Search Results (229)

Environmental pH plays a critical role in microbial fermentation processes. Weizmannia coagulans attracts particular attention for exceptional acid tolerance and lactic acid productivity. Yet acidic stress impacts on its cell division regulation remain unclear. Here, a critical pH value (pH 4.20) for growth inhibition of the Gram-positive bacterium Weizmannia coagulans strain BC99 was first established. Transcriptomic analysis of metabolic pathways was then performed. The multi-layered regulatory network underlying acid stress-induced cell division was elucidated. Integrated transcriptomic and physiological analyses reveal that acid stress triggers multigene expression reprogramming. This drives core metabolic network reorganization, coordinately regulating division processes. RNA-seq analysis demonstrated acid stress triggered differential expression of division genes (FtsZ/Q downregulation), ATP synthase suppression, and peptidoglycan transport reduction, while enhancing membrane rigidification (Cfa) and magnesium homeostasis (CorA). The PhoPR dual-component system emerged as a central regulator, inhibiting septal assembly via RipA hydrolase and RpsU ribosomal suppression while rerouting carbon flux to glycolysis, elucidating bacterial acid adaptation mechanisms. Collectively, these adaptive changes prioritize cell survival over active proliferation under acidic conditions. This study provides molecular insights into how W. coagulans preserves viability under acid stress, offering a theoretical basis for optimizing its performance in probiotic applications. Full article

The preservation of rooster semen quality during short-term liquid storage remains a challenge in poultry reproductive biotechnology because sperm cells rapidly lose functional competence under ambient conditions. This deterioration is largely associated with oxidative stress and lipid peroxidation of sperm membranes, which are particularly vulnerable in avian species due to their high polyunsaturated fatty acid content and limited cytoplasmic antioxidant defenses. Selenium is an essential trace element involved in cellular antioxidant protection through its incorporation into several selenoproteins that regulate redox balance and protect cellular structures from oxidative injury. The present study evaluated the effects of selenium methionine supplementation on rooster semen quality during liquid storage at 25 °C. Semen was diluted using a standard poultry semen extender composed of sodium glutamate, glucose, potassium acetate, magnesium acetate, and potassium citrate. Selenium methionine was incorporated into the semen extender at concentrations of 0.5%, 1%, and 2% (w/v) at the time of semen dilution prior to storage. Semen quality was assessed at 0, 4, 8, 12, and 24 h of storage. Functional parameters, including total sperm motility, sperm viability, and dead sperm percentage, together with kinematic variables (VSL, VCL, VAP, ALH, LIN, and STR), were analyzed using computer-assisted sperm analysis (CASA). Structural integrity was evaluated through acrosome and plasma membrane integrity tests, while sperm physiological status and apoptotic progression were assessed using Annexin V-FITC/propidium iodide flow cytometry. Significant effects of storage time, selenium methionine concentration, and their interaction were observed for multiple semen quality parameters (p < 0.05). Among the tested concentrations, supplementation with 0.5% selenium methionine consistently produced the most favorable results, maintaining higher sperm motility, viability, and membrane integrity while reducing dead sperm percentage and apoptotic progression during storage, with protective effects particularly evident at 8, 12, and 24 h compared with the control and higher concentrations. Polynomial contrast analysis indicated predominantly non-linear dose–response relationships, with quadratic and cubic components providing the best model fit (R² = 0.90–0.99; p < 0.0001), suggesting a hormetic antioxidant effect. Overall, these findings indicate that selenium methionine supplementation in semen extender improves the stability of rooster semen during short-term liquid storage at ambient temperature, with 0.5% showing the most consistent protective effects among the concentrations evaluated. Full article

