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At least 631 records · Page 35Linked to original sources
PubMed1988

Isolation and reactivation of highly-coupled newt lung cilia.

The paired lungs of the newt, Taricha granulosa, are simple, unbranched sacs, 3.5-5.0 cm in length. The inner epithelium overlying the pulmonary vein is differentiated into a mucociliary tract that extends the entire length of the lung. Populations of single, demembranated ciliary axonemes, 12-13 micron in length, can be isolated by extracting whole lungs or primary cultures of the ciliated epithelium with Triton X-100. The motile capabilities of the isolated axonemes are the highest yet obtained for any ciliary model. When exposed to a suitable reactivating medium containing Mg2+ and ATP, nearly 100% of the axonemes become motile. Uniform reactivation of high quality requires short extraction times, minimization of mechanical damage, and strict adherence to optimal conditions throughout the extraction, storage, and reactivation procedures. Significant deviations from either pH 7.0 or 0.12 M salt can lead to a rapid, irreversible decrease in the beat frequency of reactivated axonemes. Both DTT and EDTA serve to stabilize their motility. The isolated axonemes beat at 29.5 Hz in the presence of 1.75 mM ATP at 21 degrees C, matching the beat frequencies measured for cultured cells at the same temperature. With 5 mM ATP, beat frequencies over 40 Hz are measured. Our results show that neither the plasma membrane, accessory structures, nor hydrodynamic coupling of cilia are required for this activity and imply that the lack of these factors is not responsible for the low motile capabilities of ciliary models isolated previously.

Adenosine Triphosphate↗
PubMed1995

Protein substrates for cGMP-dependent protein phosphorylation in cilia of wild type and atalanta mutants of Paramecium.

In the ciliated protozoan Paramecium, swimming direction is regulated by voltage-gated Ca2+ channels in the ciliary membrane. In response to depolarizing stimuli, intraciliary Ca2+ rises, triggering reversal of the ciliary power stroke and backward swimming. One class of Ca(2+)-unresponsive behavioral mutants of Paramecium, atalanta mutants, cannot swim backward even though they have functional Ca2+ channels in their ciliary membrane. Several atalanta mutants were characterized with regard to several Ca(2+)-dependent activities, but no significant difference between wild type and the mutants was detected. However, one allelic group, atalanta A (initially characterized by Hinrichsen and Kung [1984: Genet. Res. Camb. 43:11-20]), showed a helical swimming path of opposite handedness from that of wild-type cells when detergent-permeabilized cells ("models") were reactivated with MgATP. When cGMP-dependent protein kinase purified from wild-type cells was added to atalanta A models, the handedness of the swimming path was reversed. Cyclic GMP stimulated in vitro phosphorylation of several proteins in isolated cilia, and the pattern of phosphoproteins was very similar for wild type and atalanta mutants, with one exception: a protein of 59 kDa was phosphorylated much less in the mutant ata A. When ciliary proteins were separated by gel electrophoresis and then phosphorylated "on blot" by purified cGMP-dependent protein kinase, phosphoprotein patterns were similar in wild type and ata mutants except that a 48 kDa protein (p48) from ata A3 was more heavily phosphorylated. This difference in p48 phosphorylation was also observed with cGMP-dependent protein kinase purified from ata A3 mutant cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Outer arm dynein from Newt lung respiratory cilia: purification and polypeptide composition.

