746 research outputs found
SmedGD: the Schmidtea mediterranea genome database
The planarian Schmidtea mediterranea is rapidly emerging as a model organism for the study of regeneration, tissue homeostasis and stem cell biology. The recent sequencing, assembly and annotation of its genome are expected to further buoy the biomedical importance of this organism. In order to make the extensive data associated with the genome sequence accessible to the biomedical and planarian communities, we have created the Schmidtea mediterranea Genome Database (SmedGD). SmedGD integrates in a single web-accessible portal all available data associated with the planarian genome, including predicted and annotated genes, ESTs, protein homologies, gene expression patterns and RNAi phenotypes. Moreover, SmedGD was designed using tools provided by the Generic Model Organism Database (GMOD) project, thus making its data structure compatible with other model organism databases. Because of the unique phylogenetic position of planarians, SmedGD (http://smedgd.neuro.utah.edu) will prove useful not only to the planarian research community, but also to those engaged in developmental and evolutionary biology, comparative genomics, stem cell research and regeneration
Utilización de la Homeopatía en Canino con Tumor Venereo Transmisible (TVT) en la Ciudad de Florencia, Caquetá.
El paciente del presente caso clínico es Taylor, un canino mestizo, macho, de aproximadamente tres años de edad, a éste canino se le realizó el respectivo exámen semiológico, presentando problemas a nivel genital, por la evidencia de una masa en la base del pene, creando un abultamiento notable a la inspección, en los antecedentes se encontró que meses antes presento una descargaprepucial hemorrágica. Con la sintomatología observada se realizarón diversos análisis clínicos de laboratorio, en los cuales se evidencio la presencia de un tumor venéreo transmisible. Se instauró un tratamiento horneopático, el cual se componía de dos partes, 1a primera era un suero homeopátizado cada 1 5 días y la segunda una hemoterapia cada cinco días por üa intravenosa. Después de 40 días de tratamiento, los resultados no fueron favorables, por 1o cual se decidió utili zar el tratamiento habitual para contrarrestar el tumor
Regenerative capacity in newts is not altered by repeated regeneration and ageing
The extent to which adult newts retain regenerative capability remains one of the greatest unanswered questions in the regeneration field. Here we report a long-term lens regeneration project spanning 16 years that was undertaken to address this question. Over that time, the lens was removed 18 times from the same animals, and by the time of the last tissue collection, specimens were at least 30 years old. Regenerated lens tissues number 18 and number 17, from the last and the second to the last extraction, respectively, were analysed structurally and in terms of gene expression. Both exhibited structural properties identical to lenses from younger animals that had never experienced lens regeneration. Expression of mRNAs encoding key lens structural proteins or transcription factors was very similar to that of controls. Thus, contrary to the belief that regeneration becomes less efficient with time or repetition, repeated regeneration, even at old age, does not alter newt regenerative capacity
Long-term alterations in brain and behavior after postnatal Zika virus infection in infant macaques
Zika virus (ZIKV) infection has a profound impact on the fetal nervous system. The postnatal period is also a time of rapid brain growth, and it is important to understand the potential neurobehavioral consequences of ZIKV infection during infancy. Here we show that postnatal ZIKV infection in a rhesus macaque model resulted in long-term behavioral, motor, and cognitive changes, including increased emotional reactivity, decreased social contact, loss of balance, and deficits in visual recognition memory at one year of age. Structural and functional MRI showed that ZIKV-infected infant rhesus macaques had persistent enlargement of lateral ventricles, smaller volumes and altered functional connectivity between brain areas important for socioemotional behavior, cognitive, and motor function (e.g. amygdala, hippocampus, cerebellum). Neuropathological changes corresponded with neuroimaging results and were consistent with the behavioral and memory deficits. Overall, this study demonstrates that postnatal ZIKV infection in this model may have long-lasting neurodevelopmental consequences
Seismological Parametrization of the November 30, 2018 Seismic Event, Buenos Aires, Argentina
