New distributional record of Cylindera (Oligoma) paradoxa (W. Horn, 1892) (Coleoptera: Cicindelidae) in Ratnapura District, Sri Lanka

Since the 19th century, Cylindera (Oligoma) paradoxa (W. Horn, 1892) has been recorded from only 10 locations in Sri Lanka, with only 2 of those recorded in the past 30 years. We recently found this species in the Keeragala estate (Ratnapura District) during field surveys. Our new record fills a gap in the knowledge of this species’ distribution in Sri Lanka

New distributional record of Cylindera (Oligoma) paradoxa (W. Horn, 1892) (Coleoptera: Cicindelidae) in Ratnapura District, Sri Lanka

Since the 19th century, Cylindera (Oligoma) paradoxa (W. Horn, 1892) has been recorded from only 10 locations in Sri Lanka, with only 2 of those recorded in the past 30 years. We recently found this species in the Keeragala estate (Ratnapura District) during field surveys. Our new record fills a gap in the knowledge of this species' distribution in Sri Lanka

Force-induced motions of the PIEZO1 blade probed with fluorimetry

Summary: Mechanical forces are thought to activate mechanosensitive PIEZO channels by changing the conformation of a large transmembrane blade domain. Yet, whether different stimuli induce identical conformational changes in this domain remains unclear. Here, we repurpose a cyclic permuted green fluorescent protein as a conformation-sensitive probe to track local rearrangements along the PIEZO1 blade. Two independent probes, one inserted in an extracellular site distal to the pore and the other in a distant intracellular proximal position, elicit sizable fluorescence signals when the tagged channels activate in response to fluid shear stress of low intensity. Neither cellular indentations nor osmotic swelling of the cell elicit detectable fluorescence signals from either probe, despite the ability of these stimuli to activate the tagged channels. High-intensity flow stimuli are ineffective at eliciting fluorescence signals from either probe. Together, these findings suggest that low-intensity fluid shear stress causes a distinct form of mechanical stress to the cell

Psoralea corylifolia extract induces vasodilation in rat arteries through both endothelium-dependent and -independent mechanisms involving inhibition of TRPC3 channel activity and elaboration of prostaglandin

Context: Fructus Psoralea, Psoralea corylifolia L. (Leguminosae), has been widely used in traditional medicines for the treatment of dermatitis, leukoderma, asthma and osteoporosis. Objectives: In this study, we sought to study mechanisms underlying the vasoactive properties of Psoralea corylifolia extract (PCE) and its active ingredients. Materials and methods: To study mechanisms underlying the vasoactive properties of PCE prepared by extracting dried seeds of Psoralea corylifolia with 70% ethanol, isometric tension recordings of rat aortic rings and the ionic currents through TRPC3 (transient receptor potential canonical 3) channels were measured with the cumulative concentration (10–600 μg/mL) of PCE or its constituents. Results: Cumulative treatment with PCE caused the relaxation of pre-contracted aortic rings in the presence and absence of endothelium with EC50 values of 61.27 ± 3.11 and 211.13 ± 18.74 μg/mL, respectively. Pretreatment with inhibitors of nitric oxide (NO) synthase, guanylate cyclase, or cyclooxygenase and pyrazole 3, a selective TRPC3 channel blocker, significantly decreased PCE-induced vasorelaxation (p < 0.01). The PCE constituents, bakuchiol, isobavachalcone, isopsoralen and psoralen, inhibited hTRPC3 currents (inhibited by 40.6 ± 2.7, 27.1 ± 7.9, 35.1 ± 4.8 and 47.4 ± 3.9%, respectively). Furthermore, these constituents significantly relaxed pre-contracted aortic rings (EC50 128.9, 4.5, 32.1 and 114.9 μg/mL, respectively). Discussion and conclusions: Taken together, our data indicate that the vasodilatory actions of PCE are dependent on endothelial NO/cGMP and also involved in prostaglandin production. PCE and its active constituents, bakuchiol, isobavachalcone, isopsoralen and psoralen, caused dose-dependent inhibition of TRPC3 channels, indicating that those ingredients attenuate Phe-induced vasoconstriction

Distinct gating mechanism of SOC channel involving STIM-Orai coupling and an intramolecular interaction of Orai in Caenorhabditis elegans

Store-operated calcium entry (SOCE), an important mechanism of Ca2+ signaling in a wide range of cell types, is mediated by stromal interaction molecule (STIM), which senses the depletion of endoplasmic reticulum Ca2+ stores and binds and activates Orai channels in the plasma membrane. This inside-out mechanism of Ca2+ signaling raises an interesting question about the evolution of SOCE: How did these two proteins existing in different cellular compartments evolve to interact with each other? We investigated the gating mechanism of Caenorhabditis elegans Orai channels. Our analysis revealed a mechanism of Orai gating by STIM binding to the intracellular 2-3 loop of Orai in C. elegans that is radically different from Orai gating by STIM binding to the N and C termini of Orai in mammals. In addition, we found that the conserved hydrophobic amino acids in the 2-3 loop of Orai1 are important for the oligomerization and gating of channels and are regulated via an intramolecular interaction mechanism mediated by the N and C termini of Orai1. This study identifies a previously unknown SOCE mechanism in C. elegans and suggests that, while the STIM-Orai interaction is conserved between invertebrates and mammals, the gating mechanism for Orai channels differs considerably