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The impact of contaminants on Copepod sp. and its molecular response is least explored, despite their abundance and dominance among invertebrates in aquatic environments. In the present investigation, Dioithona rigida, a cyclopoid zooplankton, was treated with selenium nanoparticles (SeNPs) to determine the associated biochemical changes, and the chronic exposure effects were recorded using transcriptomic analysis. It was found that, SeNPs were acutely toxic with a lethal dose 50% of 140.9 mg/L. The de novo assembled transcriptome of the copepod comprised 81,814 transcripts, which underwent subsequent annotations to biological processes (23,378), cellular components (21,414), and molecular functions (31,015). Comparison of the expressed transcripts against the treated sample showed that a total of 186 transcript genes were differentially expressed among the D. rigida treatments (control and SeNPs). The significant downregulated genes are coding for DNA repair, DNA-templated DNA replication, DNA integration, oxidoreductase activity and transmembrane transport. Similarly, significant upregulations were observed in protein phosphatase binding and regulation of membrane repolarization. Understanding the impact of SeNPs on copepods is crucial not only for aquatic ecosystem health but also for human health, as these organisms play a key role in marine food webs, ultimately affecting the fish consumed by humans. By elucidating the molecular responses and potential toxicological effects of SeNPs, this study provides key insights for risk assessments and regulatory policies, ensuring the safety of seafood and protecting human health from the unintended consequences of nanoparticle pollution.

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]

Mitochondrial genome sequences provide excellent insight into the study of molecular phylogeny and evolution. Mobula tarapacana (Sicklefin devil ray) has an olive-green to brown colored dorsal surface and darkly colored ventral markings. Due to their grey ventral stripes, fisherman and divers sometimes mistake these species for manta rays. To avoid the misidentification during bycatch and to increase the scientific knowledge of this resource as per the SDG Target 14.A, the complete mitogenome sequence of Sicklefin devil ray was sequenced, annotated, and submitted to the GenBank (Accession: MH669414.1). The mitogenome of M. tarapacana is a closed circular dsDNA of 5, 686 bp in size, which transcribes into 13 protein-coding genes (PCGs), 22 tRNAs, and 2 rRNAs. The percentage of protein-coding genes in the genome was 60.30%. Each protein-coding gene is initiated with an ATG codon excluding COX1 and ATP8 that begin with GTG and CCT respectively. Leu (L) and ser (S) were the most common abundant amino acids in the PCGs. The phylogenetic relationship and evolutionary distances were constructed by maximum likelihood approach using MEGA X software. The reported mitogenome was closely related to Mobula kuhlii (MKU MG10, KM364987) and Mobula eregoodootenkee (NC 025954).

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]