Amino Acid Nutrition and Metabolism in Health and Disease

Metabolic and microbial functionality during the fermentation of traditional Amaranth stems: Insights from metagenomics, flavoromics, and metabolomics

Fermented Amaranth stems is a traditional Chinese fermented vegetable known for its distinctive aroma, produced through natural microbial fermentation. However, the metabolic processes, flavor compounds, and microbial communities involved in its fermentation are not well understood. This study provides a comprehensive analysis using an integrated approach combining flavoromics, untargeted metabolomics, and metagenomics to examine the dynamic changes in metabolites and microbiota during fermentation. A total of 108 volatile organic compounds were identified, with sugar metabolism peaking on the third day of fermentation. The microbial community analysis revealed that key genera such as Pseudomonas, Acinetobacter, Pectobacterium, and Enterobacter play a significant role in flavor formation. The findings offer critical insights into the fermentation mechanisms and the production of flavor compounds, providing a foundation for optimizing fermentation processes and improving the flavor quality of fermented Amaranth stems. This research holds practical significance for enhancing food safety by controlling microbial communities during fermentation.

Induction of Chirality in MXene Nanosheets and Derived Quantum Dots: Chiral Mixed-Low-Dimensional Ti3C2Tx Biomaterials as Potential Agricultural Biostimulants for Enhancing Plant Tolerance to Different Abiotic Stresses

This work presents two advancements in the engineering design and bio-applications of emerging MXene nanosheets and derived quantum dots. First, a facile, versatile, and universal strategy is showcased for inducing the right- or left-handed chirality into the surface of titanium carbide-based MXene (Ti3C2Tx) to form stable mixed-low-dimensional chiral MXene biomaterials with enhanced aqueous colloidal dispersibility and debonding tolerance, mimicking the natural asymmetric bio-structure of most biomolecules and living organisms. In particular, Ti3C2Tx MXene nanosheets are functionalized with carboxyl-based terminals and bound feasibly with the D/L-cysteine amino acid ligands. The physicochemical characterizations of these 2D-0D/1D chiral MXene heterostructures suggest the inclusion of Ti3C2Tx nanosheets and different levels of self-derived MXene quantum dots and surface titanium-oxide nanoparticles, providing enhanced material stability and oxidative degradation resistance for tested months. Further, the interaction and molecular binding at cysteine-Ti3C2Tx/Ti-oxide interfaces, associated ion transport and ionic conductivity analysis, and charge re/distribution mechanisms are evaluated using density functional theory (DFT) calculations and electrochemical impedance spectroscopy (EIS) measurements. The second uniqueness of this study relies on the multifunctional application of optimal chiral MXenes as potential nano-biostimulants for enhancing plant tolerance to different abiotic conditions, including severe drought, salinity, or light stress. This surface tailoring enables high biocompatibility with the seed/seedling/plant of Arabidopsis thaliana alongside promoting multi-bioactivities for enhanced seed-to-seedling transition, seedling germination/maturation, plant-induced stomatal closure, and ROS production eliciting responses. Given that the induced chirality is a pivotal factor in many agro-stimulants and amino acid-containing fertilizers for enhanced interaction with plant cells/enzymes, boosting stress tolerance, nutrient uptake, and growth, these findings open up new avenues toward multiple applications of chiral MXene biomaterials as next-generation carbon-based nano-biostimulants in agriculture.

Effectiveness of a bacteriophage YZU_PF006 in controlling dairy spoilage caused by Pseudomonas fluorescens

Pseudomonas fluorescens is a psychrophilic bacterium that can cause dairy spoilage by producing heat-stable enzymes. Bacteriophages are proved as one of the alternatives to control spoilage bacteria in today's dairy industry. This study aimed to investigate how a previously identified phage YZU_PF006 prevents dairy spoilage caused by P. fluorescens. Results demonstrated that phage YZU_PF006 effectively controlled P. fluorescens growth and production of protease at 7°C and 28°C in milk in a phage concentration-dependent way. Phage YZU_PF006 at a multiplicity of infection (MOI) of 100 increased the pH values of milk by 1.43 at 28°C and 0.81 at 7°C, increased the particle size of milk by 2.74 μm at 28°C and 1.74 μm at 7°C. Phage YZU_PF006 reduced the free AA content by 15.36% at 28°C and 32.03% at 7°C, and decreased the contents of Glu (206.678 mmol/L at 28°C and 40.481 mmol/L at 7°C), Phe (94.137 mmol/L at 28°C and 144.137 mmol/L at 7°C) and other amino acids in milk. In contrast, high-throughput sequencing analysis revealed that phage YZU_PF006 specifically prevented the growth of Pseudomonas in raw milk at low temperatures. Results demonstrated that phage YZU_PF006 can be used alone or in combination with other control strategies to serve as one of the good antimicrobial candidates to control P. fluorescens contamination in dairy processing environments, and to promote the safety and sensory quality of raw milk and milk products.

FoxO transcription factors regulate urea cycle through Ass1

When amino acids are plentiful in the diet, the liver upregulates most enzymes responsible for amino acid degradation. In particular, the activity of urea cycle enzymes increases in response to high-protein diets to facilitate the excretion of excess nitrogen. KLF15 has been established as a critical regulator of amino acid catabolism including ureagenesis and we have recently identified FoxO transcription factors as an important upstream regulator of KLF15 in the liver. Therefore, we explored the role of FoxOs in amino acid metabolism under high-protein diet. Our findings revealed that the concentrations of two urea cycle-related amino acids, arginine and ornithine, were significantly altered by FoxOs knockdown. Additionally, using KLF15 knockout mice and an in vivo Ad-luc analytical system, we confirmed that FoxOs directly regulate hepatic Ass1 expression under high-protein intake independently from KLF15. Moreover, ChIP analysis showed that the high-protein diet increased FoxOs DNA binding without altering the nuclear protein amount. Therefore, FoxOs play a direct role in regulating ureagenesis via a KLF15-independent pathway in response to high-protein intake.

