Mycobacterium bovis Δmce2 double deletion mutant protects cattle against challenge with virulent M. bovis Blanco, Federico Carlos; Bianco, María Verónica; Garbaccio, Sergio; Meikle, Virginia; Gravisaco, María José; Montenegro, Valeria Noely; Alfonseca, Edgar; Singh, Mahavir; Barandiaran, Soledad; Canal, Ana María; Vagnoni, Lucas; Buddle, Bryce Malcom; Bigi, Fabiana; Cataldi, Ángel Adrián A Mycobacterium bovis strain deleted in mce2A and mce2B genes (M. bovis Δmce2) was tested as an experimental vaccine in cattle challenged with a virulent M. bovis strain. Three-and-a-half-month old calves (n = 5 to 6 per group) were vaccinated and challenged with a virulent strain of M. bovis by the intratracheal route 9 weeks after vaccination. A non-vaccinated group and a group vaccinated with BCG were included as controls. Blood samples were collected to measure IFN-γ by an interferon-gamma release assay (IGRA), cytometry and cytokine responses of bovine purified protein derivative (PPD) restimulated peripheral blood mononuclear cells (PBMCs). The IGRA test showed IFN-γ values similar to pre-vaccination except for the animals vaccinated with M. bovis Δmce2, where a significant increase was observed at 30 days post-vaccination. The expression of IL-2R on CD4(+) cells in response to PPD from the animals vaccinated with Δmce2 increased at 15 days post-vaccination compared to cells from non-vaccinated group. Vaccination of cattle with M. bovis Δmce2 induced the highest (P < 0.05) expression of IFN-γ and IL-17 mRNA upon PPD stimulation of PBMCs compared to vaccination with BCG or that for the non-vaccinated group. There was a weak positive correlation between the production of these proinflammatory cytokines post-vaccination and reduced pathology scores post-challenge. The animals were euthanized and necropsied 100 days after challenge. The group vaccinated with M. bovis Δmce2 displayed a significantly lower histopathological score for lesions in lungs and pulmonary lymph nodes than for the other groups (P < 0.05). A marked positive reaction to tuberculin intradermal test was observed post-vaccination in animals vaccinated with M. bovis Δmce2 compared to those vaccinated with BCG or the non-vaccinated group. In contrast, after challenge, non-vaccinated animals had greater skin test responses than the vaccinated animals. In summary, M. bovis Δmce2 is a promising vaccine candidate to control M. bovis pathogenesis in cattle.

Viral etiology of acute respiratory infection in hospitalized and outpatient children from Buenos Aires, Argentina Marcone, Débora Natalia; Ellis, Alejandro; Videla, Cristina Mónica; Ekstrom, Jorge; Ricarte, Carmen; Carballal, Guadalupe; Vidaurreta, Santiago Manuel; Echavarría, Marcela Silvia OBJECTIVES: To determine and compare the viral frequency, seasonality and clinical-demographic features in 2 groups of children (hospitalized versus outpatients) with acute respiratory infections. MATERIAL AND METHODS: A cross-sectional, descriptive study was performed from 2008 to 2010 in 620 children <6 years of age with acute respiratory infection. Respiratory samples were studied for classical respiratory viruses by immunofluorescence and for human rhinoviruses (HRV) by real-time reverse transcription polymerase chain reaction. Clinical and demographic data were recorded. RESULTS: Viral detection by immunofluorescence was 48% in 434 inpatients and 37% in 186 outpatients. Viral diagnosis increased to 83% and 62%, respectively, when testing for HRV. HRV (41%) and respiratory syncytial virus (RSV) (27%) were most common viruses identified, followed by metapneumovirus (9%), influenza A and parainfluenza (3%), adenovirus and influenza B (2%). HRV frequency was significantly higher in hospitalized patients (47%) than in outpatients (27%) (P < 0.001). Coinfection was detected in 12% of hospitalized and 4% of outpatients (P < 0.031). HRV and adenovirus circulated throughout the entire year. RSV, influenza A and B predominated in winter, whereas metapneumovirus and parainfluenza predominated in spring. Of 362 patients with bronchiolitis, 84% had a virus identified; HRV (42%) and RSV (38%) were predominant. Of 77 patients with pneumonia, 84% had a virus detected with HRV (43%) and RSV (29%) predominating. CONCLUSIONS: HRV were significant pathogens associated with bronchiolitis and pneumonia, especially in hospitalized patients. Both, HRV and coinfections, were risk factors for hospitalization. These findings support the importance of including HRV detection in children with acute respiratory infection.

