Transdifferentiation from cornea to lens in Xenopus laevis depends on BMP signalling and involves upregulation of Wnt signalling

<p>Abstract</p> <p>Background</p> <p>Surgical removal of the lens from larval <it>Xenopus laevis </it>results in a rapid transdifferention of central corneal cells to form a new lens. The trigger for this process is understood to be an induction event arising from the unprecedented exposure of the cornea to the vitreous humour that occurs following lens removal. The molecular identity of this trigger is unknown.</p> <p>Results</p> <p>Here, we have used a functional transgenic approach to show that BMP signalling is required for lens regeneration and a microarray approach to identify genes that are upregulated specifically during this process. Analysis of the array data strongly implicates Wnt signalling and the Pitx family of transcription factors in the process of cornea to lens transdifferentiation. Our analysis also captured several genes associated with congenital cataract in humans. Pluripotency genes, in contrast, were not upregulated, supporting the idea that corneal cells transdifferentiate without returning to a stem cell state. Several genes from the array were expressed in the forming lens during embryogenesis. One of these, <it>Nipsnap1</it>, is a known direct target of BMP signalling.</p> <p>Conclusions</p> <p>Our results strongly implicate the developmental Wnt and BMP signalling pathways in the process of cornea to lens transdifferentiation (CLT) in <it>Xenopus</it>, and suggest direct transdifferentiation between these two anterior eye tissues.</p

An amphibian with ambition: a new role for Xenopus in the 21st century

Much of our knowledge about the mechanisms of vertebrate early development comes from studies using Xenopus laevis. The recent development of a remarkably efficient method for generating transgenic embryos is now allowing study of late development and organogenesis in Xenopus embryos. Possibilities are also emerging for genomic studies using the closely related diploid frog Xenopus tropicalis

Are there functional consequences of a reduction in selenium intake in UK subjects?

Dietary Se levels in the UK have fallen over the last 20 years and recent surveys indicate that average Se intakes are 30-40 microg/d, which is well below the current UK reference nutrient intake for adult men (75 microg/d) or women (60 microg/d). Functional consequences of this decline have not been recognised, although epidemiological data suggest it may contribute to increased risk of infections and incidence of some cancers. Previous data have indicated that biochemical changes in Se-dependent proteins occur in otherwise healthy UK subjects given small Se supplements. The current studies have focused on the effect of small Se supplements on the immune response since there is evidence of specific interactions between Se intake and viral replication, and since the potential anti-cancer effects of Se may be mediated by non-antioxidant effects of Se such as changes in immune function. Data indicate that subjects given small Se supplements (50 or 100 microg Se/d) have changes in the activity of Se-dependent enzymes and evidence of improved immune function and clearance of an administered live attenuated virus in the form of poliovirus vaccine. Responses of individual subjects to Se supplements are variable, and current work is evaluating potential explanations for this variability, including genetic variability and pre-existing Se status

