Species Of Blepharisma Research Articles

Possible Third Step Preventing Conjugation between Different Species of Blepharisma.

In the genus Blepharisma, reproductive isolation between different species appears to be established at least by two barriers: (1) a mating pheromone, i.e., gamone 1, and (2) a factor involved in pair formation. Using four species, we experimentally investigated other potential barriers to interspecific conjugation in Blepharisma, as well as the first and second barriers. Cell-free fluid from type I cells (CFF1) of B. americanum had no effect on B. undulans, B. japonicum, or B. stoltei. Type II cells of B. americanum responded to CFF1 from B. americanum but not to CFF1 from B. undulans, B. japonicum, or B. stoltei. Gamone 1, therefore, seems to be the first reproductive barrier (with the inclusion of B. americanum species [megakaryotype 3]) as reported previously. In pretreated cells with complementary gamones in B. undulans and B. americanum, inter-species pair formation was rare, but pair formation between B. americanum and B. japonicum and between B. americanum and B. stoltei occurred at relatively high frequency. Most of the inter-species B. americanum-B. stoltei pairs underwent nuclear changes specific to conjugation. No significant difference was observed between the intra- and inter-species pairs over the time course of the nuclear changes, but the percentage of abnormal cells was higher in inter-species pairs than in intra-species pairs, and no progenies were produced by inter-species pairs. These results suggest a third barrier or step, in addition to the first and second ones, in nuclear changes after pair formation that prevents interspecific conjugation in Blepharisma.

Taxonomy and molecular phylogeny of two new Blepharisma species (Ciliophora, Heterotrichea) from northeastern China

The morphology and ciliary pattern of two new heterotrich ciliates, Blepharisma orientale n. sp. and B. sinicum n. sp., collected from Sanjiang Plain Wetland, northeastern China, were investigated using living observation and protargol staining. Blepharisma orientale n. sp. is characterized by the following combination of characteristics: limnetic; body in vivo 280–380 × 120–190 μm, slender to elongate, cortical granules dark pink, ventral margin somewhat sigmoid; buccal field about 55–60% of body length; 30–39 somatic kineties; 70–76 adoral membranelles, each comprising two long rows of basal bodies; paroral membrane consists of dikinetids with the posterior third obliquely arranged, both basal bodies in each dikinetid are ciliated. Blepharisma sinicum n. sp. is recognized by the combination of the following characters: limnetic; body 190–260 × 100–170 μm in size in vivo, irregularly sigmoid and slightly bilaterally flattened, dorsal margin curved; cortical granules pale pink in color; buccal field about 60–75% of body length; 25–29 somatic kineties; 53–82 adoral membranelles; paroral membrane consisting entirely of dikinetids. Phylogenetic analyses based on small subunit rRNA (SSU rRNA) gene sequence data recovered the two new species as sister taxa, both the sister group of B. penardi.

Resting Cysts of the Pigmented Ciliate Blepharisma sinuosum Sawaya, 1940 (Ciliophora: Heterotrichea)

The morphology of Blepharisma sinuosum resting cysts and the dynamics of pigmentation at different stages of encystment are presented for the first time. Cyst morphometrics are similar to other Blepharisma species, with three-wall layers, bacteria surrounding the ectocyst, a conical plug, and wrinkly surface toward the plug in mature stages. The vegetative moniliform macronucleus changes to a horseshoe shape, and at early stages, the cystic cytoplasm is homogeneously pigmented, comprising a contractile vacuole; later, pigments polarize toward the plug, decorate the cortical layer, and become brownish. This work reinforces the potential role of pigment dynamics on cyst biology.

Blepharismins used for chemical defense in two ciliate species of the genus Blepharisma, B. stoltei and B. undulans (Ciliophora: Heterotrichida)

It is known that the freshwater heterotrich ciliate Blepharisma japonicum uses five pigments called blepharismins, stored in its extrusive pigment granules, for both light perception and chemical defense against predators. In this work we focused our attention on the defensive strategies of two additional pigmented species of Blepharisma, B. stoltei and B. undulans. In particular: (1) we observed the predator–prey interactions of B. stoltei or B. undulans against one multicellular and two unicellular predators; (2) we clarified the nature of B. stoltei and B. undulans pigments by means of High Performance Liquid Chromatography (HPLC) and Liquid Chromatography Mass Spectrometry (LC-MS); and (3) we demonstrated and compared the toxicity of the purified pigments on a panel of ciliated protists, and against one metazoan predator. The results indicate that the chemical defense mechanism present in B. stoltei and B. undulans is mediated by the same five blepharismins previously characterized for B. japonicum, although produced in different proportions.