Serum Arginine Level for Predicting Early Allograft Dysfunction in Liver Transplantation Recipients by Targeted Metabolomics Analysis: A Prospective, Single-Center Cohort Study

Early allograft dysfunction (EAD) is a frequent phenomenon, leading to increased graft loss and higher mortality after liver transplantation (LT). Despite significant efforts for early diagnosis of EAD, there is no existing approach that can predict EAD on the first post-operative day. The aim is to define a metabolite-based biomarker on the first day after LT complicated with EAD. Ten patients diagnosed with EAD and 26 non-EAD are recruited for the study. A HPLC-MS/MS is used to determine 14 amino acids and 15 bile acids serum concentration. Comparative analyses are conducted between EAD and non-EAD groups. Arginine is identified as the most significant metabolite distinguishing the EAD and non-EAD groups, and therefore, is identified as a potential biomarker of EAD. The optimal cut-off value for arginine is 52.09 µmol L-1, with an AUROC of 0.804 (95% confidence interval: 0.638-0.917, p < 0.001), yielding a sensitivity of 100%, specificity of 53.8%, and Youden index of 0.54, NPVof 100%, and PPV of 45.45%. In summary, the study indicated that targeted metabolomics analysis would be a promising strategy for discovering novel biomarkers to predict EAD. The identified arginine may be helpful in developing an objective diagnostic method for EAD.

Leucine-Enriched Diet Reduces Fecal MPO but Does Not Protect Against DSS Colitis in a Mouse Model of Crohn's Disease-like Ileitis

Understanding the complex link between inflammation, gut health, and dietary amino acids is becoming increasingly important in the pathophysiology of inflammatory bowel disease (IBD). This study tested the hypothesis that a leucine-rich diet could attenuate inflammation and improve gut health in a mouse model of IBD. Specifically, we investigated the effects of a leucine-rich diet on dextran sulfate sodium (DSS)-induced colitis in germ-free (GF) SAMP1/YitFC (SAMP) mice colonized with human gut microbiota (hGF-SAMP). hGF-SAMP mice were fed one of four different diets: standard mouse diet (CHOW), American diet (AD), leucine-rich AD (AD + AA), or leucine-rich CHOW diet (CH + AA). Body weight, myeloperoxidase (MPO) activity, gut permeability, colonoscopy scores, and histological analysis were measured. Mice on a leucine-rich CHOW diet showed a decrease in fecal MPO prior to DSS treatment as compared to those on a regular diet (p > 0.05); however, after week five, prior to DSS, this effect had diminished. Following DSS treatment, there was no significant difference in gut permeability, fecal MPO activity, or body weight changes between the leucine-supplemented and control groups. These findings suggest that while a leucine-rich diet may transiently affect fecal MPO levels in hGF-SAMP mice, it does not confer protection against DSS-induced colitis symptoms or mitigate inflammation in the long term.

Comparison of nutritional value of the wild and cultivated spiny loaches at three growth stages

Environmental pollution and overfishing of wild spiny loach have led to the increased demand for breeding the fish. However, the nutritional value between the wild and cultivated spiny loaches was unknown. Therefore, this study aimed to evaluate the nutritional components among the wild and cultivated spiny loaches at different growth stages by analyzing and comparing the proximate compositions, fatty acids, amino acids and volatile compounds. Results showed that the cultivated ones had significantly higher energy and fat contents than the wild. Particularly, the cultivated second-age spiny loach contained the highest contents of polyunsaturated fatty acids (4.83 ± 0.01%) and EPA + DHA (0.85 ± 0.02%). Besides, the total essential amino acid content of cultivated second-age spiny loach was 2201.28, exceeding that recommended in the FAO/WTO scoring pattern (2,190). And it had the highest flavor amino acid (6.24 ± 0.04 g/100 g), essential amino acid index value (71.82) and higher contents of volatile compounds. Overall, the cultivated spiny loach, especially that at the second growth stage, displayed the highest nutritional value. The findings of this study would help farmers to harvest the suitable breeding stage of spiny loaches from the perspective of nutritional value, which is beneficial to the sustainable fish farming.

Coupled digital visualization and multi-omics uncover neurobehavioral dysfunction in zebrafish induced by resorcinol bis(diphenylphosphate)

Resorcinol bis(diphenylphosphate) (RDP) is an emerging pollutant that has been frequently detected in aquatic environments, although its toxicity is poorly characterized. To understand how RDP affects the neural system, two-month-old zebrafish were exposed to RDP at concentrations of 0.1 and 10 μg/L for 60 days. Following exposure, behavioral assessments were conducted, revealing the emergence of anxiety-like symptoms and memory deficits among the adult fish exposed to RDP, especially at the higher concentration. The increased blood-brain barrier (BBB) permeability (4.67-5.58-fold higher than the control group), reduced expression of tight junction proteins and the rapid brain RDP bioaccumulation (15.63 ± 2.34 ng/g wet weight) indicated the neurotoxicity of RDP. Excess reactive oxygen species synthesis (2.20-2.50-fold) was induced by RDP, leading to mitochondrial dysfunction and decreased production of neurotransmitters in the brain, specifically serotonin (5-HT; 16.3 %) and dopamine (DA; 18.1 %). Metabolomic analysis revealed that the low-toxicity RDP dose up-regulated lipid-related metabolites, while the high-toxicity dose up-regulated arachidonic acid metabolism and disrupted amino acid metabolism, including tryptophan and tyrosine metabolism related to dopaminergic and serotonergic pathways. The dysregulation of genes in various cellular processes was identified by transcriptomics, mainly involved in cell adhesion molecules and gap junctions, and oxidative phosphorylation, which were directly associated with BBB permeability and oxidative stress, respectively. Correlation analysis of microbiome-metabolite-host links built a mechanistic hypothesis for alterations in gut microbiota (Actinobacteriota and Proteobacteria) induced by high-dose RDP leading to the alteration of tryptophan, tyrosine, and arachidonic acid metabolism, decreasing the production of 5-HT and DA through the gut-brain axis. This study provides valuable insights into the mechanism underlying RDP-induced neurotoxicity in zebrafish, which can inform ecological risk assessments.

