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Title: Transition from succinate to methanol growth in Methylobacterium Extorquens AM1      
dateReleased:
07-31-2011
description:
In order to provide information about the gene expression response that occurs when cells experience a change in carbon source, succinate limited chemostat cultures of Methylobacterium extorquens AM1 were grown to and maintained at an OD of ~0.63, transferred to flasks and methanol was added. Cells were harvested for RNA extraction at time: 0 min, 10 min, 30 min, 1 hr, 2 hr, 4 hr and 6 hr post transition. At 30 min, a no methanol addition sample was extracted as a carbon starvation control. These data were used in conjunction with flux, enzymatic and metabolite measurements to assess the changes in central metabolism during this transition. Abstract from manuscript: When organisms experience environmental change, how does their metabolic network reset and adapt to the new condition? This study focused on the mechanisms of metabolic adaptation occurring during the transition from succinate to methanol growth by the methylotrophic bacterium Methylobacterium extorquens, analyzing changes in carbon flux, gene expression, metabolites and enzymatic activities over time. Initially, cells experienced metabolic imbalance with excretion of metabolites, changes in nucleotide levels and cessation of cell growth. Though assimilatory pathways were induced rapidly, a transient block in carbon flow to biomass synthesis occurred, and enzymatic assays suggested methylenetetrahydrofolate dehydrogenase as one control point. This “downstream priming” mechanism ensures that significant carbon flux through these pathways does not occur until they are fully induced, precluding the buildup of toxic intermediates. Most metabolites that are required for growth on both carbon sources did not change significantly, even though transcripts and enzymatic activities required for their production changed radically, underscoring the concept of metabolic setpoints. Gene expression in succinate limited chemostat cultures was compared to gene expression in cells transferred to flasks before and after methanol addition. As a control, a time = 0 sample (RNA prepared from cells harvested directly from the chemostat) was compared to a time = 0 sample immediately obtained after the cells were transferred to flasks, before methanol was added in order to identify changes due to flask transfer. A carbon starvation control was also done comparing expression from time = 0 (chemostat cells) to cells transferred to flasks for 30 min with no carbon source added. Two biological replicates each with two techinal replicates (dye swap) were analyzed for time = 0 (chemostat) vs 10 min, 30 min, 1 hr and 2 hr after methanol addition. One biological replicate with two technical replicates (dye swap) were analyzed for time = 0 (chemostat) vs time = 0 (flask transfer), and time = 0 (chemostat) vs time = 4 hr, 6 hr and 30 min no methanol addition.
privacy:
not applicable
aggregation:
instance of dataset
ID:
E-GEOD-22031
refinement:
raw
alternateIdentifiers:
22031
keywords:
functional genomics
dateModified:
05-02-2014
availability:
available
types:
gene expression
name:
Methylobacterium extorquens AM1
ID:
A-GEOD-6262
name:
UW Lidstrom Methylobacterium extorquens AM1 11K v1.0
accessURL: https://www.ebi.ac.uk/arrayexpress/files/E-GEOD-22031/E-GEOD-22031.raw.1.zip
storedIn:
ArrayExpress
qualifier:
gzip compressed
format:
TXT
accessType:
download
authentication:
none
authorization:
none
accessURL: https://www.ebi.ac.uk/arrayexpress/files/E-GEOD-22031/E-GEOD-22031.processed.1.zip
storedIn:
ArrayExpress
qualifier:
gzip compressed
format:
TXT
accessType:
download
authentication:
none
authorization:
none
accessURL: https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE22031
storedIn:
Gene Expression Omnibus
qualifier:
not compressed
format:
HTML
accessType:
landing page
primary:
true
authentication:
none
authorization:
none
abbreviation:
EBI
homePage: http://www.ebi.ac.uk/
ID:
SCR:004727
name:
European Bioinformatics Institute
homePage: https://www.ebi.ac.uk/arrayexpress/
ID:
SCR:002964
name:
ArrayExpress