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
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
Sesame is one of the eight major allergens that cause food allergies.Study of the epitopes of sesame allergens is important for understanding their sensitization mechanisms.Currently,less information is available on t...Sesame is one of the eight major allergens that cause food allergies.Study of the epitopes of sesame allergens is important for understanding their sensitization mechanisms.Currently,less information is available on the epitope studies of sesame allergens.In this study,we analyzed the molecular characteristics,structure and homology of Ses i 3,one of the important sesame allergens.We predicted the B-cell linear epitopes of Ses i 3 using bioinformatics tools and characterized them by slot blot immuno-microarrays technology.Eight peptides as B-cell linear epitopes of Ses i 3 were identified,in addition,key amino acids in these epitopes were predicted and leucine 422 was identified as a key amino acid.The present work will contribute to further understanding of the sesame allergen and provide some help in the prevention and treatment of sesame allergy.展开更多
The skeletal muscle is the largest organ present in the body and is responsible for mechanical activities like maintaining posture,movement,respiratory function,and support for the health and functioning of other syst...The skeletal muscle is the largest organ present in the body and is responsible for mechanical activities like maintaining posture,movement,respiratory function,and support for the health and functioning of other systems of the body.Skeletal muscle atrophy is a condition characterized by a reduction in muscle size,strength,and activity,which leads to an increased dependency on others for movement,an increased risk of falls,and a reduced quality of life.Various conditions like osteoarthritis,osteoporosis,and fractures are directly associated with increased muscle atrophy.Additionally,numerous risk factors,like aging,malnutrition,physical inactivity,and certain disease conditions,through distinct pathways,negatively affect skeletal muscle health and lead to muscle atrophy.Among various determinants of overall muscle health,the rate of muscle protein synthesis and degradation is an important parameter that eventually alters the fate of overall muscle health.In conditions of excessive skeletal muscle atrophy,including sarcopenia,the rate of muscle protein degradation usually exceeds the rate of protein synthesis.The availability of amino acids in the systemic circulation is a crucial step in muscle protein synthesis.The current review aims to consolidate the existing evidence on amino acids,highlight their mechanisms of action,and assess their roles and effectiveness in enhancing skeletal muscle health.展开更多
Although the parallel incorporation of fluorinated aromatic amino acids(FAAAs)into proteins has been explored since 2010,the corresponding ^(19)F NMR investigation has been lacking to date.To assess the potential of t...Although the parallel incorporation of fluorinated aromatic amino acids(FAAAs)into proteins has been explored since 2010,the corresponding ^(19)F NMR investigation has been lacking to date.To assess the potential of the parallel incorporation of FAAAs in studies of protein structure,dynamics and interactions,we examine the protein yields,fluorine incorporation efficiencies,and ^(19)F NMR spectra upon simultaneously incorporating FAAAs including 3-fluorotyrosine(3FY),4-fluorophenylalanine(4FF)and 5-fluorotryptophan(5FW)into two model proteins:the structured protein GB1 domain(GB1)and the intrinsically disordered protein a-synuclein(a-syn).We found that the simultaneous incorporation of 3FY and 5FW achieved higher efficiency than combinations of 4FF and 5FW,4FF and 3FY,or 3FY,4FF and 5FW.Moreover,incorporating more types of FAAAs leads to a reduction in overall yield.The ^(19)F spectra of 3FY,4FF and 5FW residues in α-syn and GB1 exhibited good dispersion of chemical shifts.However,the GB1 spectrum showed complexity due to incomplete fluorination and interactions within aromatic cluster.This complexity could be significantly reduced by supplementing the medium with natural aromatic amino acids.To validate the advantage of ^(19)F NMR spectrum,we use 3FY-4FF-5FW-F94W-α-syn to investigate the interaction between α-syn and sodium dodecyl sulphate(SDS)micelle.Our study demonstrates that ^(19)F NMR spectroscopy of proteins with parallel incorporation of FAAAs provides a valuable tool for investigating protein conformation,dynamics and interactions.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
Bioactive peptides have various excellent biological activities and serve as functional foods to prevent chronic diseases in the human body.This article investigated the regulatory effect of egg white peptides(EPs)on ...Bioactive peptides have various excellent biological activities and serve as functional foods to prevent chronic diseases in the human body.This article investigated the regulatory effect of egg white peptides(EPs)on the intestine barrier of young mice with colitis.The results showed that the intake of EPs could protect the intestines from inflammation damage.Besides,the expression of tight junction proteins and mucin is upregulated.Markedly,the intake of EPs can increase the concentration of amino acids in the serum of young mice,which is crucial for nutritional supplementation during intestinal inflammation process.Proteomics analysis implied that EPs can regulate protein expression in the intestine,involving multiple inflammatory pathways including phosphoinositide 3-kinase(PI3K)-protein kinase B(AKT)and mitogen-activated protein kinase(MAPK)signaling pathway.This demonstrated the health benefits of bioactive peptides and provides a theoretical basis for the development of animal derived proteins as functional foods.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
