Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Temperature-Sensitive Behavior of Paramecium caudatum (1977)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 24 (1977), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. The effect of temperature on the behavior of swimming cells of Paramecium caudatum has been investigated by photographic analyses of their tracks in uniform temperature, in temperature gradient, or in temperature changing with time. When the cells were placed in the temperature gradient, the frequency of discontinuous directional changes of cells swimming toward the optimal temperature, the temperature of the culture, was much lower than that of the cells swimming in the opposite direction. This difference in the frequency of directional changes explained the observed accumulation of the cells at - the optimal temperature. When the temperature was suddenly changed toward the optimum, a transient decrease of the frequency of directional changes was observed and when the temperature was changed in the reverse direction, a transient increase of the frequency was noted. This transient response to the temperature change was the origin of the dependence of the frequency of directional changes on the swimming direction in the temperature gradient. Finally, the relation between the magnitude of the transient response and the rate of the temperature change was derived.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1977.tb01018.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Effects of cyclic nucleotides and intracellular Ca on voltage-activated ciliary beating in Paramecium (1990)
    Springer
    Journal of comparative physiology 166 (1990), S. 401-406 
    Details
    ISSN: 1432-1351
    Keywords: Ca2+ ; cAMP ; cGmP ; Ciliary frequency ; Voltage clamp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Coupling mechanisms between ciliary beating and the membrane potential in Paramecium were investigated under voltage clamp applying intracellular pressure injection of cAMP, cGMP and Ca-EGTA buffer. Ciliary responses following step changes in membrane potential were recorded by high-speed video on magnetic tape. 2. Injections of cAMP and cGMP up to millimolar concentrations caused no detectable changes in the frequency voltage relationship. A minor effect was that the ciliary reorientation towards the anterior cell end (reversal) tended to be inhibited with depolarization up to 10 mV. 3. Injection of Ca2+ into the cell clamped at the resting potential caused a transient anteriad ciliary reorientation and a simultaneous increase in the beating frequency. 4. Injection of EGTA (to buffer Ca2+ below 10−8 M) was ineffective in relation to frequency for several minutes. After this time, hyperpolarization- and depolarization activated frequency responses of EGTA-injected cells were increasingly inhibited. The ciliary reorientation following depolarization was not affected by EGTA. 5. A posterior contraction of the cell diameter was noticed upon membrane hyperpolarization. The contraction coincided in time with the increase in beating frequency. 6. The results support the view that the voltage-dependent augmentation of the ciliary beating rate is not directly mediated by an intracellular increase in either cAMP or cGMP. 7. The role of Ca2+ as intracellular messenger in the ciliary and somatic compartments is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00204813
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Hyperpolarization-activated inward current associated with the frequency increase in ciliary beating of Paramecium (1992)
    Springer
    Journal of comparative physiology 170 (1992), S. 723-727 
    Details
    ISSN: 1432-1351
    Keywords: Ciliary beating ; Hyperpolarization ; Inward current ; Ca2+
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to study the relationship between the inward Ca current activated by hyperpolarization and the frequency increase in ciliary beating, Paramecium cells were voltage clamped under conditions where K current was suppressed by use of CsCl electrodes and by extracellular tetraethyl ammonium. A 2-s pulse of hyperpolarization from the resting potential activated an inward current consisting of two components, an initial transient current peaking at 0.1–0.2 s (which had been identified as a Ca current) and a subsequent sustained current. The initial component was not associated with the frequency increase because the frequency increase was normally induced even when the peak current was almost completely inhibited by external addition of Ba2+. The second sustained current was closely correlated with the frequency increase. The frequency rose steeply with the sustained current and saturated at −0.6 nA. External addition of La3+ or replacement of Ca2+ by Mg2+ suppressed this current, and at the same time the frequency increase was inhibited. As the amplitude of the sustained current was not changed by deciliation, this current must pass through the somatic membrane. These results suggest that the frequency increase upon hyperpolarization is triggered by the voltage-activated inward current passing through the somatic membrane of the interciliary compartment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00198983
