Short-chain fatty acids,metabolites produced by the fermentation of dietary fiber by gut microbiota,have garnered significant attention due to their correlation with neurodegenerative diseases,particularly Parkinson’...Short-chain fatty acids,metabolites produced by the fermentation of dietary fiber by gut microbiota,have garnered significant attention due to their correlation with neurodegenerative diseases,particularly Parkinson’s disease.In this review,we summarize the changes in short-chain fatty acid levels and the abundance of short-chain fatty acid-producing bacteria in various samples from patients with Parkinson’s disease,highlighting the critical role of gut homeostasis imbalance in the pathogenesis and progression of the disease.Focusing on the nervous system,we discuss the molecular mechanisms by which short-chain fatty acids influence the homeostasis of both the enteric nervous system and the central nervous system.We identify key processes,including the activation of G protein-coupled receptors and the inhibition of histone deacetylases by short-chain fatty acids.Importantly,structural or functional disruptions in the enteric nervous system mediated by these fatty acids may lead to abnormalα-synuclein expression and gastrointestinal dysmotility,which could serve as an initiating event in Parkinson’s disease.Furthermore,we propose that short-chain fatty acids help establish communication between the enteric nervous system and the central nervous system via the vagal nerve,immune circulation,and endocrine signaling.This communication may shed light on their potential role in the transmission ofα-synuclein from the gut to the brain.Finally,we elucidate novel treatment strategies for Parkinson’s disease that target short-chain fatty acids and examine the challenges associated with translating short-chain fatty acid-based therapies into clinical practice.In conclusion,this review emphasizes the pivotal role of short-chain fatty acids in regulating gut-brain axis integrity and their significance in the pathogenesis of Parkinson’s disease from the perspective of the nervous system.Moreover,it highlights the potential value of short-chain fatty acids in early intervention for Parkinson’s disease.Future research into the molecular mechanisms of short-chain fatty acids and their synergistic interactions with other gut metabolites is likely to advance the clinical translation of innovative short-chain fatty acid-based therapies for Parkinson’s disease.展开更多
Preeclampsia(PE)poses a significant threat to maternal and fetal health,characterized by hypertension during pregnancy.This study investigates a promising approach to combat PE utilizing nanotechnology for the targete...Preeclampsia(PE)poses a significant threat to maternal and fetal health,characterized by hypertension during pregnancy.This study investigates a promising approach to combat PE utilizing nanotechnology for the targeted delivery of short-chain fatty acids.By leveraging a sol-gel method and chemical deposition,cerium oxide-coated mesoporous silica nanoparticles loaded with sodium butyrate(CeO_(2)@MSN@SB)were synthesized.The innovative strategy focuses on modulating gut microbiota and JunB proto-oncogene(JUNB)gene expression to induce macrophage M2 polarization and facilitate vascular remodeling.Evaluation in PE mouse models revealed that CeO_(2)@MSN@SB effectively improved blood pressure,urinary protein levels,placental function,and gut microbiota composition.Furthermore,the nanoparticles exhibited the ability to regulate key genes related to angiogenesis and inflammation,notably JUNB,leading to enhanced macrophage M2 polarization,trophoblast functionality,and vascular restructuring.These findings highlight that the application of nanotechnology holds potential to advance PE prevention and therapy.展开更多
Background During the transition period,cows are prone to negative energy balance,which can lead to a decline in production performance and health in severe cases.In recent years,it has been discovered that bile acids...Background During the transition period,cows are prone to negative energy balance,which can lead to a decline in production performance and health in severe cases.In recent years,it has been discovered that bile acids(BAs)can act not only as fat emulsifiers but also as signaling molecules to regulate body metabolism.Although BAs have been used to some extent in monogastric and aquatic animals,their role in ruminants,particularly in transition cows,remains unclear.Therefore,this study aimed to determine the effects of BAs on the production performance,milk and plasma fatty acid and BA composition,and fecal microbiota in transition dairy cows.Results Forty-six healthy transition Holstein dairy cows with similar conditions were randomly divided into two groups and supplemented with 0 or 20 g/d of BAs from 21 d before the expected calving to 21 d after calving.The production performance was tracked until 60 d after calving.The results indicated that BA supplementation significantly improved postpartum milk fat content and yields as well as the yields of unsaturated fatty acids,monounsaturated fatty acids,and polyunsaturated fatty acids in milk.There was a significant increase in the concentration of triglyceride and the proportion of C≤16 fatty acids in the plasma of cows supplemented with BAs,while the concentration of β-hydroxybutyrate and the proportion of C>16 fatty acids in the plasma decreased significantly.BA supplementation significantly altered the composition of the fecal bacterial community and increased the relative abundance of bacteria beneficial for BA metabolism and transformation(Romboutsia,Clostridium sensu_stricto_6,and Clostridium sensu_stricto_1).Functional prediction analysis showed that the relative abundance of bile salt hydrolase,7 α-hydroxysteroid dehydrogenase,and BA inducible E as well as the pathways related to BA metabolism also significantly increased in cows supplemented BAs.In addition,BA supplementation significantly altered the composition of plasma and fecal BAs,particularly increasing circulating secondary BA concentration,which might induce the complete oxidation of fatty acids in the liver and further reduce the concentration of β-hydroxybutyrate.Conclusions These findings highlight the potential benefits of BA supplementation in improving milk yields and quality,as well as influencing metabolic pathways in transition dairy cows.Meanwhile,further studies are needed to elucidate the underlying mechanisms and explore the broader implications of these results by using more tissue samples.展开更多
The sleep-wake cycle stands as an integrative process essential for sustaining optimal brain function and,either directly or indirectly,overall body health,encompassing metabolic and cardiovascular well-being.Given th...The sleep-wake cycle stands as an integrative process essential for sustaining optimal brain function and,either directly or indirectly,overall body health,encompassing metabolic and cardiovascular well-being.Given the heightened metabolic activity of the brain,there exists a considerable demand for nutrients in comparison to other organs.Among these,the branched-chain amino acids,comprising leucine,isoleucine,and valine,display distinctive significance,from their contribution to protein structure to their involvement in overall metabolism,especially in cerebral processes.Among the first amino acids that are released into circulation post-food intake,branched-chain amino acids assume a pivotal role in the regulation of protein synthesis,modulating insulin secretion and the amino acid sensing pathway of target of rapamycin.Branched-chain amino acids are key players in influencing the brain's uptake of monoamine precursors,competing for a shared transporter.Beyond their involvement in protein synthesis,these amino acids contribute to the metabolic cycles ofγ-aminobutyric acid and glutamate,as well as energy metabolism.Notably,they impact GABAergic neurons and the excitation/inhibition balance.The rhythmicity of branchedchain amino acids in plasma concentrations,observed over a 24-hour cycle and conserved in rodent models,is under circadian clock control.The mechanisms underlying those rhythms and the physiological consequences of their disruption are not fully understood.Disturbed sleep,obesity,diabetes,and cardiovascular diseases can elevate branched-chain amino acid concentrations or modify their oscillatory dynamics.The mechanisms driving these effects are currently the focal point of ongoing research efforts,since normalizing branched-chain amino acid levels has the ability to alleviate the severity of these pathologies.In this context,the Drosophila model,though underutilized,holds promise in shedding new light on these mechanisms.Initial findings indicate its potential to introduce novel concepts,particularly in elucidating the intricate connections between the circadian clock,sleep/wake,and metabolism.Consequently,the use and transport of branched-chain amino acids emerge as critical components and orchestrators in the web of interactions across multiple organs throughout the sleep/wake cycle.They could represent one of the so far elusive mechanisms connecting sleep patterns to metabolic and cardiovascular health,paving the way for potential therapeutic interventions.展开更多
