AFLP characterization of three argentine Coprotus species
Ramos, Araceli Marcela; Tadic, Luis Franco; Policelli, Nahuel; Ferreyra, Laura Ines; Cinto, Isabel Esther
AFLP methodology was applied to characterize three Coprotus species (C. lacteus, C. niveus, C. sexdecimsporus) so as to estimate the levels of polymorphism within species, to analyze the phenetic relationships among them, and to contrast the AFLP findings to those of a previous RAPD study. The high number of AFLP bands obtained with the six assayed primers allowed us to detect intra-specific variability. The genetic variability within species obtained using AFLP (measured in terms of percentage of polymorphic loci) was two to three times higher than those obtained by RAPD. The phenograms generated by AFLP markers grouped all strains of the same species into three defined clusters, and a higher association between C. lacteus and C. sexdecimsporus was also observed. The AFLP technique could become a powerful tool for genera such as Coprotus, in which a high intra-specific homogeneity does not allow detection of genetic variability using other PCR-based markers.
The chromosomes of the rare and endemic genus Famatinanthus (Famatinanthoideae, Asteraceae); Los cromosomas del raro y endémico género Famatinanthus (Famatinanthoideae, Asteraceae)
Chiarini, Franco Ezequiel; Barboza, Gloria Estela; Cantero, Juan Jose
Classical staining and in situ fluorescent hybridization with probes for the 18?5.8?26S and 5Sgenes were performed in Famatinathus decussatus (endemic from Argentina), in order to knowits main chromosomal characteristics and to compare them to related genera. The species is apaleopolyploid with 2n = 54, likely originated from x=9, and its karyotype features are conservative:one pair of 5S signals and two of 18?5.8?26S per complement were found. All the data are congruentwith the basal position of this species in the Asteraceae phylogenies.; Los cromosomas del raro y endémico género Famatinanthus. Se aplicaron tinción convencional e hibridación in situ fluorescente con sondas para los genes de 18–5.8–26S y 5S en Famatinathus decussatus (endémica de Argentina), con el fin de conocer su características cromosómicas principales y compararlas con géneros relacionados. La especie es un paleopoliploide con 2n = 54, probablemente originado a partir de x=9; sus caracteres cariotípicos son conservados: se encontraron un par de señales de 5S por complemento y dos de 18–5.8–26S. Los datos son congruentes con la posición basal que esta especie ocupa en las filogenias de Asteraceae.
Histopathological biomarkers in juvenile silver catfish (Rhamdia quelen) exposed to a sublethal lead concentration
Muñoz, Lautaro; Weber, Paula; Dressler, Valderi; Baldisserotto, Bernardo; Vigliano, Fabricio Andrés
The aim of this study was to determine the 96-h lethal concentration (96-h LC50) of lead (Pb) in silver catfish, Rhamdia quelen, and to determine histopathological biomarkers in fish exposed for 96-h to a sublethal concentration at 25% of the LC50. The 96-h LC50 was 108 mg l−1. In gills, the length and thickness of lamella and thickness of the filament epithelium were significantly higher in fish exposed to Pb for 48-h than in control fish whereas the interlamellar distance decreased. In the liver, the area occupied by lipid droplets and size of hepatocytes showed significantly higher values after 24-h of exposure. The percentage of abnormal renal tubules was higher in fish exposed to Pb, exhibiting a time-dependent increase. These variations in histopathological biomarkers permit the definition of the overall response of R. quelen to Pb and the potential usefulness in the monitoring of Pb contamination.
Isolation and characterization of 20 polymorphic microsatellite loci in the migratory freshwater fish Leporinus obtusidens (Characiformes: Anostomidae) using 454 shotgun pyrosequencing
Villanova, Gabriela Vanina; Vera, Manuel; Díaz, Juan; Martinez, Paulino; Calcaterra, Nora Beatriz; Arranz, Silvia Eda
Twenty polymorphic microsatellite markers were developed for the Neotropical fish Leporinus obtusidens using a next generation sequencing approach and tested in two other characifomes species, Schizodon platae and Prochilodus lineatus. Microsatellite loci alleles in L. obtusidens ranged between 2 and 20 alleles per locus (mean = 5·7), with expected heterozygosity values ranging from 0·097 to 0·956 (mean = 0·578) and observed heterozygosity values ranging from 0·000 to 0·800 (mean = 0·400) in a sample of 20 specimens from the lower Paraná River (Argentina). Most of these markers will be a valuable tool for captive breeding and stocking programmes, as well as for analyses of population connectivity and genetic structure in this broadly distributed Neotropical migratory fish.
