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Scientists imitate a bacterium's eating habits to unravel common stomach bug

About two-thirds of us have it in our bodies, but for most people, the bacterium Helicobacter pylori (H. pylori for short) never causes any symptoms. In others, it's a common cause of peptic ulcers, and in some cases it can lead to stomach cancer.

H. pylori needs nutrients from our food to thrive, but how the bacterium uses individual nutrients to interact with its surrounding environment, survive, and spread has remained largely unknown.

Scientists at Yale's Microbial Sciences Institute have designed a new technology that mimics the way the common stomach bug eats its food. Their findings, which are published in , could help control the nutritional factors that shape interactions between bacteria and their hosts.

"H. pylori has heavy nutritional needs, but it isn't good at packing its own snacks," explained graduate student Anna Seminara, the first author of the study.

"These bacteria grow in a complex media made from different tissues and nutrients, so we don't know exactly what they're being exposed to and how their environment shapes their behavior."

Previous studies from the lab of senior author Stavroula Hatzios, Associate Professor of Molecular, Cellular and Developmental Biology and of Chemistry, uncovered a nutrient common in the human diet that aided the survival of the cancer-causing bacterium.

Called ergothioneine, or EGT, the known antioxidant was found to protect bacteria from oxidative stress—an imbalance in the body between reactive oxygen species, known as free radicals, and antioxidants—which is a hallmark of many disease-causing infections.

To understand why H. pylori eats the specific molecule and how it responds to it, the scholars attempted to modify the surrounding media where the bacteria thrive. However, there wasn't any way to grow H. pylori without this molecule.

So, they turned to the bacterium itself for clues.

Mimicking the biological machinery used by H. pylori to grab and eat EGT, the scientists set to designing a new technology—likened to a molecular sponge—to remove the antioxidant ergothioneine from the media while retaining all of the other components the bacteria need to grow.

The scientists anticipate that the resulting resin will serve as a baseline material to compare H. pylori growth in different media, uncovering genetic traits that respond to different chemical nutrients. More broadly, the new technology holds promise for the study of microbes with different nutritional requirements.

Merging the fields of chemistry and microbiology, such studies are increasing our basic understanding of host–microbe interactions and generating new leads for therapeutic targets related to gastrointestinal diseases.

Among other resources, the authors relied on mass spectrometry at the West Campus Analytical Core to perform their experiments.