RESUMO

One of the biggest challenges faced presently by clinicians is the emergence of multidrug -resistant pathogens that can infect humans and animals. To control the infections caused by such pathogens the development of new drugs is required. Bacteria are a rich source of ribosomally -synthesized antimicrobial peptides known as bacteriocins, which are characterized by the presence of a self-defense immunity system. Labionin-containing lantibiotics and sactibiotics are posttranslationally modified bacteriocins with peculiar features. Labionin-containing peptides belong to subclass Ic lantibiotics in which the carbacyclic triamino triacid labionin, a structural variant of lanthionine, and a methyl-substitute labionin derivative are found, giving the molecule a labyrinthine structure. Sactibiotics are circular or linear peptides belonging to a distinct bacteriocin class (class V) which is characterized by the presence of cross-linkages formed by the thiol group of cysteine residues and the α-carbon of acceptor amino acids. A few examples of these bacteriocins have been described in the literature to date, although putative gene clusters with the potential to encode such peptides can be found in the genome of many bacterial species. Some peptides already under study exhibit potential biotechnological applications because of their remarkable antibacterial or antiviral activities, as well as their analgesic activity. Therefore, in this review, the main findings concerning these peptides will be addressed and discussed, with an emphasis on their potential use in clinical settings.

Assuntos

Antibacterianos/química , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Antivirais/farmacologia , Bactérias/efeitos dos fármacos , Vírus/efeitos dos fármacos , Animais , Antivirais/química , Humanos , Testes de Sensibilidade Microbiana

RESUMO

This report demonstrates the usefulness of PCR for the genes spaS and sboA as a means of identifying Bacillus strains with a potential to produce subtilin and subtilosin A. One collection strain and five Bacillus spp. isolated from aquatic environments in the Amazon basin were screened by PCR using primers for sboA and spaS designed specifically for this study. The sequences of the PCR products showed elevated homology with previously described spaS and sboA genes. Antimicrobial peptides were isolated from culture supernatants and analyzed by mass spectrometry. For all samples, the mass spectra revealed clusters with peaks at m/z 3300-3500 Da, corresponding to subtilosin A, subtilin and isoforms of these peptides. These results suggest that the antimicrobial activity of these strains may be associated with the production of subtilosin A and/or subtilin. The PCR used here was efficient in identifying novel Bacillus strains with the essential genes for producing subtilosin A and subtilin.