Evaluating Biofilm Inhibitory Potential in Fish Pathogen, Aeromonas hydrophila by Agricultural Waste Extracts and Assessment of Aerolysin Inhibitors Using In Silico Approach.

Aeromonas hydrophila, an opportunistic bacteria, causes several devastating diseases in humans and animals, particularly aquatic species. Antibiotics have been constrained by the rise of antibiotic resistance caused by drug overuse. Therefore, new strategies are required to prevent appropriate antibiotic inability from antibiotic-resistant strains. Aerolysin is essential for A. hydrophila pathogenesis and has been proposed as a potential target for inventing drugs with anti-virulence properties. It is a unique method of disease prevention in fish to block the quorum-sensing mechanism of A. hydrophila. In SEM analysis, the crude solvent extracts of both groundnut shells and black gram pods exhibited a reduction of aerolysin formation and biofilm matrix formation by blocking the QS in A. hydrophila. Morphological changes were identified in the extracts treated bacterial cells. Furthermore, in previous studies, 34 ligands were identified with potential antibacterial metabolites from agricultural wastes, groundnut shells, and black gram pods using a literature survey. Twelve potent metabolites showed interactions between aerolysin and metabolites during molecular docking analysis, in that H-Pyran-4-one-2,3 dihydro-3,5 dihydroxy-6-methyl (-5.3 kcal/mol) and 2-Hexyldecanoic acid (-5.2 kcal/mol) showed promising results with potential hydrogen bond interactions with aerolysin. These metabolites showed a better binding affinity with aerolysin for 100 ns in molecular simulation dynamics. These findings point to a novel strategy for developing drugs using metabolites from agricultural wastes that may be feasible pharmacological solutions for treating A. hydrophila infections for the betterment of aquaculture.

Sustainable fabrication of hybrid silver-copper nanocomposites (Ag-CuO NCs) using Ocimum americanum L. as an effective regime against antibacterial, anticancer, photocatalytic dye degradation and microalgae toxicity.

In this study, a sustainable fabrication of hybrid silver-copper oxide nanocomposites (Ag-CuO NCs) was accomplished utilizing Ocimum americanum L. by one pot green chemistry method. The multifarious biological and environmental applications of the green fabricated Ag-CuO NCs were evaluated through their antibacterial, anticancer, dye degradation, and microalgae growth inhibition activities. The morphological features of the surface functionalized hybrid Ag-CuO NCs were confirmed by FE-SEM and HR-TEM techniques. The surface plasmon resonance λmax peak appeared at 441.56 nm. The average hydrodynamic size distribution of synthesized nanocomposite was 69.80 nm. Zeta potential analysis of Ag-CuO NCs confirmed its remarkable stability at -21.5 mV. XRD and XPS techniques validated the crystalline structure and electron binding affinity of NCs, respectively. The Ag-CuO NCs demonstrated excellent inhibitory activity against Vibrio cholerae (19.93 ± 0.29 mm) at 100 µg/mL. Anticancer efficacy of Ag-CuO NCs was investigated against the A549 lung cancer cell line, and Ag-CuO NCs exhibited outstanding antiproliferative activity with a low IC50 of 2.8 ± 0.05 µg/mL. Furthermore, staining and comet assays substantiated that the Ag-CuO NCs hindered the progression of the A549 cells and induced apoptosis as a result of cell cycle arrest at the G0/G1 phase. Concerning the environmental applications, the Ag-CuO NCs displayed efficient photocatalytic activity against eosin yellow degradation up to 80.94% under sunlight irradiation. Microalgae can be used as an early bio-indicator/prediction of environmental contaminants and toxic substances. The treatment of the Ag-CuO NCs on the growth of marine microalgae Tetraselmis suecica demonstrated the dose and time-dependent growth reduction and variations in the chlorophyll content. Therefore, the efficient multifunctional properties of hybrid Ag-CuO NCs could be exploited as a regime against infective diseases and cancer. Further, the findings of our investigation witness the remarkable scope and potency of Ag-CuO NCs for environmental applications.

