Involvement of anti-oxidative enzymes, photosynthetic pigments and flavonoid metabolism in the adaptation of Reaumuria soongorica to salt stress

Reaumuria soongorica is a short woody shrub widely found in semi-arid areas of China. It can survive severe environ- mental stress including high salinity in its natural habitat. Thus, we investigated the involvement of anti-oxidative enzymes, photosynthetic pigments and flavonoid metabolism in the adaptation of R. soongorica to saline environments. R. soon- gorica was treated with 0, 100, 200 and 400 mM NaC1 solutions for 14 days. Soil salt content increased significantly by watering with high content of NaC1 solution, and no variation between 8 and 14 days during treatment. The levels ofpe- roxidation of lipid membranes （measured by malondialdehyde content） and the activities of three antioxidant enzymes （superoxide dismutase （SOD）, peroxidase （POD） and ascorbate peroxidase （APX）） increased under salt stress. Chlorophyll and carotenoid content decreased with increasing salt content. The ratio of Chl a/Chl b and carotenoid/Chl exhibited sig- nificant increase under 400 mM NaC1. However, total flavonoid and anthocyanin contents and key enzyme activities in the flavonoid pathway including phenylalanine ammonialyase （PAL） and Chalcone isomerase （CHI） decreased under salt stress. These findings possibly suggest that R. soongorica has an adaptation protection mechanism against salt-induced oxidative damage by inducin~ the activity of antioxidant enzymes and maintaining a steady level of carotenoid/Chl.

Timosaponin AⅢ induces drug-metabolizing enzymes by activating constitutive androstane receptor (CAR) via dephosphorylation of the EGFR signaling pathway

The current study aimed to assess the effect of timosaponin AⅢ(T-AⅢ)on drug-metabolizing enzymes during anticancer therapy.The in vivo experiments were conducted on nude and ICR mice.Following a 24-day administration of T-AⅢ,the nude mice exhibited an induction of CYP2B10,MDR1,and CYP3A11 expression in the liver tissues.In the ICR mice,the expression levels of CYP2B10 and MDR1 increased after a three-day T-AⅢ administration.The in vitro assessments with HepG2 cells revealed that T-AⅢ induced the expression of CYP2B6,MDR1,and CYP3A4,along with constitutive androstane receptor(CAR)activation.Treatment with CAR siRNA reversed the T-AⅢ-induced increases in CYP2B6 and CYP3A4 expression.Furthermore,other CAR target genes also showed a significant increase in the expression.The up-regulation of murine CAR was observed in the liver tissues of both nude and ICR mice.Subsequent findings demonstrated that T-AⅢ activated CAR by inhibiting ERK1/2 phosphorylation,with this effect being partially reversed by the ERK activator t-BHQ.Inhibition of the ERK1/2 signaling pathway was also observed in vivo.Additionally,T-AⅢ inhibited the phosphorylation of EGFR at Tyr1173 and Tyr845,and suppressed EGF-induced phosphorylation of EGFR,ERK,and CAR.In the nude mice,T-AⅢ also inhibited EGFR phosphorylation.These results collectively indicate that T-AⅢ is a novel CAR activator through inhibition of the EGFR pathway.

Engineering high amylose and resistant starch in maize by CRISPR/Cas9-mediated editing of starch branching enzymes

To improve the amylose content(AC)and resistant starch content(RSC)of maize kernel starch,we employed the CRISPR/Cas9 system to create mutants of starch branching enzyme I(SBEI)and starch branching enzyme IIb(SBEIIb).A frameshift mutation in SBEI(E1,a nucleotide insertion in exon 6)led to plants with higher RSC(1.07%),lower hundred-kernel weight(HKW,24.71±0.14 g),and lower plant height(PH,218.50±9.42 cm)compared to the wild type(WT).Like the WT,E1 kernel starch had irregular,polygonal shapes with sharp edges.A frameshift mutation in SBEIIb(E2,a four-nucleotide deletion in exon 8)led to higher AC(53.48%)and higher RSC(26.93%)than that for the WT.E2 kernel starch was significantly different from the WT regarding granule morphology,chain length distribution pattern,X-ray diffraction pattern,and thermal characteristics;the starch granules were more irregular in shape and comprised typical B-type crystals.Mutating SBEI and SBEIIb(E12)had a synergistic effect on RSC,HKW,PH,starch properties,and starch biosynthesis-associated gene expression.SBEIIa,SS1,SSIIa,SSIIIa,and SSIIIb were upregulated in E12 endosperm compared to WT endosperm.This study lays the foundation for rapidly improving the starch properties of elite maize lines.