The involvement of the excitatory amino acids glutamate and aspartate in ce rebral ischemia and excitotoxicity is well-documented.Nevertheless,the role of non-excitatory amino acids in brain damage following a stroke ...The involvement of the excitatory amino acids glutamate and aspartate in ce rebral ischemia and excitotoxicity is well-documented.Nevertheless,the role of non-excitatory amino acids in brain damage following a stroke or brain trauma remains largely understudied.The release of amino acids by necrotic cells in the ischemic core may contribute to the expansion of the penumbra.Our findings indicated that the reversible loss of field excitato ry postsynaptic potentials caused by transient hypoxia became irreversible when exposed to a mixture of just four non-excitatory amino acids(L-alanine,glycine,L-glutamine,and L-serine)at their plasma concentrations.These amino acids induce swelling in the somas of neurons and astrocytes during hypoxia,along with permanent dendritic damage mediated by N-methyl-D-aspartate receptors.Blocking N-methyl-D-aspartate receptors prevented neuronal damage in the presence of these amino acids during hypoxia.It is likely that astroglial swelling caused by the accumulation of these amino acids via the alanine-serine-cysteine transporter 2 exchanger and system N transporters activates volume-regulated anion channels,leading to the release of excitotoxins and subsequent neuronal damage through N-methyl-D-aspartate receptor activation.Thus,previously unrecognized mechanisms involving non-excitatory amino acids may contribute to the progression and expansion of brain injury in neurological emergencies such as stroke and traumatic brain injury.Understanding these pathways co uld highlight new therapeutic targets to mitigate brain injury.展开更多
Heterogeneous metal-catalyzed chemical conversions with a recyclable catalyst are very ideal and challenging for sustainable organic synthesis.A new bipyridyl-Mo(IV)-carbon nitride(CN-K/Mo-Bpy)was prepared by supporti...Heterogeneous metal-catalyzed chemical conversions with a recyclable catalyst are very ideal and challenging for sustainable organic synthesis.A new bipyridyl-Mo(IV)-carbon nitride(CN-K/Mo-Bpy)was prepared by supporting molybdenum complex on C_(3)N_(4)-K and characterized by FT-IR,XRD,SEM,XPS and ICP-OES.Heterogeneous CN–Mo-Bpy catalyst can be applied to the direct amination of nitroarenes and arylboronic acid,thus constructing various valuable diarylamines in high to excellent yields with a wide substrate scope and good functional group tolerance.It is worth noting that this heterogeneous catalyst has high chemical stability and can be recycled for at least five times without reducing its activity.展开更多
Morphology and growth rate of carbon dioxide hydrate on the interface between liquid carbon dioxide and humic acid solutions were studied in this work.It was found that after the growth of the hydrate film at the inte...Morphology and growth rate of carbon dioxide hydrate on the interface between liquid carbon dioxide and humic acid solutions were studied in this work.It was found that after the growth of the hydrate film at the interface,further growth of hydrate due to the suction of water in the capillary system formed between the wall of the cuvette and the end boundary of the hydrate layer occurs.Most probably,substantial effects on the formation of this capillary system may be caused by variations in reactor wall properties,for example,hydrophobic-hydrophilic balance,roughness,etc.We found,that the rate of CO_(2) hydrate film growth on the surface of the humic acid aqueous solution is 4-fold to lower in comparison with the growth rate on the surface of pure water.We suppose that this is caused by the adsorption of humic acid associates on the surface of hydrate particles and,as a consequence,by the deceleration of the diffusion of dissolved carbon dioxide to the growing hydrate particle.展开更多
Carbon dioxide(CO_(2))marine sequestration by hydrate method is considered as one of the options to effectively achieve carbon reduction.However,the slow rate of hydrate formation becomes a major limiting factor.In vi...Carbon dioxide(CO_(2))marine sequestration by hydrate method is considered as one of the options to effectively achieve carbon reduction.However,the slow rate of hydrate formation becomes a major limiting factor.In view of the gas-water mass transfer problem which is the main obstacle,this paper explored the amphiphilic amino acids to promote the formation of CO_(2)hydrate and used low-field nuclear magnetic resonance(LNMR)to conduct an innovative study on its kinetics and spatiotemporal distribution.By comparing the promotion performance of L-methionine(L-met),L-cysteine(L-cys),and L-valine(L-val),the comprehensive kinetic promotion ability of L-met was the highest,reducing the induction time by 60.0%,achieving the maximum water conversion of about 57.0%within only 1 h,and reaching a final CO_(2)storage efficiency of 84.6%.LNMR results showed that hydrates were preferentially formed in large and medium pores in the reservoir region.Interestingly,we found that the combined effect of hydrophilic groups and the hydrophobic side chain of L-met not only promoted the rearrangement of water molecules and provided more nucleation sites,but also created a localized CO_(2)supersaturated environment and facilitated gas-water redistribution.Meanwhile,L-met promoted the formation of a hydrate porous structure to ensure the continuous formation of hydrates.This study innovatively explored CO_(2)hydrate formation behavior in amphiphilic amino acids and laid a theoretical foundation for the realization of CO_(2)marine sequestration by hydrate method.展开更多
An efficient TfOH-catalyzed O—H insertion reaction of α-aryl diazoesters with carboxylic acids is reported.This metal-free protocol provides an operationally simple method for a one-pot assembly of diverse α-acylox...An efficient TfOH-catalyzed O—H insertion reaction of α-aryl diazoesters with carboxylic acids is reported.This metal-free protocol provides an operationally simple method for a one-pot assembly of diverse α-acyloxy esters in moderate to high yields with a broad substrate scope.All starting materials are readily available,and the reactions can be conducted in the open air at room temperature.展开更多
In this review, the carcass, meat quality, internal organs, basic nutrition component, amino acids （AAs）, fatty acids, inosine monophosphate （IMP） and mus- cle fiber of Tibetan swine were summarized for the first ...In this review, the carcass, meat quality, internal organs, basic nutrition component, amino acids （AAs）, fatty acids, inosine monophosphate （IMP） and mus- cle fiber of Tibetan swine were summarized for the first time. The formation mecha- nism of excellent features was analyzed from the aspects of physiological traits, ge- ographical environments and constraint reasons. Thereby, the outstanding features of Tibetan swine could be extended continuously, and the poor characteristics should be improved in the future.展开更多
