title: Effects of nitrogen forms on the production of cyanobacterial toxin microcystin-IR by an isolated Microcystis aeruginosa.
abstract: A cyanobacterial strain, which produced high content of microcystin-LR (MC-LR) but no microcystin-RR (MC-RR), was isolated from the hypertrophic Dianchi Lake in China and identified as Microcystis aeruginosa DC-1. Effects of nitrogen containing chemicals and trace elements on the growth and the production of MC-LR by this strain were studied. In the presence of bicine, compared with urea and ammonium, nitrate greatly promoted the growth and the production of MC-LR. However, leucine and arginine, which were the constitutional components in the molecular structure of MC-LR or RR, inhibited the production of MC-LR. Iron and silicon up to 10 mg/L had little effects on the growth of M. aeruginosa DC-1, but the production of MC-LR was apparently enhanced. Under all conditions studied here, only MC-LR but no RR was detected within the cells of M. aeruginosa DC-1. Thus, chemical forms of nitrogen, rather than the usually concerned the total nitrogen, and trace elements played important roles in the production of MC toxins during cyanobacterial blooms.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, China.
authors.forename: Hai
authors.initials: H
authors.lastname: Yan
authors.forename: Gang
authors.initials: G
authors.lastname: Pan
authors.forename: Hua
authors.initials: H
authors.lastname: Zou
authors.forename: Lirong
authors.initials: L
authors.lastname: Song
authors.forename: Mingming
authors.initials: M
authors.lastname: Zhang
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D008387:Marine Toxins; D052998:Microcystins; D046931:Microcystis / Q000254:growth & development* / Q000502:physiology; D017672:Nitrogen Compounds / Q000378:metabolism; D010456:Peptides, Cyclic / Q000096:biosynthesis*; D014131:Trace Elements
chemical_list: D000596:Amino Acids; D008387:Marine Toxins; D052998:Microcystins; D017672:Nitrogen Compounds; D010456:Peptides, Cyclic; D014131:Trace Elements; C057862:cyanoginosin LR