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Increasing global life expectancy motivates investigations of molecular mechanisms of aging and age‐related diseases. This study examines age‐associated changes in red blood cells (RBCs), the most numerous host cell in humans. Four cohorts, including healthy individuals and patients with sickle cell disease, were analyzed to define age‐dependent changes in RBC metabolism. Over 15,700 specimens from 13,757 humans were examined, a major expansion over previous studies of RBCs in aging. Multi‐omics approaches identified chronological age‐related alterations in the arginine pathway with increased arginine utilization in RBCs from older individuals. These changes were consistent across healthy and sickle cell disease cohorts and were influenced by genetic variation, sex, and body mass index. Integrating multi‐omics data and metabolite quantitative trait loci (mQTL) in humans and 525 diversity outbred mice functionally linked metabolism of arginine during RBC storage to increased vesiculation—a hallmark of RBC aging—and lower post‐transfusion hemoglobin increments. Thus, arginine metabolism is a biomarker of RBC and organismal aging, suggesting potential new targets for addressing sequelae of aging. [ABSTRACT FROM AUTHOR]

Purpose: The study explored the enhanced skin moisturizing capabilities and moisture retention effects achieved by forming a polyion complex using sulfated glycosaminoglycan (GAG), specifically chondroitin sulfate (CS), and amino acids (AA) such as glutamine (Q) and arginine (R). The overall hydration effect of this CS‐AA complex was examined. Methods: After analyzing the CS‐AA polyion complex structure using spectroscopic methods, the ex vivo moisture retention ability was assessed under dry conditions using porcine skin samples. Additionally, the efficacy of the CS‐AA polyion complex in reducing transepidermal water loss (TEWL) and improving skin hydration was evaluated on human subjects using a digital evaporimeter and a corneometer, respectively. Results: Validating a systematic reduction in particle size, the following order was observed: CS > CS/AA simple mixture > CS‐AA complex based on dynamic light scattering (DLS) and transmission electron microscopy (TEM) analysis. Furthermore, observations revealed that the CS‐AA complex exhibits negligible surface charge. Additionally, Fourier‐transform infrared spectroscopy (FT‐IR) analysis demonstrated a distinct peak shift in the complex, confirming the successful formation of the CS‐AA complex. Subsequently, the water‐holding effect through porcine skin was assessed, revealing a notable improvement in moisture retention (weight loss) for the CS‐Q complex: 40.6% (1 h), 20.5% (2 h), and 18.7% (4 h) compared to glycerin. Similarly, the CS‐R complex demonstrated enhancements of 50.2% (1 h), 37.5% (2 h), and 33% (4 h) compared to glycerin. Furthermore, TEWL improvement efficacy on human skin demonstrated approximately 25% improvement for both the CS‐Q complex and CS‐R complex, surpassing the modest 12.5% and 18% improvements witnessed with water and glycerin applications, respectively. Finally, employing a corneometer, hydration changes in the skin were monitored over 4 weeks. Although CS alone exhibited nominal alterations, the CS‐Q complex and CS‐R complex showed a significant increase in moisture levels after 4 weeks of application. Conclusion: In this study, polyion complexes were successfully formed between CS, a sulfated GAG, and AA. Comparisons with glycerin, a well‐known moisturizing agent, confirmed that the CS‐AA complex exhibits superior moisturizing effects in various aspects. These findings suggest that the CS‐AA complex is a more effective ingredient than CS or AA alone in terms of efficacy. [ABSTRACT FROM AUTHOR]

Summary: In this study, we examined the physicochemical and functional properties of fava bean globulin fractions that are rich in legumin or vicilin proteins. The sulphur containing amino acids, branched chain amino acids, and arginine/lysine ratio obtained for legumin (1.89%, 18.32%, and 1.43%) are significantly (P < 0.05) higher than the 1.24%, 17.94%, and 1.05%, respectively, for the vicilin fraction. SDS‐PAGE results show that the legumin fraction had a wider range of polypeptide sizes (approximately 14–140 kDa) when compared to the approximately 12–68 kDa for vicilin. The surface hydrophobicity (So) of legumin (86.07) was significantly (P < 0.05) lower compared with vicilin (118.19). The legumin had higher protein solubility (approximately 40–50%) than the vicilin (0%) at pH 3 and 4, but vicilin solubility was higher at pH 6–8. The vicilin had higher (83.58%) in vitro protein digestibility than the legumin (78.24%). However, the legumin had higher oil‐holding capacity, lower least gelation concentration, and formed emulsions at pH 3, 7, and 9 with smaller mean oil droplet sizes than the vicilin. Foam formation was better with increased levels of α‐helix secondary structure. We conclude that pH of the environment was a stronger determinant of protein functionality than the sample protein concentration. [ABSTRACT FROM AUTHOR]

BACKGROUND: Energy‐saving and low‐carbon baking processes, as well as the need to determine the flavor‐forming mechanisms of baked dried tofu, are becoming increasingly necessary. The application of emerging catalytic infrared radiation (CIR) technology in baking of dried tofu is considered of high interest due to the low energy consumption and high baking efficiency compared to traditional baking methods. Hence, this study aimed to investigate the evolution of aroma compounds in baked dried tofu during the CIR baking process and reveal relevant relationships between physical qualities, potential flavor precursors and key volatile compounds. RESULTS: The results showed that the surface color of dried tofu gradually turned an appetizing golden yellow color during the rapid heating process, caused by the uniform infrared radiation from the radiant emitters. Meanwhile, the moisture of dried tofu experienced minimal reduction and the hardness of dried tofu gradually increased with the formation of crust on the surface. In addition, 49 volatile compounds were identified by headspace solid‐phase microextraction–gas chromatography–mass spectrometry and 13 substances – 1‐hexanol, 1‐octen‐3‐ol, 1‐pentanol, heptanal, nonanal, hexanal, (E,E)‐2,4‐decadienal, (E,Z)‐2,4‐decadienal, octanal, (E)‐2‐octenal, (E)‐2‐nonenal, 2‐heptanone and 2‐pentylfuran – were confirmed as key aroma compounds. Moreover, the amino acids aspartic acid, glutamic acid, isoleucine, lysine and arginine, and the fatty acids butyric, caprylic, capric, tridecanoic, stearic, oleic and linolenic were responsible for the unique flavor of CIR‐baked dried tofu. CONCLUSION: Consequently, the findings can provide a scientific basis for manufacturers to achieve precise quality control and large‐scale production of CIR‐baked dried tofu products. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Amino acids and their salts are amine compounds with great potential for the chemical absorption of CO2 via the amine method. The CO2 absorption properties of various amino acids and their salts have been previously reported. However, the detailed reaction mechanism of CO2 with basic amino acids in aqueous solutions has not yet been clarified. In this study, we focused on arginine (Arg), which has the highest basicity among the standard amino acids, and its monohydrochloride (ArgCl) and sodium (NaArg) salts for the dissolution of CO2 in the aqueous solutions of Arg, ArgCl, and NaArg. CO2 was chemically dissolved in aqueous Arg and NaArg solutions but not in the aqueous ArgCl solution. One‐dimensional 1H and 13C and two‐dimensional 1H‐13C heteronuclear multiple bond correlation nuclear magnetic resonance spectroscopy indicated that the final products in the aqueous Arg and NaArg solutions were protonated Arg and HCO3−. HCO3− was formed from both CO2‐bonded Arg/Arg− and CO32− intermediates in the aqueous NaArg solution but only from the CO2‐bonded Arg/Arg− intermediate in the aqueous Arg solution. In addition to their high environmental and biological compatibility, Arg and NaArg exhibit high CO2 absorption capacity, demonstrating their potential for practical use as naturally derived CO2 chemical absorbents. [ABSTRACT FROM AUTHOR]

