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GSE47406
Staphylococcus aureus
18 Downloadable Samples
Affymetrix S. aureus Genome Array (saureus)
Description
Staphylococcus aureus thymidine-dependent small-colony variants (TD-SCVs) are frequently isolated from patients with chronic S. aureus infections after long-term treatment with trimethoprim-sulfamethoxazole (TMP-SMX). In TD-SCVs, mutations of thymidylate synthase (thyA, TS), essential for DNA synthesis, occur. However, it has never been shown, that TMP-SMX is responsible for the induction and selection of TD-SCVs. Short-term exposure of TMP-SMX induced the TD-SCV phenotype morphologically as shown in transmission electron-microscopy and on the transcriptional level by qRT-PCR in wild-type S. aureus, while selection of TD-SCVs with thyA mutations occurred only rarely after long-term exposure. In reversion experiments with clinical TD-SCVs, all revertants revealed compensating mutations at the initially identified mutation site. Whole DNA microarray analysis of a thyA deletion mutant (thyA), which exhibited the typical TD-SCV phenotype, identified tremendous alterations compared to the wild-type. Important virulence regulators such as agr, arlRS, sarA and major virulence determinants including hla, hlb, sspA, sspB and geh were down-regulated, while genes associated with the colonization capacity like fnbA, fnbB, spa, clfB, sdrC and sdrD were up-regulated. The expression of genes involved in pyrimidine and purine metabolism as well as in nucleotide interconversion changed significantly. The thyA-mutant was attenuated in virulence in both, a Caenorhabditis elegans killing model and an acute murine pneumonia model. Furthermore, competition experiments in vitro and in vivo (using a chronic pneumonia mouse model) revealed a survival and growth advantage of the thyA-mutant under low thymidine conditions and TMP-SMX exposure. In conclusion, our results clearly show for the first time that TMP-SMX induces the TD-SCV phenotype after short-term exposure in S. aureus and that long-term exposure selects thyA mutations providing an advantage for TD-SCVs under specified conditions. Thus, our results help to understand the dynamic processes of induction and selection of S. aureus TD-SCVs during TMP-SMX exposure.
Publication Title
Inactivation of thyA in Staphylococcus aureus attenuates virulence and has a strong impact on metabolism and virulence gene expression.
Sample Metadata Fields
Time
View Samples- Mus musculus
- 36 Downloadable Samples
- Affymetrix Mouse Expression 430A Array (moe430a)
Description
In order to test the hypothesis that fibroblasts from different tissues are phenotypically distinct from one another, we have subjected tendon, skin and corneal fibroblasts of fetal mouse to mechanical stimulation by fluid flow and analyzed the transcriptional responses of the cells using Affymetrix MOE430 chip set containing two arrays MOE430A and MOE430B.
Publication Title
Phenotypic responses to mechanical stress in fibroblasts from tendon, cornea and skin.
Sample Metadata Fields
No sample metadata fields
View Samples- Saccharomyces cerevisiae
- 17 Downloadable Samples
- Affymetrix Yeast Genome S98 Array (ygs98)
Description
Physiological effects of carbon dioxide and impact on genome-wide transcript profiles were analysed in chemostat cultures of Saccharomyces cerevisiae. In anaerobic, glucose-limited chemostat cultures grown at atmospheric pressure, cultivation under CO2-saturated conditions had only a marginal (<10%) impact on the biomass yield. Conversely, a 25% decrease of the biomass yield was found in aerobic, glucose-limited chemostat cultures aerated with a mixture of 79% CO2 and 21% O2. This observation indicated that respiratory metabolism is more sensitive to CO2 than fermentative metabolism. Consistent with the more pronounced physiological effects of CO2 in respiratory cultures, the number of CO2-responsive transcripts was higher in aerobic cultures than in anaerobic cultures. Many genes involved in mitochondrial functions showed a transcriptional response to elevated CO2 concentrations. This is consistent with an uncoupling effect of CO2 and/or intracellular bicarbonate on the mitochondrial inner membrane. Other transcripts that showed a significant transcriptional response to elevated CO2 included NCE103 (probably encoding carbonic anhydrase), PCK1 (encoding PEP carboxykinase) and members of the IMD gene family (encoding isozymes of inosine monophosphate dehydrogenase
Publication Title
Physiological and genome-wide transcriptional responses of Saccharomyces cerevisiae to high carbon dioxide concentrations.
Sample Metadata Fields
No sample metadata fields
View Samples- Saccharomyces cerevisiae
- 3 Downloadable Samples
- Affymetrix Yeast Genome S98 Array (ygs98)
Description
Prolonged cultivation (>25 generations) of Saccharomyces cerevisiae in aerobic, maltose-limited chemostat cultures led to profound physiological changes. Maltose hypersensitivity was observed when cells from prolonged cultivations were suddenly exposed to excess maltose. This substrate hypersensitivity was evident from massive cell lysis and loss of viability. During prolonged cultivation at a fixed specific growth rate, the affinity for the growth-limiting nutrient (i.e., maltose) increased, as evident from a decreasing residual maltose concentration. Furthermore, the capacity of maltose-dependent proton uptake increased up to 2.5-fold during prolonged cultivation. Genome-wide transcriptome analysis showed that the increased maltose transport capacity was not primarily due to increased transcript levels of maltose-permease genes upon prolonged cultivation. We propose that selection for improved substrate affinity (ratio of maximum substrate consumption rate and substrate saturation constant) in maltose-limited cultures leads to selection for cells with an increased capacity for maltose uptake. At the same time, the accumulative nature of maltose-proton symport in S. cerevisiae leads to unrestricted uptake when maltose-adapted cells are exposed to a substrate excess. These changes were retained after isolation of individual cell lines from the chemostat cultures and nonselective cultivation, indicating that mutations were involved. The observed trade-off between substrate affinity and substrate tolerance may be relevant for metabolic engineering and strain selection for utilization of substrates that are taken up by proton symport.