Phylogenetic analysis of bluetongue virus serotype 4 field isolates from Argentina. Legisa, Danilo Mario; González, Fernanda Gabriela; De Stefano, G.; Pereda, Ariel Julián; Dus Santos, María José Bluetongue (BT) is an insect-transmitted viral disease of ruminant species, which represents a major barrier to the international trade of animals and their products. Bluetongue virus (BTV) has a genome composed of ten linear segments of double-stranded RNA (dsRNA), which code for at least ten different viral proteins. In South America, serological evidence for the presence of BTV has been found in Peru, Argentina, Brazil, Ecuador and Chile. Brazil and Argentina are the only South American countries where BTV has been isolated. In Brazil, only one BTV isolate, serotype 12, has been reported, whereas in Argentina five BTV serotype 4 isolates have been obtained from cattle without clinical signs. Three of these five isolates were isolated during 1999-2001, whereas two of them were obtained as part of the present work. This study describes sequence comparisons and phylogenetic analyses of segments 2, 3, 6, 7 and 10 of the first Argentinean field isolates of BTV. The analysis of segments 2 and 6 resulted in a single cluster of Argentinean sequences into the serotype 4 clade. In addition, the Argentinean sequences grouped within the nucleotype A clade, along with reference strains. The analysis of segments 3, 7 and 10 showed that the Argentinean isolates grouped into the western topotype, indicating that the circulating virus had an African/European origin. Phylogenetic analysis revealed that the Argentinean sequences present a South American genetic identity, suggesting an independent lineage evolution.

The infant and pubertal human ovary: Balbiani's body-associated VASA expression, immunohistochemical detection of apoptosis-related BCL2 and BAX proteins, and DNA fragmentation Albamonte, María Itatí; Albamonte, Mirta S.; Stella, Inés; Zuccardi, Luis; Vitullo, Alfredo Daniel STUDY QUESTION: How do apoptosis-related BCL2 and BAX genes, known to regulate death or survival of germ cells in fetal and adult life, and germ-cell-specific VASA protein behave from birth to puberty in the human ovary? SUMMARY ANSWER: In resting primordial follicles in both infant and pubertal ovaries, BCL2 family members and germ-cell-specific VASA behave as in fetal life. After birth, once follicles leave the resting reserve to enter the growing follicular pool, detection of apoptosis-related genes moves from the germ cell to granulosa cells and VASA expression is lost. WHAT IS KNOWN ALREADY: In the human ovary, around 85% of the 7 × 106 potential oocytes produced at mid-gestation are lost before birth, an extra 10% before puberty, and loss continues throughout reproductive life until germinal exhaustion of the ovary. Oocyte loss is mainly driven through a balanced expression of BCL2 gene family members. Apoptosis-inducing BAX gene shows a sustained expression throughout fetal and adult life, whereas apoptosis-inhibiting BCL2 is detectable during the proliferative stage of primordial germ cells and oogonia in the fetal ovary and proliferation of granulosa cells in growing follicles in the adult ovary. The germ-cell marker VASA is detectable in the fetal ovary from early oogenesis and is conspicuously expressed in primordial follicles, where in late pregnancy it is associated with the Balbiani's vitelline space. VASA expression is not detectable in the adult ovary. STUDY DESIGN, SIZE, DURATION: This is a qualitative analysis involving infant/pubertal paraffin-embedded human ovaries screened for apoptosis-related proteins, DNA fragmentation and germ-cell identity. PARTICIPANTS/MATERIALS, SETTING, METHODS: Ovaries from 13 patients ranging in age from 4 to 16 years, undergoing gynaecological surgical procedures due to benign pathology, were studied. Tissues were fixed in 10% formalin, paraffin-embedded and processed for immunohistochemistry to screen the temporal and cellular localization of germ-cell-specific VASA protein and BCL2 and BAX apoptosis-related proteins. In addition, a terminal deoxynucleotidyl transferase-mediated deoxiuridinetriphosphate nick-end labelling (TUNEL) assay was performed to detect DNA fragmentation. General histology and tissue integrity were assessed by haematoxylin–eosin staining. MAIN RESULTS AND THE ROLE OF CHANCE: VASA showed a differential pattern of expression; in the resting primordial follicle reserve in infant and pubertal ovaries, it was associated with the Balbiani's body space in the germ cell. VASA remained detectable in primary follicles leaving the resting reserve, but once follicles entered the growing pool it became undetectable. This pattern of VASA expression is the same as in the fetal ovary. BAX was expressed both in the resting primordial reserve and in the pool of growing follicles, whereas BCL2 was detected only in granulosa cells in antral follicles in the growing pool. Apoptosis-related protein expression moved from the germ cell to the somatic stratum when primordial follicles left the resting reserve to enter the pool of growing follicles, irrespective of female age. Most TUNEL-positive cells were detected in the granulosa cells of antral follicles. No TUNEL-positive cells were found in resting primordial follicles. LIMITATIONS, REASONS FOR CAUTION: The study was limited by the qualitative nature of the immuno-histochemical analysis and the TUNEL assay. The results neither quantify the levels of germ-cell death nor exclude other concurrent cell death mechanisms that could act in the regulation of female germ-cell number. WIDER IMPLICATIONS OF THE FINDING: This study provides missing knowledge about apoptosis and germ-cell-specific VASA expression in the human ovary between birth and puberty and the participation of BCL2 and BAX genes in the balance between death and survival throughout female germ-line development. Intracellular localization of VASA in resting follicles emerges as a possible marker with prognostic value that needs further investigation, especially in infant patients entering ovarian cryo-preservation programmes. This knowledge will be valuable in optimizing the rescue and clinical use of germ cells to restore fertility in women. STUDY FUNDING/COMPETING INTEREST(S): No external funding was obtained for this study. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: Not applicable.

