Michael A. Sleigh's research while affiliated with Freshwater Biological Association and other places

Publications (84)

Article
In the microbe-driven ecosystems of the open ocean, the small heterotrophic flagellates (sHF) are the chief microbial predators and recyclers of essential nutrients to phototrophic microbes. Even with intensive molecular phylogenetic studies of the sHF, the origins of their feeding success remain obscure because of limited understanding of their mo...
Article
Experiments on the capture and ingestion of microspheres and algal cells of different sizes presented at different concentrations, alone or in combination, showed that feeding activity and ingestion rates were dependent on the concentration and size of food particles; larger particles were preferred to smaller ones and algal cells to microspheres o...
Article
Bodo saltans was isolated from a chalk stream and fed with pure cultures of seven bacteria obtained from the same river. The flagellates were allowed to migrate into suspensions of either of two bacterial species in a T-maze at 20–22°C. There was a significant difference (P < 0.01) between the numbers of flagellates which migrated into suspensions...
Article
The distribution and abundance of protozoa in two chalk streams were studied. Particular attention was given to the ciliates and amoebae associated with the dominant submerged macrophyte, Ranunculus penicillatus. Highest numbers of protozoa occurred in habitats in the stream where the current velocity was reduced. Mean standing crops of ciliates, f...
Article
1Surfaces in flowing water are covered by boundary layers within which the velocity of flow ranges between zero at the surface and the velocity of the main stream at the limits of the boundary layer.2Many organisms are small enough to live entirely within the boundary layer and so are subjected to much smaller drag forces than if they were exposed...
Chapter
Protozoa, most of which have long been considered as unicellular animals, have been studied for over 300 years, at first as microscopic curiosities, later as organisms causing disease, and more recently as important components of ecosystems. Protozoology, the study of protozoa, is a discipline with a substantial following throughout the world.
Article
Protozoa are the main consumers of heterotrophic bacteria in aquatic habitats. The numbers of these bacteria and protozoa in oligotrophic areas of the open ocean are low, and current methods lack the sensitivity to assess rates of bacterivory in such waters. A new method is proposed for estimating bacterivory on dual radioactively labelled natural...
Article
Bacterivorous protozoa secrete glucosaminidase enzymes which digest peptidoglycans in bacterial cell walls. Phagotrophic protozoa store digestive enzymes in lysosomes before release into food vacuoles where digestion takes place initially at acidic pH. The quantity of glucosaminidase can be assayed by measuring the rate of formation of the fluoresc...
Article
The rates of ingestion of bacteria and of accumulation of bacterial biomass by hungry Pteridomonas danica and Paraphysomonas imperforata were measured using dual radioactive-labelled bacteria in experiments lasting 4–8 h. Pteridomonas continuously consumed 4–5 bacteria h−1 throughout experiments lasting 8 h, irrespective of bacterial concentration...
Article
A flow cytometric sorting technique for direct determination of bacterial biomass assimilation by phagotrophic flagellates was developed and tested in laboratory culture experiments. Living Vibrio bacteria were quantitatively pulse-chase labelled with [(35)S]methionine tracer and fed to Pteridomonas flagellates. Flow sorting revealed that the isoto...
Article
A flow cytometric sorting technique for direct determination of bacterial biomass assimilation by phagotrophic flagellates was developed and tested in laboratory culture experiments. Living Vibrio bacteria were quantitatively pulse-chase labelled with [35S]methionine tracer and fed to Pteridomonas flagellates. Flow sorting revealed that the isotopi...
Article
Seven of the nine lectins tested bound to food vacuolar membranes and/or the cytostome of the filter-feeding ciliate Euplotes mutabilis. Strongest binding to the cytostome was found with concanavalin A, which labelled the cytostomes of more than 90% of cells within 10 s, and quickly labelled progressively more of the food vacuolar membrane material...
Article
The standing stocks of nanophytoplankton and picoplankton in the northeast Atlantic Ocean in June and July 1996 were quantified using flow cytometry and microscopy. Diatoms and dinoflagellates were analysed by microscopy and coccolithophores, other nanophytoplankton, picoeukaryotic phytoplankton, cyanobacteria (Synechococcus spp.), prochlorophytes...
