Ciliary Beat Pattern Research Articles

The Challenges of Diagnosing Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is a rare genetic disorder of ciliary structure and function. The diagnosis can be challenging, particularly when using nongenetic assays. The "gold standard" diagnostic test is ultrastructural analysis of respiratory cilia obtained by nasal scrape or brush biopsy. A few specialized centers use high-speed videomicroscopy to examine ciliary beat. Certain beat patterns correlate with ultrastructural defects, and, in some cases, subtle alterations in beat pattern can be seen when ultrastructure is normal. Recent studies have shown that nasal nitric oxide (NO) is very low in patients with PCD compared with healthy control subjects; therefore, this assay may be a useful screening or adjunctive test for PCD. Because acute respiratory illnesses may yield alterations in ciliary ultrastructure, ciliary beat, and nasal NO values, these tests should be performed during a stable baseline period. Identification of an array of PCD genes has provided the opportunity for making a definitive genetic diagnosis for PCD in some cases. All of these approaches have a role in diagnosing PCD. For example, PCD has been confirmed by identifying disease-causing mutations in a heavy dynein chain gene in individuals with normal ciliary ultrastructure but subtle defects in ciliary beat and low nasal NO. Priorities to improve nongenetic diagnostic capability include standardization of nasal NO as a screening test and the development of specialized centers using uniform approaches for the analysis of ciliary ultrastructure and ciliary beat pattern. Another chapter in this issue (see Zariwala and colleagues, pp. 430) addresses the progress toward improved capabilities for definitive genetic testing.

Desarrollo y validación de un método de análisis de la movilidad ciliar para el diagnóstico precoz de la discinesia ciliar primaria

BackgroundPrimary ciliary dyskinesia (PCD) is a clinically uniform entity, but cilia motility and structure can vary between patients, making the diagnostic difficult. The aim of this study was to evaluate the sensitivity and specificity in diagnosing PCD of a system of high-resolution digital high-speed video analysis with proprietary software that we developed for analysis of ciliary motility (Desinsoft-Bio 200). The secondary aim was to correlate nasal ciliary activity with clinical and structural abnormalities in PCD. Material and methodsWe analysed nasal mucociliary transport, cilia ultrastructure, nasal ciliary beat frequency and beat pattern studied by high-resolution digital high-speed video in 25 cases of PCD (11 Kartagener syndrome), 27 secondary ciliary dyskinesia and 34 healthy volunteers. ResultsNasal mucociliary transport was defective in both primary and secondary ciliary dyskinesia. Ciliary immotility was observed only in 6 patients with Kartagener syndrome and correlated with the absence of dynein. We observed a correlation between partial dynein deficiencies and ciliary dyskinesia. Cilia activity and structure was normal in secondary ciliary dyskinesia. ConclusionNasal mucociliary transport showed high sensitivity for PCD diagnosis with a low specificity. High-resolution digital high-speed video has a high sensitivity and specificity for diagnosing PCD. This system of video analysis is more useful than ultrastructural study and mucociliary transport for PCD screening. Dynein absence is correlated with cilia immotility and is more common in patients with Kartagener syndrome.

Finding the ciliary beating pattern with optimal efficiency

We introduce a measure for energetic efficiency of biological cilia acting individually or collectively and numerically determine the optimal beating patterns according to this criterion. Maximizing the efficiency of a single cilium leads to curly, often symmetric, and somewhat counterintuitive patterns. However, when looking at a densely ciliated surface, the optimal patterns become remarkably similar to what is observed in microorganisms like Paramecium. The optimal beating pattern then consists of a fast effective stroke and a slow sweeping recovery stroke. Metachronal coordination is essential for efficient pumping and the highest efficiency is achieved with antiplectic waves. Efficiency also increases with an increasing density of cilia up to the point where crowding becomes a problem. We finally relate the pumping efficiency of cilia to the swimming efficiency of a spherical microorganism and show that the experimentally estimated efficiency of Paramecium is surprisingly close to the theoretically possible optimum.

