The expression patterns of genes involved in the RNAi pathways are tissue-dependent and differ in the germ and somatic cells of mouse testis

6 páginas, 3 figuras, 2 tablas -- PAGS nros. 306-311Different RNA interference (RNAi) components participate in post-transcriptional regulation via RNA silencing. The expression pattern of the genes Drosha and Dicer and the members of the Argonaute family Ago1, Ago2, Ago3 and Ago4, all elements participating in the RNAi pathways, were investigated in mouse somatic tissues and testis using quantitative RT-PCR. Expression patterns of different testis cells and those emerging during testis development were also investigated. The differential patterns of expression seen suggest potential pleiotropic roles for certain components of the RNAi machinery. Both spermatocytes and spermatids showed a defined gene expression pattern. The strong expression of Ago4 in germ cells suggests that this protein plays a key role in germ-cell differentiation in the seminiferous epitheliumThis work was supported by grants from the MEC (BFU2004-03977/BFI) and the MSC (FIS PI071007)Peer reviewe

Gene silencing by RNAi in mouse Sertoli cells

<p>Abstract</p> <p>Background</p> <p>RNA interference (RNAi) is a valuable tool in the investigation of gene function. The purpose of this study was to examine the availability, target cell types and efficiency of RNAi in the mouse seminiferous epithelium.</p> <p>Methods</p> <p>The experimental model was based on transgenic mice expressing EGFP (enhanced green fluorescent protein). RNAi was induced by in vivo transfection of plasmid vectors encoding for short hairpin RNAs (shRNAs) targeting EGFP. shRNAs were transfected in vivo by microinjection into the seminiferous tubules via the rete testis followed by square wave electroporation. As a transfection reporter, expression of red fluorescent protein (HcRed 1) was used. Cell types, the efficiency of both transfections and RNAi were all evaluated.</p> <p>Results</p> <p>Sertoli cells were the main transfected cells. A reduction of about 40% in the level of EGFP protein was detected in cells successfully transfected both in vivo and in vitro. However, the efficiency of in vivo transfection was low.</p> <p>Conclusion</p> <p>In adult seminiferous epithelial cells, in vivo post-transcriptional gene silencing mediated by RNAi via shRNA is efficient in Sertoli cells. Similar levels of RNAi were detected both in vivo and in vitro. This also indicates that Sertoli cells have the necessary silencing machinery to repress the expression of endogenous genes via RNAi.</p

Waste-to-energy options within a circular economy strategy in a developing country: the case of the bio bio region in Chile

In Chile, during the last 40 years the municipal solid waste (MSW) generation rate has shown a 4-fold increase due to population growth, fast urbanization and improved material standards. As in most developing countries, this trend is expected to continue as economic policies foster greater industrial investment and increases in domestic consumption. Currently, MSW are landfilled near ever expanding urban areas, leading to growing public concerns, and prompting new control legislation. Up-to-date MSW management practises are being promoted in order to maximise waste valorisation, including recycling, and waste-to-energy, within a circular economy strategy. However, new resource consumption, waste streams, air emissions and effluents may arise when changing from a linear to a circular economy model. Therefore, environmental performance of alternative scenarios must take into consideration the complete life cycle to avoid problem shifting. Within this context, this paper presents a case study of three alternative waste-to energy scenarios, as part of a circular economy strategy, involving combustion, gasification, and landfill biogas, at the BioBio Region in Southern Chile. This is an industrial region housing over 2 million inhabitants and generating more than one million tonnes of MSW per year. The study assesses waste-to energy alternatives considering an integrated waste management life cycle approach. Boundaries include waste collection, transport, pre-treatment processes, by-products generation, and heat/power production. MSW transport, recycling rates, chemical compositions, and calorific values, were obtained from primary sources, whereas energy conversion efficiencies and other data gaps were estimated from the Ecoinvent database. Results provide a complete view of the environmental performance of each alternative scenario, including potential climate change effects and other environmental impacts, and also the positive contributions of material and energy recovery. This work illustrates the value of life cycle assessment in the context of decision making concerning circular economy scenarios

Dynamical properties of liquid Al near melting. An orbital-free molecular dynamics study

The static and dynamic structure of liquid Al is studied using the orbital free ab-initio molecular dynamics method. Two thermodynamic states along the coexistence line are considered, namely T = 943 K and 1323 K for which X-ray and neutron scattering data are available. A new kinetic energy functional, which fulfills a number of physically relevant conditions is employed, along with a local first principles pseudopotential. In addition to a comparison with experiment, we also compare our ab-initio results with those obtained from conventional molecular dynamics simulations using effective interionic pair potentials derived from second order pseudopotential perturbation theory.Comment: 15 pages, 12 figures, 2 tables, submitted to PR

SCIENTIFIC COUNCIL MEETING – 20 - 24 SEPTEMBER 2021

Report of the Scientific Council meeting held by WebEx from 20 to 24 September 2021Versión del editor

Density fluctuations and single-particle dynamics in liquid lithium

The single-particle and collective dynamical properties of liquid lithium have been evaluated at several thermodynamic states near the triple point. This is performed within the framework of mode-coupling theory, using a self-consistent scheme which, starting from the known static structure of the liquid, allows the theoretical calculation of several dynamical properties. Special attention is devoted to several aspects of the single-particle dynamics, which are discussed as a function of the thermodynamic state. The results are compared with those of Molecular Dynamics simulations and other theoretical approaches.Comment: 31 pages (in preprint format), 14 figures. Submitted to Phys. Rev.

Formation of Mass Transport Deposits on the Submarine Bank of Portimão (Gulf of Cadiz, SW Iberia)

European Geosciences Union General Assembly (2017. Viena)The development of submarine mass transport deposits (MTDs) plays an important geo-hazards role along continental margins. Accordingly, their identification and characterization is crucial to understand their sources, dynamics, frequency and spatial distribution. In this work a piston core located at the slope (2876 m water depth) of the southern flank of Portimao Bank (Portugal, Gulf of Cadiz, SW Iberia) underwent detailed magnetic (fabric and rock magnetism) and sedimentological (grain-size, carbonates, organic matter) analyses complemented by AMS 14C dating. Such multidisciplinary study identified about one meter of sediments that is unconformable with the ages obtained above and below this layer. Its magnetic fabric, as determined by anisotropy of magnetic susceptibility, indicates sharply changes from oblate to neutral shape, decrease of the anisotropy and preferred orientation of the magnetic susceptibility ellipsoid. Such layer is also individualized by sedimentary parameters, especially in its upper part by a lighter colour and decrease of the mean grain size than the rest of the core. Based on these results it is possible to conclude that the sedimentary column analyzed here shows evidence of an on-going development of a slide, which is well individualized and characterized by magnetic fabric studies.Instituto Dom Luiz, University of Lisbon, PortugalInstituto Superior de Engenharia de Lisboa, PortugalEstrutura de Missão para a Extensão da Plataforma Continental, PortugalInstituto Português do Mar e da Atmosfera, PortugalInstituto de Ciencias del Mar, Consejo Superior de Investigaciones Científicas, EspañaCentro Oceanográfico de Málaga, Instituto Español de Oceanografía, EspañaInstituto Geológico y Minero de España, Españ