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At least 19 recordsLinked to original sources

PubMed1995

Immunohistochemical analysis of rat and human respiratory cilia with anti-dynein antibody: comparison between normal cilia and pathological cilia in primary ciliary dyskinesia.

Wistar Imamichi rat and human respiratory cilia were examined with anti-dynein antibody (AD2), which is specific for sea urchin sperm flagellar dynein. AD2-labelled fresh-frozen normal rat and human cilia stained clearly by immunofluorescence and the peroxidase-antiperoxidase (PAP) technique. On immunoelectron microscopy, AD2 labelled the outer dynein arms of normal human cilia. Paraffin-embedded normal human cilia also stained by immunofluorescence, although not always clearly. Neither the cilia of WIC-Hyd male rats, an animal model of Kartagener's syndrome, nor human cilia from patients with primary ciliary dyskinesia (PCD) reacted positively by the immunofluorescence or PAP technique. Western blots of normal rat cilia yielded a single band of about 450 kDa. In conclusion, AD2 recognizes the outer arm dynein heavy chains of healthy cilia and may be useful in diagnosing and classifying PCD light microscopically especially when only paraffin-embedded specimens are available. This approach may be of potential use for better defining and classifying PCD.

Adolescent↗

PubMed1998

Computation of the internal forces in cilia: application to ciliary motion, the effects of viscosity, and cilia interactions.

This paper presents a simple and reasonable method for generating a phenomenological model of the internal mechanism of cilia. The model uses a relatively small number of parameters whose values can be obtained by fitting to ciliary beat shapes. Here, we use beat patterns observed in Paramecium. The forces that generate these beats are computed and fit to a simple functional form called the "engine." This engine is incorporated into a recently developed hydrodynamic model that accounts for interactions between neighboring cilia and between the cilia and the surface from which they emerge. The model results are compared to data on ciliary beat patterns of Paramecium obtained under conditions where the beats are two-dimensional. Many essential features of the motion, including several properties that are not built in explicitly, are shown to be captured. In particular, the model displays a realistic change in beat pattern and frequency in response to increased viscosity and to the presence of neighboring cilia in configurations such as rows of cilia and two-dimensional arrays of cilia. We found that when two adjacent model cilia start beating at different phases they become synchronized within several beat periods, as observed in experiments where two flagella are brought into close proximity. Furthermore, examination of various multiciliary configurations shows that an approximately antiplectic wave pattern evolves autonomously. This modeling evidence supports earlier conjectures that metachronism may occur, at least partially, as a self-organized phenomenon due to hydrodynamic interactions between neighboring cilia.

Animals↗

PubMed2003

RPGR isoforms in photoreceptor connecting cilia and the transitional zone of motile cilia.

PURPOSE: The retinitis pigmentosa guanosine triphosphatase (GTPase) regulator (RPGR) is essential for photoreceptor survival. There is as yet no consensus concerning the subcellular localization of RPGR. This study was undertaken as a comprehensive effort to resolve current controversies. METHODS: RPGR in mice and other mammalian species was examined by immunofluorescence. RPGR variants were distinguished by using isoform-specific antibodies. Different tissue processing procedures were evaluated. Immunoblot analysis of serial cross-sections of photoreceptors was performed as a complementary approach to subcellular localization. RESULTS: RPGR was found in the connecting cilia of rods and cones with no evidence for species-dependent variation. RPGR ORF15 was the predominant variant in photoreceptor connecting cilia whereas constitutive RPGR (default) was the sole variant in the transitional zone of motile cilia in airway epithelia. Removal of soluble materials in the interphotoreceptor matrix facilitated detection of RPGR in the connecting cilia in photoreceptors. CONCLUSIONS: RPGR localizes in photoreceptor connecting cilia and in a homologous structure, the transitional zone of motile cilia. These data are important for understanding the multitude of clinical manifestations associated with mutations in RPGR. Interphotoreceptor matrix surrounding the connecting cilia is a key variable for in situ detection of a protein in the connecting cilia.

Animals↗

PubMed2005

Primary cilia of inv/inv mouse renal epithelial cells sense physiological fluid flow: bending of primary cilia and Ca2+ influx.