BACKGROUND Barrett esophagus(BE),a metaplastic adaptive process to gastrointestinal reflux,is associated with a higher risk of developing esophageal adenocarcinoma.However,the factors and mechanism that drive the mali...BACKGROUND Barrett esophagus(BE),a metaplastic adaptive process to gastrointestinal reflux,is associated with a higher risk of developing esophageal adenocarcinoma.However,the factors and mechanism that drive the malignant progression of BE is not well understood.AIM To investigate the role of bile acids,a component of the reflux fluid,in the malignant progression of BE.METHODS Using engineered green fluorescent protein-labeled adult tissue-resident stem cells isolated from BE clinical biopsies(BE-ASCs)as the target,we studied the effect of hydrophobic deoxycholic acid(DCA)and hydrophilic tetrahydroxylated bile acids(THBA)on cell viability by fluorescence intensity analysis,mucin production by dark density measurement,tissue structure by pathology analysis,expression of different pro-inflammatory factors gene by quantitative polymerase chain reaction and proteins by Western blot.RESULTS We found that hydrophobic DCA has cytotoxic and proinflammatory effects through activation of interleukin-1β(IL-1β)-nuclear factor kappa-B(NF-κB)inflammatory pathway on BE-ASCs.This action results in impaired cell viability,tissue intactness,reduced mucin production,and increased transition to disorganized atypical cells without intestinal features.In contrast,co-culture with hydrophilic THBA inhibited the IL-1β-NF-κB inflammatory pathway with maintenance of mature intestinal type cellular and histomorphology.CONCLUSION Our data indicates that the hydrophilic bile acid THBA can counteract the cytotoxic and proinflammatory effect of hydrophobic DCA and prevent the malignant progression of BE by inhibiting the IL-1β-NF-κB pathway.展开更多
BACKGROUND Metabolic dysfunction-associated steatotic liver disease(MASLD)is the most common chronic liver disease worldwide.Its prevalence is closely linked to the dramatic rise in obesity and non-communicable diseas...BACKGROUND Metabolic dysfunction-associated steatotic liver disease(MASLD)is the most common chronic liver disease worldwide.Its prevalence is closely linked to the dramatic rise in obesity and non-communicable diseases.MASLD exhibits a progressive trajectory that may culminate in development of hepatic cirrhosis,thereby predisposing affected individuals to an elevated likelihood of hepatocarcinogenesis.Diet,especially dietary fatty acids,serves as a key link between nutrient intake and MASLD pathogenesis.AIM To explore the impact of various omega-6 fatty acid subtypes on the pathogenesis and therapeutic strategies of MASLD.METHODS A systematic literature search was conducted across Web of Science,PubMed,Cochrane Central,Scopus,and Embase databases from inception through June 2024 to identify all original studies linking different subtypes of omega-6 polyunsaturated fatty acids to the pathogenesis and management of MASLD.The search strategy explored the linkage between omega-6 polyunsaturated fatty acids and their subtypes,including linoleic acid(LA),gamma-linolenic acid(GLA),arachidonic acid,conjugated LA,and docosapentaenoic acid,in relation to MASLD and cardiometabolic risk.RESULTS By employing the specified search strategy,a total of 83 articles were identified as potentially eligible.During the title,abstract,and full-text screening phases,27 duplicate records were removed,leaving 56 records for relevance screening.Of these,43 records were excluded for reasons such as irrelevance and language restrictions(limited to English),resulting in 13 full-text articles being included for detailed assessment(10 human studies,1 animal study,and 2 review articles).Although certain subtypes,as GLA,dihomo-GLA,omega-6-derived oxylipins,and most arachidonic acid-derived eicosanoids,exhibit pro-inflammatory effects,our findings suggest that other subtypes such as LA,cis-9,trans-11 conjugated LA,and docosapentaenoic acid have beneficial effects on fatty liver,cardiometabolic risk factors,and inflammation,even at high intake levels.CONCLUSION The varying health effects of omega-6 fatty acids,ranging from anti-inflammatory to pro-inflammatory impacts on the liver,leave the question of their recommendation for MASLD patients unresolved.This underscores the importance of careful selection when considering omega-6 supplementation.展开更多
Alpha-linolenic acid(ALA)is capable of synthesizing eicosapentaenoic acid(EPA)and docosahexaenoic acid(DHA)in vivo,but the conversion rate is hard to meet the body's need for rapid DHA supplementation.Studies have...Alpha-linolenic acid(ALA)is capable of synthesizing eicosapentaenoic acid(EPA)and docosahexaenoic acid(DHA)in vivo,but the conversion rate is hard to meet the body's need for rapid DHA supplementation.Studies have shown that fucoxanthin can increase DHA content in the liver of mice,but the mechanism is not clear.Moreover,the effect of fucoxanthin and its metabolite fucoxanthinol on the chain lengthening reaction of n-6 polyunsaturated fatty acids(PUFAs)is little studied.In this study,the effects of fucoxanthin and fucoxanthinol on the chain elongation of n-3 and n-6 series PUFAs were investigated in mice.Results showed that fucoxanthin and fucoxanthinol significantly increased the conversion of n-3 series ALA to DHA and n-6 series linolenic acid(LA)to arachidonic acid(AA)in the serum,liver,small intestine,and heart of mice.In addition,fucoxanthin accelerated the rate of DHA supplementation by ALA in the brain.Further mechanistic studies revealed that the role of fucoxanthin in promoting PUFAs conversion was not regulated at transcriptional level,but by increasing the activity of fatty acid desaturase 2(FADS2),a key enzyme of chain elongation reaction of n-3 and n-6 PUFAs.This study fundamentally provided theoretical bases for a new strategy of dietary supplementation of n-3 and n-6 PUFAs.展开更多
The aim of the present study was to evaluate the effects of baobab seed washing and origin on the chemical composition of the oil extracted by pressing. Six (6) oil samples were obtained from seeds of three (3) geogra...The aim of the present study was to evaluate the effects of baobab seed washing and origin on the chemical composition of the oil extracted by pressing. Six (6) oil samples were obtained from seeds of three (3) geographical origins. The identification and quantification of fatty acids and the polyphenolic profile were carried out by GC-MS and HPLC-UV, respectively. Analysis of fatty acid methyl esters allowed the identification and quantification of 18 fatty acids. Oils from unwashed seeds were richer in palmitic (C16:0), stearic (C18:0), oleic (C18:1) and arachidic (C20:0) acids. In addition, HPLC-UV analysis at 279 nm shows that oils from unwashed seeds are richer in tyrosol, hydroxytyrosol and caffeic acid. With regard to the polyphenolic profile, gallic acid and quercetin were not detected in these baobab oils. Principal component analysis of fatty acid and phenolic compound content showed that oils from unwashed seeds would best preserve their chemical and associated potential bioactive characteristics.展开更多
Alduronic acid lactones and glyconolactones are highly functionalized and versatile chiral building blocks.Herein,we describe a novel approach to these compounds via decarboxylative oxygenation of uronic acids.The tra...Alduronic acid lactones and glyconolactones are highly functionalized and versatile chiral building blocks.Herein,we describe a novel approach to these compounds via decarboxylative oxygenation of uronic acids.The transformations proceed using Selectfluor and TEMPO as oxidants,either in the presence of catalytic amounts of Ag_(2)CO_(3)or in the absence of this catalyst.The methodology provides structurally diverse alduronic acid lactones and enables the preparation of rare sugar glyconolactones from easily available D-C-glycosides.Based on the^(18)O-labeling experiments,control experiments,and isolation of the key intermediates,a radical-polar crossover reaction mechanism is proposed.The utility of this method is demonstrated through efficient conversions of alduronic acid lactones into polyhydroxylated cyclic alkaloids and castanospermine-type architectures.展开更多
