Amino Acid Research Articles

Ratio of non-protein calories to grams of amino acids and amino acid blood levels in preterm infants receiving parenteral nutrition

Background Studies evaluating the optimal intake of amino acids for preterm infants have often not considered the effect of the non-protein calorie to grams of amino acids ratio (NPKcal:g AA) in parenteral nutrition solutions. The objectives of this study were to document the ratio in a group of preterm infants and explore any associations of the ratio to AA and acylcarnitine levels. Methods This was descriptive cohort study of data collected from a previously published prospective study evaluating the influence that gestational age had on amino acid and acylcarnitine profiles in preterm infants ≤31 weeks postmenstrual age. Acylcarnitine and AA levels on day of life 7 of three study groups, based upon terciles of the NPKcal:g AA, who were receiving minimal enteral feedings and an enterally fed comparison group were measured. Growth velocities and changes in z-scores were also evaluated. Results NPKcal:g AA terciles were: 6.3–17.6:1 (low, N = 153), 17.7–21.2:1 (mid, N = 150), and 21.3–36.2:1 (high, N = 159). Higher levels of ornithine, citrulline, blood urea nitrogen, isovalerylcarnitine + methylbutyrylcarnitine, and octenoylcarnitine were found in the low versus the high group. From day 1–42 of life, the low group had a lower head circumference (HC) growth velocity and the low and mid groups had more negative HC changes in z-scores versus the enteral group. Conclusions This study suggests that preterm infants may receive parenteral nutrition solutions containing inadequate energy to prevent oxidation of administered AA. The impact of inadequate non-protein caloric intake needs to be considered when evaluating growth and outcomes in nutritional studies of VLBW infants.

Campylobacter molothri sp. nov. isolated from wild birds

Twenty-nine hippuricase-positive Campylobacter strains were isolated from wild birds and river water. Previous characterization using atpA typing indicated that these strains were related to Campylobacter jejuni and Campylobacter coli but were most similar to three recently described hippuricase-positive Campylobacter species recovered from zebra finches, i.e. C. aviculae, C. estrildidarum and C. taeniopygiae. Phylogenetic analyses using 330 core genes placed the 29 strains into a clade well separated from the other Campylobacter taxa, indicating that these strains represent a novel Campylobacter species. Pairwise digital DNA–DNA hybridization and average nucleotide identity values were below 70 and 95 %, respectively, thus providing further supporting evidence of a novel taxon. Standard phenotypic testing was performed. All strains are microaerobic or anaerobic, motile, Gram-negative, spiral cells that are oxidase, catalase and nitrate reductase positive, but urease negative. Genomic analyses indicate that the 29 strains can potentially synthesize very few amino acids de novo and are auxotrophic for many amino acids and cofactors, similar to the species composing the Campylobacter lari group. In addition, these strains encode complete Entner–Doudoroff and Leloir pathways, suggesting that they may possess the ability to utilize both glucose and galactose; these pathways were also identified in the genomes of the zebra finch-associated taxa. The data presented here show that these strains represent a novel species within Campylobacter, for which the name Campylobacter molothri sp. nov. (type strain RM10537T=LMG 32306T=CCUG 75331T) is proposed.

СПОСОБ ПОЛУЧЕНИЯ БЕЗГЛЮТЕНОВОЙ ЛЬНЯНОЙ МУКИ

The purpose of the study is to improve the technology for producing gluten-free flaxseed flour and study its chemical composition. Objectives: to develop a technological scheme for producing gluten-free flaxseed flour; to determine the effect of extrusion processing on the chemical composition of gluten-free flaxseed flour, in particular on the protein complex; to determine the moisture-binding ability of flour. Flax seeds are a promising raw material for producing gluten-free flour for the purpose of modeling recipes for bakery and flour confectionery products. Flaxseed flour can be used as a stand-alone product or as an additive to a flour mixture. The developed technology includes additional extrusion processing of flaxseed cake. Due to short-term exposure to high temperature (140 °C), the availability of nutrients and the digestibility of proteins increase, as the native structure of the protein molecule changes. The resulting gluten-free flour is characterized not only by the absence of gluten, but also has a high-quality protein complex containing 17 amino acids, 8 of which are essential and cannot be synthesized by the human body, but enter it only with food. The study found such essential amino acids as lysine (0.72 %), phenylalanine (1.06 %), leucine and isoleucine (1.08 %), methionine (0.43 %), valine (0.97 %). ), threonine (0.89 %) and tryptophan (0.05 %). The total proportion of essential amino acids is 5.20 %. The addition of flax flour to premium wheat flour increases the moisture-binding properties of the flour mixture, which has a positive effect on the quality of the dough, which acquires optimal rheological characteristics, is easily kneaded and shaped.