Primary cilia are hypothesized to act as a mechanical sensor to detect renal tubular fluid flow. Anomalous structure of primary cilia and/or impairment of increases in intracellular Ca2+ concentration in response to fluid flow are thought to result in renal cyst formation in conditional kif3a knockout, Tg737 and pkd1/pkd2 mutant mice. The mutant inv/inv mouse develops multiple renal cysts like kif3a, Tg737 and pkd1/pkd2 mutants. Inv proteins have been shown to be localized in the renal primary cilia, but response of inv/inv cilia to fluid stress has not been examined. In the present study, we examined the mechanical response of primary cilia to physiological fluid flow using a video microscope, as well as intracellular Ca2+ increases in renal epithelial cells from normal and inv/inv mice in response to flow stress. Percentages of ciliated cells and the length of primary cilia were not significantly different between primary renal cell cultures from normal and inv/inv mutant mice. Localization of inv protein was restricted to the base of primary cilia even under flow stress. Inv/inv mutant cells had similar bending mechanics of primary cilia in response to physiological fluid flow compared to normal cells. Furthermore, no difference was found in intracellular Ca2+ increases in response to physiological fluid flow between normal and inv/inv mutant cells. Our present study suggests that the function of the inv protein is distinct from polaris (the Tg737 gene product), polycystins (pkd1 and pkd2 gene products).

Animals↗

PubMed1982

Regulation of ciliary pattern in Dileptus (Ciliata). I. Sensory cilia and their conversion into locomotor cilia.

The surface of Dileptus contains three different regions: locomotor, oral and sensory. Each region has cilia with a specific structure and arranged in a characteristic pattern. In the morphogenetic situation when a sensory region transforms into a locomotor one, sensory cilia undergo structural changes converting them into locomotor cilia. The evidence for this is that cilia are found in the transforming region with an inner microtubular pattern intermediate between that of sensory and locomotor cilia. There are also changes in distribution of sensory units leading to a pattern characteristic of locomotor cilia. The conversion of sensory cilia into locomotor ones is also confirmed by a complete lack of evidence for resorption of sensory units within the transforming region, although the resorption is usually very easily observed with the transmission electron microscope. Transformation lasts about 5 h after the operation; afterwards locomotor cilia of normal appearance occupy the transformed region. This way of regulation of ciliary pattern has not been previously described. Its most surprising feature is the regulation of inner structure in an already differentiated ciliary unit. Some aspects of mechanisms which could control this kind of pattern regulation, are discussed.

Animals↗

PubMed1987

Primary cilia cycle in PtK1 cells: effects of colcemid and taxol on cilia formation and resorption.

The effects of colcemid (0.16-1.0 microM) and taxol (10 microM) on the primary cilia cycle in PtK1 cells were studied by antitubulin immunofluorescence microscopy and by high-voltage electron microscopy of serial 0.25-micron sections. Although these drugs induce a fully characteristic rearrangement (taxol) or disassembly (colcemid) of cytoplasmic microtubules, neither affects the structure of primary cilia formed prior to the treatment or the resorption of primary cilia during the initial stages of mitosis. Cells arrested in mitosis by taxol or colcemid remain in mitosis for 5-7 h at 37 degrees C and then form 4N "micronucleated" restitution nuclei. Formation of primary cilia in these micronucleated cells is blocked by colcemid in a concentration-dependent fashion: normal cilia with expanded (ie, bulbed) distal ends form at the lower (0.16-0.25 microM) concentrations, while both cilia formation and centriole replication are inhibited at the higher (greater than or equal to 1.0 microM) concentrations. However, even in the presence of 1.0 microM colcemid, existing centrioles acquire the appendages characteristically associated with ciliating centrioles and attach to the dorsal cell surface. Continuous treatment with colcemid thus produces a population of cells enriched for the early stages of primary cilia formation. Micronucleated cells formed from a continuous taxol treatment contain two normal centriole pairs, and one or both parenting centrioles possess a primary cilium. Taxol, which has been reported to stabilize microtubules in vitro, does not inhibit the cell-cycle-dependent assembly and disassembly of axonemal microtubules in vivo.