Anti-oxidative stress treatment and current clinical trials

Oxidative stress disturbs the balance between the production of reactive oxygen species(ROS)and the detoxification biological process.It plays an important role in the development and progression of many chronic diseases.Upon exposure to oxidative stress or the inducers of ROS,the cellular nucleus undergoes some biological processes via different signaling pathways,such as stress adaption through the forkhead box O signaling pathway,inflammatory response through the IκB kinase/nuclear factor-κB signaling pathway,hypoxic response via the hypoxia-inducible factor/prolyl hydroxylase domain proteins pathway,DNA repair or apoptosis through the p53 signaling pathway,and antioxidant response through the Kelch-like ECH-associated protein 1/nuclear factor E2-related factor 2 signaling pathway.These processes are involved in many diseases.Therefore,oxidative stress has gained more attraction as a targeting process for disease treatment.Meanwhile,anti-oxidative stress agents have been widely explored in pre-clinical trials.However,only limited clinical trials are performed to evaluate the efficacy of anti-oxidative stress agents or antioxidants in diseases.In this letter,we further discuss the current clinical trials related to anti-oxidative stress treatment in different diseases.More pre-clinical studies and clinical trials are expected to use anti-oxidative stress strategies as disease treatment or dietary supplementation to improve disease treatment outcomes.

The Effect of Soil Enzymes and Polysaccharides Secreted by the Roots of Salvia miltiorrhiza Bunge under Drought,High Temperature,and Nitrogen and Phosphorus Deficits

Root exudates serve as crucial mediators for information exchange between plants and soil,and are an important evolutionary mechanism for plants’adaptation to environmental changes.In this study,15 different abiotic stress models were established using various stress factors,including drought(D),high temperature(T),nitrogen deficiency(N),phosphorus deficiency(P),and their combinations.We investigated their effects on the seedling growth of Salvia miltiorrhiza Bunge and the activities of Solid-Urease(S-UE),Solid-Nitrite Reductase(S-NiR),Solid-Nitrate Reductase(S-NR),Solid-Phosphotransferase(S-PT),and Solid-Catalase(S-CAT),as well as the contents of polysaccharides in the culture medium.The results showed that the growth of S.miltiorrhiza was inhibited under 15 stress conditions.Among them,13 stress conditions increased the root-shoot ratio.These 15 stress conditions significantly reduced the activity of S-NR,two combinations significantly improved the activity of S-NIR,they were synergistic stresses of high temperature and nitrogen deficiency(TN),and synergistic stresses of drought and nitrogen deficiency(DN)(p<0.05).The activity of S-UE was significantly improved under N,D,T,synergistic stresses of drought and high temperature(DT),DN,synergistic stresses of drought and phosphorus deficiency(DP),and synergistic stresses of high temperature,nitrogen,and phosphorus deficiency(TNP)stress conditions(p<0.05).Most stress combinations reduced the activity of S-PT,but D and T significantly improved it.(p<0.05).The N,DN,and TN stress conditions significantly reduced S-CAT activity.The P,DT,and synergistic stresses of drought,high temperature,and phosphorus deficiency(DTP)significantly decreased the total polysaccharide content of the soil(p<0.05).The research suggested that abiotic stress hindered the growth of S.miltiorrhiza and altered the behavior of root secretion.Roots regulated the secretion of several substances in response to various abiotic stresses,including soil nitrogen cycle enzymes,phosphorus transport-related enzymes,and antioxidant enzymes.In conclusion,plants regulate the utilization of rhizosphere substances in response to abiotic stresses by modulating the exudation of soil enzymes and polysaccharides by the root system.At the same time,soil carbon sequestration was affected by the adverse environment,which restricted the input of organic matter into the soil.

