Search Results (334)

Experimental and theoretical studies were applied to investigate the adsorption properties of testagen (KEDG) peptide on copper surfaces in sodium chloride solution and, implicitly, its inhibition efficiency (IE) on metal corrosion. The tetrapeptide synthesized from the amino acids lysine (Lys), glutamic acid (Glu), aspartic acid (Asp), and glycine (Gly), named as H-Lys-Glu-Asp-Gly-OH, achieved an inhibition efficiency of around 86% calculated from electrochemical measurements, making KEDG a promising new copper corrosion inhibitor. The experimental data were best fitted to the Freundlich adsorption isotherm. The standard free energy of adsorption ($\mathsf{\Delta }{\mathrm{G}}_{\mathrm{a}\mathrm{d}\mathrm{s}}^{\mathrm{o}}$) reached the value of −30.86 kJ mol⁻¹, which revealed a mixed action mechanism of tetrapeptide, namely, chemical and physical spontaneous adsorption. The copper surface characterization was performed using optical microscopy and SEM/EDS analysis. In the KEDG presence, post-corrosion, SEM images showed a network surface morphology including microdeposits with an acicular appearance, and EDS analysis highlighted an upper surface layer consisting of KEDG, sodium chloride, and copper corrosion compounds. The computational study based on DFT and Monte Carlo simulation confirmed the experimental results and concluded that the spontaneous adsorption equilibrium establishment was the consequence of the contribution of noncovalent (electrostatic, van der Waals) interactions and covalent bonds. Full article

Breast cancer (BC) is a neoplasm characterized by high heterogeneity and is influenced by intrinsic molecular subtypes and clinical stage, aspects that remain underexplored in the Colombian population. This study aimed to characterize metabolic alterations associated with subtypes and disease progression in a group of newly diagnosed, treatment-naive Colombian women using an untargeted metabolomics approach. To improve metabolite coverage, samples were analyzed using LC-QTOF-MS and GC-QTOF-MS, along with amino acid profiling. The Luminal B subtype exhibited elevated levels of long-chain acylcarnitines and higher free fatty acid concentrations than the other subtypes. It also presented elevated levels of carbohydrates and essential glycolytic intermediates, suggesting that this subtype may adopt a hybrid metabolic phenotype characterized by increased glycolytic flux as well as enhanced fatty acid catabolism. Tumor, Node, and Metastasis (TNM) staging analysis revealed progressive metabolic reprogramming of BC. In advanced stages, a sustained increase in phosphatidylcholines and a decrease in lysophosphatidylcholines were observed, reflecting lipid alterations associated with key roles in tumor progression. In early stages (I-II), plasma metabolites with high discriminatory power were identified, such as glutamic acid, ribose, and glycerol, which are associated with dysfunctions in energy and carbohydrate metabolism. These results highlight metabolomics as a promising tool for the early diagnosis, clinical follow-up, and molecular characterization of BC. Full article

The insect resistance expression of Bacillus thuringiensis (Bt) cotton (Gossypium hirsutum L.) is unstable due to temporal and spatial variations in the Bt protein content in different organs and growth stages. The aim of this study was to improve the Bt protein content in cotton flowers and investigate the underlying physiological mechanism using biochemical analytical methods. In this study, a split-plot design with three replications was used. The main plots included two Bt cotton cultivars (a conventional cultivar, Sikang1 (S1), and a hybrid cultivar, Sikang3 (S3)), while five soil nitrogen application levels (CK (control check): normal level; N1: 125% of the CK; N2: 150% of the CK; N3: 175% of the CK; N4: 200% of the CK) constituted the subplots. The Bt protein content and related nitrogen metabolism parameters were measured. We found that the Bt protein content increased and then decreased with increasing nitrogen rates. It reached its maximum at N3, with significant increases of 71.86% in 2021 and 39.36% in 2022 compared to the CK. Correlation analysis indicated that the Bt protein content was significantly positively related to the soluble protein and free amino acid contents, as well as the GPT (glutamic pyruvic transaminase), GOT (glutamic oxaloacetic transaminase), GS (glutamine synthetase) and GOGAT (glutamate synthetase) activities. On the other hand, negative correlations were found between the Bt protein content and protease and peptidase activities. In addition, stepwise regression and path analysis indicated that the increased Bt protein content was mainly due to the enhanced GS and GOGAT activities. In summary, appropriately increasing nitrogen fertilizer application is a practical way to increase flower Bt protein content and insecticidal efficacy of Bt cotton. These findings provide an actionable agronomic strategy for sustaining Bt expression during the critical flowering period. Full article