Mechanistic studies on the photodynamic effect induced by a dicationic fullerene C60 derivative on Escherichia coli and Candida albicans cells Milanesio, María Elisa; Spesia, Mariana Belen; Cormick, Maria Paula; Durantini, Edgardo Néstor The photodynamic mechanism of action induced by N,N-dimethyl-2-(4′-N,N,N-trimethylaminophenyl)fulleropyrrolidinium iodide (DTC602+) was investigated on Candida albicans and Escherichia coli cells. First, photogeneration of superoxide anion radical by DTC602+ in the presence of NADH was detected using nitro blue tetrazolium method in reverse micelles. In C. albicans suspensions, 10 μM DTC602+ was an effective photosensitizer, producing a ∼5 log decrease of cell survival when the cultures were irradiated for 30 min with visible light. Also, C. albicans cells growth was not detected in the presence of 10 μM DTC602+ and irradiation. Photodynamic mechanism investigations were compared in both C. albicans and E. coli cells. Studies under anoxic conditions indicated that oxygen was required for the photodynamic inactivation of these microorganisms. The photocytotoxicity induced by DTC602+ was similar in D2O than in water cell suspensions. Furthermore, photoinactivation of microbial cells was negligible in the presence of azide ion, while the addition of mannitol produced a photoprotective effect on the cellular survival. These results indicate that DTC602+ has potential as agent to the photodynamic inactivation of microbial cells. Also, the photocytotoxicity activity induced by this cationic fullerene derivative can involve the intermediacy of both superoxide anion radical and singlet molecular oxygen.

Sequence variability in p6 gag protein and gag/pol coevolution in Human Immunodeficiency Type 1 Subtype F genomes Rossi, Andrés Hugo; Rocco, Carlos Alberto; Mangano, Andrea María Mercedes; Sen, Luisa; Aulicino, Paula Polymorphisms occurring at the p6gag protein of HIV-1 have been previously found to have an impact on viral fitness and antiretroviral (ARV) resistance, mainly on subtype B genomes. We compared p6gag variability in a large group of 165 subtype F gag-pol sequences, with 36 subtype B sequences from the same study source, and identified sites of gag-pol coevolution under ARV selection pressure. Subtype-specific differences in the frequency of point mutations, insertions, and deletions previously associated with ARV resistance were found. Also, in our dataset of subtype F genomes a strong association between mutation P5L in the p1/p6 cleavage region of gag and the nelfinavir (NFV) resistance mutation N88DPR was found with no impact on the preference for any of the NFV resistance pathways.

Estradiol, progesterone and prolactin modulate mammary gland morphogenesis in adult female plains vizcacha (Lagostomus maximus) Halperin, Julia; Dorfman, Verónica Berta; Fraunhoffer Navarro, Nicolas Alejandro; Vitullo, Alfredo Daniel We studied for the first time the mammary gland morphogenesis and its hormonal modulation by immunolocalizing estradiol, progesterone and prolactin receptors (ER, PR and PRLR) in adult females of Lagostomus maximus, a caviomorph rodent which shows a pseudo-ovulatory process at mid-gestation. Mammary ductal system of non-pregnant females lacks expression of both ERα and ERβ. Yet throughout pregnancy, ERα and ERβ levels increase as well as the expression of PR. These increments are concomitant with ductal branching and alveolar differentiation. Even though mammary gland morphology is quite similar to that described for other rodents, alveolar proliferation and differentiation are accelerated towards the second half of pregnancy, once pseudo-ovulation had occurred. Moreover, this exponential growth correlates with an increment of both progesterone and estradiol serum-induced pseudo-ovulation. As expected, PR and PRLR are strongly expressed in the alveolar epithelium during pregnancy and lactation. Strikingly, PRLR is also present in ductal epithelia of cycling glands suggesting that prolactin function may not be restricted to its trophic effect on mammary glands of pregnant and lactating females, but it also regulates other physiological processes in mammary glands of non-pregnant animals. In conclusion, this report suggests that pseudo-ovulation at mid-gestation may be associated to L. maximus mammary gland growth and differentiation. The rise in P and E2-induced pseudo-ovulation as well as the increased expression of their receptors, all events that correlate with the development of a more elaborated and differentiated ductal network, pinpoint a possible relation between this peculiar physiological event and mammary gland morphogenesis.

