August 26, 2025

Hold on to your lab coats! Scientists at IIT-Bombay have unveiled a fascinating secret: how microbes grow and change depends not just on what they eat, but also on exactly how their meal is served. Imagine giving a microbe the same sugar pieces but in a different shape — suddenly, its whole life plan changes! Led by Prof. Supreet Saini, researchers studied two famous tiny creatures: Escherichia coli (a gut bacterium) and Saccharomyces cerevisiae (the yeast that helps bake your bread). They fed these microbes special sugars — glucose and galactose — mixed simply for some microbes but bonded into complex sugars like lactose and melibiose for others. Over 300 generations, these microscopic diners evolved in totally different ways. The E. coli group with simple sugar mixes grew faster, while those eating complex sugars packed on more biomass. Yeasts showed their own surprise moves. What’s causing these dramatic changes? The genes! Mutations popped up differently depending on which sugar setup the microbes faced. As postdoc Neetika Ahlawat put it, "We didn’t expect these subtle differences to create completely distinct adaptive paths." She adds, "The way a cell responds to a nutrient can influence which mutations are beneficial and what paths evolution can take." But the plot thickens! When these evolved microbes were switched to new sugar environments, their growth had side effects called pleiotropic responses — meaning changes that helped them in one place could affect how they acted somewhere else. Pavithra Venkataraman, a former PhD student on this team, explains, "Evolution is both flexible and constrained. Even with identical diets, microbes could evolve differently, showing evolution’s surprise factor. Yet, their abilities in new environments were predictable based on ancestors’ behavior." Why does all this matter? Prof. Saini says it’s not just cool science. By tweaking microbe diets carefully, scientists might guide evolution to produce super-efficient microbes for food, medicines, or biofuels. Even better, they might block bad germs from evolving antibiotic resistance by limiting their food options! Imagining evolution like a story with countless endings, these IIT-Bombay findings mean we can start to guess which endings are more likely. This is a big step in unlocking evolution’s mysteries, turning unpredictable paths into useful tools for our future.

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Tags: Microbes, Evolution, Iit bombay, E. coli, Yeast, Nutrients,