The effects of different levels of microbial transglutaminase (MTGase) at 0% (control), 0.25%, 0.50% and 1% on the physicochemical properties, volatile compounds and free amino acid composition of pastırma, a Turkish dry-cured meat product, were investigated. The MTGase treatment had no significant effect on the a_w, L* and b* values of pastırma. The thiobarbituric acid reactive substances value decreased as the MTGase level increased. The maximum cutting force was found to be higher in enzyme-treated pastırma groups compared with the control. Enzyme treatment increased the maximum stress–relaxation force, but no statistical difference was observed between the 0.50% and 1% enzyme treatments. No significant differences were observed between groups in the volatile compound profile. However, in the correlation analysis, the control group showed a close correlation with the 0.25% MTGase group. This was also the case for the 0.5% and 1% MTGase groups. In the samples, glutamic acid, arginine, alanine, cystine and valine were determined to be the dominant free amino acids, and glutamic acid showed a close correlation with valine; lysine with arginine; and cystine with serine. MTGase had no significant effect on the total free amino acid content. Full article

Background/Objectives: In the context of preclinical studies, we have hitherto showcased that a low-molecular-weight ruthenium(III) complex we named AziRu holds significant potential for further developments as an anticancer candidate drug. When appropriately converted into stable nanomaterials and delivered into tumor cells, AziRu exhibits superior antiproliferative activity, benefiting from a multimodal mechanism of action. The activation of regulated cell death (RCD) pathways (i.e., apoptosis and autophagy) has been proved in metastatic phenotypes, including triple-negative breast cancer (TNBC) cells. This study focuses on a bioengineered lipophilic derivative of AziRu, named PalmiPyRu, that we are currently developing as a potential anticancer drug in preclinical studies. When delivered in this way, AziRu confirms a multimodal mechanism of action in effectively blocking the growth and proliferation of TNBC phenotypes. Special focus is reserved for the activation of the ferroptotic pathway as a consequence of redox imbalance and interference with iron homeostasis, as well as the glutathione biosynthetic pathway. Methods: Human preclinical models of specific TNBC phenotypes and healthy cell cultures of different histological origin were selected. After in vitro treatments, cellular responses were carefully analyzed, and targeted biochemical and molecular biology experiments coupled to confocal microscopy allowed us to explore the antiproliferative effects of PalmiPyRu. Results: In this study, we unveil that PalmiPyRu can enter TNBC cells and interfere with both the iron homeostasis and the cystine-glutamate antiporter system Xc-, causing significant oxidative stress and the accumulation of lipid oxidation products. The increase in intracellular reactive free iron and depletion of glutathione engender a lethal condition, driving cancer cells toward the activation of ferroptosis. Conclusions: Overall, these outcomes allow us, for the first time, to couple the antiproliferative effect of a ruthenium-based candidate drug with the inhibition of the Xc- antiporter system and Fenton chemistry, thereby branding PalmiPyRu as an effective multimodal inducer of ferroptosis. Molecular mechanisms of action deserve further investigations, and new studies are underway to uncover how interference with Xc- controls cell fate, allowing us to explore the connection between iron metabolism regulation, oxidative stress and RCD pathways activation. Full article

Nitrogen (N) critically regulates wheat growth and grain quality, yet the molecular mechanisms underlying foliar nitrogen application remain unclear. This study evaluated the effects of foliar nitrogen application (12.25 kg ha⁻¹) on the growth, grain yield, and quality of spring wheat, as well as its molecular mechanisms. The results indicated that N was absorbed within 3 h post-application, with leaf nitrogen concentration peaking at 12 h. The N treatment increased whole-plant dry matter accumulation and grain protein content by 11.34% and 6.8%, respectively. Amino acid content peaked 24 h post-application, increasing by 25.3% compared to the control. RNA-sequencing analysis identified 4559 and 3455 differentially expressed genes at 3 h and 24 h after urea treatment, respectively, these DEGs being primarily involved in nitrogen metabolism, photosynthetic carbon fixation, amino acid biosynthesis, antioxidant systems, and nucleotide biosynthesis. Notably, the plastidic glutamine synthetase gene (GS2) is crucial in the initial phase of urea application (3 h post-treatment). The pronounced downregulation of GS2 initiates a reconfiguration of nitrogen assimilation pathways. This downregulation impedes glutamine synthesis, resulting in a transient accumulation of free ammonia. In response to ammonia toxicity, the leaves promptly activate the GDH (glutamate dehydrogenase) pathway to facilitate the temporary translocation of ammonium. This compensatory mechanism suggests that GS2 downregulation may be a key switch that redirects nitrogen metabolism from the GS/GOGAT cycle to the GDH bypass. Additionally, the upregulation of the purine and pyrimidine metabolic routes channels nitrogen resources towards nucleic acid synthesis, and thereby supporting growth. Amino acids are then transported to the seeds, culminating in enhanced seed protein content. This research elucidates the molecular mechanisms underlying the foliar response to urea application, offering significant insights for further investigation. Full article

