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Covalent organic frameworks (COFs) are an emerging type of crystalline and porous photocatalysts for hydrogen evolution, however, the overall water splitting activity of COFs is rarely known. In this work, we firstly realized overall water splitting activity of β -ketoamine COFs by systematically engineering N-sites, architecture, and morphology. By in situ incorporating sub-nanometer platinum (Pt) nanoparticles co-catalyst into the pores of COFs nanosheets, both Pt@TpBpy-NS and Pt@TpBpy-2-NS show visible-light-driven overall water splitting activity, with the optimal H 2 and O 2 evolution activities of 9.9 and 4.8 μmol in 5 h for Pt@TpBpy-NS, respectively, and a maximum solar-to-hydrogen efficiency of 0.23%. The crucial factors affecting the activity including N-sites position, nano morphology, and co-catalyst distribution were systematically explored. Further mechanism investigation reveals the tiny diversity of N sites in COFs that induces great differences in electron transfer as well as reaction potential barriers. Covalent organic frameworks (COFs) are an emerging type of crystalline and porous photocatalysts for hydrogen evolution. Here, the authors report a β-ketoamine COF by systematically engineering N-sites, architecture, and morphology for improved water splitting activity.

Realization of solar‐driven aerobic organic transformation under atmospheric pressure raises the great challenge for efficiently activating O2 by tailored photocatalysts. Guided by theoretical calculation, phosphate groups are used to induce the construction of ultrathin Co phthalocyanine/g‐C3N4 heterojunctions (CoPc/P‐CN, ≈4 nm) via strengthened H‐bonding interfacial connection, achieving an unprecedented 14‐time photoactivity improvement for UV–vis aerobic 2,4‐dichlorophenol degradation compared to bulk CN by promoted activation of O2. It is validated that more •O2− radicals are produced through the improved photoreduction of O2 by accelerated photoelectron transfer from CN to the ligand of CoPc and then to the abundant single Co–N4 (II) catalytic sites, as endowed by the matched dimension, intimate interface even at the molecular level, and high CoPc dispersion of resulted heterojunctions. Interestingly, CoPc/P‐CN also exhibits outstanding photoactivities in the aerobic oxidation of aromatic alcohols. This work showcases a feasible route to realize efficient photocatalytic O2 activation by exploiting the potential of ultrathin metal phthalocyanine (MPc) assemblies with abundant single‐atom sites. More importantly, a universal facile strategy of H‐bonding‐dominating construction of MPc‐involved heterojunctions is successfully established. Ultrathin phosphate‐modulated Co phthalocyanine/g‐C3N4 heterojunctions are successfully fabricated for effective photocatalytic O2 activation via phosphate‐induced strengthened H‐bonding interfacial connection, as driven by density functional theory calculation. The accelerated charge kinetics from g‐C3N4 to the ligand of CoPc and then to the abundant single Co–N4 (II) catalytic sites for O2 is evidenced to contribute to the outstanding photocatalytic performances.

Equine infectious anemia (EIA) is an important viral disease characterized by persistent infection in equids worldwide. Most EIA cases are life-long virus carriers with low antibody reactions and without the appearance of clinical symptoms. A serological test with high sensitivity and specificity is required to detect inapparent infection. In this study, a B-cell common epitope-based blocking ELISA (bELISA) was developed using a monoclonal antibody together with the EIAV p26 protein labelled with HRP. The test has been evaluated against the standard and with field serum samples globally. This bELISA test can be completed within 75 min, and the sensitivity is higher than those of either the AGID or one commercial cELISA kit. This bELISA assay was 8–16 times more analytically sensitive than AGID, and 2 to 4 times more analytically sensitive than one cELISA kit by testing three sera from the USA, Argentina, and China, respectively. The 353 serum samples from Argentina were tested, in comparison with AGID, the diagnostic sensitivity and specificity of our bELISA assay were 100% (154/154) and 97.0% (193/199), respectively, and the accuracy of the bELISA test was 98.3%. The bELISA test developed in this study is a rapid, sensitive, specific method for the detection of EIAV infection, and could be a promising candidate for use in the monitoring of the EIA epidemic worldwide.Key points• A universal epitope-based blocking enzyme-linked immunosorbent assay (bELISA) was developed for detection of antibodies to EIAV.• The bELISA assay can be used to test EIAV serum samples from different regions of the world including North America, South America, Europe, and Asia.• The bELISA assay was evaluated in three different international labs and showed a better performance than other commercial kits.

Background An important aspect of protein design is the ability to predict changes in protein thermostability arising from single- or multi-site mutations. Protein thermostability is reflected in the change in free energy (ΔΔ G ) of thermal denaturation. Results We have developed predictive software, Prethermut, based on machine learning methods, to predict the effect of single- or multi-site mutations on protein thermostability. The input vector of Prethermut is based on known structural changes and empirical measurements of changes in potential energy due to protein mutations. Using a 10-fold cross validation test on the M-dataset, consisting of 3366 mutants proteins from ProTherm, the classification accuracy of random forests and the regression accuracy of random forest regression were slightly better than support vector machines and support vector regression, whereas the overall accuracy of classification and the Pearson correlation coefficient of regression were 79.2% and 0.72, respectively. Prethermut performs better on proteins containing multi-site mutations than those with single mutations. Conclusions The performance of Prethermut indicates that it is a useful tool for predicting changes in protein thermostability brought about by single- or multi-site mutations and will be valuable in the rational design of proteins.