The mechanism of action of drugs used to treat ADHD has not been fully elucidated. The aim of the study was to assess the effect of clonidine, a drug used to treat ADHD, on interictal-like epileptiform events in prefrontal cortex pyramidal neurons. Epileptiform events (lasting less than 3 s) were recorded in a zero-magnesium and elevated-potassium proepileptic extracellular solution using the patch-clamp methodology. Clonidine 100 µM reduced the frequency of epileptiform events. Moreover, clonidine hyperpolarized the membrane potential recorded in the proepileptic extracellular solution. In the constant presence of the alpha-2 adrenergic receptor antagonist idazoxan 20 µM in all solutions, clonidine 100 µM also inhibited the frequency of interictal-like epileptiform events. This suggests that clonidine inhibited the frequency of interictal events via a direct influence on ionic channels. Furthermore, clonidine inhibited tonic NMDA receptor currents and did not influence tonic AMPA currents. The tested drug inhibited fast-inactivating voltage-gated sodium currents. Blockade of NMDA currents and voltage-gated sodium currents likely contributed to the inhibition of epileptiform events exerted by clonidine. The potential translational relevance of the study is discussed. Full article

Maintaining a membrane electrical potential of biological cells is a dynamic process, as some cells have a continually changing potential, like pacemaker cells, while other cells may function with large or small changes in the membrane potential. Additionally, some cells may change their electrical potential when stimulated or inhibited by electrical signals, chemical compounds, or both—either simultaneously or episodically. The persistent leak of K⁺ through two-pore-domain potassium channels (K2P) and of Na⁺ through Na⁺ leak channels (NALCNs) and the action of pumps and exchangers are primarily responsible for maintaining a resting potential. Ca²⁺ ions are known to block the NALCNs and result in a more hyperpolarized membrane potential, with a reduction in Ca²⁺ resulting in a depolarized state. Using the larval muscles of Drosophila, the membrane potentials were monitored as Ca²⁺ and Mg²⁺ concentrations were altered. Changes as large as 20 mM of Mg²⁺ had only small effects (1 to 2 mV) on the membrane potential compared to 3–5 mM changes in Ca²⁺ having larger effects (5–10 mV). Although, it appears raised [Mg²⁺] may dampen the changes induced by Ca²⁺. Simulations of the G-H-K equation estimate the changes in permeability of Na+ (pNa). These experiments are significant, as the clinical severity of hypocalcemia and hypercalcemia may also depend on Mg²⁺ levels. Full article

The industrial application of modified ion-exchange membranes is limited by complex, discontinuous ex-situ processes. This study introduces an in-situ electro-assembly strategy that enables the direct fabrication of a selective layer within an electrodialysis stack without disassembly. By utilizing a programmed current reversal to orchestrate the sequential deposition of polyethyleneimine (PEI), glutaraldehyde cross-linking, and polystyrene sulfonate (PSS) adsorption, we achieve meticulous interfacial engineering on a commercial cation exchange membrane. Comprehensive characterization confirms the successful construction of a hydrophilic, charge-tuned multilayer, which enhances ion transport kinetics and raises the limiting current density. This method culminates in a membrane with an exceptional Li⁺/Mg²⁺ selectivity of 107.9 and robust stability, retaining a significant selectivity of 47 over 10 cycles in real salt lake brine. This synergistic integration of operational simplicity, interfacial precision, and superior performance establishes a transformative and scalable platform for manufacturing high-performance membranes for selective ion separation from complex brine sources. Full article

Potassium mining activities result in the discharge of highly saline wastewaters, creating severe environmental impacts in water and soil. This study evaluates the environmental performance of a novel pilot system developed in the framework of the LIFE Brine-Mining project. The system comprises membrane, precipitation and thermal technologies, recovering high-purity water and five valuable resources from it: magnesium hydroxide, calcium carbonate, calcium sulfate, sodium chloride, and potassium chloride. A cradle-to-grave Life Cycle Assessment (LCA) was performed following the standards ISO14040 and EN15804 and using 1 m³ of potassium wastewater as functional unit. The LCA results indicated that the novel system environmental impact is mainly affected by the use of chemicals (20.63 × 10⁰ kg/FU) during its operation and energy consumption (1.39 × 10¹ kWh/FU). The chemical use dominates areas like the Abiotic Depletion, and the Eutrophication Potential, and the Water Depletion Potential. The novel pilot system was compared with another novel configuration that treated a brine from coal mining activities and with a conventional method of potassium brine management, which is the disposal in underground old mines. The potassium brine treatment system exhibited lower environmental impact than the coal mine brine system, and outperformed compared to the conventional disposal method. Full article

