CDK2 regulates nuclear envelope protein dynamics and telomere attachment in mouse meiotic prophase

In most organisms, telomeres attach to the nuclear envelope at the onset of meiosis to promote the crucial processes of pairing, recombination and synapsis during prophase I. This attachment of meiotic telomeres is mediated by the specific distribution of several nuclear envelope components that interact with the attachment plates of the synaptonemal complex. We have determined by immunofluorescence and electron microscopy that the ablation of the kinase CDK2 alters the nuclear envelope in mouse spermatocytes, and that the proteins SUN1, KASH5 (also known as CCDC155) and lamin C2 show an abnormal cap-like distribution facing the centrosome. Strikingly, some telomeres are not attached to the nuclear envelope but remain at the nuclear interior where they are associated with SUN1 and with nuclear-envelope-detached vesicles. We also demonstrate that mouse testis CDK2 phosphorylates SUN1 in vitro. We propose that during mammalian prophase I the kinase CDK2 is a key factor governing the structure of the nuclear envelope and the telomere-led chromosome movements essential for homolog pairin

Study of the prolificacy in the segureña sheep. Preliminary results

The prolificacy of the Segureña sheep breed as a expresión of its potential numerical productivity is under study in the last years because this trait is considered as a selection criteria as the weight and daily gains. We have analizad more that 207850 parturitions. The results obatined here are expresed as a function of the number of parturition of each ewe and the month of parturition, showing mean values around 1.30 lambs by parturition, very interesting taking into account the conditions of exterme hardness in extensive systems where the breed is exploited.La prolificidad de la raza Segureña como expresión de la productividad numérica potencial que atesora la población está siendo estudiada en los últimos años pues este parámetro podría considerarse como un posible criterio de selección al igual que las variables de pesos y crecimientos. Se analizan más de 207850 partos. Los resultados obtenidos se expresan en función del número de parto de la hembra y mes de parto, obteniéndose valores medios en torno a 1,30 corderos por parto cifra interesante teniendo en cuenta las condiciones de extrema dureza en extensivo en las que se produce esta raza

Structural basis of meiotic telomere attachment to the nuclear envelope by MAJIN-TERB2-TERB1.

Meiotic chromosomes undergo rapid prophase movements, which are thought to facilitate the formation of inter-homologue recombination intermediates that underlie synapsis, crossing over and segregation. The meiotic telomere complex (MAJIN, TERB1, TERB2) tethers telomere ends to the nuclear envelope and transmits cytoskeletal forces via the LINC complex to drive these rapid movements. Here, we report the molecular architecture of the meiotic telomere complex through the crystal structure of MAJIN-TERB2, together with light and X-ray scattering studies of wider complexes. The MAJIN-TERB2 2:2 hetero-tetramer binds strongly to DNA and is tethered through long flexible linkers to the inner nuclear membrane and two TRF1-binding 1:1 TERB2-TERB1 complexes. Our complementary structured illumination microscopy studies and biochemical findings reveal a telomere attachment mechanism in which MAJIN-TERB2-TERB1 recruits telomere-bound TRF1, which is then displaced during pachytene, allowing MAJIN-TERB2-TERB1 to bind telomeric DNA and form a mature attachment plate

Experimental results and modelling of humidity control strategies for greenhouses in continental and coastal settings in the Mediterranean region. II: Modelling of strategies

Strategies for humidity control —with and without heating— were evaluated via simulations performed with apreviously developed model (see accompanying paper, this issue, part I). With heating, the best strategy combined theuse of a humidity setpoint with step control of the roof window, increasing the ventilation in line with the outsidetemperature. Without heating, the best strategy again combined the use of a humidity setpoint with step control of theroof window, but required ventilation to be increased in line with the inside air temperatur

Modification of cellulose based membranes by ␥-radiation: Effect of cellulose content

Abstract Electrochemical characterization of three cellophane membranes with different content of regenerated cellulose was carried out by determining salt diffusion and ion transport numbers, which were obtained from diffusion and membrane potential measurements carried out with the membranes in contact with NaCl solutions at different concentrations. Results show a decrease for salt permeability with the increase of cellulose content in the membranes, which can be related with the decrease in the swelling degree of the samples containing higher amount of cellulose, while a slightly increase in the cation transport number was obtained. The effect of ␥-irradiation in structural and electrochemical parameters of these membranes was also studied. Two different radiation doses (10 J/kg and 80 J/kg) were used, which were delivered by a 60 Co Cobalt Unit. Changes in membrane permeability, cation and water transport numbers were obtained in order to determine structural and electrical modifications in the membrane matrix as a result of irradiation. According to the experimental results, ␥-radiation produces: (i) a reduction in salt permeability, which strongly depends on the membrane cellulose content (between 20% and 40% for 10 J/kg dose), but much lower reduction exist when the two different radiation doses for a given sample are compared; (ii) a slight increase in the negative character of cellophane membranes independently of the cellulose content