Introduction In vitro embryo culture is essential for human assisted reproduction and livestock breeding, yet its efficiency remains limited owing to developmental arrest triggered by suboptimal media composition and environmental stressors. Preimplantation embryos are highly sensitive to a minor increase in osmolarity under organic osmolyte deficiency, which disrupts cell volume homeostasis to cause developmental block. However, the osmosensing mechanisms and the causal link between volume dysregulation and developmental arrest remain undefined. Elucidating these mechanisms will identify targeted osmoregulatory interventions to enhance in vitro culture efficiency. Methods This study established a porcine two-cell embryo developmental arrest model under physiological-range hyperosmotic stress (330 mOsm) and organic osmolyte deficiency, which disrupts cell volume homeostasis. Through single-embryo RNA-seq, Real-time quantitative polymerase chain reaction (RT-qPCR), H3K4me3/H3K27ac/H3K9me3/m 6 A/BrdU immunofluorescence, mitochondrial assays (MitoTracker Red and reactive oxygen species (ROS) staining), and metabolic analysis (pyruvate dehydrogenase (PDH) activity by Western blotting, fatty acid oxidation by FAOBlue staining), we identified hyperosmosis-induced developmental impairments. Rescue experiments via organic osmolyte supplementation, PDH modulation, and epigenetic interventions further defined the molecular basis of embryonic arrest. Results Here, we reveal that physiological-range hyperosmolarity in the absence of organic osmolytes disrupts cell volume homeostasis in porcine two-cell embryos, triggering developmental arrest at the S phase of the four-cell stage. This arrest coincides with aberrant maternal-to-zygotic transition, characterized by impaired maternal transcript degradation, compromised zygotic genome activation (ZGA), and coordinated dysregulation of nuclear and mitochondrial DNA transcription. Mechanistically, arrested embryos exhibit disrupted metabolic–epigenetic crosstalk, including PDH inactivation via S293 p-PDH accumulation that blocks pyruvate-to-acetyl-coenzyme A (CoA) conversion, fatty acid β-oxidation inhibition, alongside elevated mitochondrial membrane potential (MMP), increased ROS accumulation, and reduced H3K4me3 and H3K27ac modifications. Critically, while pharmacological modulation of H3K4me3/H3K27ac fails to rescue developmental defects, restoring volume homeostasis with organic osmolytes (e.g., glycine/betaine) or reactivating PDH via dichloroacetate (DCA) treatment completely reverses hyperosmotic stress-induced developmental arrest. Conclusions These findings identify that mitochondria in porcine preimplantation embryos act as osmotic stress sensors. Under conditions of extracellular organic osmolyte deficiency and elevated osmolarity, they drive metabolic reprogramming and nuclear epigenetic dysregulation, ultimately disrupting mitochondrial–nuclear communication, compromising ZGA, and inducing developmental arrest. These findings provide mechanistic insights for optimizing in vitro culture systems in reproductive technologies.

Pullulanase (EC 3.2.1.41) plays an important role in the specific hydrolysis of branch points in amylopectin. Enhancing its thermostability is required for its industrial application. In this study, rational protein design was used to improve the thermostability of PulB from Bacillus naganoensis (AB231790.1), which has strong enzymatic properties. Three positive single-site mutants (PulB-D328H, PulB-N387D, and PulB-A414P) were selected from six mutants. After incubation at 65°C for 5 min, the residual activities of PulB-D328H, PulB-N387D, and PulB-A414P were 4.5-, 1.7-, and 1.47-fold higher than PulB-WT, and their Tm values (the temperature at which half protein molecule denature) were 1.8°C, 0.4°C, and 0.9°C higher than PulB-WT, respectively. Then the final combined mutant PulB-328/387/414 was constructed. The t1/2 of it was 12.9-fold longer than that of PulB-WT at 65°C and the total increase in Tm of it (5.0°C) was almost 60% greater than the sum of individual increases (3.1°C). In addition, kinetic studies revealed that the kcat and the kcat/Km of PulB-328/387/414 increased by 38.8% and 12.9%. The remarkable improvement in thermostability and the high catalytic efficiency of PulB-328/387/414 make it suitable for industrial applications.

Of the 20 common amino acids, 18 are encoded by multiple synonymous codons. These synonymous codons are not redundant; in fact, all of codons contribute substantially to protein expression, structure and function. In this study, the codon usage pattern of genes in the E. coli was learned from the sequenced genomes of E. coli . A machine learning based method, Presyncodon was proposed to predict synonymous codon selection in E. coli based on the learned codon usage patterns of the residue in the context of the specific fragment. The predicting results indicate that Presycoden could be used to predict synonymous codon selection of the gene in the E. coli with the high accuracy. Two reporter genes ( egfp and mApple ) were designed with a combination of low- and high-frequency-usage codons by the method. The fluorescence intensity of eGFP and mApple expressed by the ( egfp and mApple ) designed by this method was about 2.3- or 1.7- folds greater than that from the genes with only high-frequency-usage codons in E. coli . Therefore, both low- and high-frequency-usage codons make positive contributions to the functional expression of the heterologous proteins. This method could be used to design synthetic genes for heterologous gene expression in biotechnology.

