Search Results (4,669)

In recent years, a novel class of highly stable multiprotein complexes, with molecular masses ranging from 1 to 2 MDa, has been identified in human milk, placenta, sea urchin eggs, and sea cucumbers. These complexes exhibit extraordinary stability, dissociating only under stringent conditions involving 8 M urea, 3 M MgCl₂, EDTA, and DTT. Previous investigations have demonstrated that complexes derived from different organs of the sea cucumber Paracaudina chilensis differ in size, molecular mass, and protein/peptide composition; however, their enzymatic activities have remained unexplored. In the present work, we performed the first systematic analysis of phosphatase activity associated with highly stable complexes isolated from five organs of P. chilensis: the body wall, gonads, respiratory trees, intestine, and coelomic fluid. Complexes were purified via gel filtration chromatography on Sepharose 4B, followed by ultracentrifugation. Phosphatase activity was determined spectrophotometrically by monitoring the hydrolysis of p-nitrophenyl phosphate. Our results indicate that all five complexes harbor phosphatases with optimal pH values spanning 7.0 to 10.0. Alkaline phosphatases (pH 9.0–10.0) displayed pronounced organ specificity: maximal activity was observed in the intestinal complex, whereas minimal activity was detected in the gonadal complex. Phosphatase activity in complexes from the body wall and respiratory trees exhibited a bell-shaped dependence on Mg²⁺ concentration, with optima at 5 mM and 1 mM, respectively; in contrast, activity in the intestinal and coelomic fluid complexes increased to a plateau at 5–10 mM Mg²⁺. Ca²⁺ ions predominantly inhibited activity, with the notable exception of the intestinal complex, where they exerted no effect on hydrolysis. EDTA treatment resulted in complete inactivation of the enzymes in most complexes; however, intestinal activity was retained at 50% even at high chelator concentrations, suggesting the presence of a metal-independent phosphatase. Collectively, these data indicate that the stable multiprotein complexes of P. chilensis contain an organ-specific repertoire of phosphatases that differ in pH optimum, metal ion dependence, and inhibitor sensitivity. These findings open new avenues for understanding the roles of such complexes in organ-specific physiological functions and regenerative mechanisms in echinoderms. Full article

Marine-derived bioactive compounds have attracted considerable attention as functional ingredients for food and nutraceutical applications due to their various biological activities. Among marine resources, macroalgae represent a sustainable and abundant source of structurally diverse bioactive compounds, including polyphenols, pigments, and polysaccharides. This review provides a comprehensive overview of macroalgal bioactive compounds, with particular emphasis on their sources, the environmental and seasonal factors influencing their composition, chemical classification and characteristics, extraction technologies, biological properties and food and nutraceutical applications. Particularly, attention is given to the molecular mechanisms underlying their antioxidant and anti-inflammatory effects, including radical scavenging, metal chelation, modulation of endogenous antioxidant defense systems, and regulation of key signaling pathways involved in inflammation. Green extraction techniques and encapsulation strategies for improving the stability, bioavailability, and functionality of macroalgal bioactives are critically discussed. Current applications in foods and nutraceutical products are reviewed alongside the major challenges related to biomass variability, large-scale production, standardization, and regulatory compliance. Overall, macroalgal bioactive compounds represent a promising class of sustainable health-promoting ingredients, and continued advances in cultivation, processing, extraction technologies, formulation, and regulatory frameworks will be essential to support their broader industrial utilization. Full article

