Nonmuscle Myosin II helps regulate synaptic vesicle mobility at the Drosophila neuromuscular junction

<p>Abstract</p> <p>Background</p> <p>Although the mechanistic details of the vesicle transport process from the cell body to the nerve terminal are well described, the mechanisms underlying vesicle traffic within nerve terminal boutons is relatively unknown. The actin cytoskeleton has been implicated but exactly how actin or actin-binding proteins participate in vesicle movement is not clear.</p> <p>Results</p> <p>In the present study we have identified Nonmuscle Myosin II as a candidate molecule important for synaptic vesicle traffic within <it>Drosophila </it>larval neuromuscular boutons. Nonmuscle Myosin II was found to be localized at the <it>Drosophila </it>larval neuromuscular junction; genetics and pharmacology combined with the time-lapse imaging technique FRAP were used to reveal a contribution of Nonmuscle Myosin II to synaptic vesicle movement. FRAP analysis showed that vesicle dynamics were highly dependent on the expression level of Nonmuscle Myosin II.</p> <p>Conclusion</p> <p>Our results provide evidence that Nonmuscle Myosin II is present presynaptically, is important for synaptic vesicle mobility and suggests a role for Nonmuscle Myosin II in shuttling vesicles at the <it>Drosophila </it>neuromuscular junction. This work begins to reveal the process by which synaptic vesicles traverse within the bouton.</p

Heterologous boost with mRNA vaccines against SARS-CoV-2 Delta/Omicron variants following an inactivated whole-virus vaccine.

The coronavirus SARS-CoV-2 has mutated quickly and caused significant global damage. This study characterizes two mRNA vaccines ZSVG-02 (Delta) and ZSVG-02-O (Omicron BA.1), and associating heterologous prime-boost strategy following the prime of a most widely administrated inactivated whole-virus vaccine (BBIBP-CorV). The ZSVG-02-O induces neutralizing antibodies that effectively cross-react with Omicron subvariants. In naïve animals, ZSVG-02 or ZSVG-02-O induce humoral responses skewed to the vaccines targeting strains, but cellular immune responses cross-react to all variants of concern (VOCs) tested. Following heterologous prime-boost regimes, animals present comparable neutralizing antibody levels and superior protection against Delta and Omicron BA.1variants. Single-boost only generated ancestral and omicron dual-responsive antibodies, probably by recall and reshape the prime immunity. New Omicron-specific antibody populations, however, appeared only following the second boost with ZSVG-02-O. Overall, our results support a heterologous boost with ZSVG-02-O, providing the best protection against current VOCs in inactivated virus vaccine-primed populations

Isolation and reversible dimerization of a selenium-selenium three-electron σ-bond

Three-electron σ-bonding that was proposed by Linus Pauling in 1931 has been recognized as important in intermediates encountered in many areas. A number of three-electron bonding systems have been spectroscopically investigated in the gas phase, solution and solid matrix. However, X-ray diffraction studies have only been possible on simple noble gas dimer Xe∴Xe and cyclic framework-constrained N∴N radical cations. Here, we show that a diselena species modified with a naphthalene scaffold can undergo one-electron oxidation using a large and weakly coordinating anion, to afford a room-temperature-stable radical cation containing a Se∴Se three-electron σ-bond. When a small anion is used, a reversible dimerization with phase and marked colour changes is observed: radical cation in solution (blue) but diamagnetic dimer in the solid state (brown). These findings suggest that more examples of three-electron σ-bonds may be stabilized and isolated by using naphthalene scaffolds together with large and weakly coordinating anions

Three dimensional simulation of the arc inside an insulator-arrester with a multichamber system

Based on the thermo-physical properties of plasma air, the temperature and flow fields of an insulator–arrester with a multi-chamber system are investigated using three-dimensional computational fluid dynamics. The plasma flow is assumed to be steady incompressible laminar flow and in local thermodynamic equilibrium. The results obtained show that the arc inside the chamber bends downwards, indicating that the Lorentz force induced is directed away from the exit and pushes plasma air down. The outlet also provides passage for plasma flow both in and out of the chamber