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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 7711

Anne Fleury, Francine Iftode, Ghislaine Fryd-Versavel, Jean-Jacques Curgy, and Jean Genermont; Stable and Unstable Morphological states generated by Cadmium Treatment and Heat shocks in Euplotes (Ciliata, Hypotrichida) with some References to Tetrahymena pyriformis (Ciliata, Hymenostomatida). Protistologica XIX(4):577-586, 1983

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The present study is a dynamic and comparative analysis of the various morphological states obtained in the course of cadmium treatment or heat shock. During cadmium treatment, the two Ciliates Euplotes vannus and Tetrahymena pyriformis exhibit similar reactions, i.e. regenerating processes (oral substitution in Tetrahymena and physiological reorganization in Euplotes) and abortive divisions generating numerous abnormalities. Beyond these physiological reactions, the dynamics of the various monster forms points out the specific organization of each genus. Using heat shock in Euplotes, it was possible to understand the genealogy of the various abnormal forms and to define: a) the stable morphogenetical states (singlet, doublet, triplet) and b) the dynamics of the unstable forms, endowed with excess ventral and/or dorsal infraciliature, which unvariably recover the singlet state after a few fissions. In Tetrahymena, the experimental conditions restricted the analysis to one generation; the results obtained here confirm previous studies on dynamics or abnormal forms, specially the singlet-doublet chimera which can progress either toward the singlet or the doublet state. These results are compared to those obtained in other Ciliates and discussed at the cellular level with respect to the cytotaxic theory.