Autosomal dominant SLURP1 variants cause palmoplantar keratoderma and progressive symmetric erythrokeratoderma

Abstract Background Epidermal differentiation disorders (EDDs, a.k.a. ichthyosis and palmoplantar keratoderma) are severe heritable skin conditions characterized by localized or generalized skin scaling and erythema. Objectives To identify novel genetic variants causing palmoplantar keratoderma (PPK) and progressive symmetric erythrokeratoderma (PSEK) phenotypes. Methods We performed whole exome sequencing in a large EDD cohort including PPK and PSEK phenotypes to identify novel genetic variants. We investigated the variant consequence using in silico predictions, assays in patient keratinocytes, high-resolution spatial transcriptomics, and quantitative cytokine profiling. Results We identified three unrelated kindreds with autosomal dominant transmission of heterozygous SLURP1 variants affecting the same amino acid within the signal peptide (c.65C>A, p.A22D, and c.65C>T, p.A22V). One (p.A22V) had isolated PPK, and two others (p.A22D) had PSEK and PPK. In silico modeling suggested that both variants alter pro-SLURP1 cleavage, appending two amino acids to the secreted protein, which we subsequently confirmed with mass spectrometry. In patient keratinocytes we found increased differentiation-induced SLURP1 expression and secretion compared to healthy control cells. Spatial transcriptomics revealed increased NF-κB signaling and innate immune activity which may contribute to epidermal hyperproliferation in dominant SLURP1-PPK/PSEK. Conclusions Our results expand the phenotypic spectrum of EDD due to SLURP1 pathogenic variants. While autosomal recessive Mal de Meleda is due to biallelic loss-of-function SLURP1 variants, our finding of autosomal dominant SLURP1 pathogenic variants in kindreds with PPK and PSEK suggests a novel mechanism of action. We found that heterozygous p.A22V and p.A22D SLURP1 variants append two amino acids to secreted SLURP1, increase differentiation-induced SLURP1 expression and secretion, and upregulate NF-κB signaling in PSEK cases.

Spanish chickpea gene-bank seeds (Cicer arietinum L.) offer an enhanced nutritional quality and polyphenol profile compared with commercial cultivars.

In the global socioeconomic context and the current climate change scenario, investigating the nutritional and bioactive characteristics of landraces can provide interesting profiles with technological applications and benefits for human health. The purpose of this work was to improve our knowledge regarding the nutritional and phenolic composition of several chickpea accessions preserved in a gene bank compared with widely consumed cultivars, as a first approach to establish their potential nutritional interest. CIELab colour, mineral content, protein, and amino acids were determined, as well as a comprehensive characterization of free and bound phenolic compounds by high-performance liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry. The chickpea accessions displayed a superior macro-mineral profile and higher levels of protein, arginine, and bound phenolic compounds than commercial cultivars did. The total phenolic content ranged from 307.55 to 940.46 μg g-1 dry weight and clearly categorized the crops into desi or kabuli types. The ratio of free to bound phenolic compounds ranged between 2.8 and 50.2 in the kabuli seeds and 0.4-1.3 in the desi type. The most remarkable finding was the quantification of a total of 42 phenolic compounds, nine of them reported for the first time in chickpea seeds (methyl and dimethyl citric acids, glabranin, 3,4-dihydroxy-5-methoxybenzoic acid, myricetin 3-O-rutinoside, dihydromyricetin, phlorizin, kaempferol 7-(6″-p-succinylglucoside) and phloretin). Despite variations in genetic backgrounds and specific agronomic conditions, this research unveils a sufficiently attractive nutritional and phenolic profile to justify further investigations aimed at exploring the future expansion and applications of these chickpea accessions. © 2025 Society of Chemical Industry.

Metabolomic signatures associated with cold adaptation and seasonal acclimation of Drosophila: profiling of 43 species.

