No abstract

No abstract

Many antimicrobial peptides (AMPs) have multiple antimicrobial immunity effects. One such class of peptides is temporins. Temporins are the smallest (AMPs) found in nature and are highly active against gram-positive bacteria. Nowadays, there was a rapid increase in the availability of the 3D structure of proteins in PDB (protein data bank). The conserved residues and 3D structural conformations of temporins (AMPs) were still unknown. The present study explores the sequence analysis, alpha-helical structural conformations of temporins. The sequence of temporins was deracinated from APD3 database, the three-dimensional structure was constructed by homology modeling studies. The sequence analysis results show that the conserved residues among the peptide sequences, the maximum of the sequences are 70% alike to each other. The secondary structure prediction results revealed that 99% of temporin (AMPs) exhibited in alpha-helical form. The 3D structure speculated using RAMPAGE exposes the alpha-helical conformation in all temporins (AMPs). The phylogenetic analysis reveals the evolutionary relationships of temporins (AMPs), which are branched into seven clusters. As a result, we identified a list of potential temporin AMPs which docked to the antiviral protein (MERS-CoV), it shows good protein-peptide binding. This computational approach may serve as a good model for the rationale design of temporin based antibiotics.

No abstract

The triterpenoid, bauerenol, from Suregada angustifolia (Baill. ex Muell.-Arg.) Airy Shaw (Euphorbiaceae) was screened for anti-cancer property using hepatocellular carcinoma cell line, HepG2. Bauerenol exhibited growth inhibitory and apoptosis inducing potential against HepG2 cancer cells. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cytotoxic assay revealed that bauerenol treatment significantly reduced the growth of HepG2 cells in a time- and dose-dependent manner with 50% growth inhibitory concentration doses of 45 and 25 µg/mL at 24 and 48 h treatments, respectively. Bauerenol-induced cell death reflected apoptotic morphological features, that is, cell membrane blebbing, vacuolization, chromatin condensation, and nuclear fragmentation. In addition, bauerenol treatment diminished the mitochondrial membrane potential, by inducing the efflux of cytochrome c, downregulating the levels of anti-apoptotic Bcl-2 as well as upregulating the levels of pro-apoptotic Bax, and inducing caspase activation and poly (ADP-ribose) polymerase cleavage. Moreover, bauerenol treatment activates p38MAPK and inactivates the anti-apoptotic kinases Akt and ERK1/2 through the induction of reactive oxygen species. Furthermore, bauerenol-mediated S-phase arrest was associated with downregulation of cell cycle-rate-limiting factor (cyclin D1) and upregulation of cyclin-dependent kinase inhibitor p21 and tumor suppressor p53. Interestingly, pre-treatment of cells with reactive oxygen species inhibitor and p38 inhibitor significantly decreases bauerenol-induced cytotoxicity, Bax upregulation, and p38 activation. This study clearly states that bauerenol induces cell cycle arrest and apoptosis through the reactive oxygen species-dependent p38MAPK activation in HepG2 cancer cells.