Two-dimensional nanofluidic membranes have garnered considerable interest due to their potential for cost-effective osmotic energy harvesting.One promising approach to enhancing ion conductivity and selectivity is the...Two-dimensional nanofluidic membranes have garnered considerable interest due to their potential for cost-effective osmotic energy harvesting.One promising approach to enhancing ion conductivity and selectivity is the incorporation of vip additives.However,the traditional host-vip configuration can undermine the structural integrity of nanochannels owing to the inconsistent size and shape of these additives.Drawing inspiration from the intricate design of biological protein channels,which utilize small amino acid molecules as vips,we have addressed this issue by incorporating glycine,a common amino acid,into a vermiculite membrane using a simple vacuum-assisted infiltration method.The resulting vermiculite-glycine membrane demonstrates 1.8 times greater ionic conductivity and twice the power density compared to pure vermiculite membranes.Analysis based on glycine content,coupled with spectroscopic examination,reveals that ion conductivity is linked to the distribution of glycine molecules across three specific sites within the membrane.This suggests that glycine molecules—whether confined in voids,adsorbed onto nanochannel surfaces,or intercalated within multilayered vermiculite nanoparticles—enhance nanofluidic ion transport by modulating surface and space charge density,as well as strengthening hydrogen bonding,electrostatic interactions,and steric effects.This work reveals the specific interactions between amino acids and vermiculite,offering a novel path for advancing nanofluidic composite membranes and highlighting critical considerations for the proposed strategy.展开更多
CR Dhan 310(CRD310),a biofortified rice variety,contains a significantly higher level of grain protein compared with its recurrent parent Naveen(NV),as well as most adapted high-yielding rice varieties in India.Althou...CR Dhan 310(CRD310),a biofortified rice variety,contains a significantly higher level of grain protein compared with its recurrent parent Naveen(NV),as well as most adapted high-yielding rice varieties in India.Although a limited investigation depicted that CRD310 contained higher levels of glutelin and some essential amino acids,detailed biochemical,molecular,and cellular mechanisms remain to be studied.As one of the means to identify the proteins and understand the underlying mechanism of higher proteins accumulation in grains of CRD310,the comparative proteomics was undertaken on grains of CRD310 and NV at the yellow ripening stage.展开更多
Peptides play important roles in chemistry,medicinal chemistry and life science,due to their high efficiency and specificity,unusual biological and therapeutic properties.As naturally occurring peptides often face wit...Peptides play important roles in chemistry,medicinal chemistry and life science,due to their high efficiency and specificity,unusual biological and therapeutic properties.As naturally occurring peptides often face with their intrinsic limitations including metabolic instability and low membrane permeability,the strategies for synthesizing unnatural amino acids and peptides are explored.Among the methods for modifying amino acids and peptides,chemo-and site-selective approaches are preferred because of the ability to fine-tuning structural features.Recently,transition metal-catalyzed Csingle bondH activation has been employed for the functionalization of amino acids and peptides.Through domino Csingle bondH activation/annulation,a series of structurally complex and diverse amino acids and peptides is constructed.This review highlights recent advances in the synthesis of unnatural amino acids and peptides via transition metal-catalyzed Csingle bondH activation/annulation.展开更多
Metabolic reprogramming involving branched-chain amino acids(BCAAs)—leucine,isoleucine,and valine—is increasingly recognized as pivotal in cancer progression,metastasis,and immune modulation.This review comprehensiv...Metabolic reprogramming involving branched-chain amino acids(BCAAs)—leucine,isoleucine,and valine—is increasingly recognized as pivotal in cancer progression,metastasis,and immune modulation.This review comprehensively explores how cancer cells rewire BCAA metabolism to enhance proliferation,survival,and therapy resistance.Tumors manipulate BCAA uptake and catabolism via high expression of transporters like L-type amino acid transporter 1(LAT1)and enzymes including branched chain amino acid transaminase 1(BCAT1),branched chain amino acid transaminase 2(BCAT2),branched-chain alpha-keto acid dehydrogenase(BCKDH),and branched chain alpha-keto acid dehydrogenase kinase(BCKDK).These alterations sustain energy production,biosynthesis,redox homeostasis,and oncogenic signaling(especially mammalian target of rapamycin complex 1[mTORC1]).Crucially,tumor-driven BCAA depletion also shapes an immunosuppressive microenvironment,impairing anti-tumor immunity by limiting essential nutrients for T cells and natural killer(NK)cells.Innovative therapeutic strategies targeting BCAA pathways—ranging from selective small-molecule inhibitors(e.g.,LAT1 and BCAT1/2)to dietary modulation—have shown promising preclinical and early clinical efficacy,highlighting their potential to exploit metabolic vulnerabilities in cancer cells while bolstering immune responses.By integrating multi-omics data and precision targeting approaches,this review underscores the translational significance of BCAA metabolic reprogramming,positioning it as a novel frontier in cancer treatment.展开更多