Amino Acid Composition of Thirty Food Fishes of the Ganga Riverine Environment for Addressing Amino Acid Requirement through Fish Supplementation

Amino acids are significant biomolecules that govern the major metabolic processes and act as precursors for macromolecules such as proteins that are crucial to life. Fish is an integral component of human nutrition and a dietary source of high-quality animal proteins and amino acids. In this context, the crude protein and amino acid compositions of food fish from different landing stations of the Ganga river have been determined. The Kjeldahl method was utilized to determine the crude protein content and the amino acids were analyzed using high-performance liquid chromatography (HPLC); data on 30 food fish were assessed. The study showed that among the fish studied, Eleotris fusca, Macrobrachium malcomsonii, and Mystus cavasius were rich in most of the amino acids important for human nutrition, such as glycine, glutamic acid, cysteine, threonine, phenylalanine, methionine, lysine, leucine, isoleucine, histidine, and valine. Further, it was observed that the daily consumption of these fish (approximately 50 g) can fulfil the daily requirement of these individual amino acids for an adult human with a body weight of 60 kg. Therefore, the amino acid composition analyzed in the present study could be utilized for recommendation by clinicians according to the requirement for specific amino acids, and fish can be prescribed as a natural supplement against the amino acid requirement.

Synthesis and Biological Evaluation of Fluorine-18 and Deuterium Labeled l-Fluoroalanines as Positron Emission Tomography Imaging Agents for Cancer Detection

To fully explore the potential of 18F-labeled l-fluoroalanine for imaging cancer and other chronic diseases, a simple and mild radiosynthesis method has been established to produce optically pure l-3-[18F]fluoroalanine (l-[18F]FAla), using a serine-derivatized, five-membered-ring sulfamidate as the radiofluorination precursor. A deuterated analogue, l-3-[18F]fluoroalanine-d3 (l-[18F]FAla-d3), was also prepared to improve metabolic stability. Both l-[18F]FAla and l-[18F]FAla-d3 were rapidly taken up by 9L/lacZ, MIA PaCa-2, and U87MG cells and were shown to be substrates for the alanine-serine-cysteine (ASC) amino acid transporter. The ability of l-[18F]FAla, l-[18F]FAla-d3, and the d-enantiomer, d-[18F]FAla-d3, to image tumors was evaluated in U87MG tumor-bearing mice. Despite the significant bone uptake was observed for both l-[18F]FAla and l-[18F]FAla-d3, the latter had enhanced tumor uptake compared to l-[18F]FAla, and d-[18F]FAla-d3 was not specifically taken up by the tumors. The enhanced tumor uptake of l-[18F]FAla-d3 compared with its nondeuterated counterpart, l-[18F]FAla, warranted the further biological investigation of this radiotracer as a potential cancer imaging agent.

Effects of radiation mitigating amino acid mixture on mice of different sexes

To date, few FDA-approved medical countermeasures are available for addressing hematopoietic acute radiation syndrome (H-ARS). In this study, we present our latest research findings focusing on the evaluation of a novel radiation mitigator known as the mitigating amino acid mixture (MAAM). MAAM is composed of five amino acids as the recently reported amino acid-based oral rehydration solution for mitigating gastrointestinal (GI)-ARS. CD2F1 male and female mice were exposed to 60Co-γ total body irradiation (TBI) at 9.0 or 9.5 Gy. Following irradiation, mice were orally administered with MAAM or a saline vehicle control once daily for a duration of 14 days, commencing 24 h after TBI. Mouse survival and body weight change were monitored for 30 days after irradiation. Complete blood counts (CBCs), bone marrow (BM) stem and progenitor cell survival (clonogenicity), and a serum cytokine antibody array were analyzed using samples from day 30 surviving mice. Our data revealed that MAAM treatment significantly enhanced survival rates in irradiated male CD2F1 mice, and the survival rate increased from 25% in the vehicle control group to 60% in the MAAM-treated group (p < 0.05) after 9.0 Gy TBI. The number of BM colonies significantly increased from 41.8 ± 6.4 /104 cells (in the vehicle group) to 78.5 ± 17.0 /104 cells (in the MAAM group) following 9.0 Gy TBI. Furthermore, MAAM treatment led to a decrease in the levels of six cytokines/proteins [cluster of differentiation 40 (CD40), interleukin (IL)-17A, C-X-C motif chemokine 10 (CXCL10/CRG-2), cutaneous T cell-attracting chemokine (CTACK), macrophage inflammatory protein (MIP)-3β, and IL-1β] and an increase in the levels of five other cytokines/proteins [IL-3Rβ, IL-5, leptin, IL-6, and stem cell factor (SCF)] in mouse serum compared to the vehicle group after 9.0 Gy TBI. However, similar alleviating effects of MAAM were not observed in the irradiated CD2F1 female mice. The serum cytokine profile in the irradiated female mice was different compared to the irradiated male mice. In summary, our data suggest that the beneficial effects of the mitigative amino acid combination treatment after radiation exposure may depend on sex.

The role of different nutrients in the prevention and treatment of cardiovascular diseases

Cardiovascular health is a hot topic around the world, and as the incidence of cardiovascular disease increases each year, people are increasingly focusing on the management of their heart health. Dietary and lifestyle changes as non-pharmacological treatments have been increasingly recognized as important in the prevention of cardiovascular disease and in reducing the risk of cardiovascular accidents. Awareness of different nutrients and their effects on cardiovascular health is important for establishing a good dietary pattern. This review summarizes the effects of the five major nutrients in the daily diet, namely carbohydrates, proteins, dietary fats, vitamins, and minerals, on cardiovascular health, and aims to provide a more comprehensive understanding of the effects of a healthy dietary pattern on cardiovascular health.

