Maleatos/farmacología , NAD/análisis , NAD/metabolismo , Bicarbonato de Sodio/química , Bicarbonato de Sodio/farmacologíaRESUMEN
Actinomyces viscosus T14V, a Gram-positive bacterium found in the oral cavity, was found to be insensitive to glucose-mediated catabolite repression. Basal levels of beta-galactosidase (18-26 U) were observed at all phases of growth regardless of the culture conditions. Further, beta-galactosidase could not be induced with lactose, or with a known inducer of the enzyme, isopropyl-beta-D-thiogalactoside, or with dibutyryl cAMP. Glucose, on the other hand, stimulated cAMP accumulation in a concentration-dependent manner. Fructose and sucrose mimicked the effects of glucose on cAMP accumulation, whereas galactose, mannose and maltose had lesser stimulatory effects. Other carbon sources, i.e., lactose, alpha-methylglucoside, ribose, xylose and succinate were without effect. Glucose and alpha-methylglucoside were found to stimulate cAMP accumulation in toluene-permeabilized cells, in the presence of the phosphodiesterase inhibitor, theophylline. Glucose did not stimulate cAMP levels in other Gram-positive bacteria including Streptococcus mutans, S. sanguis and S. salivarius but did cause cAMP accumulation in other strains of A. viscosus. The results suggest that glucose effects on cAMP metabolism are independent of the induction of beta-galactosidase as presently defined for Escherichia coli, and that the effects appear to be selective to the A. viscosus bacteria. The results also suggest that glucose stimulates cAMP accumulation via activation of adenylate cyclase.
Asunto(s)
Actinomyces viscosus/efectos de los fármacos , AMP Cíclico/metabolismo , Glucosa/farmacología , Boca/microbiología , Actinomyces viscosus/metabolismo , Adenilil Ciclasas/metabolismo , Fructosa/farmacología , Humanos , Lactosa/farmacología , beta-Galactosidasa/metabolismoRESUMEN
Actinomyces viscosus strains, freshly isolated from root surface caries lesions and intact root surfaces, were studied for their glycogen synthetic and degradative activities at pH 4.5, 5.0, and 7.0 in a pH-stat. At all three pH levels, root caries origin of A. viscosus synthesized up to three times as much glycogen compared to non-root caries origin. Since root caries origin of A. viscosus strains initially synthesized large amounts of glycogen, a longer period of time was required to deplete this polymer, resulting in an extended period of acid production, even at pH 4.5 and pH 5.0. This study suggests that the ability of A. viscosus of root caries origin to synthesize large quantities of glycogen and subsequently degrade this stored polymer slowly with acid production, at acidic pH levels, may play an important role in the root caries process.
Asunto(s)
Actinomyces viscosus/metabolismo , Glucógeno/metabolismo , Caries Radicular/microbiología , Raíz del Diente/microbiología , Ácidos/metabolismo , Actinomyces viscosus/genética , ADN Bacteriano/análisis , Placa Dental/microbiología , Glucosa/metabolismo , Glucógeno/análisis , Glucógeno/biosíntesis , Glucólisis , Humanos , Concentración de Iones de Hidrógeno , Factores de TiempoRESUMEN
Recent studies have provided evidence for human salivary proline-rich proteins (PRPs) serving as potential receptors in the acquired pellicle for Actinomyces viscosus type 1 fimbriae. We report here the isolation of mutants derived from A. viscosus T14V-J1 which are defective in binding to PRPs partially purified from parotid gland saliva. Mutagenesis with ethyl methanesulfonate preceded enrichment for cells nonreactive with PRPs by successive adsorptions with PRP-treated latex beads. Screening was accomplished by random selection of 250 isolated colonies from each of four enrichment cycles and reaction with PRP-treated latex beads in microtiter plates. Two mutants of independent origin were examined for adherence to hydroxyapatite treated with either PRPs, proline-rich glycoproteins, deglycosylated proline-rich glycoproteins, or whole saliva. Additional surface properties that were examined included agglutination with polyclonal antisera to type 1 and type 2 fimbriae, agglutination by a monoclonal antibody to type 1 fimbriae that inhibits adherence of the parent strain to saliva-treated hydroxyapatite, the ability to bind monoclonal antibody to the type 1 fimbrial subunit, and lactose-reversible coaggregation with Streptococcus sanguis 34. Both mutants exhibited reduced binding to hydroxyapatite treated with whole saliva or salivary protein preparations but were still capable of reaction with antiserum to type 1 and type 2 fimbriae. In addition, these mutants possessed the ability to bind monoclonal antibody to the type 1 fimbrial subunit in amounts comparable to the amount bound by the parent strain but were not agglutinated by the adherence-inhibiting monoclonal antibody. When considered with previously published data, these results suggest that an adhesive molecule is probably associated with type 1 fimbriae and allows for the interaction of A. viscosus with constituents in the salivary pellicle.
