Bioactive Peptides and Their Antibiotic Activity

A special issue of Antibiotics (ISSN 2079-6382). This special issue belongs to the section "Antimicrobial Peptides".

Deadline for manuscript submissions: 30 November 2025 | Viewed by 11259

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Associate Professor, School of Pharmaceutical Sciences of Ribeirao Preto, University of Sao Paulo, CEP, Ribeirao Preto 14040-903, SP, Brazil
Interests: bioactive peptides; cancer; natural peptides; molecular biology; proteases and proteomic
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Special Issue Information

Dear Colleagues,

The polypeptide chains of peptides with antimicrobial activity generally have fifty or fewer amino acid residues. Depending on the composition of the amino acids that make up the polypeptide chain, antimicrobial peptides can have cationic, anionic, and/or aromatic charged in addition to their characteristic size and conformation. [1]. Antimicrobial peptides (AMPs) are conserved biomolecules, and are part of the defense systems of many organisms, from prokaryotes to multicellular organisms such as humans [2]. AMPs are produced by organisms as a defense mechanism against pathogenic microbes. Initial studies on defense peptides identified defensins, cecropins, retropins and cathelicidins, which have different structures and bioactivities [3]. Antimicrobial peptides can be classified according to their source (animal, plant, microbial, insect, amphibian, aquatic), and by their structure (α-helix, β-sheet, both α-helix and β-sheet, linear). They are also classified based on species rich in amino acids (especially Gly, Arg, Pro, His and Trp), and depending on their activity (e.g., antimicrobial, antiviral, antiparasitic, antifungal, anti-inflammatory and anticancer) [4]. The first reported AMP was gramicidin, isolated from Bacillus brevis in 1939. Defensin, another AMP, was isolated from rabbit leukocytes. Since the 1960s, there has been a great interest in these peptides, and more than 5000 AMPs have been reported [1]. Thus, peptides are considered promising molecules not only for application as antimicrobial therapy, but also in immunomodulatory, anticancer, antioxidant and other applications [5]. Currently, many in silico analysis methods have been helping to target peptides for antimicrobial applications. Molecular biology techniques associated with bioinformatics are also providing good results in obtaining more effective AMPs.

References

[1] Cardoso, P., Glossop, H., Meikle, T. G., Aburto-Medina, A., Conn, C. E., Sarojini, V., Valery, C. Molecular engineering of antimicrobial peptides: microbial targets, peptide motifs and translation opportunities. Biophysical Reviews, 2021, vol. 13, p.35–69, https://doi.org/10.1007/s12551-021-00784-y.

[2] Ebenhan, T., Gheysens, O., Kruger, H. G., Zeevaart, J. R., Sathekge, M. M. Antimicrobial peptides: their role as infection-selective tracers for molecular imaging. Biomed Research International, 2014, Article ID, 867381, p.1-15. https://doi.org/10.1155/2014/867381.

[3] Fjell, C. D., Hiss, J. A., Hancock, R. E. W., Schneider, G. Designing antimicrobial peptides: form follows function. Nature Reviews Drug Discovery, Vol. 11, January 2012, p.37-51. https://doi.org/10.1038/nrd3591.

[4] Huan, Y., Kong, Q., Mou, H., Yi, H. Antimicrobial Peptides: Classification, Design, Application and Research Progress in Multiple Fields. Frontiers in Microbiology, 2020, vol. 11 October 2020, p. 1-21, ID Article 582779, https://doi.org/10.3389/fmicb.2020.582779.

[5] Torres, M. D. T., Sothiselvam, S., Lu, T. K. and de la Fuente-Nunez C. Peptide Design Principles for Antimicrobial Applications. Journal of Molecular Biology, 2019, Vol. 431, p. 3547–3567, https://doi.org/10.1016/j.jmb.2018.12.015.

Dr. Hamilton Cabral
Guest Editor

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Keywords

  • database peptides
  • therapeutic agents
  • peptide design
  • antimicrobial peptides
  • antibiotic resistance
  • therapeutic drugs

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Published Papers (7 papers)