Dyneins are multimeric ATPases that comprise the inner and outer arms of cilia and flagella. It previously has been shown that salt extraction of newt lung axonemes selectively removes > 95% of the outer arm dynein (OAD), and that the beat frequency of OAD-depleted axonemes cannot be activated as compared to controls [Hard et al., 1992: Cell Motil. Cytoskeleton 21:199-209]. Therefore, expression of the activated state appears to require the presence of outer dynein arms. The present study was undertaken to ascertain basic information on the structure and molecular composition of newt OAD. Populations of demembranated axonemes were extracted with 0.375 M salt. Each lung released approximately 1.4 x 10(7) axonemes during isolation, yielding approximately 120 ng of salt extractable OAD. Electron microscopy of negatively stained samples revealed that newt OAD consisted of two globular heads joined together by a Y-shaped stem, similar to sea urchin and trout sperm OAD. Each head appeared to be roughly spherical in shape, measuring approximately 17 nm in diameter. Electrophoretic analysis of whole axonemes revealed more than six dynein heavy chains when resolved in silver stained 0-8 M urea, 3-5% acrylamide gradients. Extracted OAD, either crude in high salt or purified by alloaffinity, was composed of two heavy chains. UV-induced (366 nm) photolytic cleavage at the V1 site, performed in the presence of Mg2+, vanadate, and ATP, produced four new polypeptides (M(r) 234, 232, 197, and 189 kD). Photolysis was supported by Mg2+ and Ca2+, but did not occur in the presence of Mn2+. The apparent M(r) of the dynein heavy chains was determined to lie between 430-420 kD. Eight discrete polypeptides (putative intermediate chains, IC1-IC8, M(r), 175-56 kD) copurified with the alpha- and beta-heavy chains by microtubule-alloaffinity. Based on its extraction characteristics, polypeptide composition in purified and crude samples, and structure, we conclude that this two-headed particle represents the entire newt respiratory outer arm dynein.

Amino Acid Sequence↗
PubMed1990

Rapid activation of alternative second messenger pathways in olfactory cilia from rats by different odorants.

The molecular mechanisms mediating the chemo-electrical signal transduction in olfactory receptor cells are still elusive. In this study odor induced formation of second messengers in rat olfactory cilia was monitored in a subsecond time range using a rapid kinetic device. Application of micromolar concentration of citralva induced a rapid, transient elevation of the cyclic adenosine monophosphate level, whereas the concentration of inositol trisphosphate was not affected. In contrast, pyrazine caused a rise in the concentration of inositol trisphosphate, not affecting the level of cyclic adenosine monophosphate. Analysis of the kinetic parameter for the odorant induced reaction indicated that apparently two systems are operating simultaneously. The activating effects of odorants appear to be mediated via different G-proteins. Thus, at least two different second messenger pathways appear to be involved in olfactory signal transduction.

Animals↗
PubMed1977

Structure and organization of radial spokes in cilia of Tetrahymena pyriformis.

The structure and organization of radial spokes, the principal components between each of the peripheral doublet microtubules and the central sheath which surrounds the central pair of microtubules have been described in Tetrahymena pyriformis cilia. The radial spokes are grouped in triplets and are attached to the A-microtubule of each peripheral doublet at intervals of 200/280/360 A, the 200 A spacing being most distal to the base of the cilium. The radial spoke triplets are organized in the axoneme in a double helix with a pitch of 4,680 A. A method for determining the helical disposition by correcting for doublet sliding is presented.

Animals↗
PubMed1992

Aplasia of respiratory tract cilia.

We report on ciliary aplasia of the respiratory tract, a rare disorder of the mucociliary apparatus, that is insufficiently recognized as a distinct entity. A culture method for ciliogenesis was developed by our laboratory and offers the advantage of studying cilia free of secondary changes associated with infection. Three cases of primary ciliary aplasia were documented histologically in direct biopsy specimens and also in biopsy specimens cultured specifically for ciliogenesis. Primary ciliary aplasia should be differentiated from secondary ciliary aplasia in which basal bodies are present and ciliogenesis takes place in specific culture. Only hereditary ciliary abnormalities are expressed in cell cultures. We critically review the cases of ciliary aplasia reported to date.

Bronchi↗
PubMed2000

CHE-3, a cytosolic dynein heavy chain, is required for sensory cilia structure and function in Caenorhabditis elegans.

Forward genetic screens using novel assays of nematode chemotaxis to soluble compounds identified three independent transposon-insertion mutations in the gene encoding the Caenorhabditis elegans dynein heavy chain (DHC) 1b isoform. These disruptions were mapped and cloned using a newly developed PCR-based transposon display. The mutations were demonstrated to be allelic to the che-3 genetic locus. This isoform of dynein shows temporally and spatially restricted expression in ciliated sensory neurons, and mutants show progressive developmental defects of the chemosensory cilia. These results are consistent with a role for this motor protein in the process of intraflagellar transport; DHC 1b acts in concert with a number of other proteins to establish and maintain the structural integrity of the ciliated sensory endings in C. elegans.

