87 results on '"Borrego I"'
Search Results
2. Kernel-based methods for combining information of several frame surveys
- Author
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Sánchez-Borrego, I., Arcos, A., and Rueda, M.
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- 2019
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3. Nonparametric Estimation to Reconstruct the Deformation History of an Active Fold in the Caspian Basin
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Sánchez-Borrego, I. R., Soto, J. I., Rueda, M., and Betancor, I. Santos
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- 2016
- Full Text
- View/download PDF
4. Fibrin, Bone Marrow Cells And Macrophages Interactively Modulate Cardiomyoblast Fate: An In Vitro Study
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Borrego, I, primary, Frobert, A, additional, Cook, S, additional, Dengjel, J, additional, and Giraud, MN, additional
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- 2022
- Full Text
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5. Post-stratified calibration method for estimating quantiles
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Martínez, S., Rueda, M., Arcos, A., Martínez, H., and Sánchez-Borrego, I.
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- 2011
- Full Text
- View/download PDF
6. Nonparametric estimation with mixed data types in survey sampling
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Sánchez-Borrego, I., Opsomer, J. D., Rueda, M., and Arcos, A.
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- 2014
- Full Text
- View/download PDF
7. Using nonparametric methods in social surveys: an empirical study
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Rueda, M., Sánchez-Borrego, I., and Arcos, A.
- Published
- 2013
- Full Text
- View/download PDF
8. An approximation method to derive confidence intervals for quantiles with some applications
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Rueda, M., Arcos, A., Sánchez-Borrego, I., and Muñoz, J. F.
- Published
- 2012
- Full Text
- View/download PDF
9. Nonparametric methods in sample surveys. Application to the estimation of cancer prevalence
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Sánchez-Borrego, I., Rueda, M., and Muñoz, J. F.
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- 2012
- Full Text
- View/download PDF
10. Model-calibration estimation of the distribution function using nonparametric regression
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Rueda, M., Sánchez-Borrego, I., Arcos, A., and Martínez, S.
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- 2010
- Full Text
- View/download PDF
11. A predictive estimator of finite population mean using nonparametric regression
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Rueda, M. and Sánchez-Borrego, I. R.
- Published
- 2009
- Full Text
- View/download PDF
12. New methodologies in statistics: a different way of studying SPSS
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Lara-Porras, A.M., Ramos-Abalos, E., Raya-Miranda, R., Sanchez-Borrego, I., and Tarifa-Blanco, J.A.
- Published
- 2009
13. Local linear kernel estimation of the discontinuous regression function
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Sánchez-Borrego, I. R., Martínez-Miranda, M. D., and González-Carmona, A.
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- 2006
- Full Text
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14. As a biopatch, fibrin and bone marrow-derived cells modulate macrophage polarization and cardiomyobasts proliferation
- Author
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Borrego, I, primary, Frobert, A, additional, Cook, S, additional, and Giraud, M.N, additional
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- 2020
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15. Kernel-based methods for combining information of several frame surveys
- Author
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Sánchez-Borrego, I., primary, Arcos, A., additional, and Rueda, M., additional
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- 2018
- Full Text
- View/download PDF
16. P2536Cardiac bone marrow-derived cell-based therapy associated with scaffold for heart regeneration
- Author
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Borrego, I., primary, Frobert, A., additional, Valentin, J., additional, Ajalbert, G., additional, Roth, V., additional, Fellay, B., additional, Cook, S., additional, and Giraud, M.N., additional
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- 2017
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17. Shifts in microbial community structure and function in light- and dark-grown biofilms driven by warming
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Romaní i Cornet, Anna M., Borrego i Moré, Carles, Díaz Villanueva, Verónica, Freixa Casals, Anna, Gich Batlle, Frederic, Ylla i Monfort, Irene, and Ministerio de Ciencia e Innovación (Espanya)
- Subjects
Microbial ecology ,Biofilms ,biochemical phenomena, metabolism, and nutrition ,Ecologia microbiana - Abstract
Biofilms are dynamic players in biogeochemical cycling in running waters and are subjected to environmental stressors like those provoked by climate change. We investigated whether a 2 degrees C increase in flowing water would affect prokaryotic community composition and heterotrophic metabolic activities of biofilms grown under light or dark conditions. Neither light nor temperature treatments were relevant for selecting a specific bacterial community at initial phases (7-day-old biofilms), but both variables affected the composition and function of mature biofilms (28-day-old). In dark-grown biofilms, changes in the prokaryotic community composition due to warming were mainly related to rotifer grazing, but no significant changes were observed in functional fingerprints. In light-grown biofilms, warming also affected protozoan densities, but its effect on prokaryotic density and composition was less evident. In contrast, heterotrophic metabolic activities in light-grown biofilms under warming showed a decrease in the functional diversity towards a specialized use of several carbohydrates. Results suggest that prokaryotes are functionally redundant in dark biofilms but functionally plastic in light biofilms. The more complex and self-serving light-grown biofilm determines a more buffered response to temperature than dark-grown biofilms. Despite the moderate increase in temperature of only 2 degrees C, warming conditions drive significant changes in freshwater biofilms, which responded by finely tuning a complex network of interactions among microbial populations within the biofilm matri This study was funded by the Spanish Ministry of Economy and Competitiveness, project FLUMED-HOTSPOTS (CGL2011-30151-C02-01). V. Diaz Villanueva participated in this project supported by FONCYT (Argentina) (PICT-2007-01747) and CONICET (PIP 114-201101-00304)
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- 2014
18. GIST rectal
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Valera Sánchez, Z., Sánchez Gil, J. M., Díaz Aunión, C., Blanco, M. A., Socas Macías, M., and Serrano Borrego, I.
- Published
- 2008
19. Effect of parameters on alkaline extraction of annatto colorant. Part 1
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García, Y., Núñez de Villavicencio, M., Rodríguez, J. L., Borrego, I., and Cruz, L.
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Chemical concentration ,Annatto (tree) ,Extraction (salts) ,Temperature ,Solvents ,Hydroxides ,Sodium hydroxide - Abstract
Se investigó la influencia de la temperatura (50 y 60 ºC), la relación disolvente-semillas (3:1 y 5:1), la agitación (100 y 300 rev/min) y la concentración de hidróxido de sodio (0,5 y 1,0 N) en la extracción de colorante de bija. La extracción se favoreció con el aumento de la temperatura y la disminución de la concentración de sosa. La agitación prácticamente no causó efectos en los niveles de extracción. Las relaciones disolvente-semillas ensayadas no tuvieron incidencia en la cantidad de pigmentos extraída. The effect of temperature (50 and 60ºC), solvent to seeds ratio (3:1 and 5:1), agitation (100 and 300 rpm) and sodium hydroxide concentration (0.5 and 1.0 N) on annatto extraction were investigated. The extraction was improved with the temperature increase and decrease in sodium hydroxide concentration. Agitation practically did not affect the levels of extraction. Solvent to seed ratio had no incidence on the amount of pigments. Published annatto colorants natural colorants agitation
- Published
- 2008
20. Nonparametric estimation with mixed data types in survey sampling
- Author
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Sánchez-Borrego, I., primary, Opsomer, J. D., additional, Rueda, M., additional, and Arcos, A., additional
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- 2013
- Full Text
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21. Arquitectura automatizada de comercio electrónico
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Borrego, I., Hernández, M. J., García-Peñalvo, Francisco J., Curto Diego, María Belén, Moreno Rodilla, Vidal, and Hernández Simón, Juan Andrés
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World Wide Web ,comercio electrónico ,Electronic commerce ,Catálogo de productos ,XML ,Interacción hombre-máquina (Informática) ,Human-computer interaction ,XML (Lenguaje de marcas) - Abstract
El objetivo de este trabajo es el desarrollo de una arquitectura concreta de comercio electrónico que integre servicios B2B y B2C, facilitando la incorporación de las empresas a este ámbito de negocio. Se pretende proporcionar un entorno automático que permita a una empresa diseñar su propia estrategia de negocio en Internet, minimizando las tareas demantenimiento del sitio de comercio electrónico, reduciendo así los costes de la expansión de la empresa.
