Sucrose-promoted accumulation of growing glucosyltransferase variants of Streptococcus gordonii on hydroxyapatite surfaces.
Streptococcus gordonii exhibits a phase variation involving expression of high (Spp+) or low (Spp-) glucosyltransferase activity. The related bacterial accumulation on hydroxyapatite (HA) and saliva-coated HA surfaces was examined and found to be significant. Spp+ cells growing anaerobically in a defined medium utilize about 30% of the glucose available from sucrose to make insoluble glucans. These glucans formed cohesive masses on HA beads, which contained 80 to 90% of the total bacteria. The bacterial polymer mass had a volume of about 40 microns3 and contained more than 5 x 10(10) viable cells per cm3. In the absence of sucrose, the beads were saturated by 1 x 10(8) to 2 x 10(8) Spp+ cells. Spp- bacteria, which make 30-fold less glucan than do Spp+ bacteria, did not accumulate on surfaces in numbers significantly above the saturation level of 1 x 10(8) to 2 x 10(8) cells in the presence or absence of sucrose. Insoluble glucan synthesized by Spp+ cells from sucrose also enabled these bacteria to accumulate on saliva-coated HA seven times more effectively than the Spp- cells and 10 times more effectively than the Spp+ cells grown in medium without sucrose.
Vickerman
M M
MM
Department of Microbiology, School of Medicine, University of Michigan, Ann Arbor 48109.
Clewell
D B
DB
Jones
G W
GW
D003470:Culture Media; D003911:Dextrans / Q000494:pharmacology; D017886:Durapatite; D005964:Glucosyltransferases / Q000032:analysis*; D006801:Humans; D006882:Hydroxyapatites / Q000494:pharmacology*; D008297:Male; D012463:Saliva / Q000502:physiology; D013291:Streptococcus / Q000201:enzymology / Q000254:growth & development*; D013395:Sucrose / Q000494:pharmacology*
D003470:Culture Media; D003911:Dextrans; D006882:Hydroxyapatites; D013395:Sucrose; D017886:Durapatite; D005964:Glucosyltransferases