Cranial suture lineage and contributions to repair of the mouse skull.

The cranial sutures are proposed to be a stem cell niche, harbouring skeletal stem cells that are directly involved in development, homeostasis and healing. Like the craniofacial bones, the sutures are formed from both mesoderm and neural crest. During cranial bone repair, neural crest cells have been proposed to be key players; however, neural crest contributions to adult sutures are not well defined, and the relative importance of suture proximity is unclear. Here, we use genetic approaches to re-examine the neural crest-mesoderm boundaries in the adult mouse skull. These are combined with calvarial wounding experiments suggesting that suture proximity improves the efficiency of cranial repair. Furthermore, we demonstrate that Gli1+ and Axin2+ skeletal stem cells are present in all calvarial sutures examined. We propose that the position of the defect determines the availability of neural crest-derived progenitors, which appear to be a key element in the repair of calvarial defects.

A Fluorescent Unnatural Mannosamine Derivative with Enhanced Emission Upon Complexation with Cucurbit[7]uril.

Metabolic incorporation of unnatural functionality on glycans has allowed chemical biologists to observe and affect cellular processes. Recent work has resulted in glycan-fluorophore structures that allow for direct visualization of glycan-mediated processes, shining light on their role in living systems. This work describes the serendipitous discovery of a small chemical reporter-fluorophore. Investigations into the mechanism of fluorescence arising from (trimethylsilyl)methylglycine appended on mannosamine suggest rigidity and restriction of lone pair geometry contribute to the fluorescent behaviour. In fact, in situ cyclization and encapsulation in cucurbit[7]uril enhance fluorescence to levels that can be observed in live cells. While the reported unnatural mannosamine does not traverse the sialic acid biosynthetic pathway, this discovery may lead to small, "turn-on" chemical reporters for incorporation in living systems.

Shortwave Infrared Fluorofluorophores for Multicolor In Vivo Imaging.

Developing chemical tools to detect and influence biological processes is a cornerstone of chemical biology. Here we combine two tools which rely on orthogonality- perfluorocarbons and multiplexed shortwave infrared (SWIR) fluorescence imaging- to visualize nanoemulsions in real time in living mice. Drawing inspiration from fluorous and SWIR fluorophore development, we prepared two SWIR-emissive, fluorous-soluble chromenylium polymethine dyes. These are the most red-shifted fluorous fluorophores- "fluorofluorophores"-to date. After characterizing the dyes, their utility was demonstrated by tracking perfluorocarbon nanoemulsion biodistribution in vivo. Using an excitation-multiplexed approach to image two variables simultaneously, we gained insight into the importance of size and surfactant identity on biodistribution.

[Combination characteristics of frankincense and myrrh and progress and prospect of their combination efficacy and mechanism].

Herbal pair is formed based on the experience summary of doctors' deep understanding and perception of the medicinal nature in long-term clinical practice. It gradually becomes the exquisite structural unit for preparing traditional Chinese medicine(TCM) prescriptions, and often plays a core bridge role in the prescription combination. Frankincense and myrrh are raw resin materials of incense abroad, which are subsequently included as Chinese medicinal herbs and endowed with rich medicinal connotation. With the functions of relaxing Zang-fu organs, activating blood and relieving pain, they have definite clinical efficacy. From the perspective of herbal description and clinical application, this study systematically analyzed the combination of frankincense and myrrh as well as their combination proportion, efficacy characterization, diseases and syndromes, effective components and action mechanism. On this basis, the focus of in-depth research of frankincense-myrrh and the application prospects were proposed, in order to further reveal the potential meditation law of this herbal pair, thus contributing to clinical practice and drug innovation of traditional Chinese medicine, and providing reference for understanding of TCM medicinal nature and research of herbal pairs.

A microtubule-localizing activity-based sensing fluorescent probe for imaging hydrogen peroxide in living cells.

Hydrogen peroxide (H2O2) is a major reactive oxygen species (ROS) in living systems with broad roles spanning both oxidative stress and redox signaling. Indeed, owing to its potent redox activity, regulating local sites of H2O2 generation and trafficking is critical to determining downstream physiological and/or pathological consequences. We now report the design, synthesis, and biological evaluation of Microtubule Peroxy Yellow 1 (MT-PY1), an activity-based sensing fluorescent probe bearing a microtubule-targeting moiety for detection of H2O2 in living cells. MT-PY1 utilizes a boronate trigger to show a selective and robust turn-on response to H2O2 in aqueous solution and in living cells. Live-cell microscopy experiments establish that the probe co-localizes with microtubules and retains its localization after responding to changes in levels of H2O2, including detection of endogenous H2O2 fluxes produced upon growth factor stimulation. This work adds to the arsenal of activity-based sensing probes for biological analytes that enable selective molecular imaging with subcellular resolution.

