A study of peptide hormones in the brain of a seemingly primitive flatworm reveals the surprising complexity of its nervous system and opens up a new approach for combating a major parasitic disease, researchers report.
The planarian flatworm, Schmidtea mediterranea, is perhaps best known for its prodigious powers of regeneration. Cut it in half (lengthwise or crosswise) and each fragment will regrow its missing parts, including its brain. The planarian is of interest to those studying reproduction because it exists in sexual and asexual varieties. Asexual planaria reproduce by splitting into two pieces and then regenerating. Sexual planaria are hermaphroditic. Some planaria can even switch between the sexual and asexual forms.