Exploration of marine red seaweed as a dietary fish meal replacement and its potentiality on growth, hematological, biochemical, and enzyme activity in freshwater fish Labeo rohita.

The present study investigated the dietary fishmeal replacement by marine red seaweed (Halymenia dilatata) meal (RSM) on growth performance, feed utilization, chemical body composition, hematological constituents, digestive, antioxidant, and metabolic enzymes in freshwater fish Labeo rohita (Rohu) fingerlings. The fish were fed with RSM-free control diet (RSM0) and four experimental diets, which replaced fish meal (FM) with varying levels of RSM (25%, 50%, 75%, and 100%, represented as RSM25, RSM50, RSM75, and RSM100 respectively). After a 60-day feeding trial, the survival rate (SR), growth performance (length gain, weight gain, and specific growth rate), protein efficiency ratio, chemical body composition (protein, lipid, and ash), and digestive enzymes (amylase and protease) were significantly increased (P < 0.05) in the fish fed with RSM50 diet containing 39% protein level. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed a higher staining intensity of muscle proteins in fish fed with the RSM50 diet. However, the hematological constituents (hemoglobin, hematocrit, red blood cell, white blood cell, mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration), antioxidant enzyme - superoxide dismutase, and metabolic enzymes (glutamic oxaloacetic transaminase and glutamic pyruvic transaminase) were not significantly altered in RSM50 diet when compared to control. In contrast, hematological constituents were decreased (P < 0.05), and antioxidant and metabolic enzymes were increased in rohu fed with RSM75 and RSM100 (P < 0.05). Furthermore, these findings suggest that RSM might be adopted at a pace of 37% (estimated polynomial second-order regression) and is found to be beneficial for freshwater fish L. rohita diets that enhance growth and immune responses. The current study recommended substituting (50%) of marine red seaweed (Halymenia dilatata) for fish meal significantly improves the growth performance, chemical body composition, and digestive enzymes of L. rohita and this could be a valuable natural replacement for fishmeal to reduce the production cost of aquatic feed.

Biofabrication of ecofriendly copper oxide nanoparticles using Ocimum americanum aqueous leaf extract: analysis of in vitro antibacterial, anticancer, and photocatalytic activities.

Nanotechnology tends to be a swiftly growing field of research that actively influences and inhibits the growth of bacteria/cancer. Noble metal nanoparticles (NPs) such as silver, copper, and gold have been used to damage bacterial and cancer growth over recent years; however, the toxicity of higher NPs concentrations remains a major issue. The copper oxide nanoparticles (CuONPs) were therefore fabricated using a simple green chemistry approach. Biofabricated CuONPs were characterized using UV-visible, FE-SEM with EDS, HR-TEM, FT-IR, XRD, Raman spectroscopy, and XPS analysis. Formations of CuONPs have been observed by UV-visible absorbance peak at 360.74 nm. The surface morphology of the CuONPs showed the spherical structure and size (~ 68 nm). The EDS spectrum of CuONPs has proved to be the key signals of copper (Cu) and oxygen (O) components. FT-IR analysis, to validate the important functional biomolecules (O-H, C=C, C-H, C-O) are responsible for reduction and stabilization of CuONPs. The monoclinic end-centered crystalline structures of CuONPs were confirmed with XRD planes. The electrochemical oxygen states of the CuONPs have been studied using spectroscopy of the Raman and X-ray photoelectron. After successful preparation, CuONPs examined their antibacterial, anticancer, and photocatalytic activities. Green-fabricated CuONPs were promising antibacterial candidate against human pathogenic gram-negative bacteria Escherichia coli, Vibrio cholerae, Salmonella typhimurium, Klebsiella pneumoniae, Aeromonas hydrophila, and Pseudomonas aeruginosa. CuONPs were demonstrated the excellent anticancer activity against A549 human lung adenocarcinoma cell line. Furthermore, CuONPs exhibited photocatalytic degradation of azo dyes such as eosin yellow (EY), rhodamine 123 (Rh 123), and methylene blue (MB). Biofabricated CuONPs may therefore be an important biomedical research for the aid of bacterial/cancer diseases and photocatalytic degradation of azo dyes.

