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Bacterial Genetics

Our group has been studying for more than 30 years the mechanisms of antibiotic resistance in Streptococcus pneumoniae (Spn). Our objectives are to understand the molecular basis of antimicrobial action, to search for new targets of action and new compounds. Seconeolitsine (SCN) is one of these new compounds targeting topoisomerase I (Topo I). As for the search for new targets, our research has focused in recent years on the factors that organize the topology of the chromosome, allowing optimal compaction (about 1000-fold) to harmonize its replication, chromosome segregation and gene expression. This compaction is mediated both by the level of DNA supercoiling (Sc) and by association with nucleoid-binding proteins (NAPs). The level of Sc depends mainly on the enzymatic activities of their DNA topoisomerases, reaching a homeostatic equilibrium by the opposite activities of the topoisomerases that relax DNA (Topo I and Topo IV), and of gyrase, which introduces negative Sc. Our group has characterized the three Spn topoisomerases and two NAPs: HU and SatR. In addition, the availability of antimicrobials that inhibit each of the Spn topoisomerases has allowed us to analyze their transcriptome under conditions of local or global change of the Sc level and to define gene domains of coordinated transcription and similar functions. Fluoroquinolones, which inhibit Topo IV and gyrase, produce local changes in Sc that induce alterations in 6% of the transcriptome, altering metabolic pathways that originate an increase in reactive oxygen species (ROS) that contribute to lethality, in accordance with the general mechanism of bactericidal antibiotics. On the other hand, the induction of global changes in Sc by novobiocin (NOV, gyrase inhibitor), or by SCN (Topo I inhibitor), has allowed us to define topological domains. Global changes in Sc include the regulation of topoisomerase genes: its decrease activates the transcription of gyrase genes (gyrA, gyrB) and inhibits those of Topo IV (parEC) and Topo I (topA); the increase in Sc regulates the expression of topA. Decreased Sc affects 37% of the genome, with >68% of genes clustered in 15 domains. Increased Sc affects 10% of the genome, with 25% of the genes clustered in 12 domains. The AT content in the genome correlates with the domains, being higher in UP domains than in DOWN domains. The genes in the different domains have common functional characteristics, indicating that they have been subjected to topological selective pressure to determine the location of genes involved in metabolism, virulence and competition. 

The current objectives of the group are:
1.    Identification of factors that stabilize chromosome topology: NAPs, ncRNAs, intra-chromosomal interactions.
2.    Regulation of transcription in response to topological stress: in vivo localization of DNA topoisomerases, RNA polymerase and NAPs.
3.    Topo I as a new antimicrobial target and action of SCN. 
4.    Design of antisense RNAs and use of the CRISPR system as new antibacterial agents.

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Viral load, CMV-specific T-cell immune response and cytomegalovirus disease in solid organ transplant recipients at higher risk for cytomegalovirus infection during preemptive therapy.

Martín-Gandul C, Pérez-Romero P*, Blanco-Lobo P, Benmarzouk-Hidalgo OJ, Sánchez M, Gentil MA, Bernal C, Sobrino JM, Rodríguez-Hernández MJ, Cordero E; Spanish Network for Research in Infectious Diseases (REIPI). Viral load, CMV-specific T-cell immune response and cytomegalovirus disease in solid organ transplant recipients at higher risk for cytomegalovirus infection during preemptive therapy. Transpl Int. 2014 Oct;27(10):1060-8.

PUBMED DOI

What is responsible for a large and unusual outbreak of leishmaniasis in Madrid?

8. Carrillo E, Moreno J, Cruz I. What is responsible for a large and unusual outbreak of leishmaniasis in Madrid? Trends Parasitol. 2013 Dec;29(12):579-80.

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HCV eradication with IFN-based therapy does not completely restore gene expression in PBMCs from HIV/HCV-coinfected patients.

9. Brochado O, Martínez I (*), Berenguer J, Medrano L, González-García J, Jiménez-Sousa MA, Carrero A, Hontañón V, Navarro J, Guardiola JM, Pérez-Latorre L, Micán R, Fernández-Rodríguez A (‡), Resino S (* ‡). HCV eradication with IFN-based therapy does not completely restore gene expression in PBMCs from HIV/HCV-coinfected patients. J Biomed Sci 2021; 28:23 (A; FI= 12.77; D1, Medicine, Research & Experimental; JCR 2021).

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Dynamics of HIV Reservoir and HIV-1 Viral Splicing in HCV-Exposed Individuals after Elimination with DAAs or Spontaneous Clearance.

Martínez-Román P, Crespo-Bermejo C, Valle-Millares D, Lara-Aguilar V, Arca-Lafuente S, Martín-Carbonero, Ryan P, De los Santos I, López-Huertas MR, Palladino C, Muñoz-Muñoz M, Fernández-Rodríguez A*, Coiras M, Briz V, on behalf of COVIHEP network. Dynamics of HIV Reservoir and HIV-1 Viral Splicing in HCV-Exposed Individuals after Elimination with DAAs or Spontaneous Clearance. Journal of Clinical Medicine 2022, 11: 3579.

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List of staff

Información adicional

El Laboratorio de Referencia e Investigación en Micología del Centro Nacional de Microbiología del Instituto de Salud Carlos III es el laboratorio de referencia de Micología para toda España. Además, mantiene varias líneas de investigación, entre las que destacan: Identificación de levaduras y hongos filamentosos, estudio de los mecanismos de resistencia de los hongos a los antifúngicos, estandarización de las pruebas de sensibilidad a los antifúngicos de los hongos patógenos, correlación in vivo-in vitro con modelos experimentales y pacientes, epidemiología molecular de la infección fúngica nosocomial, determinación de niveles de antifúngicos y diagnóstico rápido de las micosis invasoras mediante técnicas de diagnóstico rápido como PCR en Tiempo Real. El grupo de Investigadores constituye un equipo multidisciplinar con capacidad de formar y producir conocimiento científico de calidad, en el área de micología médica. Durante los últimos años se han leído 5 tesis doctorales en el departamento y actualmente el laboratorio cuenta con tres becarios pre-doctorales y dos postdoctorales. Además, cada año acogemos 3-5 estudiantes que desarrollan sus proyectos fin de Master o Grado y rotantes de la especialidad de Microbiología Clínica de distinta procedencia Nacional. Todos ellos participan en un programa de formación que comprende sesiones bibliográficas, teóricas y reuniones científicas que les permiten adquirir una formación global de la micología.

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