Identification and evolutionary implications of neurotransmitter–ciliary interactions underlying the behavioral response to hypoxia inLymnaea stagnalisembryos

Acceleration of embryonic rotation is a common response to hypoxia among pond snails. It was first characterized in Helisoma trivolvis embryos, which have a pair of sensorimotor neurons that detect hypoxia and release serotonin onto postsynaptic ciliary cells. The objective of the present study was to determine how the hypoxia response is mediated in Lymnaea stagnalis, which differ from H. trivolvis by having both serotonergic and dopaminergic neurons, and morphologically distinct ciliated structures at comparative stages of embryonic development. Time-lapse video recordings of the rotational behavior in L. stagnalis revealed similar rotational features to those previously observed in H. trivolvis, including rotational surges and rotational responses to hypoxia. Serotonin and dopamine increased the rate of rotation with similar potency. In contrast, serotonin was more potent than dopamine in stimulating the ciliary beat frequency of isolated pedal cilia. Isolated apical plate cilia displayed an irregular pattern of ciliary beating that precluded the measurement of ciliary beat frequency. A qualitative assessment of ciliary beating revealed that both serotonin and dopamine were able to stimulate apical plate cilia. The ciliary responses to dopamine were reversible in both pedal and apical plate cilia, whereas the responses to serotonin were only reversible at concentrations below 100 μmol l(-1). Mianserin, a serotonin receptor antagonist, and SKF83566, a dopamine receptor antagonist, effectively blocked the rotational responses to serotonin and dopamine, respectively. The rotational response to hypoxia was only partially blocked by mianserin, but was fully blocked by SKF83566. These data suggest that, despite the ability of serotonin to stimulate ciliary beating in L. stagnalis embryos, the rotational response to hypoxia is primarily mediated by the transient apical catecholaminergic neurons that innervate the ciliated apical plate.

Cooling of Cilia Allows Functional Analysis of the Beat Pattern for Diagnostic Testing

Reports of the effect of low temperatures on ciliary beat frequency (CBF) are conflicting, and the effect on ciliary beat pattern has not been reported. We aimed to clarify this association and determine whether cooling of cilia may allow ciliary function to be assessed without the need of expensive high-speed video microscopy. Fourteen nasal brush biopsy samples were collected, and the CBF and beat pattern of undisrupted ciliated edges were evaluated. Two methods were used to strictly control changes in temperature: One enabled rapid transitory measurements during cooling and warming, and the other was used to maintain accurate low temperatures over longer periods of time. A sigmoid relationship between CBF and temperature was observed. CBF decreased with cooling and increased with warming. Ciliary function was unaffected by the direction of temperature change and was maintained down to 2°C. The percentage of dyskinetic cilia observed at 2°C or 4°C was unchanged from that at 37°C. Contrary to previous research, our data show that cilia continue to beat with a normal pattern at temperatures as low as 2°C. Slowing of cilia by cooling may allow detailed analysis of ciliary beat pattern without the need of expensive high-speed video microscopy.

Muco-ciliary transport: Effect of mucus viscosity, cilia beat frequency and cilia density

In this paper, a two-layer Newtonian fluid model consisting of an upper mucus layer and a lower periciliary layer (PCL) is developed to simulate the muco-ciliary transport process. The objective is to investigate the important factors that may affect the muco-ciliary transport and to understand better the underlying mechanics of some respiratory diseases such as cystic fibrosis. The numerical technique implemented in this study is the projection method combined with the Immersed Boundary Method (IBM) for prescribed ciliary beating patterns. A systematic study of the muco-ciliary transport measured in terms of the mean mucus velocity is performed by changing (i) the viscosity of the mucus, (ii) the cilia beat frequency, (iii) the numbers of cilia, (iv) the thickness of PCL, and (v) the surface tension at the interface between the mucus and PCL. We conclude that the cilia beat frequency, the number of cilia, and the depth of PCL are the critical factors affecting the muco-ciliary transport. Moreover, the present results show that the velocity of mucus layer will be reduced when the length of cilia is larger than the depth of PCL.

Ciliated Air-Liquid Cultures as an Aid to Diagnostic Testing of Primary Ciliary Dyskinesia

