Presidencia Roque Saenz Pena, Argentina

National University of Buenos Aires Northeast Province

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McCarthy C.B.,National University of La Plata | McCarthy C.B.,National University of Buenos Aires Northeast Province | Santini M.,Administracion Nacional Of Laboratorios E Institutos Of Salud | Diambra L.A.,National University of La Plata
PLoS ONE | Year: 2013

Leishmaniasis is a vector-borne disease with a complex epidemiology and ecology. Visceral leishmaniasis (VL) is its most severe clinical form as it results in death if not treated. In Latin America VL is caused by the protist parasite Leishmania infantum (syn. chagasi) and transmitted by Lutzomyia longipalpis. This phlebotomine sand fly is only found in the New World, from Mexico to Argentina. However, due to deforestation, migration and urbanisation, among others, VL in Latin America is undergoing an evident geographic expansion as well as dramatic changes in its transmission patterns. In this context, the first VL outbreak was recently reported in Argentina, which has already caused 7 deaths and 83 reported cases. Insect vector transcriptomic analyses enable the identification of molecules involved in the insect's biology and vector-parasite interaction. Previous studies on laboratory reared Lu. longipalpis have provided a descriptive repertoire of gene expression in the whole insect, midgut, salivary gland and male reproductive organs. Nevertheless, the study of wild specimens would contribute a unique insight into the development of novel bioinsecticides. Given the recent VL outbreak in Argentina and the compelling need to develop appropriate control strategies, this study focused on wild male and female Lu. longipalpis from an Argentine endemic (Posadas, Misiones) and a Brazilian non-endemic (Lapinha Cave, Minas Gerais) VL location. In this study, total RNA was extracted from the sand flies, submitted to sequence independent amplification and high-throughput pyrosequencing. This is the first time an unbiased and comprehensive transcriptomic approach has been used to analyse an infectious disease vector in its natural environment. Transcripts identified in the sand flies showed characteristic profiles which correlated with the environment of origin and with taxa previously identified in these same specimens. Among these, various genes represented putative targets for vector control via RNA interference (RNAi). © 2013 McCarthy et al.


Catalano M.I.,National University of Buenos Aires Northeast Province | Paradell S.L.,National University of La Plata | Dietrich C.H.,University of Illinois at Urbana - Champaign
Zootaxa | Year: 2014

The Neotropical microleafhopper genera Paulomanus and Beamerana are redescribed based on study of type material and newly collected specimens. Paulomanus is recorded for the first time from Argentina and a new species, P. falciformis n. sp., is described. Detailed morphological description and illustration of the new species and a key to males of the known species of Paulomanus are provided. A key to genera of the New World Empoascini is also provided. Copyright © 2014 Magnolia Press.


Valdes-Hernandez A.,Federal University of Rio de Janeiro | Majtey A.P.,Federal University of Rio de Janeiro | Plastino A.R.,National University of Buenos Aires Northeast Province
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

Information that is stored in quantum-mechanical systems can be easily lost because of the interaction with the environment in a process known as decoherence. Possible physical implementations of many processes in quantum information theory involve systems of identical particles, whence comprehension of the dynamics of entanglement induced by decoherence processes in identical-particle open systems becomes relevant. Here we study the effects and concomitant entanglement evolution arising from the interaction between a system of two identical fermions and the environment for two paradigmatic quantum channels. Entanglement measures are introduced to quantify the entanglement between the different parties, and a study of the dynamics of entanglement for some particular examples is carried out. Our analysis, which includes also the evolution of an entanglement indicator based on an entropic criteria, offers insights into the dynamics of entanglement in open systems of identical particles, involving the emergence of multipartite genuine entanglement. The results improve our understanding of the phenomenon of decoherence and will provide strategies to control it. © 2015 American Physical Society.


Darriba G.N.,National University of La Plata | Munoz E.L.,National University of La Plata | Errico L.A.,National University of La Plata | Errico L.A.,National University of Buenos Aires Northeast Province | Renteria M.,National University of La Plata
Journal of Physical Chemistry C | Year: 2014

A detailed theoretical first-principles study of structural, electronic, and hyperfine properties at Sn and Ta sites of undoped and Ta-doped rutile SnO2 is presented, using the Full-Potential Augmented Plane Wave plus local orbitals (FP-APW+lo) method. In the Ta-doped systems, we performed calculations for two different charge states. The predicted electric-field- gradient (EFG) tensor, the key magnitude in this study, for both charge states of the impurity result to be almost equal and in good agreement with Time-Differential Perturbed γ-γ Angular Correlation (TDPAC) results in 181Ta-doped SnO2 thin films. This study enables at present to discuss the origin of the EFG and the role played by the structural anisotropic contractions introduced by the Ta atom and the impurity charge state on the hyperfine properties. To determine the correct charge state of the impurity, we performed energetic studies, predicting the metallic behavior of degenerate semiconductors, in agreement with resistivity experimental results obtained in samples with the same Ta dilution. © 2014 American Chemical Society.


