576 research outputs found
Observation of a quenched moment of inertia in a rotating strongly interacting Fermi gas
We make a model-independent measurement of the moment of inertia of a
rotating, expanding strongly-interacting Fermi gas. Quenching of the moment of
inertia is observed for energies both below and above the superfluid
transition. This shows that a strongly interacting Fermi gas with angular
momentum can support irrotational flow in both the superfluid and collisional
normal fluid regimes.Comment: 4 pages 5 figure
Synthetic Biology Open Language Visual (SBOL Visual) Version 2.0
People who are engineering biological organisms often find it useful to communicate in diagrams, both about the structure of the nucleic acid sequences that they are engineering and about the functional relationships between sequence features and other molecular species. Some typical practices and conventions have begun to emerge for such diagrams. The Synthetic Biology Open Language Visual (SBOL Visual) has been developed as a standard for organizing and systematizing such conventions in order to produce a coherent language for expressing the structure and function of genetic designs. This document details version 2.0 of SBOL Visual, which builds on the prior SBOL Visual 1.0 standard by expanding diagram syntax to include functional interactions and molecular species, making the relationship between diagrams and the SBOL data model explicit, supporting families of symbol variants, clarifying a number of requirements and best practices, and significantly expanding the collection of diagram glyphs
Testing the IMEter on rice introns and other aspects of intron-mediated enhancement of gene expression
In many eukaryotes, spliceosomal introns are able to influence the level and site of gene expression. The mechanism of this Intron Mediated Enhancement (IME) has not yet been elucidated, but regulation of gene expression is likely to occur at several steps during and after transcription. Different introns have different intrinsic enhancing properties, but the determinants of these differences remain unknown. Recently, an algorithm called IMEter, which is able to predict the IME potential of introns without direct testing, has been proposed. A computer program was developed for Arabidopsis thaliana and rice (Oryza sativa L.), but was only tested experimentally in Arabidopsis by measuring the enhancement effect on GUS expression of different introns inserted within otherwise identical plasmids. To test the IMEter potential in rice, a vector bearing the upstream regulatory sequence of a rice β-tubulin gene (OsTub6) fused to the GUS reporter gene was used. The enhancing intron interrupting the OsTub6 5′-UTR was precisely replaced by seven other introns carrying different features. GUS expression level in transiently transformed rice calli does not significantly correlate with the calculated IMEter score. It was also found that enhanced GUS expression was mainly due to a strong increase in the mRNA steady-state level and that mutations at the splice recognition sites almost completely abolished the enhancing effect. Splicing also appeared to be required for IME in Arabidopsis cell cultures, where failure of the OsTub6 5′ region to drive high level gene expression could be rescued by replacing the poorly spliced rice intron with one from Arabidopsis
La coopération pour le meilleur usage possible des ressources phytogénétiques en Afrique de l'Ouest et centrale : un impératif régional
Les ressources phytogénétiques pour l'alimentation et l'agriculture représentent un précieux héritage des peuples d’Afrique de l’Ouest et du Centre. La région est dotée d'agroécosystèmes diversifiés dont la diversité des cultures joue un rôle essentiel en contribuant à la fourniture de nourriture et des services éco-systémiques. Cependant, le défi devient de plus en plus croissant pour assurer l’utilisation durable et la conservation pour les générations futures. Par exemple, dans certaines parties de la région la diversité des cultures locales est menacée par un certain nombre de facteurs, dont des pratiques agricoles non durables, la modification des préférences alimentaires, l'urbanisation et le changement climatique. Il est toutefois encourageant de constater qu'en dépit de ces défis, il y a une prise de conscience croissante de l'importance des ressources phytogénétiques en Afrique de l’Ouest et du Centre. Cette publication fait la revue des efforts de collaboration des principaux acteurs de la sous-région au cours des dix dernières années, depuis les programmes de conservation jusqu’aux directives régionales de haut niveau et aux efforts nationaux pour participer au système multilatéral d'accès et de partage des avantages du Traité International sur les Ressources Phytogénétiques pour l'Alimentation et l'Agriculture. Dans l'ensemble, ces documents font un plaidoyer convaincant pour la coopération sous régionale (et mondiale) accrue pour l’utilisation et la conservation durable et équitable des ressources phytogénétiques
Cooperating to make the best use of plant genetic resources in West and Central Africa: a regional imperative