Screening for metabolic dysfunction-associated fatty liver disease:Time to discard the emperor’s clothes of normal liver enzymes?

Metabolic dysfunction-associated fatty liver disease(MAFLD)is the most prevalent chronic liver condition worldwide.Current liver enzyme-based screening methods have limitations that may missed diagnoses and treatment delays.Regarding Chen et al,the risk of developing MAFLD remains elevated even when alanine aminotransferase levels fall within the normal range.Therefore,there is an urgent need for advanced diagnostic techniques and updated algorithms to enhance the accuracy of MAFLD diagnosis and enable early intervention.This paper proposes two potential screening methods for identifying individuals who may be at risk of developing MAFLD:Lowering these thresholds and promoting the use of noninvasive liver fibrosis scores.

Expression level of myocardial enzymes in patients with schizophrenia: Predictive value in the occurrence of violence

BACKGROUND Schizophrenic patients are prone to violence,frequent recurrence,and difficult to predict.Emotional and behavioral abnormalities during the onset of the disease,resulting in active myocardial enzyme spectrum.AIM To explored the expression level of myocardial enzymes in patients with schizo-phrenia and its predictive value in the occurrence of violence.METHODS A total of 288 patients with schizophrenia in our hospital from February 2023 to January 2024 were selected as the research object,and 100 healthy people were selected as the control group.Participants’information,clinical data,and labo-ratory examination data were collected.According to Modified Overt Aggression Scale score,patients were further divided into the violent(123 cases)and non-violent group(165 cases).RESULTS The comparative analysis revealed significant differences in serum myocardial enzyme levels between patients with schizophrenia and healthy individuals.In the schizophrenia group,the violent and non-violent groups also exhibited different levels of serum myocardial enzymes.The levels of myocardial enzymes in the non-violent group were lower than those in the violent group,and the patients in the latter also displayed aggressive behavior in the past.CONCLUSION Previous aggressive behavior and the level of myocardial enzymes are of great significance for the diagnosis and prognosis analysis of violent behavior in patients with schizophrenia.By detecting changes in these indicators,we can gain a more comprehensive understanding of a patient’s condition and treatment.

Higher dietary protein increases growth performance,anti-oxidative enzymes activity and transcription of heat shock protein 70 in the juvenile sea urchin(Strongylocentrotus intermedius)under a heat stress

This study was conducted to investigate the effect of dietary protein concentration(12%,18%,24%,30% and 36%)on the growth performance,activity of anti-oxidative enzymes and heat shock protein 70(HSP70)transcription in the sea urchin(Strongylocentrotus intermedius)under a heat stress.After 112 days of feeding trial the sea urchins were heat stressed(26
C)and the coelomic fluid and intestine sampled at time 0 and 15 min,2 h and 6 h.The results showed that an increase in dietary protein(12%-24%),significantly increased(p<0.05)the sea urchin weight gain rate(WGR).As dietary protein increased(from 18% to 36%),the gonadosomatic index(GI)of juvenile sea urchins also significantly increased(p<0.05)from 18.0%to 22.6%.Superoxide dismutase(SOD)activity increased with dietary protein increase(12%-30%)and the enzyme activity was significantly higher(p<0.05)in the coelomic fluid of sea urchins that were fed with 30% diets when compared to 12% and 36% protein diets at all time points after the heat stress.Catalase(CAT)activity showed a similar tendency with the increase in dietary protein concentration at time 0 and 15 min after the heat stress(p<0.05).Transcription of HSP70 in the intestine also showed a similar trend to SOD and was highest in the animals that were fed with 30% protein diets(p<0.05).Our results suggest that 24% protein diets could meet the requirements for growth performance but a 30% protein diet resulted in improved gonad development and anti-heat stress capacity in this sea urchin species.

