Bovine in vitro Embryo Production: State of the Art

In the last 10 years, bovine in vitro embryo production has shown significant progress on a global level, partly driven by a better understanding of technology potential in the livestock sector. Importantly, in 2016, the number of viable bovine embryos produced in vitro exceeded the number of transferable embryos derived in vivo (multiple ovulation embryo transfer, MOET). In vitro embryo production (PIVE) requires the correct formulation of culture media to allow the development of oocytes and embryos. In cattle, the PIVE process includes three sequential processes in vitro: maturation of oocytes, fertilization of matured oocytes, and culture of fertilized oocytes to obtain embryo development of blastocyst. In vitro-produced blastocysts can be transferred fresh to synchronized recipients or be cryopreserved (vitrified or frozen) for later transfer or commercialization. These assisted reproduction techniques have demonstrated acceptable outcomes in livestock, helping technicians and farmers to improve reproductive performance, production efficiency, and genetic progress. Keywords: bovine, in vitro, embryo, reproduction, technology. RESUMEN En los últimos 10 años, la producción de embriones bovinos in vitro ha mostrado un progreso significativo a escala mundial, en parte impulsado por una mejor comprensión del potencial de esta tecnología en el sector ganadero. Es importante destacar que en 2016, el número de embriones bovinos viables producidos in vitro superó al número de embriones transferibles producidos in vivo (transferencia de embriones de ovulación múltiple, MOET). La producción in vitro de embriones (PIVE) requiere la formulación correcta de medios de cultivo que permitan el desarrollo de ovocitos y embriones. En bovinos, el proceso de PIVE incluye tres procesos secuenciales in vitro: la maduración de ovocitos, la fecundación de los ovocitos madurados y el cultivo de cigotos hasta alcanzar el desarrollo embrionario de blastocisto. Los blastocistos producidos in vitro pueden ser transferidos en fresco a receptoras sincronizadas o pueden ser criopreservados (vitrificados o congelados) para su posterior transferencia o comercialización. Estas técnicas de reproducción asistida han sido probadas con éxito en el campo comercial, ayudando a técnicos y productores de ganado bovino a mejorar el desempeño reproductivo, la eficiencia productiva y la mejora genética. Palabras Clave: bovino, in vitro, embrión, reproducción, tecnología

Markbooks

A collection of carefully left traces — and their occasionally accompanying thoughts — Markbooks is the result of “an ongoing conversation about attention, its ecologies, its forms, and the markings of its passage.” “For many of the authors included here, the practice of making — and then reading — their little book located them in time… [T]here is paper, and there are pencils, and there are bodies to mark their own motion.

Conformational changes during pore formation by the perforin-related protein pleurotolysin

Membrane attack complex/perforin-like (MACPF) proteins comprise the largest superfamily of pore-forming proteins, playing crucial roles in immunity and pathogenesis. Soluble monomers assemble into large transmembrane pores via conformational transitions that remain to be structurally and mechanistically characterised. Here we present an 11 Å resolution cryo-electron microscopy (cryo-EM) structure of the two-part, fungal toxin Pleurotolysin (Ply), together with crystal structures of both components (the lipid binding PlyA protein and the pore-forming MACPF component PlyB). These data reveal a 13-fold pore 80 Å in diameter and 100 Å in height, with each subunit comprised of a PlyB molecule atop a membrane bound dimer of PlyA. The resolution of the EM map, together with biophysical and computational experiments, allowed confident assignment of subdomains in a MACPF pore assembly. The major conformational changes in PlyB are a ~70° opening of the bent and distorted central β-sheet of the MACPF domain, accompanied by extrusion and refolding of two α-helical regions into transmembrane β-hairpins (TMH1 and TMH2). We determined the structures of three different disulphide bond-trapped prepore intermediates. Analysis of these data by molecular modelling and flexible fitting allows us to generate a potential trajectory of β-sheet unbending. The results suggest that MACPF conformational change is triggered through disruption of the interface between a conserved helix-turn-helix motif and the top of TMH2. Following their release we propose that the transmembrane regions assemble into β-hairpins via top down zippering of backbone hydrogen bonds to form the membrane-inserted β-barrel. The intermediate structures of the MACPF domain during refolding into the β-barrel pore establish a structural paradigm for the transition from soluble monomer to pore, which may be conserved across the whole superfamily. The TMH2 region is critical for the release of both TMH clusters, suggesting why this region is targeted by endogenous inhibitors of MACPF function

A Tale of Two Type Ia Supernovae: The Fast-declining Siblings SNe 2015bo and 1997cn

