Homologous Recombination: To Fork and Beyond

Accurate completion of genome duplication is threatened by multiple factors that hamper the advance and stability of the replication forks. Cells need to tolerate many of these blocking lesions to timely complete DNA replication, postponing their repair for later. This process of lesion bypass during DNA damage tolerance can lead to the accumulation of single-strand DNA (ssDNA) fragments behind the fork, which have to be filled in before chromosome segregation. Homologous recombination plays essential roles both at and behind the fork, through fork protection/lesion bypass and post-replicative ssDNA filling processes, respectively. I review here our current knowledge about the recombination mechanisms that operate at and behind the fork in eukaryotes, and how these mechanisms are controlled to prevent unscheduled and toxic recombination intermediates. A unifying model to integrate these mechanisms in a dynamic, replication fork-associated process is proposed from yeast results.España Gobierno (BFU2015-63698-P

Partial depletion of histone H4 increases homologous recombination-mediated genetic instability

DNA replication can be a source of genetic instability. Given the tight connection between DNA replication and nucleosome assembly, we analyzed the effect of a partial depletion of histone H4 on genetic instability mediated by homologous recombination. A Saccharomyces cerevisiae strain was constructed in which the expression of histone H4 was driven by the regulated tet promoter. In agreement with defective nucleosome assembly, partial depletion of histone H4 led to subtle changes in plasmid superhelical density and chromatin sensitivity to micrococcal nuclease. Under these conditions, homologous recombination between ectopic DNA sequences was increased 20-fold above the wild-type levels. This hyperrecombination was not associated with either defective repair or transcription but with an accumulation of recombinogenic DNA lesions during the S and G2/M phases, as determined by an increase in the proportion of budded cells containing Rad52-yellow fluorescent protein foci. Consistently, partial depletion of histone H4 caused a delay during the S and G2/M phases. Our results suggest that histone deposition defects lead to the formation of recombinogenic DNA structures during replication that increase genomic instability.Ministerio de Ciencia y Tecnología BMC2000-0439 SAF2003-0020

Fluctuations and Instabilities of Ferromagnetic Domain Wall pairs in an External Magnetic Field

Soliton excitations and their stability in anisotropic quasi-1D ferromagnets are analyzed analytically. In the presence of an external magnetic field, the lowest lying topological excitations are shown to be either soliton-soliton or soliton-antisoliton pairs. In ferromagnetic samples of macro- or mesoscopic size, these configurations correspond to twisted or untwisted pairs of Bloch walls. It is shown that the fluctuations around these configurations are governed by the same set of operators. The soliton-antisoliton pair has exactly one unstable mode and thus represents a critical nucleus for thermally activated magnetization reversal in effectively one-dimensional systems. The soliton-soliton pair is stable for small external fields but becomes unstable for large magnetic fields. From the detailed expression of this instability threshold and an analysis of nonlocal demagnetizing effects it is shown that the relative chirality of domain walls can be detected experimentally in thin ferromagnetic films. The static properties of the present model are equivalent to those of a nonlinear sigma-model with anisotropies. In the limit of large hard-axis anisotropy the model reduces to a double sine-Gordon model.Comment: 15 pages RevTex 3.0 (twocolumn), 9 figures available on request, to appear in Phys Rev B, Dec (1994

Estudo dos parametros de secagem e construção de um secador de baixo custo para files salgados de pescado

Orientador : Kil Jin ParkDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia AgricolaMestradoMaquinas AgricolasMestre em Engenharia Agrícol

Micro y nanoestructuras de óxido de estaño y sus nanocompuestos con óxido de grafeno: síntesis, luminiscencia y aplicaciones en energía

Debido a que el SnO2 presenta unas interesantes propiedades fsico-qumicas, este material ha sido ampliamente empleado en diversas aplicaciones, entre las cuales destaca el sensado de gases, su uso como electrodos transparentes, en catalisis y aplicaciones relacionadas con el almacenamiento de energía. No obstante, dichas aplicaciones pueden mejorarse mediante el control de determinados parametros tales como como la morfología, el tamaño, la introduccion de dopantes y la fabricacion de materiales compuestos basados en grafeno, lo que ha motivado la novedosa investigacion llevada a cabo en esta Tesis Doctoral. A lo largo de esta memoria de Tesis Doctoral se exponen y discuten los resultados de mayor relevancia relativos a la síntesis de nanopartículas de SnO2 dopadas con Li, as como al crecimiento de microestructuras alargadas de SnO2 dopado con Li. Por otro lado, tambien se han sintetizado materiales compuestos de estas nanopartculas con una matriz de oxido de grafeno (GO). Ademas, se ha estudiado su posible aplicacion como materiales luminiscentes y se han realizado pruebas de concepto para su uso en celdas electroqumicas de ion-Li (LIB's) para el almacenamiento de energía..

