Deciphering the role of microRNA - A step by step guide.

MicroRNAs (miRNAs), are small non-coding RNAs of approximately 22 nucleotides in length, playing an important role in regulating gene expression post-transcriptionally. Understanding the effect of miRNA regulation in a pathway-specific manner unravels the approaches adopted to apprehend biological mechanisms, the information, which is scanty for researchers, not primed already for miR related research. Here, we describe a quick perspective in 5 steps with probable approaches and assays at every level to unravel the specific role of a microRNA, miR-145a-5p, as an example. This perspective as a guide would help in identifying novel targets for a microRNA, as shown for miR-145a-5p, which down-regulated the mRNA expression of ADD3 and BRCA2, using bioinformatic tools and experimental assays.

Laterosporulin10: a novel defensin like Class IId bacteriocin from Brevibacillus sp. strain SKDU10 with inhibitory activity against microbial pathogens.

Bacteriocins are antimicrobial peptides (AMPs) produced by bacteria to acquire survival benefits during competitive inter- and intra-species interactions in complex ecosystems. In this study, an AMP-producing soil bacterial strain designated SKDU10 was isolated and identified as a member of the genus Brevibacillus. The AMP produced by strain SKDU10 identified as a class IId bacteriocin with 57.6 % homology to laterosporulin, a defensin-like class IId bacteriocin. However, substantial differences were observed in the antimicrobial activity spectrum of this bacteriocin named laterosporulin10 when compared to laterosporulin. Laterosporulin10 effectively inhibited the growth of Staphylococcus aureus and Mycobacterium tuberculosis (Mtb H37Rv) with LD50 values of 4.0 µM and 0.5 µM, respectively. Furthermore, laterosporulin10 inhibited the growth of Mtb H37Rv strain at about 20 times lower MIC value compared to S. aureus MTCC 1430 or M. smegmatis MC2 155 in vitro and ex vivo. Electron micrographs along with membrane permeabilization studies using FACS analysis revealed that laterosporulin10 is a membrane-permeabilizing peptide. Interestingly, laterosporulin10 was able to efficiently kill Mtb H37Rv strain residing inside the macrophages and did not show haemolysis up to 40 µM concentration.