The anaerobic acid production experiments were conducted with the pretreated kitchen waste under pH adjustment.The results showed that pH 8 was considered to be the most suitable condition for acid production,especial...The anaerobic acid production experiments were conducted with the pretreated kitchen waste under pH adjustment.The results showed that pH 8 was considered to be the most suitable condition for acid production,especially for the formation of acetic acid and propionic acid.The average value of total volatile fatty acid at pH 8 was 8814 mg COD/L,1.5 times of that under blank condition.The average yield of acetic acid and propionic acid was 3302 mg COD/L and 2891 mg COD/L,respectively.The activities of key functional enzymes such as phosphotransacetylase,acetokinase,oxaloacetate transcarboxylase and succinylcoA transferase were all enhanced.To further explore the regulatory mechanisms within the system,the distribution of microorganisms at different levels in the fermentation system was obtained by microbial sequencing,results indicating that the relative abundances of Clostridiales,Bacteroidales,Chloroflexi,Clostridium,Bacteroidetes and Propionibacteriales,which were great contributors for the hydrolysis and acidification,increased rapidly at pH 8 compared with the blank group.Besides,the proportion of genes encoding key enzymes was generally increased,which further verified the mechanism of hydrolytic acidification and acetic acid production of organic matter under pH regulation.展开更多
Prolonged lack of rain and high-temperature lead to soil water deficits,inhibiting cereal crop growth in early ontogenesis and reducing grain quality and yield.Rye(Secale cereale L.)is a key grain crop,particularly in...Prolonged lack of rain and high-temperature lead to soil water deficits,inhibiting cereal crop growth in early ontogenesis and reducing grain quality and yield.Rye(Secale cereale L.)is a key grain crop,particularly in regions where wheat cultivation is challenging or unfeasible.To clarify its drought adaptation mechanisms,we analyzed the effects of moderate soil drought on growth,hormonal homeostasis,and the dynamics and distribution of free amino acids and phenolic compounds in rye at early vegetative stages and post-recovery.Drought triggered both general and organ-specific changes in endogenous phytohormones.A nonspecific response involved the accumulation of stress hormones abscisic acid(ABA)and salicylic acid(SA),alongside the suppression of growth hormones indole-3-acetic acid(IAA)and gibberellins.However,hormone dynamics and localization varied across plant organs.ABA and SA levels significantly increased in shoots of drought-stressed and recovered plants,corresponding with inhibited growth.Prolonged drought further enhanced ABA accumulation in both shoots and roots of recovered plants,while SA levels declined in roots but remained elevated in shoots.Drought also caused a substantial reduction in IAA,particularly in shoots,while gibberellins(GA_(3)+GA_(4))significantly decreased in roots.GA_(3)was predominant in most samples,except in the shoots of 2-day-old control plants.Post-recovery,IAA levels increased but remained below control values,while GA_(4)accumulation in roots led to a rise in total gibberellin levels.In contrast,shoot GA_(3)+GA_(4)levels declined,primarily due to GA_(3)reduction.The dominant free amino acids:aspartic acid,glutamic acid,glycine,alanine,and leucinedecreased significantly,underscoring their key role in stress adaptation.Increased flavonoid accumulation,especially in roots,suggests their involvement in antioxidant defense against oxidative stress.A significant increase in ABA and SA levels,along with a marked reduction in IAA and GA content in stressed rye plants occurred alongside a reduction in free amino acid content,accumulation of phenolic compounds,and an increase in flavonoid levels.These findings indicate distinct adaptation strategies in rye shoots and roots undermoderate soil drought.They provide a foundation for further research on drought resistance mechanisms in cereals and the development of strategies to enhance their adaptive potential.展开更多
Gallic acid(GA),a plant phenol ubiquitously present in fruits and vegetables,has demonstrated efficacy in ameliorating ulcerative colitis(UC).Despite previous reports,the precise mechanism of GA's therapeutic acti...Gallic acid(GA),a plant phenol ubiquitously present in fruits and vegetables,has demonstrated efficacy in ameliorating ulcerative colitis(UC).Despite previous reports,the precise mechanism of GA's therapeutic action remains elusive.Herein,the present study aims to delineate the mechanism underlying the anti-UC effects of GA by focusing on the interplay of gut microbiota,microbial and host cometabolites,and gut immune regulation.The findings revealed that GA treatment improved the colitis symptoms and systematic inflammatory response,reliant on gut microbiota,as evidenced by microbiota depletion and fecal microbiota transplantation.According to the 16S r DNA sequencing results,GA altered the gut microbiota community structure and upregulated the biosynthesis of secondary bile acids(SBAs).Metabolomics and flow cytometry(FCS)analysis revealed a substantial increase in SBAs production,including ursodeoxycholic acid(UDCA),lithocholic acid(LCA),3-oxo-lithocholic acid(3-oxo-LCA)and iso-allolithocholic acid(Isoallo LCA),which further upregulated the proportion of regulatory T(Treg)cells and downregulated the proportion of T helper type 17(Th17)cells in the colon,ultimately resulting in an improved Treg/Th17 balance.Further FCS and real-time quantitative PCR assays provided mechanistic insights,demonstrating that UDCA and Isoallo LCA facilitate Treg cell differentiation through the upregulation of nuclear hormone receptor 4A1(NR4A1).This research elucidated that GA effectively mitigates colitis by modulating the Treg/Th17 balance,facilitated by the enhanced synthesis of microbiota-derived SBAs.These insights unveil innovative pathways through which GA exerts its anti-UC effects,emphasizing the potential therapeutic benefits of incorporating a GAenriched diet into UC management.展开更多
Here,we report a novel nickel-catalyzed electrochemical carboxylation of propargylic esters with CO_(2),characterized by the regioselective synthesis of 2,3-allenoic acids rather than propargylic carboxylic acids.Both...Here,we report a novel nickel-catalyzed electrochemical carboxylation of propargylic esters with CO_(2),characterized by the regioselective synthesis of 2,3-allenoic acids rather than propargylic carboxylic acids.Both acyclic propargylic esters and cyclic propargylic carbonates serve as effective substrates,facilitating the synthesis of mono-,di-,tri-,and tetra-substituted 2,3-allenoic acids with broad substrate scope under mild conditions.Mechanistic investigations indicate that the in situ generated Ni(Ⅰ)complex might serve as the active species to react with propargylic esters,forming the allenyl-Ni(Ⅰ)complex under electroreductive conditions.A possible γ-selective nucleophilic attack of allenyl-Ni(Ⅰ)complex on CO_(2) is likely involved in the formation of the desired 2,3-allenoic acids.展开更多
The valorization of biomass to produce biofuels has become a heavily investigated field due to the depletion of fossil fuels and environmental concerns.Among them,the research on deoxygenation of fatty acids or esters...The valorization of biomass to produce biofuels has become a heavily investigated field due to the depletion of fossil fuels and environmental concerns.Among them,the research on deoxygenation of fatty acids or esters derived from biomass as well as municipal sludge organics to produce diesel-like hydrocarbons has become a hot topic.Fatty acid is a key intermediate derived from ester hydrolysis,therefore has attracted more attention as a model compound.In this review,we first introduce and compare the three reaction pathways of hydrodeoxygenation,decarboxylation and decarbonylation,for the deoxygenation of fatty acids and esters.The preference of reaction pathway is closely related to the type of raw materials and catalysts as well as reaction conditions.The special purpose of this review is to summarize the dilemma and possible strategies for deoxygenation of fatty acids,which is expected to provide guidance for future exploration and concentrates.The atom utilization along with stability during reaction in a long time is the most important index for commercial economy.Herein,we propose that the rational design and delicate synthesis of stable single-atom non-noble catalysts may be the best solution.The ultimately goal is aiming to develop sustainable production of green diesel hydrocarbons.展开更多
基金supported by the National Key R&D Program of China,No.2021YFC2501200(to PC).
