About our worms

Asexual worms: The Schmidtea mediterranea (Smed) asexual clone CIW-4 (a.k.a. C4) is a clonal population originally derived by Dr. Sánchez Alvarado, at the Carnegie Institute of Washington. The asexual biotype is characterized by a chromosomal translocation abrogating both primary and secondary sexual characteristics. These worms reproduce by fission, and were personally collected in Spain by Dr. Sánchez Alvarado, at a site which has since been developed. There is no commercial source for this exotic species. C4’s have been the “workhorse” clone of S.med research, and are maintained in large numbers at the Stowers Institute for Medical Research in Kansas City, Missouri. In general, we are happy to assist qualified researchers and postsecondary educators in obtaining a starter colony for work in which this species is required, with a few conditions. Educators and those interested in alternate species should also explore the Planarian Education Resource.

To request C4 please see the worm request form or email planosphere@stowers.org

Our sexually reproducing S. mediterranea stocks are descendants of animals collected in Sardinia by Dr. Maria Pala in 1999. We maintain Smed in 1x Montjuic water at 20˚C in the dark, and feed them homogenized beef liver as described in (Cebrià and Newmark, 2005). Our worms are currently housed in static and recirculating cultures. Static cultures subjected to intensive cutting and/or feeding regimens are supplemented with 100 µg/mL gentamicin sulfate (Gemini Bioproducts, #400-100P). For further information about recirculating systems for planaria culture, please contact SIMR Aquatics Facility Supervisor Shane Merryman (mme@stowers.org).

Worms maintained in static culture are stored in constant darkness in incubators at 20˚C.

Flush flow recirculating system used for Smed sexual worm culture. Each tank contains fourteen cylinders, and each cylinder houses eight worms.

Egg capsules are collected daily from outbred cohorts of sexually mature adults cultured at low density (~6-8 animals per 400 mL culture), and are stored in dated petri dishes at 20˚C in constant darkness until use. At collection, egg capsules are deemed to be 1 day post egg capsule deposition. To promote fertility, sexually mature animals used for egg capsule collections are replaced every 3-4 months with either juveniles (6-8 weeks post hatching) or adult regenerates (6-8 weeks post cut).



Cebrià, F., and Newmark, P.A. (2005). Planarian homologs of netrin and netrin receptor are required for proper regeneration of the central nervous system and the maintenance of nervous system architecture. Development 132, 3691-3703.