Arginine Concentrations Research Articles

Promoted alkanolamine solutions with amino acid L-arginine for post-combustion CO2 capture in a micro-reactor

With the aim of replacing amine solvents, in the current study, the novel mixture solutions were proposed for CO2 absorption combining amino acid (L-Arginine) with primary, secondary, and tertiary alkanolamines. The mass transfer performance of CO2 capture in the aqueous solutions of MEA-ARG, DEA-ARG, and MDEA-ARG was intensified under operational conditions of 4–12 wt% arginine concentration, 120–300 mL/min feed solvent flow rate, 3–9 mL/min inlet gas flow rate. In this regard, a T-shape micro-reactor with a diameter of 800 μ and a length of 29.5 cm was utilized. All the experiments were performed under the atmospheric pressure and absorption temperature of 45 °C. Considering industrial restrictions, the total concentration of mixtures was kept constant at 25 wt% for MEA-ARG, 35 wt% for DEA-ARG, and 50 wt% for MDEA-ARG. The results of CO2 absorption efficiency (ef), overall volumetric mass transfer coefficient, OVGMTC, (KGaV), and volumetric mass transfer flux (NAaV) indicated that in all three cases, the aqueous MEA-ARG solution has the highest value of 96%, 90.95 kmol/m3.h.kPa, and 361.82 kmol/h.m3, respectively. Also, while the gas and liquid flow rates were kept constant in their middle points, adding arginine from 4 to 12 wt% enhanced the values of the ef from 92.55% to 93.76% for DEA-ARG and from 79.20% to 93.23% for MDEA-ARG solutions, respectively. However, the results were obtained differently for solution MEA-ARG.

Nutrition of free-living Neotropical psittacine nestlings and implications for hand-feeding formulas.

Psittacidae is one of the most endangered families of birds in the world. Knowledge of their nutrition is important for understanding their survival and productivity in the wild, as well as for their adequate husbandry under human care. Hand-rearing is a common practice for psittacines, however research on their nutrition is limited. We analysed the predicted metabolisable energy, crude protein, crude fat, mineralsand the essential amino acid profiles of the crop contents from free-living nestlings of scarlet macaws (Ara macao) and red-and-green macaws (Ara chloropterus) from southeastern Peru, Cuban Amazons (Amazona leucocephala bahamensis) from the Bahamas, lilac-crowned Amazons (Amazona finschi) from northwestern Mexicoand thick-billed parrots (Rhynchopsitta pachyrhyncha) from northern Mexico. The crop content of the different parrot species displayed remarkably similar nutritional profiles, considering their diversity in habitats, geographic rangesand food sources. The crude protein and crude fat concentrations in crop samples were particularly similar for the Ara and Amazona species, while the thick-billed parrot stood out for its higher crude fat and lower crude protein content. Wider variations were found among the concentrations of sodium (Na) and iron (Fe), prolineand tryptophan. Compared with the requirements of 6-12weeksleghorn chickens, all free-ranging parrot diets contained lower crude protein, calcium (Ca), potassium (P)and Na concentrations. The hand-feeding formulas contained lower crude fat, magnesium (Mg), arginine, valine and phenylalanine concentrations, as well as much higher levels of Ca and zinc (Zn), in comparison with parrot crop samples. Our data suggest that a single formulation could be used to hand-rear Ara and Amazona sp. of 3weeks of age and older, while a different formulation would likely be more appropriated for Rhynchopsitta sp. Experimental studies should evaluate if increasing the concentration of crude fat, Mg, arginine, valineand phenylalanine enhances psittacine chick growth and health.

P870: DEFINING A NOVEL FUNCTION FOR THE POST-TRANSLATIONAL MODIFICATION UFMYLATION IN THE ADAPTIVE RESPONSE TO ARGININE DEPRIVATION IN MULTIPLE MYELOMA

