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At least 199 records · Page 11Linked to original sources
PubMed1988

Single modified cilia displayed by cells of human internal stratified epithelia (oral cavity, vagina).

Serial sections of human vaginal and keratinized oral-gingival epithelia were investigated for ciliary structures. Most melanocytes of the gingival epithelium lacked cilia, whereas almost all basal keratinocytes of the deeper portion of the epithelial ridges possessed one cilium each. In the suprabasal layers of the ridges only a few keratinocytes exhibited a single cilium. In the basal layer, at the top of the connective tissue papillae, approximately every second keratinocyte displayed a single cilium. In the suprabasal layers above the ridges no ciliated keratinocytes were observed. The basal cells of the vaginal epithelium were endowed with cilia, while cilia were absent from the suprabasal cells. In the human forearm epidermis most melanocytes and keratinocytes are supplied with a single cilium; it has been suggested that they may play a role in light reception. However, the widespread occurrence of 9 + 0 cilia in epithelial cells of internal epithelia and their coincidence with the sites of renewal of keratinocytes suggests that a relationship may exist between solitary cilia and mitotic activity.

Adult↗
PubMed1989

Cilia on bovine mammary epithelium: ultrastructural observations.

Ultrastructural examination of bovine mammary tissues revealed the presence of 9+0 or primary cilia protruding from surfaces of alveolar epithelial and myoepithelial cells. Cilia of epithelial cells protruded approximately 1200 nm into lumina of alveoli and arose from a basal body centriole, the associated centriole of the diplosome, and an accessory rootlet system. Cilia on epithelial cells were more frequently observed than cilia on myoepithelial cells. Occasional cilia made contact with macrophages in the alveolar lumen. The structures were more commonly found in tissues from nonlactating cows, and most were observed in the ventral portion of the mammary gland.

Animals↗
PubMed1977

Substructure of solitary cilia in mouse kidney.

Recent scanning electron microscopic studies confirm the presence of solitary cilia on most epithelial cells along the mammalian nephron and collecting ducts. By transmission electron microscopy we have found that the axonemata of such cilia consist of a maximal number of 9 doublet and no singlet filaments. 10% of the cross-sectioned cilia contain 9 doublets arranged in peripheral ring (9 + 0 pattern). 30% of the cross-sections contain 8 or 7 doublets in peripheral ring and 1 or 2 doublets in the central region (8 + 1 and 7 + 2 patterns). Serial sections and goniometer tilt reveal the central doublets to originate as dislodged peripheral doublets. 60% of the sectioned cilia contain filament numbers between 8 and 4. In patterns of 5 and 4 filaments single microtubules predominate. The functional significance of these atypical cilia is discussed.

Animals↗
PubMed1986

A method for measuring the orientation ("beat direction") of respiratory cilia.

We have created a method for measuring the orientation of cilia in the respiratory epithelium. Ciliary orientation is the direction perpendicular to the plane defined by the central tubules of the cilia and is an estimate of ciliary beat direction. Ciliary orientation can be estimated by measuring the angle between the plane defined by the central tubules and a reference line. The standard deviation of these measurements describes the variation present in the beat directions of the cilia. The reference line must be so chosen that the majority of measurements falls at about the middle of the 0 degree-180 degrees range. We tested measurements by using both a glass angle measure and a semiautomatic image analyzer (IBAS I). The latter approach was faster and more reproducible. We made our measurements of normal tissues on samples obtained from two healthy adult non-smokers. Measurements were made in four areas of each sample, with 59-110 cilia in each. The differences between the maximum and minimum angles of the ciliary orientation in the same area varied from 167.9 degrees to 85.4 degrees from the reference line. The standard deviation varied from 18.0 degrees to 35.4 degrees and we consider this to be a normal variation in ciliary orientation. Of the cilia, 57% were within a standard deviation of 20 degrees.

Adult↗
PubMed1985

Cyclic AMP and calcium in the differential control of Mytilus gill cilia.

