García Esteban, María Teresa

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First Name
María Teresa
Last Name
García Esteban
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Biológicas
Genética, Fisiología y Microbiología
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Now showing 1 - 6 of 6
  • Publication
    Anti-melanogenic and Anti-inflammatory Activities of Hibiscus sabdariffa
    (Springer, 2022-02-09) Apaza Ticona, Luis Néstor; Pérez Uz, María Blanca; García Esteban, María Teresa; Aguilar Rico, Francisco; Slowing Barillas, Karla Verónica
    Hibiscus sabdariffa L., Malvaceae, is traditionally cultivated for its stem, leaves, calyces, and seeds as all parts have industrial, medicinal, and cosmetic applications. Likewise, there are many works on the biological properties of the aqueous extract of H. sabdariffa due to its high content of polyphenolic compounds. Using the Folin-Ciocalteu method, the total polyphenol content of an aqueous extract of a sample from Guatemala was found to be 15.97 ± 0.49 mg GAE/g. The presence of ten phenolic acids, ten flavonoids, and two anthocyanins was determined by 1 H NMR analysis. The anti-melanogenic activity assay of the aqueous extract showed inhibition of the tyrosinase activity (IC50 3.53 ± 0.16 μg/ml) and inhibition of the melanin production (IC50 3.90 ± 0.17 μg/ml) in the B16F10 cell line. Finally, the aqueous extract showed an inhibition of NO production with an IC50 of 4.72 ± 0.34 μg/ml and 3.62 ± 0.36 μg/ml in the RAW 264.7 and B16F10 cell lines, respectively. Our results allowed us to identify those polyphenolic compounds present in the aqueous extract of H. sabdariffa whose synergic effect increases the anti-melanogenic and anti-inflammatory properties of the aqueous extract.
  • Publication
    The Transcriptome of Streptococcus pneumoniae Induced by Local and Global Changes in Supercoiling
    (Frontiers Media, 2017) Campa, Adela G. de la; Ferrándiz, María José; Martín Galiano, Antonio J.; García Esteban, María Teresa; Tirado Vélez, José M.
    The bacterial chromosome is compacted in a manner optimal for DNA transactions to occur. The degree of compaction results from the level of DNA-supercoiling and the presence of nucleoid-binding proteins. DNA-supercoiling is homeostatically maintained by the opposing activities of relaxing DNA topoisomerases and negative supercoil-inducing DNA gyrase. DNA-supercoiling acts as a general cis regulator of transcription, which can be superimposed upon other types of more specific trans regulatory mechanism. Transcriptomic studies on the human pathogen Streptococcus pneumoniae, which has a relatively small genome (∼2 Mb) and few nucleoid-binding proteins, have been performed under conditions of local and global changes in supercoiling. The response to local changes induced by fluoroquinolone antibiotics, which target DNA gyrase subunit A and/or topoisomerase IV, involves an increase in oxygen radicals which reduces cell viability, while the induction of global supercoiling changes by novobiocin (a DNA gyrase subunit B inhibitor), or by seconeolitsine (a topoisomerase I inhibitor), has revealed the existence of topological domains that specifically respond to such changes. The control of DNA-supercoiling in S. pneumoniae occurs mainly via the regulation of topoisomerase gene transcription: relaxation triggers the up-regulation of gyrase and the down-regulation of topoisomerases I and IV, while hypernegative supercoiling down-regulates the expression of topoisomerase I. Relaxation affects 13% of the genome, with the majority of the genes affected located in 15 domains. Hypernegative supercoiling affects 10% of the genome, with one quarter of the genes affected located in 12 domains. However, all the above domains overlap, suggesting that the chromosome is organized into topological domains with fixed locations. Based on its response to relaxation, the pneumococcal chromosome can be said to be organized into five types of domain: up-regulated, down-regulated, position-conserved non-regulated, position-variable non-regulated, and AT-rich. The AT content is higher in the up-regulated than in the down-regulated domains. Genes within the different domains share structural and functional characteristics. It would seem that a topology-driven selection pressure has defined the chromosomal location of the metabolism, virulence and competence genes, which suggests the existence of topological rules that aim to improve bacterial fitness.
