Las repercusiones de la política peronista hacia América Latina luego del golpe de estado (1955-1958).

El presente proyecto se propone investigar las reacciones que despertó la política de difusión del modelo peronista en América latina, fenómeno que adquirió mayor visibilidad inmediatamente durante el gobierno de facto que lo derrocó en 1955 y cuya gestión finalizó en 1958. Al respecto, la tarea de propaganda sumó a la capacidad de Perón para comunicarse con públicos masivos, la utilización de diferentes técnicas y la creación de organismos para propagar su modelo de conducción política en América Latina, durante la gestión 1946-1955. En tal sentido, numerosos discursos y prácticas fueron también entendidos como un modo de volver imprecisos los contornos de los espacios nacionales en la región. La recepción de esta política regional despertó posiciones antinómicas, que luego del golpe de estado de 1955, salieron más claramente a la superficie. Así, entre 1955 y 1958 tuvieron una influencia significativa en: los intentos de Perón por mantener su liderazgo a la distancia, las vinculaciones que entabló con diversos representantes de las dirigencias políticas continentales, la acción de los grupos peronistas dispersos en el Latinoamérica y la actitud ante las presiones ejercidas por gobierno de facto. Entretanto, para Perón el problema que significaba asegurarse la efectiva conducción del movimiento, sin su presencia física, era un tema prioritario y para lograrlo utilizó diversas estrategias. Este tema ha sido estudiado exhaustivamente por diversos autores para el caso argentino, no obstante son escasos y dispersos los estudios relativos a Latinoamérica. Si bien, existen algunos intentos de ordenar correspondencia y otros testimonios, todavía no se ha logrado reunir en un corpus sistemático las variadas fuentes, cuyas evidencias se encuentran sumamente fragmentadas y son de difícil acceso por sus condiciones de producción En definitiva, por ahora cada hallazgo constituye un indicio que nos orienta hacia posteriores exploraciones y permite visualizar su proyección posterior. En este contexto, nuestra hipótesis es que luego el golpe de 1955, los grupos proclives y opositores a la política regional del presiente derrocado constituyeron actores importantes en la posible comunicación con los grupos partidarios diseminados en América Latina, la intermediación con el movimiento en Argentina y la reconstrucción de la imagen del líder exilado, todo ello obstaculizado por la el proceso de desperonización, encarado por la Revolución Libertadora.

Neohilgertia venusti Gen. N. SP. N. (Nematoda: Oxyuridae)from Thylamys venustus cinderellus (Thomas) Reig, Kirsch & Marshall, 1985 (Marsupialia: Didelphidae) in Burruyacu, Tucuman, Argentina - Systematic position and possible evolution

Neohilgertia gen. n. proposed for Oxyuridae nematodes from Thylamys venustus cinderellus (Marsupialia: Didelphidae) is described. The hypothesis about the possibility of a secondary parasitism for marsupials and the origin of the genus in the African Sciuridae parasite ancestors is discussed.

Pterigodermatites (Paucipectines) spinicaudatis n.sp. (Nematoda: Rictularidae) from Dromiciops australis (Marsupialia: Microbiotheriidae) in Bariloche, Rio Negro, Argentina, biogeographical distribution and host-parasite relationships

Pterigodermatites (P.) spinicaudatis sp.n. from Dromiciops australis is proposed and described. The simple morphology of the ovijector and the presence of a well developed spine between the two cuticular projections at the caudal extremity of the female distinguish the studied nematode from the remainder species of the genus parasitizing South American Edentata, marsupials and cricetid rodents. The distribution area of the hosts of the different species of P. (P.) are given. The studied genus does not parasitize any Australian marsupials. It was found in the endemic South American Microbiotheriidae. This fact suggests from a parasitological point of view that D. australis is not related to the Australian marsupials but to the South American ones.

