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Haloarchaea from high saline habitats are known to contain industrially important value-added bioactive compounds such as bacteriorhodopsin, carotenoids, lipids, and proteins. The diversity of Haloarchaea from geographically less explored saline habitats has received less attention. In this study isolation and characterization of the biotechnological potential of novel haloarchaea strains from solar saltern, a hypersaline environment in Marakanam, Tamilnadu was carried out. The samples were collected during the pre-monsoon (July) and post-monsoon (January) season and ten different haloarchaea strains were isolated. UV-Vis spectroscopy analysis revealed the bacteriorhodopsin production by all the isolated strains. Further experiments were carried out to estimate the yield of bacteriorhodopsin and to assess their photocurrent activity and biosensor applications. The maximum yield of bacteriorhodopsin was 5.6 mg/L of cultured lysate. This study will contribute to a better understanding on effect of elicitors on bacteriorhodopsin producing different haloarchaea strains and growing knowledge on their biotechnological applications. [ABSTRACT FROM AUTHOR]

Ice-ice disease occurs in cultivated algal seaweed Kappaphycus alvarezii due to pathogenic bacterial infections. This seaweed has rich source of carrageenan widely known as the kappa carrageenan. Generally, ice-ice disease leads to whitening of the branches initiated with colour changes of the thalli, which become transparent in the end. This study was aimed to isolate and identify the bacteria based on morphology and biochemical characterization on ice-ice diseased K. alvarezii from three different places, namely, Kottapatinam, Thondi and Rameswaram. The bacterium was isolated in Zobell Marine Agar (ZMA) and thiosulfate-citrate-bile saltsucrose (TCBS) agar. Morphological and biochemical characterizations revealed that the isolated bacteria causing ice-ice disease were closely related to the genera Bacillus in ZMA and Vibrio species in TCBS. Total viability count, physical and chemical properties of the bacteria by gram staining and morphological analysis were done for all species isolated from three places. [ABSTRACT FROM AUTHOR]

In this study, an attempt has been made to explore the antifouling activity of the marine halotolerant bacterium, namely, Bacillus sp. About 10 different bacteria were isolated using the Zobell marine agar medium from the marine sediment samples that were collected from the Marina beach, Bay of Bengal, India. The growth pattern tests of the 10 bacteria were documented. Among the 10 different isolates, two exhibited the protease activity in skim milk agar. The antifouling activity was further tested against five different fouling bacteria. The antifouling activity of alkaline protease isolated from Bacillus sp. inferred that it exhibited pronounced inhibitory zones against fouling bacterial strains with least minimal inhibitory concentration range between 25 and 100 units/mg protein. Anticrustacean assay was performed using Artemia salina of alkaline protease, which showed good activity. The results suggest that Bacillus sp. produced an extracellular alkaline protease, which was responsible for the antifouling and algicidal activity of marine fouling organisms. This study tends to indicate that Bacillus sp. could be further explored for the development of new antifouling agents. [ABSTRACT FROM AUTHOR]

Liposomes were prepared in the laboratory with lipids obtained from chicken egg yolk to encapsulateSpirulinapowder.Artemianapulii were hatched and fed with lipid-encapsulatedSpirulinaorSpirulinapowder. After 20 days of rearing, the experimentalA. salinawere harvested and measured for total body length and total content of protein and carbohydrates. Total body length was 45% higher, protein content was 49% higher, and carbohydrate was 35% higher inArtemiafed with liposomes as compared with those fed onlySpirulinapowder. [ABSTRACT FROM AUTHOR]

Pathogen infections in shrimps trigger the release of reactive oxygen species (ROS) as a part of immune response. The excessive accumulation of ROS causes the production of oxidative stress, which leads to oxidative damage of the biomolecules in the host cells. The inclusion of dietary antioxidants is known to mitigate oxidative stress and stimulate immunity. Curcumin, a potential antioxidant was encapsulated in chitosan nanoparticles to surge its bioavailability and was administered orally to Vibrio harveyi challenged and non-challenged Litopenaeus vannamei. The non-challenged shrimps fed with curcumin-loaded chitosan nanoparticles (Cur-CSNPs) showed a significant increase (p ≤ 0.05) in the specific growth rate, daily growth coefficient and survival rate. A significant increase (p ≤ 0.05) in the phenoloxidase activity, total hemocyte count and superoxide dismutase activity was observed in both the challenged and non-challenged shrimps fed with Cur-CSNPs. Additionally, a significant increase (p ≤ 0.05) in the relative mRNA expression of lysozyme, cMnSOD and lectin was observed in the Cur-CSNPs fed shrimps. The findings of this research suggest that Cur-CSNPs reinforce the immune system of L. vannamei against V. harveyi infection. Moreover, the non-challenged shrimps showed improvement in the growth parameters in addition to immunostimulation. Thereby a routine inclusion of dietary Cur-CSNPs could mitigate the oxidative damage caused by the incidence of environmental or pathogen-mediated oxidative stress., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Chitosan nanoparticles (CSNPs) have been recently used for various applications in aquaculture, especially as drug carriers. The aim of this study was to synthesise and investigate a superlative method of CSNP synthesis for application in aquaculture through aquaculture-based toxicology screening methods. Two different methods were analysed: the first a direct ionic gelation method (A) and the other involving a low-molecular-weight chitosan microparticle intermediate method (B). Dynamic light scattering characterisation revealed that the CSNP particle sizes were 192.7 ± 11.8 and 22.9 nm from methods A and B, respectively. The LC 50 values for brine shrimp toxicity were found to be 1.51 and 0.02 ppt in 24 h for methods A and B, respectively. Acute toxicity studies in Litopenaeus vannamei rendered LC 50 values of 3235.94 and 2884.03 ppt in 24 h for methods A and B, respectively. Zebrafish toxicity studies revealed mortality rates of 21.67% and 55% at 20 mg/L concentration for methods A and B, respectively, with an increased expression of intracellular reactive oxygen species in method B. From these findings, it can be concluded that a comparatively reduced toxicity of CSNPs derived from ionic gelation method makes it more appropriate for application in aquaculture., (© 2021 The Authors. IET Nanobiotechnology published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.)

Chitosan nanoparticles (CSNPs) have been recently explored as a potential drug carrier to enhance the bioavailability and aqueous solubility of drugs. Curcumin, an antioxidant with a remarkable antiradical scavenging activity was encapsulated in CSNPs to revamp its bioavailability. While changes in the optimal farming condition can induce oxidative stress in the animals, curcumin loaded chitosan nanoparticles (Cur-CSNPs) were amalgamated into shrimp feed pellets to ameliorate its antioxidant content in an attempt to bolster the organisms against oxidative stress. Cur-CSNPs were synthesized in two different concentrations of curcumin as Cur-CSNPs A and B. Characterization of the synthesized Cur-CSNPs revealed asymmetrical nanoparticles with semispherical geometry and a zeta potential ˃50 mV. HPLC studies substantiated encapsulation efficiencies of 77.53% and 80.35% for Cur-CSNPs A and B respectively. DPPH, ABTS and FRAP assays manifested a significant enhancement in the antioxidant property of the Cur-CSNPs fortified feed pellets. This is the first study to investigate and demonstrate the ability of Cur-CSNPs to enhance the antioxidant property of aquaculture feed pellets. These findings substantiate that Cur-CSNPs fortified feed may be applied to reinforce aquaculture animals against oxidative stress., (Copyright © 2020 Elsevier B.V. All rights reserved.)