Search Results (158)

Chinese perch (Siniperca chuatsi), an economically important freshwater fish in China, faces ammonia nitrogen stress under high-density aquaculture. This study investigated chronic ammonia nitrogen exposure effects on juvenile fish (95 ± 5 g) to establish safe concentration. Acute toxicity tests revealed a 96 h-LC₅₀ of 12.91 mg/L ammonia nitrogen, with a safe concentration of 1.29 mg/L ammonia nitrogen (non-ionic ammonia: 0.097 mg/L). In 28-day chronic experiments with ammonia nitrogen levels at 0, 0.61, 1.29, and 2.58 mg/L, ammonia nitrogen induced hepatic oxidative stress, with total superoxide dismutase, catalase, and glutathione peroxidase activities and malondialdehyde content increasing proportionally to ammonia nitrogen concentration initially but declining over time. Concurrently, gill Na⁺-K⁺-ATPase activity was significantly suppressed, while the gene expression of ammonia transporters (rhag, rhbg, and rhcg) exhibited ammonia nitrogen concentration-dependent upregulation, inversely correlated with the exposure duration. Histological gill damage intensified at higher concentrations. Hepatic ammonia detoxification enzymes activities (asparagine synthase, glutamine synthetase, and glutamate dehydrogenase) and glutamine accumulation increased with ammonia nitrogen levels, aligning with gene expression trends, though enzyme activity diminished over time. Serum alanine aminotransferase and aspartate aminotransferase activities and their gene expressions rose with ammonia nitrogen levels, while total protein declined. These findings demonstrate that chronic ammonia nitrogen stress disrupts antioxidant capacity, osmoregulation, and nitrogen metabolism, compelling Chinese perch to mitigate toxicity via glutamine synthesis. To ensure sustainable aquaculture, ammonia nitrogen levels should remain below 1.29 mg/L under adequate dissolved oxygen conditions. Full article

Background: The development of cerebral organoids created from human pluripotent stem cells in 3D culture may greatly improve the discovery of neuropsychiatric medicines. Methods: In the current study we differentiated neural organoids from a human pluripotent stem cell line in vitro, recorded the development of neurophysiological activity using multielectrode arrays (MEAs) and characterized the neuropharmacology of synaptic signaling over 8 months in vitro. In addition, we investigated the ability of these organoids to display epileptiform activity in response to a convulsant agent and the effects of antiseizure medicines to inhibit this abnormal activity. Results: Single and bursts of action potentials from individual neurons and network bursts were recorded on the MEA plates and significantly increased and became more complex from week 7 to week 30, consistent with neural network formation. Neural spiking was reduced by the Na channel blocker tetrodotoxin but increased by the inhibitor of K_V7 potassium channels XE991, confirming the involvement of voltage-gated sodium and potassium channels in action potential activity. The GABA antagonists bicuculline and picrotoxin each increased the spike rate, consistent with inhibitory synaptic signaling. In contrast, the glutamate receptor antagonist kynurenic acid inhibited the spike rate, consistent with excitatory synaptic transmission in the organoids. The convulsant 4-aminopyridine increased spiking, bursts and synchronized firing, consistent with epileptiform activity in vitro. The anticonvulsants carbamazepine, ethosuximide and diazepam each inhibited this epileptiform neural activity. Conclusions: Together, our data demonstrate that neural organoids form inhibitory and excitatory synaptic circuits, generate epileptiform activity in response to a convulsant agent and detect the antiseizure properties of diverse antiepileptic drugs, supporting their value in drug discovery. Full article

Salt stress poses a significant threat to crop growth. While brassinolide (BR) has been shown to alleviate its adverse effects and modulate plant development, the precise mechanism underlying BR-induced salt tolerance in rice remains unclear. In this study, the Chaoyouqianhao and Huanghuazhan rice varieties were employed to investigate the effects of BR seed soaking on the seedling phenotype, physiology, transcriptome, and metabolome under salt stress. The results demonstrated that BR treatment significantly enhanced rice plant height, root length, biomass, and antioxidant enzyme activities, while reducing leaf membrane damage, promoting ion homeostasis, and improving the photosynthetic capacity and salt tolerance. The transcriptome analysis revealed that BR regulated the expression of 1042 and 826 genes linked to antioxidant activity, ion homeostasis, photosynthesis, and lipid metabolism under salt stress. These included genes involved in Na⁺ efflux (OsNCED2, OsHKT2;1, and OsHKT1;1), photosynthetic electron transport (OsFd5 and OsFdC1), photosystem II (OsPsbR1, OsPsbR2, and OsPsbP), and CO₂ fixation. The metabolomic analysis identified 91 and 57 metabolite alterations induced by BR, primarily linked to amino acid, flavonoid, and lipid metabolism, with notable increases in antioxidant metabolites such as lignanoside, isorhamnetin, and L-glutamic acid. The integrated analysis highlighted the pivotal roles of 12-OPDA in α-linolenic acid metabolism and genes related to lipid metabolism, JA metabolism, and JA signal transduction in BR-mediated salt tolerance. Full article