Cold tolerance is a key determinant of poleward colonization in insects. However, the physiological basis underlying interspecific differences in cold tolerance is not fully understood. Here, we analyzed cold tolerance and metabolomic profiles in warm- and cold-acclimated phenotypes of 43 Drosophila species representing a latitudinal gradient from the tropics to the boreal zone. We found a strong positive correlation between cold tolerance and climatic variables associated with habitat seasonality and temperature. Including the effects of cold acclimation, we found most species to have similar 'safety margins', measured as the difference between the average environmental temperature and the lower lethal temperature. Searching for metabolomic signatures of cold tolerance, we found that the warm-acclimated flies of cold-hardy species had moderately but significantly higher constitutive signals of putative cryoprotectants such as trehalose, glucose, glycerol, and mannitol/sorbitol. Cold acclimation (and the transition to winter dormant phenotype) resulted in a strong accumulation of myo-inositol, which occurred only in species of the virilis group. Other temperate and boreal species either showed only moderate, idiosyncratic accumulations of sugars/polyols and free amino acids, or did not accumulate any 'classical' cryoprotectant at all. Thus, our results suggest that the colonization of boreal regions by Drosophila does not necessarily depend on the seasonal accumulation of classical cryoprotectants. In contrast, virtually all cold-acclimated species showed a significant increase in products of phospholipid catabolism, suggesting that remodeling of biological membranes is a clear and ubiquitous signature of cold acclimation in Drosophila.

Roles of Vitellogenin and Its Receptor Genes in Female Reproduction of the Cigarette Beetle, Lasioderma serricorne

Vitellogenin (Vg) and the vitellogenin receptor (VgR) play essential roles in insect reproductive development. However, the functions of Vg and VgR genes in Lasioderma serricorne, an important insect pest of stored products, are unknown. We identified and characterized these two genes, designated LsVg and LsVgR, in L. serricorne. The open reading frames of LsVg and LsVgR were 5232 and 5529 bp, encoding 1743 and 1842 amino acid residues, respectively. Both LsVg and LsVgR were predominantly expressed in female adults and exhibited the highest expression in ovaries. The RNAi-mediated silencing of LsVg or LsVgR significantly decreased the average length of ovarian tubes and oocytes and severely affected ovarian development. The Knockdown of LsVg or LsVgR significantly reduced the oviposition period, the number of eggs laid, and the egg hatching rate. Females injected with dsLsVg and dsLsVg + VgR were found to had decreased vitellogenin content. The co-silencing of LsVg and LsVgR had a more pronounced effect on reducing the oviposition period and female fecundity in L. serricorne. This study revealed the importance of LsVg and LsVgR in regulating female reproduction and shows their potential as targets for RNAi-based control of L. serricorne.

Synthesis and Evaluation of Herbicidal Ureidopyrimidine Compounds: Focus on Sulfonamide Modifications.

In this study, 32 novel ureidopyrimidine compounds containing sulfonamide fragments were strategically designed and synthesized through active substructure combination. Postemergence herbicidal activity assays demonstrated that compounds 13a, 14d, and 15c exhibited superior efficacy against broadleaf weeds, including Zinnia elegans and Abutilon theophrasti, with compound 15c achieving a remarkable 95% control rate at 9.375 g a.i./ha, comparable to that of the commercial herbicide saflufenacil. Molecular docking simulations revealed that these compounds, along with saflufenacil, establish hydrogen bonds with protoporphyrinogen oxidase, particularly involving important amino acid residues, including ARG-98, GLY-175, and ASN-67. Structure-activity relationship analysis, supported by density functional theory calculations and molecular electrostatic potential studies, highlighted the importance of negatively charged regions in herbicidal activity. This comprehensive research provides valuable insights into the design and development of potent herbicides, establishing a strong foundation for future advancements in agricultural chemistry.

