Enantioselective Synthesis of Atropisomeric Tri-Axis Naphthalenes via Diels-Alder Reaction and Dehydrative Aromatization of Isobenzofurans.

Atropisomers with multiple stereogenic axes have attracted much attention due to their increasing significance in the fields of natural products, chiral materials, and drug discoveries. However, the catalytic stereoselective construction of axially chiral ring scaffolds with more than two axes on a single benzene ring remains a challenging task. Herein, we present an efficient method for synthesizing triaxially chiral polysubstituted naphthalene scaffolds via sequential Ni(II)-catalyzed Diels-Alder reaction of isobenzofurans and TfOH-promoted dehydrative aromatization reaction.

Constructing artificial gap junctions to mediate intercellular signal and mass transport.

Natural gap junctions are a type of channel protein responsible for intercellular signalling and mass communication. However, the scope of applications for these proteins is limited as they cannot be prepared at a large scale and are unable to spontaneously insert into cell membranes in vitro. The construction of artificial gap junctions may provide an alternative strategy for preparing analogues of the natural proteins and bottom-up building blocks necessary for the synthesis of artificial cells.

Enantioselective Synthesis of Inherently Chiral Calix[4]arenes via Palladium-Catalyzed Asymmetric Intramolecular C-H Arylations.

We report herein an efficient approach for the enantioselective synthesis of inherently chiral calix[4]arenes via palladium-catalyzed asymmetric intramolecular C-H arylations. Using a chiral bifunctional phosphine-carboxylate ligand, the inherent chirality on macrocyclic scaffolds was induced successfully, from which a wide range of calix[4]arenes with fluorenone motifs were obtained with good yields and excellent enantioselectivities (up to >99% ee). The synthetic utility of this method was demonstrated by diverse transformations of the products, thus substantially expanding the chemical space of chiral calix[4]arenes.

Methylene-bridge tryptophan fatty acylation regulates PI3K-AKT signaling and glucose uptake.

Protein fatty acylation regulates numerous cell signaling pathways. Polyunsaturated fatty acids (PUFAs) exert a plethora of physiological effects, including cell signaling regulation, with underlying mechanisms to be fully understood. Herein, we report that docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) regulate PI3K-AKT signaling by modifying PDK1 and AKT2.

Adsorption-Based Detoxification of Endotoxins by Porous Flexible Organic Frameworks.

Bacterial lipopolysaccharides (LPS, endotoxins) cause sepsis that is responsible for a huge amount of mortality globally. However, their neutralization or detoxification remains an unmet medical need. We envisaged that cationic organic frameworks with persistent hydrophobic porosity may adsorb and thus neutralize LPS through a combination of cooperative ion-pairing electrostatic attraction and hydrophobicity.

Charged Tubular Supramolecule Boosting Multivalent Interactions for the Drastic Suppression of Aβ Fibrillation.

Anti-Aβ therapy has dominated clinical trials for the prevention and treatment of Alzheimer's disease (AD). However, suppressing Aβ aggregation and disintegrating mature fibrils simultaneously remains a great challenge. In this work, we developed a new strategy using a charged tubular supramolecule (CTS) with pillar[5]arene as the backbone and modifying amino and carboxyl groups at the tubular terminals (noted as CTS-A, CTS-A/C, and CTS-C, respectively) to suppress Aβ fibrillation for the first time.

Voltage-Driven Flipping of Zwitterionic Artificial Channels in Lipid Bilayers to Rectify Ion Transport.

We developed a voltage-sensitive artificial transmembrane channel by mimicking the dipolar structure of natural alamethicin channel. The artificial channel featured a zwitterionic structure and could undergo voltage-driven flipping in the lipid bilayers. Importantly, this flipping of the channel could lead to their directional alignment in the bilayers and rectifying behavior for ion transport.

Nuclear dihydroxyacetone phosphate signals nutrient sufficiency and cell cycle phase to global histone acetylation.

Global histone acetylation varies with changes in the nutrient and cell cycle phases; however, the mechanisms connecting these variations are not fully understood. Herein, we report that nutrient-related and cell-cycle-regulated nuclear acetate regulates global histone acetylation. Histone deacetylation-generated acetate accumulates in the nucleus and induces histone hyperacetylation.

Gramicidin A-based unimolecular channel: cancer cell-targeting behavior and ion transport-induced apoptosis.

A series of glycoside-peptide conjugates were prepared by engineering at the N-terminus of the natural peptide gramicidin A. The conjugate containing galactose moiety formed a unimolecular transmembrane channel and mediated ion transport to induce apoptosis of cancer cells. More importantly, it exhibited liver cancer cell-targeting behavior due to the galactose-asialoglycoprotein receptor recognition.

Unimolecular artificial transmembrane channels showing reversible ligand-gating behavior.

A series of peptide-appended bisresorcinarenes were synthesized, which adopted tubular conformation induced by intramolecular hydrogen bonds. The derivatives formed unimolecular artificial transmembrane channels in lipid bilayers to enable selective transport of monovalent cations. Importantly, the channels exhibited reversible ligand-gating behavior in response to alkyl amine and Cu2+.

Artificial Aquaporin That Restores Wound Healing of Impaired Cells.