  • Publication
    Service-Learning, Movies, and Infectious Diseases: Implementation of an Active Educational Program in Microbiology as a Tool for Engagement in Social Justice
    (Frontiers Media, 2021-06-29) Linares Gómez, María; López Ejeda, Noemí; Álvarez Vázquez, Mª Pilar; Culebras López, Esther; Díaz, E; García Esteban, María Teresa; Majano, C.; Morales, ML; Rodríguez García, A.; Rodríguez-Avial, Iciar; Utrilla, C.L.; Valenzuela, M.V.; Valderrama Conde, María José
    Service-Learning is an educational methodology that allows student learning while addressing community needs. A program in microbiology and infectious diseases was implemented in Universidad Complutense de Madrid, Spain. University lecturers, clinical microbiologists, doctorate students, and undergraduates from several Bachelor Degrees and courses worked in an interdisciplinary team along with social institutions that attend disadvantaged persons. Using commercial movies that deal with infectious diseases, the students learn clinical microbiology, prepare divulgation materials, visit social centers to accompany, and help others to know about illnesses and prevention. The program was developed through two academic years and involved 58 voluntary students, 13 teachers and tutors, and 4 social entities as community partners. Postsurvey evaluation of the program revealed a highly satisfactory achievement of goals: acquiring scientific and personal competencies by university students, including critical analysis and science diffusion, solving problems or collaborative team working, and contributing, together with the tutors, to the social responsibility of the university.
  • Publication
    Antibacterial activity of a DNA topoisomerase I inhibitor versus fluoroquinolones in Streptococcus pneumoniae
    (Public Library of Science, 2020-11-03) Valenzuela Naveda, Myriam; Domenech Lucas, Mirian; Mateos-Martínez, Patricia; González-Camacho, Fernando; Campa, Adela G. de la; García Esteban, María Teresa
    The DNA topoisomerase complement of Streptococcus pneumoniae is constituted by two type II enzymes (topoisomerase IV and gyrase), and a single type I enzyme (topoisomerase I). These enzymes maintain the DNA topology, which is essential for replication and transcription. While fluoroquinolones target the type II enzymes, seconeolitsine, a new antimicrobial agent, targets topoisomerase I. We compared for the first time the in vitro effect of inhibition of topoisomerase I by seconeolitsine and of the type II topoisomerases by the fluoroquinolones levofloxacin and moxifloxacin. We used three isogenic non-encapsulated strains and five non-vaccine serotypes isolates belonging to two circulating pneumococcal clones, ST638 (2 strains) and ST1569V (3 strains). Each group contained strains with diverse susceptibility to fluoroquinolones. Minimal inhibitory concentrations, killing curves and postantibiotic effects were determined. Seconeolitsine demonstrated the fastest and highest bactericidal activity against planktonic bacteria and biofilms. When fluoroquinolone-susceptible planktonic bacteria were considered, seconeolitsine induced postantibiotic effects (1.00−1.87 h) similar than levofloxacin (1.00−2.22 h), but longer than moxifloxacin (0.39 −1.71 h). The same effect was observed in sessile bacteria forming biofilms. Seconeolitsine induced postantibiotic effects (0.84−2.31 h) that were similar to those of levofloxacin (0.99 −3.32 h) but longer than those of moxifloxacin (0.89−1.91 h). The greatest effect was observed in the viability and adherence of bacteria in the postantibiotic phase. Seconeolitsine greatly reduced the thickness of the biofilms formed in comparison with fluoroquinolones: 2.91 ± 0.43 μm (seconeolitsine), 7.18 ± 0.58 μm (levofloxacin), 17.08 ± 1.02 μm (moxifloxacin). When fluoroquinolone-resistant bacteria were considered, postantibiotic effects induced by levofloxacin and moxifloxacin, but not by seconeolitsine, were shorter, decreasing up to 5-fold (levofloxacin) or 2-fold (moxifloxacin) in planktonic cells, and up to 1.7 (levofloxacin) or 1.4-fold (moxifloxacin) during biofilm formation. Therefore, topoisomerase I inhibitors could be an alternative for the treatment of pneumococcal diseases, including those caused by fluoroquinolone-resistant isolates.