Pyrrhonism, inquiry, and rationality Machuca, Diego Emanuel This paper offers a detailed examination of the Skeptic´s philosophical investigation and his attitude towards the requirements of rationality. In so doing, it engages with the interpretation advanced by Casey Perin in his recent book: The Demands of Reason: An Essay on Pyrrhonian Scepticism (OUP, 2010).

Emerging drugs for autonomic dysfunction in Parkinson's disease Pérez Lloret, Santiago; Rey, María Verónica; Pavy Le Traon, Anne; Rascol, Olivier Introduction: Autonomic dysfunction, including orthostatic hypotension (OH), sialorrhea, sexual dysfunction, urinary dysfunction and constipation is a common feature of Parkinson’s disease (PD). Even though its treatment has been recognized as a major unmet need in PD, there is a paucity of clinical trials to assess their treatment. Areas covered: Evidence about the efficacy and safety of available treatments for autonomic dysfunction is summarized. Potential targets for upcoming therapies are then discussed in light of what is currently known about the physiopathology of each disorder in PD. Proof-of-concept trials and circumstantial evidence about treatments for autonomic dysfunction as well as upcoming clinical trials are discussed. Finally, critical aspects of clinical trials design are considered. Expert opinion: Botulinum toxin (BTX) or glycopyrrolate might be used for sialorrhea whereas macrogol could be useful in constipation. There is preliminary evidence suggesting that fludrocortisone, domperidone, droxidopa or fipamezole may be effective for the treatment of OH. Tropicamide, clonidine or radiotherapy are under development for sialorrhea. Sildenafil may be effective for the treatment of erectile dysfunction; BTX or behavioral therapy for urinary incontinence and lubiprostone and probiotics for constipation. Sound clinical trials are needed in order to allow firm evidence-based recommendations about these treatments.

Composición fisicoquímica y calidad microbiológica de leche de cabra producida en la provincia de Santiago del Estero (Argentina); Physicochemical composition and microbiological quality of goat milk produced in Santiago del Estero Province (Argentine) Frau, Silvia Florencia; Font, Graciela Maria; Paz, Raul Gustavo; Pece Azar, Nora Beatriz del Carmen La mayor cuenca lechera caprina de Argentina está ubicada en la provincia de Santiago del Estero, pero existe escaso conocimiento de la calidad de leche producida allí. El presente trabajo constó de dos fases y tuvo como objetivo analizar la composición fisicoquímica y calidad microbiológica de la leche de cabra de esta cuenca lechera. En la primera fase se analizó la leche procedente de 30 pequeños tambos sin raza animal definida y se obtuvieron los siguientes valores medios: grasa, 5.37%; proteína, 3.39%; lactosa, 4.32%; sólidos no grasos (SNG), 8.30%; sólidos totales (ST), 13.66%; acidez, 17.61ºD; pH, 6.76; densidad, 1.031g/mL; aerobios mesófilos totales, 4.96 log ufc/mL y proporción de muestras positivas de coliformes fecales, 72%. En la segunda fase, se seleccionaron tres tambos con razas lecheras definidas y volúmenes de producción superiores a la media de la zona. La leche de estos tambos no difirió mucho de la composición fisicoquímica ya citada, pero se destacaron dos de los mismos (T2 y T3) por sus respectivos contenidos de grasa (5.59 y 5.52%) y ST (14.18 y 13.84%), resultado de su uso de la raza Anglo Nubian y alimentación mediante pastoreo de pasturas naturales y suplementación con cereales. El T1, que usa la raza Saanen presentó la mayor producción media de leche, de 1.44 kg/d y la acidez más baja, de 16.49ºD, resultado de mejores condiciones de manejo del tambo y enfriamiento de la leche postordeño. Se concluye que aun haciendo falta mejorar el manejo higiénicosanitario que recibe la leche cruda, la leche de esta cuenca se presta muy bien para la elaboración de queso.; The largest caprine milk shed of Argentina is located in Santiago del Estero province, but little information is available about the quality of the milk produced there. The present study consisted of two phases and had the objective of analyzing the physical-chemical composition and microbiological quality of the goat’s milk of this milk shed. In the first phase, milk from 30 small producer operations without defined animal breeds were analyzed with the following mean results: fat, 5.37%; protein, 3.39%; lactose, 4.32%; solids/not/fat (SNF), 8.30%; total solids (TS) 13.66%; acid degree value, 17.61ºD; pH, 6.76; density, 1.031 g/mL; total aerobic mesophiles, 4.96 log cfu/mL and proportion of samples positive for fecal coliforms, 72%. The second phase of the study involved three goat farms with different breeds and production levels exceeding the average of the zone. The milk from these farms did not differ much from the physical-chemical composition cited above, but two of them (T2 and T3) had outstanding contents of fat (5.59 and 5.52%) and TS (14.13 and 13.84%), resulting from their use of the Anglo Nubian breed and feeding based on grazing of natural pastures and supplementation with cereals. The farm T1, that employs the Saanen breed, had the highest mean milk production (1.44 kg/day) and the lowest acid degree value (16.49ºD), resulting from better management of the operation and more efficient cooling of the milk after milking. It is concluded that, eventhough better hygienic/sanitary management of the crude milk is needed, milk from this milk shed is well suited for cheese making.

