Evaluation of tentacle regeneration as a biological assay inHydra

  • Valerie Raabe Flechtner
  • Georgia Elizabeth Lesh-Laurie
  • Michael Kenneth Abbott


Tentacle number in non-buddingHydra attenuata, randomly selected from mass culture varies <0.5 tentacles over a 3 month period. Replicate samples of untreated regenerates (n=50–60), however, show some variability in mean tentacle number regenerated (Sx0.13–0.15). The variability is similar whether experiments are performed using randomly selected animals or animals with identical tentacle numbers. The variability is, further, not the result of profound differences in the time of tentacle initiation in individual animals.

Addition of 10−5 M glutamate or a methanol extract to the assay medium results in both an earlier appearance of tentacles and in more tentacles being regenerated during early time periods. The mean tentacle number of methanol extract-treated animals is significantly higher than the mean tentacle number of either control or glutamate-treated animals at all time periods examined.

The distribution of tentacle number classes among regenerates is normal in control and glutamate-treated animals but nonparametric in methanol extract-treated animals, making statistical analysis of the data using Student'st-test in-appropriate. The usefulness of the Mann WhitneyU and Kruskal-Wallis tests is discussed, as is the appropriateness of tentacle regeneration as an assay forhydra morphogens.

Key words

Hydra Regeneration Bioassay Morphogen Statistical analysis 


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Copyright information

© Springer-Verlag 1981

Authors and Affiliations

  • Valerie Raabe Flechtner
    • 1
  • Georgia Elizabeth Lesh-Laurie
    • 1
  • Michael Kenneth Abbott
    • 1
  1. 1.Department of BiologyCleveland State UniversityClevelandUSA

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