Utilization Of Amino Acids Research Articles

Changes in Microbial Community Diversity and the Formation Mechanism of Flavor Metabolites in Industrial-Scale Spontaneous Fermentation of Cabernet Sauvignon Wines

The key flavor compound formation pathways resulting from indigenous microorganisms during the spontaneous fermentation of wine have not been thoroughly described. In this study, high-throughput metagenomic sequencing and untargeted metabolomics were utilized to investigate the evolution of microbial and metabolite profiles during spontaneous fermentation in industrial-scale wine production and to elucidate the formation mechanisms of key flavor compounds. Metabolome analysis showed that the total amount of esters, fatty acids, organic acids, aldehydes, terpenes, flavonoids, and non-flavonoids increased gradually during fermentation. Enrichment analysis indicated that metabolic pathways related to the synthesis, decomposition, transformation, and utilization of sugars, amino acids, and fatty acids were involved in the formation of key flavor compounds in wine. Metagenomic analysis revealed that Saccharomyces, Hanseniaspora, Zygosaccharomyces, Wickerhamiella, Lactobacillus, and Fructobacillus were the dominant taxa during spontaneous fermentation. They were significantly positively correlated with organic acids, fatty acids, esters, phenols, aldehydes, terpenes, and phenols. In conclusion, this research provides new insights into the metabolic pathways of key flavor compounds formed by indigenous microorganisms during wine fermentation.

Characterising the metabolic functionality of the preterm neonatal gut microbiome prior to the onset of necrotising enterocolitis: a pilot study

Abstract Background Necrotising enterocolitis (NEC) is a devastating bowel disease that primarily occurs in infants born prematurely and is associated with abnormal gut microbiome development. While gut microbiome compositions associated with NEC have been well studied, there is a lack of experimental work investigating microbiota functions and their associations with disease onset. The aim of this pilot study was to characterise the metabolic functionality of the preterm gut microbiome prior to the onset of NEC compared with healthy controls. Results Eight NEC infants were selected of median gestation 26.5 weeks and median day of life (DOL) of NEC onset 20, with one sample used per infant, collected within one to eight days (median four) before NEC onset. Each NEC case was matched to a control infant based on gestation and sample DOL, the main driver of microbiome composition in this population, giving a total cohort of 16 infants for this study. Dietary exposures were well matched. The microbiota of NEC and control infants showed similar wide-ranging metabolic functionalities. All 94 carbon sources were utilised to varying extents but NEC and control samples clustered separately by supervised ordination based on carbon source utilisation profiles. For a subset of eight samples (four NEC, four control) for which pre-existing metagenome data was available, microbiome composition was found to correlate significantly with metabolic activity measured on Biolog plates (p = 0.035). Comparisons across all 16 samples showed the NEC microbiota to have greater utilisation of carbon sources that are the products of proteolytic fermentation, specifically amino acids. In pairwise comparisons, L-methionine was highly utilised in NEC samples, but poorly utilised in controls (p = 0.043). Carbon sources identified as discriminatory for NEC also showed a greater enrichment for established markers of inflammatory disease, such as inflammatory bowel disease, irritable bowel syndrome and diverticular disease. Conclusions Before NEC onset, the preterm gut microbiota showed greater metabolic utilisation of amino acids, potentially indicating a shift from predominantly saccharolytic to proteolytic fermentation. Products of amino acid breakdown could therefore act as biomarkers for NEC development. A larger study is warranted, ideally with infants from multiple sites.

SUPERMAGO: Protein Function Prediction Based on Transformer Embeddings.

Recent technological advancements have enabled the experimental determination of amino acid sequences for numerous proteins. However, analyzing protein functions, which is essential for understanding their roles within cells, remains a challenging task due to the associated costs and time constraints. To address this challenge, various computational approaches have been proposed to aid in the categorization of protein functions, mainly utilizing amino acid sequences. In this study, we introduce SUPERMAGO, a method that leverages amino acid sequences to predict protein functions. Our approach employs Transformer architectures, pre-trained on protein data, to extract features from the sequences. We use multilayer perceptrons for classification and a stacking neural network to aggregate the predictions, which significantly enhances the performance of our method. We also present SUPERMAGO+, an ensemble of SUPERMAGO and DIAMOND, based on neural networks that assign different weights to each term, offering a novel weighting mechanism compared with existing methods in the literature. Additionally, we introduce SUPERMAGO+Web, a web server-compatible version of SUPERMAGO+ designed to operate with reduced computational resources. Both SUPERMAGO and SUPERMAGO+ consistently outperformed state-of-the-art approaches in our evaluations, establishing them as leading methods for this task when considering only amino acid sequence information.