Revisiting fifty years of research on pheromone signaling in ciliates

Among protists, pheromones have been identified in a great variety of algal species for their activity in driving gamete–gamete interactions for fertilization. Analogously in ciliates, pheromones have been identified for their activity in inducing the sexual phenomenon of conjugation. Although this identification was pioneered by Kimball more than fifty years ago, an effective isolation and chemical characterization of ciliate pheromones has remained confined to species of Blepharisma, Dileptus and Euplotes. In Euplotes species, in which the molecular structures have been determined, pheromones form species-specific families of structurally homologous helical, cysteine-rich, highly-stable proteins. Being structurally homologous, they can bind cells in competition with one another, raising interesting functional analogies with the families of growth factors and cytokines that regulate cell differentiation and development in higher organisms. In addition to inducing conjugation by binding cells in heterologous fashion, Euplotes pheromones act also as autocrine growth factors by binding to, and promoting the vegetative reproduction of the same cells from which they originate. This autocrine activity is most likely primary, providing a concrete example of how the original function of a molecule can be obscured during evolution by the acquisition of a new one.

Two possible barriers blocking conjugation between different megakaryotypes of Blepharisma.

We investigated mating pair formation between three Blepharisma species Blepharisma undulans, Blepharisma japonicum, and Blepharisma stoltei to determine whether their respective gamones (mating pheromones) effectively induce mating pairs between different species. Cell-free fluid from type II cells (CFF2) of B. undulans (megakaryotype II) induced pairing of B. japonicum and B. stoltei type I cells (megakaryotype IV), and CFF2 of B. japonicum and B. stoltei induced pairing of B. undulans type I cells. Cell-free fluid from B. undulans type I cells (CFF1) did not induce pairing of B. japonicum and B. stoltei type II cells, and CFF1 of B. japonicum and B. stoltei failed to induce pairing of B. undulans. CFF1 from B. japonicum and B. stoltei mutually induced pairing, as previously reported. These results indicate that gamone 2 is common among megakaryotypes II and IV, and that gamone 1 appears to be at least megakaryotype-specific. When cells belonging to megakaryotypes II and IV are separately pre-treated with effective gamones and mixed, mating pairs between megakaryotypes rarely form. Taken together, these results suggest at least two barriers, a gamone and a factor involved in pair formation, that prevent conjugation between different megakaryotypes of Blepharisma.

Morphology and 18S rDNA gene sequence of Blepharisma sinuosum Sawaya, 1940 (Ciliophora: Heterotrichea) from Brazil

The morphology and morphometric data of seven populations of Blepharisma sinuosum from southeastern Brazil were investigated. The description is based on live observations, protargol impregnation, and scanning electron microscopy. Blepharisma sinuosum measures 75–255μm in length and 25–93μm in width and has a spindle-shaped body, pink color, a single contractile vacuole located at the posterior end, 50 adoral membranelles, a conspicuous paroral, 17–35 somatic kineties, a moniliform macronucleus with 2–7 connected nodules, and 3–20 micronuclei. Morphological comparisons with similar species were performed and suggest that B. americanum is the junior synonym of B. sinuosum. The 18S rDNA gene sequence of B. sinuosum was obtained and compared with that of other Blepharisma species. The length and GC content of the obtained sequence is 1652bp and 47.03%, respectively, and has a very high structural similarity (99.9%) with the B. undulans sequence. The validity of the classification of Blepharisma species in morphonuclear subgenera is also discussed.

New Record of Ciliates, Blepharisma undulans and B. steini (Ciliophora: Heterotrichida: Blepharismidae) from Korea

Two ciliate species of Blepharisma were collected from the riverine wetland and mountain peak soil in Korea, Blepharisma undulans Stein, 1867 and B. steini Kahl, 1932, which are reported for the first time from Korea. The description was based on the observations of live and protargol impregnation specimens. Diagnostics of these species (Blepharisma undulans vs. B. steini) are as follows. Body length/width ratio in vivo about 6/1 vs. 2/1, shaped in spindle vs. pyriform to ellipsoid and colored in pinkish vs. reddish. Macronuclei 2 vs. 1, with 4-9 vs. 4-7 spherical micronuclei. Adoral zone of membranelles extends from anterior end to 1/3 vs. 1/2-2/3 of body length, with 47-56 vs. 33-45 adoral membranelles. The numbers of somatic kineties are 22-27 vs. 18-22.

