Lead (Pb) is a non-essential, highly toxic, and persistent element widely recognised as one of the most concerning pollutants, and it is listed in the Priority List of Hazardous Substances. Widespread environmental contamination from Pb is a serious issue for human health and wildlife. The liver, a key compartment for metal detoxification and excretion, is also the organ in which Pb mainly accumulates in fish. Herein, we investigated for the first time the morphological and functional injuries induced in zebrafish (Danio rerio) liver by two very low and environmentally relevant concentrations of Pb (2.5 and 5 μg/L) after 48, 96, and 192 hours of exposure. We showed significant histological alterations in all the exposed samples, also demonstrating that the extent of injuries increased with dose and exposure time. The most common modifications observed were congestion of blood vessels and sinusoids, cytoplasmic vacuolizations, parenchyma dyschromia, and macrophage proliferation. Pb administration also resulted in a significant increase in lipid content and the upregulation of key genes involved in metal detoxification (mtf1) and the defensive response against oxidative stress (sod1 and cat). We showed that even very low doses of Pb can disrupt liver morphology and function.

It was of great practical significance to repair the toxicity of salt stress environment to soybean seedlings and maintain the balance between agricultural production and ecological environment in the Yellow River valley of China. ‘Xudou 20’ was used as the experimental material, a large-scale planting variety in the old Yellow River basin. Endophytes 131 and 137 isolated from soybean root nodule were taken as the research objects, and the soybean plants were cultivated by pot culture in intelligent artificial incubator. Salt stress group, bacteria suspension group and control group were set up to study the effects of inoculation treatments on the activities of superoxide dismutase (SOD) and catalase (CAT) of soybean seedlings under different NaCl stress. The results showed that when inoculated with endophyte 131 bacterial suspension and cultured for 14 days, the SOD activity was the highest (14.89 U•g−1•FW) at the salt concentration 50 mmol•L-1. When inoculated with 131 bacterial suspension (2:1) and cultured for 28 days, the SOD activity reached the highest (0.94 ug-1FW) at the salt concentration of 50 mmol•L-1, and the CAT activity amounted to the highest (1910 U•g−1•min−1). The 16S rDNA sequencing and phylogenetic analysis showed that the most similar strain of strain 137 was Bacillus cereus, and the most similar strain of strain 131 was Enterobacter ludwigii. Therefore, the activities of SOD and CAT in soybean seedlings inoculated with endophytes 131 and 137 increased at different degrees under salt stress, which could effectively alleviate the damage of salt stress environment to plants, and thus improve the stress resistance of plants.

The emergence of multidrug-resistant pathogens such as Listeria monocytogenes and Shiga toxin-producing Escherichia coli (STEC) poses public health challenges, and this has led to a continuous search for effective novel antimicrobial agents. This study aimed to isolate marine actinomycetes from South Africa, evaluate their in vitro antimicrobial activity against Listeria and STEC, and characterize their mechanisms of action. Marine actinoymcetes were isolated and identified by 16S rRNA sequencing. Gas chromatography-mass spectrometry (GC-MS) was used to identify the chemical constituents of bioactive actinomycetes secondary metabolites. Antibacterial activity of the secondary metabolites was assessed by the broth microdilution method and their mode of actions were predicted using computational docking. While five strains showed antibacterial activity during primary screening, only Nocardiopsis dassonvillei strain SOD(B)ST2SA2 exhibited activity during secondary screening for antibacterial activity. GC-MS identified five major bioactive compounds: 1-octadecene, diethyl phthalate, pentadecanoic acid, 6-octadecenoic acid, and tri-fluoroacetoxy hexadecane. SOD(B)ST2SA2`s extract demonstrated the minimum inhibitory con-centration and minimum bactericidal concentration ranging from 0.78–25 mg/ml and 3.13 to > 25 mg/ml, respectively. Diethyl phthalate displayed the lowest bacterial protein binding energies (kcal/mol): −7.2, dihydrofolate reductase; −6.0, DNA gyrase B, and −5.8, D-alanine:D-alanine lig-ase. Thus, marine N. dassonvillei SOD(B)ST2SA2 is a potentially good source of antibacterial compounds that can be used to control STEC and Listeria monocytogenes.