- Published
- 2001
22. Herramienta automática para la generación de catálogos de venta en internet
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Hernández, M.J., Borrego, I., García-Peñalvo, Francisco J., Curto Diego, María Belén, Moreno García, María Navelonga, and Hernández Simón, Juan Andrés
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Electronic commerce ,Comercio electrónico ,Catálogo de productos ,Diseño de productos ,Software - Abstract
En este trabajo se muestra la génesis de un proyecto orientado a construir una herramienta software especializada, que permita automatizar, hasta cierto punto, el diseño de catálogos de productos para su posteriorpublicación y venta en Internet. Este proceso de automatización tiene como fin último que una empresa pueda entrar e n el mundo del comercio electrónico sin necesidad de que sus responsables tengan unos conocimientos avanzados sobreinformática.
- Published
- 2001
23. Heterogeneïtat pigmentària en bacteris fotosintètics verds: fisiologia i significació ecològica
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Borrego i Moré, Carles, Garcia-Gil, L. J., and Universitat de Girona. Institut d'Ecologia Aquàtica
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Tesis i dissertacions acadèmiques ,Bacterias fotosintéticas ,Pigments fotosintètics ,Bacterioclorofila ,574 - Ecologia general i biodiversitat ,Bacterioclorofil·la ,Bacteris fotosintetitzadors ,macromolecular substances ,579 - Microbiologia ,Pigmentos fotosintéticos ,Photosynthetic bacteria ,Photosynthetic pigments ,sense organs ,Bacteriochlorophyll ,human activities - Abstract
Green bacteria possess one of the most complexes antenna systems within the group of the photosynthetic microorganisms. One reason for this complexity is the high diversity of pigments antenna, the bacteriochlorophylls (BChls c, d or e), consisting of a mixture of various forms regularly arranged within the antenna units (the chlorosomes). This pigment diversity makes difficult the accurate analysis and identification of the different bacteriochlorophylls forms by the conventional spectrophotometrical techniques, Els bacteris verds posseeixen un dels sistemes antena més complexes dins el grup dels microorganismes fotosintètics. Una de les raons d’aquesta complexitat és l’elevada diversitat de pigments antena, especialment pel que fa a les bacterioclorofil•les (BCIs c, d o e). Cadascuna d’aquestes BCIs, que tenen diferents estructures i propietats òptiques, es composa d’una mescla de diverses formes homòlogues disposades ordenadament a l’interior de les unitats antena (clorosomes). Aquesta diversitat pigmentària dificulta enormement l’anàlisi i identificació d’aquests pigments mitjançant les tècniques espectrofotomètriques tradicionals
- Published
- 1996
24. Using nonparametric methods in social surveys: an empirical study
- Author
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Rueda, M., primary, Sánchez-Borrego, I., additional, and Arcos, A., additional
- Published
- 2011
- Full Text
- View/download PDF
25. A quantile estimator under two-phase sampling for stratification
- Author
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Rueda, M., primary, Muñoz, J. F., additional, and Sánchez-Borrego, I., additional
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- 2011
- Full Text
- View/download PDF
26. An approximation method to derive confidence intervals for quantiles with some applications
- Author
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Rueda, M., primary, Arcos, A., additional, Sánchez-Borrego, I., additional, and Muñoz, J. F., additional
- Published
- 2011
- Full Text
- View/download PDF
27. Nonparametric methods in sample surveys. Application to the estimation of cancer prevalence
- Author
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Sánchez-Borrego, I., primary, Rueda, M., additional, and Muñoz, J. F., additional
- Published
- 2010
- Full Text
- View/download PDF
28. Separation of bacteriochlorophyll c and chlorophil a from mixed extracts by reversed-phase high performance liquid chromatography
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Borrego i Moré, Carles and Garcia-Gil, L. J.
- Published
- 1993
29. Mean estimation in the presence of change points
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Rueda, M., primary, Sánchez-Borrego, I., additional, and Arcos, A., additional
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- 2009
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30. Moderated Posters: Sudden cardiac death
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Kwasniewski, W., primary, Filipecki, A., additional, Orszulak, W., additional, Urbanczyk, D., additional, Szydlo, K., additional, Trusz Gluza, M., additional, Borleffs, C. J. W., additional, Van Rees, J. B., additional, Van Welsenes, G. H., additional, Van Erven, L., additional, Van Bommel, R. J., additional, Van Der Velde, E. T., additional, Bax, J. J., additional, Schalij, M. J., additional, Jimenez-Candil, J., additional, Ruiz, M., additional, Morinigo, J., additional, Martin, A., additional, Ledesma, C., additional, Martin-Luengo, C., additional, Cozar-Leon, R., additional, Diaz-Infante, E., additional, Prado-Gotor, B., additional, Nieto, P., additional, Maldonado, J., additional, Borrego, I., additional, Cruz, J. M., additional, Satomi, K., additional, Yamada, Y., additional, Okamura, H., additional, Noda, T., additional, Shimizu, W., additional, Suyama, K., additional, Aihara, N., additional, Kamakura, S., additional, Hatzinikolaou-Kotsakou, E., additional, Moschos, G., additional, Beleveslis, T. H., additional, Reppas, E., additional, Kotsakou, M., additional, Tsakiridis, K., additional, Nageh, M. F., additional, Kim, J. J., additional, Yao, J., additional, Deering, T. F., additional, Epstein, A., additional, Goldman, D., additional, Greenberg, S., additional, Dalal, Y., additional, Kreuz, J., additional, Balta, O., additional, Lickfett, L., additional, Nickenig, G., additional, Schwab, J., additional, Horlbeck, F. W., additional, Bitzen, A., additional, Liliegren, N., additional, Jegorova, A., additional, and Schwab, J. O., additional
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- 2009
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31. A predictive estimator of finite population mean using nonparametric regression
- Author
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Rueda, M., primary and Sánchez-Borrego, I. R., additional
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- 2008
- Full Text
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32. A new method for solving the problem of the mean estimation when the underlying regression function is discontinuous
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Rueda, M., primary, Sánchez-Borrego, I., additional, and González, A., additional
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- 2008
- Full Text
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33. GIST rectal
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Valera Sánchez, Z., primary, Sánchez Gil, J. M., additional, Díaz Aunión, C., additional, Blanco, M. A., additional, Socas Macías, M., additional, and Serrano Borrego, I., additional
- Published
- 2008
- Full Text
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34. Diagnóstico de recurrencia mediante FDG-PET en un caso clínico de schwannoma maligno
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Santaella, Y., primary, Borrego, I., additional, López, J., additional, Ortiz, M.J., additional, and Vázquez, R., additional
- Published
- 2005
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35. An optimal technique for ECG noise reduction in real time applications.
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Elena, M.M., Quero, J.M., and Borrego, I.
