Boundaries of Morphological and Molecular Variation and the Distribution of a Miniaturized Froglet, Brachycephalus nodoterga (Anura: Brachycephalidae) Clemente Carvalho, Rute B. G.; Perez, Sergio Ivan; Tonhatti, Carlos H.; Condez, Thais H.; Sawaya, Ricardo J.; Haddad, Celio F. B.; Dos Reis, Sergio F. Most miniaturized froglets of the genus Brachycephalus occur in isolation in slopes of mountain ranges at elevations varying from 600 to 1,800 m in the Atlantic Forest of eastern Brazil. For organisms such as Bracycephalus with spatially discontinuous distributions, a fundamental task is to determine whether observed patterns of variation are consistent with geographic differentiation among allopatric populations within a single species or are suggestive of a potential species boundary. We address this problem by focusing on continental and island population samples potentially assignable to Brachycephalus nodoterga (Anura: Brachycephalidae) from the perspective of variation in qualitative and quantitative morphological traits and DNA sequences. Population samples from continental and island populations share color characteristics, qualitative traits, and multivariate patterns of variation and covariation in cranial metric traits. Comparative analysis of DNA sequences showed the magnitude of molecular distances between B. nodoterga and Brachycephalus ephippium to be 1 order of magnitude larger than molecular distances within B. nodoterga and B. ephippium. We interpret the combined morphological and molecular evidence to indicate that continental and island population samples examined here are conspecific. Therefore, by defining species boundaries for B. nodoterga, we also established minimal estimates of its distribution.

Marine bacterial community structure resilience to changes in protist predation under phytoplankton bloom conditions Baltar, Federico; Palovaara, Joakim; Unrein, Fernando; Catala, Philippe; Horňák, Karel; Šimek, Karel; Vaqué, Dolors; Massana, Ramon; Gasol, Josep M.; Pinhassi, Jarone To test whether protist grazing selectively affects the composition of aquatic bacterial communities, we combined high-throughput sequencing to determine bacterial community composition with analyses of grazing rates, protist and bacterial abundances and bacterial cell sizes and physiological states in a mesocosm experiment in which nutrients were added to stimulate a phytoplankton bloom. A large variability was observed in the abundances of bacteria (from 0.7 to 2.4 × 10 6 cells per ml), heterotrophic nanoflagellates (from 0.063 to 2.7 × 10 4 cells per ml) and ciliates (from 100 to 3000 cells per l) during the experiment (∼3-, 45- and 30-fold, respectively), as well as in bulk grazing rates (from 1 to 13 × 10 6 bacteria per ml per day) and bacterial production (from 3 to 379 μg per C l per day) (1 and 2 orders of magnitude, respectively). However, these strong changes in predation pressure did not induce comparable responses in bacterial community composition, indicating that bacterial community structure was resilient to changes in protist predation pressure. Overall, our results indicate that peaks in protist predation (at least those associated with phytoplankton blooms) do not necessarily trigger substantial changes in the composition of coastal marine bacterioplankton communities.

dsRNA-protein interactions studied by molecular dynamics techniques. Unravelling dsRNA recognition by DCL1 Drusin, Salvador Iván; Suarez, Irina Paula; Gauto, Diego Fernando; Rasia, Rodolfo Maximiliano; Moreno, Diego Martin Double stranded RNA (dsRNA) participates in several biological processes, where RNA molecules acquire secondary structure inside the cell through base complementarity. The double stranded RNA binding domain (dsRBD) is one of the main protein folds that is able to recognize and bind to dsRNA regions. The N-terminal dsRBD of DCL1 in Arabidopsis thaliana (DCL1-1), in contrast to other studied dsRBDs, lacks a stable structure, behaving as an intrinsically disordered protein. DCL1-1 does however recognize dsRNA by acquiring a canonical fold in the presence of its substrate. Here we present a detailed modeling and molecular dynamics study of dsRNA recognition by DCL1-1. We found that DCL1-1 forms stable complexes with different RNAs and we characterized the residues involved in binding. Although the domain shows a binding loop substantially shorter than other homologs, it can still interact with the dsRNA and results in bending of the dsRNA A-type helix. Furthermore, we found that R8, a non-conserved residue located in the first dsRNA binding region, recognizes preferentially mismatched base pairs. We discuss our findings in the context of the function of DCL1-1 within the microRNA processing complex.

