Short term perturbation
Ontology highlight
ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE3821 | GEO | 2005/12/16
SECONDARY ACCESSION(S): PRJNA94037
REPOSITORIES: GEO
Similar Datasets
Project description:Study of the short term (within the first 330 seconds) transcriptional response of S.cerevisiae upon a sudden addition of glucose. Experiment Overall Design: Chemostat cultivation â Saccharomyces cerevisiae (CEN PK 113-7D) was cultivated in an aerobic carbon-limited chemostat culture in a 7-litres fermentor (Applikon, The Netherlands) with a working volume of 4-l on the adapted doubled mineral medium (Verduyn et al., 1992) with 27.1 g.l-1 of glucose and 1.42 g.l-1 of ethanol, to support a biomass concentration of about 15 g dry weight.l-1. The dilution rate was set to be 0.05 hr-1 and the airflow rate was set to be 200 l.hr-1. Other fermentation parameters are: a pH controlled at 5, a temperature controlled at 30ËC, an overpressure of 0.3 bar and stirrer speed of 600 rpm. The chemostat was considered to obtain its stable steady state condition 5 resident times after the end of its batch phase. Experiment Overall Design: Glucose pulse experiment - At the age of 7 dilution times, the steady state chemostat culture was perturbed by the addition of 20 ml of glucose solution (200 g/l) to the fermentor so that the residual glucose concentration was suddenly increased to about 1 g/l (5.56 mM). The glucose solution was rapidly injected by a pneumatic system (< 1 s). Samples were taken prior to the glucose pulse (steady state samples) and within 360 s transient after the perturbation. Experiment Overall Design: Verduyn,C., Postma,E., Scheffers,W.A., and van Dijken,J.P. (1992). Effect of benzoic acid on metabolic fluxes in yeasts: a continuous-culture study on the regulation of respiration and alcoholic fermentation. Yeast 8, 501-517.
2008-06-12 | E-GEOD-3821 | biostudies-arrayexpress
Project description:Proteomics comparison of wild type Lactococcus lactis MG1363 with a mutant strain that has a point mutation in the global carbon catabolite repression regulator (CcpA) grown under glucose-limited chemostat conditions at D = 0.5 /h.
2021-03-01 | PXD021956 | Pride
Project description:Dynamics of short-term effects of doxorubicin, a chemotherapy agent, on S. cerevisiae cells were investigated. After five residence times at steady-state, Yeast cells in chemostat was introduced a doxorubicin pulse to get 20 µM initial doxorubicin concentration. Samples were collected at steady state and at 1, 5, 10, 15, 20, 25, 30, 60, 90, 120 and 180 minutes after the pulse.
2022-01-12 | E-MTAB-10023 | biostudies-arrayexpress
Project description:Here, we develop a systems-level approach leveraging powerful next generation sequencing, proteomics and phenotypic studies to rapidly obtain an integrated view of lignocellulose degradation in the earliest free living fungi RNA-seq of Piromyces grown on Glucose, Cellulose, Cellulobiose, Avicel, Filter paper, and time-course of transient glucose pulse (catabolite repression). N>=2
2016-02-12 | E-GEOD-64834 | biostudies-arrayexpress
Project description:The Saccharomyces cerevisiae SFP1 is required for proper regulation of ribosome biogenesis and cell size in response to nutrients. A mutant deleted for SFP1 shows specific traits among which a slow growth phenotype, which is particularly evident during growth on glucose. To assess the effects of nutrients on the activity of Sfp1 independent by growth rate related feedback we grew an sfp1Πmutant and its isogenic reference strain in chemostat cultures, at the same specific growth rate, under glucose/ethanol-limitation. Our data show that Sfp1 is involved in the modulation of cell size and RiBi gene expression and that these two functions are differently influenced by nutrients. The continuous cultures were then pulsed with a glucose excess generating a situation of batch growth similar to shake flask cultures. The dynamic analysis of the metabolic and transcriptional response following the glucose addition suggested that Sfp1 plays a role at the crossroads of ribosome biogenesis and central carbon metabolism regulation. Finally, we show that the down-regulation of RP genes, which was observed in an sfp1Πstrain during shake flask growth, cannot be directly ascribed to the absence of Sfp1 but is most probably a secondary effect due to the low growth potential of the mutant strain. Experiment Overall Design: After ten volume changes, few seconds after the samples for the steady state analysis were collected, the anaerobic glucose pulse experiments were started by sparging the medium reservoir and the fermenter with pure nitrogen gas (airflow of 0.5 L min-1, Hoek-Loos, Schiedam, <5 ppm O2). NorpreneTM tubing and butyl septa were used to minimize oxygen diffusion into the anaerobic culture. Two minutes after nitrogen sparging and just before the addition of glucose, the medium and the effluent pumps were switched off. At this time point (which we will refer to as time T=0) the 200 mM glucose pulse was injected aseptically through a rubber septum. Experiment Overall Design: Sampling from chemostats, total RNA extraction, probe preparation and hybridization to Affymetrix Genechip® microarrays were performed as previously described (1). Samples were collected at steady state and then at 5, 10, 30, 60 and 120 minutes after the pulse. The results relative to steady state samples were derived from three independent cultures, those relative to the time course analysis were derived from two independent cultures. Experiment Overall Design: 1) Cipollina C., van den Brink J., Daran-Lapujade P., Pronk J.T., Vai M. and de Winde J.H. (2007) Revisiting the role of yeast Sfp1 in ribosome biogenesis and cell size control: A chemostat study. Microbiology. In press.