Effects of Zn Stress on Zn Accumulation and Anti-Oxidant Enzymes Activity in Four Varieties of Ryegrass

We investigated the influence of different content of Zn^2＋（0, 2, 4, 8, 16 mmol·kg^-1） on plant growth, activities of peroxidase （POD） and superoxide dismutase （SOD）, free proline content and Zn accumulation in four varieties of ryegrass （Loliurn perenne L.） hy pot cuhure experiment. The results showed that plant hiomass increased at the ranges of 0-2 （Tuoya）, 0-4 （Yey- ing）, 0-8 mmol·kg^-1（Airuisi and Taide）, respectively, and then decreased under excess Zn. The activities of POD ,SOD and proline content in shoots decreased firstly, and then increased with the in crease of Zn content. The plaut biomass, activities of POD and SOD in Taide were evidently higher than in the other three varie ties. Root tolerance index （RTI） and Zn transport ratio from root to shoot （S/R） in Taide were exceed 1. 0. The maximum of Zn content was 583.9 mg/kg （ at 16 mmol·kg^-1） in Taide＇s shoot.

Plant-Derived Enzymes Producing Chiral Aroma Compounds and Potential Application

Aroma(volatile)compounds play important ecological functions in plants,and also contribute to the quality of plant-derived foods.Moreover,chiral aroma compounds affect their functions in plants and lead to different flavor quality properties.Formations of chiral aroma compounds are due to the presence of enzymes producing these compounds in plants,which are generally involved in the final biosynthetic step of the aroma compounds.Here,we review recent progress in research on the plant-derived enzymes producing chiral aroma compounds,and their changes in response to environmental factors.The chiral aroma enzymes that have been reported produce(R)-linalool,(S)-linalool,(R)-limonene,and(S)-limonene,etc.,and these enzymes are found in various plant species.We also discuss the origins of enantioselectivity in the plant-derived enzymes producing chiral aroma compounds and summarize the potential use of plants containing enzymes producing chiral aroma compounds for producing chiral flavors/fragrances.

Changes in the activities of key enzymes and the abundance of functional genes involved in nitrogen transformation in rice rhizosphere soil under different aerated conditions

Soil microorganisms play important roles in nitrogen transformation. The aim of this study was to characterize changes in the activity of nitrogen transformation enzymes and the abundance of nitrogen function genes in rhizosphere soil aerated using three different methods(continuous flooding(CF), continuous flooding and aeration(CFA), and alternate wetting and drying(AWD)). The abundances of amoA ammonia-oxidizing archaea(AOA) and ammonia-oxidizing bacteria(AOB), nirS, nirK, and nifH genes, and the activities of urease, protease, ammonia oxidase, nitrate reductase, and nitrite reductase were measured at the tillering(S1), heading(S2), and ripening(S3) stages. We analyzed the relationships of the aforementioned microbial activity indices, in addition to soil microbial biomass carbon(MBC) and soil microbial biomass nitrogen(MBN), with the concentration of soil nitrate and ammonium nitrogen. The abundance of nitrogen function genes and the activities of nitrogen invertase in rice rhizosphere soil were higher at S2 compared with S1 and S3 in all treatments. AWD and CFA increased the abundance of amoA and nifH genes, and the activities of urease, protease, and ammonia oxidase, and decreased the abundance of nirS and nirK genes and the activities of nitrate reductase and nitrite reductase, with the effect of AWD being particularly strong. During the entire growth period, the mean abundances of the AOA amoA, AOB amoA, and nifH genes were 2.9, 5.8, and 3.0 higher in the AWD treatment than in the CF treatment, respectively, and the activities of urease, protease, and ammonia oxidase were 1.1, 0.5, and 0.7 higher in the AWD treatment than in the CF treatment, respectively. The abundances of the nirS and nirK genes, and the activities of nitrate reductase and nitrite reductase were 73.6, 84.8, 10.3 and 36.5% lower in the AWD treatment than in the CF treatment, respectively. The abundances of the AOA amoA, AOB amoA, and nifH genes were significantly and positively correlated with the activities of urease, protease, and ammonia oxidase, and the abundances of the nirS and nirK genes were significantly positively correlated with the activities of nitrate reductase. All the above indicators were positively correlated with soil MBC and MBN. In sum, microbial activity related to nitrogen transformation in rice rhizosphere soil was highest at S2. Aeration can effectively increase the activity of most nitrogen-converting microorganisms and MBN, and thus promote soil nitrogen transformation.