Cambios morfológicos producidos por el Parasitismo de Strelkovimermis Spiculatus Poinar & Camino, 1986 (Nematoda, Mermithidae): En larvas del mosquito Culex Pipiens Linneaus, 1758 (Diptera, Culicidae); Morphological changes caused by parasitism of Strelkovimermis spiculatus (Nematoda, Mermithidae) in Culex Pipiens mosquito larvae (Diptera, Culicidae) Reboredo, Guillermo Raul; González, Sandra Elizabeth; Rusconi, José Matías; Camino, Nora Beatriz El presente estudio evalúa el efecto del parasitismo de Strelkovimermis spiculatus Poinar & Camino, 1986 (Nematoda, Mermithidae), sobre larvas del mosquito Culex pipiens Linnaeus, 1758 (Diptera, Culicidae) a nivel histopatológico. Debido a la presencia del nemátodo que se evidencia por sus estructuras tales como los homorocitos, esticocitos, cuerdas longitudinales y trofosoma, se observó una alteración principalmente a nivel del epitelio intestinal, el cuerpo graso y la musculatura de la larva.; This study reports the effect of parasitism of the mermithid Strelkovimermis spiculatus Poinar & Camino, 1986 (Nematoda, Mermithidae)parasitizing larvae of the mosquito Culex pipiens Linneaus, 1758 (Diptera, Culicidae) at histopathological level. Due to the presence of nematode,evidenced by their structures such as longitudinal chords and trophosome, we observed changes mainly at the intestinal epithelium, fat body andmuscle of the larva.

Sentidos sobre la política en las memorias sobre la toma de la Escuela de Educación Técnica Nº 1 de Bahía Blanca en 1973 Seitz, Ana Inés El artículo aborda las memorias de exalumnos de la Escuela de Educación Técnica N° 1 de Bahía Blanca sobre la toma del colegio en junio de 1973, a pocos días de la asunción de Héctor Cámpora como presidente. En estos relatos es posible reconocer dos grupos distintos. Por un lado, el de quienes enfatizan el carácter apolítico de la medida, fundando la acción en reclamos exclusivamente gremiales. Por el otro, el de aquellos que, por el contrario, señalan que la ocupación de la escuela fue generada por la injerencia de sectores del peronismo de izquierda local. A través del análisis de las memorias de estos exestudiantes sobre el proceso de ocupación del colegio en 1973, este trabajo se propone indagar en los sentidos que la política y la militancia política adquieren para ellos en el presente.

FARGO3D: A new GPU-oriented MHD code Benítez Llambay, Pablo; Masset, Frédéric S. We present the FARGO3D code, recently publicly released. It is a magnetohydrodynamics code developed with special emphasis on the physics of protoplanetary disks and planet-disk interactions, and parallelized with MPI. The hydrodynamics algorithms are based on finite-difference upwind, dimensionally split methods. The magnetohydrodynamics algorithms consist of the constrained transport method to preserve the divergence-free property of the magnetic field to machine accuracy, coupled to a method of characteristics for the evaluation of electromotive forces and Lorentz forces. Orbital advection is implemented, and an N-body solver is included to simulate planets or stars interacting with the gas. We present our implementation in detail and present a number of widely known tests for comparison purposes. One strength of FARGO3D is that it can run on either graphical processing units (GPUs) or central processing units (CPUs), achieving large speed-up with respect to CPU cores. We describe our implementation choices, which allow a user with no prior knowledge of GPU programming to develop new routines for CPUs, and have them translated automatically for GPUs.

