Effects of improved amino acid balance diet on lysine mammary utilization, whole body protein turnover and muscle protein breakdown on lactating sows

Background The study objective was to test the hypothesis that low crude protein(CP)diet with crystalline amino acids(CAA)supplementation improves Lys utilization efficiency for milk production and reduces protein turnover and muscle protein breakdown.Eighteen lactating multiparous Yorkshire sows were allotted to 1 of 2 isocaloric diets(10.80 MJ/kg net energy):control(CON;19.24%CP)and reduced CP with“optimal”AA profile(OPT;14.00%CP).Sow body weight and backfat were recorded on d 1 and 21 of lactation and piglets were weighed on d 1,14,18,and 21 of lactation.Between d 14 and 18,a subset of 9 sows(CON=4,OPT=5)was infused with a mixed solution of 3-[methyl-2H3]histidine(bolus injection)and[13C]bicarbonate(priming dose)first,then a constant 2-h[13C]bicarbonate infusion followed by a 6-h primed constant[1-13C]lysine infusion.Serial blood and milk sampling were performed to determine plasma and milk Lys enrichment,Lys oxidation rate,whole body protein turnover,and muscle protein breakdown.Results Over the 21-d lactation period,compared to CON,sows fed OPT had greater litter growth rate(P<0.05).Compared to CON,sows fed OPT had greater efficiency of Lys(P<0.05),Lys mammary flux(P<0.01)and whole-body protein turnover efficiency(P<0.05).Compared to CON,sows fed OPT tended to have lower whole body protein breakdown rate(P=0.069).Muscle protein breakdown rate did not differ between OPT and CON(P=0.197).Conclusion Feeding an improved AA balance diet increased efficiency of Lys and reduced whole-body protein turnover and protein breakdown.These results imply that the lower maternal N retention observed in lactating sows fed improved AA balance diets in previous studies may be a result of greater partitioning of AA towards milk rather than greater body protein breakdown.

Low crude protein formulation with supplemental amino acids for its impacts on intestinal health and growth performance of growing-finishing pigs

Background Low crude protein(CP)formulations with supplemental amino acids(AA)are used to enhance intestinal health,reduce costs,minimize environmental impact,and maintain growth performance of pigs.However,extensive reduction of dietary CP can compromise growth performance due to limited synthesis of non-essential AA and limited availability of bioactive compounds from protein supplements even when AA requirements are met.Moreover,implementing a low CP formulation can increase the net energy(NE)content in feeds causing excessive fat deposition.Additional supplementation of functional AA,coupled with low CP formulation could further enhance intestinal health and glucose metabolism,improving nitrogen utilization,and growth performance.Three experiments were conducted to evaluate the effects of low CP formulations with supplemental AA on the intestinal health and growth performance of growing-finishing pigs.Methods In Exp.1,90 pigs(19.7±1.1 kg,45 barrows and 45 gilts)were assigned to 3 treatments:CON(18.0%CP,supplementing Lys,Met,and Thr),LCP(16.0%CP,supplementing Lys,Met,Thr,Trp,and Val),and LCPT(16.1%CP,LCP+0.05%SID Trp).In Exp.2,72 pigs(34.2±4.2 kg BW)were assigned to 3 treatments:CON(17.7%CP,meeting the requirements of Lys,Met,Thr,and Trp);LCP(15.0%CP,meeting Lys,Thr,Trp,Met,Val,Ile,and Phe);and VLCP(12.8%CP,meeting Lys,Thr,Trp,Met,Val,Ile,Phe,His,and Leu).In Exp.3,72 pigs(54.1±5.9 kg BW)were assigned to 3 treatments and fed experimental diets for 3 phases(grower 2,finishing 1,and finishing 2).Treatments were CON(18.0%,13.8%,12.7%CP for 3 phases;meeting Lys,Met,Thr,and Trp);LCP(13.5%,11.4%,10.4%CP for 3 phases;meeting Lys,Thr,Trp,Met,Val,Ile,and Phe);and LCPG(14.1%,12.8%,11.1%CP for 3 phases;LCP+Glu to match SID Glu with CON).All diets had 2.6 Mcal/kg NE.Results In Exp.1,overall,the growth performance did not differ among treatments.The LCPT increased(P<0.05)Claudin-1 expression in the duodenum and jejunum.The LCP and LCPT increased(P<0.05)CAT-1,4F2hc,and B0AT expressions in the jejunum.In Exp.2,overall,the VLCP reduced(P<0.05)G:F and BUN.The LCP and VLCP increased(P<0.05)the backfat thickness(BFT).In Exp.3,overall,growth performance and BFT did not differ among treatments.The LCPG reduced(P<0.05)BUN,whereas increased the insulin in plasma.The LCP and LCPG reduced(P<0.05)the abundance of Streptococcaceae,whereas the LCP reduced(P<0.05)Erysipelotrichaceae,and the alpha diversity.Conclusions When implementing low CP formulation,CP can be reduced by supplementation of Lys,Thr,Met,Trp,Val,and Ile without affecting the growth performance of growing-finishing pigs when NE is adjusted to avoid increased fat deposition.Supplementation of Trp above the requirement or supplementation of Glu in low CP formulation seems to benefit intestinal health as well as improved nitrogen utilization and glucose metabolism.