Impact of feed availability on growth performance and amino acid utilization of cobia (Rachycentron canadum) at elevated temperature

IntroductionThis study explored the effects of increased water temperatures and limited feeding on the growth, feed utilization, and nutrient retention in juvenile cobia (Rachycentron canadum).MethodsJuvenile cobia, approximately 5.0 g in body weight, were distributed across two temperature conditions: 34°C, to mimic a global warming scenario, and 30°C, the current local summer average, as controls. The setup included eighteen 200-liter tanks, with 20 fish per tank. Within each temperature regime, triplicate tanks received one of three feeding levels (55%, 75%, and 95% of satiation as determined at 30°C) over a six-week period.ResultsThe findings indicated that cobia exhibited the poorest growth performance at the elevated temperature (34°C) and the lowest feeding level (55%). These conditions also correlated with the lowest protein efficiency ratio and feed intake. The feed conversion ratio worsened with increased temperature and feeding levels, while protein production values decreased at higher temperatures. A lower feeding level caused a lower total lipid retention but led to increased retention of whole body essential amino acids.DiscussionAfter six weeks, a 24-hour post-prandial analysis showed selective retention of some amino acids in muscle and plasma, but significantly higher retention in the liver at the higher temperature. Only a few amino acids' retention was influenced by feeding level. These results suggest that temperature and feeding levels alter the prioritization of amino acid metabolism and retention, as well as the utilization of energy and substrates across different organs of the cobia.

IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep.

Insulin-like growth factor-1 (IGF-1) and insulin are important fetal anabolic hormones. Complications of pregnancy, such as placental insufficiency, can lead to fetal growth restriction (FGR) with low-circulating IGF-1 and insulin concentrations and attenuated glucose-stimulated insulin secretion (GSIS), which likely contribute to neonatal glucose dysregulation. We previously demonstrated that a 1-wk infusion of IGF-1 LR3, an IGF-1 analog with low affinity for IGF-binding proteins and high affinity for the IGF-1 receptor, at 6.6 µg·kg-1·h-1 into normal fetal sheep increased body weight but lowered insulin concentrations and GSIS. In this study, FGR fetal sheep received either IGF-1 LR3 treatment at 1.17 ± 0.12 μg·kg-1·h-1 (LR3; n = 7) or vehicle (VEH; n = 7) for 1 wk. Plasma insulin, glucose, oxygen, and amino acids were measured before starting treatment and at the end of the treatment period. GSIS was measured on the final treatment day. Fetal body weights, insulin, glucose, oxygen, and GSIS were not different between groups. Amino acid concentrations decreased in LR3 (baseline vs. final individual means comparison P = 0.0232) but not in VEH (P = 0.3866). In summary, a 1-wk IGF-1 LR3 treatment did not improve growth in FGR fetuses. Insulin concentrations and GSIS were not attenuated by IGF-1 LR3, yet circulating amino acids decreased, which could reflect increased amino acid utilization. We speculate that maintaining amino acid concentrations or raising insulin, glucose, and/or oxygen concentrations to values consistent with normally growing fetuses during IGF-1 LR3 treatment may be necessary to increase fetal growth in the setting of placental insufficiency and FGR.NEW & NOTEWORTHY IGF-1 LR3 treatment administered directly into growth-restricted fetal sheep circulation did not improve fetal growth or attenuate circulating insulin or fetal GSIS. Importantly, IGF-1 LR3 treatment reduced circulating amino acids, notably branched-chain amino acids, which have been shown to potentiate GSIS and protein accretion supporting fetal growth.

Exploring Metabolic Approaches for Epithelial Ovarian Cancer Therapy.

