This composite image of a scanning electron micrograph shows a large male worm
that has mated with a female and enclosed her in his gynacophoric canal. The skin
of the male is peeled back to reveal the stem cells (orange) underneath.

Image by Jim Collins, Ana Vieira and Phillip Newmark, University of Illinois at

The Secret to (Worm) Longevity

Schistosomes are parasitic flatworms that burrow through human skin and lay eggs that eventually lodge in major organs. As if that isn’t bad enough, the worms thrive in their hosts for decades. A discovery by HHMI investigator Phillip Newmark may help shorten this parasite’s lifespan.

Newmark studies planarians, relatives of schistosomes, in his laboratory at the University of Illinois at Urbana–Champaign. Planarians have extraordinary regenerative powers—they can replace lost body parts by calling on a reserve of stem cells called neoblasts. Postdoctoral fellow Jim Collins and Newmark had a hunch that schistosomes might use similar cells to repair damaged tissues, allowing them to live longer lives.

They were right. The researchers found similar actively dividing cells. “The cells we found in schistosomes look remarkably like planarian neoblasts,” explains Newmark. And they can give rise to multiple cell types. The scientists published their results February 28, 2013, in Nature.

Newmark says the schistosome stem cells aren’t necessarily the sole reason the parasites survive for so many years. But their ability to replenish multiple cell types likely plays a role. With more work, scientists may be able to figure out how to target the schistosome stem cells and shorten the parasite’s lifespan.

Scientist Profile

University of Wisconsin–Madison
Developmental Biology, Parasitology

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