Cross-neutralization of the coagulant activity of Crotalus durissus terrificus venom from the northeast of Argentina by bivalent bothropic antivenom Rodríguez, Juan Pablo; Gay, Claudia Carolina; Fusco, Luciano Sebastian; Gauna Pereira, María del Carmen; Acosta, Ofelia Cristina; Leiva, Laura Cristina Ana Cross-neutralization of Crotalus durissus terrificus venom coagulant activity was tested using bivalent horse antivenom against Bothrops alternatus and Bothrops diporus venoms. Our in vitro and in vivo experiments showed that bothropic antivenom neutralizes the thrombin-like activity of crotalic snake venom and this cross-reaction was demonstrated by immunoassays either with whole venom or a purified thrombin-like enzyme. These results suggest common antigenic properties and, consequently, similar molecular structure among venom thrombin-like enzymes. Besides, they provide information that could be further used in the development of new antivenom formulations.

Ultra-sensitive electrochemical immunosensor using analyte peptidomimetics selected from phage display peptide libraries Arevalo, Fernando Javier; González Techera, Andrés; Zon, María Alicia; González Sapienza, Gualberto; Fernández, Héctor Immunosensors for small analytes have been a great addition to the analytical toolbox due to their high sensitivity and extended analytical range. In these systems the analyte is detected when it competes for binding to the detecting antibody with a tracer compound. In this work we introduce the use of phage particles bearing peptides that mimic the target analyte as surrogates for conventional tracers. As a proof of concept, we developed a magneto-electrochemical immunosensor (EI) for the herbicide molinate and compare its performance with conventional formats. Using the same anti-molinate antibody and phage particles bearing a molinate peptidomimetic, the EI performed with an IC 50 of 0.15ngmL -1 (linear range from 4.4×10 -3 to 10ngmL -1). Compared to the conventional ELISA, the EI was faster (minutes), performed with a much wider linear range, and the detection limit that was 2500-fold lower. The EI produced consistent measurements and could be successfully used to assay river water samples with excellent recoveries. By using the same EI with a conventional tracer, we found that an important contribution to the gain in sensitivity is due to the filamentous structure of the phage (9×1000nm) which works as a multienzymatic tracer, amplifying the competitive reaction. Since phage-borne peptidomimetics can be selected from phage display libraries in a straightforward systematic manner and their production is simple and inexpensive, they can contribute to facilitate the development of ultrasensitive biosensors.

Bioestratigrafía de conodontes del Darriwiliano medio (Ordovícico) de Argentina: La Formación Las Aguaditas, Precordillera Central; Biostratigraphy of Middle Darriwilian (Ordovician) conodonts from Argentina: Las Aguaditas Formation, Central Precordillera Heredia, Susana Emma Se recuperaron elementos del género Eoplacognathus de muestras de la Formación Las Aguaditas aflorante en el río de Las Chacritas, provincia de San Juan, Argentina. Estos depósitos de calizas oscuras son grainstones oscuros, packstones y wackestones y representan facies de rampa carbonática distal. Los conodontes guía Eoplacognathuspseudoplanus (Viira) y Eoplacognathus suecicus Bergström documentan las Zonas de E. pseudoplanus y de E. suecicus indicando una edad darriwiliana media para los niveles portadores de conodontes en la Formación Las Aguaditas. Se realiza una evaluación de los antecedentes sobre el registro fósil del género Eoplacognathus en la Precordillera Argentina. Por último, se propone el uso del esquema de biozonas de conodontes del Darriwiliano medio de Báltica para la Precordillera Argentina.; Several P elements of Eoplacognathus were recovered from samples collected in Las Aguaditas Formation, Las Chacritas river section, San Juan Province, Argentina. These dark grainstones, packstones, and wackestones represent distal carbonate rampfacies. The key conodonts Eoplacognathus pseudoplanus (Viira) and Eoplacognathus suecicus Bergström, document the Eoplacognathus pseudoplanus and the E. suecicus Zones pointing out middle Darriwilian age for the conodont–bearing strata in Las Aguaditas Formation. The species E. suecicus is recorded here for first time in the Argentine Precordillera. An evaluation of the record of this middle Darriwilian conodont genus in the Precordillera is presented here. Finally, the use of the middle Darriwilian Baltic conodont chart is proposed for the Argentine Precordillera.