The tumor immune microenvironment(TIME)represents a complex battlefield where metabolic competition and immune evasion mechanisms converge to drive cancer progression.Amino acids,with their multifaceted biological rol...The tumor immune microenvironment(TIME)represents a complex battlefield where metabolic competition and immune evasion mechanisms converge to drive cancer progression.Amino acids,with their multifaceted biological roles,have emerged as pivotal regulators of tumor cell proliferation and immune cell functionality.The sensing mechanisms by which amino acids within the tumor microenvironment influence cellular growth,survival,and immune function are systematically explored in this review;the latest advances in understanding amino acid metabolism in tumor biology are also reviewed.In addition,the multifaceted roles of key amino acids in shaping the TIME with particular emphasis on tumor immunity and malignant growth were investigated.Finally,emerging therapeutic strategies targeting amino acid metabolism to reprogram the TIME are discussed,highlighting promising approaches,such as CAR-T cell therapy and engineered bacterial interventions.Through this comprehensive analysis,critical insights into future research directions and potential clinical translation of amino acid-targeted interventions are provided.展开更多
Temperature is well known as the major environmental factor that influences survival and growth of fish,which are poikilo-thermic animals.However,it is still unclear about the mechanism that underscores thermal-contro...Temperature is well known as the major environmental factor that influences survival and growth of fish,which are poikilo-thermic animals.However,it is still unclear about the mechanism that underscores thermal-controlled fish physiology,especially nutritional utilization and metabolism,which are vitally important in aquaculture.In the present study,juvenile turbot was force-fed with amino acid mixture and its postprandial absorption,nutrient sensing and metabolism under low(12,15℃),optimal(18℃)to high(21,24℃)temperatures were explored.Intestinal trypsin and lipase activity were highly sensitive to water temperature,and highest under optimal temperatures for turbot,whereas amylase remained constant.Selective groups of intestinal amino acid transporters were upregulated in cold temperatures,but the amino acid absorption capability was increased with rising temperature.The mechanistic target of rapamycin(mTOR)signaling pathway was most active at optimal temperature.Postprandial muscle protein deposition achieved maximum level under optimal temperature.Amino acid catabolic enzymes branched-chain aminotransferase and branched-chainα-keto acid dehydrogenase activities were increased with rising temperatures.High temperature increased significantly energy metabolism and stimulated cel-lular stress in liver.These findings highlight the critical role of temperature in modulating amino acid dynamics,metabolic processes and stress responses in juvenile turbot,providing valuable insights for optimizing aquaculture practices.展开更多
[Objective]The study aimed to investigate the effects of the amino acids of aspartate family on the biosynthesis of CoQ10 in Rhodpseudomonas palustris J001.[Method]The impacts of amino acids of this family on the bios...[Objective]The study aimed to investigate the effects of the amino acids of aspartate family on the biosynthesis of CoQ10 in Rhodpseudomonas palustris J001.[Method]The impacts of amino acids of this family on the biosynthesis of CoQ10 in Rhodopseudomnas palustris J001 were investigated by feeding these amino acids at the end of the logarithmic phase during incubation,which aim was for the optimization of the fermentation medium and genetic improvement of the strain for CoQ10 production.[Result]The results showed that feeding proper amount of methione(125 mg/L)could increase CoQ10 production by 20.2%,but feeding of lysine(above 500 mg/L),threonine(above 400 mg/L)and/or isoleucine(above 400 mg/L)repressed the biosynthesis of CoQ10.The results indicated that the aspartate kinase is subject to feedback inhibition or repression by lysine,threonine and isoleucine in the strain,which was unfavorable to the formation of methioine and then caused the decrease of CoQ10 production.[Conclusion]Lysine,threonine and isoleucine auxotrophic mutants with resistance to analogues of lysine,threonine and isoleucine could increase the production of CoQ10.展开更多
BACKGROUND： Under normal conditions, excitatory amino acids are dynamically balanced with inhibitory amino acids. Excitatory amino acids have been implicated in perinatal brain injury. OBJECTIVE： To investigate diff...BACKGROUND： Under normal conditions, excitatory amino acids are dynamically balanced with inhibitory amino acids. Excitatory amino acids have been implicated in perinatal brain injury. OBJECTIVE： To investigate differences in the levels of the excitatory amino acids glutamic acid and aspartic acid, and the inhibitory amino acid gamma-aminobutyric acid （GABA） in the cerebrospinal fluid （CSF） of children with spastic cerebral palsy or athetotic cerebral palsy. DESIGN, TIME AND SETTING： Case-control exploratory observation of neurotransmitter in patients. The experiment was performed in the Pediatrics Department of the Second Affiliated Hospital of Changsha Medical College, the Cerebral Palsy Center of Xiangtan Affiliated Hospital of South China University and the Pediatrics Department of Xiangya Hospital, between February 2006 and May 2007. PARTICIPANTS： We selected 27 children with cerebral palsy, including 13 with spastic cerebral palsy and 14 with athetotic cerebral palsy. We selected 10 patients who were not affected by any neurological disease as controls. METHODS： Two mL blood-free CSF was harvested between the third and fourth lumbar vertebrae of each patient after anesthesia, and stored at -70℃. One mL CSF was mixed with 10 mg sulfosalicylic acid and placed in ice-bath for 10 minutes, then centrifuged 2 000 g for 10 minutes. The supernatant was collected for amino acid quantitation. MAIN OUTCOME MEASURES： The concentrations of glutamic acid, aspartic acid and GABA in the CSF were determined by