Project description:Beller, H. R., T. E. Letain, A. Chakicherla, S. R. Kane, T. C. Legler, and M. A. Coleman. 2006. Whole-genome transcriptional analysis of chemolithoautotrophic thiosulfate oxidation by Thiobacillus denitrificans under aerobic vs. denitrifying conditions. Journal of Bacteriology 188:7005-7015. 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 key 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. Keywords: bacterial metabolism
Project description:Investigation of whole genome gene expression level changes in anaerobic, nitrate-dependent Fe(II) oxidation in the chemolithoautotrophic bacterium Thiobacillus denitrificans Here we report on a study to identify genes associated with nitrate-dependent Fe(II) oxidation by whole-genome transcriptional (microarray) assays including the use of FeCO3, Fe2+, and U(IV) oxides as electron donors under denitrifying conditions. A 25 chip study using total RNA recovered from wild-type T. denitrificans was cultivated at 30oC under strictly anaerobic conditions with growth medium that contained 20 mM thiosulfate, 20 mM nitrate, and 30 mM bicarbonate (pH ~7) and exposed to 8 treatments. Each chip measures the expression level of 2832 ORFs with N 24-mer probe pairs (PM/MM) per gene, with three-fold technical redundancy.
Project description:Investigation of whole genome gene expression level changes in anaerobic, nitrate-dependent Fe(II) oxidation in the chemolithoautotrophic bacterium Thiobacillus denitrificans
Project description:Genome-enabled studies of anaerobic, nitrate-dependent Fe(II) oxidation in the chemolithoautotrophic bacterium Thiobacillus denitrificans
Project description:Quantitative proteomic analysis of Paracoccus denitrificans PD1222 wild type and NtrY defective mutant in denitrifying conditions (anaerobiosis, nitrate as nitrogen source)
Project description:Transcriptome profiles of an aerobic photosynthetic bacterium Roseobacter denitrificans OCh114 grown under different oxygen tension and light irradiation conditions were determined by NimbleGen Prokaryotic Expression array (12x135K).
Project description:Transcriptional profiling of Paracoccus denitrificans PD1222 wild type incubated in continuous culture (continuous culture (CSTR)) in minimal media with aerobic or anaerobic conditions. The goal was to define the core respiratory genes.
Project description:We report here the RNA seq results of sRNA enriched Paracoccus denitrificans grown under three different N2O levels (high N2O reffered to as CuL/ low N2O reffered to as CuH/ Low N2O aerobic reffered to as CuH O2)
Project description:Chemoautotrophic bacteria belonging to the genus Sulfurimonas in the class Campylobacteria (formerly classified as Epsilonproteobacteria) play a key role in the sulfur cycle in a variety of oxygen-deficient or –limited and sulfide-rich marine and terrestrial environments. Previously, they were identified as key players in the turnover of zero-valence sulfur, a central intermediate in the marine sulfur cycle, and S. denitrificans was further shown to be able to oxidize cyclooctasulfur. However, at present the mechanism involved in the activation and metabolism of cyclooctasulfur is not known. To this end, we assessed the transcriptome and proteome of S. denitrificans grown with either thiosulfate or cyclooctasulfur as the electron donor. While the overall profiles under the two growth conditions were rather similar, distinct differences were observed that could be attributed to the utilization of cyclooctasulfur. This included a higher abundance of expressed genes and proteins related to attachment in the presence of cyclooctasulfur and the differential expression of the sulfur-oxidation multienzyme complex (SOX). S. denitrificans uses the SOX system for the oxidation of reduced sulfur compounds, including two copies of the sulfur-binding SoxYZ proteins, encoded in two gene clusters: soxABXYZ1 and soxCDYZ2. While the proteins of both operons of the SOX system were detected in the presence of thiosulfate, only proteins of the soxCDYZ2 operon were detected when grown with cylcooctasulfur. Based on these findings a model for the oxidation of cylcooctasulfur is being proposed that might also apply to other Campylobacteria that share the same arrangement of the SOX system. Our results have implications for interpreting metatranscriptomic and -proteomic data and for the observed high level of diversification of soxYZ2 among sulfur-oxidizing Campylobacteria.