Background: Our previous work showed that arginine deprivation is associated to multiple myeloma (MM) bortezomib refractoriness, but the molecular basis of this adaptive response is still largely unknown. Aims: We designed an integrative transcriptional and metabolic study to explore the contemporary transcriptional and metabolic changes occurring upon arginine deprivation in four human myeloma cell lines (HMCLs, U266, NCI-H929, OPM2 and MM1.s). Methods: HMCLs were individually cultured with customized complete with different Arg concentrations, correspondent respectively to 100%, 25% and 10% of the arginine concentration in MM bone marrow. After 24-48 hours of culture, the cells were collected for global metabolomic analysis (Metabolon Inc) and transcriptome profiling by Illumina platform. Apoptosis and mitochondrial depolarization were measured by FACS. Protein expression was evaluated by western blot analysis. Results: In all tested HMCLs the progressive arginine deprivation (range 1124-0 µM) induced delay in cell cycle until proliferation arrest (in total lack of arginine in culture media), with increase of G0-G1 length, at specific timepoints for each cell line tested. However global protein synthesis was not affected and surprisingly, in all tested cell lines, the monoclonal component secretion in extracellular medium was preserved after 96 hours of arginine starvation. At 48 hours of arginine deprivation (range 1124-100 µM) GCN2 pathway was induced in HMCLs with consequent increase of basal levels of ATF4, p62, GABARAP and autophagy flux. After 48 hours of arginine starvation, coupled metabolomics and RNA-seq, disclosed an impairment in the pool of nucleotides and activation of salvage purine pathway, that could explain changes in cell cycle and proliferation. Arginine-deprived MM cells had higher levels of choline and phospho-ethanolamine with lower levels of glycerophosphorylcholine (GPC) compared to controls suggesting an effect of arginine-deprivation on membrane dynamics, associated to increased production of fatty acids, palmitate (16:0) and stearate (18:0), required for the generation of new membranes. Culture in arginine deficient media resulted in complete depletion of reduced glutathione (GSH) and oxidized glutathione (GSSG), with depletion of gamma-glutamylcysteine, indicating increased levels of oxidative stress. Gene set enrichment analysis (GSEA) showed deep transcriptome rearrangements, involving upregulation of genes required for the unfolded protein response, NF-kB response to TNF, p53 pathway and networks and proteosome degradation, with a minimal effect on metabolism features, except the upregulation of genes involved in lactate generation and degradation. In all cell lines, transcripts involved in the UFMylation pathway were affected, with reduction of UFSP2 and increase of UFMYlation targets RPL26, PKM2, ENO-1, PGK-1 and SQSTM1/p62. In a large series of primary samples (9N - 20MGUS - 33SMM - 170MM - 24PPCL - 12SPCL) and 18 MM cell lines, through bioinformatic analysis of previously published datasets (GENE1.0_BAv20_Neri-Gutierrez), we found that myeloma progression was associated to increased expression of UFMYlation targets ENO-1, PGK1 and DLD. Summary/Conclusion: Taken together, our data clearly indicate how arginine starvation can induce an heterogeneous adaptation processes occur in individual tumour clones. The ER stress adaptive response triggered by arginine deprivation promotes UFMylation activation, due to downregulation of UFSP2 and accumulation of RPN1/RPL26 targets.

Dietary Arginine Modulates Growth Performance, Hemato-Biochemical Indices, Intestinal Enzymes, Antioxidant Ability and Gene Expression of TOR and 4E-BP1 in Rainbow Trout, Oncorhynchus mykiss Fingerlings

We evaluated the effect of arginine on growth, hemato-biochemical variables, intestinal enzymes, antioxidant ability, and expression of target of rapamycin (TOR) signaling pathway related genes in fingerling Oncorhynchus mykiss. A series of six uniform diets consisting of 450 g kg-1 of protein and 20.9 g-1 of energy with graduated levels (10.0, 12.5, 15.0, 17.5, 20.0, and 22.5 g kg-1) of arginine were formulated. Significant (p < 0.05) variations were observed in various analyzed parameters. Growth parameters showed a positive linear trend with increasing arginine levels up to 17.5 g kg-1. Fish offered 17.5 g kg-1 of dietary arginine exhibited highest body protein, lowest moisture, and intermediate fat contents, whereas, body ash content did not significantly (p > 0.05) change with respect to each dietary arginine offered diet, except for the lowest levels. Each group also produced significant (p < 0.05) changes in their hematological variables with maximum hemoglobin (Hb), hematocrit (Hct) content, and red blood cell (RBC) count noted at 17.5 g kg-1 arginine diet. Although the majority of blood plasma parameters were insignificantly (p > 0.05) different with respect to varied arginine fed diets, plasma aspartate transaminase (AST) showed significant (p < 0.05) variations across the treatments. Moreover, total protein, alkaline phosphatase (ALP) and albumin contents increased significantly (p < 0.05) with increasing arginine concentrations up to 17.5 g kg-1 and, thereafter, a declined trend in these parameters were noted. Intestinal enzymes and antioxidant properties showed significant (p < 0.05) variations, except plasma amylase, which showed insignificant variation. The maximum up-regulation of TOR and 4E-BP1 gene expression levels were found for fish fed 17.5 g kg-1 of dietary arginine compared to the lower (10.0 and 12.5 g kg-1) and higher (20.0 and 22.5 g kg-1) arginine levels, which indicates that fish utilize arginine more efficiently at this point. Quadratic regression analysis of live weight gain (LWG), feed conversion ratio (FCR), protein efficiency ratio (PER) and body protein deposition (BPD) indicated the optimal arginine requirement of rainbow trout to be 17.61 g kg-1 of dry diet, corresponding to 39.13 g kg-1 of dietary protein, which enhances growth, immunity, antioxidant ability, and also promote TOR signaling pathway in rainbow trout.

