Energy conversion in Purple Bacteria Photosynthesis

The study of how photosynthetic organisms convert light offers insight not only into nature's evolutionary process, but may also give clues as to how best to design and manipulate artificial photosynthetic systems -- and also how far we can drive natural photosynthetic systems beyond normal operating conditions, so that they can harvest energy for us under otherwise extreme conditions. In addition to its interest from a basic scientific perspective, therefore, the goal to develop a deep quantitative understanding of photosynthesis offers the potential payoff of enhancing our current arsenal of alternative energy sources for the future. In the following Chapter, we consider the trade-off between dynamics, structure and function of light harvesting membranes in Rps. Photometricum purple bacteria, as a model to highlight the priorities that arise when photosynthetic organisms adapt to deal with the ever-changing natural environment conditions.Comment: Chapter, to appear in Photosynthesis 2011, INTEC

Light-harvesting in bacteria exploits a critical interplay between transport and trapping dynamics

Light-harvesting bacteria Rhodospirillum Photometricum were recently found to adopt strikingly different architectures depending on illumination conditions. We present analytic and numerical calculations which explain this observation by quantifying a dynamical interplay between excitation transfer kinetics and reaction center cycling. High light-intensity membranes (HLIM) exploit dissipation as a photo-protective mechanism, thereby safeguarding a steady supply of chemical energy, while low light-intensity membranes (LLIM) efficiently process unused illumination intensity by channelling it to open reaction centers. More generally, our analysis elucidates and quantifies the trade-offs in natural network design for solar energy conversion.Comment: 4 pages and 4 figures. Accepted for publication in Physical Review Letters

Phylogeny and synonymy of Gyrodinium heterostriatum comb. nov. (Dinophyceae), a common unarmored dinoflagellate in the world oceans

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Gómez, F., Artigas, L.F., Gast, R.J. Phylogeny and synonymy of Gyrodinium heterostriatum comb. nov. (Dinophyceae), a common unarmored dinoflagellate in the world oceans. Acta Protozoologica, 59 (2), (2020): 77-87, doi: 10.4467/16890027AP.20.007.12675.The North Sea and the English Channel are regions with a long tradition of plankton studies, where the colony-forming haptophyte Phaeocystis globosa dominates the spring phytoplankton blooms. Among its predators, we investigated an abundant unarmored dinoflagellate (~3000 cells per liter) in the North Sea in May 2019. It has been reported in the literature as Gymnodinium heterostriatum or G. striatissimum, and often identified as Gyrodinium spirale. Phylogenetic analyses using the small-, large subunit- and Internal Transcriber Spacers of the ribosomal RNA (SSU-, LSU-, ITS rRNA) gene sequences indicate that our isolates clustered within the Gyrodinium clade. The new sequences formed a sister group with sequences of the freshwater taxon Gyrodinium helveticum, being one of the infrequent marine-freshwater transitions in the microbial world. This isolate is the first characterized member of a clade of numerous environmental sequences widely distributed from cold to tropical seas. This common and abundant taxon has received several names due to its morphological plasticity (changes of size and shape, often deformed after engulfing prey) and the difficulty in discerning surface striation. We conclude that the priority is for the species name Gymnodinium heterostriatum Kofoid & Swezy 1921, a new name that was proposed for Gymnodinium spirale var. obtusum sensu Dogiel 1906. The species Gyrodinium striatissimum (Hulburt 1957) Gert Hansen & Moestrup 2000 and Gymnodinium lucidum D. Ballantine in Parke & Dixon 1964 (=G. hyalinum M. Lebour 1925) are posterior synonyms. We propose Gyrodinium heterostriatum comb. nov. for Gymnodinium heterostriatum.F.G. was partly supported by the convention #2101893310 between CNRS INSU and the French Ministry of Ecology (MTES) for the implementation of the Monitoring Program of the European Marine Strategy Framework directive (MSFD) for pelagic habitats and the descriptor ‘biodiversity’. Samples were collected within the framework of JERICO-NEXT (www.jerico-ri.eu), a European (H2020) project to establish a joint international network of coastal observatories, during a 4-day collaborative monitoring campaign of the Southern North Sea. Part of the infrastructure and data were provided by VLIZ (Flanders Marine Institute) and funded by Research Foundation-Flanders (FWO) as part of the Belgian contribution to the LifeWatch project

Fabricación histórica de ladrillos refractarios en Valdemorillo, Madrid: Minas y fábricas de D. Ángel González

Desde el catastro del Marqués de la Ensenada (1752-1753) hasta nuestros días hay datos sobre la existencia de tejares y alfares en Valdemorillo. La existencia al SE del municipio de un alargado afloramiento del Utrillas, rico en caolines, hizo que se instalaran en su término, a partir de 1845, fábricas de loza y de ladrillo refractario. Nosotros hemos estudiado una de estas instalaciones, se trata de las minas subterráneas y hornos de D. ÁNGEL GONZÁLEZ, que aún se conservan en relativo buen estado, constituyendo un Patrimonio Arqueológico Industrial de interés. Los estudios se han realizado en el marco de un proyecto de investigación de la Consejería de Educación de la Comunidad de Madrid, titulado: "Arqueología Industrial: Conservación del patrimonio minero-metalúrgico madrileño (II)"

Base de datos informatizada en Proyectos de Patrimonio Minero-Metalúrgico. Aplicaciones al caso de Madrid

El proyecto "CONSERVACiÓN DEL PATRIMONIO MINERO Y METALÚRGICO MADRILEÑO-U", segunda fase del iniciado bajo el título "ARQUEOLOGíA INDUSTRIAL: CONSERVACIÓN DEL PATROMINIO MINEROMETALÚRGICO MADRILEÑO", forma parte de la Convocatoria de Proyectos de Investigación en Humanidades y Ciencias Sociales de la Comunidad Autónoma de Madrid. En el primer estudio se pretendía abordar la evaluación, clasificación y catalogación de aquellos elementos, relacionados con el ámbito minero y metalúrgico, que estuvieran vinculados a la Comunidad Autónoma de Madrid

Retos de la formación médica de grado

Las Facultades de Medicina españolas han iniciado un nuevo proceso de reforma curricular en el marco de la implantación del Espacio Europeo de Educación Superior (EEES). Este proceso constituye, sin duda, una nueva oportunidad, quizás la última en mucho tiempo, para llevar a cabo de una vez por todas la reforma en profundidad que nuestra formación de grado requiere. Los retos que se nos plantean son muchos y nada fáciles de afrontar. En este artículo vamos a discutir cuáles son estos retos y cómo deberíamos alcanzarlos. Para saber hacia dónde hemos de ir es imprescindible saber de dónde partimos y sobre todo dónde estamos. Por ello dividiremos nuestra exposición en tres períodos: el primero, que engloba el siglo XX desde 1930 a 1990, es un período en el que a pesar de su dilatada extensión apenas se producen cambios substanciales en nuestra formación de grado; el segundo, que se extiende desde finales del siglo XX a los principios del siglo actual (concretamente desde 1990 al 2003), abarca nuestro presente actual; y el tercero a partir del 2004, en el que comienzan a surgir los retos que el futuro nos depara

Temperature and pressure constraints near the freezing point

The isothermal-isobaric ensemble molecular-dynamics method MD(T,p,N) proposed by Nosé and Hoover is used to study the fluctuations in a two-dimensional Lennard-Jones fluid, close to the freezing point. The T and p constraints in this method do not affect the dynamical behavior of the system, since spontaneous fluctuations in the density allow the system to freeze and melt just as do the T and p fluctuations in the microcanonical ensemble MD(E,V,N) close to the melting zone