Lateral (L) cilia of Mytilus gill are activated by serotonin which, in molluscan systems, is known to activate adenylate cyclase. Triton-extracted models of L-cells, arrested at greater than 10(-6) M Ca++, are stimulated to beat by the addition of 10(-5) M cAMP while still under Ca++ arrest conditions, suggesting that cAMP-activation is not mediated by alterations of Ca++ levels. Using isolated, permeabilized cilia, we find, independent of [Ca++], that cAMP-dependent protein phosphorylation in L-cilia occurs uniquely and reversibly on three low molecular weight polypeptides of 23,000, 18,000, and 14,000 daltons. Phosphorylation is maximal at cAMP concentrations above 0.5 microM. The phosphorylated chains partially co-extract at high salt with a 14S dynein fraction and have approximately the same molecular weights as reported for dynein light chains. Such conditions mainly extract the outer dynein arm, about 40% of the Mg++-ATPase activity, and a corresponding amount of the cAMP phosphorylated chains. However, the three polypeptides sediment together at 10-11S, clearly separable from the 14S dynein ATPase. Using a gel-overlay technique, we find that calmodulin binds to axonemal polypeptides of L-cilia with molecular weights of 18,000 and 13,000, independent of Ca++, while in mixed-population cilia, only a 12,000 dalton chain binds calmodulin, in a Ca++ dependent manner. In neither case are calmodulin binding proteins found in the high salt fraction containing the cAMP-dependent phosphorylated chains, indicating that, in spite of some similarity in molecular weight, the cAMP-phosphorylated and calmodulin binding polypeptides are different. Also, double-labelling indicates that only the 18,000 dalton chains co-migrate.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Endothelial cilia in human aortic atherosclerotic lesions.

"Primary" cilia were present in the endothelial cells of human aortic fatty dots and streaks but not in those of normal intima. They had the features of cilia of the "9 + 0" axonemal configuration observed in many other cells. A lateral foot process and transitional fibers "anchored" the ciliary basal body in the cytoplasm, but rootlets were not identified in material examine. Ladder-like configurations interconnected the two centrioles (= diplosome) of control endothelium. The "primary" cilia of endothelium differed from those of the rudimentary type observed in smooth muscle cells in similar lesions of man, but shared many features with cilia of those present in experimental atherosclerosis in rabbit. Cilia were rarely described in vascular endothelium. It is believed that, to date, they were not reported to occur in normal or pathological arteries in man. It is being stressed that whereas the significance of these unusual organelles remains uncertain, their widespread occurrence may indicate that their role is more important than was believed previously, and they should cease being a curiosity only.

Aorta↗
PubMed1981

Microtubule-membrane interactions in ctenophore swimming plate cilia.

The cilia in ctenophore swimming plates are organized into long rows and the cilia within each of the rows are connected to one another by interciliary bridges. The interciliary bridges form a type of intracellular junction and are periodically spaced at 15 nm intervals along the long axis of a cilium. The bridges bind adjacent cilia together even after dissolution of the ciliary membrane by non-ionic detergent. Interciliary bridges are attached to the compartmenting lamellae, which are paracrystalline structures composed of spherical particles which are periodically attached to the outer doublet microtubules at the sites to which the microtubule-membrane bridges are bound. It is proposed that the compartmenting lamellae are modifications of the ciliary microtubule-membrane bridge found in other eukaryotic cilia and that it is associated with a junctional complex that binds adjacent cilia together in swimming plates.

Animals↗
PubMed1989

Bovine olfactory cilia preparation: thiol-modulated odorant-sensitive adenylyl cyclase.