Comparison of Amino Acid Concentrations in Plasma and Dried Blood Spot Samples Using LC-MS/MS

Background: Dried blood spot samples are suitable for diagnosing some congenital errors of metabolism; however, they provide limited benefit in the regular monitoring of amino acids. Objectives: The present study aimed to evaluate alanine (Ala), arginine (Arg), citrulline (Cit), glutamic acid (Glu), glycine (Gly), isoleucine (Ileu), leucine (Leu), methionine (Met), ornithine (Orn), phenylalanine (Phe), tyrosine (Tyr), and valine (Val) amino acid concentrations in dried blood and plasma samples obtained simultaneously. Methods: Amino acid concentrations were determined in the plasma, and dried blood spot samples obtained simultaneously from 145 patients (50 females and 95 males). Amino acid concentrations in the plasma and dried blood spot samples were studied by LC-MS/MS using original kits. Results: There were significant differences between dried blood spots and plasma in all amino acid concentrations, except for Met and Val. Bland-Altman analysis revealed the highest mean differences in Glu (-148.1), Gly (-70.1), and Ala (-58.1). Deming regression analysis showed that plasma and dried blood spot samples were consistent concerning Cit, Met, Phe, and Tyr concentrations. Conclusions: Differences in methodology and sample can influence amino acid concentrations. Dried blood spot samples might cause errors in amino acid screening programs.

Associations Between Ambient Temperature and Circulating Maternal One-carbon and Amino Acid Metabolites in Pregnancy

ObjectivesExcessive ambient temperature closely linked to climate change is an imminent threat to the health of mothers and children globally. Recent studies have shown detrimental associations between high temperatures during pregnancy and birth outcomes. The goal of this study was to examine relationships between circulating metabolites in the mother and environmental temperature in a resource-limited setting. MethodsThe study was a secondary analysis employing data from the Women First (WF) trial conduced in Thatta, Pakistan. As part of the trial, women of child-bearing age either consumed a comprehensive maternal nutritional supplement (MNS) prior to conception until delivery (Arm 1), from 12 wk gestation until delivery (Arm 2); or were not supplemented with MNS Arm 3. Daily maximum air temperatures were acquired from the closest surface observation systems (n = 131). Average daily maximum temperatures (Tmax) for a 90-day window representing the 1st trimester of pregnancy was calculated for each participant. The number of days in this period when the Tmax was > 39°C was computed to assess ‘heat stress days’. Maternal blood was collected on dried blood spot (DBS) cards at 34 wk gestation. A targeted metabolomics assay measuring concentrations of 23 metabolites was performed on DBS samples using LC-MS/MS. ResultsLinear regression was employed to assess the associations between ambient temperature in the 1st trimester and metabolite levels (z-scores). Models were adjusted for MNS supplementation. Significant associations between Tmax in the 1st trimester and 7 metabolites were observed (FDR p-values < 0.05). Of these, maternal choline concentrations were negatively correlated with maximal temperature in the 1st trimester (β = –0.063, p = 4.3e-10). Concentrations of glutamine, histidine, arginine, symmetrical-dimethylarginine, methionine and cysteine were positively associated (p < 0.05) with daily maximal temperature. ConclusionsCollectively, the findings indicate that exposure to excessive heat stress in the first trimester is associated with lower choline levels and other metabolites important in blood pressure regulation. While the findings are associative, our results point to underlying mechanistic alterations in maternal circulation in concert with environmental heat stress. Funding SourcesBill & Melinda Gates Foundation; NIH/NICHD/ODS.

Alterations in meat nutrient composition in response to a partial replacement of corn with triticale in the broiler diet

Abstract The study evaluated the effect of feeding triticale on proximate composition, amino acids (AA) profile and nutritional value of meat (breast and thigh) of broiler chickens. A 5-weeks trial (1-35d) was conducted on Cobb 500 broilers (n=400), allotted into two dietary groups with five replicates (40 birds/replicate) and fed control (C, corn-soybean meal) and triticale (T, corn-triticale-soybean meal) diets. Broilers meat’s proximate composition and energy value showed no significant differences between treatments. Feeding triticale significantly increased (P&lt;0.05) breast muscle concentrations of arginine, valine and phenylalanine, while the methionine and alanine decreased (P&lt;0.05) and did not affect the total AA, essential, non-essential or flavor AA. Concerning the thigh muscle AA profile, partial corn replacing with triticale decreased (P&lt;0.05) the content of isoleucine, leucine, serine and alanine, without altering the total AA, EAA, NEAA, flavor AA or their ratio. The limiting AA in both muscle types was leucine, irrespective of diet. The EAA index and net protein value revealed no significant differences between diets or muscle types. In conclusion, partial corn replacement in broilers’ diets with triticale did not adversely affect the proximate meat composition and positively impacted broilers’ nutritional meat protein quality.

