2,469 research outputs found
Mimicry technology : a versatile tool for small RNA suppression
A decade ago the discovery of the target mimicry regulatory process on the activity of a mature microRNA (miRNA) enabled for the first time the customized attenuation of miRNA activity in plants. That powerful technology was named MIMIC and was based on engineering the IPS1 long noncoding transcript to become complementary to the miRNA under study. In order to avoid IPS1 degradation, the predicted miRNA-mediated cleavage site was interrupted by three additional nucleotides giving rise to the so-called MIMIC decoy. Since then, MIMIC technology has been used in several plant species and in basic and translational research. We here provide a detailed guide to produce custom-designed MIMIC decoys to facilitate the study of sRNA functions in plants
Sex chromosome and autosome divergence in Podisma (Orthoptera) in western Europe
International audienc
The Evershed Flow and the Brightness of the Penumbra
The Evershed flow is a systematic motion of gas that occurs in the penumbra
of all sunspots. Discovered in 1909, it still lacks a satisfactory explanation.
We know that the flow is magnetized, often supersonic, and that it shows
conspicuous fine structure on spatial scales of 0.2"-0.3", but its origin
remains unclear. The hope is that a good observational understanding of the
relation between the flow and the penumbral magnetic field will help us
determine its nature. Here I review advances in the characterization of the
Evershed flow and sunspot magnetic fields from high-resolution spectroscopic
and spectropolarimetric measurements. Using this information as input for 2D
heat transfer simulations, it has been demonstrated that hot Evershed upflows
along nearly horizontal field lines are capable of explaining one of the most
intriguing aspects of sunspots: the surplus brightness of the penumbra relative
to the umbra. They also explain the existence of penumbral filaments with dark
cores. These results support the idea that the Evershed flow is largely
responsible for the transport of energy in the penumbra.Comment: 18 pages, to appear in "Magnetic Coupling between the Interior and
the Atmosphere of the Sun", eds. S.S. Hasan and R.J. Rutten, Astrophysics and
Space Science Proceedings, Springer, Heidelberg, 200
Theoretical Models of Sunspot Structure and Dynamics
Recent progress in theoretical modeling of a sunspot is reviewed. The
observed properties of umbral dots are well reproduced by realistic simulations
of magnetoconvection in a vertical, monolithic magnetic field. To understand
the penumbra, it is useful to distinguish between the inner penumbra, dominated
by bright filaments containing slender dark cores, and the outer penumbra, made
up of dark and bright filaments of comparable width with corresponding magnetic
fields differing in inclination by some 30 degrees and strong Evershed flows in
the dark filaments along nearly horizontal or downward-plunging magnetic
fields. The role of magnetic flux pumping in submerging magnetic flux in the
outer penumbra is examined through numerical experiments, and different
geometric models of the penumbral magnetic field are discussed in the light of
high-resolution observations. Recent, realistic numerical MHD simulations of an
entire sunspot have succeeded in reproducing the salient features of the
convective pattern in the umbra and the inner penumbra. The siphon-flow
mechanism still provides the best explanation of the Evershed flow,
particularly in the outer penumbra where it often consists of cool, supersonic
downflows.Comment: To appear in "Magnetic Coupling between the Interior and the
Atmosphere of the Sun", eds. S.S. Hasan and R.J. Rutten, Astrophysics and
Space Science Proceedings, Springer-Verlag, Heidelberg, Berlin, 200
Genetic epidemiology of the Charcot-Marie-Tooth in the Spanish Gypsy population: the Hereditary Motor and Sensory Neuropathy type Russe in depth
