Reaction Cycle Research Articles

Bartonella quintana Infection in Canada: A Retrospective Laboratory Study and Systematic Review of the Literature

Background:Bartonella quintana is a body-louse-borne bacterium. Canadian B. quintana disease has been reported primarily in populations experiencing homelessness and in Indigenous communities with limited access to water. We sought to understand the epidemiology of B. quintana in Canada. Methods: This study combined an analysis of laboratory data from Canada’s National Microbiology Laboratory (NML) with a systematic review of the literature. Laboratory data included quantitative polymerase chain reaction (qPCR) cycle threshold values and indirect immunofluorescent antibody titers with the year and province of the sample acquisition. For the systematic review, we searched PubMed, Scopus, Embase, and Web of Science for articles published before 15 July 2024, with terms related to B. quintana in Canada. Results: Thirty-three individuals with qPCR-positive B. quintana were documented in seven provinces and one territory. The number of cases increased over time (p-value = 0.005), with the greatest number of cases being reported in 2022 and 2023. The percent positivity for the B. quintana qPCR performed at the NML increased over time (p-value = 0.036). The median immunoglobulin G titer demonstrated a sustained increase starting in 2017. The systematic review identified fourteen individuals with qPCR-positive B. quintana (none had a qPCR performed at the NML) and seven probable cases of B. quintana disease. Four of these twenty-one individuals from the systematic review died (19%). All fatalities were attributed to endocarditis. Conclusions: The detection of B. quintana disease in seven provinces and one territory suggests that B. quintana has a national distribution. B. quintana disease is increasingly diagnosed in Canada, indicating ongoing transmission across geographic settings.

Fuel‐Driven π‐Conjugated Superstructures to Form Transient Conductive Hydrogels

AbstractDespite advances in creating dissipative materials with transient properties, such as hydrogels and active droplets, their application remains confined to temporal changes in structural properties. Developing out‐of‐equilibrium materials whose electronic functions are parameterized by a chemical reaction cycle is challenging. Yet, this class of materials is required to construct biomimetic materials. In contrast to traditional chemical reaction cycles that exploit molecularly dissolved building blocks at thermodynamic equilibrium, we show that fiber structures derived from reactive naphthalene diimide (NDI) building blocks can be used as resting states to form far‐from‐equilibrium conductive hydrogels after the addition of chemical fuels. Upon fueling the NDI‐derived fibers, a dual‐component activation and deactivation pathway is deduced by kinetic analysis and is absent when using a molecularly dissolved resting state. Investigating the solid‐state morphologies of the structures formed throughout the fuel‐driven reaction cycle using cryo‐EM reveals that the resting thermodynamic fibers evolve to transient thicker fibrils and layered superstructures. We show that the transient redox‐active hydrogels exhibit a nearly threefold increase in electrical conductivity upon fuel consumption before reverting to their original value over hours. These far‐from‐equilibrium materials are potential candidates in applications such as programmable biorobotics and chemical computing.

Structural Insight on the Selectivity of Calyx[4]Arene-Based Inhibitors of Mg2+-Dependent Atp-Hydrolases.

Located in plasma membranes, ATP hydrolases are involved in several dynamic transport processes, helping to control the movement of ions across cell membranes. ATP hydrolase acts as a transport protein, converting energy from ATP hydrolysis into transport molecules against their concentration gradients. In addition to energy metabolism and active transport, ATP hydrolase is essential for maintaining cellular homeostasis and cell function. This study focused on the domain architecture model of P-type ATPases, which participate in the reaction cycles of ATP hydrolysis carried out by membrane transport systems - Na+, K+-ATPase and Ca2+, Mg2+-ATPase. Targeted modulation of Na+, K+-ATPase and Ca2+, Mg2+-ATPase by unnatural drugs is of greatest interest due to the lack of known effectors. This new discovery presents a convenient model based on our recent experimental studies of the membrane structures and myocytes of the uterine smooth muscle, the myometrium. This current study strongly supports the fact that nanosized calix[4]arenes functionalised on the upper rings of the macrocycle with biologically active phosphonic acid fragments can serve as selective and potent inhibitors of cation-transporting electroenzymes. This is how we discovered that calix[4]arene of methylenebisphosphonic acid C-97 and calix[4]arene of bis-aminophosphonic acid C-107 selectively and effectively (I0.5 <100 nM) inhibit the activity of Mg2+, ATP-dependent electrogenic Na+ K+ plasma membrane pump. As drug discovery in the field of Mg2+-ATPase inhibitors is uncharted territory, basic research holds the key to explaining and predicting the mechanism of interaction and action of different classes of compounds. In light of the presented results, new calix[4]arene compounds can be used as potent inhibitors of Mg2+, ATP-dependent electrogenic ion pumps.