Rab GTPases and the Autophagy Pathway: Bacterial Targets for a Suitable Biogenesis and Trafficking of Their Own Vacuoles Lopez de Armentia, María Milagros; Amaya, Celina; Colombo, Maria Isabel Autophagy is an intracellular process that comprises degradation of damaged organelles, protein aggregates and intracellular pathogens, having an important role in controlling the fate of invading microorganisms. Intracellular pathogens are internalized by professional and non-professional phagocytes, localizing in compartments called phagosomes. To degrade the internalized microorganism, the microbial phagosome matures by fusion events with early and late endosomal compartments and lysosomes, a process that is regulated by Rab GTPases. Interestingly, in order to survive and replicate in the phagosome, some pathogens employ different strategies to manipulate vesicular traffic, inhibiting phagolysosomal biogenesis (e.g., Staphylococcus aureus and Mycobacterium tuberculosis) or surviving in acidic compartments and forming replicative vacuoles (e.g., Coxiella burnetti and Legionella pneumophila). The bacteria described in this review often use secretion systems to control the host?s response and thus disseminate. To date, eight types of secretion systems (Type I to Type VIII) are known. Some of these systems are used by bacteria to translocate pathogenic proteins into the host cell and regulate replicative vacuole formation, apoptosis, cytokine responses, and autophagy. Herein, we have focused on how bacteria manipulate small Rab GTPases to control many of these processes. The growing knowledge in this field may facilitate the development of new treatments or contribute to the prevention of these types of bacterial infections.

Early short-term treatment with neutralizing human monoclonal antibodies halts SHIV infection in infant macaques Hessell, Ann J.; Jaworski, Juan Pablo; Epson, Erin; Matsuda, Kenta; Pandey, Shilpi; Kahl, Christoph; Reed, Jason; Sutton, William F.; Hammond, Katherine B.; Cheever, Tracy A.; Barnette, Philip T.; Legasse, Alfred W.; Planer, Shannon; Stanton, Jeffrey J.; Pegu, Amarendra; Chen, Xuejun; Wang, Keyun; Siess, Don; Burke, David; Park, Byung S.; Axthelm, Michael K; Lewis, Anne; Hirsch, Vanessa M.; Graham, Barney S.; Mascola, John R.; Sacha, Jonah B.; Haigwood, Nancy L. Prevention of mother-to-child transmission (MTCT) of HIV remains a major objective where antenatal care is not readily accessible. We tested HIV-1–specific human neutralizing monoclonal antibodies (NmAbs) as a post-exposure therapy in an infant macaque model for intrapartum MTCT. One-month-old rhesus macaques were inoculated orally with the simian-human immunodeficiency virus SHIVSF162P3. On days 1, 4, 7 and 10 after virus exposure, we injected animals subcutaneously with NmAbs and quantified systemic distribution of NmAbs in multiple tissues within 24 h after antibody administration. Replicating virus was found in multiple tissues by day 1 in animals that were not treated. All NmAb-treated macaques were free of virus in blood and tissues at 6 months after exposure. We detected no anti-SHIV T cell responses in blood or tissues at necropsy, and no virus emerged after CD8+ T cell depletion. These results suggest that early passive immunotherapy can eliminate early viral foci and thereby prevent the establishment of viral reservoirs.

Acerca de los inicios de la divulgación del Psicoanálisis en Argentina: un análisis de escuela para padres; About the beginning of the popularization og Psychoanalysis in Argentina: an analysis of school for parents Savio, Ana Karina En este artículo nos proponemos analizar los tres tomos de Escuela para Padres de Eva Giberti. Buscamos, por un lado, reflexionar sobre el dispositivo enunciativo que allí surge (Maingueneau, 1987, 1999; Amossy, 2005) y, por el otro, rastrear el modo o los modos en que se construye, formula y reformula el saber experto en estos textos (Authier, 1993, 1995). El trabajo ha revelado que la divulgadora/enunciadora no se presenta como una simple mediadora entre el público lector y el saber del experto, sino que, por el contrario, las imágenes que se construyen en torno a su figura y al vínculo con el enunciatario presentan distintos matices y generan diversos efectos de sentido en el entramado discursivo. Por otra parte, se ha advertido que el nuevo saber al que se refieren no se manifiesta como inalcanzable o cerrado a la comunidad psicoanalítica.; In this article, we analyze the three volumes titled Escuela para Padres, written by Eva Giberti. We seek, on the one hand, reflect on the enunciative device (Maingueneau, 1987, 1999; Amossy, 2005) and, on the other, consider the mode or the modes in which it is constructed, formulate and reformulate the expert knowledge in these texts (Authier, 1993, 1995). This study has identified that in these texts the enunciator is not presented as a simple mediator between the public readers and the expert knowledge, but, on the contrary, the images that are constructed around its figure and the relation with the addresses have different nuances and generate various sense effects in the discursive framework. On the other hand, it has concluded that the new knowledge they refer to does not appear as out of reach, closed to the psychoanalytic community.

