(ORDO NEWS) — You are very special. You are a person with thoughts, feelings, your own unique experiences.
And you’re so warm and humid – it’s a habitat for trillions of tiny, microscopic bacteria. Your skin, your follicles, your insides are all teeming with little organisms too small to see or feel.
Shhh, it’s all right. It will be better this way. In fact, it’s possible that without them, you wouldn’t be yourself. But some of these little microbes are quite strange – they evolve and adapt to the unique environment that the human body creates.
One such microbe, scientists have found, is a bacterium that lives in your mouth. The Neisseriaceae are a family of microbes, including caterpillar-like species that are found in about half of all humans, and a new study suggests they evolved because this body shape is better suited to the human oral environment.
This is quite interesting and gives us valuable information about the biodiversity in your mouth.
It also has implications for studying the adaptability of bacteria, which is very important for understanding how, for example, to develop more effective antibacterial agents to rid the body of infections.
“Our work sheds light on the evolution of multicellularity and longitudinal division in bacteria,” write the authors of the study, led by cell biologist Sylvia Bulgheresi of the University of Vienna in Austria and microbial geneticist Frédéric Veyrier of France‘s National Institute for Scientific Research (INRS).
“This suggests that members of the Neisseriaceae family may be good models for studying these processes due to their morphological plasticity and genetic traceability.”
While your mouth may seem like a pretty pleasant place for germs to live, it’s not the most favorable environment.
The cells lining the inside of the mouth are constantly dying off and being replaced by new ones, and saliva makes the surface very slippery.
Thus, it becomes more difficult for any creeping creatures to find food for themselves (which, however, did not take long to affect their development – about 700 species live in the human mouth).
Bulgheresi, Veyrier and their colleagues believe that this is why some species of Neisseriaceae have developed an interesting way of reproduction.
The team first used electron microscopy to study the shape of the bacteria in detail, using fluorescence to understand cell growth.
Then they took the rod-shaped Neisseriaceae and made genetic changes to see if they could replicate the evolution from rod-shaped organisms to the caterpillar-like clump types that can be found wriggling in the human mouth.
Their study suggests that the organisms actually evolved from a rod-shaped ancestor.
Today, bacteria divide along the longitudinal axis, or length of their body.
But instead of separating, individual bacteria remain attached to each other, resulting in a segmented cluster wrapped in a common outer membrane, a bit like the bacterial version of the Bibendum talisman.
Some of the microbes in this tiny collective also take on different forms, perhaps in order to fulfill different, separate roles that benefit the group. This may be an example of how an organism evolves from a unicellular to a multicellular organism.
“Multicellularity enables cooperation between cells, for example in the form of a division of labor, and therefore may help bacteria survive food stress,” the researchers wrote in their paper.
The team was unable to reproduce the cluster form of multicellular species such as Conchiformibius steedae or Simonsiella muelleri, perhaps because they were unable to introduce all of the genetic events that led to the caterpillar’s current form. But in the course of the work, longer and thinner individual cells were obtained.
“We hypothesize that over the course of evolution, by redesigning the elongation and division processes, the shape of the cells changed, perhaps in order to better develop in the oral cavity,” Veyrier says.
Genetic tools, the researchers note, will be needed to study bacteria in more detail.
However, an evolutionary approach could be an additional way to study these tiny organisms and how they work, in addition to better understanding the mechanisms behind the symbiotic relationship they maintain with their (comparatively) gigantic mammalian hosts.
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