Solvent-free synthesis of citronellyl acetate using Fermase: Optimization, kinetics and RSM studies

Citronellyl acetate is a flavor ester with a fresh fruit aroma and a fruity, sweet flavor. The current study illustrates the synthesis of citronellyl acetate via a transesterification reaction of citronellol and vinyl acetate in a solvent-free system with the help of biocatalyst Fermase. The effect of various parameters affecting the reaction, including reactant mole ratio, enzyme loading, temperature, and agitation speed, was studied to obtain the maximum conversion of citronellol. Under optimized conditions with a 1:10 mole ratio of citronellol to vinyl acetate, 3% (w/w) enzyme loading with respect to citronellol, 300 RPM agitation speed, and 60 °C temperature, a maximum conversion of 99.8% was achieved in 2 h reaction time. The enzyme was reused for six reaction cycles, retaining 85% of its activity. Various kinetic models for enzymatic reactions were explored and validated. The ping-pong bi-bi model with both substrate inhibition gave the best fit for the experimental data. Optimization studies were also conducted using the response surface methodology to observe the interaction of various parameters.

Enhanced catalytic performance of methanol-tolerant Rhizopus stolonifera immobilized on polyurethane foam with hydrophobic coating for biodiesel production

The limited methanol tolerance and glycerol adsorption tendency of whole-cell catalysts are the main factors contributing to the extended catalytic cycle and limited catalyst reusability in biodiesel preparation. In this study, a 7.5 % methanol-tolerant Rhizopus stolonifera mutant (MTS2) was developed through the atmospheric and room temperature plasma (ARTP), exhibiting a 1.5-fold increase in methanol tolerance compared with the wild type strain (WT-RS), along with a 93.5 % increase in lipases activity. Polyurethane foam PF3 with an average pore size of 0.15 mm and 90 A rigidity is optimal for MTS2 immobilization (MTS2 @PF3), enabling its application in continuous processing for industrial applications. Utilizing soybean oil as a substrate, the catalyst MTS2 @PF3 produced 95.5 % of fatty acid methyl esters (FAME) in 36 hours under optimal conditions (30°C, 180 r/min, catalyst dosage of 15 % g/g oil, 30 % water content, and methanol addition in Scheme 3), achieving over a 50 % reduction in reaction time compared with WT-RS@PF3. To address limitations in catalyst reusability due to glycerol adsorption, various modifiers, including rosin-based modifier (RM), amino silicone oil (ASO), graphene (GRA), betaine and Tween 80 were evaluated. The glycerol adsorption rates experienced substantial reductions (39.3 % with RM and 85.6 % with betaine), and the catalysts maintained above 60 % FAME yield even after 8 reaction cycles. The combination of enhanced methanol tolerance, lipase activity, and reduced glycerol adsorption contribute to enhanced catalytic efficiency and reusability, which can reduce production costs for biodiesel manufacturing. The composite of these attributes makes MTS2 @RM1-PF3 and Betaine-MTS2 @PF3 as promising candidate for industrial biodiesel production, addressing previous limitations in catalyst performance and sustainability. The developed immobilized whole-cell catalysts exhibit promising potential for more sustainable and cost-effective processes in biodiesel manufacturing.

Direct synthesis of liquid hydrocarbons from CO2 and H2 over bifunctional ZnCrOx-НZSM-5 combined and composite catalysts in a single reactor

