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Metallic nanoparticles are widely used in cosmetics, food products and textile industry. These particles are known to cause respiratory toxicity and epithelial inflammation. They are eventually released to aquatic environment necessitating toxicity studies in cells from respiratory organs of aquatic organisms. Hence, we have developed and characterized a new cell line, WAG, from gill tissue of Wallago attu for toxicity assessment of TiO2 and ZnO nanoparticles. The efficacy of the cell line as an in vitro system for nanoparticles toxicity studies was established using electron microscopy, cytotoxicity assays, genotoxicity assays and oxidative stress biomarkers. Results obtained with MTT assay, neutral red uptake assay and lactate dehydrogenase assay showed acute toxicity to WAG cells with IC50 values of 25.29±0.12, 34.99±0.09 and 35.06±0.09 mg/l for TiO2 and 5.716±0.1, 3.160±0.1 and 5.57±0.12 mg/l for ZnO treatment respectively. The physicochemical properties and size distribution of nanoparticles were characterized using electron microscopy with integrated energy dispersive X-ray spectroscopy and Zetasizer. Dose dependent increase in DNA damage, lipid peroxidation and protein carbonylation along with a significant decrease in activity of Superoxide Dismutase, Catalase, total Glutathione levels and total antioxidant capacity with increasing concentration of exposed nanoparticles indicated that the cells were under oxidative stress. The study established WAG cell line as an in vitro system to study toxicity mechanisms of nanoparticles on aquatic organisms.

Evidence from animal studies categorizes sporadic Alzheimer's disease (sAD) as a metabolic syndrome with accompanying cognitive deficits. Given that glial cells act as "silent partners" to neurons by providing trophic support and defense, the present study investigated the role of glia in sAD pathology. A streptozotocin (STZ)-induced glial-neuronal co-culture model of sAD was used to study the metabolic status of the two cell types. Real time RT-PCR and Western blotting results indicated that amyloid precursor protein (APP) and β-secretase (BACE1) were highly expressed in co-cultured neurons than in monocultures. Increased amyloidogenesis was accompanied by decreased expression of mediators in insulin signaling pathway that included insulin receptor (IR), insulin receptor substrate 2 (IRS2), insulin-like growth factor 2 (IGF2), insulin-like growth factor 1 receptor (IGF1R), total-glycogen synthase kinase 3β (t-GSK3β), and phosphorylated-GSK3β (p-GSK3β), suggesting that neuronal cells are more prone to metabolic variability when cultured in the presence of glial cells. Findings from the sAD model induced by intracerebroventricular (ICV) injection of STZ revealed that increased amyloid beta (Aβ) load in the hippocampus was potentially responsible for the hyperphosphorylation of tau at ser. Furthermore, impaired cognitive functions and decreased dendritic spine density and axonal thinning in CA1 region of hippocampus were associated with decreased IR and p-GSK3β/t-GSK3β expression. Taken together, the present study provides evidence that glia mediated response and insulin signaling defects drive pathological changes in sAD and represent potential targets for delaying sAD progression.

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Ten successful trials on induced breeding of the striped murrel Channa striata (Bloch, 1793) under indoor conditions were carried out during July-August 2019. Brooders reared in cement tanks,(males weighing in the range of 290-700 g and females 220-600 g), were used in a set of 2:2 male to female ratio for induced breeding with salmon gonadotropin releasing hormone anologue (sGnRHa) and dopamine antagonist commercial formulation. Each brooder set was kept in an FRP tank (13’x3’x14’’) along with submerged macrophyte Hydrilla verticillata, which was sparsely spread all around the tank. Maturity of brooders was screened on the basis of secondary sexual traits. The brooders were given hormonal injection after 6 h of acclimatisation under indoor conditions @ 1 ml kg-1 body weight (containing sGnRHa 20 µg ml-1 and domperidone 10 µg ml-1) to both the sexes. Natural spawning occurred in all ten sets within 21.5+3.2 h (17-26 h) of injection. In all the tanks, two separate egg masses were observed with 30-95% fertilisation. Approximately 0.14 million eggs were scooped out from the tanks and reared in round plastic tanks (70 l) for hatching, where hatching occurred within 17-26 h post-fertilisation (hpf) with hatching rates of 50.76 to 93.18% at 28+2oC. The embryonic development was recorded under a stereo-zoom microscope in live condition under controlled temperature conditions and described with digital images. The study revealed that induced breeding of C. striata can be undertaken in FRP tanks under indoor conditions for mass-scale seed production, which will provide a platform for diversification of this high valued fish species for large scale farming practices in ponds as well a new species for culture in recirculatory aquaculture system (RAS) and biofloc technology (BFT).