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
    Adenine nucleotide metabolism in heat-synchronized Tetrahymena (1975)
    Springer
    Molecular and cellular biochemistry 7 (1975), S. 187-194 
    Details
    ISSN: 1573-4919
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary The metabolism of acid soluble adenine nucleotides in heat-synchronizedTetrahymena pyriformis GL has been studied. In addition, the effect of the synchronizing temperature (34 °C) on adenine nucleotide metabolism in heat-synchronized cells has been determined. In cells induced to divide synchronously through heat treatment (cyclic pulses of 34 °C for 30 min alternating with a 30 min recovery period at 28 °C) variations occurred in the levels of adenine nucleotides when samples of cells were analysed at the end of the last thermal period and at various times preceding the first synchronous cell division. The specific activities of the adenine nucleotides were found to be significantly higher during a pulse label period performed at the end of the last thermal period than at any time during the subsequent synchronous division cycle. The synchronizing temperature was found to partially deplete the intracellular stores of ATP in heat synchronized cells. This decrease was reversible with ATP levels recovering after 15 min of incubation at 28 °C. Fluctuations in the levels and specific activities of the adenine nucleotides are discussed in their relation to macromolecular synthesis and the cell cycle inTetrahymena.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01731408
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Cytoskeletal function of cortical microtubules in the ciliateColpoda (1981)
    Springer
    Protoplasma 108 (1981), S. 29-38 
    Details
    ISSN: 1615-6102
    Keywords: Ciliate ; Colpoda ; Cytoskeleton ; Hydrostatic pressure ; Microtubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The cytoskeletal function of cortical microtubular structures is explored by high-pressure treatment of the ciliated protozoonColpoda cucullus. This ciliate has two regions of form asymmetry which are apparently maintained by microtubules, namely the somatic groove and the right oral lip. Pressure induced changes in cellular morphology and motility were found to be a function of the magnitude of pressure and duration of compression. Cells exposed to 5,000 psi for 25 minutes, 7,500 psi for 12 minutes, and 10,000 psi for 3 minutes are quiescent and acquire a rounded shape. Observation by electron microscopy of cells exposed to 5,000 psi for 25 minutes indicates that the disappearance of the somatic groove and eversion of the oral apparatus are coincident with the disassembly of the microtubular rootlets in the groove and the supraepiplasmic microtubules in the right oral lip. Other changes accompanying the pressure-induced disassemblies include the reduction in numbers of overlapping microtubular ribbons in the cortical ridges and the appearance of cortical granular accumulations. The essential role in form-maintenance played by microtubular components is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276881
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Temperature-pressure experiments on amoeba prodteus; plasmagel structure in relation to form and movementSupported by grant C807 from the National Cancer Institute. (1954)
    Philadelphia : Wiley-Blackwell
    Journal of Cellular and Comparative Physiology 44 (1954), S. 211-232 
    Details
    ISSN: 0095-9898
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1030440206
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Cell cycle changes in water properties in sea urchin eggs (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 133 (1987), S. 14-24 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study concerned changes in the motional properties of cellular water during the first cell cycle of fertilized sea urchin eggs (Lytechinus variegatus). There was a significant decrease in proton NMR T1 relaxation time and in cytoplasmic ice crystal growth during mitosis and a significant increase in T1 time and cytoplasmic ice crystal size during cleavage. This was not caused by egg water content changes as reflected by egg volume measurements. Removal of both the fertilization membrane and the hyaline layer shortly after fertilization did not alter the pattern of T1 time changes at mitosis and cleavage as compared to whole eggs; thus, the pattern of T1 time changes was attributed to intracellular events. Treatment of fertilized eggs with cytochalasin B, an inhibitor of actin polymerization, did not block the fall in T1 time at mitosis, but did block cytokinesis and the increase in T1 time, which normally occurred at cleavage. A significant pattern of actin disassembly and reassembly at mitosis and cytokinesis was found by studies on the total amount of monomeric actin (G actin) using the DNase I assay. This led to the hypothesis that the observed changes in T1 time and ice crystal size during the first cell cycle were due to the depolymerization and polymerization of cytoplasmic actin. To test this, the effect of the in vitro polymerization of purified actin on the T1 time and on ice crystal growth was examined. It was concluded that changes in the T1 time and ice crystal growth upon polymerization of actin in vitro resembled the changes seen in vivo. These results suggest that changes in the motional properties of cytoplasmic water during the first cell cycle are due, at least in part, to the state of polymerization of cytoplasmic actin.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041330103
    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...