Checklist and updated distribution of Protoneuridae from Brazil Pessacq, Pablo; Santos, Tatiana Chrysostomo; Costa, Janira Martins Protoneuridae are represented in the neotropics by 16 genera and 117 species, of which 64 species in 12 genera are known to occur in Brazil. Most of them are known only from the original descriptions or isolated records. During 2009 the Protoneuridae collection of MNRJ was revised; 2800 specimens were studied, belonging to 40 species in nine genera. As a result, the distribution of 25 species is extended, including 50 new records for several states and three new records for the country: Epipleoneura lamina Williamson, Protoneura woytkowskii Gloyd, and Psaironeura remissa (Calvert). The widest distributions are shown by Neoneura sylvatica Hagen in Selys, Epipleoneura venezuelensis Rácenis, and Epipleoneura metallica Rácenis, which are also recorded from the highest number of states: 11 and eight respectively.Additionally, the distribution of most species within previously recorded states is extended.

On the orientation of fibres in structural members fabricated with self compacting fibre reinforced concrete Zerbino, Raul Luis; Tobes, Juan Manuel; Bossio, Maria Eugenia; Giaccio, Graciela Marta The incorporation of fibres into concrete produces important benefits, mainly on the residual load-bearing capacity. These improvements depend on the type, content and orientation of the fibres, being a strong relationship between the number of fibres in the fracture surfaces and the post peak parameters. Although the fibres could be homogeneously distributed after mixing, the casting and compaction processes can significantly affect the fibre distribution and orientation, and consequently the mechanical performance of the material. In the case of Fibre Reinforced Self Compacting Concrete (FR-SCC) the existence of significant flow and wall effects may influence fibre orientation. This paper analyzes the fibre orientation in thin structural elements cast with FR-SCC and its effects on the residual mechanical properties. A slab of 0.90 × 1.80 × 0.09 m, a wall of 0.50 × 2.00 × 0.08 m, and a beam of 0.15 × 0.15 × 2.50 m were selected as representative elements where different concrete flow conditions take place. A strong heterogeneity in the orientation of the fibres was found. The fibre orientation varied with the flow rate and with the wall effect; the thickness of the elements or the proximity to the bottom of the moulds appeared as important variables. It was demonstrated that in thin elements the residual mechanical properties can be quite different when diverse zones and/or directions of the structural elements are considered. © 2011 Elsevier Ltd. All rights reserved.

Electrostatic self-assembly of hierarchical porous carbon microparticles Balach, Juan Manuel; Bruno, Mariano Martín; Cotella, Nelson Gustavo; Acevedo, Diego Fernando; Barbero, César Alfredo Hierarchical porous carbon microparticles (HPCMs) are produced by milling and sieving porous monolithic carbon, which was obtained by carbonization of a resorcinol-formaldehyde gel in the presence of surfactant as a pore stabilizer. The obtained HPCMs has a surface area of 536 m2 g-1 and maximum specific capacitance and areal capacitance, measured at slow scan rates, of 194 F g-1 and 152 mF cm-2 respectively. Moreover, the carbon surface remains accessible at 100 mV s-1 with large values of specific capacitance (154 F g-1) and areal capacitance (121 mF cm-2), making the material suitable for fast supercapacitors. The HPCMs are then built into electrostatic self-assembled (ESA) adsorbed layers by sequential immersion of a planar electrode in HPCMs dispersions and a cationic polyelectrolyte. Using soluble redox molecules, it is possible to detect the finite (inside the pores) and semi-infinite (outer surface) diffusion of redox species. The specific capacitance of the HPCMs could be increased up to 5 times (to ca. 900 F g-1 in acid media) by adsorption of naphthoquinone molecules on the carbon surface. Using the ESA process, it is possible to build a layer with three different quinones in a single electrode. The specific capacitance of those layers is more than 4 times higher and maintained nearly constant in a wide range of potential.