Patterns of the Nutrients and Metabolites in Apostichopus japonicus Fermented by Bacillus natto and Their Ability to Alleviate Acute Alcohol Intoxication

The aim of this study was to understand the changes in nutrient composition and differences in metabolites in Apostichopus japonicus fermented by Bacillus natto and their function in alleviating acute alcohol intoxication (AAI) through in vivo studies. The results showed no significant difference between the basic components of sea cucumber (SC) and fermented sea cucumber (FSC). The SC proteins were degraded after fermentation, and the amino acid content in FSC was significantly increased. The differentially abundant metabolites of SC and FSC were identified by LC-MS/MS. The contents of amino acid metabolites increased after fermentation, and arachidonic acid metabolism was promoted. The results demonstrated that FSC alleviated AAI by improving the activities of alcohol-metabolizing enzymes and antioxidant enzymes in the liver but did not alleviate the accumulation of triglycerides. Our results will provide beneficial information for the development and application of new products from FSC.

Density Functional Theory Study of Cu6 Nanoclusters as a Phenylalanine Detector

Research on amino acids is an attractive area because of their application in metabolism, cancer treatment, growth, and repair of body tissue, and RNA and DNA syntheses. Twenty amino acids are primarily responsible for protein synthesis. In our study, we used a Cu6 nanocluster as an amino acid detector. For the investigation, we adsorbed amino acids on the Cu6 nanocluster and studied their UV-visible spectra. It is observed that all of the Cu6-amino acid complexes have peaks at near 380 nm wavelength except the Cu-phenylalanine complex, where two UV-visible peaks are found at wavelengths 351 nm (excitation energy 3.49 eV) and 403 nm (excitation energy 3.02 eV), respectively, which originated from the HOMO - 2 to LUMO (28%) and HOMO - 1 to LUMO (38%) transitions. Due to this unique transition, the Cu6 nanocluster can be used for the detection of the phenylalanine amino acid out of the 20 amino acids.

A new insight into mechanism of colchicine poisoning based on untargeted metabolomics

BACKGROUND

Colchicine (COL) is a well-known plant-derived mitogenic toxin that has been widely applied for the treatment of immune system diseases and various cancers. However, its clinical use is severely limited by frequent occurrence of poisoning accidents, and the mechanism of COL poisoning is not clear yet.

PURPOSE

The present study aimed to unveil how COL works as a toxin based on untargeted metabolomics analysis of animal models and clinical human case.

METHODS

KM mice orally administered COL were used to establish poisoning models, and plasma samples were collected for untargeted metabolomics analysis. The data mining was performed to screen dose-dependent differences and disturbed metabolic pathways. The blood samples collected from clinical COL poisoning human case at various time points during treatment period were further analyzed to investigate the temporal changes in the metabolic disposition of COL in vivo and also verify the findings from mice. Finally, the expression of key pathways was evaluated by ELISA and Western blotting analysis.

RESULTS

Histological examination demonstrated systemic toxicity of COL poisoning in mice. Metabolite profiling analysis of plasma samples from model mice and clinical case both revealed that COL poisoning could significantly disturb in vivo metabolism of amino acid and lipid metabolism by the FXR/AMPK signal pathway. Quantitative monitoring of the metabolic process of COL further demonstrated that it could be greatly ameliorated with the rapid metabolic transformation of COL in vivo, which thus may be an effective detoxification pathway for COL poisoning.

CONCLUSION

The findings of the present study provided new insight into the molecular mechanism of COL poisoning, thus helpful for guiding reasonable application of this phytotoxin.

Novel chair graphene nanotubes as adsorbing medium for alanine and asparagine amino acids - A DFT outlook

Amino acids are required to make protein. The deficiency of amino acids leads to a lack of sleep and mood. Among various amino acids, we conducted the adsorption studies of alanine and asparagine amino acids on a novel one-dimensional material, chair graphene nanotube. The stability of the chair graphene nanotube is ensured with the negative formation energy, which is -6.490 eV/atom. The energy band gap of bare chair graphene nanotube is 1.022 eV, which possesses a semiconductor nature. The stable chair graphene nanotube is used as adsorbing material for alanine and asparagine amino acids. Besides, alanine and asparagine are physisorbed on chair graphene nanotubes that are confirmed by the range of adsorption energy from -0.107 eV to -0.718 eV. Upon adsorption of amino acids, the charge transfer outcome shows that chair graphene nanotubes behave as donors of electrons to alanine and asparagine. Further, the changes in the band gap of the chair graphene nanotube are noticed from the results of band structure and PDOS spectrum. The changes in the electron density also reveal the changes in the electronic properties of the chair graphene nanotube owing to alanine and asparagine sorption. The proposed report portrays the adsorption attributes of alanine and asparagine amino acids on 1D chair graphene nanotubes.

Predictive Ability of Serum Amino Acid Levels to Differentiate Fibromyalgia Patients from Healthy Subjects

BACKGROUND

Fibromyalgia is a complex illness to diagnose and treat.

OBJECTIVES

To evaluate a broad range of circulating free amino acid (AA) levels in fibromyalgia patients as well as the ability of the AAs to differentiate fibromyalgia patients from healthy subjects.

DESIGN

We carried out a case-control study to evaluate AA levels in 62 patients with fibromyalgia and 78 healthy subjects. This study adheres to the STROBE guidelines.

METHODS

AAs content was assayed by HPLC in serum samples. The predictive value of AA levels in fibromyalgia was determined by receiver operating characteristic (ROC) curve and forward binary logistic regression analyses.

RESULTS

Fibromyalgia patients showed higher serum levels of aspartic acid, glutamic acid, aminoadipic acid, asparagine, histidine, 3-methyl-histidine, 5-methyl-histidine, glycine, threonine, taurine, tyrosine, valine, methionine, isoleucine, phenylalanine, leucine, ornithine, lysine, branched chain AAs (BCAAs), large neutral AAs, essential AAs (EAAs), non-essential AAs (NEAAs), basic AAs, EAAs/NEAAs ratio, phenylalanine/tyrosine ratio, and global arginine bioavailability ratio than the controls. Serum alanine levels were lower in patients than in controls. According to ROC analysis, most of these AAs may be good markers for differentiating individuals with fibromyalgia from healthy subjects. Results of logistic regression showed that the combination of glutamic acid, histidine, and alanine had the greatest predictive ability to diagnose fibromyalgia.