Alkaloids↗

PubMed1986

Alignment of cilia in immotile-cilia syndrome.

Alignment of cilia in nasal epithelial cells from eight human subjects suffering from immotile-cilia syndrome was compared with that of cells from five control subjects. Individual cilia were assessed according to the orientation of their basal feet. The range of orientation of basal feet on a single cell varied from 26 degrees to 261 degrees and 54 degrees to 275 degrees in controls and patients respectively. Less than 10% of the cells from each group supported cilia that were aligned randomly. Alignment was worse in subjects with immotile-cilia syndrome but this could well have been due to secondary characteristics of the disease, such as common viral infection. Very accurate alignment of mucus-propelling cilia may be unnecessary. Measurements from control subjects and some invertebrates suggest that ranges of 140 degrees are common and do not seriously impair mucus propulsion.

Cilia↗

PubMed2004

Decoding cilia function: defining specialized genes required for compartmentalized cilia biogenesis.

The evolution of the ancestral eukaryotic flagellum is an example of a cellular organelle that became dispensable in some modern eukaryotes while remaining an essential motile and sensory apparatus in others. To help define the repertoire of specialized proteins needed for the formation and function of cilia, we used comparative genomics to analyze the genomes of organisms with prototypical cilia, modified cilia, or no cilia and identified approximately 200 genes that are absent in the genomes of nonciliated eukaryotes but are conserved in ciliated organisms. Importantly, over 80% of the known ancestral proteins involved in cilia function are included in this small collection. Using Drosophila as a model system, we then characterized a novel family of proteins (OSEGs: outer segment) essential for ciliogenesis. We show that osegs encode components of a specialized transport pathway unique to the cilia compartment and are related to prototypical intracellular transport proteins.

Animals↗

PubMed1991

Ultrastructure of respiratory cilia of WIC-Hyd male rats. An animal model for human immotile cilia syndrome.

The WIC-Hyd rat is a mutant from the Csk: Wistar-Imamichi rat, with spontaneous hydrocephalus. In male rats, the hydrocephalus is severe and about one half of hydrocephalic male littermates possess situs inversus totalis. Ependymal cilia in these animals are immotile, and this defect is regarded as a mechanical cause of hydrocephalus. This paper presents the ultrastructural features of respiratory cilia in these rats in comparison with those in human immotile cilia syndrome. The respiratory cilia in these rats also are immotile and the dynein arms are missing, as in human cases. Previously only eight dogs with immotile cilia syndrome and a mutant hydrocephalic-polydactyl mouse were reported with respect to these phenomena. However the WIC-Hyd rat is the first useful animal model for human immotile cilia syndrome, and further studies may serve to clarify the genetic background of this condition.

Animals↗

PubMed1981

An ultrastructural study of primary cilia, abnormal cilia and ciliary knobs from the ciliated cells of the guinea-pig trachea.

Single primary cilia are found in developing as well as mature ciliated cells of guinea-pig tracheal epithelium. A few biciliated cells were observed, and in a rare case one cell had developed four such processes. Primary cilia are characterized by a 9 + 0 microtubular arrangement near the base, while a transition to an 8 + 1 pattern occurs at a slightly more distal position. Spokes are lacking, and dynein arms are absent or incompletely developed. The function, if any, of primary cilia remains unknown. In the population of the motile 9 + 2 cilia atypical forms are very rare, i.e. less than 0.1%. Of the various abnormalities cilia with supernumary microtubules are most common. Only one atypical basal body was observed. Although some of the aberrant forms undoubtedly are non-motile, their very low number suggests that they have no practical influence on the muco-ciliary clearance. Local extrusions of the ciliary membrane, here named ciliary knobs, are believed to be fixation artefacts. It is suggested that they represent circumscribed regions of the ciliary membrane which are sensitive to changes in the environmental osmotic pressure.

Animals↗

PubMed2006

Nephrocystin specifically localizes to the transition zone of renal and respiratory cilia and photoreceptor connecting cilia.

