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Bat Cathelicidins as Natural Antimicrobial Agents: A Computational and In Vitro Investigation
1 , 2 , 2 , 2, 3 , 2, 3 , 2, 3 , 2, 4 , * 2
1  Macromolecules Biotechnology Research Group, Institute of Natural Products and Agrobiology (IPNA-CSIC), San Cristóbal de La Laguna, Spain
2  Macromolecules Biotechnology Research Group, Institute of Natural Products and Agrobiology (IPNA-CSIC), San Cristóbal de La Laguna, Spain.
3  Escuela de Doctorado y Estudios de Posgrado, Universidad de La Laguna, San Cristóbal de La Laguna, Spain.
4  Current address: Animal Production and Biotechnology Group, Institute of Animal Health and Food Safety, University of Las Palmas de Gran Canaria, Spain.
Academic Editor: Guangshun Wang

Published: 12 October 2023 by MDPI in Antimicrobial Peptides: Yesterday, Today and Tomorrow session Other Topics (registering DOI)

Antimicrobial peptides (AMPs) are small proteins that play an important role in the innate immune system of various organisms, including plants, animals, and humans. These natural defence molecules have attracted considerable interest due to their potential as alternative antimicrobial agents to combat infectious diseases. In this study, we used computational and in vitro methods to investigate the antimicrobial activity of cathelicidin family peptides from bat species with different ecological niches.

The study of the physicochemical parameters of the peptides (hydrophobicity and net charge), together with the study of the helical regions, allowed us to deduce the antimicrobial character of peptides. To analyse the antimicrobial activity in vitro, we first determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against four different bacteria: E. coli, Salmonella, S. aureus, and E. faecalis. We then selected the most effective peptide and assessed whether it acts as a bacteriostatic or bactericidal agent. Additionally, we investigated the duration of its activity and its ability to lyse bacterial cells. We accomplished this by plotting killing curves during both the exponential and latent phases of bacterial growth. Finally, we evaluated the peptide's potential to cause hemolysis in rat erythrocytes. 105

One of our peptides revealed a high antimicrobial activity, with MIC and MBC values ranging from 3.12 to 1.56 μM. It also demonstrated bactericidal properties during the stationary phase but acted as a bacteriostatic agent during the exponential phase. Notably, it exhibited lytic activity against the tested bacteria but no hemolytic activity against rat erythrocytes.

Keywords: Bat cathelicidins; minimum bactericidal concentration; minimum inhibitory concentration; killing curves; hemolysis activity