Bacteriocin PJ4 Active Against Enteric Pathogen Produced by Lactobacillus helveticus PJ4 Isolated from Gut Microflora of Wistar Rat (Rattus norvegicus): Partial Purification and Characterization of Bacteriocin

The increase of multidrug-resistant pathogens and the restriction on the use antibiotics due to its side effects have drawn attention to the search for possible alternatives. Bacteriocins are small antimicrobial peptides produced by numerous bacteria. Much interest has been focused on bacteriocins because they exhibit inhibitory activity against pathogens. Lactic acid bacteria possess the ability to synthesize antimicrobial compounds (like bacteriocin) during their growth. In this study, an antibacterial substance (bacteriocin PJ4) produced by Lactobacillus helveticus PJ4, isolated from rat gut microflora, was identified as bacteriocin. It was effective against wide assay of both Gram-positive and Gram-negative bacteria involved in various diseases, including Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Enterococcus faecalis, and Staphylococcus aureus. The antimicrobial peptide was relatively heat-resistant and also active over a wide pH range of 2–10. It has been partially purified to homogeneity using ammonium sulfate precipitation and size exclusion chromatography and checked on reverse-phase high-performance liquid chromatography. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis of bacteriocin PJ4 purified through size exclusion chromatography resolved ~6.5 kDa protein with bacteriocin activity. The peptide is inactivated by proteolytic enzymes, trypsin, and lipase but not when treated with catalase, α-amylase, and pepsin. It showed a bactericidal mode of action against the indicator strains E. coli MTCC443, Lactobacillus casei MTCC1423, and E. faecalis DT48. Such characteristics indicate that this bacteriocin may be a potential candidate for alternative agents to control important pathogens.     

Metal porphyrins as electrocatalysts for commercially important reactions

Transition Metal Chemistry -     

Entrapment of Elusive Guests within Metal‐Seamed Nanocapsules

Anions play a crucial role in locking alkali metals on the interior of metal–organic capsules that contain structural water gates. This role is further evidenced when stitching‐up the capsule seam, resulting in either expulsion or trapping of cesium ions depending on the anion employed.     

Solution-Phase and Magnetic Approach towards Understanding Iron Gall Ink-like Nanoassemblies

Metal-containing tubes: The structures of several iron-containing C-methylpyrogallol[4]arene (PgC(1) ) nanoassemblies were studied in both the solid and solution phases. The nanoassemblies have a tubular architecture with the iron as part of the framework (see picture; gray C, red O, turquoise/blue Fe), and magnetic analysis suggests a canted or spiral arrangement of the iron centers.