Identificación de variedades de arroz (Oryza sativa L.) cultivadas en Argentina mediante marcadores bioquímicos: su utilidad potencial para el registro de cultivares; Identification of rice varieties (Oryza sativa L.) cultivated in Argentina using biochemical markers: their potential utility for the registration of cultivars Medina, Ricardo Daniel; Faloci, Mirta Mabel; Marassi, Maria Antonia; Mroginski, Luis Amado Cuarenta y cinco variedades de arroz cultivadas en Argentina fueron caracterizadas por electroforesis de isoenzimas, utilizando geles discontinuos de poliacrilamida no desnaturalizantes (PAGE). Los sistemas isoenzimáticos analizados fueron: Fosfatasa ácida (ACP), Diaforasa (DIA), Esterasas (EST), Malato deshidrogenasa (MDH) y Siquimato deshidrogenasa (SDH). El sistema SDH mostró la mayor variabilidad formando 21 grupos, mientras que MDH evidenció el menor polimorfismo generando sólo 9. La identificación de todas las variedades se logró evaluando los cinco sistemas. Ello muestra que los marcadores bioquímicos pueden constituir un complemento o una alternativa a ser utilizada para caracterizar, identificar y registrar las variedades de arroz en Argentina.; Forty five rice varieties grown in Argentina were analyzed through isozyme analysis using discontinuous native polyacrylamide gels electrophoresis (PAGE). Polymorphic isozymes used to distinguish among the cultivars were: acid phosphatase (ACP), diaphorase (DIA), esterases (EST), malate dehydrogenase (MDH) and shikimate dehydrogenase (SDH). The SDH system showed the highest degree of variability in the banding patterns—21 groups were formed—compared to the MDH system which showed the least isozyme polymorphism—only 9 groups were formed. The tested varieties could be uniquely identified when all five isozyme were evaluated. These results show that biochemical markers could complement or be an alternative method of characterization, identification and registration for rice varieties in Argentina.

Efecto citotóxico de la toxina Shiga tipo 2 y su subunidad B en células epiteliales tubulares renales humanas en cultivo; Cytotoxic effect of Shiga toxin type 2 and its B subunit on human renal tubular epithelial cell cultures Pistone Creydt, Virginia; Nuñez, Pablo; Zotta, Elsa; Ibarra, Cristina Adriana Escherichia coli enterohemorrágica productora de toxina Shiga (Stx) causa diarrea acuosa, colitis hemorrágica y síndrome urémico hemolítico (SUH). En Argentina, el SUH es la principal causa de insuficiencia renal en niños. El objetivo de este trabajo fue estudiar la toxicidad de Stx tipo 2 (Stx2) y su subunidad B (Stx2B) en células epiteliales tubulares renales humanas (CERH), en presencia y ausencia de factores inflamatorios. Los efectos citotóxicos se evaluaron como alteración de la funcionalidad del epitelio; daños histológicos; viabilidad celular; síntesis de proteínas y apoptosis celular. Los resultados muestran que Stx2 regula el pasaje de agua a través de CERH a tiempos menores de 1h de incubación. A tiempos mayores, hasta 72 hs, el estudio de la morfología, la viabilidad, la síntesis de proteínas y la apoptosis demostró que las CERH fueron sensibles a la acción citotóxica de Stx2 y Stx2B de una manera dosis y tiempo dependiente. Estos efectos fueron potenciados por lipopolisacáridos bacterianos (LPS), IL-1<=, y butirato.; Shiga toxin (Stx)-producing E.coli causing watery diarrhea, hemorrhagic colitis and hemolytic-uremic syndrome (HUS). In Argentina, HUS is the most common cause of acute renal failure in children. The purpose of the present study was to examine the cytotoxicity of Stx type 2 (Stx2) and its B subunit (Stx2B) on human renal tubular epithelial cells (HRTEC), in the presence and absence of inflammatory factors. Cytotoxic effects were assessed in terms of functionality of the epithelium, histological damage, cell viability, protein synthesis and cellular apoptosis. Results show that Stx2 regulates the passage of water through the HRTEC within an incubation period of 1h. Within longer periods, up to 72 hours, the study of morphology, viability, protein synthesis and apoptosis shows that HRTEC were sensitive to the cytotoxic action of Stx2 and Stx2B in a doseand time-dependent manner. These effects were potentiated by lipopolysaccharides (LPS), IL-1β, and butirate.