Los brokers del desarrollo en comunidades indígenas del noroeste argentino: ¿promotores rurales, técnicos estatales y/o miembros de ONG? Castelnuovo Biraben, Natalia Sabrina El trabajo parte de una investigación etnográfica acerca de las formas que asume el ‘desarrollo’ en comunidades indígenas rurales del noroeste argentino para analizar las prácticas de actores sociales vinculados al desarrollo local. Este estudio explora cómo se desenvuelven los brokers del desarrollo a través de la actuación de una ONG local durante la implementación de un programa estatal en el marco de un proceso de lucha y movilización indígena frente a la construcción de un gasoducto. Al presentar este acontecimiento se busca poner de relieve las múltiples posiciones que los brokers adoptan de acuerdo al contexto e interlocutores, ya sea asumiendo un rol como técnicos estatales o integrantes de una ONG. Este hecho echa luz acerca de la labilidad entre las prácticas que definen el ser agente de desarrollo estatal del ser miembro de una ONG, poniendo en discusión la idea de que se tratarían, como algunos autores han planteado, de bloques antagónicos cuando en realidad lo que surge del análisis es que entre las prácticas de los agentes estatales y de la sociedad civil existen fronteras porosas.

Safety auxiliary feedback element for the artificial pancreas in type 1 diabetes Revert, A.; Garelli, Fabricio; Picó, J.; de Battista, Hernán; Rossetti, P.; Vehi, J.; Bondia, J. The artificial pancreas aims at the automatic delivery of insulin for glycemic control in patients with type 1 diabetes, i.e., closed-loop glucose control. One of the challenges of the arti- ficial pancreas is to avoid controller overreaction leading to hypoglycemia, especially in the late postprandial period. In this study, an original proposal based on sliding mode reference conditioning ideas is presented as a way to reduce hypoglycemia events induced by a closed-loop glucose controller. The method is inspired in the intuitive advantages of two-step constrained control algorithms. It acts on the glucose reference sent to the main controller shaping it so as to avoid violating given constraints on the insulin-on-board. Some distinctive features of the proposed strategy are that 1) it provides a safety layer which can be adjusted according to medical criteria; 2) it can be added to closed-loop controllers of any nature; 3) it is robust against sensor failures and overestimated prandial insulin doses; and 4) it can handle nonlinear models. The method is evaluated in silico with the ten adult patients available in the FDA-accepted UVA simulator.

N-terminal palmitoylation is required for Toxoplasma gondii HSP20 inner membrane complex localization de Napoli, Maximiliano Gabriel; de Miguel, Natalia; Lebrun, M.; Moreno, S. N. J.; Ángel, Sergio Oscar; Corvi, Maria Martha Toxoplasma gondii is an obligate intracellular parasite and the causative agent of toxoplasmosis. Protein palmitoylation is known to play roles in signal transduction and in enhancing the hydrophobicity of proteins thus contributing to their membrane association. Global inhibition of protein palmitoylation has been shown to affect T. gondii physiology and invasion of the host cell. However, the proteins affected by this modification have been understudied. This paper shows that the small heat shock protein 20 from T. gondii (TgHSP20) is synthesized as a mature protein in the cytosol and is palmitoylated in three cysteine residues. However, its localization at the inner membrane complex (IMC) is dependent only on N-terminal palmitoylation. Absence or incomplete N-terminal palmitoylation causes TgHSP20 to partially accumulate in a membranous structure. Interestingly, TgHSP20 palmitoylation is not responsible for its interaction with the daughter cells IMCs. Together, our data describe the importance of palmitoylation in protein targeting to the IMC in T. gondii.