Luque G.M.,CONICET | Perez-Millan M.I.,CONICET | Ornstein A.M.,CONICET | Cristina C.,National University of Buenos Aires Northeast Province | Becu-Villalobos D.,CONICET
Journal of Pharmacology and Experimental Therapeutics | Year: 2011

Prolactin-secreting adenomas are the most frequent type among pituitary tumors, and pharmacological therapy with dopamine agonists remains the mainstay of treatment. But some adenomas are resistant, and a decrease in the number or function of dopamine D2 receptors (D2Rs) has been described in these cases. D2R knockout [Drd2(-/-)] mice have chronic hyperprolactinemia and pituitary hyperplasia and provide an experimental model for dopamine agonist-resistant prolactinomas. We described previously that disruption of D2Rs increases vascular endothelial growth factor (VEGF) expression. We therefore designed two strategies of antiangiogenesis using prolactinomas generated in Drd2(-/-) female mice: direct intra-adenoma mVEGF R1 (Flt-1)/Fc chimera (VEGF-TRAP) injection for 3 weeks [into subcutaneously transplanted pituitaries from Drd2(-/-) mice] and systemic VEGF neutralization with the specific monoclonal antibody G6-31. Both strategies resulted in substantial decrease of prolactin content and lactotrope area, and a reduction in tumor size was observed in in situ prolactinomas. There were significant decreases in vascularity, evaluated by cluster of differentiation molecule 31 vessel staining, and proliferation (proliferating cell nuclear antigen staining) in response to both anti-VEGF treatments. These data demonstrate that the antiangiogenic approach was effective in inhibiting the growth of in situ dopamine-resistant prolactinomas as well as in the transplanted adenomas. No differences in VEGF protein expression were observed after either anti-VEGF treatment, and, although serum VEGF was increased in G6-31-treated mice, pituitary activation of the VEGF receptor 2 signaling pathway was reduced. Our results indicate that, even though the role of angiogenesis in pituitary adenomas is contentious, VEGF might contribute to adequate vascular supply and represent a supplementary therapeutic target in dopamine agonist-resistant prolactinomas. Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics.


Semeniuk M.B.,National University of La Plata | Merino M.L.,National University of Buenos Aires Northeast Province
Mammalia | Year: 2015

Pampas deer (Ozotoceros bezoarticus) is a medium-sized South American cervid associated with savannas and grasslands in Argentina, Brazil, Bolivia, Uruguay, and Paraguay. Currently, four isolated population nuclei occur in Argentina, with the largest one located in the semiarid grasslands of San Luis Province. The aim of this work was to describe the social organization of this local population and to determine and analyze the factors that influence it. The most frequent groups found were mixed groups (34.82%), followed by solitary males (18.64%), and solitary females (15.00%). Differences in group type occurrence were found in three periods: dry, early rainy, and late rainy seasons. Mixed groups were more frequent during the dry season. The sexual segregation-aggregation statistic showed statistically significant segregation only in January and November. In addition, we analyzed the social grouping patterns during an annual cycle; the mean group size was 2.49±0.46 and Jarman's typical group size was 3.84±1.08 (individuals/group). A mixed-model nested ANOVA showed marked differences in terms of group sizes between habitat types and seasons. The social organization of the Pampas deer in San Luis is similar to that of the other populations of this species, despite occupying a different environment type and exhibiting disparate feeding styles and density values. © 2015 by De Gruyter.


Plastino A.,National University of La Plata | Bellomo G.,National University of La Plata | Plastino A.R.,National University of Buenos Aires Northeast Province
International Journal of Quantum Information | Year: 2015

We argue that the dimensionality of the space of quantum systems' states should be considered as a legitimate resource for quantum information tasks. The assertion is supported by the fact that quantum states with discord-like capacities can be obtained from classically-correlated states in spaces of dimension large enough. We illustrate things with some simple examples that justify our claim. © 2015 World Scientific Publishing Company.