Epithelial ovarian cancer (EOC) has the highest mortality rate among malignant tumors of the female reproductive system and the lowest survival rate. This poor prognosis is due to the aggressive nature of EOC, its late-stage diagnosis, and the tumor's ability to adapt to stressors through metabolic reprogramming. EOC cells sustain their rapid proliferation by altering the uptake, utilization, and regulation of carbohydrates, lipids, and amino acids. These metabolic changes support tumor growth and contribute to metastasis, chemotherapy resistance, and immune evasion. Targeting these metabolic vulnerabilities has shown promise in preclinical studies, with some therapies advancing to clinical trials. However, challenges remain due to tumor heterogeneity, adaptive resistance mechanisms, and the influence of the tumor microenvironment. This review provides a comprehensive summary of metabolic targets for EOC treatment and offers an overview of the current landscape of clinical trials focusing on ovarian cancer metabolism. Future efforts should prioritize combination therapies that integrate metabolic inhibitors with immunotherapies or chemotherapy. Advances in precision medicine and multi-omics approaches will be crucial for identifying patient-specific metabolic dependencies and improving outcomes. By addressing these challenges, metabolism-based therapies can significantly transform the treatment of this devastating disease.

In vitro simulated digestion and Caco-2 cell absorption to explore potential of soy protein isolates as whey protein substitutes in canine and feline food.

Digestive properties and bioavailability of soy protein isolate and whey protein in canine and feline were evaluated using in vitro simulated digestion and cell absorption experiments. The amino acids and peptides in soybean protein isolate and whey protein after digestion were detected by high-performance liquid chromatography and liquid mass spectrometry. Gastrointestinal digestion rates of soy protein isolate and whey protein were analyzed by fitting digestive kinetics curves. The degree of absorption and utilization of amino acids and peptides from the digestive products was evaluated by establishing a Caco-2 cell model. The results demonstrated that soy protein isolate, like whey protein, could produce large amounts of free amino acids and peptides distributed 100-1500 Da. The gastrointestinal digestion speed of soy protein isolate was similar with whey protein. It is worth noting from the intestinal absorption of Caco-2 cell that more than 15 amino acids produced by soy protein isolate and whey protein could be absorbed, and a large number of peptides were also utilized by Caco-2 cell. The bioavailability of soy protein isolates and whey protein for dogs respectively reached 6.30% and 9.00%, and it reached 7.40% and 16.40% in cats, respectively. Soy isolate proteins can be digested and absorbed by pets like whey proteins. These findings may provide significant strategies and support for the application of plant-based proteins in pet foods.

Distinct modulation of calcium-activated chloride channel TMEM16A by drug-binding sites

TMEM16A is a calcium-activated chloride channel with significant role in epithelial fluid secretion, sensory transduction, and smooth muscle contraction. Several TMEM16A inhibitors have been identified; however, their binding sites and inhibitory mechanisms remain unclear. Using magnolol and honokiol, the two regioisomeric inhibitors, as chemical probes, we have identified a drug-binding site distinct from the pore region, in TMEM16A, which is described here. With electrophysiology, unbiased molecular docking and clustering, molecular dynamics simulations, and experimental validation with mutant cycle analysis, we show that magnolol and honokiol utilize different drug-binding sites, pore and nonpore pockets. The pore blocker utilizes amino acids crucial for chloride passage, whereas the nonpore blocker allosterically modulates the pore residues to hinder ion permeation. Among 17 inhibitors tested, 11 were pore blockers and 6 were nonpore blockers, indicating the importance of this nonpore pocket. Our study provides insights into drug-binding mechanism in TMEM16A together with a rationale for future drug development.

Phenylalanine Regulates Milk Protein Synthesis via LAT1-mTOR Signaling Pathways in Bovine Mammary Epithelial Cells.

Phenylalanine (Phe) is a potentially limiting amino acid for lactating cows. The mechanism by which Phe regulates milk protein synthesis remains unclear. The present study elucidates the mechanisms by which phenylalanine affects milk protein synthesis, amino acid utilization, and related signaling pathways in bovine mammary epithelial cells (BMECs). The BMECs were treated with five concentrations (0, 0.22, 0.44, 0.88, 1.76 mM, and serum free). Rapamycin inhibitors and RNA interference (RNAi) were used to inhibit the phosphorylation of the mammalian target of rapamycin (mTOR) signaling pathway and the expression of relevant amino acid transporters, respectively. The results showed that 4×Phe (0.88 mM) significantly increased (p < 0.05) both the mRNA and protein expression of α-casein (CSN1S1), β-casein (CSN2), and κ-casein (CSN3), as well as L-type amino acid transporter-1 (LAT1) mRNA expression. Protein expression and modification assays of mTOR-related proteins showed that 4×Phe could increase (p < 0.05) the expression of α-casein and eukaryotic initiation factor 4E-binding protein-1 (4EBP1) and tended to increase the expression of ribosomal protein S6 protein kinase (S6K1, p = 0.054). The general control nonderepressible 2 (GCN2) signaling pathway factor, eukaryotic initiation factor 2 (eIF2α), was downregulated by 4×Phe treatment (p < 0.05). The rapamycin inhibition test showed that Phe regulated casein synthesis via the mTOR signaling pathway. RNAi experiments showed that LAT1 mediated the entry of Phe into cells. Moreover, 4×Phe treatment tended to decrease (0.05 < p < 0.10) the consumption of valine, leucine, histidine, tyrosine, cysteine, alanine, asparagine, and serine in the medium. Collectively, phenylalanine enhanced α-casein synthesis by regulating the phosphorylation of 4EBP1 and eIF2α and promoting the formation of the mTOR-centered casein translation initiation complex.

