Global analysis of brassinosteroid (BR)-mediated gene expression under abiotic stress identifies BR associated mechanisms of stress tolerance, and new stress-related genes
Gene expression and functional analyses in brassinosteroid-mediated stress tolerance.
Age, Specimen part
View SamplesThe foodborne pathogen Escherichia coli O157:H7 is commonly exposed to organic acid in processed and preserved foods, allowing adaptation and the development of tolerance to pH levels otherwise lethal. Since little is known about the molecular basis of adaptation of E. coli to organic acids, we studied K-12 MG1655 and O157:H7 Sakai during exposure to acetic-, lactic-, and hydrochloric acid at pH 5.5. The conditions required to maximimally induce the ATR of the pathotypes to all acidulants was experimentally determined. This involved incubation at pH 5.5 for 3 h (K-12) and for 2 h (O157:H7), and generated acid adapted cultures more resistant to acid challenge at pH 3.5 than bacteria that had been grown at neutral pH prior to acid-shock. To determine the transcriptomic response of K-12 and O157:H7 to each of the three acids, RNA was extracted from samples of cultures at the time of incubation corresponding to maximal induction of the ATR and from the corresponding overnight culture to serve as a control. The Affy package of the Bioconductor software was used to process raw CEL files using the robust multiarray average algorithm (RMA) for normalization, background correction, and expression value calculation. Expression levels obtained from four independent biological replicates of every condition were compared using the Limma package of the Bioconductor software. Elements with expression levels ? twofold higher or lower than the reference at a statistical significance (P-value adjustment with Benjamini and Hochberg with an adjusted P value ? 0.01, Average Expression (A value) ? 2, Log-odds (B value) ? 0) were selected. This is the first transcriptomic study to demonstrate and characterise the stationary phase acidulant and pathotype specific ATR of E. coli. A core set of genes were also found to be universally expressed by both pathotypes regardless of acidulant type.
Transcriptomic analysis of the acid tolerance responses of Escherichia coli O157:H7 and K-12 to inorganic and organic acids reveals an acidulant and pathotype-specific response
Subject, Compound, Time
View SamplesIn a previous study we adopted an integrated transcriptomic and proteomic approach to determine the physiological response of E. coli O157:H7 Sakai during exponential phase growth under steady-state conditions relevant to low temperature and water activity conditions experienced during meat carcass chilling in cold air (Kocharunchitt et al., 2012). The findings of that study provide a baseline of knowledge of the physiology of this pathogen, with the response of E. coli O157:H7 to steady-state conditions of combined cold and osmotic stress. To provide an insight into the genetic systems enabling this organism to adapt to growth at low temperature, we extended the aforementioned study to investigate the growth kinetics of E. coli O157:H7 Sakai during abrupt temperature downshift from 35 degrees C to 14 degrees C and, examined time-dependent global alterations in its genome expression upon cold shock from 35 degrees C to 14 degrees C. The genome-wide expression response of E. coli was analysed by both cDNA microarray (transcriptome response) and 2D-LC/MS/MS analysis (proteome response). Differences in gene and protein expression patterns in E. coli before and after cold shock were analysed through quantitative and comparative analysis of time series changes in both mRNA and proteins levels.
Global genome response of Escherichia coli O157:H7 Sakai during dynamic changes in growth kinetics induced by an abrupt temperature downshift
Time
View SamplesAn integrated genomic and proteomic analysis was undertaken to determine the physiological response of Escherichia coli O157:H7 Sakai to steady-state conditions relevant to low temperature and water activity conditions experienced during meat carcase chilling in cold air. The response of E. coli during exponential growth at 25°C aw 0.985, 14°C aw 0.985, 25°C aw 0.967 and, 14°C aw 0.967 was compared to that of a reference culture (35°C aw 0.993).
Integrated transcriptomic and proteomic analysis of the physiological response of Escherichia coli O157:H7 Sakai to steady-state conditions of cold and water activity stress
Subject
View SamplesTo gain a deep understanding of mRNA turnover dynamics in mammalian cells, we pulse labeled newly synthesized RNA in 3t3 cells for 2 h with 4sU. RNA samples were fractionated into the newly synthesized and pre-existing fractions. Both fractions and the total RNA sample were analyzed by mRNA sequencing. We estimated mRNA half-lives based on the ratios of newly synthesized RNA/total RNA ratio and the preexisting RNA/total RNA.
Global quantification of mammalian gene expression control.