Background para -Nitrophenol (PNP), a priority environmental pollutant, is hazardous to humans and animals. However, the information relating to the PNP degradation pathways and their enzymes remain limited. Results Pseudomonas sp.1-7 was isolated from methyl parathion (MP)-polluted activated sludge and was shown to degrade PNP. Two different intermediates, hydroquinone (HQ) and 4-nitrocatechol (4-NC) were detected in the catabolism of PNP. This indicated that Pseudomonas sp.1-7 degraded PNP by two different pathways, namely the HQ pathway, and the hydroxyquinol (BT) pathway (also referred to as the 4-NC pathway). A gene cluster ( pdcEDGFCBA ) was identified in a 10.6 kb DNA fragment of a fosmid library, which cluster encoded the following enzymes involved in PNP degradation: PNP 4-monooxygenase (PdcA), p -benzoquinone (BQ) reductase (PdcB), hydroxyquinol (BT) 1,2-dioxygenase (PdcC), maleylacetate (MA) reductase (PdcF), 4-hydroxymuconic semialdehyde (4-HS) dehydrogenase (PdcG), and hydroquinone (HQ) 1,2-dioxygenase (PdcDE). Four genes ( pdcDEFG ) were expressed in E. coli and the purified pdcDE , pdcG and pdcF gene products were shown to convert HQ to 4-HS, 4-HS to MA and MA to β-ketoadipate respectively by in vitro activity assays. Conclusions The cloning, sequencing, and characterization of these genes along with the functional PNP degradation studies identified 4-NC, HQ, 4-HS, and MA as intermediates in the degradation pathway of PNP by Pseudomonas sp.1-7. This is the first conclusive report for both 4-NC and HQ- mediated degradation of PNP by one microorganism.

Acinetobacter sp. XMZ-26 (ACCC 05422) was isolated from soil samples obtained from glaciers in Xinjiang Province, China. The partial nucleotide sequence of a lipase gene was obtained by touchdown PCR using degenerate primers designed based on the conserved domains of cold-adapted lipases. Subsequently, a complete gene sequence encoding a 317 amino acid polypeptide was identified. Our novel lipase gene, lipA, was overexpressed in Escherichia coli. The recombinant protein (LipA) was purified by Ni-affinity chromatography, and then deeply characterised. The LipA resulted to hydrolyse pNP esters of fatty acids with acyl chain length from C2 to C16, and the preferred substrate was pNP octanoate showing a k ^sub cat^=560.52±28.32 s^sup -1^, K ^sub m^=0.075±0.008 mM, and a k ^sub cat^/K ^sub m^=7,377.29±118.88 s^sup -1^ mM^sup -1^. Maximal LipA activity was observed at a temperature of 15°C and pH 10.0 using pNP decanoate as substrate. That LipA peaked at such a low temperature and remained most activity between 5°C and 35°C indicated that it was a cold-adapted enzyme. Remarkably, this lipase retained much of its activity in the presence of commercial detergents and organic solvents, including Ninol, Triton X-100, methanol, PEG-600, and DMSO. This cold-adapted lipase may find applications in the detergent industry and organic synthesis.[PUBLICATION ABSTRACT]

The administration of NAD+ precursors is a potential approach to protect against liver damage and metabolic dysfunction. However, the effectiveness of different NAD+ precursors in alleviating metabolic disorders is still poorly elucidated. The current study was performed to compare the effectiveness of four different NAD+ precursors, including nicotinic acid (NA), niacinamide (NAM), nicotinamide riboside (NR), and nicotinamide mononucleotide (NMN) in alleviating high-glucose-induced injury to hepatocytes in a fish model, Megalobrama amblycephala. An in vitro high-glucose model was successfully established to mimic hyperglycemia-induced damage to the liver, which was evidenced by the reduced cell viability, the increased transaminase activity, and the depletion of cellular NAD+ concentration. The NAD+ precursors all improved cell viability, with the maximal effect observed in NR, which also had the most potent NAD+ boosting capacity and a significant Sirt1/3 activation effect. Meanwhile, NR presented distinct and superior effects in terms of anti-oxidative stress, inflammation inhibition, and anti-apoptosis compared with NA, NAM, and NMN. Furthermore, NR could effectively benefit glucose metabolism by activating glucose transportation, glycolysis, glycogen synthesis and the pentose phosphate pathway, as well as inhibiting gluconeogenesis. Moreover, an oral gavage test confirmed that NR presented the most potent effect in increasing hepatic NAD+ content and the NAD+/NADH ratio among four NAD+ precursors. Together, the present study results demonstrated that NR is most effective in attenuating the high-glucose-induced injury to hepatocytes in fish compared to other NAD+ precursors.