Role of renin-angiotensin system/angiotensin converting enzyme-2 mechanism and enhanced COVID-19 susceptibility in type 2 diabetes mellitus

Coronavirus disease 2019(COVID-19)is a disease that caused a global pandemic and is caused by infection of severe acute respiratory syndrome coronavirus 2 virus.It has affected over 768 million people worldwide,resulting in approx-imately 6900000 deaths.High-risk groups,identified by the Centers for Disease Control and Prevention,include individuals with conditions like type 2 diabetes mellitus(T2DM),obesity,chronic lung disease,serious heart conditions,and chronic kidney disease.Research indicates that those with T2DM face a hei-ghtened susceptibility to COVID-19 and increased mortality compared to non-diabetic individuals.Examining the renin-angiotensin system(RAS),a vital regulator of blood pressure and pulmonary stability,reveals the significance of the angiotensin-converting enzyme(ACE)and ACE2 enzymes.ACE converts angiotensin-I to the vasoconstrictor angiotensin-II,while ACE2 counters this by converting angiotensin-II to angiotensin 1-7,a vasodilator.Reduced ACE2 exp-ression,common in diabetes,intensifies RAS activity,contributing to conditions like inflammation and fibrosis.Although ACE inhibitors and angiotensin receptor blockers can be therapeutically beneficial by increasing ACE2 levels,concerns arise regarding the potential elevation of ACE2 receptors on cell membranes,potentially facilitating COVID-19 entry.This review explored the role of the RAS/ACE2 mechanism in amplifying severe acute respiratory syndrome cor-onavirus 2 infection and associated complications in T2DM.Potential treatment strategies,including recombinant human ACE2 therapy,broad-spectrum antiviral drugs,and epigenetic signature detection,are discussed as promising avenues in the battle against this pandemic.

Fat,oil,and grease as new feedstock towards bioelectrogenesis in microbial fuel cells:Microbial diversity,metabolic pathways,and key enzymes

Microbial fuel cells(MFCs)are a well-known technology used for bioelectricity production from the decomposition of organic waste via electroactive microbes.Fat,oil,and grease(FOG)as a new substrate in the anode and microalgae in the cathode were added to accelerate the electrogenesis.The effect of FOG concentrations(0.1%,0.5%,1%,and 1.5%)on the anode chamber was investigated.The FOG degradation,volatile fatty acid(VFAs)production,and soluble chemical oxygen demand along with voltage output kinetics were analyzed.Moreover,the microbial community analysis and active functional enzymes were also evaluated.The maximum power and current density were observed at 0.5%FOG which accounts for 96 mW m^(-2)(8-folds enhancement)and 560 mA m^(-2)(3.7-folds enhancement),respectively.The daily voltage output enhanced upto 2.3-folds with 77.08%coulombic efficiency under 0.5%FOG,which was the highest among all the reactors.The 0.5%FOG was degraded>85%,followed by a 1%FOG-loaded reactor.The chief enzymes inβ-oxidation and electrogenesis were acetyl-CoA C-acetyltransferase,riboflavin synthase,and riboflavin kinase.The identified enzymes symbolize the presence of Clostridium sp.(>15%)and Pseudomonas(>10%)which served as electrochemical active bacteria(EAB).The major metabolic pathways involved in electrogenesis and FOG degradation were fatty acid biosynthesis and glycerophospholipid metabolism.Utilization of lipidic-waste(such as FOG)in MFCs could be a potential approach for simultaneous biowaste utilization and bioenergy generation.

Toxicity of Tagetes erecta Essential Oil Based Combinatorial Formulations on Various Metabolic Enzymes in Indian White Termite Odontotermes obesus

