Amino Acid Oxidation Research Articles

Minimum methionine requirement in adult cats as determined by indicator amino acid oxidation.

There is a lack of empirical data on the dietary Met requirement, in the presence of Cys or cystine, in adult cats. Thus, the aim of this study was to determine the Met requirement, in the presence of excess Cys, in adult cats at maintenance using the indicator amino acid oxidation (IAAO) technique. Six adult neutered male cats were initially selected and started the study. Cats were adapted to the basal diet sufficient in Met (0.24% dry matter, DM) for 14 d prior to being randomly allocated to one of eight dietary levels of Met (0.10%, 0.13%, 0.17%, 0.22%, 0.27%, 0.33%, 0.38%, and 0.43% DM). Different dietary Met concentrations were achieved by supplementing the basal diet with Met solutions. Alanine was additionally included in the solutions to produce isonitrogenous and isoenergetic diets. Cats underwent a 2-d adaptation period to each experimental diet prior to each IAAO study day. On IAAO study days, 13 meals were offered corresponding to 75% of each cat's daily food allowance. The remaining 25% of their daily food intake was offered after each IAAO study. A bolus dose of NaH13CO3 (0.44mg kg-1) and l-[1-13C]-phenylalanine (13C-Phe; 4.8mg kg-1) were provided in fifth and sixth meals, respectively, followed by a constant dose of 13C-Phe (1.04mg kg-1) in the next meals. Breath samples were collected and total production of 13CO2 was measured every 25min through respiration calorimetry chambers. Steady state of 13CO2 achieved over at least three breath collections was used to calculate oxidation of 13C-Phe (F13CO2). Competing models were applied using the NLMIXED procedure in SAS to determine the effects of dietary Met on 13CO2. Two cats were removed from the study as they did not eat all meals, which is required to achieve isotopic steady. A breakpoint for the mean Met requirement, with excess of Cys, was identified at 0.24% DM (22.63mg kg-1) with an upper 95% confidence limit of 0.40% DM (37.71 mg·kg-1), on an energy density of 4,164 kcal of metabolizable energy/kg DM calculated using the modified Atwater factors. The estimated Met requirement, in the presence of excess of Cys, is higher than the current recommendations proposed by the National Research Council's Nutrient Requirement of Dogs and Cats, the Association of American Feed Control Officials, and the European Pet Food Industry Federation.

The anabolic response to protein ingestion during recovery from exercise has no upper limit in magnitude and duration in vivo in humans

The belief that the anabolic response to feeding during postexercise recovery is transient and has an upper limit and that excess amino acids are being oxidized lacks scientific proof. Using a comprehensive quadruple isotope tracer feeding-infusion approach, we show that the ingestion of 100g protein results in a greater and more prolonged (>12 h) anabolic response when compared to the ingestion of 25g protein. We demonstrate a dose-response increase in dietary-protein-derived plasma amino acid availability and subsequent incorporation into muscle protein. Ingestion of a large bolus of protein further increases whole-body protein net balance, mixed-muscle, myofibrillar, muscle connective, and plasma protein synthesis rates. Protein ingestion has a negligible impact on whole-body protein breakdown rates or amino acid oxidation rates. These findings demonstrate that the magnitude and duration of the anabolic response to protein ingestion is not restricted and has previously been underestimated invivo in humans.

A hypothesis about the influence of oxidative stress on amino acid protein composition during evolution

Life emerged in an anoxic world, but the release of molecular oxygen, the by-product of photosynthesis, forced adaptive changes to counteract its toxicity. However, reactive oxygen species can damage all cellular components, including proteins. Therefore, several mechanisms have evolved to balance the intracellular redox state and maintain a reductive environment more compatible with many essential biological functions. In this study, we statistically interrogated the amino acid composition of E. coli proteins to investigate how the proneness or susceptibility to oxidation of amino acids biased their sequences. By sorting the proteins into five compartments (cytoplasm, internal membrane, periplasm, outer membrane, and extracellular), we found that various oxidative lesions constrain protein composition and depend on the cellular compartments, impacting the evenness of distribution or frequency. Our findings suggest that oxidative susceptibility could influence the observed differences in amino acid abundance across cellular compartments. This result reflects how the oxidative atmosphere could restrict protein amino acid composition and impose a codon bias trend.