Molecular dynamics-based computational investigations on the influence of tumor suppressor p53 binding protein against other proteins/peptides

The tumor-suppressing p-53 binding protein is a crucial protein that is involved in the prevention of cancer via its regulatory effect on a number of cellular processes. Recent evidence indicates that it interacts with a number of other proteins involved in cancer in ways that are not fully understood. An understanding of such interactions could provide insights into novel ways p53 further exerts its tumour prevention role via its interactions with diverse proteins. Thus, this study aimed to examine the interactions of the p53 protein with other proteins (peptides and histones) using molecular simulation dynamics. We opted for a total of seven proteins, namely 2LVM, 2MWO, 2MWP, 4CRI, 4 × 34, 5Z78, and 6MYO (control), and had their PBD files retrieved from the protein database. These proteins were then docked against the p-53 protein and the resulting interactions were examined using molecular docking simulations run at 500 ns. The result of the interactions revealed the utilisation of various amino acids in the process. The peptide that interacted with the highest number of amino acids was 5Z78 and these were Lys10, Gly21, Trp24, Pro105, His106, and Arg107, indicating a stronger interaction. The RMSD and RMSF values indicate that the complexes formed were stable, with 4CRI, 6MYO, and 2G3R giving the most stable values (less than 2.5 Å). Other parameters, including the SASA, Rg, and number of hydrogen bonds, all indicated the formation of fairly stable complexes. Our study indicates that overall, the interactions of 53BP1 with p53K370me2, p53K382me2, methylated K810 Rb, p53K381acK382me2, and tudor-interacting repair regulator protein indicated interactions that were not as strong as those with the histone protein. Thus, it could be that P53 may mediate its tumour suppressing effect via interactions with amino acids and histone.

Chromium yeast promotes milk protein synthesis by regulating ruminal microbiota and amino acid metabolites in heat-stressed dairy cows

The intensifying global warming may increase the impact of heat stress on the dairy industry. Our previous study showed that chromium yeast (CY) alleviated the negative effects of heat stress and improved the lactation performance by increasing milk protein content and yield in mid-lactation dairy cows. This study further investigated whether the increased milk protein after CY supplementation results from the promotion of microbial crude protein (MCP) synthesis by regulating rumen microorganisms and amino acid metabolites. Twelve heat-stressed dairy cows were divided into two treatment groups: one with CY supplementation (0.36 mg Cr/kg DM) and the other without CY supplementation. Samples were collected after eight weeks of formal experiment in a hot summer with the mean temperature-humidity index of 79.0 ± 3.13. Dietary CY supplementation did not affect rumen pH, total volatile fatty acid, acetate, propionate, isobutyrate, butyrate, isovalerate, and valerate, but increased ruminal MCP concentration (P < 0.05). Simultaneously, the alpha or beta diversity of rumen microbial bacteria were not influenced by CY supplementation. At genus level, supplementation with CY increased the relative abundances of Olsenella, Lachnospiraceae_UCG-002, and Shuttleworthia (P < 0.05) and decreased those of Enterobacter, Escherichia-Shigella, Oribacterium, and Bacteroidetes_BD2-2 (P < 0.05). There were 17 up-regulated and 57 down-regulated differential metabolites in the CON and CY groups. The partial least-squares discriminant analysis (PLS-DA) and orthogonal partial least-squares discriminant analysis (OPLS-DA) scores clearly distinguished the two groups. Chromium yeast supplementation reduced the concentrations of D-(+)-proline, DL-glutamic acid, DL-lysine, Gly-l-pro, L-(-)-serine, L-(+)-alanine, and L-(+)-aspartic acid (P < 0.05) in the ruminal fluid, which were involved in arginine biosynthesis (P = 0.029), glutathione metabolism (P = 0.047), lysine degradation (P = 0.069), and D-amino acid metabolism (P = 0.084). Spearman correlation analysis showed that milk protein content was positively correlated with MCP and negatively correlated with amino acid concentrations in the ruminal fluid (P < 0.05). Collectively, CY supplementation promoted the utilization of amino acids by rumen microorganisms to synthesize MCP, thereby increasing milk protein content and yield in heat-stressed dairy cows.