Chiral amino acids(AAs)serve as essential building blocks of proteins and play vital physiological roles in living organisms.To achieve accurate,rapid,and high-throughput analysis of chiral AAs,this work proposed a me...Chiral amino acids(AAs)serve as essential building blocks of proteins and play vital physiological roles in living organisms.To achieve accurate,rapid,and high-throughput analysis of chiral AAs,this work proposed a methylbenzyl isocyanate(MBIC)derivatization strategy coupled with ultra-high performance liquid chromatography-mass spectrometry or trapped ion mobility spectrometry-mass spectrometry.The integration of a chiral carbon atom with a rigid urea-based structure can significantly enhance the separation of chiral MBIC-labeled AA enantiomers.This phenomenon can be attributed to the labeled l-AAs allow the carboxyl group to form intramolecular hydrogen bonds with the amino group in the rigid urea-based structure,whereas labeled d-AAs are unable to form such bonds.The method based on MBIC derivatization coupled with ultra-performance liquid chromatography-tandem mass spectrometry achieved simultaneous separation of 19 pairs of chiral AAs using only a C18 column within 30 min,enabling quantitatively detect twelve types of chiral AAs in the serum of healthy humans and Parkinson's patients.The distribution of twenty-four chiral AAs is observed in mouse brain using MBIC labeling-based matrix-assisted laser desorption/ionization-trapped ion mobility spectrometry-mass spectrometry imaging without prior separation.Our work elucidates the principles governing the separation of chiral AAs using derivatization methods,providing valuable guidance for the separation of chiral compounds.展开更多
Skeletal muscle accounts for approximately 40%of body mass and 50%–75%of whole-body protein,playing a central role in meat production and quality.Efficient protein synthesis in skeletal muscle relies on an adequate s...Skeletal muscle accounts for approximately 40%of body mass and 50%–75%of whole-body protein,playing a central role in meat production and quality.Efficient protein synthesis in skeletal muscle relies on an adequate supply of nutrient substrates and a balanced amino acid profile.Branched-chain amino acids(BCAA),including leucine(Leu),isoleucine(Ile),and valine(Val),are the most abundant essential amino acids in skeletal muscle and contribute to both protein synthesis and oxidative energy production.Additionally,BCAA function as signaling molecules that regulate gene expression and protein phosphorylation cascades,which significantly influence physiological processes,such as protein synthesis and degradation,glucose and lipid metabolism,and cell apoptosis and autophagy.These processes are primarily mediated through the PI3K/AKT/AMPK/mTOR signaling pathways.This review summarizes BCAA transporters and catabolic metabolism,their role as signaling molecules in regulating protein metabolism and glucose and lipid equilibrium,and applications in animal production.These findings offer both theoretical insights and practical guidelines for the precise regulation of feed efficiency and production performance through tailored dietary BCAA supplementations.展开更多
The detection of amino acid enantiomers holds significant importance in biomedical,chemical,food,and other fields.Traditional chiral recognition methods using fluorescent probes primarily rely on fluorescence intensit...The detection of amino acid enantiomers holds significant importance in biomedical,chemical,food,and other fields.Traditional chiral recognition methods using fluorescent probes primarily rely on fluorescence intensity changes,which can compromise accuracy and repeatability.In this study,we report a novel fluorescent probe(R)-Z1 that achieves effective enantioselective recognition of chiral amino acids in water by altering emission wavelengths(>60 nm).This water-soluble probe(R)-Z1 exhibits cyan or yellow-green luminescence upon interaction with amino acid enantiomers,enabling reliable chiral detection of 14 natural amino acids.It also allows for the determination of enantiomeric excess through monitoring changes in luminescent color.Additionally,a logic operation with two inputs and three outputs was constructed based on these optical properties.Notably,amino acid enantiomers were successfully detected via dual-channel analysis at both the food and cellular levels.This study provides a new dynamic luminescence-based tool for the accurate sensing and detection of amino acid enantiomers.展开更多
Post-exercise whey protein isolate(WPI)supplement is beneficial for skeletal muscle recovery due to the stimulation of branched chain amino acids(BCAAs).This implies us that intake slow digestion rate of protein to su...Post-exercise whey protein isolate(WPI)supplement is beneficial for skeletal muscle recovery due to the stimulation of branched chain amino acids(BCAAs).This implies us that intake slow digestion rate of protein to sustain BCAAs releasing rate may facilitate muscle protein synthesis.To examine this hypothesis,we conducted a series of protein supplements including modified slow-digesting whey(SDW),whey,hydrolyzed whey and casein,orally to mice undergoing endurance running.Our results showed that the SDW gavage constant supplied BCAAs in the serum of mice within 6 h and significantly enhanced(P<0.01)endurance exercise capacity,compared to other groups.In addition,the SDW supplementation increased the crosssectional area of mice gastrocnemius fibers,as well as their muscle and liver glycogen content.It also increased the testosterone/cortisol ratio in serum and interleukin-6(IL-6)levels in muscle,while it decreased the tumor necrosis factor-alpha(TNF-α)levels and oxidative stress in muscle.Moreover,it may activate mechanistic target of rapamycin signaling by upregulating mRNA(bcat-1 and pgc-1α)expression.Thus,our findings illustrate that prolonged BCAAs supply duration promotes mice endurance running capacity and skeletal muscle growth,contributing to the advancement of sports nutrition practices.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
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
The amino acid contents of five floral sources Chinese honeys(jujube, rape, chaste, acacia, and lungan) were measured using reversed phase high-performance liquid chromatography(RP-HPLC). The results showed that proli...The amino acid contents of five floral sources Chinese honeys(jujube, rape, chaste, acacia, and lungan) were measured using reversed phase high-performance liquid chromatography(RP-HPLC). The results showed that proline was the main amino acid in most of the analyzed samples. Phenylalanine presents at the highest content in chaste honey samples, and the total amino acid contents of chaste honeys were also significantly higher than those of other honey samples. Based on the amino acid contents, honey samples were classified using chemometric methods(cluster analysis(CA), principal component analysis(PCA), and discriminant analysis(DA)). According to the CA results, chaste honeys could be separated from other honeys, while the remaining samples were correctly grouped together when the chaste honey data were excluded. By using DA, the overall correct classification rate reached 100%. The results revealed that amino acid contents could potentially be used as indicators to identify the botanical origin of unifloral honeys.展开更多