Hur ett certifieringsorgan kan bidra till en hållbar värdekedja

Med miljöföroreningar och överfisket i världshaven står fiskbranschen inför stora utmaningar för att ställa om till ett mer hållbart fiske. Landbaserade system för fisk- och skaldjursproduktion är en relativt ny produktionsform som uppkommit där systemen har en uppbyggnad likt ett kretslopp. Systemen är effektiva, hållbara och har en minimal negativ påverkan på miljön. Fiskbranschen är en relativt oreglerad bransch med bristande riktlinjer och lagar jämfört med andra animalieproduktioner både i Sverige och globalt. Därför utvecklar Svenskt Sigill en IPstandard för landbaserad fisk- och skaldjursproduktion som ger producenter möjlighet att kunna certifiera sig och märka sina produkter med Svenskt Sigill. Detta kommer skapa riktlinjer, ett ordentligt regelverk och ge konsumenter ett hållbart alternativ av fiskkonsumtion. I och med denna nya certifiering kommer många aktörer bli inblandade. Hur Svenskt Sigill förhåller sig till de andra aktörerna i denna utveckling intresserade uppsatsförfattarna. En miljömärkning på en produkt skapar ett mervärde hos konsumenterna som ökar betalningsviljan på produkten. Detta mervärde utvecklas i varje del av en värdekedja som består av flera aktörer. Syftet med denna studie är då att utveckla och förstå rollen av certifierande organ i utvecklingen av mer hållbara värdekedjor. För att kunna besvara frågeställningarna i denna kvalitativa fallstudie har representanter från Svenskt Sigill, Axfood, Coop och ICA intervjuats. Svenskt Sigill är ett certifierande organ som kontrollerar och utvecklar standarder inom livsmedel och blommor. Axfood, Coop och ICA är aktörer inom dagligvaruhandeln som tillsammans har marknadsandelar motsvarande ca 90 %. För att uppnå syftet har en teoretisk syntes gjorts som kopplar hållbar utveckling med företagsekonomiska teorier kring värdekedja och marknadskanaler. Resultatet visar att Svenskt Sigill har fått förfrågningar att göra en certifiering av landbaserade system för fisk- och skaldjur, från både producenter och handeln. Detta betyder att fallstudien inte visar sig överensstämma med den traditionella modellen av marknadskanaler. Istället visade sig marknadskanalen ha en mer dynamisk utformning där det sker ett samspel mellan aktörerna. Att ha ett certifierande organ likt Svenskt Sigill i en värdekedja gör att den blir mer dynamisk och frångår sin traditionella linjära form. De verkar som en kontrollerande tredje part samtidigt som de sammankopplar handeln med producenter och till viss del konsumenter.With environmental pollution and overfishing in the oceans, the fish industry faces major challenges to convert to a more sustainable fishing. Land-based systems are a relatively new form of production that arose where the systems have a structure similar to a cycle. The systems are efficient, durable and have a minimal negative impact on the environment. The fish industry is a relatively unregulated industry with a lack of guidelines and laws compared to another animal production both in Sweden and globally. Therefore, Svenskt Sigill develops an IP-standard for land-based fish and shellfish production, which gives producers the opportunity to certify themselves and label their products with Svenskt Sigill. This will create guidelines, a proper regulatory framework and give consumers a sustainable alternative of fish consumption. With this new certification, many actors will be involved. The essay writers are interested in how the Svenskt Sigill relates to the other actors in this development. An eco-label on a product creates added value for consumers, which increases the willingness to pay for the product. This added value develops in every part of a value chain that consists of several actors. The purpose of this study is to develop and understand the role of certifying organizations in the development of more sustainable value chains. In order to answer the questions in this qualitative case study, representatives from the Svenskt Sigill, Axfood, Coop and ICA have been interviewed. Svenskt Sigill is a certification bodies that controls and develops standards in food and flowers. Axfood, Coop and ICA are actors in the grocery trade, which together have market shares corresponding to about 90 %. In order to achieve the purpose, a theoretical synthesis has been made that links sustainable development with business-economic theories on value chain and market channels. The result shows that the Svenskt Sigill has received requests to make a certification of land-based systems for seafood, from both producers and the trade. This means that the case study does not prove to be consistent with the traditional model of market channels. Instead, the market channel turned out to have a more dynamic design where there is an interaction between the actors. Having a certifying body like the Svenskt Sigill in a value chain makes it more dynamic and departs from its traditional linear form. They act as a controlling third party while linking trade with producers and to some consumers

Prácticas educativas de educación ambiental enfocadas en la temática del agua

El objetivo de esta investigación fue investigar cómo las prácticas educativas de Educación Ambiental (EA) enfocadas en el tema del agua están siendo abordadas en la investigación en la Biblioteca Digital Brasileña de Tesis y Disertaciones (BDTD) sin demarcación de período, utilizando el descriptor: “Educación Ambiental”, constituyendo una investigación con enfoque cualitativo. Por tanto, se realizó una nueva búsqueda utilizando el descriptor: “Agua” en cada una de las encuestas seleccionadas, con la intención de encontrar prácticas educativas de EA con enfoque en el agua. Los cuales fueron analizados a partir de las perspectivas de EA crítica y EA transformadora/emancipadora de Loureiro (2003, 2006, 2020). Como resultado, obtuvimos 10 disertaciones, con prácticas variadas, desde juegos hasta excursiones. En cuanto a las perspectivas, se encontró un predominio en la perspectiva crítica, que está estrechamente ligada al uso de juegos y cuestionarios, siendo las principales prácticas encontradas en las investigaciones. De esta forma, pudimos comprender las prácticas educativas de la EA con sus respectivas perspectivas. Por tanto, entendemos que el rol de los educadores en el espacio escolar es fundamental, como mediador del conocimiento, para brindar de manera crítica transformaciones individuales y colectivas, junto con la emancipación del individuo a favor de la problemática ambiental.O objetivo desta pesquisa, foi investigar como as práticas educativas de Educação Ambiental (EA) com foco na temática da água estão sendo abordadas em pesquisas na Biblioteca Digital Brasileira de Teses e Dissertações (BDTD) sem demarcação de período, usando-se o descritor: “Educação Ambiental”, constituindo-se em uma pesquisa de abordagem qualitativa. Por conseguinte, foi feita uma nova busca usando-se o descritor:“Água” em cada uma das pesquisas selecionadas, na intenção de encontrar práticas educativas de EA com foco na água. As quais foram analisadas com base nas perspectivas de EA crítica e de EA transformadora/emancipatória de Loureiro (2003, 2006, 2020). Comoresultado, obtivemos 10 dissertações, com práticas variadas, desde jogos até saídas de campo. Quanto as perspectivas, foi encontrado predominância na perspectiva crítica, a qual, está intimamente ligada ao uso de jogos e de questionário, sendo as principais práticas encontradas nas pesquisas. Dessa maneira, conseguimos compreender as práticas educativas de EA com as respectivas perspectivas. Logo, entendemos ser fundamental, a função dos educadores, no espaço escolar, como mediador do conhecimento, a fim de, proporcionar de forma crítica, as transformações individuais e coletivas, juntamente da emancipação do indivíduo a favor das questões ambientais.Fil: Beck, Caroline. Universidad Federal da Fronteira Sul. Rio Grande do Sul; BrasilFil: Matos Uhmann, Rosangela Inês. Universidad Federal da Fronteira Sul. Rio Grande do Sul; Brasi