The diagnosis of primary ciliary dyskinesia (PCD) can prove difficult because of secondary damage of ciliated tissue. Here we audit culturing cells, obtained by nasal brushing, to a ciliated phenotype using an air-liquid interface method to determine if the effects of secondary damage on cilia were reduced following culture. Of 231 patients consecutively referred for diagnostic testing, culture was attempted in 187, with 101 (54%) becoming ciliated. Of the 90 brush biopsy samples with a low dyskinesia score (< 40%), 71 grew cilia after culture (79% success). Significant secondary damage (> 40% dyskinesia) was present in 69 (43%) of the initial brush biopsy samples, and of these, 18 (26%) became ciliated after culture. In these samples, ciliary dyskinesia was significantly (P < .001) reduced (64% ± 6.8% before culture, 31% ± 4.5% after culture). Ciliary beat frequency (CBF) after cell culture was similar to CBF before culture. Cell culture helped to exclude PCD in eight patients for whom ciliary dyskinesia was present in > 70% of the initial brush biopsy sample, a level at which a rebiopsy would normally be requested. In six patients in whom no cilia were found in the initial brush biopsy samples, ciliated cell culture was successful and excluded the diagnosis. PCD was diagnosed in 28 patients and ciliated cell culture was successful in 12 (43%) showing identical ciliary beat pattern and electron microscopy findings. Ciliary dyskinesia was reduced following cell culture to a ciliated phenotype compared with the initial brush biopsy sample. The specific PCD phenotype was maintained after culture.

Ciliary dysfunction and ultrastructural abnormalities are features of severe asthma

Epithelial dysfunction has been implicated in asthma pathophysiology, but no studies have directly assessed ciliary function in asthma. To study the ciliary function and epithelial ultrastructure of patients with asthma and healthy controls. We studied ciliary beat frequency and beat pattern by using digital high-speed video imaging and ultrastructure by transmission electron microscopy of bronchial epithelial strips from 7 subjects with mild, 7 with moderate, and 19 with severe asthma and 9 healthy controls. The median (interquartile range) ciliary beat frequency was decreased in moderate (6.5 [4.4-8.5] Hz) and severe asthma (6.7 [6.1-7.6] Hz) compared with controls (10.5 [9.7-11.8] Hz; P< .01). Dyskinesia and immotility indices were higher in severe asthma (65% [43%-75%]; 6.3% [1%-9.5%], respectively) compared with controls (4% [0%-6.7%; 0%, respectively; P<.01). These abnormalities were related to disease severity (ciliary beat frequency, r(s)= -0.68; dyskinesia index, r(s)= 0.86; immotility index, r(s)= 0.65; P< .0001). The ultrastructure of the epithelium was abnormal in severe asthma with a reduction in ciliated cells, an increase in dead cells, and ciliary disorientation compared with all other groups (P< .05). Compared with patients with mild asthma and healthy controls, patients with severe asthma showed increased ciliary depletion, microtubular defects, mitochondrial damage, and cytoplasmic blebbing (P<.01). All of these changes were related to disease severity. Ciliary dysfunction and ultrastructural abnormalities are closely related to asthma severity. Ciliary dysfunction is a feature of moderate to severe asthma, and profound ultrastructural abnormalities are restricted to severe disease. Whether these changes contribute to the development of severe asthma phenotype remains to be determined.

NewDNAH11mutations in primary ciliary dyskinesia with normal axonemal ultrastructure: Fig. 1—

To the Editors: In primary ciliary dyskinesia (PCD; Mendelian Inheritance in Man database #242650), a rare genetic disorder, the dysfunctional motility of cilia and impaired mucociliary clearance result in a myriad of clinical manifestations including recurrent infections of the respiratory tract, eventually causing lung damage, such as bronchiectasis, laterality defects and male infertility 1. The heterogeneous clinical presentation of PCD and the limitations of transmission electron microscopy (TEM) to assess ultrastructural defects within the cilium may delay the diagnosis 2. Ciliary beat frequency and pattern analyses and nasal nitric oxide (nNO) measurements are helpful 1, 3, 4, but only ciliogenesis in cultured cells has been reported as decisive for the diagnosis of the atypical PCD phenotype with normal axonemal ultrastructure 1, 5. Under these conditions, the identification of disease-causing mutations could overcome the current diagnostic limitations of TEM and improve our understanding of the biology and function of the cilium 2, 6, 7. For these reasons, we have assessed whether an analysis of the DNAH11 gene, in which some nonsense mutations have been reported to be associated with a normal axonemal ultrastructure but with an abnormal nonflexible beating pattern, reduced cilium bending capacity and a hyperkinetic beat 7, could be used to identify new mutations in three atypical PCD patients and thus be used in the diagnostic work-up of these most difficult cases. We observed three patients (A and B, sister and brother; and C, male), at the ages of 15 yrs and 5 months, 9 yrs and 4 months, and 8 yrs, respectively. The two siblings presented situs inversus. Both patients had chronic respiratory symptoms which required repeated treatment with antibiotics. Patient A also had neonatal purulent rhinitis with frequent relapses, chronic rhinosinusitis and otitis …

