NH labelling experiment for the determination of the fate of ammonium in seedlings under normoxia and hypoxic stress

Young seedlings (24 h) were fed with 2 mM (NH)SO (99% N atom excess) for 2, 10, and 24 h. Results are the mean of three replicates, corresponding to N atom excess in glutamate, alanine, aspartate, glutamine (single and double labelled), and asparagine (single and double labelled) (% N-amino acids) and the amounts of newly synthesized amino acids during the labelling period, expressed as nmol N-amino acids per embryo axis. Values followed by different letters, are significantly different according to ANOVA analysis and Newman–Keuls test (α = 5%).<p><b>Copyright information:</b></p><p>Taken from "Concerted modulation of alanine and glutamate metabolism in young seedlings under hypoxic stress"</p><p></p><p>Journal of Experimental Botany 2008;59(9):2325-2335.</p><p>Published online 26 May 2008</p><p>PMCID:PMC2423662.</p><p></p

NH labelling experiment for the determination of the fate of ammonium in seedlings fed excess ammonium under normoxia or hypoxic stress

Nineteen-hour germinated seedlings were split into two batches and maintained for 5 h either on sterile deionized water or aqueous MSX (5 mM), a glutamine synthetase inhibitor. Young seedlings (24 h) were fed with 30 mM (NH)SO (99% N atom excess) for 2, 10, and 24 h under either normoxia or hypoxic stress conditions. The results are the mean of three replicates, corresponding to N atom excess in glutamate, alanine, aspartate, glutamine (single and double labelled), and asparagine (single and double labelled) (% N-amino acids) and the amounts of newly synthesized amino acids during the labelling period, expressed as nmol N-amino acids per embryo axis. Values followed by different letters, are significantly different according to ANOVA analysis and Newman–Keuls test (α = 5%).<p><b>Copyright information:</b></p><p>Taken from "Concerted modulation of alanine and glutamate metabolism in young seedlings under hypoxic stress"</p><p></p><p>Journal of Experimental Botany 2008;59(9):2325-2335.</p><p>Published online 26 May 2008</p><p>PMCID:PMC2423662.</p><p></p

(a) GDH isoenzyme patterns revealed by activity staining after native PAGE of extracts of seedlings grown under normoxia and hypoxic stress conditions

Young seedlings (24 h) were transferred for 10, 24, or 48 h on 2 mM (NH)SO (control), excess ammonium, 30 mM or 2 mM (NH)SO under hypoxia. At each sampling time, proteins were extracted from embryo axes and separated on a 7% native polyacrylamide gel and stained for NAD-GDH activity. An equal amount of proteins (50 μg) was used for each lane. (b) GDH immunoblot analysis. seeds were germinated for 19 h and seedlings maintained for 21 h on sterile deionized water before proteins were extracted from embryo axes. Heat-denaturated proteins were separated on a 11% SDS–PAGE gel, blotted and reacted with antibodies raised against GDH. Proteins extracted from the leaves of 2-month-old plants were used for comparison.<p><b>Copyright information:</b></p><p>Taken from "Concerted modulation of alanine and glutamate metabolism in young seedlings under hypoxic stress"</p><p></p><p>Journal of Experimental Botany 2008;59(9):2325-2335.</p><p>Published online 26 May 2008</p><p>PMCID:PMC2423662.</p><p></p

Changes in activities of GS, NADH-GOGAT, and aminating and deaminating GDH (NADH-GDH and NAD-GDH, respectively) in seedlings under normoxia and hypoxic stress conditions

Young seedlings (24 h) were sampled at various times throughout post-germination growth and the enzyme activities measured in embryo axes. Among these activities, GS activity was expressed as nmol/γ-glutamyl hydroxamate (GHM)/min/embryo axis (). Results are the mean ±SE of three replicates.<p><b>Copyright information:</b></p><p>Taken from "Concerted modulation of alanine and glutamate metabolism in young seedlings under hypoxic stress"</p><p></p><p>Journal of Experimental Botany 2008;59(9):2325-2335.</p><p>Published online 26 May 2008</p><p>PMCID:PMC2423662.</p><p></p