Exclusive Recognition Research Articles

Civilization Approach in Economic Researches

The proposed article presents the author’s view on how the civilizational approach to the analysis of economic processes developed and what it consisted of in various predominantly Russian-language literary sources of the 19th century. The author recognizes that the volume of sources containing evidence of such an approach is immense, so he focuses on those that he considers the most important and indicative for assessing the contribution of Russian science to the development of such a methodology of economic analysis, as well as the modern concept of human economy, to which some of the author’s earlier works were devoted. In the author’s opinion, the civilization approach already at the early stages of economic research helped to bring out non-material, cultural-psychological and moral aspects of economic behavior and formation of economic institutions. Most studies of the impact of civilizational development on the economy demonstrate a certain one-directionality, that is, they are built in the logic of a hierarchical world order: civilized nations are at the top of the pyramid of development, and uncivilized, barbaric nations are located somewhere at its base. The civilizational approach allows us to abandon the “economism”, which has become a template, based on the exclusive recognition of the primacy of material factors of social development. In addition, in the author’s opinion, there is an opportunity to raise the question of the correctness of the multipolarity concept, which can no longer describe in detail the formation of a new world order. The civilizational approach gives a chance to assess the processes of globalization and fragmentation in a new way, not as antagonistic processes, but as mutually conditioned. In general, the future development of a multi-civilizational world order and its conflict-free nature will be largely determined by the willingness of representatives of primarily Western civilization to recognize the need to gradually abandon the paradigm of universality of social development conditions in favor of manners identity paradigm, uniqueness of economic structure and behavior, and the importance of identity for economic development.

Self-Healing B ← N-Based Hydrogen-Bonded Organic Framework for Exclusive Recognition and Separation of Toluene from Methyl-Cyclohexane.

The effective separation of aromatic and aliphatic hydrocarbons remains a notable challenge in the petrochemical industry. Herein, we report a self-healing three-dimensional B ← N-based hydrogen-bonded organic framework (HOF), BN-HOF-1, constructed from discrete B ← N inclusive dimers through weak C-H···F and C-H···N hydrogen-bonding interactions. To make use of the specific recognition of the B ← N inclusive dimers for the toluene molecules and the reversible ad/desorption nature of this novel HOF, BN-HOF-1 can exclusively recognize and separate toluene from the mixtures of toluene-methylcyclohexane, thus generating 99.6% pure toluene from its mixtures after gentle heating, the recorded value among any reported materials for toluene purification. After the toluene molecules were released from the framework, it becomes the condensed BN-HOF-1a, which can be further reused for the highly selective recognition and purification of toluene from its binary mixtures, through the reversible structural recovery back to BN-HOF-1. Single-crystal X-ray diffraction and molecular modeling studies reveal that the high specific toluene recognition is attributed to the complementary electrostatic potential between the host B ← N inclusive dimers and the guest toluene, while the self-healing and recovery nature of this HOF is attributed to weak intermolecular hydrogen-bonding interactions.

Exclusive ion recognition using host-guest sandwich complexes.

Ion recognition in porous aqueous media utilizing polyethers involves the formation of 1 : 1 and higher-order host-guest complexes. The effectiveness of these interactions relies on the optimal size of the host cavity to encapsulate the guest ions. While liquid/liquid extraction based on host-guest interactions offers higher specificity in metal ion extraction, it results in the co-extraction of unwanted coordinating solvents and counter-anions. Therefore, an improved protocol is required by which the ion can be selectively trapped within the host cavity and simultaneously decrease the guest coordination with the outside environment. This study delves into the microscopic mechanisms underpinning the exclusive ion recognition through the formation of 2 : 1 host-guest sandwich complexes, which reduce metal coordination with solvent or counter-ions, ensuring selectivity. Our analysis shows that ions with a radius larger than the host cavity, such as cesium (Cs+), form stable host-guest sandwich complexes at elevated host concentrations. In this study, we performed molecular dynamics simulations to investigate the microscopic details of Cs+ interactions with open-chain and preorganized polyethers, namely podand, crown, and cryptand in electrolyte media. Our findings reveal that the formation of stable Cs+-crown sandwich complexes significantly reduces Cs+ coordination with H2O and NO3-. This loss of solute coordination leads to exclusivity in bound metal ions, offering a potential strategy for efficient solvent extraction.