high-performance liquid chromatography and fluorometric method. The correlation of glutamic acid, aspartic acid and GABA levels with muscular tension in children with cerebral palsy was analyzed using linear dependence. RESULTS： The concentration of GABA was significantly lower in both spastic cerebral palsy and athetotic cerebral palsy patients than in the control group （P 〈 0.01）. Glutamic acid and aspartic acid were significantly higher in both cerebral palsy groups than in the control group （P 〈 0.05-0.01）. The concentration of GABA was significantly decreased in spastic cerebral palsy patients compared with the athetotic cerebral palsy group （P 〈 0.05）. Muscular tension was positively correlated with the concentration of glutamic acid in spastic cerebral palsy patients （P 〈 0.05） but there was no significant correlation between aspartic acid or GABA and muscular tension （P 〉 0.05）. CONCLUSION： Spastic cerebral palsy and athetotic cerebral palsy patients exhibit an imbalance of excitatory amino acids and inhibitory amino acids in their CSF： an increase in glutamic acid and aspartic acid, and a decrease in GABA. Amino acid levels are different in the CSF in varied types of cerebral palsy.展开更多
Increasing interests of difluorinated amino acids(DFAAs)have been raised in recent years due to their widespread bio-organic and medical applications.However,to date,only few investigations focused on their asymmetric...Increasing interests of difluorinated amino acids(DFAAs)have been raised in recent years due to their widespread bio-organic and medical applications.However,to date,only few investigations focused on their asymmetric synthesis.Exploring difluoromethyl reagent to tailor a novel pathway and developing efficient catalytic system are highly desirable for constructing structurally diverse chiral DFAAs.Herein,a copper-catalyzed asymmetric difluorobenzylation of aldimine esters is described.By usingα,α-difluorinated benzyltriflones as difluoromethyl reagents,this protocol allows the asymmetric synthesis ofα-quaternary DFAAs with wide scope,good yields and excellent enantioselectivities(90%-98%ee).Control experiments and DESI-MS analysis demonstrate the reaction probably proceeds via a key difluorocarbocation intermediate.Moreover,polyfluoroarenes are found efficient candidates to polyfluoroaryl amino acids via C-F activation.Gram-scale experiment,late-stage functionalization,synthesis of difluorinated dipeptides and bioactive molecular analogues revealed the utility of the protocol,thereby largely enriching the structural diversity of FAAs and providing more potential opportunities in drug discovery.展开更多
Nineteen L-N-2-hydroxyethylamino acids and L-N,N-bis(2-hydroxyethyl)amino acids were prepared from the reaction of chlorohydrin with L-alanine,L-valine,L-leucine,L-isoleucine,L- phenylalanine,L-serine,L-thrcunine,L-gl...Nineteen L-N-2-hydroxyethylamino acids and L-N,N-bis(2-hydroxyethyl)amino acids were prepared from the reaction of chlorohydrin with L-alanine,L-valine,L-leucine,L-isoleucine,L- phenylalanine,L-serine,L-thrcunine,L-glutamic acid,L-aspartic acid and glycine.L-N,N,N',N'-tetra (2-hydroxyethyl)cystine was prepared by the reaction of L-cystine with chlorohydrin.展开更多
Protein is quantitatively the most expensive nutrient in swine diets. Hence it is imperative to understand the physiological roles played by amino acids in growth, development, lactation, reproduction, and health of p...Protein is quantitatively the most expensive nutrient in swine diets. Hence it is imperative to understand the physiological roles played by amino acids in growth, development, lactation, reproduction, and health of pigs to improve their protein nutrition and reduce the costs of pork production. Due to incomplete knowledge of amino acid biochemistry and nutrition, it was traditionally assumed that neonatal, post-weaning, growing-finishing, and gestating pigs could synthesize sufficient amounts of all ＂nutritionally nonessential amino acids＂ （NEAA） to support maximum production performance. Therefore, over the past 50 years, much emphasis has been placed on dietary requirements of nutritionally essential amino acids as building blocks for tissue proteins. However, a large body of literature shows that NEAA, particularly glutamine, glutamate, arginine and proline regulate physiological functions via cell signaling pathways, such as mammalian target of rapamycin, AMP-activated protein kinase, extracellular signal-related kinase, Jun kinase, mitogen-activated protein kinase, and NEAA-derived gaseous molecules （e.g., nitric oxide, carbon monoxide, and hydrogen sulfide）. Available evidence shows that under current feeding programs, only 70% and 55% of dietary amino acids are deposited as tissue proteins in 14-day-old sow-reared piglets and in 30-day-old pigs weaned at 21 days of age, respectively. Therefore, there is an urgent need to understand the robes and dietary requirements of NEAA in swine nutrition. This review highlights the basic biochemistry and physiology of absorption and utilization of amino acids in young pigs to enhance the efficacy of utilization of dietary protein and to minimize excretion of nitrogenous wastes from the body.展开更多