No sample metadata fields
View SamplesThe Arabidopsis thaliana NAC domain transcription factor, VASCULAR-RELATED NAC-DOMAIN7 (VND7), acts as a key regulator of xylem vessel differentiation. In order to identify direct target genes of VND7, we performed global transcriptome analysis using Arabidopsis transgenic lines in which VND7 activity could be induced post-translationally. This analysis identified 63 putative direct target genes of VND7, which encode a broad range of proteins, such as transcription factors, IRREGULAR XYLEM proteins and proteolytic enzymes, known to be closely associated with xylem vessel formation. Recombinant VND7 protein binds to several promoter sequences present in candidate direct target genes: specifically, in the promoter of XYLEM CYSTEINE PEPTIDASE1, two distinct regions were demonstrated to be responsible for VND7 binding. We also found that expression of VND7 restores secondary cell wall formation in the fiber cells of inflorescence stems of nst1nst3 double mutants, as well as expression of NAC SECONDARY WALL THICKENING PROMOTING FACTOR3 (NST3, however, the vessel-type secondary wall deposition was observed only as a result of VND7 expression. These findings indicated that VND7 upregulates, directly and/or indirectly, many genes involved in a wide range of processes in xylem vessel differentiation, and that its target genes are partially different from those of NSTs.
VASCULAR-RELATED NAC-DOMAIN7 directly regulates the expression of a broad range of genes for xylem vessel formation.
Age, Specimen part, Treatment
View SamplesThe expression of four transcription factors (OCT3/4, SOX2, KLF4, and c-MYC) can reprogram mouse as well as human somatic cells to induced pluripotent stem (iPS) cells. Expression of the c-MYC, also known as an oncogene, might induce carcinogenesis and thus, iPS cells produced with the use of c-MYC transduction cannot be used for human therapeutic applications. Furthermore, reprogramming efficiency was significantly reduced in the absence of c-MYC transduction. Here, we generated iPS cells from mesenchymal stromal cells (MSCs) derived from human third molars (wisdom teeth) by retroviral transduction of OCT3/4, SOX2, and KLF4 without c-MYC. Interestingly, clonally expanded MSCs, named 10F-15, could be used for iPS cell generation with 100-fold higher efficiency compared to that of other clonally expanded MSCs and human dermal fibroblasts. These iPS cells resembled human embryonic stem (ES) cells in many aspects, including morphology, ES markers expression, global gene expression, epigenetic states, and the ability to differentiate into the three germ layers in vitro and in vivo. Because human third molars are discarded as clinical waste, our data indicate that MSCs isolated from human third molars are a valuable cell source for the generation of iPS cells.
Induction of pluripotent stem cells from human third molar mesenchymal stromal cells.
Specimen part, Cell line
View SamplesR1R2R3-Myb proteins represent an evolutionarily conserved class of Myb family proteins important for cell cycle regulation and differentiation in eukaryotic cells. In plants, this class of Myb proteins are believed to play important roles in cell cycle regulation through transcriptional regulation of G2/M phase-specific genes by binding to common cis-elements, called MSA elements. In Arabidopsis thaliana, MYB3R1 and MYB3R4 act as transcriptional activators and positively regulate cytokinesis by activating transcription of KNOLLE, which encodes a cytokinesis-specific syntaxin. Here, we show that the double mutation myb3r1 myb3r4 causes pleiotropic developmental defects, some of which are due to deficiency of KNOLLE whereas other are not, suggesting multiple target genes are involved. Consistently, microarray analysis of the double mutant revealed altered expression of many genes, among which G2/M-specific genes showed significant overrepresentation of the MSA motif and a strong tendency to be down-regulated by the double mutation. Our results demonstrate, on a genome-wide level, the importance of the MYB3R-MSA pathway for regulating G2/M-specific transcription. In addition, MYB3R1 and MYB3R4 may have diverse roles during plant development by regulating G2/M-specific genes with various functions, as well as genes possibly unrelated to the cell cycle.
Mutations in MYB3R1 and MYB3R4 cause pleiotropic developmental defects and preferential down-regulation of multiple G2/M-specific genes in Arabidopsis.
Age, Specimen part
View SamplesGenome-wide expression analysis of two circadian oscillatory mechanisms in the mouse liver
Genome-wide expression analysis reveals 100 adrenal gland-dependent circadian genes in the mouse liver.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Time-Course Analysis of Brain Regional Expression Network Responses to Chronic Intermittent Ethanol and Withdrawal: Implications for Mechanisms Underlying Excessive Ethanol Consumption.
Sex, Specimen part
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