- Published
- 2006
36. Horizontal distribution of phototropic bacterial population in an irregularly-shaped meromictic basin of Banyoles lake (Banyoles, Spain)
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Borrego i Moré, Carles, Garcia-Gil, L. J., Hugas, L., and Casamitjana, Xavier
- Published
- 1988
37. The role of biofilms as environmental reservoirs of antibiotic resistance
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Balcázar, José Luis, Subirats, Jéssica, Borrego i Moré, Carles, and Ministerio de Ciencia e Innovación (Espanya)
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Microbial ecology ,Antibiotics ,Drug resistance in microorganisms ,Biofilms ,Microorganismes -- Resistència als medicaments ,Antibiòtics ,Ecologia microbiana - Abstract
Antibiotic resistance has become a significant and growing threat to public and environmental health. To face this problem both at local and global scales, a better understanding of the sources and mechanisms that contribute to the emergence and spread of antibiotic resistance is required. Recent studies demonstrate that aquatic ecosystems are reservoirs of resistant bacteria and antibiotic resistance genes as well as potential conduits for their transmission to human pathogens. Despite the wealth of information about antibiotic pollution and its effect on the aquatic microbial resistome, the contribution of environmental biofilms to the acquisition and spread of antibiotic resistance has not been fully explored in aquatic systems. Biofilms are structured multicellular communities embedded in a self-produced extracellular matrix that acts as a barrier to antibiotic diffusion. High population densities and proximity of cells in biofilms also increases the chances for genetic exchange among bacterial species converting biofilms in hot spots of antibiotic resistance. This review focuses on the potential effect of antibiotic pollution on biofilm microbial communities, with special emphasis on ecological and evolutionary processes underlying acquired resistance to these compounds This work has been supported by the European Communities seventh Framework Programme Funding under Grant agreement no. 603629-ENV-2013-6.2.1-GLOBAQUA. JB acknowledges the Ramon y Cajal research fellowship (RYC-2011-08154) from the Spanish Ministry of Economy and Competitiveness
38. Phylogenetic characterization and quantification of ammonia-oxidizing archaea and bacteria from Lake Kivu in a long-term microcosm incubation
- Author
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Plasencia, Anna, Gich Batlle, Frederic, Fillol Homs, Mireia, Borrego i Moré, Carles, Ministerio de Ciencia y Tecnología (Espanya), Ministerio de Educación y Ciencia (Espanya), and Ministerio de Ciencia e Innovación (Espanya)
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Microbiologia d'aigua dolça ,Freshwater microbiology ,Microbiology -- Cultures and culture media ,Microbiologia -- Cultius i medis de cultiu - Abstract
A microcosm cultivation-based method was set up to investigate the growth of ammonia-oxidizing archaea (AOA), isolated from a water sample acquired at a depth of 50 m from the northern basin of Lake Kivu. For this purpose, both CARD-FISH and qPCR targeting of archaeal 16S rRNA and amoA genes were used. Archaeal cell growth at the end of the 246-day microcosm experiment accounted for 35 % of the SybrGold-stained cells, which corresponded to 6.61 × 106 cells/ml and 1.76 ± 0.09 × 106 archaeal 16S rRNA gene copies/ml. Clone libraries and DGGE fingerprinting confirmed the dominance of AOA phylotypes in the archaeal community microcosm. The majority of the identified archaeal 16S rRNA gene sequences in the clone libraries were affiliated with Thaumarchaeota Marine Group 1.1a. Subsequent cultivation of the AOA community on deep-well microtiter plates in medium containing different carbon sources to stimulate archaeal growth failed to show significant differences in archaeal abundance (ANOVA t14 = -1.058, P = 0.308 and ANOVA t14 = 1.584, P = 0.135 for yeast extract and simple organic acids, respectively). The lack of growth stimulation by organic compounds is in concordance with the oligotrophic status of Lake Kivu. Finally, the addition of antibiotics to the growth medium resulted in archaeal cell counts that were significantly lower than those obtained from cultures in antibiotic-free medium This work was founded by the Spanish Government through projects CRENYC (CGL2006-12058-C02-01), ARKI (CGL2007-29823-E) and ARCANOX (CGL2009-13318-C02-02). A.P.C. and M.F.H. are recipients of pre-doctoral fellowships from the Catalan (2006FI-109) and theSpanish (FPI BES-2010-035225) Governments, respectively
39. Pathologic Complete Responses After Chemotherapy Plus Figitumumab in Stage IV Non-Small-Cell Lung Cancer.
- Author
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Corral J, López-Villalobos JL, Gomez-Izquierdo L, Borrego I, and Paz-Ares L
- Published
- 2011
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40. The impact of influenza vaccination in the reduction of morbidity and in the exacerbation in asthmatic patients
- Author
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Oropesa, Suset, Acosta, B., Piñón, A., Andreus, H., Hernández, B., Borrego, I., and Llanes, J.
- Subjects
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INFLUENZA , *ASTHMA , *VACCINATION , *RESPIRATORY infections - Abstract
Background: Vaccine campaigns against flu in Cuba increased for those groups at risk of developing complications, such as persons with chronic heart or lung diseases, including asthmatics. Several statements justify the study of asthmatic persons with the objective of reducing morbidity, mortality, exacerbations of asthma and the use of antibiotics. Humoral response of a group of asthmatic persons, generated by the commercial vaccine Agrippal S1 (Biocine s.p.a., Siena, Italy), was evaluated for the influenza virus during the 2000–2001 season. The efficacy and effectiveness of the influenza vaccine to prevent clinical flu infection and exacerbations in a population with asthma (one vaccine dose) was studied. Materials and methods: The study was carried out during the 2000–2001 season, with Agrippal S1 (Chiron Vaccines), containing the influenza strains (formula recommended by WHO for this season). In all, 45 patients received one dose. The sera were measured before vaccination and 1 month after by hemagglutination test (IH). Statistical analysis was made using the Student''s test. Results: The IH test demonstrated the capacity of the vaccine to stimulate the production of antihemagglutinin antibody levels. The positive cases for the subtypes H3N2 and H1N1 were 57.8% before vaccination and 95.6% and 84.4% after vaccination; and, for type B, 4.4% before and 44.4% after vaccination. There was an increment in the GMT subtype, AH3N2, from 11.7 to 39.4; AH1N1 from 14.9 to 76.2 and type B from 5.2 to 9.7. The family doctor did not report any cases of acute flu or asthma crisis during the year after vaccination, reduction of the morbidity, hospitalizations due to pneumonia and reduction of antibiotic use. Conclusions: The vaccination (one dose) achieved satisfactory levels of antibodies for the strains H3N2 and H1N1. These were low for type B. The real results of the vaccination were very effective. There were neither acute cases of flu nor exacerbations of asthma after vaccination during the following year. The study concluded that the inactivated influenza vaccine is safe to administer to adults and children with asthma, including those with severe asthma.In Cuba, influenza vaccination rates increased, demonstrating the convenience of annual vaccination in high-risk groups. [Copyright &y& Elsevier]
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- 2004
- Full Text
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41. Influence of anthropogenic pollution on the prevalence, maintenance and spread of antibiotic resistance in aquatic microbial communities
- Author
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Subirats Medina, Jessica, Borrego i Moré, Carles, Balcázar, José Luis, and Universitat de Girona. Institut Català de Recerca de l'Aigua
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Resistència als antibiòtics ,Comunidades microbianas ,Contaminació antropogènica ,Antibiotic resistance ,Anthropogenic pollution ,Resistencia a los antibióticos ,Biofilm ,574 - Ecologia general i biodiversitat ,Microbial communities ,579 - Microbiologia ,Genes de resistencia a los antibióticos ,Contaminación antropogénica ,Antibiotic resistance genes ,Comunitats microbianes ,Gens de resistència als antibiòtics - Abstract