(I)Migrantes, diversidades e desigualdades no sistema educativo português : balanço e perspectivas

O objectivo do presente artigo consiste em procurar transmitir um olhar sociologicamente informado no que concerne à situação portuguesa no domínio das políticas educativas públicas e investigações produzidas relacionadas com o sistema educativo e a (i)migração, ou seja, com a tentativa de construção de uma educação intercultural. Neste sentido, será realizada uma análise descritiva e compreensivo-interpretativa da evolução desta problemática em Portugal desde que a mesma se tornou objecto de reflexão por parte de investigadores/as e políticos nos finais da década de oitenta, início da década de noventa do século XX. Nesta análise, será dada ênfase às investigações e quadros teóricos produzidos e às medidas legislativas e políticas educativas no domínio do tratamento da diferença cultural dentro do sistema educativo português.The aim of this article consists in attempting to transmit a sociologically informed view in what the Portuguese situation in the field of public policies and research related to the educational system and (im)migration are concerned, that is, in attempting to construct an intercultural education. In this way, a descriptive and comprehensiveinterpretative analysis of the evolution of this problem in Portugal will be realized, since the latter became an object of reflection on the part of researchers and politicians towards the end of the 80s, the beginning of the 90s of the XXth century. In this analysis, emphasis will be given on the research and theoretical frameworks produced and on the legislative measures and educational policies in the field of treating cultural difference in the Portuguese educational system

Selection indices to identify drought-tolerant grain sorghum cultivars.

Twenty-five cultivars of grain sorghum [Sorghum bicolor (L.) Moench] were examined under both drought stress and normal conditions in 4 experiments. In each condition, genotypes were evaluated in a factorial experiment using a randomized complete block design with 3 replications. Eight drought tolerance indices including stability tolerance index, mean productivity (MP), geometric MP, harmonic mean, stress susceptibility index, tolerance index, yield index, and yield stability index were estimated for each genotype based on grain yield under drought (Ys) and irrigated conditions (Yp). The results indicated that there were positive and significant correlations among Yp and Ys with geometric MP, MP, harmonic mean, and stability tolerance index, indicating that these factors are better predictors of Yp and Ys than tolerance index, stress susceptibility index, yield stability index, and yield index. Based on adjusted means at Yp and Ys, indices geometric MP, MP, harmonic mean, and stability tolerance index, unweighted pair group method with arithmetic mean cluster and biplot analysis, the most tolerant cultivars were ?9929020?, ?9929034?, and ?N 95B?

Estudio del equilibrio y cinética de adsorción de Cd(II), Ni(II) y Cr(VI) usando Quitosano y Quitosano modificado con cobre