Publication Title
Prolonged maltose-limited cultivation of Saccharomyces cerevisiae selects for cells with improved maltose affinity and hypersensitivity.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 12 Downloadable Samples
- Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
Maggot ES is known to induce wound healing in vivo to improve chronic wound repair. The effects have been studies at the protein and molecular level but never before at the transcriptional level.
Publication Title
The transcriptional responses of cultured wound cells to the excretions and secretions of medicinal Lucilia sericata larvae.
Sample Metadata Fields
Specimen part, Cell line
View Samples- Saccharomyces cerevisiae
- 8 Downloadable Samples
- Affymetrix Yeast Genome S98 Array (ygs98)
Description
The capacity of respiring cultures of Saccharomyces cerevisiae to instantaneously switch to fast alcoholic fermentation upon a transfer to anaerobic sugar-excess conditions is a key characteristic of Saccharomyces cerevisiae in many of its industrial applications. This transition was studied by exposing aerobic glucose-limited chemostat cultures grown at a low specific growth rate to two simultaneous perturbations: oxygen depletion and relief of glucose limitation. This shift towards fully fermentative conditions caused a massive transcriptional response, where one third of all genes within the genome were transcribed differentially. During the first 30 min, most of these changes were driven by relief from glucose limitation. An anaerobic induction response was only observed after the initial response to glucose excess. By comparing this study with public datasets representing dynamic and steady conditions, 14 up-regulated and 11 down-regulated genes were determined to be anaerobiosis specific and can therefore be use as signature transcripts for anaerobicity under dynamic as well as under steady state conditions
Publication Title
New insights into the Saccharomyces cerevisiae fermentation switch: dynamic transcriptional response to anaerobicity and glucose-excess.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 9 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
To identify distinct transcriptional patterns between the major subcortical dopamine targets commonly studied in addiction we studied differences in gene expression between the bed nucleus of the stria terminalis (BNST), nucleus accumbens (NAc), and dorsal striatum (dStr) using microarray analysis. We first tested for differences in expression of genes encoding transcripts for common neurotransmitter systems as well as calcium binding proteins routinely used in neuroanatomical delineation of brain regions. This a priori method revealed differential expression of corticotropin releasing hormone (Crh), the GABA transporter (Slc6a1), and prodynorphin (Pdyn) mRNAs as well as several others. Using a gene ontology tool, functional scoring analysis, and Ingenuity Pathway Analysis, we further identified several physiological pathways that were distinct among these brain regions. These two different analyses both identified calcium signaling, G15 coupled protein receptor signaling, and adenylate cyclase-related signaling as significantly different among the BNST, NAc, and dStr. These types of signaling pathways play important roles in, amongst other things, synaptic plasticity. Investigation of differential gene expression revealed several instances that may provide insight into reported differences in synaptic plasticity between these brain regions. The results support other studies suggesting that crucial pathways involved in neurotransmission are distinct among the BNST, NAc, and dStr, and provide insight into the potential use of pharmacological agents that may target region-specific signaling pathways. Further, these studies provide a framework for future mouse-mouse comparisons of transcriptional profiles after behavioral/pharmacological manipulation.
Publication Title
Microarray analysis reveals distinctive signaling between the bed nucleus of the stria terminalis, nucleus accumbens, and dorsal striatum.
Sample Metadata Fields
No sample metadata fields
View Samples- Saccharomyces cerevisiae
- 29 Downloadable Samples
- Affymetrix Yeast Genome S98 Array (ygs98)
Description
Addition of 3 new arrays made from carbon limited chemostat of CENPK113-7D and 3 new arrays made from aerobic carbon limited chemostat of CENPK113-7D Complmentary data to the data of the serie GSE1723.
Publication Title
Exploiting combinatorial cultivation conditions to infer transcriptional regulation.
Sample Metadata Fields
No sample metadata fields
View Samples- Saccharomyces cerevisiae
- 23 Downloadable Samples
- Affymetrix Yeast Genome S98 Array (ygs98)
Description
The goal of this study was to study this interaction by analyzing genome-wide transcriptional responses to four different nutrient-limitation regimes under aerobic and anaerobic conditions in chemostat cultures of S. cerevisiae. This two-dimensional approach resulted in a new, robust set of anaerobic and aerobic signature transcripts for S. cerevisiae, as well as to a refinement of previous reports on nutrient-responsive genes. Moreover, the identification of genes regulated both by nutrient and oxygen availability provided new insight in cross-regulated network and hierarchy in the control of gene expression.
Publication Title
Two-dimensional transcriptome analysis in chemostat cultures. Combinatorial effects of oxygen availability and macronutrient limitation in Saccharomyces cerevisiae.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens, Saccharomyces cerevisiae
- 2 Downloadable Samples
- Illumina HumanHT-12 V4.0 expression beadchip
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
The deafness gene DFNA5 induces programmed cell death through mitochondria and MAPK-related pathways.
Sample Metadata Fields
Specimen part, Cell line
View Samples