In this study, the effects of chicken breast meat samples cooked in the oven at different temperatures (180, 200, and 220 °C) and times (16, 24, and 32 min) on various quality parameters, lipid oxidation, free amino acid profile, and mineral contents were investigated. Chicken breast samples were also analyzed in terms of several qualitative properties (pH, TBARS, cooking loss, lightness, redness, and yellowness). Both cooking temperature and cooking time affected the qualitative properties. It was determined that the mineral contents of the samples were affected by cooking time and temperature. The mineral content of the samples varied between 1.47 mg kg⁻¹ and 1700.46 mg kg⁻¹. In addition, the analysis of mineral content revealed that the order of mineral abundance in chicken samples was K > Na > Ca > Mg > Zn > Cu. In terms of free amino acid profile, it was determined that essential amino acids methionine (70.71–156.67 mg 100 g⁻¹) and phenylalanine (29.41–44.41 mg 100 g⁻¹), and non-essential amino acids alanine (66.29–141.11 mg 100 g⁻¹), glutamate (76.64–104.39 mg 100 g⁻¹), and glycine (35.03–56.18 mg 100 g⁻¹) contents were the highest. It was determined that the free amino acid content of the samples varied between 1.71 and 156.67 mg 100 g⁻¹. In addition, it was found that the pH, TBARS, cooking loss, lightness, redness, and yellowness parameters were significantly affected (p < 0.01). Consequently, it was found that the cooking temperature and duration significantly influenced the nutritional composition of chicken breast meat. Cooking at 180 °C for 16 min was identified as the optimal condition for minimizing lipid oxidation and maximizing mineral content. Full article

Soil saline-alkalization is a key factor affecting rice growth and physiological metabolism, which leads to reduced yields. Endophyte EF0801 significantly promoted growth and improved its saline-alkali resistance. We investigated growth parameters and physiological indices of endophyte EF0801-infected and control rice seedlings under sodium carbonate (Na₂CO₃) stress. The results showed that endophyte-infected rice seedlings showed plant height increase by 1.25-fold, root length shortening by 0.79-fold, sucrose synthase (SS), sucrose phosphosynthase (SPS), hexokinase (HXK), and α-glucosidase (α-GC) activities increased by 0.15-fold, 0.29-fold, 0.06-fold, and 1.45-fold, respectively, and β-glucosidase (β-GC) activity decreased by 0.12-fold. Utilizing gas chromatography and mass spectrometry (GC-MS) technology and RNA sequencing (RNA-seq) technology, we identified 419 differentially expressed genes (DEGs) and 37 differentially accumulated metabolites (DAMs). Comprehensive enrichment analysis of DAMs and DEGs showed that 6 DEGs and 6 DAMs were strongly correlated with the mitigating effects of endophytes on rice leaves under Na₂CO₃ treatment, highlighting the co-enrichment in starch and sucrose metabolism, as well as alanine, aspartate, and glutamate metabolism. The gene encoding HXK was found to be upregulated in endophyte-infected rice seedlings under Na₂CO₃ stress. HXK plays a key role in the conversion of fructose and glucose to fructose 6-phosphate (F-6-P) and glucose 6-phosphate (G-6-P), which are important intermediates in cellular energy metabolism and glycolytic pathways, providing energy and biosynthesis of precursor substances. Our findings provide a potential perspective for unraveling the molecular response of endophyte-mediated saline-alkali resistance in rice leaves and a theoretical rationale for exploring the mechanisms of growth-promoting effects by endophytes. Full article

