Angaben zur Quelle [Bearbeiten]
| Autor | Klaus-Dieter Schlüter, Karen Frischkopf, Markus Flesch, Stephan Rosenkranz, Gerhild Taimor, Hans Michael Piper |
| Titel | Central role for ornithine decarboxylase in β-adrenoceptor mediated hypertrophy |
| Zeitschrift | Cardiovascular Research |
| Jahr | 1999 |
| Jahrgang | 45 |
| Nummer | 2 |
| Seiten | 410-417 |
| DOI | doi: 10.1016/S0008-6363(99)00351-X |
| URL | http://cardiovascres.oxfordjournals.org/content/45/2/410.full |
Literaturverz. |
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| Fußnoten | nein |
| Fragmente | 2 |
| [1.] Analyse:Aa/Fragment 009 04 - Diskussion Zuletzt bearbeitet: 2013-01-22 21:20:52 Graf Isolan | Aa, Fragment, SMWFragment, Schlüter et al 1999, Schutzlevel, Verschleierung, ZuSichten |
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| Untersuchte Arbeit: Seite: 9, Zeilen: 4-13 |
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| In the case of β-adrenoceptor stimulation, however, RNA elevation is not accompanied by increase in RNA synthesis (Pinson et al., 1993). The mechanism by which β-adrenoceptor stimulation elevates RNA mass seems to be due to a decrease of RNA degradation, which can be mediated by stabilization of RNA by polyamines (Igarashi et al., 1982). Ornithine decarboxylase (ODC) represents the rate-limiting enzyme of polyamine metabolism. ODC is involved in the mechanism by which β-adrenoceptor stimulation elevates cellular RNA mass (Cohen SS., 1998). β-Adrenoceptor-mediated hypertrophy in vivo is also accompanied by induction of ODC (Bartolome et al., 1980).
Bartolome J, Guguenard J, Slotkin TA (1980) Role of ornithine decarboxylase in cardiac growth and hypertrophy. Science 210: 793–794. Cohen SS, Polyamines and the animal cells. In: Cohen SS, editor, A guide to the polyamines, New York: Oxford University Press, 1998, pp. 184–203. Igarashi K, Kakegawa T, Hirose S (1982) Stabilization of 30 S ribosomal subunits of Bacillus subtilis W168 by spermidine and magnesium ions. Biochim Biophys Acta 755:326–331. Pinson A, Schlüter K-D, Zhou XJ, Schwartz P, Kessler-Icekson G and Piper HM (1993) Alpha- and beta-adrenergic stimulation of protein synthesis in cultured adult ventricular cardiomyocytes. J Mol Cell Cardiol 25: 477-490. |
In case of β-adrenoceptor stimulation, however, RNA elevation is not accompanied by an increased 14C-uridine incorporation [7]. That let us conclude that the mechanism by which β-adrenoceptor stimulation elevates RNA mass seems to be due to a decrease of RNA degradation. Since polyamines are known to stabilize RNA [9] this may explain the observed elevation of RNA in the absence of elevated RNA synthesis.
Ornithine decarboxylase (ODC) represents the rate limiting enzyme of the polyamine metabolism. An induction of ODC is causally involved in the mechanism by which β-adrenoceptor stimulation elevates cellular RNA mass [10]. β-Adrenoceptor mediated hypertrophy in vivo is, indeed, accompanied by induction of ODC [5]. [5] Bartolome J, Guguenard J, Slotkin TA. Role of ornithine decarboxylase in cardiac growth and hypertrophy. Science 1980;210:793–794. [7] Pinson A, Schlüter K-D, Zhou XJ, Schwartz P, Kessler-Icekson G, Piper HM. Alpha- and beta-adrenergic stimulation in cultured adult ventricular cardiomyocytes. J Mol Cell Cardiol 1993;25:477–490. [9] Igarashi K, Kakegawa T, Hirose S. Stabilization of 30 S ribosomal subunits of Bacillus subtilis W168 by spermidine and magnesium ions. Biochim Biophys Acta 1982;755:326–331. [10] Cohen SS. Polyamines and the animal cells. In: Cohen SS, editor, A guide to the polyamines, New York: Oxford University Press, 1998, pp. 184–203. |
Wörtliche Übereinstimmung langer Passagen und der Literaturhinweise ohne Kenntlichmachung. |
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| [2.] Analyse:Aa/Fragment 027 10 - Diskussion Zuletzt bearbeitet: 2013-01-23 01:13:51 Graf Isolan | Aa, Fragment, SMWFragment, Schlüter et al 1999, Schutzlevel, Unfertig, Verschleierung |
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| Untersuchte Arbeit: Seite: 27, Zeilen: 10-18, 21-26 |
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| Incorporation of phenylalanine into cells was analysed by exposing cultures to 14C-phenylalanine for 24 hrs and determining the incorporation of radioactivity into the acid-insoluble cell mass. Non-radioactive phenylalanine (0.3mM) was added to the medium to minimize variations in the specific activity of the precursor pool responsible for protein synthesis.
Experiments were terminated by removal of the medium from the cultures. Cells were washed three times with 1 ml of ice-cold PBS. Subsequently, 1 ml of ice-cold 10% (wt/vol) trichloroacetic acid (TCA) was added. Protein precipitation was performed overnight at 4°C. [...] Radioactivity in this acid fraction presented the intracellular precursor pool. The dishes were then washed twice with 1 ml of ice-cold 10% (wt/vol) trichloroacetic acid and a third time with 1 ml of ice-cold PBS. The remaining precipitate in the culture dishes was dissolved in 1 ml of 1N NaOH/0.01% (wt/vol) SDS by incubation at 37°C overnight. |
[Seite 411]
Incorporation of phenylalanine into cells was determined by exposing cultures to L-14C-phenylalanine (0.1 μCi/ml) for 24 h and determination of the incorporation of radioactivity into acid-insoluble cell mass as described before [7]. [Seite 412] [...] Nonradioactive phenylalanine (0.3 mmol/ l) was added to the medium to minimize variations in the specific activity of the precursor pool responsible for protein synthesis. In incorporation studies, experiments were terminated by removal of the supernatant medium from the cultures and washed three times with ice-cold phosphate-buffered saline (PBS; composition in mmol/l: 1.5 KH2PO4 , 137 NaCl, 2.7 KCl, and 1.0 Na2HPO4, pH 7.4). Subsequently, ice-cold 10% (w/v) trichloroacetic acid was added. After storage overnight at 4°C, the acid was removed from the dishes. Radioactivity contained in this acid fraction was taken to present the intracellular precursor pool. The dishes were then washed twice with ice-cold PBS. The remaining precipitate on the culture dishes was dissolved in 1 M NaOH–0.01% (w/v) sodium dodecylsulphate (S.D.S) by an incubation for 2 h at 37°C. |
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