| 1 | Author
| Gerhard Sandmann, IanE. Clarke, PeterM. Bramley, Peter Böger | Requires cookie* | | Title
| Inhibition of Phytoene Desaturase — the Mode of Action of Certain Bleaching Herbicides  | | | Abstract
| Assay systems have been developed in order to differentiate betw een the m odes o f action o f certain bleaching herbicides. These include inhibition o f chlorophyll or carotenoid biosynthesis, and initiation o f pigment degradation. H erbicidal com pounds with phytoene desaturase as their primary target site were investigated in a cell-free carotenogenic system from Aphanocapsa. In a comparative study, the structural prerequisites for inh ib ition o f phytoene desaturase were estab lished for both benzophenone analogs and various m -phenoxybenzam ides. This inhibitory action o f the latter compounds is enhanced by lipophilic groups with certain steric properties. | | |
Reference
| Z. Naturforsch. 39c, 443 (1984); received N ovem ber 1 1983 | | |
Published
| 1984 | | |
Keywords
| Bleaching Herbicides, Cell-Free System, Carotene Biosynthesis, P hytoene Desaturase, Inhibitors | | |
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| default:Reihe_C/39/ZNC-1984-39c-0443.pdf | | | Identifier
| ZNC-1984-39c-0443 | | | Volume
| 39 | |
2 | Author
| M. Anfred Steingraber, Hanns Frohnm, Rüdiger Ham | Requires cookie* | | Title
| Light-Dependent Sucrose Synthesis in Cell-Free (Reconstituted) Lysates of Evacuolated Mesophyll Protoplasts  | | | Abstract
| Oat mesophyll protoplasts were evacuolated by centrifugation on a Percoll gradient and used as starting material for establishing a functional cell-free system. For this purpose evacuolated protoplasts were osm otically lysed. From the resulting homogenate a cytosolic fraction was obtained by silicon oil filtration. This fraction was used to dilute preparations o f lysed evacu olated protoplasts in order to reduce the number o f organelles per volume cytosol. The latter was necessary to increase light-dependent oxygen evolution o f the cell-free system. The result ing kind o f "reconstituted" system showed light-dependent sucrose formation (about 100 nmol (mg Chi)-1 • h r 1) with bicarbonate as the only substrate. As this property depends on a functional interaction o f chloroplast and cytosolic reactions, this cell-free system appeared to perform essential steps o f partitioning o f C 0 2 between starch and sucrose. Addition o f about 12 (im fructose 2 ,6 -bisphosphate, an inhibitor o f fructose 1,6 -bisphosphatase and an activator o f the PPi-dependent fructose 6 -phosphate phosphotransferase, caused sucrose degradation in the light. Thus, this cell-free system allows both the study o f cytosolic enzyme activities under quasi in vivo conditions and the manipulation o f cellular reaction sequences by plasma mem brane-impermeable compounds. | | |
Reference
| Z. Naturforsch. 45c, 217 (1990); received January 11 1990 | | |
Published
| 1990 | | |
Keywords
| Avena sativa, Cell-Free System, Evacuolation, Mesophyll Protoplasts, Sucrose Synthesis | | |
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| default:Reihe_C/45/ZNC-1990-45c-0217.pdf | | | Identifier
| ZNC-1990-45c-0217 | | | Volume
| 45 | |
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