Nephronophthisis (NPHP) is a hereditary cystic kidney disorder that causes renal failure in children and young adults and can be associated with various extrarenal disorders, including retinitis pigmentosa. Six NPHP genes, whose functions are disrupted by autosomal recessive mutations in patients with NPHP, have been identified. The majority of patients with NPHP carry homozygous deletions of NPHP1 encoding nephrocystin. Previous data indicate that nephrocystin forms a complex at cell junctions and focal adhesions. Here, it is shown that nephrocystin specifically localizes at the ciliary base to the transition zone of renal and respiratory cilia and to photoreceptor connecting cilia. During in vitro ciliogenesis of primary human respiratory epithelial cells, nephrocystin can be detected first with a diffuse cytoplasmic localization as soon as cell polarization starts, and translocates to the transition zone when cilia are formed. In columnar respiratory cells, nephrocystin is attached tightly to the axonemal structure of the transition zone at a region that contains the calcium-sensitive cilia autotomy site. In patients with homozygous NPHP1 deletions, nephrocystin is absent from the entire respiratory cell, including the transition zone, which might be of interest for future diagnostic approaches. Cilia formation is not altered in primary nephrocystin-deficient respiratory cells, which is consistent with previous findings obtained for the Caenorhabditis elegans ortholog. In addition, it is shown that the localization pattern of intraflagellar transport proteins and nephrocystin differs, suggesting distinct functional roles. In conclusion, nephrocystin deficiency or dysfunction at the transition zone of renal monocilia and the photoreceptor connecting cilium might explain renal failure and retinal degeneration that are observed in patients with NPHP1.

Adaptor Proteins, Signal Transducing↗

PubMed1980

The dyskinetic cilia syndrome. Ciliary motility in immotile cilia syndrome.

Ciliary motility was studied in three patients with Kartagener syndrome who had previously been found to have absent nasal and pulmonary mucociliary transport and missing dynein arms in nasal cilia. A video system was used to record movement of cilia obtained by nasal brushings for analysis of wave form and beat frequency. Two patterns of abnormal ciliary beat were observed; an oscillating and a rotating type of motion. There was no evidence of planar coordination of metachronicity. This abnormal motion was present in up to 40 percent of cells and the remainder were totally immotile. Thus, in Kartagener syndrome many ciliated cells are motile, but the motion is abnormal. We suggest that "immotile cilia syndrome" is a misnomer, and recommended it be renamed "dyskinetic cilia syndrome."

Adenosine Triphosphatases↗

PubMed1984

[How useful is the ultrastructural study of the cilia of the respiratory tract in the diagnosis of an immotile cilia syndrome?].

The immotile cilia syndrome (ICS) comprises a range of congenital defects of the ciliary apparatus most probably transmitted by autosomal recessive inheritance. Because cilia occur mainly in the respiratory and genital tract, the clinical symptoms of ICS are most commonly chronic sinusitis, bronchitis, bronchiectasis and male sterility. The syndrome can be associated with a situs inversus and is then called Kartagener's syndrome. We studied the ciliary ultrastructure in airway biopsies of 5 patients suffering from chronic upper and lower respiratory tract infections. With the single exception of one female patient with confirmed ICS diagnosis (Kartagener's syndrome) the etiology of the recurrent infections was unknown. The following ciliary defects were observed: missing dynein arms, radial spoke defects, missing nexin links, microtubular transpositions, compound cilia, supernumerary, absent, or incomplete microtubules, lack of ciliary orientation and various abnormal patterns of microtubular arrangement. In no instance did a patient show only a single anomaly; defects were always combined. Missing dynein arms, radial spoke defects and microtubular transpositions have frequently been described as lesions specific for ICS. Whenever these lesions were found simultaneously in both the respiratory and genital tracts, their genetic origin cannot be doubted. In our confirmed ICS patient the outer dynein arms were not missing but were reduced in number and length in a large number of cilia. The biopsy was, however, obtained from the heavily infected maxillary sinus and it is known that inflammation can lead to a loss of dynein arms. In the light of our investigations and of a review of the published cases of ciliary anomalies, it is concluded that none of the above defects in itself is specific for ICS. They may all occur as secondary lesions or sporadically as varieties in otherwise healthy subjects. It therefore appears questionable whether ICS can be diagnosed from the ciliary ultrastructure of a single airway biopsy. Assessment of ICS cannot be based simply on the ultrastructural demonstration of a particular ciliary defect, but necessitates additional considerations particularly regarding the origin of the biopsy, the sampling procedures and quantitation of defects. It appears necessary to investigate samples from different parts of the airways and quantitatively analyze the prominent lesions.