¿Podemos estimar el impacto de las transformaciones del paisaje sobre la ecodiversidad? Neiff, Juan Jose; Rolón, Marcelo; Casco, Sylvina Lorena Se han propuesto distintos criterios para medir la diversidad a nivel local (alfa y beta diversidad) a nivel regional (gama diversidad) y también a nivel del paisaje (ecodiversidad). De todas estas aproximaciones a la complejidad biótica en los ecosistemas, la ecodiversidad permite conocer la disponibilidad y la conectividad entre hábitat y lograr una idea de la variabilidad espacial de los ecosistemas. Se presentan siete índices de ecodiversidad y se discute sus ventajas y desventajas para el análisis de paisajes muy disturbados. Se analizó el paisaje del Establecimiento Las Marías, en el NE de Corrientes, que tiene algo más de 30.000 ha, comprendiendo 12.000 ha de sistemas forestales nativos y cultivados y 18.000 ha. dedicadas a té, yerba mate y policultivos. Se utilizó imágenes Landsat 7 y el procedimiento de Ecological Land Classification (ELC), para identificar las principales unidades de paisaje (bosques, pasturas, cuerpos de agua, diferentes cultivos). Se encontraron tres subsistemas de paisaje diferentes, se obtuvo información del número de polígonos y de la superficie comprendida en cada uso del paisaje y se la comparó cuantitativamente mediante varios índices. Se concluye que una determinada unidad de paisaje puede tener muy diferente diversidad, según el contexto de paisaje en el que se encuentre incluida.; Different approaches to measure the diversity at local level (alpha and beta diversity), at regional level (gamma-diversity) and also at the landscape level (ecodiversity, in sense of Naveh) have been proposed. Of all these approaches, the ecodiversity allows to know the habitat availability, the connectivity among habitat and to achieve an idea of the space variability of the ecosystems. Seven indexes of ecodiversity were tested and discusses their advantages and disadvantages for the analysis in a very disturbed area in the northeast of Corrientes. The results are presented for Las Marías Company that has something more than 30,000 hectares of those which 12,000 hectares are occupied with native and cultivated forest and 18,000 ha are devoted to tea, yerba mate, to the livestock breeding and aromatic plants. It were used satelital images Landsat 7 analyzed with ARC View 3.2 and the procedure of Ecological Land Classification (ELC) to identify the main landscape units (forests, grasslands, water bodies). With this information three different subsystems of landscape were identified. The ecodiversity indexes were used to compare the ecodiversity patterns with the biotic complexity. We concludes that a certain landscape unit should be very different in specific diversity, according to the landscape context in which is included.

Telemicroscopía: acceso remoto a microscopios de alta perfomance Capani, Francisco; Rey Funes, Manuel; Coirini, Hector Dos grupos de investigadores, uno en Buenos Aires, Argentina, dirigido por Héctor Coirini, y el otro en San Diego, Califonia, EEUU, dirigido por Mark Ellisman, han usado de manera exitosa INTERNET 2, una autopista informática de alta capacidad, para unir una computadora localizada en el Departamento de Bioquímica Humana de la Facultad de Medicina de la Universidad de Buenos Aires a un microscopio de voltaje intermedio situado en el Instituto Nacional de Investigación en Microscopía e Imágenes en EEUU. Esta colaboración a larga distancia (10.000km) marca un hito en el avance de la ciencia en Latinoamérica. Científicos de la Argentina ahora tienen acceso a instrumentos especializados y pueden realizar sus investigaciones sin pérdida de tiempo y sin necesidad de invertir dinero y tiempo en viajes. Además, la interfase de uso de este instrumento en forma remota permite la colaboración con otros expertos lo cual facilita y mejora la calidad de los resultados obtenidos.

