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Mycobacteria

Líneas de investigación

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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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Publicaciones destacadas

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Guiding the humoral response against HIV-1 toward a MPER adjacent region by immunization with a VLP-formulated antibody-selected envelope variant

Beltran-Pavez C, Ferreira CB, Merino-Mansilla A, Fabra-Garcia A, Casadella M, Noguera-Julian M, Paredes R, Olvera A, Haro I, Brander C, Garcia F, Gatell JM, Yuste E, Sanchez-Merino V; PLoS One. 2018 Dec 19;13(12):e0208345

PUBMED DOI

The role of methionine synthases in fungal metabolism and virulence

Scott J and Amich J. Essays Biochem (2023) 67 (5): 853-863.

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Global Meningococcal Initiative: Insights on antibiotic resistance, control strategies and advocacy efforts in Western Europe

Borrow R, Campbell H, Caugant DA, Cherkaoui A, Claus H, Deghmane AE, Dinleyici EC, Harrison LH, Hausdorff WP, Bajanca-Lavado P, Levy C, Mattheus W, Mikula-Pratschke C, Mölling P, Sáfadi MA, Smith V, van Sorge NM, Stefanelli P, Taha MK, Toropainen M, Tzanakaki G, Vázquez J. . J Infect. 2024; 89(6): 106335

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Dissociation of actin polymerization and lipid raft accumulation by ligation of the Inducible Costimulator (ICOS, CD278)

6. Y. Acosta, G. Ojeda, M. P. Zafra, I. Seren-Bernardone, A. Sánchez, U. Dianzani, P. Portolés y J. M. Rojo. Dissociation of actin polymerization and lipid raft accumulation by ligation of the Inducible Costimulator (ICOS, CD278). Inmunología, 2012, 31 (1): 4-12.

DOI

Genetic Characterization of Brucella spp.: Whole Genome Sequencing-Based Approach for the Determination of Multiple Locus Variable Number Tandem Repeat Profiles

Pelerito A, Nunes A, Grilo T, Isidro J, Silva C, Ferreira AC, Valdezate S, Núncio MS, Georgi E, Gomes JP. (2021) Genetic Characterization of Brucella spp.: Whole Genome Sequencing-Based Approach for the Determination of Multiple Locus Variable Number Tandem Repeat Profiles. 2021. Front Microbiol. 12;12:740068

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Evaluation of onchocerciasis seroprevalence in Bioko Island (Equatorial Guinea) after years of disease control programmes.

Hernández-González A, Moya L, Perteguer MJ, Herrador Z, Nguema R, Nguema J, Aparicio P, Benito A, Gárate T. Evaluation of onchocerciasis seroprevalence in Bioko Island (Equatorial Guinea) after years of disease control programmes. Parasit Vectors. 2016 Sep 20;9(1):509.

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A Small Non-Coding RNA Modulates Expression of Pilus-1 Type in Streptococcus pneumoniae

Acebo P, Herranz C, Bernal-Espenberger L, Gómez-Sanz A, Terron MC, Luque D and Amblar M. Microorganisms. 2021; 9:1883.

PUBMED DOI

Toll-like receptors in acute kidney injury

Vázquez-Carballo C, Guerrero-Hue M, García Caballero C, Rayego-Mateos S, Opazo-Rios L, Morgado-Pascual JL, Herencia-Bellido C, Vallejo-Mudarra M, Cortegano I, Gaspar ML, de Andrés B, Egido J, Moreno-Gutiérrez JA. Int J Mol Sci. 2021 Jan; 22(2): 816.

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List of staff

Información adicional

• Taxonomic study. Objective: Association of already described species to new clinical processes. Description of new bacterial species. 

• Sensitivity studies against new antituberculous drugs: Objective: To evaluate the antimicrobial activity of new compounds for human use in clinical strains of Mycobacterium tuberculosis and in other species of non-tuberculous mycobacteria, for subsequent application in the treatment of these infections. 

• Molecular epidemiology of tuberculosis. Objectives: Molecular characterization of the members of the M. tuberculosis complex. Transmission studies with special surveillance of MDR/XDR tuberculosis. 

• Development of new methods of identification and detection of resistance in mycobacteria. Objectives: Optimization and development of molecular techniques for the diagnosis and detection of resistance.

Content with Investigacion Genética Bacteriana .