A B←N framework based on 1D dative B←N polymers for exclusive recognition and separation of benzene from its azeotrope

A B←N framework based on 1D dative B←N polymers for exclusive recognition and separation of benzene from its azeotrope

Wheat Pore-Forming Toxin-Like Protein Confers Broad-Spectrum Resistance to Fungal Pathogens in Arabidopsis.

Fusarium head blight (FHB), caused by the hemibiotrophic fungus Fusarium graminearum, is one of the major threats to global wheat productivity. A wheat pore-forming toxin-like (PFT) protein was previously reported to underlie Fhb1, the most widely used quantitative trait locus in FHB breeding programs worldwide. In the present work, wheat PFT was ectopically expressed in the model dicot plant Arabidopsis. Heterologous expression of wheat PFT in Arabidopsis provided a broad-spectrum quantitative resistance to fungal pathogens including F. graminearum, Colletotrichum higginsianum, Sclerotinia sclerotiorum, and Botrytis cinerea. However, there was no resistance to bacterial or oomycete pathogens Pseudomonas syringae and Phytophthora capsici, respectively in the transgenic Arabidopsis plants. To explore the reason for the resistance response to, exclusively, the fungal pathogens, purified PFT protein was hybridized to a glycan microarray having 300 different types of carbohydrate monomers and oligomers. It was found that PFT specifically hybridized with chitin monomer, N-acetyl glucosamine (GlcNAc), which is present in fungal cell walls but not in bacteria or oomycete species. This exclusive recognition of chitin may be responsible for the specificity of PFT-mediated resistance to fungal pathogens. Transfer of the atypical quantitative resistance of wheat PFT to a dicot system highlights its potential utility in designing broad-spectrum resistance in diverse host plants. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Exclusive Recognition of CO2 from Hydrocarbons by Aluminum Formate with Hydrogen-Confined Pore Cavities.

Exclusive capture of carbon dioxide (CO2) from hydrocarbons via adsorptive separation is an important technology in the petrochemical industry, especially for acetylene (C2H2) production. However, the physicochemical similarities between CO2 and C2H2 hamper the development of CO2-preferential sorbents, and CO2 is mainly discerned via C recognition with low efficiency. Here, we report that the ultramicroporous material Al(HCOO)3, ALF, can exclusively capture CO2 from hydrocarbon mixtures, including those containing C2H2 and CH4. ALF shows a remarkable CO2 capacity of 86.2 cm3 g-1 and record-high CO2/C2H2 and CO2/CH4 uptake ratios. The inverse CO2/C2H2 separation and exclusive CO2 capture performance from hydrocarbons are validated via adsorption isotherms and dynamic breakthrough experiments. Notably, the hydrogen-confined pore cavities with appropriate dimensional size provide an ideal pore chemistry to specifically match CO2 via a hydrogen bonding mechanism, with all hydrocarbons rejected. This molecular recognition mechanism is unveiled by in situ Fourier-transform infrared spectroscopy, X-ray diffraction studies, and molecular simulations.