Menstrual Cycle Tracking in Sports Research: Challenges, Progress, and Future Directions

The roles of 17β estradiol (E2) and progesterone (P4), the primary female sex hormones, are pivotal in regulating various aspects of metabolism. E2 influences food intake, energy expenditure, adipose tissue distribution, and insulin sensitivity across multiple tissues. Meanwhile, P4 impacts energy expenditure, electrolyte balance, amino acid oxidation, muscle protein synthesis, and glucose metabolism. The interactions between these hormones affect macronutrient utilization, both at rest and during exercise. Acknowledging the need to incorporate sex hormone perturbations in research, this paper explores the current landscape of study design and menstrual cycle tracking for female-specific sport research. It emphasizes the importance of standardization in terminology, hormone phases, reference values, and affordable hormone detection methods to advance our understanding of how the menstrual cycle influences female athletes.

Protein intake affects erythrocyte glutathione synthesis in young healthy adults in a repeated-measures trial

BackgroundIn 2005, the Institute of Medicine advised using methods other than nitrogen balance (NB) for determining protein requirements. Since then, protein requirements using indicator amino acid oxidation (IAAO) have been published and are higher than NB. Glutathione (GSH), a tripeptide of cysteine, glutamate, and glycine, is a principal antioxidant that can be used as a functional indicator of protein adequacy. ObjectivesThe aim of this study was to measure changes in erythrocyte GSH kinetics [fractional synthesis rate (FSR) and absolute synthesis rate (ASR)] in healthy adults following a range of protein intakes at and above the current recommendations. MethodsSixteen healthy adults [8 males and 8 females, aged 25.6 ± 0.9 y (mean ± SEM)] were studied at 4 of 6 protein intakes ranging from 0.6 to 1.5 g⋅kg-1⋅d-1. Erythrocyte GSH kinetics were assessed during a 7-h infusion of [U-13C2–15N]glycine following 2 d of adaptation to each protein intake. Blood and urine tests were performed to measure oxidative stress markers, plasma homocysteine, triglycerides, plasma amino acid concentrations, 5-L-oxoproline (5-OP), and urinary sulfate. The protein intake that maximized GSH synthesis was determined using mixed-effect change-point regression in R. Primary and secondary outcomes were analyzed using linear mixed-effects and repeated-measures analysis of variance with Tukey’s post hoc test. ResultsThe protein intake that maximized GSH FSR at 78%⋅d-1 was 1.0 g⋅kg-1⋅d-1 (95% confidence interval: 0.63, 1.39). GSH ASR was significantly lower at 0.6 and 0.8 g⋅kg-1⋅d-1 than at 1.5 g⋅kg-1⋅d-1 (2.03 and 2.17, respectively, compared with 3.71 mmol⋅L-1⋅d-1). Increasing the protein intake led to increased urinary sulfate but did not affect erythrocyte GSH concentration, plasma oxidative stress markers, triglycerides, homocysteine, or 5-OP. ConclusionsA protein intake of 1.0 g⋅kg-1⋅d-1 maximized GSH synthesis, which is in agreement with earlier IAAO-derived protein requirements of 0.93 to 1.2 g⋅kg-1⋅d-1. These findings suggest that recommendations based on NB (0.66 g⋅kg-1⋅d-1) may underestimate protein needs for adequate health.This trial was registered at clinicaltrials.gov as NCT02971046.

Transcriptome Analysis Reveals the Inhibitory Effect of Cu2+ on Polyferric Sulfate Floc Reduction by Shewanella putrefaciens CN32.