In Situ Evaluation of Tensile Properties of Heat-Affected Zones From Welded Steel Pipes Castelluccio, G. M.; Yawny, Alejandro Andres; Perez Ipiña, Juan Elias; Ernst, H. A. Currently, measuring the local tensile strength in inhomogeneous materials is not standardised, nor accepted techniques are available despite such technique would be beneficial in a variety of technological applications. Thus, this work introduces an innovative method for assessing stress-strain properties at a sub-millimeter scale and illustrates the potential of the technique by evaluating the strength of a sub-region in the HAZ from welded steels pipes. The method employs a fully instrumented stage inside a scanning electron microscope that stretches small tensile specimens (2.0 mm × 0.5 mm cross-section, 12.5 mm gage length) while registering detailed images of the deformed region. The specimens, cut from full-scale welds, include in their gage length weld metal, base metal and HAZ and have an 85 Îm period grid of evaporated lead on their surface to visualise the deformation. Upon straining, local strain is determined by correlating sequential images of the specimen surface with an open source code for particle image velocimetry. The calculated local strain within the HAZ and the load values recorded during testing are converted into a local stress-strain response. The results for two different heat inputs agree with usual, but indirect and less accurate assessments procedures, including local hardness measurements and notched bar testing.

Environmental effects of ozone depletion and its interactions with climate change: Progress report, 2011 Andrady, A. L.; Aucamp, P. J.; Austin, Amy Theresa; Bais, A. F.; Ballaré, C. L.; Björn, L. O.; Bornman, J. F.; Caldwell, M.; Cullen, A. P.; Erickson, D. J.; de Gruijl, F. R.; Häder, D. P.; Helbling, Eduardo Walter; Ilyas, M.; Longstreth, J.; Lucas, R; Mckenzie, L.; Madronich, S.; Norval, N.; Paul, N. D.; Redhwi, H. H.; Robinson, S.; Shao, M.; Solomon, K. R.; Sulzberger, B.; Takizawa, Y.; Tang, X.; Torikai, A.; van der Leun, J. C.; Williamson, C. E.; Wilson, S. R.; Worrest , R. C.; Zepp, R. G. The parties to the Montreal Protocol are informed by three panels of experts. One of these is the Environmental Effects Assessment Panel (EEAP), which deals with two focal issues. The first focus is the effects of increased UV radiation on human health, animals, plants, biogeochemistry, air quality, and materials. The second focus is on interactions between UV radiation and global climate change and how these may affect humans and the environment. When considering the effects of climate change, it has become clear that processes resulting in changes in stratospheric ozone are more complex than believed previously. As a result of this, human health and environmental problems will be longer-lasting and more regionally variable. Like the other panels, the EEAP produces a detailed report every four years; the most recent was published in 2010 (Photochem. Photobiol. Sci., 2011, 10, 173-300). In the years in between, the EEAP produces less detailed and shorter progress reports, which highlight and assess the significance of developments in key areas of importance to the parties. The next full quadrennial report will be published in 2014-2015.

