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A series of organophosphorus compounds including aryl, alkenyl and alkyl substituted diphenylphosphine oxide derivatives Ph2P(O)R (R = aryl, alkenyl, alkyl), were prepared in high ...yields by using (2-hydroxypropan-2-yl)diphenylphosphine oxide (HDPO) under the similar reaction conditions referring to that with diphenylphosphine oxide (DPO).
A new discrete supramolecular metallacycle functionalized with an alkynylplatinum(II) bzimpy moiety was successfully prepared via coordination-driven self-assembly, and it displayed a reversible ...color change in the solid state between yellow and red, triggered by CH2Cl2 vapor or mechanical grinding. Notably, unlike many known vapochromic systems, the obtained vapochromic metallacycle exhibits ultra-stability, with the red color remaining unchanged in air for several months at room temperature or even under vacuum for >1 week. Further investigation revealed that the chair conformation of the metallacyclic scaffold, which was thought to prevent intermolecular steric repulsion between the alkyl chain and triethylphosphine, favored close molecular stacking through intermolecular Pt···Pt and π–π stacking interactions, thus allowing such vapochromic behavior with ultra-stability.
Animals endemic to deep-sea hydrothermal vents often form obligatory symbioses with bacteria, maintained by intricate host-symbiont interactions. Most genomic studies on holobionts have not ...investigated both sides to similar depths. Here, we report dual symbiosis in the peltospirid snail Gigantopelta aegis with two gammaproteobacterial endosymbionts: a sulfur oxidiser and a methane oxidiser. We assemble high-quality genomes for all three parties, including a chromosome-level host genome. Hologenomic analyses reveal mutualism with nutritional complementarity and metabolic co-dependency, highly versatile in transporting and using chemical energy. Gigantopelta aegis likely remodels its immune system to facilitate dual symbiosis. Comparisons with Chrysomallon squamiferum, a confamilial snail with a single sulfur-oxidising gammaproteobacterial endosymbiont, show that their sulfur-oxidising endosymbionts are phylogenetically distant. This is consistent with previous findings that they evolved endosymbiosis convergently. Notably, the two sulfur-oxidisers share the same capabilities in biosynthesising nutrients lacking in the host genomes, potentially a key criterion in symbiont selection.
A facile and green approach has been developed for synthesis of boron nitride quantum dots (BNQDs). The obtained BNQDs exhibit strong fluorescence and excellent stabilities, including high ...thermostability, good salt tolerance stability, pH-independence ability, and excellent antiphotobleaching capability. The strong inner filter effect between 2,4,6-trinitrophenol (TNP) and BNQDs resulted in fluorescence quenching of BNQDs. Thus, TNP can be selectively and sensitively detected in the concentration range of 0.25–200 μM, with a limit detection of 0.14 μM. The BNQD-based turn-off sensor shows potential prospects for rapidly and selectively detecting TNP in natural water samples without tedious sample pretreatment processes.
•Gives an overview of cold seep systems in the South China Sea.•Outlines seafloor feature, fluid source, biogeochemical process and macroecology.•Evolution of seepage through time and its link to ...hydrate reservoirs is essential.•Integrating in situ observations, remote sensing and modeling at seeps is critical.•Genetic exchange and community similarity between seeps of the SCS is necessary.
Three decades after the discovery of cold seep systems, various sites of hydrocarbon seepage have been found in the South China Sea (SCS). Over the past decade, these sites have become model systems for understanding the variability of hydrocarbon seepage and associated biogeochemical processes. In this review, we describe the cold seep systems of the SCS with an emphasis on seafloor manifestations, fluid sources, biogeochemical processes, and macroecology. Seafloor features associated with seeps include mud volcanoes, pockmarks, and carbonate deposits. A common characteristic of cold seeps is the occurrence of authigenic (i.e., in situ precipitated) carbonate minerals. These carbonates commonly exhibit low δ13C and high δ18O values, suggesting the incorporation of methane-derived carbon and oxygen derived from gas hydrate water. Biogeochemical processes such as sulfate-driven anaerobic oxidation of methane (SD-AOM), the key process at seeps, have been studied in detail with the aim of establishing geochemical proxies to trace these processes into the geological past. We also detail the features characterizing seep ecosystems. Understanding the impact of decomposing methane hydrate on the marine carbon budget remains challenging and requires additional seafloor observations as well as models predicting how gas hydrate responds to changing conditions such as temperature increase, sea level rise, and episodic mass wasting.
A simple and sensitive photoluminescence (PL) assay for the activity of a protein kinase based on the selective aggregation of phosphorylated peptide–graphene quantum dot (GQD) conjugates triggered ...by Zr4+ ion coordination has been established. With more sophisticated design of the peptide substrate sequences, detecting other enzymes could also be possible. Under optimal conditions, a linear relationship between the decreased PL intensity of peptide–GQD conjugates and the concentration of casein kinase II (CK2) in the range from 0.1 to 1.0 unit mL–1 with a detection limit of 0.03 unit mL–1 (3σ) was obtained. The EC50 value (i.e., the enzyme concentration producing 50% substrate conversion) for CK2 was evaluated to be 0.34 unit mL–1. The proposed method showed potential applications in kinase inhibitor screening. To demonstrate the potential of this GQD-based platform for screening of kinase inhibitors in real biological systems, the inhibition of CK2 phosphorylation activity by four different inhibitors (ellagic acid, 5,6-dichlorobenzimidazole-l-β-d-ribofuranoside, emodin, and quercetin) was tested in human serum by comparing signals from samples incubated with the inhibitors against that without any inhibitor. As expected, in the presence of inhibitors, the PL intensity increased with increasing inhibitor efficiency. The IC50 value (inhibitor concentration producing 50% inhibition) for ellagic acid was estimated to be 0.041 μM. The developed protocol provides a new and promising tool for the analysis of both the enzyme and its inhibitors with low cost and excellent performance.