Control de las condiciones ambientales y de iluminación en el Museo Casa Histórica de la Independencia
Zamora, María Silvana
Los profesionales de los museos son cada vez más conscientes de la importancia del control climático dentro de sus edificios. Los evidentes deterioros sufridos durante las exposiciones han llevado a considerar al ambiente como un agente que decididamente influirá en la integridad de los objetos expuestos, pudiendo afectar en forma definitiva algún elemento de su composición. Más aún, en ciudades históricas, son muchos los museos que se albergan en edificios históricos que no han sido diseñadas para este propósito pero han sido reacondicionados para la exhibición del patrimonio.
El objetivo de este trabajo fue evaluar si las condiciones ambientales a las que se someten dos obras de alto valor histórico del Museo Casa Histórica de la Independencia de la provincia de Tucumán (Argentina) acuerdan con las normas de conservación. Se midió diariamente la temperatura, humedad e iluminación de febrero a abril de 2013. Otro estudio consistió en analizar la carga térmica aportada por grupos visitantes. Los resultados indican que la iluminación es adecuada para la exhibición de este tipo de obras, y no así la temperatura y humedad. El análisis térmico confirma la importancia de restringir el flujo de visitantes para evitar daños aún mayores por variaciones de temperatura.
Expression of the tetrahydrofolate-dependent nitric oxide synthase from the green alga Ostreococcus tauri increases tolerance to abiotic stresses and influences stomatal development in Arabidopsis
Foresi, Noelia Pamela; Mayta, Martín Leonardo; Lodeyro, Anabella Fernanda; Scuffi, Denise; Correa Aragunde, Maria Natalia; Garcia-Mata, Carlos; Casalongue, Claudia; Carrillo, Nestor Jose; Lamattina, Lorenzo
Nitric oxide (NO) is a signaling molecule with diverse biological functions in plants. NO plays a crucial role in growth and development, from germination to senescence, and is also involved in plant responses to biotic and abiotic stresses. In animals, NO is synthesized by well-described nitric oxide synthase (NOS) enzymes. NOS activity has also been detected in higher plants, but no gene encoding an NOS protein, or the enzymes required for synthesis of tetrahydrobiopterin, an essential cofactor of mammalian NOS activity, have been identified so far. Recently, an NOS gene from the unicellular marine alga Ostreococcus tauri (OtNOS) has been discovered and characterized. Arabidopsis thaliana plants were transformed with OtNOS under the control of the inducible short promoter fragment (SPF) of the sunflower (Helianthus annuus) Hahb-4 gene, which responds to abiotic stresses and abscisic acid. Transgenic plants expressing OtNOS accumulated higher NO concentrations compared with siblings transformed with the empty vector, and displayed enhanced salt, drought and oxidative stress tolerance. Moreover, transgenic OtNOS lines exhibited increased stomatal development compared with plants transformed with the empty vector. Both in vitro and in vivo experiments indicate that OtNOS, unlike mammalian NOS, efficiently uses tetrahydrofolate as a cofactor in Arabidopsis plants. The modulation of NO production to alleviate abiotic stress disturbances in higher plants highlights the potential of genetic manipulation to influence NO metabolism as a tool to improve plant fitness under adverse growth conditions.
Histopathological biochemical evidence of hepatopancreatic toxicity caused by cadmium in white shrimp, Palaemonetes argentinus.
Chiodi Boudet, Leila Natalia; Polizzi, Paula Sabrina; Romero, María Belén; Robles, Alicia Daniela; Marcovecchio, Jorge Eduardo; Gerpe, Marcela Silvia
Cadmium (Cd) is one of the most common pollutants in the environment and induces a range of tissue changes or damages and organ dysfunction. The histopathological effects of Cd and lipid peroxidation (LPO) on hepatopancreas of the freshwater shrimp, Palaemonetes argentinus, were studied. Shrimp were obtained from two lagoons with contrasting environmental quality, De los Padres (LP, impacted site) and Nahuel Rucá (NR, reference site), and were exposed to 3.06 and 12.24 µg Cd L−1 for 3, 7, 10 and 15 days. The health status of both populations was also evaluated by histological analysis of control individuals. After exposure, shrimp were transferred to clean water for 28 days to evaluate the recuperation capacity of hepatopancreas. Control shrimp from NR exhibited a normal hepatopancreas structure; unlike control shrimp from LP which showed several alterations. These results were attributed to the different environmental quality of lagoons. The exposure to Cd resulted in several alterations in the histological structure of the hepatopancreas of both populations. The observed alterations included haemocytic and connective infiltrations in the intertubular space, erosioned microvilli, ripple of basal lamina, atrophied epithelium and necrosis, however, the latter was only observed in shrimp from LP. The exposure also caused an increase of LPO levels in both populations. P. argentinus was able to repair the hepatopancreas structure from the damage caused by Cd, evidenced by the histopathological results and LPO levels. Obtained results are indicating that the histological analysis of the hepatopancreas proved to be a highly sensitive method for evaluating water quality, in both environmental and laboratory conditions.
