title: Genetically modified cyanobacterium Nostoc muscorum overproducing proline in response to salinity and osmotic stresses.
abstract: In the parent Nostoc muscorum an active proline oxidase enzyme is required to assimilate exogenous proline as a fixed nitrogen source. Cyanobacterial mutants, resistant to growth inhibitory action of proline analogue L-azetidine-2-carboxylate (Ac-R), were deficient in proline oxidase activity, and were over-accumulators of proline. Proline over-accumulation, resulting either from mutational acquisition of the Ac-R phenotype, or from salinity-induced uptake of exogenous proline, confirmed enhanced salinity/osmotic tolerance in the mutant strain. The nitrogenase activity and photosynthetic O 2 evolution of the parent were sensitive to both salinity as well as osmotic stresses than of Ac-R mutant strain. In addition, the mutation to Ac-resistant phenotype showed no alteration in salinity inducible potassium transport system in the cyanobacterium.
authors.affiliation: Department of Botany, Swami Vivekanand Government College, Raisen 464 551, India. santoshbhargava@hotmail.com
authors.forename: Santosh
authors.initials: S
authors.lastname: Bhargava
mesh_terms: D001383:Azetidinecarboxylic Acid / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D009154:Mutation; D050502:Nostoc muscorum / Q000235:genetics / Q000378:metabolism; D030781:Organisms, Genetically Modified; D009997:Osmotic Pressure; D011188:Potassium / Q000378:metabolism; D011392:Proline / Q000378:metabolism*; D011394:Proline Oxidase / Q000378:metabolism; D012492:Salts / Q000378:metabolism*; D013395:Sucrose / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D012492:Salts; D013395:Sucrose; D001383:Azetidinecarboxylic Acid; D011392:Proline; D011394:Proline Oxidase; D011188:Potassium