Free amino acid(FAA)is the important component of vinegar that infl uences quality perception and consumer acceptance.FAA is one of the major metabolites produced by microorganisms;however,the microbial metabolic netw...Free amino acid(FAA)is the important component of vinegar that infl uences quality perception and consumer acceptance.FAA is one of the major metabolites produced by microorganisms;however,the microbial metabolic network on FAA biosynthesis remains unclear.Through metagenomic analysis,this work aimed to elucidate the roles of microbes in FAA biosynthesis during Monascus rice vinegar fermentation.Taxonomic profiles from functional analyses showed 14 dominant genera with high contributions to the metabolism pathways.The metabolic network for FAA biosynthesis was then constructed,and the microbial distribution in different metabolic pathways was illuminated.The results revealed that 5 functional genera were closely involved in FAA biosynthesis.This study illuminated the metabolic roles of microorganisms in FAA biosynthesis and provided crucial insights into the functional attributes of microbiota in vinegar fermentation.展开更多
Background： The current study was carried out to determine effects of dietary protein source and crude protein（CP）level on carcass characteristics, meat quality, and muscle amino acid（AA） profile in finishing gil...Background： The current study was carried out to determine effects of dietary protein source and crude protein（CP）level on carcass characteristics, meat quality, and muscle amino acid（AA） profile in finishing gilts. The experiment was designed as a 2 × 2 factorial arrangement with two sources of dietary proteins（cottonseed meal, CSM vs. soybean meal, SBM） and two levels of CP（12 % vs. 14 %, as-fed basis）. Seventy-two crossbred gilts（89.5 ± 0.9 kg） were allotted to one of four dietary treatments in a randomized complete block design for a period of 28 d. All diets were formulated to be isoenergetic and similar concentrations of standardized ileal digestible essential AA covering the nutrient requirements of pigs.Results： Growth, carcass characteristics and meat quality were not affected by dietary protein source nor crude protein level（P ＆gt; 0.10） except that average daily feed intake was increased by CSM diets（P = 0.03）. Gilts offered reduced protein diets had lower muscle p H45min（P 〈 0.05）. Neither dietary protein source nor crude protein level influenced N deposition. However, reduced protein diets decreased N intake, N excretion, and serum urea nitrogen content, whilst improved N efficiency（P 〈 0.01）. CSM diets increased N intake（P = 0.04）,but did not depress N efficiency. The concentrations of phenylalanine, tryptophan, cysteine and tyrosine（P 〈 0.05） of the longissimus muscle were decreased when gilts offered CSM diets, while muscle intracellular free valine concentration was increased（P = 0.03）. The gilts offered reduced protein diets had greater intracellular concentrations of free methionine, lysine, and total AA in muscle（P 〈 0.05）.Conclusion： These results suggest that CSM could replace SBM as a primary protein source in finishing pig diets in terms of performance, N efficiency, carcass characteristics, and meat quality, but decrease the concentrations of muscle specific AA. Furthermore, the reduced protein diet played an important role in increasing muscle intracellular concentrations of specific free amino acids（FAA）, and in reducing the relative ratios of specific FAA to lysine in longissimus dorsi muscle of pig, whose biological meaning needs further studies.展开更多
The protective effect and mechanism of diazepam on ischemia neurons during cerebral ischemia and reperfusion were studied. Sixty three Wistar rats were divided randomly into nine groups: control group , ischemia gro...The protective effect and mechanism of diazepam on ischemia neurons during cerebral ischemia and reperfusion were studied. Sixty three Wistar rats were divided randomly into nine groups: control group , ischemia groups including subgroups of is3h, is3 h/rep1 h, is3 h/rep2 h, is3 h/rep3 h, diazepam treated groups , including subgroups of is3 h, is3 h/rep1 h, is3 h/rep2 h, is3 h/rep3 h with Zea longa's animal model of middle cerebral artery occlusion. The comparison between the ischemia group and diazepam treated group showed that diazepam could obviously decrease the production of glutamate, asparate, MDA and increase the synthesis and release of GABA, SOD and GSH PX. It was concluded that diazepam exerted its protective effects on neurons through complex mechanisms of regulating the synthesis and release of excitotary/inhibitory amino acids and free radicals.展开更多
This paper describes a reliable and rapid method for the complete separation and quantitation of twenty-five amino acids typically found in plants, based on reversed phase high-performance liquid chromatography–linke...This paper describes a reliable and rapid method for the complete separation and quantitation of twenty-five amino acids typically found in plants, based on reversed phase high-performance liquid chromatography–linked fluorescence detector using a 150×4.6 mm Zorbax Eclipse AAA column. Plant tissue free amino acids(FAA)were extracted by ultrasonication with 5%(v/v) aqueous trifluoroacetic acid followed by ultrafiltration of extracts.The following analysis of amino acids was performed through programmed precolumn derivatization with orthophthalaldehyde and 9-fluorenylmethyl chloroformate reagents and efficient elution of derivatives within 26 min using binary gradient scheme. The method was validated over a concentration range of 4.5–450 μmol L^(-1)(μM).Separation analysis showed good selectivity(resolution>1.5) for