Homogeneous Electrochemical Immunoassay Using an Aggregation-Collision Strategy for Alpha-Fetoprotein Detection.

Homogeneous immunoassays represent an attractive alternative to traditional heterogeneous assays due to their simplicity and high efficiency. Homogeneous electrochemical assays, however, are not commonly accessed due to the requirement of electrode immobilization of the recognition elements. Herein, we demonstrate a new homogeneous electrochemical immunoassay based on the aggregation-collision strategy for the quantification of tumor protein biomarker alpha-fetoprotein (AFP). The detection principle relies on the aggregation of AgNPs induced by the molecular biorecognition between AFP and AgNPs-anti-AFP probes, which leads to an increased AgNP size and decreased AgNP concentration, allowing an accurate self-validated dual-mode immunoassay by performing nanoimpact electrochemistry (NIE) of the oxidation of AgNPs. The intrinsic one-by-one analytical capability of NIE as well as the participation of all of the atoms of the AgNPs in signal transduction greatly elevates the detection sensitivity. Accordingly, the current sensor enables a limit of detection (LOD) of 5 pg/mL for AFP analysis with high specificity and efficiency. More importantly, reliable detection of AFP in diluted human sera of hepatocellular carcinoma (HCC) patients is successfully achieved, indicating that the NIE-based homogeneous immunoassay shows great potential in HCC liquid biopsy.

Mitogenome analysis reveals predominantly ancient Yellow River origin of population inhabiting Datong agro-pastoral ecotone along Great Wall.

The Datong Basin was an important arena for population movement and admixture between the Yellow River Valley and Eastern Steppe. In historical materials, the region was often the setting for a tug-of-war between Han farmers and non-Han nomads. The genetic makeup and population history of this Datong population has, however, remained uncertain. In this study, we analysed 289 mitogenomes from Datong individuals. Our primary findings were: (1) population summary statistics analysis revealed a high level of genetic diversity and strong signals of population expansion in the Datong population; (2) inter-population comparisons (PCA and Fst heatmap) exhibited a close clustering between the Datong population and Northern Han, especially northern frontier groups, such as the Inner Mongolia Han, Heilongjiang Han, Liaoning Han and Tianjin Han; (3) phylogeographic analysis of complete mitogenomes revealed the presence of different components in the maternal gene pools of Datong population-the northern East Asian component was dominant (66.44%), whereas the southern East Asians were the second largest component with 31.49%. We also observed a much reduced west Eurasian (2.07%) component; (4) direct comparisons with ancient groups showed closer relationship between Datong and Yellow River farmers than Eastern Steppe nomads. Despite, therefore, centuries of Eastern Steppe nomadic control over the Datong area, Yellow River farmers had a much more significant impact on the Datong population.

Enantioselective Synthesis of Atropisomers via Vinylidene ortho-Quinone Methides (VQMs).

