Related Ciliates Research Articles

Dispersal of the parasitic ciliate Lambornella clarki: implications for ciliates in the biological control of mosquitoes.

Lambornella clarki (Ciliophora: Tetrahymenidae), an endoparasite of Aedes sierrensis (Diptera: Culicidae), is dispersed by infected adult mosquitoes. Invasion of the ovaries induces parasitically castrated females to exhibit oviposition behavior and thereby actively disperse ciliates through deposition into water. Oviposition behavior of infected females is prolonged and mimics that of normal gravid females in their first gonotropic cycle. Adults of both sexes also passively disperse ciliates by dying on water surfaces, and infected adults are more likely to die on water than uninfected adults. Ciliates dispersed by infected adults can infect larvae and form desiccation-resistant cysts. Parasite-induced dispersal by hosts, desiccation-resistant cysts, an active host-seeking infective stage, and high infection and mortality rates all indicate significant biological control potential for these and related ciliates against container-breeding mosquitoes.

Morphogenesis of infraciliature in the entodiniomorphid ciliate Eudiplodinium maggii

The morphogenesis of ciliary zones has been studied in the ciliate Eudiplodinium maggi which has a vestigial somatic infraciliature consisting of subcortical barren kinetosomes. These replicate and migrate into the subequatorial ciliary anlagen of the dividing cells. The kinetid pattern of the barren kinetosomes changes sequentially to that of the ciliary zones. Postciliary and transverse microtubules are derived from basal and cortically directed microtubules while a dense spur coincides with the origin of the kinetodesma. All kinetics produce potential cytopharyngeal components. Nematodesmata originate in granular subkinetosomal dense plates, while two of the three types of cytopharyngeal ribbon are formed from tansverse microtubules. A spatial selectivity ensures that these components extend only from specific kinetids. It is concluded that 91) morphogenesis of the intricate cytoskeletal network of infraciliature involves a “pattern generator” in the vestigial somatic kinetids; and 92) entodiniomorph stomatogenesis in not truly apokinetal but is more like the telokinetal process of related ciliates.

Can Ciliates Adjust Their Intermembranellar Spacing to Prey Size?

The most rapidly cleared particle size has been reported to increase with the body size of the ciliate, a relationship attributed to changes in the morphological features of the oral apparatus. This study examined the possibility that the spacing of the adoral zone of membranelles (AZM) in Blepharisma japonicum could change or adapt to different sizes of prey. To test this hypothesis, specimens of B. japonicum were cultured on the bacterium Proteus vulgaris, the small ciliate Tetrahymena pyriformis, and smaller individuals of B. japonicum, each of which represented a different size of prey. After completing the culture period, a portion of the AZM was viewed by scanning electron microscopy and measurements of intermembranellar spacing were made from the micrographs. Significant differences (P = 0.01) in intermembranellar spacing were found between treatments: the smaller the prey size, the greater the spacing between the cilia of adjacent membranelles. The relationship between body size and particle size in Blepharisma cannot be explained by the inverse relationship already noted. The possibility remains that other oral structures (e.g., the gullet) may govern this relationship. In natural waters, the range of food particle sizes often changes seasonally. Therefore, filter feeding organisms would benefit by being adaptable to different particle sizes. Copepods have been shown to shift their grazing pressure from one size of particle to another in order to take advantage of peak particle concentration (Poulet, 1974). Nival & Nival (1976) formulated an equation for filter feeding efficiency from a number of quantitative setal characteristics including setal spacing. They were able to show that the most efficiently filtered particle size increased throughout the maturation of the copepod. Richman et al. (1977) suggested that the flexibility in copepod feeding behavior cannot be explained solely by the mechanism of a fixed sieve, but they admitted not being able to offer an alternative explanation until the kinetics of filter feeding become more clearly understood. Ciliates, like copepods, are suspension (filter) feeders, but unlike copepods, possess cilia rather than setae for filtering. Fenchel (1980a,b) studied suspension feeding organelles and suspension feeding efficiency of ciliates in relation to particle size. He found: (1) that the free space between membranellar cilia determined the minimum size of particle retained; and (2) that the size of particle most rapidly cleared increased with the size class of Blepharisma americanum (see Fenchel, 1980b). He attributed the latter relationship to changes in the morphological properties of the oral apparatus. The oral apparatus of Blepharisma consists of both oral ciliature and cytopharyngeal struc1 We thank David Montagnes, Guy Gilron, and Stephen Wickham for their enthusiastic support and helpful criticism throughout this investigation. Research supported by the Department of Zoology and by N.S.E.R.C. Canada Operating Grant A-6544 awarded to D. Lynn. 2 Person to whom reprint requests should be addressed. TRANS. AM. MICROSC. SOC., 104(4): 333-340. 1985. ? Copyright, 1985, by the American Microscopical Society, Inc. This content downloaded from 157.55.39.27 on Sat, 26 Nov 2016 04:15:15 UTC All use subject to http://about.jstor.org/terms TRANS. AM. MICROSC. SOC. tures (Giese, 1973). The two major components of the oral ciliature are: (1) the adoral zone of membranelles (AZM), which functions to set up a vortex and draw in food particles from the surrounding water; and (2) the undulating membrane, which directs the particles into the cytostome (Giese, 1973; Sleigh & Barlow, 1982). Since the AZM functions to concentrate the food particles, it also may function in the selection of particle size (Fenchel, 1980a). In the present study, intermembranellar spacing was chosen as a possible site of long-term adaptation. The membranelles of the AZM are anchored by microtubular rootlets interconnected with microfilaments (Dembitzer & Hirshfield, 1966; Giese, 1973). By contraction of the filamentous components, the ciliate may be able to change intermembranellar spacing. However, Fenchel's (1980b) study assumed that intermembranellar spacing is more or less constant for a species. We assumed, then, for the purposes of this study, that the intermembranellar spacing is constant and does not change or adapt to prey size. Blepharisma were fed natural prey organisms to test for the possibility of adaptation of intermembranellar spacing to size of prey after several weeks of exposure to prey. Exposure to actual prey represents a more plausible ecological situation than using latex beads (Fenchel, 1980b) since the prey organisms chosen are known to support growth of Blepharisma (see Giese, 1973). Since a ciliate is more likely to encounter a monospecific patch of prey organisms in the natural environment, Blepharisma has been grown with one prey species at a time. MATERIALS AND METHODS