Effects of graded levels of mineral mixtures (Aquamin® and Agrimin®) supplemented diets on growth, survival, proximate composition, and carcass mineralization of juvenile freshwater prawn, Macrobrachium malcolmsonii (H Milne-Edwards 1844).

The present study investigated the effects of Aquamin® mineral mixture (AQMM) and Agrimin® mineral mixture (AGMM) supplemented diets on growth and chemical composition of juvenile freshwater prawn Macrobrachium malcolmsonii (H. Milne-Edwards, 1844). Experimental diets containing 6 different AQMM levels (Trial 1: 0, 0.5, 1.0, 1.5, 2.0, and 2.5%) and 6 different AGMM levels (Trial 2: 0, 0.5, 1.0, 1.5, 2.0, and 2.5%) were formulated to feed juvenile prawn [initial body weight of 0.82 ± 0.05 g (Trial 1) and 1.24 ± 0.03 g (Trial 2)] for 60 days. Prawn fed diets containing 1.0% of AQMM and AGMM showed significantly increased (P < 0.05) survival rate, weight gain, specific growth rate, protein efficiency ratio, edible flesh weight, and proximate composition (moisture, crude protein, crude fat, and ash), while feed intake and feed conversion ratio were significantly decreased (P < 0.05). Whereas, 1.5-2.5% of AQMM- and AGMM-supplemented diets fed prawn showed a reverse trend when comparing other groups. Moreover, the minerals (macro elements: Ca, P, Mg, Na, and K; trace elements: Cu, Zn, and Fe) were significantly increased (P < 0.05) in the carcass of prawn when fed with 2.5% AQMM- and AGMM-supplemented diets. The present results suggest that the optimal dietary supplementation of AQMM and AGMM at a concentration of up to 1.06 and 1.02%, respectively (based on polynomial regression analysis), improved growth and enhanced the crude protein level of juvenile prawn.

Activity profile of innate immune-related enzymes and bactericidal of freshwater fish epidermal mucus extract at different pH.

The epidermal mucus of fish performs diverse functions from prevention of mechanical abrasion to limit pathogen invasions. The current experiment was designed to extract skin mucus proteins of three freshwater fish, i.e. common carp (Cyprinus carpio), mrigal (Cirrhinus mrigala) and rohu (Labeo rohita) with organic solvent (methanol) and dissolve in different pH of Tris-HCl buffers to examine the significance of pH in the solubilisation of skin mucus proteins. The protein profiles of different pH solubilised methanol fish skin mucus extracts were determined by SDS-PAGE. The non-specific immune enzymes, alkaline phosphatase, lysozyme and protease of fish skin mucus were compared and this present study demonstrated that these enzymes differed in their activity depending on pH buffers. The higher lysozyme and protease activity were observed at the pH of 8.0 and higher alkaline phosphatase activity in the pH 9.0 of C. mrigala fish skin mucus methanol extract. In addition, the bactericidal activity was evaluated against the pathogens Proteus vulgaris and Pseudomonas aeruginosa. The pH 8.0 of C. mrigala skin mucus extract revealed better bactericidal activity than other fish species mucus pH buffers against both P. vulgaris and P. aeruginosa. In the case of protein profile from SDS-PAGE, based on pH buffers and the solubilisation of proteins, differences in the resolution of bands were observed. The higher alkaline pH of 9.0 showed smeared gel bands in all the three fish skin mucus methanol extract. The present study suggests that methanol extracted C. mrigala fish skin mucus at pH 8.0 showed better innate immune enzymes and bactericidal activity. The additional examinations of C. mrigala skin mucus methanol extract in this pH aids in identifying novel bioactive molecules. This is the study of proteome of three fish species skin mucus in the effect of pH. Further analyses are required to evaluate proteins present in fish skin mucus extracted with methanol and the influence of pH on protein solubility. These findings could be helpful in exploring natural alternatives to antibiotics in aquaculture industry against infectious pathogens.