Whole-Genome Transcriptional Analysis of Chemolithoautotrophic Thiosulfate Oxidation by Thiobacillus denitrificans Under Aerobic vs. Denitrifying Conditions

Journal Article · Sat Apr 22 04:00:00 EDT 2006 · Journal of Bacteriology, vol. 188, no. 19, October 1, 2006, pp. 7005-7015

OSTI ID:897966

Beller, H R; Letain, T E; Chakicherla, A; Kane, S R; Legler, T C; Coleman, M A

Thiobacillus denitrificans is one of the few known obligate chemolithoautotrophic bacteria capable of energetically coupling thiosulfate oxidation to denitrification as well as aerobic respiration. As very little is known about the differential expression of genes associated with ke chemolithoautotrophic functions (such as sulfur-compound oxidation and CO2 fixation) under aerobic versus denitrifying conditions, we conducted whole-genome, cDNA microarray studies to explore this topic systematically. The microarrays identified 277 genes (approximately ten percent of the genome) as differentially expressed using Robust Multi-array Average statistical analysis and a 2-fold cutoff. Genes upregulated (ca. 6- to 150-fold) under aerobic conditions included a cluster of genes associated with iron acquisition (e.g., siderophore-related genes), a cluster of cytochrome cbb3 oxidase genes, cbbL and cbbS (encoding the large and small subunits of form I ribulose 1,5-bisphosphate carboxylase/oxygenase, or RubisCO), and multiple molecular chaperone genes. Genes upregulated (ca. 4- to 95-fold) under denitrifying conditions included nar, nir, and nor genes (associated respectively with nitrate reductase, nitrite reductase, and nitric oxide reductase, which catalyze successive steps of denitrification), cbbM (encoding form II RubisCO), and genes involved with sulfur-compound oxidation (including two physically separated but highly similar copies of sulfide:quinone oxidoreductase and of dsrC, associated with dissimilatory sulfite reductase). Among genes associated with denitrification, relative expression levels (i.e., degree of upregulation with nitrate) tended to decrease in the order nar > nir > nor > nos. Reverse transcription, quantitative PCR analysis was used to validate these trends.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 897966
• Report Number(s): UCRL-JRNL-220798
• Journal Information: Journal of Bacteriology, vol. 188, no. 19, October 1, 2006, pp. 7005-7015, Journal Name: Journal of Bacteriology, vol. 188, no. 19, October 1, 2006, pp. 7005-7015
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
59 BASIC BIOLOGICAL SCIENCES
AEROBIC CONDITIONS
BACTERIA
CYTOCHROMES
DENITRIFICATION
GENES
IRON
NITRATES
NITRIC OXIDE
NITRITES
OXIDASES
OXIDATION
OXIDOREDUCTASES
RESPIRATION
RIBULOSE
SULFITES
THIOSULFATES
TRANSCRIPTION