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Calcium Is Involved in Photomovement of Cyanobacterium Synechocystis sp. PCC 6803 ¶
Author(s) -
Moon YoonJung,
Park Young Mok,
Chung YoungHo,
Choi JongSoon
Publication year - 2004
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.2004.tb09865.x
Subject(s) - egta , motility , trifluoperazine , calcium , calmodulin , biochemistry , biophysics , chemistry , biology , microbiology and biotechnology , organic chemistry
The unicellular cyanobacterium Synechocystis sp. PCC 6803 (Syn6803) exhibits photomovement through gliding motility. For a better understanding of photomovement in Syn6803, we examined the effects of Ca 2+ on photoorientation and motility using a computer‐assisted videomicroscope motion analysis system. When calcium ion was chelated from the basic motility medium by adding 0.5 m M ethylene glycol‐bis‐(β‐aminoethyl ether)‐ N, N, N', N' ‐tetraacetic acid (EGTA), the photoorientation was completely inhibited, whereas the gliding motility remained approximately 70% of the control. Photoorientation impaired by EGTA was nearly recovered within 30 min upon addition of 1 m M Ca 2+ . The recovery of photoorientation by Ca 2+ was mimicked by either Mn 2+ or Mg 2+ but not by Ba 2+ or Sr 2+ . Lanthanum ion at 10 μ M completely inhibited both phototactic orientation and gliding motility of Syn6803. Furthermore, pimozide (voltage‐gated L‐type calcium channel inhibitor), orthovanadate (calcium efflux blocker) and A23187 (calcium ionophore) partially inhibited phototactic orientation and gliding motility. Interestingly, photoorientation was prevented with increasing concentrations of calmodulin antagonist such as trifluoperazine (TFP) and chlorpromazine, but gliding motility was inhibited in proportion to the concentration of TFP. The results we present strongly indicate that Ca 2+ plays a significant role in regulating the photomovement of Syn6803.