Dynamic control of His-hemin coordination and catalysis by reversible host-guest inclusion in peptide assemblies.

Dynamic self-assembly has significant implications in the regulation of the enzyme activities. In this study, we present a histidine-based enzyme-mimicking catalyst, formed by the self-assembly of carefully-engineered FH-based short peptides with hemin, showcasing switchable catalytic activity of hemin due to externally induced reversible inclusion of a cucurbit[7]uril-peptide hybrid. 1H NMR, ITC and theoretical simulation are employed to examine the binding affinity between the guest and host components, and UV-vis spectra are used to investigate changes in the hemin coordination environment. The histidine segment of the short peptide can be partially shielded by the cucurbituril and released following addition of the azo compound, leading to a decrease and subsequent restoration of the histidine-hemin coordination affinity and hemin activity. The photoisomeriziable nature of the azo compound enabled the activation of FHH/hemin activity to be switched on and off by exposure to different wavelengths of light. During the operation, the Phe residue remained within the cucurbituril, allowing reversible inclusion and exposure of the histidine residues. The hemin stayed connected to FHH/cucurbit[7]uril hybrid, preventing the severe aggregation of hemin and irreversible deactivation. This work may provide insights into engineering the dynamic behaviors of the cofactor-dependent catalytic assemblies.

A Host-Guest Approach to Engineering Oxidase-Mimetic Assembly with Substrate Selectivity and Dynamic Catalysis.

The creation of synthetic materials that emulate the complexity of natural systems, such as enzymes, remains a challenge in biomimicry. Here, we present a simple yet effective strategy to introduce substrate selectivity and dynamic responsiveness into an enzyme-mimetic supramolecular material. We achieved this by anchoring γ-cyclodextrin to a fluorene-modified Lys/Cu2+ assembly, which mimics copper-dependent oxidase. The binding affinity among the components was examined using 1H NMR, isothermal titration calorimetry (ITC), and theoretical simulation. The γ-cyclodextrin acts as a host, forming a complex with the fluorenyl moiety and aromatic substrates of specific sizes. This ensures the proximity of the substrate reactive groups to the copper center, leading to size-selective enhancement of aromatic substrate oxidation, particularly favoring biphenyl substrates. Notably, α- and ß-cyclodextrins do not exhibit this effect, and the native oxidase lacks this selectivity. Additionally, the binding affinity of the aromatic substrate to the catalyst can be dynamically tuned by adding α-cyclodextrin or by irradiating with different wavelengths in the presence of competitive azo-guests, resulting in switched oxidative activities. This approach offers a new avenue for designing biomimetic materials with tailorable active site structures and catalytic properties.

Effect of Acupuncture for Methadone Reduction : A Randomized Clinical Trial.

BACKGROUND: Methadone maintenance treatment (MMT) is effective for managing opioid use disorder, but adverse effects mean that optimal therapy occurs with the lowest dose that controls opioid craving. OBJECTIVE: To assess the efficacy of acupuncture versus sham acupuncture on methadone dose reduction. DESIGN: Multicenter, 2-group, randomized, sham-controlled trial. (Chinese Clinical Trial Registry: ChiCTR2200058123). SETTING: 6 MMT clinics in China. PARTICIPANTS: Adults aged 65 years or younger with opioid use disorder who attended clinic daily and had been using MMT for at least 6 weeks. INTERVENTION: Acupuncture or sham acupuncture 3 times a week for 8 weeks. MEASUREMENTS: The 2 primary outcomes were the proportion of participants who achieved a reduction in methadone dose of 20% or more compared with baseline and opioid craving, which was measured by the change from baseline on a 100-mm visual analogue scale (VAS). RESULTS: Of 118 eligible participants, 60 were randomly assigned to acupuncture and 58 were randomly assigned to sham acupuncture (2 did not receive acupuncture). At week 8, more patients reduced their methadone dose 20% or more with acupuncture than with sham acupuncture (37 [62%] vs. 16 [29%]; risk difference, 32% [97.5% CI, 13% to 52%]; P < 0.001). In addition, acupuncture was more effective in decreasing opioid craving than sham acupuncture with a mean difference of -11.7 mm VAS (CI, -18.7 to -4.8 mm; P < 0.001). No serious adverse events occurred. There were no notable differences between study groups when participants were asked which type of acupuncture they received. LIMITATION: Fixed acupuncture protocol limited personalization and only 12 weeks of follow-up after stopping acupuncture. CONCLUSION: Eight weeks of acupuncture were superior to sham acupuncture in reducing methadone dose and decreasing opioid craving. PRIMARY FUNDING SOURCE: National Natural Science Foundation of China.