Observations on the Ecology and Morphology of Blepharisma Elongatum (S tokes, 1884), K ahl, 1926)

The colourless Blepharisma species, B. elongatum, is extremely rare. Only a few specimens were found during weekly samplings over a period of seven years. Ecological data were collected during the first year of the investigation. The ciliate was established in cloned, polybacterial cultures in Pringsheim's salt solution. Light and electron microscopical observations revealed, as the most prominent feature, the almost total absence of cortical granules. The general morphology of the ciliate was, however, that typical of Blepharisma. Hence, although B. elongatum has been considered a species not valid by some investigators, our findings are in good agreement with the observations of other previous investigators. Our conclusion is that B. elongatum is a true valid species.

Observations on the morphology and ecology of Blepharisma lateritium ( Ehrenberg, 1831) Kahl, 1932

Blepharisma species are not easily found in the nature and ecological field studies have not yet been performed ( Giese 1973), In Denmark Blepharisma lateritium was first collected by O. F. Müller in the winter 1777/78 and described Glødspilleren 1783, later, 1786 named Trichoda ignita. The organism has not been re found here until 1975 where the author repeatedly collected it in 4 out of 12 ponds or lakes. In 1978 a study was undertaken to determine its seasonal occurrence in an eutrophic pond, where it previously had been observed several times. The number of organisms, collected as well from surface layers as from sediments, was counted weekly. The seasonal fluctuations of small algae (food organisms), temperature, p H and the contents of dissolved O 2 , CO 2 , NH 4 + and H 2 S were determined. For the morphological study the organisms were either observed in vivo or fixed and stained. The field observations showed, that B. lateritium was present only during the winter and the early springtime, maximally in April. Cultures could be maintained only refrigerated (5 °C) and, although the organisms had the same conditions throughout a season, they seemed to display winter-spring maxima like the field organisms. Although B. lateritium is the Blepharisma species first mentioned in the ciliate literature, the present study seems to be the first to demonstrate its morphology by photomicrographs and to report adequate details on its ecology and of its maintenance in laboratory cultures.

Relationships between Natural Populations of the Ciliated Protozoa Loxodes magnus Stokes and L. striatus Penard

Gause (1934, 1935) in classical experiments with Paramecium caudatum Ehrb. and P. aurelia Ehrb. demonstrated that interspecific competition for a limiting food supply, which can lead to the competitive exclusion of one species, may take place in cultures of ciliated protozoa. More recently, considerable work on interspecific relationships in ciliates, both in culture and in the field, has been carried out by Hairston and co-workers. In culture experiments, examples which may be quoted of interspecific competition leading to exclusion are as follows. (1) Between P. aurelia-2 and P. aurelia-3 (Hairston & Kellermann 1965). Sonneborn's numbered syngens of P. aurelia may be regarded as distinct species (Hairston 1958); the nomenclature is that of Gill & Hairston (1972). (2) Between all possible pairs of P. caudatum, P. bursaria (Ehrb.) Focke, P. aurelia-3 and a species of Blepharisma (Vandermeer 1969). Although interspecific competition between ciliates may be demonstrated in culture it is not clear how important it is under natural conditions. Hairston (1958), on the basis of a series of samples from the Huron River near Ann Arbor, Michigan and from a tributary stream and associated woodland seeps, suggested that competition took place between natural populations of Paramecium aurelia-2 and P. aurelia-3 and that environmental conditions were such that P. aurelia-3 won in the river and P. aurelia-2 in the stream. Hairston (1967), however, considered that competition between P. aurelia species was sometimes important but thought that a population of P. aurelia-2 in a woodland seepage area was not influenced by competition with other P. aurelia species, and Gill & Hairston (1972) concluded, from the results of field experiments which involved both separate and simultaneous introductions of P. aurelia-2 and P. aurelia-5 to a woodland seep, that there was no evidence for the competitive exclusion of one species by the other. In other habitats, Brown (1964) considered that alternation of peaks of growth rate shown by species of Vorticella and Aspidisca costata (Dujardin), in an activated sludge plant, indicated competition between these ciliates and Grabacka (1971) suggested that there were inverse relationships between numbers of Loxodes magnus Stokes and L. striatus Penard and between Spirostomumfilum (Ehrb.) Penard and S. minus Roux, in the benthos of some fishponds in Katowice Province, south-west Poland, which indicated competition for a common food supply (algae in the case of Loxodes and bacteria for Spirostomum species). This last suggestion is based on data which are published as histograms in Figs. 9 and 10 of Grabacka's (1971) paper and which may be to some extent re-appraised. Grabacka collected samples, from marginal and mid-pond sites, which were 150-ml mixtures of sediment and overlying water. In samples from coarse-textured sediments, therefore, populations from several adjacent microha-bitats were probably combined in

