ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
Filter
  • Calcium
  • Springer  (4)
  • American Meteorological Society (AMS)
  • American Association of Petroleum Geologists (AAPG)
  • 1980-1984  (4)
  • 1982  (4)
Collection
Keywords
Publisher
  • Springer  (4)
  • American Meteorological Society (AMS)
  • American Association of Petroleum Geologists (AAPG)
Years
  • 1980-1984  (4)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Equilibrium dialysis and ultrafiltration studies of calcium and phosphate binding by human salivary proteins. Implications for salivary supersaturation with respect to calcium phosphate salts (1982)
    Springer
    Calcified tissue international 34 (1982), S. 531-538 
    Details
    ISSN: 1432-0827
    Keywords: Saliva ; Calcium ; Phosphate ; Ion-binding ; Supersaturation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Previous ultrafiltration studies indicated that up to one-half of the calcium and two-thirds of the phosphate in human salivary secretions may be bound by salivary proteins. Since this binding is an important variable in determining the extent of salivary supersaturation with respect to calcium phosphate salts, and since the amount of binding reported is surprisingly large, calcium and phosphate ion-binding by salivary macromolecules has been reexamined. From experiments using equilibrium dialysis, it was found that (1) the fraction of salivary calcium involved in macromolecular complexes ranges from a few percent for unstimulated secretions, to no more than about 10% for stimulated glandular salivas, and (2) salivary proteins do not bind phosphate ions to any significant extent. These findings, and experiments using an improved ultrafiltration membrane, indicate that the earlier results were artifacts of the ultrafiltration technique. Fractionation of salivary proteins, followed by equilibrium dialysis measurements, showed that the anionic proline-rich proteins and a basic proline-rich glycoprotein are responsible for most of the calcium binding now observed. The finding that macromolecular complexes of salivary calcium and phosphate have been overestimated in the past, leads to the conclusion that salivary calcium and phosphate ion activities in stimulated salivary secretions may be up to 50 to 100% higher than previously thought. Revised values were therefore used to recalculate the degree of salivary supersaturation with respect to calcium phosphate salts. The results indicate that stimulated salivary secretions are supersaturated with respect to dicalcium phosphate dihydrate; this is a substantially greater degree of supersaturation than previously reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411299
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    On the role of calcium in chemotaxis and oscillations of dictyostelium cells (1982)
    Springer
    European biophysics journal 9 (1982), S. 131-136 
    Details
    ISSN: 1432-1017
    Keywords: Chemotaxis ; Calcium ; Oscillation ; Dictyostelium ; Ionophore
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Migration of differentiated cells to a capillary containing cyclic AMP was enhanced in the presence of 1 mM CaCl2 and was virtually absent in the presence of 1 mM EGTA. Furthermore, the cells contracted and extended pseudopods to a capillary filled with the calcium ionophore A 23187. At short distances, migration to the tip of the capillary was observed. The ionophore also induced transient decreases of the optical density of suspended cells indicating changes of cell shape. These findings support the hypothesis that cyclic AMP-binding to cell surface receptors causes a local influx of calcium ions. These in turn lead to an increase of the cytosolic calcium concentration and subsequently to an activation of cell migration. Perturbing pulses of the ionophore induced permanent phase shifts of free-running light scattering oscillations. This result indicates that cytosolic calcium is an intrinsic component of the oscillatory system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00539112
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Tentacle contraction and ultrastructure inDiscophrya collini: The response to cations (1982)
    Springer
    Protoplasma 112 (1982), S. 92-100 
    Details
    ISSN: 1615-6102
    Keywords: Discophrya ; Tentacle contraction ; Cations ; Calcium ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Discophrya collini is a suctorian protozoan with contractile tentacles containing a microtubule-lined canal and microfilaments. The effects of a range of cations on tentacle contraction and ultrastructure have been determined. Treatment with 80 mM CaCl2 and 95 mM MgCl2 causes contraction to 28% and 57% of the control length respectively. Re-extension takes over 4 hours in the culture medium, but CaCl2-treated tentacles are re-extended after a 5 minutes treatment with 10−2 M EDTA or 5 × 10−3 M EGTA. CuCl2 causes a significant contraction at 10−5 M (to 77%); LaCl3 at 10−4 M (to 65%); ZnCl2 at 10−2 M (to 65%), but BaCl2, CoCl2, MnCl2, NiCl2, and SrCl2 cause significant changes only at 10−1 M. The cytoplasm of CaCl2-treated cells contains two forms of membraneous structures when viewed in TEM; that of MgCl2-treated cells reveals granular areas of medium electron density. None of these features are seen in control cells. The microtubules of the tentacle canal appear to be intact upon its retraction into the cell with no change occurring in the numbers or relative positions of the microtubules. The tentacle cortex is wrinkled. It is suggested from this and previous work that tentacle contraction may be mediated by a microfilament-based mechanism, and that calcium may be involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01280219
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The demonstration of calcium in the axonal granules of the peripheral nervous system of male Schistosoma mansoni by X-ray microanalysis (1982)
    Springer
    Cell & tissue research 222 (1982), S. 597-604 
    Details
    ISSN: 1432-0878
    Keywords: Schistosoma mansoni ; Freeze-dried cryosections ; X-ray microanalysis ; Calcium ; Peripheral nervous system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A conspicuous feature of freeze-dried cryosections of male Schistosoma mansoni is the presence of groups of electron-dense granules. X-ray analysis in the TEM of these granules shows them, in comparison with the adjacent cytoplasm, to contain significantly greater amounts of sodium and calcium. In glutaraldehyde-fixed material, these granules have been correlated with the membrane-bounded, electron-dense granules found within the axons of the peripheral nervous system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213857
    Location Call Number Expected 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...