Search Results (594)

Background and Objectives: The objective of this study is to evaluate whether deferoxamine modulates cell biological properties, such as proliferation and wound closure of porcine corneal endothelial cells (CECs) in vitro, and whether the treatment of CECs with deferoxamine results in an enhanced expression of vascular endothelial growth factor (VEGF). Materials and Methods: Corneal endothelial cells were extracted from porcine globes within 24 h postmortem. Immunohistochemistry for the endothelial Na⁺/K⁺-ATPase was performed to confirm the cells’ endothelial origin. To assess CEC viability and proliferation, a water-soluble tetrazolium salt (WST-1) and 5-bromo-2′-deoxyuridine (BrdU) assay were performed. Corneal endothelial wound closure was evaluated using a wound closure assay. VEGF mRNA expression was evaluated using real-time polymerase chain reaction (rt-PCR). Results: The extracted corneal endothelial cells showed a typical hexagonal morphology with Na⁺/K⁺-ATPase staining of the cell membrane. The treatment with 200 µM deferoxamine significantly increased CEC viability to 121 ± 24% compared to the control group (p = 0.0024). Corneal endothelial cell proliferation did not show any significant changes under the treatment with deferoxamine (p > 0.05). Both 100 µM and 200 µM deferoxamine led to a significantly smaller remaining wound area of 82.4 ± 6.7% and 78.7 ± 6.2% (p < 0.0001) in comparison to the control group after 24 h of treatment in the wound closure assay. Treatment with 200 µM deferoxamine significantly induced VEGF mRNA expression to 1.67- ± 0.57-fold from 1.00- ± 0.03-fold in the control group (p = 0.0006). Conclusions: Deferoxamine effectively enhances corneal endothelial cell viability and wound healing associated with an overexpression of VEGF. Thus, deferoxamine is a potent modulator of cell biological properties of corneal endothelial cells and maintains their integrity in vitro. Full article

To address cryodamage in Culter alburnus sperm, this study evaluated the effects of trehalose supplementation in a conventional cryomedium (D-15 + 10% ethylene glycol). Six experimental groups were established: fresh sperm (G1), a conventional cryomedium (G2), groups supplemented with 10, 100, or 200 mmol/L trehalose (G3–G5), and a control group with extender only (G6). The group with 100 mmol/L trehalose (G4) was associated with improved post-thaw motility parameters (activation rate, movement time, and lifespan) and higher antioxidant (superoxide dismutase and catalase) and energy metabolism (ATPase, succinate dehydrogenase, lactate dehydrogenase) enzyme activities. Ultrastructural damage in G4 included partial plasma membrane rupture and mitochondrial swelling, while G6 exhibited additional damage features including membrane disintegration, mitochondrial disruption, and flagellar fracture. Proteomic analysis revealed that, compared to G1, G4 exhibited higher abundance of proteins (e.g., Histone H2A, cytochrome c oxidase, profilin) involved in structural integrity and energy homeostasis, whereas G6 showed signatures of oxidative stress and metabolic dysfunction (lower abundance of NADH dehydrogenase and higher abundance of calcium-transporting ATPase and glutathione S-transferase). In conclusion, 100 mmol/L trehalose was associated with improved cryopreservation outcomes, and the proteins identified provide a basis for further investigation. This approach offers a framework for refining germplasm conservation strategies in aquaculture. Full article