Mepiquat chloride increases the Cry1Ac protein content of Bt cotton under high temperature and drought stress by regulating carbon and amino acid metabolism

The effects of mepiquat chloride(DPC)on the Cry1Ac protein content in Bacillus thuringiensis(Bt)cotton boll shells under high temperature and drought stress were investigated to provide a theoretical reference for Bt cotton breeding and high-yield and-efficiency cotton cultivation.This study was conducted using Bt cotton cultivar‘Sikang 3'during the 2020 and 2021 growing seasons at Yangzhou University Farm,Yangzhou,Jiangsu Province,China.Potted cotton plants were exposed to high temperature and drought stress,and sprayed with either 20 mg L^(-1)DPC or water(CK).Seven days after treatment,the Cry1Ac protein content,α-ketoglutarate content,pyruvic acid content,glutamate synthase activity,glutamic oxaloacetic transaminase activity,soluble protein content,and amino acid content were measured,and transcriptome sequencing was performed.DESeq was used for differential gene analysis.Under the DPC treatment,the Cry1Ac protein content increased by 4.7-11.9% compared to CK.Theα-ketoglutarate content,pyruvic acid content,glutamate synthase activity,glutamic oxaloacetic transaminase activity,soluble protein content,and amino acid content all increased.Transcriptome analysis revealed 7,542 upregulated genes and 10,449 downregulated genes for DPC vs.CK.Gene ontology(GO)and Kyoto Encyclopedia of Gene and Genomes(KEGG)analyses showed that the differentially expressed genes were mainly involved in biological processes,such as carbon and amino acid metabolism.For example,genes encoding 6-phosphofructokinase,pyruvate kinase,glutamic pyruvate transaminase,pyruvate dehydrogenase,citrate synthase,isocitrate dehydrogenase,2-oxoglutarate dehydrogenase,glutamate synthase,1-pyrroline-5-carboxylate dehydrogenase,glutamic oxaloacetic transaminase,amino-acid N-acetyltransferase,and acetylornithine deacetylase were all significantly upregulated.The DPC treatment increased pyruvate,α-ketoglutarate,and oxaloacetate by increasing the operational rate of the glycolytic pathway of the citric acid cycle.It also significantly upregulated the genes encoding glutamate synthase,pyrrolidine-5-carboxylic acid dehydrogenase,glutamate oxaloacetate transaminase,and N-acetylglutamate synthetase,while it downregulated the genes encoding glutamine synthetase.Therefore,the synthesis of aspartic acid,glutamic acid,pyruvate,and arginine increased after treatment with DPC,and the Cry1Ac protein content was increased by regulating carbon and amino acid metabolism.