Cotrimoxazole enhances the in vitro susceptibility of Coccidioides posadasii to antifungals

The aim of the present study was to evaluate the effect of cotrimoxazole on the in vitro susceptibility of Coccidioides posadasii strains to antifungals. A total of 18 strains of C. posadasii isolated in Brazil were evaluated in this study. The assays were performed in accordance with the Clinical and Laboratory Standards Institute guidelines and the combinations were tested using the checkerboard method. The minimum inhibitory concentrations were reduced by 11, 2.4, 4.3 and 3.5 times for amphotericin B, itraconazole, fluconazole and voriconazole, respectively. Moreover, it was seen that cotrimoxazole itself inhibited C. posadasii strains in vitro. The impairment of folic acid synthesis may be a potential antifungal target for C. posadasii.

Distribución e indices de avistamientos de mamiferos marinos y su relación con la abundancia del Krill Euphasia Superba. Perú Antar IX

Un total de 41 avistamientos de mamíferos marinos se registraron en el Estrecho de Bransfield y alrededores de la Isla Elefante entre los 60,5° y 63° S y los 53,5 y 60° W, cubriendo 853,02 mn durante el Crucero de Evaluación de la Biomasa del Krill en la IX Expedición Peruana a la Antártida, desarrollada entre el 12 y 24 de enero de 1998. Dentro del orden Cetacea se registraron 33 ballenas jorobadas Megaptera novaeangliae, 2 ballenas minke Balaenoptera bonaerenses, 9 orcas Orcinus orca, 2 balaenoptéridos y un cetáceo mayor no identificado. Entre los registros del orden Pinnipedia figuran 21 lobos finos antárticos Arctocephalus gazella, 2 focas cangrejas Lobodon carcinophagus y una foca leopardo Hidrurga leptonix. La presencia de estos mamíferos marinos en las áreas con valores altos en la biomasa de krill, hace presumir que estarían cumpliendo actividades tróficas, constituyéndose en posibles indicadores de la existencia de concentraciones de este crustáceo en la región antártica.

Wnt-3a and Wnt-3 differently stimulate proliferation and neurogenesis of spinal neural precursors and promote neurite outgrowth by canonical signaling

Wnt factors regulate neural stem cell development and neuronal connectivity. Here we investigated whether Wnt-3a and Wnt-3, expressed in the developing spinal cord, regulate proliferation and the neuronal differentiation of spinal cord neural precursors (SCNP). Wnt-3a promoted a sustained increase of SCNP proliferation, whereas Wnt-3 enhanced SCNP proliferation transiently and increased neurogenesis through β-catenin signaling. Consistent with this, Wnt-3a and Wnt-3 differently regulate the expression of Cyclin-dependent kinase inhibitors. Furthermore, Wnt-3a and Wnt-3 stimulated neurite outgrowth in SCNP-derived neurons through ß-catenin and TCF4-dependent transcription. GSK-3ß inhibitors mimicked Wnt signaling and promoted neurite outgrowth in established cultures. We conclude that Wnt-3a and Wnt-3 signal through the canonical Wnt/β-catenin pathway to regulate different aspects of SCNP development. These findings may be of therapeutic interest for the treatment of neurodegenerative diseases and nerve injury.

Signalling by neurotrophins and hepatocyte growth factor regulates axon morphogenesis by differential β-catenin phosphorylation

Tyrosine phosphorylation of ß-catenin, a component of adhesion complexes and the Wnt pathway, affects cell adhesion, migration and gene transcription. By reducing ßcatenin availability using shRNA-mediated gene silencing or expression of intracellular N-cadherin, we show that ß-catenin is required for axon growth downstream of Brain Derived Neurotrophic Factor (BDNF) and Hepatocyte Growth Factor (HGF) signalling. We demonstrate that receptor tyrosine kinases (RTK) Trk and Met interact with and phosphorylate ß-catenin. Neurotrophins (NT) stimulation of Trk receptors results in phosphorylation of ß-catenin at residue Y654 and increased axon growth and branching. Conversely, pharmacological inhibition of Trk or a Y654F mutant blocks these effects. ß-catenin phospho(P)-Y654 colocalizes with the cytoskeleton at growth cones. However, HGF that also increases axon growth and branching, induces ß-catenin phosphorylation at Y142 and a nuclear localization. Interestingly, dominant negative ΔN-TCF4 abolishes the effects of HGF in axon growth and branching, but not of NT. We conclude that NT and HGF signalling differentially phosphorylate ß-catenin, targeting ß-catenin to distinct compartments to regulate axon morphogenesis by TCF4-transcription-dependent and independent mechanisms. These results place ß-catenin downstream of growth factor/RTK signalling in axon differentiation.

