Hyaluronic acid-ethylenediamine-cinnamic acid attenuates IBS-D via regulating 5-hydroxytryptamine signaling pathway, intestinal barrier and gut microbiota.

Ca2+ binding to soluble extracellular polymeric substances promotes loosening of Microcystis colonies under high Ca2+conditions.

In mammalian sperm, the regulation of intracellular calcium (Ca2+) is essential for fertility. Semen processing for assisted reproduction may disturb Ca2+ homeostasis. This study aimed to investigate whether chilling boar sperm to 5 °C and subsequent storage affect the function of intracellular Ca2+ stores. Semen was stored in BTS-extender at 5 °C or 17 °C (control) for up to five days. Fluo-4/AM-loaded aliquots were incubated in Ca2+-free Tyrode’s medium at 38 °C. Sperm preserved at 17 °C had higher free intracellular Ca2+ levels compared with those stored at 5 °C (p < 0.05). However, there was no difference between storage groups in Ca2+ levels during incubation at 38 °C. Thimerosal, a sensitizer of Ca2+ channels, was added, and changes in the free intracellular Ca2+ concentration were monitored in viable acrosome-intact sperm by continuous flow cytometry. There was no effect of storage temperature on the kinetic response to thimerosal at days 1 and 3. At day 5, the relative increase in Ca2+ was higher in 5 °C-stored samples after 3 min of incubation. At 60 and 120 min of incubation, the thimerosal response was no longer influenced by the storage temperature or storage duration. In conclusion, chilling and storage do not affect the release dynamics of free Ca2+ from intracellular stores in viable boar sperm after rewarming.

The effectiveness of Fiber-Reinforced Polymer (FRP) reinforced with Engineered Cementitious Composites (ECC) for strengthening concrete structures is critically dependent on the interfacial bond between the ECC overlay and the substrate concrete. This study investigates the efficacy of interfacial agents in enhancing this bond and delves into the underlying mechanisms through single-sided shear tests and micro-scale measurements. The results demonstrate that the application of a silicate-based activator including titanium fluoride (Z3 agent) yielded the most significant improvements, with increases of 70.8% in shear strength compared to untreated specimens. Micro-scale analysis revealed that the Z3 agent deeply penetrates the interfacial transition zone, reacting with free Ca(OH)2 to form solid precipitates that densify the pore structure and enhance mechanical properties. Based on the experimental data, a highly accurate practical model for predicting bond strength is proposed, which explicitly incorporates the contributions of surface roughness, concrete strength, and the interfacial agent.

Drought stress is a significant environmental threat to global agricultural production and distribution. Plant adaptation to dehydration stress involves intricate biological processes with substantial changes in metabolite composition. In this study, we investigated the role of tricarboxylic acid (TCA) cycle metabolites in drought tolerance in grapevine and Arabidopsis by metabolome, live cell imaging, electrophysiological and pharmacological approaches. Metabolome analysis revealed that amount of malate, citrate, and isocitrate increased over time in detached grapevine leaves. Ca2+ imaging and ion channel measurements indicated that fumarate, malate, and α-ketoglutarate induced cytosolic free Ca2+ concentration ([Ca2+]cyt) elevation in guard cells and directly activated a guard-cell anion channel SLOW ANION CHANNEL-ASSOCIATED 1 (SLAC1). However, only malate induced stomatal closure, which required increases in [Ca2+]cyt in guard cells and activation of SLAC1. Through pharmacological experiments and reverse genetics analyses, G-proteins were identified as essential components of malate signaling by regulating second messenger production. These results indicate that TCA cycle metabolites are sensed individually by guard cells and that malate plays a key role in connecting metabolic regulation and drought tolerance through G-protein-dependent signal cascades.Supplementary InformationThe online version contains supplementary material available at 10.1186/s43897-025-00181-z.