Asunto(s)
Actinomyces viscosus/metabolismo , Péptidos/metabolismo , Proteínas y Péptidos Salivales/metabolismo , Actinomyces viscosus/aislamiento & purificación , Adsorción , Anticuerpos Monoclonales/inmunología , Adhesión Bacteriana , Película Dental , Fimbrias Bacterianas/metabolismo , Humanos , Mutación , Dominios Proteicos Ricos en ProlinaRESUMEN
A replica-plate assay was used to screen for the interaction of salivary molecules with dental plaque bacteria. Bacterial colonies cultured from supragingival plaque on sheep-blood (SB) agar were replica-plated onto nitrocellulose membranes overlaying SB or mitis-salivarius agar. Membranes with attached colonies were removed and incubated with 125I-amylase or 125I-proline-rich glycoprotein (PRG). Positive interactions were detected by autoradiography. Only strains of Streptococcus gordonii and Actinomyces viscosus bound amylase, and strains of A. viscosus bound PRG. The results suggest that amylase and PRG bind to selected species of aerobic dental plaque bacteria.
Asunto(s)
Actinomyces/metabolismo , Amilasas/metabolismo , Técnicas Bacteriológicas , Placa Dental/microbiología , Péptidos/metabolismo , Proteínas y Péptidos Salivales/metabolismo , Streptococcus/metabolismo , Actinomyces viscosus/metabolismo , Adulto , Autorradiografía , Colodión , Humanos , Masculino , Membranas Artificiales , Dominios Proteicos Ricos en Prolina , Unión Proteica , Técnicas de Réplica , Saliva/enzimología , Saliva/microbiología , Saliva/fisiologíaRESUMEN
Erythritol is a sugar alcohol produced by Aureobasidium sp. from glucose. It is 75-80% as sweet as sucrose and is also nonhygroscopic. The aim of this study was to evaluate this sugar substitute from a cariological point of view. Erythritol was neither utilized as a substrate for the lactic acid production nor for plaque formation of mutans streptococci (serotypes a-h) and certain oral microorganisms. It was not utilized for water-insoluble glucan synthesis or cellular adherence by glucosyltransferase from Streptococcus mutans PS-14 (c) and Streptococcus sobrinus 6715 (g). Finally, a significantly lower caries score (3.1 +/- 0.5; mean +/- SEM) was observed in specific pathogen-free rats infected with S. sobrinus 6715 and fed with a diet containing 26% erythritol, as compared to control rats fed with a diet containing 26% sucrose (60.5 +/- 2.0). Also, rats provided a diet containing 56% erythritol chocolate (23.8% erythritol) and challenged with S. mutans PS-14 exhibited a significantly lower caries score (6.7 +/- 0.8) compared to the sucrose chocolate group (82.8 +/- 2.8). The main conclusion from this study is therefore that erythritol is a promising sugar substitute from a cariological point of view.
