Characterization of TrxC, an Atypical Thioredoxin Exclusively Present in Cyanobacteria

Cyanobacteria form a diverse group of oxygenic photosynthetic prokaryotes considered to be the antecessor of plant chloroplast. They contain four different thioredoxins isoforms, three of them corresponding to m, x and y type present in plant chloroplast, while the fourth one (named TrxC) is exclusively found in cyanobacteria. TrxC has a modified active site (WCGLC) instead of the canonical (WCGPC) present in most thioredoxins. We have purified it and assayed its activity but surprisingly TrxC lacked all the classical activities, such as insulin precipitation or activation of the fructose-1,6-bisphosphatase. Mutants lacking trxC or over-expressing it were generated in the model cyanobacterium Synechocystis sp. PCC 6803 and their phenotypes have been analyzed. The ΔtrxC mutant grew at similar rates to WT in all conditions tested although it showed an increased carotenoid content especially under low carbon conditions. Overexpression strains showed reduced growth under the same conditions and accumulated lower amounts of carotenoids. They also showed lower oxygen evolution rates at high light but higher Fv’/Fm’ and Non-photochemical-quenching (NPQ) in dark adapted cells, suggesting a more oxidized plastoquinone pool. All these data suggest that TrxC might have a role in regulating photosynthetic adaptation to low carbon and/or high light conditions.España, MINECO BIO2016-75634-PJunta de Andalucía P12-BIO-1119 , BIO-28

La ciencia y nosotros

Science is the most refined cultural element to describe and manage the environment. It is the result of a permanent evolutionary algorithm and represents an adaptive biological advantage for the human species. Science evolves socially through physical records and information media, whose changes influence both science and society. Information professionals have been managing these physical records or knowledge containers. The technodigital revolution grows an industrialized information society where science is a productive workforce, with a neurodigital nature, and develops as a collective enterprise. Science containers are now very changeable, plural, segmented, networking, and take on a business look: they become “specific information platforms”. Information professionals’ position is rather weak, but they have the possibility to turn into information engineers, to participate in some of those platforms and to compete individually as information managers in the science arena

Application of Semi-Empirical Ventilation Models in A Mediterranean Greenhouse with Opposing Thermal and Wind Effects. Use of Non-Constant Cd (Pressure Drop Coefficient Through the Vents) and Cw (Wind Effect Coefficient)

The present work analyses the natural ventilation of a multi-span greenhouse with one roof vent and two side vents by means of sonic anemometry. Opening the roof vent to windward, one side vent to leeward, and the other side vents to windward (this last vent obstructed by another greenhouse), causes opposing thermal GT (m3 s−1) and wind effects Gw (m3 s−1), as outside air entering the greenhouse through the roof vent circulates downward, contrary to natural convection due to the thermal effect. In our case, the ventilation rate RM (h−1) in a naturally ventilated greenhouse fits a second order polynomial with wind velocity uo (RM = 0.37 uo2 + 0.03 uo + 0.75; R2 = 0.99). The opposing wind and thermal effects mean that ventilation models based on Bernoulli’s equation must be modified in order to add or subtract their effects accordingly—Model 1, in which the flow is driven by the sum of two independent pressure fields GM1=√(∣∣G2T±G2w∣∣) , or Model 2, in which the flow is driven by the sum of two independent fluxes GM2=|GT±Gw| . A linear relationship has been obtained, which allows us to estimate the discharge coefficient of the side vents (CdVS) and roof vent (CdWR) as a function of uo [CdVS = 0.028 uo + 0.028 (R2 = 0.92); CdWR = 0.036 uo + 0.040 (R2 = 0.96)]. The wind effect coefficient Cw was determined by applying models M1 and M2 proved not to remain constant for the different experiments, but varied according to the ratio uo/∆Tio0.5 or δ [CwM1 = exp(−2.693 + 1.160/δ) (R2 = 0.94); CwM2 = exp(−2.128 + 1.264/δ) (R2 = 0.98)]

Testing quaternion properness: generalized likelihood ratios and locally most powerful invariants

This paper considers the problem of determining whether a quaternion random vector is proper or not, which is an important problem because the structure of the optimal linear processing depends on the specific kind of properness. In particular, we focus on the Gaussian case and consider the two main kinds of quaternion properness, which yields three different binary hypothesis testing problems. The testing problems are solved by means of the generalized likelihood ratio tests (GLRTs) and the locally most powerful invariant tests (LMPITs), which can be derived even without requiring an explicit expression for the maximal invariant statistics. Some simulation examples illustrate the performance of the proposed tests, which allows us to conclude that, for moderate sample sizes, it is advisable to use the LMPITs.This work was supported by the Spanish Government, Ministerio de Ciencia e Innovación (MICINN), under projects COSIMA (TEC2010-19545-C04-03) and COMONSENS (CSD2008-00010, CONSOLIDERINGENIO 2010 Program)

The book as exception

The traditional book, which is losing its central position as a paradigmatic record of information and knowledge, is a “cultural exception” within the communication environment of the human species. Although vanishing as a norm, as a standard, the book undertakes new tasks and assumes the role of a symbol, even an ethnographic value

Academia and collective science

The organization of science is based on scientific communication media. New technologies in information and knowledge systems, such as cyber-infrastructures, grid platforms, or academic social web, tend towards something like a collective scientific intelligence, a complex sociotechnical system that goes against, and perhaps will replace, some basic institutions and rules of classical academic science

Chemical Abstracts celebrates one hundred years

A review of the first hundred years of Chemical Abstracts Service (CAS) reviews its significance and role as: (i) a witness to the changes in international scientific leadership; (ii) a classical example of scientific documentation; (iii) a general catalogue of chemical molecules in our natural and artificial world; (iv) a close ally of chemical and pharmacological industries; and (v) a paradoxically unsettled agent at a crossroads of the digital world. The uncertain future of CAS also symbolizes the uncertainty that reigns in scientific communication nowadays

Science and us

Science is the most refined cultural element to describe and manage the environment. It is the result of a permanent evolutionary algorithm and represents an adaptive biological advantage for the human species. Science evolves socially through physical records and information media, whose changes influence both science and society. Information professionals have been managing these physical records or knowledge containers. The technodigital revolution grows an industrialized information society where science is a productive workforce, with a neurodigital nature, and develops as a collective enterprise. Science containers are now very changeable, plural, segmented, networking, and take on a business look: they become “specific information platforms”. Information professionals’ position is rather weak, but they have the possibility to turn into information engineers, to participate in some of those platforms and to compete individually as information managers in the science arena