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At least 253 records · Page 14Linked to original sources
PubMed1997

Displacement of gold marker in immunoelectron microscopy of human respiratory cilia.

Preembedding immunogold electron microscopy was performed to evaluate the position of outer arm dynein heavy chains in normal human respiratory cilia. Anti-dynein antibody (AD2), which is specific for sea urchin sperm flagellar dynein heavy chains, was used as primary antibody. Direct cross-sections of cilia were selected, and the distance between the center of a cilium and the center of a colloidal gold particle attached to the cilium (X) was measured. The distance between the center of a cilium and the farthest edge of an outer dynein arm of the cilium was measured by ordinary electron microscopy (Yo) and by immunoelectron microscopy (Yi). X was significantly longer than Yo and Yi. If it is assumed that the structure of respiratory cilia is dense and that antibodies are located at the outer side of the actual position of the heavy chains, then the average distance difference of approximately 90-120 A may represent the length of two conjugated antibodies. This length should be kept in mind when performing immunoelectron microscopy. The data suggest that AD2 recognizes the outer arm dynein heavy chains of normal human respiratory cilia.

Adult↗
PubMed1996

Selective incorporation of architectural proteins into terminally differentiated molluscan gill cilia.

Incubation of excised gills from the bay scallop Aequipecten irradians with 3H-leucine demonstrates that many ciliary structural proteins can attain a degree of labeling approaching that previously reported for sea urchin or surf clam embryos undergoing ciliary turnover or regeneration. This labeling is not a consequence of any predominant incorporation into new cilia at the meristematic growth tips of the gill since tissue regions of varying maturity incorporate label into the same proteins at similar levels, with the most mature region having the highest incorporation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorographic analysis of isolated cilia, separated into detergent-soluble membrane/matrix and detergent-insoluble 9+2 axoneme fractions, reveals that 1) tubulin in the membrane/matrix fraction is labeled whereas tubulin in the axoneme is not; 2) no labeled dynein heavy chains are seen in either fraction; 3) the most heavily labeled axonemal components do not appear to any significant extent in the membrane/matrix fraction; and 4) after thermal depolymerization of the microtubules, nearly all labeled proteins reside in the in-soluble ninefold ciliary remnant, the most prominent being tektin A, an integral component of outer doublet microtubules. Further fractionation of the remnant with sarkosyl-urea to produce tektin filaments demonstrates two solubility classes of tekin A, only the more soluble of which is labeled. Very similar selective architectural protein labeling patterns have been reported for steady-state cilia of sea urchin embryos, and this may indicate a widespread turnover or exchange mechanism characteristic of cilia heretofore considered static.

Animals↗
PubMed2001

Cilia propel the embryo in the right direction.

Cilia have long been suspected to play a role in the determination of left-right asymmetry. Humans with the dominantly inherited condition Kartagener syndrome have defective cilia and a 50% incidence of mirror-image positioning of their organs (situs inversus). Analysis of mouse mutations affecting ciliary biogenesis and motility has demonstrated that the molecular motors kinesin and dynein are required to establish normal handed organismal asymmetry. The cilia that propel formation of the embryonic left-right axis are not conventional cilia, but monocilia. They are found on the node, or organizer, of the gastrulation-stage mouse embryo where they drive net leftward movement of the fluid surrounding the node, and initiate left-right asymmetry.

Animals↗
PubMed1980

Primary cilia of the corneal endothelium.

A primary cilium is a normal component of every rabbit corneal endothelial cell, rather than being a rare or sporadic organelle, as previously believed. In common with other cilia of this type it possesses an axonemal organization of 9 +0 which converts distally to 8 + 1; it occurs only one per cell; and the basal body is accompanied by a proximal centriole. Additional structures associated with the basal body are nine transitional fibers, four striated satellite arms, and several rootlets. Ladderlike structures extend between the two centrioles to form the wall of a barrel. Reexamination of primary cilia from other tissues indicates that the ultrastructure of endothelial cilia may be characteristic of primary cilia in general.

Animals↗
PubMed1978

Cilia of neonatal articular chondrocytes: incidence and morphology.

Cilia in neonatal canine articular chondrocytes were studied using morphometric techniques and transmission electron microscopy. The cilia in chondrocytes were morphologically similar to cilia in a variety of other cell types. A chondrocytic cilium consisted of a basal body and a ciliary shaft. The cylindrical basal body was 0.21 micron (S.D. = 0.01 micron) in diameter, 0.50 micron (S.D. = 0.03 micron) in length and contained nine microtubular triplets. The ciliary shaft was 0.196 micron (S.D. = 0.02 micron) in diameter and 1.76 micron (S.D. = 0.80 micron) in length. The number of microbtubular doublets in the ciliary shaft varied depending on where along the length of the shaft the section was taken. This study demonstrates that on the average the frequency of cilia in neonatal articular chondrocytes, as estimated sterologically, was about one cilium per cell.