Methylmercury (MeHg) is a potent neurotoxin that can cross the blood-brain barrier and disrupt neurological function in animals. Emerging evidence suggests that MeHg neurotoxicity may originate from compromised astrocytes, as they are strategically positioned to metabolize and process substances that enter the central nervous system. Thus, a better characterization of the timely cellular responses of astrocytes upon MeHg exposure is key to delineating the toxicology of MeHg. Here, MeHg exposure caused a transient increase in reactive oxygen species (ROS) and intracellular calcium concentration ([Ca²⁺]i), which peaked within 3 h and 30 min, respectively, in astrocytes. Further analyses indicated that the increase in [Ca²⁺]i after MeHg exposure might involve both extracellular Ca²⁺ influx and Ca²⁺ release from intracellular stores, as evidenced by alteration of Ca²⁺ dynamics in cells by targeting specific Ca²⁺ channels with blockers. Further cytotoxicity analyses revealed that antagonizing Ca²⁺-dependent signaling pathways and ROS levels markedly protected astrocytes against MeHg-induced cell death. Treatment with lipopolysaccharide improved cell survival under MeHg exposure, suggesting a reciprocal interaction of proinflammatory signaling and MeHg on [Ca²⁺]i kinetics and nitric oxide production. Collectively, our findings indicated that transient alterations in free radical and Ca²⁺ levels in astrocytes may be associated with MeHg-induced cytotoxicity. Targeting oxidative stress and Ca²⁺ signaling in astrocytes may provide potential strategies for mitigating MeHg-induced neurotoxicity.

The improving effect of Pleurotus ostreatus polysaccharide-EGCG active preservative films on the functional properties of myofibrillar proteins in refrigerated pork.

To investigate cerebral vasorelaxation of total flavonoids of Chuzhou chrysanthemum (TFCC) in rats and its mechanism. Cerebral basilar arteries (CBA) of rats were isolated, and the vasodilation induced by TFCC (10-2,560 mg/L) following pretension with 100 nmol/L U46619 or 30 mmol/L KCl were measured using a pressure myograph system. Addition of H2S synthase cystathionine-γ-lyase (CSE) inhibitor dl-propargylglycine (PPG, 100 µ mol/L), a large-conductance Ca2+-activated potassium (BKCa) channel blocker iberiotoxin (IBTX,100 nmol/L) and L-type Ca2+ channel blocker nifedipine (100 nmol/L) were added to determine the effect of pretreatment with the inhibitors on TFCC-induced vasorelaxation. KCl (30 mmol/L) was used as a contractile agent, TFCC (3.3-270 mg/L)-induced relaxation was detected by measuring the length of the long axis of rat cerebral vascular smooth muscle cells (VSMCs). Determination of the effect of pretreatment of VSMCs by IBTX or nifedipine on TFCC-induced cellular relaxation, and intracellular free Ca2+ concentration ([Ca2+]i) was detected by fluorescent method. Endothelial cells (ECs) were co-cultured with VSMCs to observe the effect of endogenous H2S on TFCC-induced relaxation in VSMCs. TFCC caused a concentration-dependent vasorelaxation in the rat CBA precontracted with KCl or U46619 (P<0.01). Endothelial removal markedly attenuated this vasodilation, but the remaining vasorelaxation was still significant (P<0.01). The TFCC-induced cerebral vasorelaxation was remarkably inhibited by PPG, IBTX and nifedipine (P<0.01). TFCC caused a significant relaxation of rat CBA VSMCs (P<0.01). Co-culture with wild-type cerebral ECs but not with cystathionine-γ-lyase- or 3-mercaptosulfotransferase-knockout ECs markedly enhanced TFCC-induced relaxation of VSMCs (P<0.05) and increased H2S content (P<0.01). TFCC decreased the [Ca2+]i in VSMCs (P<0.01), which was attenuated by PPG and IBTX. TFCC dilated rat CBA in both endothelium-dependent and -independent manner. Its endothelium-dependent dilation was probably involved in the blockade of L-type Ca2+ channels caused by endothelial H2S activating BKCa channels in VSMCs; its endothelium-independent relaxation was primarily from the direct blockade of the L-type Ca2+ channels in VSMCs.

Elucidating the impact of trans-ned-19 on two-Pore channel 2 mutants of Dictyostelium: changes in intracellular calcium levels and subsequent effect on autophagic flux.