Sunflower root growth regulation: the role of jasmonic acid and its relation with auxins Corti Monzón, Georgina de la Paz; Pinedo, Marcela Lilian; Lamattina, Lorenzo; de la Canal, Laura Jasmonates are lipid-derived hormones that act as signal molecules in abiotic and biotic stresses and influence several aspects of plant growth and development. In this work we have investigated the effect of jasmonic acid (JA) on the root architecture of Helianthus annuus seedlings and if JA and auxins interact to modulate the growth of the primary root (PR) and lateral roots (LR). The addition of lM concentrations of JA to the growing medium of sunflower seedlings decreased the growth of the PR and LR, and also reduced the number of LR. Moreover, treatment with ibuprofen, an inhibitor of JA synthesis, increased PR and LR root length causing a deep effect on root architecture. Hence, not only exogenous but also the endogenous JA regulates sunflower root growth. Microscopic analysis showed that the application of JA reduces the cortex cell length and the estimated cell production rate in root meristem while ibuprofen only affects the cell elongation. A possible interaction between JA and auxins to regulate root growth was further analyzed. We show that JA produced its phenotype even in the presence of reduced levels of auxin generated by treatment with an auxin transport inhibitor. Besides, the auxin produced its phenotype even when ibuprofen was applied. In conclusion, JA may induce primary and lateral root growth inhibition in sunflower by an auxin-independent pathway.

Short term impact of artisanal dredges in a Patagonian mussel fishery: Comparisons with commercial diving and control sites Narvarte, Maite Andrea; González, Raul Alberto Candido; Medina, Alonso Ismael; Avaca, Maria Soledad; Ginsberg, Silvia Susana; Aliotta, Salvador Mussels in the San Matías Gulf fishery are targeted using artisanal dredges and diving. The main objective of this study was to assess the direct impact of artisanal dredging on the biota and sediments, and to compare the composition of the catches and the individual damage induced by fishing between dredging and commercial diving. The experimental design included samplings from dredge catches, dredge tracks, control sites and commercial diving. According to their damage level, individuals were scored as undamaged, lightly damaged and severely damaged. Sediment characteristics were analyzed using coring samples and traps. Damage of mussels, mostly corresponding to the severely damaged category, was less than 5% both in samples from dredging and diving. Conversely, mean damage of the main bycatch species (sea urchins and ophiuroids) was 75 and 65% in samples from dredging and diving respectively, being most of the individuals lightly damaged. Considering also the catch sample composition of both fishing methods, dredging affected relatively more individuals than diving. Although sediment removal in dredged areas was three times higher than that in non-dredged ones, mean grain size and gravel percentage of sea floor sediments showed subtle differences between them.

Efecto de los metales sobre microcrustáceos de agua dulce. Avances metodológicos y potencialidad de cladóceros y copépodos como organismos test; Effects of metals on freshwater microcrustaceans. Metodological advances and potentiality of cladocerans and copepods as test organisms Gutierrez, Marìa Florencia; Gagneten, Ana María El incremento de los metales en los cuerpos de agua dulce a causa de las actividades antropogénicas genera importantes alteraciones sobre la biota. Esta revisión analiza los efectos adversos de varios metales de relevancia ecotoxicológica sobre los microcrustáceos zooplanctónicos (cladóceros y copépodos), los avances experimentales en esta línea y las ventajas de cada grupo como organismos test. En general, la necesidad de obtener indicadores más sensibles y representativos que los tradicionales, promovió lineamientos hacia estudios subcrónicos, interspecíficos y multigeneracionales. Por otra parte, la tendencia actual hacia el estudio de mezclas de sustancias y los efectos indirectos permite adquirir una visión más integral del problema. El impacto sobre las poblaciones es muy variable, dependiendo de la naturaleza del metal, las características del medio, el tiempo de exposición, las condiciones de cultivo y aspectos genéticos. Sin embargo, la mayoría de los trabajos se centran en pocas especies, dejando vacancias en el conocimiento de las representantes de cada región particular. Si bien algunos atributos de los cladóceros y copépodos como el tamaño, la morfología y el rol ecológico los tornan buenos indicadores, las diferencias en el desarrollo, reproducción y estrategias de perpetuación confieren ventajas a un grupo sobre otro.; The increase of metals in fresh water systems due to anthropogenic activities cause important alterations on the biota. The present review analyze the adverse effects of various metals of ecotoxicological relevance on microcrustaceans zooplankton species (cladocerans and copepods), the experimental advances and the advantages of each group as test organisms. In general, the need to obtain more sensitive and representative indicators than the tradicional ones leads to subchronic, interespecific and multigenerational studies. Additionally, the analysis of mixtures as well as their indirect effects allows to acquire more integral knowledges of the impact of contaminants. The toxic effects are different, depending on the nature of metals, the physicochemical characteristics of the water, exposutre time and genetic traits. However, most works are focused on few species, leading vacant areas on the knowledge of the representatives of every particular region. Despite some cladocerans and copepods atributes make them good bioindicators (size, morphology and ecological role), differences of development, reproduction and perpetuation strategies bring advantages to one group on another.