Neurogenic bladder is a condition associated with impaired voiding, leading to urinary stasis and increased susceptibility to urinary tract infections, predominantly caused by Escherichia coli. In this context, bacterial iron acquisition systems represent attractive targets for alternative antimicrobial strategies. This study aimed to investigate the interactions of deferoxamine with E. coli iron acquisition proteins, combining an experimental model of neurogenic bladder with molecular analyses. The experimental model of neurogenic bladder was induced by complete spinal cord transection in rats, followed by urine collection by cystocentesis and microbiological characterization of uropathogens. Subsequently, molecular docking and energetic analyses were performed to evaluate the binding of deferoxamine and its Fe-DFO complex to the FhuE receptor of the ferric hydroxamate uptake pathway, with FhuA and FhuD prepared as correlated targets of the same pathway for structural context. The animals presented urinary retention and bacterial colonization, with E. coli identified as the pathogen. The results of the molecular docking revealed geometrically plausible accommodation of Fe-DFO within siderophore recognition pockets, involving residues associated with siderophore recognition and transport, as well as binding affinity scores consistent with weak-to-moderate structural complementarity compared to reference ligands. It is concluded that the neurogenic bladder model provides a biologically relevant framework for the study of urinary tract infections and that deferoxamine exhibits molecular interactions consistent with the ferric hydroxamate uptake system of E. coli. Because the present analysis was restricted to the Fhu pathway, these findings cannot be extrapolated to overall bacterial iron homeostasis, which involves multiple parallel acquisition systems. The current work is explicitly positioned as a proof-of-concept investigation; in vivo administration of DFO in the neurogenic bladder model, functional assays of iron uptake, transporter specificity experiments, and molecular dynamics analyses are identified as priority directions for future work. Full article

Protein-rich polysaccharides are increasingly recognized as multifunctional biopolymers with significant biomedical potential. In this study, a protein–polysaccharide complex (JrPRP) was isolated for the first time from the root bark of Juglans regia L. and comprehensively characterized. JrPRP was obtained with a yield of 4.7% (w/w) and exhibited an acidic composition enriched in uronic acid-related components, together with minor neutral sugars. Spectroscopic analyses (FTIR and UV–Vis) confirmed the coexistence of carbohydrate and protein domains, while chromatographic profiling (TLC and HPLC) indicated a heterogeneous monosaccharide composition. Scanning electron microscopy revealed a porous and irregular microstructure, consistent with a structured biopolymeric network exhibiting pronounced anionic character. Functionally, JrPRP demonstrated notable antioxidant activity, with IC₅₀ values of 405 ± 1.8 µg/mL (DPPH), 225 ± 3.5 µg/mL (ABTS), and 229 ± 1.7 µg/mL (metal chelation), along with strong ferric-reducing capacity. The complex exhibited antibacterial activity against Pseudomonas aeruginosa, Klebsiella pneumoniae, and Staphylococcus aureus (MIC: 2–9 mg/mL), as well as potent antibiofilm activity, inhibiting up to 94% of Escherichia coli biofilm formation. Biocompatibility assays indicated low hemolytic activity, supporting its favorable safety profile. In addition, JrPRP showed moderate anticoagulant effects and strong anti-inflammatory activity, reaching 98% inhibition of protein denaturation, comparable to or exceeding diclofenac under similar conditions. These findings identify J. regia root bark as a promising and previously underexplored source of structurally distinctive uronic acid-containing protein-rich polysaccharides and provide new insights into the relationship between their compositional features and multifunctional biological activities. Full article

Background: Continuous chelation with etidronic acid (1-Hydroxyethylidene-1,1-diphosphonic acid, HEDP) has been proposed as a less aggressive alternative to sequential irrigation with ethylenediaminetetraacetic acid (EDTA) in endodontics. This systematic review and meta-analysis aimed to compare the effects of these two protocols on the mechanical properties and structure of root dentin. Methods: PubMed, Scopus, and Cochrane Central databases were searched up to June 2026 for in vitro studies comparing continuous chelation (NaOCl + HEDP mixture) with sequential irrigation (NaOCl and EDTA) on root dentin of permanent teeth. Studies on coronal dentin and those not using NaOCl + HEDP as a mixture were excluded. Risk of bias was assessed using the QUIN tool. Meta-analyses were performed for fracture resistance using a random-effects model. This review was registered in PROSPERO (CRD420250630663). Results: Twenty studies with a total of 572 specimens were included. Six studies had a low risk of bias and thirteen had a medium risk. The qualitative synthesis showed that HEDP generally resulted in similar or lower levels of erosion, microhardness reduction, demineralization, and collagen degradation compared to EDTA. The meta-analysis revealed no significant difference in fracture resistance (5 studies; SMD = 0.28; 95% CI: −0.37 to 0.92; p = 0.40); however, substantial heterogeneity was observed (I² = 66.7%). Conclusions: The evidence was limited by substantial heterogeneity and mainly medium risk of bias. Within the limitations, in vitro evidence suggests that continuous chelation with HEDP is comparable to EDTA in terms of root dentin mechanical properties and composition, supporting its use as a chelating agent in endodontic practice. This research received no external funding. Full article

