Table V.
Labeling of DMSP-ald from [35S]SMM or [35S]DMSP-amine in S. alterniflora
| 35S Precursor | Treatment | Label
Distribution
|
|||
|---|---|---|---|---|---|
| SMM | DMSP-amine | DMSP-ald | DMSP | ||
| kBq | Bq | Bq | kBq | ||
| SMM | Pulse | 69.3 | 936 | 24.1 | 2.44 |
| Pulse-chase | 23.8 | 466 | 8.1 | 13.0 | |
| DMSP-amine | Pulse | –a | 23,400 | 11.8 | 1.41 |
| Pulse-chase | – | 3,990 | 1.1 | 2.74 | |
Pairs of leaf segments were supplied with a pulse of [35S]SMM (77 kBq, 0.99 nmol) or [35S]DMSP-amine (35 kBq, 1.33 nmol) for 3 h, rinsed for 15 s, and then transferred to water for a 9-h chase period. DMSP-ald was analyzed as the corresponding alcohol after reduction with NaBH4 (see Methods); a correction was made for traces of alcohol detectable in controls that were not treated with NaBH4. That more 35S was lost from SMM or DMSP-amine during the chase than appeared in DMSP may be ascribed primarily to efflux of unabsorbed label from the apoplast. The values shown are per pair of segments and have been corrected for recovery. The experiment was repeated, with similar results.
–, Below detection limit (0.05 kBq).