The Role of Fecal Microbiota in Liver Toxicity Induced by Perfluorooctane Sulfonate in Male and Female Mice.

Background:Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant that can cause hepatotoxicity. The underlying toxicological mechanism remains to be investigated. Given the critical role of fecal microbiota in liver function, it is possible that fecal microbiota may contribute to the liver toxicity induced by PFOS.Objectives:We aimed to investigate the role of liver-fecal microbiota axis in modulating PFOS-induced liver injury in mice.Methods:Male and female mice were exposed to PFOS or vehicle for 14 d. In this investigation, 16S rDNA sequencing and metabolomic profiling were performed to identify the perturbed fecal microbiota and altered metabolites with PFOS exposure. In addition, antibiotic treatment, fecal microbiota transplantation, and bacterial administration were conducted to validate the causal role of fecal microbiota in mediating PFOS-induced liver injury and explore the potential underlying mechanisms.Results:Both male and female mice exposed to PFOS exhibited liver inflammation and steatosis, which were accompanied by fecal microbiota dysbiosis and the disturbance of amino acid metabolism in comparison with control groups. The hepatic lesions were fecal microbiota-dependent, as supported by antibiotic treatment and fecal microbiota transplantation. Mice with altered fecal microbiota in antibiotic treatment or fecal microbiota transplantation experiments exhibited altered arginine concentrations in the liver and feces. Notably, we observed sex-specific lower levels of key microbiota, including Lactobacillus, Enterococcus, and Akkermansia. Mice treated with specific bacteria showed lower arginine levels and lower expression of the phosphorylated mTOR and P70S6K, suggesting lower activity of the related pathway and mitigation of the pathological differences observed in PFOS-exposed mice.Conclusions:Our study demonstrated the critical role of the fecal microbiota in PFOS-induced liver injury in mice. We also identified several critical bacteria that could protect against liver injury induced by PFOS in male and female mice. Our present research provided novel insights into the mechanism of PFOS-induced liver injury in mice. https://doi.org/10.1289/EHP10281

Genome of the parasitoid wasp Cotesia chilonis sheds light on amino acid resource exploitation

BackgroundA fundamental feature of parasitism is the nutritional exploitation of host organisms by their parasites. Parasitoid wasps lay eggs on arthropod hosts, exploiting them for nutrition to support larval development by using diverse effectors aimed at regulating host metabolism. However, the genetic components and molecular mechanisms at the basis of such exploitation, especially the utilization of host amino acid resources, remain largely unknown. To address this question, here, we present a chromosome-level genome assembly of the parasitoid wasp Cotesia chilonis and reconstruct its amino acid biosynthetic pathway.ResultsAnalyses of the amino acid synthetic pathway indicate that C. chilonis lost the ability to synthesize ten amino acids, which was confirmed by feeding experiments with amino acid-depleted media. Of the ten pathways, nine are known to have been lost in the common ancestor of animals. We find that the ability to synthesize arginine was also lost in C. chilonis because of the absence of two key genes in the arginine synthesis pathway. Further analyses of the genomes of 72 arthropods species show that the loss of arginine synthesis is common in arthropods. Metabolomic analyses by UPLC-MS/MS reveal that the temporal concentrations of arginine, serine, tyrosine, and alanine are significantly higher in host (Chilo suppressalis) hemolymph at 3 days after parasitism, whereas the temporal levels of 5-hydroxylysine, glutamic acid, methionine, and lysine are significantly lower. We sequence the transcriptomes of a parasitized host and non-parasitized control. Differential gene expression analyses using these transcriptomes indicate that parasitoid wasps inhibit amino acid utilization and activate protein degradation in the host, likely resulting in the increase of amino acid content in host hemolymph.ConclusionsWe sequenced the genome of a parasitoid wasp, C. chilonis, and revealed the features of trait loss in amino acid biosynthesis. Our work provides new insights into amino acid exploitation by parasitoid wasps, and this knowledge can specifically be used to design parasitoid artificial diets that potentially benefit mass rearing of parasitoids for pest control.

