Transcriptome profiling of Shewanella oneidensis gene expression following exposure to acidic and alkaline pH.
The molecular response of Shewanella oneidensis MR-1 to variations in extracellular pH was investigated based on genomewide gene expression profiling. Microarray analysis revealed that cells elicited both general and specific transcriptome responses when challenged with environmental acid (pH 4) or base (pH 10) conditions over a 60-min period. Global responses included the differential expression of genes functionally linked to amino acid metabolism, transcriptional regulation and signal transduction, transport, cell membrane structure, and oxidative stress protection. Response to acid stress included the elevated expression of genes encoding glycogen biosynthetic enzymes, phosphate transporters, and the RNA polymerase sigma-38 factor (rpoS), whereas the molecular response to alkaline pH was characterized by upregulation of nhaA and nhaR, which are predicted to encode an Na+/H+ antiporter and transcriptional activator, respectively, as well as sulfate transport and sulfur metabolism genes. Collectively, these results suggest that S. oneidensis modulates multiple transporters, cell envelope components, and pathways of amino acid consumption and central intermediary metabolism as part of its transcriptome response to changing external pH conditions.
Leaphart
Adam B
AB
Environmental Sciences Division, Oak Ridge National Laboratory, Tennessee 37831, USA.
Thompson
Dorothea K
DK
Huang
Katherine
K
Alm
Eric
E
Wan
Xiu-Feng
XF
Arkin
Adam
A
Brown
Steven D
SD
Wu
Liyou
L
Yan
Tingfen
T
Liu
Xueduan
X
Wickham
Gene S
GS
Zhou
Jizhong
J
D000143:Acids; D000468:Alkalies; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics*; D046228:Microarray Analysis; D020592:Shewanella / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D014158:Transcription, Genetic
D000143:Acids; D000468:Alkalies; D001426:Bacterial Proteins