Macrocilia with numerous shafts from the lips of the ctenophore Beroe
Date
1965-05-18
Authors
Horridge, George Adrian
Journal Title
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Publisher
Royal Society
Abstract
The maerocilia are 6 to 10 /xm thick and 50 to 60 jam long. Each consists of 2000 to 3000
shafts, of the typical 9 + 2 pattern, which are arranged in a hexagonal array within a single
membrane. The whole macrocilium beats like a single cilium, inward with reference to the
mouth, and with antiplectic metachronal waves. Isolated macrocilia, when cut off, oscillate
in one plane by a symmetrical bending movement at the middle. Cross-connexions lie
between nearby fibrils of adjacent shafts in three different planes, and are apparently strong
and permanent. The fibrils, each consisting of a pair of tubules, are numbered with these
bridges as reference points. A system of tubules spreads between the basal bodies. Hoot
structures are little developed. In bent cilia there is no buckling of shafts and the diameter
of the shafts is the same on the concave as on the convex side. Therefore an active sliding
mechanism between fibrils 2, 3, 4 (and between fibrils 6, 7, 8), rather than a contractile one,
is postulated as the source of movement. This theory may apply to all cilia, and is an
example of how this unique giant cilium may be utilized for the analysis of the function of
the components of the 9 + 2 pattern during active movement.
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Keywords
maerocilia, cilia, shaft
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Source
Proceedings of the Royal Society of London B: Biological Sciences
Type
Journal article
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2037-12-31
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