Summary: The study inquired the influences of l‐arginine and l‐lysine on the physicochemical properties (including weight loss rate, water activity, texture, colour, lipid and protein oxidation, residual nitrite content and total volatile basic nitrogen (TVB‐N) content) of low‐sodium and low‐phosphate Cantonese sausage during the 1‐ and 7‐day storage. The results showed that the addition of l‐arginine or l‐lysine reduced the weight loss rate, TBARS content, carbonyl group content and residual nitrite level, slightly decreased water activity, and enhanced L*, a* and b* values. Compared to the control, 0.3% l‐arginine or l‐lysine declined hardness and chewiness, while 0.6% l‐arginine or l‐lysine elevated these two parameters. However, the addition of l‐arginine or l‐lysine also led to an increase in TVB‐N content. Overall, l‐arginine and l‐lysine improved the qualities of low‐sodium and low‐phosphate Cantonese sausage, which might be attractive to meat product manufacturers. [ABSTRACT FROM AUTHOR]

Objective: In this study, dentine surface was analysed through Environmental‐scanning‐electron‐microscopy (ESEM) with energy‐dispersive‐X‐ray‐spectrometry (EDX) and Fourier‐transform‐infrared‐spectroscopy (FTIR) with attenuated total‐reflectance (ATR) to assess the morpho‐chemical changes and variations in mineralization degree after demineralizing treatment, after five toothpastes application (HA & Citrate toothpaste, Zinc‐HA toothpaste, Calcium Sodium Phosphosilicate toothpaste, Arginine & Calcium carbonate toothpaste, Colgate‐Triple‐Action, and Control toothpaste), after soaking in artificial saliva and after citric acid attack. Methods: Ca/P, Ca/N and P/N ratios were calculated from EDX atomic data to evaluate the mineralization degree of dentine surface. The IR calcium phosphate (CaP)/collagen and carbonate/collagen ratios has been evaluated to assess the remineralization changes in dentine; the carbonate/collagen IR ratio was calculated to identify the nucleation of B‐type‐carbonated apatite and calcium carbonate. Results: ESEM–EDX and ATR–FTIR showed residuals of toothpastes after the treatments in all cases, with a general increase in the mineralization degree after soaking in artificial saliva and a decrease after acid attack. Treatment with Arginine & Calcium carbonate toothpaste showed the highest Ca/P value after treatment (Ca/P 1.62) and acid attack (Ca/P 1.5) in confirmation, IR showed the highest amount of carbonate after treatment and soaking in artificial saliva. Arginine and calcium carbonate toothpaste and HA and citrate toothpaste remained to a higher extent on the dentine surface and revealed a higher remineralization activity. These formulations showed higher resistance to demineralization attack, as demonstrated by a higher ICaP/IAmide II intensity ratio than those obtained after EDTA treatment. Conclusions: Toothpastes that remained to a higher extent on dentine surface (arginine and calcium carbonate toothpaste in particular) were more able to promote remineralization. The formed calcium phosphate (CaPs) phase was intimately bound to dentine rather than a simple deposit. [ABSTRACT FROM AUTHOR]

A simple, solvent‐free arginine‐catalyzed aldol dimerization of levulinic acid was achieved via the simultaneous formation of a eutectic mixture. Dimers of levulinic acid are valued as biomass‐derived fine chemical precursors, with potential to upgrade to bio‐jet fuels or N‐containing functional chemicals. Typically, these dimers are produced as isomeric mixtures using high temperatures and a variety of solid inorganic catalysts or mineral acids. In this study, an organocatalytic and regioselective dimerization was achieved at 22 % conversion on either a bench or kilogram scale using mild temperatures and only L‐arginine as both a co‐solvent and catalyst. The intricate H‐bonding network comprising the eutectic solvent was harnessed to produce only one product, minimizing side reactivity and preserving the reactants for recycling. [ABSTRACT FROM AUTHOR]

Cation‐π interactions, often found in protein assemblies, are characterized by favorable electrostatic interactions between an aromatic π‐electron surface and a positively charged species. There are evidences that reveal the importance of cation‐π interactions between arginine and aromatic residues in protein structure and function. In this paper, the effect of cation‐π interactions on the aggregation propensity of peptides derived from human islet polypeptide (hIAPP) was explored using UV resonance Raman and fluorescence spectroscopy. By employing an analog of hIAPP22–29 in which Phe‐23 is replaced with tryptophan (NWGAILSS), we were able to demonstrate an increase in the amyloidogenic propensity of this mutant in the presence of Zn2+ that is attributable to cation‐π interactions. In contrast, no cation‐π interactions were observed when the cationic F23R analog of hIAPP22–29 (NRGAILSS) was allowed to interact with NWGAILSS. From these observations, it was surmised that in these peptides, the dominant interaction between arginine and tryptophan involves the π‐cloud of the guanidino group and the indole ring, not cation‐π interactions. The spectroscopic data, supported by density functional theory‐based simulation results, suggest that arginine‐tryptophan interaction involves π‐π stacking where the guanidino group is oriented parallel to the indole ring. These hydrophobic interactions, coupled with the hydrotropic effect of the guanidine functionality of arginine, led to a delay in the aggregation kinetics of NWGAILSS. These unique interactions were further exploited to design a peptide inhibitor of full‐length amylin self‐assembly. [ABSTRACT FROM AUTHOR]

Aquaporin‐2 (AQP2) is a member of the aquaporin water channel family. In the kidney, AQP2 is expressed in collecting duct principal cells where it facilitates water reabsorption in response to antidiuretic hormone (arginine vasopressin, AVP). AVP induces the redistribution of AQP2 from intracellular vesicles and its incorporation into the plasma membrane. The plasma membrane insertion of AQP2 represents the crucial step in AVP‐mediated water reabsorption. Dysregulation of the system preventing the AQP2 plasma membrane insertion causes diabetes insipidus (DI), a disease characterised by an impaired urine concentrating ability and polydipsia. There is no satisfactory treatment of DI available. This review discusses kinases that control the localisation of AQP2 and points out potential kinase‐directed targets for the treatment of DI. [ABSTRACT FROM AUTHOR]

Cancer is increasingly acknowledged as a metabolic disease, characterized by metabolic reprogramming as its hallmark. However, the precise mechanisms behind this phenomenon and the factors contributing to tumorigenicity are still poorly understood. In a recent publication in Cell, Mossmann and colleague reported a study unveiling arginine as a molecule with second messenger‐like properties that reshapes metabolism to facilitate the tumor development in hepatocellular carcinoma (HCC). Their research revealed that the RNA‐binding motif protein 39 (RBM39)‐mediated increase in asparagine synthesis results in increased arginine uptake. This establishes a positive feedback loop that sustains elevated levels of arginine and facilitates oncogenic metabolic reprogramming. Additionally, Mossmann et al. demonstrated that depleting RBM39 with indisulam effectively disrupts the proto‐oncogenic metabolic reprogramming in HCC. This discovery presents a novel treatment strategy for arginine‐dependent liver cancers. [ABSTRACT FROM AUTHOR]

ABSTRACT This review examines the potential applications of peptides in biotechnology, medicine, and pharmacy, while highlighting the important antibacterial and antiviral properties of peptides. Peptides and chemical peptide synthesis have become a field of study that is gaining great momentum today. Some of the main reasons for this are high specificity, biodegradability and versatility of peptides. Peptides also have some specific properties that make them attractive for pharmaceutical development. As a case study, it can be used to create peptides that can be used to replace or fix damaged proteins in the body by mimicking the action of naturally occurring proteins. Delivering drugs or other therapeutic agents to specific cells or tissues is another method that can help increase the effectiveness of treatment and reduce unwanted effects. Various types of antimicrobial peptides (AMPs), such as defensins and cathelicidins, and their anti‐infective properties are also discussed. Finally, peptides (melittin, lactoferricin, etc.) can be used to trigger an immune response against certain infections, such as COVID‐19 and Zika virus, by acting as vaccines. In our study, a comprehensive review was made on antiviral and AMPs, and especially peptides containing arginine and lysine were mentioned. The properties of these peptides, examples of these peptides and their developments in the pharmaceutical field are emphasized. [ABSTRACT FROM AUTHOR]