Amino Acid Sequence↗
PubMed1999

The effect of the pneumococcal toxin, pneumolysin on brain ependymal cilia.

Densely ciliated ependymal cells cover the ventricular surface of the brain and cerebral aqueducts separating cerebrospinal fluid, which is infected in meningitis, from neuronal tissue. We have established an ex vivo model that allows measurement of ependymal ciliary beat frequency, using high-speed video analysis, during incubation with bacterial toxins. Ciliated ependyma, from Wistar rats, was exposed to the pneumococcal toxin, pneumolysin, and a mutant form with markedly reduced cytotoxic activity (;0.1%). Wild-type pneumolysin (1500 HU/ml and 150 HU/ml: 10 and 1 microg/ml) caused rapid ciliary stasis (30-150 s), sloughing of cilia and cytoplasmic extrusion. Ciliary slowing before stasis was seen at 15 HU/ml (0.1 microg/ml); however, no effect on ciliary beat frequency was seen at lower concentrations (1.5 HU/ml and 0.15 HU/ml: 0.01 and 0.001 microg/ml). Mutant pneumolysin, 99.9% deficient in haemolytic activity, caused rapid ciliary stasis at 10 microg/ml but no effect was seen at lower concentrations (1-0.1 microg/ml). Pneumolysin, at levels which may be produced during severe pneumococcal meningitis, may cause rapid ependymal ciliary stasis.

Animals↗
PubMed1982

Neutrophil migration and orientation under agarose: findings in patients with the immotile cilia syndrome and effects of cytochalasin B and vinblastine.

This study has shown that the agarose technique is well suited for determination of whether impaired PMN migration is due to defective direction finding of deficient locomotive ability. By assessments of the degree of orientation of neutrophils together with measures of migration distances, we demonstrated that vinblastine treated normal neutrophils and PMNs from patients with the immotile cilia syndrome mainly move in a chemokinetic manner, whereas cytochalasin B hampers locomotive ability, but leaves direction finding intact. Hence, information whether chemotaxis or chemokinesis predominates is easily obtained in one single assay system.

Cell Movement↗
PubMed1994

Histamine and leukotriene C4 effects on in vitro ciliary beat frequency of human upper respiratory cilia.

Decreased mucociliary transport can occur in patients with type I (IgE-mediated) allergic rhinitis or allergic asthma. This study investigated if the allergic mediators histamine and leukotriene C4 (LTC4) could interfere with ciliary beat frequency (CBF) of in vitro human upper respiratory cilia and eventually result in decreased mucociliary transport. Ciliated epithelium of human adenoid tissue was used in the experiments and CBF was determined using a computer-assisted photoelectric method. Histamine in concentrations of 10(-6) - 10(-3) M (n = 12) and LTC4 as 10(-9) - 10(-6) M solutions (n = 10) showed no statistically significant dose-dependent effect on CBF in vitro.

Adenoids↗
PubMed1990

Polyadenylated RNA during DAPI-arrested regeneration of Tetrahymena cilia.

Regeneration of cilia in Tetrahymena cells treated with 1 micrograms/ml of 4',6-diamidino-2-phenylindole (DAPI) takes place about 30 min later then in untreated controls. Analysis of RNA isolated at 50-th min of reciliation, that is when the control cells-but not DAPI-treated ones-have just restored their motility, revealed that; - 1. Two peaks of polyadenylated RNA were present in DAPI-treated cells as well as in the control ones; - 2. The mobility of the polyadenylated RNA was the same in the two compared cell samples; - 3. In wheat germ cell-free translational system these poly (A+)-RNA probably directed the synthesis of alpha- and beta-tubulin; - 4. The amount of polyadenylated RNA in compared cell samples was different, in DAPI-treated Tetrahymena its amount was estimated at 1.43% vs. 1.89% in control ones.

Animals↗
PubMed1992

Basal conductance of frog olfactory cilia.

