Open AccessHexavalent chromium uptake by sensitive and tolerant mutants of Schizosaccharomyces pombe
Author(s) -
CzakóVér Klára,
Batiè Martin,
Raspor Peter,
Sipiczki Mathias,
Pesti Miklós
Publication year - 1999
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1999.tb13765.x
Subject(s) - schizosaccharomyces pombe , hexavalent chromium , mutant , schizosaccharomyces , chemistry , chromium , biology , microbiology and biotechnology , genetics , gene , organic chemistry
Lysine and leucine auxotrophic, heterothallic (h + , h − ) strains of Schizosaccharomyces pombe were used to obtain chromium(VI)‐sensitive and ‐tolerant mutants by ultraviolet radiation‐induced and nitrosoguanidine‐induced mutagenesis. The minimal inhibitory concentrations of K 2 Cr 2 O 7 on YEA media were 225 μM for the wild‐type strain CW‐6, 125 μM for the sensitive mutant CS‐6.51 and 275 μM for the tolerant mutant CT‐6.66. The mutants exhibited cross‐sensitivity of various patterns to Cd 2+ , Cu 2+ , Ni 2+ , Zn 2+ and VO 4 3− . Cr(VI) was added to the actively growing cultures and the total chromium (TOCr) content of the cells was determined. The sensitive mutant exhibited a high bioaccumulation ability, with a dry biomass of 810 μg g −1 after 30 min, while the tolerant mutant had a significantly lower ability than the wild‐type strain. In PIPES buffer, washed, lysine‐starved biomasses were treated with 75 μM Cr(VI) and after 2 h, the TOCr and the organically bound chromium (OBCr) were determined. Under these conditions, the sensitive and tolerant mutants had the same TOCr content, 50% of which was OBCr. The wild‐type strain exhibited a lower TOCr content than that of its mutants and only 35% of this was OBCr. The Cr(VI)‐sensitivity was due to a significantly increased uptake of Cr(VI).