  • Publication
    Influence of malnutrition upon all-cause mortality among children in Swaziland
    (Sociedad Española de Endocrinología y Nutrición, 2017-04) Acevedo, Paula; García Esteban, María Teresa; López Egeda, Noemí; Gómez, Amador; Marrodán Serrano, Dolores
    Objective: To analyze the effect of the type of malnutrition, sex, age and the presence of edema upon all-cause mortality in children under 5 years of age. Material and methods: A cross-sectional study was conducted during 2010 and 2011 in Swaziland. Sex, age, weight and height were taken to classify nutritional status according to the 2006 WHO growth standards: stunting (low height for age), wasting (low weight for height or low body mass index for age) and underweight (low weight for age). The sample (309 boys and 244 girls under 5 years of age) was analyzed by sex and age groups (under and equal/over 12 months). The association between variables was evaluated using the 2 test. Cox regression analysis (HR, 95% CI) was used to assess the likelihood of mortality. Results: The mortality risk in malnourished children under one year of age was lower among females and increased in the presence of severe edema. Wasting combined with underweight increased the mortality risk in children under 12 months of age 5-fold, versus 11-fold in older children. The combination of stunting, wasting and underweight was closely associated to mortality. Stunting alone (not combined with wasting) did not significantly increase the mortality risk. Conclusions: Sex, severe edema and wasting are predictors of mortality in malnourished children. Regardless of these factors, children with deficiencies referred to weight for height and weight for age present a greater mortality risk in comparison with children who present stunting only.
  • Publication
    Enfermedades Infecciosas: Cámaras y ... ¡Acción!
    (2015) García Esteban, María Teresa; Valderrama Conde, María José; Benitez Rico, Laura; Patiño Álvarez, Belén; Martín Cereceda, Mercedes; Fúster Siebert, Vicente; Marrodan Serrano, Dolores; Muñoz Araujo, Benito; Refoyo Román, Pablo; Gómez Sanchez, José Francisco; Conejero Meca, Francisco; Gómez Flechoso, María Angeles; Sánchez Hontana, Alicia
    La salud es un recurso, un derecho y un motor del desarrollo económico y social. El conocimiento de las Enfermedades Infecciosas necesita de un enfoque multidisciplinar que aborde el estudio de su etiología, epidemiología, prevención, detección y control desde un punto de vista clínico y ambiental. En los Grados en Biología y Bioquímica (Facultades de Biología y Químicas) existen varias asignaturas relacionadas directamente con este tema. El proyecto de innovación docente propuesto planteó un abordaje multidisciplinar para que el alumno relacionara e integrara conceptos y dispusiera de enseñanzas complementarias que reforzaran los cononocimientos adquiridos en el aula además de acercarle a otros aspectos de la realidad de las Enfermedades Infecciosas. Para ello, propuso usar una herramienta didáctica familiar y cercana a los alumnos, el cine. Con ello, se pretendía conseguir un aprendizaje instrumentado que permitiera a los alumnos apreciar la importancia de las Enfermedades Infecciosas en el ámbito de la Biología y la Salud Pública. También se buscaba que los estudiantes fueran capaces de construir su propio conocimiento, descubriendo a través de las películas las enfermedades infecciosas no solo como hecho biológico sino como una experiencia individual y un fenómeno social merecedoras de un análisis crítico y rigurosos. Además se quería reforzar el aprendizaje significativo del alumno al usar actividades dinámicas y motivadoras y la adquisición de competencias transversales del Grado, así como el aprendizaje en inglés y el aprendizaje on-line. Así, se propuso un proyecto con un ámbito de aplicación amplio, que sirviera para mejorar el proceso enseñanza-aprendizaje, que contribuyera a la formación del profesorado, al desarrollo de contenidos reutilizables, que reforzara la diversidad y que promoviera el trabajo colaborativo y la cultura de calidad en la comunidad universitaria con una finalidad de servicio comunitario