Article
Heterotrophic bacteria were enumerated by flow cytometry in samples from 200 m depth profiles along the 20°W meridian between 59°N and 37°N during June and July 1996. Bacterial volume estimates made by size fractionation were used in the determination of heterotrophic bacterial biomass. Concentrations of heterotrophic bacteria in the surface mixed...
Chapter
Three groups of Protozoa, the ciliates, dinoflagellates and sporozoans have been grouped together as ‘alveolates’ because typical cells in all three groups have a pair of subsurface membranes, forming inflated or flattened alveoli (fluid-filled cushions), beneath the surface membrane. The close relationship between the groups has been confirmed by...
Article
Small inocula of one of the flagellates Paraphysomonas imperforata, Pteridomonas danica, and Cafeteria roenbergensis were added to suspensions of the bacterium Vibrio natriegens at each of three concentrations between 107 and 108 cells ml-1 and incubated at each of the temperatures 10 degrees C and 25 degrees C. Samples were taken at intervals for...
Article
The standing stocks of nanophytoplankton and picoplankton in the northeast Atlantic Ocean in June and July 1996 were quantified using flow cytometry and microscopy. Diatoms and dinoflagellates were analysed by microscopy and coccolithophores, other nanophytoplankton, picoeukaryotic phytoplankton, cyanobacteria (Synechococcus spp.), prochlorophytes...
Article
Full-text available
The role of microzooplankton herbivory in the fate of phytoplankton production was quantified within 2 biologically contrasting water masses in the NE Atlantic during the summertime. Seawater dilution experiments were conducted to quantify phytoplankton growth and losses due to grazing during 2 Lagrangian surveys, at 60 degrees N and 37 degrees N,...
Article
Heterotrophic flagellates in samples collected over a period of 15 months were classified and enumerated by epifluorescence microscopy of DAPI-stained cells deposited on 1μm polycarbonate filters. Identifications were confirmed using other microscopic techniques. The heterotrophic flagellate community was dominated by bacterivorous nanoflagellates,...
Article
Samples were collected from the top 200 m of the water column at 50 stations during two cruises in different, near equinoctial seasons on an Atlantic transect near the 20°W meridian between 50°N and 50°S. These samples were analysed to determine characteristics of the heterotrophic bacterial populations. Flow cytometry was used to enumerate these b...
Article
Samples collected from 10 depths at 25 stations in September–October 1996 and 12 depths at 28 stations in April–May 1997 on an Atlantic Meridional Transect between the British Isles and the Falkland Islands were analysed by flow cytometry to determine the numbers and biomass of four categories of picoplankton: Prochlorococcus spp, Synechococcus spp...
Article
Full-text available
The composition of picoplankton in near-surface samples collected underway at least every 6 h from a ship sailing from the Falkland Islands to the British Isles was determined by flow cytometry, using both autofluorescence markers and staining with the DNA dye SYBR Green I. Prochlorococcus (0.1 to 0.3 x 10(6) cells ml-l) dominated the phytoplankton...
Article
Bacteria were deposited in tubes as compact pellets by centrifuging suspensions of cultured Vibrio at stationary phase. Numbers and protein biomass of flagellates added to these tubes and of the Vibrio, were followed and compared with the growth of the same and other protists on identical, uncentrifuged Vibrio. The flagellates Bodo saliens and Caec...
Article
Early stages of development of marine bacterial biofilms were represented by cultured or freshly‐collected natural bacteria radiolabelled and deposited on 0.2 μm pore size polycarbonate (Nuclepore) or aluminium oxide (Anopore) filters. A proportion of the bacteria gradually resuspended themselves, but few were lost from the mineral filters; larger...
Article
Zooplankton communities, studied in the surface mixed layer on a 1600m transect across the Arabian Sea, were found to differ in their temporal and spatial response to seasonal forcing. The transect studied, spanned seasonally eutrophic upwelling, mesotrophic downwelling and aseasonal oligotrophic waters. The nano- and microzooplankton communities c...