Different starch sources and amino acid levels on growth performance, starch and amino acids digestion, absorption and metabolism of 0- to 3-week-old broilers fed low protein diet

The synchronized absorption of amino acids and glucose in the gut is essential for amino acid utilization and protein synthesis in the body. The study aimed to investigate how the starch digestion rate and amino acid levels impact the growth and intestinal starch and amino acid digestion, transport, and metabolism in juvenile broilers. The experiment was conducted with 702 Arbor Acres Plus broilers at 1 d old, which were randomly divided into 9 treatments with 6 replicates of 13 chickens each. The treatments included 3 different starch sources (corn, waxy corn, and tapioca) with 3 different apparent ileal digestible lysine (AID Lys) levels (1.08%, 1.20%, and 1.32%). A notable interaction was noted for dietary starch sources and AID Lys levels in the feed-to-gain ratio (F/G) and distal ileal starch digestibility (P < 0.01). The tapioca starch and waxy corn starch diets with 1.32% of AID Lys significantly decreased F/G compared with corn starch (P < 0.01). There was no significant difference in F/G of broilers among waxy corn starch diet with 1.08% AID Lys level, tapioca starch diet with 1.20% AID Lys level, and corn starch diet with 1.32% AID Lys level (P > 0.05). The 1.32% AID Lys level and the waxy corn starch both improved the body weight (BW) of broilers from 0 to 3 weeks of age, intestinal starch digestibility, and intestinal villi height or the ratio of villi height to crypt depth (P < 0.05). Compared with the corn starch diet, waxy corn starch and tapioca starch diets significantly elevated the AID of Met, Glu, Lys, Arg, Asp, His, Ile, Tyr, Gly, and Val levels (P < 0.05). The carbon metabolomics results revealed that the waxy corn starch diet significantly reduced malic acid and cis-aconitic acid levels (P < 0.05) in the tricarboxylic acid cycle compared to the corn starch diet. It was concluded that a waxy corn starch diet improves the growth performance of broilers by improving intestinal morphology, increasing the absorption and transport of amino acids, reducing the amino acid oxidation for energy supply in the intestinal mucosa, and promoting protein synthesis in muscles, which not only reduces the need for dietary AID Lys but also saves on production costs.

Imprints of Soil Microbial Activity Accredited to Residue-Management and Tillage Practices for Boosting Rice and Wheat Production

The sustainable productivity of rice–wheat cropping systems relies on soil health, and soil health can be positively influenced by treating previous crop residues using conservation tillage practices. The present study examined the impact of three rice residue-management practices under zero-tilled wheat (ZTW) and conventionally tilled wheat (CTW), along with two rice-sowing practices, during rice cultivation on soil functional microbial diversity, physiological profiling, and grain yields of rice and wheat. Anchored residues (ARs) under ZTW exhibited significantly (p ≤ 0.05) high average well color development—31.43% more than CTW with no residue (NR). CTW with residue burning (BUR) showed a 5.42% increase in the Shannon diversity index compared to CTW-NR. Substrate richness was 10.02% higher in CTW-BUR compared to CTW-NR. CTW-BUR demonstrated the highest 17.98% increase in the Shannon evenness index compared to CTW-NR. The direct-seeded rice (DSR) system generally surpassed puddled transplanted rice (PTR) in most indices, except for the Shannon evenness index values. ZTW-AR exhibited the highest utilization of amino acids, carboxylic acids, and phenolic compounds, while CTW-BUR exhibited the highest utilization of carbohydrates and polymers utilization, and ZTW with no-residue (NR) exhibited the highest utilization of amines. Rice and wheat grain yields were highest with full residue in ZTW and lowest in CTW-NR. PTR supported higher rice yields, while DSR was superior for wheat. These findings highlight the favorable role of residue retention with no tillage during wheat cultivation in the maintenance of soil quality and rice–wheat productivity.