Acid‐induced arginine decarboxylase AdiA is a typical homo‐oligomeric protein biosynthesizing alkaline nylon monomer putrescine. However, upon loss of the AdiA decamer oligomeric state at neutral and alkaline conditions the activity also diminishes, obstructing the whole‐cell biosynthesis of alkaline putrescine. Here, a structure cohesion strategy is proposed to change the pH adaptation of AdiA to alkaline environments based on the rational engineering of meridional and latitudinal oligomerization interfaces. After integrating substitutions of E467K at the latitudinal interface and H736E at the meridional channel interface, the structural stability of AdiA decamer and its substrate transport efficiency at neutral and alkaline conditions are improved. Finally, E467K_H736E is well adapted to neutral and alkaline environments (pH 7.0–9.0), and its enzymatic activity is 35‐fold higher than that of wild AdiA at pH 8.0. Using E467K_H736E in the putrescine synthesis pathway, the titer of putrescine is up to 128.9 g·L−1 with a conversion of 0.94 mol·mol−1 in whole‐cell catalysis. Additionally, the neutral pH adaptation of lysine decarboxylase, with a decamer structure similar to AdiA, is also improved using this cohesion strategy, providing an option for pH‐adaptation engineering of other oligomeric decarboxylases. [ABSTRACT FROM AUTHOR]

Objective: The mechanism of asymmetric dimethylarginine (ADMA) in thrombosis in patients with nonvalvular atrial fibrillation (NVAF) is still unclear. Our aim was to investigate the relationship between ADMA and indicators of prethrombotic state in NVAF patients and to analyze the predictive role of ADMA in NVAF thrombosis. Methods: A total of 192 NVAF patients were continuously selected from January 2023 to October 2023. Plasma ADMA levels were measured by high‐performance liquid chromatography. P‐selectin (P‐sel), von Willebrand factor (vWF), D‐dimer (D‐D), and plasminogen activator inhibitor‐1 (PAI‐1) levels were measured by enzyme‐linked immunosorbent assay (ELISA). Nitric oxide (NO) levels were measured by the nitrate reductase assay for plasma nitrite/nitrate, then the Griess method (Shanghai Hailian Biotechnology Co., Shanghai, China) was used to calculate plasma NO levels. Results: In our study, ADMA levels were significantly elevated and positively correlated with P‐sel, vWF, D‐D, and PAI‐1, whereas NO levels were significantly negatively correlated with these prethrombotic factors in NVAF. Furthermore, multifactorial logistic regression analysis showed that ADMA and LA diameter were independent predictors of high thrombosis risk (CHA2DS2‐VASc ≥2 score) in patients with NVAF. Conclusions: Our findings suggested that ADMA correlated with the prethrombotic state in NVAF and that reduction of ADMA levels in NVAF patients may be a novel therapeutic strategy for thrombosis risk reduction. [ABSTRACT FROM AUTHOR]

The cathode interlayer (CIL) plays a crucial role in organic solar cells (OSCs), which can establish an Ohmic contact between the active layer and the electrode, lower the electron extraction barriers, and minimize the charge carrier recombination. The CIL modification is a useful strategy for improving the performance of OSCs. Herein, an inexpensive water–alcohol‐soluble material known as L‐Arginine (L‐Arg) is introduced as a modifier for the PFN‐Br CIL, leading to successful optimization of the CIL quality. Following L‐Arg modification, the work function of the CIL is lowered and the electron extraction is facilitated. L‐Arg assists in exciton dissociation while suppressing both bimolecular and trap‐assisted recombination processes. The modified CIL establishes superior contact with the metal electrode due to its enhanced hydrophilicity, which helps electron collection. Consequently, the average power conversion efficiency increases from 10.54% in the reference device to 11.17% in the optimally doped device. [ABSTRACT FROM AUTHOR]

Polyionic liquid hydrogels attract increasing attention due to their unique properties and potential applications. However, research on amino acid‐based polyionic liquid hydrogels is still in its infancy stage. Moreover, the effect of amino acid types on the properties of hydrogels is rarely studied to date. In this work, amino acid‐based polyionic liquid hydrogels (D/L‐PCAA hydrogels) are synthesized by copolymerizing vinyl choline–amino acid ionic liquids and acrylic acids using Al3+ as a crosslinking agent and bacterial cellulose (BC) as a reinforcing agent. The effects of amino acid types on mechanical and antimicrobial properties are systematically investigated. D‐arginine‐based hydrogel (D‐PCArg) shows the highest tensile strength (220.7 KPa), D‐phenylalanine‐based hydrogel (D‐PCPhe) exhibits the highest elongation at break (1346%), and L‐aspartic acid‐based hydrogel (L‐PCAsp) has the highest elastic modulus (206.9 KPa) and toughness (1.74 MJ m−3). D/L‐PCAsp hydrogels demonstrate stronger antibacterial capacity against Escherichia coli and Staphylococcus aureus, and D/L‐PCPhe hydrogels possess higher antifungal activity against Cryptococcus neoformans. Moreover, the resultant hydrogels exhibit prominent hemocompatibility and low toxicity, as well as excellent self‐healing capabilities (86%) and conductivity (2.8 S m−1). These results indicate that D/L‐PCAA hydrogel provides a promise for applications in wound dressings. [ABSTRACT FROM AUTHOR]

The molecular mechanisms of selective RNA loading into exosomes and other extracellular vesicles are not yet completely understood. In order to show that a pool of RNA sequences binds both the amino acid arginine and lipid membranes, we constructed a bifunctional RNA 10Arg aptamer specific for arginine and lipid vesicles. The preference of RNA 10Arg for lipid rafts was visualized and confirmed using FRET microscopy in neuroblastoma cells. The selection‐amplification (SELEX) method using a doped (with the other three nucleotides) pool of RNA 10Arg sequences yielded several RNA 10Arg(D) sequences, and the affinities of these RNAs both to arginine and liposomes are improved in comparison to pre‐doped RNA. Generation of these bispecific aptamers supports the hypothesis that an RNA molecule can bind both to RNA‐binding proteins (RBPs) through arginine within the RBP‐binding site and to membrane lipid rafts, thus facilitating RNA loading into exosomes and other extracellular vesicles. [ABSTRACT FROM AUTHOR]

BeKm‐1 is a peptide toxin from scorpion venom that blocks the pore of the potassium channel hERG (Kv11.1) in the human heart. Although individual protein structures have been resolved, the structure of the complex between hERG and BeKm‐1 is unknown. Here, we used molecular dynamics and ensemble docking, guided by previous double‐mutant cycle analysis data, to obtain an in silico model of the hERG–BeKm‐1 complex. Adding to the previous mutagenesis study of BeKm‐1, our model uncovers the key role of residue Arg20, which forms three interactions (a salt bridge and hydrogen bonds) with the channel vestibule simultaneously. Replacement of this residue even by lysine weakens the interactions significantly. In accordance, the recombinantly produced BeKm‐1R20K mutant exhibited dramatically decreased activity on hERG. Our model may be useful for future drug design attempts. [ABSTRACT FROM AUTHOR]

Aging‐induced cognitive impairment is associated with a loss of metabolic homeostasis and plasticity. An emerging idea is that targeting key metabolites is sufficient to impact the function of other organisms. Therefore, more metabolism‐targeted therapeutic intervention is needed to improve cognitive impairment. We first conducted untargeted metabolomic analyses and 16S rRNA to identify the aging‐associated metabolic adaption and intestinal microbiome change. Untargeted metabolomic analyses of plasma revealed L‐arginine metabolic homeostasis was altered during the aging process. Impaired L‐arginine metabolic homeostasis was associated with low abundance of intestinal Akkermansia muciniphila (AKK) colonization in mice. Long‐term supplementation of AKK outer membranes protein‐Amuc_1100, rescued the L‐arginine level and restored cognitive impairment in aging mice. Mechanically, Amuc_1100 acted directly as a source of L‐arginine and enriched the L‐arginine‐producing bacteria. In aged brain, Amuc_1100 promoted the superoxide dismutase to alleviated oxidation stress, and increased nitric oxide, derivatives of L‐arginine, to improve synaptic plasticity. Meanwhile, L‐arginine repaired lipopolysaccharide‐induced intestinal barrier damage and promoted growth of colon organoid. Our findings indicated that aging‐related cognitive impairment was closely associated with the disorders of L‐arginine metabolism. AKK‐derived Amuc_1100, as a potential postbiotic, targeting the L‐arginine metabolism, might provide a promising therapeutic strategy to maintain the intestinal homeostasis and cognitive function in aging. [ABSTRACT FROM AUTHOR]

