Effect of intercalating mutagens on crossing-over inDrosophila melanogaster females

Summary In order to evaluate the effect of several intercalating compounds on crossing-over inDrosophila melanogaster females, acridine orange, acriflavine, chloroquine, ethidium bromide and quinacrine were fed separately to larvae ofy ct f/+++ genotype. Our results show that acridine orange, acriflavine and ethidium bromide increase significantly the recombination frequency at thect-f region and support the view that, for intercalating agents, there is a relationship between clastogenic activity and female recombination induction.     

Design of a System Dynamics Model to Analyze the Styrene Demand in the Brazilian Market

The growth of the petrochemical industry is based on end-user applications such as the automotive and construction sectors, which are the main drivers of the styrene market. However, the use of substitutes for petrochemicals is a reality and creates a competition in the applications of petroleum products. In this sense, this research aimed to design a system dynamics model to evaluate different scenarios, observing the behavior of the styrene demand over time. In the first phase of the project, a greater understanding of the issue was created and a closed loops diagram was elaborated. It was used during the second phase to design an explanatory regression validation model for the styrene demand. In phase three, a visualizing model and scenarios were designed. The scenarios themselves and the results of each scenario were evaluated. The designed and simulated scenarios aimed to evaluate the impact that the use of substitute materials and the variations in gross domestic product cause to the styrene market. The use of system dynamics together with scenario planning was efficient as different strategies for the market could be evaluated based on the simulated scenarios. A critical analysis of the model’s contribution to the decision-making within organizations concludes the study.     

Predicting Recessions with Factor Linear Dynamic Harmonic Regressions

We propose a new framework for building composite leading indicators for the Spanish economy using monthly targeted predictors and small‐scale dynamic factor models. Our leading indicator index, based on the low‐frequency components of four monthly economic variables, is able to predict the onset of the Spanish recessions as well as the gross domestic product (GDP) growth cycles and classical industrial production cycles, both historically and in real time. Also, our leading indicator provides substantial aid in forecasting annual and quarterly GDP growth rates. Using only real data available at the beginning of each forecast period, our indicator one‐step‐ahead forecasts shows substantial improvements over other alternatives. Copyright © 2013 John Wiley & Sons, Ltd.     

Sorting nexin 3 mutation impairs development and neuronal function in <Emphasis Type="Italic">Caenorhabditis elegans</Emphasis>

The sorting nexins family of proteins (SNXs) plays pleiotropic functions in protein trafficking and intracellular signaling and has been associated with several disorders, namely Alzheimer’s disease and Down’s syndrome. Despite the growing association of SNXs with neurodegeneration, not much is known about their function in the nervous system. The aim of this work was to use the nematode Caenorhabditis elegans that encodes in its genome eight SNXs orthologs, to dissect the role of distinct SNXs, particularly in the nervous system. By screening the C. elegans SNXs deletion mutants for morphological, developmental and behavioral alterations, we show here that snx-3 gene mutation leads to an array of developmental defects, such as delayed hatching, decreased brood size and life span and reduced body length. Additionally, ?snx-3 worms present increased susceptibility to osmotic, thermo and oxidative stress and distinct behavioral deficits, namely, a chemotaxis defect which is independent of the described snx-3 role in Wnt secretion. ?snx-3 animals also display abnormal GABAergic neuronal architecture and wiring and altered AIY interneuron structure. Pan-neuronal expression of C. elegans snx-3 cDNA in the ?snx-3 mutant is able to rescue its locomotion defects, as well as its chemotaxis toward isoamyl alcohol. Altogether, the present work provides the first in vivo evidence of the SNX-3 role in the nervous system.     

A high-resolution HLA and SNP haplotype map for disease association studies in the extended human MHC

The proteins encoded by the classical HLA class I and class II genes in the major histocompatibility complex (MHC) are highly polymorphic and are essential in self versus non-self immune recognition. HLA variation is a crucial determinant of transplant rejection and susceptibility to a large number of infectious and autoimmune diseases. Yet identification of causal variants is problematic owing to linkage disequilibrium that extends across multiple HLA and non-HLA genes in the MHC. We therefore set out to characterize the linkage disequilibrium patterns between the highly polymorphic HLA genes and background variation by typing the classical HLA genes and >7,500 common SNPs and deletion-insertion polymorphisms across four population samples. The analysis provides informative tag SNPs that capture much of the common variation in the MHC region and that could be used in disease association studies, and it provides new insight into the evolutionary dynamics and ancestral origins of the HLA loci and their haplotypes.     

Comparing peripheral glial cell differentiation in <Emphasis Type="Italic">Drosophila</Emphasis> and vertebrates

In all complex organisms, the peripheral nerves ensure the portage of information from the periphery to central computing and back again. Axons are in part amazingly long and are accompanied by several different glial cell types. These peripheral glial cells ensure electrical conductance, most likely nuture the long axon, and establish and maintain a barrier towards extracellular body fluids. Recent work has revealed a surprisingly similar organization of peripheral nerves of vertebrates and Drosophila. Thus, the genetic dissection of glial differentiation in Drosophila may also advance our understanding of basic principles underlying the development of peripheral nerves in vertebrates.