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Genome-wide identification of the Glutathione Peroxidase (GPX) gene family in Taxodium distichum and functional characterization of TdGPX9 in enhancing salt tolerance.

This study systematically identified 10 TdGPX genes in Taxodium distichum, demonstrating that the nucleocytoplasmic-localized TdGPX9 plays a pivotal role in salt stress response. Overexpression of TdGPX9 significantly enhances salt tolerance by strengthening the antioxidant defense system and improving root system plasticity under stress. Taxodium distichum is a premier coniferous species renowned for its exceptional waterlogging and salinity tolerance, serving as a vital forest resource for coastal afforestation and wetland ecological restoration. Within the physiological framework of plant stress resistance, the glutathione peroxidase (GPX) family represents a cornerstone of the antioxidant enzymatic system, playing a critical role in scavenging reactive oxygen species and maintaining cellular redox homeostasis. In this study, 10 TdGPX genes were identified via a comprehensive genome-wide analysis and mapped across eight chromosomes. These genes possess a highly conserved Thioredoxin_like domain, with structural and motif analyses revealing a well-maintained arrangement of conserved motifs within each subgroup. The promoter analysis identified a sophisticated regulatory network enriched with cis-acting elements responsive to light, phytohormones, and abiotic stresses, suggesting their integration into diverse signaling pathways. Expression profiling across various tissues and embryonic developmental stages further highlighted the versatile roles of TdGPX members in plant growth and organogenesis. Notably, qRT-PCR analysis identified the nucleocytoplasmic-localized TdGPX9 as a primary respondent to salinity. Functional validation demonstrated that TdGPX9 overexpression significantly enhances salt tolerance in transgenic Arabidopsis and T. distichum callus by strengthening the antioxidant defense system. Furthermore, TdGPX9 promoted root system plasticity under stress, as evidenced by increased lateral root density. These findings provide a systematic basis for understanding the redox-regulatory mechanisms in baldcypress and offer vital genetic resources for improving forest resilience in coastal wetland ecosystems.

Salt Tolerance

Polymorphonuclear leukocyte bactericidal activity and oxidative metabolism during glutathione peroxidase deficiency.

Glutathione peroxidase (GPx) deficiency has been proposed as a cause of some instances of chronic granulomatous disease (CGD). GPx activity varies greatly among species, and specific deficiency of this selenium-dependent enzyme can be produced by dietary selenium deficiency in rats. Bactericidal activity of polymorphonuclear (PMN) leukocytes from normal rats, humans, and guinea pigs (GPx high, intermediate, and nearly absent, respectively), selenium-deficient rats (GPx absent), and a patient with CGD were compared. There was no correlation between natural levels of GPx and bactericidal activity; only CGD was associated with inability to kill a Proteus mirabilis strain in vitro (killing known to be dependent on oxidative mechanisms). Postphagocytic metabolism was examined in normal and GPx-deficient rats. Both demonstrated normal iodination and superoxide production during phagocytosis and gave similar histochemical reduction of nitroblue tetrazolium dye under either resting or endotoxin-stimulation conditions. Postphagocytic hexose monophosphate shunt activity was somewhat lower in PMN from GPx-deficient animals as compared with normal but was substantially (10-fold) higher than that observed in resting cells. Thus, postphagocytic oxidative responses and subsequent bactericidal activity of PMN leukocytes were not compromised by complete absence of GPx, even in the species with the highest natural level of this enzyme. These results are not compatible with the hypothesis that CGD can be caused by a deficiency of GPx.

Animals

Superoxide dismutase and glutathione peroxidase in polymorphonuclear leucocytes.

Superoxide dismutase (SOD) and glutathione peroxidase (GPX) protect aerobic organisms against the toxic superoxide anion and hydrogen peroxide, which are generated during phagocytosis by polymorphonuclear leucocytes (PMNs). PMNs of children with bacterial infections and with infectious hepatitis contained significantly elevated SOD activity, whereas GPX activity remained in the normal range. In contrast, PMNs of children with viral infections and rheumatoid arthritis exhibited a decreased SOD activity, while GPX activity was again unchanged. The children's age, sex or treatment did not effect the enzyme activities in PMNs. Since SOD generates bactericidal hydrogen peroxide and regulates the release of the toxic superoxide radical into the surrounding tissues, this study may add new understanding to the pathophysiological aspects of acute and chronic inflammatory processes.

Age Factors

Human lysosomal genes: arylsulfatase A and beta-galactosidase.

The segregation of human lysosomal arylsulfatase A (ARS-A) has been evaluated in 50 primary hybrid clones derived from four separate fusions involving WBCs from two unrelated individuals and three hamster cell lines. ARS-A was expressed in the hybrids as a dimeric molecule of very similar or identical subunits. The expression of this enzyme was concordant with that of mitochondrial aconitase (ACON-M), an isozyme assigned to chromosome 22, in all 50 clones and with chromosome 22 segregation in all but one of the 29 karyotyped hybrids. No other human chromosome cosegregated with 22 in these clones, suggesting that this enzyme is specified in hybrid cells by a locus (or loci) on a single chromosome. beta-Galactosidase (B-GAL) expression was analyzed with two different electrophoresis systems and with a number of cell extract preparation methods in 39 of the primary hybrid clones. The B-GAL isozyme expressed in these hybrid cells was concordant with the expression of glutathione peroxidase-1 (GPX-1), an isozyme assigned to chromosome 3, in all 39 clones and with the segregation of this chromosome in 97% of the 29 karyotyped hybrids. These observations substantiate the prior tentative assignments of an ARS-A locus to chromosome 22 and a B-GAL locus to chromosome 3 (Bruns et al., 1978a, b). The implications of the chromosome assignments of loci for 12 human lysosomal enzymes for the cellular assembly of these organelles are discussed.