Oxidovanadium(IV) and dioxidovanadium(V) complexes of tridentate salicylaldehyde semicarbazones: Searching for prospective antitrypanosomal agents Fernández, Mariana; Becco, Lorena; Correia, Isabel; Benítez, Julio; Piro, Oscar Enrique; Echeverría, Gustavo Alberto; Medeiros, Andrea; Comini, Marcelo; Lavaggi, María Laura; González, Mercedes; Cerecetto, Hugo; Moreno, Virtudes; Costa Pessoa, Joao; Garat, Beatriz; Gambino, Dinorah As a contribution to the identification of the relevant species for biological activity and the understanding of structure–activity relationships of [VIVO(L-2H)(NN)] antitrypanosomal complexes (NN is a bidentate polypyridyl DNA intercalator; L is a tridentate salicylaldehyde semicarbazone derivative), new [VVO2(L-2H)] complexes and [VIVO(L-2H)(NN)] complexes including bipy or dppz (dipyrido[3,2-a: 2′,3′-c]phenazine) co-ligands are prepared and characterized in the solid state and in solution. Their activity is evaluated on Trypanosoma cruzi. The lipophilicity, as structural descriptor related to bioactivity, of the whole [VIVO(L-2H)(NN)] series is determined. Furthermore, the antiproliferative effect of those new compounds showing activity against T. cruzi is evaluated on the genetically related parasite T. brucei with the aim to develop broad spectrum agents. The new [VIVO(L-2H)(dppz)] complexes are about ten to fifteen times more toxic to T. cruzi than the bipy analogues and show quite good in vitro activity on T. brucei brucei. They are shown to interact with DNA, suggesting that this biomolecule may be the parasite target. The stability of the VIVO-complexes in solution is accessed by several techniques. Globally the data suggest that the relevant species for biological activity are the [VIVO(L-2H)(NN)] compounds, their order of activity being dependent on the NN nature, but not much on the substitution on the salicylaldehyde semicarbazone moiety. A parabolic relationship between biological response and lipophilicity (determined as RM = log [(1 / Rf) − 1] by a TLC method) is obtained. From this correlation an optimum RM value, close to 1.44, was found, which may be used as design guide for future development of antitrypanosomal compounds.

Interaction between continental and estuarine waters in the wetlands of the northern coastal plain of Samborombón Bay, Argentina Carol, Eleonora Silvina; Mas Pla, Josep; Kruse, Eduardo Emilio On the Samborombón Bay coastline, located in the Río de la Plata estuary in Buenos Aires province (Argentina), a complex hydrological system has developed at the interface between continental and estuarine water, where significant wetlands develop. The main hydrogeological units, namely the shell ridges, the tidal plain and the marsh areas, have been identified using geomorphological criteria. Water table, hydrochemical and isotopic data have been used to determine their hydrological features, as well as those of the streams and canals. Evaporation processes, in particular, have been considered when depicting chemical and isotopic changes in surface waters in streams and marsh areas. The shell ridges represent a hydrogeological unit in which rainwater is stored, constituting a lens-shaped freshwater aquifer. In this unit, just as in the tidal plain, carbonate dissolution and ion exchange are the main processes regulating water chemistry. On the other hand, in the marsh and surface waters, processes such as mixing with estuarine water and evaporation predominate. These processes control water fluxes and the salinity of the wetland areas and, consequently, their ability to preserve the existing biodiversity. This study shows the importance of knowledge of hydrochemical processes in any proposal concerning the management and preservation of this type of wetland.

Where is historical biogeography going? The evolution of the discipline in the first decade of the 21st century Posadas, Paula Elena; Grossi, Mariana Andrea; Ortiz Jaureguizar, Edgardo It has been argued that historical biogeography, the study of how processes that occur over long periods of time influence the distribution of life forms, is in the midst of a scientific revolution. The aim of this paper is to analyze the evolution of historical biogeography during the first decade of the 21st century and to identify major trends for the near future. We constructed a database containing all articles which dealt with historical biogeography published in the Journal of Biogeography during 1998–2010. The database included 610 contributions. Our results indicated that historical biogeography is going through a growth period. The papers analyzed were written by 2018 authors, with a mean of 3.3 authors per paper. Authors from 62 countries were involved, and most of them worked in Europe or North America. The Palearctic was the most analyzed region. Most contributions dealt with terrestrial habitats and were devoted to animal (especially Chordata) and plant taxa. Phylogeography was the most used approach (35%), followed by biota similarity and PAE (13%) and molecular biogeography (12%), with cladistic biogeography and event-based methods at 6% each. Some of the future challenges that historical biogeography faces are summarized: (1) to increase the study of taxa which are underrepresented according to the segment of biodiversity they represent; (2) to balance the amount of work devoted to different biogeographical regions; (3) to increase biogeographical knowledge of aquatic habitats; (4) to maintain the diversity of approaches, preventing the reduction of time, spatial, and taxonomic scales addressed by the discipline; and (5) to continue integrating historical biogeography along with other sources of information from other disciplines (e.g. ecology, paleontology, geology, isotope chemistry, remote sensing) into a richer context for explaining past, present, and future patterns of biodiversity on Earth.