This study explored the physiological responses and gene expression profiles of the Manila clam (Ruditapes philippinarum) and the hard clam (Mercenaria mercenaria) under heat and hyposaline stress. Experimental conditions involved increasing the temperature from 25 °C to 35 °C and decreasing salinity from 25 ppt to 15 ppt over a 6 h acclimation period, followed by 72 h exposure. Key physiological and immune indicators, including filtration rate, oxygen consumption rate, ammonia excretion rate, and the expression of related genes, were measured. Under heat stress, R. philippinarum exhibited higher filtration, oxygen consumption, and ammonia excretion rates than M. mercenaria at most sampling time points. The expression of fatty acid desaturase (Δ6FAD) and heat shock protein (HSP70) genes increased and then decreased for both species, whereas superoxide dismutase (Cu/Zn SOD) gene expression gradually decreased over time. Furthermore, the expression levels of all three genes were generally significantly higher in M. mercenaria compared to R. philippinarum. Under hyposaline stress, R. philippinarum exhibited significantly higher filtration, oxygen consumption, and ammonia excretion rates than M. mercenaria between 24 h and 72 h. Expression levels of the Na⁺-K⁺-ATPase (NKAα), HSP70, and Cu/Zn SOD genes remained higher in M. mercenaria compared to R. philippinarum. Overall, the present study indicates that M. mercenaria maintains relative stability and R. philippinarum exhibits greater physiological fluctuation under both heat and hyposaline stress. This study highlights bivalve species-specific responses to environmental stressors and provides valuable insights for aquaculture planning and ecological management in different environmental regions, particularly in the context of global climate change. Full article

High ammonia nitrogen stress significantly compromises the survival of Litopenaeus vannamei under low-salinity conditions. However, existing studies predominantly focus on ammonia nitrogen responses under single stressors or normal seawater salinity. The molecular regulatory mechanisms, metabolic remodeling patterns, and key pathway interactions in shrimp subjected to high ammonia nitrogen stress under low-salinity environment remain unclear. In this study, we employed integrated transcriptomic and metabolomic analyses to unveil the underlying molecular responses and metabolic biomarkers in the gills of L. vannamei to ammonia stress under low-salinity conditions. First, L. vannamei underwent low-salinity acclimation from 30‰ to 5‰ salinity and was then reared for one week to acclimate to the experimental environment. Subsequently, shrimp were treated with 42.32 mg/L ammonia nitrogen for a consecutive 96 h period. Integrated transcriptomic and metabolomic analyses elucidated the stress response patterns in the gills of L. vannamei under low-salinity ammonia nitrogen exposure. Specifically, 352, 802, and 140 differentially expressed genes (DEGs) were identified at 12 h, 48 h, and 96 h post-exposure, respectively. GO and KEGG enrichment analyses revealed that the significant DEGs were primarily enriched in six major pathways: autophagy, immune-related pathway, ABC transporter, fatty acid degradation and metabolism, metabolic pathway, and PPAR signaling pathway. Metabolomic profiling identified numerous differentially accumulated metabolites (DAMs) in both positive and negative ion modes, with significantly altered DAMs mainly consisting of organic acids and their derivatives, phospholipids, and other related metabolites. Key DAMs included taurine, guanosine, 1-palmitoyl-sn-glycero-3-phosphocholine, pseudouridine, and betaine. Integrative multi-omics analysis revealed that L. vannamei mediates stress responses by modulating five core pathways under low-salinity/high-ammonia-nitrogen dual stress: fatty acid degradation and metabolism (e.g., acyl-CoA dehydrogenase short chain (Acads), acetyl-CoA acetyltransferase 2 (ACAT2)), autophagy (e.g., autophagy-related protein 101-like (atg101)), immune regulation pathway (e.g., V-type proton ATPase subunit H-like (VhaSFD), actin-5C-like (Act5C)), metabolic pathway (e.g., molybdopterin synthase catalytic subunit-like (Mocs2B), cytochrome P450 2U1-like (Cyp2b1)), and ABC transporter (e.g., ATP-binding cassette sub-family D member 3-like (ABCD3), ATP-binding cassette sub-family B member 10 (ABCB10)). Through characterization of these core pathways, this study reveals the fundamental mechanisms by which L. vannamei responds to high ammonia nitrogen stress following low-salinity acclimation, providing a theoretical foundation for estuarine shrimp farming. Full article