This Thesis demonstrates that microorganisms derived from wastewater are the 2/2 main contributors to antibiotic resistance (AR) in the environment. Once there, the background chemical contamination with antibiotic residues and other pharmaceutical compounds set the optimal conditions for the accumulation and spread of resistance genes among resident bacterial communities. We also prove that nutrients, in combination with emerging contaminants, act synergically on the dissemination of some antibiotic resistance genes (ARGs) within bacterial communities. According to our results, streambed biofilms appear as useful biosensors of the effect of wastewater discharges on the prevalence of AR in surface waters. Finally, we also proved that bacteriophages (viruses that infect bacteria) accumulate ARGs and thus they may have an important role on the dissemination of AR in aquatic environments La present Tesi demostra que els microorganismes procedents de les aigües residuals són el principal factor implicat en distribuir la resistència als antibiòtics (AR) al medi natural i que la contaminació de fons per antibiòtics i altres fàrmacs estableix les condicions òptimes per la seva acumulació i disseminació entre les comunitats microbianes residents. També es demostra aquí que els nutrients, en combinació amb diferents contaminants emergents, actuen en sinergia per estimular la disseminació d'alguns gens de resistència als antibiòtics (ARGs) en les comunitats bacterianes. Segons els nostres resultats, els biofilms del llit fluvial esdevenen útils com a biosensors de l’efecte de les descàrregues d’aigües residuals en la prevalença de la AR en aigües superficials. Finalment, aquesta tesi també aporta resultats que proven que els bacteriòfags (virus que infecten bacteris) acumulen ARGs i, per tant, poden tenir un paper important en la disseminació de la AR en els ambients aquàtics
- Published
- 2018
42. Factors affecting the distribution, abundance and diversity of uncultured archaeal groups in freshwater sediments
- Author
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Compte Port, Sergi, Borrego i Moré, Carles, and Universitat de Girona. Institut Català de Recerca de l'Aigua
- Subjects
574 - Ecologia general i biodiversitat ,Arqueas ,579 - Microbiologia ,Archaea ,Sediments ,Sedimentos ,Freshwater ,gen 16S rRNA ,Agua dulce ,16S rRNA gene ,Arqueus ,Aigua dolça ,Bathyarchaeota ,Thermoplasmata - Abstract
Archaea are abundant in extreme environments but they are also a prevalent component of microbial communities in soils, marine or freshwater plankton and sediments. Many studies highlighted the prominent role of marine sedimentary Archaea in global nutrient cycles. Less information is available, however, on the diversity, abundance and ecological role of Archaea in freshwater sediments. A serious pitfall for the study of Archaea is their low cultivability under laboratory-controlled conditions thus constraining the progress towards the complete understanding of their metabolic capabilities and ecological functions. Most of the work is thus based on molecular techniques that allow the identification and quantification of target microorganisms without their cultivation. In this PhD project, we applied a combination of high-throughput sequencing and quantitative PCR to investigate the distribution, abundance and composition of archaeal communities in sediments from different freshwater systems (lakes, lagoons and reservoirs encompassing a wide range of conditions and typologies). The work has been focused in two archaeal groups consistently found, and especially abundant, in sediments: the phylum Bathyarchaeota and the class Thermoplasmata Els arqueus abunden en ambients extrems però també són un component rellevant dels sòls, del plàncton oceànic i lacustre i dels sediments. Molts estudis han destacat la importància dels arqueus en els cicles de nutrients dels sediments marins tant a escala local com global. En canvi, es disposa de menys informació sobre la diversitat, abundància i paper que juguen els arqueus en sediments d’aigua dolça a excepció dels metanògens. Com a dificultat afegida, la majoria d’arqueus sedimentaris no s’han pogut cultivar encara al laboratori, el que dificulta el seu estudi. La solució a aquests problemes passa per l’aplicació de tècniques moleculars que permeten la identificació i recompte dels microorganismes diana sense necessitat de cultivar-los. En aquesta tesi s’han combinat diferents tècniques moleculars (seqüenciació massiva i PCR quantitativa) per a conèixer la distribució, abundància i composició de les comunitats d’arqueus en sediments de sistemes aquàtics d’aigua dolça (llacs, llacunes i embassaments amb diferents condicions i tipologies). La tesi s’ha centrat en dos grups d’arqueus que són ubics i especialment abundants en sediments: el fílum Bathyarchaeota i la classe Thermoplasmata
- Published
- 2018
43. Teràpia fàgica com alternativa als antibiòtics: passat, present i futur
- Author
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Arrahaoui Douiri, Samira, Universitat de Girona. Facultat de Ciències, and Borrego i Moré, Carles
- Subjects
Drug resistance in microorganisms ,Antibiotics ,Microorganismes -- Resistència als medicaments ,Antibiòtics ,Bacteriophages ,Bacteriòfags - Abstract
Antibiotic resistance is a global health concern due to the increase in the number of multidrug resistant pathogens and the few available therapeutic alternatives to combat them. Non-antibiotic therapies are receiving attention as a viable alternative to treat infections caused by resistant pathogens. One of them is the therapeutic use of bacteriophages to target specific bacterial pathogens, the so-called “phage therapy”. Bacteriophages are viruses that infect bacteria and, according to recent studies, they are the most abundant biological entities in our planet. Phages have a major role in ecosystems and contribute to the evolution of their hosts. The first studies on phage therapy dated back from the early nineteenth century, but in the last decades these studies notably increased. Phage therapy has recently been re-discovered after being forgotten in the last fifty years due to the success of antibiotics in human medicine. Before the introduction of these drugs, in 1943, phages had already been used to treat infections caused by bacterial pathogens in the former Soviet Union and Eastern Europe. The results of these studies were published in non-English journals (Russia and Poland) and, therefore, they were not widely distributed in the scientific community. However, the current rise on the occurrence of multiresistant pathogens, especially strains of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa, has reignited the interest on phage therapy. Recent promising results have led the scientific community to face the future with optimism if phage therapy will be finally applied at larger scales. These benefits have been achieved on the basis of a better knowledge on phage biology, new and optimized technologies to purify phages and their innocuousness to both animals and humans
- Published
- 2018
44. Insights into the distribution and ecological role of members of the archaeal Phylum Bathyarchaeota. From the global to the local scale
- Author
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Fillol Homs, Mireia, Borrego i Moré, Carles, and Universitat de Girona. Institut d'Ecologia Aquàtica
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Tesis i dissertacions acadèmiques ,GDCT ,Uncultured archaea ,579 - Microbiologia ,Phylum Bathyarchaeota ,Miscellaneous Crenarchaeotic Group ,Ecologia microbiana ,Anoxic sediments ,Microbial ecology ,Arquea no cultivadas ,Sedimentos anóxicos ,Fílum Bathyarchaeota ,502 - Natura. Estudi, conservació i protecció de la natura ,Arqueus no cultivats ,Sediment anòxic - Abstract
The Phylum Bathyarchaeota is currently one of the most studied uncultured archaeal phyla. Bathyarchaeota are phylogenetically diverse, globally ubiquitous and especially abundant in marine subsurface sediments. Despite their global significance, their ecological role is still unknown due to the lack of cultivated representatives and the paucity of available sequenced genomes. Besides, current distribution patterns provide few clues about their metabolic capabilities and physiological requirements. The current work tackled the problem by combining different phylogenetic and molecular techniques to shed light on the main environmental drivers that affect the distribution patterns of Bathyarchaeota at a global and regional scale. Our results showed that the phylum Bathyarchaeota went across various saline–freshwater transitions during its evolution that caused diversification events that resulted in subgroups specifically adapted to marine and saline habitats. Besides, our approach provided a robust ecological framework in which Bathyarchaeota appear as a core generalist group in the sediment realm, sharing their key role with other uncultured archaeal lineages such as the Thermoplasmata. At a regional scale, a molecular survey carried out in different stratified lakes of the Banyoles Karstic System provided evidences that Bathyarchaeota are a common component of archaeal assemblages thriving in both euxinic water compartments and sediments. Multivariate analyses identified sulfide and dissolved organic carbon as main environmental variables that explain the distribution of Bathyarchaeota subgroups between the planktonic and sedimentary habitats. In the latter, Bathyarchaeota were particularly prevalent in biofilms developed on leaf litter settled in sediments of Lake Cisó, that provided a natural enrichment where to better characterize their habitat segregation, phylogenetic diversity and membrane lipid composition. The application of complementary