Showing papers on "Ciliogenesis published in 1988"
TL;DR: The different steps of ciliogenesis occurring in quail oviduct were compared to the ciliogenic pattern described in other metazoan species.
96 citations
TL;DR: Results suggest that basal body migration may be driven by the directed assembly of attached actin filaments in the basal cytoplasm.
Abstract: Differentiation of macrociliary cells on regenerating lips of the ctenophore Beroe was studied by transmission electron microscopy. In this study of early development, we found that basal bodies for macrocilia arise by an acentriolar pathway near the nucleus and Golgi apparatus, in close association with plaques of dense fibrogranular bodies. Procentrioles are often aligned side-by-side in double layers with the cartwheel ends facing outward toward the surrounding plaques of dense granules. Newly formed basal bodies then disband from groups and develop a long striated rootlet at one end. At the same time, an array of microfilaments arises in the basal cytoplasm. The microfilaments are arranged in parallel strands oriented toward the cell surface. The basal body-rootlet units are transported to the apical surface in close association with the assembling actin filament bundle. Microfilaments run parallel to and alongside the striated rootlets, to which they often appear attached. Basal body-rootlet units migrate at the heads of trails of microfilaments, as if they are pushed upwards by elongation of their attached actin filaments. Near the apical surface the actin bundle curves and runs below the cell membrane. Newly arrived basal body-rootlets tilt upwards out of the microfilament bundle to contact the cell membrane and initiate ciliogenesis. The basal bodies tilt parallel to the flat sides of the rootlets, and away from the direction in which the basal feet point. The actin bundle continues to enlarge during ciliogenesis. These results suggest that basal body migration may be driven by the directed assembly of attached actin filaments.
44 citations
TL;DR: The polarized, asymmetrical growth of axonemes on the two sides of the macrocilium illustrates a remarkable control of microtubule elongation at the subcellular level and is a consequence of selective fusion of the distal regions of originally separate ciliary membranes.
Abstract: Two patterns of macrociliary growth occur in Beroe. Early differentiation described previously (Tamm & Tamm, 1988) leads to the first pattern of ciliogenesis. A tuft of 10-20 single cilia initially grows out from basal bodies that have migrated to the cell surface and are axially aligned. Ciliary membranes then begin to fuse along their length, except at the base, resulting in thicker groups of cilia on each cell. Progressive fusion of ciliary membranes, together with addition and elongation of new axonemes, finally results in mature macrocilia, 5 microns thick and 40 microns long, enclosed by a single membrane distally. The second pattern of ciliogenesis begins with the simultaneous appearance of several hundred ciliary buds on the apical surface. The short cilia possess individual membranes with bulbous tips, and are not axially aligned. Subsequent elongation is accompanied by progressive fusion of neighbouring ciliary membranes, except at the base, leading to flat-topped 'stumps' surrounded by a single membrane distally. Further elongation then proceeds asymmetrically within each stump. Axonemes on the aboral side of the macrocilium stop elongating, while those towards the oral side increase progressively in height, resulting in a slanted profile. Basal feet and central-pair microtubules are now uniformly aligned. Unequal elongation of axonemes on the oral and aboral sides of the macrocilium continues until the macrocilium resembles a lobster's claw, with a long slender shaft projecting from a broad base. Finally, the polarity of unequal growth reverses: the shorter axonemes on the aboral side elongate and almost catch up with the longer ones on the opposite side, resulting in a mature macrocilium of uniform diameter. The unusual membrane architecture of the macrocilium is thus a consequence of selective fusion of the distal regions of originally separate ciliary membranes. The polarized, asymmetrical growth of axonemes on the two sides of the macrocilium illustrates a remarkable control of microtubule elongation at the subcellular level.
38 citations
TL;DR: Serial ultrathin sections were used to study the formation of the primary cilium and the centriolar apparatus, basal body, and centriole in the neuroepithelial primordial cell of the embryonic nervous system in the mouse, suggesting that in the primordial cells of the embryos nervous system, centriologenesis and ciliogenesis are 2 independent phenomena.
31 citations
TL;DR: Bronchial biopsies were taken during bronchoscopy from five asthmatics before and after oral steroid treatment, and ciliogenesis was abundant in all patients.
Abstract: The effect of steroids on the ciliogenesis of bronchial epithelium has not previously been studied in asthmatics. Bronchial biopsies were taken during bronchoscopy from five asthmatics before and after oral steroid treatment, and studied by transmission electron microscopy. Two untreated healthy subjects served as controls. After treatment ciliogenesis was abundant in all patients.
17 citations
TL;DR: The morphological findings identified in the case material are in agreement with those observed in the developing respiratory epithelium of other higher mammals.
Abstract: Segmental imaging studies of the respiratory epithelium from human embryos and fetuses of normal karyotype have demonstrated that ciliogenesis and ciliation of the respiratory epithelium starts at 7 weeks of gestation. Ciliated cell differentiation follows a pre-determined pattern of distribution. It starts exclusively in the upper segment of the membranous trachea and spreads distally. Ciliation of the carinal angle takes place at 8 weeks of gestation. Three patterns of basal body formation were identified. The various morphological features encountered are described and compared with those observed in cases of Immotile Cilia Syndrome and other pathological conditions. Ciliation of the respiratory epithelium in the cartilaginous trachea does not take place until after the 12th week of gestation. The morphological findings identified in our case material are in agreement with those observed in the developing respiratory epithelium of other higher mammals.
16 citations
TL;DR: Observations indicate the importance of translational regulation during cleavage, transcriptional regulation during ciliogenesis, and regulation of mRNA stability by the level of unpolymerized tubulin during later development.
15 citations
TL;DR: This report describes the ultrastructural alterations observed in the nasal and bronchial mucosa of an 11‐yr‐old male suffering from immotile cilia syndrome (ICS).
12 citations
TL;DR: In this article, necklaces of primary and secondary cilia of olfactory receptor cells and ciliated respiratory cells were studied as a function of embryonic age, and compared with other systems, they showed that primary cilia resemble flagella of eukaryotic flagellates and spermatozoa of some invertebrates with respect to their number of necklace strands.
Abstract: Many cilium types have at their proximal base a particulated membrane structure, the so-called ciliary necklace. Necklaces of primary and secondary cilia of olfactory receptor cells and ciliated respiratory cells, and of primary cilia of olfactory supporting cells were studied as a function of embryonic age. Strand numbers in necklaces of primary cilia of these cell types do not differ, but they differ significantly from those of necklaces of secondary cilia. Primary cilia have 2 to 4, but most commonly 3, necklace strands. This is true for necklaces of primary cilia of 8 different nasal cell types: olfactory epithelial basal and glandular cells, vomeronasal receptor and supporting cells, and microvillous respiratory epithelial cells, in addition to the 3 cell types mentioned above. Comparison with other systems suggests that primary cilia resemble flagella of eukaryotic flagellates and spermatozoa of some invertebrates with respect to their number of necklace strands. Average numbers of necklace strands in secondary olfactory cilia increase from 3-4 at the 16th and 17th gestational days to 6-7 in adults. Those in secondary respiratory cilia increase from 2-3 at the 18th and 19th gestational days to 5-6 in adults. Longer cilia have more strands than shorter ones. Necklaces often have free strand endings, also in primary cilia, suggesting that they spiral. Comparing the present data with those in the literature suggests that necklace features occurring during reciliation differ from those of de novo ciliogenesis. Primary and secondary cilia share the following qualities: 1) Membrane regions above necklace strands can differ quite drastically from those below the strands.(ABSTRACT TRUNCATED AT 250 WORDS)
9 citations