The genetics and genomics of Trypanosoma cruzi

Trypanosoma cruzi is a kinetoplastid parasite that causes Chagas disease. Trypanosomes are unusual organisms in many aspects of its genetics and molecular and cellular biology and considered a paradigm of the exception of the rule in the eukaryotic kingdom. The complete genome sequence of T. cruzi was published in 2005, thus, providing a major tool to the understanding of several of his unusual aspects. However, with so many different mechanisms between the parasite and its mammalian host there is still a lack of availability of effective antiparasitic drugs or disease treatments, specially in the chronic phase. This review highlights the fundamentals of the fasci- nating genetics and genomics of T. cruzi with emphasis in the differential mechanisms that could provide interesting therapeutic targets.Fil: Vazquez, Martin Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentin

Guanacos in the Second Component of Túnel I (Beagle Channel). a taphonomic approach

El presente artículo ofrece los resultados del análisis de los restos de guanacos (Lama guanicoe) provenientes del Segundo Componente de Túnel I, emplazado en la margen norte del canal Beagle, particularmente los incluidos en la capa D datada entre 6.400 y 4.500 años AP. Se utiliza un enfoque tafonómico a fin de identificar qué agentes y procesos, y en qué grado, intervinieron en la conformación del conjunto. Con este objetivo en mente se aplica una serie de procedimientos metodológicos y modelos tafonómicos no utilizados previamente en contextos de la región, que a su vez son evaluados en cuanto a su potencial analítico y explicativo en este caso. Se pone especial énfasis en la evaluación de distintas modalidades de cuantificación anatómica y en la aplicación del Modelo de Alto y Bajo Potencial de Supervivencia, las conclusiones han resultado estimulantes para futuras aplicaciones en conjuntos de similares características.En cuanto a las inferencias arqueológicas derivadas de los análisis, se destaca que las cacerías de guanacos se habrían realizado en escala reducida, obteniendo una o pocas presas por evento, las que habrían sido explotadas de forma completa. La representación anatómica diferencial y la frecuencia y variabilidad de huellas antrópicas, entre otras evidencias, sugiere el transporte diferencial de los miembros, el faenamiento intensivo de las presas y la posición terminal de Túnel I en la cadena de explotación de este recurso. Aunque también la dinámica de procesos atricionales, particularmente la acción de carnívoros, habrían tenido una incidencia significativa en la conservación diferencial de elementos.This article provides the results of the analysis of guanaco (Lama guanicoe) remains from Second Component of Tunel I site -northern shore of the Beagle Channel- particularly those included in the D layer (6.400-4.500 years AP). A taphonomic approach is used to identify which agents and processes took part in the formation of the assemblage, and to what degree. With this purpose in mind, a series of methodological procedures and taphonomic models not previously used in this region, are applied and evaluated in terms of its analytical and explanatory potential in this case. Special emphasis is placed on the evaluation of different types of anatomical quantification, and in the application of the Model of High and Low Potential for Survival, the conclusions stimulate future applications in similar feature sets. With respect to archaeological inferences derived from the analysis, it points out that the hunting of guanaco was made on a small scale, obtaining one or a few preys per event which were processed entirely. Differential anatomical representation and the frequency and variability of butchery marks, among other evidence, suggests differential transport of members, the intensive slaughter of the preys and the terminal position of Túnel I in the exploitation chain of this resource. However, also the dynamics of attritional processes, particularly the carnivore's action, would have had a significant impact on the differential preservation of elements.Fil: Vazquez, Martin Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Kn 26, a New Quadrupolar Planetary Nebula

Once classified as an emission line source, the planetary nebula (PN) nature of the source Kn 26 has been only recently recognized in digital sky surveys. To investigate the spectral properties and spatio-kinematical structure of Kn 26, we have obtained high spatial-resolution optical and near-IR narrow-band images, high-dispersion long-slit echelle spectra, and intermediate-resolution spectroscopic observations. The new data reveal an hourglass morphology typical of bipolar PNe. A detailed analysis of its morphology and kinematics discloses the presence of a second pair of bipolar lobes, making Kn 26 a new member of the subclass of quadrupolar PNe. The time-lap between the ejection of the two pairs of bipolar lobes is much smaller than their dynamical ages, implying a rapid change of the preferential direction of the central engine. The chemical composition of Kn 26 is particularly unusual among PNe, with a low N/O ratio (as of type II PNe) and a high helium abundance (as of type I PNe), although not atypical among symbiotic stars. Such an anomalous chemical composition may have resulted from the curtail of the time in the Asymptotic Giant Branch by the evolution of the progenitor star through a common envelope phase.Comment: 9 pages, 5 figures, accepted for publication in A&

