LITTLE BODIES BASAL

From Big Medical Encyclopedia

LITTLE BODIES BASAL (synonym: kinetosomes, basal bodies or grains) — the structures located under a cell membrane at the basis of cilia or flagellums, which are taking part in their education and being a part of organoids of the movement of a cell. At eukariotny organisms (see). T. represent the complicated centrioles (see the Cell) and consist of 9 triplets of longitudinal microtubules to dia. 15 — 20 nanometers located around axis T. (fig. 1,2). Internal and average tubules of a triplet proceed in peripheral complexes of microtubules;



the outside tubule comes to an end in a basal (terminal) plate 30 nanometers thick, edges are separated by T. from the basis of a kinotsiliya (i.e. from cilia or flagellums). Internal tubules of triplets are combined by system microfilament with each other, and also with the central capsule located in proximal part T. Therefore on cross section at this level T. remind a wheel with spokes. In the center T. there passes the longitudinal channel to dia. apprx. 6 nanometers, providing, apparently, delivery by the distal end of a kinotsiliya of proteinaceous monomers and lengthening with such way of microtubules. At bacteria of T. contain only one microtubule.

Fig. 1. Diagrammatic representation of a structure of a basal little body: and — longitudinal section (I — the basis of a kinotsiliya, II - a distal part of a basal little body, III — a proximal part of a basal little body); — cross sections at appropriate levels; 1 — a basal (terminal) plate; 2 — triplets of microtubules; 3 — the central channel; 4 — the central capsule; 5 — structure in the form of a wheel.
Fig. 2. The diffraction pattern of cross section of a basal little body at the level of its proximal part: 1 — triplets of microtubules; 2 — microfilaments; 3 — the central capsule; X 5000.

From the basis of T. in a number of cells the thin fibrilla representing roots of ki-notsiliya departs. In ciliary cells of vertebrata this fibrilla forms the filamentous cone turned by top to a kernel. At nek-ry infusorians of T. are connected among themselves by bunches filament. Existence of similar bonds and molecules ATP as a part of T. points to their important role in power promotion and coordination of the movement of kinotsiliya.

Except cilia and flagellums, from T. touch structures can develop (e.g., hairs of receptor cells and photoreceptors of a number of invertebrates, outside joints of sticks and flasks of a retina of an eye of vertebrata, etc.).

Development of T. it is, as a rule, connected with centrioles (see. Cell ). In particular, in spermatozoa of mammals in T. the distal (affiliated) centriole of a dpplosoma turns. In cells of a ciliary epithelium of T. develop from fibrogranulyarny material («a form of condensation»), skoplyayushchegosya in an apical part of a cell around a centriole. The affiliated pro-centrioles separating from this weight are built ranks under a plasma membrane of a cell, creating thus basal little bodies.

S T. blepharoplasts of the elementary and nek-ry vegetable organisms, and also kinetoplasta of flagellates are closely connected (see). Sometimes the term «blepharoplast» is applied even as a synonym of T.

See also Flagellums bacterial .



Bibliography: Velsh U. and Shtorkh F, Introduction to cytology and histology of animals, the lane with it., page 37, M., 1976; D e P about e r t and with E., Novinsky V. and With and e with F. Cytobiology, the lane with English, page 412, M., 1973; M e c of l of e r D. Biokhimiya, Chemical changes in living cell, the lane with English, t. 1, page 37, M., 1980; F p e y - In and with with l and N of A. Sravnitelnaya body a llografiya of cytoplasm, the lane with English, page 94, M., 1976.


Ya. E. Hesinonim

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