Scientists are unraveling the molecular barcode used by bacteria to secrete toxins. In the intricate world of microbiology, bacteria have de...
![]() |
Scientists are unraveling the molecular barcode used by bacteria to secrete toxins. |
In some bacterial species, quorum sensing adds another layer to the molecular 'barcode.' This communication system enables bacteria to coordinate toxin secretion based on population density.
![]() |
The graphic shows how bacteria exotoxins cause diseases. |
Toxin secretion is not a random or chaotic process; instead, it follows a precise molecular 'barcode' that guides the bacteria in deploying these potent weapons. This 'barcode' essentially consists of a series of molecular signals and cues that orchestrate the entire process of toxin synthesis and release.
![]() |
Types of toxins produced by bacteria. |
Sure enough, there was. Each toxin shared a "domain," which Whitney colloquially compares to a barcode. He says that while the barcode was shared by all three toxins under study, it was absent from the other three thousand or so proteins in the bacteria, indicating that it serves as the export signal.
Shah, who co-first authored the study with Klein, says the team was able to prove this concept experimentally through a combination of genetic, biochemical, and structural approaches, including important "X-ray crystallography studies" that allowed them to purify the proteins and get a clearer view of the so-called barcodes and how they functioned.
The research team believes that this new information could eventually have a range of important biotechnology and infectious disease-related applications. In particular, Shah notes that the findings are relevant to our understanding of an array of gram-positive pathogens, including the kinds of bacteria responsible for serious infectious diseases like tuberculosis and listeriosis.
"A lot of pathogens use this system," Shah says. "Therefore, our discovery has important implications on our understanding of the virulence strategies used by a wide range of human pathogens."