title: Effects of nitrate on nitrite toxicity to Microcystis aeruginosa.
abstract: The aim of this study was to investigate the effect of nitrate on nitrite toxicity to Microcystis aeruginosa. Short-term uptake experiment revealed nitrate could depress the nitrite active uptake. The long-term experiment of nitrate effects on nitrite toxicity showed a negative relationship between the growth and intracellular nitrite levels of M. aeruginosa. The net nitrite uptake displayed a decline in the range of 0-150 mg NO(3)(-)-NL(-1) and an elevation at 200mg NO(3)(-)-NL(-1), whereas the activities of nitrate reductase (NR) were more sensitive to nitrate than nitrite reductase (NiR). As a result, the total intracellular nitrite levels tended to decrease up to 100 mg NO(3)(-)-NL(-1) then increased at 150-200 mg NO(3)(-)-NL(-1). These results suggested the existence of external nitrate could affect the toxicity of nitrite to alga through changing intracellular nitrite content.
authors.affiliation: College of Environment and Planning, Henan University, Kaifeng 475004, PR China. chenwm_env@yahoo.com.cn
authors.forename: Weimin
authors.initials: W
authors.lastname: Chen
authors.forename: Haibin
authors.initials: H
authors.lastname: Tong
authors.forename: Hao
authors.initials: H
authors.lastname: Liu
mesh_terms: D005068:Eutrophication; D046931:Microcystis / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D050901:Nitrate Reductase / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism*; D009572:Nitrite Reductases / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*
chemical_list: D009566:Nitrates; D009573:Nitrites; D014874:Water Pollutants, Chemical; D009572:Nitrite Reductases; D050901:Nitrate Reductase