L-Glutamate (L-Glu) and its salt derivatives are widely used in the food industry as flavor enhancers. Although the consumption of these compounds is generally considered safe, some studies suggest that chronically consuming L-Glu may be associated with various disorders. In this study, Wistar pregnant rats were treated daily with 1 g/L of L-Glu in their drinking water throughout the gestational period. OPA-1, DRP-1, and mitofusin 2—key proteins involved in mitochondrial fusion and fission—were analyzed by Western blot. The results showed that L-Glu exposure significantly decreased DRP-1 levels, while OPA-1 and mitofusin 2 levels were unaffected. This was accompanied by a notable decrease in mitochondrial complexes III and V. The activities of Mg²⁺-ATPase and Na⁺/K⁺-ATPase were also analyzed in fetal cerebellar plasma membranes. Maternal L-Glu intake significantly increased Mg²⁺-ATPase activity. Regarding Na⁺/K⁺-ATPase, the data showed that L-Glu exposure did not modulate the protein level or its activity. However, a positive interaction with glutamate receptors was observed in both activities, although neither AMPA nor NMDA receptors appeared to be involved. These results suggest that chronic maternal L-Glu intake during gestation modulates Mg²⁺-ATPase activity and protein markers of mitochondrial dynamics in the fetal cerebellum, which could affect neonatal development. Full article

Excessive ammonia accumulation poses a significant threat to aquatic species. Potamocorbula ustulata, known for its burrowing behavior and high population density, may experience elevated ammonia levels in its environment. However, its ammonia stress response mechanisms remain unclear. This study investigates the physiological and molecular responses of P. ustulata to acute ammonia exposure. Antioxidant enzyme activity was significantly altered in the gills and hepatopancreas, with GS, GDH, and ARG levels markedly increasing in the hepatopancreas. Transcriptome analysis revealed that after 24 h of exposure, differentially expressed genes (DEGs) were enriched in apoptosis and inflammation-related pathways (MAPK, NF-kB, NOD-like receptor signaling). By 96 h, DEGs in the gills were associated with nitrogen metabolism and transport, while those in the hepatopancreas were linked to oxidative phosphorylation and amino acid metabolism. Key ammonia transport and excretion genes, including V-type H⁺-ATPase, Ammonium transporter Rh, and Na⁺/K⁺-ATPase, were significantly upregulated in the gills, while glutamine synthetase and glutamate dehydrogenase were upregulated in the hepatopancreas (p < 0.05). These findings suggest that ammonia stress disrupts antioxidant defense, triggers inflammation and apoptosis, and enhances ammonia tolerance through excretion, glutamine conversion, and urea synthesis. This study provides insights into the molecular mechanisms underlying ammonia tolerance in bivalves. Full article

The retinal network relies on glutamate, the primary excitatory neurotransmitter involved in the visual cycle. Glutamate transactions are carried out by an array of distinct receptors and transporters distributed across both pre- and post-synaptic neurons and Müller radial glial cells. Glutamate receptors are broadly divided into two types: ionotropic and metabotropic receptors that differ in their molecular architecture and signaling properties. Within the retina, Müller glia cells span across its entire layers and possess specialized features that enable them to regulate glutamate extracellular levels and thus, its neuronal availability. In order to prevent an excitotoxic insult, retina extracellular glutamate levels have to be tightly regulated through uptake, predominantly into Müller glial cells, by a family of Na⁺-dependent glutamate transporters known as excitatory amino acid transporters. An exquisite interplay between glutamate receptor signaling and glutamate transporter expression and function is fundamental for the integrity and proper function of the retina. This review examines our current understanding of the impact of Müller glial glutamate signaling on glia/neuronal coupling. Full article

The purpose of this research was to investigate the characteristics of different plant-based sources rich in protein, chickpea flour (CPF), hazelnut oil cake (HOC), soy protein isolate (SPI) and concentrate (SPC), and pea protein isolate (PPI) for their subsequent use in the manufacture of meat analogs. The protein sources were analyzed for dry matter, ash, protein, fat, starch, dietary fiber, water holding capacity, granulosity, color parameters (L*, a*, b*, C*, YI), antioxidant activity before and after gastrointestinal in vitro digestion, and amino acid and mineral compositions. The highest dry matter content was determined in hazelnut oil cake and pea protein isolate. For the protein content, maximum values were obtained for the protein isolate and concentrate samples, from 52.80% to 80.50%, followed by hazelnut oil cake and chickpea flour. The water-holding capacity of all plant sources was directly influenced by the values of protein content, dietary fiber, and granulosity. The results obtained after gastrointestinal digestion also showed quite significant antioxidant activity, which is due to the process of hydrolysis and denaturation of plant-based protein sources in the gastrointestinal tract. Major amino acids identified in the analyzed samples were glutamic acid, leucine, arginine, phenylalanine, serine, valine, alanine, and tyrosine from minerals P, Na, Mg, and Ca. Principal component analysis (PCA) was used to illustrate the relationship between physicochemical characteristics, amino acid composition, mineral composition, and antioxidant activity determined in the plant-based materials. Full article

