Many bacterial communities have settled on the banks of the river of human epithelial cells flowing through your tongue.
Just as human cities combine in areas with different types of communities and purposes, so it turns out that these miniature equivalents gather in your mouths.
A sample of dead tongue cells (gray) surrounded by bacterial communities. (Steven Wilbert / Gary Borisy / The Forsyth Institute).
Spherical, oxygen-loving Streptococci species (green) wander around the outskirts of the 'city' where they are more exposed to the air, while the rod-shaped Actinomyces (red) seem to avoid this perimeter in favor of being closer to the center epithelial cells. Others, such as Rothia (blue), prefer to dwell away from these two boundaries.
“What was really amazing was to see how organized they are. It tells us a lot about how they work together, '' biologist Jessica Mark Welch of Woods Hole Marine Biological Laboratory told Smithsonian Magazine about the phenomenon.
According to Mark Welch, the outer ring of Streptococci (green) appears to create a low oxygen zone within this bacterial metropolis, which is home to species that prefer such anaerobic conditions.
The bacteria secrete protective mucus houses, together forming a thriving, tightly packed biofilm in our tongues.
“Bacteria behave differently in biofilm,” explained Mark Welch. “There are parts of their metabolism that they only include in biofilm, and they tend to be more resistant to antibiotics and environmental changes.”
Images were obtained using a fluorescence imaging technique called CLASI-FISH on tongue scrapings from 21 healthy volunteers. They identified 17 genera of bacteria, prevalent in more than 80 percent of people.
By seeing how these bacteria organize, researchers can learn more about their interactions, how they function, and the roles – good and bad – that they play in our bodies.
The study was published in Cell Reports.
Sources: Photo: (Wilbert et al., Cell Reports, 2020)