Atropisomers, arising from conformational restriction, are inherently chiral due to the intersecting dissymmetric planes. Since there are numerous applications of enantiopure atropisomers in catalyst design, drug discovery, and material science, the asymmetric preparation of these highly prized molecules has become a flourishing field in synthetic chemistry. A number of catalysts, synthetic procedures, and novel concepts have been developed for the manufacture of the atropisomeric molecules. However, due to the intrinsic properties of different types of atropisomers featuring biaryl, hetero-biaryl, or non-biaryl architectures, only very few methods pass the rigorous inspection and are considered generally applicable. The development of a broadly applicable synthetic strategy for various atropisomers is a challenge. In this Account, we summarize our recent studies on the enantioselective synthesis of atropisomers using the vinylidene ortho-quinone methides (VQMs) as pluripotent intermediates.The most appealing features of VQMs are the disturbed aromaticity and axial chirality of the allene fragment. At the outset, the applications of VQMs in organic synthesis have been neglected due to their principal liabilities: ephemeral nature, extraordinary reactivity, and multireaction sites. The domestication of this transient intermediate was demonstrated by in situ catalytic asymmetric generation of VQMs, and the reactivity and selectivity were fully explored by judiciously modifying precursors and tuning catalytic systems. A variety of axially chiral heterocycles were achieved through five-, six-, seven- and nine-membered ring formation of VQM intermediates with different kinds of branched nucleophilic functional groups. The axially chiral C-N axis could be constructed from VQM intermediates via N-annulation or desymmetrization of preformed C-N scaffolds. We take advantage of the high electrophilicity of VQMs toward a series of sulfur and carbon based nucleophiles leading to atropisomeric vinyl arenes. Furthermore, chiral helical compounds were realized by cycloaddition or consecutive annulation of VQM intermediates. These achievements demonstrated that the VQMs could work as a nuclear parent for the collective synthesis of distinct and complex optically active atropisomers. Recently, we have realized the isolation and structural characterization of the elusive VQMs, which were questioned as putative intermediates for decades. The successful isolation of VQMs provided direct evidence for their existence and an unprecedented opportunity to directly investigate their reactivity. The good thermal stability and reserved reactivity of the isolated VQMs demonstrated their great potential as synthetic reagents and expanded the border of VQM chemistry.

Organocatalytic Asymmetric Dearomatizing Hetero-Diels-Alder Reaction of Nonactivated Arenes.

Nonactivated arenes, such as benzene derivatives, are chemically inert due to their intrinsic aromaticity and low polarity. The catalytic asymmetric dearomatization (CADA, coined by You and co-workers) of the nonactivated arenes represents a formidable challenge. We herein demonstrated an organocatalytic asymmetric dearomatizing hetero-Diels-Alder reaction of benzene derivatives. The tunable regioselectivity of this strategy allowed delivery of a diversity of stereochemically complex polycyclic compounds and oxahelicenes with excellent stereoselectivity. The high complexity and three-dimensionality of the products are crucial for their potential applications in materials science and drug discovery. Mechanistic studies suggested that this reaction proceeds through a chiral tetra-substituted vinylidene ortho-quinone methide (VQM) intermediate, which is extremely active to overcome the loss of aromaticity of benzene derivatives with concomitant chirality transfer.

Cooperative Asymmetric Cation-Binding Catalysis.

Asymmetric cation-binding catalysis in principle enables the use of (alkali) metal salts, otherwise insoluble in organic solvents, as reagents and effectors in enantioselective reactions. However, this concept has been a formidable challenge due to the difficulties associated with creating a highly organized chiral environment for cations and anions simultaneously. Over the last four decades, various chiral crown ethers have been developed as cation-binding phase-transfer catalysts and examined in asymmetric catalysis. However, the limited ability of chiral crown ethers to generate soluble reactive anions in a confined chiral cage offers a restricted reaction scope and unsatisfactory chirality induction. To address the constraints of monofunctional chiral crown ethers as cation-binding catalysts, it is therefore desirable to develop a cooperative cation-binding catalyst possessing secondary binding sites for anions, which enables the generation of a reactive anion within a chiral cage of a catalyst. This account summarizes our design, development, and applications of chiral BINOL-based oligoethylene glycols (oligoEGs) as a new type of bifunctional cation-binding catalyst. We initially found that achiral oligoEGs were efficient promoters in nucleophilic fluorination with potassium fluoride. Thereby, we hypothesized that, by breaking the closed cyclic ether unit of chiral crown ethers, the free terminal -OH groups could activate the electrophiles by hydrogen bonding whereas the ether oxygens could act as the Lewis base to coordinate metal ions, thus generating soluble anions in a confined chiral cage. This hypothesis was realized by synthesizing a series of chiral variants of oligoEGs by connecting two 3,3'-disubstituted-BINOL units with glycol linkers. Readily available BINOL-based chiral oligoEGs enabled numerous asymmetric transformations out of the reach of chiral monofunctional crown ether catalysts. We have demonstrated that this new type of bifunctional cation-binding catalysts can generate a soluble fluoride anion from alkali metal fluorides, which can be a versatile chiral promoter for diverse asymmetric catalytic reactions, kinetic resolution (selectivity factor of up to ∼2300), asymmetric protonation, Mannich reactions, tandem cyclization reactions, and the isomerization of allylic alcohols and hemithioacetals. We have also successfully utilized our chiral oligoEG catalysts along with alkali metal salts of carbon- and heteroatom-based nucleophiles, respectively, for asymmetric Strecker reactions and the asymmetric synthesis of chiral aminals. The power of our cooperative cation-binding catalysis was exemplified by kinetic resolution reactions of secondary alcohols, achieving highly enantioselective catalysis with only <1 ppm loading of an organocatalyst with high TOFs (up to ∼1300 h-1 at 1 ppm catalyst loading). The broadness and generality of our cooperative asymmetric cation-binding catalysis can be ascribed, in a similar fashion, to active-site architectures of enzymes using allosteric interactions, highly confined chiral cages formed by the incorporation of alkali metal salts in the catalyst polyether chain backbone, and the cooperative activation of reacting partners by hydrogen-bonding and ion-ion interactions. Confining reactive components in such a chiral binding pocket leads to enhanced reactivity and efficient transfer of the stereochemical information.

