Electrochemical comparison between IrO2 prepared by anodic oxidation of pure iridium and IrO2 prepared by thermal decomposition of H2IrC16 precursor solution

Surface redox activities, oxygen evolution reaction (OER), oxidation of formic acid (FA), and anodic stability were investigated and compared for IrO2 electrodes prepared by two techniques: the thermal decomposition of H2IrCl6 precursor (TDIROF) and the anodic oxidation of metallic iridium (AIROF). Surface redox activities involved on the AIROF were found to be much faster than those involved on the TDIROF. Concerning the oxygen evolution reaction, both films show a similar mechanism and specific electrocatalytic activities. The situation seems to be different for FA oxidation. In fact, on TDIROF, the oxidation of FA and the OER compete involving the same surface redox couple Ir(VI)/Ir(IV) contrary to FA oxidation on AIROF, where the Ir(V)/Ir(IV) surface redox couple is involved. Finally, electrode stability measurements have shown that contrary to TDIROF, which are very stable under anodic polarization, the AIROF are rapidly corroded under anodic treatment. This corrosion is enhanced even further in the presence of formic acid

Immunopeptidomics toolkit library (IPTK): a python-based modular toolbox for analyzing immunopeptidomics data

Background The human leukocyte antigen (HLA) proteins play a fundamental role in the adaptive immune system as they present peptides to T cells. Mass-spectrometry-based immunopeptidomics is a promising and powerful tool for characterizing the immunopeptidomic landscape of HLA proteins, that is the peptides presented on HLA proteins. Despite the growing interest in the technology, and the recent rise of immunopeptidomics-specific identification pipelines, there is still a gap in data-analysis and software tools that are specialized in analyzing and visualizing immunopeptidomics data. Results We present the IPTK library which is an open-source Python-based library for analyzing, visualizing, comparing, and integrating different omics layers with the identified peptides for an in-depth characterization of the immunopeptidome. Using different datasets, we illustrate the ability of the library to enrich the result of the identified peptidomes. Also, we demonstrate the utility of the library in developing other software and tools by developing an easy-to-use dashboard that can be used for the interactive analysis of the results. Conclusion IPTK provides a modular and extendable framework for analyzing and integrating immunopeptidomes with different omics layers. The library is deployed into PyPI at https://pypi.org/project/IPTKL/ and into Bioconda at https://anaconda.org/bioconda/iptkl , while the source code of the library and the dashboard, along with the online tutorials are available at https://github.com/ikmb/iptoolkit

Oligodendrocyte Neurofascin independently regulates both myelin targeting and sheath growth in the CNS

Selection of the correct targets for myelination and regulation of myelin sheath growth are essential for central nervous system (CNS) formation and function. Through a genetic screen in zebrafish and complementary analyses in mice, we find that loss of oligodendrocyte Neurofascin leads to mistargeting of myelin to cell bodies, without affecting targeting to axons. In addition, loss of Neurofascin reduces CNS myelination by impairing myelin sheath growth. Time-lapse imaging reveals that the distinct myelinating processes of individual oligodendrocytes can engage in target selection and sheath growth at the same time and that Neurofascin concomitantly regulates targeting and growth. Disruption to Caspr, the neuronal binding partner of oligodendrocyte Neurofascin, also impairs myelin sheath growth, likely reflecting its association in an adhesion complex at the axon-glial interface with Neurofascin. Caspr does not, however, affect myelin targeting, further indicating that Neurofascin independently regulates distinct aspects of CNS myelination by individual oligodendrocytes in vivo

Determinants of Bacteriophage 933W Repressor DNA Binding Specificity

We reported previously that 933W repressor apparently does not cooperatively bind to adjacent sites on DNA and that the relative affinities of 933W repressor for its operators differ significantly from that of any other lambdoid bacteriophage. These findings indicate that the operational details of the lysis-lysogeny switch of bacteriophage 933W are unique among lambdoid bacteriophages. Since the functioning of the lysis-lysogeny switch in 933W bacteriophage uniquely and solely depends on the order of preference of 933W repressor for its operators, we examined the details of how 933W repressor recognizes its DNA sites. To identify the specificity determinants, we first created a molecular model of the 933W repressor-DNA complex and tested the predicted protein-DNA interactions. These results of these studies provide a picture of how 933W repressor recognizes its DNA sites. We also show that, opposite of what is normally observed for lambdoid phages, 933W operator sequences have evolved in such a way that the presence of the most commonly found base sequences at particular operator positions serves to decrease, rather than increase, the affinity of the protein for the site. This finding cautions against assuming that a consensus sequence derived from sequence analysis defines the optimal, highest affinity DNA binding site for a protein