Relationship of energy charge and toxin content of Microcystis aeruginosa in nitrogen-limited or phosphorous-limited cultures.
Effects of nitrogen-limitation and phosphorus-limitation on microcystin (MC) content and energy charge (EC) of the Microcystis aeruginosa were investigated in batch cultures and semi-continuous cultures. In batch cultures, nitrogen-limitation retarded the MC synthesis and phosphorus-limitation had little effects on MC production. The EC remained constant in nitrogen-limited cultures, while it decreased largely when phosphorus was extinct in phosphorus-limited culture. In the semi-continuous cultures, MC production in nitrogen- and phosphorus-limited cultures increased with the increase of dilution rate; however, MC content in phosphorus-limited cultures was more than that in nitrogen-limited cultures. The EC in nitrogen-limited cultures remained constant and in phosphorus-limited cultures increased with the increase of dilution rate. In phosphorus-limited semi-continuous cultures, a direct relationship between EC and MC content was demonstrated. No correlation was observed in nitrogen-limited semi-continuous cultures. Based on the above analysis, a mechanism of nitrogen and phosphorus effect on the MC synthesis was suggested, that the MC synthesis was determined by the combination of necessary enzymes and precursors and EC.
Dai
Ruihua
R
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Liu
Huijuan
H
Qu
Jiuhui
J
Zhao
Xu
X
Ru
Jia
J
Hou
Yining
Y
D001431:Bacteriological Techniques; D004734:Energy Metabolism; D008387:Marine Toxins; D052998:Microcystins / Q000378:metabolism; D046931:Microcystis / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism*
D008387:Marine Toxins; D052998:Microcystins; D010758:Phosphorus; C063855:microcystin RR; C057862:cyanoginosin LR; D009584:Nitrogen