Regeneration Rate of Blepharisma with Special Reference to the Effect of Temperature*

SYNOPSIS. The regeneration of three species of Blepharisma—americanum, undulans and japonicum (grown in conslant yellow light in a constant‐temperature room at 25d̀C) from specimens of which the hypostome had been removed, was studied under a variety of conditions. The reliability of the methods was checked by an extensive series of experiments with B. americanum and B. japonicum under normal conditions. The time of regeneration of 50% of the individuals was taken as a convenient means for comparing action of various agents. No diurnal rhythm of rate of regeneration was observed. Regeneration is readily affected by the state of nutrition of the cells, starved ones regenerating more slowly than well‐fed ones. Regeneration is accelerated by maintaining the cells at 30d̀ but retarded at 35d̀. Even brief exposures to 40d̀ may retard regeneration. Regeneration is slowed by maintenance at temperatures below 25d̀, and stopped at 10d̀. Cut Blepharisma placed at 5d̀ lose pigment in a “shock” reaction and many die. The injury is more marked in lettuce medium than in balanced salt solution. Between 13 and 30d̀ the rate of regeneration increases with rise in temperature, the Q10′s for the ranges 13 to 18d̀, 18 to 25d̀ and 25 to 30d̀ being, respectively, 6.92, 3.93 and 1.56. The effect of temperature upon division of Blepharisma was found to be similarly sensitive to temperature, the Q10's for the ranges 13 to 18d̀, 18 to 25d̀ and 25 to 30d̀ being 3.87, 2.92 and 1.59, respectively. High and low temperature limits for division were also found to be similar to those for regeneration. Preliminary evidence indicates some degree of thermal adaptation in Blepharisma to both higher and lower temperatures than those usually tolerated. The studies indicate a general similarity in sensitivity of regeneration and division to environmental influences in the various races of the species studied, with some individual variations.

Taxonomy of genus Blepharisma with special reference to Blepharisma undulans.

SYNOPSIS. Three new species of Blepharisma are presented: B. seshachari sp. nov., B. intermedium sp. nov., and B. tropicum sp. nov. Two sub‐species of Suzuki are elevated to specific rank, B. undulans americanum to B. americanum and B. undulans japonicum Suzuki to B. japonicum Suzuki. Stein's taxa for the species Blepharisma undulans are considered to be diagnostic for that species.Important features of morphology and life‐cycle of the above mentioned species are given. Discussion and position of the species Blepharisma undulans are presented and a proposal for the reorganization of the species is made. The possibility of a new key derived from a hypothesis of the phylogeny on an evolutionary basis of the genus is presented. This hypothesis has been extended to include ciliates like Stentor and Spirostomum and its implications discussed.

Conjugation in Blepharisma undulans americanum.

SYNOPSIS.An account of conjugation in an American species of Blepharisma is given. A comparison is also made with the available knowledge of the two Indian species of this genus. In the conjugating pair, the condensed macronucleus shows Feulgen negative regions. Before the conjugants separate, the macronuclear and micronuclear anlagen become distinguishable.The species is characterized by a number of striking features which become noticeable after syngamy. The synkaryon divides thrice giving rise to 8 bodies. Of these, 3 to 7 become the macronuclear anlagen and the rest, the micronuclei. The resorption of the old macronucleus occurs much later, just before the exconjugant attains the vegetative form. No metagamic fissions occur in this species and each exconjugant becomes a vegetative animal in 5 or 6 days. During this period, the macronuclear anlagen arrange themselves in a series and develop slender connections with one another to produce the moniliform macronucleus of the vegetative animal. The micronuclear anlagen, on the other hand, divide by mitosis to attain the vegetative number. In this species 40% to 45% of the exconjugants are viable and the rest die.

Resonances of Biological Cells at Sonic Frequencies

The rate at which Paramecium caudatum is destroyed in a sound field of fixed intensity increases markedly in the neighborhood of 1.2 kc/sec. Similar optimum destructive frequencies have been found for six other species of paramecium and for a blepharisma species. Although the shapes of these animals are too complex to treat on a theoretical basis, reasonable theories can be developed for spheres having radii equal to the average radius of the animal. One theory, based on the existence of a non-rigid membrane with interfacial tension, T, separating two incompressible liquids, gives T = ca. 3 dynes/cm, agreeing in order of magnitude with values found for other cells by very different methods. An alternate theory postulates a rigid envelope surrounding the cell giving coefficients of rigidity about 104 dynes/cm2; this is within the range of values of fibrin gels. Either type of vibration would be excited readily by cavitation. The formulas for these modes and their derivation will be discussed.