Secretory proteins of Plasmodium exhibit differential spatial and functional activity within the host cell nucleus. However, the nuclear localization signals (NLSs) for these proteins remain largely uncharacterized. In this study, we have identified and characterized two NLSs in the circumsporozoite protein of Plasmodium falciparum (Pf‐CSP). Both NLSs in the Pf‐CSP contain clusters of lysine and arginine residues essential for specific interactions with the conserved tryptophan and asparagine residues of importin‐α, facilitating nuclear translocation of Pf‐CSP. While the two NLSs of Pf‐CSP function independently and are both crucial for nuclear localization, a single NLS of Pf‐CSP leads to weak nuclear localization. These findings shed light on the mechanism of nuclear penetrability of secretory proteins of Plasmodium proteins. [ABSTRACT FROM AUTHOR]

Ethanol has been widely used for the extraction of propolis. Due to its certain disadvantages, there has been an ongoing search to find alternative non‐ethanolic extraction solvents. This study aimed to compare the phenolics, antioxidant, and antibacterial activity of propolis extracts prepared with 70% ethanol (EWE), propylene glycol (PGE), and L‐arginine solution (BE). All extracts were subjected to an in vitro simulated digestion procedure, and the phenolic profile of non‐digested and digested samples was determined by using LC–MS/MS. Additionally, the change in total phenolic (TPC), total flavonoid content (TFC), and antioxidant capacities were determined at each digestion phase. TPC and TFC of non‐digested propolis extracts had similar values, although BE showed higher antioxidant capacity (p <.05). The amount of TPC reached or transformed at the intestinal stage was higher for BE and PG compared to EWE. BE also provided the highest antioxidant capacity assay in digested samples. The most common phenolics were pinocembrin, pinobanskin, galangin, and CAPE in non‐digested extracts. However, their concentration was drastically reduced by digestion, and their recovery (R%) ranged from 0% to 9.38% of the initial amount detected in the non‐digested extracts. Chrysin was the most bioaccessible flavonoid in all extracts. Among phenolic acids, the highest R% was determined for trans‐cinnamic acid (22.14%) from BE. All extracts showed in vitro inhibitory activity against Escherichia coli and Staphylococcus aureus. This study suggests that an L‐arginine solution could be used as an alternative solvent to ethanol and propylene glycol for propolis extraction. [ABSTRACT FROM AUTHOR]

Aim: We sought to investigate the release of neutrophil extracellular traps (NETs) in neutrophils from individuals with rheumatoid arthritis (RA) and controls and compare the presence of NETs in gingival tissues according to periodontal status. Also, the association between single nucleotide polymorphisms (SNPs) of the peptidyl arginine deaminase type 4 (PADI4) gene and the GTG haplotype with RA, periodontitis and NETs was evaluated in vitro. Materials and Methods: Peripheral neutrophils were isolated by density gradient, and NET concentration was determined by the PicoGreen method. Immunofluorescence was studied to identify NETs by co‐localization of myeloperoxidase (MPO)‐citrullinated histone H3 (H3Cit). Genotyping for SNPs (PADI4_89; PADI4_90; PADI4_92; and PADI4_104) was performed in 87 individuals with RA and 111 controls. Results: The release of NETs in vitro was significantly higher in individuals with RA and periodontitis and when stimulated with Porphyromonas gingivalis. Gingival tissues from subjects with RA and periodontitis revealed increased numbers of MPO‐H3Cit‐positive cells. Individuals with the GTG haplotype showed a higher release of NETs in vitro and worse periodontal parameters. Conclusions: The release of NETs by circulating neutrophils is associated with RA and periodontitis and is influenced by the presence of the GTG haplotype. [ABSTRACT FROM AUTHOR]

Background: Oral care regimens can be explored to improve oral health in patients with gingivitis. This study aimed to evaluate the efficacy of a multicomponent oral care regimen with a dual zinc plus arginine (DZA) toothpaste and cetylpyridinium chloride with zinc lactate (CPC + Zn) mouthwash in reducing gingival bleeding in patients with gingivitis. Methods: This randomized clinical trial included 94 participants with gingivitis who were randomized into two groups: the DZA/CPC + Zn group, which used a 1450‐ppm fluoride toothpaste containing 0.96% zinc plus 1.5% arginine and a fluoride‐containing mouthwash with 0.075% CPC and 0.28% zinc lactate, and the control group, which used a 1450‐ppm fluoride toothpaste and a placebo mouthwash for 6 months. All participants were examined by a blinded examiner who measured the gingival index, plaque index, and gingival severity index. Data were analyzed using paired t test, independent t test, and analysis of covariance (ANCOVA). Results: Both groups presented statistically significant reductions in all clinical parameters compared to baseline. The DZA/CPC + Zn group exhibited significantly greater reductions in gingival index, gingival severity index, proximal gingival index, plaque index and proximal plaque index compared to the control group at 1, 3, and 6 months. Furthermore, DZA/CPC + Zn significantly decreased the percentage of patients with generalized gingivitis over a 6‐month follow‐up period. However, differences between the DZA/CPC + Zn and the control groups were not maintained after both groups established similar regimens with fluoride toothpaste. Conclusion: The multicomponent oral care regimen consisting of DZA toothpaste and CPC + Zn mouthwash is effective in reducing gingival inflammation and supragingival biofilm in patients with gingivitis. [ABSTRACT FROM AUTHOR]

The rationale for replacing the old binary of structure–function with the trinity of structure, disorder, and function has gained considerable ground in recent years. A continuum model based on the expanded form of the existing paradigm can now subsume importance of both conformational flexibility and intrinsic disorder in protein function. The disorder is actually critical for understanding the protein–protein interactions in many regulatory processes, formation of membrane‐less organelles, and our revised notions of specificity as amply illustrated by moonlighting proteins. While its importance in formation of amyloids and function of prions is often discussed, the roles of intrinsic disorder in infectious diseases and protein function under extreme conditions are also becoming clear. This review is an attempt to discuss how our current understanding of protein function, specificity, and evolution fit better with the continuum model. This integration of structure and disorder under a single model may bring greater clarity in our continuing quest for understanding proteins and molecular mechanisms of their functionality. [ABSTRACT FROM AUTHOR]

Atherosclerosis is initiated with endothelial cell (EC) dysfunction and vascular inflammation under hyperlipidemia. Sirtuin 3 (SIRT3) is a mitochondrial deacetylase. However, the specific role of endothelial SIRT3 during atherosclerosis remains poorly understood. The present study aims to study the role and mechanism of SIRT3 in EC function during atherosclerosis. Wild‐type Sirt3f/f mice and endothelium‐selective SIRT3 knockout Sirt3f/f; Cdh5Cre/+ (Sirt3EC‐KO) mice are injected with adeno‐associated virus (AAV) to overexpress PCSK9 and fed with high‐cholesterol diet (HCD) for 12 weeks to induce atherosclerosis. Sirt3EC‐KO mice exhibit increased atherosclerotic plaque formation, along with elevated macrophage infiltration, vascular inflammation, and reduced circulating L‐arginine levels. In human ECs, SIRT3 inhibition resulted in heightened vascular inflammation, reduced nitric oxide (NO) production, increased reactive oxygen species (ROS), and diminished L‐arginine levels. Silencing of SIRT3 results in hyperacetylation and deactivation of Argininosuccinate Synthase 1 (ASS1), a rate‐limiting enzyme involved in L‐arginine biosynthesis, and this effect is abolished in mutant ASS1. Furthermore, L‐arginine supplementation attenuates enhanced plaque formation and vascular inflammation in Sirt3EC‐KO mice. This study provides compelling evidence supporting the protective role of endothelial SIRT3 in atherosclerosis and also suggests a critical role of SIRT3‐induced deacetylation of ASS1 by ECs for arginine synthesis. [ABSTRACT FROM AUTHOR]