molecular tools such as massive sequencing of 16S rRNA gene and lipidomics revealed that biofilms were almost solely composed of subgroup Bathyarchaeota-6 and possessed a characteristic, and hitherto unknown, profile of isomeric isoprenoid tetraether lipids GDGT-1, -2 and -3. Altogether, our study recognised Bathyarchaeota as key players in marine and freshwater sediments at both global and regional scales. We also identified the main environmental drivers behind their group diversification and current subgroup segregation, and stablished the co-occurrence and putative synergy between members of the Phylum Bathyarchaeota and the class Thermoplasmata. Besides, our work provides new molecular tools to better address ecological studies focused on the Bathyarchaeota and make an important step forward to finally find a specific lipid biomarker for this widespread and diverse archaeal lineage., El Fílum Bathyarchaeota és un dels llinatges d’arqueus no cultivats més estudiat degut a la seva diversitat filogenètica i ubiqüitat, especialment en sediments marins on són particularment abundants. Tot i així, la manca de representants cultivats i els pocs genomes seqüenciats del que es disposa limita el coneixement sobre el seu paper en l’ecosistema, els factors ambientals que afecten la seva distribució, les seves capacitats metabòliques i requeriments fisiològics. El treball que aquí es presenta combina tècniques moleculars i filogenètiques per conèixer quins factors ambientals són els que afecten la distribució dels Bathyarchaeota a escala global i regional. Els resultats mostren que el Fílum Bathyarchaeota ha patit, al llarg de l’evolució, diverses transicions entre ambients salins i d’aigua dolça que han resultat en una diversificació i adaptació dels diferents subgrups a cadascun d’aquests ambients. Les aproximacions moleculars que hem desenvolupat defineixen un marc ecològic robust en el que Bathyarchaeota apareix com a un grup central, generalista en termes de recursos i que desenvolupa,juntament amb altres llinatges d’arqueus no cultivats com ara els Thermoplasmata, un paper clau en els sediments. A escala regional, hem aplicat un anàlisi molecular en diversos llacs estratificats del Sistema Càrstic de Banyoles que ha permès determinar que els Bathyarchaeota són membres estables de la comunitat d’arqueus en ambients euxínics tant de la columna d’aigua com del sediment. Les anàlisi multivariants han identificat que el sulfhídric i el carboni orgànic dissolt són les principals variables ambientals que expliquen la segregació dels subgrups de batiarqueus entre nínxols planktònics i sedimentaris. Concretament en ambients bentònics, els Bathyarchaeota són particularment abundants en biofilms desenvolupats sobre fulles en descomposició acumulades al sediment del llac Cisó, representant un vertader “enriquiment natural” d’aquests arqueus. Estudis de lipidòmica i seqüenciació massiva del gen del 16S rRNA han mostrat que en aquests biofilms la comunitat d’arqueus està composada gairebé en la seva totalitat per Bathyarchaeota del subgrup–6 i mostren un perfil d’isòmers dels lípids isoprenoides de membrana (GDGT–1, –2 i –3) únic i fins ara desconegut. En conjunt, el nostre estudi identifica als Bathyarchaeota com a grup clau en sediments marins i lacustres tant a escala global com regional. També identifica els principals factors ambientals que han afectat la seva diversificació durant l’evolució així com en la segregació que actualment mostrenen ambients lacustres. També es presenten evidències de la co-ocurrència freqüent entre membres del fílum Bathyarchaeota i la classe Thermoplasmata en sediments, fet que suggereix una possible relació sintrófica entre aquests dos llinatges. El treball aporta, a més, eines moleculars que permetran estudiar els Bathyarchaeota amb més detall i avenços clau per la identificació de biomarcadors lipídics específics per aquest grup d’arqueus tan ubic i divers.
- Published
- 2017
45. Influència de miRNAs de virus sobre la susceptibilitat a esclerosi múltiple
- Author
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Blay Cadanet, Júlia, Universitat de Girona. Facultat de Ciències, Quintana Camps, Ester, and Borrego i Moré, Carles
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Multiple sclerosis -- Genetic aspects ,Esclerosi múltiple -- Aspectes genètics ,Epigenetics ,Epigenètica - Abstract
BACKGROUND: Multiple sclerosis (MS) is an autoimmune and inflammatory demyelinating disease affecting the central nervous system and the second most common cause of neurological dysfunction in young adults. It is known that the susceptibility to MS is regulated by a set of genetic, environmental and epigenetic factors, although the mechanisms by which they act remain unknown. In this study, we have investigated the relationship between one of the environmental risk factors in MS, Epstein Barr virus (EBV), which infects between 90 and 95% of the world population, and an epigenetic factor such as The microRNAs (miRNAs). The miRNAs are small molecules of non-coding RNA that participate in the regulation of gene expression at the post-transcriptional level. It is currently known that EBV has in its genome coding genes for its own miRNAs, which modify some cellular mechanisms of the host to carry out its viral cycle. OBJECTIVE: Many studies have investigated the regulatory role of miRNAs in the development of MS. The aim of this project was to relate the expression of certain EBV miRNAs to the presence of the disease. METHODS: Plasma and leukocyte buffy coat samples were collected from a total of 76 MS patients from the unitof Neurimmunology and multiple sclerosis of the Dr. Josep Trueta Hospital and from a set of patients as controls. The miRNAs were extracted with the mirVanaTM PARISTM RNA miRNA extraction kit. The miRNAs have been retrotranscribed and pre-amplified to be detected and quantified in a qRT-PCR. RESULTS: To carry out the study, eight EBV miRNAs were selected from the 44 totals. In the analysis of these 8 only one of them, the EBV-miRBART22, presented expression in 100% of buffy coat samples and in 96.96% of plasma samples. The study of differential expression of EBV-miRBART22 between control patients and MS patients showed no significant differences. The biochemical and genetic variables analyzed associated with the development of MS are more present in MS patients than in controls. The expression of EBV-miRBART22 has shown a tendency to be significant among smokers (p=0.059), where higher levels of EBV-miRBART22 (p = 0.010) were observed in women smokers. CONCLUSIONS: These results establish that EBV-miR-BART22 is overexpressed in female smokers
- Published
- 2017
46. Sulfide and methane production in anaerobic sewer pipes: from microbial community characterization to effective mitigation strategies
- Author
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Auguet Horta, Olga, Gutiérrez García-Moreno, Oriol, Borrego i Moré, Carles, Pijuan i Vilalta, Maite, and Universitat de Girona. Institut Català de Recerca de l'Aigua
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Tesis i dissertacions acadèmiques ,Sistemes col·lectors ,Sulfide ,Wastewater systems ,Sewers systems ,Sulfhídric ,Metano ,Sistemas de saneamiento ,Sulfhídrico ,504 - Ciències del medi ambient ,Biofilms ,Sistemes de sanejament ,Metà ,Sistemas colectores ,628 - Enginyeria sanitària. Aigua. Sanejament. Enginyeria de la il·luminació ,Methane - Abstract
Sewer systems transport wastewater from its source to treatment plants. During this transport, wastewater microorganisms colonize pipe walls and develop biofilms. The activity of microbial communities generates sulfide (H2S) and methane (CH4) which can cause environmental, corrosion and health problems. For that reason, a good control of H2S and CH4 emissions from sewer systems is essential for the optimal management of these facilities. Overall, the results of this PhD Thesis could be useful for sewer managers to determine the suitable strategy to control H2S and CH4 emissions in these systems. Also, this thesis provides fundamental knowledge on the microbial communities present in sewer biofilms and their role in biotransformation processes that can be highly relevant in terms of environmental and public health issues., Els tubs col·lectors s’utilitzen pel transport d’aigües residuals des del seu origen fins una estació depuradora. Durant el transport, els microorganismes que es troben en l’aigua colonitzen les superfícies interiors de les canonades del clavegueram i formen biofilms. L’activitat d’aquestes comunitats microbianes genera sulfhídric (H2S) i metà (CH4), els quals poden comportar problemes ambientals, de corrosió i salut pública. Per aquest motiu, el control acurat del H2S i CH4 en els sistemes de clavegueram és essencial per la bona gestió d’aquestes infraestructures. Els resultats d'aquesta tesi poden ser de gran utilitat per als gestors de les xarxes de clavegueram ja que permetran valorar amb dades reals quina és la millor estratègia per al control adequat de les emissions de H2S i CH4 en aquests sistemes. Aquesta tesi doctoral representa, a més, una contribució significativa pel que fa el coneixement dels grups implicats en la formació del biofilm.