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Research

16 pages, 422 KiB  
Article
Antimicrobial Peptides SET-M33L and SET-M33L-PEG Are Promising Agents Against Strong Biofilm-Forming P. aeruginosa, Including Multidrug-Resistant Isolates
by Alessio Fontanot, Peter D. Croughs, Clelia Cortese, Adrianus C. J. M. de Bruijn, Chiara Falciani, Alessandro Pini, Isabella Ellinger, Wendy W. J. Unger and John P. Hays
Antibiotics 2025, 14(7), 699; https://doi.org/10.3390/antibiotics14070699 - 11 Jul 2025
Viewed by 379
Abstract
Background: The antimicrobial peptides (AMPs) SET-M33L and SET-M33L-PEG were investigated against 10 clinical isolates of P. aeruginosa. Methods: Their minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), and minimum biofilm inhibitory concentrations (MBICs) were evaluated against tobramycin, ceftazidime, and polymyxin [...] Read more.
Background: The antimicrobial peptides (AMPs) SET-M33L and SET-M33L-PEG were investigated against 10 clinical isolates of P. aeruginosa. Methods: Their minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), and minimum biofilm inhibitory concentrations (MBICs) were evaluated against tobramycin, ceftazidime, and polymyxin B. Results: MICs and MBCs were 7- to 100-fold lower than tobramycin, and 10- to 300-fold lower than ceftazidime. Fractional inhibitory concentration (FIC) indices showed an additive effect, while fractional bactericidal concentration (FBC) indices showed synergistic effects (FBC < 0.5) for most isolates. Conclusion: SET-M33L and SET-M33L-PEG are promising antimicrobial agents against strong biofilm-forming P. aeruginosa, including MDR isolates. Full article
(This article belongs to the Special Issue Bioactive Peptides and Their Antibiotic Activity)
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17 pages, 572 KiB  
Article
Synthetic Human Lactoferrin Peptide hLF(1-11) Shows Antifungal Activity and Synergism with Fluconazole and Anidulafungin Towards Candida albicans and Various Non-Albicans Candida Species, Including Candidozyma auris
by Carlo Brouwer, Youp van der Linden, Maria Rios Carrasco, Saleh Alwasel, Tarad Abalkhail, Fatimah O. Al-Otibi, Teun Boekhout and Mick M. Welling
Antibiotics 2025, 14(7), 671; https://doi.org/10.3390/antibiotics14070671 - 2 Jul 2025
Viewed by 471
Abstract
Introduction: Candidozyma auris (Cz. auris) has emerged globally, and diseases caused by it are associated with a mortality rate of 30–72%. This yeast is often multidrug-resistant and challenging to treat. A synthetic peptide, consisting of 11 amino acids of human lactoferrin [...] Read more.
Introduction: Candidozyma auris (Cz. auris) has emerged globally, and diseases caused by it are associated with a mortality rate of 30–72%. This yeast is often multidrug-resistant and challenging to treat. A synthetic peptide, consisting of 11 amino acids of human lactoferrin (hLF1-11), offers a new therapy that is active against Candida albicans, non-albicans Candida yeasts, as well as Cz. auris. The current study examined the susceptibility of clinically relevant Candida species to hLF(1-11) in vitro and investigated the synergistic interaction of this peptide with fluconazole (FLU) and anidulafungin (ANI). Methods: Susceptibility of the yeasts to hLF(1-11) was tested with a microdilution method to determine minimum inhibitory concentrations (MICs). A total of 59 strains belonging to 16 species of Candida or Candidozyma were tested. The treatment cohort included 20 strains of Cz. auris originating from six different countries. Results: Mean MIC values of all susceptible strains ranged from 16.66 ± 6.46 μg/mL to 45.83 ± 10.21 μg/mL. There were no statistical differences in the susceptibility of hLF(1-11) for Cz. auris across geographic origins. In the combinatory tests, drugs acting together, the fractional inhibitory concentration indexes [FIC] < 1.0, showed a synergistic or additive effect on the efficacy of FLU and ANI when used in combination with hLF(1-11). [FIC] indexes 1–2 were interpreted as intermediate. MIC values in combinatory use were 1–2 titer steps lower than when used alone. Conclusions: hLF(1-11) inhibits the growth of yeasts that belong to the genus Candida, including Cz. auris. The combinatory use may be further investigated to treat infections caused by resistant yeasts. Full article
(This article belongs to the Special Issue Bioactive Peptides and Their Antibiotic Activity)
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12 pages, 1013 KiB  
Article
Potential Inhibitory Effect of the Peptide Melittin Purified from Apis mellifera Venom on CTX-M-Type Extended-Spectrum β-Lactamases of Escherichia coli
by Sheril Ramos-Alcántara, María Alejandra Cornejo Napan, Giovanni Lopez Campana and Jesus Tamariz
Antibiotics 2025, 14(4), 403; https://doi.org/10.3390/antibiotics14040403 - 14 Apr 2025
Viewed by 710
Abstract