In this paper, the equilibrium and adsorption kinetics of Cr(VI), Cd(II) and Ni(II) onto Chitosan and Cu-chitosan was studied. Metal ion solutions at different initial concentration were put in contact with chitosan and Cu-chitosan and the mixture was agitated by 3 – 4 h. Afterwards, the samples were analyzed by atomic absorption spectroscopy. The experimental data of adsorption equilibrium were evaluated by application of Langmuir and Freundlich isotherms; while the kinetics experimental data were evaluated using kinetic models of pseudo-first order and pseudo-second order. The results showed that the metallic ions were effectively adsorbed by the chitosan (Cd and Ni) and Cu-chitosan (Cr). Besides, it was found that the experimental data of adsorption equilibrium of Cr(VI) and Ni(II) fit the Langmuir model, while the equilibrium adsorption data of Cd(II) were better fitted by Freundlich model. The maximum adsorption capacity of chromium (29.7 mg/g Cu-chitosan), cadmium (102.0 mg/g chitosan) and nickel (83.31 mg/g chitosan) was determined using the Langmuir model. The results of adsorption kinetics of the metallic ions showed that the experimental data were better adjusted by pseudo-second order model. Therefore, the rate-limiting step is the adsorption reaction and not mass transfer processes. DOI: http://dx.doi.org/10.5377/nexo.v26i2.1285 Nexo Revista Científica Vol. 26, No. 02, pp. 56-68/Diciembre 2013En este trabajo, se estudió el equilibrio y la cinética de adsorción de Cd(II), Ni(II) en quitosano y Cr(VI) en quitosano modificado con cobre. Para ello, soluciones de iones metálicos a diferentes concentraciones, fueron puestas en contacto con el adsorbente y se agitaron por un período de 3 – 4 h. Al final del proceso, las muestras fueron analizadas en un espectrómetro de absorción atómica. Los datos experimentales del equilibrio de adsorción de los iones metálicos fueron evaluados aplicando las isotermas de Langmuir y Freundlich; mientras los datos cinéticos fueron evaluados utilizando los modelos cinéticos de pseudo-primer orden y pseudo-segundo orden. Los resultados del  proceso demostraron que los iones fueron eficazmente adsorbidos por el quitosano (Cd y Ni) y por el Cu-quitosano (Cr). Además, se comprobó que los datos experimentales del equilibrio de adsorción de Cr(VI) y Ni(II) se ajustan al modelo de Langmuir; mientras que los datos experimentales del Cd(II) fueron mejor ajustados por el modelo de Freundlich. Mediante el uso de la isoterma de Langmuir se determinó la capacidad máxima de adsorción de cromo (29.7 mg/g Cu-quitosano), cadmio (102.0 mg/g quitosano) y níquel (83.31 mg/g quitosano). Los resultados de la cinética de adsorción de los iones metálicos mostraron que los datos experimentales fueron mejor ajustados por el modelo de pseudo-segundo orden; es decir, el paso limitante en la velocidad es la reacción de adsorción y no la transferencia de masa. DOI: http://dx.doi.org/10.5377/nexo.v26i2.1285 Nexo Revista Científica Vol. 26, No. 02, pp. 56-68/Diciembre 201

Global genetic diversity of var2csa in Plasmodium falciparum with implications for malaria in pregnancy and vaccine development

Malaria infection during pregnancy, caused by the sequestering of Plasmodium falciparum parasites in the placenta, leads to high infant mortality and maternal morbidity. The parasite-placenta adherence mechanism is mediated by the VAR2CSA protein, a target for natural occurring immunity. Currently, vaccine development is based on its ID1-DBL2Xb domain however little is known about the global genetic diversity of the encoding var2csa gene, which could influence vaccine efficacy. In a comprehensive analysis of the var2csa gene in >2,000 P. falciparum field isolates across 23 countries, we found that var2csa is duplicated in high prevalence (>25%), African and Oceanian populations harbour a much higher diversity than other regions, and that insertions/deletions are abundant leading to an underestimation of the diversity of the locus. Further, ID1-DBL2Xb haplotypes associated with adverse birth outcomes are present globally, and African-specific haplotypes exist, which should be incorporated into vaccine design

Influence of the feedstock characteristics on the microstructure and properties of Al2O3 TiO2 plasma-sprayed coatings

[EN] Atmospheric plasma spraying (APS) is an interesting technique to obtain nanostructured coatings due to its versatility, simplicity and relatively low cost. However, nanometric powders cannot be fed into the plume using conventional feeding systems, due to their low mass and poor flowability, and must be adequately reconstituted into sprayable micrometric agglomerates. In this work, Al2O3–13 wt.%TiO2 nanostructured and submicron-nanostructured powders were deposited using APS. The feedstocks were obtained by spray drying from two starting suspensions, prepared by mixing two commercial nanosuspensions of Al2O3 and TiO2, or by adding nanosized TiO2 and submicron-sized Al2O3 powders to water. The spray-dried granules were heat-treated to reduce their porosity and the resultant powders were fully characterized. Optimization of the deposition conditions enabled the reconstituted powders to be successfully deposited, yielding coatings that were well bonded to the substrate. The coating microstructure, characterized by SEM, was formed by semi-molten feedstock agglomerates surrounded by fully molten particles that act as a binder. Moreover, microhardness, adhesion, and tribological behavior were determined, and the impact of the granule characteristics on these properties was studied. It was found that changing the feedstock characteristics allowed controlling the coating quality and properties.This work has been supported by the Spanish Ministry of Science and Innovation (project MAT2009-14144-C03).Vicent, M.; Bannier, E.; Benavente Martínez, R.; Salvador Moya, MD.; Molina, T.; Moreno, R.; Sánchez, E. (2013). Influence of the feedstock characteristics on the microstructure and properties of Al2O3 TiO2 plasma-sprayed coatings. Surface and Coatings Technology. 220:74-79. https://doi.org/10.1016/j.surfcoat.2012.09.042S747922