- Published
- 2016
47. Diversity, dynamics and activity of Epsilonproteobacteria in a stratified karstic lake. Implications in carbon and sulfur cycles
- Author
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Noguerola Solà, Imma, Borrego i Moré, Carles, and Universitat de Girona. Institut d'Ecologia Aquàtica
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Arcobacter ,Tesis i dissertacions acadèmiques ,Lagos estratificados ,Stratified lakes ,Estany de Banyoles ,Banyoles Lake ,574 - Ecologia general i biodiversitat ,Fijación oscura de carbono inorgánico ,579 - Microbiologia ,Ecologia microbiana ,Microbial ecology ,Epsilonproteobacteria ,Fixació fosca de carboni inorgànic ,Dark inorganic carbon fixation ,Lago de Banyoles ,Llacs estratificats - Abstract
This doctoral thesis studies the abundance, diversity, seasonal dynamics and activity of Epsilonproteobacteria in a meromictic basin of Lake Banyoles during three year cycles. We applied a complementary array of molecular techniques to resolve the identity and ecological role of Epsilonproteobacteria in the system, with special focus on the contribution of these microorganisms on linking C and S cycles. Our results pointed to a clear seasonality of Epsilonproteobacteria, with maximal abundances at the redoxcline and upper monimolimnion in winter. Furthermore, results revealed the predominance of sequences affiliated to genus Arcobacter, and clearly indicated that Epsilonproteobacteria actively assimilated CO2 in the dark thus being responsible of the high rates of dark carbon fixation measured at the redoxcline in winter. Additional analyses provided additional evidence that the dominant member of the epsilonproteobacterial community is a chemolithotrophic, sulfide-oxidizing member of the genus Arcobacter, distantly related to its marine counterpart Candidatus A.sulfidicus., En aquesta tesi doctoral s’ha estudiat l’abundància, diversitat, dinàmica estacional i activitat dels Epsilonproteobacteria en una cubeta meromíctica de l’Estany de Banyoles durant tres cicles anuals. L’estudi combina diferents tècniques moleculars per resoldre la identitat i funció ecològica d’aquests microorganismes al sistema, amb especial atenció a la seva contribució als cicles del C i del S. Els resultats van mostrar una clara estacionalitat en l’abundància d’Epsilonproteobacteria amb màxims hivernals a la redoxclina i al monimolimnion, i van revelar un predomini de seqüències afiliades al gènere Arcobacter. A més, els resultats van demostrar que els Epsilonproteobacteria assimilen activament CO2 en la foscor, essent els responsables de les elevades taxes de fixació fosca de C mesurades a la redoxclina a l’hivern. Anàlisis moleculars complementàries van resoldre que el membre predominant de la comunitat estudiada és un microorganisme quimiolitotròfic i oxidador de sofre del gènere Arcobacter, filogenèticament emparentat amb l’espècie marina Candidatus A.sulfidicus.
- Published
- 2016
48. Occurrence of antibiotic resistance genes in aquatic microbial communities exposed to anthropogenic activities
- Author
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Marti Serrano, Elisabet, Balcázar, José Luis, Jofre i Torroella, Joan, Borrego i Moré, Carles, Ministerio de Ciencia e Innovación (Espanya), and Universitat de Girona. Departament de Biologia
- Subjects
Resistència als antibiòtics ,Microorganismos ,Aguas residuales ,Antibiotic resistance ,Resistencia a los antibióticos ,Microbiología acuática ,615 - Farmacologia. Terapèutica. Toxicologia. Radiologia ,Microorganisms ,ARG ,Microorganismes ,575 - Genètica general. Citogenètica general. Immunogenètica. Evolució. Filogènia ,579 - Microbiologia ,Bacteriòfags ,Aquatic microbiology ,Microbiologia aquàtica ,Aigües residuals ,Bacteriófagos ,Bacteriophages ,Fluoroquinolonas ,57 - Biologia ,Fluoroquinolones - Abstract
The overuse of antibiotics has led to the selection of resistant strains. This thesis investigated the occurrence of antibiotic resistance genes (ARGs) in aquatic microbial communities influenced by anthropogenic activities. In this study, qPCR assays were designed to quantify the plasmid-mediated quinolone resistance in environmental samples. Then, several ARGs conferring resistance to several groups of antibiotics were quantified in biofilms and sediments from a wastewater treatment plant (WWTP) discharge point and the receiving river. Ciprofloxacin-resistant strains were also isolated an screened for the presence of qnr genes and aac(6’)-Ib-cr and their association with extended-spectrum β-lactamases. A multidrug resistance-encoding plasmid from an Aeromonas sp. was further characterized. Overall, ARGs were detected in different matrices (water, biofilm and sediment), both in bacteriophages and bacteria, and different sources (rivers, effluents from several human and veterinary hospitals, subterranean water, chicken faeces and WWTP effluents), indicating that these emerging pollutants are widely distributed in the environments exposed to anthropogenic activities L'ús excessiu d'antibiòtics ha portat a la selecció de soques resistents. En aquesta tesi es va investigar l'aparició de gens de resistència als antibiòtics (ARGs) a les comunitats microbianes aquàtiques impactades per activitats antropogèniques. En primer lloc, es van dissenyar assajos de qPCR per quantificar gens de resistència a quinolones localitzats en plàsmids. A continuació, es van quantificar diversos ARGs que confereixen resistència a diversos grups d'antibiòtics en biofilms i sediments d'un punt d'abocament d'una planta de tractament d'aigües residuals (EDAR) i del riu receptor. També es van aïllar soques resistents a la ciprofloxacina i es va analitzar la presència de gens qnr i aac (6')-Ib-cr i la seva associació amb beta-lactamases d'ampli espectre. Per acabar, es va caracteritzar un plàsmid multiresistent procedent d'Aeromonas sp. En general, es van detectar ARGs en diferents matrius (aigua, biofilm i sediments), tant en bacteriòfags com a bacteris, i en diferents fonts (rius, efluents de diversos hospitals humans i veterinaris, aigües subterrànies, excrements de pollastre i efluents d'EDAR) , el que indica que aquests contaminants emergents estan àmpliament distribuïts en els ambients exposats a activitats antropogèniques This thesis was supported by the Spanish Ministry of Economy and Competitiveness (RYC-2011-08154) and the Fundación Eugenio Rodríguez Pascual, Spain
- Published
- 2014
49. Estudi dels carotenoides en espècies marrons de bacteris verds del sofre: diversitat, eco-fisiologia i regulació
- Author
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Mallorquí Fernández, Noemí, Borrego i Moré, Carles, Garcia-Gil, L. J., and Universitat de Girona. Institut d'Ecologia Aquàtica
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Tesis i dissertacions acadèmiques ,Fotosíntesis anoxigénica ,Fotosíntesi anoxigènica ,Cromatografia líquida ,Liquid chromatography ,Fisiologia bacteriana ,579 - Microbiologia ,Bacterial physiology ,Cromatografía líquida ,Fisiología bacteriana ,Anoxigenic photosynthesis - Abstract
