Iron limitation results in induction of ferricyanide reductase and ferric chelate reductase activities in Chlamydomonas reinhardtii |
| |
Authors: | Jaret A Lynnes Tina L M Derzaph Harold G Weger |
| |
Institution: | (1) Department. of Biology, University of Regina, Regina, SK, S4S 0A2, Canada, CA |
| |
Abstract: | The green alga Chlamydomonas reinhardtii Dangeard CW-15 exhibited very low rates of plasma-membrane Fe(III) reductase activity when grown under Fe-sufficient conditions.
After switching the medium to an Fe-free formulation, both ferricyanide reductase and ferric chelate reductase activities
rapidly increased, reaching a maximum after 3 d under iron-free conditions. Both of the Fe(III) reductase activities increased
in parallel over time, they exhibited similar K
m values (approximately 10 μM) with respect to Fe(III), displayed the same pH profile of activity, and both exhibited the same
degree of light stimulation which could be inhibited by 3-(3′,4′-dichlorophenyl)-1,1-dimethylurea (DCMU). Furthermore, ferricyanide
competitively inhibited ferric chelate reduction by iron-limited cells. These results indicate that both Fe(III) reductase
activities were mediated by the same iron-limitation-induced plasma-membrane reductase. No evidence was found for the presence
of Fe(III)-reducing substances in the culture medium, or for the involvement of active oxygen species in the process of Fe(III)
reduction. Chlamydomonas reinhardtii appears to respond to iron limitation in a manner similar to Strategy I higher plants.
Received: 24 June 1997 / Accepted: 2 August 1997 |
| |
Keywords: | Key words:Chlamydomonas (Fe limitation) Ferric chelate reductase Ferricyanide reductase Iron limitation |
本文献已被 SpringerLink 等数据库收录! |
|