[Mechanism of Olibanum-Myrrha in treatment of rheumatoid arthritis based on network pharmacology and molecular docking].

In this paper, network pharmacology method and molecular docking technique were used to investigate the target genes of Olibanum and Myrrha compatibility and the possible mechanism of action in the treatment of rheumatoid arthritis(RA). Our team obtained the main active components of Olibanum-Myrrha based on literatures study, relevant traditional Chinese medicine systematic pharmacological databases and literature retrieval, and made target prediction of the active components through SwissTargetPrediction database. At the same time, RA-related targets were collected through DrugBank, GeneCards and Therapeutic Target Database(TDD) databases; and VENNY 2.1 was use to collect intersection targets to map common targets of drug and disease of Venn diagram online. The team used STRING database to construct PPI protein interaction network diagram, and screen out core targets according to the size of the interaction, and Cytoscape 3.6.0 software was used to construct network models of "traditional Chinese medicine-component-target" "traditional Chinese medicine-component-target-disease" and core target interaction network model. The intersection target was analyzed by using DAVID 6.8 online database for GO function analysis and KEGG pathway enrichment analysis, and Pathon was used to visualization. AutoDock Vina and Pymol were used to connect the core active components with the core targets. Sixteen active components of Olibanum-Myrrha pairs were found and collected in the laboratory, and 320 relevant potential targets, 468 RA-related targets and 62 intersection targets were obtained through the Venn diagram. It mainly acted on multiple targets, such as IL6, TNF, IL1 B and MAPK1, involving TNF signaling pathway and Toll-like receptor signaling pathway in RA treatment. Finally, in this study, possible targets and signaling pathways of Olibanum-Myrrha compatibility therapy for RA were discussed, and molecular docking between core targets and core active components was conducted, which could provide scientific basis for the study on the mechanism of Olibanum-Myrrha compatibility.

[Ant i-inflammatory mechanism of active components in Olibanum and Myrrha based on network pharmacology and cell experiments].

Two terpenes, 3-keto-tirucalla-8,24-dien-21-oic acid(KTDA) and 2-methoxy-5-acetoxy-furanogermacr-1(10)-en-6-one(FSA), are isolated from Olibanum and Myrrha respectively, which are characterized by high yield and easy crystallization during the preparation. The present study explored the regulatory targets and anti-inflammatory mechanism of KTDA and FSA based on network pharmacology and cell viability assay. First, the drug-likeness of KTDA and FSA was predicted by Swiss ADME. The target prediction of active components was carried out by Swiss Target Prediction and Pharmmapper. TTD, Drug Bank, and Gene Cards were searched for inflammation-related target genes of KTDA and FSA. Protein-protein interaction(PPI) analysis was performed on the inflammatory targets of KTDA and FSA by STRING, and Cytoscape was used to conduct topological analysis of the interaction results and construct the PPI network. GO function and KEGG pathway enrichment analyses of inflammatory targets of KTDA and FSA were carried out by DAVID, and a " component-target-pathway" network was constructed. Finally, lipopolysaccharide(LPS)-induced RAW264. 7 cells were treated with KTDA and FSA at different concentrations, and nitric oxide(NO) concentration and protein and m RNA expression levels were detected. The results showed that both KTDA and FSA showed good drug-likeness. A total of 157 and 142 inflammation-related targets of KTDA and FSA were screened out. PPI network analysis showed that MAPK1, AKT1, MAPK8, PIK3 CA,PIK3 R1, EGFR, etc. might be the key proteins for the anti-inflammatory effect. PI3 K/AKT and MAPK signaling pathways were obtained by KEGG and GO-BP enrichment. Cell experiment results showed that KTDA and FSA could exert anti-inflammatory effects by inhibiting NO production, reducing the phosphorylation levels of JNK, p38, and AKT proteins, and down-regulating the m RNA expression of interleukin(IL)-1ß and IL-6. Meanwhile, FSA could also inhibit ERK phosphorylation. The results indicated that KTDA and FSA had significant anti-inflammatory activity, which provided a scientific basis and important support for the further research,development, and utilization of Olibanum and Myrrha.

Copper regulates rest-activity cycles through the locus coeruleus-norepinephrine system.