El present treball es centra en l'estudi a diferents nivells dels carotenoides de les espècies marrons de Bacteris Verds del Sofre (GSB, de l'anglès Green Sulfur Bacteria). L'objectiu global ha estat el d'esbrinar quina és la funció d'aquests pigments dins l'aparell fotosintètic d'aquests microorganismes i aprofundir en el coneixement de la seva estructura i interaccions amb els altres pigments de l'aparell fotosintètic.En primer lloc es va dissenyar un nou mètode de cromatografia líquida d'alta resolució (HPLC) per analitzar de manera més ràpida i precisa els carotenoides de diferents soques de GSB (Capítol 3). Aquest mètode es basa en una purificació prèvia dels extractes pigmentaris amb columnes d'alúmina per eliminar les bacterioclorofil·les (BCls). Això va permetre analitzar amb una elevada resolució i en tan sols 45 min de carrera cromatogràfica els diferents carotenoides i els seus precursors, així com les configuracions trans i cis dels seus isòmers. El segon mètode utilitzat va consistir en una modificació del mètode de Borrego i Garcia-Gil (1994) i va permetre la separació precisa de tot tipus de pigments, procedents tant de cultius purs com de mostres de caràcter complex. Un exemple concret foren uns paleosediments de la zona lacustre de Banyoles. En aquests sediments (0,7-1,5 milions d'anys d'antiguitat) es van detectar, entre d'altres pigments, carotenoides específics de les espècies marrons de GSB, la qual cosa va permetre confirmar la presència d'aquests bacteris a la zona lacustre de Banyoles ja des del Pleistocè inferior. En aquest primer capítol també es van analitzar els carotenoides de Chlorobium (Chl.) phaeobacteroides CL1401 mitjançant cromatografia líquida acoblada a espectrometria de masses (LC-MS/MS), amb l'objectiu de confirmar la seva identificació i el seu pes molecular. A més, també es va avaluar l'efecte de la temperatura, la llum i diferents agents oxidants i reductors en la composició quantitativa i qualitativa dels carotenoides i les BCls d'aquesta espècie. Això va permetre confirmar el caràcter fotosensible de les BCls i que els isòmers trans/cis dels diferents carotenoides no són artefactes produïts durant la manipulació de les mostres, sinó que són constitutius de l'aparell fotosintètic d'aquests microorganismes.El Capítol 4 inclou els experiments de fisiologia duts a terme amb algunes espècies de GSB, a partir dels quals es va intentar esbrinar la dinàmica de síntesi dels diferents pigments de l'aparell fotosintètic (BCl antena, BCl a i carotenoides) durant el creixement d'aquestes espècies. Aquestes investigacions van permetre monitoritzar també els canvis en el nombre de centres de reacció (CR) durant el procés d'adaptació lumínica. La determinació experimental del nombre de CR es va realitzar a partir de la quantificació de la BCl663, l'acceptor primari en la cadena de transport d'electrons dels GSB. L'estimació del nombre de CR/clorosoma es va realitzar tant a partir de dades estequiomètriques i biomètriques presents a la bibliografia, com a partir de les dades experimentals obtingudes en el present treball. El bon ajust obtingut entre les diferents estimacions va donar solidesa al valor estequiomètric calculat, que fou, com a promig, d'uns 70 CR per clorosoma. En aquest capítol de fisiologia també es van estudiar les variacions en les relacions trans/cis pels principals carotenoides de les espècies marrons de GSB. Aquestes es van determinar a partir de cultius purs de laboratori i de poblacions naturals de GSB. Pel que fa als valors trobats en cultius de laboratori no es van observar diferències destacades entre el valor calculat a alta intensitat de llum i el calculat a baixa intensitat, essent en ambdós casos proper a 2. En els clorosomes aïllats de diferents soques marrons aquest quocient prengué un valor similar tant pels isòmers de l'isorenieratè (Isr) com pels del -isorenieratè (-Isr). En poblacions naturals de Chl. phaeobacteroides aquesta relació va ser també de 2 isòmers trans per cada isòmer cis, mantenint-se constant tant en fondària com al llarg del temps.Finalment, en el Capítol 5 es presenta un marcador molecular que permet la identificació específica d'espècies marrons de GSB. Malgrat que inicialment aquest marcador fou dissenyat a partir d'un gen implicat en la síntesi de carotenoides (crtY, el qual codifica per a una licopè ciclasa) la seqüència final a partir de la qual s'han aconseguit els encebadors selectius està relacionada amb la família de proteïnes de les Policètid-ceto-sintases (PKT). Tot i així, l'eina dissenyada pot ser de gran utilitat per a la discriminació d'espècies marrons de GSB respecte les verdes en poblacions mixtes com les que es troben en ambients naturals i obre la porta a futurs experiments d'ecologia microbiana utilitzant tècniques com la PCR en temps real, que permetria la monitorització selectiva de les poblacions d'espècies marrons de GSB en ecosistemes naturals., El presente trabajo se centra en el estudio a partir de distintos niveles de los carotenoides de las especies marrones de Bacterias Verdes del Azufre (GSB, del inglés Green Sulfur Bacteria). El objetivo global ha sido el de averiguar cual es la función de estos pigmentos en estos microorganismos así como ampliar los conocimientos de su estructura y interacciones con los otros pigmentos del aparato fotosintético.En primer lugar se diseñó un método de cromatografía líquida de alta resolución (HPLC) para analizar de forma más precisa y rápida los carotenoides de distintas cepas de GSB (Capítulo 3). Este método se caracteriza por una purificación previa de los extractos pigmentarios mediante columnas de alúmina para eliminar las bacterioclorofilas (BCls). Esto permitió analizar con una elevada resolución y en tan sólo 45 min de carrera cromatográfica los distintos carotenoides y sus precursores, así como las configuraciones trans y cis de sus isómeros. El segundo de los métodos utilizado consistió en una modificación del método de Borrego y Garcia-Gil (1994) y permitió la separación precisa de todo tipo de pigmentos, procedentes tanto de cultivos puros como de muestras de carácter complejo. Un ejemplo concreto fueron los sedimentos antiguos de la zona lacustre de Banyoles. En estos sedimentos (0,7-1,5 millones de años de antigüedad) se detectaron, entre otros pigmentos, carotenoides específicos de las especies marrones de GSB, lo que permitió confirmar la presencia de estas bacterias en la zona lacustre de Banyoles ya des del Pleistoceno inferior.En este primer capítulo también se analizaron los carotenoides de Chlorobium (Chl.) phaeobacteroides CL1401 mediante cromatografía líquida acoplada a espectrometría de masas (LC-MS/MS), con el objetivo de confirmar su identificación y su peso molecular. Además, también se analizó el efecto de la temperatura, la luz y distintos agentes oxidantes y reductores sobre la composición cuantitativa y cualitativa de los carotenoides y las BCls de esta especie. Estos experimentos permitieron confirmar el carácter fotosensible de las BCls y que los isómeros trans/cis de los distintos carotenoides no son artefactos producidos durante la manipulación de las muestras sino que son constitutivos del aparato fotosintético de estos microorganismos.El Capítulo 4 incluye los experimentos de fisiología realizados con algunas especies de GSB, centrados en elucidar los mecanismos en la dinámica de síntesis de los distintos pigmentos (BCl antena, BCl a i carotenoides) durante el crecimiento de estas especies. Estas investigaciones permitieron monitorizar también las variaciones en el número de CR durante el proceso de adaptación lumínica. A partir de la cuantificación de la BCl663, el aceptor primario en la cadena de transporte de electrones en GSB, se calculó el número de CR. La estimación de la relación CR/clorosoma se llevó a cabo, primero a partir de datos estequiométricos y biométricos presentes en la bibliografía, y luego a partir de los datos experimentales de este trabajo. El buen ajuste entre las distintas estimaciones dio solidez al valor estequiométrico calculado, el cual fue, como promedio, de unos 70 CR por clorosoma. En este capítulo de fisiología también se estudiaron las variaciones en las relaciones trans/cis entre los principales carotenoides de las especies marrones de GSB. Estas se determinaron a partir de cultivos puros de laboratorio y a partir de poblaciones naturales de GSB. Las relaciones calculadas para los cultivos no presentaron diferencias destacadas en función de las condiciones de iluminación de estos. En las dos condiciones estudiadas, alta y baja intensidad de luz, el valor de la relación trans/cis fue aproximadamente de 2. En clorosomas aislados de distintas cepas marrones de GSB la relación también fue aproximadamente de 2, tanto para el isorenierateno (Isr) como para el -isoreniearateno (-Isr). En poblaciones naturales de Chl. phaeobacteroides esta relación fue también de 2 isómeros trans por cada isómero cis, manteniéndose constante tanto en profundidad como a lo largo del tiempo. Finalmente, en el Capítulo 5 se presenta un marcador molecular que permitió la