John Blake (1947–2016) was a leader in fluid mechanics, his two principal areas of expertise being biological fluid mechanics on microscopic scales and bubble dynamics. He produced leading research and mentored others in both Australia, his home country, and the UK, his adopted home. This article reviews John Blake’s contributions in biological fluid mechanics, as well as gives the author’s personal viewpoint as one of the many graduate students and researchers who benefitted from his supervision, guidance and inspiration. The key topics from biological mechanics discussed are: “squirmer” models of protozoa, the method of images in Stokes flow and the “blakelet” solution, discrete cilia modelling via slender body theory, physiological flows in respiration and reproduction, blinking stokeslets in microorganism feeding, human sperm motility and embryonic nodal cilia.

The stereocilia of the inner ear are unique cellular structures which correlate anatomically with distinct cochlear functions, including mechanoelectrical transduction, cochlear amplification, adaptation, frequency selectivity and tuning. Their function is impaired by inner ear stressors, by various types of hereditary deafness, syndromic hearing loss and inner ear disease (e.g. Ménière's disease). The anatomical and physiological characteristics of stereocilia are discussed in relation to inner ear malfunctions.

We examined whether infection by the monogenean Heterobothrium okamotoi induces production of specific antibodies against oncomiracidia and their cilia, larvae on the gills, and adults on the branchial cavity wall of tiger puffer Takifugu rubripes. We also investigated whether specific antibody production participates in acquired protection against H. okamotoi. Sera from persistently infected fish immobilized H. okamotoi oncomiracidia 89 days after exposure and antibody levels (measured by enzyme-linked immunosorbent assays) in the sera against oncomiracidia and their cilia increased compared with sera from control (naïve) fish. Antibody levels in these sera against the larvae and adult stages did not increase. The number of H. okamotoi on persistently infected fish was significantly lower than for control fish (P<0·05) when persistently infected fish and control fish were exposed to oncomiracidia in the same tank. Thus tiger puffer produced specific antibodies against oncomiracidia and their cilia, and acquired partial protection against H. okamotoi. Intraperitoneal injection of proteins of sonicated oncomiracidia or their cilia with an adjuvant also produced oncomiracidium agglutination antibodies in sera from tiger puffer; the antibody levels in these sera against oncomiracidia and their cilia increased compared with sera from control fish (injection of BSA with an adjuvant) at 14, 44, and 75 days after the booster immunization. However, in a parasite challenge at 54–58 days after the booster immunization, the infection levels of fish immunized with parasites of sonicated oncomiracidia or their cilia were the same as the control fish. Western blot showed that sera from persistently infected fish and fish immunized with sonicated oncomiracidia or their cilia recognized similar antigenic bands, suggesting that tiger puffer tends to react against these antigens compared with other antigens. These results indicated that specific antibodies against these cilia and oncomiracidia induced by i.p. injection do not prevent H. okamotoi infection.

Objective: To investigate the relationship between the extent of sinus disease in chronic sinusitis as detected radiologically by computed tomography (CT) scan and the population of cilia (ciliary area) both before and after functional endoscopic sinus surgery (FESS). In a simple way this is a trial to statistically prove that the CT scan could be a valid indicator and a mirror of the histological status of the sinus mucosa.

Design: Twenty adult patients were enrolled in this study. Radiological extension of the sinus disease was quantitated using the classification proposed by Kennedy in 1992 and the ciliary population was studied using scanning electron microscopy and image analysis softwares.

Results and conclusion: The more advanced the sinusitis, as evidenced by CT scans, the more the expected reduction in the ciliary area (CA) and in the ciliary count. But after FESS the degree of ciliary regeneration does not depend statistically on the radiological condition of the sinuses and the degree of opacity prior to intervention, i.e. a statistically valid inverse relationship exists between the radiological stage of sinusitis and the ciliary population pre-operatively but the same relation does not extend to the ciliary population post-operatively.