A hydroponic experiment was carried out to determine the influence of replacing 20% of nitrate-N in nutrient solutions with 20 individual amino acids on growth, nitrate accumulation, and concentrations of nitrogen （N...A hydroponic experiment was carried out to determine the influence of replacing 20% of nitrate-N in nutrient solutions with 20 individual amino acids on growth, nitrate accumulation, and concentrations of nitrogen （N）, phosphorus （P）, and potassium （K） in pak-choi （Brassica chinensis L.） shoots. When 20% of nitrate-N was replaced with arginine （Arg） compared to the full nitrate treatment, pak-choi shoot fresh and dry weights increased significantly （P ≤ 0.05）, but when 20% of nitrate-N was replaced with alanine （Ala）, valine （Val）, leucine （Leu）, isoleucine （Ile）, proline （Pro）, phenylalanine （Phe）, methionine （Met）, aspartic acid （Asp）, glutamic acid （Glu）, lysine （Lys）, glycine （Gly）, serine （Ser）, threonine （Thr）, cysteine （Cys）, and tyrosine （Tyr）, shoot fresh and dry weights decreased significantly （P ≤ 0.05）. After replacing 20% of nitrate-N with asparagine （Asn） and glutamine （Gin）, shoot fresh and dry weights were unaffected. Compared to the full nitrate treatment, amino acid replacement treatments, except for Cys, Gly, histidine （His）, and Arg, significantly reduced （P ≤0.05） nitrate concentrations in plant shoots. Except for Cys, Leu, Pro, and Met, total N concentrations in plant tissues of the other amino acid treatments significantly increased （P ≤ 0.05）. Amino acids also affected total P and K concentrations, but the effects differed depending on individual amino acids. To improve pak-choi shoot quality, Gln and Asn, due to their insignificant effects on pak-choi growth, their significant reduction in nitrate concentrations, and their increase in macroelement content in plants, may be used to partially replace nitrate-N.展开更多
The intestine and the gut-associated lymphoid tissue（GALT） are essential components of whole body immune defense,protecting the body from foreign antigens and pathogens,while allowing tolerance to commensal bacteria...The intestine and the gut-associated lymphoid tissue（GALT） are essential components of whole body immune defense,protecting the body from foreign antigens and pathogens,while allowing tolerance to commensal bacteria and dietary antigens.The requirement for protein to support the immune system is well established.Less is known regarding the immune modifying properties of individual amino acids,particularly on the GALT.Both oral and parenteral feeding studies have established convincing evidence that not only the total protein intake,but the availability of specific dietary amino acids（in particular glutamine,glutamate,and arginine,and perhaps methionine,cysteine and threonine） are essential to optimizing the immune functions of the intestine and the proximal resident immune cells.These amino acids each have unique properties that include,maintaining the integrity,growth and function of the intestine,as well as normalizing inflammatory cytokine secretion and improving T-lymphocyte numbers,specific T cell functions,and the secretion of IgA by lamina propria cells.Our understanding of this area has come from studies that have supplemented single amino acids to a mixed protein diet and measuring the effect on specific immune parameters.Future studies should be designed using amino acid mixtures that target a number of specific functions of GALT in order to optimize immune function in domestic animals and humans during critical periods of development and various disease states.展开更多
Amino acids are essential plant compounds serving as the building blocks of proteins,the predominant forms of nitrogen(N)distribution,and signaling molecules.Plant amino acids derive from root acquisition,nitrate redu...Amino acids are essential plant compounds serving as the building blocks of proteins,the predominant forms of nitrogen(N)distribution,and signaling molecules.Plant amino acids derive from root acquisition,nitrate reduction,and ammonium assimilation.Many amino acid transporters(AATs)mediating transfer processes of amino acids have been functionally characterized in Arabidopsis,whereas the function and regulation of the vast majority of AATs in rice(Oryza sativa L.)and other crops remain unknown.In this review,we summarize the current understanding of amino acids in the rhizosphere and in metabolism.We describe their function as signal molecules and in regulating plant architecture,flowering time,and defense against abiotic stress and pathogen attack.AATs not only function in root acquisition and translocation of amino acids from source to sink organs,regulating N uptake and use efficiency,but also as transporters of non-amino acid substrates or as amino acid sensors.Several AAT genes show natural variations in their promoter and coding regions that are associated with altered uptake rate of amino acids,grain N content,and tiller number.Development of an amino acid transfer model in plants will advance the manipulation of AATs for improving rice architecture,grain yield and quality,and N-use efficiency.展开更多
The hydrolysis technology and reaction kinetics for amino acids production from fish proteins in subcritical water reactor without catalysts were investigated in a reactor with volume of 400 ml under the conditions of...The hydrolysis technology and reaction kinetics for amino acids production from fish proteins in subcritical water reactor without catalysts were investigated in a reactor with volume of 400 ml under the conditions of reaction temperature from 180-320℃, pressure from 5-26 MPa, and time from 5-60 rain. The quality and quantity of amino acids in hydrolysate were determined by bioLiquid chromatography, and 17 kinds of amino acids were obtained. For the important 8 amino acids, the experiments were conducted to examine the effects of reaction temperature, pressure and time on amino acids yield. The optimum conditions for high yield are obtained from the experimental results. It is found that the nitrogen and carbon dioxide atmosphere should be used for leucine, isoleucine and histidine production while the air atmosphere might be used for other amino acids. The reaction time of 30 rain and the experimental temperature of 220℃, 240℃ and 260℃ were adopted for reaction kinetic research. The total yield of amino acids versus reaction time have been examined experimentally. According to these experimental data and under the condition of water excess, the macroscopic reaction kinetic equation of fish proteins hydrolysis was obtained with the hydrolysis reaction order of 1.615 and the rate constants being 0.0017, 0.0045 and 0.0097 at 220℃, 240℃ and 260℃ respectively. The activation energy is 145.1 kJ·mol^- 1.展开更多
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supported by the Fundamental Research Funds for the Public Research Institutes of Chinese Academy of Inspection and Quarantine(2022JK04).