Phenolic and amino acid profiles, and antioxidant properties of third generation snack foods adding Citrus mitis by-products and milk powder: impact of extrusion processing and microwave-heating “Impact of processing on obtaining healthy snacks”

Currently, there is a high consumption of snack foods worldwide, suggesting the improvement of their nutritional/nutraceutical properties by adding raw materials rich in bioactive compounds. This work aimed to study the impact of the processing stages on phenolic and amino acid profiles and the antioxidant properties of extruded snack foods by adding Citrus mitis by-products and milk powder. The color parameter C*, phytochemical, and antioxidant properties of four formulations were evaluated in the processing stages: unprocessed mixture (PS1), extruded pellets (PS2), and microwave-expanded products (PS3). The statistical analysis was performed using an unifactorial design with three levels (PS1, PS2, and PS3), evaluating four formulations (F1–F4) and a commercial product (COM). The mean values of the response variables were compared using the Fisher test (p ≤ 0.05). Color parameter C* increased in PS3 concerning the PS2 and PS1 processing stages. Total flavonoid content (TFC), hydroxyl radical scavenging activity (HRSA), and inhibition of human LDL oxidation (ILDLox) decreased in PS2 regarding PS1. Likewise, TFC decreased in PS3 regarding PS2, whereas HRSA and ILDLox increased. PS3 exhibited higher TFC, HRSA, and ILDLox values in all formulations regarding commercial snack foods. Sixteen phenolic acids, nine flavonoids, and a hydroxy acid were identified in free and bound extracts by UPLC coupled to ESI-MS. The amino acid profile was affected by processing, and Lysine showed the lowest stability. The microwave-expanded snack foods had acceptable sensory properties evaluated by consumers, and adding raw materials rich in phytochemical compounds and high-quality proteins enhanced their nutraceutical/nutritional properties.

ВЛИЯНИЕ АМИНОКИСЛОТНЫХ ПРЕПАРАТОВ НА РАССАДУ КОСМЕИ ДВАЖДЫПЕРИСТОЙ И СЕРНО-ЖЕЛТОЙ

The purpose of research is to study the effect of amino acid preparations on the quality of cosmos seedlings. For this purpose, the following tasks were solved: indicators of the average trend in the parameters of seedlings of two types of Cosmos were established; the contribution of varietal characteristics and preparations to seedling parameters was assessed; The reliability of the differences between the experimental variants was established. We used varieties of double-pinnate Cosmea (lat. Cosmos bippinatus) – Popsoks rozovyj, Limonad, Snezhnyj klik and variety of Cosmea serno-zheltaj (lat. Cosmos sulphureus) Zolotaya dolina. We tested the amino acid preparations Stimul Antistress and Aminozol. Measurements were carried out on such parameters as shoot height, plant height, number of leaves, stem thickness in the first internode. To analyze statistical data, methods of descriptive statistics, analysis of variance and the method of pairwise differences of group means with NSR05 were used. It was established that the Snezhnyj klik variety showed minimal germination, and further studies were not carried out on this variety. The most leveled seedlings of the Limonad variety in height are achieved when treated with Stimul and Aminosol (variation coefficient 14.5 and 15 %), the Popsoks rozovyj variety – in the control variant (11.8 %) and with Stimul Antistress (14 %), the Zolotaya dolina variety gives homogeneous plants without treatment and with Aminosol (12.3 and 12.4 %). Analysis of variance of the parameters of the Cosmos double-pinnate varieties showed that the drugs do not significantly affect the height of the shoot, but they affect the number of leaves and the thickness of the stem in the first internode by 13 % (49 %). When assessing the effect of drugs on cosmos species, it turned out that they only affect the thickness of the stem (by 35 %). Due to the low influence of drugs on the uniformity of seedling parameters, we consider further use of drugs to be ineffective specifically for cosmos species and varieties.

Perspectives on Diet and Exercise Interaction for Healthy Aging: Opportunities to Reduce Malnutrition Risk and Optimize Fitness

Nutrition and exercise play a pivotal role in counteracting the effects of aging, promoting health, and improving physical fitness in older adults. This perspective study examines their interplay, highlighting their combined potential to preserve muscle mass, cognitive function, and quality of life. The objective is to address gaps in the current understanding, such as the frequent neglect of dietary intake in exercise interventions and vice versa, which can limit their effectiveness. Through a synthesis of the existing literature, we identify key findings, emphasizing the importance of adequate nutritional intake—particularly protein, essential amino acids, and micronutrients—in supporting exercise benefits and preventing sarcopenia and malnutrition. Additionally, supplementation strategies, such as omega-3 fatty acids, creatine, and essential amino acids, are explored alongside the emerging role of the gut microbiota in mediating the benefits of nutrition and exercise. Despite these advances, challenges remain, including determining optimal dosages and timing and addressing individual variability in responses. Personalized approaches tailored to sex differences, gut microbiota diversity, and baseline health conditions are critical for maximizing intervention outcomes. Our conclusions underscore the necessity of integrated strategies that align dietary and exercise interventions to support healthy and active aging. By addressing these gaps, future research can provide actionable insights to optimize health and quality of life in older populations.

