Water Flow inside Polamide Reverse Osmosis Membranes: A Non-Equilibrium Molecular Dynamics Study

Water flow inside polyamide (PA) reverse osmosis (RO) membranes is studied by steady state nonequilibrium molecular dynamics (NEMD) simulations in this work. The PA RO membrane is constructed with the all-atom model, and the density and average pore size obtained thereby are consistent with the latest experimental results. To obtain the time-independent water flux, a steady state NEMD method is used under various pressure drops. The water flux in our simulations, which is calculated under higher pressure drops, is in a linear relation with the pressure drops. Hence, the water flux in lower pressure drops can be reliably estimated, which could be compared with the experimental results. The molecular details of water flowing inside the membrane are considered. The radial distribution function and residence time of water around various groups of polyamide are introduced to analyze the water velocities around these groups, and we find that water molecules flow faster around benzene rings than around carboxyl or amino groups in the membrane, which implies that the main resistance of mass transport of water molecules comes from the carboxyl or amino groups inside the membranes. This finding is in good consistency with experimental results and suggests that less free carboxyl or amino groups should be generated inside RO membranes to enhance water permeance

Discovery of Novel Polycyclic Phloroglucinols via an Improved One-Pot Method

In nature, polycyclic phloroglucinols are a class of compounds with considerable structural diversity and promising biological activities. Herein, we present an improved one-pot method that replaces the solution reaction conditions by mixing the reactants with column chromatography silica gel. Through this convenient, mild, slow, and diversity-oriented strategy, eight structurally unique polycyclic phloroglucinols were discovered, of which compound 1 possesses a rare cage-like skeleton. All compounds determined their structures by X-ray diffraction. Compared with traditional methods, this synthetic strategy produced better diversity and unique structures under milder conditions, suggesting that this method has great potential in lead compound discovery. The optimal reaction conditions were determined by high-performance liquid chromatography (HPLC) monitoring over time. In addition, density functional theory (DFT) calculations were performed to investigate the possible generative pathway of compound 1. We also examined the neuroprotective actions of selected compounds on SH-SY5Y cells and the MPP+-induced Caenorhabditis elegans PD model

Divergent roles of BECN1 in LC3 lipidation and autophagosomal function

<div><p>BECN1/Beclin 1 is regarded as a critical component in the class III phosphatidylinositol 3-kinase (PtdIns3K) complex to trigger autophagy in mammalian cells. Despite its significant role in a number of cellular and physiological processes, the exact function of BECN1 in autophagy remains controversial. Here we created a <i>BECN1</i> knockout human cell line using the TALEN technique. Surprisingly, the complete loss of BECN1 had little effect on LC3 (MAP1LC3B/LC3B) lipidation, and LC3B puncta resembling autophagosomes by fluorescence microscopy were still evident albeit significantly smaller than those in the wild-type cells. Electron microscopy (EM) analysis revealed that BECN1 deficiency led to malformed autophagosome-like structures containing multiple layers of membranes under amino acid starvation. We further confirmed that the PtdIns3K complex activity and autophagy flux were disrupted in <i>BECN1</i>^−/− cells. Our results demonstrate the essential role of BECN1 in the functional formation of autophagosomes, but not in LC3B lipidation.</p></div

Exploiting the Transcriptome of Euphrates Poplar, <i>Populus euphratica</i> (Salicaceae) to Develop and Characterize New EST-SSR Markers and Construct an EST-SSR Database