Estimation of endogenous protein and amino acid ileal losses in weaned piglets by regression analysis using diets with graded levels of casein

Background： Many studies have investigated endogenous loss of proteins and amino acids （AAs） at the ileal level in growing pigs. However, only a few studies have researched this subject in piglets. Knowledge regarding AA ileal digestibility in piglets would be helpful during the formulation of diets for weaning piglets, rather than just using coefficients obtained in growing pigs. Therefore, in this study, we sought to estimate endogenous protein and AA ileal losses in piglets. Furthermore, apparent and true ileal digestibility （AID and TID） of protein and AAs from casein were measured. Results： The average flow of protein was 20.8 g/kg of dry matter intake （DMI）. Basal protein loss, as estimated by regression, was 16.9 g/kg DMI. Glutamic acid, arginine, and aspartic acid （2.2, 1.4, and 1.2 g/kg DMI, respectively） were the AAs for which greater losses were seen. The AID of protein and AAs increased as the protein level in the diet increased. A higher increment in AID was observed between diets with 80 and160 g CP/kg of feed; this finding was mainly attributable to increases in glycine and arginine （46.1% and 18%, respectively）. The TID of protein was 97.8, and the TID of AAs varied from 93.9 for histidine to 100.2 for phenylalanine. Conclusions： The basal endogenous protein loss in piglets was 16.9 g/kg DMI. Endogenous protein was rich in glutamic acid, aspartic acid, and arginine, which represented 32.7% of endogenous protein loss in weaning piglets. The TID of casein was high and varied from 93.0 for histidine to 100.2 for phenylalanine.

Metagenomic analysis revealing the metabolic role of microbial communities in the free amino acid biosynthesis of Monascus rice vinegar during fermentation

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.

Advancing energy storage with nitrogen containing biomaterials utilizing amino acid, peptide and protein: Current trends and future directions

As the climate crisis continues to escalate, there has been a growing emphasis on the development of electrode materials that are environmentally friendly and sustainable. Biomolecules, such as proteins,peptides, and amino acids, have emerged as promising alternatives to metal oxide and metal hydroxide-based energy storage systems. These biomolecules offer several advantages, such as high safety, non-toxicity, abundant raw material sources, and ease of device fabrication. In this review, we highlighted the recent advancements in amino acid, peptide, and protein-based materials for lithiumion batteries, supercapacitors, and fuel cells. We delve into the synthetic strategies employed and their impact on factors such as active potential window, solubility in the electrolyte, and electrochemical performance. Our focus is on the development, composition, and performance of biomolecules, as well as the various approaches taken for their application in batteries, supercapacitors, and fuel cells. Finally, we discuss key considerations that must be taken into account to promote the design, synthesis and development for future practical applications of lithium-ion batteries, supercapacitors, and fuel cells.

Protein Content and Amino Acid Composition in Grains of Wheat-Related Species

The protein content and amino acid composition for 17 wheat-related species （WRS） and three common wheats （control） were determined and analyzed, and the essential amino acids （EAAs） in WRS were evaluated according to FAO/WHO amino acid recommendations. The results showed that the mean protein content for WRS was 16.67%, which was 23.21% higher than that for the control. The mean contents （g 100 g^-1 protein） of most amino acids for WRS were lysine 2.74%, threonine 2.83%, phenylalanine 4.17%, isoleucine 3.42%, valine 3.90%, histidine 2.81%, glutamic acid 29.96%, proline 9.12%, glycine 3.59%, alanine 3.37%, and cysteine 1.57%, which were higher than those for the control. The contents of the other 6 amino acids for WRS were lower than those for the control. The materials （Triticum monococcum L., Triticum carthlicum Nevski, and Triticum turgidum L.） contained relatively high concentration of the most deficient EAAs （lysine, threonine, and methionine）. Comparing with FAO/WHO amino acid recommendations, the amino acid scores （AAS） of lysine （49.8%）, threonine （70.7%）, and sulfur-containing amino acids （74.8%） were the lowest, which were considered as the main limiting amino acids in WRS. It was observed that the materials with Triticum urartu Turn. （AA） and Aegilops speltoides Tausch. （SS） genomes had relatively high contents of protein and EAA. The contents of protein （16.91%）, phenylalanine （4.78%）, isoleucine （3.53%）, leucine （6.16%）, and valine （4.09%） for the diploid materials were higher than those for the other materials. These results will provide some information for selecting parents in breeding about nutrient quality and utilization of fine gene in wheat.