THE ISLAMIC LEGAL SYSTEM IN MALAYSIA: CHALLENGES AND STRATEGIES

It is established that Islam has played a crucial role in the development of Tanah Melayu as evidenced by its progression from a small village to a bustling trade hub in the Nusantara, and ultimately to a fully-fledged nation. Being an all-encompassing religion, Islam came not only as a belief system; it has as well brought positive changes and order in the political, economic and social aspects of Tanah Melayu. In the legal aspect, though Islamic law was used to adjudicate civil and criminal matters at first, the coming of the colonists suppressed its usage and the Common Law was instead, enforced. However, approaching the independence of Tanah Melayu, efforts of the Muslim intellects and reformists have managed to secure the position of Islam in the Federal Constitution. Today, though Islamic law is ensured with exclusive jurisdiction and recognition, its institutions strive to stay pertinent. Coordinating the law at the federal level remains a challenge especially that involving the inheriten power of states over Islam and its law. By using the qualitative method of research methodology, the paper analyses primary and secondary data descriptively by looking into the legal history and development of Islamic law until today. It is found that although Islam and its law are sourced from the supreme law in the country, it has to constantly overcome its challenges to remain relevant and significant. Thus, the paper seeks to look into challenges in administering Islamic law and its institutions. It also suggests some practical strategies toward a standardised and exclusive Islamic legal system in Malaysia.

The CONCP in Southern Africa and the OAU’s Liberation Committee: Settling Internal Disputes for the Independence of Angola and Mozambique

An important but surprisingly neglected player in the history of the struggle for independence in the African Portuguese colonies is the Conferência das Organizações Nacionalistas das Colónias Portuguesas (CONCP), an umbrella organisation uniting the Partido Africano da Independência da Guiné e Cabo Verde (PAIGC), for Guinea Bissau, the Movimento Popular de Libertação de Angola (MPLA), for Angola, the Frente de Libertação de Moçambique (Frelimo), for Mozambique and the Movimento de Libertação de São Tomé e Príncipe (MLSTP), for São Tomé e Príncipe. Founded in Casablanca in 1961, the CONCP was not a participant in military action, but it strengthened the movements’ ideological cohesion and international diplomacy. Its most controversial goals were perhaps the settlement of internal divisions among the nationalists of Angola and Mozambique and the endorsement of the MPLA and Frelimo as the sole legitimate liberation movements in their countries. To this end, it also established a strategic relationship with specific nationalist movements in southern Africa opposing the white minority regimes and with the Organisation of African Unity (OAU) Liberation Committee. After its second conference, held in Dar es Salaam in 1965, the CONCP intensified its pressures to secure the MPLA and Frelimo exclusive recognition and support by the OAU, but it was successful only in the second case.

Fluorescent nonwoven fabric with synergistic dual fluorescence emission for visible and selective ammonia gas detection

Although ammonia gas plays an important role in the modern society, it poses a serious threat to human beings. Therefore, an effective ammonia gas-detection method with features like convenient operation, rapid response, excellent selectivity, and high sensitivity is urgently needed. Herein, a fluorescent polyethylene/polypropylene nonwoven fabric with co-existing pyrene units and –SO3H groups was fabricated by radiation-induced graft polymerization (RIGP), followed by a two-step chemical modification. The prepared fluorescent nonwoven fabric displays a rare dual emission and has a related high quantum yield of 32.65%. Besides, a remarkable synergistic interaction between the pyrene units and –SO3H groups causes the prepared fluorescent nonwoven fabric to exhibit superior ammonia detection abilities. Pyrene units act as efficient luminescence centers and therefore significantly enhance the sensitivity of ammonia detection. The –SO3H groups act as exclusive recognition centers and improve the selectivity for ammonia. Interestingly, the changes in the fluorescence intensity of the dual emission display a reverse trend upon interaction with the ammonia gas, causing the fluorescence color to change from purple to blue, thus achieving the visible detection of ammonia gas. Additionally, the as-prepared fluorescent nonwoven fabric can detect ammonia with the advantages of rapid response (in 5 s), excellent selectivity, high sensitivity, low detection limit (approximately 0.6 ppm), and good reproducibility and reusability.