Detection of small sequence variations within the goat GHR gene and its effects on growth traits.

Growth hormone receptor (GHR) gene is considered to be an important candidate gene in growth traits. Therefore, the purpose of this study was to detect whether there were potential indel variations in the GHR gene that were related to the growth traits of the Shaanbei white cashmere goats (SBWC). In this study, genomic DNA from 931 healthy SBWC individuals were used to verify the relationship between the indel of the GHR gene and growth traits. Two indel variants, P49-bp indel in intron 1 and P1410-bp indel in 3'-UTR, were confirmed. Association analyses demonstrated that these two indel polymorphism loci were associated with the chest circumference and chest width of SBWC. Additionally, for the P49-bp and P1410-bp indel loci, the ID and II genotypes were dominant genotypes, respectively. Moreover, the genotypic distributions of these two indel loci in SBWC were significantly different from those in three other Chinese indigenous goat breeds (HNBG, GZDG and IMWC) (p < 0.05). Taken together, two indel loci (P49-bp indel and P1410-bp indel) both significantly affected the growth traits of goats. This illustrated that these two indel loci might be the potential DNA marker for use in improving the selection and breeding of goats.

Whole-genome sequencing to identify candidate genes for litter size and to uncover the variant function in goats (Capra hircus).

To select candidate genes for goat prolificacy, we managed six multi- and six single-kid female goats at the same feeding level and in the same management mode over a 4-year period. These goats showed stable differences in litter size over five continuous parturition records. Whole-genome re-sequencing was used in all 12 to select candidate genes, namely, AURKA, ENDOG, SOX2, RORA, GJA10, RXFP2, CDC25C, and NANOS3, by the strength of their differentiation signals. Most of the selected genes were enriched in the coiled coil process and ovarian development, which suggests that the coiled coil process has a potential regulatory effect on fecundity. Detection of the distribution of variants and association analyses with litter size in 400 goats showed that NANOS3 exon mutations may lead to a transformation of the protein structure. The variation in CDC25C, ENDOG, and NANOS3 showed a significant association with litter size. These results can contribute to the improvement of reproduction traits in the artificial breeding of goats.

An Isolable Vinylidene ortho-Quinone Methide: Synthesis, Structure and Reactivity.

Commonly, an elusive intermediate is generated from a precursor and then trapped and consumed in a reaction. Vinylidene ortho-quinone methides (VQMs) have been demonstrated as transient axially chiral intermediates in asymmetric catalysis due to their orthogonal π-bonds forming an allene motif. The current understanding of VQMs is primarily based on time-resolved absorption, trapping experiments and computational studies. Herein, we report the first isolation and comprehensive characterization of a VQM, including crystallographic analysis. The disturbed aromaticity of the VQM led to its high reactivity as an electrophile or a 4π-component capable of asymmetric dearomatization of an electron-deficient phenyl group. Notably, the VQM could be isolated in enantiomerically enriched form, and the subsequent transformation was stereospecific, indicating that the generation of the VQM was involved in the enantiodetermining step. This study paves the way for the direct application of VQMs as starting materials.