Response of the mantle to flat slab evolution: Insights from local S splitting beneath Peru

The dynamics of flat subduction, particularly the interaction between a flat slab and the overriding plate, are poorly understood. Here we study the (seismically) anisotropic properties and deformational regime of the mantle directly above the Peruvian flat slab. We analyze shear wave splitting from 370 local S events at 49 stations across southern Peru. We find that the mantle above the flat slab appears to be anisotropic, with modest average delay times (~0.28 s) that are consistent with ~4% anisotropy in a ~30 km thick mantle layer. The most likely mechanism is the lattice-preferred orientation of olivine, which suggests that the observed splitting pattern preserves information about the mantle deformation. We observe a pronounced change in anisotropy along strike, with predominately trench-parallel fast directions in the north and more variable orientations in the south, which we attribute to the ongoing migration of the Nazca Ridge through the flat slab system

Hypertension Programmed in Adult Hens by Isolated Effects of Developmental Hypoxia In Ovo.

In mammals, pregnancy complicated by chronic hypoxia can program hypertension in the adult offspring. However, mechanisms remain uncertain because the partial contributions of the challenge on the placenta, mother, and fetus are difficult to disentangle. Here, we used chronic hypoxia in the chicken embryo-an established model system that permits isolation of the direct effects of developmental hypoxia on the cardiovascular system of the offspring, independent of additional effects on the mother or the placenta. Fertilized chicken eggs were exposed to normoxia (N; 21% O2) or hypoxia (H; 13.5%-14% O2) from the start of incubation (day 0) until day 19 (hatching, ≈day 21). Following hatching, all birds were maintained under normoxic conditions until ≈6 months of adulthood. Hypoxic incubation increased hematocrit (+27%) in the chicken embryo and induced asymmetrical growth restriction (body weight, -8.6%; biparietal diameter/body weight ratio, +7.5%) in the hatchlings (all P<0.05). At adulthood (181±4 days), chickens from hypoxic incubations remained smaller (body weight, -7.5%) and showed reduced basal and stimulated in vivo NO bioavailability (pressor response to NG-nitro-L-arginine methyl ester, -43%; phenylephrine pressor response during NO blockade, -61%) with significant hypertension (mean arterial blood pressure, +18%), increased cardiac work (ejection fraction, +12%; fractional shortening, +25%; enhanced baroreflex gain, +456%), and left ventricular wall thickening (left ventricular wall volume, +36%; all P<0.05). Therefore, we show that chronic hypoxia can act directly on a developing embryo to program hypertension, cardiovascular dysfunction, and cardiac wall remodeling in adulthood in the absence of any maternal or placental effects.The British Heart Foundation The Wellcome Trus

Spectral library search for improved TMTpro labelled peptide assignment in human plasma proteomics

Funding Information: This work was supported by a research grant from the Danish Cardiovascular Academy, which is funded by the Novo Nordisk Foundation, grant number NNF20SA0067242 and the Danish Heart Foundation. Publisher Copyright: © 2023 The Authors. Proteomics published by Wiley-VCH GmbH.Clinical biomarker discovery is often based on the analysis of human plasma samples. However, the high dynamic range and complexity of plasma pose significant challenges to mass spectrometry-based proteomics. Current methods for improving protein identifications require laborious pre-analytical sample preparation. In this study, we developed and evaluated a TMTpro-specific spectral library for improved protein identification in human plasma proteomics. The library was constructed by LC-MS/MS analysis of highly fractionated TMTpro-tagged human plasma, human cell lysates, and relevant arterial tissues. The library was curated using several quality filters to ensure reliable peptide identifications. Our results show that spectral library searching using the TMTpro spectral library improves the identification of proteins in plasma samples compared to conventional sequence database searching. Protein identifications made by the spectral library search engine demonstrated a high degree of complementarity with the sequence database search engine, indicating the feasibility of increasing the number of protein identifications without additional pre-analytical sample preparation. The TMTpro-specific spectral library provides a resource for future plasma proteomics research and optimization of search algorithms for greater accuracy and speed in protein identifications in human plasma proteomics, and is made publicly available to the research community via ProteomeXchange with identifier PXD042546.publishersversionepub_ahead_of_prin