Background/Objectives: Gestational diabetes mellitus (GDM) represents an increased metabolic risk in future life for both mother and child. We hypothesize free fatty acids (FFAs) and amino acids (AAs) disturbances in plasma during second trimester might be indicating high risk of persisting glucose intolerance (PGI). The aim of study was to determine plasma FFAs and AAs during pregnancy in women with normal pregnancy and GDM and also in post-GDM women with PGI after delivery and to find potential association of altered FFAs and AAs profile with adverse peripartal outcomes and PGI after GDM. Material and Methods: A total of 54 pregnant women were included in the study. Of those 34 participants had GDM. PGI was diagnosed by oGTT up to one year after delivery. Plasma FFAs were determined using GC-FID and plasma AAs levels were determined using CE-MS method. Results: Decreased levels of tetradecanoic acid and several AAs were found in GDM group during pregnancy. Oleic and docosahexaenoic acid correlated positively while almost all AAs negatively correlated with oGTT values in the pregnancy (all p < 0.05, Spearman). Logistic regression model (using AAs, FFAs and BMI) identified higher citrulline and glutamate levels and lower tetradecenoic acid and choline as the best predictors for postpartum PGI. Some differences in AA levels were detected in women with macrosomic babies. Conclusions: Data support a possible link between GDM development and PGI after delivery and selected metabolite levels. The predictive potential of plasma FFAs and AAs levels on a diabetes risk in future life requires further validation. Full article

Sixteen long-ripened, high-quality Cabrales cheeses from independent producers underwent a comprehensive biochemical and microbiological characterisation. Significant variations in total microbial counts and specific microbial groups were observed among the cheeses. A metataxonomic analysis identified 249 prokaryotic amplicon sequence variants (ASVs) and 99 eukaryotic ASVs, respectively, which were classified into 52 prokaryotic and 43 eukaryotic species. The predominant species included bacteria of the genera Tetragenococcus, Lactococcus (of which Lactococcus lactis was used as a starter), and Staphylococcus, followed by Brevibacterium and Corynebacterium species. The starter mould Penicillium roqueforti was highly abundant in all cheeses; Debaryomyces hansenii, Geotrichum candidum, and Kluyveromyces spp. constituted the subdominant fungal populations. Glutamic acid (≈20 mg g⁻¹) was the most abundant free amino acid in all samples, followed by lysine, leucine, and valine (≈10–13 mg g⁻¹). Moderate-to-high amounts of the biogenic amines tyramine and ornithine were detected. A large variation between cheeses of the main organic acids (lactic, acetic, or butyric) was detected. Differences between samples were also observed for the majority volatile compounds, which included organic acids, alcohols, esters, and ketones. Positive and negative correlations between bacterial and fungal species were detected, as well as between microbial populations and key biochemical markers. Among the latter, Tetragenococcus halophilus correlated positively with ethyl caprylate and hexanoic acid, and Loigolactobacillus rennini correlated positively with γ-aminobutyric acid. Conversely, Staphylococcus equorum showed a strong negative correlation with ethyl caprylate and capric acid. These microbial and biochemical insights enabled us to propose a microbiota-based starter culture comprising prokaryotic and eukaryotic components to enhance Cabrales cheese quality. Full article