A one-stage synthesis of gasoline fraction from CO2 and H2 was carried out on Zn-Cr–oxide-zeolite combined and composite catalysts. It was found that after oxidative and reduction treatment the catalysts contain ZnO and ZnCr2O4 phases. The one-step coprecipitation of zinc and chromium salts in the presence of zeolite allows obtaining an active bifunctional composite catalyst, each particle of which contains Zn-Cr oxide and zeolite components. A synergistic catalysis due to a closer distance of metal and acid sites increased the efficiency of such a catalyst in CO2 hydrogenation. It was found that the optimal temperature of oxidative activation of the composite catalyst is 400 ° C. With an increase in the temperature of oxidative treatment of the composite catalyst from 400 to 500°C, part of the zinc leaves the structure of the non-stoichiometric spinel and leads to a decrease in the basicity of the catalyst, which is responsible for the activation of CO2 on surface oxygen vacancies. Agglomerated ZnO particles blocked the pores and reduced their volume, as well as the specific surface of the catalyst. At the same time, the total acidity of the catalyst decreased. ZnO-species, which have hydrogenating activity, under the reaction conditions removed alkenes from the reaction cycle and thereby reduced the C5+–selectivity of the composite catalyst. Among the studied catalysts, the ZnCrOx-НZSM-5/Al2O3(400) composite catalyst in the tail-gas recirculation mode at 380°C and 10 MPa demonstrated high CO2 conversion of 25% and high selectivity for C5+–HCs of 53 wt% with a high content of isoalkanes 71 wt% for 60 hours. The methane content in the tail-gas did not exceed 3 vol%. The results obtained will be used to develop approaches to creating effective catalysts for the one-stage CO2 hydrogenation into valuable petrochemical products.

Experimental and modeling insights into the kinetics of calcium looping CO2 capture process: Assessment of limestone treatment

This investigation aimed to offer a precise and detailed understanding of the intricate mechanisms governing the rapid and diffusion stages of carbonation within the calcium looping process, while also exploring the effects of treatment on mineral limestone (Raw limestone) as the primary sorbent for CO2 capture. Two modified samples treated with acetic acid (Acidified limestone) and hydrophobic silica nanoparticles (Silica-mixed limestone), were analyzed to provide deeper insights into the kinetics of the slow and fast stages of the carbonation reaction. The Acidified limestone had a significant influence on the carbonation conversion rates of both the rapid and slow stages, resulting in a notable enhancement in conversion efficiency. Notably, the carbonation conversion rates in the 20th cycle were measured as 0.201, 0.348, and 0.231 for the Raw, Acidified, and Silica-mixed limestones, respectively. An increase in the number of reaction cycles led to an increased percentage contribution of the diffusion stage, a decrease in transition time and consequently, a reduction in the overall carbonation conversion rate. Specifically, the share percentage of carbonation conversion for the diffusion stage in the 20th cycle was determined as 31.55%, 34.88%, and 30.36% for the Raw, Acidified, and Silica-mixed limestones, respectively. The results obtained from the modeling application demonstrated a reduction in the maximum absolute error with an increase in the reaction cycles. Additionally, the prediction results indicated that the carbonation conversion rates for the Raw and Acidified limestones in the 100th cycle were determined to be 0.07 and 0.12, respectively.

In-situ hydrogenation of dual function material for integrated CO2 capture and methanation with the presence of steam

The impacts of steam on hydrogenation of dual function materials (DFM) for Integrated CO2 Capture and in-situ methanation (ICCM) is a new area requiring detailed investigations prior to industrialization. This work investigated impacts from steams on hydrogenation of Ru-Na2CO3/γ-Al2O3 DFM for ICCM that containing Na2O adsorbent, Ru sites, and γ-Al2O3 support. DFM performance was examined in cyclic reactions as introducing external steam during hydrogenation, and the behaviors of adsorbed CO2 species during hydrogenation were characterized by in-situ DRIFTS and H2-TPSR. CH₄ selectivity decreased sharply from 84.3 % to 1.2 % as increasing external steam concentrations to 20 vol.%, and the conversion of adsorbent component decreased from 298.5 μmol g-1 to 167.1 μmol g-1. b-CO32- and m-CO32- formed at Na2CO3/γ-Al2O3 interface were the carbonate species that could be hydrogenated into CH4, some of which were desorbed into CO2 due to moisture-driven desorption effects. With the presence of external steam in H2 reactants, the conversion of carbonate species is a competing process between hydrogenation and moisture-driven desorption. In ICCM reaction with external steam present, b-CO32- was preferred to be desorbed into CO2; while for m-CO32-, desorption into CO2 by steam and hydrogenation into CH4 proceeded in parallel. Strong moisture-driven desorption effects from steam product were demonstrated in a fixed-bed reactor, which also led to rapid decrease of localized selectivity of CH4 along bed height.