Background/Objectives: Dental implants are a preferred solution for missing teeth, but peri-implantitis remains a major challenge in implant dentistry. This narrative review provides an overview of the therapeutic interventions for peri-implantitis based on the current literature and illustrates a new clinical approach using novel magnesium membrane through three case presentations. Methods: A comprehensive literature search on peri-implantitis management was conducted, with emphasis on current clinical practice guidelines. In addition, three clinical cases were presented to demonstrate the use of a fully resorbable magnesium membrane in combination with a bovine xenograft with hyaluronate. Results: The narrative review identified and summarized a wide range of non-surgical and surgical therapeutic strategies for treatment of peri-implantitis. Additionally, three case reports with novel magnesium membrane highlighted distinct clinical scenarios: (1) bone defect reconstruction without implant removal, (2) reconstruction following implant removal, and (3) a minimally invasive shield technique performed without removal of the implant or crown. All cases demonstrated favorable clinical outcomes following the novel biomaterial approach. Conclusions: The combination of a resorbable magnesium membrane with bovine xenograft with hyaluronate represents a promising therapeutic strategy for treatment of peri-implantitis. This approach may improve clinical outcomes and potentially set new standards in implant dentistry. Further studies with larger cohorts and control groups are required to confirm these preliminary findings. Full article

Magnesium ion (Mg²⁺), particularly its free intracellular form, is indispensable for regulating diverse cellular functions. This critical role implies the existence of dedicated transporters and channels in the plasma membrane that coordinate Mg²⁺ uptake, intracellular storage, and efflux to maintain homeostasis. Although numerous molecular entities responsible for such Mg²⁺ transport have been reported over the past decades, there is still limited knowledge of their precise functions and disease implications. This review focuses on the solute carrier family 41 (SLC41), which consists of three isoforms (A1, A2, and A3) that share homology with the prokaryotic magnesium transporter E (MgtE) Mg²⁺ transporter family. Accumulating evidence has established SLC41A1 as the Na⁺/Mg²⁺ exchanger—a predominant Mg²⁺-efflux system. By contrast, the subcellular site of SLC41A2-mediated Mg²⁺ flux remains undefined, with potential roles at either the plasma membrane or organellar membranes, and SLC41A3 facilitates Na⁺-dependent Mg²⁺ efflux from mitochondria. Additionally, several studies have reported the association between SLC41s and diseases, including Parkinson’s disease, hepatocellular carcinoma, and nephronophthisis-related ciliopathies. By synthesizing current knowledge, this review aims to enhance the understanding of SLC41 transporters in health and disease and to explore their potential as therapeutic targets for clinical intervention. Full article

Gitelman syndrome (GS) is a rare, autosomal recessive salt-losing tubulopathy caused by mutations in the SLC12A3 gene. It involves dysfunction of the sodium-chloride cotransporter positioned on the apical membranes of the distal convoluted tubule cells, causing sodium shortage and mimicking the use of thiazide diuretics. Hyperaldosteronism secondary to sodium depletion and hypovolemia causes hypokalaemia and metabolic alkalosis. This is associated with inhibition of the Transient Receptor Potential Cation Channel, Subfamily M, Member 6 –TRPM6 channel, which leads to urinary magnesium leakage and hypomagnesemia, subsequently stopping PTH secretion and resulting in hypocalcemia and hypocalciuria. Gitelman syndrome frequently presents later in life, as the symptoms are usually not very threatening. However, early identification, diagnosis, and urgent intervention are essential to improve patient prognosis and quality of life. Importantly, both hypomagnesemia and hypokalaemia can impair insulin secretion and sensitivity. Furthermore, hyperaldosteronism caused by the secondary activation of the R-A-A system can also lead to these disorders. Glucose metabolism problems have been shown to prevail amongst GS patients and manifest more frequently in comparison to the general population. When it comes to the treatment used to reduce hyperglycemia in GS-related T2DM, we consider which of the available drugs are the best for those patients. The article analyses the association of Gitelman syndrome with diabetes mellitus based on the available medical literature—as there are no clinical trials or meta-analyses available for this group, it is presented as a narrative review. Full article