Phenolic compounds are harmful organic pollutants found in wastewater from the chemical and pharmaceutical industries, which are frequently accompanied by high saline concentrations. Microorganism-based biodegradation represents an environmentally friendly and cost-effective strategy for phenol removal. In this study, we isolated a bioflocculant-producing Bacillus paralicheniformis BL-1 that is capable of phenol degradation in high-salinity conditions. Differential gene expression analysis revealed the down-regulation of genes related to the synthesis of extracellular polymeric substances and the up-regulation of poly-γ-glutamate biosynthesis in 10% NaCl conditions. These findings indicate that poly-γ-glutamate is the main large biomolecule produced by B. paralicheniformis BL-1. A further investigation suggested that salinity stress resulted in the down-regulated expression of the genes involved in iron homeostasis. Therefore, alleviating iron limitation by supplying excess iron could improve cell growth and, thus, increase the phenol removal rate and flocculating activity. The productivity of poly-γ-glutamate reached 2.23 g/L, and the phenol removal rate reached 73.83% in the synthetic medium supplemented with 10% NaCl, 500 mg/L phenol, and 250 μM FeCl₃. Full article

The umami taste is well validated in Asian culture but remains less recognized and accepted in European cultures despite its presence in natural local products. This study explored the sensory and emotional perceptions of umami in 233 Austrian participants who had lived in Austria for most of their lives. Using blind tasting, participants evaluated monosodium glutamate (MSG) dissolved in water, providing open-ended verbal descriptions, pleasantness ratings, and comparisons to a sodium chloride (NaCl) solution. Discrimination tests excluded MSG ageusia, and basic demographic data were collected. A text semantic-based analysis (TSA) was employed to analyze the emotional valence and descriptive content of participants’ responses. The results showed that MSG was predominantly associated with neutral sentiments across the group, including both female and male subgroups. “Sour” was the most frequent taste descriptor, while “unfamiliar” characterized the perceptual experience. Pleasantness ratings for MSG and NaCl were positively correlated, suggesting that overcoming the unfamiliarity of umami could enhance its acceptance and align it with the pleasantness of salt. These findings advance the understanding of umami sensory perception and its emotional and cultural acceptance in European contexts, offering valuable insights for integrating umami into Western dietary and sensory frameworks. Full article

Nociceptive information is transmitted by action potentials (APs) through primary afferent neurons from the periphery to the central nervous system. Voltage-gated Na⁺ channels are involved in this AP production, while transient receptor potential (TRP) channels, which are non-selective cation channels, are involved in receiving and transmitting nociceptive stimuli in the peripheral and central terminals of the primary afferent neurons. Peripheral terminal TRP vanilloid-1 (TRPV1), ankylin-1 (TRPA1) and melastatin-8 (TRPM8) activation produces APs, while central terminal TRP activation enhances the spontaneous release of L-glutamate from the terminal to spinal cord and brain stem lamina II neurons that play a pivotal role in modulating nociceptive transmission. There is much evidence demonstrating that chemical compounds involved in Na⁺ channel (or nerve AP conduction) inhibition modify TRP channel functions. Among these compounds are local anesthetics, anti-epileptics, α₂-adrenoceptor agonists, antidepressants (all of which are used as analgesic adjuvants), general anesthetics, opioids, non-steroidal anti-inflammatory drugs and plant-derived compounds, many of which are involved in antinociception. This review mentions the modulation of Na⁺ channels and TRP channels including TRPV1, TRPA1 and TRPM8, both of which modulations are produced by pain-related compounds. Full article