CONCLUSIONS

Our results show an imbalance in serum levels of most AAs in patients with fibromyalgia, which suggest a metabolic disturbance. The determination of serum levels of these AAs may aid in the diagnosis of fibromyalgia, in combination with clinical data of the patient.

A ratiometric fluorescent paper sensor based on dye-embedded MOF for high-sensitive detection of arginine

Ratiometric fluorescent sensors can suppress the interference of factors unrelated to analysis due to their built-in self-calibration characteristics, which exhibit higher sensitivity and more obvious visual detection in the process of qualitative and quantitative analysis. Herein, we constructed a ratiometric fluorescence probe based on fluorescent/colorimetric dual-mode method for the determination of arginine by encapsulating rhodamine B in-situ into UiO-66-NH2 MOFs (UiO-66-NH2@RhB). The as-prepared probe showed dual-emission characteristics under a single excitation wavelength. The fluorescence intensity of UiO-66-NH2 was increased significantly by arginine, while the emission peak intensity of rhodamine B remained stable, resulting in a single-signal response with fixed reference. Furthermore, the practicality of the presented sensor was successfully validated by quantitative detection of arginine in human serum. More significantly, paper-based sensors for arginine detection were devised by using carboxymethyl cellulose modified filter papers. Under the irradiation of ultraviolet light, the paper-based sensors would produce obvious color variation from lightpink to bluish violet. This work provided a convenient and efficient method for on-site detection of arginine.

Chemical Profile of Turnip According to the Plant Part and the Cultivar: A Multivariate Approach

Turnip (Brassica rapa subsp. rapa) is a cruciferous plant cultivated worldwide that serves as a source of nutrients and bioactive compounds. Most turnip studies have focused on a few compounds or on part of the plant. The establishment of a complete chemical profile of different plant parts would facilitate its use for nutritional and medicinal purposes. In the current study, mineral elements, soluble sugars, free amino acids (FAA), total phenols (TP), total flavonoids (TF), and glucosinolates (GS) were quantified in the leaves, stems, and roots. Results were compared for 20 strains of turnip. The outcomes showed significant differences between parts of the plant and strains. The leaves exhibited the highest TF, TP, indispensable FAA, and microelement levels, and they showed a higher GS. Moreover, the stems had a high content of GS and macroelements. Furthermore, the roots showed high levels of free sugars and total FAA. The findings of this work provide the basis for utilizing each part of the turnip plant based on its chemical composition.

Perspective: Developing a Nutrient-Based Framework for Protein Quality

The future of precision nutrition requires treating amino acids as essential nutrients. Currently, recognition of essential amino acid requirements is embedded within a generalized measure of protein quality known as the PDCAAS (Protein Digestibility-Corrected Amino Acid Score). Calculating the PDCAAS includes the FAO/WHO/UNU amino acid score, which is based on the limiting amino acid in a food, that is, the single amino acid with the lowest concentration compared to the reference standard. That "limiting" amino acid score is then multiplied by a bioavailability factor to obtain the PDCAAS, which ranks proteins from 0.0 (poor quality) to 1.0 (high quality). However, the PDCAAS has multiple limitations: it only allows for direct protein quality comparison between 2 proteins, and it is not scalable, transparent, or additive. We therefore propose that shifting the protein quality evaluation paradigm from the current generalized perspective to a precision nutrition focus treating amino acids as unique, metabolically active nutrients will be valuable for multiple areas of science and public health. We report the development and validation of the Essential Amino Acid 9 (EAA-9) score, an innovative, nutrient-based protein quality scoring framework. EAA-9 scores can be used to ensure that dietary recommendations for each essential amino acid are met. The EAA-9 scoring framework also offers the advantages of being additive and, perhaps most importantly, allows for personalization of essential amino acid needs based on age or metabolic conditions. Comparisons of the EAA-9 score with PDCAAS demonstrated the validity of the EAA-9 framework, and practical applications demonstrated that the EAA-9 framework is a powerful tool for precision nutrition applications.

Personalized Nutritional Strategies to Reduce Knee Osteoarthritis Severity and Ameliorate Sarcopenic Obesity Indices: A Practical Guide in an Orthopedic Setting

Knee osteoarthritis (KOA) is one of the most common joint diseases, especially in individuals with obesity. Another condition within this population, and which presents frequently, is sarcopenic obesity (SO), defined as an increase in body fat and a decrease in muscle mass and strength. The current paper aims to describe recent nutritional strategies which can generally improve KOA clinical severity and, at the same time, ameliorate SO indices. Searches were carried out in the PubMed and Science Direct databases and data were summarized using a narrative approach. Certain key findings have been revealed. Firstly, the screening and identification of SO in patients with KOA is important, and to this end, simple physical performance tests and anthropometric measures are available in the literature. Secondly, adherence to a Mediterranean diet and the achievement of significant body weight loss by means of low-calorie diets (LCDs) remain the cornerstone nutritional treatment in this population. Thirdly, supplementation with certain micronutrients such as vitamin D, essential and non-essential amino acids, as well as whey protein, also appear to be beneficial. In conclusion, in the current review, we presented a detailed flowchart of three different nutritional tracks that can be adopted to improve both KOA and SO based on joint disease clinical severity.