Natural polyphenols may ameliorate damage induced by copper overload Arnal, Nathalie; Tacconi, Maria Josefa; Marra, Carlos Alberto The effect of the simultaneous exposure to transition metals and natural antioxidants frequently present in food is a question that needs further investigation. We aimed to explore the possible use of the natural polyphenols caffeic acid (CA), resveratrol (RES) and curcumin (CUR) to prevent damages induced by copper-overload on cellular molecules in HepG2 and A-549 human cells in culture. Exposure to 100 μM/24. h copper (Cu) caused extensive pro-oxidative damage evidenced by increased TBARS, protein carbonyls and nitrite productions in both cell types. Damage was aggravated by simultaneous incubation with 100 μM of CA or RES, and it was also reflected in a decrease on cellular viability explored by trypan blue dye exclusion test and LDH leakage. Co-incubation with CUR produced opposite effects demonstrating a protective action which restored the level of biomarkers and cellular viability almost to control values. Thus, while CA and RES might aggravate the oxidative/nitrative damage of Cu, CUR should be considered as a putative protective agent. These results could stimulate further research on the possible use of natural polyphenols as neutralizing substances against the transition metal over-exposure in specific populations such as professional agrochemical sprayers and women using Cu-intrauterine devices.

Adjusting to trade policy: Evidence from U.S. antidumping duties on Vietnamese catfish Brambilla, María Irene; Porto, Guido Gustavo; Tarozzi, Alessandro In 2003, after claims of dumping, the United States imposed heavy tariffs on Vietnamese catfish, which led to a collapse of imports. We use panel data to explore household responses in the catfish-producing Mekong delta between 2002 and 2004 and find that income growth was significantly slower among households relatively more involved in catfish farming in 2002. This is explained by a relative decline in both catfish income and revenues from other miscellaneous farm activities. Labor supply did not adjust, most likely because of off-farm employment limitations. Households more exposed to the shock reduced the share of investment assigned to catfish while substituting into agriculture.

Determination of enantiomeric composition of ibuprofen in pharmaceutical formulations by partial least-squares regression of strongly overlapped chromatographic profiles Osorio Grisales, Jaiver; Arancibia, Juan Alberto; Castells, Cecilia Beatriz Marta; Olivieri, Alejandro Cesar In this report, we demonstrate how chiral liquid chromatography combined with multivariate chemometric techniques, specifically unfolded-partial least-squares regression (U-PLS), provides a powerful analytical methodology. Using U-PLS, strongly overlapped enantiomer profiles in a sample could be successfully processed and enantiomeric purity could be accurately determined without requiring baseline enantioresolution between peaks. The samples were partially enantioseparated with a permethyl-β-cyclodextrin chiral column under reversed-phase conditions. Signals detected with a diode-array detector within a wavelength range from 198 to 241nm were recorded, and the data were processed by a second-order multivariate algorithm to decrease detection limits. The R-(-)-enantiomer of ibuprofen in tablet formulation samples could be determined at the level of 0.5mgL-1 in the presence of 99.9% of the S-(+)-enantiomorph with relative prediction error within ±3%.