Artificial aquaporins are synthetic molecules that mimic the structure and function of natural aquaporins (AQPs) in cell membranes. The development of artificial aquaporins would provide an alternative strategy for treatment of AQP-related diseases. In this report, an artificial aquaporin has been constructed from an amino-terminated tubular molecule, which operates in a unimolecular mechanism.

Author Correction: Artificial water channels enable fast and selective water permeation through water-wire networks.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Artificial water channels enable fast and selective water permeation through water-wire networks.

Artificial water channels are synthetic molecules that aim to mimic the structural and functional features of biological water channels (aquaporins). Here we report on a cluster-forming organic nanoarchitecture, peptide-appended hybrid[4]arene (PAH[4]), as a new class of artificial water channels. Fluorescence experiments and simulations demonstrated that PAH[4]s can form, through lateral diffusion, clusters in lipid membranes that provide synergistic membrane-spanning paths for a rapid and selective water permeation through water-wire networks.

Targeting the Cell Membrane by Charge-Reversal Amphiphilic Pillar[5]arene for the Selective Killing of Cancer Cells.

A charge-reversal amphiphilic pillar[5]arene, P5NH-DCA, bearing 10 charge-reversal headgroups is reported. It targets the cell membrane of cancer cells and selectively destroys the cancer cells by disrupting the membrane. In the acidic tumor microenvironment, the headgroup charge of P5NH-DCA reversed from negative to positive owing to hydrolysis of the acid-labile amide group.

A synthetic channel that efficiently inserts into mammalian cell membranes and destroys cancer cells.

Despite the fact that a large number of synthetic channels have been developed in the last three decades, few of them can function in mammalian cell membranes because of their weak membrane insertion abilities. This study describes a tubular molecule with terminal positively charged amino groups that displays a strong ability to insert into lipid bilayers composed of phosphatidylcholine and consequently forming unimolecular transmembrane channels. It has been demonstrated that the insertion of the channel into the phosphatidylcholine bilayers was driven by the electrostatic interaction between the positively charged amino groups of the channel molecules and the negatively charged phosphate groups of the lipid molecules.

Supramolecular Kandinsky circles with high antibacterial activity.

Nested concentric structures widely exist in nature and designed systems with circles, polygons, polyhedra, and spheres sharing the same center or axis. It still remains challenging to construct discrete nested architecture at (supra)molecular level. Herein, three generations (G2-G4) of giant nested supramolecules, or Kandinsky circles, have been designed and assembled with molecular weight 17,964, 27,713 and 38,352 Da, respectively.

Reversible photo-gated transmembrane channel assembled from an acylhydrazone-containing crown ether triad.

We have prepared a crown ether triad containing acylhydrazone units. In solution, the triad can self-assemble linearly to form an organogel. UV light-induced E/Z isomerization of the C[double bond, length as m-dash]N bond of the acylhydrazone unit endows the assembly with photo-sensitivity.

Synthetic Channel Specifically Inserts into the Lipid Bilayer of Gram-Positive Bacteria but not that of Mammalian Erythrocytes.

A series of tubular molecules with different lengths have been synthesized by attaching Trp-incorporated peptides to the pillar[5]arene backbone. The tubular molecules are able to insert into the lipid bilayer to form unimolecular transmembrane channels. One of the channels has been revealed to specifically insert into the bilayer of the Gram-positive bacteria.

Directional Potassium Transport through a Unimolecular Peptide Channel.

Three unimolecular peptide channels have been designed and prepared by using the β-helical conformation of gramicidin A (gA). The new peptides bear one to three NH groups at the N-end and one to three CO groups at the C-end. These zwitterionic peptides were inserted into lipid bilayers in an orientation-selective manner.

[Diet composition and seasonal variation in feeding habits of Collichthy lucidus in Yangtze Estuary, China].

Spiny head croaker (Collichthy lucidus) is an important bottom fish distributing from the East China Sea to the Yellow Sea. In order to investigate the seasonal variation in diet composition and feeding habits, a total of 270 specimens were collected in the Yangtze Estuary from November, 2013 to August, 2014, and analyzed by using the stomach contents analysis method. The importance of different prey items was evaluated by the frequency of occurrence, abundance and mass followed by using these data to calculate the index of relative importance (IRI) and the index of preponderance (Ip) for each taxonomic category.

[Assessment of resource situation of Collichthys lucidus in coastal waters of the Yangtze estuary].

In order to assess the resource status of Collichthys lucidus in coastal waters of Yangtze estuary, the growth and population parameters were studied by the length frequency distribution method based on the bottom trawl investigation data from 2012 to 2013. Von Bertalanffy growth parameters were calculated by using the ELEFAN module in FiSAT II software while the natural mortality rate (M) was estimated via Pauly's empirical equation. Besides, the Beverton-Holt dynamic model was developed to predict the variation trend of C.

Highly permeable artificial water channels that can self-assemble into two-dimensional arrays.

Bioinspired artificial water channels aim to combine the high permeability and selectivity of biological aquaporin (AQP) water channels with chemical stability. Here, we carefully characterized a class of artificial water channels, peptide-appended pillar[5]arenes (PAPs). The average single-channel osmotic water permeability for PAPs is 1.