Possible Effects of Altered "g" Forces on Behavior of Planarian

Friday, February 12, 2016
Alicia Porile, John Adams High School, South Bend, IN
Gravity is a fundamental force that has been influencing all life since the beginnings of time.  It is an attractive force that acts on all objects and relies on the relationship between the mass of the objects and the distance between them. Without gravity, simple life functions like walking and births could be made impossible.  Centrifuges and clinostats, as well as space shuttles, are used to study increased and decreased “g” forces.  A “g” force is not the actual force of gravity, but is the way of quantifying the force felt by the object as related to gravity. A research organism suitable for studying the effects of gravity is the planarian flatworm. The planarian worm moves by using its cilia and twisting its muscle layer. The behavior of the worm can be assessed using a grid. Planaria have the unique ability to regenerate.  This is due to cells called neoblasts that exist within the worms.  The purpose of this investigation was to determine the effect that gravity has on the behavior and regeneration of planarian flatworms.

The behavior of planarian worms was monitored by counting the lines per 3 minutes that each worm crossed on a 1mm by 1mm grid.  Two experimental groups, centrifuged at 7,000 g and 14,000 g for a five-minute period, were assessed along with the control.  Results were analyzed using the Student T-statistical test. The regeneration of the planarian worms was assessed using a control and two experimental groups centrifuged at 7,000 g and 14,000g for a ten-minute period.  They were transversally cut post-centrifugation, and regenerated tissue was measured initially and at +7 and +14 days.  Results were analyzed using a Student-T statistical test. Results showed that hypergravity detrimentally affected both the behavior and the regenerative capabilites of the planarian worms.  Control worms generally crossed more lines and regenerated faster than both experimental groups.  The experimental posterior ends regenerated faster than anterior ends.