Plant genetic resources for food and agriculture are a precious heritage of the people of West and Central Africa. The region is endowed with diversified agroecosystems in which crop diversity plays an integral role by contributing to the provision of food and ecosystem services. There is a growing challenge, however, in ensuring that those resources are sustainability used and conserved for future generations. For example, in some parts of the region in situ crop diversity is threatened by a number of factors including unsustainable farming practices, changing food preferences, urbanization, and climate change. It is encouraging to note that despite these challenges, there is a growing awareness of the importance of plant genetic resources in West and Central Africa. This publication presents an overview of the collaborative efforts of key actors in the subregion over the last 10 years, from conservation programmes, to high-level regional directives, to national efforts to participate in the multilateral system of access and benefit sharing of the International Treaty on Plant Genetic Resources for Food and Agriculture. Overall, these papers make a compelling case for continued subregional (and global) cooperation to sustainably and equitably use and conserve plant genetic resources
Synthetic biology open language visual (SBOL Visual) version 2.3
People who are engineering biological organisms often find it useful to communicate in diagrams, both about the structure of the nucleic acid sequences that they are engineering and about the functional relationships between sequence features and other molecular species. Some typical practices and conventions have begun to emerge for such diagrams. The Synthetic Biology Open Language Visual (SBOL Visual) has been developed as a standard for organizing and systematizing such conventions in order to produce a coherent language for expressing the structure and function of genetic designs. This document details version 2.3 of SBOL Visual, which builds on the prior SBOL Visual 2.2 in several ways. First, the specification now includes higher-level "interactions with interactions," such as an inducer molecule stimulating a repression interaction. Second, binding with a nucleic acid backbone can be shown by overlapping glyphs, as with other molecular complexes. Finally, a new "unspecified interaction" glyph is added for visualizing interactions whose nature is unknown, the "insulator" glyph is deprecated in favor of a new "inert DNA spacer" glyph, and the polypeptide region glyph is recommended for showing 2A sequences
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Noninvasive Testing and Surrogate Markers in Invasive Fungal Diseases.
Invasive fungal infections continue to increase as at-risk populations expand. The high associated morbidity and mortality with fungal diseases mandate the continued investigation of novel antifungal agents and diagnostic strategies that include surrogate biomarkers. Biologic markers of disease are useful prognostic indicators during clinical care, and their use in place of traditional survival end points may allow for more rapid conduct of clinical trials requiring fewer participants, decreased trial expense, and limited need for long-term follow-up. A number of fungal biomarkers have been developed and extensively evaluated in prospective clinical trials and small series. We examine the evidence for these surrogate biomarkers in this review and provide recommendations for clinicians and regulatory authorities
Variable Nav1.5 Protein Expression from the Wild-Type Allele Correlates with the Penetrance of Cardiac Conduction Disease in the Scn5a+/− Mouse Model
BACKGROUND: Loss-of-function mutations in SCN5A, the gene encoding Na(v)1.5 Na+ channel, are associated with inherited cardiac conduction defects and Brugada syndrome, which both exhibit variable phenotypic penetrance of conduction defects. We investigated the mechanisms of this heterogeneity in a mouse model with heterozygous targeted disruption of Scn5a (Scn5a(+/-) mice) and compared our results to those obtained in patients with loss-of-function mutations in SCN5A. METHODOLOGY/PRINCIPAL FINDINGS: Based on ECG, 10-week-old Scn5a(+/-) mice were divided into 2 subgroups, one displaying severe ventricular conduction defects (QRS interval>18 ms) and one a mild phenotype (QRS53 weeks), ajmaline effect was larger in the severely affected subgroup. These data matched the clinical observations on patients with SCN5A loss-of-function mutations with either severe or mild conduction defects. Ventricular tachycardia developed in 5/10 old severely affected Scn5a(+/-) mice but not in mildly affected ones. Correspondingly, symptomatic SCN5A-mutated Brugada patients had more severe conduction defects than asymptomatic patients. Old severely affected Scn5a(+/-) mice but not mildly affected ones showed extensive cardiac fibrosis. Mildly affected Scn5a(+/-) mice had similar Na(v)1.5 mRNA but higher Na(v)1.5 protein expression, and moderately larger I(Na) current than severely affected Scn5a(+/-) mice. As a consequence, action potential upstroke velocity was more decreased in severely affected Scn5a(+/-) mice than in mildly affected ones. CONCLUSIONS: Scn5a(+/-) mice show similar phenotypic heterogeneity as SCN5A-mutated patients. In Scn5a(+/-) mice, phenotype severity correlates with wild-type Na(v)1.5 protein expression
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