An abundance of food could trigger this microbe’s strange transformation
A single-celled organism named Gigatrox Euplotes sometimes transforms into a supergiant and eats its normal-sized siblings.
Ben T. Larson
A newly discovered microbe is like a mini version of the Hulk.
Gigatrox Euplotes is unicellular protist which looks like an insect. It feeds on bacteria and other tiny microbes. Sometimes a small number of protists “supergiant” balloon more than twice their usual size. The enormous cells cannibalize their smaller, genetically identical brethren. The triggers for this change aren’t entirely clear, but it tends to happen when there’s enough food, researchers reported May 14 in the journal. Proceedings of the National Academy of Sciences.
The transformation happens in stages, says Ben Larson, a cell biologist at Rensselaer Polytechnic Institute in Troy, New York, who discovered the microbes in gunk scraped from an aquarium filter on Curaçao.
First, “a cell makes a big mouth and it starts running like crazy,” Larson explains. At this point, they’re not very good at cannibalism, but if a future Hulk manages to capture one of his siblings or cousins in his enlarged mouth, “the cell’s body plan resizes, and they grow to become these enormous cannibalistic supergiants.”
And like Bruce Banner and the Hulk, giants and normal-sized cells behave differently. In addition to cannibalism, large cells walk in circles and no longer swim like small cells can.
Giants can return to their previous size by dividing asymmetrically. Hulks can produce nine normal-sized offspring each in a 24-hour period and up to 16 in 120 hours. Normal size E. gigatrox divide only once in 24 hours. With each unbalanced division, the giant cells shrink until they return to their normal size and behavior.
Up to 42 percent of the organism’s genes are involved in transitions from normal to supergiant size and vice versa, Larson and his colleagues found. Learning how protists transform could help researchers understand how simple organisms can develop complex behaviors, and perhaps how multicellular life evolved.