Background. Extended-spectrum β-lactamases (ESBLs) hydrolyze nearly all β-lactam antibiotics, affecting one of the most important groups of antimicrobials used in Gram-negative infections. Among them, CTX-M is the most widespread type of ESBL. This study aimed to evaluate the hydrolytic activity of CTX-M-type ESBLs [...] Read more.
Background. Extended-spectrum β-lactamases (ESBLs) hydrolyze nearly all β-lactam antibiotics, affecting one of the most important groups of antimicrobials used in Gram-negative infections. Among them, CTX-M is the most widespread type of ESBL. This study aimed to evaluate the hydrolytic activity of CTX-M-type ESBLs following exposure to the antimicrobial peptide Melittin. Methods. Melittin was purified from Apis mellifera venom through ultrafiltration and characterized by SDS-PAGE. The minimum inhibitory concentration (MIC) of Melittin against ESBL-producing E. coli was determined by the broth microdilution method. The inhibition of ESBL’s hydrolytic activity following exposure to sub-MIC doses of Melittin was quantified using a kinetic assay based on hydrolyzed nitrocefin. Additionally, the effect of Melittin on the expression of the blaCTX-M gene was evaluated via RT-PCR. Results. The peptide fraction of Apitoxin smaller than 10 kDa exhibited a protein band corresponding to Melittin, devoid of higher molecular weight proteins. The MIC of Melittin ranged from 50 to 80 µg/mL. Exposure to Melittin at sub-MIC doses significantly inhibited ESBL hydrolytic activity, reducing it by up to 67%. However, the transcription of the blaCTX-M gene in the presence of Melittin revealed no significant changes. Conclusions. Melittin is able to inhibit ESBL’s hydrolytic activity but not blaCTX-M transcription possibly indicating an effect at the translational or post-translational level. Full article
(This article belongs to the Special Issue Bioactive Peptides and Their Antibiotic Activity)
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11 pages, 2016 KiB  
Article
Fusion Partner Facilitates Expression of Cell-Penetrating Peptide L2 in Pichia pastoris
by Xuan Li, Na Yang, Yuxin Fang, Ruoyu Mao, Ya Hao, Da Teng, Na Dong, Anshan Shan and Jianhua Wang
Antibiotics 2024, 13(12), 1207; https://doi.org/10.3390/antibiotics13121207 - 11 Dec 2024
Cited by 2 | Viewed by 1350
Abstract
Background: L2 is formed by combining the pheromone of Streptococcus agalactiae (S. agalactiae) and a cell-penetrating peptide (CPP) with cell-penetrating selectivity. L2 has more significant penetration and better specificity for killing S. agalactiae. However, the production of AMPs by chemical [...] Read more.
Background: L2 is formed by combining the pheromone of Streptococcus agalactiae (S. agalactiae) and a cell-penetrating peptide (CPP) with cell-penetrating selectivity. L2 has more significant penetration and better specificity for killing S. agalactiae. However, the production of AMPs by chemical synthesis is always a challenge because of the production cost. Methods: This study was devoted to the heterologous expression of the cell-penetrating peptide L2 in Pichia pastoris using SUMO and a short acidic fusion tag as fusion partners, and the high-density expression of SUMO-L2 was achieved in a 5 L fermenter. Results: The results showed that SUMO-L2 expression in the 5 L fermenter reached 629 mg/L. The antibacterial activity of recombinant L2 was examined; the minimum inhibitory concentration (MICs) and minimum bactericidal concentration (MBCs) of purified L2 were 4–8 μg/mL and 8–16 μg/mL against S. agalactiae after 84 h of lysis with 50% formic acid. Conclusions: The findings suggest that SUMO is a suitable fusion tag to express cell-penetrating peptide L2. Full article
(This article belongs to the Special Issue Bioactive Peptides and Their Antibiotic Activity)
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20 pages, 6008 KiB  
Article
Peptidome Profiling of Bubalus bubalis Urine and Assessment of Its Antimicrobial Activity against Mastitis-Causing Pathogens
by Rohit Kumar, Nikunj Tyagi, Anju Nagpal, Jai Kumar Kaushik, Ashok Kumar Mohanty and Sudarshan Kumar
Antibiotics 2024, 13(4), 299; https://doi.org/10.3390/antibiotics13040299 - 26 Mar 2024
Cited by 1 | Viewed by 2222
Abstract
Urinary proteins have been studied quite exhaustively in the past, however, the small sized peptides have remained neglected for a long time in dairy cattle. These peptides are the products of systemic protein turnover, which are excreted out of the body and hence [...] Read more.