文摘Short-chain fatty acids,metabolites produced by the fermentation of dietary fiber by gut microbiota,have garnered significant attention due to their correlation with neurodegenerative diseases,particularly Parkinson’s disease.In this review,we summarize the changes in short-chain fatty acid levels and the abundance of short-chain fatty acid-producing bacteria in various samples from patients with Parkinson’s disease,highlighting the critical role of gut homeostasis imbalance in the pathogenesis and progression of the disease.Focusing on the nervous system,we discuss the molecular mechanisms by which short-chain fatty acids influence the homeostasis of both the enteric nervous system and the central nervous system.We identify key processes,including the activation of G protein-coupled receptors and the inhibition of histone deacetylases by short-chain fatty acids.Importantly,structural or functional disruptions in the enteric nervous system mediated by these fatty acids may lead to abnormalα-synuclein expression and gastrointestinal dysmotility,which could serve as an initiating event in Parkinson’s disease.Furthermore,we propose that short-chain fatty acids help establish communication between the enteric nervous system and the central nervous system via the vagal nerve,immune circulation,and endocrine signaling.This communication may shed light on their potential role in the transmission ofα-synuclein from the gut to the brain.Finally,we elucidate novel treatment strategies for Parkinson’s disease that target short-chain fatty acids and examine the challenges associated with translating short-chain fatty acid-based therapies into clinical practice.In conclusion,this review emphasizes the pivotal role of short-chain fatty acids in regulating gut-brain axis integrity and their significance in the pathogenesis of Parkinson’s disease from the perspective of the nervous system.Moreover,it highlights the potential value of short-chain fatty acids in early intervention for Parkinson’s disease.Future research into the molecular mechanisms of short-chain fatty acids and their synergistic interactions with other gut metabolites is likely to advance the clinical translation of innovative short-chain fatty acid-based therapies for Parkinson’s disease.
基金supported by the 2025 National Health Commission Scientific Research Fund-Major Science and Technology Plan Project of Zhejiang Province(No:WKJ-ZJ-2533)the National Key Research and Development Program of China(No.SQ2022YFC2700013.2022YFC2704601).
文摘Preeclampsia(PE)poses a significant threat to maternal and fetal health,characterized by hypertension during pregnancy.This study investigates a promising approach to combat PE utilizing nanotechnology for the targeted delivery of short-chain fatty acids.By leveraging a sol-gel method and chemical deposition,cerium oxide-coated mesoporous silica nanoparticles loaded with sodium butyrate(CeO_(2)@MSN@SB)were synthesized.The innovative strategy focuses on modulating gut microbiota and JunB proto-oncogene(JUNB)gene expression to induce macrophage M2 polarization and facilitate vascular remodeling.Evaluation in PE mouse models revealed that CeO_(2)@MSN@SB effectively improved blood pressure,urinary protein levels,placental function,and gut microbiota composition.Furthermore,the nanoparticles exhibited the ability to regulate key genes related to angiogenesis and inflammation,notably JUNB,leading to enhanced macrophage M2 polarization,trophoblast functionality,and vascular restructuring.These findings highlight that the application of nanotechnology holds potential to advance PE prevention and therapy.
基金supported by the National Center of Technology Innovation for Dairy(No.2024-JSGG-021)the National Natural Science Foundation of China(No.32102570)the Key Research and Development Project of Ningxia(No.2024BBF01006).
文摘Background During the transition period,cows are prone to negative energy balance,which can lead to a decline in production performance and health in severe cases.In recent years,it has been discovered that bile acids(BAs)can act not only as fat emulsifiers but also as signaling molecules to regulate body metabolism.Although BAs have been used to some extent in monogastric and aquatic animals,their role in ruminants,particularly in transition cows,remains unclear.Therefore,this study aimed to determine the effects of BAs on the production performance,milk and plasma fatty acid and BA composition,and fecal microbiota in transition dairy cows.Results Forty-six healthy transition Holstein dairy cows with similar conditions were randomly divided into two groups and supplemented with 0 or 20 g/d of BAs from 21 d before the expected calving to 21 d after calving.The production performance was tracked until 60 d after calving.The results indicated that BA supplementation significantly improved postpartum milk fat content and yields as well as the yields of unsaturated fatty acids,monounsaturated fatty acids,and polyunsaturated fatty acids in milk.There was a significant increase in the concentration of triglyceride and the proportion of C≤16 fatty acids in the plasma of cows supplemented with BAs,while the concentration of β-hydroxybutyrate and the proportion of C>16 fatty acids in the plasma decreased significantly.BA supplementation significantly altered the composition of the fecal bacterial community and increased the relative abundance of bacteria beneficial for BA metabolism and transformation(Romboutsia,Clostridium sensu_stricto_6,and Clostridium sensu_stricto_1).Functional prediction analysis showed that the relative abundance of bile salt hydrolase,7 α-hydroxysteroid dehydrogenase,and BA inducible E as well as the pathways related to BA metabolism also significantly increased in cows supplemented BAs.In addition,BA supplementation significantly altered the composition of plasma and fecal BAs,particularly increasing circulating secondary BA concentration,which might induce the complete oxidation of fatty acids in the liver and further reduce the concentration of β-hydroxybutyrate.Conclusions These findings highlight the potential benefits of BA supplementation in improving milk yields and quality,as well as influencing metabolic pathways in transition dairy cows.Meanwhile,further studies are needed to elucidate the underlying mechanisms and explore the broader implications of these results by using more tissue samples.
基金supported by a grant from the French Society of Sleep Research and Medicine(to LS)The China Scholarship Council(to HL)The CNRS,INSERM,Claude Bernard University Lyon1(to LS)。
文摘The sleep-wake cycle stands as an integrative process essential for sustaining optimal brain function and,either directly or indirectly,overall body health,encompassing metabolic and cardiovascular well-being.Given the heightened metabolic activity of the brain,there exists a considerable demand for nutrients in comparison to other organs.Among these,the branched-chain amino acids,comprising leucine,isoleucine,and valine,display distinctive significance,from their contribution to protein structure to their involvement in overall metabolism,especially in cerebral processes.Among the first amino acids that are released into circulation post-food intake,branched-chain amino acids assume a pivotal role in the regulation of protein synthesis,modulating insulin secretion and the amino acid sensing pathway of target of rapamycin.Branched-chain amino acids are key players in influencing the brain's uptake of monoamine precursors,competing for a shared transporter.Beyond their involvement in protein synthesis,these amino acids contribute to the metabolic cycles ofγ-aminobutyric acid and glutamate,as well as energy metabolism.Notably,they impact GABAergic neurons and the excitation/inhibition balance.The rhythmicity of branchedchain amino acids in plasma concentrations,observed over a 24-hour cycle and conserved in rodent models,is under circadian clock control.The mechanisms underlying those rhythms and the physiological consequences of their disruption are not fully understood.Disturbed sleep,obesity,diabetes,and cardiovascular diseases can elevate branched-chain amino acid concentrations or modify their oscillatory dynamics.The mechanisms driving these effects are currently the focal point of ongoing research efforts,since normalizing branched-chain amino acid levels has the ability to alleviate the severity of these pathologies.In this context,the Drosophila model,though underutilized,holds promise in shedding new light on these mechanisms.Initial findings indicate its potential to introduce novel concepts,particularly in elucidating the intricate connections between the circadian clock,sleep/wake,and metabolism.Consequently,the use and transport of branched-chain amino acids emerge as critical components and orchestrators in the web of interactions across multiple organs throughout the sleep/wake cycle.They could represent one of the so far elusive mechanisms connecting sleep patterns to metabolic and cardiovascular health,paving the way for potential therapeutic interventions.