Mycoplasma pneumoniae is a significant pathogen responsible for community-acquired respiratory infections in children and adolescents, with the rising prevalence of macrolide-resistant M. pneumoniae (MRMP), particularly in Asia, presenting critical treatment challenges. Our previous study inferred that a macrolide efflux pump may contribute to macrolide resistance in M. pneumoniae in addition to the common point mutations in 23S rRNA gene. This study aimed to define the specific pump and confirm its role. Through comparative genomic analysis, we identified a candidate gene, MPN_080, encoding an ABC transporter permease, which was further characterized using phylogenetic analysis, AlphaFold-based structural modeling, and biochemical assays. Overexpression of MPN_080 from an erythromycin-resistant isolate in the erythromycin-sensitive M129 resulted in a significant increase in minimum inhibitory concentrations (MICs) from <0.125 µg/mL to 1 µg/mL, while similar overexpression of MPN_080 derived from M129 did not affect MICs. Notably, this resistance mechanism operates independently of M. pneumoniae virulence factors, as evidenced by unaltered colonization capacity in NCI-H292 cells and consistent immune response patterns across both strains. Our findings establish MPN_080 as a novel determinant of macrolide resistance functioning associated with enhanced ATPase activity. These insights into non-classical resistance mechanisms may guide future diagnostic and therapeutic strategies against MRMP. Full article

Normal steps in uptake of non-heme iron by the gastrointestinal tract include ferrireduction and import across the apical enterocyte membrane by divalent metal transporter 1 (DMT1), responsible for the uptake of non-transferrin bound iron (NTBI). This metal import by the intestinal epithelium requires an acidic milieu generated by the proton pump H(+)/K(+) ATPase (ATP4). Gastrointestinal uptake of metal can be affected by altering the acid milieu (e.g., proton pump inhibitors). After metal uptake by enterocytes, ferroxidation and export of the metal by ferroportin (FPN) at the basolateral membrane leads to the export of iron bound to transferrin (Tf). In peripheral tissues, cellular uptake of circulating iron is mediated by receptor-mediated endocytosis of Tf-bound iron, with DMT1 transporting the metal out of the endosomal compartment under acidic conditions generated by the vacuolar H⁺-ATPase. Acidosis is frequently associated with inflammation. The two derangements have relevant consequences like improved solubilization of iron, increased expression of Dmt1, elevated Fe²⁺ uptake due to DMT1’s ability to cotransport H⁺, dissociation of Fe-Tf and hepcidin decreasing Fe export via FPN. These changes result in intracellular iron sequestration that frequently becomes noxious. Pharmacological strategies to inhibit NTBI transport are proposed to protect against iron overload associated with acidosis and inflammation. Full article

Salt stress severely restricts grape (Vitis vinifera L.) production. Serine/arginine-rich (SR) proteins, as a class of RNA-binding proteins, play important roles in plant growth, development and stress responses. However, the function and regulatory mechanism of VvSR34a in grape salt tolerance remain unclear. In this study, grape callus and cutting seedlings were used as materials to explore the role and molecular mechanism of VvSR34a in grape salt stress response. The results showed that, under 100 mM NaCl treatment, the relative level of VvSR34a in grape callus exhibited a ‘first increase and then decrease’ pattern, reaching a peak at 2 h, and the gene was localized in the nucleus. Transgenic experiments confirmed that the overexpression of VvSR34a significantly enhanced salt tolerance in grape callus and cuttings, as evidenced by better growth status, higher chlorophyll content and root activity, as well as lower electrolyte leakage and malondialdehyde (MDA) content under salt stress. In contrast, the silencing of VvSR34a significantly increased salt sensitivity in grapes. Y2H and LCI assays verified that VvSR34a physically interacts with VvCOP9. VvCOP9 may play a negative regulatory role in the salt stress response of the grapevine, and through the loss of the high salt-tolerant phenotype in the VvSR34a/VvCOP9-RNAi lines, it demonstrated that VvCOP9 is genetically upstream of VvSR34a. Furthermore, the ubiquitination and degradation assay demonstrated that VvCOP9 can significantly promote the degradation of VvSR34a. RNA-seq analysis showed that a total of 2834 differentially expressed genes and 202 alternative splicing events were detected in VvSR34a overexpression lines. These differentially expressed genes were significantly enriched in ATPase activity, redox and hormone signaling pathways. This study demonstrates that VvSR34a positively regulates salt tolerance in grapes, providing an important theoretical basis for molecular breeding of salt-tolerant grapevines. Full article