most amino acids. The average repeatability(RSD%, relative standard deviation) of the analysis at seven calibration concentrations was below 4% and ranged from 1.13% to 12.04%. The intra-day mean coefficient of variation at two concentrations(22.5 and 90 μM) was within 2%, and the intermediate precision was less than 4%. The limits of detection were between 0.012 and 6.68 μM. The coefficients of determination(R2) of the linear calibration curves were from 0.9989 to 0.9999.When the method was applied to plant samples, the FAA recoveries at two spiked levels(25 and 100 μM) ranged from 67.0% to 108.9% with an average of 94.4%, and the precision was 0.26%–12.31% RSD. A specific application combining this method with optimized extraction and interference removal procedures was successfully used to determine the FAA pools in different plant tissues. Finally,a PLS-DA multivariate statistics model was validated for the classification of three plant species according to their FAA profiles.展开更多
Using microbial fermentation to increase the content of free amino acids and short peptides in the organic fertilizer for castor bean meal can effectively promote plant growth and improve fruit quality.Using free amin...Using microbial fermentation to increase the content of free amino acids and short peptides in the organic fertilizer for castor bean meal can effectively promote plant growth and improve fruit quality.Using free amino acid and short peptide content as an indicator,through single factor and response surface optimization experiments,the process parameters(moisture content,fermentation time and inoculum quantity)of castor meal solid-state fermentation were optimized.The best process parameters for the solid-state fermentation were:the moisture content 62%,the fermentation time 20 d,and the inoculum quantity 0.23%.The moisture content had the greatest impact on the conversion rate of free amino acids and short peptides,and the protein conversion rate reached 65.6%.The scale-up experiment under the optimal conditions showed that the solid-state fermentation using the inoculum had a significant beneficial effect compared with other fermentation methods.The fermentation of castor cake fertilizer provides a theoretical and practical basis for production feasibility,and has important guiding significance for the effective utilization of castor bean meal.展开更多
The composition and concentration of dissolved free amino acid(DFAA)of seawater samples collected in May 2016 from the surface to the hadal zone of the northern region of the Yap Trench were analyzed by pre-column der...The composition and concentration of dissolved free amino acid(DFAA)of seawater samples collected in May 2016 from the surface to the hadal zone of the northern region of the Yap Trench were analyzed by pre-column derivatization of o-phthalaldehyde.Results show that the average concentration of DFAA in the study area was 0.47±0.36μmol/L.In different sampling stations,the concentrations of DFAA with water depth showed complex variation patterns.At the sediment-seawater interface,the concentrations of DFAA in the western side of the trench were obviously higher than that in its eastern side.In the study area,there were no significant correlations between the concentrations of DFAA and the environmental parameters such as concentrations of chlorophyll a(Chl a),dissolved oxygen(DO),pH,and dissolved inorganic nitrogen(DIN),indicating that the concentrations of DFAA in seawater of the trench are affected by many factors,such as photosynthesis,respiration,temperature,pressure,illumination,and circulation.The dominant DFAA are similar in different water layers of sampling stations,including aspartic acid(Asp),glutamic acid(Glu),glycine(Gly),and serine(Ser).The composition of different amino acids,and the relative abundance of acidic,basic,and neutral amino acids might be related to the sources and consumption of various amino acids.Nine pairs of amino acids in the DFAA showed significantly positive relationship by correlation matrix analysis,suggesting that they might share similar biogeochemical processes.The degradation index(DI)of the DFAA in seawater of the Yap Trench could reflect the degradation,source,and freshness of DFAA in the trench to some extents.This is a preliminary study of amino acids from sea surface to hadal zone in the ocean,more works shall be done in different trenches to reveal their biogeochemical characte ristics in extreme marine environme nts.展开更多
Monthly difference of the chemical composition of oyster cultured along the eastern coast of Shandong Province was analyzed. The components analyzed included glycogen, fatty acid and free amino acid （FAA）. The conte...Monthly difference of the chemical composition of oyster cultured along the eastern coast of Shandong Province was analyzed. The components analyzed included glycogen, fatty acid and free amino acid （FAA）. The content of glycogen was high in January and March （2.89 and 2.82 g（100 g） ^-1 on average, respectively） and low in October （2.07g（100g）^- 1 on average）. The low content of neutral lipids in October reflected a relatively poor nutritional value of oyster （1.42 g（ 100 g）^- 1 on average）. The main fatty acids of oyster were palmitic acid （16：0）, oleic acid （18： 1）, eicosapentaenoic acid （EPA, 20： 5（0 3） and docosahexaenoic acid （DHA, 22：6（0 3）. The major FAAs of oyster were Taurine, Glutamicacid, Glycin, Alanine, Arginine and Proline. Taurine was the most abundant FAA with its content ranging from 603 mg（100 g） ^-1 to 1 139 mg（ 100 g） ^-1. The high contents of glycogen, polyunsaturated fatty acid and FAA showed that oyster cultured along the eastern coast of Shandong Province was nutritionally good in January and March.展开更多
AIM: To perform plasma free amino acid (PFAA) profiling of esophageal squamous cell carcinoma (ESCC) patients at different pathological stages and healthy subjects.
基金supported by the National Natural Science Foundation of China(Grant No.22479097)the Shanghai Science and Technology Committee(Grant Nos.23ZR1433000)the National High-Level Talent Program for Young Scholars,the Start-up Fund(F.S.)from Shanghai Jiao Tong University,China.We also acknowledge the SJTU Instrument Analysis Centre for the measurements.