Animals↗
PubMed1980

Incidence and morphology of equine and murine chondrocytic cilia.

The incidence and structure of equine and murine chondrocytic cilia were studied using serial sections and transmission electron microscopy. Overall, 96% of all equine chondrocytes and 100% of all murine chondrocytes had one cilium. The structure of these cilia included rootlets, basal feet, alar sheets, and an axoneme of nine peripheral doublets which progressively bent and terminated as they coursed towards the tip of the ciliary shaft. Together with the previous studies on neonatal and adult canine chondrocytic cilia, we conclude that the structure and incidence of chondrocytic cilia does not vary among species, regions within a joint, cell types, or age groups.

Animals↗
PubMed2005

An electro-optic monitor of the behavior of Chlamydomonas reinhardtii cilia.

The unicellular green alga Chlamydomonas reinhardtii steers through water with a pair of cilia (eukaryotic flagella). Long-term observation of the beating of its cilia with controlled stimulation is improving our understanding of how a cell responds to sensory inputs. Here we describe how to record ciliary motion continuously for long periods. We also report experiments on the network of intracellular signaling that connects the environment inputs with response outputs. Local spatial changes in ciliary response on the time scale of the underlying biochemical dynamics are observed. Near-infrared light monitors the cells held by a micropipette. This condition is tolerated well for hours, not interfering with ciliary beating or sensory transduction. A computer integrates the light stimulation of the eye of Chlamydomonas with the ciliary motion making possible long-term correlations. Measures of ciliary responses include the beating frequency, stroke velocity, and stroke duration of each cilium, and the relative phase of the cis and trans cilia. The stationarity and dependence of the system on light intensity was investigated. About 150,000,000 total beat cycles and up to 8 h on one cell have been recorded. Each beat cycle is resolved so that each asynchronous beat is detected. Responses extend only a few hundred milliseconds, but there is a persistence of momentary changes that last much longer. Interestingly, we see a response that is linear with absolute light intensity as well as different kinds of response that are clearly nonlinear, implying two signaling pathways from the cell body to the cilia.

Animals↗
PubMed1985

Analysis of the morphology and function of primary cilia in connective tissues: a cellular cybernetic probe?

More than 300 primary cilia have been identified electronmicroscopically in a variety of embryonic and mature connective tissue cells. To further define the enigmatic function of these cilia, we examined the interrelationships between the basal apparatus and cytoplasmic organelles and the ciliary shaft and the extracellular matrix. The basal diplosome was consistently associated with the secretory organelles including the maturing face of the Golgi complex, Golgi vacuoles and vesicles, the microtubular network, the plasma membrane, and coated pits and vesicles. Small vesicles and amorphous granules were also observed within the ciliary lumen and adjacent to the ciliary membrane. Microtubule-membrane bridges linked axonemal tubules to the ciliary membrane. The position, projection, and orientation of the axoneme were influenced by the structural organisation and mechanical properties of the matrix and frequently caused angulation of the ciliary shaft relative to the basal body. Located midway between the secretory apparatus and the extracellular matrix, primary cilia would appear ideally situated to mediate the necessary interaction between the cell and its surrounding environment prerequisite to the formation and maintenance of a functionally effective matrix. We propose that primary cilia in connective tissue cells could act as multifunctional, cellular cybernetic probes, receiving, transducing, and conducting a variety of extrinsic stimuli to the intracellular organelles responsible for effecting the appropriate homeostatic feedback response to changes in the extracellular micro-environment.

Animals↗
PubMed2005

Cilia in the head of hornets: form and function.

In the head of the Oriental hornet, beneath the cuticle, there are plaques of hair cells. These are distributed throughout the upper front part of the head; to wit: in the region of the vertex (i.e., around and behind the ocelli), in the genae around and behind the compound eyes (the ommatidia), and in the region of the forehead or frons. These hair cells are arranged with their thin whip-like part (i.e., cilia) directed outward and morphologically fall into three distinct groups: type (a) thin elongated cilia connected to each other alongside by side-links; type (b) thin elongated cilia of which two or more interconnect at their distal ends via a delicate nerve fiber bearing a knob at its center; and type (c) shorter and thicker cilia that roughly resemble a triangular thorn and are also interconnected by a thin thread, which, however, bears a ball rather then a knob at its center. The knob in the one case and the ball in the other vary in their diameter, but in both instances the interconnecting elements, be they nerve fibers or threads, are seemingly multidirectional. Beneath the frons, in the region of the coronal suture, the hair cells (cilial plaques) are inwardly directed and bear a large trachea at their center. Presumably, the "weighted" cilial cells that are directed toward the exterior of the body aid the hornet in navigation and gravity determination whereas the inwardly directed ciliary cells may possibly serve in acoustic communication. Another element worthy of mention within the hair cells are yellow granules (yg). These yg's originate from the whip-like portion of the ciliary cells that are distributed beneath the frons plate, and also in the yellow stripes of the gastral cuticle. Conceivably, these yellow granules, in both cases, may play a role in the absorption and storage of solar energy. In summary, ciliary structures are involved in the hornet in gravity sensing, in acoustical communication and in light sensing, i.e., with some similarity with what happens in vertebrates in the inner ear and in the photoreceptor.

