[Effects of different iron concentrations on the growths of a unicellular strain and a colonial strain of Microcystis aeruginosa].
We investigated the growth, photosynthetic efficiency, siderophore production and iron accumulation of two strains of M. aeruginosa, a unicellular strain M. aeruginosa PCC7806 and a colonial strain M. aeruginosa XW01, under iron-limited and iron-replete conditions. The identities of ITS and fur gene sequences of two strains were 95% and 98% respectively.That implied the two strains should be close relatives. Results showed the growths of two strains were severely inhibited under an iron-limited condition. The unicellular strain died in 6 days,whereas the colonial strain could maintain a weak growth in 10 days under the iron-limited condition. PSII maximum light energy transformation (Fv/Fm) of the colonial strain and the unicellular strain were 0.182 +/- 0.014 and 0.160 +/- 0.017, respectively. The colonial strain displayed a higher photosynthetic oxygen evolution than the unicellular strain. Two strains could produce siderophores, which were hydroxamate type. The colonial strain produced more siderophores than unicellular strain under the iron-limited condition.Iron contents of two strains were less than 1/3 cultured in the iron-limited condition than in iron-replete condition, but no obvious difference appeared between the two strains. Our result demonstrated that the colonial strain have a stronger endurance than unicellular strain under the iron-limited condition. As two strains had almost same abilities of iron accumulation, the other physiological mechanisms in the unicellular strain should be more sensitive to lower iron level.
Life Sciences College, Nanjing Normal University, Nanjing 210046, China. polly84@sohu.com
Yu-wen
YW
Wang
Jian-hong
JH
Li
Lu
L
Fu
Min
M
Wu
Yong-ping
YP
Weng
Yao-ming
YM
Zhou
D004305:Dose-Response Relationship, Drug; D005068:Eutrophication / Q000187:drug effects*; D005618:Fresh Water / Q000032:analysis; D007501:Iron / Q000378:metabolism / Q000494:pharmacology*; D046931:Microcystis / Q000145:classification* / Q000187:drug effects / Q000254:growth & development*; D010788:Photosynthesis / Q000187:drug effects; D017262:Siderophores / Q000378:metabolism
D017262:Siderophores; D007501:Iron