Glycogen synthase in mantle tissue of Mytilus galloprovincialis Lamarck, 1819

Glycogen synthase (GS) from Mytilus galloprovincialis Lamarck, 1819 mantle tissue is primarily in G6P-dependent form, whose activity is four times that of the G6P-independent form. Both forms present higher activity to pH: 7, but the D-form mantains 60 % of its maximum activity at extreme pH values, whereas that of the I-form drops to 25 %. The optimum temperature is 30-35 ºC for both forms, but the I-form is more stable between 30 and 40 ºC. Kinetic data on both enzymatic forms indicate the existence of cooperative effects with regard to the substrate and effector. The I-form affinity constant for the substrate UDPG is 1.9-2.3 mM and that of the D-form is 0.9-1.3 mM. Moreover, the D-form shows an activation constant for the efector G6P of 5.2-5.6 mM.La enzima glucógeno sintasa del tejido del manto de Mytilus galloprovincialis Lamarck, 1819 se encuentra principalmente en su forma dependiente (D) de G6P, con una actividad cuatro veces mayor que la forma independiente (I) de G6P. Ambas formas presentan la mayor actividad a pH:7, pero la forma D mantiene el 60 % de su actividad a valores extremos de pH, donde la forma I disminuye la suya al 25 %. La temperatura óptima está entre 30 y 35 ºC en ambos casos, pero la forma I es más estable entre 30 y 40 ºC. Los datos cinéticos de ambas formas enzimáticas indican la existencia de efectos cooperativos respecto al sustrato y el efector. La constante de afinidad de la forma I para el sustrato UDPG es 1,9-2,3 mM y la de la D es 0,9-1,3 mM. La forma D muestra, además, una constante de activación de 5,2-5,6 mM para el efector G6P.Instituto Español de Oceanografí

Gonadal atresia during the gametogenic cycle of Mytilus galloprovincialis Lamarck, 1819 cultured in the ria of Vigo (northwest Iberian Peninsula)

During the gametogenic cycle of Mytilus, we observed atresic phenomena in gametes at different cycle stages. Gametes are degraded both within the follicle and throughout the gonoduct. This degradation shows two consecutive phases: lysis of cytoplasmatic structures and membranes, more evident in oocytes; and haemocytic digestion of lisated material. Environmental factors clearly influence this phenomenon. Atresia is intense in winter, decreases during spring, and rises again at the end of the gonadal cycle. In winter, it is related to overmaturation of gametes due to unfavourable conditions for stimulating spawning (low temperatures and lack of food availability). In summer, the high temperatures trigger the end of gametogenic cycle, and total degeneration and resorption of gonadal tissue.Durante el desarrollo gametogénico de Mytilus se han observado fenómenos de atresia de gametos en distintos momentos del ciclo. La degradación se produce en los folículos gonadales y a lo largo del gonoducto, e incluye dos etapas consecutivas: lisis de las estructuras y membranas citoplasmáticas, más evidente en ovocitos, y digestión hemocitaria del material lisado. La influencia de factores ambientales en este fenómeno es clara. La atresia es intensa en invierno, disminuye durante la primavera y vuelve a aumentar al final del ciclo gametogénico. En invierno se relaciona con la sobremaduración de gametos debida a condiciones desfavorables para el desove (bajas temperaturas y escasez de alimento). En verano, las altas temperaturas determinan la finalización del ciclo gametogénico y la degeneración y resorción total del tejido gonadal.Instituto Español de Oceanografí

Preparing the COROT space mission: new variable stars in the galactic Anticenter direction

The activities related to the preparation of the asteroseismic, photometric space mission COROT are described. Photoelectric observations, wide--field CCD photometry, uvbyB calibrations and further time--series have been obtained at different observatories and telescopes. They have been planned to complete the COROT programme in the direction of the galactic Anticenter. In addition to suitable asteroseismic targets covering the different evolutionary stages between ZAMS and TAMS, we discovered several other variable stars, both pulsating and geometrical. We compared results on the incidence of variability in the galactic Center and Anticenter directions. Physical parameters have been obtained and evolutionary tracks fitting them have been calculated. The peculiarities of some individual stars alre pointed out. Paper based on observations collected at the San Pedro Martir, Sierra Nevada, Teide, La Silla, Haute-Provence and Roque de Los Muchachos (Telescopio Nazionale Galileo and Mercator telescopes) observatories.Comment: 13 pages, 9 figures. Accepted for The Astronomical Journal (2005 May volume

