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  • Book
    Michael Baumann, Mechthild Krause, Nils Cordes, editors.
    Contents:
    Molecular Radiobiology: Hypoxia
    Molecular Targeting of Growth Factor Receptor Signaling
    Molecular Targeting of Cell Adhesion Molecules
    Tumor Pathophysiology
    DNA Repair
    Cancer Stem Cells
    Normal Tissue. Biomarkers/Personalized Radiation Oncology: EGFR and other RTKs
    HPV
    Hypoxia
    Study design for Biomarker research in radiation oncology
    Gene expression/system biology. Molecular Imaging in Radiation Oncology:FMISO as a biomarker for clinical radiation oncology
    FDG and beyond
    Molecular imaging techniques beyond PET.
    Digital Access Springer 2016
  • Book
    por SELA (Sistema Económico Latinoamericano).
    Print 1987
  • Article
    Villadsen IS, Michelsen O.
    J Bacteriol. 1977 Apr;130(1):136-43.
    The ribonucleoside triphosphate, deoxyribonucleoside triphosphate, 3' -diphosphate guanosine 5' -diphosphate (ppGpp), and 5-phosphoribosyl 1-pyrophosphate (PRPP) pools in Escherichia coli B were determined by thin-layer chromatography during changing conditions to ammonium starvation. The intracellular concentrations of all nucleotides were found to change in a well-defined order several minutes before andy observed change in the optical density of the culture. The levels of purine nucleoside triphosphates (adenosine 5' -triphosphate [CTP], dCTP) and uridine nucleotides (uridine 5' -triphosphate, deoxythymidine 5'-triphosphate). The deoxyribonucleotides thus behaved as the ribonucleotides. The levels of ppGpp increased 11-fold after the decrease in uridine nucleotides, when the accumulation of stable ribonucleic acid (RNA) stopped. The level of the nucleotide pool did not stabilize until 30 min after the change in optical density. The pool of dGTP dropped concomitantly with the pool of CTP. The nucleotide precursor PRPP exhibited a transient increase, wtih maximum value of four times the exponential levels at the onset of starvation. Apparently the cell adjusts early to starvation by reducing either the phosphorylating activity or the nucleotide biosynthetic activity. As in other downshift systems, the accumulation of stable RNA stopped before the break in optical density and before the stop in protein accumulation. Cell divisions were quite insensitive to the control mechanisms operating on RNA and protein accumulation under ammonium starvation, since the cells continued to divide for 21 min without any net accumulation of RNA.
    Digital Access Access Options