title: Physiological and biochemical alterations in Anabaena 7120 under iron stress.
abstract: Various physiological and biochemical process like growth, NO3- -uptake, nitrate reductase, glutamine synthetase and ATPases (Mg2+ and Ca2+ dependent) in the cyanobacterium Anabaena 7120 were observed under iron stress. Growth was found to be maximum in 50 microM Fe3+ added cells however, 20 microM Fe3+ (the Fe3+ concentration generally used for routine culturing of cyanobacterial cell in Chu 10 medium) incubation resulted in lower growth. Fe3+ starvation on the other hand showed very poor growth up to 4th day but once the growth started it reached at significant level on 7th day. Higher Fe3+ concentration reflected reduced growth with lethality at 500 microM Fe3+. Chlorophyll a fluorescence under Fe3+ stress reflected almost the similar results as in case of growth. However, the pigment was found to be more sensitive as compared to protein under Fe3+ stress. Similar results have been observed in case of NO3-uptake with only 80% reduction in nutrient uptake in 500 microM Fe3+ incubated cells. Nitrate reductase activity was lower in Fe3+ starved cells as compared to significant enzyme activity in 20 and 50 microM Fe3+ incubated cells. Similar to nitrate reductase, glutamine synthetase also showed maximum level in 50 microM Fe3+ added cells, however, higher Fe3+ concentration (300-500 microM ) resulted in reduced enzymatic activity. Glutamine synthetase activity was less sensitivity as compared to nitrate reductase activity under Fe3+ stress. ATPase (Mg2+ and Ca2+ dependent) always showed higher level with increasing Fe3+ concentration.
authors.affiliation: Institute of Microbiology and Biotechnology, Barkatullah University, Bhopal 462 026, India.
authors.forename: R K
authors.initials: RK
authors.lastname: Saxena
authors.forename: P K
authors.initials: PK
authors.lastname: Pandey
authors.forename: P S
authors.initials: PS
authors.lastname: Bisen
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D017033:Anabaena / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D007501:Iron / Q000494:pharmacology*; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D013050:Spectrometry, Fluorescence
chemical_list: D009566:Nitrates; D007501:Iron; D009565:Nitrate Reductases; D050901:Nitrate Reductase; D000251:Adenosine Triphosphatases; D005974:Glutamate-Ammonia Ligase