Polyferric sulfate (PFS), an economical coagulant widely used for removing heavy metal contaminants from water, is susceptible to reduction and transformation by iron-reducing bacteria prevalent in sediments. However, the effect of heavy metal ions adsorbed in PFS flocs on this biological process remains unclear. According to our results, compared with other heavy metal cations (e.g., Cu2+, Cd2+, Zn2+, Ni2+, Pb2+, and Co2+), Cu2+ had a stronger inhibitory effect on PFS floc reduction by Shewanella putrefaciens CN32, a typical dissimilatory iron-reducing bacterium. The presence of Cu2+ remarkably influenced the global transcription of CN32, resulting in 782 upregulated genes and 713 downregulated genes that are mainly annotated in energy production, amino acid metabolism, protein biosynthesis, and oxidation‒reduction processes. The anaerobic TCA cycle for energy (electron) production was significantly activated in the presence of Cu2+, while the transcription of many genes related to the extracellular electron transfer pathway was downregulated, which is responsible for the decreased Fe3+ reduction. Moreover, the pathways of assimilatory sulfate reduction and subsequent cysteine biosynthesis were significantly enriched, which is hypothesized to result in the consumption of abundant energy produced from the enhanced anaerobic TCA cycle, revealing a strategy to address the oxidative stress caused by Cu2+. This work elucidates the unusual suppressive effects of Cu2+ on the microbial reduction of PFS flocs, which reveals the high resistance of PFS flocs to microbial destruction when used to treat Cu2+ pollution in water, thus demonstrating their tremendous practical prospects.

Reducing branched-chain amino acids improves cardiac stress response in mice by decreasing histone H3K23 propionylation.

Identification of branched-chain amino acid (BCAA) oxidation enzymes in the nucleus led us to predict that they are a source of the propionyl-CoA that is utilized for histone propionylation and, thereby, regulate gene expression. To investigate the effects of BCAAs on the development of cardiac hypertrophy and failure, we applied pressure overload on the heart in mice maintained on a diet with standard levels of BCAAs (BCAA control) versus a BCAA-free diet. The former was associated with an increase in histone H3K23-propionyl (H3K23Pr) at the promoters of upregulated genes (e.g., cell signaling and extracellular matrix genes) and a decrease at the promoters of downregulated genes (e.g., electron transfer complex [ETC I-V] and metabolic genes). Intriguingly, the BCAA-free diet tempered the increases in promoter H3K23Pr, thus reducing collagen gene expression and fibrosis during cardiac hypertrophy. Conversely, the BCAA-free diet inhibited the reductions in promoter H3K23Pr and abolished the downregulation of ETC I-V subunits, enhanced mitochondrial respiration, and curbed the progression of cardiac hypertrophy. Thus, lowering the intake of BCAAs reduced pressure overload-induced changes in histone propionylation-dependent gene expression in the heart, which retarded the development of cardiomyopathy.

The influence of rolling pressure on the changes in non-volatile compounds and sensory quality of congou black tea: The combination of metabolomics, E-tongue, and chromatic differences analyses

Rolling represents an essential stage in congou black tea processing. However, the influence of rolling pressure on tea flavor and non-volatile compounds remains unclear. Herein, a combination of untargeted metabolomics, tea pigments quantification, E-tongue, colorimeter and sensory evaluation was used to evaluate the effect of rolling pressure on black tea quality. As the rolling pressure increased, theaflavins (TFs), thearubigins (TRs), and theabrownins (TBs) significantly elevated. The tea metabolic profiles fluctuated and 47 metabolites were identified as key differential metabolites including flavan-3-ols, flavonol/flavone glycosides, phenolic acids, amino acids. These substances altered possibly due to the variations in enzymatic oxidation of tea phenolics and amino acids. Overall, black tea with moderate rolling pressure presented higher sweetness, lower bitterness, and higher quality index (10 TFs + TRs)/TBs. The results were verified by a validation batch. This study provided new insights into the regulation of rolling pressure and a guidance for black tea processing.

