Organized Filaments in the adhesive system of Macrostomum tuba Graff, 1882 ( Platyhelminthes, Macrostomida)
Braz. j. morphol. sci
;
23(3/4): 471-477, July-Dec. 2006. ilus
Article
in English
| LILACS
| ID: lil-644246
ABSTRACT
The adhesive organs or duo-gland adhesive organs of platyhelminths are formed by a specialized epithelialcell and extensions of two gland cells. These organs are used for temporary fixation of the organism tosurfaces in aquatic habitats. The mechanisms involved in adhesion to and release from a given surfacedepend on secretions produced by the glands; less is known about the involvement of cytoplasmic filamentsin the anchoring cell itself. In this study, we examined the structure of the adhesive organs present in thetail plate of Macrostomum tuba Graff, 1882 (Platyhelminthes, Macrostomida), a freshwater, free-livingflatworm. Scanning and transmission electron microscopy allowed elucidation of the three-dimensionalorganization of the adhesive system, especially of the microvilli that formed the outer collar (or papilla),which was endowed with a fibrous core. Electrical stimulation caused the flatworms to extend their papillaeabove the ciliated surface. The use of tannin- and diamine-containing fixatives showed that the filamentousarray contained tonofilaments and actin filaments. Tonofilaments concentrate in the axis of each microvillus;actin filaments, about 7-8 nm thick, spread out towards the periphery. Scanning images demonstrated thefinger-like shape of the papillae, about 7-8 ìm high, with a terminal opening. Microvilli followed a straightcourse along the surface.
Full text:
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Index:
LILACS (Americas)
Main subject:
Platyhelminths
/
Actin Cytoskeleton
/
Actins
Limits:
Animals
Language:
English
Journal:
Braz. j. morphol. sci
Journal subject:
Anatomy
Year:
2006
Type:
Article
Affiliation country:
Brazil
Institution/Affiliation country:
State University of Londrina/BR
/
University of São Paulo/BR
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