Abstract ：

端粒酶活性的分析检测对于癌症诊断、预后治疗等具有重要意义.该研究利用G-四链体(G4)DNA的金属配合物靶向发光探针[Ir(ppy)2(pip)]PF6,构建了灵敏检测癌细胞端粒酶活性的电化学发光(ECL)生物传感器.首先将引物DNA组装在电极表面,然后与癌细胞提取的端粒酶共同孵育,具有活性的端粒酶在引物末端生成端粒重复序列从而形成G4结构,随后[Ir(ppy)2(pip)]PF6通过与G4靶向作用结合到延长的序列中.结果表明[Ir(ppy)2(pip)]PF6的ECL信号与端粒酶活性呈现正相关,传感器的电化学发光强度与癌细胞浓度在10～5×105 cell/mL呈现良好的线性关系,检出限(LOD)为3 cell/mL.实验还表明了传感器具有良好的稳定性、适用性、抗干扰性和重现性,最后将该传感器用于测定真实人类血清和尿液样本中的端粒酶活性,得到了满意的结果.

Keyword ：

端粒酶活性 电化学发光 生物传感器 G-四链体 金属配合物

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Abstract ：

Surface-enhanced Raman spectroscopy(SERS) has unique advantages such as ultra-high sensitivity, fingerprint information, small samples, and non-destructive detection. The design and preparation of a SERS substrate with excellent reproducibility and stability are key factors in the further development of SERS detection technology. Hydrogel is a new type of encapsulation material; its cross-linked polymer network has a three-dimensional layered structure that can retain a large amount of water and has a good blocking effect on impurities and strong anti-interference ability. Hydrogel SERS substrate has many advantages, such as low cost, high sensitivity, rapid detection, and high throughput. In this review, the research process of SERS substrate, the advantages of hydrogel SERS substrate, and the application of hydrogel SERS substrate in the field of food, biology, and environmental detection are mainly reviewed to provide a new reference for the preparation of hydrogel SERSsubstrate. First, for the SERS substrate research process, early fixed metal nanoparticles(MNPs) rigid solid substrate, precious MNPs tend to oxidate and aggregate. SERS substrate has poor reproducibility, so it cannot analyze the surface rough samples. In the SERS substrate with MNPs modified on the flexible support material, MNPs are easy to separate in the detection process, and the sensitivity and stability of the SERS substrate are poor. The hydrogel is combined with a plasma nanostructure to obtain a SERS substrate with good uniformity and stability. Hydrogel, as the protective layer of MNPs, provides reliable size and charge selectivity for SERS analysis while maintaining high permeability.Furthermore, hydrogel SERS substrate can achieve in situ detection of the target without sample pretreatment, biocompatible composite hydrogels can be directly detected in vivo, and DNA hydrogel substrate can be accurately recognized, hydrogel modified with multiple antibodies allow for the detection of multiple analytes simultaneously, microgel with adjustable mesh size have a selective sieving effect on the target, and 3D nanostructured hydrogel provides more adsorption hotspots. The prepared hydrogel SERS particles, chips-, and patches show great potential for on-site trace analysis in food safety, biomedicine, and environmental monitoring. In conclusion, preparing hydrogel SERS substrates has good development prospects and can provide new references for future analysis and detection fields.

Keyword ：

Substrate Hydrogel Surface-enhanced Raman spectroscopy Rapid detection

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Abstract ：

The last years have witnessed remarkable advances in our understanding of the emergence and consequences of topological constraints in biological and soft matter. Examples are abundant in relation to (bio)polymeric systems and range from the characterization of knots in single polymers and proteins to that of whole chromosomes and polymer melts. At the same time, considerable advances have been made in the description of the interplay between topological and physical properties in complex fluids, with the development of techniques that now allow researchers to control the formation of and interaction between defects in diverse classes of liquid crystals. Thanks to technological progress and the integration of experiments with increasingly sophisticated numerical simulations, topological biological and soft matter is a vibrant area of research attracting scientists from a broad range of disciplines. However, owing to the high degree of specialization of modern science, many results have remained confined to their own particular fields, with different jargon making it difficult for researchers to share ideas and work together towards a comprehensive view of the diverse phenomena at play. Compelled by these motivations, here we present a comprehensive overview of topological effects in systems ranging from DNA and genome organization to entangled proteins, polymeric materials, liquid crystals, and theoretical physics, with the intention of reducing the barriers between different fields of soft matter and biophysics. Particular care has been taken in providing a coherent formal introduction to the topological properties of polymers and of continuum materials and in highlighting the underlying common aspects concerning the emergence, characterization, and effects of topological objects in different systems. The second half of the review is dedicated to the presentation of the latest results in selected problems, specifically, the effects of topological constraints on the viscoelastic properties of polymeric materials; their relation with genome organization; a discussion on the emergence and possible effects of knots and other entanglements in proteins; the emergence and effects of topological defects and solitons in complex fluids. This review is dedicated to the memory of Marek Cieplak. (c) 2024 Published by Elsevier B.V.

