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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 316

Amsellem, J. and Pierre Clement; Correlations between ultrastructural features and contraction rates in rotiferan muscle. I. Preliminary observations on longitudinal retractor muscles in Trichocerca rattus. Cell Tissue Res. 181:81-90, 1977

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Notes

The Rotifer Trichocerca rattus has striated longitudinal retractor muscles. These muscles can be divided into two categories: 1. The central and ventral retractor muscles which, after fixation, are found in a supercontracted state: they probably contract very quickly. 2. The lateral retractor muscles which are in a relaxed state after fixation. However, if the animal is mechanically stimulated before fixation, these are also fixed in a contracted state: so, normally, these muscles probably contract more slowly than the first category. In the relaxed state, thin myofilaments of the lateral retractor muscles are folded at the I band level; this a consequence of their compression provoked by the contraction of central and ventral retractor muscles. In muscles of the first type, the thick myofilaments are shorter (less than 2 mu) than in the second type (2.5 mu).