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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 37 (1990), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Exocytosis mutants of Tetrahymena thermophila are deficient in mucus release. Experiments to chromosomally locate two of these mutants are described, using the technique of deletion mapping with nullisomic strains. One exo locus has been assigned to chromosome 5.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 36 (1989), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 356 (1980), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 356 (1980), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 12 (1989), S. 1-11 
    ISSN: 0886-1544
    Keywords: ciliary motility ; cAMP ; Ca2+ ; phosphoproteins ; signal transduction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study seeks to identity phosphoproteins in axonemes from Paramecium letraurelia whose phosphorylation responses to adenosine 3′,5′-cyclic monophosphate (cAMP) and Ca2+ parallel responses induced by these agents in ciliary behavior in this cell. In purified rxonemes, over 15 bands ranging from Mr 〉300 kDa to 19 kDa on SDS-PAGE incorporate 32P from adenosine 5′-γ-[32P]tri-phosphate (γ-32P-ATP) at pCa 7 in the absence of cAMP. A major band whose label turns over rapidly was identified at Mr 43 kDa. In the presence of 5 μM cAMP, more than eight bands, but not the Mr 43 kDa band, were labeled additionally or enhanced their labeling. These phosphoproteins and their kinases are structural components of the axoneme. Overall, some of the same major bands are labeled in the presence of cAMP in Triton X-100-permeabilized paramecia that retain their behavioral responses and in axonemes mechanically isolated from these cells. In particular, two major bands have been identified whose phosphorylation is greatly enhanced by cAMP at low concentrations: (1) a 29 kDa polypeptide whose cAMP-dependent phosphorylation is diminished at pCa 4 compared with pCa 7 and (2) a 65 kDa polypeptide whose phosphorylation is pCa insensitive. These polypeptides meet minimal criteria for signal-sensitive regulators of motility parameters in the Paramecium axoneme.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 249-267 
    ISSN: 0886-1544
    Keywords: Paramecium ; trifluoperazine ; cilia ; calmodulin ; calcium ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Trifluoperazine (TFP), a drug that binds to Ca2+-calmodulin (CaM) complexes, altered swimming behavior not only in living paramecia, but also in reactivated, Triton-extracted “models” of the ciliate. By comparing the responses of living cells and models, we have ascertained that two sites of drug action exist in paramecium cilia. Swimming movements were recorded in darkfield stroboscopic flash photomicrographs; this permitted accurate quantitation of velocities and body-shape parameters. When living paramecia were incubated in a standard buffer containing 10 μM TFP, their speed of forward swimming fell over several minutes and their bodies shortened. Untreated paramecia backed up repeatedly and frequently upon transfer to a solution containing barium ions (the “barium dance”), but cells preincubated in TFP did not “dance.” Instead they swam forward slowly for long periods of time without reversing and occasionally then exhibited abnormally prolonged reversals. W7 effects on swimming mimicked low doses of TFP, and the analog W5 did not visibly alter normal swimming patterns. These results suggest that TFP induces a decrease in the intracellular pCa of living paramecia, perhaps by reducing the efficiency of a calmodulin-activated calcium pump in the cell membrane. Paramecia extracted with Triton X-100 and reactivated to swim forward (7 ≥ pCa ≥ 6) were not affected by addition of up to 40 μM TFP to the reactivation medium. We conclude that the main drug effect in living cells is probably not at the axoneme. However, at low pCa, TFP directly affected the ciliary axoneme to shift its behavior to one characteristic of a higher pCa: TFP inhibited backward swimming in models reactivated at pCa 〈 6; instead they swam forward or rocked in place. The mechanism of ciliary reversal in paramecium may therefore depend on an axonemal Ca+-sensor, possibly bound CaM, which is affected by TFP only at low pCa, as has been postulated for other types of cilia.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 31 (1986), S. 195-202 
    ISSN: 0730-2312
    Keywords: protein secretion ; ciliates ; Tetrahymena ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Tetrahymena thermophila is a ciliated protozoan studied by investigators from a wide range of disciplines as a model system for a variety of specialized eukaryoticcell functions. The proteinaceous secretory products of T thermophila have been isolated and characterized [1] and in this study we identify the major secretory product, a 34,000 Mr polypeptide, and use an antiserum prepared against this secretory protein to (1) demonstrate that this 34,000 Mr polypeptide is truly a secreted protein in Tetrahymena and (2) monitor the synthesis and transport of this protein by indirect immunofluorescence and light microscopy during mucocyst biogenesis.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 36 (1988), S. 429-443 
    ISSN: 0730-2312
    Keywords: secretion ; cell membrane ; calcium channels ; membrane fusion ; phosphoproteins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: This paper deals with the detailed mechanisms of signal transduction that lead to exocytosis during regulative secretion induced by specific secretagogues in a eukaryotic cell, Paramecium tetraurelia. There are at least three cellular compartments involved in the process: (I) the plasma membrane, which contains secretagogue receptors and other transmembrane proteins, (II) the cytoplasm, particularly in the region between the cell and secretory vesicle membranes, where molecules may influence interactions of the membranes, and (III) the secretory vesicle itself.The ciliated protozoan Paramecium tetraurelia is very well suited for the study of signal transduction events associated with exocystosis because this eukaryotic cell contains thousands of docked secretory vesicles (trychocysts) below the cell membrane which can be induced to release synchronously when trioggered with secretagogue. This ensures a high signal-to-noise ratio for events associated with this process. Upon release the trichocyst membrane fuses with the cell membrane fuses with the cell membrane and the trichocyst content undergoes a Ca2+-dependent irreversible expansion. Secretory mutants are available which are blocked at different points in the signal transduction pathway.Aspects of the three components mentioned above that will be discussed here include (a) the properties of the vesicle content, its pH, and its membrane; (b) the role of phosphorylation/dephosphorylation of a cytosolic 63-kilodalton (kDa)Mr protein in membrane fusion; and (c) how influx of extracellular Ca2+ required for exocytosis may take place via exocytic Ca2+ channels which may be associated with specific membrane microdomains (fusion rosettes).
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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