Journal:

Article Title: The Sucrose Analog Palatinose Leads to a Stimulation of Sucrose Degradation and Starch Synthesis When Supplied to Discs of Growing Potato Tubers 1

doi:

Figure Lengend Snippet: Addition of palatinose affects the metabolism of 14C-Suc by potato tuber slices. Freshly cut slices of growing potato tubers were incubated for 2 h in the presence of 20 mm [U-14C]Suc (specific activity 1.4 kBq/μmol) with and without addition of 5, 20, or 100 mm palatinose, before they were washed and extracted to determine label distribution. A, [14C]Suc absorbed by the tissue; B, percentage of the absorbed label that is metabolized to other compounds. Incorporation of 14C into starch (C), phosphate ester (D), organic acids (E), and amino acids (F) is expressed as a percentage of the label metabolized. The specific activity of the hexose phosphate pool (G) was estimated by dividing the label retained in the phosphate ester pool by the summed carbon of the hexose phosphates (see Fig. ​Fig.2N).2N). The values were corrected by dividing by 2 to give the mean specific activity during the course of the 2 h. The absolute fluxes to starch (H), glycolysis (I), and the summed fluxes to starch and glycolysis (K) were calculated using the specific activity of the hexose-phosphate pool. The results are means ± se (n = 4).

Article Snippet: Labeling Experiments Tuber discs (diameter of 8 mm, thickness of 2 mm) were cut directly from growing tubers attached to the fully photosynthesizing mother plant, washed three times with 10 m m MES [2-( N -morpholino) ethane sulfonic acid]-KOH (pH 6.5), and were then incubated (eight discs in a volume of 4 mL in a 100-mL Erlenmeyer flask shaken at 90 rpm) for 2 h in 20 m m Suc including 1.4 KBq μmol −1 U-[ 14 C]Suc or 2 m m Glc including 1.4 KBq μmol −1 U-[ 14 C]Glc (Amersham-Buchler, Freiburg, Germany) and supplementary respiratory substrate as described in the text.

Techniques: Incubation, Activity Assay

Journal:

Article Title: The Sucrose Analog Palatinose Leads to a Stimulation of Sucrose Degradation and Starch Synthesis When Supplied to Discs of Growing Potato Tubers 1

doi:

Figure Lengend Snippet: Metabolite and nucleotide levels in tuber slices incubated with 0, 5, 20, or 100 mm palatinose for 2 h, in parallel to the slices used in Figure ​Figure1.1. A, Suc; B, Glc; C, Fru; D, UDP-Glc; E, UTP; F, UDP; G, UTP/UDP ratio; H, PPi; I, ATP; J, ADP; K, AMP; L, ATP/ADP ratio; M, energy charge; N, hexose phosphates; O, 3-PGA; and P, pyruvate. The results are means ± se (n = 4).

Article Snippet: Labeling Experiments Tuber discs (diameter of 8 mm, thickness of 2 mm) were cut directly from growing tubers attached to the fully photosynthesizing mother plant, washed three times with 10 m m MES [2-( N -morpholino) ethane sulfonic acid]-KOH (pH 6.5), and were then incubated (eight discs in a volume of 4 mL in a 100-mL Erlenmeyer flask shaken at 90 rpm) for 2 h in 20 m m Suc including 1.4 KBq μmol −1 U-[ 14 C]Suc or 2 m m Glc including 1.4 KBq μmol −1 U-[ 14 C]Glc (Amersham-Buchler, Freiburg, Germany) and supplementary respiratory substrate as described in the text.

Techniques: Incubation