Nanotoxicological Effects of SiO2 Nanoparticles on Spodoptera frugiperda Sf9 Cells Santo Orihuela, Pablo Luis; Foglia, María Lucía; Targovnik, Alexandra Marisa; Miranda, Maria Victoria; Desimone, Martín Federico The application of silica nanoparticles (NPs) in the biomedical field experienced a great development. Thedriving forces for these and future developments are the possibility to design NPs with homogeneous size and structureamenable to specific grafting. Moreover, it is possible to tune the characteristics of the NPs to meet the requirements ofeach specific cell and desired application. Herein, we analyzed the effect of silica NPs of various sizes and surface chargeon the viability of Spodoptera frugiperda cells (Sf9 cell line) with the aim of extending the knowledge of possible toxicityof the NPs in the environment and development of new tools for insect control. Moreover, these results will also contributeto develop more effective systems for gene vectors delivery and recombinant proteins expression. Bare silica NPs of14 nm, 380 nm and 1430 nm as well as amine-modified silica NPs of 131 nm and 448 nm were obtained by the Stöbermethod. The NPs were characterized by DLS and zeta potential measurements. The cell viability was assessed by theMTT test. It was observed that the 14 nm NPs possess the highest toxic effect. Indeed, after 24h, the viability of the cellsexposed to the lower concentration of NPs (0.12 mg/ml) was about 40% of the value obtained for the control cells not exposedto NPs. Moreover, the exposure to other negative charged NPs also causes a lower activity when compared with thecontrol. Alternatively, lower concentrations of positive charged NPs (i.e.: 0.12 or 0.6 mg/ml) demonstrated to stimulatethe proliferation of the cells and higher concentrations (i.e.: 7.2 mg/ml) did not present significant differences with thecontrol. In conclusion, we have demonstrated that the NPs possess an effect that is highly influenced by the size, chargeand concentration. Although, silica NPs are being used in the biomedical field, these results contribute to further understandingthe risk that could be associated to nanoparticles and how these can be modified in order to meet the requirementsof each desired application.

First Steps in the Aggregation Process of Copolymers Based on Thymine Monomers: Characterization by Molecular Dynamics Simulations and Atomic Force Microscopy Garay, Alberto Sergio; Rodrigues, Daniel Enrique; Fuselli, Antonela; Martino, Debora Marcela; Passeggi, Mario Cesar Guillermo Atomistic molecular dynamic simulations were performed to study thestructure of isolated VBT−VBA (vinylbenzylthymine−vinylbenzyltriethylammoniumchloride) copolymer chains in water at different monomeric species ratios (1:1 and 1:4).The geometric parameters of the structure that the copolymers form in equilibrium together with the basic interactions that stabilize them were determined. Atomic force microscopy (AFM) measurements of dried diluted concentrations of the two copolymers onto highly oriented pyrolytic graphite (HOPG) substrates were carried out to study their aggregation arrangement. The experiments show that both copolymers arrange in fiber-like structures. Comparing the diameters predicted by the simulation results and those obtainedby AFM, it can be concluded that individual copolymers arrange in bunches of two chains, stabilized by contra-ions−copolymer interactions for the 1:1 copolymerization ratio at the ionic strength of our samples. In contrast, for the 1:4 system the individual copolymer chains do not aggregate in bunches. These results remark the relevance of the copolymerization ratio and ionic strength of the solvent in the mesoscopic structure of these materials.