Dysregulated magnesium (Mg²⁺) homeostasis contributes to colorectal cancer (CRC), yet its context-dependent function within the tumor microenvironment remains unresolved. This study aimed to determine how sustained low and high extracellular Mg²⁺ environments affect CRC spheroid (SP) growth and Mg²⁺ homeostasis using HT-29 SPs. We analyzed Mg²⁺ flux, the expression of Mg²⁺ transporters (e.g., Transient Receptor Potential Melastatin (TRPM) 6), viability, apoptotic and autophagic markers, and phospho-/oxidoproteomic alterations. Both Mg²⁺ extremes destabilized SP architecture, reduced viability, and induced apoptosis and autophagy, with SPs displaying heightened vulnerability relative to 2D cultures. Mg²⁺ stress impaired Mg²⁺ influx and eliminated adaptive transporter regulation in SPs. Loss of membrane TRPM6/7 heterodimers, driven by altered phosphorylation (e.g., TRPM6 Serine 141, Serine 1252, Threonine 1851) and elevated oxidation (e.g., Methionine 1755), suppressed channel activity. High Mg²⁺ caused profound metabolic failure despite increased total Mg²⁺, reflecting functional Mg²⁺ deficiency. CRC spheroids are acutely susceptible to Mg²⁺ imbalance due to collapsed transporter homeostasis and post-translational inhibition of Mg²⁺ channels. These findings reveal a targetable metabolic vulnerability and support the therapeutic potential of localized Mg²⁺ modulation in CRC. Full article

Magnesium (Mg²⁺) ions require sensitive and selective detection due to their low concentrations and coexistence with similar ions in matrices. This study developed a potentiometric ISE using a new modified polyurethane membrane. The membrane’s negative surface charge facilitates selective interaction with Mg²⁺ ion. Optimal performance was obtained at 0.0061% (w/w) κ-carrageenan and 0.0006% (w/w) D2EHPA. The ISE exhibited a near-Nernstian response of 29.49 ± 0.01 mV/decade across a 10⁻⁹–10⁻⁴ M concentration range (R² = 0.992), with a detection limit of 1.25 × 10⁻¹⁰ M and a response time of 200 s. It remained stable in the pH range 6–8 for one month and demonstrated high selectivity over K⁺, Na⁺, and Ca²⁺ ($K_{ij}$ < 1). The repeatability and reproducibility tests yielded standard deviations of 0.15 and 0.39, while recovery rates confirmed analytical reliability. The water contact angle analysis showed a reduction from ~80° to ~69° after membrane conditioning, indicating increased hydrophilicity and improved interfacial for ion diffusion. FTIR analysis confirmed successful modification by reduced O–H peak intensity, while XRD verified the amorphous structure. SEM revealed a dense top layer with concave morphology, favorable for minimizing leakage and ensuring efficient ion transport within the sensing system. Full article

This work explores water hydrolysis using magnesium as a decentralized dihydrogen source for off-grid households. A dedicated reactor design enabled on-demand dihydrogen generation, coupled with a Proton Exchange Membrane Fuel Cell (PEMFC) for electricity and heat production. Different energy management strategies were compared, highlighting the limitations of single-purpose approaches and the benefits of converting surplus electricity to heat. The integration of photovoltaic generation further reduced magnesium demand by 30%, thus reducing storage requirements to close to 1565 kg of magnesium powder per year, i.e., a volume of 0.9 m³ to cover the heat and electricity needs of a four-person household. Results demonstrate that combining water hydrolysis with magnesium and renewables provides a feasible and sustainable solution for autonomous energy supply in isolated sites. Full article

