title: Action of an algicide from a cyanobacterium, Oscillatoria laetevirens, on photosystem II.
abstract: Oscillatoria laetevirens produces an algicide, named oscillatorin (OS), which inhibits growth of higher plants. Effect of purified oscillatorin and some 'urea-triazine type' herbicides was studied on photosystem II activity and composition of pigment protein complex in spinach thylakoid membrane. For oscillatorin the I50 at 10 microg chlorophyll concentration, inhibitor constant (Ki), specific binding sites and Hill coefficient were calculated to be 1.45, 0.15, 2.3 and 0.2 microM respectively. Metribuzin and oscillatorin affected towards the donor side and brought about identical changes in polypeptide composition of PSII complex. Further, metribuzin and atrazine exerted antagonistic and synergistic responses on oscillatorin action. Some of these parameters were also studied on weed plants to assess upon the weedicidal potential of oscillatorin.
authors.affiliation: Department of Biological Sciences, R. D. University, Jabalpur, India.
authors.forename: R
authors.initials: R
authors.lastname: Shrivastava
authors.forename: S
authors.initials: S
authors.lastname: Ray
authors.forename: S N
authors.initials: SN
authors.lastname: Bagchi
mesh_terms: D000458:Cyanobacteria / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D006540:Herbicides / Q000494:pharmacology*; D045342:Light-Harvesting Protein Complexes; D009930:Organic Chemicals; D045322:Photosynthetic Reaction Center Complex Proteins / Q000037:antagonists & inhibitors / Q000187:drug effects*; D045332:Photosystem II Protein Complex
chemical_list: D006540:Herbicides; D045342:Light-Harvesting Protein Complexes; D009930:Organic Chemicals; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; C456859:oscillatorin