Library

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
  • 1980-1984  (4)
  • 1935-1939
  • 1983  (2)
  • 1980  (2)
  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Biochemistry 19 (1980), S. 5814-5818 
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 34 (1980), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: A sensitive radioisotopic assay has been used to examine the kinetic properties and regulation of biosynthesis of glutamine synthetase in C-6 glioma cultures. The Km values for glutamate, MgATP, and ammonium ion were 5mM, 14 mM, and 0.042 mM, respectively, when measured at the pH optimum of 7.2. There was an absolute requirement for a divalent metal ion, with 15 mM- Mg2+ being the preferred ion at pH 7.2. Activity was completely inhibited after 30 min with 8 mM-L-methionhe sulfoximine. The addition of 1 μM-cortisol to C-6 cultures caused a two to threefold increase in glutamine synthetase specific activity over a 96-h period, while dexamethasone at the same concentration elevated the level some 7-10-fold. This was specific for glucocorticoids, as other steroid hormones or catecholamines did not significantly affect glutamine synthetase specific activity. Cycloheximide (30 μM) or actinomycin D (0.01 μg/ml) blocked the hormone response. The continued presence of hormone was required in order to maintain an elevated enzyme level. The results suggest that glucocorticoids act to induce glutamine synthetase by stimulating new enzyme synthesis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 35 (1983), S. 82-86 
    ISSN: 1432-0827
    Keywords: Osteoclasts ; Bone marrow culture ; Hydrocortisone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The generation of osteoclasts in cultures of cat bone marrow was completely inhibited for 4 weeks with 10−6M hydrocortisone (HC) and partially inhibited with 10−7 to 10−9M in a dose-dependent fashion. This effect was completely reversible when cultures were exposed for only 2 weeks to 10−9 or 10−8M HC. However, cultures in which higher concentrations (10−7 to 10−5M) were maintained for the same period did not show complete recovery in terms of numbers of osteoclasts and number of nuclei per cell after withdrawal of HC, suggesting that precursor cells of osteoclasts were also damaged by HC. To study the effects of HC on osteoclasts already present in the cultures, 10−6M was added to 4-week-old untreated cultures. The number of osteoclasts decreased rapidly and a gross morphological response was also apparent (rounding of the cells leading to detachment from the substratum and inhibition of cell fusion), indicating that the generation as well as the survival of osteoclasts in vitro are sensitive to HC. The morphological changes observed under optical and electron microscopy correspond to those of the reported inactive form of osteoclasts, and suggest that their function may also be altered by HC.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Plant ecology 51 (1983), S. 141-155 
    ISSN: 1573-5052
    Keywords: Correlation matrix ; Dispersion matrix ; Forest model ; Hierarchical structure ; Ordination ; Principal components analysis ; Simulation ; Succession
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A model of a 1/12th ha forest stand, FORET, generated 10 000 years of simulated species succession. Approximately the first third of these results were analyzed by principal component analysis as if they were collected field data to give the trajectory of the community particle in a collapsed species space. The ordination axis orientation was performed on a dispersion matrix and correlation matrix between species. In both cases, however, the eigen vectors were applied to the data matrix which had not been transformed to unit species variance. This facilitated comparison of species dispersion and correlation structure; it emerged they were very different. Correlation structure gave large weights to understory species while dispersion emphasized the dominant overstory species. This implies a decomposition of simulated stand behavior into overstory and understory, even though such decomposition was not formally built into the model. This decomposition would seem to pertain to real vegetation. Principal component analysis was able to express insightful differences between data structure with and without the unit variance transformation implicit in the correlation matrix. This flexibility of the ordination method proved valuable in uncovering unsuspected ordering principles in the model. Complex simulated data allow the ordination technique to demonstrate its capacity to generate new hypotheses, which hypotheses can then be simply validated by a return to the structure of the model but with the hindsight of the analysis. The generation of new hypotheses is not possible if the simulation is of a simple coenocline; on the other hand, ordination of test field data does not allow the simple validation of new hypotheses, for in the field there is not a defined algorithm to which the researcher can return.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...