Evidence of the presence of calcium/calmodulin-dependent protein kinase IV in human sperm and its involvement in motility regulation Marin Briggiler, Clara Isabel; Jha, Kula N.; Chertihin, Olga; Buffone, Mariano Gabriel; Herr, John C,; Vazquez, Monica Hebe; Visconti, Pablo E. The mechanisms involved in the regulation of mammalian sperm motility are not well understood. Calcium ions (Ca(2+)) have been suggested to play a key role in the maintenance of motility; nevertheless, how Ca(2+) modulates this process has not yet been completely characterized. Ca(2+) can bind to calmodulin and this complex regulates the activity of multiple enzymes, including Ca(2+)/calmodulin-dependent protein kinases (CaM kinases). Results from this study confirmed that the presence of Ca(2+) in the incubation medium is essential for maintaining human sperm motility. The involvement of CaM kinases in Ca(2+) regulation of human sperm motility was evaluated using specific inhibitors (KN62 and KN93) or their inactive analogues (KN04 and KN92 respectively). Sperm incubation in the presence of KN62 or KN93 led to a progressive decrease in the percentage of motile cells; in particular, incubation with KN62 also reduced sperm motility parameters. These inhibitors did not alter sperm viability, protein tyrosine phosphorylation or the follicular fluid-induced acrosome reaction; however, KN62 decreased the total amount of ATP in human sperm. Immunological studies showed that Ca(2+)/calmodulin-dependent protein kinase IV (CaMKIV) is present and localizes to the human sperm flagellum. Moreover, CaMKIV activity increases during capacitation and is inhibited in the presence of KN62. This report is the first to demonstrate the presence of CaMKIV in mammalian sperm and suggests the involvement of this kinase in the regulation of human sperm motility.

Endothelin isoforms and the response to myocardial stretch Ennis, Irene Lucia; Garciarena, Carolina Denis; Perez, Nestor Gustavo; Dulce, Raul; Camilion, Maria Cristina; Cingolani, Horacio Eugenio Myocardial stretch elicits a biphasic increase in developed force with a first rapid force response and a second slow force response (SFR). The rapid phase is due to an increase in myofilament Ca(2+) responsiveness; the SFR, analyzed here, is ascribed to a progressive increase in Ca(2+) transients. Experiments were performed in cat papillary muscles to further elucidate the signaling pathway underlying the SFR. Although the SFR was diminished by BQ-123, a similar endothelin (ET)-1-induced increase in force was not affected: 23 +/- 2 vs. 23 +/- 3% (not significant). Instead, BQ-123 suppressed the contractile effects of ET-2 or ET-3 (21 +/- 2 and 25 +/- 3% vs. -1 +/- 1 and -7 +/- 3% respectively, P < 0.05), suggesting that ET-2 or ET-3, but not ET-1, was involved in the SFR. Each isoform activated the Na(+)/H(+) exchanger (NHE-1), increasing intracellular Na(+) concentration by 2.0 +/- 0.1, 2.3 +/- 0.1, and 2.1 +/- 0.4 mmol/l for ET-1, ET-2, and ET-3, respectively (P < 0.05). The NHE-1 inhibitor HOE-642 prevented the increases in force and intracellular Na(+) concentration induced by all the ET isoforms, but only ET-2 and ET-3 effects were sensitive to BQ-123. Real-time RT-PCR measurements of prepro-ET-1, -ET-2, and -ET-3 were performed before and 5, 15, and 30 min after stretch. No changes in ET-1 or ET-2, but an increase of approximately 60% in ET-3, mRNA after 15 min of stretch were detected. Stretch-induced ET-3 mRNA upregulation and its mechanical counterpart were suppressed by AT(1) receptor blockade with losartan. These data suggest a role for AT(1)-mediated ET-3 released in the early activation of NHE-1 that follows myocardial stretch.