Cardiac Urea Cycle Activation by Time-Restricted Feeding Protects Against Pressure Overload-Induced Heart Failure.

Heart failure is a leading cause of mortality worldwide, necessitating the development of novel therapeutic and lifestyle interventions. Recent studies highlight a potential role of time-restricted feeding (TRF) in the prevention and treatment of cardiac diseases. Here, it is found that TRF protected against heart failure at different stages in mice. Metabolomic profiling revealed that TRF upregulated most circulating amino acids, and amino acid supplementation protected against heart failure. In contrast, TRF showed a mild effect on cardiac amino acid profile, but increased cardiac amino acid utilization and activated the cardiac urea cycle through upregulating argininosuccinate lyase (ASL) expression. Cardiac-specific ASL knockout abolished the cardioprotective effects afforded by TRF. Circulating amino acids also protected against heart failure through activation of the urea cycle. Additionally, TRF upregulated cardiac ASL expression through transcription factor Yin Yang 1, and urea cycle-derived NO contributes to TRF-afforded cardioprotection. Furthermore, arteriovenous gradients of circulating metabolites across the human hearts were measured, and found that amino acid utilization and urea cycle activity were impaired in patients with decreased cardiac function. These results suggest that TRF is a promising intervention for heart failure, and highlight the importance of urea cycle in regulation of cardiac function.

Characterization of Phytoplankton-Derived Amino Acids and Tracing the Source of Organic Carbon Using Stable Isotopes in the Amundsen Sea.

We utilized amino acid (AA) and carbon stable isotope analyses to characterize phytoplankton-derived organic matter (OM) and trace the sources of organic carbon in the Amundsen Sea. Carbon isotope ratios of particulate organic carbon (δ13C-POC) range from -28.7‱ to -23.1‱, indicating that particulate organic matter originated primarily from phytoplankton. The dissolved organic carbon isotope (δ13C-DOC) signature (-27.1 to -21.0‱) observed in the sea-ice melting system suggests that meltwater contributes to the DOC supply of the Amundsen Sea together with OM produced by phytoplankton. A negative correlation between the degradation index and δ13C-POC indicates that the quality of OM significantly influences isotopic fractionation (r2 = 0.59, p < 0.001). The AA distribution in the Amundsen Sea (5.43 ± 3.19 µM) was significantly larger than previously reported in the Southern Ocean and was associated with phytoplankton biomass (r2 = 0.49, p < 0.01). Under conditions dominated by P. antarctica (DI = 2.29 ± 2.30), OM exhibited greater lability compared to conditions co-dominated by diatoms and D. speculum (DI = 0.04 ± 3.64). These results highlight the important role of P. antarctica in influencing the properties of OM, suggesting potential impacts on carbon cycling and microbial metabolic activity in the Amundsen Sea.

Dietary superdosing of phytase positively affects growth, mineral utilization and amino acid availability of channel catfish (Ictalurus punctatus)

The present study investigated the effects of supplementing high levels (superdosing) of dietary phytase on growth performance, mineral utilization and digestibility of amino acids in different regions of the gastrointestinal (GI) tract of fingerling channel catfish. The negative control (NC) diet was formulated with primarily soybean meal as a protein feedstuff which contributed 0.61 % total phosphorus (P) but was deficient in available P at 0.11 % of diet. Five other diets were formulated either with supplemental monocalcium phosphate at 1 % of diet in the positive control (PC), or supplemented with Quantum Blue phytase (AB Vista, Plantation, Florida) at 1000, 2000, 4000, or 8000 phytase units (FTU)/kg of diet. Groups of 20 catfish were each stocked into 24 aquaria operated as a closed, recirculating system with biological and mechanical filtration. All dietary treatments were assigned randomly to quadruplicate aquaria and initially fed at 6 % of total body weight per day. Feed quantities were adjusted weekly after weighing all fish in each aquarium as a group, and feeding levels were maintained close to apparent satiation throughout the 8-week feeding trial. Phytase supplementation significantly (P < 0.05) increased various responses of channel catfish including weight gain, feed efficiency, and protein retention compared to catfish fed the NC diet, resulting in values that were similar to catfish fed the PC diet. Moreover, catfish fed the phytase-supplemented diets had higher bone ash, calcium (Ca), magnesium (Mg), P, manganese (Mn), and zinc (Zn), as well as retention of Ca, Mg, P, iron (Fe), Mn, and Zn in whole-body tissues. Additionally, apparent availability of P from the posterior intestinal region increased with dietary phytase supplementation, with reduced excretion of nitrogen, Ca, Mg, P, copper (Cu), Mn, and Zn observed in comparison to fish fed the NC diet. Apparent digestibility coefficients for many of the indispensable and dispensable amino acids were increased by phytase supplementation, except for histidine, methionine, threonine, and taurine. This improvement in amino acid availability occurred only in the posterior region of the gastrointestinal tract. Channel catfish fed the diet containing 4000 FTU/kg diet had the highest postprandial plasma phosphorus level most of the time, except at 24 h after feeding. Based on these various responses, the optimal dietary phytase dosage was determined to average 5492 FTU/kg diet.

