Search Results (1,061)

The growing problem of antimicrobial resistance in aquaculture, caused by the excessive and unregulated use of antibiotics, highlights the critical necessity for developing new anti-infective solutions. Based on the characteristics of glycine-rich antimicrobial peptides (AMPs) and transcriptomic data, an antimicrobial peptide, namely AfRgly1, was discovered in this study. Subsequently, the peptide was obtained through heterologous expression in E. coli, and its antibacterial spectrum was determined. Molecular dynamics simulation and molecular biology experiments were conducted to explore the antibacterial target of AfRgly1. Results showed that the mRNA expression level of AfRgly1 was significantly upregulated after Vibrio alginolyticus infection. AfRgly1 has broad-spectrum antibacterial activity targeting on bacterial cell membrane, and it may also interact with bacterial DNA. AfRgly1 displayed low selectivity for fish red blood cells. These results indicate that AfRgly1 is an antimicrobial peptide with considerable potential for application in the development of therapeutic agents. Full article

The rise of multidrug-resistant pathogens has become a serious health concern, creating an urgent need for novel therapeutic approaches. Among the compounds explored, AMPs have emerged as promising candidates due to their broad-spectrum activity and low propensity for resistance development. However, their clinical implementation is limited by improper size, in vivo instability, and toxicity. Here, we designed short analogs of CeHS-1 via (1) truncation of intact CeHS-1, (2) amino acid substitution, (3) end-tagging, and (4) C-terminal amidation. The results showed that short analogs fused with an RWW stretch exhibited stronger antibacterial activity than the parent analogs, without inducing hemolysis in human red blood cells. Among the tested AMPs, mechanistic studies revealed membrane-disruptive activity of certain peptides against Staphylococcus aureus. In silico analyses also suggested that the analogs bind DNA by aligning parallel to its grooves, where the RWW stretch is believed to contribute to interactions between arginine and tryptophan residues and nitrogenous bases through electrostatic, hydrogen bonding, and hydrophobic interactions. The short CeHS-1 analogs established here may serve as potential alternative antimicrobial agents, which should be tested in clinical trials in the future. Full article

Staphylococcus species are often the cause of implant-related infections, posing a significant clinical challenge in orthopedics. Antimicrobial peptides (AMPs) like LL-37-derived FK-16 and GF-17 offer promising alternatives to conventional antibiotics; however, they require suitable delivery systems to overcome rapid degradation. The aim of this study was to develop and evaluate silk fibroin (SF) and osteoinductive peptide-enriched silk fibroin (PSF) sponges that can be used locally for FK-16 and GF-17 delivery. Two concentrations of FK-16 or GF-17 were loaded into SF and PSF sponges. Swelling behavior and AMP release profiles were analyzed for 72 h. Time-kill assays were conducted on MRSE and MRSA clinical strains to assess antimicrobial activity. FK-16 released quickly (>90% within 24 h) and then maintained a stable plateau from both SF and PSF matrices, which was associated with bactericidal activity against MRSE strains. In contrast, the release efficiency of GF-17 was lower and did not achieve significant antimicrobial effects. Neither peptide exhibited effective activity against MRSA under the tested conditions. PSF sponges showed higher swelling and enhanced FK-16-mediated antibacterial performance compared to SF counterparts. FK-16-loaded PSF sponges are a promising biomaterial for treating local orthopedic infections related to MRSE. The findings underscore the significance of peptide–matrix interactions in determining therapeutic outcomes and suggest the need for more in vivo evaluation of AMP-functionalized PSF scaffolds. Full article