A Phase 1 study of ADI‐PEG20 (pegargiminase) combined with cisplatin and pemetrexed in ASS1‐negative metastatic uveal melanoma

Metastatic uveal melanoma (UM) is a devastating disease with few treatment options. We evaluated the safety, tolerability and preliminary activity of arginine depletion using pegylated arginine deiminase (ADI‐PEG20; pegargiminase) combined with pemetrexed (Pem) and cisplatin (Cis) chemotherapy in a phase 1 dose‐expansion study of patients with argininosuccinate synthetase (ASS1)‐deficient metastatic UM. Eligible patients received up to six cycles of Pem (500 mg/m2) and Cis (75 mg/m2) every 3 weeks plus weekly intramuscular ADI (36 mg/m2), followed by maintenance ADI until progression (NCT02029690). Ten of fourteen ASS1‐deficient patients with UM liver metastases and a median of one line of prior immunotherapy received ADIPemCis. Only one ≥ grade 3 adverse event of febrile neutropenia was reported. Seven patients had stable disease with a median progression‐free survival of 3.0 months (range, 1.3–8.1) and a median overall survival of 11.5 months (range, 3.2–36.9). Despite anti‐ADI‐PEG20 antibody emergence, plasma arginine concentrations remained suppressed by 18 weeks with a reciprocal increase in plasma citrulline. Tumour rebiopsies at progression revealed ASS1 re‐expression as an escape mechanism. ADIPemCis was well tolerated with modest disease stabilisation in metastatic UM. Further investigation of arginine deprivation is indicated in UM including combinations with immune checkpoint blockade and additional anti‐metabolite strategies.

Chemotherapy Drugs Induce Cachexia and Alter Muscle Protein Metabolism

Chemotherapy is the main regimen to treat neoplastic tumours. Maintenance of muscle mass during treatment is associated with greater patient prognosis and reduces toxicity and severe side effects. However, chemotherapy induces cachexia, a wasting disorder characterized by muscle weakness and a loss of muscle mass. Although cancer, a disease treated with chemotherapy, is often diagnosed in older individuals, studies investigating chemotherapy‐induced cachexia are done exclusively in young animals at an age equivalent to a 20‐year‐old human. Therefore, studies investigating the effects of chemotherapy‐induced cachexia at an age range relevant to humans is needed. The objective of this study is to compare the severity and mechanisms of chemotherapy‐induced cachexia in 3‐month‐old adult (equivalent to a 20‐year‐old human) and 18‐month‐old (equivalent to a 56‐year‐old human) mice. Three‐month‐old adult CD2F1 male mice were treated with either folfiri (50mg/kg 5‐fluorouracil (5FU), 90mg/kg Leucovorin and 24mg/kg CPT11) (drug) or vehicle (10% DMSO in saline) for 6‐weeks. Male mice aged to 18‐months will undergo similar treatments. Adult mice treated with the drug cocktail exhibited significant body weight loss (~10%, n=4, p=0.0117) with no differences in food intake. Decreases in body weight were associated with a loss of muscle mass in the gastrocnemius (~25%, n=4, p=0.006), quadriceps (~30%, n=4, p=0.019) and tibialis anterior (~40%, n=4, p&lt;0.0001). Insulin tolerance tests at weeks 3 and 6 of treatment were also performed and glucose levels were found to be non‐significantly higher in drug‐treated mice. Signalling factors related to the mammalian/mechanistic target of rapamycin complex 1 (mTORC1), protein synthesis, autophagy and the ubiquitin proteasome system will be measured. Key enzymes responsible for the breakdown of the branched chain amino acids (BCAAs), mainly branched‐chain alpha‐ketoacid dehydrogenase complex (BCKD) and branched‐chain amino acid transferase 2 (BCAT2) will also be measured in the skeletal muscle. Along this line, in cell culture, we have previously shown decreased (~20%) activity of the BCKD enzyme, corresponding with decreased amino acid concentrations of leucine (~40%), isoleucine (~60%), valine (~50%), alanine (~30%), arginine (~60%), phenylalanine (50%), serine (50%) and glutamate (50%) in chemotherapy‐treated myotubes. We also observed decreased (~65%) expression of amino acid transporters sodium‐coupled neutral amino acid transporter 1 (SNAT1) and large neutral amino acid transporter 1 (LAT1). Timepoint analysis showed SNAT1 expression to be decreased prior to decreases in BCKD activity, signifying that alterations in BCAA metabolism may be a result of decreased levels of BCAAs and amino acids in chemotherapy‐treated myotubes. Therefore, these findings stemmed our interest in how the BCAAs, and their metabolites are affected in‐vivofollowing chemotherapy treatment. Findings from this study will help to elucidate whether unique signatures of cachexia are experienced in older mice. Better understanding of the mechanisms underlying muscle mass regulation following chemotherapy treatment may help combat cachexia.

Postprandial Effects of Salmon Fishmeal and Whey on Metabolic Markers in Serum and Gene Expression in Liver Cells.

