A new study has shown that the behavior of oral bacteria colonies is not much different from how we humans settle in cities.
There is a reason bacteria live in 'colonies', and the more we learn about how these tiny architects build their communities, the more familiar their behavior seems to us.
A new study that looks at how multiple individual settlers turn into microcolonies has revealed patterns and growth patterns that reflect our own urban leanings.
“We watched hundreds of bacteria spread across the surface from their initial colonization to biofilm formation,” says Hyun Ku of the University of Pennsylvania.
“And we see that the spatial and structural characteristics of their growth are similar to what we see in urbanization.”
As in nature, bacteria in the mouth live in complex structures known as biofilms. In fact, 99.9 percent of prokaryotes live with millions of other neighbors in one of these settlements.
Biofilms are everywhere, but if you have them on your teeth, we call them plaque. In this dense and sticky sediment, bacteria are protected from environmental influences such as toothpaste, dental floss or even antibiotics.
It accumulates when several individual settlers turn into microcolonies, but exactly how this happens remains unexplored.
ature Communications, 2020
Using the oral bacterium Streptococcus mutans, the researchers showed that microbial cells deposited randomly and regardless of surface type. However, only a fraction of the colonizers actually begin to cluster, expanding their scale 'by combining neighboring bacteria into densely populated microcolonies'.
“We thought most individual bacteria would grow,” Ku says. 'But the actual number was less than 40 percent, and the rest either die off or are absorbed by the growth of other microcolonies.'
As soon as clusters arise, something really curious happens: they begin to interact with each other, grow and combine into densely populated micron-scale microcolonies, which further expand and merge, forming a biofilm superstructure.
This collaboration is interesting, as previous studies have reported bacterial competition in other species, especially when nutrient deficiencies are present.
In this case, the nutrients only affected the actual colony formation. After that, “individual microcolonies (distant or in close proximity) continued to grow without interruption until they merged with each other, and the combined structures behaved and grew as a single new harmonized community,” the researchers write.
It was only when more antagonistic alien species were introduced that this seemingly peaceful unit was affected and the growth of microcolonies was slowed down.
“These communities (microcolonies) can expand and merge with each other in a spirit of cooperation, without competition between neighboring communities,” the authors conclude.
This is a type of growth that indicates 'communal behavior between microorganisms', and it is similar to human urbanization, where some settlers remain stationary while others turn into villages, which further expand into densely populated micro-colonies or cities, then merge into megacities .
“This is a useful analogy,” says Ku. “We're not saying bacteria are anthropomorphic. But this prospect of biofilm growth gives us a multiscale, multidimensional picture of how they grow that we haven't seen before. '
The research was published in Nature Communications.
Sources: Photo: CDC / Public Health Image Library