Objectives: Cigarette consumption is common around the world and besides its negative effects on health, and its effects on periodontitis draw attention. Arginine metabolites are involved in the pathogenesis of several systemic inflammatory diseases' including cardiovascular diseases. Our aim was to determine periodontitis and healthy individuals' arginine metabolites and IL‐6 levels in saliva and serum and to evaluate those according to smoking status. Materials and Methods: The study consisted of four groups: healthy individuals (control [C]; n = 20), smokers with healthy periodontium (S‐C; n = 20), nonsmokers with Stage‐III Grade‐B generalized periodontitis (P; n = 20) and smokers with Stage‐III Grade‐C generalized periodontitis (S‐P; n = 18). Periodontal parameters were measured. Analysis of methylated arginine metabolites was performed by LC–MS/MS, and IL‐6 levels were determined by ELISA kits. Results: In nonsmokers, salivary concentrations of asymmetric dimethylarginine (ADMA) and symmetrical dimethylarginine (SDMA) were higher in the periodontitis than control (p < 0.001, p = 0.010). Smokers with periodontitis exhibited higher ADMA (p = 0.033, p < 0.001) and arginine (p = 0.030, p = 0.001) saliva concentrations than smoking and nonsmoking controls. Conclusions: Our results demonstrated that salivary concentrations of ADMA and SDMA were associated with periodontitis. Smoking increased ADMA, SDMA and NG‐monomethyl L‐arginine (L‐NMMA) levels in serum only in periodontitis patients. [ABSTRACT FROM AUTHOR]

Microwave heating was applied to isomerize maltose to maltulose, using arginine as a catalyst. The initial molar ratio of arginine/maltose was kept constant at 0.05. Maltulose yields of 0.28–0.30 were achieved within 90–400 s, dependent on the microwave power and the volume of the substrate solution but not on the initial concentration of maltose, indicating that isomerization of maltose by microwave heating is highly productive. Independent of the power of the microwave oven and the volume of the substrate solution, the fraction of remaining maltose, the yield of maltulose, the pH of the reaction mixture, and its absorbance at 280 and 420 nm could be expressed as a function of energy density, which was defined as the amount of energy absorbed per unit volume of the reaction mixture. This indicates that the operating conditions for the isomerization of maltose to maltulose by microwave heating can be determined based on the energy density. Practical applications: Isomerization of aldose saccharides to their rare keto‐isomers in the presence of arginine in a heated aqueous solution is a green and effective process. To further improve the process efficiency, microwave heating can be employed. This study also demonstrated that a so‐called "energy density" can be used to determine the operating condition for the isomerization of sugar by microwave heating. [ABSTRACT FROM AUTHOR]

Extracellular domain (ECD) antigens are crucial components for antibody discovery, in vitro assays, and epitope mapping during therapeutical antibody development. Oftentimes, those antigens are difficult to produce while retaining the biologic function/activity upon extracellular secretion in commonly used expression systems. We have developed an effective method to cope with the challenge of generating quality antigen ECDs. In this method, a monoclonal antibody (Mab) or antibody fragment antigen‐binding (Fab) region acts as a "chaperone" to stabilize the antigen ECD through forming an antibody:antigen complex. This methodology includes transient co‐expression of the complex in Chinese hamster ovary cells and then dissociation of the purified complex into individual components by low pH treatment in the presence of arginine. The antigen is then separated from the chaperone on a preparative size exclusion chromatography (pSEC) followed by an optional affinity chromatography process to remove residual Mab or Fab. We demonstrate this co‐expression/disassociation methodology on two difficult‐to‐express antigen ECDs from cluster‐of‐differentiation/cytokine family and were successful in producing stable, biologically active antigens when the common methods using Histidine‐tagged and/or Fc‐fused protein failed. This can be applied as a general approach for antigen production if a Mab or binding partner is available. [ABSTRACT FROM AUTHOR]

The MT‐TL2 m.12315G>A pathogenic variant has previously been reported in five individuals with mild clinical phenotypes. Herein we report the case of a 5‐year‐old child with heteroplasmy for this variant who developed neurological regression and stroke‐like episodes similar to those observed in mitochondrial encephalopathy, lactic acidosis, and stroke‐like episodes (MELAS). Biochemical evaluation revealed depletion of arginine on plasma amino acid analysis and low z‐scores for citrulline on untargeted plasma metabolomics analysis. These findings suggested that decreased availability of nitric oxide may have contributed to the stroke‐like episodes. The use of intravenous arginine during stroke‐like episodes and daily enteral L‐citrulline supplementation normalized her biochemical values of arginine and citrulline. Untargeted plasma metabolomics showed the absence of nicotinamide and 1‐methylnicotinamide, and plasma total glutathione levels were low; thus, nicotinamide riboside and N‐acetylcysteine therapies were initiated. This report expands the phenotype associated with the rare mitochondrial variant MT‐TL2 m.12315G>A to include neurological regression and a MELAS‐like phenotype. Individuals with this variant should undergo in‐depth biochemical analysis to include untargeted plasma metabolomics, plasma amino acids, and glutathione levels to help guide a targeted approach to treatment. [ABSTRACT FROM AUTHOR]

HLA‐C*02 246 has one nucleotide change from HLA‐C*02:02:02:01 at nucleotide 523 changing Arginine to Cysteine at residue 151. [ABSTRACT FROM AUTHOR]

Three‐spot seahorse (Hippocampus trimaculatus) has been consumed as traditional Chinese medicine in Asian society. This study was designed to analyze the bioactive compounds of the solvent extracts from cultured three‐spot seahorse by high pressure liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC‐ESI/MS/MS). Subsequently, their biological activities were evaluated and confirmed by cell modes and Western blot analysis. Experimental results indicated that taurine and arginine were the primary bioactive compounds identified and quantified without pre‐ or post‐column derivatization within 20 min retention time. The analytical method was established and validated with intraday/interday RSD from 0.25% to 3.34% and with recovery from 87.8% to 91.2%. As compared to other extracts, water layer extract (WLE) contained the most taurine and arginine contents of 6.807 and 0.437 mg/g (dry basis), respectively. In the meanwhile, WLE also showed anti‐inflammatory activity on LPS‐induced NO production and inhibited the protein expression of TNF‐α and COX‐2 by Western blot analysis with better cell viability. [ABSTRACT FROM AUTHOR]

Background: Evidence on the efficacy of calcium sodium phosphosilicate (CSPS) and arginine dentifrices on reducing root sensitivity (RS) following non‐surgical periodontal therapy (NSPT) is limited. The aim of this study was to compare the efficacy of these dentifrices in reducing RS during daily activities in patients undergoing NSPT. Methods: Using a double‐blind randomized controlled trial, CSPS, arginine, or control dentifrices were randomly assigned to 45 RS individuals following NSPT. The participants used the dentifrices 2×/day for 8 weeks. A self‐reported visual analog scale (VAS) was assessed during daily activities. Results: Self‐reported VAS scores were similar among the three groups at each time point. The with‐in group analysis revealed that the arginine dentifrice reduced RS from Week 1–8 compared with baseline in response to cold. Similarly, the CSPS dentifrice reduced RS at Week 4 and 8. The CSPS and arginine dentifrices exhibited RS relief resulting from toothbrushing starting at Week 4 and 2, respectively. In response to air, RS relief was observed from Week 4 in the arginine group. The number of patients with VAS > 2 in response to cold declined at Week 2 and 4 in the CSPS and arginine groups, respectively. In response to toothbrushing, only 10% in the test groups still had RS at Week 8. In response to air, the number of RS patients only in the arginine group decreased at Week 4. Conclusion: The CSPS and arginine dentifrices provided comparable RS relief during daily activities within 2–4 weeks and remained effective up to 8 weeks. [ABSTRACT FROM AUTHOR]