High Temperature During Rice Grain Filling Enhances Aspartate Metabolism in Grains and Results in Accumulation of AspartateFamily Amino Acids and Protein Components

Global warming causes the exacerbation of rice growing environment, which seriously affects rice growth and reproduction, and finally results in the decrease of rice yield and quality. We investigated the activities of aspartate metabolism enzymes in grains, and the contents of Aspartate-family amino acids and protein components to further understand the effects of high temperature （HT） on rice nutritional quality during rice grain filling. Under HT, the average activities of aspartate aminotransferase （AAT） and aspartokinase （AK） in grains significantly increased, the amino acid contents of aspartate （Asp）, lysine （Lys）, threonine （Thr）, methionine （Met） and isoleucine （lie） and the protein contents of albumin, globulin, prolamin and glutelin also significantly increased. The results indicated that HT enhanced Asp metabolism during rice grain filling and the enhancement of Asp metabolism might play an important role in the increase of Asp-family amino acids and protein components in grains. In case of the partial appraisal of the change of Asp-family amino acids and protein components under HT, we introduced eight indicators （amino acid or protein content, ratio of amino acid or protein, amino acid or protein content per grain and amino acid or protein content per panicle） to estimate the effects of HT. It is suggested that HT during rice grain filling was benefit for the accumulation of Asp-family amino acids and protein components. Combined with the improvement of Asp-family amino acid ratio in grains under HT, it is suggested that HT during grain filling may improve the rice nutritional quality. However, the yields of parts of Asp-family amino acids and protein components were decreased under HT during rice grain filling.

Regulation of protein degradation pathways by amino acids and insulin in skeletal muscle of neonatal pigs

Background： The rapid gain in lean mass in neonates requires greater rates of protein synthesis than degradation. We previously delineated the molecular mechanisms by which insulin and amino acids, especially leucine, modulate skeletal muscle protein synthesis and how this changes with development. In the current study, we identified mechanisms involved in protein degradation regulation. In experiment 1,6- and 26-d-old pigs were studied during 1） euinsulinemic-euglycemic-euaminoacidemic, 2） euinsulinemic-euglycemiohyperaminoacidemic, and 3） hyperinsulinemic-euglycemic-euaminoacidemic clamps for 2 h. In experiment 2, 5-d-old pigs were studied during 1） euinsulinemic-euglycemic-euaminoacidemic-euleucinemic, 2） euinsulinemic-euglycemic-hypoaminoacidemic- hyperleucinemic, and 3） euinsulinemic-euglycemic-euaminoacidemic-hyperleucinemic clamps for 24 h. We determined in muscle indices of ubiquitin-proteasome, i.e., atrogin-1 （MAFbx） and muscle RING-finger protein-1 （MuRF1） and autophagy-lysosome systems, i.e., unc51-1ike kinase 1 （UKL1）, microtubule-associated protein light chain 3 （LC3）, and lysosomal-associated membrane protein 2 （Lamp-2）. For comparison, we measured ribosomal protein 56 （rpS6） and eukaryotic initiation factor 4E （elF4E） activation, components of translation initiation. Results： Abundance of atrogin-1, but not MuRF1, was greater in 26- than 6-d-old pigs and was not affected by insulin, amino acids, or leucine. Abundance of ULK1 and LC3 was higher in younger pigs and not affected by treatment. The LC3-11/LC3-1 ratio was reduced and ULK1 phosphorylation increased by insulin, amino acids, and leucine. These responses were more profound in younger pigs. Abundance of Lamp-2 was not affected by treatment or development. Abundance of elF4E, but not rpS6, was higher in 6- than 26-d-old-pigs but unaffected by treatment. Phosphorylation of elF4E was not affected by treatment, however, insulin, amino acids, and leucine stimulated rpS6 phosphorylation, and the responses decreased with development.

Evaluation of Protein Concentration, Amino Acid Profile and Antinutritional Compounds in Hempseed Meal from Dioecious and Monoecious Varieties

Hempseed meal from three dioecious and three monoecious varieties has been evaluated for content and quality of the protein and for the concentration of antinutritional compounds. Hemp seeds were obtained from plants grown in two experimental fields for two consecutive years (2011-2012). For all the varieties, hempseed meal resulted in a rich source of protein (34% mean content) with an amino acid profile extremely rich in arginine and slightly poor in lysine. Differences between dioecious and monoecious varieties were observed in the content of antinutritional compounds. They were more concentrated in monoecious varieties in comparison with those dioecious. The concentration of phytic acid in hempseed meal deserves attention in both groups, being 63 and 75.4 g·kg-1 of dry matter in dioecious and monocieous varieties, respectively. The results show that, besides the recognized value of hemp oil, also the hempseed cake could find application in animal feed as a substitute of other cakes (soybean, rapeseed). From this point of view, the dioecious varieties showing lower contents of antinutritional compounds with respect to the monoecious varieties would be preferred.