Biosynthesis of unique natural product scaffolds by Fe(II)/αKG-dependent oxygenases

Abstract Fe(II)/αKG-dependent oxygenases are multifunctional oxidases responsible for the formation of unique natural product skeletons. Studies of these enzymes are important because the knowledge of their catalytic functions, enzyme structures, and reaction mechanisms can be used to create non-natural enzymes through mutation and synthesize non-natural compounds. In this review, I will introduce the research we have conducted on two fungal Fe(II)/αKG-dependent oxygenases, TlxI-J and TqaL. TlxI-J is the first Fe(II)/αKG-dependent oxygenase type enzyme heterodimer that catalyzes consecutive oxidation reactions, hydroxylation followed by retro-aldol or ketal formation, to form the complex skeletons of meroterpenoids. TqaL is the first naturally occurring aziridine synthase, and I will discuss the mechanism of its unique C–N bond formation in nonproteinogenic amino acid biosynthesis. This review will advance research on the discovery of new enzymes and the analysis of their functions by reviewing the structures and functions of these extraordinary Fe(II)/αKG-dependent oxygenases, and promote their use in the synthesis of new natural medicines. Graphical Abstract

Protein codes promote selective subcellular compartmentalization

Cells have evolved mechanisms to distribute ~10 billion protein molecules to subcellular compartments where diverse proteins involved in shared functions must assemble. Here, we demonstrate that proteins with shared functions share amino acid sequence codes that guide them to compartment destinations. A protein language model, ProtGPS, was developed that predicts with high performance the compartment localization of human proteins excluded from the training set. ProtGPS successfully guided generation of novel protein sequences that selectively assemble in the nucleolus. ProtGPS identified pathological mutations that change this code and lead to altered subcellular localization of proteins. Our results indicate that protein sequences contain not only a folding code, but also a previously unrecognized code governing their distribution to diverse subcellular compartments.

A rare deleterious missense mutation in the AXIN2 gene in Chinese women with polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is an endocrine disorders and characterized by polycystic ovary morphology and oligomenorrhea, affecting fertility and health condition of female around the world. The causative factors of PCOS are complex, and genetic structure remains a long-standing medical challenge in genetics. Previous genome-wide association study (GWAS) showed that Wing-less-related integration site (Wnt) signaling is the most affected pathway among PCOS-related risk genes, and genetic mutations in the Wnt/β-catenin signaling may lead to abnormal development of PCOS. To explore the possibility of axis inhibitor-2 (AXIN2) variants in Chinese women with PCOS and assess their pathogenicities. A total of 365 Chinese women with PCOS and 905 women without PCOS as control were recruited from Jiangxi Provincial Maternal and Child Health Hospital, All of the 11 exons and flanking regions of the AXIN2 gene were amplified by polymerase chain reaction (PCR), the potential variants were analyzed by Sanger sequencing. The evolutionary conservation analysis of the identified Axin-2 mutant was analyzed among 15 vertebrates from human to zebrafish. The protein structure change was analyzed between the wild-type and mutation-type. The pathogenicity of AXIN2 variant was further analyzed in silico. We totally identified 7 genetic variants of AXIN2 in this study, including 4 synonymous and 3 missense. Among them, we find a rare deleterious missense variant [p.R714W (c.2140C > T)]. The allele frequencies of this variant were 0.82% and 0.17% in PCOS cases and matched controls, respectively. And it was ranging from 7.89e-5 to 1.47e-4 in public databases. Fisher's exact test indicated that the allele frequencies in PCOS were p < 0.05 compared to both the controls and the databases. Especially, the mutant amino acid site is highly conserved in vertebrates, while the mutation changed the 714th arginine to tryptophan resulting in significant change in the protein structural of Axin-2. In this study, we identified a rare deleterious missense AXIN2 mutation [p.R714W (c.2140C > T)] in Chinese women with PCOS, and this mutant is probably pathogenic. This study may provide a new perspective on revealing the genetic variation of PCOS.