We have characterized the adenylyl cyclase activity in a newly developed preparation of isolated olfactory cilia from the bovine chemosensory neuroepithelium. Like its counterparts from frog and rat, the ciliary enzyme was stimulated by guanine nucleotides, by forskolin, and by a variety of odorants in the presence of GTP. The main difference between the bovine olfactory cilia preparation and the frog and rat olfactory cilia preparation is that odorant stimulation of the bovine olfactory adenylyl cyclase is strongly inhibited by submillimolar concentrations of dithiothreitol. This inhibition is a consequence of a concomitant increase in the GTP-stimulated level and the decrease of the odorant stimulation of the enzyme. Nasal respiratory cilia have a much lower level of adenylyl cyclase activity and show no odorant stimulation. Owing to the large quantities of material available, the bovine olfactory cilia preparation is advantageous for studies of the proteins involved in chemosensory transduction.

Adenylyl Cyclases↗
PubMed1994

The orientation of primary cilia during the wound response in 3Y1 cells.

The behavior of the primary cilia of 3Y1 cells in the interphase was investigated by indirect immunofluorescence microscopy and transmission electron microscopy, using an antibody for tubulin. At 4.5 h after scraping a part of a confluent cell sheet, the primary cilia of cells facing the wound were located predominantly forward of the nucleus on the wounded side, and were oriented in the direction of the leading lamellae. Cytoplasmic microtubules (MTs), emanating from around the base of the cilia, were well developed in the leading lamellae on the wounded side. On the other hand, in the cells of an unperturbed area away from the wounded edge, the primary cilia remained randomly distributed near the nucleus. The position and a certain well-defined orientation of a pair of centrioles seem to play an important role for the development of cytoplasmic MTs, and consequently the orientation of the centrioles is controlled by the primary cilia.

Animals↗
PubMed1991

L-alanine binding sites and Na+, K(+)-ATPase in cilia and other membrane fractions from olfactory rosettes of Atlantic salmon.

1. Membrane fractions were obtained from homogenates of olfactory rosettes from Atlantic salmon (Salmo salar) or from isolated olfactory cilia and homogenates of deciliated olfactory rosettes. 2. Specific binding of L-[3H]alanine was saturable, high-affinity, and effectively inhibited by L-threonine, L-serine and L-alanine but not by L-lysine or L-glutamic acid. Comparable results were obtained with L-[3H]serine except for the presence of a second, lower affinity, binding site for L-alanine but not L-serine. 3. Specific binding of L-[3H]alanine was inhibited by low concentrations of mercury ion, acidic pH, and high concentrations of cadmium, copper or zinc ions. Aluminum had no effect. 4. Specific binding sites for L-alanine were present in membranes from isolated cilia at a level 2-fold that of membranes prepared from the deciliated rosette. 5. Ouabain sensitive Na+, K(+)-ATPase activity was also determined in cilia preparations. This enzyme was present in cilia at a level approximately 3-fold that of membranes prepared from the deciliated rosette. 6. The results are consistent with the presence of an olfactory alanine receptor in S. salar with binding characteristics similar to those of a variety of other fish species and with a localization on olfactory cilia as well as non-ciliated receptor cell membranes.

Alanine↗
PubMed1982

Changes in morphology and physiology of olfactory receptor cilia during development.

Ciliated olfactory receptor neurons in vertebrates turn over throughout life. We show that these neurons bear different types of cilia at different developmental stages; cilia on newly differentiating cells are short and motile; cilia on mature cells are longer and immotile; Mg2+ and adenosine 5'-triphosphate are requisite for ciliary motion; stimulation with odorants can induce synchronous motion and that this process is mediated by Ca2+. We propose that receptor neurons have two distinguishable developmental states. In the first, before the growing axon establishes synaptic connection to the brain, the cells bear motile cilia and are generally irritable. In the second, the cilia are long and immotile and the cells can distinguish between odorants.

Animals↗
PubMed2004

Primary cilia in vertebrate corneal endothelial cells.

