19,19'-diacyloxy signature: an atypical level of structural evolution in carotenoid pigments.

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Detección e caracterización de pigmentos fotosintéticos en fitoplancto mariño

Fractions of nano- and picoplankton are important components of the phytoplankton in the oceans. These organisms, like the rest of the marine phototrophs, present a complex set of photosynthetic pigments (chlorophylls, carotenoids and phycobilins) that, selectively distributed in different taxa of eukaryotes and bacteria, play a physiological role which reaches a global importance. The determination of pigments in oceanic waters has to face several difficulties, resulting in analytical needs repeatedly emphasized: (1) the description of the marine ecosystem need large number of samples; (2) the samples may contain variety of species with pigment endowments of great complexity which complicate their analysis (3) in extensive oceanic áreas photosynthetic organisms occur in very low cell densities, compromising pigment detection with the currently available techniques and (4) many pigments of high biological significance are difficult to ascertain due to analytical interferences with structurally similar ones. The need for the best techniques to describe populations of the phytoplankton of oligotrophic ecosystems and the knowledge of the analytical possibilities of new techniques lead us to propose the following objectives: 1. To develop methodologies for the preconcentration of pigment extracts, aimed at increasing the sensitivity of the analysis. 2. Design new chromatographic methods with innovative selectivities, able to discriminate a greater number of pigments and, therefore, increase the capacity of classification and distinction among taxonomic entities in phytoplankton populations. 3. Obtain rapid chromatographic systems, with analytical times in all cases less than 15 minutes. 4. Characterization the structures of new chlorophylls and carotenoids (chemotaxonomic biomarkers) mainly of picoplankton species. 5. Study, using all the methodologies previously designed, the pigment distribution of populations of phytoplankton in the South of the Mediterranean Sea.Las fracciones de nano- y picoplancton son importantes componentes del fitoplancton en los océanos. Estos organismos, como el resto de los fotoautótrofos marinos, presentan un conjunto complejo de pigmentos fotosintéticos (clorofilas, carotenoides, y ficobilinas) que juegan un papel fisiológico que alcanza una importancia global. La determinación de pigmentos en aguas oceánicas debe afrontar varias dificultades, que se traducen en diferentes necesidades: (1) La descripción de los ecosistemas marinos necesita gran número de muestras; (2) las muestras pueden contener gran variedad de especies con dotaciones pigmentarias de gran complejidad que compliquen su análisis (3) en extensas regiones oceánicas los organismos fotosintéticos se presentan en densidades celulares muy bajas, comprometiendo la detección de sus pigmentos con las técnicas actualmente disponibles y (4) muchos pigmentos de gran significación biológica son difíciles de determinar debido a que son estructuralmente semejantes. La necesidad de disponer de las mejores técnicas para describir las poblaciones de fitoplancton de ecosistemas oligotróficos (5) y el conocimiento de las posibilidades analíticas de nuevas técnicas nos llevan a proponer los siguientes objetivos: 1. Desarrollar metodologías de preconcentración de los extractos pigmentarios encaminadas a incrementar la sensibilidad de los análisis. 2. Diseñar nuevos métodos cromatográficos con selectividades innovadoras, y así aumentar la capacidad de clasificación y distinción entre entidades taxonómicas. 3. Obtener sistemas cromatográficos veloces, con tiempos de análisis en cualquier caso inferiores a 15 minutos. 4. Caracterizar las estructuras de nuevas clorofilas y carotenoides, marcadores de grupos taxonómicos de fitoplancton, principalmente de especies de picoplancton marino. 5. Estudiar, empleando todas las metodologías antes diseñadas, la distribución pigmentaria de poblaciones de fitoplancton en el Sur del mar Mediterráneo.As fraccións de nano- e picoplancto son importantes compoñentes do fitoplancto nos océanos. Estes organismos, como no resto dos fotoautótrofos mariños, presentan un conxunto complexo de pigmentos fotosintéticos (clorofilas, carotenoides e ficobilinas) que xogan un papel fisiológico que alcanza unha importancia global. A determinación de pigmentos en augas oceánicas debe afrontar varias dificultades, que se traducen en diferentes necesidades: (1) A descrición dos ecosistemas mariños necesita gran número de mostras; (2) as mostras poden conter gran variedade de especies con dotación pigmentarias de gran complexidade que compliquen a súa análise (3) en extensas rexións oceánicas os organismos fotosintéticos preséntanse en densidades celulares moi baixas, comprometendo a detección dos seus pigmentos coas técnicas actualmente dispoñibles e (4) moitos pigmentos de gran significación biolóxica son difíciles de determinar debido a que son estructuralmente semellantes. A necesidade de dispor das mellores técnicas para describir as poboacións do fitoplancto de ecosistemas oligotróficos (5) e o coñecemento das posibilidades analíticas de novas técnicas lévannos a propor os seguintes obxetivos: 1. Desenrolar metodoloxías de preconcentración dos extractos pigmentarios encamiñadas a incrementar a sensibilidade dos análises. 2. Deseñar novos métodos cromatográficos con selectividades innovadoras, e así aumentar a capacidade de clasificación e distinción entre entidades taxonómicas. 3. Obter sistemas cromatográficos veloces, con tempos de análise en calquera caso inferiores a 15 minutos. 4. Caracterizar as estruturas de novas clorofilas e carotenoides, marcadores de grupos taxonómicos de fitoplancto, principalmente de especies de picoplanto mariño. 5. Estudar, empregando tódalas metodoloxías antes deseñadas, a distribución pigmentaria de poboacións de fitoplancto no Sur do mar Mediterráneo.Ministerio de Economía y Competitividad de España. Proyecto OLIGOPIGMENTS | Ref. CTM2012-32181Ministerio de Economía y Competitividad de España. Proyecto i-Small | Ref. CTM2014-56119-RMinisterio de Economía y Competitividad de España | Ref. BES-2013-06575