BACKGROUND: The pinewood nematode (Bursaphelenchus xylophilus) causes severe damage to pine trees. The nematophagous fungus, Esteya vermicola, exhibits considerable promise in the biological control of Bursaphelenchus xylophilus due to its infectivity. Notably, the lunate conidia produced by E. vermicola can infect Bursaphelenchus xylophilus. In the study, we aim to investigate the genes involved in the formation of the lunate conidia of E. vermicola CBS115803. RESULTS: Esteya vermicola CBS115803 yielded 95% lunate conidia on the complete medium (CM) and 86% bacilloid conidia on the minimal medium (MM). Transcriptomic analysis of conidia from both media revealed a significant enrichment of differentially expressed genes in the pathway related to 'cellular amino acid biosynthesis and metabolism'. Functional assessment showed that the knockout of two arginine biosynthesis genes (EV232 and EV289) resulted in defects in conidia germination, mycelial growth, lunate conidia formation, and virulence of E. vermicola CBS115803 in Bursaphelenchus xylophilus. Remarkably, the addition of arginine to the MM improved mycelial growth, conidiation and lunate conidia formation in the mutants and notably increased conidia yield and the lunate conidia ratio in the wild‐type E. vermicola CBS115803. CONCLUSION: This investigation confirms the essential role of two arginine biosynthesis genes in lunate conidia formation in E. vermicola CBS115803. The findings also suggest that the supplementation of arginine to the culture medium can enhance the lunate conidia yield. These insights contribute significantly to the application of E. vermicola CBS115803 in managing Bursaphelenchus xylophilus infections. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Aqueous solutions containing alkaline salts of natural amino acids, such as those from protein in plant seeds or high protein animal‐based waste, are green CO2‐separation solvents. In the present work, potassium salts of nine such amino acids were chosen for an in‐depth study: alanine, arginine, aspartic acid, glutamic acid, glycine, leucine, proline, serine, and valine. The kinetics of CO2 absorption in aqueous solutions of these salts was studied using a stirred cell. From the measurements of the absorption rate at different salt concentrations (molarity 0.1 and higher), CO2 partial pressures (5–25 kPa), and temperatures (298–308 K), values of the reaction order, rate constant, and activation energy were determined. Additionally, the liquid‐side mass transfer coefficient (0.005 cm/s) was also found. Potassium salts of proline, glycine, and arginine were most reactive and, hence, were chosen for equilibrium study. The loading capacity of these salts was measured at 308 K in a vapour–liquid equilibrium setup at near‐ambient pressure. On the contrary, the other chosen acids were comparatively less reactive with CO2. [ABSTRACT FROM AUTHOR]

Conventional treatment methods are not effective enough to fight the rapid increase in cancer cases. The interest is increasing in the investigation of herbal sources for the development of new anticancer therapeutics. This study aims to investigate the antitumor capacity of Hypericum alpestre (H. alpestre) extract in vitro and in vivo, either alone or in combination with the inhibitors of the l‐arginine/polyamine/nitric oxide (NO) pathway, and to characterize its active phytochemicals using advanced chromatographic techniques. Our previous reports suggest beneficial effects of the arginase inhibitor NG‐hydroxy‐nor‐ l‐arginine and NO inhibitor NG‐nitro‐Larginine methyl ester in the treatment of breast cancer via downregulation of polyamine and NO synthesis. Here, the antitumor properties of H. alpestre and its combinations were explored in vivo, in a rat model of mammary gland carcinogenesis induced by subcutaneous injection of 7,12‐dimethylbenz[a]anthracene. The study revealed strong antiradical activity of H. alpestre aerial part extract in chemical (DPPH/ABTS) tests. In the in vitro antioxidant activity test, the H. alpestre extract demonstrated pro‐oxidant characteristics in human colorectal (HT29) cells, which were contingent upon the hemostatic condition of the cells. The H. alpestre extract expressed a cytotoxic effect on HT29 and breast cancer (MCF‐7) cells measured by the MTT test. According to comet assay results, H. alpestre extract did not exhibit genotoxic activity nor possessed antigenotoxic properties in HT29 cells. Overall, 233 substances have been identified and annotated in H. alpestre extract using the LC‐Q‐Orbitrap HRMS system. In vivo experiments using rat breast cancer models revealed that the H. alpestre extract activated the antioxidant enzymes in the liver, brain, and tumors. H. alpestre combined with chemotherapeutic agents attenuated cancer‐like histological alterations and showed significant reductions in tumor blood vessel area. Thus, either alone or in combination with Nω‐OH‐nor‐ l‐arginine and Nω‐nitro‐ l‐arginine methyl ester, H. alpestre extract exhibits pro‐ and antioxidant, antiangiogenic, and cytotoxic effects. Significance Statement: Our HPLC/MS/MS data shows that Hypericum alpestre (HA) contains a variety and abundance of natural antioxidants. H. alpestre possessed a remarkable cytotoxic effect on HT29 and MCF‐7 cancer cell cultures and acted as a pro‐oxidant in cellular models. The combination of H. alpestre extract with inhibitors of the l‐arginine metabolic pathway presents synergistic Anticancer effects against the induced mammary tumor. The H. alpestre extract alone or combined with l‐arginine metabolic regulatory compounds, demonstrates significant potential for the development of novel therapeutic models. [ABSTRACT FROM AUTHOR]

Some chemotherapeutic drugs can induce cancer cell death and enhance antitumor T‐cell immunity in cancer‐bearing hosts. Immunomodulatory reagents could augment such chemotherapy‐induced effects. We previously reported that oral digestion of Lentinula edodes mycelia (L.E.M.) extract or l‐arginine supplementation can augment antitumor T‐cell responses in cancer‐bearing mice. In this study, the effects of L.E.M. extract with or without l‐arginine on the therapeutic efficacy of immunogenic chemotherapy by 5‐fluorouracil (5‐FU)/oxaliplatin (L‐OHP) and/or cyclophosphamide (CP) are examined using two mouse colon cancer models. In MC38 and CT26 cancer models, therapy with 5‐FU/L‐OHP/CP significantly suppressed tumor growth, and supplementation with L.E.M. extract halved the tumor volumes. However, the modulatory effect of L.E.M. extract was not significant. In the CT26 cancer model, supplementation with L.E.M. extract and l‐arginine had no clear effect on tumor growth. In contrast, their addition to chemotherapy halved the tumor volumes, although the effect was not significant. There was no difference in the cytotoxicity of tumor‐specific cytotoxic T cells generated from CT26‐cured mice treated by chemotherapy alone versus chemotherapy combined with L.E.M. extract/ l‐arginine. These results indicate that the antitumor effects of immunogenic chemotherapy were too strong to ascertain the effects of supplementation of L.E.M. extract and l‐arginine, but these reagents nonetheless have immunomodulatory effects on the therapeutic efficacy of immunogenic chemotherapy in colon cancer‐bearing mice. [ABSTRACT FROM AUTHOR]

The continuous spread of resistance genes among bacterial populations, in particular in hospital setting, threatens the advances of our medical systems and already costs more than 1 million lives per year. Antimicrobial polymers (APs) are a promising type of materials to counteract these developments, as they are non‐susceptible toward resistance development, and even target resistant bacteria. We herein show the synthesis of an arginine‐containing monomer and its polymerization via photo‐induced reversible addition‐fragmentation chain‐transfer polymerization. The synthesis is straightforward, and the macromolecules possess two charged functions (i.e., guanidinium and ammonium) per repeating unit after deprotection. Assessment of the biological activity reveals that polymers inhibit the growth of methicillin‐resistant Staphylococcus aureus (MRSA) while being relatively inactive against tested Gram‐negative strains. Surprisingly, among the tested polymers, the homopolymer of the arginine‐derived monomer is the best‐performing material, even though it possesses no notable hydrophobic units. Toxicity tests against red blood cells and other mammalian cells show a good biocompatibility of polymers, leading to an overall excellent selectivity. Using membrane models, the mechanism of action was found to be membrane disruption. The good selectivity of the herein presented polymer for MRSA makes them promising materials for the development of therapeutic agents against such infections. [ABSTRACT FROM AUTHOR]

Protein arginine methyltransferase (PRMT) plays essential roles in tumor initiation and progression, but its underlying mechanisms in the treatment sensitivity of endometrial cancer (EC) remain unclear and warrant further investigation. Here, a comprehensive analysis of the Cancer Genome Atlas database and Clinical Proteomic Tumor Analysis Consortium database identifies that PRMT3 plays an important role in EC. Specifically, further experiments show that PRMT3 inhibition enhances the susceptibility of EC cells to ferroptosis. Mechanistically, PRMT3 interacts with Methyltransferase 14 (METTL14) and is involved in its arginine methylation. In addition, PRMT3 inhibition‐mediated METTL14 overexpression promotes methylation modification via an m6A‐YTHDF2‐dependent mechanism, reducing Glutathione peroxidase 4 (GPX4) mRNA stability, increasing lipid peroxidation levels, and accelerating ferroptosis. Notably, combined PRMT3 blockade and anti‐PD‐1 therapy display more potent antitumor effects by accelerating ferroptosis in cell‐derived xenograft models. The specific PRMT3 inhibitor SGC707 exerts the same immunotherapeutic sensitizing effect in a patient‐derived xenograft model. Notably, blocking PRMT3 improves tumor suppression in response to cisplatin and radiation therapy. Altogether, this work demonstrates that PRMT3 depletion is a promising target for EC. [ABSTRACT FROM AUTHOR]

