Publications by authors named "Elizabeth A Libby"
At the single-cell level, protein kinase activity is typically inferred from downstream transcriptional reporters. However, promoters are often coregulated by several pathways, making the activity of a specific kinase difficult to deconvolve. Here, we present modular, direct, and specific sensors of bacterial kinase activity, including FRET-based sensors, as well as a synthetic transcription factor based on the lactose repressor (LacI) that has been engineered to respond to phosphorylation.
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- Isogenic populations of cells show differences in antibiotic tolerance that may either be random or regulated.
- Researchers identified that the gene sasA in Bacillus subtilis, responsible for (p)ppGpp synthesis, varies in expression due to complex regulation involving multisite phosphorylation.
- This regulation is significant as it controls the occurrence of rare cells with high sasA expression that are more tolerant to antibiotics, supporting that phosphorylation can effectively manage antibiotic resistance variability.
How do neighboring bacterial biofilms sense and communicate with each other? In a recent paper, Liu et al. (2017) demonstrate how electrical signaling allows communication of metabolic states between adjacent B. subtilis biofilms, providing a possible generalizable mechanism for communication in multispecies biofilms with interdependent metabolism.
View Article and Find Full Text PDFβ-Lactams represent one of the most important classes of antibiotics discovered to date. These agents block Lipid II processing and cell wall biosynthesis through inactivation of penicillin-binding proteins (PBPs). PBPs enzymatically load cell wall building blocks from Lipid II carrier molecules onto the growing cell wall scaffold during growth and division.
View Article and Find Full Text PDFMost bacteria contain both eukaryotic-like Ser/Thr kinases (eSTKs) and eukaryotic-like Ser/Thr phosphatases (eSTPs). Their role in bacterial physiology is not currently well understood in large part because the conditions where the eSTKs are active are generally not known. However, all sequenced Gram-positive bacteria have a highly conserved eSTK with extracellular PASTA repeats that bind cell wall derived muropeptides.
View Article and Find Full Text PDFMembrane protein expression triggers chromosomal locus repositioning in bacteria.
Proc Natl Acad Sci U S A
May 2012
Article Synopsis
- Researchers found that the expression of membrane proteins in E. coli influences the positioning of related chromosomal loci, causing them to move toward the membrane when induced.
- In contrast, the expression of cytoplasmic proteins or mutations that stop translation did not trigger this repositioning, suggesting a specific link between membrane proteins and chromosomal location.
- The repositioning process is quick and can affect chromosomal areas up to 90 kb away, indicating that membrane protein expression is crucial for maintaining a dynamic organization of the bacterial chromosome.
Objectives: To describe the quality of warfarin prescribing and monitoring in Veterans Affairs (VA) nursing homes and to assess the factors associated with maintaining a therapeutic international normalized ratio (INR).
Design: Retrospective cohort.
Setting: Five VA nursing homes.
Previously, an unexplained subcellular localization was reported for a functional fluorescent protein fusion to the response regulator OmpR in Escherichia coli. The pronounced regions of increased fluorescence, or foci, are dependent on OmpR phosphorylation and do not occupy fixed, easily identifiable positions, such as the poles or mid-cell. Here we show that the foci are due to OmpR-YFP (yellow fluorescent protein) fusion binding to specific sites in the chromosome.
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