Identifying variable gamma-ray sources through radio observations Paredes, Josep Maria; Martí, Josep; Torres, Diego F.; Romero, Gustavo Esteban; Combi, Jorge Ariel; Bosch Ramon, Valentí; García Sánchez, J. We present preliminary results of a campaign undertaken with different radio interferometers to observe a sample of the most variable unidentified EGRET sources. We expect to detect which of the possible counterparts of the γ -ray sources (any of the radio emitters in the field) varies in time with similar timescales as the γ -ray variation. If the γ -rays are produced in a jet-like source, as we have modelled theoretically, synchrotron emission is also expected at radio wavelengths. Such radio emission should appear variable in time and correlated with the γ -ray variability.

Galectin-1 as a potential cancer target Rabinovich, Gabriel Adrián Galectins are a family of structurally related carbohydrate-binding proteins, which are defined by their affinity for poly-N-acetyllactosamine-enriched glycoconjugates and sequence similarities in the carbohydrate recognition domain. Galectin-1, a member of this family, contributes to different events associated with cancer biology, including tumour transformation, cell cycle regulation, apoptosis, cell adhesion, migration and inflammation. In addition, recent evidence indicates that galectin-1 contributes to tumour evasion of immune responses. Given the increased interest of tumour biologists and clinical oncologists in this field and the potential use of galectins as novel targets for anticancer drugs, we summarise here recent advances about the role of galectin-1 in different events of tumour growth and metastasis.

Histological events during in vitro rooting of Nothofagus nervosa (Fagaceae) Martínez Pastur, Guillermo José; Arena, Miriam Elisabet; Hernandez, Luis Francisco; Curvetto, Nestor Raul; Eliasco, Eleonora In vitro rooting protocols were previously performed on Nothofagus nervosa to optimise the culture medium and environmental conditions. A qualitative and quantitative tissue differentiation study during adventitious rooting in N. nervosa under different light/dark conditions was carried out to increase knowledge of the rhizogenesis process in shoots. The histological events through the rooting period were consistent with the proposed biochemical markers (peroxidases, tissue nutrient contents, polyamines, flavonoids). Development of parenchymatic tissues, shown by the staining pattern of the cell contents, and cambium activity were the best tissues to define the rooting phases. Knowledge of the histological changes could be used to optimise a protocol for micro‐propagation improving timing, quantity, and quality of roots, which would positively affect the survival rate during hardening.

GABAB1 knock-out mice reveals alteration in prolactin levels, gonadotropin axis and reproductive function Catalano, Paolo Nicolás; Bonaventura, Maria Marta; Silveyra, Patricia; Bettler, Bernhard; Libertun, Carlos; Lux, Victoria Adela R. gamma-Aminobutyric acid (GABA) has been implicated in the control of hypophyseal functions. We evaluated whether the constitutive loss of functional GABA(B) receptors in GABA(B1) knockout (GABA(B1)(-/-)) mice alters hormonal levels, under basal and stimulated conditions, and reproductive function. The serum hormone levels were measured by radioimmunoassay, the estrous cyclicity was evaluated by vaginal lavages, and the mating behavior was determined by the presence of vaginal plugs. A moderate hyperprolactinemic condition was observed, in which prolactin increase and thyroid-stimulating hormone decrease were similar between genotypes. Basal luteinizing hormone (LH), follicle-stimulating hormone, thyroid-stimulating hormone, and growth hormone levels were similar between genotypes in each sex. Analysis of the gonadotropin axis revealed no differences in puberty onset between female genotypes. In con trast, the estrous cyclicity was significantly disrupted in GABA(B1)(-/-) female mice, showing significantly extended periods in estrus and shortened periods in proestrus. Reproduction was significantly compromised in GABA(B1)(-/-) females, with a significantly lower proportion of mice (37.5%) getting pregnant during the first 30 days of mating as compared with wild-type controls (87.5%). Moreover, only 14% of vaginal plug positive GABA(B1)(-/-) females had successful pregnancies as compared with 75% in the controls. In addition, the postovariectomy LH rise was significantly advanced in GABA(B1)(-/-) mice, while the response to estradiol feedback was similar in both genotypes. In conclusion, our endocrine analysis of GABA(B1)(-/-) mice reveals that GABA(B) receptors are involved in the regulation of basal prolactin titers. Moreover, the hypothalamic-hypophyseal-ovarian axis is seriously disturbed, with alterations in cyclicity, postcastration LH increase, and fertility indexes. The molecular mechanism underlying these hormonal disturbances remains to be addressed.

