Analysis of the contribution of a new antibacterial T6SS effector of Salmonella enterica serovar Oslo in bacterial competitions

• Grant number: 22/01444-9
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): April 01, 2022
• Effective date (End): February 28, 2023
• Field of knowledge: Biological Sciences - Microbiology - Biology and Physiology of Microorganisms
• Principal researcher: Ethel Bayer Santos
• Grantee: Lior Karman
• Home Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 17/02178-2 - Function of type VI secretion systems of pathogenic bacteria in the interaction with eukaryotic cells, AP.JP

Abstract

The type 6 secretion system (T6SS) is an antibacterial weapon that injects toxic effectors into either eukaryotic or prokaryotic cells via cell-to-cell contact. The T6SS effectors have a wide range of biochemical activities and confer a competitive advantage to the bacteria that produce them, causing growth inhibition and/or death of target cells. Salmonella enterica is one of the species that uses this antibacterial apparatus to compete with endogenous species of the intestinal microbiota, which allows the colonization of the host. To date, only two antibacterial effectors secreted by the T6SS from S. enterica have been described. Using bioinformatics approaches to analyze 10k S. enterica genomes, our group identified a putative effector encoded by Salmonella enterica serovar Oslo, whose domain organization is characteristic of an evolved T6SS effector. Preliminary results revealed that the putative effector is toxic when expressed in Escherichia coli, and that the gene encoded downstream neutralizes the toxic effect, indicating that it is the cognate immunity protein. The aim of this project is to determine if the putative effector is secreted by T6SS from S. Oslo during bacterial competitions. In addition, we intend to clone the effectors and their cognate immunity protein for future biochemical and structural assays. This project contributes to the characterization of new antimicrobials that may help in the development of new strategies to combat bacterial resistance. (AU)