Fish is considered an important part of a healthy diet, in part due to the content of long chain omega-3 fatty acids. However, both lean and fatty fish have beneficial health effects, suggesting that micronutrients and proteins may play a role. In a randomised, controlled, cross-over trial, five healthy male participants consumed 5.2 g of protein from either salmon fishmeal or whey. Blood samples were taken before and 30 and 60 min after intake. The concentration of glucose, lipids, hormones and metabolites, including 28 different amino acids and derivatives, were measured in serum or plasma. Cultured HepG2 cells were incubated with or without serum from the participants, and transcriptomic profiling was performed using RNA sequencing. The ingestion of both salmon fishmeal and whey reduced the glucose and triglyceride levels in serum. Protein intake, independent of the source, increased the concentration of 22 amino acids and derivatives in serum. Fishmeal increased the concentration of arginine, methionine, serine, glycine, cystathionine and 2-aminobutyric acid more than whey did. Incubation with postprandial serum resulted in large transcriptomic alterations in serum-fasted HepG2 cells, with the differential expression of >4500 protein coding genes. However, when comparing cells cultivated in fasting serum to postprandial serum after the ingestion of fishmeal and whey, we did not detect any differentially regulated genes, neither with respect to the protein source nor with respect to the time after the meal. The comparable nutrigenomic effects of fishmeal and whey do not change the relevance of fish by-products as an alternative food source.

Effect of the combination of low temperature vacuum heating with tea polyphenol on AGEs in sturgeon fillets

SummaryThis study aimed to elucidate the information mechanism of advanced glycation end products (AGEs) in sturgeon fillets, and its inhibition by polyphenol. The results revealed that LTVH fillets (processed using low temperature vacuum heating method, LTVH) did not have lower values of AGEs than those treated using TC method (a typical thermal procedure using boiling water at 100 °C). The addition of tea polyphenol, on the other hand, drastically reduced the AGEs levels in LTVH fillets. An in vitro model including sturgeon myofibrillar protein and glucose was employed in this work to evaluate the inhibition of AGEs by tea polyphenol. The results showed that free Arginine was susceptible to interaction with glucose, which caused the development of AGEs. However, the addition of tea polyphenol competed with glucose for binding to free Arginine, leading to a substantial decrease in free Arginine concentration and an increase of free amino loss rate, resulting in the inhibition of AGEs generation. The LTVH technique, in combination with tea polyphenol, can be used to prevent the production of AGEs on fillets during the thermal treatment.

Oral Administration of L-Citrulline Changes Brain Free Amino Acid and Monoamine Metabolism in Heat-Exposed Broiler Chickens

High ambient temperatures (HT) in summer are becoming more severe due to global warming, leading to severe adverse effects on poultry production. Recently, we have reported that oral administration of L-citrulline (L-Cit) can minimize hyperthermia in chickens under HT. However, whether oral L-Cit can enter the brain, the center for thermoregulation, has not been studied. We investigated the effects of oral administration of L-Cit on free amino acids and monoamines in the diencephalon region of the brain of heat-exposed broilers. Broilers were treated with L-Cit (40 mmol/20 ml/bird), then moved to a chamber at HT (30 ± 1°C) or to a thermoneutral temperature (CT: 22 ± 1°C) chamber for 2 h. Control groups were given methyl cellulose solution and placed in the CT or HT chambers. After 2 h of exposure to HT, there were increased brain concentrations of Cit in comparison with concentrations in broilers exposed to CT, whereas brain ornithine (Orn) concentrations were decreased, and arginine (Arg) concentrations were not changed. Interestingly, oral administration of L-Cit increased brain concentration of Cit, Arg, and Orn under both CT and HT. Tryptophan and its metabolite, serotonin (5-HT) concentrations were lower in the brain under HT than under CT. HT did not change brain concentrations of tyrosine, but dopamine (DA, a metabolite of tyrosine) concentrations decreased, and methoxyhydroxyphenylglycol (MHPG, a metabolite of DA) concentrations increased in comparison with CT. Oral administration of L-Cit decreased brain concentrations of both tryptophan and tyrosine under CT and HT without changing 5-HT; however, DA levels declined under HT. Moreover, MHPG concentrations increased. In conclusion, these results suggest that metabolism of amino acids and metabolism of DA can be enhanced in the brain by oral administration of L-Cit. Metabolic changes in the brain in response to oral administration of L-Cit may influence the thermoregulatory center in the brain, leading to a reduction in body temperature and conferring thermotolerance in heat-exposed broiler chickens.

Photoperiodic Changes in Both Hypothalamus Neurotransmitters and Circulating Gonadal Steroids Metabolomic Profiles in Relation to Seasonal Reproduction in Male Quail.