A Novel Molecularly Imprinted Electrochemical Sensor Based on PANI@GO for Highly Sensitive and Selective Analysis of Trace Epigoitrin

Identification and quantification of epigoitrin (EP) in some herbs and traditional Chinese medicine (TCM) preparations are critical to pharmacokinetic study and pharmaceutical quality control due to its distinct antiviral activity. So, developing highly sensitive and selective method for detection of EP is essential for clinical treatment and drug development. In this study, a novel molecularly imprinted electrochemical sensor for detection of EP was firstly constructed. With acrylamide imprinting systems, surface imprinting on the polyaniline functionalized graphene oxide was employed to prepare molecularly imprinted polymer by electro-polymerization, which follow-up constructed afford specific binding cavities, endowing the exclusive recognition ability. Furthermore, the polyacrylamide chain is anchored to the polyaniline chain by covalent bonds, which is beneficial for raising electrochemistry signal. Under the optimized condition, the sensor demonstrates a linear wide range of 4.6 × 10−7 mol l−1 ∼ 4.6 × 10−5 mol l−1 with a correlation coefficient of 0.9953 and a low LOD of 8.21 × 10−8 mol l−1 (S/N = 3). Additionally, the sensor showed good stability, repeatability (RSD 1.52%) and selectivity. The method was applied to analyze EP in the extraction from Isatidis Radix with a recovery higher than 97.8% and RSD less than 1.81%. This work provided a novel strategy for on-site, real-time and rapid detection of indicator components from TCM.

β-Cyclodextrin and graphene oxide co-strengthened AgRu bimetal mesoporous nanozyme: An efficient strategy for visual detection and removal of toxic Hg2+ and Cl−

In this work, to efficiently eliminate the threat of toxic Cl− and Hg2+, a kind of AgRu bimetal mesoporous nanozyme co-stabilized by β-cyclodextrin and graphene oxide (AgRu@β-CD-co-GO) was first developed by a homogeneous redox and assembly method. The mesoporous microstructure and a large number of hydroxyl groups and GO aryl rings endowed AgRu@ β-CD-co-GO with superior peroxidase-mimic performance and enough active spots to adsorb more toxic Cl− and Hg2+. Under optimal conditions (pH 4.0, 350 μL 1.5 mM TMB and 200 μL 1.0 M H2O2 and incubated for 30 min at 25 °C), AgRu@ β-CD-co-GO could accelerate the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) into blue oxTMB in the presence of H2O2. Toxic Cl− or Hg2+ would exclusively alter its peroxidase-like activity, accompanied with the characteristic UV–vis absorption intensity at 653 nm (A653) decreased and color changed from blue to colorless. AgRu@ β-CD-co-GO was successfully applied for visual detection of Cl− and Hg2+ and enriched removal of them after their detection. The detection limits were low to be 3.2 × 10−10 mol∙L−1 for Hg2+ and 6.4 × 10−8 mol/L for Cl−. After detection, more than 94.9% Hg2+ and 93.8% Cl− could be removed by only a simple filtration. The mechanisms for peroxidase-mimic activity of AgRu@ β-CD-co-GO and its exclusive recognition of Hg2+ and Cl− were proposed.

An Adaptive Hydrogen-Bonded Organic Framework for the Exclusive Recognition of p-Xylene.

Separation of xylene isomers is one of the most important but most challenging and energy-intensive separation processes in the petrochemical industry. Here, we report an adaptive hydrogen-bonded organic framework (HOF-29) constructed from a porphyrin based organic building block 4,4',4'',4'''-(porphyrin-5,10,15,20-tetrayl) tetrabenzonitrile (PTTBN), exhibiting the exclusive molecular recognition of p-xylene (pX) over its isomers of o-xylene (oX) and m-xylene (mX), as clearly demonstrated in the single crystal structure transformation and 1 H NMR studies. Single crystal structure studies show that single-crystal-to-single-crystal transformation from the as-synthesized HOF-29 to the pX exclusively included HOF-29⊃pX is triggered by the encapsulation of pX molecules, accompanied by sliding of the 2D layers and local distortion of the ligand, which provides multiple C-H⋅⋅⋅π interactions.

Priming third-party social exclusion does not elicit children's inclusion of out-group members.