Cinnamicaldehyde regulates the expression of tight junction proteins and amino acid transporters in intestinal porcine epithelial cells

Background： Cinnamicaldehyde（CA） is a key flavor compound in cinnamon essential oil possessing various bioactivities. Tight junction（TJ） proteins are vital for the maintenance of intestinal epithelial barrier function,transport, absorption and utilization of dietary amino acids and other nutrients. In this study, we tested the hypothesis that CA may regulate the expression of TJ proteins and amino acid transporters in intestinal porcine epithelial cells（IPEC-1） isolated from neonatal pigs.Results： Compared with the control, cells incubated with 25 μmol/L CA had increased transepithelial electrical resistance（TEER） and decreased paracellular intestinal permeability. The beneficial effect of CA on mucosal barrier function was associated with enhanced protein abundance for claudin-4, zonula occludens（ZO）-1, ZO-2, and ZO-3. Immunofluorescence staining showed that 25 μmol/L CA promoted the localization of claudin-1 and claudin-3 to the plasma membrane without affecting the localization of other TJ proteins, including claudin-4, occludin,ZO-1, ZO-2, and ZO-3, compared with the control cells. Moreover, protein abundances for rBAT, xCT and LAT2 in IPEC-1 cells were enhanced by 25 μmol/L CA, while that for EAAT3 was not affected.Conclusions： CA improves intestinal mucosal barrier function by regulating the distribution of claudin-1 and claudin-3 in enterocytes, as well as enhancing protein abundance for amino acid transporters rBAT, xCT and LAT2 in enterocytes. Supplementation with CA may provide an effective nutritional strategy to improve intestinal integrity and amino acid transport and absorption in piglets.

Identification of QTL Affecting Protein and Amino Acid Contents in Rice

The phenotypes of protein and amino acid contents were measured in an F9 recombinant inbred line population derived from a cross between Zhenshan 97B and Delong 208. A total of 48 and 64 QTLs were identified in 2004 and 2005, respectively. The contribution of each QTL to the phenotypic variation ranged from 4.0% to 43.7%. Most QTLs co-localized, forming 29 QTL clusters on the chromosomes with three major ones detected in both years, which were mapped on chromosomes 1, 7 and 9, respectively. The two QTL clusters for amino acid content, qAa1 and qAa7, influenced almost all the traits with the allele from Zhenshan 97B, and the third QTL cluster for amino acid content, qAa9, increased the lysine content with the allele from Delong 208. A wide coincidence was found between the QTL detected under this study and the loci involved in amino acid metabolism pathways in nitrogen assimilation and transport, or protein biosynthesis. The results would facilitate the identification of candidate genes and could be used in marker-assisted selection for the favorable allele in rice quality improvement.

Changes of Protein and Lipid Contents,Amino Acid and Fatty Acid Compositions in Eggs and Yolk-Sac Larvae of American Shad(Alosa sapidissima)

To investigate the changes of the biochemical composition of American shad(Alosa sapidissima) eggs and larvae at embryonic and early larval stages, samples were collected at different development stages from artificial fertilization to the end of yolk absorption including 2 h, 12 h and 30 h after fertilization and newly hatched larvae including 1 and 3 days after hatching. The composition of lipid, fatty acids, protein and amino acids were analyzed. The content of total protein exhibited a decreasing trend during embryogenesis and larval development, and a significant reduction was detected after hatching(P < 0.05). The total lipid content remained relative stable. A significant reduction was detected in almost all amino acids after hatching except for glycine(P <0.05), while a significant decrease was found in the content of cysteine, proline, tyrosine, valine, isoleucine, leucine and phenylalanine during the yolk-sac phase(P < 0.05). On the other hand, all the groups of fatty acids remained stable during the period of embryogenesis. But after hatching, a significant decrease was found in the content of C18:2n-6, C18:3n-6, SFA and ratio of EPA/ARA(P < 0.05), while a significant increase was found in the content of C18:3n-3, C20:4n-6, C22:6n-3 and ratio of n-3/n-6(P < 0.05). In conclusion, the combined data suggested that American shad utilizes the protein content as preferential energy substrates during embryonic and early larval developments with some specificity in the consumption of different amino acids.