Background: Protein phosphatase 2Cs (PP2Cs) constitutes the largest phosphatase family in plants, playing a pivotal role in signal transduction. Within this family, the PP2C.D subfamily exerts significant influence on cell elongation and stress adaptation by mediating the ‘SAUR-PP2C.D-H+-ATPase’ regulatory module in the auxin signaling pathway. In rice, OsPP2C61 is a PP2C member whose molecular features and potential regulatory context remain unclear. Methods: Our study conducted a preliminary characterization of OsPP2C61 through integrated bioinformatics analysis, spatiotemporal expression profiling, and subcellular localization experiments in tobacco leaf cell. Results: OsPP2C61 encodes a 377-amino-acid protein predicted to be hydrophilic, basic, and structurally unstable. Secondary-structure prediction identified three major elements with random coils as the predominant component, whereas 3D modeling indicated alternating α-helices and β-sheets consistent with a canonical PP2C fold. Phylogenetic inference placed OsPP2C61 within the PP2C.D clade and revealed conserved motifs shared with OsPP2C25, OsPP2C28, and OsPP2C39. Promoter analysis showed enrichment of abscisic acid (ABA)- and methyl jasmonate (MeJA)-responsive elements along with multiple stress-related cis-regulatory motifs. Spatiotemporal expression analysis showed that OsPP2C61 is highly expressed in roots. Subcellular localization assays further demonstrated that the OsPP2C61-GFP fusion protein localizes to the nucleus and the plasma membrane when transiently expressed in epidermal cells of Nicotiana benthamiana. Conclusions: This work delivers the first comprehensive characterization of OsPP2C61, establishing a foundation for mechanistic studies and positioning OsPP2C61 as a candidate gene for rice improvement. Full article

Myo-inositol (MI) is recognized as a potential stress regulator capable of alleviating abiotic stress. The objective of this study is to analyze the role of MI in the salt stress response of Daucus carota L. and its potential mechanisms. “Hongxin Qicun” carrot seedlings were subjected to five treatments: control; salt stress (50 mM NaCl); and salt stress combined with 50, 100, or 200 μM of MI. Through an integrated approach combining physiological assays, non-invasive micro-test technology (NMT), and gene expression profiling, we found that salt stress severely inhibited seedling growth, disrupted K⁺/Na⁺ homeostasis, and triggered excessive H₂O₂ accumulation. Exogenous MI application mitigated these salt-induced damages, with 100 μM MI exerting the optimal effect. MI enhanced Na⁺ efflux and reduced K⁺ efflux in carrot roots under salt stress. Inhibitor experiments indicated that MI-promoted Na⁺ efflux relies on active transport via the plasma membrane (PM) Na⁺/H⁺ antiporter system, and qRT-PCR analysis showed that this response was accompanied by the upregulation of DcSOS1. Furthermore, MI contributes to K⁺ homeostasis by synergistically modulating PM H⁺-ATPase and high-affinity potassium transporters. The established proton gradient helps reduce salt-induced K⁺ loss through depolarization-activated potassium channels and non-selective cation channels. MI treatment decreased electrolyte leakage, malondialdehyde content, and H₂O₂ accumulation by enhancing the activities of the plant antioxidant defense system. Meanwhile, MI upregulated the expression of myo-inositol oxygenase (DcMIOXs) genes, which may contribute to osmotic balance maintenance and facilitate ROS scavenging. In conclusion, exogenous MI alleviates salt-induced physiological disorders in Daucus carota L. by coordinately regulating K⁺/Na⁺ and ROS homeostasis, with 100 μM identified as the optimal concentration for this effect. Full article