Article
Artificial bacterial biofilms were formed by making microwave-irradiated, dual-radioisotope-labelled Vibrio bacteria adhere to 0.4 μm pore size filters with albumin. The rate of release of 3H from thymidine label in these bacteria into the surrounding seawater when protozoa were incubated with the biofilm indicated the predator's grazing rate, and...
Article
Phytoplankton, bacteria and microzooplankton were investigated on a transect in the Bellingshausen Sea during the ice melt period in November–December 1992. The transect along the 85°W meridian comprised seven stations that progressed from solid pack-ice (70°S), through melting ice into open water (67°S). The abundance, biomass and taxonomic compos...
Article
Bacterivory by protozoa has been measured by several techniques in laboratory cultures and in natural marine samples from eutrophic, mesotrophic and oligotrophic waters. Different techniques are recommended for use in different situations. Direct counting and biomass (protein) measurement techniques work well on laboratory cultures; thus 120 Vibrio...
Article
Grazing behavior of both individual cells and populations of the marine hypotrich Euplotes mutabilis, a largely benthic ciliate that feeds on suspended particles, was studied using fluorescent latex microspheres. Microspheres of sizes 0.57-, 1.90-, 3.06-, 5.66-, and 10.0-μm diam were offered at concentrations from 102 to 106 ml−1. Their uptake in a...
Article
Plankton samples were collected from 10 depths at 25 stations spaced at intervals of about 4° of latitude along a transect from the British Isles to the Falkland Islands. Four categories of picoplankton were discriminated: Synechococcus spp., Prochlorococcus spp., eukaryotic picophytoplankton and heterotrophic bacteria. The populations in each cate...
Article
Full-text available
Nanoflagellates are ecologically important, but morphological identification requires techniques which are not practicable for use in quantitative studies of populations; alternative methods of accurate recognition of nanoflagellate species in mixed populations are therefore desirable. Fluorescent oligonucleotide probes which hybridize with unique...
Article
Full-text available
Identification problems restrict quantitative ecological research on specific nanoflagellates. Identification by specific oligonucleotide probes permits use of flow cytometry for enumeration and measurement of size of nanoflagellates in statistically meaningful samples. Flow cytometry also permits measurement of intensity of probe binding by cells....
Article
Full-text available
A dual radioactive-labelled bacteria technique using Vibrio (DRLV), developed for laboratory studies on bacterivory, has been refined for use at the concentrations of prey and predators typicially found at sea. Experiments with estuarine water collected in spring and in autumn showed that bacterivorous nanoflagellates (HNF) (concentration 1.38 +/-...
Article
Full-text available
Heterotrophic dinoflagellates and their herbivory were quantified at a coastal site in East Antarctica in the vicinity of the Australian Antarctic station of Davis (68 degrees 35' S, 77 degrees 58' E). The study period, 14 January to 11 February 1994, coincided with the growth and decline of a diatom-dominated phytoplankton bloom. Nine taxa of hete...
Article
The feeding of the marine ciliate Euplotes mutabilis was studied using bacteria (Vibrio natriegens) doubly labelled with 3H-thymidine and 14C-leucine. In the presence of abundant bacteria (30 × 106 bacteria ml−1), an average Euplotes cell (initially without food vacuoles) with a protein content of 12 ng consumed 16 × 103 bacteria in the first hour...
Article
Full-text available
The abundance and biomass of planktonic ciliates in the northwestern Indian Ocean ranged from 31 l-1 and 0.1 μg C l-1 in oligotrophic open- ocean waters to 823 l-1 and 1.2 μg C l-1 in more productive waters of the equator, northern Arabian Sea and Gulf of Oman.
Article
Full-text available
Microzooplankton from water samples collected from depths of between 10 and 50 m at four stations between 47° and 60°N along the 20°W line of longitude during each of three cruises were classified into taxonomic groups and measured to estimate their abundance and biomass. Metazoan members of the microzooplankton were rarely found and their overall...