PSX-7 Determination of Tryptophan Requirements of Adult and Senior Labrador Retrievers Using the Indicator Amino Acid Oxidation Technique

Abstract Nutritional requirements vary across the life stages of canines, and the consumer demand for advanced diets that meet the age-appropriate needs of their pets has steadily increased. Availability of veterinary care and high-quality nutrition has led to a longer average lifespan in companion animals, and although senior dogs represent a significant proportion of the pet population, few studies have targeted the specific amino acid requirements of the aging canine. In this study, the indicator amino acid oxidation (IAAO) technique was used to compare the tryptophan (Trp) requirements of young adult and senior Labrador retrievers. After 2-day adaptation to Trp-adequate basal diet (Trp = 0.256% dry matter), dogs underwent individual IAOO studies. In brief, all dogs were randomly fed one of six test diets with varying levels of tryptophan ranging from deficient to sufficient (final Trp content in experimental diets was 0.05, 0.1, 0.15, 0.224, 0.25 and 0.256% dry matter). Test diet was divided into 13 equal meals; at the 5th meal, a tracer amino acid was supplied (a bolus L-[1-13C] Phe based on body weight was first given, followed by [1-13C] Phe doses every thirty minutes spanning a four-hour period), and breath samples were collected via respiration mask every 30 minutes. Total production of 13CO2 during isotopic steady state was determined by enrichment of 13CO2 in breath samples and total CO2 production measured via indirect calorimetry and isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using segmented linear regression. The Four Rivers mean and population requirements for tryptophan were 377.7 ± 31.9 mg/1,000 kcal ME (mean ± 2SD) in the young adults and 362.9 ± 31.5 mg/1,000 kcal ME for senior dogs, which are greater than the currently recommended amounts by NRC and AAFCO. As the pet food industry offers more specialized diets for aging canines, updating the amino acid requirements for such animals is increasingly important.

62 Sulphur Amino Acids: Assessing Requirements and Utilization in Dogs and Cats

Abstract Methionine (Met), cyst(e)ine (Cys), homocysteine and taurine are the four sulfur-containing amino acids. Met can serve as a substrate for protein synthesis or to produce homocysteine, which can be remethylated to Met or irreversibly catabolized to Cys. Unlike dogs, cats are unable to further metabolize Cys to taurine, making the latter an indispensable amino acid for the cat. Met, on the other hand, is a dietary indispensable amino acid for all mammals with Cys having the ability to spare part of the Met requirement (total sulfur amino acid requirement; Met + Cys). The amount of Met that cannot be replaced by Cys is defined as the Met requirement (NRC, 2006). Empirical determinations of the Met requirement in adult dogs and cats are still limited and the recommendations proposed by the NRC (2006) are based on studies that used insensitive techniques for mature animals. When a more robust technique, the indicator amino acid oxidation, and more practical experimental diets were used to empirically determine the Met requirement, a greater estimate was found in adult cats (Pezzali et al., 2022) and adult Labrador Retrievers and Beagles, but not in miniature Dachshunds (Mansilla et al., 2020), compared with the current recommendations proposed by the NRC (2006) and AAFCO (2023). Harrison et al. (2020), however, found a decreased estimate for the Met requirement in adult Labrador Retrievers compared with Mansilla et al. (2020), likely due to differences in experimental design and diet composition. This discrepancy highlights the need to standardize methodologies and to investigate the effect of other dietary factors on the Met and total sulfur amino acid requirements owing to their complex metabolism. Indeed, the metabolism of sulfur amino acids may differ between dog breeds, resulting in differences in Met requirements and potentially making taurine a conditionally indispensable amino acid in some breeds under specific dietary conditions. While dietary Met is usually provided in excess in commercial diets, excess of Met may lead to hyperhomocysteinemia, which has been associated with detrimental health effects in other species. Due to the complex metabolism of sulfur amino acids and the complex matrix of pet foods, determining the ideal provision of sulfur amino acids in commercial diets to maximize animal health is a challenge. More long-term studies investigating the effect of different doses and ratios (Met:Cys) of sulfur amino acids on overall metabolism are necessary, in addition to requirement studies, to optimize the dietary delivery of sulfur amino acids in dogs and cats.