Reduced protein diet with near ideal amino acid profile improves energy efficiency and mitigate heat production associated with lactation in sows

Background:The study objective was to test the hypothesis that 1)lowering dietary crude protein(CP)increases dietary energetic efficiency and reduces metabolic heat associated with lactation,and 2)excessive dietary leucine(Leu)supplementation in a low CP diet decreases dietary energetic efficiency and increases metabolic heat associated with lactation.Methods:Fifty-four lactating multiparous Yorkshire sows were allotted to 1 of 3 isocaloric diets(10.80 MJ/kg net energy):1)control(CON;18.75%CP),2)reduced CP with a near ideal or optimal AA profile(OPT;13.75%CP)and 3)diet OPT with excessive Leu(OPTLEU;14.25%CP).Sow body weight and backfat were recorded on day 1 and 21 of lactation and piglets were weighed on day 1,4,8,14,18,and 21 of lactation.Energy balance was measured on sows during early(day 4 to 8)and peak(day 14 to18)lactation,and milk was sampled on day 8 and 18.Results:Over 21-day lactation,sows fed OPT lost body weight and body lipid(P<0.05).In peak lactation,sows fed OPT had higher milk energy output(P<0.05)than CON.Sows fed OPTLEU tended(P=0.07)to have less milk energy output than OPT and did not differ from CON.Maternal energy retention was lower(P<0.05)in OPT and OPTLEU compared to CON sows,and did not differ between OPTLEU and OPT sows.Sows fed OPT had higher(P<0.05)apparent energy efficiency for milk production compared to CON.Heat production associated with lactation was lower(P<0.05)or tended to be lower(P=0.082),respectively,in OPT and OPTLEU compared to CON sows.Conclusion:The OPT diet,in peak lactation,improved dietary energy utilization for lactation due to less urinary energy and metabolic heat loss,and triggered dietary energy deposition into milk at the expense of maternal lipid mobilization.Leucine supplementation above requirement may reduce dietary energy utilization for lactation by decreasing the energy partitioning towards milk,partially explaining the effectiveness of OPT diet over CON diets.

Differences in the Content of Protein and Essential Amino Acids between Different Rice Varieties

Evaluation of the protein content is a major indicator of the nutritional quality of rice,and the protein quality of rice is the best among cereal crops. Essential amino acids play an irreplaceable role in human growth,development and health care. Essential amino acid is a key ingredient to measure the nutritional value of rice. Using the experimental rice processed from the rice variety " Yuzhenxiang" sprayed with plant nutrients( patent number: ZL201110103910. 9),namely high essential amino acid nutritional rice,combined with five kinds of high quality rice imported by COFCO and homegrown " Wuchang rice",we send the samples of the seven kinds of rice to Hunan Food Testing Center,and adopt HPLC method to test the content of protein and eight kinds of essential amino acids. Three bags of rice are randomly selected for each kind of rice,and each bag is a replication. The test results show that there are highly significant differences in the content of essential amino acids between different kinds of rice( F = 246. 29**,P =5 ×10- 71),and there are also highly significant differences in the content between different kinds of essential amino acids( F = 3937. 09**,P = 4 × 10- 146). The test results of protein content indicate that there are highly significant differences in the content of protein between different kinds of rice( F = 3937. 0973. 29**,P =5. 81 ×10- 11),and the test results of lysine content show that there are highly significant differences in the content of lysine between different kinds of rice( F =3937. 0973. 29**,P =5. 81 ×10- 11).