Structure, composition and metagenomic profile of soil microbiomes associated to agricultural land use and tillage systems in the Argentine Pampas

Agriculture is facing a major challenge nowadays: to increase crop production for food and energy while preserving ecosystem functioning and soil quality. Argentine Pampas is one of the main world producers of crops and one of the main adopters of conservation agriculture. Changes in soil chemical and physical properties of Pampas soils due to different tillage systems have been deeply studied. Still, not much evidence has been reported on the effects of agricultural practices on Pampas soil microbiomes. The aim of our study was to investigate the effects of agricultural land use on community structure, composition and metabolic profiles on soil microbiomes of Argentine Pampas. We also compared the effects associated to conventional practices with the effects of no-tillage systems. Our results confirmed the impact on microbiome structure and composition due to agricultural practices. The phyla Verrucomicrobia, Plactomycetes, Actinobacteria, and Chloroflexi were more abundant in non cultivated soils while Gemmatimonadetes, Nitrospirae and WS3 were more abundant in cultivated soils. Effects on metabolic metagenomic profiles were also observed. The relative abundance of genes assigned to transcription, protein modification, nucleotide transport and metabolism, wall and membrane biogenesis and intracellular trafficking and secretion were higher in cultivated fertilized soils than in non cultivated soils. We also observed significant differences in microbiome structure and taxonomic composition between soils under conventional and no- tillage systems. Overall, our results suggest that agronomical land use and the type of tillage system have induced microbiomes to shift their life-history strategies. Microbiomes of cultivated fertilized soils (i.e. higher nutrient amendment) presented tendencies to copiotrophy while microbiomes of non cultivated homogenous soils appeared to have a more oligotrophic life-style. Additionally, we propose that conventional tillage systems may promote copiotrophy more than no-tillage systems by decreasing soil organic matter stability and therefore increasing nutrient availability.Fil: Carbonetto, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Agrobiotecnología de Rosario; ArgentinaFil: Rascovan, Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Agrobiotecnología de Rosario; ArgentinaFil: Alvarez, Roberto. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mentaberry, Alejandro Nestor. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Fisiología, Biología Molecular y Celular; ArgentinaFil: Vazquez, Martin Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Agrobiotecnología de Rosario; Argentin

Field trials of an improved cost-effective device for detecting peridomestic populations of Triatoma infestans (Hemiptera: Reduviidae) in rural Argentina

An improved device for detecting peridomestic Triatoma infestans consisting of one-liter recycled Tetra Brik milk boxes with a central structure was tested using a matched-pair study design in two rural areas in Argentina. In Olta (La Rioja), the boxes were installed beneath the thatched roofs and on the vertical wooden posts of each peridomestic structure. After a 5-month exposure, at least one of the recovered boxes detected 88% of the 24 T. infestans-positive sites, and 86% of the 7 negative sites by timed manual collections at baseline. In Amamá (Santiago del Estero), the boxes were paired with the best performing prototype tested before (shelter unit). After 3 months, some evidence of infestation was detected in 89% (boxes) and 79% (shelters) of 18-19 sites positive by timed collections, whereas 19% and 16% of 32 negative sites were positive, respectively. Neither device differed significantly in the qualitative or quantitative collection of every sign of infestation. The installation site did not modify significantly the boxes' sampling efficiency in both study areas. As the total cost of each box was half as expensive as each shelter unit, the boxes are thus the most cost-effective and easy-to-use tool for detecting peridomestic T. infestans currently available.Fil: Vazquez Prokopec, Gonzalo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Ceballos, Leonardo A.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Salomón, Oscar Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Centro Nacional de Diagnóstico e Investigaciones Endemo-epidémicas; ArgentinaFil: Gurtler, Ricardo Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentin