Cell membrane-derived lysophosphatidylcholine activates cardiac ryanodine receptor channels

Lysophosphatidylcholine (LPC) is metabolized from a membrane phospholipid and modulates a variety of channels in the plasma membrane (PM). We examined LPC modulation of cardiac ryanodine receptor (RyR) channels in the sarcoplasmic reticulum (SR) using the planar lipid bilayer method to measure the single-channel currents. Micromolar concentrations of LPC increased the open probability of the reconstituted RyR channels irrespective of whether LPC was added to the cis or trans chamber. LPC also increased the membrane capacitance of the bilayer. The effects of LPC contrasted well with those of sphingosylphosphorylcholine (SPC). Taken together, these results suggest that amphipathic lipid LPC does not bind directly to the RyR channel protein, but rather, is incorporated into the bilayer membrane and activates the channel. Thus, we consider cell membrane-derived LPC to be a putative endogenous mediator that activates not only plasma membrane channels but also RyR channels and induces arrhythmogenic Ca²⁺ mobilization in cardiomyocytes.     

Total syntheses of schizandriside,saracoside and (±)-isolariciresinol with antioxidant activities

Lignans are widely distributed in plants and exhibit significant pharmacological effects, including anti-tumor and antioxidative activities. Here, we describe the total synthesis of schizandriside (1), a compound we previously isolated from Saraca asoca by monitoring antioxidative activity using the 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay. Starting from a tandem Michael-aldol reaction, the lignan skeleton was synthesized in 6 steps, including a cyclization step. To determine the stereochemistry of 1, we synthesized the natural product (±)-isolariciresinol (18) from alcohol 17. Comparison of the spectral data showed good agreement. Glycosylation was investigated using four different glycosyl donors. Only the Koenigs–Knorr condition using silver trifluoromethanesulfonate with 1,1,3,3-tetramethylurea provided the glycosylated product. Deprotection and purification using reverse-phase high-performance liquid chromatography gave schizandriside (1) and its diastereomer saracoside (2). Synthesized 1, 2 and 18 showed antioxidant activity with IC₅₀?=?34.4, 28.8, 53.0 μM, respectively.     

Dehydropropylpantothenamide isolated by a co-culture of Nocardia tenerifensis IFM 10554T in the presence of animal cells

Journal of Natural Medicines - A new amide, named dehydropropylpantothenamide (1), was obtained by a co-culture of Nocardia tenerifensis IFM 10554T in the presence of the mouse macrophage-like cell...     

Analysis of blink activity and anomalous eyelid movements in patients with hemifacial spasm

Graefe's Archive for Clinical and Experimental Ophthalmology - To assess spontaneous blinking and anomalous eyelid movements in patients with hemifacial spasm with an emphasis on interocular...     

A simple and practical workflow for genotyping of CRISPR–Cas9‐based knockout phenotypes using multiplexed amplicon sequencing

Founder animals carrying high proportions of somatic mutation induced by CRISPR–Cas9 enable a rapid and scalable strategy for the functional screening of numerous target genes in vivo. In this functional screening, genotyping using pooled amplicons with next‐generation sequencing is the most suitable approach for large‐scale management of multiple samples and accurate evaluation of the efficiency of Cas9‐induced somatic mutations at target sites. Here, we present a simple workflow for genotyping of multiple CRISPR–Cas9‐based knockout founders by pooled amplicon sequencing. Using custom barcoded primers, pooled amplicons from multiple individuals can be run in a single‐indexed library on the Illumina MiSeq platform. Additionally, a user‐friendly web tool, CLiCKAR, is available to simultaneously perform demultiplexing of pooled sequence data and evaluation of somatic mutation in each phenotype. CLiCKAR provides users with practical reports regarding the positions of insertions/deletions, as well as the frameshift ratio and tables containing mutation sequences, and read counts of each phenotype, with just a few clicks by the implementation of demultiplexing for pooled sample data and calculation of the frameshift ratio. This genotyping workflow can be harnessed to evaluate genotype–phenotype correlations in CRISPR–Cas9‐based loss‐of‐function screening of numerous target genes in various organisms.