Bio‐inspired design of peptides represents one facile strategy for development of supramolecular monomers for self‐assembly into well‐defined nanostructures. Inspired by methylation of arginine during post‐translational modification for manipulating protein functions, herein, the controllable self‐assembly of peptides via rational incorporation of methylated arginine residues into bola‐amphiphilic peptides is reported. A series of bola‐amphiphilic peptides are designed and synthesized either containing natural arginine or methylated arginine and investigate the influence of arginine methylation on peptide assembly. This study finds that incorporation of symmetrically di‐methylated arginine into oppositely charged hexapeptide hex‐SDMAE leads to distinct assembling performance compare to natural peptide hex‐RE. The findings demonstrate that the methylation of rationally designed peptide sequences allows for regulation of self‐assembly of peptides, thus implying the great potential of arginine methylation in establishing controllable peptide assembling systems and creating in situ formulation of biomedical materials in the future. [ABSTRACT FROM AUTHOR]

An efficient, one pot, multicomponent, L‐arginine catalyzed synthesis of thiazolo[3,2‐a]pyrimidines is described. L‐arginine is an easily available, biodegradable, inexpensive, promising bio‐organic molecule. The current strategy is the first example of amino acid promoted, green synthesis of a series of thiazolo[3,2‐a]pyrimidines via the formation of CN and CC bonds. The major advantages of the present methodology such as recyclability of catalyst, operational simplicity, easy scale‐up, wide substrate scope, easy work‐up, inexpensive, excellent yields, and high atom economy make it a distinct improvement over the prevailing strategies. [ABSTRACT FROM AUTHOR]

Cu(II) complexes of positively charged amino acids L–Lysine and L‐Arginine appended to an anthracene unit and phenanthroline bases, namely [Cu(Anth‐Lys)(L)(ClO4)] (1, 2) and [Cu(Anth‐Arg)(L)(ClO4)] (3, 4) where L is 1,10‐phenanthroline (phen, 1 and 3), dipyrido[3,2‐a : 2′,3′‐c]phenazine (dppz, 2 and 4) were synthesized and fully characterized by various spectral and analytical methods. Cu(II) centered broad and weak d‐d band in the visible region along with phenanthroline based π→π* and n→π* bands in the UV region were observed in the electronic spectra of the complexes recorded in DMF‐Tris‐HCl buffer (1 : 4 v/v) (pH 7.2). The complexes 1–4 show efficient DNA binding propensity. They also demonstrated strong binding affinity for human serum albumin (HSA). The complexes showed efficient visible light‐induced cytotoxicity against A549 (human lung carcinoma), HaCaT (human epidermal keratinocytes) and MDA‐MB‐231(human breast cancer cells) cells with low dark toxicity. They generate both singlet oxygen (1O2) and hydroxyl radical (⋅OH) as reactive oxygen species (ROS) upon excitation with visible light which is believed to be responsible for killing cancer cells. Significant changes in the nuclear morphology of the HaCaT cells were observed when treated with complexes 2 and 4 in visible light compared to the non‐irradiated cells. [ABSTRACT FROM AUTHOR]

Summary: This study focused on the individual effects of l‐arginine and l‐lysine on the physicochemical properties of pale, soft and exudative (PSE)‐like chicken batter and sausages. The two amino acids decreased the cooking loss from 7.13 to 1.79 and 2.36%, respectively. They increased the hardness from 24.31 to 47.27 and 41.64 N, cohesiveness from 0.60 to 0.69 and 0.69, and chewiness from 12.15 to 28.30 and 22.80 N of PSE‐like sausage with a dense and uniform microstructure, respectively. Moreover, the two amino acids decreased the total expressible liquid and expressible fat, increased viscosity, and increased the storage and loss modulus of PSE‐like meat batters with smaller oil droplets. Differential scanning calorimetry revealed that the two amino acids increased Tmax1 and Tmax2. In summary, l‐arginine and l‐lysine improved the quality attributes of PSE‐like sausages by improving the emulsifying and gelling properties of PSE‐like meat batters. [ABSTRACT FROM AUTHOR]

Physical activity and nutrition play important roles in preventing adverse health outcomes that accompany aging. It has been shown that high-intensity interval training (HIIT) combined with citrulline (CIT) supplementation can improve physical and functional capacities. The aim of this study was to evaluate serum metabolites following a 12-week HIIT combined or not with CIT in obese older adults, and to correlate the metabolic changes with clinico-biological parameters changes. Eighty-six obese older adults completed a 12-week HIIT program combined with a 10 g daily supplementation of either CIT or placebo (PLA) during a double-blinded randomized interventional trial. Only participants with blood samples at T0 (before the intervention) and/or T12 (after the intervention) were included in our sub-analysis (HIIT-PLA-T0: n = 44 and HIIT-PLA-T12: n = 28; HIIT-CIT-T0: n = 39 and HIIT-CIT-T12: n = 42). Serum samples were analyzed by different liquid or gas phase chromatography methods coupled to mass spectrometry. Among the identified metabolites, 44 changed significantly following the 12-week intervention (Time effect), and 10 of them were more affected when HIIT was combined with CIT (Time × Supp effect). Arginine increased significantly due to the 12-week intervention. Correlation analyses demonstrated that decreased triglyceride (TG) (16:1/18:1/16:0) and aspartic acid significantly correlated with a reduction of adiposity-related parameters (fat mass, leg lean mass, leptin, total triglycerides and low-density lipoprotein). Arginine, TG (16:1/18:1/16:0) and aspartic acid might constitute biomarkers of cardiometabolic health and adiposity. Further studies are needed to confirm these associations and understand the underlying mechanisms. Highlights A 12-week intervention involving high-intensity interval training (HIIT) with or without citrulline (CIT) supplementation induced adaptations in the serum metabolome of obese older adults through significant changes in 44 metabolites. Changes in 23 metabolites were observed when a CIT supplementation was administered along with a 12-week HIIT intervention. TG (16:1/18:1/16:0) correlated with several adiposity parameters including leptin, triglycerides, legs lean mass. Aspartic acid correlated with several adiposity parameters including leptin, LDL cholesterol as well as android, arms and trunk fat mass. [ABSTRACT FROM AUTHOR]

Gastric ulcer is a common disease with increased prevalence in the aged population. Aged gastric mucosa has increased susceptibility to injury along with nonsteroidal anti‐inflammatory drugs use due to impaired mucosal defense and decreased vasodilator release. We investigated whether l‐arginine could protect against age‐related gastric ulceration induced by indomethacin. Aged and adult male Wistar rats were administered sole and combined treatment of l‐arginine and Nω‐nitro‐l‐arginine methyl ester (l‐NAME) before induction of gastric ulceration by indomethacin. The gastroprotective effect of l‐arginine was displayed only in adult rats with indomethacin‐induced gastric ulceration, as evidenced by a significant decrease in ulcer index, oxidative stress parameters, and mucosal myeloperoxidase activity along with increased mucosal PGE2 levels. Interestingly, the mucosal gene expressions of NF‐кB, iNOS, and COX‐2 were significantly suppressed by l‐arginine pretreatment and aggregated upon pretreatment with l‐NAME in both adult and aged rats treated with indomethacin. In conclusion, l‐arginine protected the rats' gastric mucosa against indomethacin‐induced gastric ulceration, possibly, at least in part, by enhancement of mucosal nitric oxide/PGE2 content along with suppressing gastric inflammation and oxidative stress. This study supposed that the gastroprotective effect of l‐arginine depends on aging, and even so, the adoption of a new approach to gastric ulcer treatment for the aged population is warranted. [ABSTRACT FROM AUTHOR]

