Recent advances in antimicrobial peptide-based therapy.

Antimicrobial peptides (AMPs) are a group of polypeptide chains that have the property to target and kill a myriad of microbial organisms including viruses, bacteria, protists, etc. The first discovered AMP was named gramicidin, an extract of aerobic soil bacteria. Further studies discovered that these peptides are present not only in prokaryotes but in eukaryotes as well. They play a vital role in human innate immunity and wound repair. Consequently, they have maintained a high level of intrigue among scientists in the field of immunology, especially so with the rise of antibiotic-resistant pathogens decreasing the reliability of antibiotics in healthcare. While AMPs have promising potential to substitute for common antibiotics, their use as effective replacements is barred by certain limitations. First, they have the potential to be cytotoxic to human cells. Second, they are unstable in the blood due to action by various proteolytic agents and ions that cause their degradation. This review provides an overview of the mechanism of AMPs, their limitations, and developments in recent years that provide techniques to overcome those limitations. We also discuss the advantages and drawbacks of AMPs as a replacement for antibiotics as compared to other alternatives such as synthetically modified bacteriophages, traditional medicine, and probiotics.

Recent progress in biomarker-based diagnostics of Helicobacter pylori, gastric cancer-causing bacteria.

The progression of any disease and its outcomes depend on the complicated interaction between pathogens, host and environmental factors. Thus, complete knowledge of bacterial toxins involved in pathogenesis is necessary to develop diagnostic methods and alternative therapies, including vaccines. This review summarizes recently employed biomarkers to diagnose the presence of Helicobacter pylori bacteria. The authors review distinct types of disease-associated biomarkers such as urease, DNA, miRNA, aptamers and bacteriophages that can be utilized as targets to detect Helicobacter pylori and, moreover, gastric cancer in its early stage. A detailed explanation is also given in the context of the recent utilization of these biomarkers in the development of a highly specific and sensitive biosensing platform.

An overview of adjuvants utilized in prophylactic vaccine formulation as immunomodulators.

INTRODUCTION: Development of efficient and cost effective vaccines have been recognized as the primary concern to improve the overall healthcare in a country. In order to achieve this goal, more improved and powerful adjuvants need to be developed. Lacking in the self-adjuvanting immuno-modulatory constituents, vaccines exhibit lower immunogenicity. Combining potent adjuvants with vaccines is the most appropriate method to enhance the efficacy of the vaccines. Hence, this review is focussed on the most potent adjuvants for the formulation of vaccines. Areas covered: This review focuses on Oil-based emulsions, Mineral compounds, Liposomes, Bacterial products, ISCOMs and most recently used nanomaterials as adjuvants for enhancing the antigenicity of vaccines. Furthermore, this review explains the immunological response elicited by various particles. Moreover, case studies are incorporated providing an in depth analyses of various adjuvant-containing vaccines which are currently used. Expert commentary: Enhanced fundamental knowledge about the adjuvants and their immuno-stimulatory capabilities and delivery mechanisms will facilitate the rational designing of prophylactic vaccines with better efficacy.

Effects of cholesterol on Helicobacter pylori growth and virulence properties in vitro.

BACKGROUND: Colonization of the gastric mucosa by Helicobacter pylori is often associated with chronic gastric pathologies in humans. Development of disease correlates with the presence of distinct bacterial pathogenicity factors, such as the cag type IV secretion system (cag-T4SS), the vacuolating cytotoxin (VacA), or the ability of the bacteria to acquire and incorporate cholesterol from human tissue. MATERIALS AND METHODS: The in vitro growth of H. pylori requires media (Brucella broth) complemented with vitamins and horse serum or cyclodextrins, prepared as blood agar plates or liquid cultures. Liquid cultures usually show a slow growth. Here, we describe the successful growth of H. pylori strains 26695, P217, P12, and 60190 on serum-free media replacing serum components or cyclodextrins with a commercially available cholesterol solution. RESULTS: The effects of cholesterol as a substitute for serum or cyclodextrin were rigorously tested for growth of H. pylori on agar plates in vitro, for its general effects on bacterial protein synthesis (the proteome level), for H. pylori's natural competence and plasmid DNA transfer, for the production of VacA, and the general function of the cag-pathogenicity island and its encoded cag-T4SS. Generally, growth of H. pylori with cholesterol instead of serum supplementation did not reveal any restrictions in the physiology and functionality of the bacteria except for strain 26695 showing a reduced growth on cholesterol media, whereas strain 60190 grew more efficient in cholesterol- versus serum-supplemented liquid medium. CONCLUSIONS: The use of cholesterol represents a considerable option to serum complementation of growth media for in vitro growth of H. pylori.