Urinary proteins have been studied quite exhaustively in the past, however, the small sized peptides have remained neglected for a long time in dairy cattle. These peptides are the products of systemic protein turnover, which are excreted out of the body and hence can serve as an important biomarker for various pathophysiologies. These peptides in other species of bovine have been reported to possess several bioactive properties. To investigate the urinary peptides in buffalo and simultaneously their bioactivities, we generated a peptidome profile from the urine of Murrah Buffaloes (n = 10). Urine samples were processed using <10 kDa MWCO filter and filtrate obtained was used for peptide extraction using Solid Phase Extraction (SPE). The nLC-MS/MS of the aqueous phase from ten animals resulted in the identification of 8165 peptides originating from 6041 parent proteins. We further analyzed these peptide sequences to identify bioactive peptides and classify them into anti-cancerous, anti-hypertensive, anti-microbial, and anti-inflammatory groups with a special emphasis on antimicrobial properties. With this in mind, we simultaneously conducted experiments to evaluate the antimicrobial properties of urinary aqueous extract on three pathogenic bacterial strains: S. aureus, E. coli, and S. agalactiae. The urinary peptides observed in the study are the result of the activity of possibly 76 proteases. The GO of these proteases showed the significant enrichment of the antibacterial peptide production. The total urinary peptide showed antimicrobial activity against the aforementioned pathogenic bacterial strains with no significant inhibitory effects against a buffalo mammary epithelial cell line. Just like our previous study in cows, the present study suggests the prime role of the antimicrobial peptides in the maintenance of the sterility of the urinary tract in buffalo by virtue of their amino acid composition. Full article
(This article belongs to the Special Issue Bioactive Peptides and Their Antibiotic Activity)
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18 pages, 3998 KiB  
Article
Expression of the Antimicrobial Peptide SE-33-A2P, a Modified Analog of Cathelicidin, and an Analysis of Its Properties
by Vagif Gasanov, Ekaterina Vorotelyak and Andrey Vasiliev
Antibiotics 2024, 13(2), 190; https://doi.org/10.3390/antibiotics13020190 - 16 Feb 2024
Cited by 4 | Viewed by 2418
Abstract
In this study, we developed a method for the expression of the antimicrobial peptide SE-33-A2P in E. coli bacterial cells. The SE-33-A2P peptide consists of A2P and SE-33 peptides and is a retro analog of cathelicidin possessing antimicrobial activity against both Gram-positive and [...] Read more.
In this study, we developed a method for the expression of the antimicrobial peptide SE-33-A2P in E. coli bacterial cells. The SE-33-A2P peptide consists of A2P and SE-33 peptides and is a retro analog of cathelicidin possessing antimicrobial activity against both Gram-positive and Gram-negative bacteria. Furthermore, the A2P peptide is a self-cleaving peptide. For an efficient expression of the SE-33-A2P peptide, a gene encoding several repetitive sequences of the SE-33 peptide separated by A2P sequences was created. The gene was cloned into a plasmid, with which E. coli cells were transformed. An induction of the product expression was carried out by IPTG after the cell culture gained high density. The inducible expression product, due to the properties of the A2P peptide, was cleaved in the cell into SE-33-A2P peptides. As the next step, the SE-33-A2P peptide was purified using filtration and chromatography. Its activity against both Gram-positive and Gram-negative bacteria, including antibiotic-resistant bacteria, was proved. The developed approach for obtaining a prokaryotic system for the expression of a highly active antimicrobial peptide expands the opportunities for producing antimicrobial peptides via industrial methods. Full article
(This article belongs to the Special Issue Bioactive Peptides and Their Antibiotic Activity)
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28 pages, 1897 KiB  
Article
Tuning the Anthranilamide Peptidomimetic Design to Selectively Target Planktonic Bacteria and Biofilm
by Rajesh Kuppusamy, Muhammad Yasir, Tsz Tin Yu, Florida Voli, Orazio Vittorio, Michael J. Miller, Peter Lewis, David StC Black, Mark Willcox and Naresh Kumar
Antibiotics 2023, 12(3), 585; https://doi.org/10.3390/antibiotics12030585 - 15 Mar 2023
Cited by 6 | Viewed by 2727
Abstract
There is a pressing need to develop new antimicrobials to help combat the increase in antibiotic resistance that is occurring worldwide. In the current research, short amphiphilic antibacterial and antibiofilm agents were produced by tuning the hydrophobic and cationic groups of anthranilamide peptidomimetics. [...] Read more.
There is a pressing need to develop new antimicrobials to help combat the increase in antibiotic resistance that is occurring worldwide. In the current research, short amphiphilic antibacterial and antibiofilm agents were produced by tuning the hydrophobic and cationic groups of anthranilamide peptidomimetics. The attachment of a lysine cationic group at the tail position increased activity against E. coli by >16-fold (from >125 μM to 15.6 μM) and greatly reduced cytotoxicity against mammalian cells (from ≤20 μM to ≥150 μM). These compounds showed significant disruption of preformed biofilms of S. aureus at micromolar concentrations. Full article
(This article belongs to the Special Issue Bioactive Peptides and Their Antibiotic Activity)
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