2008-06-18 | E-GEOD-9644 | biostudies-arrayexpress
Project description:In contrast to batch cultivation, chemostat cultivation allows the identification of carbon source responses without interference by carbon-catabolite repression, accumulation of toxic products, and differences in specific growth rate. This study focuses on the yeast Saccharomyces cerevisiae, grown in aerobic, carbon-limited chemostat cultures. Genome-wide transcript levels and in vivo fluxes were compared for growth on two sugars, glucose and maltose, and for two C2-compounds, ethanol and acetate. In contrast to previous reports on batch cultures, few genes (180 genes) responded to changes of the carbon source by a changed transcript level. Very few transcript levels were changed when glucose as the growth-limiting nutrient was compared with maltose (33 transcripts), or when acetate was compared with ethanol (16 transcripts). Although metabolic flux analysis using a stoichiometric model revealed major changes in the central carbon metabolism, only 117 genes exhibited a significantly different transcript level when sugars and C2-compounds were provided as the growthlimiting nutrient. Despite the extensive knowledge on carbon source regulation in yeast, many of the carbon source-responsive genes encoded proteins with unknown or incompletely characterized biological functions. In silico promoter analysis of carbon source-responsive genes confirmed the involvement of several known transcriptional regulators and suggested the involvement of additional regulators. Transcripts involved in the glyoxylate cycle and gluconeogenesis showed a good correlation with in vivo fluxes. This correlation was, however, not observed for other important pathways, including the pentose-phosphate pathway, tricarboxylic acid cycle, and, in particular, glycolysis. These results indicate that in vivo fluxes in the central carbon metabolism of S. cerevisiae grown in steadystate, carbon-limited chemostat cultures are controlled to a large extent via post-transcriptional mechanisms. Experiment Overall Design: Cultivation of microorganisms in chemostats offers numerous advantages for studying the structure and regulation of metabolic networks (11). In chemostat cultures, individual culture parameters can be changed, while keeping other relevant physical and chemical culture parameters (composition of synthetic medium, pH, temperature, aeration, etc.) constant. An especially important parameter in this respect is the specific growth rate, which, in a chemostat, is equal to the dilution rate, which can be accurately controlled. This allows the experimenter to investigate the effects of environmental changes or genetic interventions at a fixed specific growth rate, even if these changes result in different specific growth rates in batch cultures. In a chemostat, growth can be limited by a single, selected nutrient. The very low residual concentrations of this growth-limiting nutrient in chemostat cultures alleviate effects of catabolite repression and inactivation. Furthermore, these low residual substrate concentrations prevent substrate toxicity, which, for example, occurs when S. cerevisiae is grown on ethanol or acetate as the carbon source in batch cultures . Experiment Overall Design: The central goal of the present study is to assess to what extent carbon source-dependent regulation of fluxes through central carbon metabolism in S. cerevisiae is regulated at the level of transcription. To this end, we compare the transcriptome of carbon-limited, aerobic chemostat cultures grown on four different carbon sources: glucose, maltose, ethanol, and acetate. Data from the transcriptome analysis are compared with flux distribution profiles calculated with a stoichiometric metabolic network model. Questions that will be addressed are as follows: (i) does glucose-limited aerobic cultivation lead to a complete alleviation of glucose-catabolite repression; (ii) how (in)complete is our understanding of the genes involved in the transcriptional response of S. cerevisiae to four of the most common carbon sources for this yeast; and (iii) to what extent do transcriptome analyses with microarrays provide a reliable indication of flux distribution in metabolic networks?
2008-06-16 | E-GEOD-8895 | biostudies-arrayexpress
Project description:The purpose of this study was to characterize carbon metabolism and gene regulation in Alicyclobacillus acidocaldarius during growth on monosaccharides in an effort to determine whether carbon catabolite repression was active. Chemostat studies and global transcriptome analysis were used to accomplish this goal.
2016-08-31 | GSE84032 | GEO
Project 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 âsignatureâ transcripts for anaerobicity under dynamic as well as under steady state conditions Experiment Overall Design: To invoke rapid and full induction of fermentative capacity, respiratory, aerobic glucose-limited chemostat cultures (D=0.1â¢h-1) were shifted to fully fermentative conditions by sudden depletion of oxygen and addition of glucose. The glucose was added two min after sparging the continuous culture with pure nitrogen, when the dissolved oxygen concentration had decreased from 75-80% to 10-15% of air saturation. Samples for micro-arrays were taken for each time point after the perturbation (5, 10, 30, 60 and 120 min) from two independently cultured replicates, while steady state data were taken from three independent chemostats. The complete dataset therefore comprised 13 samples.
2008-10-18 | E-GEOD-8187 | biostudies-arrayexpress
Project description:Chemostat cultivation mode imposes selective pressure on cells, which may result slow adaptation in the physiological state over time. We applied a two-compartment scale-down chemostat system simulating glucose gradients to characterize the long-term (100’s of hours) response of S. cerevisiae to fluctuating glucose concentrations. A wild-type strain and a recombinant strain, expressing an insulin precursor, were cultured in the scale-down system, and analyzed at the physiological and proteomic level. Phenotypes of both strains were compared to those observed in a well-mixed single chemostat system.
2020-06-09 | PXD015536 | Pride
Project description:Glucose Pulse to sfp1delta continuous cultures
| PRJNA103505 | ENA