Rational synthesis of FeWO4 nanozyme with sonopiezoelectric and co-catalytic activity for colorimetric detection of deferiprone

Colorimetric sensing based on nanozyme has been extensively applied in the field of biosensing. The analysis time and detection sensitivity depend on the activity of nanozyme. At present, the methods of traditional regulating the activity of nanozyme mainly include internal and external regulation. However, it is still a challenge for internal and external stimuli to coordinate the regulation of nanozyme activity. Both piezoelectricity and co-catalysis can expedite the rate limiting step (Fe3+/Fe2+cycle) of the Fenton reaction hence facilitating the peroxidase-like (POD-like) activity of nanozyme. In this study, we synthesized FeWO4 nanorod that possess sonopiezoelectric and co-catalytic properties. The Fe3+/Fe2+ cycle of FeWO4 nanorods can be boosted by the internal Fe, W co-catalytic reaction and the external ultrasound stimuli generated e−. Deferiprone (DFP), a small molecule of iron chelating agent, is used clinically to chelate excess iron in thalassemia patients. It can specifically inhibit the POD-like activity of the iron-based nanozyme due to coordination with Fe. Based on the above principles, we constructed a colorimetric sensing platform based on FeWO4 nanozyme for colorimetric detection of DFP in urine of thalassemia patients. The linear range, limit of detection and recovery of the developed colorimetric sensing method based on FeWO4 nanozyme platform are 0.1–5 μM, 0.05 μM and 97.4 % − 105.4 %, respectively. This work not only promotes the development of the method to regulate the activity of nanozyme, but also provides a simple method for the monitoring of DFP.

Biocatalysis: modern problems and applications

The review is devoted to analysis of recent advances, problems, and practical applications of enzymes in the framework of chemical enzymology and enzyme engineering. The achievements in the fundamental understanding of the molecular mechanisms of the catalytic cycle of enzymatic reactions are considered using quantum/molecular mechanics methods with supercomputer technologies and bioinformatics methods. The construction of protein biocatalysts with new properties is a fundamentally significant methodology of the bioengineering approach to solving practical problems, which is demonstrated by a number of examples. The increasing role of biocatalysis in medicine and biomedical research is illustrated by solving the problems of antibiotic synthesis and overcoming bacterial resistance to them, studying the mechanisms of neurodegenerative diseases and developing drugs to treat Alzheimer's disease, and investigation of biocatalytic processes of DNA repair and the role of mechanisms of functioning of heme peroxidases in the human body. The use of enzymes that destroy various endogenous and exogenous toxicants has been greatly developed in recent decades. The problems of using enzymes in therapy and drug delivery are analyzed. The fundamental role of enzymes in modern analysis and diagnosis is noted. The review considers a new trend in the development of bioanalytical methods using aptamers, multianalytical biochips, surface-enhanced Raman scattering systems, and bioelectroanalysis.&lt;br&gt; The bibliography includes 460 references.

Enhancing Potassium‐Ion Storage through Nanostructure Engineering and Ion‐Doped: A Case Study of Cu2+‐Doped Co0.85Se with Yolk‐Shell Structure

AbstractFabricating transition metal selenide (TMSe) anode materials with rapid K+ diffusion and high‐rate performance is crucial for the advancement of potassium‐ion batteries (PIBs), yet it remains a challenge. In this study, a Cu2+‐doped Co0.85Se@N‐doped carbon anode with an optimal concentration of Cu2+‐doped and yolk‐shell structure (denoted as Cu‐Co0.85Se@NC‐2) is developed to enhance the reaction kinetics and cycling life. The Cu2+‐doped modulates the electronic structure of the Co0.85Se interface, improves the diffusion and adsorption of K+, and further promotes the charge transport efficiency, as demonstrated by theoretical calculations and experimental results. In addition, an optimal Cu2+‐doped content is identified that is conducive to achieving the best structure and electrochemical performance. Moreover, the N‐doped carbon shell effectively enhances the conductivity of the electrode and alleviates the volume change of Co0.85Se yolk during cycling. Benefiting from the above advantages, the obtained Cu‐Co0.85Se@NC‐2 anode exhibits excellent rate performance (208.1 mA h g−1 at 10 A g−1) and cycling stability (239.7 mA h g−1 at 2 A g−1 after 500 cycles, the capacity retention rate is up to 80.4%). This work integrates nanostructure engineering and ion‐doped to provide a straightforward and effective strategy for designing advanced high‐rate TMSe anodes for next‐generation PIBs.

