Pediocin heterologous expression and its effects over Listeria spp. and human gut microbial population

• Grant number: 18/02519-7
• Support type: Scholarships abroad - Research Internship - Post-doctor
• Effective date (Start): April 29, 2018
• Effective date (End): April 28, 2019
• Field of knowledge: Biological Sciences - Microbiology
• Principal Investigator: Ricardo Pinheiro de Souza Oliveira
• Grantee: Taís Mayumi Kuniyoshi
• Supervisor abroad: Paul Cotter
• Home Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Local de pesquisa : Moorepark Food Research Centre, Ireland
• Associated to the scholarship: 15/24777-0 - Optimization of pediocin a production in Pediococcus pentosaceus ATCC 43200, BP.PD

Abstract

The search for new antimicrobial composites as an alternative to the use of antibiotics is one the greatest modern challenges from the pharmacy and food industry due to the high frequency of super-resistant bacterial lineages. In this scenario, antimicrobial peptides, known as bacteriocins, have been standing out and are already being used in a variety of biotechnological processes. Gastrointestinal bacterial infection treatments using bacteriocins may be interesting since some of these biomolecules possess a narrow antimicrobial activity and can avoid commensal gut microbiota unbalance and even antibiotic-associated diarrhea. Pediocin is a bacteriocin that belongs to class IIa, known for its effective antimicrobial activity against pathogenic bacterium Listeria monocytogenes. This bacteriocin is not yet licensed for human use, even though there is a great number of concluded studies on biomedical and food areas. The cost of the commercial pediocin is still quite large, and its purification from its natural producer demands a lot of steps in addition to its low yield, which hinder its study in the medical area. Thus, in the first step of this project we intend on producing heterologously two pediocin isoforms: pediocin PA-1 and penocin A, both fused to a histidin tail and to the maltose binding protein (MBP), for posterior affinity purification of them. Another objective is to verify the effect of both purified pediocins (~95%) against Listeria spp. and human gut microbial diversity in a simulated human distal colon model using Listeria selective medium, qPCR (total bacterial number) and metagenomic sequencing (Illumina MiSeq platforms) for analysis. The relevance of this project is reinforced as it is going to be the first time that the effect of both pediocin variants will be evaluated in a similar environment to the human distal colon. Besides, the use of last generation techniques in molecular biology area will enable a more precise and refined analysis over the small fluctuations in the gut microbiota. (AU)