What if bacteria could talk to each other? What if they had a sense of touch? A new study by researchers at UC Santa Barbara suggests both, and theorizes that such cells may, in fact, need to communicate in order to perform certain functions.
The findings appeared recently in the journal Genes & Development.
Christopher Hayes, UCSB associate professor of molecular, cellular, and development biology, teamed with graduate students Elie Diner, Christina Beck, and Julia Webb to study uropathogenic E. coli (UPEC), which causes urinary tract infections in humans. They discovered a sibling-like link between cell systems that have largely been thought of as rivals.
The paper shows that bacteria expressing a contact–dependent growth inhibition system (CDI) can inhibit bacteria without such a system only if the target bacteria have CysK, a metabolic enzyme required for synthesis of the amino acid cysteine. CysK is shown to bind to the CDI toxin — an enzyme that breaks RNA ó and activate it.
For a cell system typically thought of as existing only to kill other bacteria — as CDIs have largely been — the results are surprising, said Hayes, because they suggest that a CDI+ inhibitor cell has to get permission from its target in order to do the job.
“This is basically the inhibitor cell asking the target cell, ‘Can I please inhibit you?'” he explained. “It makes no sense. Why add an extra layer of complexity? Why add a permissive factor? That’s an unusual finding.
“We think now that the [CDI] system is not made solely because these cells want to go out and kill other cells,” Hayes continued. “Our results suggest the possibility that these cells may use CDI to communicate as siblings and team up to work together; for example, in formation of a biofilm, which lends bacteria greater strength and better odds of survival.”
The study points to the enzyme CysK as the potential catalyst to such bacterial communication — like a secret handshake, or a password. In simpler terms, said Hayes, “If you have the right credentials, you’re allowed into the club; otherwise you’re turned away. There’s a velvet rope, if you will, and if you’re not one of the cool kids, you can’t get in.” …