Repetitive temperature fluctuations during transportation and storage promote ice crystal formation in salmon flesh, leading to protein denaturation, lipid oxidation, and quality loss. Tuna skin, a major by-product of tuna processing, is a potential source of antifreeze peptides (AFPs) but remains underutilized. This study examined the cryoprotective effects of tuna skin-derived AFPs on salmon cubes subjected to repeated freeze–thaw cycles. Cubes treated with AFPs from three groups of protein hydrolysates prepared using trypsin, pepsin, or neutral protease were evaluated for texture, color, water holding capacity (WHC), volatile odor profiles, protein conformation, biochemical indices, and microstructure. AFP treatment improved textural properties, maintained color stability, and reduced thawing, cooking, and centrifugal losses. The neutral protease-treated group exhibited the optimal cryoprotective ability and it also limited aldehyde and sulfide accumulation, preserved the retention rate of α-helix structure at 49% which was higher than 39% in controls, and enhanced Ca²⁺-ATPase activity to 1.75 μmol Pi·mg⁻¹·h⁻¹ with a 45.8% increase compared to controls, and significantly inhibited protein and lipid oxidation. Microstructural analysis showed compact fibers and intact sarcolemma in the neutral protease-treated group samples, contrasting with severe disruption in controls. This study showed that tuna skin AFPs mitigate freeze–thaw damage in salmon cubes by stabilizing proteins and reducing oxidative deterioration, highlighting their potential as natural, healthy cryoprotectants for seafood preservation, meeting the growing demand of the food industry for clean-label, low-calorie preservation solutions, while advancing the circular economy of aquatic processing via the valorization of tuna skin by-products for high-value seafood applications. Full article

The neuromuscular junction (NMJ) is responsible for transmitting neural signals that trigger muscle contraction. Muscle injuries cause damage to cellular structures and trigger local inflammatory processes. In this context, eccentric contraction was used as an experimental model because it involves excessive stretching, generating mechanical stress. Twenty-five adult male Wistar rats were distributed into groups: Control (C) (n = 5) and Injury (I) (n = 20). The protocol was performed on a treadmill and consisted of 18 sets/5 min/16 m/min speed, with intervals, and with a negative incline (−16º). The analyses consisted of histochemical techniques, such as myofibrillar ATPase and immunofluorescence (calcium channels, synaptophysin and α-bungarotoxin). Group I-0H showed alterations in the presynaptic region and an increase in Type I fibers. I-24H presented disorganization in the postsynaptic region. In I-4D, we observed the reorganization of neuromuscular activity, while I-7D presented greater density and cross-sectional area (CSA) of Type II fibers. It is concluded that the protocol promotes changes in NMJ structure and fiber distribution, mainly in I-24H. In I-4d, a reorganization of neuromuscular activity is observed, and in I-7D, a structural indicator consistent with recovery demonstrates the skeletal muscle’s ability to adapt to injury. Full article

Micropropagated plantlets, after removal from controlled laboratory conditions, require an acclimatization period. Adaptation to the new environment induces anatomical and physiological changes controlled by cellular processes. This study investigated the involvement of the primary proton transport systems of total membranes in pineapple root colonization by diazotrophic bacteria and in the development of plantlets treated with different nitrogen doses, allowing an understanding of nutrient absorption and accumulation dynamics. The experiment followed a randomized block design (RBD) in a factorial scheme (2 × 3 × 2), with two inocula (a mixture of diazotrophic bacteria containing Burkholderia sp. UENF 114111, Burkholderia silvatlantica UENF 117111, and Herbaspirillum seropedicae HRC 54, and another without bacteria), three urea doses (0, 5, and 10 g L⁻¹), and two evaluation (90 and 150 days) and bacterial counting times (30 and 150 days), with three blocks. Diazotrophic bacterial populations were lower in older plantlets. H⁺ transport mediated by P H⁺-ATPases changed with acclimatization time. Inoculation did not induce transport; however, the F_max of V H⁺-ATPase was lower without nitrogen fertilization. Nitrogen fertilization affected V H⁺-ATPase proton transport activity in root membranes. The presence of diazotrophic bacteria did not induce proton transport. On the other hand, nitrogen fertilization and acclimatization time affected the proton transport activity mediated by H⁺-ATPases isolated from roots of micropropagated pineapple. Full article