Sustainability, Investment Strategy, and Governance: Evaluation of Wind Energy Sector in North-West Spain

[Abstract]: Climate change is one of the greatest challenges humanity faces globally. For this reason, governmental efforts to reduce emissions of polluting gases have multiplied in the last decade. Against this panorama, petroleum companies have adopted a strategic policy focused on energy diversification, intending to contribute to sustainable development. In the case of Spain, wind energy has been one of the renewable energies that have attracted the most investment from petroleum companies. In particular, this trend is especially acute in Galicia (a region located in the northwest of Spain), since its biophysical conditions and, above all, its institutional framework for the promotion of photovoltaic energy has aroused the interest of petroleum companies. The objective of this article is to perform a feasibility análisis of an average wind project in Galicia. through the calculation of the initial investment, the necessary financing, and the preparation of balance sheets and profit and loss accounts. For this purpose, the methodology used is based on the preparation of a feasibility plan, through which the necessary investment is analyzed and the flows of receipts and payments generated by the company are considered. In this way, this analysis is intended to be useful for companies that are considering the appropriateness/inappropriateness to carry out this type of investment. The results show a high internal rate of return, which indicates the high profitability of the project.Xunta de Galicia; ED431C2018/48Xunta de Galicia; ED431E2018/07This research has been funded by the Conseller ıa de Cultura, Educaci on e Ordenaci on Universitaria of the Xunta de Galicia in Spain the postdoctoral grant ED481B2018/095 and the following grants: ED431C2018/48 and ED431E2018/07. In addition, this publication is part of the Spanish R&D&I project RTI2018-099225-B-I00, funded by MCIN/AEI/10.13039/501100011033/and FEDER ‘A way of doing Europe’. The authors are also grateful for the valuable contributions made by Juan Carlos López Rodríguez.España; FEDER ‘A way of doing Europe’España; MCIN/AEI/10.13039%2F501100011033

Parallel use of CID, HCD and ETD for characterization of proteic allergens found in pollensomes

Comunicaciones a congreso

Los graduados sociales en el mundo empresarial: Un análisis descriptivo de opiniones sobre su formación desde el ámbito universitario y profesional

De todos es conocida la polémica que viene existiendo, desde hace tiempo, acerca del distanciamiento que se observa, entre la formación académica ofrecida por la gran mayoría de carreras universitarias, y la posterior práctica profesional a la que los universitarios han de enfrentarse. Al hilo de lo anterior, el objetivo del presente trabajo, no ha sido otro que el de llevar a cabo un estudio comparativo en base a una serie de sondeos de opinión, realizados sobre distintas muestras poblacionales, todas ellas relacionadas o vinculadas, de alguna forma, con la formación y práctica profesional de la figura del Graduado Social. Del contraste de estos resultados con la información contenida en los planes de estudio que rigen la formación de los Graduados Sociales, tanto el actualmente vigente como el proyecto pendiente de aprobación, podremos obtener información para reforzar o rebatir la vieja idea sobre la falta de respuesta del ámbito académico a los requerimientos del mercado laboral, en nuestro caso, dentro del campo profesional de los Graduados Sociales

Crosstalk between chromatin structure, cohesin activity and transcription

Background: A complex interplay between chromatin and topological machineries is critical for genome architec‑ ture and function. However, little is known about these reciprocal interactions, even for cohesin, despite its multiple roles in DNA metabolism. Results: We have used genome‑wide analyses to address how cohesins and chromatin structure impact each other in yeast. Cohesin inactivation in scc1‑73 mutants during the S and G2 phases causes specific changes in chromatin structure that preferentially take place at promoters; these changes include a significant increase in the occupancy of the − 1 and + 1 nucleosomes. In addition, cohesins play a major role in transcription regulation that is associated with specific promoter chromatin architecture. In scc1‑73 cells, downregulated genes are enriched in promoters with short or no nucleosome‑free region (NFR) and a fragile “nucleosome − 1/RSC complex” particle. These results, together with a preferential increase in the occupancy of nucleosome − 1 of these genes, suggest that cohesins promote transcription activation by helping RSC to form the NFR. In sharp contrast, the scc1‑73 upregulated genes are enriched in promoters with an “open” chromatin structure and are mostly at cohesin‑enriched regions, suggesting that a local accumulation of cohesins might help to inhibit transcription. On the other hand, a dramatic loss of chromatin integrity by histone depletion during DNA replication has a moderate effect on the accumulation and distribution of cohesin peaks along the genome. Conclusions: Our analyses of the interplay between chromatin integrity and cohesin activity suggest that cohesins play a major role in transcription regulation, which is associated with specific chromatin architecture and cohesin‑ mediated nucleosome alterations of the regulated promoters. In contrast, chromatin integrity plays only a minor role in the binding and distribution of cohesins.Spanish Ministry of Economy and Competitivenes BFU2012-38171, BFU2015-63698-PAndalusian Government P12-CTS-227