Rheological behavior of concentrated skim milk dispersions as affected by physicochemical conditions: change in pH and CaCl2 addition Olivares, María Laura; Achkar, Natalia Patricia; Zorrilla, Susana Understanding the behavior of casein micelles (CM) in concentrated regimes is critical for the design of dairy unit operations such as drying or evaporation but also it is still scarce. In this work, the effect of the decrease in pH and the addition of a calcium salt on concentrated skim milk dispersions was examined by rheometric measurements at 25 °C. Control samples (S1), samples with a pH of 5.8 (S2), and samples with 0.04 M CaCl2 addition (S3) at different concentrations (40, 45, 48, 50, and 52% w/w) were analyzed through flow curves and oscillatory dynamic data by frequency sweep tests. All samples showed a clear shear thinning non-Newtonian behavior and a large dependence on concentration, dispersions being more fluid for samples S2 and S3. A viscosity model for microgels was used to obtain parameters related to the characteristic structure of systems. It was demonstrated that CM had a similar structure for the different physicochemical systems studied and that the decrease of pH and the addition of salt reduced the dispersion stability due to electrostatic and steric potential energy is depleted. Dynamic data showed that dispersions at the highest concentration had dominant and similar elastic behavior and weak gel character. A transition regime from fluid to gel was observed in samples S2 at 45% w/w. No samples obeyed the Cox-Merz rule. This study allowed gaining more understanding related to the structure of CM systems studied.

Intrinsic Disorder to Order Transitions in the Scaffold Phosphoprotein P from the Respiratory Syncytial Virus RNA Polymerase Complex Noval, María Gabriela; Esperante, Sebastian; Molina, Ivana Gisele; Chemes, Lucia Beatriz; de Prat Gay, Gonzalo Intrinsic disorder is at the center of biochemical regulation and is particularly overrepresented among the often multifunctional viral proteins. Replication and transcription of the respiratory syncytial virus (RSV) relies on a RNA polymerase complex with a phosphoprotein cofactor P as the structural scaffold, which consists of a four-helix bundle tetramerization domain flanked by two domains predicted to be intrinsically disordered. Because intrinsic disorder cannot be reduced to a defined atomic structure, we tackled the experimental dissection of the disorder-order transitions of P by a domain fragmentation approach. P remains as a tetramer above 70 °C but shows a pronounced reversible secondary structure transition between 10 and 60 °C. While the N-terminal module behaves as a random coil-like IDP in a manner independent of tetramerization, the isolated C-terminal module displays a cooperative and reversible metastable transition. When linked to the tetramerization domain, the C-terminal module becomes markedly more structured and stable, with strong ANS binding. Therefore, the tertiary structure in the C-terminal module is not compact, conferring "late" molten globule-like IDP properties, stabilized by interactions favored by tetramerization. The presence of a folded structure highly sensitive to temperature, reversibly and almost instantly formed and broken, suggests a temperature sensing activity. The marginal stability allows for exposure of protein binding sites, offering a thermodynamic and kinetic fine-tuning in order-disorder transitions, essential for the assembly and function of the RSV RNA polymerase complex.

