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  • 1
    Electronic Resource
    Electronic Resource
    Intraclonal Dimorphism of Caudal Cirri in Euplotes vannus: Cortical Determination (1967)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 14 (1967), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Intraclonal variation in number of right caudal cirri (RCC) occurs within some species of the hypotrichous genus Euplotes. Euplotes vannus, a marine species, may have either 2 or 3 RCC. A single clone always contains individuals of both types. The frequency of individuals of each type within a clone was found to be 0.5. This fact suggested that during division each parental cell gives rise to one daughter having 3 RCC and one having 2.Formation of RCC during division was studied in E. vannus and in E. plumipes, a fresh-water form which always has 2 RCC. The studies were made on living animals and on fixed animals stained with protargol or by the Chatton-Lwoff method. In both species, the new RCC first appear in the right dorsal kineties and later migrate to the ventral surface. The RCC for the proter develop near the parental equator while those for the opisthe form near the posterior end of the parent cell, both sets developing in close proximity to kinetosomes of the kineties. In both species the 2 dorsal kineties furthest to the right each give rise to 2 RCC, one for the proter and one for the opisthe. In E. vannus, however, the third-from-the-right dorsal kinety also produces one right caudal cirrus for the proter. Therefore, in E. vannus it is the proter which always receives 3 caudal cirri and the opisthe which gets only 2. The role of the cortex in determining these events is discussed.Two cases of abnormal caudal cirrus formation are also described. Other aspects of morphogenesis during division, not previously reported, are also presented and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1967.tb02021.x
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  • 2
    Electronic Resource
    Electronic Resource
    Induction of Anti-Actin Drug Resistance in Tetrahymena (2002)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 49 (2002), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Both cytochalasin D and latrunculin B reversibly inhibited Tetrahymena phagocytosis at concentrations similar to those effective in mammalian systems, even though ciliate actins are known to be highly divergent from mammalian actins. Overnight exposure to relatively low (0.25 μM) concentrations of latrunculin B induced resistance in Tetrahymena to the inhibitory effects of that drug, as well as cross-resistance to cytochalasin D. However, much higher (〉30 μM) concentrations of cytochalasin D were required for induction of cross-resistance to latrunculin B. Anti-actin drug resistance in Tetrahymena may involve a general multidrug resistance mechanism and/or specific feedback regulation of F-actin assembly and stability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.2002.tb00231.x
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  • 3
    Electronic Resource
    Electronic Resource
    Affinity-Purification of Concanavalin A-Binding Ciliary Glycoconjugates of Starved and Feeding Tetrahymena thermophila (1999)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 46 (1999), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Development of mating competency in Tetrahymena thermophila requires starvation for at least 70 min in low ionic strength buffer. Pair formation between conjugating cells is blocked at early stages by the lectin Concanavalin A (Con A). To investigate the role of Con A-binding proteins in this induced cellular change and in pairing, and to confirm and extend an earlier study from our laboratory, a method was developed for preparation of Con A-binding proteins from ciliary membrane-rich fractions of T. thermophila. Con A-binding ciliary proteins were prepared from non-starved and starved cells from two wild type strains and a mating mutant, RH179EI. Comparison of these proteins by SDS-PAGE revealed an overall reduction in number of wild-type bands after starvation. In particular, a major band at 28 kDa was present in non-starved cells and absent in starved cells. However, in the mating mutant, no change in banding profile was seen after starvation: the 28 kDa band was present in both non-starved and starved cells. Thus, Con A-binding ciliary membrane proteins undergo a major change during starvation-induced development of mating competency in wild-type T. thermophila. In contrast, the mutant differed from wild-type in overall composition of its ciliary Con A-binding glycoproteins and in the response of these proteins to starvation, suggesting that it may be deficient in its ability to be initiated by starvation. Our results are consistent with the hypothesis that a change affecting ciliary membrane Con A-binding proteins is essential for the cellular response to mating signals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1999.tb04597.x
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  • 4
    Electronic Resource
    Electronic Resource