The cellular mechanisms for the age-related loss in skeletal muscle contractile function and increased fatigability are unresolved. We previously observed that the depressive effects of fatiguing levels of hydrogen (H+; pH 6.8, 6.6, and 6.2) and inorganic phosphate (Pi; 12, 20, and 30 mM) did not differ in myofibers from young compared with older adults. However, these studies used saturating Ca2+, while fatigue during high-intensity contractions in vivo also likely involves a decrease in myoplasmic free Ca2+. Thus, we compared the Ca2+ sensitivity of myofibers from 10 young (22.1 ± 3.6; 5 women) and 13 older (71.7 ± 5.5; 7 women) adults in conditions mimicking quiescent (pH 7 + 4 mM Pi) and fatigued (pH 6.2 + 30 mM Pi) muscle. Fast fiber cross-sectional area was ∼35% smaller in older (4,859 ± 2,116 µm2) compared with young (7,446 ± 2,399 µm2, P = 0.002), which corresponded with lower maximal absolute force (Po) in both quiescent (old = 0.75 ± 0.30 mN; young = 1.13 ± 0.32 mN; P = 0.002) and fatigue conditions (old = 0.35 ± 0.14 mN; young = 0.52 ± 0.16 mN; P = 0.002). There were no differences in fast fiber size-specific Po, indicating the age-related decline in force was due to differences in fiber size. Elevated H+ and Pi shifted the force-pCa relationship to the right, confirming nonhuman studies that these metabolites contribute to fatigue by depressing the sensitivity of the myofilaments to Ca2+. However, Ca2+ sensitivity was not different with age or sex in either condition, and the metabolite-induced shift in the force-pCa relationship did not differ with age in either the slow (P = 0.507) or fast (P = 0.115) fibers. These data suggest the age-related increase in fatigability of limb muscles cannot be explained by an increased sensitivity of the myofibers to elevated H+ and Pi in maximal or submaximal Ca2+.NEW & NOTEWORTHY This study reports the effects of elevated H+ and Pi on Ca2+ sensitivity of human skeletal muscle fibers and determines whether the effects of these metabolites are altered by aging in submaximal Ca2+. The metabolites markedly depressed Ca2+ sensitivity in human muscle fibers, but there was no effect of age or sex. These data suggest that Ca2+ sensitivity is preserved with age in conditions that mimic both quiescent and fatigued muscle.

This study evaluated liposomes prepared using three food-grade lecithins-SLP-WHITE and SLP-PC70 (soy-derived), and PL-30S (egg yolk-derived)-to enhance the food function and delivery of p-coumaric acid (CA), a phenolic antioxidant extracted from sugarcane bagasse. Among the tested formulations, liposomes composed of SLP-WHITE and PL-30S at a 90:10 (w/w) ratio exhibited the highest encapsulation efficiency (82%). Notably, dynamic light scattering and confocal laser scanning microscopy revealed a strong negative zeta potential (-75.26 mV), small particle size (~100 nm), and a unilamellar structure, confirming this formulation as the optimum condition. Interestingly, encapsulated CA prepared with this optimum combination retained its antioxidant activity for 28 days. Furthermore, in a Caco-2 monolayer model, the liposomal CA showed significantly improved intestinal permeability compared to free CA, suggesting enhanced bioavailability via endocytic uptake. These results demonstrate that rational combinations of food-grade lecithins with complementary characteristics-such as the electrostatic stability of SLP-WHITE and membrane rigidity from PL-30S-can improve both physical stability and functionality of liposomes. This study provides a practical strategy for developing functional liposomal carriers suitable for food applications, particularly for delivering poorly bioavailable phenolic compounds like p-coumaric acid.

Light responsiveness is a fundamental characteristic of eukaryotic organisms, both unicellular and multicellular. However, no photoresponsive behavior has previously been reported in Apusomonadida—a group of small, free-living biflagellates phylogenetically positioned as the sister group to Opisthokonta (comprising animals, fungi, and their unicellular relatives). As such, apusomonads are critical for understanding the evolutionary origins of opisthokonts. Here, we report an avoidance response to blue light in the apusomonad Podomonas kaiyoae. This response is characterized by an increase in gliding velocity, transient changes in flagellar waveforms, and alterations in cell shape. Dynamic cell contraction is triggered by an increase in intracellular free Ca²⁺ and is inhibited by either a dynein inhibitor or an actin-disrupting agent. These findings suggest that the photophobic behavior of Podomonas kaiyoae depends on cytoskeletal responses mediated by both the dynein/tubulin and myosin/actin systems, which likely originated early in eukaryotic evolution. The functional dominance of the posterior flagellum in cilia-driven directional changes further supports the phylogenetic placement of apusomonads as the sister group to opisthokonts, rather than to other eukaryotic lineages.