Evolución paleoambiental de cordones litorales holocenos durante una caída del nivel del mar en la Bahía Samborombón, Buenos Aires, Argentina; Palaeoenvironmental evolution of Holocene littoral ridges during a sea level fall at Bahía Samborombón, Buenos Aires, Argentina Richiano, Sebastián Miguel; Varela, Augusto Nicolás; D'Elia, Leandro; Bilmes, Andrés; Aguirre, Marina Laura Las grandes fluctuaciones climáticas cíclicas ocurridas durante el Cuaternario tuvieron un efecto muy marcado en las regiones costeras, afectando principalmente el ambiente geomorfológico y la sedimentación de los depósitos allí acumulados. El mejor entendimiento de los sistemas depositacionales litorales generados en el pasado más reciente representa una herramienta fundamental para reconstruir y comprender otros depósitos similares del registro geológico, así como para desarrollar predicciones sobre posibles escenarios de cambios climáticos futuros. En el área costera de la Bahía Samborombón, noreste de la provincia de Buenos Aires, se encuentran preservados excelentes depósitos litorales acumulados con posterioridad al Último Máximo Glacial, durante la transgresión holocena. Sobre la base del análisis de facies se reconocieron cinco unidades de acumulación: cordón arenoso, cordón bioclástico, depósitos de sobrelavado, planicie de mareas y albufera. El análisis arquitectural y la jerarquización de superficies de discontinuidad permitieron elaborar un modelo de acumulación dinámico de los cordones de playa y ambientes asociados en diferentes etapas durante el Holoceno (ca. 8000 a A.P.- presente). El análisis estratigráfico secuencial permitió establecer la interacción de dos controles alocíclicos predominantes: eustático (regresión forzada) y climático (Óptimo Climático del Holoceno medio). La interacción de ambos factores extrínsecos no sólo condicionó la acumulación y amalgamación de geoformas cordoniformes, sino también, la relación entre aporte terrígeno y productividad carbonática de los depósitos.; In the Argentinean littoral zone several transgressive - regressive events took place during the Quaternary. Excellent examples of these events are recorded in the Bahía Samborombón coastal area in northeastern Buenos Aires province (Fig. 1). Following the stratigraphic scheme of Fidalgo et al. (1973) modified by Fucks et al. (2010), deposits of the Canal de las Escobas Formation (Holocene) were analyzed (Figs. 2, 3). The Canal de las Escobas Formation was discriminated into 4 members (Fucks et al., 2010), the Destacamento Río Salado Member (tidal flat, 5.8-7 ka B.P.), the Cerro de la Gloria Member (beach ridge, ca. 3-8 ka B.P.), the Canal 18 Member (coastal plain, 6-7 ka B.P.) and the Canal 15 Member (coastal plain, 3 ka B.P. to present). Fourteen detailed sedimentary sections were logged in the study area (Fig. 4), taking into account lithology, primary sedimentary structures, geometries of the sedimentary bodies with their orientation and the hierarchy of the bounding surfaces, as well as the palaeontological (predominantly molluscan) content. Thirteen sedimentary facies were defined (Figs. 5, 6) which were grouped into three major divisions: siliciclastic sandstones, fine-grained siliciclastic and carbonatic bioclastic rocks. The excellent preservation of the Canal de las Escobas Formation in the study area allowed the recognition of five sedimentary units based on the spatial facies arrangement and the hierarchy of internal surfaces. These units are: sand and bioclastic ridge, washover, lagoon and coastal plain units (Figs. 7, 8, 9, 10, 11). In order to determine the palaeoenvironmental evolution, based on the stacking patterns of the sedimentary units together with the hierarchy of the sedimentary discontinuity surfaces, six stages were devised after the maximum Holocene transgression (Fig. 12). Stages 1 and 2 correspond to the development of a sand ridge as a response to the erosion and reworking of a previous spit system (Fig. 3; Facies Pinamar). Subsequently, during stages 3 to 5, a bioclastic ridge was amalgamated with the sand ridge (Fig. 12). Simultaneously to these five stages, in a landward position, lagoon and washover deposits were developed (Fig. 12). Finally, during stage 6 the continuous sea level fall generated the actual coastal plain deposits (Fig. 12). The sudden change in the ridge deposits composition, from sandy sediments to almost exclusively bioclastic (carbonate) between stages 2 and 3 can be interpreted as the combined result of an increase in carbonate productivity along with a decrease of siliciclastic supply together the coast. This stage would have been developed approximately 5-6 ka B.P. (Marine Isotope Stage, MIS, 1), in coincidence with the Holocene Climatic Optimum or Mid-Holocene Thermal Maximum (sensu Briner et al., 2006) during which the very special climatic conditions may have led to the proliferation of large communities of benthic organisms, particularly bivalve mollusks, which are not so abundant today. The high occurrence of Mactra isabelleana in the beach ridges of Bahía Samborombón, including all dimensions and ontogenetic stages and excellent preservation of the shells, indicates that this bivalve represents an autochthonous element of the coastal native communities, suggesting high adaptive radiation of this species in the area and time span considered, when atmospheric-oceanic circulation patterns / changes in the prevalent shallow oceanic currents are documented by different sources of evidence (palaeobiodiversity, palaeobiogeography, stable isotopes) and the warm Brazilian current (moving southwards) prevailed over the cold Malvinas current (flowing northwards) (Fig. 3). This change in the intensities of the ocean currents would have originated a dual effect: firstly, a greater contribution of warm-temperature waters to the bay and secondly, the change in the terrigenous input. The contribution of sand, due to erosion and reworking of the previous spit facies, would have drastically decreased, whereas the contribution of terrigenous may have been restricted from the north coming from the Río de la Plata (Fig. 3). Nevertheless, no changes in composition and/or texture were observed in siliciclastic material between the sand and bioclastic ridges units. This would be related to the sort of material transported by the Río de la Plata, which is mostly pelitic and potentially washed by tidal activity as it is well documented for similar Quaternary deposits from other areas (Meldahl, 1995). Considering the whole dataset gathered, we propose an alternative sequence stratigraphic scheme for the Holocene ridge development from Bahía Samborombón (Fig. 13). This ridge is now considered originated as a consequence of a forced regression (ie. part of a falling stage system tract) instead of the previously interpretation during the late stage of sea level rise (ie. part of a highstand system tract). Both eustatic and climatic controls can be recognized, although with different orders of magnitude, which controlled the genesis of the studied deposits. In turn, this study provides an example of the strong changes occurred in coastal environments as a result of climate change, particularly in the context of global warming episodes which characterized interglacial periods of the Quaternary in South America (e.g. MIS 1, 5, 11).