Atroposelective Construction of Nine-Membered Carbonate-Bridged Biaryls.

We herein demonstrated an efficient method for the atroposelective construction of nine-membered carbonate-bridged biaryls through vinylidene ortho-quinone methide (VQM) intermediates. Diverse products with desirable pharmacological features were synthesized in satisfying yields and good to excellent enantioselectivities. In subsequent bioassays, several agents showed considerable antiproliferative activity via the mitochondrial-related apoptosis mechanism. Further transformations produced more structural diversity and may inspire new ideas for developing functional molecules.

Interaction between the cell walls of microalgal host and fungal carbohydrate-activate enzymes is essential for the pathogenic parasitism process.

Fungi can parasitize microalgae, exerting profound impacts on both the aquatic ecosystems and microalgal mass cultures. In this study, the unicellular green alga Haematococcus pluvialis and the blastocladialean fungus Paraphysoderma sedebokerense were used as a model system to address the mechanisms underlying the fungal parasitism on the algal host. High-throughput metabolic assay indicated that P. sedebokerense can utilize several carbon sources with a preference for mannose, glucose and their oligosaccharides, which was compatible with the profile of the host algal cell walls enriched with glucan and mannan. The results of dual transcriptomics analysis suggested that P. sedebokerense can upregulate a large number of putative carbohydrate-activate enzymes (CAZymes) encoding genes, including those coding for the endo-1,4-ß-glucanase and endo-1,4-ß-mannanase during the infection process. The cell walls of H. pluvialis can be decomposed by both P. sedebokerense and commercial CAZymes (e.g. cellulase and endo-1,4-ß-mannanase) to produce mannooligomers, while several putative parasitism-related genes of P. sedebokerense can be in turn upregulated by mannooligomers. In addition, the parasitism can be blocked by interfering the selected CAZymes including glucanase, mannanase and lysozyme with the specific inhibitors, which provided a framework for screening suitable compounds for pathogen mitigation in algal mass culture.

Hydrogen peroxide plus ascorbic acid enhanced organic matter deconstructions and composting performances via changing microbial communities.

This work aims to investigate the influence of hydrogen peroxide (H2O2) and ascorbic acid (ASCA) on the physicochemical characteristics, organic matter (OM) deconstructions, humification degree and succession of bacterial communities for co-composting of bagasse pith and dairy manure. The results indicated that H2O2 and ASCA accelerated the degradation of lignocellulose, improved the transformation of dissolved organic matter (DOM), and enhanced the content of humic substance (HS) and the degree of its aromatization. The bacterial communities were significantly changed in the presence of additives, in which the relative abundances of Firmicutes and Actinobacteria significantly increased. Redundancy analysis (RDA) indicated that the degradation of OM and lignocellulose more influenced the bacterial community compositions. Conclusively, adding H2O2 and ASCA accelerated lignocellulose degradation efficiency, and improved the composting process, which provided an optimized method to dispose of lignocellulose wastes and livestock manure.

Organocatalytic Enantioselective Construction of Chiral Azepine Skeleton Bearing Multiple-Stereogenic Elements.

Enantioselective construction of molecules bearing multiple stereogenic elements is increasingly related to the synthesis of enantiopure natural products, pharmaceuticals, and functional materials. However, atom-economical and enantioselective approaches to install multiple stereogenic elements in a small molecular template by limited chemical transformation remain challenging. We describe an organocatalytic enantioselective method for the preparation of polychiral molecules bearing four types of stereogenic elements in fused azepines via vinylidene ortho-quinone methide (VQM)-mediated intramolecular electrophilic aromatic substitution. This method was proved robust with a wide range of substrate scope (46-92 % yield), with excellent diastereoselectivity (>20:1 dr) and enantioselectivity achieved (up to 97 % ee). Optical properties and Ru3+ -induced fluorescence responses of these compounds suggest their potential applications in optoelectronic materials and heavy metal ion detection.