Factors Triggering Cyanobacteria Dominance and Succession During Blooms in a Hypereutrophic Drinking Water Supply Reservoir
Fernandez, Carolina; Estrada, Vanina Gisela; Parodi, Elisa Rosalia
As freshwater bodies become enriched in nutrients, there is a shift in the phytoplankton community toward dominance by cyanobacteria. Cyanobacterial blooms are a significant problem in water supply reservoirs worldwide because some species can release toxic compounds and are also associated with the production of bad odor and taste. The aims of this paper were to elucidate the mechanism inducing the development of cyanobacterial blooms and to understand the species succession during the bloom, as well as the influence of abiotic factors on the species composition. Total phosphorus level and parameters related to seasonality, i.e., temperature and solar radiation, were the factors triggering the development of the blooms. Blooms were dominated by Microcystis natans and Anabaena circinalis. Phosphorus was an important limiting factor for Anabaena development but never limited Microcystis growth. Water temperature was optimum until end of February for Anabaena, whereas Microcystis growth was slightly limited since water temperature never reached the optimal. Solar radiation was more limiting than temperature, and the decrease in light had a strong role in the bloom decline. Four species of cyanobacteria recorded in Paso de las Piedras reservoir are potentially toxic: Snowella fennica, Microcystis aeruginosa, Planktothrix agardhii, and A. circinalis, being the last one as the most abundant species during the blooms. Considering the Alert Level Framework for cyanobacteria, alert level 2 was exceeded only during blooms while alert level 1 was exceeded during almost all the year.
El mapa social de Tandil
Linares, Santiago; Velázquez, Guillermo Angel
La segregación socioespacial, también denominada segregación social del espacio urbano, segregación residencial o simplemente segregación urbana, es un concepto que hace referencia a la existencia de diferencias o desigualdades sociales dentro de un colectivo urbano y al agrupamiento de los sujetos según atributos específicos (socioeconómicos, culturales, raciales, etc.) en conglomerados urbanos con tendencia a la homogeneización en su interior y a la reducción de las interacciones con el resto de los grupos
Defining the Resource Perspective in the Development of Processes-Aware Information Systems
Stroppi, Luis Jesús Ramón; Chiotti, Omar Juan Alfredo; Villarreal, Pablo David
Context The resource perspective has impact on the performance of business processes. However, current Workflow Management Systems (WfMSs) provide disparate support to its implementation and business process modeling languages provide limited capabilities for its definition. Thus, it is difficult to specify requirements regarding this perspective and to select an appropriate WfMS to support them in order to obtain a technological solution aligned with the organizational needs. Objective To provide support to the definition, implementation, verification and validation of resource perspective requirements in the development of Process-Aware Information Systems (PAISs) based on WfMSs. Method The following activities were carried out: (i) identification of resource perspective aspects in executable workflow specifications, (ii) analysis of the elements provided by the BPMN modeling language to represent these aspects, (iii) development of a framework based on BPMN for defining and implementing these aspects by using the extension mechanism provided by this language, (iv) development of a model-driven development method that leverages the framework to develop PAISs, and (v) validation of the proposed framework and method through the development of a tool supporting them, a case study, and the evaluation against the Workflow Resource Patterns. Results A framework, a method and a tool that support the definition of the resource perspective in the development of PAISs. Conclusion By using the proposed framework and method, practitioners are able to: define the resource perspective requirements in conceptual process models, select a WfMS as implementation platform, and define the implementation of these requirements maintaining the consistency between the conceptual process models and the workflow specifications.
