| | 2 | Author
| N. Orbert, A. Dencher, Eilo Hildebrand | Requires cookie* | | | Title
| Sensory Transduction in Halobacterium halobium: Retinal Protein Pigment Controls UV-Induced Behavioral Response  | | | | Abstract
| Both photosystems, PS 370 and PS 565, controlling behavioral responses in H alobacterium halo-bium [E. Hildebrand and N. Dencher, Nature 2 5 7 ,4 6 — 48 (1975)] are reversibly inhibited when bacteria are grown in the presence o f 1 mM nicotine which is known to block biosynthesis o f reti nal. Photobehavior can be restored within som e minutes to hours by adding retinal to nicotine-treated bacteria, PS 370 thereby reappearing earlier than PS 565. The reconstitution rate depends on the concentration and on the kind o f retinal isomers applied. A \\-trans retinal is m ost effective. PS 370 becomes fully sensitive if reconstituted in the presence o f nicotine. This rules out the possi bility that the alkaloid may directly inhibit steps o f signal transmission follow ing photoreception. The action spectrum o f PS 370 regenerated with retinal alone o f H. h., strain RjLg (a mutant deficient in carotenoids), fails to show all secondary peaks around 450 nm which in strain Rj occur besides the prominent maximum at 370 nm. A ddition o f carotenoids (m ainly a-bacterioruberin) to reconstituted cells o f R ,L3 restores the sensitivity in that spectral region. Carotenoids or flavin solely added to nicotine-treated bacteria cannot restore photobehavior. We conclude that the active pigm ent o f PS 370, which m ediates the photophobic response to increase o f light intensity (step-up response), represents a retinal protein com plex and that carote noids participate in photoreceptor function as accessory pigments. The biochem ical relation o f the UV-absorbing retinal protein com plex to bacteriorhodopsin is discussed. | | | |
Reference
| Z. Naturforsch. 34c, 841 (1979); received June 5/July 6 1979 | | | |
Published
| 1979 | | | |
Keywords
| Bacteria, Photophobic Response, Bacteriorhodopsin, Carotenoids, Accessory Pigment | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/34/ZNC-1979-34c-0841.pdf | | | | Identifier
| ZNC-1979-34c-0841 | | | | Volume
| 34 | |
| 3 | Author
| Karl-JosefK. Unert, Peter Böger | Requires cookie* | | | Title
| Influence of Bleaching Herbicides on Chlorophyll and Carotenoids | | | | Abstract
| Over 24 and 48 hour cultivation periods the influence of SAN 9789 (norflurazon), EMD-IT 5914 (difunon) and fluridone on growth, photosynthetic oxygen evolution and pigment content of the green alga Scenedesmus acutus was determined. Four effects were observed: a) Both carotenoid and chlorophyll formation were inhibited. b) Carotenoids were destroyed in the presence of air, but not nitrogen. The level of chlorophyll, however, did not change. c) ß-(and a-) carotene was markedly decreased in the presence of oxygen. d) Photosynthetic oxygen evolution was decreased with the disappearance of carotenoids. These effects, which are accompanied by reduced growth, are believed to represent primary herbicidal modes of action. The decrease of oxygen evolution is not due to a direct inhibition of photosynthetic electron transport by the herbicides applied. | | | |
Reference
| Z. Naturforsch. 34c, 1047 (1979); received June 30 1979 | | | |
Published
| 1979 | | | |
Keywords
| Bleaching Herbicides, Algae, Scenedesmus acutus, Carotenoids, Chlorophyll, Air/Nitrogen Gassing | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/34/ZNC-1979-34c-1047.pdf | | | | Identifier
| ZNC-1979-34c-1047 | | | | Volume
| 34 | |
|