Background/Objectives: Antimicrobial peptides (AMPs) have emerged as promising alternatives to conventional antibiotics in livestock, offering a sustainable strategy for controlling bacterial pathogens in food production systems. In addition to their direct antimicrobial effects, AMPs play a key role in modulating host-associated microbiomes, influencing both microbial composition and function. Advances in metagenomic sequencing and bioinformatic tools now enable comprehensive exploration of AMP diversity and activity within complex microbial ecosystems. Methods: In this study, we employed Illumina-based next-generation sequencing (NGS) to analyze intestinal contents from six gut sections of broiler chickens obtained from a Spanish slaughterhouse. Results: Through de novo assembly and bioinformatic annotation, we identified biosynthetic gene clusters (BGCs) encoding ribosomally synthesized and post-translationally modified peptides (RiPPs), other specialized bioactive secondary metabolites, antimicrobial resistance genes (ARGs), virulence factor genes (VFGs), and a diverse microbial community. Among all gut sections, the cecum exhibited the highest genetic richness, characterized by a high diversity of RiPP-like clusters and antimicrobial resistance determinants. Conclusions: These findings highlight the poultry gut, particularly the cecum, as a significant reservoir of antimicrobial peptides (AMPs) with potential implications in antibiotic-free poultry production and enhanced food safety. Full article

Antimicrobial peptides (AMPs) are increasingly emerging as alternatives to conventional antibiotics. This study compared the antibacterial activity of two decapeptides, KSL and KSL-W, and a 23-residue peptide, Dadapin-1, against bacterial species that colonize orthopedic implants, with the aim of identifying the most effective peptide for future AMP-based anti-infective orthopedic biomaterials. Staphylococcus aureus ATCC 25923 was the reference strain. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum biofilm inhibitory concentration (MBIC) of the AMPs were determined in both undiluted and diluted Mueller–Hinton Broth II (MHB II) to gain a simplified perspective on the potential interference of bioenvironments. The MBICs of the AMPs were close to their MICs. In diluted broth, a concentration of 3.91 μg/mL of KSL or KSL-W was bactericidal against staphylococci and prevented biofilm formation. An eight-fold higher concentration of Dadapin-1 was required to achieve bactericidal activity. Undiluted MHB II significantly hindered the antibacterial activity of KSL and Dadapin-1, while KSL-W was notably less affected. The values of LoA, a newly developed indicator of loss of activity, confirmed these findings. Bacterial species and strain influenced LoA. Furthermore, KSL-W exhibited a protective effect on osteoblasts co-cultured with S. aureus ATCC 25923. Overall, KSL-W emerged as the most promising candidate for AMP-based anti-infective orthopedic biomaterials. Full article

Background/Objectives: Burn wound infections present significant clinical challenges due to multidrug-resistant pathogens and the limitations of traditional antimicrobials. While antimicrobial peptides (AMPs) have broad-spectrum effectiveness, their instability in wound environments limits their use. This study compares properties of AMP-decorated nanostructured lipid carriers (NLCs) to free AMPs, focusing on their dermal penetration, retention, and antimicrobial efficacy in simulated ex vivo burn wound models. Methods: AMP-decorated NLCs (smart-AMPs) were produced by electrostatic and hydrophobic surface adsorption and characterized regarding their size, zeta potential, and physical short-term stability. The distribution of AMPs within the wounds was evaluated using an ex vivo porcine ear model with various wound types. The antimicrobial efficacy was assessed by monitoring the bioluminescence of Aliivibrio fischeri as a live bacterial marker for 24 h. Results: The size and zeta potential measurements confirmed the successful formation of smart-AMPs. The dermal penetration of AMPs was influenced by the type of wound and the type of AMP formulation (free AMPs vs. smart-AMPs). In the chronically infected burn wounds, which were characterized by the formation of a biofilm in a protein-rich wound fluid, the smart-AMPs resulted in a 1.5-fold higher and deeper penetration of the AMPs, and the antimicrobial activity was 6-fold higher compared to the free AMPs. Conclusions: smart-AMPs present an innovative approach for treating chronic, biofilm-associated wounds more efficiently than the current treatment options. Full article