El 30 de noviembre de 2018 ocurrió un sismo al SE de la ciudad de Buenos Aires, Argentina. Fue percibido por gran parte de la poblaciónen la zona epicentral en el Cratón del Río de la Plata, considerado como una zona continental estable. Utilizando tiempos dearribos de ondas P y S en 12 trazas sísmicas registradas por estaciones sismológicas de Argentina, Uruguay y Brasil a distancias epicentralesentre 11 y 900 km, se determinó el hipocentro 34,9°S, 58,23°O y 19 km de profundidad. Se estimaron las magnitudes local(ML=3,9) y momento (MW=3,7). Se calculó el mecanismo focal obteniendo dos posibles planos de fallamiento de acimut δ=112°/234°,buzamiento α=68°/38º y ángulo del vector desplazamiento λ=122°/38°. Se analizaron 150 datos de percepción reportados por lapoblación para determinar intensidades sísmicas de Mercalli Modificada IMM en la zona epicentral, incluyendo máximos de IMM=IV.Nuestros resultados (δ=112°, α=68° y λ=122°) muestran buena correlación con estructuras orientadas ONO del sistema de fallas Paranáy con el patrón de la distribución de IMM en sentido NO-SE. Menor correlación se observa entre los parámetros hallados del otroposible plano de falla y estructuras de antiguos fallamientos orientadas en sentido SO-NE. Se determinó un modelo de velocidadessísmicas para el Cratón del Río de la Plata sobre la base de estudios previos. La localización sísmica se obtuvo considerando esemodelo y luego, se comparó con otras localizaciones utilizando otro modelo de velocidades sísmicas promedio de Argentina y condeterminaciones sísmicas globales para el hipocentro y magnitud.The earthquake on 30 November 2018 had an epicenter to the southeast of Buenos Aires city, Argentina. The event was felt by many people in the epicentral zone in the Río de la Plata Craton, which is considered as a stable continental zone. We determined the hypocenter at 34.9°S, 58.23°W and 19 km depth using P and S-wave arrival times of 12 seismic traces recorded by seismological stations of Argentina, Uruguay and Brazil, at epicentral distances between 11 and 900 km. The local (ML=3.9) and moment (Mw=3.7) magnitudes were also estimated. The calculated focal mechanism indicates two possible fault planes with azimuth δ=112°/234°, dip α=68°/38° and rake λ=122°/38°. 150 perception reports from the population were analyzed in order to determine Modified Mercalli seismic intensities (MMI) in the epicentral area, including maximum values of IV. Our results (δ =112°, α=68° and λ=122°) show a good correlation with the WNW trend of the Paraná Fault System structures and with the pattern of MMI of a NW-SE orientation. Less correlation between the parameters determined for the other possible fault plane and old faulting structures of SW-NE trend is found. Based on previous studies a seismic velocity model was determined for the Río de la Plata Craton. The seismic location was obtained considering this velocity model. Then, it was compared with other locations using another average seismic velocities model of Argentina and global seismic determinations for the hypocenter and magnitude.Fil: Venerdini, Agostina Lia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; ArgentinaFil: López, Luciana. Provincia de San Juan. Ministerio de Planificación Federal, Inversion Publica y Servicios. Secretaria de Obras Publicas. Instituto Nacional de Prevención Sismica; ArgentinaFil: Orozco, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Sanchez, Gerardo. Provincia de San Juan. Ministerio de Planificación Federal, Inversion Publica y Servicios. Secretaria de Obras Publicas. Instituto Nacional de Prevención Sismica; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; ArgentinaFil: Alvarado, Patricia Monica. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Perucca, Laura Patricia A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Geología "Dr. Emiliano Aparicio"; ArgentinaFil: Galván, Romina de Los Angeles. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Laboratorio Geo - Aggo.; Argentin
Responsiveness of pituitary to galanin throughout the reproductive cycle of male European sea bass (Dicentrarchus labrax)
The neuropeptide galanin (Gal) is a putative factor regulating puberty onset and reproduction through its actions on the pituitary. The present study investigated the pituitary responsiveness to galanin and the patterns of galanin receptors (Galrs) expression throughout the reproductive cycle of two years old male European sea bass (Dicentrarchus labrax), an important aquaculture species. Quantitative analysis of pituitary and hypothalamus transcript expression of four galr subtypes revealed differential regulation according to the testicular developmental stage, with an overall decrease in expression from the immature stage to the mid-recrudescence stage. Incubation of pituitary cells with mammalian 1-29 Gal peptide induced significant changes in cAMP concentration, with sensitivities that varied according to the testicular development stages. Furthermore 1-29 Gal was able to stimulate both follicle stimulating hormone (Fsh) and luteinizing hormone (Lh) release from pituitary cell suspensions. The magnitude of the effects and effective concentrations varied according to reproductive stage, with generalized induction of Fsh and Lh release in animals sampled in January (full spermiation). The differential expression of galrs in pituitary and hypothalamus across the reproductive season, together with the differential effects of Gal on gonadotropins release in vitro strongly suggests the involvement of the galaninergic system in the regulation the hypothalamus-pituitary-gonad axis of male sea bass. This is to our knowledge the first clear evidence for the involvement of galanin in the regulation of reproduction in non-mammalian vertebrates. (C) 2017 Elsevier Inc. All rights reserved.European Union Seventh Framework Programme [262336]Spanish Ministry of Science and Innovation (MICINN)Spanish Ministry of the Economy and Competitiveness (MINECO) [AGL2009-11086]Spanish Ministry of the Economy and CompetitivenessRegional Government of Valencia [PROME-TEOH/2014/051]info:eu-repo/semantics/acceptedVersio
