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Michael Blazanin, Jeremy Moore, Sydney Olsen, Michael Travisano: Read the article
Can bacteria swim away from their viruses to escape infection? In a new paper, Blazanin et al. use experimental evolution and mathematical modeling answer this question, finding that bacteria should rarely, if ever, evolve to escape their viral parasites.
In the microscopic world of bacteria and viruses, just like in the animal kingdom, survival of the fittest is law. But what does "fittest" mean when talking about bacterial survival?
While scientists know that bacteria can develop resistance to viruses, a key question remains unanswered: when deadly viruses called phages attack, do bacteria run for their lives? Or do they stand their ground, evolve, and fight back? In a new study, Blazanin, Moore, Olsen, and Travisano demonstrated that bacteria do not flee from their enemies. Instead, they evolve resistance, reinforcing a fundamental rule of microbial evolution: adaptation favors defense over escape.
Scientists have studied the various strategies bacteria have developed against phages for years. These strategies vary from altering their surface proteins to cutting phage DNA with the CRISPR enzyme. While bacteria have evolved sophisticated movement strategies to navigate their environment, the idea that they might actively avoid phages remained largely unsupported. Could bacteria evolve movement-based strategies to escape infection? This is the question the research team answered using a combination of laboratory evolution experiments and mathematical models to study the interaction of the bacteria Pseudomonas fluorescens and its viral predator, phage Phi2.
The results showed that no matter how the phages were distributed in the environment, bacteria never evolved to swim away from them. Instead, they stayed in place and developed resistance. Even in computer simulations, where dispersal might seem like an obvious advantage, bacteria did not evolve to escape—because that advantage disappeared in the presence of phages. So, while bacteria have evolved remarkable movement strategies to navigate their world, escaping from viruses simply is not one of them.
This discovery is significant because it better explains how this tiny microbial world influences so much of our lives. Bacteria-phage interactions shape microbial communities, affect human health, and even play a role in biotechnology and medicine. Understanding how bacteria evolve under viral pressure could inform new treatments, from phage therapy for antibiotic-resistant infections to microbiome research.
So, the next time you hear about bacteria locked in battle with their viral predators, remember: they don’t run—they fight.
Tahirah Williams is a PhD candidate in Quantitative and Systems Biology at the University of California, Merced, under the guidance of Dr. Clarissa Nobile. Her research focuses on understanding the molecular and genetic regulation of Coccidioides, the fungal pathogen responsible for Valley fever, and its interaction with the mucosal immune system. Her work will contribute to a better understanding of host-pathogen interactions. Tahirah enjoys traveling to new places, playing tennis, and cooking new dishes in her free time.