The order Herpesvirales contains three families, Orthoherpesviridae, Alloherpesviridae, and Malacoherpesviridae. The time since divergence of families from the common ancestor makes protein primary sequence comparison an insensitive tool for identifying common genes. Comparison of three-dimensional protein structures can reveal similarities that are not evident in primary sequences. Salmonid herpesvirus 1 (SalHV-1) is an alloherpesvirus. Complete sequencing of SalHV-1 VR-868 strain Winthrop by a combination of short- and long-read methods revealed 120 putative open reading frames (ORFs). BLAST search for similar protein sequences discovered five ORFs that encoded proteins with homologs in the orthoherpesviruses, including the major capsid protein, capsid triplex subunit 2, the catalytic subunit of the DNA polymerase, the helicase subunit of the helicase/primase complex, and the terminase ATPase subunit. An annotation of the ORFs of SalHV-1 was performed in which ORFs of SalHV-1 were modeled using AlphaFold3, and the models were used as prompts for structural similarity search using DALI and FoldSeek. Completion of this search strategy for the entire genome expanded the set of genes shared among the Herpesvirales to include additional proteins related to DNA replication and genome integrity, capsid assembly and genome packaging, and capsid nuclear egress. No homologs for any tegument proteins or proteins of the conserved entry apparatus of the Herpesviridae (gB, gH or gL) were discovered. Full article

A decrease in pH can affect the biochemical properties of a sulfate reduction system, but the stress responses to such pH fluctuations and acid-adaptive mechanisms of the microorganisms remain incompletely understood. Here, we compared the sulfate (SO₄²⁻) reduction performance of a sulfate-reducing consortium (SRB system) and a pure Desulfovibrio sp. system (Des. system, control) under pH 7.0, 5.5, and 5.0 via batch experiments. A key novelty is the integration of microbial physiology and metagenomics to reveal adaptive mechanisms: the Des. system showed significant inhibition of growth and sulfate reduction with decreasing pH, while the SRB system maintained superior SO₄²⁻ removal efficiency through three synergistic adjustments: (1) physiological regulation (enhanced H⁺-ATPase activity, stress protein production, and cell membrane cyclopropane fatty acid content); (2) microbial community restructuring (enrichment of acid-resistant Bacillus and Clostridium); and (3) functional gene upregulation (sulfate import, dissimilar sulfate reduction, sulfide oxidation, and SO_x system-related genes, p < 0.05). This study links physiological responses to metagenomic functional shifts under acid stress, providing critical theoretical support for applying sulfate-reducing consortia in acidic sulfate-containing wastewater remediation. Full article

Postharvest autolysis severely compromises the commercial value of fresh Dictyophora rubrovolvata. This study integrated physiological, ultrastructural, and metabolomic analyses to elucidate the underlying mechanism. Results indicated a continuous decline in cellular adenosine triphosphate levels during storage, leading to an energy crisis and triggering cellular stress responses. Metabolomic analysis revealed that the fruiting bodies activate pathways such as glycolysis and the pentose phosphate pathway through metabolic reprogramming to maintain homeostasis. However, the intensifying energy crisis inhibited Calcium ion ATPase activity, disrupting ion homeostasis and leading to Ca²⁺ influx. This activated phospholipases and initiated membrane lipid degradation, accompanied by a burst of reactive oxygen species and elevated levels of H₂O₂ and malondialdehyde, creating a vicious cycle of oxidative stress. Concurrently, cell wall components (chitin, β-1,3-glucan, cellulose) are accelerated in degradation due to the upregulation of corresponding hydrolases. Transmission electron microscopy confirmed progressive disintegration of cellular structures, including mitochondria, the plasma membrane, and the cell wall. These findings establish an “energy-membrane lipid-cell wall” cascade framework, revealing that D. rubrovolvata autolysis is an active, orderly form of programmed cell death under energy stress. This study provides new insights into the physiological mechanisms of postharvest quality deterioration in edible fungi. Full article