Keyword ：

Topology in soft condensed matter DNA topology & genome organization Topologically complex fluids Topology in living matter - protein folding Entangled proteins Polymers and polymer melts

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The proliferation of antibiotic resistant genes (ARGs) and antibiotic resistant bacteria (ARB) caused by antibiotic abuse has raised concerns about the global infectious-disease crisis. This study employed periodate (PI)/ferrate (VI) (Fe (VI)) system to disinfect Gram-negative ARB ( Escherichia coli DH5 alpha) and Gram-positive bacteria ( Bacillus subtilis ATCC6633). The PI/Fe (VI) system could inactivate 1 x 108 8 CFU/mL of Gram-negative ARB and Grampositive bacteria by 4.0 and 2.8 log in 30 min. Neutral and acidic pH, increase of PI dosage and Fe (VI) dosage had positive impacts on the inactivation efficiency of ARB, while alkaline solution and the coexistence of 10 mM Cl-,- , NO3-, 3- , SO42-and 4 2- and 20 mg/L humic acid had slightly negative impacts. The reactive species generated by PI/Fe (VI) system could disrupt the integrity of cell membrane and wall, leading to oxidative stress and lipid peroxidation. Intracellular hereditary substance, including DNA and ARGs (tetA), tetA ), would leak into the external environment through damaged cells and be degraded. The electron spin resonance analysis and quenching experiments indicated that Fe (IV)/Fe (V) played a leading role in disinfection. Meanwhile, PI/Fe (VI) system also had an efficient removal effect on sulfadiazine, which was expected to inhibit the ARGs transmission from the source.

Keyword ：

Antibiotic resistant bacteria Disinfection Antibiotic resistant genes Ferrate (VI) Periodate

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As a clinical anti-glioma agent, the therapeutic effect of carmustine (BCNU) was largely decreased because of the drug resistance mediated by O-6-alkylguanine-DNA alkyltransferase (AGT) and the blood-brain barrier (BBB). To overcome these obstacles, we synthesized a BCNU-loaded hypoxia/esterase dual stimulus-activated nanomicelle, abbreviated as T80-HACB/BCNU NPs. In this nano-system, Tween 80 acts as the functional coating on the surface of the micelle to facilitate transport across the BBB. Hyaluronic acid (HA) with active tumor-targeting capability was linked with the hypoxia-sensitive AGT inhibitors (O-6-azobenzyloxycarbonyl group) via an esterase-activated ester bond. The obtained T80-HACB/BCNU NPs had an average particle size of 232.10 +/- 10.66 nm, the zeta potential of -18.13 +/- 0.91 mV, and it showed high drug loading capacity, eximious biocompatibility and dual activation of hypoxia/esterase drug release behavior. The obtained T80-HACB/BCNU NPs showed enhanced cytotoxicity against hypoxic T98G and SF763 cells with IC50 at 132.2 mu M and 133.1 mu M, respectively. T80 modification improved the transportation of the micelle across an in vitro BBB model. The transport rate of the T80-HACB/Cou6 NPs group was 12.37 %, which was 7.6-fold (p<0.001) higher than the micelle without T80 modification. T80-HACB/BCNU NPs will contribute to the development of novel CENUs chemotherapies with high efficacy.

Keyword ：

Carmustine Hypoxia/esterase-responsive nano-micelle Target delivery

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Archaeal NurA protein plays a key role in producing 3'-single stranded DNA used for homologous recombination repair, together with HerA, Mre11, and Rad50. Herein, we describe biochemical characteristics and roles of key amino acid residues of the NurA protein from the hyperthermophilic euryarchaeon Thermococcus barophilus Ch5 (Tba-NurA). Tba-NurA possesses 5'-3' exonuclease activity for degrading DNA, displaying maximum efficiency at 45 degrees C-65 degrees C and at pH 8.0 in the presence of Mn2+. The thermostable Tba-NurA also possesses endonuclease activity capable of nicking plasmid DNA and circular ssDNA. Mutational data demonstrate that residue D49 of Tba-NurA is essential for exonuclease activity and is involved in binding ssDNA since the D49A mutant lacked exonuclease activity and reduced ssDNA binding. The R96A and R129A mutants had no detectable dsDNA binding, suggesting that residues R96 and R129 are important for binding dsDNA. The abolished degradation activity and reduced dsDNA binding of the D120A mutant suggest that residue D120 is essential for degradation activity and dsDNA binding. Additionally, residues Y392 and H400 are important for exonuclease activity since these mutations resulted in exonuclease activity loss. To our knowledge, it is the first report on biochemical characterization and mutational analysis of the NurA protein from Thermococcus. (c) 2024 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Keyword ：