The bacterium Pseudomonas aeruginosa (PA) produces two carbohydrate binding lectins, designated PA lectin-I and lectin-II (PA-IL, PA-IIL). Both lectins are used by the bacterium to adhere to the glycocalyx of mammalian cells. In addition, the lectins immobilize ciliary beat. The kinetics of ciliary beat inhibition by each individual lectin have been analysed; however, their joint action on cilia has not been reported. Here we demonstrate that PA-IL and PA-IIL inhibit ciliary beat in a similar time-dependent manner. If applied simultaneously, ciliary beat inhibition after five hours of incubation was weaker than if each lectin was applied separately. Thus it can be hypothesized that the lectins compete for the same binding site(s) of the glycocalyx. Sugar inhibition experiments demonstrate that D-galactose and L-fucose inhibit both lectins, although clear preferences of D-galactose for PA-IL and of L-fucose for PA-IIL exist. These interactions have to be kept in mind when designing sugar-based therapies.

The objective of this study was to prove ciliary destruction in the middle-ear mucous membrane in cases of chronic suppurative otitis media (CSOM) and to compare both types of chronic suppurative otitis media with regard to the degree of ciliary destruction and ciliary count using objective quantitative techniques.

The mucosa of the anterior mesotympanum over the promontory was sampled in 10 patients with mucosal CSOM and in another 10 patients with squamous type CSOM. Specimens were examined by scanning electron microscopy in combination with image analysis software techniques in order to study the cilia under higher magnifications and to calculate the ciliary area. Five patients with otosclerosis, no history suggestive of otitis media and normal ear drum appearance served as controls.

Samples were taken and studied at the Faculty of Medicine of Cairo University.

CSOM was found to be associated with significant ciliary destruction and this was more evident in the squamous type than in the mucosal type.

The ciliary beat frequency measurements taken from a nasal polyp from a cystic fibrosis patient were similar to that of the control nasal polyps. The addition of a ciliotoxic lectin produced by Pseudomonas aeruginosa stopped the beating of the cilia as in the controls. This reaction could be blocked by the pre-incubation of the lectin with its inhibitor fucose. As in the control, the addition of fucose after the cilia had slowed resulted in a return to normal ciliary beating within 24 hours. This shows that the delta F508 CF mutation observed in this patient does not affect ciliary beating and suggests that treatment with fucose in the early stages of a Pseudomonas aeruginosa infection could be advantageous for cystic fibrosis patients.

In the human oviduct epithelium during ciliogenesis, short tubular structures were found in the transitional zone between the basal body and cilium. The tubules, termed transitional tubules from their location, were 34–36 nm in diameter and 0.13±0.06 μm in length; the number around a basal body was variable, but usually 4–6. The cytoplasmic leaflets of the tubule membranes were coated by electron-dense material and appeared to be connected to alar sheets. The transitional tubules existed transiently during ciliogenesis. The exact role of transitional tubules is unknown, but considering their location, they may fix the basal body in the apical cytoplasm during ciliary elongation and/or may be related to formation of alar sheets.

Acute and chronic infections cause morphological changes in the respiratory mucosa. The ultrastructure of human respiratory mucosa was studied by scanning electron microscopy from the maxillary sinuses of 28 patients, with chronic sinusitis, from middle turbinates of 60 patients, with recurrent respiratory infections, and from healthy sphenoidal sinuses of 31 patients. A loss of ciliated cells and an increasing number of nonciliated columnar cells with microvilli were seen in 62 per cent of the maxillary sinus mucosa. Ciliary disorientation was seen in 81 per cent of the chronically infected sinus mucosa and eight per cent in the healthy sphenoidal sinuses. Also metaplasia and extrusion of epithelial cells were prominent in chronic infections. Compound cilia were seen in 52 per cent of the samples from patients with chronic sinusitis and in 31 per cent of the healthy sphenoidal sinuses. Short cilia were often seen in infected mucosa indicating ciliogenesis.

The mucociliary escalator is the first line of defence of the upper and lower respiratory tracts (Greenstone and Cole, 1985; Sleigh et al., 1988). Failure of mucociliary clearance is associated with chronic or recurrent respiratory tract infection. Ten patients with chronic rhinosinusitis underwent nasal brushings for the assessment of ciliary beat frequency. In two no beating cilia were seen; in the remainder the mean value was 9.3 Hz ± 2.3; range 6.1–12.8 Hz (n = 8).

Following three months continuous oral antibiotic therapy repeat nasal brushings demonstrated increased ciliary beat frequencies in all patients, mean value 13.7 Hz ± 1.6; range 11.5–16.3 Hz (n = 10); (p<0.001 paired t-test).

Depression of mucociliary clearance can occur secondarily to chronic infection and is improved by prolonged antibiotics.