文摘Sesame is one of the eight major allergens that cause food allergies.Study of the epitopes of sesame allergens is important for understanding their sensitization mechanisms.Currently,less information is available on the epitope studies of sesame allergens.In this study,we analyzed the molecular characteristics,structure and homology of Ses i 3,one of the important sesame allergens.We predicted the B-cell linear epitopes of Ses i 3 using bioinformatics tools and characterized them by slot blot immuno-microarrays technology.Eight peptides as B-cell linear epitopes of Ses i 3 were identified,in addition,key amino acids in these epitopes were predicted and leucine 422 was identified as a key amino acid.The present work will contribute to further understanding of the sesame allergen and provide some help in the prevention and treatment of sesame allergy.
文摘The skeletal muscle is the largest organ present in the body and is responsible for mechanical activities like maintaining posture,movement,respiratory function,and support for the health and functioning of other systems of the body.Skeletal muscle atrophy is a condition characterized by a reduction in muscle size,strength,and activity,which leads to an increased dependency on others for movement,an increased risk of falls,and a reduced quality of life.Various conditions like osteoarthritis,osteoporosis,and fractures are directly associated with increased muscle atrophy.Additionally,numerous risk factors,like aging,malnutrition,physical inactivity,and certain disease conditions,through distinct pathways,negatively affect skeletal muscle health and lead to muscle atrophy.Among various determinants of overall muscle health,the rate of muscle protein synthesis and degradation is an important parameter that eventually alters the fate of overall muscle health.In conditions of excessive skeletal muscle atrophy,including sarcopenia,the rate of muscle protein degradation usually exceeds the rate of protein synthesis.The availability of amino acids in the systemic circulation is a crucial step in muscle protein synthesis.The current review aims to consolidate the existing evidence on amino acids,highlight their mechanisms of action,and assess their roles and effectiveness in enhancing skeletal muscle health.
基金supported by the Ministry of Science and Technology of China[grants 2021YFA1302602]the National Natural Science Foundation of China[grants 21925406,21991082,21921004]the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0540000 and YSBR-068).
文摘Although the parallel incorporation of fluorinated aromatic amino acids(FAAAs)into proteins has been explored since 2010,the corresponding ^(19)F NMR investigation has been lacking to date.To assess the potential of the parallel incorporation of FAAAs in studies of protein structure,dynamics and interactions,we examine the protein yields,fluorine incorporation efficiencies,and ^(19)F NMR spectra upon simultaneously incorporating FAAAs including 3-fluorotyrosine(3FY),4-fluorophenylalanine(4FF)and 5-fluorotryptophan(5FW)into two model proteins:the structured protein GB1 domain(GB1)and the intrinsically disordered protein a-synuclein(a-syn).We found that the simultaneous incorporation of 3FY and 5FW achieved higher efficiency than combinations of 4FF and 5FW,4FF and 3FY,or 3FY,4FF and 5FW.Moreover,incorporating more types of FAAAs leads to a reduction in overall yield.The ^(19)F spectra of 3FY,4FF and 5FW residues in α-syn and GB1 exhibited good dispersion of chemical shifts.However,the GB1 spectrum showed complexity due to incomplete fluorination and interactions within aromatic cluster.This complexity could be significantly reduced by supplementing the medium with natural aromatic amino acids.To validate the advantage of ^(19)F NMR spectrum,we use 3FY-4FF-5FW-F94W-α-syn to investigate the interaction between α-syn and sodium dodecyl sulphate(SDS)micelle.Our study demonstrates that ^(19)F NMR spectroscopy of proteins with parallel incorporation of FAAAs provides a valuable tool for investigating protein conformation,dynamics and interactions.
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.
基金funded by the National Natural Science Foundation of China(32272346)Graduate Innovation Fund of Jilin University.
文摘Bioactive peptides have various excellent biological activities and serve as functional foods to prevent chronic diseases in the human body.This article investigated the regulatory effect of egg white peptides(EPs)on the intestine barrier of young mice with colitis.The results showed that the intake of EPs could protect the intestines from inflammation damage.Besides,the expression of tight junction proteins and mucin is upregulated.Markedly,the intake of EPs can increase the concentration of amino acids in the serum of young mice,which is crucial for nutritional supplementation during intestinal inflammation process.Proteomics analysis implied that EPs can regulate protein expression in the intestine,involving multiple inflammatory pathways including phosphoinositide 3-kinase(PI3K)-protein kinase B(AKT)and mitogen-activated protein kinase(MAPK)signaling pathway.This demonstrated the health benefits of bioactive peptides and provides a theoretical basis for the development of animal derived proteins as functional foods.
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.