Abstract: It is assumed that upon SARS-CoV-2 infection granulocytes can undergo potentially destructive oxidative burst. Therefore, the aim of this study was to evaluate some parameters of redox and inflammatory signaling in granulocytes of recovered and of deceased COVID-19 pa-tients. Granulocytes were isolated from the blood of 32 COVID-19 patients on admission to the hospital (16 survived and 16 died within a week). The levels of proteins (immunoassay), eico-sanoids (UPLC-MS) and antioxidants activity (spectrophotometry) were examined. Enhanced activation of Nrf2 and NFκB and the levels of heme oxygenase and proinflammatory cytokines where found in granulocytes of all COVID-19 patients, while Cu,Zn-SOD and Mn-SOD activities were decreased, especially in deceased patients. Moreover, in patients who died increased levels of pro-inflammatory eicosanoids (PGE2 and TXB2) and decreased of anti-inflammatory (15d-PGJ2 and 5-HETE) were observed. However TXB2 was decreased, and IL-2 and IL-10 levels were in-creased in survivors, if compared both to healthy subjects and deceased patients, who did not change their cytokine generation. Therefore, it seems that by triggering transcription factors granulocytes activate redox signaling, leading to the production of pro-inflammatory eicosanoids, while reducing cellular antioxidant capacity via SOD, they express altered response to COVID-19, which might result in the onset of the vicious cycle of systemic oxidative stress in deceased patients.

Oxidative stress driven by several environmental and local airway factors associated with chronic obstructive bronchiolitis, a hallmark feature of COPD, plays a crucial role in the disease pathomechanism. Unbalance between oxidants and antioxidant defense mechanisms not only amplifies the local inflammatory processes, but it also worsens cardiovascular health and contribute to the COPD related cardiovascular dysfunctions and mortality. The current review summarizes recent developments in our understanding of different mechanisms contributing to oxidative stress and its countermeasures with special attention to those that link local and systemic processes. Major regulatory mechanisms orchestrating these pathways are also introduced together with some suggestions for further research on the field.

Implantable drug-delivery systems provide new means for achieving therapeutic drug concentration over a prolonged time to achieve better tissue protection and enhanced recovery. The hypothesis of the current study was to test the antioxidant and anti-inflammatory effects of genistein and nanofibers on the spinal cord tissue following experimental spinal cord injury (SCI). Rats were treated post SCI with genistein loaded on chitosan/polyvinyl alcohol (CS/PVA) nanofibers as an implantable drug-delivery system. SCI caused marked oxidative damage and inflammation as evident by the reduction in the super oxide dismutase (SOD) activity and the level of interleukin-10 (IL-10) in injured spinal cord tissue, as well as, the significant increase in the levels of nitric oxide (NO), malondialdehyde (MDA) and tumor necrosis factor-alpha (TNF-α). Treatment of rats post SCI with genistein and CS/PVA nanofibers improved most of the above mentioned biochemical parameters and shifted them toward the control group values. Genistein induced an increase in the activity of SOD and the level of IL-10, while causing a decrease in the levels of NO, MDA and TNF-α in injured spinal cord tissue. Genistein and CS/PVA nanofibers provide a novel combination for treating inflammatory nervous tissue conditions, especially when combined as an implantable drug-delivery system.

Oxidative stress (OS) is reported in several chronic diseases. Extra-cellular superoxide dismutase (ec-SOD) catalyzes the dismutation of superoxide anion with a protective role on endothelial cells. In chronic kidney diseases (CKD), OS and thyroid dysfunction (low T3 syndrome) are fre-quently present, but their relationship has not been investigated. This cohort study evaluated ec-SOD activity in CKD patients during haemodialysis, divided into: “acute hemodialytic pa-tients” (AH, 1-3 months of treatment) and “chronic hemodialytic patients” (CH, treated for a longer period). We also evaluated plasmatic total antioxidant capacity (TAC) and the relation-ships with thyroid hormones. Two basal samples (“basal 1”, 3 days after the last dialysis and “basal 2”, 2 days after the last dialysis) were collected. On the same day of basal 2, a sample was collected 5 and 10 min after the standard heparin dose and at the end of the procedure. The ec-SOD values were significantly higher in CH vs AH in all determinations. Moreover, they pre-sented lower TAC values. Dividing CH patients into two subgroups according to fT3 levels (nor-mal or low) we found significantly lower ec-SOD values in the group with low fT3 at basal, 5 and 10 min samples. Finally, a significant correlation was observed between fT3 and ec-SOD in the basal 1 samples. These data, confirming OS and low T3 syndrome in CKD, suggest that low fT3 concentrations can influence ec-SOD activity and therefore contribute to possible endothelial oxi-dative damage in such a situation.

