6 research outputs found
Imaging Mismatch Repair and Cellular Responses to DNA Damage in Bacillus subtilis
Both prokaryotes and eukaryotes respond to DNA damage through a complex set of physiological changes. Alterations in gene expression, the redistribution of existing proteins, and the assembly of new protein complexes can be stimulated by a variety of DNA lesions and mismatched DNA base pairs. Fluorescence microscopy has been used as a powerful experimental tool for visualizing and quantifying these and other responses to DNA lesions and to monitor DNA replication status within the complex subcellular architecture of a living cell. Translational fusions between fluorescent reporter proteins and components of the DNA replication and repair machinery have been used to determine the cues that target DNA repair proteins to their cognate lesions in vivo and to understand how these proteins are organized within bacterial cells. In addition, transcriptional and translational fusions linked to DNA damage inducible promoters have revealed which cells within a population have activated genotoxic stress responses. In this review, we provide a detailed protocol for using fluorescence microscopy to image the assembly of DNA repair and DNA replication complexes in single bacterial cells. In particular, this work focuses on imaging mismatch repair proteins, homologous recombination, DNA replication and an SOS-inducible protein in Bacillus subtilis. All of the procedures described here are easily amenable for imaging protein complexes in a variety of bacterial species
Quantum-statistical transport phenomena in memristive computing architectures
The advent of reliable, nanoscale memristive components is promising for next
generation compute-in-memory paradigms, however, the intrinsic variability in
these devices has prevented widespread adoption. Here we show coherent electron
wave functions play a pivotal role in the nanoscale transport properties of
these emerging, non-volatile memories. By characterizing both filamentary and
non-filamentary memristive devices as disordered Anderson systems, the
switching characteristics and intrinsic variability arise directly from the
universality of electron transport in disordered media. Our framework suggests
localization phenomena in nanoscale, solid-state memristive systems are
directly linked to circuit level performance. We discuss how quantum
conductance fluctuations in the active layer set a lower bound on device
variability. This finding implies there is a fundamental quantum limit on the
reliability of memristive devices, and electron coherence will play a decisive
role in surpassing or maintaining Moore's Law with these systems.Comment: 13 pages, 6 figure