Influenza A virus (IAV) relies on intricate and highly coordinated associations with host factors for efficient replication and transmission. Characterization of such factors holds great significance for development of anti‐IAV drugs. Our study identified protein arginine methyltransferase 5 (PRMT5) as a novel host factor indispensable for IAV replication. Silencing PRMT5 resulted in drastic repression of IAV replication. Our findings revealed that PRMT5 interacts with each protein component of viral ribonucleoproteins (vRNPs) and promotes arginine symmetric dimethylation of polymerase basic 2 (PB2). Overexpression of PRMT5 enhanced viral polymerase activity in a dose‐dependent manner, emphasizing its role in genome transcription and replication of IAV. Moreover, analysis of PB2 protein sequences across various subtypes of IAVs demonstrated the high conservation of potential RG motifs recognized by PRMT5. Overall, our study suggests that PRMT5 supports IAV replication by facilitating viral polymerase activity by interacting with PB2 and promoting its arginine symmetric dimethylation. This study deepens our understanding of how IAV manipulates host factors to facilitate its replication and highlights the great potential of PRMT5 to serve as an anti‐IAV therapeutic target. [ABSTRACT FROM AUTHOR]

Background: Current technologies for carbon dioxide (CO2) capture are based on a variety of physical and chemical processes using absorption towers. Overcoming the high energy consumption of conventional absorption is essential to develop a process that makes sense in terms of CO2 captured versus CO2 emitted. In this work, we propose the use of a membrane contactor that allows an efficient gas–liquid contact and an aqueous alkaline solution with several amino acids (i.e. arginine, methionine, valine, serine, 6‐aminohexanoic acid) as the absorption liquid. Results: Results show clear differences in absorption performance among the studied amino acids, with arginine as the best choice. Using arginine does not only lead to the highest mass transfer coefficient (ca 0.004 m3 m−2 min−1) in the membrane contactor but also a remarkable CO2 absorption capacity without the need for an alkaline component that enhances the reaction and the mass transfer. Conclusion: The use of membrane contactors with a green solvent is a promising step that needs further studies. As the results demonstrate, arginine has shown a great performance; thus, it has been chosen for further investigation. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Substrate‐binding proteins (SBPs) are used by organisms from the three domains of life for transport and signalling. SBPs are composed of two domains that collectively trap ligands with high affinity and selectivity. To explore the role of the domains and the integrity of the hinge region between them in the function and conformation of SBPs, here, we describe the ligand binding, conformational stability and folding kinetics of the Lysine Arginine Ornithine (LAO) binding protein from Salmonella thiphimurium and constructs corresponding to its two independent domains. LAO is a class II SBP formed by a continuous and a discontinuous domain. Contrary to the expected behaviour based on their connectivity, the discontinuous domain shows a stable native‐like structure that binds l‐arginine with moderate affinity, whereas the continuous domain is barely stable and shows no detectable ligand binding. Regarding folding kinetics, studies of the entire protein revealed the presence of at least two intermediates. While the unfolding and refolding of the continuous domain exhibited only a single intermediate and simpler and faster kinetics than LAO, the folding mechanism of the discontinuous domain was complex and involved multiple intermediates. These findings suggest that in the complete protein the continuous domain nucleates folding and that its presence funnels the folding of the discontinuous domain avoiding nonproductive interactions. The strong dependence of the function, stability and folding pathway of the lobes on their covalent association is most likely the result of the coevolution of both domains as a single unit. [ABSTRACT FROM AUTHOR]

There is a growing global interest in using peptides in the health industry for pharmaceuticals, cosmetics, and natural food products. Peptides contain two or more linked amino acids, whereas more than 50 amino acids are classified as polypeptides. Although there is a growing level of interest in the use of peptides in the health and wellness industry, there is a lack of literature pertaining to a specific tripeptide derived from arginine, alanine, and lysine (RAK) that is of interest for human dietary use. Therefore, a 90‐day repeated‐dose toxicity study was performed in rats to evaluate the subchronic oral toxicity of RAK. Eighty Han:WIST rats were administered RAK by gavage at doses of 0, 250, 500, or 1000 mg/kg bw/day. There were no mortalities or other treatment related effects, and no target organs were identified. A no‐observed‐adverse‐effect‐level (NOAEL) of 1000 mg/kg bw/day, the highest dose tested, was determined. This study will contribute to the body of research in regard to the safety of the use of RAK. There is a growing global interest in using peptides in the natural health industry; however, there is a lack of literature pertaining to a specific tripeptide, derived from arginine, alanine, and lysine (RAK). Therefore, a 90‐day repeated‐dose toxicity study was performed to evaluate the safety of RAK. A no‐observed‐adverse‐effect level in Han:WIST rats was 1000 mg/kg bw/day, the highest dose tested. [ABSTRACT FROM AUTHOR]

Fetal development and parturition are precisely regulated processes that involve continuous crosstalk between the mother and the fetus. Our previous discovery that wild‐type mice carrying steroid receptor coactivator (Src)‐1 and Src‐2 double‐deficient fetuses exhibit impaired lung development and delayed labor, which indicates that the signals for parturition emanate from the fetus. In this study, we perform RNA sequencing and targeted metabolomics analyses of the lungs from fetal Src‐1/‐2 double‐knockout mice and find that expression of arginase 1 (Arg1) is significantly decreased, accompanied by increased levels of the Arg1 substrate L‐arginine. Knockdown of Arg1 in the lungs of fetal mice induces apoptosis of epithelial cells and dramatically delays initiation of labor. Moreover, treatment of human myometrial smooth muscle cells with L‐arginine significantly inhibits spontaneous contractions by attenuating activation of NF‐κB and downregulating expression of contraction‐associated protein genes. Transcription factors GR and C/EBPβ increase transcription of Arg1 in an Src‐1/Src‐2‐dependent manner. These findings provide new evidence that fetus‐derived factors may play dual roles in coordinating fetal lung development and the initiation of labor. Synopsis: Fetal lung arginase 1 (Arg1) and L‐arginine are involved in the coordination of fetal lung development and the initiation of labor in mice. Arg1 is upregulated in the lungs of fetal mice during gestation.Transactivation of the Arg1 promoter is enhanced by GR and C/EBPβ in an Src‐1/‐2‐dependent manner.Arg1 knockdown in fetal lungs causes L‐arginine accumulation, which induces apoptosis of alveolar epithelial cells and affects fetal lung development.Arg1 inhibition in fetal lungs delays labor of pregnant mice, due to the de‐activation of NF‐κB signaling pathway and the attenuation of myometrial cell contractility caused by L‐arginine accumulation. [ABSTRACT FROM AUTHOR]

Mephedrone is a representative of synthetic cathinones that is known from its rewarding and psychostimulant effects. It exerts behavioural sensitization after repeated and then interrupted administration. In our study, we investigated a role of the L‐arginine‐NO‐cGMP‐dependent signalling in the expression of sensitization to hyperlocomotion evoked by mephedrone. The study was carried out in male albino Swiss mice. The tested mice received mephedrone (2.5 mg/kg) for 5 consecutive days and on the 20th day of the experiment (the 'challenge' day) animals received both mephedrone (2.5 mg/kg) and a given substance that affects the L‐arginine‐NO‐cGMP signalling, that is, L‐arginine hydrochloride (125 or 250 mg/kg), 7‐nitroindazole (10 or 20 mg/kg), L‐NAME (25 or 50 mg/kg) or methylene blue (5 or 10 mg/kg). We observed that 7‐nitroindazole, L‐NAME and methylene blue inhibited the expression of sensitization to the mephedrone‐induced hyperlocomotion. Moreover, we demonstrated that the mephedrone‐induced sensitization is accompanied by lowered levels of D1 receptors and NR2B subunits in the hippocampus, whereas a concurrent administration of L‐arginine hydrochloride, 7‐nitroindazole and L‐NAME with the mephedrone challenge dose reversed these effects. Methylene blue only reversed the mephedrone‐induced effects on hippocampal levels of the NR2B subunit. Our study confirms that the L‐arginine‐NO‐cGMP pathway contributes to mechanisms underlying the expression of sensitization to the mephedrone‐evoked hyperlocomotion. [ABSTRACT FROM AUTHOR]