Background: γ-Aminobutyric acid (GABA) is a non-proteinogenic amino acid with key roles in plant metabolism, stress responses, and fruit nutritional quality. In tomato (Solanum lycopersicum), GABA levels are dynamically regulated during fruit development but decline in the late ripening stages. Methods: To enhance GABA accumulation, we used CRISPR/Cas9 to edit the calmodulin-binding domain (CaMBD) of SlGAD2 and SlGAD3, which encode glutamate decarboxylases (GADs). The resulting truncated enzymes were expected to be constitutively active. We quantified GABA content in leaves and fruits and performed transcriptomic analysis on edited lines at the BR+7 fruit stage. Results: CaMBD truncation significantly increased GABA levels in both leaves and fruits. In gad2 sg1 lines, GABA levels increased by 3.5-fold in leaves and 3.2-fold in BR+10 fruits; in gad3 sg3 lines, increases of 2.8- and 2.5-fold were observed, respectively. RNA-seq analysis identified 1383 DEGs in gad2 #1−5 and 808 DEGs in gad3 #3−8, with 434 DEGs shared across both lines. These shared DEGs showed upregulation of GAD, GABA-T, and SSADH, and downregulation of stress-responsive transcription factors including WRKY46, ERF, and NAC. Notably, total free amino acid content and fruit morphology remained unchanged despite elevated GABA. Conclusions: CRISPR/Cas9-mediated editing of the CaMBD in SlGAD genes selectively enhances GABA biosynthesis in tomato without adverse effects on development or fruit quality. These lines offer a useful platform for GABA-centered metabolic engineering and provide insights into GABA’s role in transcriptional regulation during ripening. Full article

Metabolic syndrome (MetS), characterized by obesity, insulin resistance, and dyslipidemia, is a major risk factor for renal injury. Oxidative stress (OxS) plays a pivotal role in its progression; however, the underlying molecular mechanisms are not fully understood. In this study, we established a rat model of MetS using a high-fat diet combined with a single-dose streptozotocin injection in male Wistar rats. MetS rats exhibited systemic OxS, evidenced by elevated circulating levels of free oxygen radicals and decreased antioxidant defense capacity, as well as hypertension, renal lipid peroxidation, glomerular hyperfiltration, and renal tubular injury. Transcriptomic profiling of renal tissue revealed significant downregulation of six OxS-related genes: C-C motif chemokine ligand 5 (CCL5), glutamate-cysteine ligase catalytic subunit, glutathione peroxidase 6, recombination activating gene 2, NAD(P)H: quinone oxidoreductase 1, and selenoprotein P-1. Among these downregulated genes, CCL5 was further confirmed to be repressed at both mRNA and protein levels across intrarenal and systemic compartments. Given its documented functions in immune signaling and redox homeostasis, CCL5 downregulation may contribute to enhanced oxidative damage in MetS-associated renal injury. These findings highlight the role of redox gene dysregulation in the pathogenesis of MetS-related kidney disease and support the potential of CCL5 as a biomarker for oxidative renal injury. Full article

Glutamine is an essential biomolecule that plays a pivotal role in many diseases, such as cancer, where it can serve as fuel for rapid proliferation. Treatments for these diseases can be monitored and optimized through the detection of glutamine, though standard glutamine detection procedures are costly and require complex instrumentation. Cell-free protein synthesis (CFPS) has recently enabled a paper-based, colorimetric glutamine sensor that carries the potential to increase test accessibility while dramatically reducing consumer cost to enable at-home, rapid treatment monitoring. Test sensitivity remained limited by residual assay background, thus motivating this work where CFPS reactions traditionally formulated with glutamate salts were compared to systems using alternative salts, including aspartate, acetate, citrate, and sulfate, to reduce the background generation of glutamine. This led to the discovery of a novel aspartate-based CFPS system that boasts a high signal strength and indetectable background noise over 225 min. Acetate-, citrate-, and sulfate-based systems also yielded zero background glutamine detection but at a lower signal response compared to the aspartate-based system. These findings mark crucial advancements in producing a cost-effective, simple glutamine monitor while simultaneously showcasing the adaptability of CFPS’s open reaction environment for solving complex challenges in next-generation biosensor development. Full article

Hypnum cupressiforme Hedw. is a widely distributed moss species with significant bioactive potential, but the phytochemical composition and biological activity of this species are not well documented yet, particularly in Bulgaria. The current study aimed to investigate the amino acid composition, free sugars, sterol profile, total polyphenol content, antioxidant activity, DNA-protective effect, and the anti-inflammatory activity of ethanolic extracts of H. cupressiforme. Amino acid analysis revealed that proline (2.282 g/100 g), isoleucine (2.047 g/100 g), and glutamic acid (1.746 g/100 g) were the dominant constituents. The moss contained mannose (1.76 g/100 g) and fructose (1.43 g/100 g) as major free sugars and a diverse sterol profile containing stigmasterol (4.37 mg/g), β-sitosterol (4.29 mg/g), and campesterol (3.34 mg/g) as major phytosterols, which are known for their potential health benefits, such as cholesterol regulation and anti-inflammatory effects. The antioxidant activity of the extracts was determined by DPPH and ABTS assays and expressed moderate free radical scavenging ability (2.56 and 4.15 mM TE/g DW). Furthermore, the extracts also exhibited a potent DNA-protective effect against oxidative damage and anti-inflammatory activity. These findings contribute to the phytochemical knowledge of H. cupressiforme and suggest that Bulgarian specimens may be worth further investigation for pharmaceutical, nutraceutical, and cosmetic applications. Full article