Photodynamic therapy (PDT) is a cornerstone non-invasive modality for keratinocytic precancers and non-melanoma skin cancer (NMSC), leveraging selective photosensitizer accumulation, light activation, and reactive oxygen species (ROS) generation. This narrative review synthesized literature from major databases (2010–2025) to comprehensively evaluate PDT’s molecular mechanisms, innovative optimization protocols, and clinical efficacy across actinic keratosis (AK), field cancerization, Bowen’s disease (BD), basal cell carcinoma (BCC), and invasive squamous cell carcinoma (cSCC). The evidence highlights frontline clinical maturity and excellent cosmetic outcomes for superficial lesions (AK, field cancerization, superficial BCC, and BD), with daylight PDT offering a virtually painless alternative for widespread dysplasia. However, therapeutic reliability decreases in thick nodular, pigmented, or high-risk lesions due to optical barriers and tissue hypoxia. To overcome these limitations, advanced physical and chemical enhancements—such as ablative fractional lasers, iron chelators, epigenetically enhanced PDT (ePDT), and targeted nanocarriers—are actively reshaping drug delivery and cellular susceptibility. Furthermore, cyclic PDT serves as an indispensable tissue-sparing intervention for organ transplant recipients and Gorlin syndrome patients. In conclusion, while PDT is highly effective for superficial neoplasias, precise histopathological stratification and the integration of nanomedicine are critical to overcoming current biological barriers in aggressive dermatological malignancies. Full article

Iron overload is a recognized risk factor for female reproductive dysfunction, yet the underlying cellular and molecular mechanisms remain incompletely understood. In this study, the effects of iron overload on ovarian granulosa cells were investigated, and a protective role of the steroid biosynthesis pathway against ferroptosis was identified. A mouse model of ovarian iron overload was established by daily gavage of ferric citrate (FC, 120 mg/kg for 40 days). Iron-overloaded female mice exhibited disrupted estrous cycles, reduced serum estradiol levels, impaired antral follicle development, and decreased pregnancy rates and litter sizes. Metabolomic analysis of freshly isolated granulosa cells revealed significant depletion of unsaturated glycerophospholipids and fatty acids, along with reduced antioxidants such as glutathione, vitamin E, and coenzyme Q6, and enrichment of the ferroptosis pathway. Transcriptomic analysis showed marked upregulation of genes involved in steroid biosynthesis, including Hmgcr and Fdft1, and their master transcription factor Srebf2. In cultured KK1 granulosa cells, FC treatment increased intracellular Fe²⁺ and reactive oxygen species, decreased glutathione content and NADPH/NADP⁺ ratio, elevated malondialdehyde levels, and induced lipid peroxidation and plasma membrane rupture, all of which were attenuated by the iron chelator deferoxamine. Knockdown of Srebf2 suppressed Hmgcr and Fdft1 expression, exacerbated lipid peroxidation, and increased membrane damage in iron-overloaded cells, confirming that SREBF2-driven steroid biosynthesis acts as an endogenous anti-ferroptotic mechanism. Collectively, these findings demonstrate that iron overload triggers ferroptosis in granulosa cells, leading to follicular arrest and reduced fertility, and that activation of the steroid biosynthesis pathway counteracts ferroptosis, likely through the production of protective intermediates. This study provides a mechanistic basis for iron overload-induced female infertility and identifies the steroid biosynthesis pathway as a potential therapeutic target. Full article