Glial Cell-Elicited Activation of Brain Microvasculature in Response to Brucella abortus Infection Requires ASC Inflammasome-Dependent IL-1β Production Miraglia, Maria Cruz; Franco, Miriam M. Costa; Rodríguez, Ana María; Bellozi, Paula M. Q.; Ferrari, Carina Cintia; Farias, Maria Isabel; Dennis, Vida A.; Barrionuevo, Paula; Oliveira, Antonio C. P. de; Pitossi, Fernando Juan; Kim, Kwang Sik; Delpino, María Victoria; Oliveira, Sergio C.; Giambartolomei, Guillermo Hernan Blood-brain barrier activation and/or dysfunction are a common feature of human neurobrucellosis, but the underlying pathogenic mechanisms are largely unknown. In this article, we describe an immune mechanism for inflammatory activation of human brain microvascular endothelial cells (HBMEC) in response to infection with Brucella abortus Infection of HBMEC with B. abortus induced the secretion of IL-6, IL-8, and MCP-1, and the upregulation of CD54 (ICAM-1), consistent with a state of activation. Culture supernatants (CS) from glial cells (astrocytes and microglia) infected with B. abortus also induced activation of HBMEC, but to a greater extent. Although B. abortus-infected glial cells secreted IL-1β and TNF-α, activation of HBMEC was dependent on IL-1β because CS from B. abortus-infected astrocytes and microglia deficient in caspase-1 and apoptosis-associated speck-like protein containing a CARD failed to induce HBMEC activation. Consistently, treatment of CS with neutralizing anti-IL-1β inhibited HBMEC activation. Both absent in melanoma 2 and Nod-like receptor containing a pyrin domain 3 are partially required for caspase-1 activation and IL-1β secretion, suggesting that multiple apoptosis-associated speck-like protein containing CARD-dependent inflammasomes contribute to IL-1β-induced activation of the brain microvasculature. Inflammasome-mediated IL-1β secretion in glial cells depends on TLR2 and MyD88 adapter-like/TIRAP. Finally, neutrophil and monocyte migration across HBMEC monolayers was increased by CS from Brucella-infected glial cells in an IL-1β-dependent fashion, and the infiltration of neutrophils into the brain parenchyma upon intracranial injection of B. abortus was diminished in the absence of Nod-like receptor containing a pyrin domain 3 and absent in melanoma 2. Our results indicate that innate immunity of the CNS set in motion by B. abortus contributes to the activation of the blood-brain barrier in neurobrucellosis and IL-1β mediates this phenomenon.

Use of phytoplankton assemblages to assess the quality of coastal waters of a transitional ecosystem: Río de la Plata estuary Sathicq, María Belén; Gomez, Nora; Bauer, Delia Elena; Donadelli, Jorge Luis Among the estuarine ecosystems under anthropogenic stress, the Río de la Plata can represent a case study to help identify phytoplanktonic species diagnosing and warning about water quality changes. The freshwater tidal zone on the coast of Argentina is used for several purposes, including recreational and navigational activities and the provision of drinking water. We analyzed the relationship between the abundance of the phytoplanktonic species, changes in water quality (linked to enrichment with nutrients and organic matter) and the land use on the coast of Argentina. A canonical correlation analysis (CCA) allowed us to identify two environmental gradients, one related to anthropogenic activities, where the most influential factors were BOD5, DIN, PO4 3- and DO, and a second gradient related to turbidity and conductivity. The relative abundances of 24 species were significantly correlated with the deterioration of the water quality. This set of tolerant species is mostly composed of taxa considered C-strategists, and the most represented group was the Chlorococcalean algae. The percentage of this group can provide an early warning indicator of the impairment of the water quality; its abundance exceeded 30% at those sites with a bad water quality (reaching 19000 cell mL-1), and were less than 15% (300 cell mL-1) in sites with a good water quality.The use of a reduced group of species constitutes a potential tool for monitoring, complementing another common indicators such as chlorophyll . a or the total density of phytoplankton. Considering that most of these tolerant species are widely distributed it is possible to employ them as a biomonitor in other freshwater zones of temperate estuaries.