Article
Full-text available
The coastal sea ice in the vicinity of Davis Station, Antarctica (68 degrees 35' S, 77 degrees 58' E), supported a diverse microbial community which varied in composition and biomass in response to increasing insolation and temperature during the austral summer. To understand more fully the fate of photosynthetically fixed carbon in sea ice, we exa...
Article
Microzooplankton and their herbivorous activity were quantified on a transect in the Bellingshausen Sea along the 85°W meridian between 70°15'S and 67°30'S. The transect was worked during the Austral spring period of November-December 1992, with stations in pack-ice (Gertie/Herbie), ice-edge (Isolde), and open-waters (Jules and Katie) of the margin...
Article
A procedure has been developed for preparing living bacteria, quantitatively labeled with (3)H-thymidine and (14)C-leucine, for short-term grazing experiments. The negligible rate of accumulation in protozoan macromolecules of moieties of bacterial macromolecules labeled with (3)H compared with moieties labeled with (14)C permits estimation of the...
Article
Sediment samples were collected at low tide from eight sandy and muddy shores around Southampton Water on one occasion in July and one occasion in September. The population densities of bacteria and microflagellates were determined and the ciliates in sub-samples were identified to genus level and enumerated. The concentrations of cadmium, copper,...
Article
Heterotrophic free-living flagellates appear to provide the ancestry for all other eukaryote groups. Not only are the oldest surviving anaerobic eukaryotes flagellated protists, but also there appear to be survivors of a lineage of flagellate forms which could have been close to the sources of the main branches of eukaryote evolution. These 'stem'...
Article
The epiphytic algae on surfaces of the macrophyte Ranunculus penicillatus (Dumort.) Bab. var. calcareus (R. W. Butcher) C. D. K. Cook and on Cladophora glomerata (L.) Ktz growing in the River Itchen at Otterbourne near Southampton were studied between February 1984 and June 1985. The river at this site has a mean flow rate of 0.33 m s–1, and is abo...
Article
The in situ growth rates of marine planktonic ciliates from Plymouth Sound were determined after fractionating the natural community into several size categories to remove predators of different sizes. Total community in situ growth rates varied from 0·01 to 0·57 d−1 according to fractionation treatment, with the four most abundant taxa, comprising...
Article
The effects of the toxic metals cadmium, lead, copper, mercury and nickel on the feeding rate of well fed Euplotes mutabilis have been studied. Fluorescent latex beads in various sizes and concentrations have been tested as substitute food particles for the ciliates. After exposing standard cultures of the ciliates to a soluble compound of one of t...
Article
The effects of five treatments with four commonly used fixatives on the abundance and cell volume of marine planktonic ciliates were investigated on a natural community from Plymouth Sound. The fixative treatments were 5% and 9% Bouin's solution, 0.4% acid Lugol's iodine, 1% buffered formaldehyde and 1% glutaraldehyde. The abundance of the aloricat...
Article
Microscopic epilithic algae in the River Itchen at Otterbourne near Southampton and in the Ober Water in the New Forest were studied during 1984 and 1985. The River Itchen rises from chalk springs and has a steady pH near 8.2 and a mean alkalinity of 236 mg HCO3 1−1; at the study site the river is about 16 m wide and 20 cm deep, with a mean flow ra...
Article
Microzooplankton and their herbivorous activity were studied at four stations between 60 and 47°N along the 20°W meridian in mid-summer, as part of the 1989 U.K. Biogeochemical Ocean Flux Study. Microzooplankton were abundant in the surface mixed layer at all stations, with concentrations ranging between 2000 and 14,000 organisms l−1. The community...
Article
Oxyrrhis marina (Dujardin) is a predatory marine dinoflagellate that feeds phagocytically on live phytoplanktonic “prey” cells from the surrounding environment. A rapid method was developed to separate the cell cycle characteristics of these predators from their prey cells in order to study the cell cycle dynamics of this organism. Nuclei from Oxyr...
Article
The two stations, an outer one at Calshot and an inner one at NW Netley, were subject to differing marine and terrestrial influences. A total of 55 ciliate taxa were recorded; 34 taxa were identified to genus and 16 to species. The heterotrophic ciliate community at both stations was dominated by aloricate taxa which comprised >90% of the community...