The unusually high demand for metals in the brain, along with insufficient understanding of how their dysregulation contributes to neurological diseases, motivates the study of how inorganic chemistry influences neural circuitry. We now report that the transition metal copper is essential for regulating rest-activity cycles and arousal. Copper imaging and gene expression analysis in zebrafish identifies the locus coeruleus-norepinephrine (LC-NE) system, a vertebrate-specific neuromodulatory circuit critical for regulating sleep, arousal, attention, memory and emotion, as a copper-enriched unit with high levels of copper transporters CTR1 and ATP7A and the copper enzyme dopamine ß-hydroxylase (DBH) that produces NE. Copper deficiency induced by genetic disruption of ATP7A, which loads copper into DBH, lowers NE levels and hinders LC function as manifested by disruption in rest-activity modulation. Moreover, LC dysfunction caused by copper deficiency from ATP7A disruption can be rescued by restoring synaptic levels of NE, establishing a molecular CTR1-ATP7A-DBH-NE axis for copper-dependent LC function.

Amidation, Esterification, and Thioesterification of a Carboxyl-Functionalized Covalent Organic Framework.

Three new post-synthetic modification reactions, namely amidation, esterification, and thioesterification, were demonstrated on a novel highly crystalline two-dimensional covalent organic framework (COF), COF-616, bearing pre-installed carboxyl groups. The strategy can be used to introduce a large variety of functional groups into COFs and the modifications can be carried out under mild reaction conditions, with high yields, and an easy work-up protocol. As a proof of concept, various chelating functionalities were successfully incorporated into COF-616 to yield a family of adsorbents for efficient removal of several contaminants in the water.

Bioinspired Thiophosphorodichloridate Reagents for Chemoselective Histidine Bioconjugation.

Site-selective bioconjugation to native protein residues is a powerful tool for protein functionalization, with cysteine and lysine side chains being the most common points for attachment owing to their high nucleophilicity. We now report a strategy for histidine modification using thiophosphorodichloridate reagents that mimic post-translational histidine phosphorylation, enabling fast and selective labeling of protein histidines under mild conditions where various payloads can be introduced via copper-assisted alkyne-azide cycloaddition (CuAAC) chemistry. We establish that these reagents are particularly effective at covalent modification of His-tags, which are common motifs to facilitate protein purification, as illustrated by selective attachment of polyarginine cargoes to enhance the uptake of proteins into living cells. This work provides a starting point for probing and enhancing protein function using histidine-directed chemistry.

A Physical Organic Approach to Tuning Reagents for Selective and Stable Methionine Bioconjugation.

We report a data-driven, physical organic approach to the development of new methionine-selective bioconjugation reagents with tunable adduct stabilities. Statistical modeling of structural features described by intrinsic physical organic parameters was applied to the development of a predictive model and to gain insight into features driving the stability of adducts formed from the chemoselective coupling of oxaziridine and methionine thioether partners through Redox Activated Chemical Tagging (ReACT). From these analyses, a correlation between sulfimide stabilities and sulfimide ν (C═O) stretching frequencies was revealed. We exploited the rational gains in adduct stability exposed by this analysis to achieve the design and synthesis of a bis-oxaziridine reagent for peptide stapling. Indeed, we observed that a macrocyclic peptide formed by ReACT stapling at methionine exhibited improved uptake into live cells compared to an unstapled congener, highlighting the potential utility of this unique chemical tool for thioether modification. This work provides a template for the broader use of data-driven approaches to bioconjugation chemistry and other chemical biology applications.

Inorganic Chemistry Approaches to Activity-Based Sensing: From Metal Sensors to Bioorthogonal Metal Chemistry.

The complex network of chemical processes that sustain life motivates the development of new synthetic tools to decipher biological mechanisms of action at a molecular level. In this context, fluorescent and related optical probes have emerged as useful chemical reagents for monitoring small-molecule and metal signals in biological systems, enabling visualization of dynamic cellular events with spatial and temporal resolution. In particular, metals occupy a central role in this field as analytes in their own right, while also being leveraged for their unique biocompatible reactivity with small-molecule substrates. This Viewpoint highlights the use of inorganic chemistry principles to develop activity-based sensing platforms mediated by metal reactivity, spanning indicators for metal detection to metal-based reagents for bioorthogonal tracking, and manipulation of small and large biomolecules, illustrating the privileged roles of metals at the interface of chemistry and biology.

Dicyanovinyl substituted push-pull chromophores: effects of central C[double bond, length as m-dash]C/phenyl spacers, crystal structures and application in hydrazine sensing.

