Microbial Pacifists Outperform Aggressors in Harsh Environments
Cornell Study Reveals Strategy Shift for Survival
In the microscopic realm, aggression often pays, but a new study suggests a gentler approach can be more advantageous when conditions turn tough. Researchers at Cornell University have discovered that microbes favoring peace over toxic competition are more likely to survive and flourish during severe environmental disruptions.
When Peace Prevails
The findings, published in the Proceedings of the National Academy of Sciences, challenge the notion that constant conflict is always the winning strategy for microorganisms. Assistant Professor of Civil and Environmental Engineering **Andrea Giometto**, a co-senior author, explained the delicate balance.
“Microbes often pay a metabolic cost to display antagonistic behavior, so they have to invest some energy into that. Especially when there are opportunities for growth and still very few microbes around, it might actually be better to redirect that energy towards dividing faster.”
—Andrea Giometto, Assistant Professor, Cornell Engineering
The research project began when doctoral student **MingYi Wang** explored stochastic modeling in **Giometto’s** course. **Wang** then brought his Ph.D. adviser, Professor of Mathematics **Alexander Vladimirsky**, into the collaboration, recognizing the potential of their mathematical tools.
Boom-and-Bust Survival
While aggressive microbes can dominate in stable environments, fluctuating conditions favor pacifists. These disruptions can mimic events like antibiotic treatments in the gut or the physical removal of dental plaque. To replicate these volatile scenarios, the team used Saccharomyces cerevisiae, commonly known as budding yeast.
They cultivated both a “killer” and a “sensitive” strain daily, followed by a dilution process to measure survival rates. This cycle was repeated to observe the long-term effects of frequent environmental changes.
Modeling Complex Dynamics
Computational modeling allowed the researchers to investigate factors difficult to test experimentally, such as varying dilution frequencies and the role of predictability. The study highlighted how strategies like quorum sensing, which enables microbes to attack only when triggered by specific cues, can be more or less beneficial depending on the environment’s stability.
“When the dilution times are random, the antagonists could get quite a substantial benefit from being selective about when to produce toxin. In contrast, when the dilutions happen right on schedule, our computational experiments showed that the benefit they could derive from being selective is much smaller.”
—Alexander Vladimirsky, Professor, Cornell University
Understanding these trade-offs could pave the way for designing more effective probiotics, capable of modulating their behavior to combat infections in diverse conditions. The principle may even extend beyond microbes to other competitive systems.
This research was supported by grants from the National Institute of General Medical Sciences, the Human Frontier Science Program, the National Science Foundation, and the Air Force Office of Scientific Research. For instance, the microbiome of the human gut contains trillions of bacteria, and disruptions can lead to various health issues, underscoring the importance of understanding microbial community dynamics (Nature Reviews Microbiology, 2018).