基金supported by grants from the National Key Research and Development Program of China(Grant No.2022YFC3401500 to P.W.Grant No.2021YFA1302200 to L.F.)+1 种基金the National Natural Science Foundation of China(Grant Nos.82341028 and 31920103007 to P.W.Grant Nos.82472815 and U24A20727 to L.F.)。
文摘The tumor immune microenvironment(TIME)represents a complex battlefield where metabolic competition and immune evasion mechanisms converge to drive cancer progression.Amino acids,with their multifaceted biological roles,have emerged as pivotal regulators of tumor cell proliferation and immune cell functionality.The sensing mechanisms by which amino acids within the tumor microenvironment influence cellular growth,survival,and immune function are systematically explored in this review;the latest advances in understanding amino acid metabolism in tumor biology are also reviewed.In addition,the multifaceted roles of key amino acids in shaping the TIME with particular emphasis on tumor immunity and malignant growth were investigated.Finally,emerging therapeutic strategies targeting amino acid metabolism to reprogram the TIME are discussed,highlighting promising approaches,such as CAR-T cell therapy and engineered bacterial interventions.Through this comprehensive analysis,critical insights into future research directions and potential clinical translation of amino acid-targeted interventions are provided.
基金supported by National Key R&D Program of China(grant 2023YFD2400600)National Natural Scientific Foundation of China(grant 32373147)China Agriculture Research System(grant CARS-47-G10).
文摘Temperature is well known as the major environmental factor that influences survival and growth of fish,which are poikilo-thermic animals.However,it is still unclear about the mechanism that underscores thermal-controlled fish physiology,especially nutritional utilization and metabolism,which are vitally important in aquaculture.In the present study,juvenile turbot was force-fed with amino acid mixture and its postprandial absorption,nutrient sensing and metabolism under low(12,15℃),optimal(18℃)to high(21,24℃)temperatures were explored.Intestinal trypsin and lipase activity were highly sensitive to water temperature,and highest under optimal temperatures for turbot,whereas amylase remained constant.Selective groups of intestinal amino acid transporters were upregulated in cold temperatures,but the amino acid absorption capability was increased with rising temperature.The mechanistic target of rapamycin(mTOR)signaling pathway was most active at optimal temperature.Postprandial muscle protein deposition achieved maximum level under optimal temperature.Amino acid catabolic enzymes branched-chain aminotransferase and branched-chainα-keto acid dehydrogenase activities were increased with rising temperatures.High temperature increased significantly energy metabolism and stimulated cel-lular stress in liver.These findings highlight the critical role of temperature in modulating amino acid dynamics,metabolic processes and stress responses in juvenile turbot,providing valuable insights for optimizing aquaculture practices.
文摘[Objective]The study aimed to investigate the effects of the amino acids of aspartate family on the biosynthesis of CoQ10 in Rhodpseudomonas palustris J001.[Method]The impacts of amino acids of this family on the biosynthesis of CoQ10 in Rhodopseudomnas palustris J001 were investigated by feeding these amino acids at the end of the logarithmic phase during incubation,which aim was for the optimization of the fermentation medium and genetic improvement of the strain for CoQ10 production.[Result]The results showed that feeding proper amount of methione(125 mg/L)could increase CoQ10 production by 20.2%,but feeding of lysine(above 500 mg/L),threonine(above 400 mg/L)and/or isoleucine(above 400 mg/L)repressed the biosynthesis of CoQ10.The results indicated that the aspartate kinase is subject to feedback inhibition or repression by lysine,threonine and isoleucine in the strain,which was unfavorable to the formation of methioine and then caused the decrease of CoQ10 production.[Conclusion]Lysine,threonine and isoleucine auxotrophic mutants with resistance to analogues of lysine,threonine and isoleucine could increase the production of CoQ10.
基金a grant from Health Department of Hunan Province,No.B2006-204
文摘BACKGROUND： Under normal conditions, excitatory amino acids are dynamically balanced with inhibitory amino acids. Excitatory amino acids have been implicated in perinatal brain injury. OBJECTIVE： To investigate differences in the levels of the excitatory amino acids glutamic acid and aspartic acid, and the inhibitory amino acid gamma-aminobutyric acid （GABA） in the cerebrospinal fluid （CSF） of children with spastic cerebral palsy or athetotic cerebral palsy. DESIGN, TIME AND SETTING： Case-control exploratory observation of neurotransmitter in patients. The experiment was performed in the Pediatrics Department of the Second Affiliated Hospital of Changsha Medical College, the Cerebral Palsy Center of Xiangtan Affiliated Hospital of South China University and the Pediatrics Department of Xiangya Hospital, between February 2006 and May 2007. PARTICIPANTS： We selected 27 children with cerebral palsy, including 13 with spastic cerebral palsy and 14 with athetotic cerebral palsy. We selected 10 patients who were not affected by any neurological disease as controls. METHODS： Two mL blood-free CSF was harvested between the third and fourth lumbar vertebrae of each patient after anesthesia, and stored at -70℃. One mL CSF was mixed with 10 mg sulfosalicylic acid and placed in ice-bath for 10 minutes, then centrifuged 2 000 g for 10 minutes. The supernatant was collected for amino acid quantitation. MAIN OUTCOME MEASURES： The concentrations of glutamic acid, aspartic acid and GABA in the CSF were determined by high-performance liquid chromatography and fluorometric method. The correlation of glutamic acid, aspartic acid and GABA levels with muscular tension in children with cerebral palsy was analyzed using linear dependence. RESULTS： The concentration of GABA was significantly lower in both spastic cerebral palsy and athetotic cerebral palsy patients than in the control group （P 〈 0.01）. Glutamic acid and aspartic acid were significantly higher in both cerebral palsy groups than in the control group （P 〈 0.05-0.01）. The concentration of GABA was significantly decreased in spastic cerebral palsy patients compared with the athetotic cerebral palsy group （P 〈 0.05）. Muscular tension was positively correlated with the concentration of glutamic acid in spastic cerebral palsy patients （P 〈 0.05） but there was no significant correlation between aspartic acid or GABA and muscular tension （P 〉 0.05）. CONCLUSION： Spastic cerebral palsy and athetotic cerebral palsy patients exhibit an imbalance of excitatory amino acids and inhibitory amino acids in their CSF： an increase in glutamic acid and aspartic acid, and a decrease in GABA. Amino acid levels are different in the CSF in varied types of cerebral palsy.