Two different renin isoforms are expressed in extrarenal tissues. The classical renin-a has been associated with detrimental effects, whereas renin-b exerts protective effects during glucose starvation. Glucose starvation selectively increased renin-b mRNA levels. 8Br-cAMP increased renin-a mRNA levels independently of glucose as well as of renin-b in glucose-starved cells. Adenylyl cyclase (AC) stimulation by forskolin increased expression of both renin transcripts, while AC inhibition by SQ22536 produced the opposite effect. PKA inhibition by KT5720 reduced the mRNA levels of both renin transcripts glucose-independently. Forskolin reversed the effect of KT5720 on renin mRNA levels. A23187-mediated increase in [Ca²⁺]i increased renin-b mRNA levels in glucose-starved cells. Ca²⁺ chelator BAPTA decreased renin-a mRNA expression in control cells and renin-b levels glucose-independently. Forskolin reversed the BAPTA-mediated decreases in renin-a but not renin-b expression. While the regulation of renin transcript levels by cAMP and PKA resembled known regulation in the kidney, the effect of intracellular free Ca²⁺ levels were opposite. This supports the existence of a separate renin system in cardiac cells. Full article

This review is devoted to the occurrence, extraction, structural characterization and catalytic applications of vanadyl porphyrins present in heavy crude oils and petroleum residues. Vanadyl porphyrins represent the major vanadium-containing compounds in petroleum systems and play a dual role as both catalyst poisons during refining processes and valuable precursors for functional catalytic materials. Particular attention is devoted to recent advances in extraction technologies, including solvent extraction, ionic liquids, deep eutectic solvents, functionalized adsorbents and chelating agents. Process intensification approaches such as ultrasound- and microwave-assisted extraction, are also discussed as promising strategies for improving extraction efficiency and selectivity. Furthermore, recent developments in petroleum characterization using FTICR-MS, EPR, HYSCORE and LA-ICP-MS techniques are reviewed, providing insights into metalloporphyrin speciation, oxidation states, and distribution within complex petroleum matrices. Beyond their traditional role in catalyst deactivation, vanadyl porphyrins have emerged as attractive precursors for catalytic materials applied in oxidation reactions, photocatalysis, oxidative desulfurization, wastewater treatment and selective organic synthesis. The development of hybrid catalytic systems based on mesoporous silica, graphene oxide, carbon nanotubes, polymer matrices, and metal–organic frameworks has significantly improved catalyst stability, activity and recyclability. Current challenges related to the selective extraction, preservation of metalloporphyrin structure and catalytic performance evaluation are also discussed. Overall, this review provides an integrated perspective on the recovery, characterization and valorization of vanadyl porphyrins for sustainable petroleum upgrading and environmental applications. Full article

TPEN (N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine) is a ligand containing six nitrogen donors. It is characterized by high structural flexibility, enabling the coordination of metals with various ionic radii and coordination numbers. It is an advanced metal chelator that demonstrates high selectivity, particularly towards “soft” and “medium” metal ions, and has a wide range of applications, from coordination chemistry, materials engineering, and nuclear energy to innovations in medicine. TPEN can cross cell membranes freely, which is important in cell biology. However, its presence is not neutral for healthy cells and can lead to apoptosis by depleting essential metals such as zinc, iron, and copper. Targeted delivery systems are therefore essential. This can be achieved, for example, by using nanoparticles that release TPEN upon ultrasound. This review systematizes the understanding of TPEN complexes. Methods for the coordination of various d-, p-, and f-block metals are presented, as well as the properties of these complexes, which are crucial to understanding the mechanisms of reaction with TPEN. This ligand may find applications both as a diagnostic tool (in sensors) and as a therapeutic tool (by inducing cancer cell death). This work also demonstrates the need to design new and more effective TPEN analogs that overcome problems with solubility and stability in acids. Full article