Design of photocatalytic reactors made easy by considering the photons as immaterial reactants Camera Roda, Giovanni; Santarelli, Francesco; Martin, Carlos Alberto While it is quite obvious that photons have an essential role in photochemical and photocatalytic processes, it is not simple to analyse the radiation process. A simple approach is presented on the assumption that photons can be treated as immaterial reactants. It is then possible to evaluate the radiation process in terms of parameters such as conversion, selectivity and yield, which are common in the conventional reaction engineering, and of an additional parameter, a volume efficiency factor, which accounts for the exploitation of the reaction volume as the result of the inevitable attenuation of the radiation in the transport through the participating medium. Attention has also been focused on the validation of kinetic data when, as it is usually done, they are interpreted in terms of volume averages. Finally, guidelines have been prepared to support preliminary phases of analysis and/or design of a photocatalytic reactor.

Linear combination of atomic orbitals calculation of the Auger neutralization rate of He on Al (111), Al (100) and Al (110) surfaces Valdés, Diego; Goldberg, Edith Catalina; Blanco, J. M.; Monreal, R. C. We develop a theory of the Auger neutralization rate of ions on solid surfaces in which the matrix elements for the transition are calculated by means of a linear combination of atomic orbitals technique. We apply the theory to the calculation of the Auger rate of He+ on unreconstructed Al(111), (100), and (110) surfaces, assuming He+ to approach these surfaces on high symmetry positions and compare them with the results of the jellium model. Although there are substantial differences between the Auger rates calculated with both kinds of approaches, those differences tend to compensate when evaluating the integral along the ion trajectory and, consequently, are of minor influence in some physical magnitudes like the ion survival probability for perpendicular energies larger than 100 eV. We find that many atoms contribute to the Auger process and small effects of lateral corrugation are registered.

Diffuse component spectra of solar active regions at submillimeter wavelengths Silva, Adriana V. R.; Laganá, Tatiana F.; Castro, C. Guillermo Gimenez de; Kaufmann, Pierre; Costa, Joaquim E. R.; Levato, H.; Rovira, Marta Graciela Solar maps at 212 and 405 GHz obtained by the Solar Submillimetric Telescope (SST) show regions of enhanced brightness temperature, which coincide with the location of active regions. A statistical study of the radio emission from these active regions was performed for the first time at such high frequencies during 23 days on June and July 2002, when the atmospheric opacity was low. The brightest regions on the maps were chosen for this study, where the brightness excess observed varies from 3 to 20% above quiet Sun levels (i.e., 200–1000 K) at both wavelengths. Sizes of the regions of enhanced emission calculated at half the maximum value were estimated to be between 2′ and 7′. These sizes agree with observed sizes of active regions at other wavelengths such as Hα and ultraviolet. An important result is that the flux density spectra of all sources increase toward submillimeter frequencies, yielding flux density spectral index with an average value of 2.0. The flux density of the active region sources were complemented with that from maps at 17 and 34 GHz from the Nobeyama Radio Heliograph. The resulting spectra at all four frequencies were fit considering the flux density to be due to thermal bremsstrahlung from the active region. In the calculations, the source radius was assumed to be the mean of the measured values at 212 and 405 K. The effective temperatures of the radio emitting source, assumed homogeneous, obtained from this fit were 0.6–2.9 × 104 K, for source diameters of 2′–7′.

