1,014 research outputs found
Functional characterization of two newly identified Human Endogenous Retrovirus coding envelope genes
A recent in silico search for coding sequences of retroviral origin present in the human genome has unraveled two new envelope genes that add to the 16 genes previously identified. A systematic search among the latter for a fusogenic activity had led to the identification of two bona fide genes, named syncytin-1 and syncytin-2, most probably co-opted by primate genomes for a placental function related to the formation of the syncytiotrophoblast by cell-cell fusion. Here, we show that one of the newly identified envelope gene, named envP(b), is fusogenic in an ex vivo assay, but that its expression – as quantified by real-time RT-PCR on a large panel of human tissues – is ubiquitous, albeit with a rather low value in most tissues. Conversely, the second envelope gene, named envV, discloses a placenta-specific expression, but is not fusogenic in any of the cells tested. Altogether, these results suggest that at least one of these env genes may play a role in placentation, but most probably through a process different from that of the two previously identified syncytins
Efficient sweet pepper transformation mediated by the BABY BOOM transcription factor
Pepper (Capsicum L.) is a nutritionally and economically important crop that is cultivated throughout the world as a vegetable, condiment, and food additive. Genetic transformation using Agrobacterium tumefaciens (agrobacterium) is a powerful biotechnology tool that could be used in pepper to develop community-based functional genomics resources and to introduce important agronomic traits. However, pepper is considered to be highly recalcitrant for agrobacterium-mediated transformation, and current transformation protocols are either inefficient, cumbersome or highly genotype dependent. The main bottleneck in pepper transformation is the inability to generate cells that are competent for both regeneration and transformation. Here, we report that ectopic expression of the Brassica napus BABY BOOM AP2/ERF transcription factor overcomes this bottleneck and can be used to efficiently regenerate transgenic plants from otherwise recalcitrant sweet pepper (C. annuum) varieties. Transient activation of BABY BOOM in the progeny plants induced prolific cell regeneration and was used to produce a large number of somatic embryos that could be converted readily to seedlings. The data highlight the utility of combining biotechnology and classical plant tissue culture approaches to develop an efficient transformation and regeneration system for a highly recalcitrant vegetable crop
Noncritical quadrature squeezing through spontaneous polarization symmetry breaking
We discuss the possibility of generating noncritical quadrature squeezing by
spontaneous polarization symmetry breaking. We consider first type-II
frequency-degenerate optical parametric oscillators, but discard them for a
number of reasons. Then we propose a four-wave mixing cavity in which the
polarization of the output mode is always linear but has an arbitrary
orientation. We show that in such a cavity complete noise suppression in a
quadrature of the output field occurs, irrespective of the parameter values
Comprehensive search for intra- and inter-specific sequence polymorphisms among coding envelope genes of retroviral origin found in the human genome: genes and pseudogenes
BACKGROUND: The human genome carries a high load of proviral-like sequences, called Human Endogenous Retroviruses (HERVs), which are the genomic traces of ancient infections by active retroviruses. These elements are in most cases defective, but open reading frames can still be found for the retroviral envelope gene, with sixteen such genes identified so far. Several of them are conserved during primate evolution, having possibly been co-opted by their host for a physiological role. RESULTS: To characterize further their status, we presently sequenced 12 of these genes from a panel of 91 Caucasian individuals. Genomic analyses reveal strong sequence conservation (only two non synonymous Single Nucleotide Polymorphisms [SNPs]) for the two HERV-W and HERV-FRD envelope genes, i.e. for the two genes specifically expressed in the placenta and possibly involved in syncytiotrophoblast formation. We further show – using an ex vivo fusion assay for each allelic form – that none of these SNPs impairs the fusogenic function. The other envelope proteins disclose variable polymorphisms, with the occurrence of a stop codon and/or frameshift for most – but not all – of them. Moreover, the sequence conservation analysis of the orthologous genes that can be found in primates shows that three env genes have been maintained in a fully coding state throughout evolution including envW and envFRD. CONCLUSION: Altogether, the present study strongly suggests that some but not all envelope encoding sequences are bona fide genes. It also provides new tools to elucidate the possible role of endogenous envelope proteins as susceptibility factors in a number of pathologies where HERVs have been suspected to be involved
Addressing the Gender Gap in Computer Programming Through the Design and Development of Serious Games