Повседневность первобытного человека

Seven samples of Siluro-Devonian sedimentary rocks from the Cantabrian and Central Iberian zones of the Iberian Variscan belt have been investigated for provenance and contain four main age populations in variable relative proportion: Ediacaran–Cryogenian (c. 0.55–0.8Ga), Tonian–Stenian (0.85–1.2Ga), Palaeoproterozoic (c. 1.8–2.2Ga) and Archaean (c. 2.5–3.3Ga). Five samples contain very minor Palaeozoic (Cambrian) zircons and six samples contain minor but significant zircons of Middle and Early Mesoproterozoic (Ectasian–Calymmian, 1.6–1.8) age. These data highlight the transition from an arc environment to a stable platform following the opening of the Rheic Ocean. Variations in detrital zircon populations in Middle–Late Devonian times reflect the onset of Variscan convergence between Laurussia and Gondwana. The presence of a high proportion of zircons of Tonian–Stenian age in Devonian sedimentary rocks may be interpreted as (1) the existence of a large Tonian–Stenian arc terrane exposed in the NE African realm (in or around the Arabian–Nubian Shield), (2) the participation, from the Ordovician time, of a more easterly alongshore provenance of Tonian–Stenian zircons, and (3) an increase in the relative proportion of Tonian–Stenian zircons with respect to the Ediacaran–Cryogenian population owing to the drift of the Avalonian–Cadomian ribbon continent, or the progressive burial of Ediacaran–Cryogenian rocks coeval with the denudation of older source rocks from the craton interior

Whence come detrital zircons in Siluro-Devonian rocks from Iberia?

Seven Silurian and Devonian samples from the Cantabrian and Central Iberian zones of the Variscan belt have been investigated for paleogeographic purposes using detrital zircon U-Pb ages. A total of 764 analyses were performed. All samples contain four main age populations in variable relative proportions: Ediacaran–Cryogenian (ca. 0.55–0.8 Ga), Tonian–Stenian (0.85–1.2 Ga), Paleoproterozoic (ca. 1.8–2.2 Ga) and Archean (ca. 2.5–3.3 Ga). The two first groups constitute ca. 60–80% of the total population in all samples. In addition, 5 samples contain very minor Paleozoic (Cambrian) zircons and 6 samples contain minor but significant zircons of Middle and Early Mesoproterozoic age (Ectasian–Calymmian). These data, used in conjunction with detrital zircon U-Pb data of underlying Ordovician and Ediacaran strata constrain the evolution of the northern margin of west Gondwana, highlighting the transition from an arc environment (Cadomian-Avalonian arc orogeny) to a stable platform following the opening of the Rheic Ocean and the drift of Avalonian terranes. Variations in detrital zircon populations in Middle–Late Devonian times reflect the onset of Variscan convergence between Laurussia and Gondwana. The abundance (up to ca. 50%) of zircons of Tonian–Stenian age in Devonian sedimentary rocks, that could not have been recycled from the underlying strata, may be interpreted in different ways: a) the existence of a large Tonian–Stenian arc terrane exposed in the NE African realm (in or around the Arabian-Nubian shield) that was progressively exhumed throughout the Paleozoic, b) the participation from Ordovician times onwards of a more easterly alongshore provenance of Tonian–Stenian zircons. In this scenario, the South China block could have furnished Tonian– Stenian zircons to the Ordovician and Siluro-Devonian basins of Iberia, c) increase in the relative proportion of Tonian–Stenian zircons with respect to the Ediacaran– Cryogenian population (arc-derived zircons) due to the drift of the Avalonian-Cadomian ribbon continent following the opening of the Rheic Ocean.Peer Reviewe

Neural correlates of phonological, orthographic and semantic reading processing in dyslexia