Coexistence of Congeneric Ciliates (Karyorelictida: Loxodes) in Relation to Food Resources in Two Freshwater Lakes

L. magnus et L. striatus cohabitent dans l'hypolimnion de deux lacs biologiquement productifs (Esthwaite Waters et Priest Pot, Grande Bretagne). Le partage des ressources alimentaires parait etre le principal mecanisme facilitant leur coexistence

PHOTOMOVEMENT RESPONSES OF THE HETEROTRICHOUS CILIATE Blepharisma Japonicum

AbstractLight‐induced movement responses of the heterotrichous ciliate Blepharisma japonicum were studied by physiological experiments. Two photosensory responses could be identified. A step‐up photophobic response is observed as a very rapid backward movement. Microbeam irradiations of individual cells showed that only the anterior part of the ciliate is able to perceive the light stimulus that mediates the phobic reaction. The action spectrum peaks at approximately 400 nm, which indicates that a blue light receptor is involved.Positive photokinesis of Blepharisma could be shown as a forward movement that is accelerated by increasing the applied photon fluence rate. The steady state level of the velocity depends highly on wavelength and photon fluence rate of the actinic light. After specific inhibition of the phobic reaction bv 1 m/W NH4+, photokinesis can be induced by microbeam irradiation at any part of the cell.We isolated two main pigments by thin layer chromatography and characterized them as hypericin‐like compounds: a red pigment that is obviously responsible for the red color of the ciliates (= blepharismin). and a yellow one with maximal absorption near 420 nm. The possible photoreceptor functions of these pigments are discussed.We could not find in Blepharisma a distinct phototactic behavior which is so typical for the related ciliate Stentor.

Continuous culture of the ciliate Tetrahymena pyriformis on Escherichia coli

The ciliated protozoan Tetrahymena pyriformis was grown in a chemostat fed with a culture of Escherichia coli overflowing from another chemostat. Densities of the protozoan and bacterial populations, mean volume of protozoan cells, yields of protozoan volumes and numbers, and filtering rates of protozoans per cell and per unit volume of biomaterial were determined at five different dilution rates. The data obtained supplement other data already available for the popular test organism T. pyriformis, and they are also comparable with data available for related ciliates.