基金supported financially by the Youth Innovation Promotion Association CAS(No.2022375)National Nature Science Foundation of China(No.22171258)+1 种基金the Biological Resources Programme,Chinese Academy of Sciences(No.KFJ-BRP-008)the Sichuan Science and Technology Program(No.2022ZYD0038)。
文摘Increasing interests of difluorinated amino acids(DFAAs)have been raised in recent years due to their widespread bio-organic and medical applications.However,to date,only few investigations focused on their asymmetric synthesis.Exploring difluoromethyl reagent to tailor a novel pathway and developing efficient catalytic system are highly desirable for constructing structurally diverse chiral DFAAs.Herein,a copper-catalyzed asymmetric difluorobenzylation of aldimine esters is described.By usingα,α-difluorinated benzyltriflones as difluoromethyl reagents,this protocol allows the asymmetric synthesis ofα-quaternary DFAAs with wide scope,good yields and excellent enantioselectivities(90%-98%ee).Control experiments and DESI-MS analysis demonstrate the reaction probably proceeds via a key difluorocarbocation intermediate.Moreover,polyfluoroarenes are found efficient candidates to polyfluoroaryl amino acids via C-F activation.Gram-scale experiment,late-stage functionalization,synthesis of difluorinated dipeptides and bioactive molecular analogues revealed the utility of the protocol,thereby largely enriching the structural diversity of FAAs and providing more potential opportunities in drug discovery.
文摘Nineteen L-N-2-hydroxyethylamino acids and L-N,N-bis(2-hydroxyethyl)amino acids were prepared from the reaction of chlorohydrin with L-alanine,L-valine,L-leucine,L-isoleucine,L- phenylalanine,L-serine,L-thrcunine,L-glutamic acid,L-aspartic acid and glycine.L-N,N,N',N'-tetra (2-hydroxyethyl)cystine was prepared by the reaction of L-cystine with chlorohydrin.
基金supported by National Research Initiative Competitive Grants from the Animal Reproduction Program(2008-35203-19120)Animal Growth&Nutrient Utilization Program(2008-35206-18764)of the USDA National Institute of Food and Agriculture+6 种基金AHA(10GRNT4480020)Texas A&M AgriLife Research(H-8200)the National Basic Research Program of China(2013CB127302)the National Natural Science Foundation of China(30810103902,30972156,31172217,31272450,and 31272451)China Postdoctoral Science Foundation(2012T50163)Chinese Universities Scientific Funds(2012RC024)the Thousand-People Talent program at China Agricultural University
文摘Protein is quantitatively the most expensive nutrient in swine diets. Hence it is imperative to understand the physiological roles played by amino acids in growth, development, lactation, reproduction, and health of pigs to improve their protein nutrition and reduce the costs of pork production. Due to incomplete knowledge of amino acid biochemistry and nutrition, it was traditionally assumed that neonatal, post-weaning, growing-finishing, and gestating pigs could synthesize sufficient amounts of all ＂nutritionally nonessential amino acids＂ （NEAA） to support maximum production performance. Therefore, over the past 50 years, much emphasis has been placed on dietary requirements of nutritionally essential amino acids as building blocks for tissue proteins. However, a large body of literature shows that NEAA, particularly glutamine, glutamate, arginine and proline regulate physiological functions via cell signaling pathways, such as mammalian target of rapamycin, AMP-activated protein kinase, extracellular signal-related kinase, Jun kinase, mitogen-activated protein kinase, and NEAA-derived gaseous molecules （e.g., nitric oxide, carbon monoxide, and hydrogen sulfide）. Available evidence shows that under current feeding programs, only 70% and 55% of dietary amino acids are deposited as tissue proteins in 14-day-old sow-reared piglets and in 30-day-old pigs weaned at 21 days of age, respectively. Therefore, there is an urgent need to understand the robes and dietary requirements of NEAA in swine nutrition. This review highlights the basic biochemistry and physiology of absorption and utilization of amino acids in young pigs to enhance the efficacy of utilization of dietary protein and to minimize excretion of nitrogenous wastes from the body.
基金Project supported by the National Natural Science Foundation of China (No.30370838).