Animals↗
PubMed1994

Serial repetition of cilia pairs along the tail surface of an ascidian larva.

Regularly spaced cilia pairs were found in two rows immediately opposite to each other mid-dorsally and mid-ventrally along the larval tail surface of the ascidian protochordate Ciona intestinalis. There were approximately ten such equidistantly placed dorsal-ventral sets embedded in the matrix of the extracellular larval test which forms the flattened vertical tail fin. These immotile cilia originate from pairs of cell bodies in mid-dorsal and mid-ventral peripheral nerves running beneath the tail epidermis. The cilia and neural cell bodies were visualized by immunocytochemical staining with anti-tubulin antibodies; their nature was confirmed by ultrastructural examination. This pattern of cilia and neural cell body placement is conceivably related to the segmentation found in vertebrates.

Animals↗
PubMed1978

Effects of topical nasal decongestants on the cilia of a chicken embryo tracheal organ culture system.

There is little physiologic data concerning the possible toxicity of nasal decongestants on respiratory cilia. Consequently, a chicken embryo tracheal organ culture system was employed to study the effect on ciliary activity of various preparations and concentrations of the following medications: tetrahydrozoline hydrochloride (Tyzine), xylometazoline hydrochloride (Otrivin), Dristan, Sinex, NTZ oxymetazoline hydrochloride (Afrin), naphazoline hydrochloride (Privine), and phenylephrine (Neosynephrine). Only two dilutions of injectable phenylephrine 0.25% and 0.10% produced essentially no ciliotoxicity when compared to the cilia in control cultures. All the other topical nasal medications in the concentrations tested possessed some toxicity for cilia. The use of these medications should be tempered with the warning of possible cilia damage.

Animals↗
PubMed2005

Localization of transient receptor potential ion channels in primary and motile cilia of the female murine reproductive organs.

We have examined the subcellular localization of transient receptor potential (TRP) ion channels and the potential sensory role of cilia in murine female reproductive organs using confocal laser scanning microscopy analysis on ovary and oviduct tissue sections as well as on primary cultures of follicular granulosa cells. We show that the Ca2+ permeable cation channel, polycystin-2, as well as polycystin-1, a receptor that forms a functional protein complex with polycystin 2, distinctively localize to primary cilia emerging from granulosa cells of antral follicles in vivo and in vitro. Both polycystins are localized to motile oviduct cilia and this localization is greatly increased upon ovulatory gonadotropic stimulation. Further, the Ca2+ permeable cation channel, TRP vaniloid 4 (TRPV4), localizes to a sub-population of motile cilia on the epithelial cells of the ampulla and isthmus with high intensity in proximal invaginations of the epithelial folds. These observations are the first to demonstrate ciliary localization of TRP ion channels and their possible receptor function in the female reproductive organs. We suggest that polycystins 1 and 2 play an important role in granulosa cell differentiation and in development and maturation of ovarian follicles. In the oviduct both TRPV4 and polycystins could be important in relaying physiochemical changes in the oviduct upon ovulation.

Animals↗
PubMed1982

Paddle cilia (discocilia) in chemosensitive structures of the gastropod mollusk Pleurobranchaea californica.

Scanning electron microscopy of various regions of the body of the marine gastropod Pleurobranchaea californica (McFarland) has revealed a characteristic cell type that bears cilia with dilated discoid-shaped tips. The tips of the cilia consist of an expansion of the ciliary membrane around a looped distal extension of the axoneme. These kinocilia have been observed in numerous other marine invertebrates and are generally referred to as paddle cilia (Tamarin et al. 1974) or discocilia (Heimler 1978). Although many functions have been proposed for paddle cilia, little empirical evidence supports any of the proposals. In Pleurobranchaea we have found that the distribution of this ciliated cell type corresponds exactly to areas of the body known from behavioral studies (Lee et al. 1974; Davis and Matera 1981) to mediate chemoreception. Transmission electron microscopy of the epithelium lining the rhinophores and tentacles of Pleurobranchaea revealed details of the ultrastructure of these ciliated cells and showed that they are primary receptors. These ciliated receptors lie in a yellow-brown pseudostratified columnar epithelium that superficially resembles the olfactory mucosa of vertebrates.