Self-induced decoherence and the classical limit of quantum mechanics Castagnino, Mario Alberto G. J.; Lombardi, Olimpia Iris In this paper we argue that the emergence of the classical world from the underlying quantum reality involves two elements: self‐induced decoherence and macroscopicity. Self‐induced decoherence does not require the openness of the system and its interaction with the environment: a single closed system can decohere when its Hamiltonian has continuous spectrum. We show that, if the system is macroscopic enough, after self‐induced decoherence it can be described as an ensemble of classical distributions weighted by their corresponding probabilities. We also argue that classicality is an emergent property that arises when the behavior of the system is described from an observational perspective.

Angular dispersion of protons passing through thin metallic films Archubi, Claudio Darío; Denton, C.; Eckardt, J. C.; Lantschner, G. H.; Arista, N. R.; Valdés, J.; Ferrón, J. The angular distributions of protons after traversing thin polycrystalline Al targets (∼15 nm) with an incident energy of 10 keV have been measured and an analysis of the targets by means of transmission electron microscopy (TEM) techniques has been made. The separate influence of the different crystal characteristics and defects has been evaluated by numerical simulation considering the interaction of the ion with all the nearest neighboring atoms simultaneously. In the analysis we included the evaluation of the effects of lattice vibrations, oxide layers and foil roughness on the angular distributions. Previous experimental data in monocrystalline and polycrystalline Au targets has also been analyzed. For a consistency check a comparison with the results of the MARLOWE code for the simpler case of proton channeling in 〈1 0 0〉 Al has been performed. As in the case of Au, the present results indicate that the experiments can be explained in terms of a modified Moliere potential, and confirm the critical influence of crystal characteristics, in this case the amorphous oxide layer on the surface and the thermal vibration of the lattice atoms.

Galectin-1 sensitizes resting human T lymphocytes to Fas (CD95)-mediated cell death via mitochondrial hyperpolarization, budding, and fission. Matarrese, Paola; Tinari, Antonella; Mormone, Elisabetta; Bianco, German Ariel; Toscano, Marta Alicia; Ascione, Barbara; Rabinovich, Gabriel Adrián; Malorni, Walter Galectins have emerged as a novel family of immunoregulatory proteins implicated in T cell homeostasis. Recent studies showed that galectin-1 (Gal-1) plays a key role in tumor-immune escape by killing antitumor effector T cells. Here we found that Gal-1 sensitizes human resting T cells to Fas (CD95)/caspase-8-mediated cell death. Furthermore, this protein triggers an apoptotic program involving an increase of mitochondrial membrane potential and participation of the ceramide pathway. In addition, Gal-1 induces mitochondrial coalescence, budding, and fission accompanied by an increase and/or redistribution of fission-associated molecules h-Fis and DRP-1. Importantly, these changes are detected in both resting and activated human T cells, suggesting that Gal-1-induced cell death might become an excellent model to analyze the morphogenetic changes of mitochondria during the execution of cell death. This is the first association among Gal-1, Fas/Fas ligand-mediated cell death, and the mitochondrial pathway, providing a rational basis for the immunoregulatory properties of Gal-1 in experimental models of chronic inflammation and cancer.