Keratin-reinforced encapsulation of whole cells expressing glucose isomerase: Development of robust and reusable biocatalyst microbeads.

Glucose isomerase (GI) is crucial in high-fructose corn syrup production. This study introduces a novel approach to enhance GI stability and reusability through whole-cell encapsulation of Streptomyces olivochromogenes PTCC 1457 in hybrid microbeads, utilizing keratin as a multifunctional stabilizer and cross-linker. Optimal bead formation was achieved using 2% alginate, 2-3% CaCl2, and 2.5% keratin at pH7.0 and 37-40°C. Keratin played a vital role in forming a robust and flexible matrix. Immobilization in keratin-alginate-biomass beads maintained GI activity (655 GIU·g-1) comparable to free enzyme (650 GIU·g-1), while silicate incorporation reduced activity to 234 GIU·g-1. The immobilized enzyme exhibited enhanced stability over a wider pH (6-9) and temperature (4-60°C) range compared to the free enzyme. Importantly, the immobilized GI maintained 80% of its initial activity after 20 reaction cycles. Thermogravimetric analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, and tensile testing confirmed the formation of hybrid beads with improved thermal and mechanical stability. This novel immobilization strategy, leveraging keratin's unique properties, offers a promising approach for enhancing GI stability, reusability, and storage longevity, potentially improving its industrial applicability in high-fructose corn syrup production.

Forced Dynamic Operation of Propylene Selective Oxidation to Acrolein on Bismuth-Molybdate Structured Catalysts

Forced dynamic operation (FDO) of selective oxidation of propylene to acrolein is evaluated on a structured alumina foam coated with a mixed metal oxide catalyst (bismuth molybdate-based). Reactor experiments examine feed composition modulation as a strategy to increase the yield of acrolein. At lower temperatures, separating the oxidant (O2) and reductant (C3H6) enhances propylene conversion and acrolein selectivity. Variation in the reaction-regeneration switching amplitude and frequency gives a 40% higher cycle-averaged acrolein yield compared to steady-state operation (SSO) for the same overall feed composition. The results suggest that FDO maintains a higher concentration of selective oxygen species during the propylene feed, while pre-oxidation of the catalyst maximizes the amount of selective oxygen species, leading to increased acrolein yield at the beginning of the reaction cycle. Experiments at lower temperature for both commercial promoted and in-house, unpromoted catalysts reveal both catalysts are most active and selective at their highest oxidation states.

Improving enzyme immobilization: A new carrier-based magnetic polymer for enhanced covalent binding of laccase enzyme

In the quest for effective enzyme immobilization methods, this study focuses on synthesizing carrier-based magnetic polymer to enhance the covalent binding of T. versicolor laccase. Utilizing chitosan (CS) and alginate (ALG) composites, modified with Fe3O4 magnetic nanoparticles (MNPs), we aimed to improve the enzyme's stability, reusability, and performance under varying conditions. The ionic gelation method was employed to prepare CS-ALG and CS-ALG-Fe3O4 MNPs composites, resulting in an 84 % and 91 % immobilization efficiency. The immobilized enzyme demonstrated superior thermal stability, retaining 48 % activity for CS-ALG-laccase and 67 % for CS-ALG-Fe3O4 MNPs-laccase at 70 °C, compared to 29 % for the free enzyme. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the composites, revealing significant morphological changes and successful enzyme integration. Kinetic studies indicated that immobilization increased the Vmax to 141 μmol/min for CS-ALG-laccase and 111 μmol/min for CS-ALG-Fe3O4 MNPs-laccase, while slightly reducing substrate affinity (Km) to 1.42 mM−1 and 1.32 mM−1, respectively. The immobilized laccase retained higher activity after ten reaction cycles (81 % activity for CS-ALG-Fe3O4 MNPs-laccase) and during prolonged storage (75 % activity retention), showcasing its potential for industrial applications. Additionally, the enzyme exhibited increased resistance to various organic solvents, enhancing its practical utility.

