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.
Prolonged maltose-limited cultivation of Saccharomyces cerevisiae selects for cells with improved maltose affinity and hypersensitivity.
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View SamplesCue-directed axon guidance depends partly on local translation in growth cones. Many mRNA transcripts are known to reside in developing axons yet little is known about their subcellular distribution or, specifically, which transcripts are in growth cones.
Subcellular profiling reveals distinct and developmentally regulated repertoire of growth cone mRNAs.
Specimen part
View SamplesThis trial was undertaken to examine the perhipheral cellular and antibody response of cattle following infestation with the cattle tick, Rhipicephalus microplus. The information from the Affymetrix gene expression data is used to complement other measurements of immune function such as cellular subset composition and antibody response in cattle of high (Brahman) and low (Holstein-Friesian) resistance to the cattle tick.
Immunological profiles of Bos taurus and Bos indicus cattle infested with the cattle tick, Rhipicephalus (Boophilus) microplus.
Sex
View SamplesAerobic, glucose-limited chemostat cultures of Saccharomyces cerevisiae grown with six different nitrogen sources were subjected to transcriptome analysis. The use of chemostats enabled an analysis of nitrogen-source-dependent transcriptional regulation at a fixed specific growth rate. A selection of preferred (ammonium and asparagine) and non-preferred (leucine, phenylalanine, methionine and proline) nitrogen sources was investigated. For each nitrogen source, distinct sets of genes were induced or repressed relative to the other five nitrogen sources. A total number of 131 of such signature transcripts were identified in this study. In addition to signature transcripts, genes were identified that showed a transcriptional co-response to two or more of the six nitrogen sources. For example, 33 genes were transcriptionally up-regulated in leucine-, phenylalanine- and methionine-grown cultures, which was partly attributed to the involvement of common enzymes in the dissimilation of these amino acids. In addition to specific transcriptional responses elicited by individual nitrogen sources, their impact on global regulatory mechanisms such as nitrogen catabolite repression (NCR) could be monitored. NCR-sensitive gene expression in the chemostat cultures showed that, ammonia and asparagine were rich nitrogen sources. By this criterion, leucine, proline and methionine were poor nitrogen sources and phenylalanine showed an intermediate NCR response.
Transcriptional responses of Saccharomyces cerevisiae to preferred and nonpreferred nitrogen sources in glucose-limited chemostat cultures.
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View SamplesPurpose: To study the mechanisms involved in the regulation by NFIX on neural stem cell development and to examine the transcriptome changes associated with the loss of NFIX in neural stem cells. Methods: Subventricular zones of 10-day-old wild-type and Nfix KO mice were sectioned and dissociated into single cells. Cells were cultured in proliferation condition for 10 days. RNA was purified and poly-A selected to build the library for RNA-seq. Conclusions: Our study represents the first detailed analysis of transcriptome changes in primary monolayer-cultured neural stem cells associated with the loss of NFIX. Overall design: Cells dissociated from 10-day-old wild-type and nuclear factor I-X (Nfix KO) mice subventricular zone were cultured in DMEM/F12 with B27, Glutamine, EGF and bFGF for 10 days. RNA was harvested with Norgen RNA purification micro kit and then prepared with illumina TruSeq kit. Samples from 6 mice (3 vs. 3) were loaded on one lane. 50-cycle single-read run was performed on Hiseq 2000. The sequence reads were analyzed by TopHat 2.0.7 followed by Cufflinks 1.3.0 with the mm9 UCSC annotation files.
Loss of NFIX Transcription Factor Biases Postnatal Neural Stem/Progenitor Cells Toward Oligodendrogenesis.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Systems biology of interstitial lung diseases: integration of mRNA and microRNA expression changes.
Specimen part, Disease
View SamplesThe mechanisms and molecular pathways underlying interstitial lung diseases (ILDs) are poorly understood. Systems biology approaches were used to identify perturbed networks in these disease states to gain a better understanding of the underlying mechanisms of disease. Through profiling genes and miRNAs, we found subsets of genes and miRNAs that distinguish different disease stages, ILDs from controls, and idiopathic pulmonary fibrosis (IPF) from non-specific interstitial pneumonitis (NSIP). Traditional pathway analysis revealed several disease-associated modules involving genes from the TGF-beta, Wnt, focal adhesion and smooth muscle actin pathways that may be involved in advancing fibrosis.
Systems biology of interstitial lung diseases: integration of mRNA and microRNA expression changes.
Specimen part, Disease
View SamplesMicrovesicles (MV) are small membrane-bound particles comprised of exosomes and various sized extracellular vesicles. These are released by a number of cell types. Microvesicles have a variety of cellular functions from communication to mediating growth and differentiation. Microvesicles contain proteins and nucleic acids. Previously, we showed that plasma microvesicles contain microRNAs (miRNAs). Based on our previous report, the majority of peripheral blood microvesicles are derived from platelets while mononuclear phagocytes, including macrophages, are the second most abundant population. Here, we characterized macrophage-derived microvesicles and whether they influenced the differentiation of nave monocytes. We also identified the miRNA content of the macrophage-derived microvesicles. We found that RNA molecules contained in the macrophage-derived microvesicles were transported to target cells, including monocytes, endothelial cells, epithelial cells and fibroblasts. Furthermore, we found that miR-223 was transported to target cells and was functionally active. Based on our observations, we hypothesize that microvesicles bind to and activate target cells. Furthermore, we find that microvesicles induce the differentiation of macrophages. Thus, defining key components of this response may identify novel targets to regulate host defense and inflammation.
Macrophage microvesicles induce macrophage differentiation and miR-223 transfer.
Specimen part, Treatment
View SamplesIn MTN-007, a phase 1, randomized, double-blinded rectal microbicide trial, we used systems genomics/proteomics to determine the effect of tenofovir 1% gel, nonoxynol-9 2% gel, placebo gel or no treatment on rectal biopsies taken at baseline, after one application or after seven daily applications (15 subjects/arm). Experiments were repeated using primary vaginal epithelial cells from four healthy women.
Mucosal effects of tenofovir 1% gel.
Specimen part, Treatment
View SamplesNo description.
Genomic and transcriptomic comparison of post-radiation versus sporadic sarcomas.
No sample metadata fields
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