Representaciones privadas y sentidos colectivos: religión y militancia en las instituciones judías de la Argentina durante la dictadura (1976-1983)
Schenquer, Laura
Mientras en la última dictadura militar argentina (1976-1983) el terror inducía a los individuos a retirarse del espacio público al privado, en el campo judío se producía un fenómeno de multiplicación de instituciones adheridas a una corriente religiosa llamada Conservative Judaism. En este artículo se analiza la adhesión del Ateneo de Lomas de Zamora (provincia de Buenos Aires). Se estudian los sentidos y representaciones que circulaban en torno a introducir una práctica religiosa. En esos años en los que las autoridades de la dictadura militar argentina buscaban remodelar a la sociedad y despolitizarla, el Conservative Judaism ofrecía nuclear al campo judío con una propuesta de vida religiosa adaptada a las pautas y normativas de la época.
Importancia de la Geodiversidad. Método de Inventarización y Valoración del Patrimonio Geológico; Geodiversity importance. An inventory and assessment method for Geoheritage
Medina, Walter Manuel
En el presente trabajo se plantea un método de análisis cuantitativo del patrimonio geológico de un área elegida. Esta importancia nace del hecho de que el patrimonio natural -donde se involucra a la riqueza geológica-, está cada vez más amenazada producto de actividades tales como la agricultura en grandes superficies, grandes infraestructuras, etc., trayendo aparejado un deterioro o incluso la desaparición de la herencia geológica, lo cual se traduce a un empobrecimiento del patrimonio de todos y de la historia geológica del mundo. El interés que se despertó por proteger estos bienes únicos e irreemplazables llevó al desarrollo de distintas técnicas o herramientas que contribuyen a la geoconservación. En este sentido, el desarrollo de la geoconservación a nivel internacional es bastante heterogéneo y también lo son sus planes de acción para conservar las riquezas geológicas y geomorfológicas. Existen varios métodos para esta práctica, en este caso se presenta una metodología en su etapa de inventario y cuantificación de los potenciales geositios.; A geoheritage quantitative analysis method applied to a chosen area is proposed. The natural heritage, involving geological richness, is increasingly threatened by activities such as large surface agriculture, infrastructures, etc., endangering the geological heritage, which translates to an impoverishment of the general heritage and the global geological history. The interest aroused by protecting these unique and irreplaceable assets, led to the development of different techniques or tools to geoconservation. As a matter of fact, the international development of geoconservation is quite heterogeneous and so are their action plans for protecting geological and geomorphological wealth. Several methods were defined for this practice, and in this opportunity, a methodology is proposed within the initial phase of inventory and quantification of potential geosites.
Pueblo, comunidad y mito en Juan Moreira de Leonardo Favio y en Facundo. La sombra del Tigre de Nicolás Sarquís
Suárez, Nicolás
El trabajo aborda dos transposiciones de textos de la literatura argentina del siglo XIX que fueron llevados al cine en el último tercio del siglo XX: Juan Moreira (Leonardo Favio, 1973) y Facundo. La sombra del tigre (Sarquís, 1995). A partir de la inscripción de ambos films en sus respectivos contextos histórico-políticos, se apunta a contrastar los modelos comunitarios que emanan de cada una de las obras, así como las figuraciones de los conceptos de pueblo y mito que ellas proponen.; This article addresses two film transpositions of texts from the Argentine literature of the 19th Century: Juan Moreira (Leonardo Favio, 1973) and Facundo. La sombra del tigre (Nicolás Sarquís, 1995), both produced in the last third of the 20th century. Through the inscription of both films in their respective historic and political contexts, I aim to contrast the community models that each film implies, as well as the corresponding figurations of the concepts of people and myth.; Este trabalho aborda duas transcrições de textos da literatura argentina do sé- culo XIX que foram adaptados ao cinema no último terço do século XX: Juan Moreira (Leonardo Favio, 1973), Facundo e La sombra del tigre (Nicolás Sarquís, 1995). A partir da inscrição de ambos os filmes em seus respectivos contextos histórico-político, pretende-se contrastar os modelos comunitários que emanam de cada uma das obras, bem como as figurações dos conceitos de povo e mito que elas propõem.