Cilia Motility and Structure in Primary and Secondary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is a clinically uniform entity, although cilia motility and structure can vary among patients, making diagnosis difficult. Chronic sinusitis, bronchiectasis, sinus hypoplasia, secretory otitis media, and low fertility are common in PCD patients. The aim of this work was to correlate nasal ciliary activity with clinical and structural abnormalities in PCD. A secondary aim was to evaluate the usefulness of high-resolution digital high-speed video (DHSV) in the diagnosis of PCD. We analyzed nasal mucociliary transport and cilia ultrastructure by electron microscopy and studied nasal ciliary beat frequency (CBF) and beat pattern using high-resolution DHSV imaging in 34 healthy volunteers, 25 individuals with PCD (including 11 with Kartagener's syndrome [KS]with situs inversus), and 27 with secondary ciliary dyskinesia (SCD). Nasal mucociliary transport was defective in the PCD and SCD patients. Ciliary immotility was observed in only six KS patients and was correlated with the absence of dynein. We observed a correlation between partial dynein deficiency and an uncoordinated, stiffly vibrating ciliary beat. Cilia activity and structure were normal in the SCD patients. Nasal mucociliary transport showed a sensitivity of 100% for the diagnosis of PCD but has low specificity. High-resolution DHSV imaging has high sensitivity and specificity for the diagnosis of PCD. Video analysis is probably more useful than the study of mucociliary transport and cilia ultrastructure in screening for PCD. The absence of dynein was correlated with ciliary immotility and was more common in KS patients.

Diagnostic Testing of Patients Suspected of Primary Ciliary Dyskinesia

Electron microscopy (EM) of ciliated epithelium is widely used to diagnose primary ciliary dyskinesia (PCD). Ciliary beat frequency (CBF) has been used to screen samples to determine whether EM is indicated. Beat pattern analysis has been advocated as an additional diagnostic test. Neither has been subject to formal review. To determine the ability of CBF and beat pattern analysis to predict EM-diagnosed PCD. CBF calculation and beat pattern analysis, using high-speed video microscopy, and EM were performed on nasal tissue from 371 patients consecutively referred to the Leicester Royal Infirmary for diagnostic assessment for PCD. With EM as the "gold standard," receiver operating characteristic (ROC) curves were constructed and sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values were calculated for CBF less than 11 Hz, ciliary dyskinesia score equal to or exceeding 2, at least 90% of ciliated edges beating dyskinetically, and an immotility index equal to or exceeding 10%. PCD was excluded in 270 patients and confirmed in 70 by EM. The sensitivity, specificity, PPV, and NPV for CBF less than 11 Hz were 87.1, 77.2, 50.0, and 95.8%, respectively. These values were higher for ciliary dyskinesia scores equal to or exceeding 2 (92.5, 97.6, 91.2, and 98.0%) and when at least 90% of ciliated edges were dyskinetic (97.1, 95.3, 84.6, and 99.2%). ROCs confirmed that the ciliary dyskinesia score and percentage of dyskinetic edges were superior screening indices compared with CBF and the immotility index. The use of CBF alone to screen which biopsies should have EM will result in a significant number of missed diagnoses. Ciliary beat pattern analysis is a more sensitive and specific test for PCD with higher PPV and NPV.

High prevalence of primary ciliary dyskinesia in a British Asian population

Determining the prevalence of primary ciliary dyskinesia (PCD) in different populations has proved difficult, with estimates varying between one in 4000 to one in 40 000. The aim of this...

Disrupted ciliated epithelium shows slower ciliary beat frequency and increased dyskinesia

Ciliary function studies for the diagnosis of primary ciliary dyskinesia (PCD) are usually performed on nasal brush biopsy samples. It is not uncommon to find disrupted epithelial strips of tissue in these samples, and occasionally throughout a sample. The aim of the present study was to determine if cilia on disrupted ciliated epithelial edges beat with a normal pattern and frequency similar to that of cilia on undisrupted edges. Nasal brush biopsy samples from 42 children in whom the diagnosis of PCD was excluded were assessed. The epithelial strips were categorised into five groups: intact undisrupted ciliated epithelial edge, ciliated epithelial edge with minor projections, ciliated epithelial edge with major projections, an isolated ciliated cell on an epithelial edge and single unattached ciliated cells. Ciliary beat frequency and beat pattern of 50 samples from each group were determined using high speed digital video microscopy. The cilia on epithelial edges with varying degrees of disruption showed significantly reduced beat frequency and significantly increased dyskinesia compared with those on intact, undisrupted ciliated epithelial edges. Ideally, the assessment of ciliary beat pattern and frequency for PCD diagnosis should only be performed on undisrupted ciliated edges.