基金supported by MICIU(grant number PID2021-128133NB-100/AEI/FEDER10.13039/501100011033 to JMHG)by the National Institutes of Health(grant number R01 NS083858 to SAK)+1 种基金the Intramural Grants Program IGPP00057(to SAK)VIC enjoys a FPU contract from the Comunidad de Madrid(PIPF-2022/SAL-GL-25948)。
文摘The involvement of the excitatory amino acids glutamate and aspartate in ce rebral ischemia and excitotoxicity is well-documented.Nevertheless,the role of non-excitatory amino acids in brain damage following a stroke or brain trauma remains largely understudied.The release of amino acids by necrotic cells in the ischemic core may contribute to the expansion of the penumbra.Our findings indicated that the reversible loss of field excitato ry postsynaptic potentials caused by transient hypoxia became irreversible when exposed to a mixture of just four non-excitatory amino acids(L-alanine,glycine,L-glutamine,and L-serine)at their plasma concentrations.These amino acids induce swelling in the somas of neurons and astrocytes during hypoxia,along with permanent dendritic damage mediated by N-methyl-D-aspartate receptors.Blocking N-methyl-D-aspartate receptors prevented neuronal damage in the presence of these amino acids during hypoxia.It is likely that astroglial swelling caused by the accumulation of these amino acids via the alanine-serine-cysteine transporter 2 exchanger and system N transporters activates volume-regulated anion channels,leading to the release of excitotoxins and subsequent neuronal damage through N-methyl-D-aspartate receptor activation.Thus,previously unrecognized mechanisms involving non-excitatory amino acids may contribute to the progression and expansion of brain injury in neurological emergencies such as stroke and traumatic brain injury.Understanding these pathways co uld highlight new therapeutic targets to mitigate brain injury.
基金support for this work by Hebei Education Department(No.JZX2024004)Central Guidance on Local Science and Technology Development Fund of Hebei Province(No.236Z1404G)+3 种基金the National Natural Science Foundation of China(Nos.22301060 and 21272053)China Postdoctoral Science Foundation(No.2023M730914)the Natural Science Foundation of Hebei Province(Biopharmaceutical Joint Fund No.B2022206008)Project of Science and Technology Department of Hebei Province(No.22567622H)。
文摘Heterogeneous metal-catalyzed chemical conversions with a recyclable catalyst are very ideal and challenging for sustainable organic synthesis.A new bipyridyl-Mo(IV)-carbon nitride(CN-K/Mo-Bpy)was prepared by supporting molybdenum complex on C_(3)N_(4)-K and characterized by FT-IR,XRD,SEM,XPS and ICP-OES.Heterogeneous CN–Mo-Bpy catalyst can be applied to the direct amination of nitroarenes and arylboronic acid,thus constructing various valuable diarylamines in high to excellent yields with a wide substrate scope and good functional group tolerance.It is worth noting that this heterogeneous catalyst has high chemical stability and can be recycled for at least five times without reducing its activity.
基金supported by the Russian Science Foundation(23-29-00830).
文摘Morphology and growth rate of carbon dioxide hydrate on the interface between liquid carbon dioxide and humic acid solutions were studied in this work.It was found that after the growth of the hydrate film at the interface,further growth of hydrate due to the suction of water in the capillary system formed between the wall of the cuvette and the end boundary of the hydrate layer occurs.Most probably,substantial effects on the formation of this capillary system may be caused by variations in reactor wall properties,for example,hydrophobic-hydrophilic balance,roughness,etc.We found,that the rate of CO_(2) hydrate film growth on the surface of the humic acid aqueous solution is 4-fold to lower in comparison with the growth rate on the surface of pure water.We suppose that this is caused by the adsorption of humic acid associates on the surface of hydrate particles and,as a consequence,by the deceleration of the diffusion of dissolved carbon dioxide to the growing hydrate particle.
基金supported by the National Key Research and Development Program of China for Young Scientists(Grant No.2023YFB4104100)the National Natural Science Foundation of China(Grant 52176057)+3 种基金the National Key Research and Development Program of China(Grant No.2023YFB4104201)supported by the Unveiling and Commanding Foundation of Liaoning Province(Grant 2023JH1/10400003)the Shenzhen Science and Technology Program(No.JCYJ20220818095605012)supported by the Young Changjiang Scholars programme of China。
文摘Carbon dioxide(CO_(2))marine sequestration by hydrate method is considered as one of the options to effectively achieve carbon reduction.However,the slow rate of hydrate formation becomes a major limiting factor.In view of the gas-water mass transfer problem which is the main obstacle,this paper explored the amphiphilic amino acids to promote the formation of CO_(2)hydrate and used low-field nuclear magnetic resonance(LNMR)to conduct an innovative study on its kinetics and spatiotemporal distribution.By comparing the promotion performance of L-methionine(L-met),L-cysteine(L-cys),and L-valine(L-val),the comprehensive kinetic promotion ability of L-met was the highest,reducing the induction time by 60.0%,achieving the maximum water conversion of about 57.0%within only 1 h,and reaching a final CO_(2)storage efficiency of 84.6%.LNMR results showed that hydrates were preferentially formed in large and medium pores in the reservoir region.Interestingly,we found that the combined effect of hydrophilic groups and the hydrophobic side chain of L-met not only promoted the rearrangement of water molecules and provided more nucleation sites,but also created a localized CO_(2)supersaturated environment and facilitated gas-water redistribution.Meanwhile,L-met promoted the formation of a hydrate porous structure to ensure the continuous formation of hydrates.This study innovatively explored CO_(2)hydrate formation behavior in amphiphilic amino acids and laid a theoretical foundation for the realization of CO_(2)marine sequestration by hydrate method.
文摘An efficient TfOH-catalyzed O—H insertion reaction of α-aryl diazoesters with carboxylic acids is reported.This metal-free protocol provides an operationally simple method for a one-pot assembly of diverse α-acyloxy esters in moderate to high yields with a broad substrate scope.All starting materials are readily available,and the reactions can be conducted in the open air at room temperature.
基金Supported by National Science and Technology Support Program"Integration and Demonstration of Security Technology for Production-Ecosystem-Life in Key Pastoral Areas"(2012BAD13B00)National Science and Technology Support Program"In-tegration and Demonstration of Optimized Security Technology for Production-Ecosystem-Life in the Pastoral Area of Northwest Sichuan"(2012BAD13B06)~~
文摘In this review, the carcass, meat quality, internal organs, basic nutrition component, amino acids （AAs）, fatty acids, inosine monophosphate （IMP） and mus- cle fiber of Tibetan swine were summarized for the first time. The formation mecha- nism of excellent features was analyzed from the aspects of physiological traits, ge- ographical environments and constraint reasons. Thereby, the outstanding features of Tibetan swine could be extended continuously, and the poor characteristics should be improved in the future.