Breeding biology of the White-rumped Swallow (Tachycineta leucorrhoa; Hirundinidae) in a wetland: A comparative approach Lorenzón, Rodrigo Ezequiel; Quiroga, Martin Anibal We studied the reproductive biology of the White-rumped Swallow (Tachycineta leucorrhoa) in a colony of 50 nests boxes located in a wetland of the Paraná River, Santa Fe, Argentina between 2004 and 2006. The nest boxes were checked regularly and reproductive parameters, as well as morphological data of eggs and nestlings, were recorded. The species had an average clutch size of 4.7 eggs whose volumes and weight means were 2.04 cm 3 and 2.17 g. respectively. The incubation period averaged 15.9 days and decreased with the clutch size. The mean nestling period was 23.8 days. Clutch size, number of nestlings per nest and the nestling period decreased with the advance of the breeding seasons, while the incubation time increased. Breeding parameters showed a similarity with those reported for the population from Chascomús site, although the eggs were 5% heavier, the incubation period took one more day and the reproductive success was also higher. With the closely related species Tachycineta meyeni, the studied species showed a lower clutch size. Finally, considering another closely related species Tachycineta bicolor, the White-rumped Swallow showed the reproductive life history traits characteristic of species in the southern hemisphere. We provide new information for this species nesting on wetlands, a fact that contributes to the understanding of changes in the life history of the Tachycineta genus along the American continent.

PFT1, the MED25 subunit of the plant Mediator complex, promotes flowering through CONSTANS dependent and independent mechanisms in Arabidopsis Iñigo, Sabrina; Alvarez, Mariano J.; Strasser, Bárbara; Califano, Andrea; Cerdan, Pablo Diego Two aspects of light are very important for plant development: the length of the light phase or photoperiod and the quality of incoming light. Photoperiod detection allows plants to anticipate the arrival of the next season, whereas light quality, mainly the red to far-red ratio (R:FR), is an early signal of competition by neighbouring plants. phyB represses flowering by antagonising CO at the transcriptional and post-translational levels. A low R:FR decreases active phyB and consequently increases active CO, which in turn activates the expression of FT, the plant florigen. Other phytochromes like phyD and phyE seem to have redundant roles with phyB. PFT1, the MED25 subunit of the plant Mediator complex, has been proposed to act in the light-quality pathway that regulates flowering time downstream of phyB. However, whether PFT1 signals through CO and its specific mechanism are unclear. Here we show that CO-dependent and -independent mechanisms operate downstream of phyB, phyD and phyE to promote flowering, and that PFT1 is equally able to promote flowering by modulating both CO-dependent and -independent pathways. Our data are consistent with the role of PFT1 as an activator of CO transcription, and also of FT transcription, in a CO-independent manner. Our transcriptome analysis is also consistent with CO and FT genes being the most important flowering targets of PFT1. Furthermore, comparison of the pft1 transcriptome with transcriptomes after fungal and herbivore attack strongly suggests that PFT1 acts as a hub, integrating a variety of interdependent environmental stimuli, including light quality and jasmonic acid-dependent defences.

Sylvester's double sums: an inductive proof of the general case Krick, Teresa Elena Genoveva; Szanto, Agnes In 1853, Sylvester introduced a family of double sum expressions for two finite sets of indeterminates and showed that some members of the family are essentially the polynomial subresultants of the monic polynomials associated with these sets. In 2009, in a joint work with C. D’Andrea and H. Hong we gave the complete description of all the members of the family as expressions in the coefficients of these polynomials. More recently, M.-F. Roy and A. Szpirglas presented a new and natural inductive proof for the cases considered by Sylvester. Here we show how induction also allows to obtain the full description of Sylvester’s double-sums.