Decoherent time-dependent transport beyond the Landauer-Büttiker formulation: A quantum-drift alternative to quantum jumps
Fernández, Lucas Jonatan; Pastawski, Horacio Miguel
We develop and implement a model for decoherence in time-dependent transport. Inspired in a dynamical formulation of the Landauer-Büttiker equations, it boils down into a form of wave function that undergoes a smooth stochastic drift of the phase in a local basis, the quantum-drift (QD) model. This drift is nothing else but a local energy fluctuation. Unlike quantum-jumps (QJ) models, no jumps are present in the density as the evolution is unitary. As a first application, we address the transport through a resonant state |0〉 that undergoes decoherence. Its numerical resolution shows the equivalence with the decoherent steady-state transport in presence of a Büttiker's voltage probe. In order to test the dynamics we consider two many-spin systems, which are cases of experimental interest, where a local energy fluctuation is a natural phenomenon. A two-spin system is reduced to a two-level system (TLS) that oscillates among |0〉≡|↑↓〉 and |1〉≡|↓↑〉. We show that the QD model recovers not only the exponential damping of the oscillations in the low perturbation regime, but also the nontrivial bifurcation of the damping rates at a critical point, i.e., the quantum dynamical phase transition. We also address the spin-wave-like dynamics of local polarization in a spin chain. By averaging over Ns realizations, the QD solution has about half the dispersion respect to the mean dynamics than QJ. By evaluating the Loschmidt echo (LE), we find that the pure states |0〉≡|↑↓〉 and |1〉≡|↓↑〉 are quite robust against the local decoherence. In contrast, the LE, and hence coherence, decays faster when the system is in a superposition state (|↑↓〉±|↓↑〉)/2, which is consistent with the general trend recently observed in spin systems through NMR. Because of its simple implementation, the method is well suited to assess decoherent transport problems as well as to include decoherence in both one-body and many-body dynamics.
Exogenous GM1 ganglioside increases accumbal BDNF levels in rats
Valdomero, Analía; Perondi, María Cecilia; Orsingher, Otto Alberto; Cuadra, Gabriel R.
Gangliosides are compounds that are abundant throughout the CNS, participating actively in neuroplasticity. We previously described that exogenous GM1 ganglioside pretreatment enhances the rewarding properties of cocaine, evidenced by a lower number of sessions and/or dosage necessary to induce conditioned place preference (CPP). Since GM1 pretreatment did not modify cocaine's pharmacokinetic parameters, we suspected that the increased rewarding effect found might be mediated by BDNF, a neurotrophic factor closely related to cocaine addiction. This study was performed to investigate the possibility that GM1 may induce changes in BDNF levels in the nucleus accumbens (NAc), a core structure in the brain's reward circuitry, of rats submitted to three conditioning sessions with cocaine (10. mg/kg, i.p.). The results demonstrate that GM1 administration, which showed no rewarding effect by itself in the CPP, induced a significant increase of BDNF protein levels in the NAc, which may account for the increased rewarding effect of cocaine shown in the CPP paradigm.
The pattern of secreted molecules during the co-inoculation of alfalfa plants with Sinorhizobium meliloti and Delftia sp. strain JD2: An interaction that improves plant yield
Morel, M.A.; Cagide, C.; Minteguiaga, M.A.; Dardanelli, Marta Susana; Castro Sowinski, S.
Delftia sp. strain JD2 is a plant-growth-promoting bacterium that enhances legume nodulation and growth, acting as nodule-assisting bacterium during the co-inoculation of plants with rhizobial strains. In this work, we evaluate how the co-inoculation of alfalfa with Sinorhizobium meliloti U143 and JD2 increases plant yield under greenhouse conditions and we analyze the pattern of secreted bioactive compounds which may be involved in the microbe-plant communication. The chemical composition of extracellular cultures (EC) produced in hydroponic conditions (collected 4, 7, and 14 days after bacterial treatment) were characterized using different chromatographic and elucidation techniques. In addition, we assessed the effect that plant irrigation with cell-free EC, produced during co-inoculation experiments, would have on plant yield. Results showed increased alfalfa shoot and root matter, suggesting that U143-JD2 co-inoculation might be a beneficial agricultural practice. The pattern of secreted secondary metabolites among treatments showed important differences. Qualitative and quantitative changes in phenolic compounds (including flavonoids), organic acids, and volatile compounds were detected during the early microbe-plant interaction, suggesting that the production of some molecules positively affects the microbe-plant association. Finally, the irrigation of co-inoculated plants with cell-free EC under greenhouse conditions increased plant yield over agronomic expectations. This effect might be attributed to the bioactive secondary metabolites incorporated during the irrigation.