The presence of primary cilia in corneal endothelial cells of a range of species from six non-mammalian vertebrate classes (Agnatha, Elasmobranchii, Amphibia, Teleostei, Reptilia and Aves) is examined by scanning and transmission electron microscopy. Our aim is to assess whether these non-motile cilia protruding into the anterior chamber of the eye are a consistent phylogenetic feature of the corneal endothelium and if a quantitative comparison of their morphology is able to shed any new light on their function. The length (0.42-3.80 microm) and width (0.12-0.44 microm) of the primary cilia varied but were closely allied with previous studies in mammals. However, interspecific differences such as the presence of a terminal swelling in the Teleostei and Amphibia suggest there are functional differences. Approximately one-third of the endothelial cells possess cilia but the extent of protrusion above the cell surface varies greatly, supporting a dynamic process of retraction and elongation. The absence of primary cilia in primitive vertebrates (Agnatha and Elasmobranchii) that possess other mechanisms to control corneal hydration suggests an osmoregulatory and/or chemosensory function.

Amphibians↗
PubMed2005

Localization of the angiopoietin receptors Tie-1 and Tie-2 on the primary cilia in the female reproductive organs.

Blood vessel homeostasis and endothelial cell survival depend on proper signalling through angiopoietin receptors such as the receptor tyrosine kinases Tie-1 and Tie-2. We have studied the presence and subcellular localization of these receptors in murine female reproductive organs using confocal microscopy analysis of antibody stained tissue sections of ovary and oviduct. We show that Tie-2 principally localizes to primary cilia of the surface epithelium of the ovary, bursa and extra-ovarian rete ducts as well as to plasma membranes of ovarian theca and endothelial cells. Primary cilia of follicular granulosa cells were negative. Further, Tie-1 and Tie-2 localized to motile cilia of the oviduct. Western blotting detection and immunolocalization of anti-Tie-2 in ovary and oviduct were abolished by administration of an anti-Tie-2 blocking peptide, confirming antibody specificity. In a series of immunohistochemical analysis on human ovarian tissues we also observed a unique localization of Tie-2 to the primary cilia of ovarian surface epithelium. These observations are the first to show ciliary localization of angiopoietin receptors. Our results support the hypothesis that cilia of the female reproductive organs play a novel and important sensory role in relaying physiochemical changes from the extracellular environment to epithelial cells of the oviduct, the ovary and extra-ovarian tissues.

Animals↗
PubMed2006

Novel tools to unravel molecular mechanisms in cilia-related disorders.

Cilia are hair-like organelles extending from the cell surface that execute motile (e.g. respiratory cilia) and/or sensory functions (e.g. renal monocilia). The basic ultrastructure of cilia and flagella has been well established by electron microscopy. Several recent reports have now provided intriguing new insights into the complex molecular composition of cilia and flagella. These data from genome, proteome and transcriptome analyses will facilitate the systematic discovery and understanding of genes responsible for human cilia-related diseases, such as primary ciliary dyskinesia, polycystic kidney disease and male sterility.

Animals↗
PubMed2004

Redistribution of the kinesin-II subunit KAP from cilia to nuclei during the mitotic and ciliogenic cycles in sea urchin embryos.

KAP is the non-motor subunit of the heteromeric plus-end directed microtubule (MT) motor protein kinesin-II essential for normal cilia formation. Studies in Chlamydomonas have demonstrated that kinesin-II drives the anterograde intraflagellar transport (IFT) of protein complexes along ciliary axonemes. We used a green fluorescent protein (GFP) chimera of KAP, KAP-GFP, to monitor movements of this kinesin-II subunit in cells of sea urchin blastulae where cilia are retracted and rebuilt with each mitosis. As expected if involved in IFT, KAP-GFP localized to apical cytoplasm, basal bodies, and cilia and became concentrated on basal bodies of newly forming cilia. Surprisingly, after ciliary retraction early in mitosis, KAP-GFP moved into nuclei before nuclear envelope breakdown, was again present in nuclei after nuclear envelope reformation, and only decreased in nuclei as ciliogenesis reinitiated. Nuclear transport of KAP-GFP could be due to a putative nuclear localization signal and nuclear export signals identified in the sea urchin KAP primary sequence. Our observation of a protein involved in IFT being imported into the nucleus after ciliary retraction and again after nuclear envelope reformation suggests KAP115 may serve as a signal to the nucleus to reinitiate cilia formation during sea urchin development.

