Scientists at Vanderbilt University have made a remarkable discovery about the hidden abilities of microbial cultures to sense and adapt to changes in their environment, particularly pH fluctuations. Their findings not only showcase the power of lab-driven evolution, but also shed light on the remarkable resilience of certain pathogens and coral symbionts in the face of challenging pH shifts.
Evolutionary Superstars
Sarah Worthan, a postdoctoral researcher and student of the principal investigator on the study, Paul Koch also from UC Santa Cruz. D., which has shown that continuous cycles of feast and famine can allow microbial cultures to evolve a pH-sensing AND response.quantitative.genes4.his.
The secret of this impressive camouflage is a mutation in the Rho protein that stops RNA transcription. When the mutation is present, an arginine amino acid at position 188 of the Rho protein is replaced by histidine with consequences on gene expression dependant on extracellular acidification that are likely mediated through Rho acting as a pH sensor.
What is strikingly interesting, however, is that mutations of arginine to histidine have also been observed in some cancers, implying that this adaptation may offer advantages far beyond only lower life.
Discovering Mother Nature’s Secret Souls
However, the researchers did not end with the lab-evolved microbes. They then set out to look for these pH-sensing mutations in real systems where they were also surprised in some cases to find them.
For all such finding, one in particular was discovered in the neglected pathogen Bartonella baciliformis, causing Carrion’s Disease e.g. in Andean valleys of South America. The bacterium can already sense pH changes because if has to move from the high pH of the insect gut to the neutral pH of human blood after it is injected by a sand fly.
Likewise, they found the mutations in pH-sensitive sponges and their associated microorganisms. For example, these organisms must respond to a large-scale acidic environment such as the one present inside hydrothermal vents or within the bodies of sponges. Professor Thompson said that could be vital in years to come with climate change, “because changing the ocean pH now might tip these organisms off being able to protect themselves from climate change-gone-wrong”.
Conclusion
This pH-sensing both in laboratory-evolved and naturally occurring microbes underscores the extraordinary capacity of adaptation. In addition to shedding light on microbial evolution, the discovery of the genetic and biochemical pathways by which bacteria adapt to environmental changes could lead to new means of gauging how other alterations in their surrounds affect fragile ecosystems. Scenarios such as this highlight the importance of understanding ecosystems when confronting climate change and may be vital in devising strategies to protect the rich tapestry of life on Earth.