Article
Cleaned stones or glass slides placed in streams were quickly colonized by vorticellids and Carchesium, whose numbers increased for about 2 weeks before falling to a steady level by about 4 weeks. Platycola populations developed more slowly, but tended to become dominant after 3 or 4 weeks. The populations of peritrichs on surfaces already coated w...
Article
Summary Patterns of water flow around steadily beating comb plates of Pleurobrachia pileus were tracked using suspended plastic beads. The positions of the beads and the comb plates in the plane of the central longitudinal axis of the comb row were digitised from high-speed ciné films covering several beat cycles. All of the data from each sequence...
Article
Summary Parameters of ciliary beating and water propulsion can be studied in a unique fashion in ctenophores because the beat frequency can be controlled. P l e u r o b r a c h i a p i l e u s c o m b plates were driven at frequencies between 2 and 25Hz and at temperatures between 10 and 2 5 ˚C. As frequency is increased from 5 to 25Hz, the rest pe...
Article
The population densities of the main groups of protozoa in the principal protozoan habitats in a chalk stream were surveyed over period of a year or more. These data were used to estimate the mean biomass and annual production of flagellates, ciliates and amoebae in the different habitats, and to make comparisons with the estimated production of ma...
Article
The abundance and biomass of marine planktonic ciliates were determined at monthly intervals at two stations in Southampton Water between June 1986 and June 1987. The two stations, an outer one at Calshot and an inner one at N. W. Netley, were subject to differing marine and terrestrial influences. The potential ciliate production at cach station o...
Article
Full-text available
The terminology used to describe the cytoskeleton of protists is sometimes redundant and confusing. The independent origins of protistology from studies on algae, fungi, and protozoans led to these problems. Additionally, recent studies indicate that seemingly unrelated taxa form new, monophyletic groups. However, homologous structures that support...
Article
Flagellar propulsion takes place in the viscosity-dominated realm of low Reynolds number fluid dynamics. Volumes of fluid are carried in a capture zone around the moving regions of the flagellum, and the flagellar motion achieves propulsion because some of that water is shed from the capture zone, either from the flagellar tip in typical flagellar...
Chapter
The easy distinction between higher animals and higher plants led earlier biologists to extend the animal and plant kingdoms down to the unicellular level and separate algae taxonomically from protozoa. There-after one group was studied by botanists and the other by zoologists, and the separation was perpetuated in spite of the difficulty of defini...
Article
The cilia that propel mucus are specialised for the function in their arrangement, length, some details of structure, beat pattern, beat cycle characteristics, metachronal coordination, local control of beat rate by response to mechanical stimulation and generalised control of beat rate by neurohormones. These features are matched to the properties...
Article
1. The characteristics of ciliary systems are determined by the dominance of viscous effects over inertial effects. 2. The velocity of water propulsion depends on ciliary length, beat frequency, pattern of beating, the arrangement of the cilia and their co-ordination. Beating cilia influence a layer of water only two or three cilium lengths deep, w...
Article
Full-text available
The presence of cilia on epithelia of the respiratory tract was reported more than 150 yr ago, and the two-layer model of mucus transport was put forward more than 50 yr ago. However, it is only in the last 10 yr or so that the motion of mucus-propelling cilia of the mammalian respiratory system has been adequately described, and fluid dynamic stud...
Article
A method of mapping the patterns of origin of flagellar roots around basal bodies in two-dimensional diagrams is suggested, making allowance for the varied orientations of members of a pair or quartet of basal bodies in a cell. The method is used to compare flagellar root patterns in a wide range of protistan groups, and appears to demonstrate simi...
Article
Earlier hypotheses of the origin of flagella appear untenable in the light of recent evidence on the ancestry of eukaryotes. It is suggested that microtubules and flagella evolved early in eukaryote evolution to enhance phagotrophy.
Chapter
Efficient mucociliary clearance from the respiratory tract depends upon successful interaction between a normal propulsive mechanism (the cilia) and a normal transport medium (the mucus). Proper functioning of the ciliary component requires (1) an extensive (but not necessarily complete) coverage of cilia, (2) a normal orientation of the cilia on t...
