Project Details
Projekt
Isolation and physiological characterization of cell types from heterogeneous aggregates of Staphylococcus aureus using transcriptomic analysis
Applicant
Dr. Daniel López
Subject Area
Metabolism, Biochemistry and Genetics of Microorganisms
Term
from 2012 to 2018
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 217573181
During the first period of this SPP1617 program, we showed that multicellular aggregates of the bacterial pathogen Staphylococcus aureus are constituted by a heterogeneous population of, at least, two different cell types, biofilm producers and toxin producers. We used a number of biochemical techniques to characterize the molecular mechanism that drives to this cell differentiation. We found a complex genetic regulation triggered by the bimodal behavior of the quorum-sensing cascade agr, which ultimately selects for the progression of acute (higher concentration of toxin producers) or biofilm-associated chronic infections (higher concentration of biofilm producers). In this renewal, we will physiologically characterize these two distinct subpopulations that we find in S. aureus biofilms. To do this, we have setup a new cell-sorting methodology that permits the isolation of each one of these subpopulations to further analyze their transcriptomic profile after isolation. This approach will allow us determining the physiological characteristics of each cell type to better understand their specialization within the biofilm. Moreover, to test the versatility of our approach, we will provide this sorting + RNA-seq technology to any laboratory of this consortium that is interested in characterizing a subpopulation of cells. Furthermore, we will combine our cell sorting + RNA-seq technology with our state-of-the-art microscopic techniques to perform a spatio-temporal localization of the subpopulations within the S. aureus aggregates. The combination of these two approaches will provide a better understanding of the role of specialized cell types within microbial communities and whether this is connected to the specific physiological state of each cell type. The third goal of this proposal will study the differential sensitivity of the subpopulations, biofilm producers and toxin producers, to antimicrobial treatments that are conventionally used to eliminate S. aureus biofilms. Cell types with different transcriptomic profiles and different physiologies may display different sensitivities to antibiotics and may develop into difficult-to-treat staphylococcal infections. We will study the capacity of each cell type to resist an antibiotic treatment based on their physiological profile. Overall, our project will demonstrate that S. aureus communities are constituted by cell types that are physiologically different and will demonstrate that the general physiology of each cell type is related to their role within the biofilm and their capacity to resist antimicrobial treatments. Our approach should be of interest to other research groups of this consortium.
DFG Programme
Priority Programmes