Chemokines induce axon outgrowth downstream of Hepatocyte Growth Factor and TCF/β-catenin signaling

Axon morphogenesis is a complex process regulated by a variety of secreted molecules, including morphogens and growth factors, resulting in the establishment of the neuronal circuitry. Our previous work demonstrated that growth factors [Neurotrophins (NT) and Hepatocyte Growth Factor (HGF)] signal through β-catenin during axon morphogenesis. HGF signaling promotes axon outgrowth and branching by inducing β-catenin phosphorylation at Y142 and transcriptional regulation of T-Cell Factor (TCF) target genes. Here, we asked which genes are regulated by HGF signaling during axon morphogenesis. An array screening indicated that HGF signaling elevates the expression of chemokines of the CC and CXC families. In line with this, CCL7, CCL20, and CXCL2 significantly increase axon outgrowth in hippocampal neurons. Experiments using blocking antibodies and chemokine receptor antagonists demonstrate that chemokines act downstream of HGF signaling during axon morphogenesis. In addition, qPCR data demonstrates that CXCL2 and CCL5 expression is stimulated by HGF through Met/b-catenin/TCF pathway. These results identify CC family members and CXCL2 chemokines as novel regulators of axon morphogenesis downstream of HGF signaling.

Preparation of penta-azole containing cyclopeptides: challenges in macrocyclization

Herein is described the synthesis of several analogs of the natural product IB-01211 from concatenated azoles, via a biomimetic pathway based on cyclization-oxidation of serine containing peptides combined with the Hantzsch synthesis. The macrocyclization of rigid peptide compounds 1 and 2 to give IB-01211 and its epimer 12b was explored, and the results are compared here to those previously obtained for the macrocyclization of more flexible structures in the syntheses of YM-216391, telomestatin, and IB-01211. Lastly, the preliminary results of anti-tumor activity screening of the synthesized analogs are discussed.

Synthesis and antitumor activity of mechercharmycin A analogues

Several analogs of the cytotoxic thiopeptide IB-01211 or Mechercharmycin A (1) have been synthetized. The cytotoxicity of 1 and the synthetized analogs was evaluated against a panel of three human tumor cell lines. Thiopeptide 1 and the most active derivatives, 2 and 3c, were chosen for further studies like effects on cell cycle progression and induction of apoptosis. Interestingly, the inhibition of cell division and activation of a programmed cell death by apoptosis was detected.

Erratum: Global pressures, specific responses: effects of nutrient enrichment in streams from different biomes

We assessed the effects of nutrient enrichment on three stream ecosystems running through distinct biomes (Mediterranean, Pampean and Andean). We increased the concentrations of N and P in the stream water 1.6–4-fold following a before–after control–impact paired series (BACIPS) design in each stream, and evaluated changes in the biomass of bacteria, primary producers, invertebrates and fish in the enriched (E) versus control (C) reaches after nutrient addition through a predictive-BACIPS approach. The treatment produced variable biomass responses (2–77% of explained variance) among biological communities and streams. The greatest biomass response was observed for algae in the Andean stream (77% of the variance), although fish also showed important biomass responses (about 9–48%). The strongest biomass response to enrichment (77% in all biological compartments) was found in the Andean stream. The magnitude and seasonality of biomass responses to enrichment were highly site specific, often depending on the basal nutrient concentration and on windows of ecological opportunity (periods when environmental constraints other than nutrients do not limit biomass growth). The Pampean stream, with high basal nutrient concentrations, showed a weak response to enrichment (except for invertebrates), whereas the greater responses of Andean stream communities were presumably favored by wider windows of ecological opportunity in comparison to those from the Mediterranean stream. Despite variation among sites, enrichment globally stimulated the algal-based food webs (algae and invertebrate grazers) but not the detritus-based food webs (bacteria and invertebrate shredders). This study shows that nutrient enrichment tends to globally enhance the biomass of stream biological assemblages, but that its magnitude and extent within the food web are complex and are strongly determined by environmental factors and ecosystem structure

