Ponente
Descripción
Resistance to conventional antibiotics is a critical problem worldwide with the maximal attention of the WHO that, nowadays, represents a serious challenge to the existence of humankind. Antimicrobial peptides are widely expressed in eukaryotic organisms and they constitute the main humoral innate response of invertebrates. Such peptides exhibit antimicrobial activity against bacteria, fungi, viruses, and parasites and they could be a supplemental or alternative for the treatment of infections. Cm-p5 is a cationic peptide derived from a coastal tropical snail, Cenchritis muricatus, that showed antifungal activity against human pathogens such as Candida albicans and other fungi. This peptide did not exhibit toxicity against mammalian cell lines in vitro and was structurally characterized by circular dichroism, polarimetry, and NMR spectroscopy, revealing an α-helical structure under conditions that mimic a cellular environment and a tendency to a random structure in aqueous solutions. The substitution of two amino acid residues in the structure of Cm-p5 by respective cysteines produced a stabilized cyclic derivative in its alpha-helical structure and two dimers by inter-monomeric bridges. The cyclic monomer increased its activity against Candida albicans and showed also activity against Candida parapsilosis. All three derivatives showed moderate activity against Pseudomonas aeruginosa, ESBL Klebsiella pneumoniae and Streptococcus agalactiae. They showed significant activity against Acinetobacter baumanii and Enterococcus faecium. The dimers had moderate activity against PA14 Pseudomonas aeruginosa. All three Cm-p5 derivatives inhibited activity against a virulent extracellular strain of Mycobacterium tuberculosis and Herpes Simplex Virus 2 in vitro. On the other hand, the derivatives had no effect on Zika Virus infection nor pseudo particles of SARS-CoV-2. Two peptides derived from the fluvial mollusk Pomacea poeyana were synthesized from the sequences obtained by MS-MS spectrometry contrasted in antimicrobial peptide databases. Pom-1 showed significant activity against Pseudomonas aeruginosa and moderate activity against Klebsiella pneumoniae and Listeria monocytogenes. All the peptides mentioned here were non-toxic in human cell cultures at concentrations that showed their antimicrobial activity.