In this work, a complex and eco-friendly biomass raffinose monomer-modified polycarboxylate superplasticizer (RAF-PCE) was designed and synthesized via the free radical polymerization technique to simultaneously improve paste fluidity and delay fluidity loss in concrete applications. The adsorption, fluidity, and early hydration behaviors of cementitious systems after the introduction of RAF-PCE have been systematically investigated. Experimental results demonstrate that the hydroxy group in raffinose promotes the adsorption of RAF-PCE on the cement particles, thereby elevating the dispersion characteristic of cement paste through electrostatic repulsion, enabling excellent initial fluidity (310 mm). Additionally, its steric hindrance effect has also been identified to play a role in improving paste fluidity and reducing the slump loss of cement slurry. Detailed analyses unveil that RAF-PCE can reduce the concentration of free Ca2+ in the pore solution through complexation with Ca2+, which prevents the early precipitation of hydration products and realizes a delayed effect on cement hydration, ultimately evolving into a homogeneous and compact microstructure for superior compressive tensile strength of the cement mortar. The 28-day compressive strength of cement incorporating RAF-PCE reached 79.2 MPa, representing a 5.5% enhancement over conventional PCE systems. Our work provides novel insights into the promotion of innovative and green development in the concrete industry by utilizing renewable biomass resources for high-performance materials.

Ca2+ flux in plant responses to abiotic stress.

Optical activation or δ-cells stimulate somatostatin secretion. δ-Cell depolarization evokes β-cell action potential firing and insulin release. δ-Cell activation results in islet-wide synchronized β-cell cytoplasmic free Ca2+ concentration increases. δ-Cell inhibition aborts cytoplasmic free Ca2+ concentration oscillations in β-cell neighbors.

Cementoblasts play essential roles in secreting collagenous and non-collagenous matrix proteins and in mineralization to produce cementum. Cementum is a mineralized tissue deposited in layers on the surface of the tooth root, where it is subjected throughout life to mechanical stresses including chewing and occlusal forces. To date, the detailed mechanosensitivity mechanisms regulating cementoblasts remain unclear. We investigated cellular functions driven by mechanosensitive processes in human cementoblasts (HCEM) by analyzing protein expression using immunofluorescence staining and mechanical stimulation-induced Ca2+ signaling by measuring intracellular free Ca2+ concentration ([Ca2+]i) using the Ca2+ indicator fura-2. We also assessed cell proliferation modulation using colony-forming unit fibroblast (CFU-F) analysis, and mineralization efficacy using Alizarin Red and von Kossa staining. HCEM were immunopositive for cementoblast marker proteins, cementum attachment protein, and cementum protein 1, and the mechanosensitive cation channels Piezo1 and Piezo2. Both direct mechanical stimulation and pharmacological stimulation with the Piezo1 activator Yoda1 elicited transient increases in [Ca2+]i, which were significantly suppressed by Dooku1, a pharmacological Yoda1 inhibitor. In the CFU-F assay, colony formation was significantly enhanced by treatment with pharmacological Piezo1 inhibitors, and by GsMTx4, Dooku1, and Piezo1 gene silencing, but was suppressed by Yoda1. HCEM mineralization efficacy was significantly promoted by Yoda1 but significantly suppressed by GsMTx4, Dooku1, and Piezo1 gene silencing. Piezo1 suppresses colony formation, but activates HCEM-mediated mineralization, suggesting that Piezo1-induced Ca2+ signaling plays an important role in cementum mineralization and deposition by cementoblasts.

The role of bile salts in itch receptor activation.

Comparative study on Acetobacter-mediated calcium release and speciation from diverse animal-derived calcium powders: eggshell, oyster, chicken bone, and beef bone.

