This study examines the mechanisms underlying fumarate- and glyoxylate-mediated changes in tobraymcyin sensitivity in PAO1 cells
Carbon Sources Tune Antibiotic Susceptibility in Pseudomonas aeruginosa via Tricarboxylic Acid Cycle Control.
No sample metadata fields
View SamplesA cross sectional study using data collected at the time of liver biopsy, the final eligibility assessment for participation in iWITH (NCT01638559), an immunosuppression withdrawal trial.
Evidence of Chronic Allograft Injury in Liver Biopsies From Long-term Pediatric Recipients of Liver Transplants.
Specimen part
View SamplesDeeper understanding of antibiotic-induced physiological responses is critical to identifying means for enhancing our current antibiotic arsenal. Bactericidal antibiotics with diverse targets have been hypothesized to kill bacteria, in part, by inducing production of damaging reactive species. This notion has been supported by many groups, but recently challenged. Here we robustly test the hypothesis using biochemical, enzymatic and biophysical assays along with genetic and phenotypic experiments. We first used a novel intracellular hydrogen peroxide (H2O2) sensor, together with a chemically diverse panel of fluorescent dyes sensitive to an array of reactive species, to demonstrate that antibiotics broadly induce redox stress. Subsequent gene expression analyses reveal that complex antibiotic-induced oxidative stress responses are distinct from canonical responses generated by supra-physiological levels of H2O2. We next developed a method to dynamically quantify cellular respiration and found that bactericidal antibiotics elevate oxygen consumption, indicating significant alterations to bacterial redox physiology. We further show that catalase or DNA mismatch repair enzyme overexpression, as well as antioxidant pre-treatment limit antibiotic lethality, indicating that reactive oxygen species causatively contribute to antibiotic killing. Critically, the killing efficacy of antibiotics was diminished under strict anaerobic conditions, but could be enhanced by exposure to molecular oxygen or addition of alternative electron acceptors, suggesting that environmental factors play a role in killing cells physiologically primed for death. This work provides direct evidence that bactericidal antibiotics, downstream of their target-specific interactions, induce complex redox alterations that contribute to cellular damage and death, thus supporting an evolving, expanded model of antibiotic lethality.
Antibiotics induce redox-related physiological alterations as part of their lethality.
Treatment
View SamplesAlthough transcriptional programs associated with T-cell specification and commitment have been described, the functional hierarchy and the roles of key regulators in structuring/ orchestrating these programs remain unclear. Activation of Notch signaling in uncommitted precursors by the thymic stroma initiates the T-cell differentiation program. One regulator first induced in these precursors is the DNA binding protein Tcf-1, a T-cell specific mediator of Wnt signaling. Yet the specific contribution of Tcf-1 to early T-cell development and the signals inducing it in these cells remain unclear. Here we assign functional significance to Tcf-1 as a gatekeeper of T-cell fate. We show that Tcf-1 is directly activated by Notch signals. Tcf-1 is required at the earliest phase of Tcell determination for progression beyond the early thymic progenitor (ETP) stage. The global expression profile of Tcf-1 deficient progenitors indicates that basic processes of DNA metabolism are downregulated in its absence and the blocked T-cell progenitors become abortive and die by apoptosis. Our data thus add an important functional relationship to the roadmap of T-cell development.
T-cell factor 1 is a gatekeeper for T-cell specification in response to Notch signaling.
Specimen part
View SamplesWe report that in developing B cells individual enhancers of Igk make up super-enhancer cluster where contacts between its components rely on all constituents. Reduction of interaction frequency in enhancer knock-out cells is associated with deminished transcriptional output of enhancers and Igk locus. Moreover, we find that Igk enhancer MiEk has an effect on levels of CBFb enrichment on Tcrb enhancer, Eb afffecting Tcrb recombination and T cell development. Overall design: Examination of expression, chromatin accessibility, histone modifications and nuclear organization in developing wild-type and Igk and Tcrb enhancer deficient B and T lymphocytes.
Active and Inactive Enhancers Cooperate to Exert Localized and Long-Range Control of Gene Regulation.
Specimen part, Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
In vivo mapping of notch pathway activity in normal and stress hematopoiesis.
Sex, Age, Specimen part
View SamplesNotch signaling defines a conserved, fundamental pathway, responsible for determination in metazoan development and is widely recognized as an essential component of lineage specific differentiation and stem cell self-renewal in many tissues including the hematopoietic system. Until recently, the majority of studies in the hematopoietic system focused on Notch signaling in lymphocyte differentiation and knowledge of individual Notch receptor roles in early hematopoiesis has been limited due to a paucity of genetic tools available To fate-map Notch receptor expression and pathway activity in the hematopoietic system we used tamoxifen-inducible CreER knock-in mice for individual Notch receptors in combination to a novel Notch reporter strain (Hes1GFP) and a conditional gain of function allele of Notch2 receptor (Rosa-lsl-ICN2).
In vivo mapping of notch pathway activity in normal and stress hematopoiesis.
Sex, Age, Specimen part
View SamplesNotch signaling defines a conserved, fundamental pathway, responsible for determination in metazoan development and is widely recognized as an essential component of lineage specific differentiation and stem cell self-renewal in many tissues including the hematopoietic system. Until recently, the majority of studies in the hematopoietic system focused on Notch signaling in lymphocyte differentiation and knowledge of individual Notch receptor roles in early hematopoiesis has been limited due to a paucity of genetic tools available To fate-map Notch receptor expression and pathway activity in the hematopoietic system we used tamoxifen-inducible CreER knock-in mice for individual Notch receptors in combination to a novel Notch reporter strain (Hes1GFP) and a conditional gain of function allele of Notch2 receptor (Rosa-lsl-ICN2).
In vivo mapping of notch pathway activity in normal and stress hematopoiesis.
Sex, Age, Specimen part
View SamplesNotch signaling defines a conserved, fundamental pathway, responsible for determination in metazoan development and is widely recognized as an essential component of lineage specific differentiation and stem cell self-renewal in many tissues including the hematopoietic system. Until recently, the majority of studies in the hematopoietic system focused on Notch signaling in lymphocyte differentiation and knowledge of individual Notch receptor roles in early hematopoiesis has been limited due to a paucity of genetic tools available To fate-map Notch receptor expression and pathway activity in the hematopoietic system we used tamoxifen-inducible CreER knock-in mice for individual Notch receptors in combination to a novel Notch reporter strain (Hes1GFP) and a conditional gain of function allele of Notch2 receptor (Rosa-lsl-ICN2).
In vivo mapping of notch pathway activity in normal and stress hematopoiesis.
Sex, Age, Specimen part
View SamplesNotch signaling defines a conserved, fundamental pathway, responsible for determination in metazoan development and is widely recognized as an essential component of lineage specific differentiation and stem cell self-renewal in many tissues including the hematopoietic system. Until recently, the majority of studies in the hematopoietic system focused on Notch signaling in lymphocyte differentiation and knowledge of individual Notch receptor roles in early hematopoiesis has been limited due to a paucity of genetic tools available To fate-map Notch receptor expression and pathway activity in the hematopoietic system we used tamoxifen-inducible CreER knock-in mice for individual Notch receptors in combination to a novel Notch reporter strain (Hes1GFP) and a conditional gain of function allele of Notch2 receptor (Rosa-lsl-ICN2).
In vivo mapping of notch pathway activity in normal and stress hematopoiesis.
Sex, Specimen part
View Samples