Development of a Quadruplex RT-qPCR for the Detection of Porcine Astrovirus, Porcine Sapovirus, Porcine Norovirus, and Porcine Rotavirus A

Porcine astrovirus (PoAstV), porcine sapovirus (PoSaV), porcine norovirus (PoNoV), and porcine rotavirus A (PoRVA) are newly discovered important porcine diarrhea viruses with a wide range of hosts and zoonotic potential, and their co-infections are often found in pig herds. In this study, the specific primers and probes were designed targeting the ORF1 gene of PoAstV, PoSaV, and PoNoV, and the VP6 gene of PoRVA. The recombinant standard plasmids were constructed, the reaction conditions (concentration of primers and probes, annealing temperature, and reaction cycle) were optimized, and the specificity, sensitivity, and reproducibility were analyzed to establish a quadruplex real-time quantitative RT-PCR (RT-qPCR) assay for the detection of these four diarrheal viruses. The results demonstrated that the assay effectively tested PoAstV, PoSaV, PoNoV, and PoRVA without cross-reactivity with other swine viruses, and had limits of detection (LODs) of 138.001, 135.167, 140.732, and 132.199 (copies/reaction) for PoAstV, PoSaV, PoNoV, and PoRVA, respectively, exhibiting high specificity and sensitivity. Additionally, it displayed good reproducibility, with coefficients of variation (CVs) of 0.09–1.24% for intra-assay and 0.08–1.03% for inter-assay. The 1578 clinical fecal samples from 14 cities in Guangxi Province, China, were analyzed via the developed assay. The results indicated that the clinical samples from Guangxi Province exhibited the prevalence of PoAstV (35.93%, 567/1578), PoSaV (8.37%, 132/1578), PoNoV (2.98%, 47/1578), and PoRVA (14.32%, 226/1578), and had a notable incidence of mixed infections of 18.31% (289/1578). Simultaneously, the 1578 clinical samples were analyzed with the previously established assays, and the coincidence rates of these two approaches exceeded 99.43%. This study developed an efficient and precise diagnostic method for the detection and differentiation of PoAstV, PoSaV, PoNoV, and PoRVA, enabling the successful diagnosis of these four diseases.

Мультиплексный анализ микросателлитных маркеров в ДНК-паспортизации сортов черешни

Abstract. Microsatellite DNA markers are widely used in genetic studies of many fruit crops, including sweet cherry. They provide data that improve the efficiency of breeding and genetic research. Improving the methodological aspects of SSR genotyping is an important issue in order to reduce the costs of time, reagents and consumables while maintaining the accuracy of the analysis. One of these methods is the use of multiplex PCR, when several SSR loci are analyzed in one reaction. The aim of these studies was to improve the elements of the SSR fingerprinting methodology for sweet cherry varieties by developing multiplex sets of SSR markers. As a result of testing microsatellite DNA markers in the formation of multiplex sets, optimization of such parameters as the ratio of primer concentrations of DNA markers included in one multiplex set; the number of reaction cycles, the annealing temperature of primers during PCR; the degree of dilution of PCR products during their denaturation during fragment analysis on the ABIprism automatic genetic analyzer and Nanofor 05. Eight multiplex kits were developed, including 21 microsatellite DNA markers. Data on the polymorphism of DNA markers and on the length ranges of amplified fragments are presented. The obtained multiplex kits were successfully used for DNA certification of sweet cherry varieties representing the gene pool of the South of Russia. Part of the data on the DNA profiles of sweet cherry varieties was registered as an intellectual property object in the form of a database of SSR fingerprints of sweet cherry varieties. The obtained data can also be used to assess the genetic structure and diversity of collections of genetic resources of this crop. Keywords: sweet cherry, genotyping, SSR-markers, SSR-fingerprinting, multiplex analysis

Coacervate‐Droplet Cased Synthetic Cells Regulated By Activated Carboxylic Acids (ACAs)

Regulating the formation and dissolution of active complex coacervate droplets with chemical reactions offers a powerful synthetic cell model. Such active droplets are also helpful in understanding the non‐equilibrium nature of membrane‐less organelles. Like many membrane‐less organelles, these droplets rely on high‐chemical potential reagents, like ATP, to maintain their transient nature. This study explores Activated Carboxylic Acids (ACAs) as a high chemical potential fuel to modulate the lifetime of peptide‐based coacervates through transient pH changes. We demonstrate that nitroacetic acid, a commonly used ACA, can effectively induce the formation and dissolution of coacervates by transiently altering the solution's pH. The system, comprising the zwitterionic peptide Ac‐FRGRGD‐OH and polyanions, forms coacervates upon protonation at low pH and dissolves as the pH returns to neutral. Our findings indicate that the lifetime of these synthetic cells can be fine‐tuned by varying the amount of ACA added, and the system can be refueled multiple times without significant interference from by‐products. This ACA‐driven reaction cycle is versatile, accommodating various coacervate compositions and enabling the uptake of diverse compounds, making it a valuable model for compartmentalization. The study underscores the potential of ACA‐fueled coacervates as a platform for investigating biomolecular condensates and developing synthetic life systems.

