Evolution has an agenda. Organisms receive cues from the environment and adjust to better survive and thrive based on that input. When it comes to pathogenic bacteria that agenda is far from benign — they survive and thrive by making us sick.
An analysis of the evolution of the harmful bacteria that live in the upper portion of the throat, published in the journal PLOS Genetics, suggests that their shape has changed over time. Specifically, the bacteria changed from a rod- or stick-like shape to spheres, which allowed the composition of certain molecules on their surface to transform. This shift may have taken place to give the bacteria better odds at slipping past our immune system defenses, according to researchers.
"We have long believed that the shape of bacteria was a fixed variable," Frédéric Veyrier, PhD, co-author of the paper and professor at the INRS-Institut Armand-Frappier Research Center in Quebec, said in a statement. "We even use it as a way to classify bacteria. Some mystery remains as to how the various species regulate their shape. This research demonstrates that the environment in which the bacteria evolve has an impact on their morphology. These are exciting results because we were able to identify the same change in two different species — and therefore its impact could be a key aspect in the specific way these pathogens are adapting to the human nasopharynx."