Laboratory strains of Saccharmoyces cerevisiae have been widely used as a model for studying eukaryotic cells and mapping the molecular mechanisms of many different human diseases. Industrial wine yeasts, on the other hand, have been selected over hundreds of years on the basis of their adaptation to stringent environmental conditions and the organoleptic properties they confer to wine. Here, we applied a two-factor design to study the response of a standard laboratory strain, CEN.PK.113-7D, and an industrial wine yeast-strain, EC1118, to growth temperature at 15C and 30C under 12 nitrogen-limited, anaerobic steady-state chemostat cultures. Physiological characterization revealed that growth temperature strongly impacted biomass yields in both strains. Moreover, we observed that the wine yeast is better adapted to mobilizing resources for biomass and that the laboratory yeast exhibited higher fermentation rates. To elucidate mechanistic differences controlling the growth temperature response and underlying adaptive mechanisms between strains, DNA microarrays and targeted metabolome analysis were used. We identified 1007 temperature dependent genes and 473 strain dependent genes. The transcriptional response was used to identify highly correlated subnetworks of significantly changing genes in metabolism. We show that temperature differences most strongly affect nitrogen metabolism and the heat shock response. Lack of STRE mediated gene induction, coupled with reduced trehalose levels, indicates a decreased general stress response at 15C relative to 30C. Between strains, differential responses are centred around sugar uptake, nitrogen metabolism and expression of genes related to organoleptic properties. Our study provides global insight into how growth temperature exerts a differential physiological and transcriptional response in laboratory and wine strains of S. cerevisiae.
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View SamplesAuxin is a key phytohormone regulating central processes in plants that include embryo development, lateral root growth and flower maturation among others. Auxin is sensed by a set of F-Box proteins of the TIR1/AFB3 family triggering auxin dependent responses by a pathway that involves an interplay between the Aux/IAA transcription repressors and the ARF transcription factors. We have previously shown that the AFB3 auxin receptor has a specific role in coordinating primary and lateral root growth to external and internal nitrate availability (Vidal et al., 2010). In this work, we used an integrated genomics, bioinformatics and molecular genetics approach to dissect regulatory networks acting downstream AFB3 that are activated by a transient nitrate treatment in Arabidopsis roots. Our systems approach unraveled key components of the AFB3 regulatory network leading to changes in lateral root growth in response to nitrate.
Systems approaches map regulatory networks downstream of the auxin receptor AFB3 in the nitrate response of Arabidopsis thaliana roots.
Specimen part, Treatment
View SamplesPlant growth promoting rhizobacteria (PGPR) induce positive effects in plants, such as increased growth or reduced stress susceptibility. The mechanisms behind PGPR/plant interaction are poorly understood, as most studies have described short- term responses on plants and only a few studies have analyzed plant molecular responses under PGPR colonization.
Effects of the plant growth-promoting bacterium Burkholderia phytofirmans PsJN throughout the life cycle of Arabidopsis thaliana.
Specimen part, Time
View SamplesBoron is an essential micronutrient for plants and is taken up in the form of boric acid (BA). Despite this, a high BA concentration is toxic for the plants, inhibiting root growth and is thus a significant problem in semi-arid areas in the world. In this work, we report the molecular basis for the inhibition of root growth caused by boron. We used microarrays to detail the global gene expression underlying boron toxicity in roots.
A molecular framework for the inhibition of Arabidopsis root growth in response to boron toxicity.
Specimen part, Treatment
View SamplesIn this experiment we used leaves from 6-week-old Arabidopsis SDH1-1/sdh1-1 mutant and Wt plants (Ws). The leaves were collected in the middle of light period.
A deficiency in the flavoprotein of Arabidopsis mitochondrial complex II results in elevated photosynthesis and better growth in nitrogen-limiting conditions.
Age, Specimen part, Time
View SamplesTrypanosoma cruzi is an obligate intracellular protozoan parasite that causes human Chagas disease, a leading cause of heart failure in Latin America. Using Affymetrix oligonucleotide arrays we screened phenotypically diverse human cells (foreskin fibroblasts, microvascular endothelial cells and vascular smooth muscle cells) for a common transcriptional response signature to T. cruzi. A common feature was a prominent type I interferon response, indicative of a secondary response to secreted cytokines. Using transwell plates to distinguish cytokine-dependent and -independent gene expression profiles in T. cruzi-infected cells, a core cytokine-independent response was identified in fibroblasts and endothelial cells that featured metabolic and signaling pathways involved in cell proliferation, amino acid catabolism and response to wounding. Significant downregulation of genes involved in mitotic cell cycle and cell division predicted that T. cruzi infection impedes cell cycle progression in the host cell.
Cytokine-dependent and-independent gene expression changes and cell cycle block revealed in Trypanosoma cruzi-infected host cells by comparative mRNA profiling.
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View SamplesThe intracellular pathogen Trypanosoma cruzi secretes an activity that blocks TGF--dependent induction of connective tissue growth factor (CTGF/CCN2). Here, we address the mechanistic basis for T. cruzi-mediated interference of
A soluble factor from Trypanosoma cruzi inhibits transforming growth factor-ß-induced MAP kinase activation and gene expression in dermal fibroblasts.
Specimen part
View SamplesThe GeneChip Porcine Genome Array was used to identify the transcriptional response upon Salmonella typhimurium infection in three porcine intestinal sections (jejumun, ileum and colon) along a time course of 1,2 and 6 days post infection.
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Specimen part, Treatment
View SamplescAMP receptor protein (CRP, also known as the catabolite activator protein [CAP]) is arguably the best-studied of the global transcription factors of E coli. CRP alone is responsible for regulating at least 283 operons. Upon binding cAMP, the CRP dimer binds DNA and directly interacts with RNA polymerase (RNAP). At Class II promoters, CRP binds near position -41,5 relative to the transcription start site and contacts the amino-terminal domain of the RNAP subunit (RNAP-NTD). This interaction requires AR2, a patch of primarily positively charged residues (H19, H21, E96, and K101) that interact with negatively charged residues on RNAP-NTD. Acetylome analyses consistently detect lysine 100 (K100) of CRP as acetylated. Since K100 is adjacent to the positively charged AR2, we hypothesized that the K100 positive charge may also play a role in CRP function. We further hypothesized that acetylation of K100 would neutralize this positive charge, leading to a potential regulatory mechanism
Influence of Glucose Availability and CRP Acetylation on the Genome-Wide Transcriptional Response of <i>Escherichia coli</i>: Assessment by an Optimized Factorial Microarray Analysis.
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View SamplesThe genomic causes of inbreeding depression are poorly known. Several studies have found widespread transcriptomic alterations in inbred organisms, but it remains unclear which of these alterations are causes of the depression and which are mere responses to the ensuing physiological stress.
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Specimen part
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