NurA protein Hyperthermophilic archaea Endonuclease Exonuclease DNA repair

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G-quadruplex (G4) DNA is present in human telomere oligonucleotide sequences. Oxidative damage to telomeric DNA accelerates telomere shortening, which is strongly associated with aging and cancer. Most of the current analyses on oxidative DNA damage are based on ds-DNA. Here, we developed a electrochemiluminescence (ECL) probe for enhanced recognition of oxidative damage in G4-DNA based on DNA-mediated charge transfer (CT), which could specifically recognize damaged sites depending on the position of 8-oxoguanine (8-oxoG). First, a uniform G4-DNA monolayer interface was fabricated; the G4-DNA mediated CT properties were examined using an iridium(III) complex [Ir(ppy)2(pip)]PF6 2 (pip)]PF 6 stacked with G4-DNA as an indicator. The results showed that G4- DNA with 8-oxoG attenuated DNA CT. The topological effects of oxidative damage at different sites of G4- DNA and their effects on DNA CT were revealed. The sensing platform was also used for the sensitive and quantitative detection of 8-oxoG in G4-DNA, with a detection limit of 28.9 fmol. Overall, these findings present a sensitive platform to study G4-DNA structural and stability changes caused by oxidative damage as well as the specific and quantitative detection of oxidation sites. The different damage sites in the G-quadruplex could provide detailed clues for understanding the function of G4-associated telomere functional enzymes.

Keyword ：

G-quadruplex Iridium(III) complex Electrochemiluminescence Oxidative damage DNA CT

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Partial nitrification (PN) represents an energy-efficient bioprocess; however, it often confronts challenges such as unstable nitrite accumulation, nitrite oxidizing bacteria shocks, and slow reaction rate. This study established an acidophilic PN with self-sustained pH as low as 5.36. Over 120-day monitoring, nitrite accumulation rate (NAR) was stabilized at more than 97.9 %, and an ultra-high ammonia oxidation rate of 0.81 kg/m(3)& sdot;d was achieved. Notably, least NAR of 77.8 % persisted even under accidental nitrite oxidizing bacteria invasion, aeration delay, alkalinity fluctuations, and cooling shocks. During processing, despite detrimental effects on bacterial diversity, there was a discernible increase in acid-tolerant bacteria responsible for nitrification. Candidatus Nitrosoglobus, gradually dominated in nitrifying guild (2.15 %), with the substantially reduction or disappearance of typical nitrifying microorganisms. Acidobacteriota, a key player in nitrogen cycling of soil, significantly increased from 0.45 % to 9.98 %, and its associated nitrogen metabolism genes showed a substantial 215 % rise. AmoB emerged as the most critical functional gene influencing acidophilic PN, exhibiting significantly higher unit gene expression than other nitrification genes. Blockade tricarboxylic acid cycle, DNA damage, and presence of free nitrous acid exert substantial effects on nitrite-oxidizing bacteria (NOB), serving as internal driving forces for acidophilic PN. This highlights the reliable potential for shortening nitrogen transformation process.

Keyword ：

Ultra -fast reaction rate Candidatus nitrosoglobus Acidophilic partial nitrification pH < 6 Acidobacteriota

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Molecular catalysts have attracted significant attention because of their high activity, selectivity, and tunability. However, in heterogeneous catalysis, the uniform dispersion and immobilization of molecular catalysts on the supporting substrate remain a significant challenge due to their aggregation tendency. Here, we present a facile strategy to molecularly disperse and immobilize a series of macrocyclic metal complexes onto reduced graphene oxide (rGO) by using DNA as a mediator. The electroactive amounts of molecularly dispersed iron phthalocyanine (FePc) molecules are increased by similar to 50 times greater than that of pristine FePc catalyst. As a result, the single-molecule catalyst demonstrates a notable power density (similar to 290 mW cm(-2)) in an H-2/O-2 alkaline polymer electrolyte fuel cell. Operando X-ray absorption spectroscopy experiments combined with density functional theory calculations reveal that the coordination interaction between FePc and DNA enables the molecular dispersion and immobilization of FePc on the surface of rGO, and consequently improves the activity by regulating the electronic structure of active centers. This study points out a facile strategy to tackle the fundamental challenges facing molecular catalysts in long-lasting energy conversion technologies.

Keyword ：

iron phthalocyanine DNA energy conversion single-molecule catalysts H-2/O-2 alkaline fuel cell

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Fungal overgrowth in halophilic aerobic granular sludge (HAGS) is a severe problem, leading to granule disintegration. However, it is still mostly unclear how to control fungal overgrowth. This study explored the effects of carbon availability in saline wastewater with a salinity of 20 g/L on fungal and bacterial population sizes, community compositions, and network interactions in HAGS by manipulating different carbon-to‑nitrogen ratios (C/N). Bacterial population size increased from 6.42 × 106 copies/ng DNA to 8.67 × 106 copies/ng DNA as the C/N ratio increased from 4 to 20. In contrast, fungal population size decreased from 1.24 × 106 copies/ng DNA to 8.05 × 103 copies/ng DNA. The maximum removal rate of ammonia by fungi decreased from 5.02 ± 0.04 mg·L−1·h−1 to 1.72 ± 0.30 mg·L−1·h−1. Nitrosomonas, Thauera, and Planktosalinus competed for nutrients with the dominant fungi Cosmospora, being in antagonism. Carbon availability in the saline wastewater could regulate the population of bacteria and fungi, laying a theoretical foundation for controlling HAGS disintegration. © 2024 Elsevier B.V.

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