Role of urease enzymes in stability of a 10-species oral biofilm consortium cultivated in a constant-depth film fermenter - PubMed (original) (raw)

Role of urease enzymes in stability of a 10-species oral biofilm consortium cultivated in a constant-depth film fermenter

Man Shu et al. Infect Immun. 2003 Dec.

Abstract

Using a 10-species oral biofilm consortium and defined mutants, we show that high-level capacity to generate ammonia from a common salivary substrate is needed to maintain community diversity. This model appears to be suitable for the study of the effects of individual genetic determinants on the ecology of oral biofilms.

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Figures

FIG. 1.

FIG. 1.

Wild-type biofilms formed in the presence of urea. Biofilms were cultivated in complete BMMUG medium for the entire 11-day period. Organisms were recovered from the CDFF and enumerated by viable counting on selective media as detailed in the text. Viable counts are expressed as the average of the log CFU obtained per pocket, which provides the number of organisms that could be recovered from each of the five recessed pockets in the PTFE pans. Error bars indicate standard deviation. The data represent results from at least two complete runs of 11 days, and all platings were done in triplicate using three separate PTFE pans.

FIG. 2.

FIG. 2.

Wild-type biofilms before and after removal of urea from the medium. Biofilms were cultivated in complete BMMUG medium for 7 days and then in BMMG for days 8 through 11. Organisms were recovered from the CDFF and enumerated as detailed in the text and in the legend to Fig. 1.

FIG. 3.

FIG. 3.

Biofilms formed with the urease-deficient Streptococcus salivarius. Biofilms were cultivated in complete BMMUG medium for 7 days and then in BMMG for days 8 through 11. Organisms were recovered from the CDFF and enumerated as detailed in the text and in the legend to Fig. 1.

FIG. 4.

FIG. 4.

Biofilms formed with the urease-deficient Actinomyces naeslundii. Biofilms were cultivated in complete BMMUG medium for 7 days and then in BMMG for days 8 through 11. Organisms were recovered from the CDFF and enumerated as detailed in the text and in the legend to Fig. 1.

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