Antimicrobial peptides (AMPs) are a primary defense against pathogens. Here, we examined the interaction of two BP100 analogs, R²R⁵-BP100 (where Arg substitutes Lys 2 and 5) and R²R⁵-BP100-A-NH-C₁₆ (where an Ala and a C₁₆ hydrocarbon chain are added to the R²R⁵-BP100 C-terminus), with membrane models. Large unilamellar vesicles (LUVs) and giant unilamellar vesicles (GUVs) were prepared with the major lipids in Gram-positive (GP) and Gram-negative (GN) bacteria, as well as red blood cells (RBCs). Fluorescence data, dynamic light scattering (DLS), and zeta potential measurements revealed that upon achieving electroneutrality through peptide binding, vesicle aggregation occurred. Circular dichroism (CD) spectra corroborated these observations, and upon vesicle binding, the peptides acquired α-helical conformation. The peptide concentration, producing a 50% release of carboxyfluorescein (C₅₀) from LUVs, was similar for GP-LUVs. With GN and RBC-LUVs, C₅₀ decreased in the following order: BP100 > R²R⁵-BP100 > R²R⁵BP100-A-NH-C₁₆. Optical microscopy of GP-, GN-, and RBC-GUVs revealed the rupture or bursting of the two former membranes, consistent with a carpet mechanism of action. Using GUVs, we confirmed RBC aggregation by BP100 and R²R⁵-BP100. We determined the minimal inhibitory concentrations (MICs) of peptides for a GN bacterium (Escherichia coli (E. coli)) and two GP bacteria (two strains of Staphylococcus aureus (S. aureus) and one strain of Bacillus subtilis (B. subtilis)). The MICs for S. aureus were strain-dependent. These results demonstrate that Lys/Arg replacement can improve the parent peptide’s antimicrobial activity while increasing hydrophobicity renders the peptide less effective and more hemolytic. Full article

The global rise in antimicrobial resistance poses a major threat to public health, with multidrug-resistant bacterial infections expected to surpass cancer in mortality by 2050. As traditional antibiotic pipelines stagnate, novel therapeutic alternatives are critically needed. Antimicrobial peptides (AMPs), particularly those derived from marine organisms, have emerged as promising antimicrobial candidates due to their broad-spectrum activity, structural diversity, and distinctive mechanisms of action. Unlike conventional antibiotics, AMPs can disrupt microbial membranes, inhibit biofilm formation, and even modulate immune responses, making them highly effective against resistant bacteria. This review highlights the potential of marine AMPs as next-generation therapeutics, emphasizing their efficacy against multidrug-resistant pathogens and biofilm-associated infections. Furthermore, marine AMPs show promise in combating persister cells and disrupting quorum sensing pathways, offering new strategies for tackling chronic infections. Despite their potential, challenges such as production scalability and limited clinical validation remain; nevertheless, the use of new technologies and bioinformatic tools is accelerating the discovery and optimization of these peptides, paving the way for bypassing these challenges. This review consolidates current findings on marine AMPs, advocating for their continued exploration as viable tools in the fight against antimicrobial resistance. Full article

Background/Objectives: Antimicrobial resistance (AMR) contributes to millions of deaths globally each year, creating an urgent need for new therapeutic agents. Antimicrobial peptides (AMPs) have emerged as promising candidates due to their potential to combat AMR pathogens. This study aimed to evaluate the antimicrobial activity of an AMP from a soil-derived bacterial isolate against Gram-negative bacteria. Method: Soil bacteria were isolated and screened for antimicrobial activity. The bioactive peptide was purified and determined its structure and antimicrobial efficacy. Genomic analysis was conducted to predict the biosynthetic gene clusters (BGCs) responsible for AMP production. Results: Genomic analysis identified the isolate as Paenibacillus sp. Na14, which exhibited low genomic similarity (61.0%) to other known Paenibacillus species, suggesting it may represent a novel species. The AMP from the Na14 strain exhibited heat stability up to 90 °C for 3 h and retained its activity across a broad pH range from 3 to 11. Structural analysis revealed that the Na14 peptide consisted of 14 amino acid residues, adopting an α-helical structure. This peptide exhibited bactericidal activity at concentrations of 2–4 µg/mL within 6–12 h, and its killing rate was concentration-dependent. The peptide was found to disrupt the bacterial membranes. The Na14 peptide shared 64.29% sequence similarity with brevibacillin 2V, an AMP from Brevibacillus sp., which also belongs to the Paenibacillaceae family. Genomic annotation identified BGCs associated with secondary metabolism, with a particular focus on non-ribosomal peptide synthetase (NRPS) gene clusters. Structural modeling of the predicted NRPS enzymes showed high similarity to known NRPS modules in Brevibacillus species. These genomic findings provide evidence supporting the similarity between the Na14 peptide and brevibacillin 2V. Conclusions: This study highlights the discovery of a novel AMP with potent activity against Gram-negative pathogens and provides new insight into conserved AMP biosynthetic enzymes within the Paenibacillaceae family. Full article