The Loch Eil project: Population characteristics of ciliate protozoans from organically enriched sea-loch sediments

The population characteristics of marine, benthic ciliate protozoans from the sediments of Loch Eil and the Lynn of Lorne on the west coast of Scotland were investigated in relation to the effect of effluent discharge from a pulp and paper mill. During the 12-month field sampling programme, differences in population density, species occurrence, and diversity were found between the ciliate communities from sediments subjected to varying degrees of organic enrichment. These differences did not seem to be related to changes in temperature or any other seasonal factor or to fluctuations in the benthic meiofauna or diatoms. The largest and most diverse ciliate populations were found in the most polluted sediments and typically included microaerophilic species characteristic of sulphureta. Variations in ciliate population density in the samples from the station nearest the effluent outfall were correlated with effluent discharge during the preceding month. The sediments from the Lynn of Lorne were very sparsely populated. The occurrence of benthic ciliates in relation to a gradient of organic enrichment is discussed and a succession of ciliate species along such a gradient is suggested.

Caractéristiques Ultrastructurales du Cortex et des Membranelles du CiliéEspejoia mucicola (Oligohymenophora, Hymenostomata, Tetrahymenina)

It was shown in a detailed study of the cortex and buccal organelles of Espejoia that, at the ultrastructural level, the general plan of organization of this ciliate conforms to that of Tetrahymenina. Specific variations seen in the cortex and membranelles bring out the very pronounced affinities of Espejoia to the genus Glaucoma and other related ciliates. In view of the foregoing and on the basis of reccent findings on morphogenesis, we confirm the taxonomic position of Espejoia mucicola among Tetrahymenina in the family Glaucomidae.

Some observations on the division of five species of commensalic ciliates in relation to water propulsion

A study was made to understand whether there is any correlation between the physiological or morphogenetic activities of commensalic ciliates and the cycles of water propulsion of their hosts. Commonly occurring species ciliates. Boveria teredinidi, Trichodina balakrishnia, Nucleocorbula adherens, Thigmozoon fencheli and Nyctotherus marina from the hosts Teredo furcifera and Nausitora hedleyi were used. The total number and the individuals in division for each species of ciliates were noticed. The results obtained indicate that there is no correlation between the activities of these ciliates and cycles of water propulsion. The data were statistically analysed. It was found that shipworms below 8 mm. in size were not infected with these ciliates. This shows that infection takes place, not from the parent's body but from the outside water after a definite period of growth of the host. An increase in number of commensals in relation with the increase in size of the host was observed. There is a decline in numbers in the oldest hosts. The number of dividing individuals also follows the same pattern of occurrence.

A Redescription of Climacostomum virens (Ehrenberg) Stein and Proposal of a New Heterotrich Ciliate Family, Climacostomidae fam. n.

SYNOPSIS. Structure of the vegetative and asexually dividing forms of the large ciliate Climacostomum virens is redescribed with emphasis on stomatogenesis. These findings are discussed in relation to the taxonomic and possible evolutionary position of Climacostomum among heterotrichous ciliates. Comparative considerations of the buccal and somatic structures as well as of the stomatogenic patterns in this and other closely related ciliate genera indicate the need for placing Climacostomum and Fabrea in a new family, CLIMACOSTOMIDAE. The morphologic evidence suggests that Climacostomum may represent a line linking Fabrea and Stentor.

Excystation of apostome ciliates in relation to molting of their crustacean hosts. II. Effect of glycogen.

To test the hypothesis that a substance or substances normally present in the blood and tissues of pre-molt crabs initiates metamorphosis and subsequent excystation of apostome phoronts, we put excised hermit crab gills bearing Hyalophysa and Gymnodinioides phoronts in sea-water-antibiotic solutions containing blood from other species of crabs or low concentrations of glycogen. As a control gills from the same crab were put into the sea-water-antibiotic mixture alone. The glycogen solutions were more effective in inducing both metamorphosis and excystation of the phoronts than the heterologous crab blood. In repeated trials, in which the controls showed no changes, metamorphosis and excystation occurred with glycogen concentrations of 0.12 to 0.5%. This was true even if the phoronts were on gills taken from a hermit crab only recently molted and hence far from its next molt.

A New Species of Trichodina (Ciliata) from the Urinary Tract of the Muskalonge, with a Repartition of the Genus

In 1932 the author described Trichodila renicola from the urinary tract of the pickerel, Esox iiger, in Oneida Lake. This was the first record of a Trichodina from the urinary bladder of a fish. On numerous subsequent occasions the urinary tract of Esox lucius from various localities was examined for related ciliates, but with negative results. An added interest therefore attaches to the discovery of a similar parasite in the urinary passages of the muskalonge, Esox masquinongy, of Chautauqua Lake, N. Y. This parasite was present in all adult muskalonge examined.