Consideration of utilizable amino acid content in the context of dietary protein quality assessment

AbstractCurrent evaluation systems for protein quality focus only on indispensable amino acids (IAAs) and do not consider the dispensable amino acids (DAAs). However, at excess levels of IAAs, DAAs may become limiting. Here, we used published ileal amino acid digestibility data determined in growing pigs and currently assumed protein and IAA recommendations to estimate utilizable, oxidized, and non‐absorbed amino acids in different dietary protein and to compare these utilizable amino acid values to digestible indispensable amino acid score (DIAAS) values. For dietary protein sources with a DIAAS value <90, the amount of calculated utilizable amino acids increased proportionally with the DIAAS value according to “utilizable amino acids (mg/g protein) = DIAAS × 10”; for dietary protein sources with a DIAAS value >90, the amount of utilizable amino acid stays within the range 800–1000 mg/g protein. Cereals contained the lowest levels of utilizable amino acids and the highest amount of oxidized amino acids. Dairy and meat have the highest amount of utilizable amino acids followed by nuts and pulses. For many mixtures of protein sources, the highest value for utilizable amino acids, which considers both IAAs and DAAs, occurred at a different ratio of protein sources than the maximum DIAAS value, which only considers IAAs. From this theoretical study and based on the assumptions made, we conclude that estimation of utilizable amino acids from data typically reported in DIAAS studies further enables complementary insights next to DIAAS values. Careful consideration of protein and IAA requirements is critical in further work.

Dietary protein recommendations to support healthy muscle ageing in the 21st Century and beyond: considerations and future directions.

This review explores the evolution of dietary protein intake requirements and recommendations, with a focus on skeletal muscle remodelling to support healthy ageing based on presentations at the 2023 Nutrition Society summer conference. In this review, we describe the role of dietary protein for metabolic health and ageing muscle, explain the origins of protein and amino acid (AA) requirements and discuss current recommendations for dietary protein intake, which currently sits at about 0⋅8 g/kg/d. We also critique existing (e.g. nitrogen balance) and contemporary (e.g. indicator AA oxidation) methods to determine protein/AA intake requirements and suggest that existing methods may underestimate requirements, with more contemporary assessments indicating protein recommendations may need to be increased to >1⋅0 g/kg/d. One example of evolution in dietary protein guidance is the transition from protein requirements to recommendations. Hence, we discuss the refinement of protein/AA requirements for skeletal muscle maintenance with advanced age beyond simply the dose (e.g. source, type, quality, timing, pattern, nutrient co-ingestion) and explore the efficacy and sustainability of alternative protein sources beyond animal-based proteins to facilitate skeletal muscle remodelling in older age. We conclude that, whilst a growing body of research has demonstrated that animal-free protein sources can effectively stimulate and support muscle remodelling in a manner that is comparable to animal-based proteins, food systems need to sustainably provide a diversity of both plant and animal source foods, not least for their protein content but other vital nutrients. Finally, we propose some priority research directions for the field of protein nutrition and healthy ageing.

Changes in toxicity after mixing imidacloprid and cadmium: enhanced, diminished, or both? From a perspective of oxidative stress, lipid metabolism, and amino acid metabolism in mice.

Imidacloprid (IMI) and cadmium (Cd) are pollutants of concern in the environment. Although investigations about their combined toxicity to organisms such as earthworms, aquatic worms, Daphnia magna, and zebrafish have been carried out, their combined toxicity to mammals remains unknow. In this study, twenty-four 8-week-old mice were arbitrarily separated into 4 groups: CK (control group), IMI (15 mg/kg bw/day, 1/10 LD50), Cd (15 mg/kg bw/day, 1/10 LD50), and IMI + Cd (15 mg/kg bw/day IMI + 15 mg/kg bw/d Cd) and the combined toxic effects of IMI and Cd were examined with biochemical (oxidative stress testing) and omics approaches (metabolomics and lipidomics). The results revealed changes in each treatment group in terms of oxidative stress, abnormalities in lipid metabolism, and disturbances in amino acid metabolism. Co-administration had antagonistic effects on MDA accumulation and lipid metabolism disorders while acting synergistically on changes in SOD and GSH-Px activities. It is worth noting that after analysis, the changes caused by mixed administration in vivo were closer to those caused by IMI administration alone. This study provides new insights into the combined toxicity of neonicotinoids and heavy metals, which is helpful for relevant environmental governance and further investigations about their impacts on human health and the environment.

The Minimum Methionine Requirement for Adults Aged ≥60 Years Is the Same in Males and Females.