文摘Two-dimensional nanofluidic membranes have garnered considerable interest due to their potential for cost-effective osmotic energy harvesting.One promising approach to enhancing ion conductivity and selectivity is the incorporation of vip additives.However,the traditional host-vip configuration can undermine the structural integrity of nanochannels owing to the inconsistent size and shape of these additives.Drawing inspiration from the intricate design of biological protein channels,which utilize small amino acid molecules as vips,we have addressed this issue by incorporating glycine,a common amino acid,into a vermiculite membrane using a simple vacuum-assisted infiltration method.The resulting vermiculite-glycine membrane demonstrates 1.8 times greater ionic conductivity and twice the power density compared to pure vermiculite membranes.Analysis based on glycine content,coupled with spectroscopic examination,reveals that ion conductivity is linked to the distribution of glycine molecules across three specific sites within the membrane.This suggests that glycine molecules—whether confined in voids,adsorbed onto nanochannel surfaces,or intercalated within multilayered vermiculite nanoparticles—enhance nanofluidic ion transport by modulating surface and space charge density,as well as strengthening hydrogen bonding,electrostatic interactions,and steric effects.This work reveals the specific interactions between amino acids and vermiculite,offering a novel path for advancing nanofluidic composite membranes and highlighting critical considerations for the proposed strategy.
基金supported by the director of Indian Council of Agricultural Research and International Rice Research Institute (ICAR-CRRI), Cuttack, Indiathe coordinator of the ICAR-sponsored project ‘C-reactive protein (CRP) in Biofortification in Selected Crops’, India
文摘CR Dhan 310(CRD310),a biofortified rice variety,contains a significantly higher level of grain protein compared with its recurrent parent Naveen(NV),as well as most adapted high-yielding rice varieties in India.Although a limited investigation depicted that CRD310 contained higher levels of glutelin and some essential amino acids,detailed biochemical,molecular,and cellular mechanisms remain to be studied.As one of the means to identify the proteins and understand the underlying mechanism of higher proteins accumulation in grains of CRD310,the comparative proteomics was undertaken on grains of CRD310 and NV at the yellow ripening stage.
基金supported by the Natural Science Foundation of Jiangsu Province(No.BK20220409)the National Natural Science Foundation of China(No.22401153)+2 种基金the FWO[Fund for Scientific Research-Flanders(Belgium)]for financial support(recipient Erik V.Van der Eycken)the Research Council of the KU Leuven(recipient Erik V.Van der Eycken)the support of the"RUDN University Strategic Academic Leadership Program"(recipient Erik V.Van der Eycken).
文摘Peptides play important roles in chemistry,medicinal chemistry and life science,due to their high efficiency and specificity,unusual biological and therapeutic properties.As naturally occurring peptides often face with their intrinsic limitations including metabolic instability and low membrane permeability,the strategies for synthesizing unnatural amino acids and peptides are explored.Among the methods for modifying amino acids and peptides,chemo-and site-selective approaches are preferred because of the ability to fine-tuning structural features.Recently,transition metal-catalyzed Csingle bondH activation has been employed for the functionalization of amino acids and peptides.Through domino Csingle bondH activation/annulation,a series of structurally complex and diverse amino acids and peptides is constructed.This review highlights recent advances in the synthesis of unnatural amino acids and peptides via transition metal-catalyzed Csingle bondH activation/annulation.
基金supported by a grant from the Dalian Science and Technology Innovation Fund Program(No.2024JJ13PT070)United Foundation for Dalian Institute of Chemical Physics,Chinese Academy of Sciences and the Second Hospital of Dalian Medical University(No.DMU-2&DICP UN202410)Dalian Life and Health Field Guidance Program Project(No.2024ZDJH01PT084).
文摘Metabolic reprogramming involving branched-chain amino acids(BCAAs)—leucine,isoleucine,and valine—is increasingly recognized as pivotal in cancer progression,metastasis,and immune modulation.This review comprehensively explores how cancer cells rewire BCAA metabolism to enhance proliferation,survival,and therapy resistance.Tumors manipulate BCAA uptake and catabolism via high expression of transporters like L-type amino acid transporter 1(LAT1)and enzymes including branched chain amino acid transaminase 1(BCAT1),branched chain amino acid transaminase 2(BCAT2),branched-chain alpha-keto acid dehydrogenase(BCKDH),and branched chain alpha-keto acid dehydrogenase kinase(BCKDK).These alterations sustain energy production,biosynthesis,redox homeostasis,and oncogenic signaling(especially mammalian target of rapamycin complex 1[mTORC1]).Crucially,tumor-driven BCAA depletion also shapes an immunosuppressive microenvironment,impairing anti-tumor immunity by limiting essential nutrients for T cells and natural killer(NK)cells.Innovative therapeutic strategies targeting BCAA pathways—ranging from selective small-molecule inhibitors(e.g.,LAT1 and BCAT1/2)to dietary modulation—have shown promising preclinical and early clinical efficacy,highlighting their potential to exploit metabolic vulnerabilities in cancer cells while bolstering immune responses.By integrating multi-omics data and precision targeting approaches,this review underscores the translational significance of BCAA metabolic reprogramming,positioning it as a novel frontier in cancer treatment.
基金supported by the National Natural Science Foundation of China(Nos.22404023,22274021,and 22036001).