This study investigates how culture and priming 3- to 7-year-old children (N = 186) with third-party social exclusion affects their subsequent inclusion of out-group members. Children in societies that tend to value social independence (Germany, New Zealand) and interdependence (Northern Cyprus) were randomly assigned to minimal groups. Next, they watched video stimuli depicting third-party social exclusion (exclusion condition) or neutral content (control condition). We assessed children's recognition of the social exclusion expressed in the priming videos and their understanding of the emotional consequences thereof. We furthermore assessed children's inclusion behaviour in a ball-tossing game in which participants could include an out-group agent into an in-group interplay. Children across societies detected third-party social exclusion and ascribed lower mood to excluded than non-excluded protagonists. Children from Germany and New Zealand were more likely to include the out-group agent into the in-group interaction than children from Northern Cyprus. Children's social inclusion remained unaffected by their exposure to third-party social exclusion primes. These results suggest that children from diverse societies recognize social exclusion and correctly forecast its negative emotional consequences, but raise doubt on the notion that social exclusion exposure affects subsequent social inclusion.

Queering the Queer

Due to the systemic reality of heteropatriarchy, queer bodies often struggle to find a place of belonging within the African context in general and faith spaces in particular. Even though there has been a shift towards a more inclusive theological discourse within the African Christian faith landscape, the bodies of African Izitabane are still predominantly viewed as a Western import and a threat to African culture and its traditions. Because of this, queer bodies continue to find themselves within hostile environments. This has contributed to queer people moving towards alternative spaces of worship and the development of the queer church in which all bodies are welcomed. Although queer bodies have created these alternative faith spaces to move away from the systems of heteropatriarchy that force them to conform to heteronormative standards within the church, a study conducted in KwaZulu-Natal, South Africa, found that queer people often recreate these systems in their own spaces. The pervasive systemic nature of heteropatriarchy finds expression in the insistence on masculine bodies being placed in positions of authority and the exclusive recognition of relationships that conform to heteronormative standards. In the process of trying to escape the confines of a male centred heteropatriarchal African church, we argue that queer people have not succeeded in tapping into the full potential of the power of “queer” as a tool to disrupt and destabilise the pervasive system of heteropatriarchy. Our contri-bution aims to reflect on our collective queer journey, orientated towards understanding and interrogating the systemic realities underlying and informing the queer appropriation of patriarchy and heteronormativity in Afri-can queer faith spaces.

Design of terbium (III)-functionalized covalent organic framework as a selective and sensitive turn-on fluorescent switch for ochratoxin A monitoring

For the first time, we develop a terbium (III)-functionalized covalent organic framework named Dpy-NhBt-COF@Tb3+, through anchoring Tb3+ onto a two-dimensional imine COF (Dpy-NhBt-COF), as the selective and sensitive turn-on fluorescent switch for ochratoxin A (OTA) monitoring. Of particular significance, Tb3+ actually plays two roles during sensing process: the specific response signal, and exclusive recognition sites for OTA, while Dpy-NhBt-COF acts as the protector for Tb3+. The sensing process involves the replacement of coordinated water molecules from Tb3+ by OTA and the energy transfer from OTA to Tb3+ centers, resulting in remarkable fluorescence emergence of Tb3+. The stabilization of Tb3+ via coordination with bipyridine of Dpy-NhBt-COF not only reduces the nonselective binding of naturally occurring ligands, but also avoids the non-radiative quenching caused by solvents molecules. As a sensing platform, Dpy-NhBt-COF@Tb3+ possesses noticeable selectivity and high sensitivity toward OTA with an ultralow detection limit of 13.5 nM and rapid response of 10 s. Taken together, our work not only demonstrates great prospect of Tb3+-functionalized COF for OTA detection, but also provides a potential way to explore other functionalized materials as promising sensors for other targets.