Both hypothalamic neurotransmitters and serum steroid hormones are impacted by photoperiod and have effects on physiology and seasonal reproductive. However, the relationship between circulating gonadal steroids and hypothalamic neurotransmitters underlying different photoperiod is still unclear. To further understand the crosstalk of neurotransmitters and steroids in seasonal reproduction, metabolic changes of 27 neurotransmitters concentrated in hypothalamus tissues and 42 steroids hormones in serum were assessed during two artificial photoperiodic programs. The results showed that photoperiod induce testicular atrophy and recrudescence. In L-to-S groups, significantly decreased levels of testosterone concentration were found in serum (P < 0.001) and increased 11-Dehydrocorticosterone (P < 0.05); Testosterone were almost undetectable at SD_14d. In addition, the hypothalamus exhibited significantly increased arginine and 4-aminobutyric acid (GABA) concentration and decreased serotonin and epinephrine content (P < 0.01 or P < 0.05). Accordingly, serum testosterone and androstenedione became detectable at LD_3d in the S-to-L group and were markedly increase at LD_7d. Furthermore, Serum androstenedione showed a significant increase with long light expose (P < 0.01). Additionally, the hypothalamus exhibited both significantly increased L.Tryptophan and phenylalanine concentration, as well as decreased L-glutamine and L-glutamine.acid content (P < 0.01 or P < 0.05). Serotonin metabolism showed significant differences between L-to-S group and S-to-L group. Furthermore, in the correlation analysis, serum testosterone had a positive correlation with 5-Hydroxyindole-3-acetic acid (5-HIAA), while Androstenedione was significantly negative with L.Tryptophan in L-to-S (P < 0.05). However, in S-to-L group, serum testosterone showed strong negative correlation with both serotonin and 5-HIAA (P < 0.05), but positive correlation with L.Tryptophan (P < 0.01), while Androstenedione was significantly negative correlation with both serotonin (P < 0.05) and L-Glutamine (P < 0.01). Photoperiod also had significant effects on the mRNA expression. We found significant differences in gene expression patterns of both serotonin signaling and steroid biosynthesis, while MAOB, NR5A1, and 3β-HSD showed an opposite tendency between two groups. Taken together, our results revealed that circulating gonadal steroids and hypothalamic neurotransmitters were significantly impact quail’s seasonal reproduction. Circulating gonadal steroids have different effects on neurotransmitter at different photoperiodism, which may coordinately influence the seasonal reproduction of quails.

Trichloroethylene modifies energy metabolites in the amniotic fluid of Wistar rats

Exposure to trichloroethylene (TCE), an industrial solvent, is associated with several adverse pregnancy outcomes in humans and decreased fetal weight in rats. However, effects of TCE on energy metabolites in amniotic fluid, which have associations with pregnancy outcomes, has not been published previously. In the current exploratory study, timed-pregnant Wistar rats were exposed to 480 mg TCE/kg/day via vanilla wafer or to vehicle (wafer) alone from gestational day (GD) 6–16. Amniotic fluid collected on GD 16 was analyzed for metabolites important in energy metabolism using short chain fatty acid and tricarboxylic acid plus platforms (N = 4 samples/sex/treatment). TCE decreased concentrations of the following metabolites in amniotic fluid for both fetal sexes: 6-phosphogluconate, guanosine diphosphate, adenosine diphosphate, adenosine triphosphate, and flavin adenine dinucleotide. TCE decreased fructose 1,6-bisphosphate and guanosine triphosphate concentrations in amniotic fluid of male but not female fetuses. Moreover, TCE decreased uridine diphosphate-D-glucuronate concentrations, and increased arginine and phosphocreatine concentrations, in amniotic fluid of female fetuses only. No metabolites were increased in amniotic fluid of male fetuses. Pathway analysis suggested that TCE altered folate biosynthesis and pentose phosphate pathway in both sexes. Using metabolite ratios to investigate changes within specific pathways, some ratio alterations, including those in arginine metabolism and phenylalanine metabolism, were detected in females only. Ratio analysis also suggested enzymes, including gluconokinase, as potential TCE targets. Together, results from this exploratory study suggest that TCE differentially modified energy metabolites in amniotic fluid based on sex. These findings may inform future studies of TCE reproductive toxicity.

Equine enterocytes actively oxidize l-glutamine, but do not synthesize l-citrulline or l-arginine from l-glutamine or l-proline in vitro.