Flower reshaping in the transition to hummingbird pollination in Loasaceae subfam. Loasoideae despite absence of corolla tubes or spurs Strelin, Marina Micaela; Benitez-Vieyra, Santiago Miguel; Ackermann, Markus; Cocucci, Andrea Aristides Many angiosperm lineages present transitions from bee to hummingbird pollination. The flower design in most of these lineages includes either corolla tubes or nectar spurs, structures that commonly experienced an elongation with the acquisition of hummingbird pollination. It is proposed that this increases the fit between the bird head and flower structures, and isolates or partially blocks bees from the interaction. But can this transition occur if the ancestral flower design lacks tubes or spurs? Here we focus on the transition from bee to hummingbird pollination in the Loasaceae subfamily Loasoideae. Loasoideae flowers have radial corollas with separated petals; therefore, they do not display corolla tubes nor nectar spurs. These flowers also present a whorl of nectar scales and staminodes, unique to the subfamily, which is involved in flower–pollinator fit and in nectar harvesting. To explore flower shape adaptation to hummingbird pollination, we tested for correspondence between pollinators and flower shape in Loasoideae. In order to achieve this, we first compared the evolutionary history of flower phenotype and pollination mode, and then used stochastic character mapping and geometric-morphometric variables in a comparison of alternative evolutionary models. The results of our study suggest that the transition from bee to bird pollination was accompanied by changes in the shape of the staminodial complex, along with the evolution of relatively closed corollas. Moreover, while bird pollination seems to be the end point in the evolution of pollination syndromes in many angiosperm lineages, rodent pollinated flowers probably evolved from ancestral bird pollinated flowers in Loasoideae. Our findings suggest that the evolution of bird pollinated flowers from ancestral bee pollinated flowers does not require the presence of corolla tubes or spurs, and can take place as long as the flower design includes structures participating in flower–pollinator fit.

Biología reproductiva y citogenética de Distichiaa muscoides (Juncaceae) Gonzáles, Paul; Suni, Mery; Deanna, Rocío; Scaldaferro, Marisel Analía; Castañeda, Elena; Ramírez, Wilfredo; Valencia, Niels; Cano, Asunción El género Distichia Nees & Meyen (Juncaceae) está formado por tres especies nativas de Sudamérica, siendo Distichia muscoides Nees & Meyen la más ampliamente distribuida (Kirschner et al., 2002). Esta especie dioica es el componente principal de los bofedales, ecosistema muy importante de la región altoandina. En este trabajo se estudiaron distintos aspectos biológicos de D. muscoides como: 1) la viabilidad del polen por medio de métodos indirectos de coloración; 2) la receptividad estigmática a través de una prueba con peróxido de hidrógeno; 3) la viabilidad de las semillas mediante su germinación; y 4) sus datos citogenéticos, empleando la técnica de bandeo cromosómico fluorescente CMA/DA/DAPI. Los resultados muestran que las flores estaminadas presentan polen con un porcentaje alto de viabilidad (100%); las flores pistiladas alcanzan la receptividad estigmática una vez que las ramas del estigma desarrollan su máxima longitud (4 mm) y permanecen en este estado al menos durante dos días. El númeropromedio de óvulos por ovario es 34, y el número promedio de semillas por fruto es 25. Las semillas germinaron a partir del día 15, mostrando 92% de germinación y un tiempo promedio de germinación de 18,4 días. La especie posee 2n = 80-84 cromosomas y el bandeo de fluorescencia mostró dos pares de bandas terminales CMA+/DAPI-, asociadas a regiones organizadoras nucleolares (NORs). Se reportan por primera vez datos reproductivos y cariológicos para esta especie.

Distribution of Pyrethroid Resistant Populations of Triatoma infestans in the Southern Cone of South America Bustamante Gomez, Marinely; Gonçalves Diotaiuti, Liléia; Gorla, David Eladio A number of studies published during the last 15 years showed the occurrence of insecticide resistance in Triatoma infestans populations. The different toxicological profiles and mechanisms of resistance to insecticides is due to a genetic base and environmental factors, being the insecticide selective pressure the best studied among the last factors. The studies on insecticide resistance on T. infestans did not consider the effect of environmental factors that may influence the distribution of resistance to pyrethroid insecticides. To fill this knowledge gap, the present study aims at studying the association between the spatial distribution of pyrethroid resistant populations of T. infestans and environmental variables. A total of 24 articles reporting on studies that evaluated the susceptibility to pyrethroids of 222 field-collected T. infestans populations were compiled. The relationship between resistance occurrence (according to different criteria) with environmental variables was studied using a generalized linear model. The lethal dose that kills 50% of the evaluated population (LD 50 ) showed a strong linear relationship with the corresponding resistance ratio (RR 50 ). The statistical descriptive analysis of showed that the frequency distribution of the Log(LD 50 ) is bimodal, suggesting the existence of two statistical groups. A significant model including 5 environmental variables shows the geographic distribution of high and low LD 50 groups with a particular concentration of the highest LD 50 populations over the region identified as the putative center of dispersion of T. infestans.The occurrence of these two groups concentrated over a particular region that coincides with the area where populations of the intermediate cytogenetic group were found might reflect the spatial heterogeneity of the genetic variability of T. infestans, that seems to be the cause of the insecticide resistance in the area, even on sylvatic populations of T. infestans, never before exposed to pyrethroid insecticides, representing natural and wild toxicological phenotypes. The strong linear relationship found between LD 50 and RR 50 suggest RR 50 might not be the best indicator of insecticide resistance in triatomines.