identificación específica de especies marrones de GSB. A pesar que su diseño inicial fue a partir de un gen implicado en la síntesis de carotenoides (crtY, que codifica para una licopeno ciclasa) la secuencia final a partir de la cual se han obtenido los encebadores selectivos está relacionada con la familia de proteínas de las Policétido-ceto-sintasas (PKT). A pesar de todo, la nueva herramienta puede ser de gran utilidad para la discriminación de especies marrones de GSB respecto a las verdes en poblaciones mixtas como las que se encuentran en ambientes naturales y abre las puertas a futuros experimentos de ecología microbiana utilizando técnicas como la PCR en tiempo real, que permitiría la monitorización selectiva de las poblaciones de especies marrones de GSB en ecosistemas naturales., This study is focused on the composition, distribution and function of carotenoids in the photosynthetic antenna of brown-coloured species of Green Sulfur Bacteria (GSB).The first part of the work has focused on the development of two different reverse-phase high performance liquid chromatography (HPLC) methods to study the diversity of carotenoids from different species of GSB (Chapter 3). We also introduced a pre-treatment of samples that provides a better resolution on the separation of all carotenoids including the all-trans and cis isomers, in a run time of 45 min. For complex pigment samples, such as untreated extracts or sediment pigment samples where a high diversity of pigments is suspected, we modified an existing method (Borrego and Garcia-Gil, 1994) to achieve the complete separation of all carotenoids as well as all the different bacteriochlorophylls (BChls) homologues and algal pigments. This modification was successfully applied for the detection and identification of pigments in ancient sediments (0.7-1.5 million years-old) from a quarry located in the lacustrine area of Banyoles. The detection of signature pigments for brown-coloured GSB confirmed the presence of GSB in the lacustrine area of Banyoles at least since mid-Pleistocene.In this first part we also analyzed the carotenoids from Chlorobium (Chl) phaeobacteroides CL1401 by liquid chromatography coupled to mass spectrometry (LC-MS/MS) to confirm their identification and determine their molecular mass. Besides, several experiments were done to evaluate the effect of temperature, light and different oxidising and reducing chemical agents in the quantitative and qualitative composition of carotenoids and BCls in Chl. phaeobacteroides CL1401. These results confirmed that BCls are easily photodamaged and that the all-trans and cis isomers are constitutive components of the photosynthetic apparatus of GSB and then they are not artefacts produced during sample manipulation.Chapter 4 compiles a series of experiments carried out to elucidate the dynamics of pigment synthesis during growth of several species of GSB under different light conditions. Also these investigations allowed us to monitor the changes in the number of reaction centers (RC) during the light adaptation process. The number of RC was determined from the chromatographic quantification of BChl663, the primary acceptor in the electron transport chain in GSB. The estimation of RC per chlorosome was done according to both previous pigment stoichiometries and biometric values and from the experimental data obtained in this work. An average value of 70 RC per chlorosome was obtained. This value agrees with current models of pigment composition in the photosynthetic apparatus of GSB.In this chapter the study of the evolution of trans/cis ratios for the main carotenoids in GSB during light adaptation is also included. This ratio was calculated for different strains and chlorosomes of GSB and also from natural populations of Chl. phaeobacteroides thriving in a meromictic lake. No differences were found for the trans/cis ratio between cultures grown at saturating and limiting light conditions (trans/cis ratio of 2). Furthermore, similar values were found in isolated chlorosomes of different brown-coloured strains of GSB and in natural populations. In this case the trans/cis ratio remained fairly constant throughout the water column and also along the studied growth period of the population. Finally, in Chapter 5 we present a new molecular marker for the specific detection of brown-species of GSB. Although the designed primers originally targeted a gene involved in the biosynthetic pathway of carotenoids (CrtY that encodes a lycopene cyclase), final sequence retrieved matches with a gene related to the Polyketide ketosynthases protein family. The precise function of this protein in GSB remains hitherto unknown. However, the availability of this molecular tool opens the door for future investigations on the microbial ecology of brown-coloured species of GSB using techniques as Real-time PCR to selectively monitor populations of these microorganisms in their natural habitats.
- Published
- 2003
50. Preclinical Characterization of DPI-4452: A 68 Ga/ 177 Lu Theranostic Ligand for Carbonic Anhydrase IX.
- Author
-
Massière F, Wiedemann N, Borrego I, Hoehne A, Osterkamp F, Paschke M, Zboralski D, Schumann A, Bredenbeck A, Brichory F, and Attinger A
- Subjects
- Humans, Animals, Mice, Cell Line, Tumor, Tissue Distribution, Ligands, Antigens, Neoplasm metabolism, Theranostic Nanomedicine, Precision Medicine, Female, Dogs, Carbonic Anhydrase IX metabolism, Radioisotopes therapeutic use, Gallium Radioisotopes, Lutetium
- Abstract
The membrane protein carbonic anhydrase IX (CAIX) is highly expressed in many hypoxic or von Hippel-Lindau tumor suppressor-mutated tumor types. Its restricted expression in healthy tissues makes CAIX an attractive diagnostic and therapeutic target. DPI-4452 is a CAIX-targeting cyclic peptide with a DOTA cage, allowing radionuclide chelation for theranostic purposes. Here, we report CAIX expression in multiple tumor types and provide in vitro and in vivo evaluations of
68 Ga-labeled DPI-4452 ([68 Ga]Ga-DPI-4452) and177 Lu-labeled DPI-4452 ([177 Lu]Lu-DPI-4452). Methods: CAIX expression was assessed by immunohistochemistry with a panel of tumor and healthy tissues. The molecular interactions of complexed and uncomplexed DPI-4452 with CAIX were assessed by surface plasmon resonance and cell-binding assays. In vivo characterization of radiolabeled and nonradiolabeled DPI-4452 was performed in HT-29 colorectal cancer (CRC) and SK-RC-52 clear cell renal cell carcinoma (ccRCC) human xenograft mouse models and in healthy beagle dogs. Results: Overexpression of CAIX was shown in several tumor types, including ccRCC, CRC, and pancreatic ductal adenocarcinoma. DPI-4452 specifically and selectively bound CAIX with subnanomolar affinity. In cell-binding assays, DPI-4452 displayed comparably high affinities for human and canine CAIX but a much lower affinity for murine CAIX, demonstrating that the dog is a relevant species for biodistribution studies. DPI-4452 was rapidly eliminated from the systemic circulation of beagle dogs. The highest uptake of [68 Ga]Ga-DPI-4452 and [177 Lu]Lu-DPI-4452 was observed in the small intestine and stomach, 2 organs known to express CAIX. Uptake in other organs (e.g., kidneys) was remarkably low. In HT-29 and SK-RC-52 xenograft mouse models, both [68 Ga]Ga-DPI-4452 and [177 Lu]Lu-DPI-4452 showed tumor-selective uptake; in addition, [177 Lu]Lu-DPI-4452 significantly reduced tumor growth. These results demonstrated the theranostic potential of DPI-4452. Conclusion: DPI-4452 selectively targets CAIX. [68 Ga]Ga-DPI-4452 and [177 Lu]Lu-DPI-4452 localized to tumors and were well tolerated in mice. [177 Lu]Lu-DPI-4452 demonstrated strong tumor growth inhibition in 2 xenograft mouse models. Thus, the 2 agents potentially provide a theranostic approach for selecting and treating patients with CAIX-expressing tumors such as ccRCC, CRC, and pancreatic ductal adenocarcinoma., (© 2024 by the Society of Nuclear Medicine and Molecular Imaging.)- Published
- 2024
- Full Text
- View/download PDF
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