Animals↗
PubMed1980

Qualitative and quantitative freeze-fracture studies on olfactory and nasal respiratory epithelial surfaces of frog, ox, rat, and dog. II. Cell apices, cilia, and microvilli.

The densities and diameters of intramembranous particles in olfactory and nasal respiratory structures of frog, ox, rat and dog have been compared using the freeze-fracture technique. Dendritic endings and the various segments of the cilia of the olfactory receptor cells of a given species have identical particle densities (700--1,800 particles/micrometers2 in P- and 100--600 in E-faces). Densities in P-faces of respiratory cilia are about 1/3 of those in the olfactory cilia. E-face particle densities of these respiratory cilia are often higher than P-face densities. Microvillus P-face densities range from 700--2,000 (respiratory cell microvilli) to 1,800--3,400 particles/micrometers2 (olfactory supporting and Bowman's gland microvilli). Microvillus E-faces show no conspicuous mutual differences. Literature comparisons showed that odour concentrations at threshold are considerably lower (10(5)--10(10) times) than the concentrations of olfactory receptor ending intramembranous particles (5 microM--30 microM) expressed in the same units. Relative differences in particle distributions of the various cell structures studied are usually species-independent. Absolute values vary considerably with the species. Relative P-face particle densities of the supporting cell microvilli tend to correlate with those of dendritic ending structures. Particle diameters are usually similar to corresponding structures and fracture faces in the four species. Apical structures of supporting and Bowman's gland cells in rat and dog show rod-shaped particle aggregates in the P- and pits in their E-faces. Neither sex-dependency nor an influence related to physiological treatments on the particle distributions could be demonstrated.

Animals↗
PubMed1978

Non-ependymal cilia in the habenulae and the interpeduncular nucleus of the frog tadpole.

Cilia of the 9 + 2 pattern are found electron microscopically in nonependymal cells of the habenulae and the interpeduncular nucleus of the tadpole of Rana esculenta at an early stage of development (8 mm length, head to tip of tail). A comparison is made between these and the ependymal and sensory cilia in the same specimens. The cilia project into the neuropil emerging from a perikaryon rich in free ribosomes and displaying a prominent Golgi apparatus. These perikarya contain dense core vesicles. Synapses with vesicles of the clear spherical type have been observed along the ciliary shaft. On a purely morphologic basis the authors hypothesize that these cilia, at least in this early ontogenetic stage, may extend considerably the conducting surface of the cell and represent a sensory structure which could be stimulated by terminal processes belonging to distantly located cells. In addition, they could also be involved in the trophic exchange of material with the adjacent structures.

Animals↗
PubMed1977

Primary 9 + 0 cilia in the embryonic and the adult human heart.

Primary 9 + 0 cilia have been found in the embryonic and the adult human heart. Proximally the cilia show the typical 9 + 0 filament arrangement. Rearrangement of the filaments occur in their distal regions. The cilia are usually found in deep invaginations of the cell membrane, but can also be found in a superficial position. Close connections are frequently found between cilia and thin cytoplasmic extensions from neighbouring cells.

Adult↗
PubMed1976

Abnormal cilia in the bronchial mucosa. Case reports of non-smoking women with bronchogenic carcinomas and an experimental model in guinea-pigs.

Atypical cilia in the bronchial mucosa of non-smoking women and in guinea-pig lungs were studied by the electron microscope. In human cases, numerous compound cilia were observed in the main bronchi. The largest one contained about 40 axial filament complexes in a ciliary shaft. Occasionally, atypical basal bodies were also seen. In the experimental model in guniea-pigs, 50% oxygen at one atmospheric pressure damaged the bronchial surface and resulted in degeneration and reduction of cilia and pellicular structures. The injury was not sufficiently severe to initiate adaptation and reparative mechanisms in the bronchial mucosa, and rapid renewal of the surface structures was found. The human cases were associated with bronchogenic carcinoma but the experimental model suggested that atypical cilia were not always related to pulmonary carcinogenesis.

Animals↗
PubMed1988

Structure and motility of primary cilia in the follicular epithelium of the human thyroid.

In order to clarify contradictory reports concerning ciliary structure and function, follicular epithelium from macroscopically normal portions of 37 surgical specimens of human thyroid were processed for video-microscopy and/or transmission electron microscopy. The cilia of living cells were immotile. In transverse sections the cilia revealed a 9 + 0 pattern at the base of the shaft, whereas towards the distal end the number of microtubular doublets diminished. Dynein arms, radial spokes and central microtubules were absent. The immotility and structure of these primary cilia implies that their function is not related to motility. The phylogenetic and ontogenetic development of the thyroid suggests that tumor cells of follicular origin displaying abnormal secondary cilia may represent a pathological variant of differentiation.

Adenocarcinoma↗