Nanointegracion: obtención controlada de nanoestructuras de oxido de Grafeno reducido interconectadas en áreas macroscopicamente extendidas mediante la técnica de Langmuir Blodgett
Herrera, Facundo Carlos; Ramallo Lopez, Jose Martin; Morales, Gustavo Marcelo; Lacconi, Gabriela Ines; Sanchez, Rodolfo Daniel; Lohr, Javier Hernán; Requejo, Felix Gregorio
El objetivo del presente trabajo es obtener películas delgadas de óxido de grafeno (GO) empleando la técnica de Langmuir-Blodgett (L-B) y posteriormente producir la reducción de la película, analizando distintos métodos, para obtener óxido de grafeno reducido (rGO). Con el objetivo de caracterizar als muestras de GO y rGO, las mismas fueron estudiadas por microscopía de fuerza atómica (AFM), micro-Raman y espectroscopía fotoelectrónica de rayos X (XPS) con resolución espacial nanométrica. Se realizaron además medidas de conductividad tanto a escala macro como nanométrica utilizando una estación de prueba y un nanomanipulador acoplado a un equipo de microscopía electrónica de barrido (SEM). Finalmente se correlacionaron el estado químico, la estructura y los defectos presentes en las películas delgadas de rGO con sus propiedades de transporte.
Plasma deposition of silver nanoparticles on ultrafiltration membranes: antibacterial and antibiofouling properties
Cruz, Mercedes Cecilia; Ruano Sandoval, Gonzalo Javier; Wolf, Marcus; Hecker, Dominic; Castro Vidaurre, Elza Fani; Schmittgens, Ralph; Rajal, Verónica Beatriz
tA novel and versatile plasma reactor was used to modify polyethersulphone commercial membranes. The equipmentwas applied to: (i) functionalize the membranes with low-temperature plasmas, (ii) deposit a film of poly(methylmethacrylate) (PMMA) by Plasma Enhanced Chemical Vapor Deposition (PECVD) and, (iii) deposit silver nanopar-ticles (SNP) by gas flow sputtering. Each modification process was performed in the same reactor consecutively,without exposure of the membranes to atmospheric air. Scanning electron microscopy and transmission electronmicroscopy were used to characterize the particles and modified membranes. SNP are evenly distributed on the mem-brane surface. Particle fixation and transport inside membranes were assessed before- and after-washing assays byX-ray photoelectron spectroscopy depth profiling analysis. PMMA addition improved SNP fixation. Plasma-treatedmembranes showed higher hydrophilicity. Anti-biofouling activity was successfully achieved against Gram-positive(Enterococcus faecalis) and -negative (Salmonella) Typhimurium bacteria. Therefore, disinfection by ultrafiltrationshowed substantial resistance to biofouling. The post-synthesis functionalization process developed provides a moreefficient fabrication route for anti-biofouling and anti-bacterial membranes used in the water treatment field. To thebest of our knowledge, this is the first report of a gas phase condensation process combined with a PECVD procedurein order to deposit SNP on commercial membranes to inhibit biofouling formation.
Sim1 is required for the migration and axonal projections of V3 interneurons in the developing mouse spinal cord
Blacklaws, Jake; Deska Gauthier, Dylan; Jones, Christopher T.; Petracca, Yanina Luján; Liu, Mingwei; Zhang, Han; Fawcett, James P.; Glover, Joel C.; Lanuza, Guillermo Marcos; Zhang, Ying
V3 spinal interneurons (INs) are a group of excitatory INs that play a crucial role in producing balanced and stable gaits in vertebrate animals. In the developing mouse spinal cord, V3 INs arise from the most ventral progenitor domain and form anatomically distinctive subpopulations in adult spinal cords. They are marked by the expression of transcription factor Sim1 postmitotically, but the function of Sim1 in V3 development remains unknown. Here, we used Sim1(Cre) ;tdTomato mice to trace the fate of V3 INs in a Sim1 mutant versus control genetic background during development. In Sim1 mutants, V3 INs are produced normally and maintain a similar position and organization as in wild types before E12.5. Further temporal analysis revealed that the V3 INs in the mutants failed to migrate properly to form V3 subgroups along the dorsoventral axis of the spinal cord. At birth, in the Sim1 mutant the number of V3 INs in the ventral subgroup was normal, but they were significantly reduced in the dorsal subgroup with a concomitant increase in the intermediate subgroup. Retrograde labeling at lumbar level revealed that loss of Sim1 led to a reduction in extension of contralateral axon projections both at E14.5 and P0 without affecting ipsilateral axon projections. These results demonstrate that Sim1 is essential for proper migration and the guidance of commissural axons of the spinal V3 INs.