Electrochemiluminescence (ECL), as an advanced sensing process, can selectively control the generation of excited states by changing the potential. However, most of the existing ECL systems rely on ...poisonous coreactants to provide radicals for luminescence; although the ECL efficiency was improved, the athematic coreactants will cause unpredictable interference to the accurate analysis of trace targets. Herein, we realized the ECL of nonemitting molecules by performing intramolecular electron transfer in the olefin-linked covalent organic frameworks (COFs), with a high efficiency of 63.7%. Employing internal dissolved oxygen as the coreactant, it is well suitable for the analysis of various complex samples in the environment. Taking nuclear contamination analysis as the goal orientation, we further illustrated a design of a “turn-on” uranyl ion monitoring system integrating fast response, low detection limit, and high selectivity, showing that new ECL-COFs are promising to facilitate environment-related sensing analysis and structure-feature correlation mechanism exploration.
CpG methylation is one the most predominant epigenetic modification that has been recognized as a molecular-level biomarker for various human diseases. Taking advantage of methylation-dependent ...cleavage and encoding flexibility in nucleic acid functions and structures, we demonstrate the cooperative in situ assembly of G-quadruplex DNAzyme nanowires for one-step sensing of CpG methylation in human genomes. This nanodevice displays good specificity and high sensitivity with a limit of detection (LOD) of 0.565 aM in vitro and 1 cell in vivo. It can distinguish 0.001% CpG methylation level from excess unmethylated DNA, quantify different CpG methylation targets from diverse human cancer cells, and even discriminate CpG methylation expressions between lung tumor and precancerous tissues. Importantly, this nanodevice can be performed isothermally in one step within 2 h in a label-free manner without any bisulfite conversion, fluorescence tagging, and PCR amplification process, providing a new platform for genomic methylation-related clinical diagnosis and biomedical research.
Using a method optimized in hepatocellular carcinoma (HCC), we established patient‐derived xenograft (PDX) models with an increased take rate (42.2%) and demonstrated that FBS +10% dimethyl sulfoxide ...exhibited the highest tumor take rate efficacy. Among 254 HCC patients, 103 stably transplantable xenograft lines that could be serially passaged, cryopreserved and revived were established. These lines maintained the diversity of HCC and the essential features of the original specimens at the histological, transcriptome, proteomic and genomic levels. Tumor engraftment was associated with lack of encapsulation, poor tumor differentiation, large size and overexpression of cancer stem cell biomarkers, and was an independent predictor for overall survival and tumor recurrence after resection. To confirm the preclinical value of the PDX model in HCC treatment, several antitumor agents were tested in 16 selected PDX models. The results revealed a high degree of pharmacologic heterogeneity in the cohort, as well as heterogeneity to different agents in the same individual. The sorafenib responses observed between HCC patients and the corresponding PDXs were also consistent. After molecular characterization of the PDX models, we explored the predictive markers for sorafenib response and found that mitogen‐activated protein kinase kinase kinase 1 (MAP3K1) might play an important role in sorafenib resistance and sorafenib response is impaired in patients with MAP3K1 downexpression. Our results indicated that PDX models could accurately reproduce patient tumors biology and could aid in the discovery of new treatments to advance in precision medicine.
What's new?
Patient‐derived xenografts (PDX) models offer a promising preclinical tool. Here, the authors established the largest bank of hepatocellular carcinoma (HCC) PDX models with a high and stable tumor take rate that recapitulated the key clinical and molecular characteristics of primary tumors. The tumor take rate was associated with expression of cancer stem cell proteins, lack of tumor encapsulation, poor differentiation, advanced stage, overall survival, and time to recurrence in patients. The models were used to identify MAP3K1 expression as an indicator of patient response to sorafenib treatment. PDX models are valuable surrogates for HCC patients and could facilitate translational research.
Water is found able to determine the selectivity of Brønsted acid-catalyzed C-O cleavage reactions of trialkyl phosphites: with water, the reaction quickly takes place at room temperature to afford ...quantitative yields of H-phosphonates; without water, the reaction selectively affords alkylphosphonates in high yields, providing a novel halide-free alternative to the famous Michaelis-Arbuzov reaction. This method is general as it can be readily extended to phosphonites and phosphinites and a large scale reaction with much lower loading of the catalyst, enabling a simple, efficient, and practical preparation of the corresponding organophosphorus compounds. Experimental findings in control reactions and substrate extension as well as preliminary theoretical calculation of the possible transition states all suggest that the monomolecular mechanism is preferred.
Water is unexpectedly found to determine a TfOH-catalyzed C-O cleavage reaction of trialkyl phosphites to produce H-phosphonates or alkylphosphonates selectively.
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