文摘Chiral amino acids(AAs)serve as essential building blocks of proteins and play vital physiological roles in living organisms.To achieve accurate,rapid,and high-throughput analysis of chiral AAs,this work proposed a methylbenzyl isocyanate(MBIC)derivatization strategy coupled with ultra-high performance liquid chromatography-mass spectrometry or trapped ion mobility spectrometry-mass spectrometry.The integration of a chiral carbon atom with a rigid urea-based structure can significantly enhance the separation of chiral MBIC-labeled AA enantiomers.This phenomenon can be attributed to the labeled l-AAs allow the carboxyl group to form intramolecular hydrogen bonds with the amino group in the rigid urea-based structure,whereas labeled d-AAs are unable to form such bonds.The method based on MBIC derivatization coupled with ultra-performance liquid chromatography-tandem mass spectrometry achieved simultaneous separation of 19 pairs of chiral AAs using only a C18 column within 30 min,enabling quantitatively detect twelve types of chiral AAs in the serum of healthy humans and Parkinson's patients.The distribution of twenty-four chiral AAs is observed in mouse brain using MBIC labeling-based matrix-assisted laser desorption/ionization-trapped ion mobility spectrometry-mass spectrometry imaging without prior separation.Our work elucidates the principles governing the separation of chiral AAs using derivatization methods,providing valuable guidance for the separation of chiral compounds.
基金partly funded by National Key R&D Program of China(2023YFD1301405)the 2115 Talent Development Program of China Agricultural University。
文摘Skeletal muscle accounts for approximately 40%of body mass and 50%–75%of whole-body protein,playing a central role in meat production and quality.Efficient protein synthesis in skeletal muscle relies on an adequate supply of nutrient substrates and a balanced amino acid profile.Branched-chain amino acids(BCAA),including leucine(Leu),isoleucine(Ile),and valine(Val),are the most abundant essential amino acids in skeletal muscle and contribute to both protein synthesis and oxidative energy production.Additionally,BCAA function as signaling molecules that regulate gene expression and protein phosphorylation cascades,which significantly influence physiological processes,such as protein synthesis and degradation,glucose and lipid metabolism,and cell apoptosis and autophagy.These processes are primarily mediated through the PI3K/AKT/AMPK/mTOR signaling pathways.This review summarizes BCAA transporters and catabolic metabolism,their role as signaling molecules in regulating protein metabolism and glucose and lipid equilibrium,and applications in animal production.These findings offer both theoretical insights and practical guidelines for the precise regulation of feed efficiency and production performance through tailored dietary BCAA supplementations.
基金the financial support from the National Natural Science Foundation of China(Nos.22377097,22307036,22074114)Natural Science Foundation of Hubei Province of China(Nos.2020CFB623,2021CFB556)Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education(No.LCX202305)。
文摘The detection of amino acid enantiomers holds significant importance in biomedical,chemical,food,and other fields.Traditional chiral recognition methods using fluorescent probes primarily rely on fluorescence intensity changes,which can compromise accuracy and repeatability.In this study,we report a novel fluorescent probe(R)-Z1 that achieves effective enantioselective recognition of chiral amino acids in water by altering emission wavelengths(>60 nm).This water-soluble probe(R)-Z1 exhibits cyan or yellow-green luminescence upon interaction with amino acid enantiomers,enabling reliable chiral detection of 14 natural amino acids.It also allows for the determination of enantiomeric excess through monitoring changes in luminescent color.Additionally,a logic operation with two inputs and three outputs was constructed based on these optical properties.Notably,amino acid enantiomers were successfully detected via dual-channel analysis at both the food and cellular levels.This study provides a new dynamic luminescence-based tool for the accurate sensing and detection of amino acid enantiomers.
基金financially supported by the Fundamental Research Funds for the Central Universities(JUSRP622014)Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province,Jiangnan University(2022-3-2)National Key Research and Development Program of China(2022YFF1100300).
文摘Post-exercise whey protein isolate(WPI)supplement is beneficial for skeletal muscle recovery due to the stimulation of branched chain amino acids(BCAAs).This implies us that intake slow digestion rate of protein to sustain BCAAs releasing rate may facilitate muscle protein synthesis.To examine this hypothesis,we conducted a series of protein supplements including modified slow-digesting whey(SDW),whey,hydrolyzed whey and casein,orally to mice undergoing endurance running.Our results showed that the SDW gavage constant supplied BCAAs in the serum of mice within 6 h and significantly enhanced(P<0.01)endurance exercise capacity,compared to other groups.In addition,the SDW supplementation increased the crosssectional area of mice gastrocnemius fibers,as well as their muscle and liver glycogen content.It also increased the testosterone/cortisol ratio in serum and interleukin-6(IL-6)levels in muscle,while it decreased the tumor necrosis factor-alpha(TNF-α)levels and oxidative stress in muscle.Moreover,it may activate mechanistic target of rapamycin signaling by upregulating mRNA(bcat-1 and pgc-1α)expression.Thus,our findings illustrate that prolonged BCAAs supply duration promotes mice endurance running capacity and skeletal muscle growth,contributing to the advancement of sports nutrition practices.
