MAR 22, 2021 5:54 PM PDT

A Cavity-Forming Germ Gets a Little Help From a Gene Cluster

WRITTEN BY: Carmen Leitch

There are many microbes that live in the human mouth, and while some are harmless, others like Streptococcus mutans are a major cause of tooth decay. It's thought that infants easily acquire these microbes, usually from caregivers, at an early age, so we have to brush our teeth to keep the levels of these and other strains of cavity-causing microbes low. When we eat sugary foods, S. mutans can digest the sugars, producing acids that damage tooth enamel, which leads to cavities. These bacteria can also easily get to hard-to-reach places in the mouth and take up residence there.

Streptococcus mutans bacteria. / Credit: CDC/ Dr. Richard Facklam

S. mutans is a tenacious microbe; it can form biofilms, which are microbial colonies that are much tougher and harder to remove than individual microbial cells. Reporting in Nature Chemical Biology, scientists have now assessed different strains of S. mutans isolated from various samples of plaque.  

The study's identified a cluster of bacterial genes in the S. mutans microbes that is directly linked to the ability to form tough biofilms. This gene cluster is called muf and it encodes for a complex of molecules that promotes biofilm formation, called mutanofactin-697. 

Mutanofactin-697 can bind to both S. mutans cells and free-floating DNA, so they will cluster together. At the time time, mutanofactin-697 helps bacterial cells repel water while encouraging the bacteria to attach to surfaces, like teeth. All these features help the S. mutans form nasty biofilms that are difficult to remove and lead to cavities and tooth decay.

This study was conducted by a team of researchers including Pei-Yuan Qian at the Hong Kong University of Science and Technology (HKUST) and Wenjun Zhang at the University of California, Berkeley.

"Our findings provide the first example of a microbial secondary metabolite promoting biofilm formation via a physicochemical approach, highlighting the significance of secondary metabolism in mediating critical processes related to the development of dental caries," said Qian, who is the David von Hansemann Professor of Science at HKUST.

Learning more about how cavities form will help scientists find ways to prevent them. Tooth decay is thought to cost the world about $442 billion per year.

Sources: HKUST, Nature Briefing, Nature Chemical Biology

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
APR 05, 2021
Microbiology
Salmonella Outbreaks Linked to Bird Feeders, Pet Turtles
APR 05, 2021
Salmonella Outbreaks Linked to Bird Feeders, Pet Turtles
Many types of bacteria often live harmlessly in and on animals and humans, but some bacteria pose a threat. Salmonella b ...
APR 12, 2021
Cell & Molecular Biology
Deep Subsurface Microbes Are "Living Fossils"
APR 12, 2021
Deep Subsurface Microbes Are "Living Fossils"
Researchers were shocked when they saw the results of a genetic analysis comparing various microbes from around the worl ...
APR 19, 2021
Microbiology
Gas-Generating Microbes Highlight the Diet - Microbiome Link
APR 19, 2021
Gas-Generating Microbes Highlight the Diet - Microbiome Link
Researchers are learning more about how different species of bacteria in the human gut microbiome play a role in metabol ...
MAY 14, 2021
Microbiology
An Imaging Tool for Seeing Bacterial Infections in the Body
MAY 14, 2021
An Imaging Tool for Seeing Bacterial Infections in the Body
Researchers have created an imaging agent that will allow scientists and clinicians to visualize a bacterial infection c ...
JUN 01, 2021
Microbiology
A Closer Look at a Potential Bioweapon
JUN 01, 2021
A Closer Look at a Potential Bioweapon
Francisella tularensis is a naturally occurring bacterium found throughout the Northern Hemisphere that is extremely vir ...
JUN 04, 2021
Cell & Molecular Biology
Even When They're Outside the Brain, Infections Worsen Alzheimer's
JUN 04, 2021
Even When They're Outside the Brain, Infections Worsen Alzheimer's
It's thought that inflammation is closely connected to cognitive decline, and neuroinflammation plays a role role in the ...
Loading Comments...