Cellular Biotechnology

Microbial biotechnology and host-pathogen interaction

Prof. Dr. Juárez, Antonio
Group Leader

Ed. Hèlix | Baldiri Reixac 15-21 | 08028 | Barcelona
Email : ajuarezibecbarcelona.eu

Research Topics

Pathogenic bacteria / Nucleoid-associated proteins / Ribonucleotide Reductases / Bacterial biofilms / Single cell studies / Atomic Force Microscopy

1. Structure and function of bacterial proteins that modulate virulence expression

Protein–protein and protein–DNA interactions play key roles in the ability of virulent bacteria to adapt to the host environment and cause disease. A group of proteins is currently the focus of our research: nucleoid-associated proteins (NAPs) that contribute to DNA architecture and modulate gene expression. We are interested in unravelling the role played by two of these proteins – Hha and H-NS – in the regulation of virulence and of plasmid transfer. Escherichia coli pathotypes such as enteroaggregative E. coli are the subject of our research. Owing to their key modulatory functions, these proteins are interesting targets to combat bacterial infections.

Trapping of Escherichia coli cells in a dielectrophoresis chip

2. Bacterial plasmids and their role in transmission of multidrug resistance markers

A main concern with bacterial infections is the selection of isolates that are resistant to several antimicrobial drugs. The transmission of the ability of bacterial cells of simultaneously resist to several antimicrobial drugs is accomplished in many instances by plasmids. These genetic elements can be transmitted from one cell to another, and modify the phenotype of the recipient cell. We are trying to understand the molecular mechanisms whereby Salmonella incorporates IncHI1 plasmids and becomes multiresistant to several antibiotics.

Hha perturbing H-NS structure

3. Application of nanotools of bacterial biotechnology

3.1. Dielectrophoresis. We have previously shown that dielectrophoresis can be a valuable tool for bacterial cell sorting and characterization. We are currently using different chip designs (2D and 3D carbon electrodes) to: a) study the effect of electric fields on bacterial cell physiology; b) combine DEP with other molecular protocols for detection and identification of diffent types of cells.

3.2. Atomic force microscopy (AFM). Conventional AFM approaches have been shown to be powerful techniques for characterizing both biomaterials and biomolecules. In a joint project with the Nanoscale Bioelectrical Characterization group, we intend to use electrical-AFM to characterize the bacterial cell envelope. We also plan to use this approach to analyze the structural and physiological properties of bacterial living cells.