文摘A hydroponic experiment was carried out to determine the influence of replacing 20% of nitrate-N in nutrient solutions with 20 individual amino acids on growth, nitrate accumulation, and concentrations of nitrogen （N）, phosphorus （P）, and potassium （K） in pak-choi （Brassica chinensis L.） shoots. When 20% of nitrate-N was replaced with arginine （Arg） compared to the full nitrate treatment, pak-choi shoot fresh and dry weights increased significantly （P ≤ 0.05）, but when 20% of nitrate-N was replaced with alanine （Ala）, valine （Val）, leucine （Leu）, isoleucine （Ile）, proline （Pro）, phenylalanine （Phe）, methionine （Met）, aspartic acid （Asp）, glutamic acid （Glu）, lysine （Lys）, glycine （Gly）, serine （Ser）, threonine （Thr）, cysteine （Cys）, and tyrosine （Tyr）, shoot fresh and dry weights decreased significantly （P ≤ 0.05）. After replacing 20% of nitrate-N with asparagine （Asn） and glutamine （Gin）, shoot fresh and dry weights were unaffected. Compared to the full nitrate treatment, amino acid replacement treatments, except for Cys, Gly, histidine （His）, and Arg, significantly reduced （P ≤0.05） nitrate concentrations in plant shoots. Except for Cys, Leu, Pro, and Met, total N concentrations in plant tissues of the other amino acid treatments significantly increased （P ≤ 0.05）. Amino acids also affected total P and K concentrations, but the effects differed depending on individual amino acids. To improve pak-choi shoot quality, Gln and Asn, due to their insignificant effects on pak-choi growth, their significant reduction in nitrate concentrations, and their increase in macroelement content in plants, may be used to partially replace nitrate-N.
基金supported by CJ Field’s funding from the Natural Sciences and Engineering Council of Canada (NSERC)
文摘The intestine and the gut-associated lymphoid tissue（GALT） are essential components of whole body immune defense,protecting the body from foreign antigens and pathogens,while allowing tolerance to commensal bacteria and dietary antigens.The requirement for protein to support the immune system is well established.Less is known regarding the immune modifying properties of individual amino acids,particularly on the GALT.Both oral and parenteral feeding studies have established convincing evidence that not only the total protein intake,but the availability of specific dietary amino acids（in particular glutamine,glutamate,and arginine,and perhaps methionine,cysteine and threonine） are essential to optimizing the immune functions of the intestine and the proximal resident immune cells.These amino acids each have unique properties that include,maintaining the integrity,growth and function of the intestine,as well as normalizing inflammatory cytokine secretion and improving T-lymphocyte numbers,specific T cell functions,and the secretion of IgA by lamina propria cells.Our understanding of this area has come from studies that have supplemented single amino acids to a mixed protein diet and measuring the effect on specific immune parameters.Future studies should be designed using amino acid mixtures that target a number of specific functions of GALT in order to optimize immune function in domestic animals and humans during critical periods of development and various disease states.
基金supported by the National Natural Science Foundation of China(31930101)National Key Research and Development Program of China(2016YFD0100700)+1 种基金Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization and the Innovative Research Team Development Plan of the Ministry of Education of China(IRT17R56 and KYT201802)the Priority Academic Program Development from Jiangsu Government。
文摘Amino acids are essential plant compounds serving as the building blocks of proteins,the predominant forms of nitrogen(N)distribution,and signaling molecules.Plant amino acids derive from root acquisition,nitrate reduction,and ammonium assimilation.Many amino acid transporters(AATs)mediating transfer processes of amino acids have been functionally characterized in Arabidopsis,whereas the function and regulation of the vast majority of AATs in rice(Oryza sativa L.)and other crops remain unknown.In this review,we summarize the current understanding of amino acids in the rhizosphere and in metabolism.We describe their function as signal molecules and in regulating plant architecture,flowering time,and defense against abiotic stress and pathogen attack.AATs not only function in root acquisition and translocation of amino acids from source to sink organs,regulating N uptake and use efficiency,but also as transporters of non-amino acid substrates or as amino acid sensors.Several AAT genes show natural variations in their promoter and coding regions that are associated with altered uptake rate of amino acids,grain N content,and tiller number.Development of an amino acid transfer model in plants will advance the manipulation of AATs for improving rice architecture,grain yield and quality,and N-use efficiency.
基金Supported by the National Natural Science Foundation of China （50578091） and Shanghai Leading Academic Discipline Project （T-105）.
文摘The hydrolysis technology and reaction kinetics for amino acids production from fish proteins in subcritical water reactor without catalysts were investigated in a reactor with volume of 400 ml under the conditions of reaction temperature from 180-320℃, pressure from 5-26 MPa, and time from 5-60 rain. The quality and quantity of amino acids in hydrolysate were determined by bioLiquid chromatography, and 17 kinds of amino acids were obtained. For the important 8 amino acids, the experiments were conducted to examine the effects of reaction temperature, pressure and time on amino acids yield. The optimum conditions for high yield are obtained from the experimental results. It is found that the nitrogen and carbon dioxide atmosphere should be used for leucine, isoleucine and histidine production while the air atmosphere might be used for other amino acids. The reaction time of 30 rain and the experimental temperature of 220℃, 240℃ and 260℃ were adopted for reaction kinetic research. The total yield of amino acids versus reaction time have been examined experimentally. According to these experimental data and under the condition of water excess, the macroscopic reaction kinetic equation of fish proteins hydrolysis was obtained with the hydrolysis reaction order of 1.615 and the rate constants being 0.0017, 0.0045 and 0.0097 at 220℃, 240℃ and 260℃ respectively. The activation energy is 145.1 kJ·mol^- 1.