<div><p>Background</p><p>Microsatellite markers or Simple Sequence Repeats (SSRs) are the most popular markers in population/conservation genetics. However, the development of novel microsatellite markers has been impeded by high costs, a lack of available sequence data and technical difficulties. New species-specific microsatellite markers were required to investigate the evolutionary history of the Euphratica tree, Populus euphratica, the only tree species found in the desert regions of Western China and adjacent Central Asian countries.</p><p>Methodology/Principal Findings</p><p>A total of 94,090 non-redundant Expressed Sequence Tags (ESTs) from P. euphratica comprising around 63 Mb of sequence data were searched for SSRs. 4,202 SSRs were found in 3,839 ESTs, with 311 ESTs containing multiple SSRs. The most common motif types were trinucleotides (37%) and hexanucleotides (33%) repeats. We developed primer pairs for all of the identified EST-SSRs (eSSRs) and selected 673 of these pairs at random for further validation. 575 pairs (85%) gave successful amplification, of which, 464 (80.7%) were polymorphic in six to 24 individuals from natural populations across Northern China. We also tested the transferability of the polymorphic eSSRs to nine other Populus species. In addition, to facilitate the use of these new eSSR markers by other researchers, we mapped them onto Populus trichocarpa scaffolds in silico and compiled our data into a web-based database (<a href="http://202.205.131.253:8080/poplar/resources/static_page/index.html" target="_blank">http://202.205.131.253:8080/poplar/resources/static_page/index.html</a>).</p><p>Conclusions</p><p>The large set of validated eSSRs identified in this work will have many potential applications in studies on P. euphratica and other poplar species, in fields such as population genetics, comparative genomics, linkage mapping, QTL, and marker-assisted breeding. Their use will be facilitated by their incorporation into a user-friendly web-based database.</p></div

Discovery of Novel Polycyclic Phloroglucinols via an Improved One-Pot Method

In nature, polycyclic phloroglucinols are a class of compounds with considerable structural diversity and promising biological activities. Herein, we present an improved one-pot method that replaces the solution reaction conditions by mixing the reactants with column chromatography silica gel. Through this convenient, mild, slow, and diversity-oriented strategy, eight structurally unique polycyclic phloroglucinols were discovered, of which compound 1 possesses a rare cage-like skeleton. All compounds determined their structures by X-ray diffraction. Compared with traditional methods, this synthetic strategy produced better diversity and unique structures under milder conditions, suggesting that this method has great potential in lead compound discovery. The optimal reaction conditions were determined by high-performance liquid chromatography (HPLC) monitoring over time. In addition, density functional theory (DFT) calculations were performed to investigate the possible generative pathway of compound 1. We also examined the neuroprotective actions of selected compounds on SH-SY5Y cells and the MPP+-induced Caenorhabditis elegans PD model

Hypoglycaemic and hypolipidemic activities of total flavonoids from <i>Nymphaea candida</i> flowers on diabetic mice

This study aimed to investigate the hypoglycaemic and hypolipidemic activities of total flavonoids from Nymphaea candida (NCTF). The result showed that NCTF could significantly ameliorate various indicators such as FBG, OGTT, TC, TG, LDL-C, and HDL-C in ALX-induced diabetic mice compared with the model group. Meanwhile, in the therapeutical effect study of NCTF on high-fat and high-sugar diets combined with STZ-induced T2DM mice, all parameters including RBG, INS, and INSR related to diabetes were significantly improved by NCTF as well as the serum ALT, AST, ALP, CR, MDA, and IL-6 activities. NCTF could significantly increase the expression levels of SOD and PPAR-γ in T2DM. Pathological observation showed that NCTF could improve the damage to pancreatic and liver tissues in T2DM mice. In conclusion, NCTF has better hypoglycaemic and hypolipidemic effects, and its mechanism may be related to its antioxidant, PPAR-γ regulation, and inhibiting inflammatory cytokine expression.</p

Phenotypes of wild-type (WT), <i>cry1</i>-mutant, <i>PeCRY1</i>-transgenic <i>cry1</i>-mutant, and <i>PeCRY1</i>-transgenic WT plants.