El agua en la Produccion de cultivos extensivos: III. Impacto de las practicas de manejo sobre la eficiencia de uso del agua Micucci, Federico; Alvarez, Carina Rosa El agua es el factor más limitante en la producción de cultivos extensivos en secano en la región pampeana argentina y en muchas otras regiones del mundo. Por lo tanto, debemos saber producir haciendo un uso eficiente del recurso más escaso, el agua. El objetivo de este artículo es brindar algunos conceptos básicos relacionados con la eficiencia de uso del agua (EUA) y las prácticas de manejo que la mejoran. Para ello es necesario conocer cuales son los componentes de la EUA posibles de modificar y como las prácticas agronómicas pueden afectarla.

Sunflower chlorotic mottle virus in compatible interactions with sunflower: ROS generation and antioxidant response Arias, Maria Cecilia; Luna, Celina Mercedes; Rodríguez, Marianela; Lenardon, Sergio Luis; Taleisnik, Edith Sunflower chlorotic mottle virus (SuCMoV) is a recently described potyvirus that causes systemic infections in sunflower plants leading to chlorotic mottling and important growth reductions and yield losses. Oxidative damage is expressed after symptom development in this host-pathogen combination. The involvement of antioxidant enzyme activities in disease susceptibility was studied in two sunflower lines differing in the intensity and rate of development of SuCMoV infections: L2 is more susceptible than L33. A transient superoxide production peak was detected in leaves of both lines before symptom development. H2O2 accumulation increased before symptom expression in infected plants of L33 but in L2 such increase was registered only after symptoms became evident. In healthy plants of both lines, superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) showed similar activity levels. In inoculated plants of line L2, but not in L33, SOD and CAT activities increased significantly before the appearance of symptoms, and APX increases were detected later. A 1 mM SA treatment effectively decreased SuCMoV accumulation in plants of L2 but it did not affect it in L33. This treatment increased H2O2 accumulation and prevented the increase in antioxidant enzyme activities in infected plants of L2. It is suggested that increases in antioxidant enzyme activities interrupted the signals generated by the increase in ROS, which may have otherwise triggered defence reactions in the host and thus, resulted in a compatible interaction.

Scanning electron microscopy of Chordodes moutoni Camerano, 1895 (Gordiida, Nematomorpha) Zanca, Fernanda Mariel; De Villalobos, Cristina Taxonomic characters of both male and female horse-hair worms Chordodes moutoni Camerano, 1895 (Nematomorpha) are re-described using scanning electron microscopy. The features are compared with the original description. C. moutoni cuticle has five different areolar types in male while female have six types of areoles. The crowned areoles, characteristic of Chordodes, are surrounded by other areoles forming pairs or clusters. Sexual dimorphism was found in the cuticular pattern, the female showing two different types of crowned areoles with distinct distribution pattern while the male has only one type of crowned areoles. These data are compared to other Chordodes species that have been studied.

Neuronal differentiation in the adult hippocampus recapitulates embryonic development Esposito, Maria Soledad; Piatti, Veronica del Carmen; Laplagne, Diego Andres; Morgenstern, Nicolás Andrés; Ferrari, Carina Cintia; Pitossi, Fernando Juan; Schinder, Alejandro Fabián In the adult hippocampus and olfactory bulb, neural progenitor cells generate neurons that functionally integrate into the existing circuits. To understand how neuronal differentiation occurs in the adult hippocampus, we labeled dividing progenitor cells with a retrovirus expressing green fluorescent protein and studied the morphological and functional properties of their neuronal progeny over the following weeks. During the first week neurons had an irregular shape and immature spikes and were synaptically silent. Slow GABAergic synaptic inputs first appeared during the second week, when neurons exhibited spineless dendrites and migrated into the granule cell layer. In contrast, glutamatergic afferents were detected by the fourth week in neurons displaying mature excitability and morphology. Interestingly, fast GABAergic responses were the latest to appear. It is striking that neuronal maturation in the adult hippocampus follows a precise sequence of connectivity (silent → slow GABA → glutamate → fast GABA) that resembles hippocampal development. We conclude that, unlike what is observed in the olfactory bulb, the hippocampus maintains the same developmental rules for neuronal integration through adulthood.