Two indel variants of prolactin receptor (PRLR) gene are associated with growth traits in goat.

Prolactin receptor (PRLR) gene plays a crucial role in the milk production, reproduction and the growth of mammals. To fully characterize the structure of the mutation and to further study the function of the goat PRLR gene, two insertion/deletion (indel) loci (12 bp; 16-bp; 5-bp) were detected in 1038 Shaanbei white cashmere (SBWC) goats. Associated analysis revealed that the 16-bp indel mutation was significantly associated the body length, body height, chest depth (CD), body length index (BLI), heart girth index and cannon circumference index (CCI) (p < 0.05). The polymorphism of 5-bp indel was significantly associated with CD, heart girth, CCI and BLI (p < 0.05). Overall, individuals with genotype DD showed better phenotypic traits than individuals with other genotypes at the two loci of PRLR gene in SBWC goat. These findings suggested that the two novel indels within the caprine PRLR gene could be considered as effective DNA molecular markers and could provide a valuable theoretical basis for the application of marker-assisted selection in the goat industry.

A deletion mutation within the ATBF1 gene is strongly associated with goat litter size.

AT motif-binding factor (ATBF1) is a transcription factor that suppresses carcinogenesis and induces neuronal differentiation, as well as it directly interacts with estrogen receptor (ER) and regulates progesterone receptors signaling. Thus ATBF1 gene will possibly greatly affect reproductive tratis in animals. According to our available findings, two indel (insertion/deletion) variants (12-bp indel; 6-bp indel) within the ATBF1 gene were found in Shaanbei White cashmere goats (SWCG). The objective of this work was to investigate their association with litter size in Shaanbei White Cashmere goat. The association analyses uncovered that ATBF1-12bp indel was strongly related to the first-birth litter size in SWCG population (n = 1195, P = 1.0 × 10-3). Individuals with DD genotype (n = 445) had the best litter size when compared with those of ID genotype (n = 420) and DD genotype (n = 330). Besides, Chi-square tests of different litter size individuals showed that multi-kids individuals had higher "D" allelic frequencies and "DD" genotypic frequencies (p < 0.01). These findings suggested the ATBF1-12bp deletion mutation was significantly associated with reproduction-related trait, suggesting that this deletion could be used as an effective molecular marker for litter size in goat breeding.

Kinetic Resolution of Allylic Alcohol with Chiral BINOL-Based Alkoxides: A Combination of Experimental and Theoretical Studies.

The development and characterization of enantioselective catalytic kinetic resolution of allylic alcohols through asymmetric isomerization with chiral BINOL derivatives-based alkoxides as bifunctional Brønsted base catalysts were described in the study. A number of chiral BINOL derivatives-based alkoxides were synthesized, and their structure-enantioselectivity correlation study in asymmetric isomerization identified a promising chiral Brønsted base catalyst, which afforded various chiral secondary allylic alcohols (ee up to 99%, S factor up to >200). In the mechanistic study, alkoxide species were identified as active species and the phenol group of BINOL largely affected the high reactivity and enantioselectivity via hydrogen bonding between the chiral Brønsted base catalyst and substrates. The strategy is the first successful synthesis strategy of various chiral secondary allylic alcohols through enantioselective transition-metal-free base-catalyzed isomerization. The applicability of the strategy had been demonstrated by the synthesis of the bioactive natural product (+)-veraguensin.

Water Adsorption and Transport on Oxidized Two-Dimensional Carbon Materials.