Available online 10 August 2018Developmental dyslexia is one of the most prevalent learning disabilities, thought to be associated with dysfunction in the neural systems underlying typical reading acquisition. Neuroimaging research has shown that readers with dyslexia exhibit regional hypoactivation in left hemisphere reading nodes, relative to control counterparts. This evidence, however, comes from studies that have focused only on isolated aspects of reading. The present study aims to characterize left hemisphere regional hypoactivation in readers with dyslexia for the main processes involved in successful reading: phonological, orthographic and semantic. Forty-one participants performed a demanding reading task during MRI scanning. Results showed that readers with dyslexia exhibited hypoactivation associated with phonological processing in parietal regions; with orthographic processing in parietal regions, Broca's area, ventral occipitotemporal cortex and thalamus; and with semantic processing in angular gyrus and hippocampus. Stronger functional connectivity was observed for readers with dyslexia than for control readers 1) between the thalamus and the inferior parietal cortex/ventral occipitotemporal cortex during pseudoword reading; and, 2) between the hippocampus and the pars opercularis during word reading. These findings constitute the strongest evidence to date for the interplay between regional hypoactivation and functional connectivity in the main processes supporting reading in dyslexia.Supported by grants (RYC-2014-15440, PSI2015-65696) from the Spanish Ministry of Economy and Competitiveness (MINECO), a grant (PI2016-12) from the Basque Government and a grant (Exp. 65/15) from the Programa Red guipuzcoana de Ciencia, Tecnología e Innovación from the Diputación Foral de Gipuzkoa (P.M.P-A.); a predoctoral grant from the Department of Education, Universities and Research from the Basque Government (M.O.); grant (PSI2015-64174P) from the MINECO (F.C.); grants (PSI2015-67353-R) from the MINECO and (ERC-2011-ADG-295362) from the European Research Council (M.C.). BCBL acknowledges funding from Ayuda Centro de Excelencia Severo OchoaSEV-2015-0490 from the MINECO

Linking habitat quality with genetic diversity: a lesson from great bustards in Spain

P. 411-419The effects of habitat loss and fragmentation on the genetic structure and variability of wild populations have received wide empirical support and theoretical formalization. By contrast, the effects of habitat quality seem largely underinvestigated, partly due to technical difficulties in properly assessing habitat quality. In this study, we combine geographic information system (GIS)-based habitat-quality modelling with a landscape genetics approach based on mitochondrial DNA markers to evaluate the possible influence of habitat quality on the levels and distribution of genetic diversity in a range of natural populations (n = 15) of Otis tarda throughout Spain. Ninety-three percent of the population represented by our countrywide sample lives in good-quality habitats, while 4.5% and 2.5% occur respectively in intermediate and poor habitats. Habitat quality was highly correlated with patch size, population size and population density, indicating the reliability and predictive power of the habitat suitability model. Genetic diversity was significantly correlated with habitat quality, size and density of the population, but not with patch size. Three of a total of 20 existing matrilineages from the species’ current genetic pool are restricted to poor-quality habitats. This study therefore highlights the importance of considering both population genetics and habitat quality in a species of high conservation priority.S

Isolation of human fibroadipogenic progenitors and satellite cells from frozen muscle biopsies

Altres ajuts: Association Française contre les Myopathies (22525)Altres ajuts: Fundación Isabel GemioSkeletal muscle contains multiple cell types that work together to maintain tissue homeostasis. Among these, satellite cells (SC) and fibroadipogenic progenitors cells (FAPs) are the two main stem cell pools. Studies of these cells using animal models have shown the importance of interactions between these cells in repair of healthy muscle, and degeneration of dystrophic muscle. Due to the unavailability of fresh patient muscle biopsies, similar analysis of interactions between human FAPs and SCs is limited especially among the muscular dystrophy patients. To address this issue here we describe a method that allows the use of frozen human skeletal muscle biopsies to simultaneously isolate and grow SCs and FAPs from healthy or dystrophic patients. We show that while the purified SCs differentiate into mature myotubes, purified FAPs can differentiate into adipocytes or fibroblasts demonstrating their multipotency. We find that these FAPs can be immortalized and the immortalized FAPs (iFAPs) retain their multipotency. These approaches open the door for carrying out personalized analysis of patient FAPs and interactions with the SCs that lead to muscle loss