Amino Acid–Based Block Copolymer Templates‐Dependent Enhancement of Physicochemical and Electrochemical Characteristics of Mesoporous Carbons

ABSTRACTAmino acid–based block copolymers (BCPs) have distinct features such as secondary structure formation, chirality, amphoteric nature, non‐toxicity, and biodegradability, setting them apart from other BCPs. This suggests that amino acid–based BCPs may exhibit unique self‐assembly behaviors. Despite these advantages, they have not yet been utilized as templates for mesoporous carbons (MCs) synthesis. Here, we investigate, for the first time, the effect of hydrophobicity of two different poly(ethylene glycol) (PEG) conjugated amino acid–based BCP templates (PEG‐poly(β‐benzyl‐l‐aspartate) (PEG‐PBLA) and PEG‐poly(γ‐benzyl‐l‐glutamate) (PEG‐PBLG)) on the construction of MC materials and also their physicochemical and electrochemical characteristics. MCs produced using PEG‐PBLA and PEG‐PBLG as templates are labeled CPBLA and CPBLG, respectively. Utilizing amino acid–based BCP systems enabled achieving MC materials with nearly 1 at% nitrogen doping without external nitrogen dopants. Physicochemical analysis showed CPBLA had a smaller particle size, higher specific surface area, pore size, and hydrophilicity due to increased oxygen and nitrogen contents, as well as a higher defective structure than CPBLG. The higher hydrophilicity of PEG‐PBLA led to the formation of CPBLA MC particles with smaller size and higher specific surface area of 602 m2g−1 and pore size of 7.8 nm. Cyclic voltammetry demonstrated that CPBLA had superior charge‐storing capacity (specific capacitance of 147 F g−1 at 1 mv s−1) than CPBLG, attributed to its better physicochemical properties. These promising findings suggest that amino acid–based BCP systems can serve not only as templates but also as carbon and nitrogen sources, offering potential for high‐performance electrochemical energy storage devices.

High-level L-Gln compromises intestinal amino acid utilization efficiency and inhibits protein synthesis by GCN2/eIF2α/ATF4 signaling pathway in piglets fed low-crude protein diets

Gln, one of the most abundant amino acids (AA) in the body, performs a diverse range of fundamental physiological functions. However, information about the role of dietary Gln on AA levels, transporters, protein synthesis, and underlying mechanisms in vivo is scarce. The present study aimed to explore the effects of low-crude protein diet inclusion with differential doses of L-Gln on intestinal AA levels, transporters, protein synthesis, and potential mechanisms in weaned piglets. A total of 128 healthy weaned piglets (Landrace × Yorkshire) were randomly allocated into four treatments with four replicates. Pigs in the four groups were fed a low-crude protein diet containing 0%, 1%, 2%, or 3% L-Gln for 28 d. L-Gln administration markedly (linear, P < 0.05) increased Ala, Arg, Asn, Asp, Glu, Gln, His, Ile, Lys, Met, Orn, Phe, Ser, Thr, Tyr, and Val levels and promoted trypsin activity in the jejunal content of piglets. Moreover, L-Gln treatment significantly enhanced concentrations of colonic Gln and Trp, and serum Thr (linear, P < 0.01), and quadratically increased serum Lys and Phe levels (P < 0.05), and decreased plasma Glu, Ile, and Leu levels (linear, P < 0.05). Further investigation revealed that L-Gln administration significantly upregulated Atp1a1, Slc1a5, Slc3a2, Slc6a14, Slc7a5, Slc7a7, and Slc38a1 relative expressions in the jejunum (linear, P < 0.05). Additionally, dietary supplementation with L-Gln enhanced protein abundance of general control nonderepressible 2 (GCN2, P = 0.010), phosphorylated eukaryotic initiation factor 2 subunit alpha (eIF2α, P < 0.001), and activating transcription factor 4 (ATF4) in the jejunum of piglets (P = 0.008). These results demonstrated for the first time that a low crude protein diet with high-level L-Gln inclusion exhibited side effects on piglets. Specifically, 2% and 3% L-Gln administration exceeded the intestinal utilization capacity and compromised the jejunal AA utilization efficiency, which is independent of digestive enzyme activities. A high level of L-Gln supplementation would inhibit protein synthesis by GCN2/eIF2α/ATF4 signaling in piglets fed low-protein diets, which, in turn, upregulates certain AA transporters to maintain AA homeostasis.