The conductance of isolated frog olfactory cilia in the absence of odorants and second messengers has been measured. Current flowing through the pipette-membrane seal rather than the ciliary membrane was subtracted. In normal physiological solutions, each cilium has a conductance averaging 92 pS at the neuronal resting potential. This basal conductance allows current to be carried by K+ or Na+ but not by Cl-. In some cases, single channels with a unit conductance of 153 pS were observed. The conductance of the ciliary membrane implies a length constant for electrotonic conduction of about 160 microns. Since the reversal potential of the basal conductance is near the neuronal resting potential, it should help to stabilize the ciliary potential at some cost to stimulus transduction efficiency.

Animals↗
PubMed1983

Abnormal cilia in a male-sterile mutant mouse.

In mice homozygous for the mutation hydrocephalic-polydactyl (hpy) ciliary axonemes from tracheal, oviducal, and ependymal lining cells showed a variety of abnormalities. Defects included: a deficiency of inner dynein arms, extra central tubules, a displacement of one outer doublet and/or the central tubules, and double axonemes. More than one kind of defect was seen in some axonemes. None of the types of defects observed in mutants were encountered in equivalent samples from non-mutant littermates. Except for the most common defect, the deficiency in dynein arms, which occurred to about the same extent (approximately 34%) in all three tissues, there were marked variations in frequency among the tissue types with respect to the other defects. In general, defects such as central tubule anomalies, displaced tubules, and double axonemes occurred with the highest frequencies in axonemes from tracheal epithelial cells and with the lowest frequencies in samples of oviducal epithelium. Fused cilia were seen only in ependymal cell samples. Some of the defects encountered were common to sperm flagella axonemes while others appeared restricted to somatic tissues, suggesting, perhaps, each tissue type may exert its own modulating influence on the expression of the mutant gene.

Animals↗
PubMed1976

The central tubuli in distal segments of olfactory cilia lack dynein arms.

By means of the tannic acid-glutaraldehyde fixation method, the lack of dynein bridges between the central two tubuli in distal segments of mouse olfactory cilia is demonstrated. Consequently, these organelles are supposed to be unable to beat actively, in contrast to the proximal ciliary shafts.

Animals↗
PubMed1987

Dyskinetic cilia syndrome: clinical, radiographic and scintigraphic findings.

The clinical, electron microscopic and radiographic data of 9 patients with dyskinetic cilia syndrome (DCS) are presented. Scintigraphic evaluation of mucociliary dynamics in six patients showed evidence of dyskinesia. Ventilation and perfusion studies were performed to evaluate obstructive lung disease. Retrospectively, bronchiectasis could be detected in 77% of the patients by analysis of the chest radiograph and lung scintigraphy, and bronchography potentially avoided in the seven patients who underwent this procedure.

Biopsy↗
PubMed1998

Molds on house walls and the effect of their chloroform-extractable metabolites on the respiratory cilia movement of one-day-old chicks in vitro.

The ciliostatic activity of the chloroform-extractable endo- and exometabolites of 5 strains of filamentous fungi--Alternaria sp., Aspergillus glaucus group, Aspergillus versicolor, Cladosporium sphoerospermum, Penicillium sp. and Ulocladium sp.--isolated from molded walls of a dwelling--on tracheal cilia from 1-d-old chicks in vitro was evaluated. Endometabolites of Alternaria sp. and A. versicolor and exometabolites of Ulocladium sp. were the most active, these extracts stopped the ciliary movement within 1 d. The results are discussed in relation to the health status of people living in "moldy" dwellings.

Age Factors↗
PubMed1994

Effect of mycotoxins on in vitro movement of tracheal cilia from one-day-old chicks.

The effect of 11 mycotoxins on the ciliary movement of tracheal epithelium from one-day-old chicks in vitro was examined. Sterigmatocystin and diacetoxyscirpenol were most ciliostatically active in vitro; the ciliostatic effect was observed after 2 d if the amount concentration was 30 micrograms/L. In contrast, patulin stopped the movement of cilia after 2 d only if its concentration was 20 mg/L.

Aflatoxins↗