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Localization of photosensitivity inParamecium bursaria (1989)
    Springer
    Journal of comparative physiology 165 (1989), S. 637-641 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Paramecium bursaria was stimulated by a light spot of 10–15 μm diameter, and the photosensitive site was searched by recording responses in swimming behavior and in membrane potential. 2. Local stimulation to the anterior half of the cell caused an avoiding response. 3. Stimulation to the cells deciliated by ethanol treatment elicited a depolarization of the membrane potential. 4. Local stimulation to the anteroventral portion elicited a depolarization, but stimulation to the dorsal side induced no change in the membrane potential. 5. The action spectrum of depolarization elicited by local stimulation to the anteroventral surface showed two main peaks at 420 nm and 560 nm, corresponding to those of light stimulation of the whole cell. 6. It is concluded that a photosensitive site exists on the anteroventral surface ofParamecium, in particular within the oral groove of the cell. This local photosensitivity is discussed with respect to the mating reaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00610995
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    cAMP-mediated inhibitory effect of calmodulin antagonists on ciliary reversal of ParameciumA part of this work was presented as a poster session at the 3rd International Congress on Cell Biology, Tokyo, 1984. (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 154-159 
    Details
    ISSN: 0886-1544
    Keywords: calcium ; protein phosphorylation ; TFP ; Triton-extracted model ; ciliary orientation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To explore possible roles of calmodulin in Ca2+-induced ciliary reversal, we tested the effects of calmodulin antagonists on Triton-extracted models of Paramecium. In the extracted models prepared by the method of Naitoh and Kaneko [Science 176:523-524, 1972], the Ca2+ -induced ciliary reversal was not inhibited by calmodulin antagonists, trifluoperazine (TFP), or 5-chloro-l-naphthalenesulphone amide (W-7). However, in the presence of adenosine 3′,5′-cyclic mono-phosphate (cAMP), whose concentration is below the one that alters the ciliary direction, TFP inhibited ciliary reversal and the models swam forward at 10-5 M Ca2+. When the washing medium in the preparation of the extracted models was replaced with one containing MgCl2, the extracted model showed sensitivity to calmodulin antagonists without addition of cAMP; at 10-5 M Ca2+, 40 μM TFP or 100 μM W-7 inhibited the ciliary reversal and the models swam forward. Such effect of antagonists was abolished by an inhibitor of cAMP-dependent protein kinase. On the other hand, addition of cAMP enhanced the inhibitory effect of antagonists. These results suggest that calmodulin antagonists act to increase the extent of cAMP-dependent protein phosphorylation that inhibits the Ca2+ -induced ciliary reversal.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070207
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Differentiation of rat thymic myoid progenitor cell line established by coculture with human T-lymphotropic virus type-I-producing human T cells (2000)
    Springer
    Cell & tissue research 300 (2000), S. 119-127 
    Details
    ISSN: 1432-0878
    Keywords: Thymic myoid cell Differentiation Myasthenia gravis HTLV-I Thymic selection Autoimmune disease Cell line Rat (F344/DuCrj; WKAH/HkmSlc) Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. A thymus-derived myoid precursor cell line (ST1), which differentiates to myoid cells in the growth arrest condition, was established by the cocultivation of F344 rat thymic cells with human T-lymphotropic virus type-I (HTLV-I)-producing human lymphoid cells. No integration of HTLV-I was detected in ST1 cells by Southern blot hybridization. In a differentiation culture condition such as confluent culture or serum starvation, ST1 cells began to fuse, creating multinuclear giant cells, with the induced expression of MyoD1 and various muscle-specific antigens, including α-sarcomeric actin, skeletal muscle myosin, myoglobin, desmin, and acetylcholine receptor. Ultrastructural investigation revealed that differentiated ST1B cells created aggregates of thick and thin filaments with Z-band-like composition, then formed sarcomeric structures and tubular honeycomb arrays. Finally, these cells spontaneously contracted with a frequency of 0.5–2.0 Hz and synchronized with adjoining cells. Transplantation of ST1B cells into nude mice produced a small tumor nodule, showing clear differentiation to skeletal muscle cells. ST1B cells did not indicate any colony-forming activities in soft agar, demonstrating that ST1B cells retain some of the physiologically normal phenotypes. This rare cell line is promising for use in various physiological and pathological investigations including functional research of thymic myoid cells and the pathological role in autoimmune diseases, as well as animal model experiments of cell therapy related to muscular degenerative disorders or regeneration of injured muscles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004419900174
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...