Article
Human IgM and a bovine, IgM-enriched serum fraction isolated from normal adult serum at concentrations of 0.25–1 mg/ml protein induced a pronounced increase in the metachronal wavelength of the lateral (L) cilia of the sea mussel Mytilus edulis without altering their beat frequency. This change in activity was indistinguishable from that induced by...
Article
Particular attention was given to the ciliates and ameobae associated with the dominant submerged macrophyte, Ranunculus penicillatus. Highest numbers of protozoa occurred in habitats in the stream where the current velocity was reduced. Mean standing crops of ciliates, flagellates and amoebae were 32.5, 2.9 and 2.0 mg dry wt m-2 of stream bed resp...
Chapter
The function of the respiratory tract is gas exchange; the respiratory mucosa is continually exposed to the inhaled air and its contaminants, in the form of dust particles, bacteria and toxic gases. To function normally under most conditions, the respiratory tract has become specialized, developing the necessary defence mechanisms to prevent the ot...
Article
A quantifiable assay is described in which the lateral cilia of the sea mussel Mytilus edulis are used to examine the effects of serum on ciliary function. Human sera and sera from a variety of animals have been found to induce a change in ciliary metachrony. This alteration in activity appears to be brought about by the agglutination of adjacent c...
Article
The beat pattern of rabbit tracheal cilia has been investigated using high-speed cine photography and scanning electron microscopy, on cultured epithelia of known orientation. The cilia normally rest in the position reached at the end of the effective stroke, the ciliary tips pointing towards the oropharynx. Each beat begins with a recovery (or pre...
Article
The roles of flagella and their functioning in unicellular organisms of various groups are described. Water propelled around a cell by the flagellum may cause locomotion of the cell and may bring near to the cell food particles that can be filtered from the water and phagocytosed. For purpose of locomotion alone, a relatively simple flagellar activ...
Article
Laboratory growth rates of six species of Gymnamoebia, isolated from English chalk streams and cultured on bacteria, have been determined at four different temperatures. Generation times ranged from 4.46 to 33.3 h. A linear relationship between log10 specific growth rate and the reciprocal of the absolute temperature was demonstrated for four speci...
Article
The palate epithelium of the frog was examined by scanning electron microscopy, light microscopy and high speed cine micrography. The cilia remain stationary for much of time in the end-of-effective stroke position. Each beat cycle begins with a forwardly-directed recovery stroke lasting about 60 ms, followed by an effective stroke towards the oeso...
Article
The fluid movement around a beating cilium is related to the proximity of the cell surface and the presence of other cilia as well as to the length and speed of movement of the cilium and the fluid viscosity. The envelope model for propulsion of ciliated micro organisms predicts velocities of propulsion relatively accurately for cilia beating in sy...
Article
The form of beat of cilia and the structure of the metachronal wave on the lateral gill epithelium of Mytulus edulis have been studied on living material by interference-contrast microscopy and stroboscopic illumination, and compared with the same features in rapid-fixed preparations studied by light microscopy and with the scanning electron micros...
Article
Data derived from the analysis of cinemicrographs of gill cilia of Sabellaria and abfrontal cilia of ctenidial filaments of Modiolus have been used in calculations of elastic constants and bending moments of the cilia and their components. Values for the elasticity of the cilia of 2 to 7 × 10−13 dyne cm2 were obtained, representing a modulus of ela...

Citations

... Microzooplankton (MZP) include organisms with dimensions between 20 and 200 µm in size and, in the Antarctic sea, they comprise mainly ciliates (aloricate and tintinnids), heterotrophic dinoflagellates, the first larval stage of micrometazoans and other protozoa (Foraminifera, Radiozoa, Cercozoa and Heliozoa (Monti and Fonda Umani 2000;Gowing and Garrison 2003;Monti et al. 2016). Microzooplankton can play a key role in removing small phytoplankton biomass (Burkill et al. 1995;Sherr and Sherr 2007;Garcia et al. 2016) and, at the same time, heterotrophic protists can be considered as a food sources for a large number of pelagic organisms such as krill and salps (Calbet and Saiz 2005). The recent shift to small phytoplankton cells affects the structure and dynamic of the Antarctic food structure (Beans et al. 2008;Mendes et al. 2013), with MZP becoming more and more important in the Southern Ocean ecosystem as a predator of smaller phytoplankton. ...
