Many types of cells can feel the flow, just as our skin cells can feel the difference between a gentle breeze and a strong wind. But we depend on feeling the force involved, the push of the air against us. Without that push, we cannot distinguish speed; when the windows are closed, our skin cannot feel any difference in the air force, whether we are sitting in an office, in a high-speed car or on a cruise plane. But now, a team of Princeton researchers has discovered that some bacteria can, in fact, detect flow velocity independently of force. Her article appears in the online journal Nature Microbiology.
"We have designed the bacteria to be speedometers," said Zemer Gitai, the biology professor Edwin Grant Conklin of Princeton and the lead author of the paper. "There is an application here: we can really use these bacteria as flow sensors, if you want to know the speed of something in real time, we can tell you."
The bacteria with the built-in speedometer, Pseudomonas aeruginosa, are a ubiquitous pathogen, found in and on bodies, in water currents, in the soil and in all hospitals. The Center for Disease Control and Prevention classifies Pseudomonas as a "serious threat," responsible for more than 50,000 infections associated with medical care per year, of which 6,700 are resistant to antibiotics and 440 are fatal.
"In some hospitals, surgeons use chemical disinfectants, basically Purell, instead of washing them because Pseudomonas loves to grow in the pipes," Gitai said. In fact, Pseudomonas is almost always surrounded by fluid fluids, either in a stream or in any of the systems of the human body that involve flow (the bloodstream, the urinary tract, the gastrointestinal tract, even the lungs) or in systems of pipelines. or medical equipment such as catheters, one of the main vectors for postsurgical infections.
"That's old news," said Gitai. "What we discovered is that the Pseudomonas not only flow, but can actually feel and respond to that flow, that's a big problem, if they are in flux, they can change their 'behavior', if they want, according to the feeling that they are flowing.”
Joseph Sanfilippo, a postdoctoral researcher in the Gitai laboratory, and Alexander Lorestani, a graduate of 2017, are the main authors of the article. Together, they determined that bacteria can detect and even measure the flow velocity of nearby fluids to activate a set of genes.
By: Preeti Narula