Stakeholder status in the identification, prioritization and management of college athletic donors

PurposeThe purpose of this study is to examine how athletic fundraising managers perceive status and seek to use status to identify, prioritize and manage stakeholders within college athletics.Design/methodology/approachTo test this purpose, the researchers use the Gioia methodology to interview 19 college athletic department fundraising officers within National Collegiate Athletics Association (NCAA) institutions. Following interviews, the data were analyzed by the researchers and structured within a first-order and second-order concept designation.FindingsInterviews show that status is an effective concept for explaining how athletic fundraisers identify and prioritize donors. Officers relied on economic (capacity) and social (passion and interest) factors to rank order donors. The results also show that athletic departments use status to manage stakeholders by rewarding their giving and escalating their commitment. Status is used in four strategies to manage the donor hierarchy: benefits, recognition, membership and access. Each strategy highlighted exclusivity and rank order.Originality/valueThere is a need to empirically test the application of status within the stakeholder theory context. These findings also contribute to the evolution of stakeholder management beyond the use of social identity theory or stakeholder salience. It helps our understanding of the evolving relationship between fundraiser and donor by recognizing the importance of capacity, passion and interests when identifying and prioritizing donors. Further, status-markers such as exclusive benefits, recognition, membership and access can be used to manage donors toward the organization's goals.

Structural basis of catalysis and substrate recognition by the NAD(H)-dependent α-d-glucuronidase from the glycoside hydrolase family 4.

Members of the glycoside hydrolase family 4 (GH4) employ an unusual glycosidic bond cleavage mechanism utilizing NAD(H) and a divalent metal ion, under reducing conditions. These enzymes act upon a diverse range of glycosides, and unlike most other GH families, homologs here are known to accommodate both α- and β-anomeric specificities within the same active site. Here, we report the catalytic properties and the crystal structures of TmAgu4B, an α-d-glucuronidase from the hyperthermophile Thermotoga maritima. The structures in three different states include the apo form, the NADH bound holo form, and the ternary complex with NADH and the reaction product d-glucuronic acid, at 2.15, 1.97 and 1.85 Å resolutions, respectively. These structures reveal the step-wise route of conformational changes required in the active site to achieve the catalytically competent state, and illustrate the direct role of residues that determine the reaction mechanism. Furthermore, a structural transition of a helical region in the active site to a turn geometry resulting in the rearrangement of a unique arginine residue governs the exclusive glucopyranosiduronic acid recognition in TmAgu4B. Mutational studies show that modifications of the glycone binding site geometry lead to catalytic failure and indicate overlapping roles of specific residues in catalysis and substrate recognition. The data highlight hitherto unreported molecular features and associated active site dynamics that determine the structure-function relationships within the unique GH4 family.

Distinct Tetracyanoquinodimethane Derivatives: Enhanced Fluorescence in Solutions and Unprecedented Cation Recognition in the Solid State.

Tetracyanoquinodimethane (TCNQ) is known to react with various amines to generate substituted TCNQ derivatives with remarkable optical and nonlinear optical characteristics. The choice of amine plays a crucial role in the outcome of molecular material attributes. Especially, mono/di-substituted TCNQ’s possessing strong fluorescence in solutions than solids are deficient. Furthermore, cation recognition in the solid-state TCNQ derivatives is yet undetermined. In this article, we present solution-enhanced fluorescence and exclusive solid-state recognition of K+ ion achieved through the selection of 4-(4-aminophenyl)morpholin-3-one (APM) having considerable π-conjugation and carbonyl (C=O) functionality, particularly in the ring. TCNQ when reacted with APM, in a single-step reaction, resulted in two well-defined distinct compounds, namely, 7,7-bis(4-(4-aminophenyl)morpholin-3-ono)dicyanoquinodimethane (BAPMDQ [1], yellow) and 7,7,8-(4-(4-aminophenyl)morpholin-3-ono)tricyanoquinodimethane (APMTQ [2], red), with increased fluorescence intensity in solutions than their solids. Crystal structure investigation revealed extensive C–H−π interactions and strong H-bonding in [1], whereas moderate to weak interactions in [2]. Surprisingly, simple mechanical grinding during KBr pellet preparation with [1, 2] triggered unidentified cation recognition with a profound color change (in ∼1 min) detected by the naked eye, accompanied by a drastic enhancement of fluorescence, proposed due to the presence of carbonyl functionality, noncovalent intermolecular interactions, and molecular assemblies in [1, 2] solids. Cation recognition was also noted with various other salts as well (KCl, KI, KSCN, NH4Cl, NH4Br, etc.). Currently, the recognition mechanism of K+ ion in [1, 2] is demonstrated by the strong electrostatic interaction of K+ ion with CO and simultaneously cation−π interaction of K+ with the phenyl ring of APM, supported by experimental and computational studies. Computational analysis also revealed that a strong cation−π interaction occurred between the K+ ion and the phenyl ring (APM) in [2] than in [1] (ΔGbinding calculated as ∼16.3 and ∼25.2 kcal mol–1 for [1] and [2], respectively) providing additional binding free energy. Thus, both electrostatic and cation−π interactions lead to the recognition. Scanning electron microscopy of drop-cast films showed microcrystalline “roses” in [1] and micro/nano “aggregates” in [2]. Optical band gap (∼3.565 eV) indicated [1, 2] as wide-band-gap materials. The current study demonstrates fascinating novel products obtained by single-pot reaction, resulting in contrasting optical properties in solutions and experiencing cation recognition capability exclusively in the solid state.

