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The photobiology of Hydra’s periodic activity

  • Cloe Taddei-Ferretti
  • Carlo Musio
  • Silvia Santillo
  • Antonio Cotugno
Part of the Developments in Hydrobiology book series (DIHY, volume 178)

Hydra’s response to a light pulse is a phase shift of the state of bioelectric activity correlated with the periodic shortening-elongation behaviour. The direction and absolute value of a phase shift depend on intensity, direction, application phase (along the periodic activity state), and wavelength of the light pulse. Repetitive pulses entrain the behavioural cycle. The period of the behavioural cycle depends on intensity and wavelength of steady background illumination; however, the light effect is not exerted isotropically along all the phases of the behavioural cycle. Inferences are drawn on light influence on the behaviour pacemaking mechanism. By using polyclonal antibodies against squid rhodopsin, an opsin-like protein has been identified in the ectodermal layer, presumably in sensory cells.

Key words: periodic behaviour, phase shift, photosensitivity, light wavelength, photopigments, opsin-like protein

Keywords

Light Pulse Rhythmic Activity Visual Pigment Bioelectric Activity Application Phase 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • Cloe Taddei-Ferretti
    • 1
  • Carlo Musio
    • 1
  • Silvia Santillo
    • 1
  • Antonio Cotugno
    • 1
  1. 1.Istituto di Cibernetica ‘E. Caianiello’Italy

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