Studies on the adsorption and transport of water molecules with oxidized two-dimensional (2 D) carbon materials have attracted increasing interest owing to their wide range of applications, such as sensing, energy conversion, and membrane separation. In this contribution, the interaction between water molecules and oxidized 2 D carbon materials (i.e., graphene oxide and graphdiyne oxide) is discussed, the influence of water adsorption and transport on the physicochemical properties of 2 D carbon materials is presented, and the recent progress on oxidized 2 D carbon material-based proton conduction, electricity generation, water transport, and humidity sensing is highlighted. The opportunities and challenges in these research fields are discussed, especially the structural stability and chemical modification of 2 D carbon materials.

Optimisation of the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 : single-guide RNA (sgRNA) delivery system in a goat model.

The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system is an efficient method for the production of gene-edited animals. We have successfully generated gene-modified goats and sheep via zygote injection of Cas9 mRNA and single-guide RNA (sgRNA) mixtures. However, the delivery system for microinjection largely refers to methods established for mice; optimised injection conditions are urgently required for the generation of large animals. Here, we designed a study to optimise the Cas9 mRNA and sgRNA delivery system for goats. By comparing four computational tools for sgRNA design and validating the targeting efficiency in goat fibroblasts, we suggest a protocol for the selection of desirable sgRNAs with higher targeting efficiency and negligible off-target mutations. We further evaluated the editing efficiency in goat zygotes injected with Cas9:sgRNA (sg8) and found that injection with 50ngµL-1 Cas9 mRNA and 25ngµL-1 sgRNA yielded an increased editing efficiency. Our results provide a reference protocol for the optimisation of the injection conditions for the efficient editing of large animal genomes via the zygote injection approach.

Enantioselective Control of Both Helical and Axial Stereogenic Elements though an Organocatalytic Approach.

A highly diastereo- and enantio-selective method for the asymmetric synthesis of molecules containing helicenes and stereogenic axes was developed based on organocatalysis. Various compounds bearing both helical and axial stereogenic elements were obtained in excellent enantioselectivities. The mechanism study revealed that the reaction proceeded through two stages: 1) The first cyclization produces a reaction intermediate containing a stereogenic axis. 2) The dynamic kinetic resolution of helix reaction intermediate following with cyclization generates a helix and another stereogenic axis.

Organocatalytic Asymmetric Annulation of ortho-Alkynylanilines: Synthesis of Axially Chiral Naphthyl-C2-indoles.

A chiral Brønsted base catalyzed asymmetric annulation of ortho-alkynylanilines has been developed to access axially chiral naphthyl-C2-indoles via vinylidene ortho-quinone methide (VQM) intermediates. This strategy provides a unique organocatalytic atroposelective route to axially chiral aryl-C2-indole skeletons with excellent enantioselectivity and functional-group tolerance. This transformation was applicable to decagram-scale preparation (50.0 g) with perfect enantioselectivity through simple recrystallization. Moreover, the utility of this reaction was demonstrated by a variety of transformations towards chiral naphthyl-C2-indoles for a series of carbon-heteroatom bond formations. Furthermore, the prepared axially chiral naphthyl-C2-indoles were applied as a chiral skeleton for organocatalytic aza-Baylis-Hillman reaction and asymmetric formal [4+2] tandem cyclization to give the corresponding adducts in high yields with improved enantioselectivity and diastereoselectivity.

Organocatalytic Asymmetric One-Step Desymmetrizing Dearomatization Reaction of Indoles: Development and Bioactivity Evaluation.

An organocatalytic one-step desymmetrizing dearomatization reaction of indoles with in situ formed vinylidene ortho-quinone methides is reported. A set of [6-6-5] and/or [5-6-5] fused indoline heterocycles were obtained in excellent yields with excellent diastereoselectivities (>20:1 d.r.) and enantioselectivities (up to 99 % ee). Moreover, some of the obtained products were screened against a panel of cancer cell lines, and one was identified to inhibit the proliferation of all the tested cancer cells, but showed marginal effects against non-cancerous cells. The methodology provides a platform for the synthesis of new leading compounds with antitumor activity.