Although, the 4-NP effects on fish’s reproductive hormones was assessed in several studies using adults’ models; however, the effect of this endocrine disruptor on immature fish’s reproductive hormones was not addressed commonly. This study aimed to study the reproductive toxicity and recovery associated with 4-nonylphenol exposure in juvenile African catfish (Clarias garepinus) using some hormones (17β‐estradiol (E2), Testosterone (T), follicle stimulating hormone (FSH) and luteinizing hormone (LH)) and gonads histology as biomarkers. Toxic effects of 4-nonylphenol (4-NP) has been studied in many anmails models but still there is limited knowledge about the dose-dependent damage caused by 4-NP exposure in juvenile Clarias gariepinus. Healthy juvenile C. gariepinus categorized into four groups (n=3/ group; three replicates in each group). The first group was the control, and the other three groups were subjected to 4-NP concentrations as 0.1 mg/L, 0.2 mg/L, and 0.3 mg/L, respectively for 15 days, then were left for a recovery period of another 15 days. The reproductive hormones of C. gariepinus exposed to 4-NP for 15 days exhibited significant variations between treatments and the control (P < 0.05) were evident in E2 and T values, whereas FSH, LH, total protein and lipid peroxidation values showed non-significant difference among all groups. Such situation referred to the fact that the 15-day recovery period was insufficient to remove the impacts of 4-NP doses in concern. The trend of dose-dependent increase/decrease was recorded for T, E2, FSH, and LH. The histopathological alterations of 4-NP-treated in gonads tissues were recorded in juvenile of C. gariepinus reflecting their sensitivity to 4-NP-estrogenic like effects. Overall, our results investigate that recovery has improved the reproductive toxicity caused by 4-nonylphenol in juvenile of C. garepinus. Significant variations between the treated groups and the control group (P < 0.05) were evident in all parameters except for the Hb, MCV, MCH and MCHC. The parameters exhibiting significance decreased with such increased doses. Apoptotic frequency in erythrocytes and brain cells increased significantly with increased 4-NP exposure, indicating that 4-NP caused cytotoxic effects, such as apoptosis in a dose-dependent manner. However, these cellular alterations greatly decreased after the 15-day recovery period.

This study was conducted to explore the protective potential of three different antioxidant supplements, lycopene, citric acid, and Chlorella , against reproductive injuries induced by microplastics (MPs) in freshwater mature male catfish. A total of 150 mature male African catfish ( Clarias gariepinus ) were assigned to five treatment groups as follows: control group fish were fed with control diet, the second group fish were fed with 500 mg/kg MP diet, and the remaining three groups of fish were fed with 500 mg/kg MP diet plus lycopene (500 mg/kg diet), citric acid (30 g/kg diet), and Chlorella (50 g/kg diet), respectively, for 15 days. Ingestion of MPs significantly decreased serum luteinizing hormone, follicle-stimulating hormone, sex steroid (testosterone and estradiol) levels and sperm count, spermatocrit, motility, and viability. It also induced histological alterations and degenerative changes in testicular tissues. Administration of lycopene and Chlorella with MP diets maintained hormone levels comparable to those in the control group, enhanced sperm quality, and decreased testicular histological damage. Chlorella was more effective in enhancing sperm quality, and lycopene was more efficient in alleviating testicular tissue damage. Citric acid supplementation was irrelevant in mitigating MP-induced injury. This study indicated that both lycopene and Chlorella ameliorated the MP-induced reproductive dysfunction by improving reproductive hormonal levels, sperm parameters, and histological configuration, whereas the citric acid dose used in this study was not effective in ameliorating the MP-induced reproductive stress. Additional research and monitoring of MP-induced pollution in freshwater ecosystems are required to avoid the severity of reproductive toxicity in freshwater fish.

Ethidium bromide (EtBr) is one of the contaminants recorded in aquatic environments whose effects have been investigated; however, there is still limited knowledge about its remediation. This study examined the potential protective effects of Spirulina platensis (SP) against the effects of EtBr toxicity in the Nile tilapia (Oreochromis niloticus) fry. Fry were divided to five groups, viz., a control and four treatment groups of low-dose EtBr (10 μg/ L), low-dose EtBr with SP (10 μg/L EtBr + 200 mg/L SP), high-dose EtBr (100 μg/L), and high-dose EtBr with SP (100 μg/L EtBr + 200 mg/L SP); the exposure period was 2 weeks. Low and high doses of EtBr induced alterations in some hematological, biochemical, and histopathological parameters. Necrotic hepatocytes, degenerated area, vacuolated hepatocytes, pyknotic nuclei, constricted and dilated blood sinusoids, and infiltration of in-flammatory cells were observed. Lipid peroxidation concentration was not significantly different in groups exposed to low doses of EtBr and EtBr with SP, but it was increased in groups exposed to high doses of EtBr and EtBr with SP, compared with the control group. After feeding with SP, most histological and histochemical parameters restored to normal values. Therefore, SP may possess the ability to preserve the structural integrity of the he-patic and renal membranes.

Ternary Co₃O₄-Ni(OH)₂-graphene hybrid nanocomposites (NCs) can be fabricated using a facile, room-temperature kinetic spray process in a single step. The fabricated heterostructure electrodes are optimized to enhance the oxygen evolution reaction (OER) in 1.0 M KOH. The deposited films exhibit a mixture of nanosheet and nanoflake morphologies. Raman spectra reveal improvements in various disorder-related modes in the hybrid NCs due to the nanometer scale and the transformation of graphite-stacked layers into thin graphene nanosheets. X-ray photoelectron spectra indicate that strong synergy improvements in the heterostructure NCs are associated with a downshift of the active state’s binding energies. Optimal Co₃O₄-Ni(OH)₂-graphene hybrid ternary NCs exhibit the smallest OER overpotential of 262 mV @10 mA·cm⁻², the lowest Tafel slope of 32 mV·dec⁻¹, and long-term stability of 25 h at a polarization current of 50 mA·cm⁻².

A gold nanoparticle decorated functionalized nanocarbon black (Au@f-NCB) hybrid nanocomposite–modified molecular wire glassy carbon paste electrode (MW-GCPE) was constructed for sensitive determination of anticancer drug formestane (FMST) by square-wave adsorptive anodic stripping voltammetry (SW-AASV). The synthesized Au@f-NCB hybrid nanocomposite was characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and dispersive X-ray spectroscopy (EDX). The fabricated Au@f-NCB/MW-GCPE was found to have higher electrocatalytic activity towards the oxidation of FMST than bare GCPE. The developed electrochemical sensor allowed the ultrasensitive and selective detection of FMST with a linear range (0.02–5.2 µM), low limit of detection (7.14 nM), and high sensitivity (90.0 μAμM⁻¹ cm⁻²). The constructed Au@f-NCB nanocomposite modified MW-GCPE revealed good repeatability, reproducibility, and higher stability. Furthermore, the developed sensor has been shown to be highly sensitive for detecting FMST in human fluids, Lentaron depot ampoules, and patient plasma. In addition, electrosensing of FMST in the presence of the anti-cancer chemotherapy drug doxorubicin (DOX) was explored, and simultaneous detection of the two drugs was achieved.