Effects of Cryoprotectants on the Physicochemical Properties of Bonito (Sarda sarda) Fillets Subjected to Multiple Freeze–Thaw Cycles

ABSTRACT In this study, bonito (Sarda sarda) fillets were treated with sucrose-sorbitol, sodium tripolyphosphate, and sodium alginate as cryoprotectants before freezing to prevent changes in fish muscle during multiple freezing cycles and frozen storage. Lower soluble protein contents were determined in cryoprotectant-treated groups than in the control group. Lower polar and non-polar free amino acid contents were determined with the sodium tripolyphosphate group in the last cycle compared to the other groups. Cryoprotectant-added fillets had higher water-holding capacity and lower hardness values than the control. It was determined that the most effective cryoprotectant was sodium tripolyphosphate.

Epitope mapping of recombinant Salmonella enterica serotype Heidelberg flagellar hook-associated protein by in silico and in vivo approaches

Abstract Background Salmonella is a leading cause of human acute bacterial gastroenteritis worldwide. Outbreaks of human salmonellosis have often been associated with consumption of contaminated poultry products. Various strategies have been explored to control this microorganism during poultry production and processing. Vaccination of broiler chickens is regarded as one of the effectives means to control this microorganism. The aim of the present study was to compare the epitope identification in the Salmonella enterica serotype Heidelberg FlgK protein by in silico prediction and in vivo experiment with mass spectrometry in association with immunoprecipitation proteomics. Results The Salmonella serotype Heidelberg FlgK protein contains 553 amino acids with a molecular mass of 61 kDa. This protein is conserved among Salmonella serotype Heidelberg isolates. The results show that both approaches identified three common shared consensus peptide epitope sequences at the positions of 77–95, 243–255 and 358–373 in the Salmonella serotype Heidelberg FlgK protein. Conclusions These findings provide a rational for further evaluation of these shared linear epitopes in vaccine development to cover the chicken population.

Genetic Code Expansion for Controlled Surfactin Production in a High Cell-Density Bacillus subtilis Strain

Background: In biotechnology, B. subtilis is established for heterologous protein production. In addition, the species provides a variety of bioactive metabolites, including the non-ribosomally produced surfactin lipopeptide. However, to control the formation of the target product-forming enzyme, different expression systems could be introduced, including the principle of genetic code expansion by the incorporation of externally supplied non-canonical amino acids. Methods: Integration of an amber stop codon into the srfA operon and additional chromosomal integration of an aminoacyl-tRNA synthetase/tRNA mutant pair from Methanococcus jannaschii enabled site-directed incorporation of the non-canonical amino acid O-methyl-L-tyrosine (OMeY). In different fed-batch bioreactor approaches, OMeY-associated surfactin production was quantified by high-performance thin-layer chromatography (HPTLC). Physiological adaptations of the B. subtilis production strain were analyzed by mass spectrometric proteomics. Results: Using a surfactin-forming B. subtilis production strain, which enables high cell density fermentation processes, the principle of genetic code expansion was introduced. Accordingly, the biosynthesis of the surfactin-forming non-ribosomal peptide synthetase (NRPS) was linked to the addition of the non-canonical amino acid OMeY. In OMeY-associated fed-batch bioreactor fermentation processes, a maximum surfactin titre of 10.8 g/L was achieved. In addition, the effect of surfactin induction was investigated by mass spectrometric proteome analyses. Among other things, adaptations in the B. subtilis motility towards a more sessile state and increased abundances of surfactin precursor-producing enzymes were detected. Conclusions: The principle of genetic code expansion enabled a precise control of the surfactin bioproduction as a representative of bioactive secondary metabolites in B. subtilis. This allowed the establishment of inducer-associated regulation at the post-transcriptional level with simultaneous use of the native promoter system. In this way, inductor-dependent control of the production of the target metabolite-forming enzyme could be achieved.