Global pressures, specific responses: effects of nutrient enrichment in streams from different biomes

We assessed the effects of nutrient enrichment on three stream ecosystems running through distinct biomes (Mediterranean, Pampean and Andean). We increased the concentrations of N and P in the stream water 1.6–4-fold following a before–after control–impact paired series (BACIPS) design in each stream, and evaluated changes in the biomass of bacteria, primary producers, invertebrates and fish in the enriched (E) versus control (C) reaches after nutrient addition through a predictive-BACIPS approach. The treatment produced variable biomass responses (2–77% of explained variance) among biological communities and streams. The greatest biomass response was observed for algae in the Andean stream (77% of the variance), although fish also showed important biomass responses (about 9–48%). The strongest biomass response to enrichment (77% in all biological compartments) was found in the Andean stream. The magnitude and seasonality of biomass responses to enrichment were highly site specific, often depending on the basal nutrient concentration and on windows of ecological opportunity (periods when environmental constraints other than nutrients do not limit biomass growth). The Pampean stream, with high basal nutrient concentrations, showed a weak response to enrichment (except for invertebrates), whereas the greater responses of Andean stream communities were presumably favored by wider windows of ecological opportunity in comparison to those from the Mediterranean stream. Despite variation among sites, enrichment globally stimulated the algal-based food webs (algae and invertebrate grazers) but not the detritus-based food webs (bacteria and invertebrate shredders). This study shows that nutrient enrichment tends to globally enhance the biomass of stream biological assemblages, but that its magnitude and extent within the food web are complex and are strongly determined by environmental factors and ecosystem structure

Otimização de método para determinação de flavonóis e flavonas em frutas por cromatografia líquida de alta eficiência utilizando delineamento estatístico e análise de superfície de resposta

This work optimized the HPLC conditions for the simultaneous determination of luteolin, apigenin, myricetin, quercetin and kaempferol in aglycone form, as well defined the best conditions for hydrolysis/extraction of these flavonoids in fruits, using the statistical central composite design and response surface analysis. A reverse phase method was developed using a gradient of methanol/water acidified with 0.3% formic acid as mobile phase and a photodiode array detector. The samples were extracted with methanol/water (50:50 v/v) at 90 ºC. The optimum time and HCl concentration varied for the different fruits investigated, demonstrating the necessity of optimizing these conditions for each fruit analyzed. Good recovery (87.1 to 96.3%), repeatability and linearity were obtained.

Análises térmicas e processo de sinterização da cerâmica KSr2Nb5O15 dopada com CuO

KSr2Nb5O15 is a ferroelectric material. The sintering process of the KSr2Nb5O15 ceramic doped with different amounts of CuO was investigated in this research. It was found that CuO is effective as promoter of the densification process of the KSN ceramic. The developed microstructures were different due to the amount of CuO and secondary phases were observed in the microstructures. However, the results of X - ray diffraction showed that only the tetragonal tungsten bronze (TTB) structure was identified in all the investigated ceramic systems. The thermal behavior of CuO and also of the CuO - KSN phase mixture was investigated by thermal analysis.

Compostos orgânicos voláteis na defesa induzida das plantas contra insetos herbívoros

The identification and manipulation of chemical compounds involved in vital activities of arthropods have the potential for developing less aggressive pest control strategies. Herbivory induces the emission of volatile organic compounds involved in the recruitment of natural enemies, plant-plant interactions and repellency of other herbivores. In this report, we review the main chemical groups of volatile organic compounds and their ecological functions, provide an overview of the signal transduction pathways activated upon herbivory, and review the current state of knowledge for practical applications in pest management. We conclude by proposing perspectives for future research.