Plasmalogen-rich foods promote the formation of cubic membranes in amoeba Chaos under stress conditions.

Previous studies have indicated that the ability to form cubic membrane (CM), a three-dimensional periodic structure with cubic symmetry, in amoeba (Chaos carolinense) under stress conditions depends on the type of food organism supplied before cell starvation. The significant increase in docosapentaenoic acid (DPA; C22:5n-6) during the starvation period has been reported to induce CM formation and support Chaos cell survival. In this article, we further investigated the lipid profiles of food organisms of the Chaos cells to reveal the key lipid components that might promote CM formation. Our results show that the lipids extracted from cells of the native food organism Paramecium multimicronucleatum are enriched in plasmalogens. More specifically, plasmalogen phosphatidylcholine and plasmalogen phosphatidylethanolamine might be the key lipids that trigger CM formation in Chaos cells under starvation stress conditions. Unexpectedly, CM formation in these cells is not supported when the native food organism was replaced with plasmalogen-deficit Tetrahymena pyriformis cells. Based on a previous lipidomics study on amoeba Chaos and this study on the lipid composition of its food organisms, three key lipids (plasmalogen phosphatidylcholine, plasmalogen phosphatidylethanolamine and diacyl-phosphatidylinositol) were identified and used for liposomal construction. Our in vitro study revealed the potential role of these lipids in a nonlamellar phase transition. The negative staining transmission electron microscopy data of our liposomal constructs support the notion that plasmalogens may curve the membrane, which, in turn, may facilitate membrane fusion and vesicular formation, which is crucial for membrane dynamics and trafficking.

A novel ratiometric and colorimetric chemosensor for highly sensitive, selective and ultrafast tracing of HClO in live cells, bacteria and zebrafish.

Hypochlorous acid (HClO) along with its ionic form, hypochlorite anion (ClO-) are critical reactive oxygen species (ROS), which play vital roles in biological systems. Dysregulated production of HClO/ClO- can result in tissue damage and cause a variety of diseases. Besides, Sodium hypochlorite has been widely used as a bleaching agent for water disinfection, surface cleaning in daily life. Excessive exposure to sodium hypochlorite will lead to symptoms of severe breathing and skin problems. Therefore, developing a state-of-the-art (simple, highly sensitive, highly selective and super fast-response) sensor for tracking HClO is of biological, toxicological, and environmental importance. Though many HClO probes have been reported so far, this big aim still presents a challenge. Researchers around the world are continuing to develop new HClO probes that could improve their sensitivity, selectivity, the limit of detection, response time, easiness to use, etc. Herein, with coumarin as the fluorophore molecule, we rationally developed a novel chemosensor (CMTH) for detecting HClO with both ratiometric and colorimetric responses resulted from the oxidation reaction of CN bond. Further analysis results indicated that CMTH can realize highly sensitive with low limit of detection (256 nM, among the best of its kind) and highly selective (over a bunch of interfering analytes) imaging detection of HClO in multiple organisms with low cytotoxicity, and good cell and tissue permeability as well. In particular, compared to other fluorescent HClO probes reported so far, CMTH excels in the response time to HClO (< 40 s), being the top-notch of its kind. Besides, owing to its excellent water solubility, CMTH can also be applied to track HClO in the environmental system. Taken together, we have presented here a novel chemosensor, CMTH, as a colorimetric and ratiometric chemosensor for highly sensitive and ultrafast imaging detection of HClO in aqueous solutions, eukaryotic cells, prokaryotic bacteria and vertebrate zebrafish.

The Potential Role of Bioactive Plasmalogens in Lung Surfactant.

Neonatal respiratory distress syndrome (NRDS) is a type of newborn disorder caused by the deficiency or late appearance of lung surfactant, a mixture of lipids and proteins. Studies have shown that lung surfactant replacement therapy could effectively reduce the morbidity and mortality of NRDS, and the therapeutic effect of animal-derived surfactant preparation, although with its limitations, performs much better than that of protein-free synthetic ones. Plasmalogens are a type of ether phospholipids present in multiple human tissues, including lung and lung surfactant. Plasmalogens are known to promote and stabilize non-lamellar hexagonal phase structure in addition to their significant antioxidant property. Nevertheless, they are nearly ignored and underappreciated in the lung surfactant-related research. This report will focus on plasmalogens, a minor yet potentially vital component of lung surfactant, and also discuss their biophysical properties and functions as anti-oxidation, structural modification, and surface tension reduction at the alveolar surface. At the end, we boldly propose a novel synthetic protein-free lung surfactant preparation with plasmalogen modification as an alternative strategy for surfactant replacement therapy.