Researchers at UC Berkeley have uncovered a gene cluster that promotes the formation of a strong biofilm in the mouth, potentially enabling good bacteria to outcompete cavity-causing microbes. This breakthrough could lead to novel probiotic treatments for oral health.
Researchers at UC Berkeley have made a groundbreaking discovery that could transform dental health practices. They identified a gene cluster in oral bacteria that promotes the formation of a robust biofilm, offering a potential new avenue to combat cavities without traditional brushing or flossing.
Oral microbiomes are home to hundreds of bacterial species forming communities called biofilms on our teeth. While it’s commonly known that certain bacteria produce acids that erode enamel, leading to cavities, the research team led by Wenjun Zhang, a professor of chemical and biomolecular engineering at UC Berkeley, has delved deeper.
They found that certain bacteria can be either harmful or beneficial depending on their strains and the genetic makeup within those strains.
Instead of categorizing bacteria as strictly good or bad, Zhang’s team employed metagenomic sequencing to identify clusters of genes linked to cavity formation.
One such cluster, found in some strains of the notorious cavity-causing bacterium Streptococcus mutans, produces two molecules facilitating bacterial biofilm formation.
This discovery has been recently published in the Proceedings of the National Academy of Sciences.
“Particular strains belonging to the same species can be a pathogen or a commensal or even probiotic,” Zhang said in a news release. “After we better understand these molecules’ activity and how they can promote strong biofilm formation, we can introduce them to the good bacteria so that the good bacteria can now form strong biofilms and outcompete all the bad ones.”
The potential applications of this discovery are vast.
The identified gene cluster acts like a “specialized” metabolic cassette, producing molecules that enhance bacterial survival. This specialized metabolism is well documented in soil bacteria but has remained largely unexplored in the human microbiome until now.
“These specialized metabolites enhance survival in certain ways,” added co-first author McKenna Yao, a Berkeley graduate student. “Many, for example, are antibiotics, so they can kill other bugs, or others are involved in metal acquisition — they help the bacteria monopolize the resources in their environmental niche. Being able to produce these, especially in a microbial community, helps the bacteria boot out the other guy and guard their resources.”
Understanding these molecules could lead to revolutionary oral health treatments.
For instance, by genetically engineering beneficial bacteria to produce these strong biofilm-forming molecules, harmful bacteria could be outcompeted, reducing the incidence of cavities.
“We are looking for something which is correlated with cavities, with disease. If one day we can prove that, under certain conditions, this is really a bad molecule you want to prevent, we might develop genetic or chemical inhibitors to inhibit their production, so hopefully the bacteria will not make them, and you have fewer cavities,” Zhang added. “Meanwhile, we also look at other molecules correlated with health, allowing a simple strategy to directly engineer the microbes to make more of them.”
One promising candidate for such engineering is Streptococcus salivarius, a bacterium known to promote oral health but lacking in biofilm formation. By integrating the discovered gene cluster into S. salivarius, it might become a more effective probiotic.
Despite these promising avenues, Yao noted that “the best way you can remove the biofilm on your teeth is to brush. We believe that there’s actually a better way of disrupting that biofilm, but we’re just beginning to understand what the complexity is within the mouth.”
The research team aims to continue mapping the specialized metabolites produced by the oral microbiome. The long-term objective is to explore how these metabolites could be harnessed to promote a healthier oral environment.