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 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financially supported by the National Natural Science Foundation of China (no. 31272510)the Science Foundation of Xi'an (no. NC1405(1))the Innovation Fund of Graduate Student of Northwest University (no. YZZ13034)
文摘The amino acid contents of five floral sources Chinese honeys(jujube, rape, chaste, acacia, and lungan) were measured using reversed phase high-performance liquid chromatography(RP-HPLC). The results showed that proline was the main amino acid in most of the analyzed samples. Phenylalanine presents at the highest content in chaste honey samples, and the total amino acid contents of chaste honeys were also significantly higher than those of other honey samples. Based on the amino acid contents, honey samples were classified using chemometric methods(cluster analysis(CA), principal component analysis(PCA), and discriminant analysis(DA)). According to the CA results, chaste honeys could be separated from other honeys, while the remaining samples were correctly grouped together when the chaste honey data were excluded. By using DA, the overall correct classification rate reached 100%. The results revealed that amino acid contents could potentially be used as indicators to identify the botanical origin of unifloral honeys.
基金The authors are grateful for the financial support from National Natural Science Foundation of China(32001728).
文摘Free amino acid(FAA)is the important component of vinegar that infl uences quality perception and consumer acceptance.FAA is one of the major metabolites produced by microorganisms;however,the microbial metabolic network on FAA biosynthesis remains unclear.Through metagenomic analysis,this work aimed to elucidate the roles of microbes in FAA biosynthesis during Monascus rice vinegar fermentation.Taxonomic profiles from functional analyses showed 14 dominant genera with high contributions to the metabolism pathways.The metabolic network for FAA biosynthesis was then constructed,and the microbial distribution in different metabolic pathways was illuminated.The results revealed that 5 functional genera were closely involved in FAA biosynthesis.This study illuminated the metabolic roles of microorganisms in FAA biosynthesis and provided crucial insights into the functional attributes of microbiota in vinegar fermentation.
基金financially supported by the National Key Basic Research Program of China (2012CB124702, 2013CB127302)National Natural Science Foundation of China (31272452)the National Key Technology R&D Program of China (2011BAD26B01)
文摘Background： The current study was carried out to determine effects of dietary protein source and crude protein（CP）level on carcass characteristics, meat quality, and muscle amino acid（AA） profile in finishing gilts. The experiment was designed as a 2 × 2 factorial arrangement with two sources of dietary proteins（cottonseed meal, CSM vs. soybean meal, SBM） and two levels of CP（12 % vs. 14 %, as-fed basis）. Seventy-two crossbred gilts（89.5 ± 0.9 kg） were allotted to one of four dietary treatments in a randomized complete block design for a period of 28 d. All diets were formulated to be isoenergetic and similar concentrations of standardized ileal digestible essential AA covering the nutrient requirements of pigs.Results： Growth, carcass characteristics and meat quality were not affected by dietary protein source nor crude protein level（P ＆gt; 0.10） except that average daily feed intake was increased by CSM diets（P = 0.03）. Gilts offered reduced protein diets had lower muscle p H45min（P 〈 0.05）. Neither dietary protein source nor crude protein level influenced N deposition. However, reduced protein diets decreased N intake, N excretion, and serum urea nitrogen content, whilst improved N efficiency（P 〈 0.01）. CSM diets increased N intake（P = 0.04）,but did not depress N efficiency. The concentrations of phenylalanine, tryptophan, cysteine and tyrosine（P 〈 0.05） of the longissimus muscle were decreased when gilts offered CSM diets, while muscle intracellular free valine concentration was increased（P = 0.03）. The gilts offered reduced protein diets had greater intracellular concentrations of free methionine, lysine, and total AA in muscle（P 〈 0.05）.Conclusion： These results suggest that CSM could replace SBM as a primary protein source in finishing pig diets in terms of performance, N efficiency, carcass characteristics, and meat quality, but decrease the concentrations of muscle specific AA. Furthermore, the reduced protein diet played an important role in increasing muscle intracellular concentrations of specific free amino acids（FAA）, and in reducing the relative ratios of specific FAA to lysine in longissimus dorsi muscle of pig, whose biological meaning needs further studies.
基金This project was supported by a grant from a nationalnatural sciences foundation of China (No. 30 0 40 0 37)
文摘The protective effect and mechanism of diazepam on ischemia neurons during cerebral ischemia and reperfusion were studied. Sixty three Wistar rats were divided randomly into nine groups: control group , ischemia groups including subgroups of is3h, is3 h/rep1 h, is3 h/rep2 h, is3 h/rep3 h, diazepam treated groups , including subgroups of is3 h, is3 h/rep1 h, is3 h/rep2 h, is3 h/rep3 h with Zea longa's animal model of middle cerebral artery occlusion. The comparison between the ischemia group and diazepam treated group showed that diazepam could obviously decrease the production of glutamate, asparate, MDA and increase the synthesis and release of GABA, SOD and GSH PX. It was concluded that diazepam exerted its protective effects on neurons through complex mechanisms of regulating the synthesis and release of excitotary/inhibitory amino acids and free radicals.