文摘BACKGROUND Barrett esophagus(BE),a metaplastic adaptive process to gastrointestinal reflux,is associated with a higher risk of developing esophageal adenocarcinoma.However,the factors and mechanism that drive the malignant progression of BE is not well understood.AIM To investigate the role of bile acids,a component of the reflux fluid,in the malignant progression of BE.METHODS Using engineered green fluorescent protein-labeled adult tissue-resident stem cells isolated from BE clinical biopsies(BE-ASCs)as the target,we studied the effect of hydrophobic deoxycholic acid(DCA)and hydrophilic tetrahydroxylated bile acids(THBA)on cell viability by fluorescence intensity analysis,mucin production by dark density measurement,tissue structure by pathology analysis,expression of different pro-inflammatory factors gene by quantitative polymerase chain reaction and proteins by Western blot.RESULTS We found that hydrophobic DCA has cytotoxic and proinflammatory effects through activation of interleukin-1β(IL-1β)-nuclear factor kappa-B(NF-κB)inflammatory pathway on BE-ASCs.This action results in impaired cell viability,tissue intactness,reduced mucin production,and increased transition to disorganized atypical cells without intestinal features.In contrast,co-culture with hydrophilic THBA inhibited the IL-1β-NF-κB inflammatory pathway with maintenance of mature intestinal type cellular and histomorphology.CONCLUSION Our data indicates that the hydrophilic bile acid THBA can counteract the cytotoxic and proinflammatory effect of hydrophobic DCA and prevent the malignant progression of BE by inhibiting the IL-1β-NF-κB pathway.
文摘BACKGROUND Metabolic dysfunction-associated steatotic liver disease(MASLD)is the most common chronic liver disease worldwide.Its prevalence is closely linked to the dramatic rise in obesity and non-communicable diseases.MASLD exhibits a progressive trajectory that may culminate in development of hepatic cirrhosis,thereby predisposing affected individuals to an elevated likelihood of hepatocarcinogenesis.Diet,especially dietary fatty acids,serves as a key link between nutrient intake and MASLD pathogenesis.AIM To explore the impact of various omega-6 fatty acid subtypes on the pathogenesis and therapeutic strategies of MASLD.METHODS A systematic literature search was conducted across Web of Science,PubMed,Cochrane Central,Scopus,and Embase databases from inception through June 2024 to identify all original studies linking different subtypes of omega-6 polyunsaturated fatty acids to the pathogenesis and management of MASLD.The search strategy explored the linkage between omega-6 polyunsaturated fatty acids and their subtypes,including linoleic acid(LA),gamma-linolenic acid(GLA),arachidonic acid,conjugated LA,and docosapentaenoic acid,in relation to MASLD and cardiometabolic risk.RESULTS By employing the specified search strategy,a total of 83 articles were identified as potentially eligible.During the title,abstract,and full-text screening phases,27 duplicate records were removed,leaving 56 records for relevance screening.Of these,43 records were excluded for reasons such as irrelevance and language restrictions(limited to English),resulting in 13 full-text articles being included for detailed assessment(10 human studies,1 animal study,and 2 review articles).Although certain subtypes,as GLA,dihomo-GLA,omega-6-derived oxylipins,and most arachidonic acid-derived eicosanoids,exhibit pro-inflammatory effects,our findings suggest that other subtypes such as LA,cis-9,trans-11 conjugated LA,and docosapentaenoic acid have beneficial effects on fatty liver,cardiometabolic risk factors,and inflammation,even at high intake levels.CONCLUSION The varying health effects of omega-6 fatty acids,ranging from anti-inflammatory to pro-inflammatory impacts on the liver,leave the question of their recommendation for MASLD patients unresolved.This underscores the importance of careful selection when considering omega-6 supplementation.
基金supported by Qingdao Marine Science and Technology Center(2022QNLM030003-1)Taishan Scholars Program(tstp20240812)+3 种基金Youth Innovation Team Program of Universities in Shandong Province(2023KJ040)Open Foundation of State Key Laboratory of Marine Food Processing&Safety Control(SKL202412)China Postdoctoral Science Foundation(2024M763107)Postdoctoral Fellowship Program of CPSF(GZC20241617)。
文摘Alpha-linolenic acid(ALA)is capable of synthesizing eicosapentaenoic acid(EPA)and docosahexaenoic acid(DHA)in vivo,but the conversion rate is hard to meet the body's need for rapid DHA supplementation.Studies have shown that fucoxanthin can increase DHA content in the liver of mice,but the mechanism is not clear.Moreover,the effect of fucoxanthin and its metabolite fucoxanthinol on the chain lengthening reaction of n-6 polyunsaturated fatty acids(PUFAs)is little studied.In this study,the effects of fucoxanthin and fucoxanthinol on the chain elongation of n-3 and n-6 series PUFAs were investigated in mice.Results showed that fucoxanthin and fucoxanthinol significantly increased the conversion of n-3 series ALA to DHA and n-6 series linolenic acid(LA)to arachidonic acid(AA)in the serum,liver,small intestine,and heart of mice.In addition,fucoxanthin accelerated the rate of DHA supplementation by ALA in the brain.Further mechanistic studies revealed that the role of fucoxanthin in promoting PUFAs conversion was not regulated at transcriptional level,but by increasing the activity of fatty acid desaturase 2(FADS2),a key enzyme of chain elongation reaction of n-3 and n-6 PUFAs.This study fundamentally provided theoretical bases for a new strategy of dietary supplementation of n-3 and n-6 PUFAs.
文摘The aim of the present study was to evaluate the effects of baobab seed washing and origin on the chemical composition of the oil extracted by pressing. Six (6) oil samples were obtained from seeds of three (3) geographical origins. The identification and quantification of fatty acids and the polyphenolic profile were carried out by GC-MS and HPLC-UV, respectively. Analysis of fatty acid methyl esters allowed the identification and quantification of 18 fatty acids. Oils from unwashed seeds were richer in palmitic (C16:0), stearic (C18:0), oleic (C18:1) and arachidic (C20:0) acids. In addition, HPLC-UV analysis at 279 nm shows that oils from unwashed seeds are richer in tyrosol, hydroxytyrosol and caffeic acid. With regard to the polyphenolic profile, gallic acid and quercetin were not detected in these baobab oils. Principal component analysis of fatty acid and phenolic compound content showed that oils from unwashed seeds would best preserve their chemical and associated potential bioactive characteristics.
基金financial support from the Marine S&T Fund of Shandong Province for Qingdao Marine Science and Technology Center(No.2022QNLM030003-2)the National Key Research&Development Program of China(No.2022YFA2104902)the National Natural Science Foundation of China(Nos.21977088 and22377114)。
文摘Alduronic acid lactones and glyconolactones are highly functionalized and versatile chiral building blocks.Herein,we describe a novel approach to these compounds via decarboxylative oxygenation of uronic acids.The transformations proceed using Selectfluor and TEMPO as oxidants,either in the presence of catalytic amounts of Ag_(2)CO_(3)or in the absence of this catalyst.The methodology provides structurally diverse alduronic acid lactones and enables the preparation of rare sugar glyconolactones from easily available D-C-glycosides.Based on the^(18)O-labeling experiments,control experiments,and isolation of the key intermediates,a radical-polar crossover reaction mechanism is proposed.The utility of this method is demonstrated through efficient conversions of alduronic acid lactones into polyhydroxylated cyclic alkaloids and castanospermine-type architectures.
基金supported by the National Key Research and Development Program of China(No.2019YFC1906304).