Data from: Predictions of response to temperature are contingent on model choice and data quality

The equations used to account for the temperature dependence of biological processes, including growth and metabolic rates are the foundations of our predictions of how global biogeochemistry and biogeography change in response to global climate change. We review and test the use of 12 equations used to model the temperature dependence of biological processes across the full range of their temperature response, including supra- and sub-optimal temperatures. We focus on fitting these equations to thermal response curves for phytoplankton growth, but also tested the equations on a variety of traits across a wide diversity of organisms. We found that many of the surveyed equations have comparable abilities to fit data and equally high requirements for data quality (number of test temperatures and range of response captured), but lead to different estimates of cardinal temperatures and of the biological rates at these temperatures. When these rate estimates are used for biogeographic predictions, differences between the estimates of even the best fitting models can exceed the global biological change predicted for a decade of global warming. As a result, studies of the biological response to global changes in temperature must make careful consideration of model selection and of the quality of the data used for parametrizing these models

Temperature response

Data and analysis scripts in R. Data from published sources not included

Potential of the Red Alga Dixoniella grisea for the Production of Additives for Lubricants

There is an increasing interest in algae-based raw materials for medical, cosmetic or nutraceutical applications. Additionally, the high diversity of physicochemical properties of the different algal metabolites proposes these substances from microalgae as possible additives in the chemical industry. Among the wide range of natural products from red microalgae, research has mainly focused on extracellular polymers for additive use, while this study also considers the cellular components. The aim of the present study is to analytically characterize the extra- and intracellular molecular composition from the red microalga Dixoniella grisea and to evaluate its potential for being used in the tribological industry. D. grisea samples, fractionated into extracellular polymers (EPS), cells and medium, were examined for their molecular composition. This alga produces a highly viscous polymer, mainly composed of polysaccharides and proteins, being secreted into the culture medium. The EPS and biomass significantly differed in their molecular composition, indicating that they might be used for different bio-additive products. We also show that polysaccharides and proteins were the major chemical compounds in EPS, whereas the content of lipids depended on the separation protocol and the resulting product. Still, they did not represent a major group and were thus classified as a potential valuable side-product. Lyophilized algal fractions obtained from D. grisea were found to be not toxic when EPS were not included. Upon implementation of EPS as a commercial product, further assessment on the environmental toxicity to enchytraeids and other soil organisms is required. Our results provide a possible direction for developing a process to gain an environmentally friendly bio-additive for application in the tribological industry based on a biorefinery approach