<p>(A) <i>PeCRY1</i> transcript levels in WT, <i>cry1</i> mutant, and transgenic lines. m-1, m-2, and m-3, three <i>cry1</i> mutant lines transformed with <i>PeCRY1</i>; W-1, W-2, and W-3, three WT lines transformed with <i>PeCRY1</i>. (B) Phenotypes of WT, <i>cry1</i>-mutant, and the two transgenic lines (m-1 and W-2) grown under dark, white, blue, and red light. Scale bar represents 1 cm. (C) and (D) Hypocotyl and primary root lengths of WT, <i>cry1</i>-mutant, and the two transgenic lines grown under dark, white, blue, and red light. (E) Anthocyanin content of WT, <i>cry</i>1-mutant, and the two transgenic lines grown under blue light.</p

PeCRY1 protein sequence analysis.

<p>(A) Structural domains of the PeCRY1 protein. Analysis of protein sequences in the National Center for Biotechnology Information (NCBI) database was performed using the CD-search software. (B) Amino acid sequence alignment of cryptochrome proteins from <i>Arabidopsis</i>, winter rape, apple, tomato, European aspen, and Euphrates poplar. The alignment was constructed using DNAman version 5.2.2 software. Identical residues are highlighted by black boxes. Red lines under the sequences indicate the TGYP, WRWK, and LLDAD motifs. Black lines above the sequences indicate the DQMVP-E/D-STAESS (DAS) domain located in the C-terminal region. Residues that interact with FAD and MTHF are indicated by black rectangles and black dots, respectively. A nuclear localization signal (NLS) predicted using NLStradamus software is indicated by red stars. (C) DAS domain sequence logos. The sequence alignment of the domains was generated using ClustalX, and conserved motif logos were created using the WebLogo program (<a href="http://weblogo.threeplusone.com/" target="_blank">http://weblogo.threeplusone.com/</a>).</p

Divergent roles of BECN1 in LC3 lipidation and autophagosomal function

<div><p>BECN1/Beclin 1 is regarded as a critical component in the class III phosphatidylinositol 3-kinase (PtdIns3K) complex to trigger autophagy in mammalian cells. Despite its significant role in a number of cellular and physiological processes, the exact function of BECN1 in autophagy remains controversial. Here we created a <i>BECN1</i> knockout human cell line using the TALEN technique. Surprisingly, the complete loss of BECN1 had little effect on LC3 (MAP1LC3B/LC3B) lipidation, and LC3B puncta resembling autophagosomes by fluorescence microscopy were still evident albeit significantly smaller than those in the wild-type cells. Electron microscopy (EM) analysis revealed that BECN1 deficiency led to malformed autophagosome-like structures containing multiple layers of membranes under amino acid starvation. We further confirmed that the PtdIns3K complex activity and autophagy flux were disrupted in <i>BECN1</i>^−/− cells. Our results demonstrate the essential role of BECN1 in the functional formation of autophagosomes, but not in LC3B lipidation.</p></div

Bioluminescence Assisted Switching and Fluorescence Imaging (BASFI)

Förster resonance energy transfer (FRET) and bioluminescence resonance energy transfer (BRET) are two major biophysical techniques for studying nanometer-scale motion dynamics within living cells. Both techniques read photoemission from the transient RET-excited acceptor, which makes RET and detection processes inseparable. We here report a novel hybrid strategy, bioluminescence assisted switching and fluorescence imaging (BASFI) using a bioluminescent <i>Renilla</i> luciferase RLuc8 as the donor and a photochromic fluorescent protein Dronpa as the acceptor. When in close proximity, RET from RLuc8 switches Dronpa from its original dark state to a stable bright state, whose fluorescence is imaged subsequently with an external laser. Such decoupling between RET and imaging processes in BASFI promises high photon flux as in FRET and minimal bleedthroughs as in BRET. We demonstrated BASFI with Dronpa-RLuc8 fusion constructs and drug-inducible intermolecular FKBP-FRB protein–protein interactions in live cells with high sensitivity, resolution, and specificity. Integrating the advantages of FRET and BRET, BASFI will be a valuable tool for various biophysical studies