Update in Primary Ciliary Dyskinesia

In Brief The spectrum of ciliary disease has widened from a primary upper and lower respiratory tract problem with the appreciation of the key role of sensory cilia. Five disease causing mutations have been discovered, but given the complexity of cilia, many more are likely to be found in the future. Primary ciliary dyskinesia may present with upper or lower airway disease, or be diagnosed after the discovery of associated conditions such as heterotaxy, complex congenital heart disease, and severe esophageal disease. Screening tests include nasal nitric oxide and in vivo measurements of mucociliary transport. Definitive diagnosis is by ciliary biopsy with measurement of ciliary beat frequency and pattern, followed by electron microscopy. Ciliary culture may help distinguish primary ciliary dyskinesia from ciliary abnormalities secondary to infection. Increasingly, genetic testing is becoming available. Once diagnosed, the severity is assessed, and follow-up should be in clinics with expertise in all areas of the condition. The evidence base for current treatment is weak, with no randomized controlled trials; all therapies are directed at complications, not the underlying abnormality. Lower airway disease is treated with airway clearance, antibiotics, and encouragement of exercise. A conservative approach to chronic secretory otitis media is advised. Although in many cases the patient is stabilized by medical therapy, some will go on to lung transplantation. In the future, specific therapies to reverse the ciliary dysfunction may become available. This article reviews recent advances in the genetics of primary ciliary dyskinesia and discuss the expanding spectrum of ciliopathy. We discuss the state of the art diagnostic tests, and review the age-related presentations. Finally, we discuss the management of the condition.

Primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a genetic condition characterised by a variety of ciliary ultrastructural defects that result in cilia that are either stationary or beat in a dyskinetic fashion. Ineffective ciliary movement impairs mucociliary clearance resulting in mucus retention. This predisposes to recurrent chest infections, which may progress to bronchiectasis. PCD can present in infancy or late adulthood due to varying patterns of symptoms. Kartageners syndrome accounts for approximately 40% of patients. Late diagnosis is common despite symptoms of a daily moist cough and nasal discharge from the neonatal period. PCD is associated with a progressive decline in lung function associated with the development of widespread bronchiectasis. Early diagnosis followed by meticulous follow-up, antibiotic therapy and physiotherapy may halt this. With optimal treatment the prognosis is good. Diagnosis of PCD requires the evaluation of ciliary beat frequency, beat pattern and ultrastructural analysis of nasal ciliated epithelium. There are now three National Specialist commissioning Advisory Group (NSCAG)-funded centres established for the diagnosis of PCD.

Ciliary reorientation is evoked by a rise in calcium level over the entire cilium.

Internal Ca2+ levels control the pattern of ciliary and flagellar beating in eukaryotes. In ciliates, ciliary reversal is induced by a rise in intra-ciliary Ca2+, but the mechanism by which Ca2+ induces reversal is not known. We injected the fluorescent Ca2+ indicator Calcium Green into a ciliate Didinium nasutum and observed the intra-ciliary Ca2+ level during the initial reversed stroke preceding spontaneous cyclic reversed beating. In D. nasutum, Ca2+ rose throughout the length of the cilia undergoing initial reversed stroke. Electron microscopy with a combined oxalate-pyroantimonate method showed Ca2+ deposits distributed throughout the reversed cilia. We injected caged Ca2+ into D. nasutum and irradiated the base or mid region of the cilia with UV to locally increase Ca2+ concentration. Uncaging Ca2+ in the middle of the cilia produced reversal distally, but not proximally to the site of Ca2+ release. These results strongly suggest that not only Ca2+ influx sites, but also Ca2+ binding sites and vectoral bending machineries for ciliary reversal, are distributed throughout the cilium.

