Composition of heavy metals in sediment, water, and fish of the Ganga and Yamuna Rivers in two major cities of India.

The rapid industrial development in the Indian capital region has led to significant waste generation, which, despite undergoing treatment prior to disposal, contributes substantially to water body contamination. Given the diverse nature of these wastes and their potential repercussions across the food chain, a study was conducted to evaluate heavy metal contamination levels in the Ganga and Yamuna Rivers of two major cities. Six heavy metals (Pb, Cd, Hg, Cu, Cr, and Zn) were analyzed in fish, water, and sediment samples by utilizing flame atomic absorption spectrophotometry (Avanta Σ) from March 2019 to February 2020. Results revealed distinct heavy metal distribution patterns, with Cr > Zn > Pb > Cu > Cd > Hg in the Ganga River and Zn > Cr > Pb > Cu > Cd > Hg in the Yamuna River for fish samples. Additionally, levels of Hg in Cyprinus carpio and Sperata oar from the Ganga River, and Pb, Cd, Hg, and Cr in Salmophasia bacaila and Mystus cavasius from the Yamuna River exceeded WHO/FAO permissible limits. In water samples, the predominant heavy metal sequences were Pb > Cu > Zn > Cr > Cd > Hg for the Ganga River and Cr > Zn > Pb > Cu > Cd > Hg for the Yamuna River, with Pb, Cr, Zn, and Cd surpassing WHO standards. Sediment analysis revealed varying heavy metal compositions, with Zn > Cr > Pb > Cu > Cd > Hg in the Ganga River and Cr > Zn > Pb > Cu > Cd > Hg in the Yamuna River. While drinking water and fish from the Ganga River were deemed safe for consumption, those from the Yamuna River were not. Given the toxic nature of heavy metals and their detrimental health impacts, regular monitoring and effective management strategies are imperative.

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.