The white-spotted jellyfish, Phyllorhiza punctata, is an invasive species with significant ecological and economic relevance spreading across various regions. While its ecological impact is well-documented, its molecular and biochemical characteristics remain poorly understood. In this study, we integrate proteomic data generated by LC-MS/MS with publicly available transcriptomic information to characterize P. punctata, analyzing differential protein expression across three distinct tissues: oral arms, mantle, and gonads. A total of 2764 proteins and 25,045 peptides were identified, including several venom components such as jellyfish toxins (JFTs) and phospholipase A2 (PLA2), which were further investigated and compared to toxins from other species. Enrichment analyses revealed clear tissue-specific functions. Additionally, deep learning and machine learning tools identified 274 promising AMP candidates, including the α-helical, β-sheet, and αβ-motif peptides. This dataset provides new insights into the protein composition of P. punctata and highlights strong AMP candidates for further characterization, underscoring the biotechnological potential of underexplored cnidarian species. Full article

Background/Objectives: The clinical potential of antimicrobial peptides (AMPs) against dual threats like antimicrobial resistance (AMR) and cancer is often limited by their high host cell toxicity. Here, we focused on brevinin-2OS (B2OS), a novel peptide from the skin of Odorrana schmackeri with potent haemolytic activity. The objective was to study the structure–activity relationship and optimise the safety via targeted modifications. Methods: A dual-modification strategy involving C-terminal truncation and subsequent N-terminal D-amino acid substitution was employed. The bioactivities and safety profiles of the resulting analogues were evaluated using antimicrobial, haemolysis, and cytotoxicity assays. Result: Removal of the rana box in B2OS(1-22)-NH₂ substantially reduced haemolysis while maintaining bioactivities. Remarkably, the D-leucine substitution in [D-Leu²]B2OS(1-22)-NH₂ displayed a superior HC₅₀ value of 118.1 µM, representing a more than ten-fold improvement compared to its parent peptide (HC₅₀ of 10.44 µM). This optimised analogue also demonstrated faster bactericidal kinetics and enhanced membrane permeabilisation, leading to a greater than 22-fold improvement in its therapeutic index against Gram-positive bacteria. Conclusions: The C-terminal rana box is a primary determinant of toxicity rather than a requirement for activity in the B2OS scaffold. The engineered peptide [D-Leu²]B2OS(1-22)-NH₂ emerges as a promising lead compound, and this dual-modification strategy provides a powerful design principle for developing safer, more effective peptide-based therapeutics. Full article

Antimicrobial peptides (AMPs) provide a robust alternative to conventional antibiotics, combating escalating microbial resistance through their diverse functions and broad pathogen-targeting abilities. While current deep learning technologies enhance AMP generation, they face challenges in developing multifunctional AMPs due to intricate amino acid interdependencies and limited consideration of diverse functional activities. To overcome this challenge, we introduce a novel de novo multifunctional AMP design framework that enhances a Feedback Generative Adversarial Network (FBGAN) by integrating a global quantitative AMP activity regression module and a multifunctional-attribute integrated prediction module. This integrated approach not only facilitates the automated generation of potential AMP candidates, but also optimizes the network’s ability to assess their multifunctionality. Initially, by integrating an effective pre-trained regression and classification model with feedback-loop mechanisms, our model can not only identify potential valid AMP candidates, but also optimizes computational predictions of Minimum Inhibitory Concentration (MIC) values. Subsequently, we employ a combinatorial predictor to simultaneously identify and predict five multifunctional AMP bioactivities, enabling the generation of multifunctional AMPs. The experimental results demonstrate the efficiency of generating AMPs with multiple enhanced antimicrobial properties, indicating that our work can provide a valuable reference for combating multi-drug-resistant infections. Full article