The gap between male and female participation in computer science education and careers is a worldwide issue that must be addressed by introducing early methodological learning interventions that make computer science attractive to all, that is by answering the following issues: a) misperception among educators, learners, parents and youngsters on the suitability of computer science careers to girls and b) a wrong assumption of an insufficient preparedness to do it successfully. This article presents a European initiative - CODING4GIRLS - that proposes to teach coding through a game design and development process based on a design thinking methodological approach that is linked to creativity and human-centered solutions. In this methodology, students address increasingly complex real-life challenges by designing and developing awareness raising serious games for which they need to learn specific coding concepts.info:eu-repo/semantics/publishedVersio
Interference Effects in Relativistic Deuteron Electrodisintegration
We extend the relativistic plane--wave impulse approximation formalism to
incorporate a specific class of relativistic interference effects for use in
describing inclusive electrodisintegration of H. The role of these
``exchange'' terms for the various response functions accessible in
parity--conserving and --violating inclusive processes is investigated and
shown, especially for the latter, to have important consequences for
experiment. An extension to a simple quasi--deuteron model is also considered.Comment: 28 pages (latex), 15 figures available upon request, TRI-PP-93-101
and MIT-CTP#224
Students and teachers’ need for sustainable education: lessons from the pandemic
The COVID-19 pandemic challenged the sustainability of higher education as millions of students were forced out of school, shifting to online learning instead of in-class education. In the Erasmus+ project, Virtual Presence in Higher Education Hybrid Learning Delivery (VIE), we were concerned with the level of readiness and the ability of higher-education students and teachers to face this changing situation. This paper reports the results of a survey which assessed the experiences that students and teachers had during the pandemic and, in particular, the development of soft skills through active learning methodologies. The project results show that there are still some unmet needs, but existing digital technologies, tools, and platforms already provide valuable solutions both for students and teachers that ensure a continuation of high-quality learning experiences.Erasmus+ program | Ref. KA226-A280C01
Compostos fenólicos em vinhos e seus efeitos antioxidantes na prevenção de doenças
Phenolic compounds are widely spread in vegetable kingdom. Among fruits, grape (Vitis vinifera L.) is one of the most important source of phenolic compounds, like flavonoids (anthocyanidins and flavonones), stilbene (resveratrol), phenic acid (derived from cinnamic and benzoic acids) and a large variety of tannins. In the last decades, great attention has been directed to the free radicals participation in the pathogenesis of several non-transmissible diseases. Studies have proved the antioxidant properties of phenolic compounds in products made by grapes, especially red wine. Another wine compound is ethanol, which reinforces cardiovascular protection. This study had the objective of investigating the biological properties of phenolic compounds in wine, looking for their composition, chemical structure and antioxidant activity. It is equally important to keep in mind that wine can benefit health by moderate drinking. According to several researchers, a proper diet and the moderate wine consumption (300 mL/day) are adequate strategies to protect and enhance health through several physiological mechanisms.Os compostos fenólicos estão amplamente distribuídos no reino vegetal. Entre as frutas, a uva (Vitis vinifera L.) é uma das maiores fontes de compostos fenólicos. Os principais fenólicos presentes na uva são os flavonóides (antocianinas e flavonóis), os estilbenos (resveratrol), os ácidos fenólicos (derivados dos ácidos cinâmicos e benzóicos) e uma larga variedade de taninos. Nas últimas décadas, muita atenção tem sido direcionada ao envolvimento dos radicais livres na patogênese de diversas doenças não transmissíveis. Estudos comprovaram as propriedades antioxidantes dos compostos fenólicos presentes em produtos derivados da uva, especialmente o vinho tinto. Outro ingrediente presente no vinho é o etanol que reforça a proteção cardiovascular. Este trabalho teve como objetivo investigar as propriedades biológicas dos compostos fenólicos presentes em vinhos, abordando a composição, a estrutura química e a atividade antioxidante. É importante ressaltar que o vinho deve ser consumido com moderação, sendo que o consumo excessivo passa a ser fator de risco para doenças cardiovasculares e outras. Portanto, é oportuno manter uma dieta equilibrada. De acordo com diversos especialistas, o consumo de uma ou duas taças de vinho tinto por dia (300 mL), levando em conta uma boa absorção dos princípios ativos, é adequado para proteção do organismo por meio de diversos mecanismos fisiológicos
Optomechanical characterization of acoustic modes in a mirror
We present an experimental study of the internal mechanical vibration modes
of a mirror. We determine the frequency repartition of acoustic resonances via
a spectral analysis of the Brownian motion of the mirror, and the spatial
profile of the acoustic modes by monitoring their mechanical response to a
resonant radiation pressure force swept across the mirror surface. We have
applied this technique to mirrors with cylindrical and plano-convex geometries,
and compared the experimental results to theoretical predictions. We have in
particular observed the gaussian modes predicted for plano-convex mirrors.Comment: 8 pages, 8 figures, RevTe
Proposta de um novo modelo translacional para aplicação da estimulação transcraniana por corrente contínua em ratos: projeto piloto
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