In livestock species, the enterocytes of the small intestine are responsible for the synthesis of citrulline and arginine from glutamine and proline. At present, little is known about de novo synthesis of citrulline and arginine in horses. To test the hypothesis that horses of different age groups can utilize glutamine and proline for the de novo synthesis of citrulline and arginine, jejunal enterocytes from 19 horses of three different age groups: neonates (n = 4; 7.54 ± 2.36 d of age), adults (n = 9; 6.4 ± 0.35 yr), and aged (n = 6; 22.9 ± 1.0 yr) with healthy gastrointestinal tracts were used in the present study. Enterocytes were isolated from the jejunum and incubated at 37 °C for 30 min in oxygenated (95% O2/5% CO2) Krebs bicarbonate buffer (pH 7.4) containing 5 mM D-glucose and 0 mM, 2-mM L-[U-14C]glutamine, or 2 mM L-[U-14C]proline plus 2 mM L-glutamine. Concentrations of arginine, citrulline, and ornithine in cells plus medium were determined using high-performance liquid chromatography. Results indicate that the rate of oxidation of glutamine to CO2 was high in enterocytes from neonatal horses, but low in cells from adult and aged horses. Enterocytes from all age groups of horses did not degrade proline into CO2. Regardless of age, equine enterocytes formed ornithine from glutamine and proline, but failed to convert ornithine into citrulline and arginine. Because arginine is an essential substrate for the synthesis of not only proteins, but also nitrogenous metabolites (e.g., nitric oxide, polyamines, and creatine), our novel findings have important implications for the nutrition, performance, and health of horses.

Arginine requirement for egg production in Japanese quail

The objective of this study was to determine the ideal arginine intake for egg production in Japanese quail using the dilution technique. A completely random design was used, with 8 treatments (seven concentrations of arginine plus a control diet) and ten replicates, totaling 80 Japanese quails. The digestible arginine levels included in the study were 0.361%, 0.603%, 0.843%, 1.084%, 1.204%, 1.311%, and 1.460%. The variables analyzed were feed intake, egg production (EP), egg weight, egg output (EO), feed conversion ratio, and body weight were performed using a mixed model. When the effect of arginine levels (P ≤ 0.05) was detected, the model's broken line linear-plateau (BL), quadratic-plateau (BLq), and the first intercept of the BLq in the plateau of BL were adjusted to determine the ideal arginine intake. It observed that the arginine levels modified the quail responses (P < 0.001). Egg production was 10% with the 0.361% arginine in diet and recovered (97%) with the 1.311% arginine diet. The BL and BLq models estimated 232 mg/quail per day and 351 mg/quail per day for EO, respectively. The first intercept obtained was 290 mg/quail per day or 1,411%, which was considered the optimum level arginine intake for EO in Japanese quail.

Targeting Arginine in COVID-19-Induced Immunopathology and Vasculopathy.

Coronavirus disease 2019 (COVID-19) represents a major public health crisis that has caused the death of nearly six million people worldwide. Emerging data have identified a deficiency of circulating arginine in patients with COVID-19. Arginine is a semi-essential amino acid that serves as key regulator of immune and vascular cell function. Arginine is metabolized by nitric oxide (NO) synthase to NO which plays a pivotal role in host defense and vascular health, whereas the catabolism of arginine by arginase to ornithine contributes to immune suppression and vascular disease. Notably, arginase activity is upregulated in COVID-19 patients in a disease-dependent fashion, favoring the production of ornithine and its metabolites from arginine over the synthesis of NO. This rewiring of arginine metabolism in COVID-19 promotes immune and endothelial cell dysfunction, vascular smooth muscle cell proliferation and migration, inflammation, vasoconstriction, thrombosis, and arterial thickening, fibrosis, and stiffening, which can lead to vascular occlusion, muti-organ failure, and death. Strategies that restore the plasma concentration of arginine, inhibit arginase activity, and/or enhance the bioavailability and potency of NO represent promising therapeutic approaches that may preserve immune function and prevent the development of severe vascular disease in patients with COVID-19.

Postharvest treatment of arginine maintains the storage quality of fresh‐cut button mushrooms ( Agaricus bisporus )

Fresh-sliced button mushrooms (Agaricus bisporus) are extremely perishable and deteriorate much faster than intact fruit bodies during storage. The aim of this study was to investigate the effects of different concentrations of arginine on the storage quality of fresh-sliced A. bisporus. All the arginine treatments showed the ability to maintain the quality of fresh-cut A. bisporus. The 0.4 mM arginine treatment most effectively maintained the sensory properties of fresh-cut button mushrooms because it delayed browning and weight loss, inhibited the increase in malondialdehyde content and polyphenol oxidase (PPO) activity, and promoted the activity of peroxidase and catalase, and increased the content of total phenolic and flavonoid substances. The 0.4 mM arginine treatment also significantly lowered the expression levels of three PPO genes on day 2. These results indicate that arginine treatment has a great potential to be applied for the quality retention of fresh-sliced mushrooms during storage. Practical applications This research reveals the ability of arginine as a preservative to prolong the storage life of mushroom slices. The completion of this research also provides a new and helpful insight into the preservation approach of fresh-cut products.