Researchers from Cornell University recently released a study of firsts. In the process they have revealed groundbreaking knowledge of how some microbes prosper in extreme and often disturbed ecosystems. The research, appearing in the Proceedings of the National Academy of Sciences, explores the dynamics between antagonistic and non-antagonistic strains of Saccharomyces cerevisiae. This species is better known by its other name – budding yeast. As their results indicate, sometimes under very precise conditions, mind you, the pacifist bugs are simply better than the nasty ones.
Andrea Giometto, assistant professor of civil and environmental engineering at Cornell, is happy to take that honor as the paper’s co-senior author. He’s the partner of Alexander Vladimirsky, an associate professor of mathematics in the College of Arts and Sciences. Natural strains of bacteria. One was a “killer” strain that makes toxins to kill off competitors, and the other was a “sensitive” strain that doesn’t play aggressive farmer.
The research team carried out a series of dilutions to determine the survival rate of each strain. They developed a detailed protocol to measure the few surviving cells one by one. This unique experimental setup allowed the researchers to directly observe the personal effects of antagonistic behavior on microbial survival. Their interest resided in how this behavior adapts to variable habitats.
MingYi Wang, a Ph.D. student under Vladimirsky’s supervision, was key to this research. My lab mates and I generated a time-progressive movie depicting the competition dynamics between the sensitive and killer variants through successive dilutions. Objects 5 & 6 This schematic illustration helped show the mechanics behind the microbial world’s interactions with no basal mortality.
Giometto noted the central question guiding their research: “The big overarching question was: When is it advantageous to be antagonistic, and when is it detrimental?” He shared that oppositional behavior is often rewarded in the short term. It frequently does so at a substantial metabolic cost, which can constrain potential growth benefits.
Vladimirsky further elaborated, stating, “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 toward dividing faster.”
Rebecca’s study was important for shedding light on how the frequency of disturbances of the environment influences microbial strategy. Vladimirsky explained that “when the dilution times are random, the antagonists could get quite a substantial benefit from being selective about when to produce toxin.” He noted that “when the dilutions happen right on schedule, our computational experiments showed that the benefit they could derive from being selective is much smaller.”
Giometto concluded by emphasizing the findings’ implications for microbial survival strategies: “What we see is that when the environment gets diluted very frequently—in our case, every day—the non-antagonistic cells are better off than when they’re diluted more seldom, which for us was every 48 hours.”
In doing so, this research sheds new light on microbial interactions. It opens up interesting questions about biological competitive behavior. The study’s DOI is 10.1073/pnas.2424372122.