With the increasing popularity of traditional Chinese sausages both domestically and internationally, the flavor characteristics of sausages have become an important topic in food science research. However, comparative studies on the flavor differences between different types of traditional Chinese sausages are still limited. This study aimed to systematically compare the flavor profiles of three representative types of traditional Chinese sausages (Cantonese, Five-Spice, and Mala sausages), with 20 samples randomly selected from one batch of 100 sausages per type produced in December 2024, using a combination of headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS), amino acid analysis, electronic sensory analysis, and sensory evaluation techniques. Sensory evaluation revealed that Mala sausage exhibited a strong and numbing flavor. Cantonese sausage was characterized by sweet and alcoholic notes, while Five-Spice sausage displayed a more subtle and gentle flavor profile. A total of 39 volatile compounds were identified, with 2-methyl-1-butanol, 2-butanone, and butanal being the most abundant across all samples. Orthogonal partial least squares discriminant analysis (OPLS-DA) further pinpointed (+)-limonene, (Z)-ocimene, α-terpinene, β-myrcene, β-pinene, γ-terpinene, 2-pentanol, 2-octanone, and 1-hexanal as the key differential compounds responsible for the distinct flavor characteristics of each sausage type. Additionally, the free amino acid content in Mala sausage was significantly higher than that in the others, with glutamic acid and proline playing pivotal roles in shaping the taste profiles. These findings provide valuable theoretical and technical insights for the identification and control of flavor in sausage production, offering a scientific basis for guiding consumer preferences in sausages’ selection. Full article

As one kind of renewable aromatic polymer, lignin is severely underused due to its chemical recalcitrance. Lignin can endure demethylation modification to improve its activation by releasing more active functional groups. However, the process suffers from expensive, corrosive, and toxic issues by employing halogen-containing reagents, which has become an obstacle to industrial applications. Herein, a series of dicarboxylic acid-based protic ionic liquids (DAPILs) systems composed of ethanolamine and dibasic organic acids (e.g., aspartic acid (Asp), glutamic acid (Glu), succinic acid (SA), and glutaric acid (GA)) with 1~2:1 stoichiometric ratio, have been finely designed for the demethylation of industrial lignin. With [EOA][GA] treatment, the polyphenol content in lignin was favorably increased beyond 1.58 times. The structural tailoring and variation were fully characterized by 2D HSQC and ¹H NMR. The analysis results indicated that, with the increase of phenolic hydroxyl content in lignin, the β-O-4′ bond was broken and the content of structural units (S, G) and the S/G ratio of lignin decreased accordingly. After the treatment, the used IL and tailored lignin can be recovered over 95%. This novel, halogen-free and environmentally friendly lignin-cutting strategy not only opens avenues for high-value utilization of lignin but also expands the field of application of dicarboxylic acid-based protic ionic liquids. Full article

Pulsed electric field (PEF), a novel non-thermal processing technology, shows great potential in meat processing by regulating macromolecule metabolism and food quality. This study examined the effects of PEF pretreatment at varying electric field strengths (1, 2, and 3 kV/cm) and durations (30, 60, and 90 s) on the color, texture, moisture distribution, free amino acids, and flavor compounds in air-dried duck meat. PEF pretreatment significantly increased brightness (p < 0.05), while PEF treatment (3 kV/cm, 30 s) improved the textural properties of air-dried duck meat, reducing chewiness and hardness by 65.44% and 59.97%, respectively. It promoted myofibril disruption and vacuolization, reducing water mobility and improving moisture retention. Enhanced endogenous enzyme activity under PEF facilitated protein degradation, boosting total free amino acid content, particularly umami and sweet amino acids (glutamic acid, alanine). PEF pretreatment also elevated key aroma compounds, such as hexanal, methyl caprate, and 4-methyl valerate, improving the flavor profile of air-dried duck meat. This study provides technical support for integrating PEF technology into traditional poultry processing. Full article