Enzymes that disrupt bacterial signals shift dental plaque toward health-linked species

Researchers examined how chemical signals shape dental plaque and whether those signals can be manipulated to support a healthier community of mouth bacteria, according to ScienceDaily. The work was published in 2025 in npj Biofilms and Microbiomes. The team included researchers from a College of Biological Sciences and a School of Dentistry.

The mouth hosts roughly 700 species of bacteria, ScienceDaily reported. Many of these microbes exchange chemical signals through a process called quorum sensing, which lets bacteria detect how many neighboring cells are present and coordinate group behavior. Some oral bacteria use molecules known as N-acyl homoserine lactones, or AHLs, to communicate.

The researchers found that bacteria in dental plaque produced AHL signals in aerobic environments, such as above the gumline, where oxygen is available. Bacteria living in anaerobic environments beneath the gumline, where oxygen levels are much lower, could detect those same messages. ScienceDaily reported that this connection mattered because conditions below the gumline can favor bacteria associated with periodontal disease (gum disease).

The team then used specialized enzymes called lactonases to remove AHL signals. Lactonases break down these communication molecules, interrupting the bacterial conversation. When the researchers disrupted AHL signaling, the plaque community shifted toward species more strongly associated with oral health.

"Dental plaque develops in a sequence, much like a forest ecosystem," said Mikael Elias, associate professor in the College of Biological Sciences and senior author of the study. He said pioneer species such as Streptococcus and Actinomyces settle first and are generally harmless and associated with good oral health, while later colonizers include "red complex" bacteria such as Porphyromonas gingivalis, which he said are strongly linked to periodontal disease. Elias said disrupting the chemical signals bacteria use to communicate could allow the plaque community to remain at or return to its health-associated stage.

ScienceDaily reported that the findings suggest carefully chosen enzymes might someday be used to alter the makeup of dental plaque. According to the report, such enzymes could also help maintain a healthier balance of microorganisms in the mouth.