Expansions and contractions of repetitive DNA elements reveal contrasting evolutionary responses to the polyploid genome shock hypothesis in model grasses.

grass species have been selected as model plants for functional genomics of grass crops, and to elucidate the origins of allopolyploidy and perenniality in monocots, due to their small genome sizes and feasibility of cultivation. However, genome sizes differ greatly between diploid or polyploid lineages. We have used genome skimming sequencing data to uncover the composition, abundance, and phylogenetic value of repetitive elements in 44 representatives of the major lineages and cytotypes.

Phylogenomics and Systematics of Overlooked Mesoamerican and South American Polyploid Broad-Leaved Grasses Differentiate sects. and and subgen. and (.).

Allopolyploidy is considered a driver of diversity in subtribe Loliinae. We investigate the evolution and systematics of the poorly studied Mesoamerican and South American polyploid broad-leaved L. species of uncertain origin and unclear taxonomy.

Evolutionary Dynamics of the Repeatome Explains Contrasting Differences in Genome Sizes and Hybrid and Polyploid Origins of Grass Loliinae Lineages.

The repeatome is composed of diverse families of repetitive DNA that keep signatures on the historical events that shaped the evolution of their hosting species. The cold seasonal Loliinae subtribe includes worldwide distributed taxa, some of which are the most important forage and lawn species (fescues and ray-grasses). The Loliinae are prone to hybridization and polyploidization.

Echinococcosis in children: Experience in a tertiary care hospital outside the endemic area.

Echinococcosis is a zoonotic disease that is widely spread across Argentina and worldwide. It is acquired during childhood but it is more common during adulthood. The pediatric population accounts for 10-20% of all cases.

Varicella at "Casa Garrahan", 2008-2013: Assessment of postexposure prophylaxis measures.

Introduction: Casa Garrahan (CG) accommodates children with complex conditions referred nationwide; these children are seen in children's hospitals located in the Autonomous City of Buenos Aires. Varicella is a highly-contagious disease, with attack rates of up to 90% among susceptible individuals. In closed communities, the implementation of outbreak control measures is critical.

Polyphyly, gene-duplication and extensive allopolyploidy framed the evolution of the ephemeral Vulpia grasses and other fine-leaved Loliinae (Poaceae).

The fine-leaved Loliinae is one of the temperate grass lineages that is richest in number of evolutionary switches from perennial to annual life-cycle, and also shows one of the most complex reticulate patterns involving distinct diploid and allopolyploid lineages. Eight distinct annual lineages, that have traditionally been placed in the genus Vulpia and in other fine-leaved ephemeral genera, have apparently emerged from different perennial Festuca ancestors. The phenotypically similar Vulpia taxa have been reconstructed as polyphyletic, with polyploid lineages showing unclear relationships to their purported diploid relatives.

Effectiveness of a program to improve antibiotic use in children hospitalized in a children's tertiary care facility in Argentina.

Introduction: Inadequate antibiotic use is associated with an increased emergence of resistant microorganisms, higher morbidity and mortality rates, and an impact on public health.

Objective: To assess the effectiveness of a program aimed at improving the use of antimicrobials in patients hospitalized at Hospital Garrahan.

Material And Methods: Prospective, longitudinal, before and after study with no control group.

Phylogenetics of tribe Orchideae (Orchidaceae: Orchidoideae) based on combined DNA matrices: inferences regarding timing of diversification and evolution of pollination syndromes.

Background And Aims: Tribe Orchideae (Orchidaceae: Orchidoideae) comprises around 62 mostly terrestrial genera, which are well represented in the Northern Temperate Zone and less frequently in tropical areas of both the Old and New Worlds. Phylogenetic relationships within this tribe have been studied previously using only nuclear ribosomal DNA (nuclear ribosomal internal transcribed spacer, nrITS). However, different parts of the phylogenetic tree in these analyses were weakly supported, and integrating information from different plant genomes is clearly necessary in orchids, where reticulate evolution events are putatively common.

[Reasons for inappropriate prescribing of antibiotics in a high-complexity pediatric hospital].

Objective: Determine the reasons for inappropriate prescription of antibiotics and identify opportunities to improve prescription of these drugs in pediatric patients hospitalized in intermediate and intensive care units.

Methods: A prospective, descriptive longitudinal study was conducted of pediatric patients in intermediate and intensive care units who received parenteral administration of antibiotics, with the exception of newborns, burn unit patients, and surgical prophylaxis patients. A univariate analysis and multiple logistic regression were performed.

Dated historical biogeography of the temperate Loliinae (Poaceae, Pooideae) grasses in the northern and southern hemispheres.

Divergence times and biogeographical analyses have been conducted within the Loliinae, one of the largest subtribes of temperate grasses. New sequence data from representatives of the almost unexplored New World, New Zealand, and Eastern Asian centres were added to those of the panMediterranean region and used to reconstruct the phylogeny of the group and to calculate the times of lineage-splitting using Bayesian approaches. The traditional separation between broad-leaved and fine-leaved Festuca species was still maintained, though several new broad-leaved lineages fell within the fine-leaved clade or were placed in an unsupported intermediate position.

Plastocyanin/cytochrome c6 interchange in Scenedesmus vacuolatus.

Plastocyanin and cytochrome c6 from the green alga Scenedesmus vacuolatus were immunoquantified in cells grown under different concentrations of copper and iron. Plastocyanin expression was constitutive, its synthesis was not significantly affected by iron availability, and increases with copper availability. On the contrary, cytochrome c6 synthesis is repressed by copper, and only residual amounts of the protein were detected at 0.

Development of an ELISA approach for the determination of flavodoxin and ferredoxin as markers of iron deficiency in phytoplankton.

Quantification of the iron-nutritional status of phytoplankton is of great interest not only for the study of oceans but also for fresh waters. Flavodoxin is a small flavoprotein proposed as a marker for iron deficiency, since it is induced as a consequence of iron deprivation, replacing the iron-sulphur protein ferredoxin. Flavodoxin and ferredoxin have been frequently used as markers for determination of iron deficiency in phytoplankton.

Crystal structure determination at 1.4 A resolution of ferredoxin from the green alga Chlorella fusca.

Background: [2Fe-2S] ferredoxins, also called plant-type ferredoxins, are low-potential redox proteins that are widely distributed in biological systems. In photosynthesis, the plant-type ferredoxins function as the central molecule for distributing electrons from the photolysis of water to a number of ferredox-independent enzymes, as well as to cyclic photophosphorylation electron transfer. This paper reports only the second structure of a [2Fe-2S] ferredoxin from a eukaryotic organism in its native form.

Isolation and characterization of two different flavodoxins from the eukaryote Chlorella fusca.

Two different molecular forms of flavodoxin from the green alga Chlorella fusca have been purified to homogeneity and their properties compared. The molecular masses are 22 kDa (flavodoxin I) and 20 kDa (flavodoxin II). Western blots of axenic crude extract show the two bands.