L-Theanine Metabolism in Tea Plants: Biological Functions and Stress Tolerance Mechanisms

L-theanine, a unique non-protein amino acid predominantly found in tea plants (Camellia sinensis), plays a pivotal role in plant responses to abiotic stress and significantly influences tea quality. In this review, the metabolism and transport mechanisms of L-theanine are comprehensively discussed, highlighting its spatial distribution in tea plants, where it is most abundant in young leaves and less so in roots, stems, and older leaves. The biosynthesis of L-theanine occurs through the enzymatic conversion of glutamate and ethylamine, catalyzed by theanine synthase, primarily in the roots, from where it is transported to aerial parts of the plant for further catabolism. Environmental factors such as temperature, light, drought, elevated CO2, nutrient unavailability, and heavy metals significantly affect theanine biosynthesis and hydrolysis, with plant hormones and transcription factors playing crucial regulatory roles. Furthermore, it has been demonstrated that applying L-theanine exogenously improves other crops’ resistance to a range of abiotic stresses, suggesting its potential utility in improving crop resilience amid climate change. This review aims to elucidate the physiological mechanisms and biological functions of L-theanine metabolism under stress conditions, providing a theoretical foundation for enhancing tea quality and stress resistance in tea cultivation.

Green Synthesis of Copper Nanoparticles utilising the Maillard Reaction.

A new approach for the fabrication of copper nanoparticles by a wet chemical reduction method is reported. The natural resources arginine as amino compound and several monosaccharides (xylose, ribose, galactose and glucose) react characteristically performing an Amadori rearrangement followed by a Maillard type reaction. This reaction carried out in an aqueous solution ensures an environmentally friendly way to reduce copper(II) ions leading to the formation of the desired nanoparticles. By changing the concentration of the amino acid, simultaneously acting as a complexing agent, it is possible to tune the size of the resulting nano particles to a certain degree down to 3 nm. This nontoxic and facile preparation route with quantitative yield opens a wide field of applications ranging from electronics to medical approaches.

The role of FTO in m6A RNA methylation and immune regulation in Staphylococcus aureus infection-related osteomyelitis

BackgroundRegulators of n6-methyladenosine (m6A) RNA modification play important roles in many diseases; however, their involvement in Staphylococcus aureus (S. aureus)-related osteomyelitis remains inadequately explored. Therefore, this study aims to investigate the role of m6A in S. aureus infection-related osteomyelitis and elucidate its underlying mechanisms.MethodsWe downloaded the S. aureus infection-related osteomyelitis infection dataset GSE30119 from the Gene Expression Omnibus database. Initially, we constructed a diagnostic model based on m6A genes and predicted the hub node miRNAs and transcription factors by constructing a protein–protein interaction network. Subsequently, a prognostic model was built using LASSO regression, the receiver operating characteristic curve of the model was plotted, and the predictive performance of the diagnostic model was validated. Further, unsupervised clustering analysis, gene set enrichment analysis (GSEA), and gene set variation analysis (GSVA) were employed to assess immune cell infiltration. Additionally, we validated the expression of fat mass and obesity-associated protein (FTO) in S. aureus-infected Raw264.7 macrophages using qPCR and western blotting. Moreover, we conducted si-FTO experiments on mouse Raw264.7 macrophages to investigate the anti-inflammatory regulatory role of si-FTO during S. aureus infection.ResultsWe identified 19 co-expressed genes closely related to FTO were identified, along with 206 related transcription factor regulatory genes and 589 miRNAs. Enrichment analyses suggested that these genes were involved in pathways related to the proliferation and oxidation of various immune cells, cellular senescence, and various tumors and immune cells, as well as cell cycle-related functions. GSEA revealed that PD-1, TH1, TH2, CTLA4, and other pathways were significantly enriched in patients with high FTO expression. GSVA indicated that the differentially enriched pathways were related to included amino acid metabolism, immunity, and infection. Correlation analysis of immune infiltration revealed that monocytes, M2 macrophages, resting mast cells, and neutrophils were present in normal and diseased samples. Differences in expression were observed between the groups. The western blotting and qPCR analyses confirmed that the protein expression of FTO was reduced in macrophages after infection with S. aureus, consistent with the observed changes in mRNA expression. Furthermore, we validated that FTO may influence the regulation of inflammation through the FoxO1/NF-kB pathway.ConclusionThe m6A RNA methylation regulator FTO may serve as a potential diagnostic marker and therapeutic target, involved in the pathogenesis of S. aureus infection-related osteomyelitis. This finding provides new insights into the relationship between FTO-mediated m6A RNA methylation and osteomyelitis.