基金financially supported by the National Key Research and Development Program of China through Grant 2016YFA0601000(H.Y.Xiao)National Natural Science Foundation of China through Grants 41425014,41273027 and 41173027(H.Y.Xiao)by the National Basic Research Program of China through Grants 2013CB956703(H.Y.Xiao)
文摘This paper describes a reliable and rapid method for the complete separation and quantitation of twenty-five amino acids typically found in plants, based on reversed phase high-performance liquid chromatography–linked fluorescence detector using a 150×4.6 mm Zorbax Eclipse AAA column. Plant tissue free amino acids(FAA)were extracted by ultrasonication with 5%(v/v) aqueous trifluoroacetic acid followed by ultrafiltration of extracts.The following analysis of amino acids was performed through programmed precolumn derivatization with orthophthalaldehyde and 9-fluorenylmethyl chloroformate reagents and efficient elution of derivatives within 26 min using binary gradient scheme. The method was validated over a concentration range of 4.5–450 μmol L^(-1)(μM).Separation analysis showed good selectivity(resolution>1.5) for most amino acids. The average repeatability(RSD%, relative standard deviation) of the analysis at seven calibration concentrations was below 4% and ranged from 1.13% to 12.04%. The intra-day mean coefficient of variation at two concentrations(22.5 and 90 μM) was within 2%, and the intermediate precision was less than 4%. The limits of detection were between 0.012 and 6.68 μM. The coefficients of determination(R2) of the linear calibration curves were from 0.9989 to 0.9999.When the method was applied to plant samples, the FAA recoveries at two spiked levels(25 and 100 μM) ranged from 67.0% to 108.9% with an average of 94.4%, and the precision was 0.26%–12.31% RSD. A specific application combining this method with optimized extraction and interference removal procedures was successfully used to determine the FAA pools in different plant tissues. Finally,a PLS-DA multivariate statistics model was validated for the classification of three plant species according to their FAA profiles.
基金Special Fund for International Cooperative Research of Qilu University of Technology(QLUTGJHZ2018010)。
文摘Using microbial fermentation to increase the content of free amino acids and short peptides in the organic fertilizer for castor bean meal can effectively promote plant growth and improve fruit quality.Using free amino acid and short peptide content as an indicator,through single factor and response surface optimization experiments,the process parameters(moisture content,fermentation time and inoculum quantity)of castor meal solid-state fermentation were optimized.The best process parameters for the solid-state fermentation were:the moisture content 62%,the fermentation time 20 d,and the inoculum quantity 0.23%.The moisture content had the greatest impact on the conversion rate of free amino acids and short peptides,and the protein conversion rate reached 65.6%.The scale-up experiment under the optimal conditions showed that the solid-state fermentation using the inoculum had a significant beneficial effect compared with other fermentation methods.The fermentation of castor cake fertilizer provides a theoretical and practical basis for production feasibility,and has important guiding significance for the effective utilization of castor bean meal.
基金Supported by the Natural National Science Foundation of China(Nos.42076040,41676067)the National Basic Research Program of China(973 Program)(No.2015CB755904)the 111 Project(No.B13030)。
文摘The composition and concentration of dissolved free amino acid(DFAA)of seawater samples collected in May 2016 from the surface to the hadal zone of the northern region of the Yap Trench were analyzed by pre-column derivatization of o-phthalaldehyde.Results show that the average concentration of DFAA in the study area was 0.47±0.36μmol/L.In different sampling stations,the concentrations of DFAA with water depth showed complex variation patterns.At the sediment-seawater interface,the concentrations of DFAA in the western side of the trench were obviously higher than that in its eastern side.In the study area,there were no significant correlations between the concentrations of DFAA and the environmental parameters such as concentrations of chlorophyll a(Chl a),dissolved oxygen(DO),pH,and dissolved inorganic nitrogen(DIN),indicating that the concentrations of DFAA in seawater of the trench are affected by many factors,such as photosynthesis,respiration,temperature,pressure,illumination,and circulation.The dominant DFAA are similar in different water layers of sampling stations,including aspartic acid(Asp),glutamic acid(Glu),glycine(Gly),and serine(Ser).The composition of different amino acids,and the relative abundance of acidic,basic,and neutral amino acids might be related to the sources and consumption of various amino acids.Nine pairs of amino acids in the DFAA showed significantly positive relationship by correlation matrix analysis,suggesting that they might share similar biogeochemical processes.The degradation index(DI)of the DFAA in seawater of the Yap Trench could reflect the degradation,source,and freshness of DFAA in the trench to some extents.This is a preliminary study of amino acids from sea surface to hadal zone in the ocean,more works shall be done in different trenches to reveal their biogeochemical characte ristics in extreme marine environme nts.
基金This work was supported by the National High Technology Development Project of China （Grant No. AA625030） the Natural Science Foundation of Qingdao （Grant No. 04-2 JZ-110）.
文摘Monthly difference of the chemical composition of oyster cultured along the eastern coast of Shandong Province was analyzed. The components analyzed included glycogen, fatty acid and free amino acid （FAA）. The content of glycogen was high in January and March （2.89 and 2.82 g（100 g） ^-1 on average, respectively） and low in October （2.07g（100g）^- 1 on average）. The low content of neutral lipids in October reflected a relatively poor nutritional value of oyster （1.42 g（ 100 g）^- 1 on average）. The main fatty acids of oyster were palmitic acid （16：0）, oleic acid （18： 1）, eicosapentaenoic acid （EPA, 20： 5（0 3） and docosahexaenoic acid （DHA, 22：6（0 3）. The major FAAs of oyster were Taurine, Glutamicacid, Glycin, Alanine, Arginine and Proline. Taurine was the most abundant FAA with its content ranging from 603 mg（100 g） ^-1 to 1 139 mg（ 100 g） ^-1. The high contents of glycogen, polyunsaturated fatty acid and FAA showed that oyster cultured along the eastern coast of Shandong Province was nutritionally good in January and March.
基金Supported by National Natural Science Foundation of China,Grant No.81360356Scientific Research Foundation of Xinjiang Medical University,Grant No.XJC201221
文摘AIM: To perform plasma free amino acid (PFAA) profiling of esophageal squamous cell carcinoma (ESCC) patients at different pathological stages and healthy subjects.