Scutellaria baicalensis Georgi is a valuable medicinal plant of the Lamiaceae family. Its roots have been used in Traditional Chinese Medicine (under the name Huang-qin) since antiquity and are nowadays included in Chinese and European Pharmacopoeias. It is abundant in bioactive compounds which constitute up to 20% of dried root mass. These substances are lipophilic flavones with unsubstituted B-ring, baicalein, and wogonin and their respective glucuronides–baicalin and wogonoside being the most abundant. The content of these compounds is variable and the environmental factors causing this remain partially unknown. The role of these compounds in stress response is still being investigated and in our efforts to measure the effect of NaCl treatment on S. baicalensis growth and metabolic profile, we hope to contribute to this research. Short-term exposure to salt stress (50, 100, and 150 mM NaCl) resulted in a marked increase of baicalein from 1.55 mg to 2.55 mg/g DM (1.6-fold), baicalin from 8.2 mg to 14.7 mg (1.8-fold), wogonin from 4.9 to 6.8 (1.4-fold), and wogonoside from 3.3 to 6.8 mg/g DM (2-fold) in the roots. Conversely, in the aerial parts, the content of individual major flavonoids: carthamidine-7-O-glucuronide and scutellarein-7-O-glucuronide decreased the most by 10–50% from 18.6 mg to 11.3 mg/g (1.6-fold less) and from 6.5 mg to 3.4 mg/g DM (0.52-fold less), respectively. The amino acid profile was also altered with an increase in root concentrations of the following amino acids: arginine from 0.19 to 0.33 mg/g (1.7-fold), glutamate from 0.09 to 0.16 mg/g DM (1.6-fold), alanine from 0.009 to 0.06 mg/g (6.8-fold), proline from 0.011 to 0.029 (2.4-fold) and lysine from 0.016 to 0.063 mg/g (3.9-fold). Aspartate concentration decreased from 0.01 to 0.002 mg/g (4.8-fold less) at 150 mM NaCl. In the aerial parts, the concentration and variation in levels of specific amino acids differed among groups. For instance, the glutamate content exhibited a significant increase exclusively in the treatment group, rising from 0.031 to 0.034 mg/g, representing a 1.2-fold increase. Proline concentration showed a marked increase across all treated groups with the highest from 0.011 to 0.11 mg/g (10-fold). In conclusion, moderate salt stress was shown to increase S. baicalensis root biomass and flavonoid content which is rarely observed in a glycophyte species and provides a foundation for further studies on the mechanisms of osmotic stress adaptation on the specialized metabolism level. Full article

In our diet, we ingest a variety of compounds that are TRPV1 modulators. It is important to understand if these compounds alter neural and behavioral responses to taste stimuli representing all taste qualities. Here, we will summarize the effects of capsaicin, resiniferatoxin, cetylpyridinium chloride, ethanol, nicotine, N-geranyl cyclopropylcarboxamide, Kokumi taste peptides, pH, and temperature on neural and behavioral responses to taste stimuli in rodent models and on human taste perception. The above TRPV1 agonists produced characteristic biphasic effects on chorda tympani taste nerve responses to NaCl in the presence of amiloride, an epithelial Na⁺ channel blocker, at low concentrations enhancing and at high concentrations inhibiting the response. Biphasic responses were also observed with KCl, NH₄Cl, and CaCl₂. In the presence of multiple stimuli, the effect is additive. These responses are blocked by TRPV1 antagonists and are not observed in TRPV1 knockout mice. Some TRPV1 modulators also increase neural responses to glutamate but at concentrations much above the concentrations that enhance salt responses. These modulators also alter human salt and glutamate taste perceptions at different concentration ranges. Glutamate responses are TRPV1-independent. Sweet and bitter responses are TRPV1-independent but the off-taste of sweeteners is TRPV1-dependent. Aversive responses to acids and ethanol are absent in animals in which both the taste system and the TRPV1-trigeminal system are eliminated. Thus, TRPV1 modulators differentially alter responses to taste stimuli. Full article

This experimental study was performed to evaluate the alterations in the expression of a few subunits composing glutamate AMPA (a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) and NMDA (N-methyl-D-aspartate) receptors in the hippocampal cells of Wistar rats in response to long-term fluoride (F^-) exposure. The animals were given water with background 0.4 (control), 5, 20, and 50 ppm F^- (as NaF) for 12 months. The cognitive capacities of rats were examined by novel object recognition (NOR), Y-maze test, and Morris water maze tests. RT-qPCR and Western blotting techniques were used to evaluate the expression of different AMPA and NMDA subunits at transcriptional and translational levels, respectively. Long-term F^- poisoning disturbed the formation of hippocampus-dependent working spatial and long-term non-spatial memory. The expression of Gria1, Gria2, and Gria3 genes encoding different subunits of AMPA receptors were comparable in hippocampi of control and F^--exposed animals, although the levels of both Grin2a and Grin2b mRNA increased. Long-term F^- intake enhanced the ratio of phospho-GluA1/total-GluA1 proteins in subcellular fraction enriched with cytosolic proteins, while decreased content of GluA2 but elevated level of GluA3 were observed in subcellular fraction enriched with membrane proteins. Such changes were accompanied by increased phosphorylation of GluN2A and GluN2B subunits, higher ratios of GluN2A/GluN1 and GluN2B/GluN1 proteins in the cytosol, and GluN2A/GluN2B ratio in membranes. These changes indicate the predominance of Ca²⁺-permeable AMPARs in membranes and a shift between different NMDARs subunits in hippocampal cells of F^--exposed rats, which is typical for neurodegeneration and can at least partially underly the observed disturbances in cognitive capacities of animals. Full article