Enhancing DNA-based nanodevices activation through cationic peptide acceleration of strand displacement.

Dynamic DNA-based nanodevices offer versatile molecular-level operations, but the majority of them suffer from sluggish kinetics, impeding the advancement of device complexity. In this work, we present the self-assembly of a cationic peptide with DNA to expedite toehold-mediated DNA strand displacement (TMSD) reactions, a fundamental mechanism enabling the dynamic control and actuation of DNA nanostructures. The target DNA is modified with a fluorophore and a quencher, so that the TMSD process can be monitored by recording the time-dependent fluorescence changes. The boosting effect of the peptides is found to be dependent on the peptide/DNA N/P ratio, the toehold/invader binding affinity, and the ionic strength with stronger effects observed at lower ionic strengths, suggesting that electrostatic interactions play a key role. Furthermore, we demonstrate that the cationic peptide enhances the responsiveness and robustness of DNA machinery tweezers or logic circuits (AND and OR) involving multiple strand displacement reactions in parallel and cascade, highlighting its broad utility across DNA-based systems of varying complexity. This work offers a versatile approach to enhance the efficiency of toehold-mediated DNA nanodevices, facilitating flexible design and broader applications.

Robust Oxidase-Mimetic Supramolecular Nanocatalyst for Lignin Biodegradation.

Enzymatic catalysis presents an eco-friendly, energy-efficient method for lignin degradation. However, challenges arise due to the inherent incompatibility between enzymes and native lignin. In this work, we introduce a supramolecular catalyst composed of fluorenyl-modified amino acids and Cu2+, designed based on the aromatic stacking of the fluorenyl group, which can operate in ionic liquid environments suitable for the dissolution of native lignin. Amino acids and halide anions of ionic liquids shape the copper site's coordination sphere, showcasing remarkable catechol oxidase-mimetic activity. The catalyst exhibits thermophilic property, and maintains oxidative activity up to 75 °C, which allows the catalyzed degradation of the as-dissolved native lignin with high efficiency even without assistance of the electron mediator. In contrast, at this condition, the native copper-dependent oxidase completely lost its activity. This catalyst with superior stability and activity offer promise for sustainable lignin valorization through biocatalytic routes compatible with ionic liquid pretreatment, addressing limitations in native enzymes for industrially relevant conditions.

Self-Assembly of Designed Peptides with DNA to Accelerate the DNA Strand Displacement Process for Dynamic Regulation of DNAzymes.

Toehold-mediated DNA strand displacement (TMSD) is a powerful tool for controlling DNA-based molecular reactions and devices. However, the slow kinetics of TMSD reactions often limit their efficiency and practical applications. Inspired by the chemical structures of natural DNA-operating enzymes (e.g., helicase), we designed lysine-rich peptides to self-assemble with DNA-based systems. Our approach allows for accelerating the TMSD reactions, even during multiple displacement events, enhancing their overall efficiency and utility. We found that the acceleration is dependent on the peptide's sequence, length, and concentration as well as the length of the DNA toehold domain. Molecular dynamics simulations revealed that the peptides promote toehold binding between the double-stranded target and the single-stranded invader, thereby facilitating strand displacement. Furthermore, we integrated our approach into a horseradish peroxidase-mimicking DNAzyme, enabling the dynamic modulation of enzymatic functions on and off. We anticipate that the established acceleration of strand displacement reactions and the modulation of enzymatic activities offer enhanced functionality and control in the design of programmable DNA-based nanodevices.

Histidine-Based Supramolecular Nanoassembly Exhibiting Dual Enzyme-Mimetic Functions: Altering the Tautomeric Preference of Histidine to Tailor Oxidative/Hydrolytic Catalysis.