Chemical composition and anti-cholesterol activity of tea (Camellia sinensis) flowers from albino cultivars

Albino tea cultivars are mutant tea plants with altered metabolisms. Current studies focus on the leaves while little is known about the flowers. To evaluate tea flowers from different albino cultivars, the chemical composition and anti-cholesterol activity of tea flowers from three albino cultivars (i.e., Baiye No.1, Huangjinya, and Yujinxiang) were compared. According to the results, tea flowers from Yujinxiang had more amino acids but less polyphenols than tea flowers from the other two albino cultivars. A reduced content of procyanidins and a high chakasaponins/floratheasaponins ratio were characteristics of tea flowers from Yujinxiang. In vitro anti-cholesterol activity assays revealed that tea flowers from Yujinxiang exhibited stronger activity in decreasing the micellar cholesterol solubility, but not in cholesterol esterase inhibition and bile salt binding. It was noteworthy that there were no specific differences on the chemical composition and anti-cholesterol activity between tea flowers from albino cultivars and from Jiukeng (a non-albino cultivar). These results increase our knowledges on tea flowers from different albino cultivars and help food manufacturers in the cultivar selection of tea flowers for use.

In silico engineering a CD80 variant with increased affinity to CTLA-4 and decreased affinity to CD28 for optimized cancer immunotherapy

CD80 or cluster of differentiation 80, also known as B7-1, is a member of the immunoglobulin super family, which binds to CTLA-4 and CD28 T cell receptors and induces inhibitory and inductive signals respectively. Although CTLA-4 and CD28 receptors belong to the same protein family, slight differences in their structures leads to CD80 having a higher binding affinity to CTLA-4 (-14.55 kcal/mol) compared with CD28(-12.51 kcal/mol). In this study, we constructed a variant of CD80 protein with increased binding affinity to CTLA-4 and decreased binding affinity to CD28. This variant has no signaling capability, and can act as a cap for these receptors to protect them from natural CD80 proteins existing in the body. The first step was the evolutionary and alanine scanning analysis of CD80 protein to determine conserved regions in this protein. Next, complex alanine scanning technique was employed to determine CD80 protein hotspots in CD80-CTLA-4 and CD80-CD28 protein complexes. This information was fed into a computational model developed in R for in silico mutagenesis and CD80 variant library construction. The 3D structures of variants were modeled using the Swiss model webserver. After modeling the 3D structures, HADDOCK server was employed to build all protein-protein complexes, which contain CTLA-4-CD80 variant complexes, Wild type CD80-CD28 complexes and CD28-CD80 variant complexes. Protein-protein binding free energy was determined using FoldX and the variant number 316 with mutations at 29, 31, 33 positions showed increased binding affinity to CTLA-4 (-21.43 kcal/mol) and decreased binding affinity to CD28 (- 9.54 kcal/mol). Finally, molecular dynamics (MD) simulations confirmed the stability of variant 316. In conclusion, we designed a new CD80 protein variant with potential immunotherapeutic applications.

Protein Content and Amino Acid Profiles of Selected Edible Insect Species from the Democratic Republic of Congo Relevant for Transboundary Trade across Africa

This study analyzed the protein content of ten edible insect species (using the Dumas method), then focused on the amino acid (AA) profiles of the six major commercially relevant species using HPLC (high-pressure (or performance) liquid chromatography). The protein contents varied significantly from 46.1% to 52.9% (dry matter); the Orthoptera representative yielding both the highest protein content and the highest values in three essential amino acids (EAAs). Regarding Lepidoptera species, the protein content of Saturniidae varied more than for Notodontidae. Imbrasia ertli gave the best example of a species that could be suggested for dietary supplementation of cereal-based diets, as the sample contained the highest values in five EAAs and for the EAA index. Furthermore, first-limiting AAs in the selected insects have also been pointed out (based on a species-specific AA score), supporting that the real benefit from eating insects is correlated to a varied diet. Additionally, preliminary insights into AA distribution patterns according to taxa provided three clusters based on protein quality and should be completed further to help tailor prescriptions of dietary diets. Since the AA composition of the selected insects was close to the FAO/WHO EAA requirement pattern for preschool children and met the requirements of 40% EAAs with high ratio EAAs/NEAAs, the current study endorses reports of edible insects as nutrient-rich and sustainable protein sources.

Potential of Natural Honey in Controlling Obesity and its Related Complications

Honey has a long history of therapeutic properties for multiple diseases, including inflammation and oxidative stress. This review aimed to provide a better understanding and renewed interest in the potential role of honey in obesity control, obesity-related diseases treatment and weight management, with specific reference to its components and the effect of honey overall. There is compelling evidence that honey possesses the desired properties for this purpose, as seen in the in vitro, in silico, in vivo and clinical analyses discussed in this review. This review also highlights the components potentially responsible for the health benefits of honey. Honey and its components reduce blood sugar levels, improve insulin sensitivity and lipid metabolism by reducing triglycerides, and reduce total cholesterol and LDL levels while increasing HDL levels that prevent excessive weight gain and reduce the risk of obesity and its complications. Further controlled studies are necessary to validate the role of honey in the management of obesity, both as a preventive and as a therapeutic agent.

Deciphering the Heterogeneity of the Internal Environment of Hippocampal Neurons during Maturation by Raman Spectroscopy

