Scanning Electron Microscope Studies of Dextranase-Treated Plaque Streptococci

Hoffman, Seymour; Tow, Herman D.; Cole, John S.

doi:10.1177/00220345730520032901

Cited by 16 publications

(6 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The effects of dextranase on the formation of artificial dental plaque by S. mutans strain 6715 (serotype d) have been reported by Hoffman et al (17). In their scanning electron microscopic studies, they described honeycombed demineralization patterns on the enamel surface just underneath the artificial plaque after incubation for 138 h. However, this type of demineralization pattern could not be observed in our experiment.…”

Section: Discussionsupporting

confidence: 49%

Effect of dextranase on the extracellular polysaccharide synthesis of Streptococcus mutans; chemical and scanning electron microscopy studies

Hamada¹,

Mizuno²,

Murayama³

et al. 1975

Infect Immun

View full text Add to dashboard Cite

A dextranase preparation (AD17) partially purified from a culture liquor of Spicaria violacea strain IFO 6120 significantly inhibited the formation of artificial dental plaque on a steel wire or on an extracted tooth surface. Changes in the surface morphology of Streptococcus mutans cells due to AD17 action were studied using scanning electron microscopy. S. mutans cells grown in 5% sucrose-containing broth were coated with sticky amorphous capsule-like material, whereas cells grown in sucrose in the presence of AD17 or in glucose instead of sucrose did not synthesize such capsular material. AD17 degraded commercially available dextrans of molecular weight 7 x 101 and 2 x 106 to liberate glucose and various oligosaccharides, including isomaltose. On the other hand, AD17 hydrolyzed the extracellular polysaccharides (mainly glucan in nature) of some strains of S. mutans to a limited degree. Only 15 to 36% of the total polysaccharides were hydrolyzed by AD17 with little release of isomaltose. Prolonged incubation of the polysaccharides from S. mutans with AD17 did not release additional reducing sugars, which indicates that AD17 did not contain a-1,3-glucanase activity. These results suggest that glucosidic linkages which are susceptible to AD17 may play an important role in the adherence of S. mutans cells to smooth surfaces.

show abstract

Section: Discussionsupporting

confidence: 49%

Effect of dextranase on the extracellular polysaccharide synthesis of Streptococcus mutans; chemical and scanning electron microscopy studies

Hamada¹,

Mizuno²,

Murayama³

et al. 1975

Infect Immun

View full text Add to dashboard Cite

show abstract

“…In the prevention of dental caries, dextranase is one of the effective agents which digest the 1,6-a-glucoside bond of water-insoluble glucan on the tooth surface, and dextranase significantly inhibits the production of water-insoluble glucan and the adherence of mutans streptococci cells in vitro (8,11,15,23,28). However, rigorous use of mouth rinses that contain highly concentrated dextranase is necessary for the dispersion and prevention of bacterial plaques in vivo (2,4,7,12,17,24).…”

Section: Discussionmentioning

confidence: 99%

“…The water-insoluble glucan is a 1,6-a-linked polymer with a high proportion of 1,3-a-linked glucosyl residues (5,10,19). Dextranase is an enzyme which hydrolyzes the 1,6-a-glucosidic linkages of glucan and is known to repress the adherence of mutans streptococci to the tooth surface in vitro (8,11,15,23,25). This enzyme also retards plaque deposition on the tooth surface and thus inhibits dental caries in experimental animals (2,7,12).…”

mentioning

confidence: 99%

Expression and secretion of an Arthrobacter dextranase in the oral bacterium Streptococcus gordonii

et al. 1993

View full text Add to dashboard Cite

show abstract

“…This is consistent with the previous findings of others (5) on the partially disruptive effects of dextranases on preformed S. mutans plaque. Partial removal of cell-associated S. mutans dextrans by dextranase has been reported (17,29). The lack of water-insoluble levan production by the S. mutans strain 6715 (serological group d) levansucrase (EC 2.4.1.10) ( Table 1) indicates that the sucrose-utilizing extracellular polysaccharide-producing enzymes from this bacterium are different from those elaborated by S. mutans strain HS6 (serological group a).…”

Section: 'mentioning

confidence: 99%

Dextranases from oral bacteria: inhibition of water-insoluble glucan production and adherence to smooth surfaces by Streptococcus mutans

Schachtele¹,

Staat²,

Harlander³

1975

Infect Immun

113

View full text Add to dashboard Cite

The effect of dextranases (EC 3.2.1.11) from the oral isolates Actinomyces israelii and Bacteroides ochraceus on water-insoluble glucan production by the Streptococcus mutans dextransucrase (EC 2.4.1.5) and sucrose-dependent adherence to smooth glass surfaces by S. mutans was studied. Collection on membrane filters of water-insoluble polysaccharides synthesized from radioactive sucrose was used to demonstrate the marked sensitivity of insoluble glucan formation to the presence of dextranase. Concentrations of A. israelii dextranase as low as 0.002 U/ml inhibited insoluble glucan formation by 60%. Similar results were obtained with the B. ochraceus enzyme. An assay for sucrose-stimulated adherence of S. mutans to smooth surfaces involved attachment of radioactively labeled nongrowing cells to the bottom of glass scintillation vials. This facile and sensitive assay was utilized to demonstrate that sucrose-dependent adherence was affected by low levels of dextranase from either A. israelii or B. ochraceus. Enzyme at 0.005 U/ml reduced adherence of S. mutans by 80%. Treatment of S. mutans cells previously attached to glass with low concentrations of the dextranases resulted in removal of 50 to 60% of the bacteria. These results indicate that dextranase-producing oral bacteria may affect sucrose-dependent colonization of S. mutans on the tooth surface and offer a possible explanation for both the difficulties involved in implanting this bacterium into the human mouth and the limited intraoral transmission of S. mutans from one tooth surface to another. Recent studies in these laboratories (39) demonstrated that a significant proportion of the human dental plaque bacterial flora is capable of producing dextran-degrading enzymes. These bacteria were shown to be a heterogeneous mixture of cell types with varying morphological and biochemical properties. One representative isolate which produces an extracellular endohydrolytic dextranase activity has been identified as Actinomyces israelii (39; R. Staat and C.

show abstract

Scanning Electron Microscope Studies of Dextranase-Treated Plaque Streptococci

Abstract: The in vitro effects of dextranase on extracellular polysaccharide-producing streptococci grown on autoclaved enamel samples were evaluated by scanning electron microscopy. This enzyme was found to be highly effective in dispersing both strains of streptococci when compared with controls.

Cited by 16 publications

References 10 publications

Effect of dextranase on the extracellular polysaccharide synthesis of Streptococcus mutans; chemical and scanning electron microscopy studies

Effect of dextranase on the extracellular polysaccharide synthesis of Streptococcus mutans; chemical and scanning electron microscopy studies

Expression and secretion of an Arthrobacter dextranase in the oral bacterium Streptococcus gordonii

Dextranases from oral bacteria: inhibition of water-insoluble glucan production and adherence to smooth surfaces by Streptococcus mutans

Contact Info

Product

Resources

About