Ciliary Beat Pattern is Associated with Specific Ultrastructural Defects in Primary Ciliary Dyskinesia

<h2>Abstract</h2><h3>Background</h3> The main symptoms of primary ciliary dyskinesia (PCD) are nasal rhinorrhea or blockage and moist-sounding cough. Diagnosis can be difficult and is based on an abnormal ciliary beat frequency, accompanied by specific abnormalities of the ciliary axoneme. It is unknown whether determining ciliary beat pattern related to specific ultrastructural ciliary defects might help in the diagnosis of PCD. <h3>Objective</h3> We sought to determine ciliary beat pattern and beat frequency (CBF) associated with the 5 common ultrastructural defects responsible for PCD. <h3>Methods</h3> Nasal brushings were performed on 56 children with PCD. Ciliary movement was recorded using digital high-speed video imaging to assess beat frequency and pattern. Electron microscopy was performed. <h3>Results</h3> In patients with an isolated outer dynein arm or with an outer and inner dynein arm defect, 55% and 80% of cilia were immotile, respectively. Cilia that moved were only flickering. Mean CBF (± 95% CI) was 2.3 Hz (± 1.2) and 0.8 Hz(± 0.8), respectively. Cilia with an isolated inner dynein arm or a radial spoke defect had similar beat patterns. Cilia appeared stiff, had a reduced amplitude, and failed to bend along their length. Immotile cilia were present in 10% of cilia with an inner dynein arm defect and in 30% of radial spoke defects. Mean CBF was 9.3 Hz (± 2.6) and 6.0 Hz (± 3.1), respectively. The ciliary transposition defect produced a large circular beat pattern (mean CBF, 10.7 Hz [± 1.1]). No cilia were immotile. <h3>Conclusions</h3> Different ultrastructural defects responsible for PCD result in predictable beat patterns. Recognition of these might help in the diagnostic evaluation of patients suspected of having PCD.

Ciliary beat pattern is associated with specific ultrastructural defects in primary ciliary dyskinesia

Background The main symptoms of primary ciliary dyskinesia (PCD) are nasal rhinorrhea or blockage and moist-sounding cough. Diagnosis can be difficult and is based on an abnormal ciliary beat frequency, accompanied by specific abnormalities of the ciliary axoneme. It is unknown whether determining ciliary beat pattern related to specific ultrastructural ciliary defects might help in the diagnosis of PCD. Objective We sought to determine ciliary beat pattern and beat frequency (CBF) associated with the 5 common ultrastructural defects responsible for PCD. Methods Nasal brushings were performed on 56 children with PCD. Ciliary movement was recorded using digital high-speed video imaging to assess beat frequency and pattern. Electron microscopy was performed. Results In patients with an isolated outer dynein arm or with an outer and inner dynein arm defect, 55% and 80% of cilia were immotile, respectively. Cilia that moved were only flickering. Mean CBF (± 95% CI) was 2.3 Hz (± 1.2) and 0.8 Hz(± 0.8), respectively. Cilia with an isolated inner dynein arm or a radial spoke defect had similar beat patterns. Cilia appeared stiff, had a reduced amplitude, and failed to bend along their length. Immotile cilia were present in 10% of cilia with an inner dynein arm defect and in 30% of radial spoke defects. Mean CBF was 9.3 Hz (± 2.6) and 6.0 Hz (± 3.1), respectively. The ciliary transposition defect produced a large circular beat pattern (mean CBF, 10.7 Hz [± 1.1]). No cilia were immotile. Conclusions Different ultrastructural defects responsible for PCD result in predictable beat patterns. Recognition of these might help in the diagnostic evaluation of patients suspected of having PCD.

Photolysis of caged calcium in cilia induces ciliary reversal in Paramecium caudatum.

Intracellular Ca(2+) concentration controls both the pattern and frequency of ciliary and flagellar beating in eukaryotes. In Paramecium, it is widely accepted that the reversal of the direction of ciliary beating (ciliary reversal) is induced by an increase in intra-ciliary Ca(2+) levels. Despite this, the Ca(2+)-sensitive region of the cilium that initiates ciliary reversal has not been clearly identified. We injected caged calcium into living P. caudatum cells and applied ultraviolet (UV) light to portions of the injected cells to raise artificially the intracellular Ca(2+) level ([Ca(2+)](i)). UV application to the upper ciliary region above the basal body induced ciliary reversal in injected cells. Furthermore, UV application to the tips of cilia induced weak ciliary reversal. Larger areas of photolysis in the cilium gave rise to greater angles of ciliary reversal. These results strongly suggest that the Ca(2+)-sensitive region for ciliary reversal is distributed all over the cilium, above the basal body.

Analysis of ciliary beat pattern and beat frequency using digital high speed imaging: comparison with the photomultiplier and photodiode methods

BACKGROUNDThe aim of this study was to determine the relationship of the power and recovery stroke of respiratory cilia using digital high speed video imaging. Beat frequency measurements made using...