Which statement best describes how glycosidases are distributed among oral bacteria species?

Which statement best describes how glycosidases are distributed among oral bacteria species?

• A. Evenly distributed across all species
• B. Largely absent from most species
• C. Concentrated in pathogenic species
• D. Glycosidases are randomly distributed across species

Answer: (D)

Glycosidases are enzymes that break down a variety of carbohydrate substrates, and in the oral environment different bacteria encounter different sugars. Because of this, each species can carry a distinct set of glycosidase genes, and strains within a species can differ as well. The presence or absence of these enzymes isn’t uniform, and it’s not limited to pathogens or to any single group. Horizontal gene transfer, gene loss, and adaptation to local niches in dental biofilms create a mosaic pattern of glycosidase capabilities across the oral microbiome. That leads to a distribution where some species have many glycosidases, others have few or none, and the pattern isn’t neatly predictable. Hence, glycosidases are randomly distributed across species. The other statements misrepresent the reality: the enzymes aren’t evenly distributed; many species do possess glycosidases, so they’re not largely absent from most species; and glycosidases aren’t confined to pathogenic species, since commensals and opportunists can also harbor these enzymes.

Glycosidases are enzymes that break down a variety of carbohydrate substrates, and in the oral environment different bacteria encounter different sugars. Because of this, each species can carry a distinct set of glycosidase genes, and strains within a species can differ as well. The presence or absence of these enzymes isn’t uniform, and it’s not limited to pathogens or to any single group. Horizontal gene transfer, gene loss, and adaptation to local niches in dental biofilms create a mosaic pattern of glycosidase capabilities across the oral microbiome. That leads to a distribution where some species have many glycosidases, others have few or none, and the pattern isn’t neatly predictable. Hence, glycosidases are randomly distributed across species.

The other statements misrepresent the reality: the enzymes aren’t evenly distributed; many species do possess glycosidases, so they’re not largely absent from most species; and glycosidases aren’t confined to pathogenic species, since commensals and opportunists can also harbor these enzymes.