Challenges persist in replicating enzyme-like active sites with functional group arrangements in supramolecular catalysis. In this study, we present a supramolecular material comprising Fmoc-modified histidine and copper. We also investigated the impact of noncanonical amino acids (δmH and εmH), isomers of histidine, on the catalytic process. The Fmoc-δmH-based nanoassembly exhibits an approximately 15-fold increase in oxidative activity and an ∼50-fold increase in hydrolytic activity compared to Fmoc-εmH (kcat/Km). This distinction arises from differences in basicity and ligation properties between the ε- and δ-nitrogen of histidine. The addition of guanosine monophosphate further enhances the oxidative activity of the histidine- and methylated histidine-based catalysts. The Fmoc-δmH/Cu2+-based nanoassembly catalyzes the oxidation/hydrolysis cascade of 2',7'-dichlorofluorescein diacetate, benefiting from the synergistic effect between the copper center and the nonligating ε-nitrogen of histidine. These findings advance the biomimetic catalyst design and provide insights into the mechanistic role of essential residues in natural systems.

Establishment of a model for predicting preterm birth based on the machine learning algorithm.

BACKGROUND: The purpose of this study was to construct a preterm birth prediction model based on electronic health records and to provide a reference for preterm birth prediction in the future. METHODS: This was a cross-sectional design. The risk factors for the outcomes of preterm birth were assessed by multifactor logistic regression analysis. In this study, a logical regression model, decision tree, Naive Bayes, support vector machine, and AdaBoost are used to construct the prediction model. Accuracy, recall, precision, F1 value, and receiver operating characteristic curve, were used to evaluate the prediction performance of the model, and the clinical application of the model was verified. RESULTS: A total of 5411 participants were included and were used for model construction. AdaBoost model has the best prediction ability among the five models. The accuracy of the model for the prediction of "non-preterm birth" was the highest, reaching 100%, and that of "preterm birth" was 72.73%. CONCLUSIONS: By constructing a preterm birth prediction model based on electronic health records, we believe that machine algorithms have great potential for preterm birth identification. However, more relevant studies are needed before its application in the clinic.

A designed DNA/amino acid amphiphile-based supramolecular oxidase-mimetic catalyst for colorimetric DNA detection.

DNA is self-assembled with Fmoc-amino acids and Cu2+ to construct a supramolecular catechol oxidase-mimetic catalyst, which exhibits remarkable activity in catalyzing colorimetric reactions. This catalytic system is used for the detection of DNA hybridization with a high selectivity and a low detection limit.

A nucleotide-copper(II) complex possessing a monooxygenase-like catalytic function.

The de novo design of artificial biocatalysts with enzyme-like active sites and catalytic functions has long been an attractive yet challenging goal. In this study, we present a nucleotide-Cu2+ complex, synthesized through a one-pot approach, capable of catalyzing ortho-hydroxylation reactions resembling those of minimalist monooxygenases. Both experimental and theoretical findings demonstrate that the catalyst, in which Cu2+ coordinates with both the nucleobase and phosphate moieties, forms a ternary-complex intermediate with H2O2 and tyramine substrates through multiple weak interactions. The subsequent electron transfer and hydrogen (or proton) transfer steps lead to the ortho-hydroxylation of tyramine, where the single copper center exhibits a similar function to natural dicopper sites. Moreover, Cu2+ bound to nucleotides or oligonucleotides exhibits thermophilic catalytic properties within the temperature range of 25 °C to 75 °C, while native enzymes are fully deactivated above 35 °C. This study may provide insights for the future design of oxidase-mimetic catalysts and serve as a guide for the design of primitive metallocentre-dependent enzymes.

A supramolecular metalloenzyme possessing robust oxidase-mimetic catalytic function.

Enzymes fold into unique three-dimensional structures to distribute their reactive amino acid residues, but environmental changes can disrupt their essential folding and lead to irreversible activity loss. The de novo synthesis of enzyme-like active sites is challenging due to the difficulty of replicating the spatial arrangement of functional groups. Here, we present a supramolecular mimetic enzyme formed by self-assembling nucleotides with fluorenylmethyloxycarbonyl (Fmoc)-modified amino acids and copper. This catalyst exhibits catalytic functions akin those of copper cluster-dependent oxidases, and catalytic performance surpasses to date-reported artificial complexes. Our experimental and theoretical results reveal the crucial role of periodic arrangement of amino acid components, enabled by fluorenyl stacking, in forming oxidase-mimetic copper clusters. Nucleotides provide coordination atoms that enhance copper activity by facilitating the formation of a copper-peroxide intermediate. The catalyst shows thermophilic behavior, remaining active up to 95 °C in an aqueous environment. These findings may aid the design of advanced biomimetic catalysts and offer insights into primordial redox enzymes.