Dispositivo interactivo luminoso como recurso didáctico para la mejor comprensión del concepto acido-base en química general; Interactive Lighting Device as a Teaching Resource for the Better Comprehension of the Acid-Base Concept in General Chemistry Matkovic, Silvana Raquel; Briand, Laura Estefania El presente trabajo aborda la creación de un recurso didáctico que consiste en un dispositivo interactivo luminoso, de sencilla construcción, que complementará a una parte experimental. Se propone utilizarlo para ayudar al alumno a correlacionar su funcionamiento con el proceso de cambio de color observado al interaccionar un indicador ácido- base con una sustancia ácida o alcalina, y utilizarlo para introducir el modelo experto con el cual se enseña en el ámbito académico dicha interacción. Este dispositivo, consta de dos partes que al ponerse en contacto cierran un circuito que enciende una luz que a su vez produce una modificación en el color del recipiente que la contiene. En definitiva esta propuesta involucra una parte experimental que utiliza sustancias naturales y de uso diario junto al uso de un dispositivo luminoso, de tipo interactivo para modelar la interacción molecular característica de un indicador ácido-base.; A teaching resource is constructed with the aim of helping student to better comprehend the acid-base concept in general chemistry, in particular the process of color change that is observed when an acid-base indicator reacts with acid or basic species. The proposal involves an interactive lighting device easy to build. The device lights when its two parts are in contact closing an electric circuit. Therefore it has a certain color when both parts are in contact that differs from the color of the when they are apart. Additionally, the contact of natural dyes with everyday domestic substances is described as a complementary experimental section. The interactive lighting device is a teaching resource that allows correlating the interaction of a chemical species with the change of color of an acid-base indicator.

Renormalization: The observable-state model Ardenghi, Juan Sebastian; Castagnino, Mario Alberto G. J. The usual mathematical formalism of quantum field theory is not rigorous because it contains divergences that can only be renormalized by nonrigorous mathematical methods. So we present a method of subtraction of divergences using the formalism of decoherence. This is achieved by replacing the standard renormalization method by a projector on a well defined Hilbert subspace. In this way a list of problems of the standard formalism disappears while the physical results of quantum field theory remain valid. From its own nature, this formalism can be also used in nonrenormalizable theories.

Archaea Isolates from five hypersaline environments in Argentinean Puna Maldonado, Marcos Javier; Farias, Maria Eugenia The objective of this study was isolate and study halophilic archaea in five hypersaline environments from the Argentinean Puna. Puna is a unique natural area covering northern Chile, western Bolivia, central and southern Peru and north-western Argentina (NOA). These environments are characterized by extreme conditions where salt concentration is very high, near saturation (up to 4 M or 25%), low oxygen tension, large daily air temperature fluctuations, ranging from 20°C during the day to −40°C at night, high UV incidence, high arsenic concentrations and oligotrophy. There is not much information about halophilic archaea in Argentina. The water samples were collected from five different wetlands: Antofalla lake (Catamarca), Socompa lake (Salta), Tolar Grande “Sea eye” (Salta), Pocitos salt flat (Salta) and Llullaillaco salt flat (Salta). These lakes are located above 3500 masl. The samples were cultivated in 6 ws medium for 7 days at 37ºC. 32 strains were isolates. The isolates corresponded to genera Halorubrum, Haloarcula and Halomicrobium. Pigments from the isolates were extracted with methanol. The identification of pigments was based on absorbance spectra. The absorbance was measured at wavelength range 200-800 nm. The most were carotenoids pigments with the highest absorption peak at 492 nm. Plasmid DNA was isolated by using a modified method of Anderson and McKay and the QIAprep® Spin Miniprep Kit (QIAGEN). Ten of the isolates contain plasmids with sizes ranging from 1.5 kb to 5 kb approximately. The presence of plasmids in Archaea from hypersaline environments apparently is a widespread phenomenon. For UV resistance qualitative analysis were plated 5 ul of dilutions between 10-1 and 10-7 in drop form, on 1.5% agar (w/v). The plates were exposed 1 to 13 hours to UV – B light. Then the plates were incubated inverted for 7 days at 37 °C. All the strain had resistance to UV - B light.