Researchers at UT Southwestern Medical Center have discovered how a bacterium that infects people after they eat raw or undercooked shellfish creates syringe-like structures to inject its toxins into intestinal cells. The findings, published in Nature Communications, could lead to new ways to treat food poisoning caused by Vibrio parahaemolyticus.
The latest findings build on the work of a previous study by the Orth lab. Researchers tagged components of the V. parahaemolyticus T3SS2 with fluorescent markers and used super-resolution microscopy to track their locations as the bacteria were grown in different conditions. The researchers discovered that when V. parahaemolyticus is exposed to bile acids – digestive molecules in the intestines – the bacteria move DNA containing the T3SS2 genes close to their membrane.
Then, at the exact site where the T3SS2 is needed, V. parahaemolyticus transcribes that DNA into RNA, translates the RNA into protein, and assembles the components of the T3SS2 through the membrane in a process known as transertion.
These steps were previously thought to occur in more disparate locations around a cell, but pulling the machinery together into one place on the bacterium’s membrane likely helps V. parahaemolyticus more quickly and efficiently build the T3SS2 and infect cells. Since other disease-causing gut bacteria contain molecular components similar to V. parahaemolyticus, the phenomenon of transertion may be widely used, the researchers hypothesize.
