Enterocin A

Objectives: Bacterial resistance to most common antibiotics is a harbinger of the requirement to find novel anti-infective, antimicrobials agents, and increase innovative strategies to struggle them. Numerous bacteria produce small peptides with antimicrobial activities called bacteriocin. This study aimed to investigate the antibacterial properties of the fusion protein of Enterocin A and Colicin E1 modified against pathogens. Materials and methods: Analysis of recombinant bacteriocin Enterocin A and Colicin E1 (ent A-col E1) was performed to assay the stability and antibacterial activity of this fusion protein. The pET-22b vector was employed to express the coding sequence of the ent A-col E1 peptide in Escherichia coli BL21 (DE3). Minimum inhibitory concentration (MIC), disk diffusion, and time-kill tests were performed to evaluate the antibacterial activity of the ent A-col E1 against Pseudomonas aeruginosa (ATCC 9027), Escherichia coli (ATCC 10536), Enterococcus faecalis (ATCC 29212), and Staphylococcus aureus (ATCC 33591). Results: The suggested recombinant peptide had good antibacterial activity against both Gram-negative and Gram-positive pathogens. It has also good stability at various temperatures, pH levels, and salt concentrations. Conclusion: Because bacteriocins are harmless compounds, they can be recommended as therapeutic or preventive supplements to control pathogens. According to the obtained results, the ent A-col E1 peptide can serve as an efficient antibacterial compound to treat or prevent bacterial infections.

Cancer is one of the most causes of death all over the world, although improvements in its treatment and recognition. Due to the limitations of common anticancer methods, including surgery, chemotherapy, and radiotherapy, attention has been drawn to other anti-cancer compounds, especially natural peptides such as bacteriocins. In this study, we used a combination of two bacteriocins, colicin E1 and enterocin A, against AGS gastric cancer cell lines. In order to evaluate anticancer properties of fusion peptide, we applied MTT assay, real-time PCR, and flow cytometry tests. This is the first report to show the cell growth inhibitory activity of the enterocin A in combination with colicin E1 against AGS human cancer cells. The results of this study showed that this fusion peptide at a concentration of 60.4 µg/mL and 24 h was able to kill half of the tested cancer cells, and treatment of the cells with this concentration increased the expression of bax and caspase 3 genes and reduced the expression of bacl-2 in 24 h. Flow cytometry analysis of annexin V-FITC/propidium iodide results also showed that our peptide was able to induce apoptosis in treated cells compared with control. Taken together, enterocin A-colicin E1 (ent A-col E1) can be considered as a good candidate for anticancer therapies.

To minimize the survival of Listeria monocytogenes on ready-to-eat (RTE)-products, active antimicrobial packaging based on polyvinyl alcohol films with Enterocin A or ethyl-lauroyl-arginate (LAE) have been designed and its antimicrobial activity assessed in vacuum-packed sliced dry-cured ham stored under refrigeration. The Enterocin A-based antimicrobial film exerted a strong antilisterial activity, causing an immediate reduction of L. monocytogenes counts of 1 log units compared with the control without antimicrobial. Besides, Enterocin A film enhanced (4-fold higher) the die-off rate along the 6 months of storage at 8 °C. The antilisterial effect of Enterocin A film applied on dry-cured ham complies with the performance criteria requirement of Alternative 1 of the US Listeria rule regarding the control of L. monocytogenes. Films made with LAE did not exert an immediate bactericidal effect but slightly increased the die-off rate of the pathogen and reduced its counts during the shelf life compared to the control batch.