Antibiotics
are miracle drugs that have saved millions of lives from microbial infections
since they were discovered in the 1940s. However, recent studies have shown
that bacteria have become increasingly resistant to antibiotics because of
misuse and abuse. Understanding how bacteria cause disease, how antibiotics
work, and how bacteria become resistant to these drugs is critical in the fight
against infectious diseases. Antimicrobial peptides (AMPs) isolated from the
venom of mygalomorph spiders were less investigated because taxonomists
hypothesized that AMPs evolved in araneomorph venoms after their separation
from mygalomorphs around 280 million years ago. Spider venom may represent a
potentially new source of novel antimicrobial agents that will act as pore
formers to increase permeability and to induce lysis of prokaryotic cells
leading to depolarization and cellular death. Our studies of natural peptides
from the mygalomorph spider Aphonopelma chalcodes
allowed
us to identify a specific peptide of mass 2920 Da with an antibacterial effect
both on S.
aureus and E. coli.
Based on electron micrographs of bacterial cells treated with this peptide, we
speculate that the mechanism of action could involve the peptide-lipid
interactions leading to either direct or indirect disruption and breakdown of
the cell membrane, leading to cell death. Innovative research to discover new
antibiotics, in addition to careful use of existing antibiotics, will help us
maintain the upper hand in the fight against microbial resistance