Orange peel is suitable for reuse due to the quantity and variety of bioactive compounds it contains, such as pectins, sugars and hesperidin. This study designed a scheme for reusing orange peel extract (OPE) using membrane technologies. Initially, a 100 kDa ceramic membrane was used to separate the pectins and hesperidine from acids and sugars and obtain a clarified product. In the subsequent stage, two ultrafiltration membranes of 25 and 5 kDa were tested, improving the results in terms of product transmittance and obtaining permeates whose physical–chemical parameters are compatible with those established by the European Fruit Juice Association. These membranes did not achieve complete separation of monosaccharide sugars from disaccharides. Finally, a 200 Da nanofiltration membrane was used, which completely reduced the sucrose and pectin content, concentrating glucose and fructose by 40%, values higher than those obtained with the GR90PP membrane. In addition, calcium and magnesium ions were completely rejected. Color changes in the permeate and concentrate streams could be appreciated due to the high concentration produced when working in batches. The nanofiltration (NF) process obtained lower yields (approximately 30%) compared to ultrafiltration (approximately 85%). Full article

It is well known that elevated phosphate concentrations in water bodies trigger the eutrophication process, posing adverse environmental, health, and economic consequences that necessitate effective removal solutions. Phosphate removal has therefore been widely studied using various methods, including chemical precipitation, membrane filtration, and crystallisation. However, most of these methods are often expensive or inefficient for low phosphate concentrations. Therefore, in this study, an eco-friendly, sustainable and biodegradable adsorbent was manufactured by extracting calcium ions from an industrial by-product, ground granulated blast furnace slag (GGBS) and magnesium ions from magnesium dross (MgD), then immobilising them on sodium alginate to form Ca-Mg-SA beads. The new adsorbent was applied to remove phosphate from water under different flow patterns (batch and continuous flow), initial pH levels, contact times, agitation speeds and adsorbent doses. Additionally, the degradation time of the new adsorbent, recycling potential, its morphology, formation of functional groups and chemical composition were investigated. The results obtained from batch experiments demonstrated that the new adsorbent achieved 90.2% phosphate removal efficiency from a 10 mg/L initial concentration, with a maximum adsorption capacity of 1.75 mg P/g at an initial pH of 7, a contact time of 120 min, an agitation speed of 200 rpm and an adsorbent dose of 1.25 g/50 mL. The column experiments demonstrated a 0.82 mg P/g removal capacity under the same optimal conditions as the batch experiments. The findings also showed that the adsorption process fitted well to the Freundlich and Langmuir isotherm models and followed a pseudo-second-order kinetic model. Characterisation of Ca-Mg-SA beads using EDX, SEM and FTIR confirmed successful ion immobilisation and phosphate adsorption. Furthermore, the beads fully biodegraded in soil within 75 days and demonstrated potential recycling as a fertiliser. Full article

(1) Background: Repeated planting cycles and monoculture practices have led to widespread magnesium (Mg) deficiency in Chinese fir (Cunninghamia lanceolata) plantations. To gain clarity on how different Mg concentrations affect seedling growth and physiology, we designed the following experiment. (2) Methods: One-year-old seedlings were exposed to three Mg concentration treatments: High (HM), Medium (MM), and Low (LM). Their responses were evaluated in terms of growth traits, photosynthetic activity, and chloroplast structure. (3) Results: Both HM and LM significantly affected leaf development, with LM having the strongest impact. LM disrupted chloroplast structure, causing thylakoid membrane rupture, mitochondrial damage, accumulation of osmiophilic granules, and increased spacing between chloroplasts and cell walls. LM also impaired photosynthesis, lowering the net photosynthetic rate (Pn) and peroxidase (POD) activity, while increasing malondialdehyde (MDA) levels. Leaf growth was reduced, as shown by smaller leaf area and lower biomass. In contrast, HM temporarily enhanced some physiological traits, including intercellular CO₂ concentration (Ci), transpiration rate (Tr), leaf dry matter content (LDMC), and ATPase activity, though it also reduced Fv/Fo compared to MM. (4) Conclusions: Both high and low Mg concentration negatively affected photosynthesis, with Mg deficiency causing the most severe damage. These findings highlight the importance of managing soil Mg levels to maintain healthy growth and productivity in C. lanceolata plantations. Full article