Mar Cendra
IBEC, Microbial biotechnology and host-pathogen interaction
Riccardo Levato
IBEC, Biomaterials for Regenerative Therapies

"Ribonucleotide reductases: a paradigm of redundant enzymes in bacteria"

Ribonucleotide reductases (RNR) are essential enzymes in all-living organisms because it catalyses the reduction of the four different ribonucleotides (NTPs) to its corresponding deoxyribonucleotides (dNTPs) necessaries for the DNA synthesis and repair. Three different RNR classes (I, II and III) can be distinguished based on structural differences, metallo-cofactor requirements, mechanisms for radical generation, and responses to oxygen. Escherichia coli encodes for three types of RNR: two RNR classes are active only under aerobic conditions (Class Ia and Ib) and class III only active under anaerobic conditions The different RNR classes in E. coli has been extensively studied from the biochemical, biophysical and structural point of view but the transcriptional regulation of its genes are not known. In addition to we need to establish the role of each RNR during infection and biofilm formation. The aim of our work is to study the transcriptional regulation of the different RNR in E. coli and especially how the different RNR are co-ordinately express and their role in each step of the biofilm formation, which is important in the establishment of chronic infection in some pathogenic E. coli strains.

Moreover we have investigated the implication of the H-NS (nucleoid-associate protein) transcriptional factor to be one of the first repressor identified for the transcriptional regulation of some RNR genes in E. coli.

Mar Cendra
IBEC, Microbial biotechnology and host-pathogen interaction

 

"Biodegradable Microcarriers for Cell and Drug Delivery"

Biodegradable microcarriers (particles and spheres) constitute versatile systems for advanced therapies and regenerative medicine. Microcarriers can be loaded with bioactive molecules and delivered topically at a injury site through minimally invasive injections and also, as they display very high surface area, are suitable for expansion and 3D culture of anchorage-dependent cells. Cells-microcarries constructs are also less likely to be dispersed by biological fluids when compared to cells alone. These features are of great interest in Tissue Engineering, where microcarriers can be used as discrete scaffolds or building blocks for geometrically complex scaffolds.

In this work, biocompatible and biodegradable microcarriers are fabricated using polylactic acid (PLA) and a novel fabrication method using only non-toxic chemicals was explored. Parameters important in microparticulate scaffold design, including porosity and surface properties of the carriers were studied and improved cell responses in terms of adhesion and proliferation of mesenchymal stem cells are achieved by modifying microcarriers surface chemistry by means of extracellular matrix protein covalent grafting. The PLA microcarriers preparation, properties and cell homing ability will be discussed.

Riccardo Levato
IBEC, Biomaterials for Regenerative Therapies



When: Friday 24 February 2012, 10:00
Where: IBEC, floor 11, Tower I
Baldiri Reixac 4-8, 08028 Barcelona