... The teiotroch helps in its dispersal. Vorticella companula is generally a gregarious solitary species and typically form pseudocolonies because of telotrochs settling on the same substrate and very close to the mature organisms 53 . Euplotes minuta is the second most dominant species found to be dominant in Ayiramthengu mangrove ecosystem. ...
... Two key AMT aims have been quantifying causes of variability in planktonic ecosystems and delivering ground-truth data for satellite missions. The phytoplankton community taxonomic composition has been studied in the AMT programme using Flow Cytometry (FC) (Tarran et al., 2001(Tarran et al., , 2006, FC and FlowCAM for the microplankton community groups Fileman et al. (2017), or by filter examination by Scanning Electronic Microscopy focusing only on Coccolithophores (Poulton et al., 2017). However, there is a lack of studies quantifying the cell numbers of the whole phytoplankton community, in particular, species with cell diameter >10 µm. ...
... In the absence of direct measurements, we estimated doubling times of oceanic sHF using the results of feeding experiments with the sHF proxy model, the large-size P. danica isolate (P. danica L, Zubkov and Sleigh, 2005) as explained below. ...
... and Platycola spp. were the dominant peritrich ciliates (Harmsworth et al. 1992). McCollin (1993) sampled 15 sites and recorded 30 species of diatoms (Bacillariophycae) living on stones and plants. ...
... The formation and propagation of these waves is due to hydrodynamic forces between the moving cilia (Machemer, 1974). The metachronism of cilia that transport mucus is irregular and the degree of coupling between cilia and the metachronism could vary with the frequency of beating (Sleigh, 1984). The ciliary beat frequency ranges from 6 to 16 Hz (Lopez-Vidriero & Clarke, 1982). ...
... Despite such an essential role in aquatic ecosystems, their taxonomic diversity is high and not well known. In the early nineties, Sleigh (Sleigh, 1991) discussed the taxonomy of heterotrophic protists, which are the main components of the nano-microzooplankton community, and stated "many species, and possibly phyla, remain to be described" (Sleigh, 1991). Today, almost 20 years later, and despite progress in molecular biology techniques, protozoan taxonomy is still subject to study, discussion and controversy (e.g. ...
... This micro-sized protist is covered with thousands of cilia, which are finger-like membranous organelles that beat rhythmically, affording the organism a means for locomotion, obstacle avoidance and food gathering. Cilia are also found within other microscopic [3] and complex organisms, including the bronchial epithelia of mammals, where they drive the mucociliary escalator [4]. Their collective movement can generate several patterns in order to achieve tasks additional to locomotion, such as parallel manipulation; metachronal (sequential) waves are an emergent phenomenon instantiated in cilia arrays towards achieving these tasks. ...
... The diversity of ciliated protozoa on a global scale is fairly uniform. Nevertheless, numerous studies show that in some territories, and in water bodies of different types, the diversity of ciliated protozoa differ significantly [4][5][6][7][8][9][10][11][12]. Compared to the potential diversity, the realized diversity is dynamic and reflects the specific conditions of each water body, leading to the dissimilarity of the fauna. ...
... However, similar to that observed in oceanic bacteria 22 , the pulsed 33 P i continued to be assimilated into cell macromolecules at an unchanged rate, which started slowing down only after 5 h (Fig. 3a, c). Usually in pulse-chase experiments, incorporation of a pulsed molecule (e.g., amino acid or nucleoside) into bacterial macromolecules halts abruptly upon dilution with the chase, because the intermediate cellular labile pool of the pulsed molecule is small, e.g., 5% of the tracer incorporated into macromolecules 33 . In the case of P i , that labile pool was 10×-20× larger than the amount assimilated into cellular macromolecules (Fig. 3b, d at the 3 h time point). ...