Group Leader/s



This group studies several aspects of the biology of Gram-positive bacteria which impact on human health, such as their interaction with eukaryotic cells, their plasmids and their metabolites.

Gram-positive bacteria include pathogenic organisms, such as species belonging to the Streptococcus genus but also others strains that are beneficial to human health. Among the latter are lactic acid bacteria (LAB), some of which are considered to be probiotic. Likewise, there are a number of metabolites produced by these organisms, such as vitamins as well as certain polysaccharides (prebiotics) whose functions, among others, is to enhance the development of a microbiota that is beneficial to the human gastrointestinal tract, as well as possibly possessing an immunomodulating effect. These aspects constitute an important field of research that could lead to the production of fermented functional foods (and beverages) which benefit human health. In addition, our research also involves the study of plasmids present in the Gram-positive bacterial genomes, which have a beneficial effect, due to their encoding metabolic pathways, whose products are of nutritional value. However, the presence of these plasmids could also have a detrimental effect, when they encode determinants for antibiotic resistance and are present in pathogenic bacteria i.e. Streptococcus pneumoniae or Staphylococcus aureus.

Bearing in mind the above, our work group is pursuing the following lines of research: 1) a study of the probiotic potential of Lactobacillus and Pediococcus strains that produce homopolysaccharides, and a physiochemical and biochemical/biological evaluation of the produced polysaccharides. 2) Study of both the replication and the regulation of gene expression at the molecular, biochemical and structural levels, using plasmids of Gram-positive bacteria as model systems. 3) Studies of the role of  toxin-antitoxin systems on plasmid maintenance and bacteria persistence during infection using Gram-negative bacteria as a model. 4) Development of plasmid vectors for gene expression and the characterisation of their suitability for fluorescent labelling in Gram-positive bacteria. 5) Interactomic studies of bacteria with eucaryotic cells.


Pérez-Ramos A, Werning ML, Prieto A, Russo P, Spano G. Mohedano ML, López P  [2017]. Characterization of the sorbitol utilization cluster of the probiotic Pediococcus parvulus 2.6: genetic, functional and complementation studies in heterologous hosts. Front. Microbiol., 8: 2393.

Zarour K, Llamas Mª Goretti, Prieto A, Rúas-Madiedo P, Dueñas MT, Fernández de Palencia P., Aznar R, Kihal M, López, P.  [2017]. Rheology and bioactivity of high molecular weight dextrans synthesised by lactic acid bacteria. Carbohy. Polym. 174: 646–657. 0144-8617

Pérez-Ramos A, Nacher-Vazquez M, Notararigo S, López P, Mohedano ML  [2015]. Current and future applications of bacterial extracellular polysaccharides. In: Probiotics, Prebiotics, and Synbiotics: Chapter 22. Eds Victor R Preedy and Ronald Ross Watson. Elsevier Oxford, UK. ISBN: 9780128021897

López-Aguilar C, Romero-López C, Espinosa M, Berzal-Herranz A, del Solar G  [2015]. The 5′-tail of antisense RNAII of pMV158 plays a critical role in binding to the target mRNA and in translation inhibition of repB. Front. Genet. 6:225. doi: 10.3389/fgene.2015.00225.

Ruiz-Masó JA, Machón C, Bordanaba-Ruiseco L, Espinosa M, Coll M del Solar G  [2015]. Plasmid rolling circle replication. Microbiol Spectrum 3 (1). doi:10.1128/microbiolspec.PLAS-0035-2014

Werning ML, Pérez-Ramos A, Fernández de Palencia P, Mohedano ML, Dueñas MT, Prieto A, López P  [2014]. A specific immunological method to detect and quantify bacterial 2-substituted (1,3)-β-D-glucan. Carbohy Polym 113: 39–45. DOI: 10.1016/j.carbpol.2014.06.07

Notararigo S, de las Casas-Engel M, Fernández de Palencia P, Corbí AL, López P  [2014]. Immunomodulation of human macrophages and myeloid cells by 2-substituted (1-3)-β-D-glucan from P. parvulus 2.6. Carbohy Polym 112:109–113. Doi: 10.1016/j.carbpol.2014.05



2006-2010. Project AGL2006-11932-C05. Spanish Ministery of Education and Science. Prebiotics and probiotics for elaboration of functional food. Characterisation and evaluation of exopolysaccharides and their producer bacteria. Coordinator: Paloma López.

2006-2010. Project S-BIO-0260. Madrid Autonomy. COMBACT. Coordinator: Miguel Vicente.

2007-2010. Project BFU2007-63575/BMC. Spanish Ministery of Education and Science. Biochemical and structural studies of the pathogenic bacteria Streptococcus pneumoniae and its plasmids. Responsible scientific: Gloria del Solar.

2008-2010. VII Framework Program Project KBBE-CT-2007-211441. European Union (EU). Controlling biogenic amines in traditional food fermentations in regional europe. Responsible scientific at the CIB: Paloma López.

2009-2013. VII Framework Program Project FP7-PEOPLE-ITN-2008-238490. UE: Scientific Training in Antimicrobial Research Strategies. EU: Responsible scientific at the CIB: Paloma López.

2009-2015. Subprogram CONSOLIDER-INGENIO 2010 Project CSD00C-08-41920. Spanish Ministery of Science and Innovation. Coordinator: Manuel Espinosa.

2010-2014. Project AGL2009-12998-C03. Spanish Ministery of Science and Innovation. Glucan producing Lactobacilli and Pediococci strains. Evaluation of their probiotic characteristics and analysis of the physico-chemical and functional properties of their exopolysaccharides. Coordinator: Paloma López.

2011-2015. Project BFU2010-19597/BMC. Spanish Ministery of Science and Innovation. Streptococcus pneumoniae and its promiscuous plasmid pMV158: monologs, dialogs and intercomunications. Responsible scientific: Gloria del Solar.

2012-2014. Project BFU2011-14145-E. Spanish Ministery of Science and Innovation. Spanish network of plasmids and another movil elements (REDEEX-2). Coordinator: Gloria del Solar.

2013-2016. Project AGL2012-40084-C03. Ministery of Economy and Competitiveness. Identification of immunomodulating prebiotic polysaccharides and probiotic bacteria for use in novel functional food. Coordinator: Paloma López.

2015-2017. Project AGL2015-71923-REDT. Ministery of Economy and Competitiveness. Lactic acid bacteria and their relationship with health, quality and security of food (RedBAL). Responsible scientific at CIB: Paloma López. Coordinator: Patricia Ruas.

2015-2017. Project BIO2015-69085-REDC. Interactions between plasmidic modules and bacterial chromosomes: a due visit. Ministery of Economy and Competitiveness. Gloria del Solar: member of the research team. Coordinator: Antonio Juárez.

2016-2018. Project AGL2015-65010-C3-1-R. Ministery of Economy and Competitiveness. Development and evaluation of functional food based in bacterial homopolysaccharides.Responsible scientific: Paloma López.

2017-2019. Projects CYTED 917PTE0537 and PCIN-2017-075. Iberoamerican program for  development of science and technology and Ministery of Economy, Industry and Competitiveness. Vegetal food with probiotic functionality for undernourised infant population. Responsible scientific at CIB: Paloma López. Coordinator: Patricia Ruas.


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