PMID:16621832

Citation	Ackerley, DF , Barak, Y , Lynch, SV , Curtin, J and Matin, A (2006) Effect of chromate stress on Escherichia coli K-12. J. Bacteriol. 188:3371-81
Abstract	The nature of the stress experienced by Escherichia coli K-12 exposed to chromate, and mechanisms that may enable cells to withstand this stress, were examined. Cells that had been preadapted by overnight growth in the presence of chromate were less stressed than nonadapted controls. Within 3 h of chromate exposure, the latter ceased growth and exhibited extreme filamentous morphology; by 5 h there was partial recovery with restoration of relatively normal cell morphology. In contrast, preadapted cells were less drastically affected in their morphology and growth. Cellular oxidative stress, as monitored by use of an H2O2-responsive fluorescent dye, was most severe in the nonadapted cells at 3 h postinoculation, lower in the partially recovered cells at 5 h postinoculation, and lower still in the preadapted cells. Chromate exposure depleted cellular levels of reduced glutathione and other free thiols to a greater extent in nonadapted than preadapted cells. In both cell types, the SOS response was activated, and levels of proteins such as SodB and CysK, which can counter oxidative stress, were increased. Some mutants missing antioxidant proteins (SodB, CysK, YieF, or KatE) were more sensitive to chromate. Thus, oxidative stress plays a major role in chromate toxicity in vivo, and cellular defense against this toxicity involves activation of antioxidant mechanisms. As bacterial chromate bioremediation is limited by the toxicity of chromate, minimizing oxidative stress during bacterial chromate reduction and bolstering the capacity of these organisms to deal with this stress will improve their effectiveness in chromate bioremediation.
Links	PubMed PMC1447458 Online version:10.1128/JB.188.9.3371-3381.2006
Keywords	Adaptation, Physiological; Chromates; Culture Media; Escherichia coli K12/cytology; Escherichia coli K12/growth & development; Escherichia coli K12/physiology; Escherichia coli Proteins/metabolism; Oxidative Stress; beta-Galactosidase/metabolism
edit table

Main Points of the Paper

Please summarize the main points of the paper.

Materials and Methods Used

Please list the materials and methods used in this paper (strains, plasmids, antibodies, etc).

Phenotype Annotations

See Help:AnnotationTable for details on how to edit this table.

Phenotype of	Taxon Information	Genotype Information (if known)	Condition Information	OMP ID	OMP Term Name	ECO ID	ECO Term Name	Notes	Status
cysK	Taxon: Escherichia coli Strain: K-12 Substrain: BW25113 NCBI Taxon ID: 679895	Genotype of Reference Strain:	Reference Condition:					WT Chromate MIC50 (?M) 400
cysN	Taxon: Escherichia coli Strain: K-12 Substrain: BW25113 NCBI Taxon ID: 679895	Genotype of Reference Strain:	Reference Condition:					WT Chromate MIC50 (?M) 400
katE	Taxon: Escherichia coli Strain: K-12 Substrain: BW25113 NCBI Taxon ID: 679895	Genotype of Reference Strain:	Reference Condition:
katG	Taxon: Escherichia coli Strain: K-12 Substrain: BW25113 NCBI Taxon ID: 679895	Genotype of Reference Strain:	Reference Condition:
gshA	Taxon: Escherichia coli Strain: K-12 Substrain: BW25113 NCBI Taxon ID: 679895	Genotype of Reference Strain:	Reference Condition:
gshB	Taxon: Escherichia coli Strain: K-12 Substrain: BW25113 NCBI Taxon ID: 679895	Genotype of Reference Strain:	Reference Condition:
sodA	Taxon: Escherichia coli Strain: K-12 Substrain: BW25113 NCBI Taxon ID: 679895	Genotype of Reference Strain:	Reference Condition:
sodB	Taxon: Escherichia coli Strain: K-12 Substrain: BW25113 NCBI Taxon ID: 679895	Genotype of Reference Strain:	Reference Condition:
yieF	Taxon: Escherichia coli Strain: K-12 Substrain: BW25113 NCBI Taxon ID: 679895	Genotype of Reference Strain:	Reference Condition:
fliC	Taxon: Escherichia coli Strain: K-12 Substrain: BW25113 NCBI Taxon ID: 679895	Genotype of Reference Strain:	Reference Condition:
ompW	Taxon: Escherichia coli Strain: K-12 Substrain: BW25113 NCBI Taxon ID: 679895	Genotype of Reference Strain:	Reference Condition:
ftnA	Taxon: Escherichia coli Strain: K-12 Substrain: BW25113 NCBI Taxon ID: 679895	Genotype of Reference Strain:	Reference Condition:
sspA	Taxon: Escherichia coli Strain: K-12 Substrain: BW25113 NCBI Taxon ID: 679895	Genotype of Reference Strain:	Reference Condition:
cysK	Taxon: Escherichia coli Strain: K-12 Substrain: BW25113 NCBI Taxon ID: 679895	Genotype of Reference Strain:	Reference Condition:					WT Chromate MIC50 (?M) 400
edit table

References

See Help:References for how to manage references in OMPwiki.