Inter-related determinants of oral malodor were measured over a three-hour period in 30 human subjects after mouthwash treatments. Re-odoration was important to mouthwash activity for 30 min. At post-treatment times of 60-180 min, the anti-odor activity of the product is due solely to its anti-microbial action.

Fusobacterium nucleatum is a Gram-negative anaerobic rod-shaped bacterium frequently isolated from human dental plaque. It is capable of the desulfuration of cysteine and methionine, resulting in the formation of sulfide and thiol volatiles, respectively. Intact cells, as well as cell-free extracts produced by French pressure cell lysis of F. nucleatum, hydrolyzed radiolabeled cysteine to produce sulfide, pyruvic acid, and ammonia. The hydrolysis products of radiolabeled methionine were a volatile thiol, ketobutyrate, and ammonia. Both activities were associated with the cytoplasmic component, not the membrane. The desulfuration mechanisms are heat-labile, inhibited by the presence of excess substrate, and rates are dependent upon substrate concentration. These dissimilar pathways by F. nucleatum can account in part for the presence of sulfur-containing volatile products that occur in the mouth.

Oral odorigens were quantitated by specific, functional assays; oral malodor was simultaneously measured organoleptically. An antiseptic mouthwash was found to depress malodor and populations of odorigenic bacteria for at least two h. These results support the hypothesis that the anti-odor properties of the product are related to its anti-microbial activity.

mechanism for spheroplast formation in Bacillus cereus and Escherichia coli. J. Bacteriol. 90:1355-1364. 1965.-Spheroplasts of Bacillus cereus strain T and Escherichia coli B were prepared by incubating early log-phase cells in appropriate buffers and stabilizers for 3 hr at 30 and 37 C, respectively. Upon incubation in 0.05 M tris(hydroxymethyl)aminomethane buffer osmotically stabilized with 16% polyethylene glycol at pH 7.5, 99% of the B. cereus cells formed spheroplasts; 90% of the E. coli cells were converted to spheroplasts in 0.4 M sodium acetate buffer osmotically stabilized with 1.6 M sucrose at pH 6.0. The extent of spheroplast formation was determined by phase-contrast microscopic examination, by measuring the rate of fall of optical density in the reaction mixture when subjected to osmotic shock, and by viable intact cell counts. The effect of a selected group of metabolic inhibitors on the autolytic system of B. cereus and E. coli has been examined. B. cereus and E. coli wall components comprising 26% of the dry weight of the original cellular material were recovered from dialyzed fractions by precipitation in 70% ethyl alcohol. Chemical and chromatographic analysis of cell-wall hydrolysates from B. cereus and E. coli indicated the presence of glucosamine, alanine, lysine, glycine, aspartic acid, diaminopimelic acid, glutamic acid, and muramic acid.

Odorigenic gram-negative anaerobes in human gingival crevices were significantly decreased for up to 120 minutes after rinsing with an antiseptic mouthwash. This observation parallels clinical measurements of the antiseptic effect on oral malodor and suggests that its odor-decreasing properties are related to its antimicrobial action in the mouth.