    Relative Potencies of Different Cytochalasins for the Inhibition of Phagocytosis in Ciliates (1998)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 45 (1998), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Ciliate actins have been reported to exhibit an unusual degree of sequence divergence, within the phylum Ciliophora, and when compared to actins from other organisms. To determine whether these primary structural differences are correlated with pharmacological differences, we investigated the effects of seven cytochalasins on phagocytosis, which has been shown to be actin-dependent in eukaryotic cells. The relative potencies of cytochalasin inhibition of phagocytosis in Spirostomun ambiguum and Paramecium multimicronucleatum were similar. Dihydrocytochalasin B and cytochalasin A were the most potent of the seven cytochalasins in both ciliates, and strongly inhibited phagocytosis at 20-40 μM. Dihydrocytochalasin B was considerably more potent than either cytochalasins B or D, a result unexpected on the basis of reports utilizing other organisms. However, even at concentrations up to 100 μM, dihydrocytochalasin B did not inhibit the rate of Spirostomum defecation. After long-term treatment of Spirostomum with 50 μM dihydrocytochalasin B, the sensitivity of phagocytosis to the drug was reduced. These results indicate that the relative cytochalasin sensitivities of actin-dependent functions in ciliates differ from those of other organisms, and are consistent with the hypothesis that sequence differences might give rise to substantial differences in the pharmacological properties of ciliate actins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1998.tb05090.x
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  • 5
    Electronic Resource
    Electronic Resource
    Cell Pairing during Mating in Tetrahymena: I. Does Phagocytosis or a Cell Surface Receptor Participate in Con A Block? (1988)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 35 (1988), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The lectin, Concanavalin A (Con A), inhibits cell pairing during mating in Tetrahymena and binds to the surface of pairing cells via receptors concentrated around the conjugation junction. Concanavalin A is also ingested in large amounts into food vacuoles. To dispel the possibility that Con A inhibits pairing via uptake into food vacuoles or through induction of food vacuole formation and to strengthen the idea that pairing is blocked through binding of Con A to cell surface receptors, we have conducted three types of experiments: 1) attempts to inhibit pairing by feeding with nutrients and with tantalum, a non-nutritive reagent; 2) a temporal analysis of the presence of food vacuoles in mating cells fed with tantalum; and 3) analysis of the restoration of pairing following the addition of α-methyl mannoside to cells previously treated with inhibitory concentrations of Con A. The results of these studies support the idea that Con A inhibits pairing by binding to receptors located on the cell surface and not by induction of or uptake into food vacuoles. We also present evidence that cells grown in an enriched proteose peptone medium are able to pair and undergo morphogenesis more readily than cells grown in 2% proteose peptone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1988.tb04122.x
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  • 6
    Electronic Resource
    Electronic Resource
    Poly(A)+ RNA from Tetrahymena: Stimulation of Protein Synthesis in Vitro (1979)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 26 (1979), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS Cell-free synthesis of high molecular weight polypeptides, programmed by RNA from Tetrahymena pyriformis strain W is reported, and methods for preparation of the RNA are described. The RNA was extracted by the SDS-phenol-chloroform-isoamyl alcohol technic. The bulk of extracted RNA was ribosomal and on sucrose gradients peaked at -17S and 25S. After heat denaturation all the 25S RNA was converted to 17S. indicating the presence of hidden breaks, possibly the result of nuclease activity during extraction. Nevertheless, when poly(A)–RNA was collected using oligo-(dT)-cellulose column chromatography, it promoted a 15–fold increase in incorporation of [35S] methionine into TCA-precipitable material. Slab-gel electrophoresis and autoradiography of the product revealed 12 different major polypeptides, varying in weight from 28.000 to 65,000 Daltons. A method for preparation of translatable RNA from Tetrahymena will make possible the comparison of messenger RNAs associated with specific cell structures and with different developmental events.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1979.tb04218.x
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  • 7
    Electronic Resource
    Electronic Resource
    Selection of Nonmotile Tetrahymena with Ficoll Underlayers*,† (1979)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 26 (1979), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The mechanisms regulating the development of cilia in Tetrahymena are poorly understood but might be revealed through the study of ciliogenesis mutants. Failure to regenerate cilia after dibucaine deciliation results in continued absence of motility. Therefore, to isolate ciliogenesis mutants efficiently, methods for separating motile and nonmotile cells are essential. We examined the efficacy of Ficoll underlayers for these separations. Ciliates of T. thermophila strain mpr-/mpr (6 mp sens IV) (6-methyl purine-sensitive; mating type IV) were mixed with Ficoll and added as underlayers to separatory funnels containing growth medium. At 27 C most of the cells remained motile and were found in the top layer; at 37 C, there was a time-dependent increase in the number of nonmotile cells and the number of cells in the Ficoll layer. After 150 min at 37 C, most of the cells became nonmotile and were found in the Ficoll layer. Other studies indicated that at 37 C, the cells remained alive and capable of regenerating cilia when deciliated. Thus, it is clear that the Ficoll underlayer effectively separates the majority of nonmotile cells from the majority of motile cells. Evidently, however, at 37 C wild-type T. thermophila exhibit temperature-sensitive phenotypic variability with regard to motility which should be minimized when selecting for mutations affecting motility and ciliogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1979.tb02771.x
