[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.
Wang
Yu-wen
YW
Life Sciences College, Nanjing Normal University, Nanjing 210046, China. polly84@sohu.com
Li
Jian-hong
JH
Fu
Lu
L
Wu
Min
M
Weng
Yong-ping
YP
Zhou
Yao-ming
YM
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