Global responses of Escherichia coli to adverse conditions determined by microarrays and FT-IR spectroscopy.
The global gene expression and biomolecular composition in an Escherichia coli model strain exposed to 10 adverse conditions (sodium chloride, ethanol, glycerol, hydrochloric and acetic acid, sodium hydroxide, heat (46 degrees C), and cold (15 degrees C), as well as ethidium bromide and the disinfectant benzalkonium chloride) were determined using DNA microarrays and Fourier transform infrared (FT-IR) spectroscopy. In total, approximately 40% of all investigated genes (1682/4279 genes) significantly changed expression, compared with a nonstressed control. There were, however, only 3 genes (ygaW (unknown function), rmf (encoding a ribosomal modification factor), and ghrA (encoding a glyoxylate/hydroxypyruvate reductase)) that significantly changed expression under all conditions (not including benzalkonium chloride). The FT-IR analysis showed an increase in unsaturated fatty acids during ethanol and cold exposure, and a decrease during acid and heat exposure. Cold conditions induced changes in the carbohydrate composition of the cell, possibly related to the upregulation of outer membrane genes (glgAP and rcsA). Although some covariance was observed between the 2 data sets, principle component analysis and regression analyses revealed that the gene expression and the biomolecular responses are not well correlated in stressed populations of E. coli, underlining the importance of multiple strategies to begin to understand the effect on the whole cell.
Moen
Birgitte
B
Nofima Mat, N-1430 As, Norway. birgitte.moen@nofima.no
Janbu
Astrid Oust
AO
Langsrud
Solveig
S
Langsrud
Oyvind
O
Hobman
Jon L
JL
Constantinidou
Chrystala
C
Kohler
Achim
A
Rudi
Knut
K
D001426:Bacterial Proteins / Q000235:genetics; D004926:Escherichia coli / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D020411:Oligonucleotide Array Sequence Analysis; D009930:Organic Chemicals / Q000494:pharmacology; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
D001426:Bacterial Proteins; D005227:Fatty Acids; D009930:Organic Chemicals