Hg2+-activated oxidase-like activity of Ag2S@graphene oxide nanozyme and its naked-eye monitoring Hg2+ application with obvious hyperchromic effect

To improve the selectivity and sensitivity for naked-eye detection of toxic Hg2+, water-soluble Ag2S nanoparticle stabilized by graphene oxide (Ag2S@GO) was identified by virtue of the high catalytic activity of nano Ag2S and the excellent physicochemical property of graphene oxide. After its structure and spectral performance were characterized and investigated, it was noted that the proposed Ag2S@GO possesses outstanding Hg2+-activated oxidase-like activity to oxidize the chromogenic substrate of 3,3′,5,5′,-tramethylbenzidine (TMB) with an obvious hyperchromic effect from colorless to blue in the presence of Hg2+ exclusively. Under the optimized conditions, the Ag2S@GO+TMB system was successfully applied for naked-eye detection of heavy metal Hg2+ in real environmental samples, with a nmol·L−1-level detection limit of 9.8 × 10–9 mol/L, an accurate recovery among 97.0–101.8% and a low standard deviation less than 3.3%. The Hg2+-activated oxidase-like activity of Ag2S@GO and its exclusive recognition mechanism to toxic Hg2+ were also proposed.

Polyubiquitin and ubiquitin-like signals share common recognition sites on proteasomal subunit Rpn1

Proteasome-mediated substrate degradation is an essential process that relies on the coordinated actions of ubiquitin (Ub), shuttle proteins containing Ub-like (UBL) domains, and the proteasome. Proteinaceous substrates are tagged with polyUb and shuttle proteins, and these signals are then recognized by the proteasome, which subsequently degrades the substrate. To date, three proteasomal receptors have been identified, as well as multiple shuttle proteins and numerous types of polyUb chains that signal for degradation. While the components of this pathway are well-known, our understanding of their interplay is unclear—especially in the context of Rpn1, the largest proteasomal subunit. Here, using nuclear magnetic resonance (NMR) spectroscopy in combination with competition assays, we show that Rpn1 associates with UBL-containing proteins and polyUb chains, while exhibiting a preference for shuttle protein Rad23. Rpn1 appears to contain multiple Ub/UBL-binding sites, theoretically as many as one for each of its hallmark proteasome/cyclosome repeats. Remarkably, we also find that binding sites on Rpn1 can be shared among Ub and UBL species, while proteasomal receptors Rpn1 and Rpn10 can compete with each other for binding of shuttle protein Dsk2. Taken together, our results rule out the possibility of exclusive recognition sites on Rpn1 for individual Ub/UBL signals and further emphasize the complexity of the redundancy-laden proteasomal degradation pathway.