DNA sequence variation of drought-response candidate genes in Austrocedrus chilensis

Background: Austrocedrus chilensis (D. Don) Pic. Ser. et Bizzarri commonly known as Patagonian cypress is a member of the Cupressaceae family, characterized by a high adaptive potential for growing in marginal areas and good timber quality. The species grows over a wide area and under a wide range of rainfall. This study assessed adaptive genetic variation at SNP level in candidate genes involved in response to drought stress. Results: A total of 18 single nucleotide polymorphisms (SNPs) were found among 1,428 bp. Average nucleotide diversity value (\u3c0 = 0.00312) was similar to those previously reported in other Cupressaceae. The Fst average among genes and populations was 0.163 and the lowest differentiation was observed in continuous and humid populations. A number of neutrality tests were applied to find evidence of positive selection in our candidate gene set, but only AcAQP2 gene in Pedregoso and San Ram\uf3n populations revealed significant departures from neutrality with positive values suggesting balancing selection. Conclusions: In this study we report the levels of nucleotide diversity searched in some drought stress candidate genes in Austrocedrus chilensis and the selective factors that may be acting on this species

Selección de “indicadores microbiológicos de calidad del suelo” como tópico generativo para la enseñanza de Microbiología Agrícola en la FCAyF

Se presenta una innovación en el área de Microbiología Agrícola de las Carreras de Ingeniería Agronómica y Forestal, propiciando el “uso de indicadores microbiológicos de calidad del suelo” como “tópico generativo” en el marco de “la enseñanza para la comprensión”. Con la aplicación de esta metodología, se busca concientizar a los alumnos sobre la importancia de la conservación del recurso suelo y su biodiversidad, así como ponerlos en contacto con problemáticas hipotéticas de su futura actividad laboral. Se definieron las Metas de Comprensión, seleccionando los indicadores microbiológicos: determinación del recuento de flora total y grupos funcionales (celulolíticos, amonificadores, nitrificadores), actividad global del suelo empleando técnicas como la evaluación de la respiración y la deshidrogenasa. En base a los datos analizados se observa que la selección de este tópico generativo resultó adecuada para el desarrollo e integración de los contenidos del curso y permitió fomentar en los alumnos una actitud participativa en el proceso de enseñanza-aprendizaje.Eje temático 2: Los cambios e innovaciones en los procesos de formación\na - Alternativas didácticas y experiencias de renovación de la enseñanz

Computed Tomography Measurement of Rib Cage Morphometry in Emphysema

Background: Factors determining the shape of the human rib cage are not completely understood. We aimed to quantify the contribution of anthropometric and COPD-related changes to rib cage variability in adult cigarette smokers. Methods: Rib cage diameters and areas (calculated from the inner surface of the rib cage) in 816 smokers with or without COPD, were evaluated at three anatomical levels using computed tomography (CT). CTs were analyzed with software, which allows quantification of total emphysema (emphysema%). The relationship between rib cage measurements and anthropometric factors, lung function indices, and %emphysema were tested using linear regression models. Results: A model that included gender, age, BMI, emphysema%, forced expiratory volume in one second (FEV1)%, and forced vital capacity (FVC)% fit best with the rib cage measurements (R2  = 64% for the rib cage area variation at the lower anatomical level). Gender had the biggest impact on rib cage diameter and area (105.3 cm2; 95% CI: 111.7 to 98.8 for male lower area). Emphysema% was responsible for an increase in size of upper and middle CT areas (up to 5.4 cm2; 95% CI: 3.0 to 7.8 for an emphysema increase of 5%). Lower rib cage areas decreased as FVC% decreased (5.1 cm2; 95% CI: 2.5 to 7.6 for 10 percentage points of FVC variation). Conclusions: This study demonstrates that simple CT measurements can predict rib cage morphometric variability and also highlight relationships between rib cage morphometry and emphysema

Extremos geográficos de la distribución natural de Austrocedrus chilensis (Cupressaceae) Geographic extremes of the natural range of Austrocedrus chilensis (Cupressaceae)

El "Ciprés de la Cordillera " ( Austrocedrus chilensis (D.Don) Pic. Ser. et Bizzarri) es la conífera nativa de mayor importancia económica de los bosques templados de Argentina. Se han detectado en la bibliografía imprecisiones respecto al rango latitudinal en el que se desarrolla, las que motivaron este estudio. Se determinaron los extremos de ese rango en base a antecedentes bibliográficos, información provista por pobladores y expertos regionales, y reconocimientos en el campo. El extremo septentrional se ubica a los 32º 39' S (Región V de Valparaíso, Chile), y el extremo austral se halla a los 43º 44' S (Provincia de Chubut, Argentina), lo que representa una distancia de unos 1230 km . Esta variación latitudinal y el carácter fragmentario de su distribución natural apoyan la hipótesis de la existencia de ecotipos en la especie.The "Patagonian Cypress" ( Austrocedrus chilensis (D.Don) Pic. Ser. et Bizzarri) is the most economically important native conifer of the temperate forests of Argentina. Some inaccuracy was detected in the bibliography with respect to its latitudinal range, what motivates the present study. The location of the latitudinal extremes was determined based on bibliographic antecedents, local settlers' and experts' information, and field surveys. The northernmost extreme is located at 32º 39' S (Region V of Valparaíso, Chile), while the southernmost extreme at 43º 44' S (Chubut Province, Argentina). This 11 latitudinal grades range represents a distance of 1230 km. This broad latitudinal range and the fragmentary feature of its natural distribution area support the hypothesis of ecotypes for this species

Genetic variation in architectural seedling traits of Patagonian cypress natural populations from the extremes of a precipitation range

• Species distributed along wide environmental ranges are expected to be either plastic or adapted to local optima. The elucidation of which of these alternatives prevails, is crucial in planning breeding and conservation strategies for not yet domesticated species. Austrocedrus chilensis (Cupressaceae) is the most commercially important conifer of the temperate forests of Argentina and the target of a domestication program. A steep precipitation gradient characterizes its Argentinean range. • Variation within and differentiation among four natural populations of this Patagonian cypress representative of two contrasting precipitation regimes (>1300 and 330 mm per y) were assessed by analyzing several morpho/architectural traits in one-year-old seedlings grown in a greenhouse. • Progenies from one of the two xeric populations did not differ from those corresponding to both humid-site populations. The two most variable populations in terms of additive genetic variance belonged to contrasting precipitation regimes. Differentiation among populations was low as measured by each and every variable (average Qst = 0.088). Morphological traits related to the main axis size would have a dubious adaptive meaning. • The results suggest that the Patagonian cypress would have not evolved genetic pools adapted to local optima, and thus it appears to be a phenotypically plastic species, at least regarding growth at juvenile age