The minimum methionine requirement in the presence of excess dietary cysteine has not been determined in older adults. This study aimed to determine the minimum methionine requirement in healthy older adults using the indicator amino acid oxidation (IAAO) method. Fifteen healthy adults ≥ 60 years of age received seven methionine intakes (0 to 20 mg/kg/d) plus excess dietary cysteine (40 mg/kg/d). Oxidation of the indicator, L-[1-13C]phenylalanine (F13CO2), was used to estimate the mean minimum methionine requirement using a change-point mixed-effect model. There was no statistical difference between male and female requirement estimates, so the data were pooled to generate a mean of 5.1 mg/kg/d (Rm2 = 0.46, Rc2 = 0.77; p < 0.01; 95% CI: 3.67, 6.53 mg/kg/d). This is the first study to estimate the minimum methionine requirement in healthy older adults, which is the same between the sexes and as our lab's previous estimate in young adults. The findings are relevant considering current recommendations for increased consumption of plant foods, which will help to establish the appropriate balance of methionine and cysteine intake required to satisfy the sulphur amino acid requirements of older adults.

Liver and Muscle Transcriptomes Differ in Mid-Lactation Cows Divergent in Feed Efficiency in the Presence or Absence of Supplemental Rumen-Protected Choline.

Improving dairy cow feed efficiency is critical to the sustainability and profitability of dairy production, yet the underlying mechanisms that contribute to individual cow variation in feed efficiency are not fully understood. The objectives of this study were to (1) identify genes and associated pathways that are altered in cows with high- or low-residual feed intake (RFI) using RNA sequencing, and (2) determine if rumen-protected choline supplementation during mid-lactation would influence performance or feed efficiency. Mid-lactation (134 ± 20 days in milk) multiparous Holstein cows were randomly assigned to either supplementation of 0 g/d supplementation (CTL; n = 32) or 30 g/d of a rumen-protected choline product (RPC; 13.2 g choline ion; n = 32; Balchem Corp., New Hampton, NY, USA). Residual feed intake was determined as dry matter intake regressed on milk energy output, days in milk, body weight change, metabolic body weight, and dietary treatment. The 12 cows with the highest RFI (low feed efficient; LE) and 12 cows with the lowest RFI (high feed efficient; HE), balanced by dietary treatment, were selected for blood, liver, and muscle analysis. No differences in production or feed efficiency were detected with RPC supplementation, although albumin was greater and arachidonic acid tended to be greater in RPC cows. Concentrations of β-hydroxybutyrate were greater in HE cows. Between HE and LE, 268 and 315 differentially expressed genes in liver and muscle tissue, respectively, were identified through RNA sequencing. Pathway analysis indicated differences in cell cycling, oxidative stress, and immunity in liver and differences in glucose and fatty acid pathways in muscle. The current work indicates that unique differences in liver and muscle post-absorptive nutrient metabolism contribute to sources of variation in feed efficiency and that differences in amino acid and fatty acid oxidation, cell cycling, and immune function should be further examined.

Metabolite profiling and transcriptomic analyses demonstrate the effects of biocontrol agents on alkaloid accumulation in Fritillaria thunbergii