Plant essential oils and their constituents have proven to be very effective against insects, especially termites. They are the best alternative to synthetic pesticides that are harmless to the environment and human health. In the present study, different enzymes, namely alkaline phosphatase, acid phosphatase, glutamate-oxaloacetate transaminase, glutamate-pyruvate transaminase and acetylcholinesterase, were evaluated in Indian termite Odontotermes obesus in a combination preparation based on Tagetes erecta essential oil. For the study of anti-termite effects against worker termites were treated topically with 40% and 80% of the 24-hour LD50 values of various combination formulations. Subsequent bioassays at 40% and 80% of LD50 of combinatorial preparations S-AST-A, S-AST-B, and S-AST-C resulted in a significant (p > 0.05) decrease in glutamate-oxaloacetate transaminase. After 16 hours of treatment, they were 87.92%, 80.17%, 89.30%, 79.17%, 81.92% and 73.17% respectively. In vivo exposures of 40% and 80% of the LD50 of the combination formulation caused a highly significant (p > 0.05) reduction (p > 0.05) of all test enzymes tested compared to controls. The effects of different oil formulations exhibited time- and dose-dependent responses, resulting in physiological changes in the concentrations of various enzymes. The combined mixture of Tagetes erecta essential oils has significantly better anti-termite ability compared to inorganic insecticides. Findings from this study will help support termite control in fields, gardens and homes in a sustainable way, without the downsides of insecticide resistance and pollution. These could potentially be used to produce commercial formulations for use against pests.

Toxic Effects of Citrus maxima Based Combinatorial Formulations on Important Metabolic Enzymes in Indian White Termite Odontotermes obesus

In the present study, Citrus maxima essential crude oil extract was used to prepare combinatorial formulations and workers of Indian white termite Odontotermes obesus were treated topically with 40% and 80% of 24 hr LD50 values of these formulations. In subsequent bioassays levels of various enzymes i.e. alkaline phosphatase, acid phosphatase, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and acetylcholinesterase were evaluated to determine the anti-termite efficacy of Citrus maxima essential oil based combinatorial formulations. S-RET-A, S-RET-B and S-RET-C caused significant (p > 0.05) decrease in glutamate oxaloacetate transaminase i.e. 87.47%, 86.81% and 81.77% & 82.04%, 79.39% and 74.75% respectively at 16 h treatment. In vivo exposure of 40% and 80% of LD50 of combinatorial formulations caused very significant (p > 0.05) reduction in all the test enzymes i.e. alkaline phosphatase, acid phosphatase, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase expect acetylcholinesterase levels after 16 h all tested treatments in comparison to control. Both dose-response and time period were found important in physiological alteration in levels of various enzymes. Combinatorial mixtures of Citrus essential oils have shown synergistic activity against termites. The research findings of the present study would help termite control in crop fields, gardens and houses in a sustainable way.

Angiotensin-converting enzyme 2 alleviates liver fibrosis through the renin-angiotensin system

The present letter to the editor is related to the study titled‘Angiotensin-converting enzyme 2 improves liver fibrosis in mice by regulating autophagy of hepatic stellate cells’.Angiotensin-converting enzyme 2 can alleviate liver fibrosis by regulating autophagy of hepatic stellate cells and affecting the renin-angiotensin system.

Effect of Cellulose Enzymes on Some Properties of Fibre Clothes

This study examined the effects of the enzyme cellulose on a few single jersey and interlock 100% flax t-shirts, two different styles of knit children’s clothes that differ in both their chemical and mechanical characteristics. Clothing samples were dyed using reactive colours and then subjected to normal acid cellulose enzyme treatment procedures. We evaluated some physical and mechanical features before and after cellulose treatments, then compared these characteristics. Its cellulose enzymatic processing enhances some mechanical properties of fibre knitwear, such as pilling resistance and retention of water. Some characteristics of fibre-knitted clothing, such as fabric weight, fabric thickness, fabric burst resistance, and seam tensile strength of T-shirt side seams, are reduced by cellulose enzyme treatment at a manageable rate. Compared to single-jersey all-fiber children’s T-shirts, interlocking 100% flax children’s T-shirts have a better effect of the enzyme cellulose treatment on the majority of physical and mechanical attributes.

Enhanced production of cytidine 5'-monophosphate using biocatalysis of di-enzymes immobilized on amino-functionalized sepharose

Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for additives.In this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-cytidine kinase(UCK)and acetate kinase(AcK).The immobilization yield of the enzyme had a clear correlation with the surface charges as zeta potential(ξ).Among them,ε-polylysinefunctionalized sepharose(SA-EPL,ξ=9.31 m V)showed high immobilization yield(78.8%),which was4.9-fold than that of nitrilotriacetic acid functionalized sepharose(SA-NTA,ξ=-12.6 m V).The residual activity of affinity co-immobilized enzyme(EPL-Ni/EPL@Ac K-UCK)was higher than 70.6%after recycled 10 times.Thus,this study provides an effective approach for the production of 5'-CMP with the advantages of low adenosine 5'-triphosphate(ATP)consumption,reduced side reactions,and improved reusability by co-immobilized UCK and Ac K on the functionalized Sepharose.

