title: Endosulfan induced biochemical changes in nitrogen-fixing cyanobacteria.
abstract: Pesticide contamination in aquatic ecosystem including paddy fields is a serious global environmental concern. Cyanobacteria are also affected by pesticides as non- target organism. For better exploitation of cyanobacteria as biofertiliser, it is indispensable to select tolerant strains along with understanding of their tolerance. Three cyanobacterial strains viz. Aulosira fertilissima, Anabaena variabilis and Nostoc muscorum were studied for their stress responses to an organochlorine pesticide 'endosulfan' with special reference to oxidative stress, role of proline and antioxidant enzymes in endosulfan induced free radical detoxification. Reduction in growth, photosynthetic pigments and carbohydrate of the test microorganisms were accompanied with increase in their total protein, proline, malondialdehye (MDA), superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) in higher endosulfan doses. Increased amount of MDA is indicative of formation of free radicals, while increased level of CAT, APX, SOD and proline indicated their involvement in free radical scavenging mechanism. In lower concentrations, test pesticide showed increase in photosynthetic pigments. Order of tolerance was Nostoc muscorum>Anabaena variabilis>Aulosira fertilissima.
authors.affiliation: Department of Biosciences, Jamia Millia Islamia Central University, New Delhi -110025, India. satya3369@gmail.com
authors.forename: Satyendra
authors.initials: S
authors.lastname: Kumar
authors.forename: Khalid
authors.initials: K
authors.lastname: Habib
authors.forename: Tasneem
authors.initials: T
authors.lastname: Fatma
mesh_terms: D060387:Ascorbate Peroxidases; D001426:Bacterial Proteins / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D000458:Cyanobacteria / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D017753:Ecosystem; D004726:Endosulfan / Q000633:toxicity*; D016166:Free Radical Scavengers / Q000378:metabolism; D007306:Insecticides / Q000633:toxicity*; D008315:Malondialdehyde / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D010544:Peroxidases / Q000378:metabolism; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism; D011392:Proline / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D016166:Free Radical Scavengers; D007306:Insecticides; D045322:Photosynthetic Reaction Center Complex Proteins; D008315:Malondialdehyde; D011392:Proline; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D004726:Endosulfan