The emergence of multidrug-resistant pathogens has driven the development of novel antimicrobial peptides (AMPs) as therapeutic alternatives. Lactolisterin LBU (LBU) is a bacteriocin with promising activity against Gram-positive bacteria, including Staphylococcus aureus. In this study, we designed and evaluated a panel of amino acid variants of LBU to investigate domain–activity relationships and improve activity. Peptides were commercially synthesized, and their effect was evaluated for minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), hemolytic activity, cytotoxicity, in vivo toxicity, and virulence modulation. AlphaFold3 structural prediction of LBU revealed a four-helix topology with amphipathic and hydrophobic segments. Helical wheel projections identified helices I and IV as amphipathic, suggesting their potential involvement in membrane interaction and activity. Glycine-to-alanine substitutions at helix I markedly increased antimicrobial activity but altered toxicity profiles. In contrast, changes at helix junctions and kinks reduced antimicrobial activity. We also showed differential regulation of virulence genes upon sub-MIC treatment. Overall, rational substitution enabled identification of residues critical for activity and toxicity, providing insights into therapeutic tuning of lactolisterin-based peptides. Full article

Background/Objectives: Lactiplantibacillus plantarum is widely utilized in the fermentation industry and offers potential health benefits. However, large-scale comparative genomic analyses aimed at exploring its metabolic functions and conducting safety assessments are still lacking. Methods: In this study, we performed a comparative genomic analysis of 324 L. plantarum strains sourced from various origins and geographical locations. Results: The results revealed that L. plantarum possesses a total of 2403 core genes, of which 12.3% have an unknown function. The phylogenetic analysis revealed a mixed distribution from various origins, suggesting complex transmission pathways. The metabolic analysis demonstrated that L. plantarum strains can produce several beneficial metabolites, including lysine, acetate, and riboflavin. Furthermore, L. plantarum is highly capable of degrading various carbohydrates and proteins, increasing its adaptability. Further, we profiled the antimicrobial peptides (AMPs) in the genomes of L. plantarum. We identified a widely distributed AMP and its variants, presenting in a total of 280 genomes. In our biosafety assessment of L. plantarum, we identified several antibiotic resistance genes, such as Tet(M), ANT(6)-Ia, and mdeA, which may have potential for horizontal gene transfer within the Lactobacillaceae family. Conclusions: This study provides genomic insights into the genetic diversity, metabolic functions, antimicrobial properties, and biosafety of L. plantarum, underscoring its potential applications in biotechnology and environmental adaptation. Full article

Background: People with cystic fibrosis (pwCF) frequently suffer from chronic lung infections, with Pseudomonas aeruginosa being the predominant pathogen contributing to disease progression and morbidity. The increasing prevalence of multi-drug-resistant (MDR) P. aeruginosa has diminished treatment options. Antimicrobial peptides (AMPs) have emerged as promising alternatives to conventional antibiotics due to their unique membrane-targeting mechanisms. OMN51, a novel bioengineered AMP derived from capitellacin, was evaluated for antimicrobial activity against P. aeruginosa in sputum samples from pwCF. This study aimed to compare the bactericidal effects of OMN51 with those of a range of conventional antibiotics known to have activity against P. aeruginosa clinical isolates derived from pwCF. Methods:P. aeruginosa clinical isolates were obtained from fifty-six unique sputum cultures of pwCF at a tertiary-university-affiliated hospital. Minimum inhibitory concentrations (MICs) of OMN51 and comparator antibiotics were determined using broth microdilution. Antimicrobial susceptibility was evaluated using the Kirby–Bauer disc diffusion method. Results: OMN51 demonstrated in vitro bactericidal activity across all P. aeruginosa isolates, including MDR strains. MIC values for OMN51 ranged from 4 to 16 µg/mL, with no observed resistance or cross-resistance. Comparative analysis revealed the superior efficacy of OMN51 compared with conventional antibiotics. Conclusions: OMN51 exhibits robust in vitro activity against MDR P. aeruginosa, supporting its candidacy as a therapeutic agent for MDR P. aeruginosa- associated infections. Further studies are warranted to assess pharmacokinetics and in vivo safety and efficacy. OMN51 represents a first-in-class, membrane-targeting therapeutic showing promise against MDR P. aeruginosa. Full article