Amino Acid Sequence↗
PubMed2005

Functional characterization of the C. elegans nephrocystins NPHP-1 and NPHP-4 and their role in cilia and male sensory behaviors.

Autosomal dominant polycystic kidney disease (ADPKD) and nephronophthisis (NPH) share two common features: cystic kidneys and ciliary localized gene products. Mutation in either the PKD1 or PKD2 gene accounts for 95% of all ADPKD cases. Mutation in one of four genes (NPHP1-4) results in nephronophthisis. The NPHP1, NPHP2, PKD1, and PKD2 protein products (nephrocystin-1, nephrocystin-2 or inversin, polycystin-1, and polycystin-2, respectively) localize to primary cilia of renal epithelia. However, the relationship between the nephrocystins and polycystins, if any, is unknown. In the nematode Caenorhabditis elegans, the LOV-1 and PKD-2 polycystins localize to male-specific sensory cilia and are required for male mating behaviors. To test the hypothesis that ADPKD and NPH cysts arise from a common defect in cilia, we characterized the C. elegans homologs of NPHP1 and NPHP4. C. elegans nphp-1 and nphp-4 are expressed in a subset of sensory neurons. GFP-tagged NPHP-1 and NPHP-4 proteins localize to ciliated sensory endings of dendrites and colocalize with PKD-2 in male-specific sensory cilia. The cilia of nphp-1(ok500) and nphp-4(tm925) mutants are intact. nphp-1; nphp-4 double, but not single, mutant males are response defective. We propose that NPHP-1 and NPHP-4 proteins play important and redundant roles in facilitating ciliary sensory signal transduction.

Alleles↗
PubMed2003

Identification of CHE-13, a novel intraflagellar transport protein required for cilia formation.

Cilia are present on cells of many eukaryotic organisms and recent data in the mouse suggest that ciliary defects can cause severe developmental abnormalities and disease. Studies across eukaryotic systems indicate that cilia are constructed and maintained through a highly conserved process termed intraflagellar transport (IFT), for which many of the proteins involved have yet to be identified. IFT describes the movement of large protein particles consisting of an A and a B complex along the cilia axoneme in anterograde and retrograde directions. Herein we describe a novel C. elegans gene, F59C6.7/9, that is required for cilia assembly and whose function is disrupted in che-13 ciliogenic mutants. As previously shown for all IFT complex B genes identified to date, expression of che-13 (F59C6.7/9) is regulated by the RFX-type transcription factor DAF-19, suggesting a conserved transcriptional pathway in ciliogenesis. Fluorescent-tagged CHE-13 protein concentrates at the base of cilia and moves along the axoneme as expected for an IFT protein. Furthermore, loss of che-13 differentially affects the localization of two known IFT complex B proteins, OSM-5 and OSM-6, implying that CHE-13 functions as part of this complex. Overall, our data confirm that CHE-13 is an IFT protein and further that the IFT particle assembles in an ordered process through specific protein-protein interactions.

Amino Acid Motifs↗
PubMed1991

Complex choristoma of the eyelid containing ectopic cilia and lacrimal gland.

A 2-year-old girl was born with an aggregate of ectopic cilia in the right upper eyelid that intermittently produced tears. During elective excision, the cilia were found to be clustered tightly with prominent bulb-like follicles. A separate lobe of lacrimal gland tissue was adjacent to the roots of the cilia just posterior to the orbital septum with no direct communication with the lacrimal gland. Histopathologically, the lesion contained multiple large hair follicles in the dermis with accompanying adnexal structures. Large ectopic lobules of lacrimal gland tissue also were present. Postoperatively, the child had a good cosmetic result and has remained asymptomatic over an 18-month follow-up period. To our knowledge, this is the first reported case of an eyelid choristoma containing ectopic cilia and lacrimal gland. Ectopic cilia alone is a very rare anomaly of the lashes, with only nine cases reported in the literature.

Child, Preschool↗