Anupam Roy

Challenges and future prospects of antibiotic therapy: From peptides to phages utilization

Bacterial infections are raising serious concern across the globe. The effectiveness of conventional antibiotics is decreasing due to global emergence of multi-drug-resistant (MDR) bacterial pathogens. This process seems to be primarily caused by an indiscriminate and inappropriate use of antibiotics in non-infected patients and in the food industry. New classes of antibiotics with different actions against MDR pathogens need to be developed urgently. In this context, this review focuses on several ways and future directions to search for the next generation of safe and effective antibiotics compounds including antimicrobial peptides, phage therapy, phytochemicals, metalloantibiotics, lipopolysaccharide, and efflux pump inhibitors to control the infections caused by MDR pathogens.

Purification, biochemical characterization and self-assembled structure of a fengycin-like antifungal peptide from Bacillus thuringiensis strain SM1

An antifungal lipopeptide fengycin, producing strain SM1 was isolated from farm land soil sample and identified as Bacillus thuringiensis strain SM1 by using 16S rDNA analysis. Fengycin detected in the culture extract was further purified using HPLC and showed a molecular mass of 1492.8 Da by MALDI-TOF-MS analysis. Purified fengycin was allowed to construct their self-assembled structure onto a hydrophobic surface showing a clear improvement of antibacterial activity. In self-assembly, fengycin adapts a spherical micelle core shell like structure. Self-assembled fengycin may be a successful antimicrobial compound modifying its action from confined antifungal function. Besides it can open up a new area of research in supramolecular lipopeptide based compound making. This can revealed the mode of action of this unique self-assembled structure to fully evaluate its potential for use as an antimicrobial drug to control the emergence of bacterial infection.

Biomedical Exploitation of Self Assembled Peptide Based Nanostructures

Nowadays, peptide based disease prevention is an important topic in biomedical science, which may radically change the traditional use of biomaterials and improve the life quality. Self-assembled nanostructured peptides have been receiving extreme attention in the drug delivery field due their high biocompatibility levels, better loading capacity, extended circulation and localization in required target site. This article focuses on the composition and synthesis of different forms of self-assembled peptide nanostructures as nanotubes, nanofibers, nanoparticles, nanotapes and nanogels. The most important properties for their self assembled mechanism and their biomedical applications are also discussed. Various potential applications of nanostructures peptide could be developed designed for therapeutic agents delivery, biosensors, anticancerous and antimicrobial activities.

Functional and structural insights on self-assembled nanofiber-based novel antibacterial ointment from antimicrobial peptides, bacitracin and gramicidin S

A novel antibacterial ointment using bacitracin, specific for Gram-positive bacteria, and gramicidin S, a highly toxic antibacterial peptide, was here developed showing broad-spectrum antibacterial activities against pathogenic strains with less toxicity after self-assembly into nanofiber structures. Such structures were confirmed with scanning electron microscopy and CD analyses. In addition, in silico studies using docking associated with molecular dynamics were carried out to obtain information about fiber structural oligomerization. Thus, the bacitracin and gramicidin S-based self-assembled nanopeptide ribbon may be a successful ointment formulation for bacterial infection control.

Self-assembled carbohydrate nanostructures: synthesis strategies to functional application in food

Self-assembled carbohydrate nanostructures are drawing research attention due to high biocompatibility levels and potentiality to be used in several functional applications ranging from drug delivery to functional food. In this chapter efforts are made to provide an outline of the recent advancement of carbohydrate-based self-assembly strategies for food applications. A discussion of assembling strategies, behavior, and structure–function relationship associated with varying shapes and sizes is done to give broader direction to assembly strategy, its enhancement and control. Different self-assembly strategies with the food applications will help and appeal to people working in developing self-assembled functional biomaterials for food applications.

Fungi Fights Fungi: Tip-off in Antifungal Chemotherapy

Fungal infections have taken a new spectrum due to the increased incidence of multi-drug resistant fungal pathogens. Freedom of choice for drugs to treat fungal infections is also narrow because of lesser probability of discovering drugs that would bypass affecting human cells and target fungal cells producing fewer side effects in patients. An approach has gained prominence in research is to look for bioactive antifungal compounds from natural sources and discover new classes of antifungals to control the recent emergence of fungal infections. Most of antifungal drugs are originated from fungi. A conservative estimate of total number of fungal species on this planet would exceed 106 if taken into account the ones yet to be discovered from diverse habitats ranging from forest land to marine ecosystem. While attempting to summarize the status of reported fungi-derived antifungal compounds discovered since ancient times, the subset of such compounds were found to be anticancer too. Antifungal compounds with the promise of inducing challenge to rediscover the new effective molecules from drug prototype are also discussed.

Crede’s method in eye water finds a nanomedicine base: a potential candidate to control ophthalmia neonatorum

Abstract Lethal eye infections of newborns occur mostly due to their passage through the contaminated birth canal. In the pre-antibiotic era blindness from such infections was most challenging. This scenario changed after the 1880s with the use of Crede’s method (a drop of 2.0% silver nitrate solution into newborn’s eyes which was later reduced to 1.0%). This research is focused on finding the structure-function relationship between silver nitrate and tears which offer antimicrobial action. A reinvestigation of Crede’s method revealed a light-dependent instant formation of silver oxide nanoparticles (sizes 20–70 nm) with strong antimicrobial action against ocular pathogens. Nano-therapy would be the key reason behind the widely accepted use of silver nitrate eye drop as a prophylactic agent prior to the discovery of antibiotics. A scientific view on the age-old Crede’s method explores the use of nano-therapy as a prophylactic agent. When routine prophylaxis with topical antibiotics brings the risk of resistance, Crede’s method may, in the near future, offer a way to fight against ophthalmia neonatorum (ON) caused by antibiotic-resistant pathogens.