Asunto(s)
Cariostáticos/farmacología , Eritritol/farmacología , Edulcorantes/farmacología , Actinomyces/efectos de los fármacos , Actinomyces/metabolismo , Actinomyces viscosus/efectos de los fármacos , Actinomyces viscosus/metabolismo , Animales , Adhesión Bacteriana , Caries Dental/etiología , Placa Dental/microbiología , Glucosiltransferasas/metabolismo , Técnicas In Vitro , Lactatos/biosíntesis , Ácido Láctico , Lactobacillus acidophilus/efectos de los fármacos , Lactobacillus acidophilus/metabolismo , Lacticaseibacillus casei/efectos de los fármacos , Lacticaseibacillus casei/metabolismo , Ratas , Ratas Sprague-Dawley , Organismos Libres de Patógenos Específicos , Streptococcus/efectos de los fármacos , Streptococcus/metabolismo , Streptococcus mutans/clasificación , Streptococcus mutans/efectos de los fármacos , Streptococcus mutans/enzimología , Streptococcus mutans/metabolismo , Streptococcus sanguis/efectos de los fármacos , Streptococcus sanguis/metabolismo , Streptococcus sobrinus/efectos de los fármacos , Streptococcus sobrinus/metabolismoRESUMEN
Each of five monoclonal antibodies (mAbs) prepared against the type 1 fimbriae of Actinomyces viscosus T14V reacted with a 54 kDa cloned protein previously identified as a fimbrial subunit. This purified protein completely inhibited the reaction of a specific anti-type-1-fimbria rabbit antibody with A. viscosus whole cells. Maximum values for the number of antibody molecules bound per bacterial cell ranged from 7 x 10(3) to 1.2 x 10(4) for the different 125I-labelled mAbs and was approximately 7 x 10(4) for 125I-labelled rabbit IgG or Fab against either type 1 fimbriae or the 54 kDa cloned protein. Although the different mAbs, either individually or as a mixture, failed to inhibit the type-1-fimbria-mediated adherence of A. viscosus T14V to saliva-treated hydroxyapatite, each rabbit antibody gave 50% inhibition of adherence when approximately 5 x 10(4) molecules of IgG were bound per cell. However, binding of each corresponding rabbit Fab had no significant effect on bacterial attachment unless much higher concentrations were used. These findings suggest that antibodies directed solely against the 54 kDa fimbrial subunit do not react with the putative receptor binding sites of A. viscosus T14V type 1 fimbriae. Instead, inhibition of attachment by the polyclonal antibodies may depend on an indirect effect of antibody binding that prevents the fimbria-receptor interaction.
Asunto(s)
Actinomyces viscosus/metabolismo , Adhesión Bacteriana/fisiología , Proteínas Bacterianas/inmunología , Fimbrias Bacterianas/inmunología , Actinomyces viscosus/inmunología , Pruebas de Aglutinación , Anticuerpos Monoclonales/metabolismo , Proteínas Bacterianas/metabolismo , Sitios de Unión/fisiología , Durapatita , Electroforesis en Gel de Poliacrilamida , Fimbrias Bacterianas/química , Fimbrias Bacterianas/metabolismo , Hidroxiapatitas/metabolismo , Fragmentos Fab de Inmunoglobulinas/metabolismo , Inmunoglobulina G/metabolismo , Microscopía Electrónica , Saliva/metabolismoRESUMEN
Erythritol is a sugar alcohol which is obtained through a cultivation of glucose and Aureobasidium sp. The sugar is about 70-80% as sweet as sucrose and is also non-hygroscopic. The effect of erythritol on cariogenicities of mutans streptococci (serotype a-h) and certain oral microorganisms was studies. Erythritol was not utilized as a substrate for the growth, lactic acid production and plaque formation of mutans streptococci (serotype a-h). It did not serve as a substrate for cellular aggregation of mutants streptococci (serotype d, g, h) and was not utilized water-insoluble glucan synthesis and cellular adherence by glucosyltransferase from S. mutans PS-14 (c) or S. sorbrinus 6715 (g). Erythritol was not also utilized for the growth and lactic acid production of certain oral microorganisms although some growth was seen with Actinomyces viscosus. SPF SD rats infected with S. sobrinus 6715 were fed a diet containing 26% erythritol or 26% sucrose for 53 days. A significantly (p less than 0.01) lower caries score (mean +/- SE; 3.1 +/- 0.5) was observed in the rat fed a diet containing erythritol than the control (60.5 +/- 2.0). The caries inhibition rate is 94.9%. Also, rats infected with S. mutans PS-14 were fed a diet containing 56% erythritol chocolate or 56% sucrose chocolate for 58 days. The mean total caries score of rats fed a diet containing 56% erythritol chocolate was 6.7 +/- 0.8, while the mean total caries score of rats fed a diet containing 56% sucrose chocolate was 82.8 +/- 2.8. The value between both groups was significant at 0.01 level, and the caries inhibition rate is 91.9%.