According to the main principles of the circular economy, recovering bioactive compounds from food waste has significant potential to deliver financial, environmental, and health benefits by incorporating them into food products as additives, emulsifiers, antioxidants, and antimicrobial agents to enhance nutritional and functional value and/or extend product shelf life. This work investigated the potential of a food waste material, such as chickpea aquafaba from industrial processing, as a fermentation substrate using promising lactic acid bacteria, including L. plantarum AME-01, L. paracasei CBA L74, and L. mesenteroides, under non-controlled pH conditions, and evaluated the antioxidant/chelating capacity of the postbiotic obtained from the process. Fermented substrates were thermally inactivated to produce postbiotic preparations, which were characterized in terms of inactivated biomass and lactic acid concentration. Subsequently, liquid postbiotics were spray-dried using a lab-scale spray dryer, and the resulting powders were characterized in terms of antioxidant and chelating properties. While the postbiotic preparations using L. paracasei CBA L74 showed significantly lower activity (23.78 ± 7.25%) compared to non-fermented aquafaba (56.85 ± 2.79%), those using L. plantarum AME-01 (84.60 ± 5.57%) and L. mesenteroides (82.56 ± 1.11%) exhibited increased chelating activity. The antioxidant power of all fermented powders was significantly improved, confirming the potential of postbiotic ingredients as stabilizing additives in food formulations. Full article

Red blood cells (RBCs) are the most abundant cells in peripheral blood and perform critical functions including oxygen and carbon dioxide transport, acid base buffering, regulation of hemorheology, and modulation of immune signaling. Due to their high content of hemoglobin and labile iron, prolonged exposure to high oxygen tension, membrane enrichment with polyunsaturated fatty acids, and the absence of both nucleus and mitochondria, mature RBCs have limited capacity for damage repair and protein re-synthesis, making them highly susceptible to attack by reactive oxygen species (ROS) and reactive nitrogen species (RNS). Hydrogen peroxide (H₂O₂) and 2,2′-azobis(2-methylpropionamidine) dihydrochloride (AAPH) are the two most commonly used inducers in the in vitro models of RBC oxidative injury: H₂O₂ primarily generates hydroxyl radicals via hemoglobin/ferrous ion-dependent Fenton reactions, simulating acute oxidative stress. AAPH releases peroxyl radicals upon thermal decomposition, mimicking persistent lipid peroxidation in cell membranes. Curcumin, a representative polyphenolic compound derived from turmeric, exerts multiple effects including free radical scavenging, metal ion chelation, membrane stabilization, anti-inflammatory activity, and regulation of redox homeostasis. This review systematically summarizes the pathological basis of RBC oxidative damage and the protective effects of curcumin on membrane systems, antioxidant defenses, morphology, and function, based on the core evidence chain “H₂O₂/AAPH—RBCs—curcumin”, integrating recent experimental findings on H₂O₂, AAPH, blood storage-induced injury, and curcumin formulations. It emphasizes that mature RBCs lack nuclei and mitochondria, and therefore mechanisms such as Nrf2/ARE signaling, HO-1 induction, mitochondrial apoptosis, caspase cascades, and inflammasome activation should not be directly equated with transcriptional regulatory pathways within mature RBCs, but rather interpreted as indirect evidence originating from nucleated cells, erythroid progenitors, or the blood microenvironment. The article further proposes that future research should focus on standardized RBC models, physiologically relevant dosages, nanodelivery systems, and translational applications in blood storage, to facilitate the transition of curcumin’s in vitro antioxidant evidence into clinical transfusion medicine and precision nutritional interventions. Full article

A novel centrifuge-less cloud-point extraction (CL-CPE) method based on pyrogallol (PG) was developed for the spectrophotometric determination of total vanadium. The method employs a mixed micelle-mediated extraction system comprising the nonionic surfactant Triton X-114 and the ionic liquid Aliquat 336 (A336), which serves as a source of monovalent cations capable of forming an ion pair with the anionic vanadium–PG chelate. The extracted species, (A336⁺)[V^IV(OH)(PG)₂], exhibits several absorption maxima (309, 362, and 436 nm), providing enhanced selectivity through appropriate wavelength selection according to the sample matrix. The principal absorption maximum occurs at 309 nm. At a sevenfold preconcentration factor, the method provides high sensitivity at this wavelength, with a molar absorptivity of 3.2 × 10⁷ L mol⁻¹ cm⁻¹, a limit of detection of 0.11 ng mL⁻¹, and a Sandell sensitivity of 1.6 × 10⁻³ ng cm⁻². The applicability of the method was demonstrated through the analysis of drinking water samples, spent vanadium catalyst materials, and vanadium-containing dietary supplements. The method was further evaluated using the RGBfast model, a white analytical chemistry assessment tool that integrates analytical performance, environmental sustainability, and practical and economic efficiency. The evaluation indicated a high overall whiteness score. Full article

