摘要:

Concanavalin A and fucose-binding protein, lectins with a high specificity for binding to D-mannose or D-glucose and L-fucose, respectively, have been found to reversibly bind and inactivate the factor or factors in saliva that are responsible for inducing the aggregation of Streptococcus mutans. The sugars for which the lectins are specific can block and reverse the binding, suggesting that the lectins are binding to specific sugar residues in the carbohydrate portion of the aggregating factor molecule.

ISSN:0008-6568    

DOI:10.1159/000260493

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

This study was undertaken to evaluate variations in the adsorption of acidic proline-rich proteins to hydroxyapatite seen in different types of saliva. The presence of other proteins in saliva significantly decreased the adsorption of the acidic proline-rich proteins. Adsorption to hydroxyapatite of varying concentrations of two of these proteins, A and C revealed that differences in concentration of acidic proline-rich proteins could at least partly explain the previously observed variations in adsorption. The amount of adsorbed protein decreased with increased concentration of inorganic phosphate. pH and physiological variations in ionic strength had a small effect on the adsorption of proteins A and C.

ISSN:0008-6568    

DOI:10.1159/000260494

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Two lactate dehydrogenase (EC 1.1.1.27) species were separated by agarose A 0.5 M molecular exclusion column chromatography from cell-free extracts obtained from Leptotrichia buccalis. Both lactate dehydrogenases were under negative control by the nucleoside-5’-triphosphate ATP, but the kinetic responses of the respective lactate dehydrogenase species to ATP were separate and distinct. The higher molecular weight lactate dehydrogenase (LDH1) showed a negative hyperbolic kinetic response to ATP, and Dixon plots of the ATP saturation data gave a Ki for ATP of 1.8 M. In contrast, the activity of the lower molecular weight lactate dehydrogenase (LDH2) was a negative sigmoidal function of the ATP concentration and had an [M]0.5V value for ATP of 2.5 M. A Hill coefficient (n) of 1.95 was obtained from Hill plots of the ATP saturation data for LDH2 which indicated multiple ATP binding sites on the enzyme with some degree of cooperation interaction between the

ISSN:0008-6568    

DOI:10.1159/000260495

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Two approximal plaque samples were collected from each member of 32 families. Streptococcus mutans strains obtained from the samples were then characterized by bacteriocin typing. Only one S. mutans type was found in 15 (∼ 50%) of the families. In 10 of these, all members were infected with a single common type and in the remaining 5 families, all but 1 or 2 subjects harboured the organism. More than one S. mutans type was found in 12 (∼ 40%) of families; no individual harboured more than one type and usually no more than 1 member was S. mutans-free. In 4 of these families, maternal transfer was indicated, and in another 3, paternal transfer seemed likely; in 1, neither parent seemed to be the source of infection and in the remaining 4, the situation was not clear-cut. Overall, in 28 (88%) of the families, a common S. mutans type was shared by at least 2 members, 1 of them a parent. Thus, intrafamilial transmission of some strains of S. mutans can occur; the source of infection may vary from family to family and it was suggested that further investigation into the vehicle(s) responsible for indirect salivary transfer of the organism seems warran

ISSN:0008-6568    

DOI:10.1159/000260496

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The effect of medium pH on fluoride resistance was studied using a stable, fluoride-resistant (FR) mutant of Streptococcus mutans 6715. When the mutant was grown in 750 ppm F (lethal for the wild type) and the initial pH was 7.8, significant growth occurred and the associated terminal pH was about 6.0. Growth was enhanced by graded reductions in the medium fluoride concentration and, in the absence of fluoride, growth was comparable to that of the wild type. This enhanced growth was associated with proportionate reductions in medium pH. When the initial medium pH was reduced to 6.1, growth of the wild type in fluoride-free medium was normal but that of the FR mutant in 750 ppm F was nil. Moreover, growth of the mutant at fluoride levels below 750 ppm was always reduced compared to the growth obtained when the initial pH was 7.8. With high fluoride levels, increasing the medium pH by back titration enhanced growth of the FR mutant. The results suggest that fluoride resistance is a function of the medium HF concentration.

ISSN:0008-6568    

DOI:10.1159/000260497

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

A method differentiating the critical level of Streptococcus mutans in whole saliva was developed. The procedure is as follows: 100 μl whole saliva is inoculated into 2 ml of MSB broth, the test tube is set tilted at a 60° angle and incubated aerobically at 37 °C for 24 h. The degree of adherence is then scored. When the adherence score is + + +, S. mutans may be assumed to be present at a level higher than 105/ml of whole saliva. On the other hand, if adherence is scored – or + S. mutans is present at a level lower than 104/ml of whole saliva. The method is useful for handling many samples in preventive practice and epidemiological studies, because of its simpli

ISSN:0008-6568    

DOI:10.1159/000260498

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

A toothpaste containing sodium fluoride and enzymes activating the anti-glycolytic lactoperoxidase-thiocyanate system was without inhibitory effects in 3 independent rat caries studies on formation of plaque, and smooth surface and fissure caries lesions when compared with a corresponding topical fluoride treatment. In contrast, topical hydrogen peroxide, mutanases, chlorhexidine and various fluoride dentifrices inhibited caries incidence significantly.

ISSN:0008-6568    

DOI:10.1159/000260499

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Fermenting sucrose, glucose and a simulated baby milk containing sugar and corn syrup produced lesions in enamel in vitro in an artificial mouth (the Orofax) which were significantly deeper than those produced by corn syrup, homemade yogurt, starch and lactose.

ISSN:0008-6568    

DOI:10.1159/000260500

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Substances frequently used in caries prevention have been studied with regard to their influence on the occurrence and rate of lesion repair. Single and periodical addition of fluorides and diphosphonates were compared in short, and long-term experiments. Diphosphonates, which are now used as anticalculus agents in tooth pastes, have an inhibitory effect on remineralization. Therefore, the use of diphosphonate-containing toothpastes should be dissuaded for children. Multiple application of low concentrations of fluorides are preferable to single high concentration treatments. In the latter case a rapidly formed, very insoluble precipitate in the surface layer pores prevents complete lesion repair.

ISSN:0008-6568    

DOI:10.1159/000260501

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The distribution of magnesium has been determined in the enamel of permanent human teeth. The concentrations increased from the surface towards the interior. The gradients were not smooth, pockets of relatively high magnesium concentration frequently occurred around the dentinal cornua and in the region of fissures. The distribution patterns obtained suggested a correlation between magnesium concentration and low density enamel and possibly between magnesium and protein concentration.

ISSN:0008-6568    

DOI:10.1159/000260502

出版商:S. Karger AG    

年代:1981

数据来源: Karger