Peptide self‐assembly as a strategy for facile immobilization of redox enzymes on carbon electrodes

Redox-enzyme‐mediated electrochemical processes such as hydrogen production,nitrogen fixation,and CO_(2) reduction are at the forefront of the green chemistry revolution.To scale up,the inefficient two‐dimensional(2D)immobilization of redox enzymes on working electrodes must be replaced by an efficient dense 3D system.Fabrication of 3D electrodes was demonstrated by embedding enzymes in polymer matrices.However,several requirements,such as simple immobilization,prolonged stability,and resistance to enzyme leakage,still need to be addressed.The study presented here aims to overcome these gaps by immobilizing enzymes in a supramolecular hydrogel formed by the self‐assembly of the peptide hydrogelator fluorenylmethyloxycarbonyldiphenylalanine.Harnessing the self‐assembly process avoids the need for tedious and potentially harmful chemistry,allowing the rapid loading of enzymes on a 3D electrode under mild conditions.Using the[FeFe]hydrogenase enzyme,high enzyme loads,prolonged resistance against electrophoresis,and highly efficient hydrogen production are demonstrated.Further,this enzyme retention is shown to arise from its interaction with the peptide nanofibrils.Finally,this method is successfully used to retain other redox enzymes,paving the way for a variety of enzyme‐mediated electrochemical applications.

Hepatic angiotensin-converting enzyme 2 expression in metabolic dysfunction-associated steatotic liver disease and in patients with fatal COVID-19

BACKGROUND Metabolic dysfunction-associated steatotic liver disease(MASLD),characterised by hepatic lipid accumulation,causes inflammation and oxidative stress accompanied by cell damage and fibrosis.Liver injury(LI)is also frequently reported in patients hospitalised with coronavirus disease 2019(COVID-19),while preexisting MASLD increases the risk of LI and the development of COVID-19-associated cholangiopathy.Mechanisms of injury at the cellular level remain unclear,but it may be significant that severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)which causes COVID-19,uses angiotensin-converting expression enzyme 2(ACE2),a key regulator of the‘anti-inflammatory’arm of the renin-angiotensin system,for viral attachment and host cell invasion.AIM To determine if hepatic ACE2 levels are altered during progression of MASLD and in patients who died with severe COVID-19.METHODS ACE2 protein levels and localisation,and histological fibrosis and lipid droplet accumulation as markers of MASLD were determined in formalin-fixed liver tissue sections across the MASLD pathological spectrum(isolated hepatocellular steatosis,metabolic dysfunction-associated steatohepatitis(MASH)+/-fibrosis,end-stage cirrhosis)and in post-mortem tissues from patients who had died with severe COVID-19,using ACE2 immunohistochemistry and haematoxylin and eosin and picrosirius red staining of total collagen and lipid droplet areas,followed by quantification using machine learning-based image pixel classifiers.RESULTS ACE2 staining is primarily intracellular and concentrated in the cytoplasm of centrilobular hepatocytes and apical membranes of bile duct cholangiocytes.Strikingly,ACE2 protein levels are elevated in non-fibrotic MASH compared to healthy controls but not in the progression to MASH with fibrosis and in cirrhosis.ACE2 protein levels and histological fibrosis are not associated,but ACE2 and liver lipid droplet content are significantly correlated across the MASLD spectrum.Hepatic ACE2 levels are also increased in COVID-19 patients,especially those showing evidence of LI,but are not correlated with the presence of SARS-CoV-2 virus in the liver.However,there is a clear association between the hepatic lipid droplet content and the presence of the virus,suggesting a possible functional link.CONCLUSION Hepatic ACE2 levels were elevated in nonfibrotic MASH and COVID-19 patients with LI,while lipid accumulation may promote intra-hepatic SARS-CoV-2 replication,accelerating MASLD progression and COVID-19-mediated liver damage.