Physiological response and sulphur accumulation in the biomonitor Ramalina celastri in relation to the concentrations of SO2 and NO2 in urban environments Mateos, Ana Carolina; Gonzalez, Claudia M. This study extends the current knowledge regarding the use of different tools for monitoring atmospheric pollution. The chemical response of the lichen Ramalina celastri was evaluated through physiological parameters and sulphur accumulation in relation to the SO2 and NO2 concentrations present in the air at the monitoring sites with different emission sources, in order to assess the atmospheric pollution in urban environments. In this way, it was possible to establish different levels of air quality using simultaneous measurements of gaseous pollutants in the air and of parameters for the exposed biomonitor, as well as to determine the relationship among them and their association with the different emission sources present. Thalli of Ramalina celastri were transplanted at sites with different pollutant emission sources within the city of Córdoba, and simultaneously the concentrations of SO2 and NO2 were measured at the same sampling sites. Pigment content, hydroperoxy conjugated dienes, malondialdehyde and sulphur accumulation were quantified in the lichen and the pollution index was calculated. The results showed that high concentrations of atmospheric SO2 in urban environments can be detected with certainty by measuring sulphur accumulation on the biomonitor. Although this relationship has often been assumed, it has not been confirmed by using simultaneous measurements. This biomonitor allowed different air quality levels to be identified in relation to the concentrations of NO2 and SO2 in Córdoba city. The biomarkers that best reflected the damage caused by pollutants on the lichen were pollution index, hydroperoxy conjugated dienes and malondialdehyde, which revealed a strong association with the most polluted areas in the city (industrial and heavy traffic sites).

Structural Insights into the HWE Histidine Kinase Family: The Brucella Blue Light-Activated Histidine Kinase Domain Rinaldi, Jimena Julieta; Arrar, Mehrnoosh; Sycz, Gabriela; Cerutti, Maria Laura; Berguer, Paula Mercedes; Paris, Gastón; Estrin, Dario Ariel; Marti, Marcelo Adrian; Klinke, Sebastian; Goldbaum, Fernando Alberto In response to light, as part of a two-component system, the Brucella blue light-activated histidine kinase (LOV-HK) increases its autophosphorylation, modulating the virulence of this microorganism. The Brucella histidine kinase (HK) domain belongs to the HWE family, for which there is no structural information. The HWE family is exclusively present in proteobacteria and usually coupled to a wide diversity of light sensor domains. This work reports the crystal structure of the Brucella HK domain, which presents two different dimeric assemblies in the asymmetric unit: one similar to the already described canonical parallel homodimers (C) and the other, an antiparallel non-canonical (NC) dimer, each with distinct relative subdomain orientations and dimerization interfaces. Contrary to these crystallographic structures and unlike other HKs, in solution, the Brucella HK domain is monomeric and still active, showing an astonishing instability of the dimeric interface. Despite this instability, using cross-linking experiments, we show that the C dimer is the functionally relevant species. Mutational analysis demonstrates that the autophosphorylation activity occurs in cis. The different relative subdomain orientations observed for the NC and C states highlight the large conformational flexibility of the HK domain. Through the analysis of these alternative conformations by means of molecular dynamics simulations, we also propose a catalytic mechanism for Brucella LOV-HK.