In the post-fire stage, precipitation and superficial incorporation of ashes alter the chemical properties of the soil. This study evaluated the combined effects of spectral preprocessing methods, data partitioning strategies, and modeling approaches on soil pH prediction using a portable near-infrared (NIR) spectrometer in wildfire ash-enriched soil. A laboratory column experiment was conducted using disturbed sandy loam soil, in which wildfire ashes were incorporated. The experimental design considered five treatments (n = 3) of Eucalyptus globulus and Quillaja saponaria ash incorporations (C: no ash; T1: 2% ash at 2.5 cm; T2: 2% ash at 5 cm; T3: 4% ash at 2.5 cm; T4: 4% ash at 5 cm). After simulating a precipitation of 20 mm h-1 for 6 hours, the soil columns were sampled at 5 depths (D1: 2-3 cm, D2: 7-8 cm, D3: 12-13 cm, D4: 16-17 cm, D5: 20-21 cm). The samples were analyzed using a NIR spectrometer (range: 1350-2550 nm), and the levels of pH (1:2.5) were determined in the laboratory. Eight preprocessing techniques (P0 to P7) were tested, including absorbance conversion, mean centering, trimming, smoothing, standard normal variate (SNV), moving window average (MWA), Savitzky-Golay filtering, and first derivative transformation. Using the Kennard-Stone method, 70% of the data was used for calibration (CAL) and 30% for validation (VAL), considering two partitioning approaches, the same partition by pseudo absorbance values (Scenario A) and different partitions by preprocessing method (Scenario B). Partial least square (PLS) and random forest (RF) models were applied, and performance was assessed using root mean square error (RMSE), coefficient of determination (r2), and ratio of performance to interquartile distance (RPIQ) analyses. The most accurate pH predictions were achieved with RF under Scenario B using trimming + standard normal variate (SNV) + moving weighted average (MWA) preprocessing, yielding r2 values of 0.95 (CAL) and 0.91 (VAL), with RMSEs of 0.23 (CAL) and 0.57 (VAL), and RPIQs of 4.33 (CAL) and 4.61 (VAL). Overall, portable NIR spectroscopy demonstrated strong potential for soil pH prediction in ash-enriched soil, emphasizing the critical role of appropriate spectral preprocessing to avoid overfitting. These findings provide insights into applying portable NIR spectroscopy as a cost-effective tool for monitoring soil pH following wildfires.

Background Microglia are brain resident cells that control neural network maintenance, damage healing, and brain development. Microglia undergo apoptosis, cytokine production, and reactive free radicals of oxygen (ROS) in response to lipopolysaccharide (LPS) stimulation. TRPM2 is activated by LPS-induced oxidative stress, but it is inhibited by carvacrol (CARV) and N-(p-amylcinnamoyl)anthranilic acid (ACA). Morphine (MRP), an opioid ligand, has the potential to be both an anesthetic and an antioxidant. Objective We investigated how MRP changed the TRPM2 signaling pathways to protect murine BV-2 microglia cells from LPS-induced ROS, cytokine production, and death. Materials and Methods We generated five primary groups in the cultured BV-2 cells: Control, MRP (50 μM for 24h), LPS (1 μg/ml for 24h), LPS + MRP, and LPS + TRPM2 blockers (ACA or CARV). Results The incubation of LPS increased the amounts of apoptosis, cell death (propidium iodide positive cell number), oxidants (ROS and lipid peroxidation), mitochondrial dysfunction, apoptotic markers (caspase −3, −8, and −9), cytokines (TNF-α, IL-1β, and IL-6), death cell waste (debris), cytosolic free Ca2+, Zn2+, and ADP-ribose-induced TRPM2 current densities, while the treatments of MRP and TRPM2 blockers reduced their amounts. The LPS-induced reductions in BV-2 viability percentage, BV-2 number, glutathione peroxidase activity, and glutathione levels were increased by the treatments. Conclusions MRP reduced the levels of LPS-induced oxidative stress, inflammatory cytokines, and apoptosis via inhibiting TRPM2 in the BV-2 cells. One possible treatment option for oxidative microglia damage and neurological disorders induced by LPS could be the MRP.