We present optical and near-infrared photometric and spectroscopic observations of the fast-declining Type Ia supernova (SN) 2015bo. SN 2015bo is underluminous (MB = −17.50 ± 0.15 mag) and has a fast-evolving light curve (Δm15(B) = 1.91 ± 0.01 mag and sBV = 0.48 ± 0.01). It has a unique morphology in the observed V − r color curve, where it is bluer than all other supernovae (SNe) in the comparison sample. A 56Ni mass of 0.17 ± 0.03 M⊙ was derived from the peak bolometric luminosity, which is consistent with its location on the luminosity–width relation. Spectroscopically, SN 2015bo is a cool SN in the Branch classification scheme. The velocity evolution measured from spectral features is consistent with 1991bg-like SNe. SN 2015bo has a SN twin (similar spectra) and sibling (same host galaxy), SN 1997cn. Distance moduli of μ = 34.33 ± 0.01 (stat) ±0.11 (sys) mag and μ = 34.34 ± 0.04 (stat) ± 0.12 (sys) mag are derived for SN 2015bo and SN 1997cn, respectively. These distances are consistent at the 0.06σ level with each other, and they are also consistent with distances derived using surface-brightness fluctuations and redshift-corrected cosmology. This suggests that fast-declining SNe could be accurate distance indicators, which should not be excluded from future cosmological analyses

Pedidos y transporte: Una unidad estratégica de estudio en indicadores logísticos de la nueva era

The purpose of this research is to analyze the main trends that comprise orders and transportation. For this, three sources of analysis have been considered as reference: 1) Field Research, in the commercial sector of zone 3 of Ecuador. 2) Graphic descriptive analysis of the market 3) Statistical inferential analysis using the Friedman test. The methodology was framed in an explanatory descriptive analysis, the research instrument was a survey applied to a sample made up of 373 commercial companies. The results obtained reflected an asymptotic significance level of 0.092 using the Friedman test for the variables considered compared to the critical level of 0.05, which indicates that there are no significant statistical differences between the companies in relation to the dimensions of orders and transportation. in the 4 selected provinces.La presente investigación tiene como objetivo analizar las tendencias principales que comprende los pedidos y el transporte, para ello se ha considerado como referencia tres fuentes de análisis: 1) Investigación de Campo, en el sector comercial de la zona 3 del Ecuador. 2) Análisis gráfico descriptivo del mercado 3) Análisis estadístico inferencial mediante la prueba de Friedman. La metodología se enmarcó en un análisis descriptivo explicativo, el instrumento de investigación fue una encuesta aplicado a una muestra conformada de 373 empresas comerciales. Los resultados obtenidos reflejaron un nivel de significancia asintótica de 0.092 mediante la prueba de Friedman para las variables consideradas en comparación con el nivel crítico de 0.05 por lo cual se indica que no hay diferencias estadísticas significativas entre las empresas en relación a las dimensiones pedidos y transporte en las 4 provincias seleccionadas.

Constructivismo web: un enfoque en crecimiento para el desarrollo de la logística integral

This research deals with the evolution of digital information of commercial and integral logistics, the objective was to review what is the best catalog for searches and trends and the behavior of scientific production over the years, through WEB tools : catalog: Scielo, Scopus and Redalyc, in addition, the trends were reviewed through googletrends, an analysis of academic documents with publish or perish software. The results determined that the best catalog for searches in English and Spanish of the integral logistics is Redalyc since it provides in Spanish under the keyword: Integral Logistics with a total of 133,245 results and 19,834 resultsin English under the keyword: Integrated Logistic, from the year 1999 to 2017.Esta pesquisa trata da evolução da informação digital de logística comercial e integral, com o objetivo de revisar qual o melhor catálogo de buscas e tendências e o comportamento da produção científica ao longo dos anos, através de ferramentas WEB.: catálogo: Scielo, Scopus e Redalyc, além disso, as tendências foram revisadas através de googletrends, uma análise de documentos acadêmicos com o software publish or perish. Os resultados determinaram que o melhor catálogo para pesquisas em inglês e espanhol da logística integral é Redalyc, uma vez que fornece em espanhol sob a palavra-chave: Integral Logistics com um total de 133.245 resultados e 19.834 resultados em Inglês sob a palavra-chave: Integrated Logistic, de o ano de 1999 a 2017.La presente investigación trata sobre la evolución de la información digital de la logística comercial e integral, el objetivo fue revisar cual es el mejor catalogo para búsquedas y las tendencias y el comportamiento de la producción científica a través de los años, a través de herramientas WEB: catálogo: Scielo, Scopus y Redalyc, además se revisó las tendencias a través de googletrends, un análisis de documentos académicos con el software publish or perish. Los resultados determinaron que el mejor catalogó para búsquedas en inglés y español de la logística integral es Redalyc ya que aporta en español bajo la palabra clave: Logística Integral con un total de 133.245 resultados y 19.834 resultados en ingles bajo el keyword: Integrated Logistic, desde el año 1999 al 2017