Superoxide, a form of reactive oxygen species (ROS), is catabolized by superoxide dismutase (SOD) and contributes to carcinogenesis via the oxidative damage it inflicts on cells. The aim of this research was to analyze the potential vitamin D-mediated regulation of the antioxidative “SOD1-to-SOD2 switch” within the human MG-63 osteosarcoma model. For this study; real-time PCR analysis was performed using MG-63 cells exposed to metabolically active 1,25(OH)₂D₃. Frist; a sustained statistically significant >2-fold suppression of proliferating cell nuclear antigen (PCNA) transcripts was observed after 10nM but not at 100nM of 1,25(OH)₂D₃ treatment; suggesting a cytostatic effect. In order to assess regulators of mitochondrial oxidative phosphorylation; gene expression of COX2 and COX4l1 of the mitochondrial complex IV and antioxidative enzymes (SOD1; SOD2 and Catalase (CAT)) were monitored. For COX2 and COX4l1; no changes in gene expression were observed. However; a concomitant decrease in CAT and SOD1 mRNA; and increase in SOD2 mRNA after 24 hours of 10nM 1,25(OH)₂D₃ treatment were observed. A ~8-fold increase in SOD2 mRNA was apparent after 48 hours. The significant increase in SOD2 activity in the presence of vitamin D indicates an antioxidant potential and sensitization of vitamin D during osteosarcoma transformation and mitochondrial detoxification over time.

A two-fold integrated research study was conducted; firstly, to understand effects of copper (Cu) and zinc (Zn) on the growth and oxidative stress in Nile tilapia, Oreochromis niloticus; secondly, to study the beneficial effects of the duckweed Lemna minor L. as a heavy metal remover from wastewater. Experiments were conducted in mesocosms with and without duckweed. Tilapia fingerlings were exposed to Cu (0.004 and 0.02 mg/L) and Zn (0.5 and 1.5 mg/L) and fish fed for four weeks. We evaluated the fish growth performance, the hepatic DNA structure using comet assay, the expression of antioxidative genes (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPx and glutathione-S-transferase, GST) and GPx and GST enzymatic activity. The results showed that Zn exhibited more pronounced toxic effects than Cu. Low dose of Cu did not influence the growth whereas higher doses of Cu and Zn significantly reduced the growth rate of tilapia compared to control, but addition of duckweed prevented weight loss. Further, in the presence of a high dose of Cu and Zn, DNA damage decreased, antioxidant gene expressions and enzymatic activities increased. In conclusion, results suggest that duckweed and Nile tilapia can be suitable candidates in metal remediation wastewater assessment programs.

To date, theoretical analyses have provided several useful methods/algorithms for studying transition states and non-covalent interactions. Potential Energy Scan (PES) is one such method that has found wide application in the physicochemical community. Analyzing the PES profiles of the catalytic system of FeBr3 in Electrophilic Aromatic Substitution (EAS) with molecular halogens, one can notice an obvious difference from the modern textbook mechanisms proposed in this area of study. Moreover, the newly presented Graphic Methodology (GM) allows a simple and reliable transition state determination even for very weakly bound charge transfer complexes using second-order derivatives as an efficient tool in the graphical analysis. Relative errors that can be reduced to a few parts per thousand in transition state estimation make this method a potentially very useful tool in further graphical studies of non-covalent interactions. Studies performed using high-precision semiempirical methods suggest that the process of halonium ion quenching proceeds along a completely different pathway, suggesting a possible novel transition metal-nonmetal catalytic system involved in the EAS electrophilic quenching step. The results presented here strongly suggest a future GM application that is widely used and the introduction of pseudo and pre-transition states as new terms in the description of non-covalent interactions.