Muscle cells in the tiny marine Antarctic mite Halacarellus thomasi: an ultrastructural and immunocytochemical study

Citation
M. Royuela et al., Muscle cells in the tiny marine Antarctic mite Halacarellus thomasi: an ultrastructural and immunocytochemical study, POLAR BIOL, 23(11), 2000, pp. 759-765
Citations number
41
Categorie Soggetti
Biology
Journal title
POLAR BIOLOGY
ISSN journal
07224060 → ACNP
Volume
23
Issue
11
Year of publication
2000
Pages
759 - 765
Database
ISI
SICI code
0722-4060(200011)23:11<759:MCITTM>2.0.ZU;2-M
Abstract
All musculature examined in the tiny, 0.3-mm, marine Antarctic mite Halacar ellus thomasi (i.e. body and appendages) appeared ultrastructurally to be o f the transversely striated type with continuous Z-lines. Tubules of sarcop lasmic reticulum lay among the myofibrils. The complexity of the sarcotubul ar system, sarcomere lengths of over 6 mu m, and the abundance of mitochond ria are interpreted as signs that the mite is slow moving, but capable of c onsiderable and sustained contraction forces, features deemed necessary in the strong currents of the frigid water prevailing in the mite's habitat. P resence and distribution of regulatory (troponin, tropomyosin, caldesmon an d calponin), contractile (actin, myosin, paramyosin and miniparamyosin) and structural (alpha-actinin, titin, minititin and nebulin) proteins were det ermined immunocytochemically. The results are consistent with the notion of a well-functioning contractile machinery but, furthermore, provide evidenc e for the great importance of the structural proteins alpha-actinin, miniti tin and nebulin in maintaining muscle-cell stability under the environmenta l conditions in which the mite has to function.