Value of 11C-Methionine PET Imaging in High-Grade Gliomas: A Narrative Review.

11C-Methionine (MET) is a widely utilized amino acid tracer in positron emission tomography (PET) imaging of primary brain tumors. 11C-MET PET offers valuable insights for tumor classification, facilitates treatment planning, and aids in monitoring therapeutic response. Its tracer properties allow better delineation of the active tumor volume, even in regions that show no contrast enhancement on conventional magnetic resonance imaging (MRI). This review focuses on the role of MET-PET in brain glioma imaging. The introduction provides a brief clinical overview of the problems of high-grade and recurrent gliomas. It discusses glioma management, radiotherapy planning, and the difficulties of imaging after chemoradiotherapy (pseudoprogression or radionecrosis). The mechanism of MET-PET is described. Additionally, the review encompasses the application of MET-PET in the context of primary gliomas, addressing its diagnostic precision, utility in tumor classification, prognostic value, and role in guiding biopsy procedures and radiotherapy planning.

Haemonchus contortus alters distribution and utilization of protein and amino acids in different tissues of host sheep

The objective was to determine host animal protein/amino acid redistribution and use among the abomasum, duodenum and muscle of sheep infected with Haemonchus contortus. Sixteen male Ujumqin sheep (32.4 ± 3.9 kg) were dewormed and randomly assigned to two groups, infected or not infected with H. contortus (GIN and CON). The GIN group had lower (P < 0.05) dry matter intake, average daily gain, and live body weight than CON, with extensive focal infiltration of lymphocytes in the lamina propria and bottom of the abomasal epithelium. In the abomasum and duodenum, there were 100 and 220 genes, respectively, that were up-regulated, whereas 56 and 149 were down-regulated. In the abomasum, the most enriched KEGG pathways were related to immunity and inflammation reaction, including: viral protein interaction with cytokine and cytokine receptor (P = 0.017), influenza A (P = 0.030), IL-17 signaling pathway (P = 0.030). In the duodenum, KEGG pathways were more enriched in nutrient metabolism, including pancreatic secretion (P < 0.001), protein digestion and absorption (P < 0.001), graft-versus-host disease (P = 0.004). Furthermore, most genes related with the above KEGG pathways were increased in the abomasum but decreased in the duodenum. Amino acid profiles in abomasum and duodenum of CON and GIN groups were clustered in a partial least-squares discriminant analysis model, with significant changes in 36 and 19 metabolites in abomasal and duodenal chyme, respectively. Further confirmed by transcriptome-targeted metabolome association analysis, GIN mainly enhanced metabolism of arginine and sulphur amino acids in abomasum and those metabolic pathways were associated. Meanwhile, GIN mainly decreased pyruvate related amino acid metabolism in duodenum. Moreover, concentrations of Arg (P = 0.036), His (P = 0.027), and Cys (P = 0.046) in longissimus thoracis et lumborum were decreased in GIN, whereas concentrations of Gly (P = 0.012) and Ala (P = 0.046) were increased. In conclusion, H. contortus enhanced metabolism of arginine and sulphur amino acids in the abomasum; decreased pyruvate metabolism in the duodenum; and drove more protein/amino acids for abomasal tissues to resist physical and immune damage, reducing protein and amino acids in duodenum and muscle for support host growth. Specific nutrients (such like arginine, histidine, and cysteine) may play important role in control gastrointestinal nematode infection for ruminant.