Hippocampal neurons are sensitive to changes in the internal environment and play a significant role in controlling learning, memory, and emotions. A remarkable characteristic of the aging brain is its ability to shift from a state of normal inflammation to excessive inflammation. Various cognitive abilities of the elderly may suffer from serious harm due to the change in the neural environment. Hippocampal neurons may have various subsets involved in controlling their internal environment at different stages of development. Developmental differences may eventually result from complex changes in the dynamic neuronal system brought on by metabolic changes. In this study, we used an in vitro hippocampal neuron model cultured in C57BL/6J mice in conjugation with Raman spectroscopy to examine the relative alterations in potential biomarkers, such as levels of metabolites in the internal environment of hippocampal neurons at various developmental stages. The various differentially expressed genes (DEGs) of hippocampal neurons at various developmental stages were simultaneously screened using bioinformatics, and the biological functions as well as the various regulatory pathways of DEGs were preliminarily analyzed, providing an essential reference for investigating novel therapeutic approaches for diseases that cause cognitive impairment, such as Alzheimer's disease. A stable hippocampal neuron model was established using the GIBCO C57BL/6J hippocampal neuron cell line as a donor and in vitro hippocampal neuron culture technology. The Raman peak intensities of culture supernatants from the experimental groups incubated for 0, 7, and 14 days in vitro(DIV) were examined. The GEO database was used to screen for different DEGs associated with various developmental stages. The data was then analyzed using a statistical method called orthogonal partial least squares discriminant analysis (OPLS-DA). The levels of ketogenic and glycogenic amino acids (such as tryptophan, phenylalanine, and tyrosine), lipid intake rate, glucose utilization rate, and nucleic acid expression in the internal environment of hippocampal neurons were significantly different in the 14 DIV group compared to the 0 DIV and 7 DIV groups (P < 0.01). The top 10 DEGs with neuronal maturation were screened, and the results were compared to the OPLS-DA model's analysis of the differential peaks. It was found that different genes involved in maturation can directly relate to changes in the body's levels of ketogenic and glycogenic amino acids (P < 0.01). The altered expression of the maturation-related genes epidermal growth factor receptor, protein tyrosine kinase 2-beta, discs large MAGUK scaffold protein 2, and Ras protein-specific guanine nucleotide releasing factor 1 may be connected to the altered uptake of ketogenic and glycogenic amino acids and nucleic acids in the internal environment of neurons at different developmental stages. The levels of ketogenic, glycogenic amino acids, and lipid intake increased while glucose utilization decreased, which may be related to mature neurons' metabolism and energy use. The decline in nucleic acid consumption could be connected to synaptic failure. The Raman spectroscopy fingerprint results of relevant biomarkers in conjugation with multivariable analysis and biological action targets suggested by differential genes interpret the heterogeneity of the internal environment of mature hippocampal neurons in the process of maturation, open a new idea for exploring the dynamic mechanism of the exchange energy metabolism of information molecules in the internal environment of hippocampal neurons, and provide a new method for studying this process.

Ablation of Tas1r1 Reduces Lipid Accumulation Through Reducing the de Novo Lipid Synthesis and Improving Lipid Catabolism in Mice

Amino acid sensing plays an important role in regulating lipid metabolism by sensing amino acid nutrient disturbance. T1R1 (umami taste receptor, type 1, member 1) is a membrane G protein-coupled receptor that senses amino acids. Tas1r1-knockout (KO) mice were used to explore the function of umami receptors in lipid metabolism. Compared with wild-type (WT) mice, Tas1r1-KO mice showed decreased fat mass (P < 0.05) and adipocyte size, lower liver triglyceride (7.835 ± 0.809 vs 12.463 ± 0.916 mg/g WT, P = 0.013) and total cholesterol levels (0.542 ± 0.109 vs 1.472 ± 0.044 mmol/g WT, P < 0.001), and reduced lipogenesis gene expressions in adipose and liver tissues. Targeted liver amino acid metabolomics showed that the amino acid content of Tas1r1-KO mice was significantly decreased, which was consistent with the branched-chain ketoacid dehydrogenase protein levels. Proteomics analysis showed that the upregulated proteins were enriched in lipid and steroid metabolism pathways, and parallel reaction monitoring results illustrated that Tas1r1 ablation promoted lipid catabolism through oxysterol 7 α-hydroxylase and insulin-like growth factor binding protein 2. In summary, Tas1r1 disruption in mice could reduce lipid accumulation by reducing de novo lipid synthesis and improving lipid catabolism.

Pesticides Exposure-Induced Changes in Brain Metabolome: Implications in the Pathogenesis of Neurodegenerative Disorders

Pesticides have been used in agriculture, public health programs, and pharmaceuticals for many decades. Though pesticides primarily target pests by affecting their nervous system and causing other lethal effects, these chemical entities also exert toxic effects in inadvertently exposed humans through inhalation or ingestion. Mounting pieces of evidence from cellular, animal, and clinical studies indicate that pesticide-exposed models display metabolite alterations of pathways involved in neurodegenerative diseases. Hence, identifying common key metabolites/metabolic pathways between pesticide-induced metabolic reprogramming and neurodegenerative diseases is necessary to understand the etiology of pesticides in the rise of neurodegenerative disorders. The present review provides an overview of specific metabolic pathways, including tryptophan metabolism, glutathione metabolism, dopamine metabolism, energy metabolism, mitochondrial dysfunction, fatty acids, and lipid metabolism that are specifically altered in response to pesticides. Furthermore, we discuss how these metabolite alterations are linked to the pathogenesis of neurodegenerative diseases and to identify novel biomarkers for targeted therapeutic approaches.

Endothelial Cell Metabolism in Vascular Functions

Simple Summary

Recent findings in the field of vascular biology are nourishing the idea that targeting the endothelial cell metabolism may be an alternative strategy to antiangiogenic therapy, as well as a novel therapeutic approach for cardiovascular disease. Deepening the molecular mechanisms regulating how ECs re-adapt their metabolic status in response to the changeable conditions of the tissue microenvironment may be beneficial to develop novel innovative treatments to counteract the aberrant growth of vasculature.

Abstract

The endothelium is the innermost layer of all blood and lymphatic vessels composed of a monolayer of specialized endothelial cells (ECs). It is regarded as a dynamic and multifunctional endocrine organ that takes part in essential processes, such as the control of blood fluidity, the modulation of vascular tone, the regulation of immune response and leukocyte trafficking into perivascular tissues, and angiogenesis. The inability of ECs to perform their normal biological functions, known as endothelial dysfunction, is multi-factorial; for instance, it implicates the failure of ECs to support the normal antithrombotic and anti-inflammatory status, resulting in the onset of unfavorable cardiovascular conditions such as atherosclerosis, coronary artery disease, hypertension, heart problems, and other vascular pathologies. Notably, it is emerging that the ability of ECs to adapt their metabolic status to persistent changes of the tissue microenvironment could be vital for the maintenance of vascular functions and to prevent adverse vascular events. The main purpose of the present article is to shed light on the unique metabolic plasticity of ECs as a prospective therapeutic target; this may lead to the development of novel strategies for cardiovascular diseases and cancer.