The structural analysis of protein sequences based on the quasi-amino acids code

Proteomics is the study of proteins and their interactions in a cell. With the successful completion of the Human Cenome Project, it comes the postgenome era when the proteomics technology is emerging. This paper studies protein molecule from the algebraic point of view. The algebraic system （∑, ＋, ＊） is introduced, where ∑ is the set of 64 codons. According to the characteristics of （∑, ＋, ＊）, a novel quasi-amino acids code classification method is introduced and the corresponding algebraic operation table over the set ZU of the 16 kinds of quasi-amino acids is established. The internal relation is revealed about quasi-amino acids. The results show that there exist some very close correlations between the properties of the quasi-amino acids and the codon. All these correlation relationships may play an important part in establishing the logic relationship between codons and the quasi-amino acids during the course of life origination. According to Ma F et al （2003 J. Anhui Agricultural University 30 439）, the corresponding relation and the excellent properties about amino acids code are very difficult to observe. The present paper shows that （ZU, ＋,×） is a field. Furthermore, the operational results display that the eodon tga has different property from other stop codons. In fact, in the mitochondrion from human and ox genomic codon, tga is just tryptophane, is not the stop codon like in other genetic code, it is the case of the Chen W C et al （2002 Acta Biophysiea Siniea 18（1） 87）. The present theory avoids some inexplicable events of the 20 kinds of amino acids code, in other words it solves the problem of ＇the 64 codon assignments of mRNA to amino acids is probably completely wrong＇ proposed by Yang （2006 Progress in Modern Biomedicine 6 3）.

Analysis of Amino Acids in a Single Human Red Blood Cell by Capillary Zone Electrophoresis with Intracellular NDA- derivatization and Electrochemical Detection

A novel method for determination of amino acids in individual human red blood cells has been developed. In this method, the derivatization reagents (NDA and CN-) are introduced into living cells by electroporation. After completion of derivatization, the amino acids in a single cell is determined by capillary zone electrophoresis with end-column amperometric detection.

Influences of dietary protein sources and crude protein levels on intracellular free amino acid profile in the longissimus dorsi muscle of finishing gilts

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.

The market for amino acids: understanding supply and demand of substrate for more efficient milk protein synthesis

For dairy production systems, nitrogen is an expensive nutrient and potentially harmful waste product. With three quarters of fed nitrogen ending up in the manure, significant research efforts have focused on understanding and mitigating lactating dairy cows' nitrogen losses. Recent changes proposed to the Nutrient Requirement System for Dairy Cattle in the US include variable efficiencies of absorbed essential AA for milk protein production. This first separation from a purely substrate-based system, standing on the old limiting AA theory, recognizes the ability of the cow to alter the metabolism of AA. In this review we summarize a compelling amount of evidence suggesting that AA requirements for milk protein synthesis are based on a demand-driven system. Milk protein synthesis is governed at mammary level by a set of transduction pathways, including the mechanistic target of rapamycin complex 1(mTORC1), the integrated stress response(ISR), and the unfolded protein response(UPR). In tight coordination, these pathways not only control the rate of milk protein synthesis, setting the demand for AA, but also manipulate cellular AA transport and even blood flow to the mammary glands, securing the supply of those needed nutrients. These transduction pathways, specifically mTORC1, sense specific AA, as well as other physiological signals, including insulin, the canonical indicator of energy status. Insulin plays a key role on mTORC1 signaling, controlling its activation, once AA have determined mTORC1 localization to the lysosomal membrane.Based on this molecular model, AA and insulin signals need to be tightly coordinated to maximize milk protein synthesis rate. The evidence in lactating dairy cows supports this model, in which insulin and glucogenic energy potentiate the effect of AA on milk protein synthesis. Incorporating the effect of specific signaling AA and the differential role of energy sources on utilization of absorbed AA for milk protein synthesis seems like the evident following step in nutrient requirement systems to further improve N efficiency in lactating dairy cow rations.

Relationship between Witches' Broom Protein and Dynamic of Some Amino Acids in Paulownia Tree Leaves

This paper dealt with the SDS polyacrymide gel electrophoresis of proteins ahd analysis of the amino acids in the diseasedand healthy leaves with the same strain respectively, which were at the same side and height, of Paulownia catalpifolia, P. elongata, P. albiphloea and P. kauakamii respectively. The results indicated that the leaves of 4 species of Paulownia trees with witches' broom had one protein band, of which molecular weight was 12 kD, which did not appear in the healthy leaves free of phytoplasmas. Moreover, the protein quantity in the affected leaves was more than that in the healthy leaves free of phytoplasmas, At the same time, there was significant difference on the amino acids between the healthy and diseased leaves of P. catalpifolia and P. kawakamii. The amount of cystine in the affected leaves was higher than that in the healthy leaves, but the change of amount of phenylalanine in the affected and healthy leaves was contrary.These changes of proteins and amino acids in the leaves might be related to the witches' broom of the Parlounia trees.