Thiol-Aldehyde Polycondensation for Bio-based Adaptable and Degradable Phenolic Polymers.

Designing sustainable materials with tunable mechanical properties, intrinsic degradability, and recyclability from renewable biomass through a mild process has become vital in polymer science. Traditional phenolic resins are generally considered to be not degradable or recyclable. Here we report the design and synthesis of linear and network structured phenolic polymers using facile polycondensation between natural aldehyde-bearing phenolic compounds and polymercaptans. Linear phenolic products are amorphous with Tg between -9 °C and 12 °C. Cross-linked networks from vanillin and its di-aldehyde derivative exhibited excellent mechanical strength between 6-64 MPa. The connecting dithioacetals are associatively adaptable strong bonds and susceptible to degradation in oxidative conditions to regenerate vanillin. These results highlight the potential of biobased sustainable phenolic polymers with recyclability and selective degradation, as a complement to the traditional phenol-formaldehyde resins.

Succession of endophytic bacterial community and its contribution to cinnamon oil production during cinnamon shade-drying process.

Cinnamon oil is a blend of secondary metabolites and is widely used as spice. Endophytic bacteria are always related to the secondary metabolites production. However, the potential of endophytic bacteria communities for cinnamon oil production during cinnamon shade-drying process is still not clear. In this study, we investigated the composition and metabolic function of endophytic bacterial community during 80-day shade-drying process. The temporal dynamics of essential oil content and its dominant constituents were analyzed. The succession of endophytic bacterial community from d0 to d80 was identified. The influence of endophytic bacterial community evolution on cinnamon oil is significant positive. Predictive functional analysis indicated that shade-drying process was rich in Saccharopolyspora that produce enzymes for the conversion of phenylalanine to cinnamaldehyde. These findings enhance our understanding of the functional bacterial genera and functional genes involved in the production of cinnamon oil during cinnamon shade-drying process.

Synthesis, Herbicidal Activity and Toxicity Evaluation of Secondary Ammonium Salts from Turpentine Oil for Sustainable Weed Control.

Three series of secondary ammonium chloride from turpentine were synthesized and evaluated as botanical herbicides. The preemergence herbicidal activities against ryegrass (Loliun multiflorum) and barnyard grass (Echinochloa crus-galli) were investigated using water as the only solvent. Their toxicity was evaluated by cytotoxicity assays. Preliminary results demonstrated that the herbicidal performance of the prepared salts was similar or much higher than that of corresponding secondary amines and even commercial herbicide glyphosate. Promisingly, compound 14e containing a cyclohexyl-substituted p-menthene skeleton with an IC50 value of 0.0014 mM against root growth of ryegrass showed 39-fold higher herbicidal activity than glyphosate. Besides, this compound was found to be nontoxic to human and animal cells, indicating the potential application as a water-soluble herbicide for ryegrass control.

Hashing-Based Undersampling Ensemble for Imbalanced Pattern Classification Problems.

Undersampling is a popular method to solve imbalanced classification problems. However, sometimes it may remove too many majority samples which may lead to loss of informative samples. In this article, the hashing-based undersampling ensemble (HUE) is proposed to deal with this problem by constructing diversified training subspaces for undersampling. Samples in the majority class are divided into many subspaces by a hashing method. Each subspace corresponds to a training subset which consists of most of the samples from this subspace and a few samples from surrounding subspaces. These training subsets are used to train an ensemble of classification and regression tree classifiers with all minority class samples. The proposed method is tested on 25 UCI datasets against state-of-the-art methods. Experimental results show that the HUE outperforms other methods and yields good results on highly imbalanced datasets.