BackgroundDuring Fritillaria thunbergii planting, pests and diseases usually invade the plant, resulting in reduced yield and quality. Previous studies have demonstrated that using biocontrol agents can effectively control grubs and affect the steroid alkaloids content in F. thunbergii. However, the molecular regulatory mechanisms underlying the differences in the accumulation of steroid alkaloids in response to biocontrol agents remain unclear.ResultsCombined transcriptomic and metabolic analyses were performed by treating the bulbs of F. thunbergii treated with biocontrol agents during planting. Otherwise, 48 alkaloids including 32 steroid alkaloids, 6 indole alkaloids, 2 scopolamine-type alkaloids, 1 isoquinoline alkaloid, 1 furoquinoline alkaloid, and 6 other alkaloids were identified. The content of steroidal alkaloids particularly peimine, peiminine, and veratramine, increased significantly in the group treated with the biocontrol agents. Transcriptome sequencing identified 929 differential genes using biocontrol agents, including 589 upregulated and 340 downregulated genes. Putative biosynthesis networks of steroid alkaloids have been established and combined with differentially expressed structural unigenes, such as acetyl-CoA C-acetyl-transferase, acelyl-CoAC-acetyltransferase3-hydroxy-3-methylglutaryl-coenzyme A synthase, 1-deoxy-D-xylulose-5-phosphate reductor-isomerase, 2-C-methyl-D-erythritol-4-phosphate cytidylyltransferase and 4-hydroxy-3-methylbut-2-enyl diphosphate reductase. In addition, biological processes such as amino acid accumulation and oxidative phosphorylation were predicted to be related to the synthesis of steroid alkaloids. Cytochrome P450 enzymes also play crucial roles in the steroid alkaloid synthesis. The transcription factor families MYB and bHLH were significantly upregulated after using biocontrol agents.ConclusionsBiocontrol agents increased the steroid alkaloids accumulation of steroid alkaloids by affecting key enzymes in the steroid alkaloid synthesis pathway, biological processes of oxidative phosphorylation and amino acid synthesis, cytochrome P450 enzymes, and transcription factors. This study revealed the mechanism underlying the difference in steroidal alkaloids in F. thunbergii after using biocontrol agents, laying the groundwork for future industrial production of steroid alkaloids and ecological planting of medicinal materials in the future.

Emerging Role of Ferroptosis in Breast Cancer: Characteristics, Therapy, and Translational Implications for the Present and Future.

Ferroptosis is a nonapoptotic, iron-dependent form of cell death that can be actuated in disease cells by expected improvements and manufactured specialists. Different studies have recently resurrected the role of this newly discovered cell death pathway and demonstrated its efficacy in treating breast cancer. Breast cancer is the most well-known type of cancer among women worldwide. Despite many years of research focusing on cell death in breast cancer, counting apoptosis, clinical treatment leftovers are difficult due to the high likelihood of recurrence. Ferroptosis is defined by a lack of lipid peroxide repair capacity by phospholipid hydroperoxides GPX4, accessibility of redox-active iron, and followed oxidation of polyunsaturated fatty acids acid-containing phospholipids signalling, amino acid and iron metabolism, ferritinophagy, epithelial-tomesenchymal transition, cell adhesion, and mevalonate and phospholipid biosynthesis can all be factors that influence ferroptosis susceptibility. Ferroptosis, an iron-dependent controlled cell death caused by excessive lipid peroxidation, has been entwined in breast cancer development and therapeutic response for the past decade. Advances in enhancing clinical drugs targeting ferroptosis are developing silver linings to treat breast cancer. Ferroptosis is influenced by metabolism and the expression of certain genes, making it a prospective therapeutic target for monitoring malignant growth and an appealing target for precision cancer medication disclosure. In the coming years, research into biomarkers to follow ferroptosis in patients with breast cancer and the course of events and the subsequent use of novel ferroptosis-based treatments will be captious. We present a fundamental analysis of the actual understanding of molecular mechanisms along with regulatory networks associated with ferroptosis, expected physiological functions in growth concealment, ferroptosis-associated differentially expressed genes, treatment targeting potential, and recent advances in the development of therapeutic strategies in this review.

Asparagine and nitric oxide jointly enhance antioxidant capacity and nitrogen metabolism to improve drought resistance in cotton: Evidence from long‐term field trials

AbstractAsparagine (Asn) and nitric oxide (NO) can enhance plant tolerance to abiotic stress, but their interaction is not well understood. Cotton is a vital resource for the textile industry, but its yield is reduced by drought stress, which could threaten its global supply in a warming and stressful world. Improving cotton's drought tolerance is crucial for supporting the textile industry. Two simultaneous field experiments were conducted to study the effect of Asn and sodium nitroprusside (SNP), a NO donor, on cotton's drought tolerance. Two irrigation treatments were applied: control (C: 100% A pan) and drought stress (50% A pan). The plants were also sprayed with two plant stimulants before imposing drought stress: Mock control, 20 mM Asn, and 0.2 mM SNP, either alone or together. Drought stress impaired plant growth, photosynthesis, yield, nitrogen metabolism, and antioxidant defense, while increasing oxidative stress and free amino acid levels. However, Asn and SNP treatments alleviated these negative effects and improved antioxidant enzyme activity, plant growth, yield, and nitrogen content. The Asn + SNP treatment also increased irrigation water productivity under water‐limited conditions, suggesting its potential for enhancing water use efficiency in cotton production. The combined treatment was more effective than the single treatments, indicating a synergistic effect of Asn and SNP in enhancing drought tolerance in cotton. These results imply that Asn and SNP could be useful tools for sustaining cotton production under drought conditions by boosting nitrogen metabolism and antioxidant defense, thereby contributing to the global supply of cotton and supporting the textile industry.