Abnormalities, Multiple↗

PubMed1978

Paddle cilia and discocilia - genuine structures? Observations on cilia of sensory cells in marine turbellaria.

Kinocilia of epidermal sensory cells in fixed marine Turbellaria often terminate as flattened biconcave discs. The distal part of the ciliary axoneme curves back upon itself forming a 360 degree loop which is enveloped by the plasmalemma. In living animals this structure can be induced by the addition of sodium cacodylate, monobasic sodium phosphate, dibasic sodium phosphate, sucrose, calcium chloride, or formaldehyde to the sea water. Specimens treated with sodium chloride, glutaraldehyde, or osmium tetroxide do not show modified cilia. In animals prepared for EM at low temperature and with a buffered hypotonic fixative less kinocilia are modified than in animals treated with a buffered iso- or hypertonic fixative and at a higher temperature. It is assumed that the unusually shaped cilia, described as "paddle cilia" or "discocilia" in other invertebrates, do not represent a genuine but an artificial structure.

Animals↗

PubMed1979

Kinetics of the regeneration of sea-urchin cilia. II. Regeneration of animalized cilia.

The kinetics of the regeneration of cilia of Arbacia punctulata animalized by treatment with trypsin have been examined. The cilia regenerate with biphasic kinetics: an initial linear phase which changes abruptly to a second, slower linear rate. Inhibition of protein synthesis with 10 microM emetine has little effect on the first phase but totally abolishes the second, suggesting that the first phase represents the utilization of a pre-existing precursor pool while the second reflects de novo protein synthesis. However, cilia will regenerate again following a second deciliation in the presence of emetine, to half the plateau value of the first regeneration, indicating that only a fraction of the pool of the limiting precursor can be assembled into the regenerating cilium. It is proposed that a residual pool of this precursor is required to maintain the assembly-disassembly equilibrium in favour of the assembled organelle.

Animals↗

PubMed1996

Reflection of structural abnormality in the axoneme of respiratory cilia in the clinical features of immotile cilia syndrome.

In immotile cilia syndrome (ICS), respiratory symptoms show a wide range of severity. Various types of axonemal abnormalities related to ICS are known, but it is unclear whether the symptom severity is related to the type of abnormality. We sent a questionnaire concerning respiratory symptoms to ICS patients. Another type of the questionnaire regarding the clinical features and axonemal abnormality of ICS was sent to the physicians in charge. Analysis of the results showed that in the 48 patients responding, those lacking outer dynein arms (LO) in cilia were more likely to be associated with situs inversus (SI) than those lacking inner dynein arms (LI). Sputum symptoms were more serious in those associated with SI than those unassociated with SI, as was the case in those associated with LO compared to those with LI. Based on these results, it may be concluded that the type of dynein arm defect in cilia is related to the clinical features in ICS.

Adolescent↗

PubMed1989

[Immotile cilia syndrome--ultrastructural deviations of the nasal cilia].

This study deals with a transmission electron microscopic examination of the nose cilia. Dyskinetic or dysfunctional cilia result clinically in the immotile-cilia syndrome. Differentiation between congenital and acquired anomalies is important. An early diagnosis as part of the therapeutic approach should be considered.

Cilia↗

PubMed1983

Supernumerary microtubules in the cilia of two siblings causing "immotile cilia syndrome".

The function and ultrastructure of nasal cilia in 2 siblings with unexplained chronic sinusitis and bronchitis were investigated. Both patients lacked nasal mucociliary clearance (greater than 30 min). On electron microscopy, the ultrastructure of nasal cilia showed an extra doublet or supernumerary microtubules with disorganized microtubular network. Other axonemal components were normally present. It is conceivable that an "extra" component of the axoneme may be added to those "defects" already recognized as a cause of the "immotile-cilia syndrome".

Adolescent↗