Streptococcus mutans strain JH1005 is a mutant that produces levels of bacteriocin activity three-fold-elevated than those produced by its parent, JH1001. A single infection regimen with JH1005 was found to result in persistent colonization of the teeth of all three adult subjects tested. This is a significant improvement over JH1001, which required multiple exposures in order to colonize the teeth of humans reliably. The levels of total cultivable bacteria and indigenous S. sanguis were not affected by JH1005 colonization. In two of the three subjects, total (indigenous plus JH1005) S. mutans levels were significantly decreased. The results provide additional support for the role of bacteriocin production as an ecological determinant in colonization by S. mutans. They also indicate that a practical regimen for infection by an effector strain might be achieved for use in the replacement therapy of dental caries.
Eleven different laboratory strains of Streptococcus mutans representing the various serogroups were found to produce an average of 6.0 + 4.8 mM acetoin when grown in glucose-containing medium under aerobic conditions. None of the strains produced detectable acetoin when grown anaerobically. A lactate dehydrogenase-deficient mutant produced acetoin both aerobically and anaerobically and in substantially greater amounts than the wild-type strains did. Substitution of mannitol for glucose resulted in decreased acetoin production by wild-type strains and the lactate dehydrogenase-deficient mutant, indicating a role for NADH2 in the regulation of the acetoin pathway. Pyruvate incorporated into the growth medium of a wild-type strain caused acetoin to be produced anaerobically and stimulated acetoin production aerobically. Cell extracts of a wild-type S. mutans strain were capable of producing acetoin from pyruvate and were (partly) dependent on thiamine PP;. Extracts prepared from aerobically grown cells had approximately twice the acetoin-producing activity as did extracts prepared from anaerobically grown cells. The results indicate that acetoin production by S. mutans may represent an auxiliary reaction of pyruvate dehydrogenase in this organism.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.