Simultaneous Formation of a Foldamer and a Self-Replicator by Out-of-Equilibrium Dynamic Covalent Chemistry.

Systems chemistry has emerged as a useful paradigm to access structures and phenomena typically exhibited by living systems, including complex molecular systems such as self-replicators and foldamers. As we progress further toward the noncovalent synthesis of life-like systems, and eventually life itself, it is necessary to gain control over assembly pathways. Dissipative chemical fueling has enabled access to stable populations of (self-assembled) structures that would normally form only transiently. Here, we report a synthetic dynamic combinatorial library, made from a single structurally simple building block, from which a self-replicator and a foldamer can emerge along two distinct and competing pathways through an inter- or intramolecular assembly process, respectively. A fueled chemical reaction cycle is then set up to generate the foldamer transiently, in the presence of the self-replicator. The partitioning of the building block between the folding and self-replication pathways and the duration of the fueled reaction cycles are controlled by adjusting the amount of the chemical fuel. An out-of-equilibrium steady state involving the two assemblies could also be achieved by using a continuous stirred tank reactor with inflow and outflow of material. This work connects the domains of folding and self-replication in synthetic systems through dissipative out-of-equilibrium chemistry. It demonstrates that foldamers and self-replicators, formed from the same building block, can stably coexist if the system is continuously supplied with energy, while at equilibrium, the Gibbs phase rule prohibits such coexistence.

Amino-acid-functionalized methanesulfonate ionic liquids as effective and reusable catalysts for oleic acid esterification

Five new amino-acid-functionalized methanesulfonate ionic liquids ([AAH][CH3SO3]-ILs) were prepared using methanesulfonic acid and amino acids (AAs). The catalytic performances of the five synthesized [AAH][CH3SO3]-ILs were evaluated for biodiesel synthesis via the esterification of oleic acid with methanol. Among them, IL [GluH][CH3SO3] exhibited the optimal catalytic activity in the oleic acid esterification. An experimental design based on the RSM-BBD was used to optimize the reaction conditions. A conversion rate of 96.8 % was attained using the [GluH][CH3SO3] catalyst for the oleic acid esterification at a catalyst load of 12 wt%, a molar ratio of 19.6:1, a reaction time of 3.5 h and a temperature of 103 °C. The [GluH][CH3SO3]-catalyzed oleic acid esterification followed first-order kinetics with the activation energy and frequency factor of 9.86 kJ·moL−1 and 0.47 min−1, respectively. The catalytic activity of the [GluH][CH3SO3] catalyst did not considerably change during ten consecutive cycles of the esterification reaction. Operational simplicity, high conversion rate along with good reusability makes the IL [GluH][CH3SO3] a promising catalyst for replacing traditional catalysts for the biodiesel preparation via the fatty acids esterification.

Structural basis for the reaction cycle and transport mechanism of human Na+-sulfate cotransporter NaS1 (SLC13A1).

Sulfate (SO42-) is a pivotal inorganic anion with essential roles in mammalian physiology. NaS1, a member of solute carrier 13 family and divalent anion/sodium symporter family, functions as a Na+-sulfate cotransporter, facilitating sulfate (re)absorption across renal proximal tubule and small intestine epithelia. While previous studies have linked several human disorders to mutations in the NaS1 gene, its transport mechanism remains unclear. Here, we report the cryo-electron microscopy structures of five distinct conformations of the human NaS1 at resolutions of 2.7 to 3.3 angstroms, revealing the substrates recognition mechanism and the conformational change of NaS1 during the Na+-sulfate cotransport cycle. Our studies delineate the molecular basis of the detailed dynamic transport cycle of NaS1. These findings advance the current understanding of the Na+-sulfate cotransport mechanism, human sulfate (re)absorption, and the implications of disease-associated NaS1 mutations.