Evaluation of protein requirements using the indicator amino acid oxidation method: a scoping review

BackgroundThe indicator amino acid oxidation (IAAO) method has been accepted as an approach to evaluate habitual protein requirements under free-living conditions. ObjectivesThis scoping review reports on literature that evaluated protein requirements in humans using the IAAO methods. MethodsThree databases (PubMed/Medline, Web of Science, and ProQuest) were systematically searched to identify studies that evaluated protein requirements using the IAAO method published in English until 5 June, 2023. We evaluated the study quality using previously developed criteria. We extracted the characteristics of the study design and the results of protein requirements. Two reviewers conducted both reviews and quality assessments independently; any differences among them were resolved by consensus or agreement of all team members. ResultsWe extracted 16 articles targeting children, young adults (including pregnant women, resistance training athletes, endurance-training athletes, and team sports), and older adults. In quality assessment, 14 studies were evaluated “strong,” but the remaining 2 were “moderate.” These studies were conducted in only 3 countries and did not include all sexes or life stages. The range of the estimated average protein requirements of each life stage was 1.30 g/kg body weight/d for children, 0.87 to 2.10 (0.87–0.93 for general young adults, 1.22–1.52 for pregnant women, 1.49–2.00 for resistance-trained athletes, 1.65–2.10 for endurance athletes, and 1.20–1.41 for team sports athletes) g/kg body weight/d for young adults, and 0.85 to 0.96 g/kg body weight/d for older adults. ConclusionsProtein requirements in 14 studies were higher than the current reference for each sex, life stage, and physical activity that are related to protein requirements. In the future, protein requirements of various populations including sex and life stage could be assessed using the IAAO methods worldwide.

Characterization of charge variants, including post-translational modifications and proteoforms, of bispecific antigen-binding protein by cation-exchange chromatography coupled to native mass spectrometry

Charge variant characterization of biologics is critical to ensure that product meets the required quality and regulatory requirements to ensure safety and efficacy of the biotherapeutic. Charge variants arise from post-translation modifications (PTMs) during upstream processing and due to enzymatic and non-enzymatic chemical reactions that occur during downstream processing and storage. Some of these modifications may impact therapeutic potency, efficacy, or immunogenicity of a biotherapeutic. The traditional workflow for characterizing charge variants that involves fraction enrichment is time-consuming and labor-intensive. This approach can be especially challenging if the product is manufactured at low concentrations (e.g., ≤2 mg/mL). Recent advances in pH-based elution for ion-exchange chromatography utilizing volatile buffers have enabled rapid native mass-spectrometry-based identification of PTMs and proteoforms associated with protein therapeutics. In this study, we develop a novel workflow to rapidly and unambiguously characterize modifications associated with a new class of biotherapeutics known as bispecific antigen-binding protein (BsABP), including low-level modifications. A cation-exchange separation was optimized using volatile buffers to provide online hyphenation for native mass spectrometry to profile modifications and proteoforms present at the native level of a biotherapeutic, such as deamidation, O-glycosylation, amino acid substitution, N-linked glycosylation and oxidation. Furthermore, a limited proteolysis method was developed to specifically inform about modifications in the different domains of the bispecific antibody. Using this approach, we could efficiently identify PTMs in unstressed, thermally and photo-stressed samples, and provide information about the impact of downstream purification in clearing out modified BsABP species. Furthermore, peptide mapping was performed to identify and confirm modifications at the amino acid residue level. The developed workflow is less time-consumable and reduces sample processing- and analysis-related artifacts compared to traditional approaches.