Combining Classical and Molecular Approaches Elaborates on the Complexity of Mechanisms Underpinning Anterior Regeneration
The current model of planarian anterior regeneration evokes the establishment of low levels of Wnt signalling at anterior wounds, promoting anterior polarity and subsequent elaboration of anterior fate through the action of the TALE class homeodomain PREP. The classical observation that decapitations positioned anteriorly will regenerate heads more rapidly than posteriorly positioned decapitations was among the first to lead to the proposal of gradients along an anteroposterior (AP) axis in a developmental context. An explicit understanding of this phenomenon is not included in the current model of anterior regeneration. This raises the question what the underlying molecular and cellular basis of this temporal gradient is, whether it can be explained by current models and whether understanding the gradient will shed light on regenerative events. Differences in anterior regeneration rate are established very early after amputation and this gradient is dependent on the activity of Hedgehog (Hh) signalling. Animals induced to produce two tails by either Smed-APC-1(RNAi) or Smed-ptc(RNAi) lose anterior fate but form previously described ectopic anterior brain structures. Later these animals form peri-pharyngeal brain structures, which in Smed-ptc(RNAi) grow out of the body establishing a new A/P axis. Combining double amputation and hydroxyurea treatment with RNAi experiments indicates that early ectopic brain structures are formed by uncommitted stem cells that have progressed through S-phase of the cell cycle at the time of amputation. Our results elaborate on the current simplistic model of both AP axis and brain regeneration. We find evidence of a gradient of hedgehog signalling that promotes posterior fate and temporarily inhibits anterior regeneration. Our data supports a model for anterior brain regeneration with distinct early and later phases of regeneration. Together these insights start to delineate the interplay between discrete existing, new, and then later homeostatic signals in AP axis regeneration
A Low Percent Ethanol Method for Immobilizing Planarians
Planarians have recently become a popular model system for the study of adult stem cells, regeneration and polarity. The system is attractive for both undergraduate and graduate research labs, since planarian colonies are low cost and easy to maintain. Also in situ hybridization, immunofluorescence and RNA-interference (RNAi) gene knockdown techniques have been developed for planarian studies. However, imaging of live worms (particularly at high magnifications) is difficult because animals are strongly photophobic; they quickly move away from light sources and out of frame. The current methods available to inhibit movement in planarians include RNAi injection and exposure to cold temperatures. The former is labor and time intensive, while the latter precludes the use of many fluorescent reporter dyes. Here, we report a simple, inexpensive and reversible method to immobilize planarians for live imaging. Our data show that a short 1 hour treatment with 3% ethanol (EtOH) is sufficient to inhibit both the fine and gross movements of Schmidtea mediterranea planarians, of the typical size used (4–6 mm), with full recovery of movement within 3–4 hours. Importantly, EtOH treatment did not interfere with regeneration, even after repeated exposure, nor lyse epithelial cells (as assayed by H&E staining). We demonstrate that a short exposure to a low concentration of EtOH is a quick and effective method of immobilizing planarians, one that is easily adaptable to planarians of all sizes and will increase the accessibility of live imaging assays to planarian researchers
Molecular motors robustly drive active gels to a critically connected state
Living systems often exhibit internal driving: active, molecular processes
drive nonequilibrium phenomena such as metabolism or migration. Active gels
constitute a fascinating class of internally driven matter, where molecular
motors exert localized stresses inside polymer networks. There is evidence that
network crosslinking is required to allow motors to induce macroscopic
contraction. Yet a quantitative understanding of how network connectivity
enables contraction is lacking. Here we show experimentally that myosin motors
contract crosslinked actin polymer networks to clusters with a scale-free size
distribution. This critical behavior occurs over an unexpectedly broad range of
crosslink concentrations. To understand this robustness, we develop a
quantitative model of contractile networks that takes into account network
restructuring: motors reduce connectivity by forcing crosslinks to unbind.
Paradoxically, to coordinate global contractions, motor activity should be low.
Otherwise, motors drive initially well-connected networks to a critical state
where ruptures form across the entire network.Comment: Main text: 21 pages, 5 figures. Supplementary Information: 13 pages,
8 figure
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