EF4 knockout E. coli cells exhibit lower levels of cellular biosynthesis under acidic stress.
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ABSTRACT:
SUBMITTER: Yang F
PROVIDER: S-EPMC4085283 | biostudies-literature | 2014 Jul
REPOSITORIES: biostudies-literature
Publications
EF4 knockout E. coli cells exhibit lower levels of cellular biosynthesis under acidic stress.
Yang Fang F Li Zhikai Z Hao Jia J Qin Yan Y
Protein & cell 20140701 7
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Project description:Purpose: We use the gene expression data to estimate the effects of tetracycline on gene expression and average ribosome density. Methods: The mRNAs were extracted with TRIzol reagent. The mRNAs were fragmented into 280 bp and the sequencing process was conducted on HiSeq 2500 platform. We use cutadapt, bowtie2, Plastid and DEseq2 software to analyze the expression levels of genes in two Escherichia coli strains. Results: The gene expression in EF4 knockout Escherichia coli strain was similar with BW25113 strain under normal condition. Under tetracycline treatment, many genes' expression were differentially regulated. Interestingly, we found that the gene expression of ribosomal proteins was up-regulated in WT strain comparing with EF4 knockout E. coli strain. Conclusions: Our results suggest that EF4 affects the average ribosome density and global gene expression in two Escherichia coli strain under tetracycline treatment.
2021-01-09 | GSE109025 | GEO
Project description:BackgroundThe phosphorus compounds serve as major building blocks of many biomolecules, and have important roles in signal transduction. The phosphate is involved in many biochemical reactions by the transfer of phosphoryl groups. All living cells sophisticatedly regulate the phosphate uptake, and survive even under phosphate-limiting condition, and thus phosphate metabolism is closely related to the diverse metabolism including energy and central carbon metabolism. In particular, phosphorylation may play important roles in the metabolic regulation at acidic condition and nitrogen limiting condition, which typically appears at the late growth phase in the batch culture. Moreover, phosphate starvation is a relatively inexpensive means of gene induction in practice, and the phoA promoter has been used for overexpression of heterologous genes. A better understanding of phosphate regulation would allow for optimization of such processes.ResultsThe effect of phosphate (P) concentration on the metabolism in Escherichia coli was investigated in terms of fermentation characteristics and gene transcript levels for the aerobic continuous culture at the dilution rate of 0.2 h-1. The result indicates that the specific glucose consumption rate and the specific acetate production rate significantly increased, while the cell concentration decreased at low P concentration (10% of the M9 medium). The increase in the specific glucose uptake rate may be due to ATP demand caused by limited ATP production under P-limitation. The lower cell concentration was also caused by less ATP production. The less ATP production by H+-ATPase may have caused less cytochrome reaction affecting in quinone pool, and caused up-regulation of ArcA/B, which repressed TCA cycle genes and caused more acetate production. In the case of phoB mutant (and also phoR mutant), the fermentation characteristics were less affected by P-limitation as compared to the wild type where the PhoB regulated genes were down-regulated, while phoR and phoU changed little. The phoR gene knockout caused phoB gene to be down-regulated as well as PhoB regulated genes, while phoU and phoM changed little. The effect of pH together with lower P concentration on the metabolic regulation was also investigated. In accordance with up-regulation of arcA gene expression, the expressions of the TCA cycle genes such as sdhC and mdh were down-regulated at acidic condition. The gene expression of rpoS was up-regulated, and the expression of gadA was up-regulated at pH 6.0. In accordance with this, PhoB regulated genes were up-regulated in the wild type under P-rich and P-limited conditions at pH 6.0 as compared to those at pH 7.0. Moreover, the effect of nitrogen limitation on the metabolic regulation was investigated, where the result indicates that phoB gene was up-regulated, and PhoB regulated genes were also up-regulated under N-limitation, as well as nitrogen-regulated genes.ConclusionThe present result shows the complicated nature of the metabolic regulation for the fermentation characteristics upon phosphate limitation, acidic condition, and nitrogen limitation based on the transcript levels of selected genes. The result implies that the regulations under phosphate limitation, acidic condition, and nitrogen limitation, which occur typically at the late growth phase of the batch culture, are interconnected through RpoS and RpoD together with Pho genes.
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Project description:ObjectiveA previous genome-wide association study linked overexpression of an ATP-binding cassette transporter, ABCC5, in humans with a susceptibility to developing type 2 diabetes with age. Specifically, ABCC5 gene overexpression was shown to be strongly associated with increased visceral fat mass and reduced peripheral insulin sensitivity. Currently, the role of ABCC5 in diabetes and obesity is unknown. This study reports the metabolic phenotyping of a global Abcc5 knockout mouse.MethodsA global Abcc5-/- mouse was generated by CRISPR/Cas9. Fat mass was determined by weekly EchoMRI and fat pads were dissected and weighed at week 18. Glucose homeostasis was ascertained by an oral glucose tolerance test, intraperitoneal glucose tolerance test, and intraperitoneal insulin tolerance test. Energy expenditure and locomotor activity were measured using PhenoMaster cages. Glucagon-like peptide 1 (GLP-1) levels in plasma, primary gut cell cultures, and GLUTag cells were determined by enzyme-linked immunosorbent assay.ResultsAbcc5-/- mice had decreased fat mass and increased plasma levels of GLP-1, and they were more insulin sensitive and more active. Recombinant overexpression of ABCC5 protein in GLUTag cells decreased GLP-1 release.ConclusionsABCC5 protein expression levels are inversely related to fat mass and appear to play a role in the regulation of GLP-1 secretion from enteroendocrine cells.
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