Development and validation of ferroptosis-related lncRNAs signature for hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) with high heterogeneity is one of the most frequent malignant tumors throughout the world. However, there is no research to establish a ferroptosis-related lncRNAs (FRlncRNAs) signature for the patients with HCC. Therefore, this study was designed to establish a novel FRlncRNAs signature to predict the survival of patients with HCC. METHOD: The expression profiles of lncRNAs were acquired from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database. FRlncRNAs co-expressed with ferroptosis-related genes were utilized to establish a signature. Cox regression was used to construct a novel three FRlncRNAs signature in the TCGA cohort, which was verified in the GEO validation cohort. RESULTS: Three differently expressed FRlncRNAs significantly associated with prognosis of HCC were identified, which composed a novel FRlncRNAs signature. According to the FRlncRNAs signature, the patients with HCC could be divided into low- and high-risk groups. Patients with HCC in the high-risk group displayed shorter overall survival (OS) contrasted with those in the low-risk group (P < 0.001 in TCGA cohort and P = 0.045 in GEO cohort). This signature could serve as a significantly independent predictor in Cox regression (multivariate HR > 1, P < 0.001), which was verified to a certain extent in the GEO cohort (univariate HR > 1, P < 0.05). Meanwhile, it was also a useful tool in predicting survival among each stratum of gender, age, grade, stage, and etiology,etc. This signature was connected with immune cell infiltration (i.e., Macrophage, Myeloid dendritic cell, and Neutrophil cell, etc.) and immune checkpoint blockade targets (PD-1, CTLA-4, and TIM-3). CONCLUSION: The three FRlncRNAs might be potential therapeutic targets for patients, and their signature could be utilized for prognostic prediction in HCC.

Effects of treatment status and life quality on anxiety in MMT patients.

BACKGROUND: Anxiety, an important factor that affects the therapeutic effect and preservation rate of methadone maintenance treatment, has a high prevalence among MMT patients. This study aims to investigate the effects of treatment status and life quality on anxiety in MMT patients. METHODS: One hundred and Seventy-seven methadone maintenance treatment users in Guangzhou, China were evaluated. The socio-demographic, duration and MMT-related characteristics were documented. Anxiety level and quality of life were evaluated by Beck Anxiety inventory (BAI) and the Quality of Life-Drug Addiction (QOL-DA) respectively. The correlation between different factors and BAI score was also analyzed. RESULTS: The BAI total score and the QOL-DA score were 7.1±8.2, 163.5±21.4 respectively. 30.5% of the subjects showed mild to severe anxiety. Treatment interruption and QOL-DA score had strong correlations with the score of BAI, with correlation coefficients of 0.17 and - 0.08 respectively. CONCLUSIONS: Anxiety symptoms were commonly presented in MMT patients. Treatment interruption and quality of life are two major factors affecting anxiety of MMT patients.

Design, synthesis, and herbicidal activity of sec-p-menthane-7-amine derivatives as botanical herbicides.

In this study, a series of novel p-menthane type secondary amines (sec-p-menthane-7-amine derivatives 3a-3y) were synthesized and then characterized by FTIR, 1H NMR, 13C NMR, and HRMS. The post-emergence herbicidal activities of these amines against barnyard grass and rape were evaluated by the culture dish method. Most of the sec-p-menthane-7-amine derivatives showed excellent herbicidal activities equivalent to or even higher than either diuron or glyphosate. The alkyl-substituted derivatives were more active than the phenyl-substituted derivatives. The herbicidal activities of compounds 3p, 3r, 3u, and 3w against the root growth of barnyard grass were 404% higher, respectively, than those of glyphosate. The herbicidal activities of compounds 3q, 3v, 3w, and 3x against the root growth of rape were 561%, 494%, 491%, and 544% higher, respectively, than those of diuron, and 484%, 760%, 423%, and 665% higher respectively, than those of diuron against shoot growth of rape. In addition, compounds 3p, 3u, and 3v are almost harmless to rice, wheat, sorghum, maize, and peanuts at a concentration of 100 mg L-1. Most of the compounds are nontoxic to HUVEC-C and BALB/c 3T3 cells. It is indicated that the title compounds could be utilized as botanical herbicides for future weed control.

Synthesis and biological activity of pyridine acylhydrazone derivatives of isopimaric acid.

Pyridine acylhydrazone derivatives of isopimaric acid were synthesized and characterized. The minimum inhibitory concentrations of the compounds against five bacteria were determined and most of the compounds displayed some degree of antibacterial activity. The results showed that antimicrobial activity against Streptococcus pneumoniae improved when halogen atoms were introduced into the isopimaric acid, especially when one bromine atom was introduced in the para-position of isopimaric acid. Compound isopimaric acid (5-bromo pyridine-2-formaldehyde) acylhydrazone exhibited a significant antitumorial activity against hepatocarcioma cells (HepG-2) and breast cancer cells (MDA-MB-231), with inhibition degrees of 74.21% and 70.39%, respectively, at 100 µM.[Formula: see text].