Sex-dependent effects on the gut microbiota and host metabolome in type 1 diabetic mice

Sexual dimorphism exists in the onset and development of type 1 diabetes (T1D), but its potential pathological mechanism is poorly understood. In the present study, we examined sex-specific changes in the gut microbiome and host metabolome of T1D mice via 16S rRNA gene sequencing and nuclear magnetic resonance (NMR)-based metabolomics approach, and aimed to investigate potential mechanism of the gut microbiota-host metabolic interaction in the sexual dimorphism of T1D. Our results demonstrate that female mice had a greater shift in the gut microbiota than male mice during the development of T1D; however, host metabolome was more susceptible to T1D in male mice. The correlation network analysis indicates that T1D-induced host metabolic changes may be regulated by the gut microbiota in a sex-specific manner, mainly involving short-chain fatty acids (SCFAs) metabolism, energy metabolism, amino acid metabolism, and choline metabolism. Therefore, our study suggests that sex-dependent "gut microbiota-host metabolism axis" may be implicated in the sexual dimorphism of T1D, and the link between microbes and metabolites might contribute to the prevention and treatment of T1D.

Metabolite G-Protein Coupled Receptors in Cardio-Metabolic Diseases

G protein-coupled receptors (GPCRs) have originally been described as a family of receptors activated by hormones, neurotransmitters, and other mediators. However, in recent years GPCRs have shown to bind endogenous metabolites, which serve functions other than as signaling mediators. These receptors respond to fatty acids, mono- and disaccharides, amino acids, or various intermediates and products of metabolism, including ketone bodies, lactate, succinate, or bile acids. Given that many of these metabolic processes are dysregulated under pathological conditions, including diabetes, dyslipidemia, and obesity, receptors of endogenous metabolites have also been recognized as potential drug targets to prevent and/or treat metabolic and cardiovascular diseases. This review describes G protein-coupled receptors activated by endogenous metabolites and summarizes their physiological, pathophysiological, and potential pharmacological roles.

The Molecular Effects of Dietary Acid Load on Metabolic Disease (The Cellular PasaDoble: The Fast-Paced Dance of pH Regulation)

Metabolic diseases are becoming more common and more severe in populations adhering to western lifestyle. Since metabolic conditions are highly diet and lifestyle dependent, it is suggested that certain diets are the cause for a wide range of metabolic dysfunctions. Oxidative stress, excess calcium excretion, inflammation, and metabolic acidosis are common features in the origins of most metabolic disease. These primary manifestations of "metabolic syndrome" can lead to insulin resistance, diabetes, obesity, and hypertension. Further complications of the conditions involve kidney disease, cardiovascular disease, osteoporosis, and cancers. Dietary analysis shows that a modern "Western-style" diet may facilitate a disruption in pH homeostasis and drive disease progression through high consumption of exogenous acids. Because so many physiological and cellular functions rely on acid-base reactions and pH equilibrium, prolonged exposure of the body to more acids than can effectively be buffered, by chronic adherence to poor diet, may result in metabolic stress followed by disease. This review addresses relevant molecular pathways in mammalian cells discovered to be sensitive to acid - base equilibria, their cellular effects, and how they can cascade into an organism-level manifestation of Metabolic Syndromes. We will also discuss potential ways to help mitigate this digestive disruption of pH and metabolic homeostasis through dietary change.

The effect of an energy additive on the metabolism of cattle

The objective of this study was to determine the effect of an energy additive on the metabolism of cattle. This article provides information on the analysis of the diet of young cattle calculated for when the animals were both indoors and outdoors. The ration was prepared for 40 heifers, divided into 4 groups consisting of 10 animals in each group. Three of these groups were fed different amounts of a high-energy additive, which was not fed to the control group. The effectiveness of the additive was analyzed according to the balance experiment and by calculating digestibility coefficients. It was determined that the percentage of nitrogen use in young animals was higher in the groups that were fed the additive than in the control group. Increasing the dose of the additive increased the level of nitrogen use. Comparative analysis of live weight indicated intergroup differences in favor of heifers in the groups that were fed the additive of 1.34% to 2.41% at the age of 9 mo; 2.51% to 4.16% at 12 mo; 3.14% to 5.46% at 15 mo; and 3.57% to 6.30% at 18 mo. The average daily growth dynamics indicated a gradual increase in all animals up to 15 mo, with a slight decrease by 18 mo of age. The difference among the groups ranged from 5.08% to 8.85% at 6 to 9 mo of age; 7.08% to 10.79% at 9 to 12 mo; 5.64% to 10.97% at 12 to 15 mo; and 6.05% to 11.11% at 18 mo. It was concluded that feeding the energy additive Tanrem to heifers increased their metabolism so that nitrogen use was improved, and feed was digested more efficiently, which in turn improved the growth of animals. Using an energy additive at the mid-range dose of 500 g a day per animal is recommended, since the effect was similar at the mid-range and maximum dosages.

Nutritional metabolites in Brassica rapa subsp. chinensis var. parachinensis (choy sum) at three different growth stages: Microgreen, seedling and adult plant

Choy sum is a commonly consumed Asian green leafy brassica vegetable. A comprehensive spectrum of nutritional important metabolites, including amino acids, plant sugars, essential minerals, vitamins (A, B9, E, and K1) and glucosinolates were systematically quantified using LC-QQQ-MS, GC-QQQ-MS and ICP-MS. Significant metabolic profile shifts were observed during the three major developmental stages (microgreen, seedling and adult) studied. Primary metabolites, especially essential amino acids decreased while most plant sugars increased from microgreens to seedlings. Carotenoids, such as violaxanthin, neoxanthin, together with vitamin K1 were higher in the seedlings whereas CHO-folate vitamers and β-cryptoxanthin were much lower in adult plants. Most essential minerals were concentrated in the microgreens, while sodium increased in adult plants. Aliphatic glucosinolates in microgreens were converted to indolic glucosinolates in the seedlings and further to aromatic glucosinolates in the adults. Overall findings reveal that most of the nutritional metabolites were concentrated either in the microgreens or seedlings.