(A) 15 flatworms were cut in thirds and collected in separate tubes.
(B) Identical numbers of worm samples, both whole and amputated fragments, were either sent to space or stayed on Earth for 32 days.
The researchers also created two sets of control worms that stayed on Earth.
One set was live and sealed in spring water in the same manner as their space counterparts and kept in darkness at 20 degrees Celsius for the same amount of time.
When the researchers amputated both heads from the space-exposed worm, the headless middle fragment regenerated into another double-headed worm The research, led by the Allen Discovery Center at Tufts University, was conducted to study how an absence of normal gravity and geomagnetic fields can have anatomical, behavioral and bacteriological consequences.
The researchers chose to study planarian flatworms (Dugesia japonica), which are often used for studies because of their ability to regenerate when part of their bodies are amputated.
(A) Earth-only control worms exhibit full extension and rapid movement in a petri dish with water (B) Close-up of the Earth-only worms.After the space exposed worms returned to Earth, researchers prepared a second set of worms that were exposed to the same changes in temperature as the space-exposed worms.According to the researchers, the most surprising finding was that one of the amputated fragments sent to space regenerated int a rare double-headed worm.Researchers sent flatworms aboard the International Space Station for five weeks to study how an absence of normal gravity can affect behavior and anatomy - in particular, their ability to regenerate missing parts.
Flatworms were either left whole or amputated, and most surprisingly, one of the amputated fragments regenerated into a double-headed worm.
In more than 18 years of maintaining a colony of more than 15,000 control worms in just the last five years, the Tufts researchers have never observed a spontaneous occurrence of double-headedness.