Torres M.J.,National University of Buenos Aires Northeast Province | Trejo S.A.,Autonomous University of Barcelona | Natalucci C.L.,National University of La Plata | Lopez L.M.I.,National University of La Plata
Planta | Year: 2013

The latex from Vasconcellea quercifolia ("oak leaved papaya"), a member of the Caricaceae family, contains at least seven cysteine endopeptidases with high proteolytic activity, which helps to protect these plants against injury. In this study, we isolated and characterized the most basic of these cysteine endopeptidases, named VQ-VII. This new purified enzyme was homogeneous by bidimensional electrophoresis and MALDI-TOF mass spectrometry, and exhibited a molecular mass of 23,984 Da and an isoelectric point >11. The enzymatic activity of VQ-VII was completely inhibited by E-64 and iodoacetic acid, confirming that it belongs to the catalytic group of cysteine endopeptidases. By investigating the cleavage of the oxidized insulin B-chain to establish the hydrolytic specificity of VQ-VII, we found 13 cleavage sites on the substrate, revealing that it is a broad-specificity peptidase. The pH profiles toward p-Glu-Phe-Leu-p-nitroanilide (PFLNA) and casein showed that the optimum pH is about 6.8 for both substrates, and that in casein, it is active over a wide pH range (activity higher than 80 % between pH 6 and 9.5). Kinetic enzymatic assays were performed with the thiol peptidase substrate PFLNA (Km= 0.454 ± 0.046 mM, kcat= 1.57 ± 0.07 s-1, kcat/Km = 3.46 × 103 ± 14 s-1 M-1). The N-terminal sequence (21 amino acids) of VQ-VII showed an identity >70 % with 11 plant cysteine peptidases and the presence of highly conserved residues and motifs shared with the "papain-like" family of peptidases. VQ-VII proved to be a new latex enzyme of broad specificity, which can degrade extensively proteins of different nature in a wide pH range. © 2013 Springer-Verlag Berlin Heidelberg.


Sterkel M.,National University of La Plata | Urlaub H.,Max Planck Institute for Biophysical Chemistry | Rivera-Pomar R.,National University of La Plata | Rivera-Pomar R.,National University of Buenos Aires Northeast Province | Ons S.,National University of La Plata
Journal of Proteome Research | Year: 2011

In hematophagous insects, blood intake triggers a prompt response mediated by neuropeptides, which regulates a variety of physiological processes. Here we report a quantitative proteomic analysis of the postfeeding response in the central nervous system of Rhodnius prolixus, a vector of Chagas disease. The concentration of neuropeptides NVP-like, ITG-like, kinin-precursor peptide, and neuropeptide-like precursor 1 (NPLP1) significantly changes in response to blood intake. We also performed a neuropeptidomic analysis of other feeding-related organs, namely salivary glands and gut. We identified NPLP1 in salivary glands and myosuppressin in midgut. This is the first report suggesting a role for NPLP1, involving the peptides processed from this precursor in the hormonal control of the production and/or release of saliva. Our results contribute to the understanding of the postprandial neuroendocrine response in hematophagous and provide important information for physiological and pharmacological studies aimed to the design of next-generation insecticides such as peptidomimetics. © 2011 American Chemical Society.


McCarthy C.B.,National University of La Plata | McCarthy C.B.,National University of Buenos Aires Northeast Province | Diambra L.A.,National University of La Plata | Pomar R.V.,National University of La Plata | Pomar R.V.,National University of Buenos Aires Northeast Province
PLoS Neglected Tropical Diseases | Year: 2011

Background: Leishmaniasis is one of the most diverse and complex of all vector-borne diseases worldwide. It is caused by parasites of the genus Leishmania, obligate intramacrophage protists characterised by diversity and complexity. Its most severe form is visceral leishmaniasis (VL), a systemic disease that is fatal if left untreated. In Latin America VL is caused by Leishmania infantum chagasi and transmitted by Lutzomyia longipalpis. This phlebotomine sandfly is only found in the New World, from Mexico to Argentina. In South America, migration and urbanisation have largely contributed to the increase of VL as a public health problem. Moreover, the first VL outbreak was recently reported in Argentina, which has already caused 7 deaths and 83 reported cases. Methodology/Principal Findings: An inventory of the microbiota associated with insect vectors, especially of wild specimens, would aid in the development of novel strategies for controlling insect vectors. Given the recent VL outbreak in Argentina and the compelling need to develop appropriate control strategies, this study focused on wild male and female Lu. longipalpis from an Argentine endemic (Posadas, Misiones) and a Brazilian non-endemic (Lapinha Cave, Minas Gerais) VL location. Previous studies on wild and laboratory reared female Lu. longipalpis have described gut bacteria using standard bacteriological methods. In this study, total RNA was extracted from the insects and submitted to high-throughput pyrosequencing. The analysis revealed the presence of sequences from bacteria, fungi, protist parasites, plants and metazoans. Conclusions/Significance: This is the first time an unbiased and comprehensive metagenomic approach has been used to survey taxa associated with an infectious disease vector. The identification of gregarines suggested they are a possible efficient control method under natural conditions. Ongoing studies are determining the significance of the associated taxa found in this study in a greater number of adult male and female Lu. longipalpis samples from endemic and non-endemic locations. A particular emphasis is being given to those species involved in the biological control of this vector and to the etiologic agents of animal and plant diseases. © 2011 McCarthy et al.

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