title: Effects of deuterium oxide on Streptococcus mutans and Pseudomonas aeruginosa.
abstract: A complex aggregation of microorganisms growing on a solid substrate is termed a biofilm and is considered to be an etiological agents. Pseudomonas aeruginosa and Streptococcus mutans are representative bacteria in such biofilms. It is well known that deuterium oxide (D₂O) causes toxic effects on a number of biological systems. We investigated the effects of D₂O on growth and biofilm formation of P. aeruginosa and S. mutans. These bacteria were incubated in medium containing D₂O (100%, 75% or 0%) at 37°C for 24hr, 48 hr or 72 hr. Growth of P. aeruginosa was inhibited by D₂O within the first 48 hr. However, after 72 hr, growth rate was seen to increase in the D₂O-containing medium compared with in medium without D₂O. In contrast, the growth of S. mutans in the D₂O medium was inhibited within 72 hr. The biofilm formation of P. aeruginosa was increased in the D₂O medium. Biofilm formation of S. mutans in the D₂O medium increased compared with in the medium without D₂O, but this increase was only temporary in the case of P. aeruginosa. Compared to biofilm formation in 0% D₂O medium marked as 100%, the biofilm formation rate of S. mutans in 75% D₂O medium was 143% at 24 hr, 146% at 48 hr and 130% at 72 hr. In other D₂O concentration media biofilm formation was lower. In 100% D₂O medium, biofilm formation rate decreased from 114% at 24 hr to 56% at 72 hr. The biofilm formation rate of P. aeruginosa in 100% D₂O medium was 172% at 24 hr, but decreased to 88% at 72 hr. Biofilm formation of P. aeruginosa in 75% and 0% D₂O media showed no significant difference. We consider that these results were due to stress or alteration in bacterial metabolisms.
authors.affiliation: Department of Microbiology, Matsumoto Dental University, Nagano, Japan. kaname8bac@po.mdu.ac.jp
authors.forename: Kaname
authors.initials: K
authors.lastname: Hirai
authors.forename: Mihoko
authors.initials: M
authors.lastname: Tomida
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kikuchi
authors.forename: Ohmi
authors.initials: O
authors.lastname: Ueda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ando
authors.forename: Naokazu
authors.initials: N
authors.lastname: Asanuma
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D041961:Deuterium Exchange Measurement; D017666:Deuterium Oxide / Q000494:pharmacology*; D007700:Kinetics; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000254:growth & development; D053038:Quorum Sensing; D012997:Solvents / Q000737:chemistry; D013295:Streptococcus mutans / Q000187:drug effects* / Q000254:growth & development; D013312:Stress, Physiological
chemical_list: D000900:Anti-Bacterial Agents; D012997:Solvents; D017666:Deuterium Oxide