Background/Objectives: The anticoagulant used for blood collection is a fundamental but underexplored variable in platelet-rich plasma (PRP) preparation. Ethylenediaminetetraacetic acid (EDTA) and sodium citrate act on platelets through distinct calcium chelation mechanisms with potentially different consequences for PRP quality. Our group has previously demonstrated that biological and demographic variables independently modulate platelet composition in PRP; the present study extends this analysis to the pre-analytical anticoagulant variable. No prospective paired clinical study has systematically compared the effects of EDTA and sodium citrate on platelet morphological parameters in a real clinical setting. This study aimed to characterise these differences and evaluate their implications for orthobiologic therapy. Methods: A prospective within-subject paired-sample study was conducted at Instituto Cugat—Quirónsalud Barcelona (November 2025–April 2026). Twenty-six consecutive adult patients undergoing routine blood extraction prior to orthopaedic procedures had blood drawn simultaneously into K₂-EDTA and sodium citrate (3.2%) tubes. Full haematological analysis was performed on a Sysmex XN automated analyser within 30 min. Primary outcomes were mean platelet volume (MPV), platelet distribution width (PDW), large platelet ratio (P-LCR), large platelet cell count (P-LCC), and plateletcrit (PCT). Statistical comparisons used the paired t-test or Wilcoxon signed-rank test; effect sizes were quantified as Cohen’s d. Results: Seven of eight platelet-related parameters differed significantly between anticoagulants (all p < 0.001). Compared to sodium citrate, EDTA produced systematically higher MPV (+10.1%, d = 2.81), P-LCR (+25.8%, d = 2.41), P-LCC (+24.3%, d = 1.70), PDW (+13.5%, d = 1.33), PCT (+7.3%, d = 0.78), RDW-CV (+2.0%, d = 0.83), and RDW-SD (+2.6%, d = 0.80). MPV was higher with EDTA in all 26/26 paired samples without exception. Total platelet count did not differ significantly (p = 0.135). Effect sizes for all morphological parameters were large (d ≥ 0.78). Conclusions: EDTA is associated with large, reproducible, and universal platelet morphological changes consistent with calcium chelation-induced artefact, not genuine platelet hypertrophy. These artefactual changes systematically overestimate platelet size and large platelet indices by up to 26%, with direct implications for PRP quality assessment in orthobiologic medicine. Sodium citrate should remain the anticoagulant of choice for PRP preparation. Clinicians using EDTA must recognise that morphological parameters do not reflect functional platelet capacity. Full article

Rice protein peptides, abundant byproducts of rice processing, represent a sustainable source for developing novel nutritional delivery systems. To address the low bioavailability of traditional calcium supplements, this study aimed to fabricate a high-performance calcium-chelating complex (RPP-Ca) and elucidate its functional mechanism. The synthesis process was systematically optimized, yielding a maximum calcium-binding capacity of 93.98 ± 1.99 mg/g under optimal conditions (pH 10, 70 °C, 50 min reaction time, peptide-to-calcium mass ratio of 2:1). Physicochemical characterization utilizing scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) confirmed successful chelation, revealing significant microstructural reorganization and enhanced thermal stability compared to native peptides. Functional validation via in vitro Caco-2 cell models and in vivo calcium-deficient mouse models demonstrated that RPP-Ca significantly promotes intestinal calcium absorption and osteogenesis. Mechanistically, these effects were mediated through the activation of the TRPV6-Calbindin9k signaling axis. These findings underscore the potential of industrial rice protein peptides as an effective and bioavailable calcium fortification ingredient, providing a theoretical basis for the high-value utilization of rice byproducts in functional foods. Full article