The green synthesis of silver nanoparticles (AgNPs) and their applications have attracted many researchers as the AgNPs are used effectively in targeting specific tissues and pathogenic microorganisms. The purpose of this study is to synthesize and characterize silver nanoparticles from fully expanded leaves of Eugenia roxburghii DC., as well as to test their effectiveness in inhibiting biofilm production. In this study, at 0.1 mM concentration of silver nitrate (AgNO3), stable AgNPs were synthesized and authenticated by monitoring the color change of the solution from yellow to brown, which was confirmed with spectrophotometric detection of optical density. The crystalline nature of these AgNPs was detected through an X-Ray Diffraction (XRD) pattern. AgNPs were characterized through a high-resolution transmission electron microscope (HR-TEM) to study the morphology and size of the nanoparticles (NPs). A new biological approach was undertaken through the Congo Red Agar (CRA) plate assay by using the synthesized AgNPs against biofilm production. The AgNPs effectively inhibit biofilm formation and the biofilm-producing bacterial colonies. This could be a significant achievement in contending with many dynamic pathogens.

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This study reported the first-ever de novo transcriptome analysis of Operculina turpethum, a high valued endangered medicinal plant, using the Illumina HiSeq 2500 platform. The de novo assembly generated a total of 64,259 unigenes and 20,870 CDS (coding sequence) with a mean length of 449 bp and 571 bp respectively. Further, 20,218 and 16,458 unigenes showed significant similarity with identified proteins of NR (non-redundant) and UniProt database respectively. The homology search carried out against publicly available database found the best match with Ipomoea nil sequences (82.6%). The KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis identified 6538 unigenes functionally assigned to 378 modules with phenylpropanoid biosynthesis pathway as the most enriched among the secondary metabolite biosynthesis pathway followed by terpenoid biosynthesis. A total of 17,444 DEGs were identified among which majority of the DEGs (Differentially Expressed Gene) involved in secondary metabolite biosynthesis were found to be significantly upregulated in stem as compared to root tissues. The qRT-PCR validation of 9 unigenes involved in phenylpropanoid and terpenoid biosynthesis also showed a similar expression pattern. This finding suggests that stem tissues, rather than root tissues, could be used to prevent uprooting of O. turpethum in the wild, paving the way for the plant's effective conservation. Moreover, the study formed a valuable repository of genetic information which will provide a baseline for further molecular research.

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Background: Caspase-8, a member of the family of conserved cysteine proteases, plays a crucial role in the initiation phase of the apoptotic death-signaling cascade and thereby attracts interest for its study across the animal species including fish. In India, rohu (Labeo rohita) is an important freshwater fish species; thus, this study on caspase-8 was undertaken to investigate its role during pathogenic invasion. Results: The complete cDNA sequence of Labeo rohita caspase-8 (Lrcasp8) consisted of 1746 bp nucleotides (nt) having an ORF of 1440 nt encoding a polypeptide of 480 amino acid (aa) residues with the molecular mass of ∼ 54.8 kDa. Structurally, Lrcasp8 comprised two DED domains (DED1 1-77aa and DED2 97-174aa ) and one CASc domain 230-476aa . Within the CASc domain, various putative motifs, viz., a large subunit (p20 237-360aa ), a small subunit (p10 389-474aa ), and a penta-peptide (QACQG 354-358aa ) active site, were identified. The secondary structure of Lrcasp8 protein comprised seventeen α-helices, eleven β-strands, and twenty-nine coils. Phylogenetically, it is closely related to common carp caspase-8 and exhibits significant (p < 0.05) similarity (88.3%) and identity (78.7 %) in their amino acid sequence. The tissue-specific expression of Lrcasp8 has been analyzed by quantitative real-time PCR assay, and it revealed the highest expression (~23-fold) in the blood and lowest in the spleen. In Aeromonas hydrophila and Edwardsiella tarda infection and rhabdovirus vaccination, caspase-8 gene expression in rohu fingerlings was significantly (p <0.05) induced in various organs/tissues. Infection of the Labeo rohita gill cells with A. hydrophila resulted in apoptosis and cell death with the induction of caspase-8 gene expression. Conclusion: This is the first report on the identification and structural characterization of caspase-8 cDNA and predicted protein and the analysis of caspase-8 gene expression in Labeo rohita following Aeromonas hydrophila and Edwardsiella tarda infections and rhabdovirus vaccinations. The data in this article together suggest the critical role of caspase-8 during infection and apoptosis in Labeo rohita.