[EN] Four private mutations responsible for three forms demyelinating of Charcot-Marie-Tooth (CMT) or hereditary motor and sensory neuropathy (HMSN) have been associated with the Gypsy population: the NDRG1 p.R148X in CMT type 4D (CMT4D/HMSN-Lom); p.C737_P738delinsX and p.R1109X mutations in the SH3TC2 gene (CMT4C); and a G>C change in a novel alternative untranslated exon in the HK1 gene causative of CMT4G (CMT4G/HMSN-Russe). Here we address the findings of a genetic study of 29 Gypsy Spanish families with autosomal recessive demyelinating CMT. The most frequent form is CMT4C (57.14%), followed by HMSN-Russe (25%) and HMSN-Lom (17.86%). The relevant frequency of HMSN-Russe has allowed us to investigate in depth the genetics and the associated clinical symptoms of this CMT form. HMSN-Russe probands share the same haplotype confirming that the HK1 g.9712G>C is a founder mutation, which arrived in Spain around the end of the 18th century. The clinical picture of HMSN-Russe is a progressive CMT disorder leading to severe weakness of the lower limbs and prominent distal sensory loss. Motor nerve conduction velocity was in the demyelinating or intermediate range.We thank all patients and their relatives for their kind collaboration. We also thank Drs G. Glover, R. Vilches, F. Galan, and C. Diaz for referring patients for genetic analysis. We also acknowledge F Barraclough for English corrections. This work was supported by the Instituto de Salud Carlos III (ISCIII) (grants number PI08/90857, PI08/0889, CP08/00053 and PS09/00095) co-funded with FEDER funds and by the ISCIII-IRDiRC Programme (TREAT-CMT grant). C. E. has a 'Miguel Servet' contract funded by the ISCIII. Both Centro de Investigacion Biomedica en Red de Enfermedades Raras (CIBERER) and Centro de Investigacion Biomedica en Red de Enfermedades Neurodegenerativas (CIBERNED) are initiative from the ISCIII.Sevilla, T.; Martínez-Rubio, D.; Márquez, C.; Paradas, C.; Colomer, J.; Jaijo, T.; Millán, J.... (2013). Genetic epidemiology of the Charcot-Marie-Tooth in the Spanish Gypsy population: the Hereditary Motor and Sensory Neuropathy type Russe in depth. Clinical Genetics. 83(6):565-570. https://doi.org/10.1111/cge.1201556557083
Evaluation of the potential index model to predict habitat suitability of forest species: the potential distribution of mountain pine (Pinus uncinata) in the Iberian peninsula
Characterization of the suitability or potentiality of a territory for forest tree species is an important source of information for forest planning and managing. In this study, we compared a relatively simple methodology to generate potential habitat distribution areas that has been traditionally used in Spain (the potential index model) with a statistical modelling approach (generalized linear model). We modelled the potential distribution of mountain pine (Pinus uncinata) in the Iberian peninsula as a working example. The potential index model generated a map of habitat suitability according to the values of an index of potentiality, whose distribution has usually divided into four categories based on quartiles (from optimum to low suitability). Considering all values of the index of potentiality as presences of mountain pine resulted in a low to moderate degree of agreement between the potential index model and the generalized linear model according to the kappa coefficient. Using the cut-off value of the index of potentiality that maximized the degree of agreement between both modelling approaches resulted in a substantial similarity between the maps of the predicted distribution of mountain pine. This cut-off value did lie in the upper-third quartile of the potential index distribution (high suitability category), and roughly coincided with the upper 30th percentile. The use of statistical techniques, which have proved to be powerful and versatile for species distribution modelling, is recommended. However, the potential index model, together with the adjustments proposed here, could be a reasonably simple methodology to predict the potential distribution of forest tree species that forest managers should take into account when evaluating forestation and afforestation projects
Increased circulating microRNAs miR-342-3p and miR-21-5p in natural sheep prion disease
Scrapie is a transmissible spongiform encephalopathy (TSE), or prion disease, of sheep and goats. As no simple diagnostic tests are yet available to detect TSEs in vivo, easily accessible biomarkers could facilitate the eradication of scrapie agents from the food chain. To this end, we analysed by quantitative reverse transcription PCR a selected set of candidate microRNAs (miRNAs) from circulating blood plasma of naturally infected, classical scrapie sheep that demonstrated clear scrapie symptoms and pathology. Significant scrapie-associated increase was repeatedly found for miR-342-3p and miR-21-5p. This is the first demonstration, to our knowledge, of circulating miRNA alterations in any animal suffering from TSE. Genome-wide expression studies are warranted to investigate the true depth of miRNA alterations in naturally occurring TSEs, especially in presymptomatic animals, as the presented study demonstrates the potential feasibility of miRNAs as circulating TSE biomarkers
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