Aconitate Hydratase

Mapping the covalent cysteine interactome of Ebselen reveals high-sensitivity target engagement and redox proteome remodeling.

Ebselen is a covalent organoselenium compound with broad pharmacological activity, yet its cellular cysteine targets and downstream proteomic consequences remain incompletely defined. Here, we integrated competitive gel-based activity-based protein profiling, reactivity-dependent tandem orthogonal proteolysis-activity-based protein profiling, and TMT-based quantitative proteomics to map Ebselen-induced cysteine engagement and proteome remodeling in living cancer cells. Ebselen exhibited dose-dependent cytotoxicity and markedly perturbed intracellular thiol-redox balance, as reflected by glutathione depletion and altered reactive oxygen species-associated fluorescence readouts. Competitive gel-based profiling confirmed concentration-dependent engagement of protein cysteine residues in live cells. Quantitative rdTOP-ABPP further identified hundreds of dose-responsive cysteine sites in HeLa and HepG2 cells and revealed a preference for cysteine microenvironments enriched with basic residues. Cross-cell-line comparison highlighted CDK5 Cys53, SMU1 Cys298, and RPSA2 Cys163 as conserved covalent nodes, among which CDK5 Cys53 showed high sensitivity to Ebselen treatment, a finding validated by competitive labeling and MS-based site assignment. Global TMT proteomics revealed extensive remodeling of redox-related and cell-survival-associated pathways, including compensatory upregulation of selenoproteins such as TXNRD1 and GPX family members. Together, these results define a chemical proteomic atlas of Ebselen-cysteine interactions and provide a framework for understanding and optimizing covalent organoselenium therapeutics.

Humans

Comparative assessment of post-transport disease susceptibility in Asian seabass (Lates calcarifer): Associations with oxidative stress, immune responses, gut microbiota, and tissue pathology.

Stress is a crucial factor that affects aquaculture systems, particularly during transportation, which often leads to deteriorated fish health and reduced survival rates. This study aimed to investigate the comparative differences in physiological changes, oxidative stress parameters, and immune responses between clinically healthy and diseased Asian seabass (Lates calcarifer) following commercial transportation. The study compared the health status of fish after transportation, categorized into healthy (Healthy) and diseased (Disease) groups. Assessments were conducted on oxidative stress parameters, immune responses, gut microbiota composition, and tissue pathology. The results showed that diseased fish exhibited significantly higher oxidative stress levels (P&#xa0;<&#xa0;0.05), as indicated by an increase in malondialdehyde (MDA) levels and altered antioxidant and redox-related markers, including superoxide dismutase (SOD), nitric oxide (NO), catalase (CAT), glutathione (GSH), glutathione reductase (GR), and glutathione peroxidase (GPx), measured across multiple target tissues (head kidney, gills, liver, intestine, and brain), compared with healthy fish. Furthermore, the expression of immune-related genes was significantly downregulated in diseased fish after transportation, indicating immune suppression. In contrast, healthy fish maintained a more balanced immune response, which may partially mitigate the adverse effects of transport-induced stress. Gut microbiota analysis revealed that diseased fish had a significant reduction in beneficial bacteria such as Cetobacterium somerae and Bacillus spp., accompanied by a significant (P&#xa0;<&#xa0;0.05) increase in opportunistic pathogens including Aeromonas spp., Photobacterium spp., and Vibrio spp. Histopathological examination showed severe damage in the gills, liver, and intestines of diseased fish (P&#xa0;<&#xa0;0.05), while only minor tissue alterations were observed in healthy fish. Overall, the findings indicate that post-transport diseased Asian seabass exhibit marked oxidative stress, impaired antioxidant defense, altered immune responses, gut microbial dysbiosis, and multi-organ tissue damage compared with clinically healthy post-transport fish. These results suggest that deterioration of transport conditions may contribute to post-transport morbidity and disease susceptibility.

Animals

Chronic heart failure and GPX3 promoter methylation: A clinical-epigenetic analysis.

BACKGROUND: Selenoprotein GPX3 is linked to Chronic Heart Failure (CHF), but its promoter methylation patterns in CHF remain unclear. OBJECTIVE: To explore CpG methylation in the GPX3 promoter region and its association with clinical parameters in CHF. METHODS: Twenty CHF patients and twenty healthy controls were included. Methylation levels of CpG sites within the GPX3_FA28 promoter region were quantified. Group differences were assessed using appropriate statistical tests. Restricted cubic spline (RCS) models were applied to explore dose-response associations between differentially methylated CpG sites and clinical indicators across multiple physiological systems. RESULTS: Significant locus-specific methylation alterations were identified in CHF patients. CpG_5 showed hypermethylation (P = 0.017), while CpG_9 (P = 0.045) and CpG_19 (P = 0.008) were hypomethylated compared with controls. Patients with NYHA class I/II exhibited higher methylation at CpG_1 (P = 0.028) and CpG_2 (P = 0.040). CpG_5 methylation displayed nonlinear associations (P < 0.05) with total bilirubin (inverted U-shape), carbon dioxide (triphasic), total cholesterol (U-shape), and plateletcrit (wave-like). CpG_9 correlated with activated partial thromboplastin time and hematopoietic markers, while CpG_19 was linked to eosinophil percentage and erythrocyte parameters. CONCLUSIONS: GPX3 promoter methylation displays apparent locus specificity in CHF. Different CpG sites may contribute to CHF pathophysiology through distinct epigenetic mechanisms. These findings highlight the potential of GPX3 methylation as a stratified biomarker in CHF.

Humans