This amoeba eats prey like owls do
Meet the ‘owl slime’ amoeba, which drains its prey and spits out the shell.
The microscopic predator engulfs algae, drains the cells and spits out the shell
The amoeba Strigomyxa ruptor (large yellow-orange cell) engulfs its prey, a Closterium alga (elongated green cell). Unlike all known protists, the amoeba splits open its prey, extracts and consumes the innards, and ejects the undigested cell walls.
A. Suthaus
A microbial predator that stalks the waters of the German geographical region envelopes its victims and leaves their empty husks on the back of. The predator — a newfound amoeba dubbed Strigomyxa ruptor — feeds like no other protist, researchers report the whole way for the duration of the August Ecology and Evolution.
Protozoologists Andreas Suthaus and Sebastian Hess of the University of Cologne in Germany were hunting vampires — microscopic ones, as a minimum. Vampyrellid amoebas eat holes the whole way for the duration of the cell walls of algae and slurp up the insides (SN: eleven/2/15). On the look for to take hold of the protists’ biological diversity, the researchers took water samples from ponds and wetlands near Cologne.
Less than the microscope, one water-filled petri dish changed into teeming with round, reddish, immobile blobs — what vampyrellids look like after feeding. But nearby algae lacked telltale feeding holes.
Time-lapse photography confirmed the amoebas were vampyrellids. But they didn’t feed like other microscopic vampires. The unicellular blobs engulfed and split apart Closterium algae cells, sucking out the insides and tossing the remainder.
“We just couldn’t have self belief it in the origin,” Suthaus says. “Of course, the question becomes, well, how exactly do [the amoebas] do it?”
Feeding experiments revealed that S. ruptor keeps engulfed algae in a different compartment. Enzymes at some stage in this chamber appear to dissolve one side of the prey’s cell wall. The opposite side is connected to the chamber wall. Because the compartment expands, the algae cell swings open like a shelled pistachio. S. ruptor then reaches into itself to scoop up its meal, bundling up and spitting out the empty cell wall.
The odd vampyrellids belong to a previously undescribed genus and species, a genetic analysis suggests. The genus name Strigomyxa, which derives from the conventional Greek words for owl and mucus or slime, is a nod to the microbe’s owllike regurgitation behavior.
“While you see similar pellet-casting in a great deal of alternative organisms, they've more than one cells that fulfill more than one functions. And that's a single cell doing this kind of mechanistic action,” Suthaus says. “It tells us about the ingenuity of evolution.”
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