Pollen morphology and its taxonomic significance in the tribe Gochnatieae (Compositae, Gochnatioideae) Tellería, María Cristina; Sancho, Gisela; Funk, Vicky A.; Ventosa, Iralys; Roque, Nadia In the context of recent molecular phylogenies of the basal grades of Compositae, we investigated the utility of pollen morphology within the tribe Gochnatieae. The pollen of 64 species of Anastraphia, Cnicothamnus, Cyclolepis, Gochnatia, Pentaphorus, and Richterago was studied using light microscopy and scanning electron microscopy. In addition, three extra-Gochnatieae genera (Ianthopappus, Leucomeris, and Nouelia) were examined as they were traditionally morphologically related to members of the tribe Gochnatieae. Three of the species of Gochnatieae were examined using transmission electron microscopy. Two pollen types, and two new subtypes, have been recognized on the basis of the pollen shape, size, and exine sculpture. The pollen features of Gochnatia sect. Moquiniastrum and G. cordata are similar and distinctive within the genus and support the recently re-circumscribed section Hedraiophyllum. Within the species with echinate pollen surface, the distinctive spine length of Anastraphia supports its recent resurrection as a genus. The identity of Pentaphorus could not be supported by pollen features as was for other morphological characteristics. The pollen features shared across Cyclolepis, Ianthopappus, Leucomeris, Nouelia and Gochnatia sect. Moquiniastrum, as well as those shared by Richterago and Anastraphia could be a result of parallel evolution

Short-Term Scheduling of Combined Cycle Units Using Mixed Integer Linear Programming Solution Alemany, Juan Manuel; Moitre, Diego Carlos Alberto; Pinto, Herminio; Magnago, Fernando Combined cycle plants (CCs) are broadly used all over the world. The inclusion of CCs into the optimal resource scheduling causes difficulties because they can be operated in different operating configuration modes based on the number of combustion and steam turbines. In this paper a model CCs based on a mixed integer linear programming approach to be included into an optimal short term resource optimization problem is presented. The proposed method allows modeling of CCs in different modes of operation taking into account the non convex operating costs for the different combined cycle mode of operation.

Production of reactive oxygen species in peanut nodules Carlier, Evelin; Castro, Stella Maris; Fabra, Adriana Isidora In this study, it was investigated the reactive oxygen species (ROS) production in peanut nodules at three peanut growth stages (R): R1 (flowering), R4 (full pod) and R6 (full seed). Analysis of ROS production showed that superoxide anion and hydrogen peroxide contents decreased while lipid peroxidation and protein oxidation remained unchanged throughout nodule development. Furthermore, it was found that the inside of formed nodules was 100% red at (R1), 54% at (R4) and 39% at (R6), respectively. The total soluble protein content decreased while leghemoglobin content remained unaltered at different growth stages. Thus, our findings suggest that ROS production is not involved in the peanut nodule senescence indicating that this process would not be accompanied by an oxidative burst. It is possible to suggest that the antioxidant system would play an important role in the protection of peanut nodules against ROS production.