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  • 8
    Electronic Resource
    Electronic Resource
    Cortical ultrastructure and chemoreception in ciliated protists (ciliophora) (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 225-264 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The ciliated protists (ciliates) offer a unique opportunity to explore the relationship between chemoreception and cell structure. Ciliates resemble chemosensory neurons in their responses to stimuli and presence of cilia. Ciliates have highly patterned surfaces that should permit precise localization of chemoreceptors in relation to effector organelles. Furthermore, ciliates are easy to grow and to manipulate genetically; they can also be readily studied biochemically and by electrophysiological techniques. This review contains a comparative description of the ultrastructural features of the ciliate cell surface relevant to chemoreception, examines the structural features of putative chemoreceptive cilia, and provides a summary of the electron microscopic information available so far bearing on chemoreceptive aspects of swimming, feeding, excretion, endocytosis, and sexual responses of ciliates. The electron microscopic identification and localization of specific chemoreceptive macromolecules and organelles at the molecular level have not yet been achieved in ciliates. These await the development of specific probes for chemoreceptor and transduction macromolecules. Nevertheless, the electron microscope has provided a wealth of information about the surface features of clliates where chemoreception is believed to take place. Such morphological information will prove essential to a complete understanding of reception and transduction at the molecular level. In the ciliates, major questions to be answered relate to the apportionment of chemoreceptive functions between the cilia and cell soma, the global distribution of receptors in relation to the anterior-posterior, dorsal-ventral, and left-right axes of the cell, and the relationship of receptors to ultrastructural components of the cell coat, cell membrane, and cytoskeleton. © 1992 Wiley-Liss, Inc.
    Additional Material: 41 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070220304
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  • 9
    Electronic Resource
    Electronic Resource
    Ciliary polypeptides and glycoconjugates of wild-type and mutant Tetrahymena thermophila: Starved versus nonstarved (1992)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 13 (1992), S. 26-33 
    Details
    ISSN: 0192-253X
    Keywords: Tetrahymena thermophila ; cilia ; gly-coprotein ; Con A ; Western blot ; lectin ; mating ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: To investigate the role of cilia in mating interactions of Tetrahymena thermophila, ciliary membrane-rich fractions were isolated from two wild-type strains, a non-discharge mucocyst mutant which possesses mating behavior similar to wild-type, and a mating mutant which is able to costimulate cells of complementary mating type but cannot enter into pair formation. In each case, proteins from the ciliary membrane-rich fractions of starved, mating-competent (“initiated”) cells were compared with those from non-starved, mating-incompetent (“non-initiated”) cells, by gel electro-phoresis and lectin blotting. In stained gels, a 43 kDa polypeptide was reduced or absent in initiated cells but present in non-initiated cells, in all strains. In silver-stained gels, a 25 kDa polypeptide was present in all strains, both initiated and non-initiated. In blots probed with Con A-peroxidase, a 25 kDa glycoprotein was present in ciliary membrane fractions from non-initiated cells and absent in membranes of initiated cells of the two wild-type strains and the mucocyst mutant, but is present in initiated and non-initiated cells of the mating mutant (several hypotheses are presented to explain these findings). In addition, ciliary proteins of the mating mutant included at least two unique Con A-binding polypeptides. Our results support the idea that development of mating competence during starvation involves an extensive remodeling of ciliary membranes, and identify a 25 kDa glyco-conjugate as having a potential role in control of pair formation during mating. © 1992 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020130105
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  • 10
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    Immunocytochemical localization of a putative strychnine-sensitive glycine receptor in Hydra vulgaris (2019)
    Springer
    Details
    Publication Date: 2019-04-11
    Print ISSN: 0302-766X
    Electronic ISSN: 1432-0878
    Topics: Biology , Medicine
    Published by Springer
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