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Independence of water‐insoluble glucan synthesis and adherence of Streptococcus mutans to smooth surfaces
Author(s) -
Fukushima Kazuo,
Takada Kazuko,
Motoda Ryuichi,
Ikeda Tadashi
Publication year - 1982
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(82)81121-6
Subject(s) - bacteriology , dentistry , streptococcus mutans , medicine , biology , bacteria , genetics
Water-insoluble glucans (WIG) produced from sucrose by Streptococcus mutans glucosyltransferases (GTases) are of major importance in the adherence and colonization of the organisms on tooth surfaces and the subsequent development of dental caries [ 1,2]. In fact, mutants of S. mutans which lack the ability to synthesize WIG do not stick to glass surfaces and do not induce smoothsurface-caries formation in germ-free rats [3]. Although it has been suggested that active de novo WIG synthesis from sucrose is essential for cell adherence [4-61, the exact relationship between WIG synthesis and cell adherence, as well as these mechanisms, are still not elucidated. The adhesive WIG synthesis of S. mutans strain B-13 (serotype d) is caused by a cooperative action of 2 GTase components, GT-I and GT-S, which catalyze mainly the formation of 1,3-a-Dand 1,6-cy-D-glucosidie linkage, respectively [7,8]. at 37°C for 20h in defined medium M4 [9] with 0.5% glucose as a carbon source. The harvested cells were heated at 100°C for 20 min, washed twice with distilled water and lyophilized. GT-I and GT-S were purified from the culture fluids as in [6,7]. Homogeneity of both GTase components were confirmed by PAGE, SDS-PAGE and double immunodiffusion. In part, a 40% ethanol fraction [7] was used as a crude GTase preparation. Specific activities of the crude GTase, GT-I and GT-S, were 17.3, 25.5 and 56.4 IU/mg protein, respectively. The activity of GT-I was assayed turbidimetrically in the presence of 0.067% dextran TlO.