To discern the distinctive effect of the C[double bond, length as m-dash]C bond and the phenyl bridge on the photophysical and chemical properties of D-π-A molecular systems, three new dicyanovinyl substituted push-pull chromophores 1-3 containing either a C[double bond, length as m-dash]C bond or a phenyl ring as the central π-linker were synthesized by the Suzuki-Miyaura and Knoevenagel reactions. Together with the counterpart of 1 developed by Zhang's group (TPE-z), their optical properties and single crystal structures were systematically and comparatively investigated. Notably, the simple π-extension of a C[double bond, length as m-dash]C linker to a phenyl ring between electron donor and electron acceptor moieties could greatly affect the photophysical properties of chromophores, particularly leading to significant hypsochromic shifts in both absorption and emission spectra. Meanwhile, as a node of twisted sections in chromophores, the C[double bond, length as m-dash]C bond was demonstrated to play an important role in the nonradiative relaxation of excited states, as compared to the rigid phenyl spacer. Moreover, the three chromophores were found to display spectral responses to hydrazine with slightly different sensitivities, and visual detection of hydrazine in the gaseous state was achieved via using readily fabricated paper test strips.

Charge carrier recombination dynamics in a bi-cationic perovskite solar cell.

The compositional engineering is of great importance to tune the electrical and optical properties of perovskite and improve the photovoltaic performance of perovskite solar cells. The exploration of the corresponding photoelectric conversion processes, especially the carrier recombination dynamics, will contribute to the optimization of the devices. In this work, perovskite with mixed methylammonium (MA) and formamidinium (FA) as organic cations, MA0.4FA0.6PbI3, is fabricated to study the influence of the bi-cation on the charge carrier recombination dynamics. X-ray diffraction analysis indicates the existence of the MAPbI3-FAPbI3 phase segregation in the bi-cationic perovskite crystal. The time-resolved photoluminescence dynamics presents a relatively fast carrier recombination process ascribed to the charge transfer from MAPbI3 to FAPbI3 in the bi-cationic perovskite film. The carrier recombination dynamics investigated by transient photovoltage measurements reveals a biphasic trap-assisted carrier recombination mechanism in the bi-cationic device, which involves carrier recombination in the MAPbI3 phase and FAPbI3 phase, respectively. The ultimate presentation of the carrier recombination process is closely related to the charge transfer between the two perovskite phases.

The Intestinal Copper Exporter CUA-1 Is Required for Systemic Copper Homeostasis in Caenorhabditis elegans.

Copper plays key catalytic and regulatory roles in biochemical processes essential for normal growth, development, and health. Defects in copper metabolism cause Menkes and Wilson's disease, myeloneuropathy, and cardiovascular disease and are associated with other pathophysiological states. Consequently, it is critical to understand the mechanisms by which organisms control the acquisition, distribution, and utilization of copper. The intestinal enterocyte is a key regulatory point for copper absorption into the body; however, the mechanisms by which intestinal cells transport copper to maintain organismal copper homeostasis are poorly understood. Here, we identify a mechanism by which organismal copper homeostasis is maintained by intestinal copper exporter trafficking that is coordinated with extraintestinal copper levels in Caenorhabditis elegans Specifically, we show that CUA-1, the C. elegans homolog of ATP7A/B, localizes to lysosome-like organelles (gut granules) in the intestine under copper overload conditions for copper detoxification, whereas copper deficiency results in a redistribution of CUA-1 to basolateral membranes for copper efflux to peripheral tissues. Worms defective in gut granule biogenesis exhibit defects in copper sequestration and increased susceptibility to toxic copper levels. Interestingly, however, a splice isoform CUA-1.2 that lacks a portion of the N-terminal domain is targeted constitutively to the basolateral membrane irrespective of dietary copper concentration. Our studies establish that CUA-1 is a key intestinal copper exporter and that its trafficking is regulated to maintain systemic copper homeostasis. C. elegans could therefore be exploited as a whole-animal model system to study regulation of intra- and intercellular copper trafficking pathways.

A Modular Ionophore Platform for Liver-Directed Copper Supplementation in Cells and Animals.

Copper deficiency is implicated in a variety of genetic, neurological, cardiovascular, and metabolic diseases. Current approaches for addressing copper deficiency rely on generic copper supplementation, which can potentially lead to detrimental off-target metal accumulation in unwanted tissues and subsequently trigger oxidative stress and damage cascades. Here we present a new modular platform for delivering metal ions in a tissue-specific manner and demonstrate liver-targeted copper supplementation as a proof of concept of this strategy. Specifically, we designed and synthesized an N-acetylgalactosamine-functionalized ionophore, Gal-Cu(gtsm), to serve as a copper-carrying "Trojan Horse" that targets liver-localized asialoglycoprotein receptors (ASGPRs) and releases copper only after being taken up by cells, where the reducing intracellular environment triggers copper release from the ionophore. We utilized a combination of bioluminescence imaging and inductively coupled plasma mass spectrometry assays to establish ASGPR-dependent copper accumulation with this reagent in both liver cell culture and mouse models with minimal toxicity. The modular nature of our synthetic approach presages that this platform can be expanded to deliver a broader range of metals to specific cells, tissues, and organs in a more directed manner to treat metal deficiency in disease.