文摘The anaerobic acid production experiments were conducted with the pretreated kitchen waste under pH adjustment.The results showed that pH 8 was considered to be the most suitable condition for acid production,especially for the formation of acetic acid and propionic acid.The average value of total volatile fatty acid at pH 8 was 8814 mg COD/L,1.5 times of that under blank condition.The average yield of acetic acid and propionic acid was 3302 mg COD/L and 2891 mg COD/L,respectively.The activities of key functional enzymes such as phosphotransacetylase,acetokinase,oxaloacetate transcarboxylase and succinylcoA transferase were all enhanced.To further explore the regulatory mechanisms within the system,the distribution of microorganisms at different levels in the fermentation system was obtained by microbial sequencing,results indicating that the relative abundances of Clostridiales,Bacteroidales,Chloroflexi,Clostridium,Bacteroidetes and Propionibacteriales,which were great contributors for the hydrolysis and acidification,increased rapidly at pH 8 compared with the blank group.Besides,the proportion of genes encoding key enzymes was generally increased,which further verified the mechanism of hydrolytic acidification and acetic acid production of organic matter under pH regulation.
基金This publication presents findings from research conducted under Project No.III-99-24.489Natural Growth Regulators in the Induction of Resistance of Cereal Plants to HeavyMetals(2024-2028)funded by the NationalAcademy of Sciences of Ukraine.
文摘Prolonged lack of rain and high-temperature lead to soil water deficits,inhibiting cereal crop growth in early ontogenesis and reducing grain quality and yield.Rye(Secale cereale L.)is a key grain crop,particularly in regions where wheat cultivation is challenging or unfeasible.To clarify its drought adaptation mechanisms,we analyzed the effects of moderate soil drought on growth,hormonal homeostasis,and the dynamics and distribution of free amino acids and phenolic compounds in rye at early vegetative stages and post-recovery.Drought triggered both general and organ-specific changes in endogenous phytohormones.A nonspecific response involved the accumulation of stress hormones abscisic acid(ABA)and salicylic acid(SA),alongside the suppression of growth hormones indole-3-acetic acid(IAA)and gibberellins.However,hormone dynamics and localization varied across plant organs.ABA and SA levels significantly increased in shoots of drought-stressed and recovered plants,corresponding with inhibited growth.Prolonged drought further enhanced ABA accumulation in both shoots and roots of recovered plants,while SA levels declined in roots but remained elevated in shoots.Drought also caused a substantial reduction in IAA,particularly in shoots,while gibberellins(GA_(3)+GA_(4))significantly decreased in roots.GA_(3)was predominant in most samples,except in the shoots of 2-day-old control plants.Post-recovery,IAA levels increased but remained below control values,while GA_(4)accumulation in roots led to a rise in total gibberellin levels.In contrast,shoot GA_(3)+GA_(4)levels declined,primarily due to GA_(3)reduction.The dominant free amino acids:aspartic acid,glutamic acid,glycine,alanine,and leucinedecreased significantly,underscoring their key role in stress adaptation.Increased flavonoid accumulation,especially in roots,suggests their involvement in antioxidant defense against oxidative stress.A significant increase in ABA and SA levels,along with a marked reduction in IAA and GA content in stressed rye plants occurred alongside a reduction in free amino acid content,accumulation of phenolic compounds,and an increase in flavonoid levels.These findings indicate distinct adaptation strategies in rye shoots and roots undermoderate soil drought.They provide a foundation for further research on drought resistance mechanisms in cereals and the development of strategies to enhance their adaptive potential.
基金funded by the National Natural Science Foundation of China(82174104 and 22104158)Guangzhou Science and Technology Program(2023B03J1382)+2 种基金Nansha Science and Technology Program(2022ZD004)Science and Technology Innovation Strategy of Guangdong Province(2020A1111350001)Natural Science Foundation of Hunan Province(2021JJ40041)。
文摘Gallic acid(GA),a plant phenol ubiquitously present in fruits and vegetables,has demonstrated efficacy in ameliorating ulcerative colitis(UC).Despite previous reports,the precise mechanism of GA's therapeutic action remains elusive.Herein,the present study aims to delineate the mechanism underlying the anti-UC effects of GA by focusing on the interplay of gut microbiota,microbial and host cometabolites,and gut immune regulation.The findings revealed that GA treatment improved the colitis symptoms and systematic inflammatory response,reliant on gut microbiota,as evidenced by microbiota depletion and fecal microbiota transplantation.According to the 16S r DNA sequencing results,GA altered the gut microbiota community structure and upregulated the biosynthesis of secondary bile acids(SBAs).Metabolomics and flow cytometry(FCS)analysis revealed a substantial increase in SBAs production,including ursodeoxycholic acid(UDCA),lithocholic acid(LCA),3-oxo-lithocholic acid(3-oxo-LCA)and iso-allolithocholic acid(Isoallo LCA),which further upregulated the proportion of regulatory T(Treg)cells and downregulated the proportion of T helper type 17(Th17)cells in the colon,ultimately resulting in an improved Treg/Th17 balance.Further FCS and real-time quantitative PCR assays provided mechanistic insights,demonstrating that UDCA and Isoallo LCA facilitate Treg cell differentiation through the upregulation of nuclear hormone receptor 4A1(NR4A1).This research elucidated that GA effectively mitigates colitis by modulating the Treg/Th17 balance,facilitated by the enhanced synthesis of microbiota-derived SBAs.These insights unveil innovative pathways through which GA exerts its anti-UC effects,emphasizing the potential therapeutic benefits of incorporating a GAenriched diet into UC management.
基金financial support from the National Natural Science Foundation of China(Nos.22171090,21871090)National Key Research and Development Program of China(No.2020YFA0710200)+1 种基金the Innovation Program of Shanghai Municipal Education Commission(No.2023ZKZD37)the Fundamental Research Funds for the Central Universities are highly appreciated。
文摘Here,we report a novel nickel-catalyzed electrochemical carboxylation of propargylic esters with CO_(2),characterized by the regioselective synthesis of 2,3-allenoic acids rather than propargylic carboxylic acids.Both acyclic propargylic esters and cyclic propargylic carbonates serve as effective substrates,facilitating the synthesis of mono-,di-,tri-,and tetra-substituted 2,3-allenoic acids with broad substrate scope under mild conditions.Mechanistic investigations indicate that the in situ generated Ni(Ⅰ)complex might serve as the active species to react with propargylic esters,forming the allenyl-Ni(Ⅰ)complex under electroreductive conditions.A possible γ-selective nucleophilic attack of allenyl-Ni(Ⅰ)complex on CO_(2) is likely involved in the formation of the desired 2,3-allenoic acids.
基金supported by the National Key R&D Program of China (No. 2021YFE0104900)Guangdong Basic and Applied Basic Research Foundation (No. 2023A1515030018)
文摘The valorization of biomass to produce biofuels has become a heavily investigated field due to the depletion of fossil fuels and environmental concerns.Among them,the research on deoxygenation of fatty acids or esters derived from biomass as well as municipal sludge organics to produce diesel-like hydrocarbons has become a hot topic.Fatty acid is a key intermediate derived from ester hydrolysis,therefore has attracted more attention as a model compound.In this review,we first introduce and compare the three reaction pathways of hydrodeoxygenation,decarboxylation and decarbonylation,for the deoxygenation of fatty acids and esters.The preference of reaction pathway is closely related to the type of raw materials and catalysts as well as reaction conditions.The special purpose of this review is to summarize the dilemma and possible strategies for deoxygenation of fatty acids,which is expected to provide guidance for future exploration and concentrates.The atom utilization along with stability during reaction in a long time is the most important index for commercial economy.Herein,we propose that the rational design and delicate synthesis of stable single-atom non-noble catalysts may be the best solution.The ultimately goal is aiming to develop sustainable production of green diesel hydrocarbons.
