Synthesis of Iron Nanoparticles Using Sargassum wightii Extract and Its Impact on Serum Biochemical Profile and Growth Response of Etroplus suratensis Juveniles.

The present study focuses on the green synthesis of iron nanoparticles using plant extracts as reducing, capping, and stabilizing agents. Aqueous seaweed extracts with the addition of iron solution were mixed using a magnetic stirrer which resulted in a color change indicating the formation of iron nanoparticles. The iron nanoparticles were successfully synthesized using Sargassum wightii extract. The synthesized iron nanoparticles were characterized by UV-Vis spectrophotometer, Fourier transform infrared spectroscopy (FTIR), and zeta potential techniques. The UV-Vis spectra showed a peak at 412 to 415 nm. Zeta potential revealed that the synthesized iron nanoparticles were negative and positive charges. FTIR spectroscopy analysis showed the presence of chemical bond and amide group likely to be responsible for the green synthesis of iron nanoparticles. The effect of nano-iron as a dietary iron source on the growth and serum biochemical profile of Etroplus suratensis fingerlings was evaluated. Iron nanoparticles were fed to E. suratensis fingerlings for 60 days with two levels 10 mg (T1) and 20 mg (T2) and a control group without iron nanoparticles. The highest WG% and SGR and lowest FCR were observed in the T2 group which is significantly different (p < 0.05) from other groups. The serum biochemical profile showed significantly increased activity on 20 mg/kg of nano-iron-supplemented diet. The findings of the present study concluded that supplementation of nano-iron at the 20 mg/kg level to the regular fish diet has a better impact not only on growth but also on the overall health of the fish.

Computational analysis and functional characterisation of Tor putitora toll-like receptor 4 with the elucidation of its binding sites for microbial mimicking ligands.

In the current study, full-length Toll-like receptor 4 (TLR4) cDNA was cloned and characterised in Tor putitora, an important fish inhibiting Himalayan rivers. The complete coding sequence of TpTLR4 is 2457 bp with nine key structural domains, including six leucine-rich repeats (LRRs). The phylogenetic tree revealed that TpTLR4 showed the closest relationship with TLR4 of Cyprinus carpio (96%), Labeo rohita (91%) and Megalobrama amblycephala (88%), all belonging to the Cyprinidae family. CELLO2GO tool revealed that TpTLR4 protein is highly localised in the plasma (67.7%), and the protein has a strong association with myeloid differentiation primary response 88 (MYD88) followed by Tumor necrosis factor receptor-associated factor (TRAF) family. In the toll-interleukin-1 receptor (TIR) domain of TpTLR4, the proline is replaced by the alanine amino acid, thus may give plasticity to the receptor to recognise both bacterial and viral ligands. Molecular docking has revealed that TpTLR4 showed the strongest affinity towards poly (I:C) with the binding energy of -6.1 kcal/mol and five hydrogen bonds among all ligands. Based on our molecular docking results, it can be presumed that TpTLR4 can sense bacterial, fungal and viral molecular patterns with binding sites mainly present in the TpTLR4 LRR9 motif, which spans between 515 and 602 amino acids. Tor putiora TLR4 transcript was ubiquitously expressed in all the tested fish tissues. Although, transcript level was found to be highest in blood and spleen followed by the kidney. The TpTLR4 transcripts showed peak expression in spleen and kidney at 12 h post-injection (hpi) (p < 0.05) of poly (I:C). The constitutive expression of TpTLR4 in various tissues, up-regulation in different tissues and strong binding affinities with poly (I:C) indicate that TpTLR4 may play an essential role in sensing pathogen-associated molecular patterns (PAMPs), particularly of viral origin.