Copper regulates cyclic-AMP-dependent lipolysis.

Cell signaling relies extensively on dynamic pools of redox-inactive metal ions such as sodium, potassium, calcium and zinc, but their redox-active transition metal counterparts such as copper and iron have been studied primarily as static enzyme cofactors. Here we report that copper is an endogenous regulator of lipolysis, the breakdown of fat, which is an essential process in maintaining body weight and energy stores. Using a mouse model of genetic copper misregulation, in combination with pharmacological alterations in copper status and imaging studies in a 3T3-L1 white adipocyte model, we found that copper regulates lipolysis at the level of the second messenger, cyclic AMP (cAMP), by altering the activity of the cAMP-degrading phosphodiesterase PDE3B. Biochemical studies of the copper-PDE3B interaction establish copper-dependent inhibition of enzyme activity and identify a key conserved cysteine residue in a PDE3-specific loop that is essential for the observed copper-dependent lipolytic phenotype.

Characterization of the influences of morphology on the intrinsic properties of perovskite films by temperature-dependent and time-resolved spectroscopies.

Organic-inorganic halide perovskites have attracted enormous attention owing to their promising application in photovoltaic devices. The morphology of the perovskites is the key to driving the performance of perovskite devices, which necessitates a systematic study. In this work, two typical morphologies, i.e., flake and cube, of perovskite films are fabricated, and the temperature-dependent optical absorption and photoluminescence properties of the two types of perovskite film are systematically investigated. From the temperature-dependent spectra, both exciton and phase transition temperatures of the flake film are found to be about 10 K lower than those of the cube one. Meanwhile, the influences of the morphology on the exciton binding energy, optical phonon energy and polaron binding energy are quantitatively characterized. The exciton binding of the flake film is nearly three times smaller than that of the cube one, while the phonon coupling energy and the polaron binding energy of the former are about 5 meV and 2 meV larger than those of the latter. Furthermore, the results of photoluminescence lifetime and charge separation efficiency further reveal that the charge carrier kinetics in the two kinds of perovskite films is significantly different. The current study provides a theoretical framework to understand the fundamental physics of perovskites and to promote the design and enhancement of active materials for improved optoelectronic devices.

Diels-Alder reaction-triggered bioorthogonal protein decaging in living cells.

Small molecules that specifically activate an intracellular protein of interest are highly desirable. A generally applicable strategy, however, remains elusive. Herein we describe a small molecule-triggered bioorthogonal protein decaging technique that relies on the inverse electron-demand Diels-Alder reaction for eliminating a chemically caged protein side chain within living cells. This method permits the efficient activation of a given protein (for example, an enzyme) in its native cellular context within minutes.

Analysis of Thermal Field Distribution in Winter over Beijing from 1985 to 2015 Using Landsat Thermal Data.

Heat supply, automobile exhaust, industrial production and decrease of thermal inertia in winter caused by the decrease of vegetation coverage leads to an obvious difference in the distribution of the land thermal field in the winter compared with other seasons. The Urban thermal field distribution in the winter directly affects the spread of air pollutants, which has important implications for analyzing the contribution of the thermal field to particulate air pollution. Atmospheric transmissivity and atmospheric upwelling/downwelling radiance in simulations are first calculated using the moderate spectral resolution atmospheric transmittance algorithm and computer model (MODTRAN). Then, we solve the radiative transfer model of the thermal infrared band by constructing a look-up table. In addition, the accuracy estimation is performed using the simulated data, showing that when the error range of emissivity and water vapor content are confined to ±0.005 and ±0.6, respectively, the temperature retrieval error are less than 0.348 and 2.117 K, respectively indicating the high retrieval accuracy of the method. In addition, the long-term sequenced Landsat TM and ETM+ data were selected to retrieve land surface temperature (LST) during 1985-2015. The analysis of the temporal and spatial distribution of thermal fields in Beijing show that the spatial and temporal variations are observable. The spatial variation covers four levels: high temperature is distributed within the second ring, low temperature loops are distributed between the second and the fifth ring, high temperature is distributed in the outer suburb areas and the lowest temperature is distributed in the western mountainous areas. Meanwhile, the temporal variation of thermal field distribution changed a great deal during the rapid development in the past 3 decades: the low temperature loop expanded from the third to the sixth ring; the intensity and scope of the heat island effect within the second ring increased gradually.