The effects of climate change on the distribution of South American antbirds (Thamnophilus punctatus complex) as affected by niche divergences and contact zone interactions between species

Several studies have shown that climatic change has been accelerating due to human activities, leading to dramatic effects on biodiversity. Modeling studies describe how species have reacted in the past to climatic change, and this information can help us to understand the degree of biotic susceptibility to current and future climatic change. This work aims to determine the effects of past, current and future climatic changes on the geographic distribution of the species complex Thamnophilus punctatus, a bird clade widely distributed across Neotropical dry forests. We also investigate if species that are phylogenetically similar have comparable climatic niches and, consequently, can be expected to respond similarly to climatic change. For this purpose, we calculated similarity, niche overlap, equivalence and genetic distance between all species, modeling their geographic distributions during the Last Glacial Maximum (LGM) as well as under current conditions and future (2050-2080) scenarios. Our results indicate that there are differences in responses to climatic changes from the LGM to the present among the five species of the T. punctatus complex and that the niches in the measured dimensions are not conserved among the studied species. We therefore suggest that the adequate environmental space of taxa of a widely distributed lineage can be shaped in distinct way, regardless of how closely related their species are or how much their niches overlap. Competitive exclusion in zones of contact is an important factor determining the geographical range of the species of the Thamnophilus punctatus complex, particularly for the very closely related species T. sticturus, T. pelzelni and T. ambiguus.Peer reviewe

Evolutionary history of the Pectoral Sparrow Arremon taciturnus : evidence for diversification during the Late Pleistocene

We focus on reconstructing a spatiotemporal scenario of diversification of a widespread South American species, the Pectoral Sparrow Arremon taciturnus (Aves: Passerellidae). This species is widely distributed in both the humid and the dry forests of South America and therefore provides an interesting model for understanding the connection between different biomes of South America. We examined nucleotide sequences of the mitochondrial genes Cytochrome b (cyt-b) and NADH subunit 2 (ND2) from 107 specimens, and one nuclear marker (intron 7 of the beta-fibrinogen gene) from a subset of samples collected across the distribution ranges of A. t. taciturnus and A. t. nigrirostris. Six major lineages were recovered in the phylogenies that displayed high levels of variance of allele frequencies and corresponded to distinct geographical locations. The estimation of divergence times provided evidence that diversification of the six lineages of the Pectoral Sparrow occurred throughout the Late Pleistocene across major cis-Andean biomes and Amazonian interfluves. Our dataset for A. taciturnus provides further evidence that rivers in Amazonia constitute barriers promoting allopatric speciation, with occasional sharing of alleles among lineages, particularly those with adjacent distributions.Peer reviewe

Citron melon peel flours: drying kinetics and physicochemical evaluation

In the utilization of citron melon (Citrullus lanatus var. citroides), it is necessary to deal with a large amount of residues constituted by the peels. These materials commonly discarded can be fully utilized, since they are a source of nutrients. The peels contain not only fibers, but also proteins, sugars and minerals, which, after drying, are concentrated to values that make them interesting for various uses, including for the enrichment of flours or combinations to prepare bakery products. Therefore, the drying of the peels, besides enabling the conservation and storage at room temperature, expands the forms of use and the possibilities of entering the production chain. This study aimed to characterize physico-chemically and determine drying kinetics, effective diffusivity, activation energy and thermodynamic properties of citron melon peels at different drying temperatures. The peels were dried in an oven with forced air circulation, in a thin layer, at temperatures of 60, 70, 80 and 90 °C. With the data collected in the drying, the drying kinetic curves were constructed and eleven mathematical models were fitted to the experimental data. The dried material was crushed in a knife mill and characterized for physicochemical parameters. Midilli model resulted in the best fits, followed by Page and Approximation of Diffusion models. Effective diffusivity increased with drying temperature; activation energy was obtained from the Arrhenius equation and was equal to 8.18 kJ/mol. Enthalpy and entropy were reduced with increased temperature, while Gibbs free energy increased

APTIDÃO FÍSICA RELACIONADA À SAÚDE DE CRIANÇAS E ADOLESCENTES DO ESTADO DO RIO GRANDE DO SUL

O estudo da aptidão física relacionada à saúde (ApFRS) em crianças e adolescentes éjustificado pelo fato de seus componentes terem relação com várias doenças. Dessa forma, havendo um diagnóstico precoce da debilidade de um ou mais de seus componentes, existe a possibilidade, mediante ações efetivas, de o indivíduo voltar a ter níveis satisfatórios de aptidão física no que diz respeito à saúde. Com base nisso, os objetivos do presente estudo foram (a) analisar o desenvolvimento da ApFRS de crianças e adolescentes gaúchas, verificando as possíveis diferenças entre sexos e idades; e (b) determinar a ocorrência de crianças e adolescentes que se situam respectivamente abaixo, dentro ou acima das zonas saudáveis de aptidão física (ZSApF) e de massa corporal (ZSMC). Para tal, contamos com 6.794 crianças e adolescentes de 10 cidades do estado do Rio Grande do Sul. As variáveis estudadas foram resistência geral (medida pelo teste de corrida/caminhada de 9 min); índice de massa corporal (IMC); força/resistência abdominais (medidas pelo teste de abdominais em 1 min); e flexibilidade (medida pelo teste de sentar e alcançar). Os critérios de referência (ZSApF eZSMC) adotados para as avaliações da ApFRS correspondem aos utilizados pelo Projeto Esporte Brasil

Projeto cisternas fertilizadas: um recorte sobre agroecologia, tecnologias sociais e gênero/ Fertilized cisternas project: a highlight on agroecology, social technologies and gender

O Semiárido brasileiro por muito tempo foi visto pelo prisma do combate à seca, o que culminou em políticas ineficientes para resolução de problemas advindos da pouca oferta de água. Por muito tempo o desenvolvimento de técnicas e o gerenciamento dessas ficou a cargo dos chefes da família, onde as mulheres ficavam de fora do processo. O presente trabalho buscou realizar uma reflexão sobre as tecnologias sociais de convivência com o semiárido, a agroecologia e a questão de gênero. A tecnologia aqui discutida, desenvolvida a partir da parceria de diferentes setores (universidades e movimentos sociais), é a de reuso de água, que busca aumentar a oferta de água para produção agrícola dos moradores do assentamento Hipólito, no município de Mossoró (RN). O reuso de água apresenta benefícios sociais, ambientais e econômicos, que se pretende concretizá-los a partir da implementação dessa prática no referido assentamento. O reuso aqui retratado não se reduz ao aumento da oferta de água, mas e refere a uma proposta de resiliência às atividades dos agricultores e agricultoras familiares e, principalmente, ao envolvimento das mulheres no processo de implementação dessa tecnologia, contribuindo para a emancipação social dessas

Studying nanotoxic effects of CdTe quantum dots in Trypanosoma cruzi

Semiconductor nanoparticles, such as quantum dots (QDs), were used to carry out experiments in vivo and ex vivo with Trypanosoma cruzi. However, questions have been raised regarding the nanotoxicity of QDs in living cells, microorganisms, tissues and whole animals. The objective of this paper was to conduct a QD nanotoxicity study on living T. cruzi protozoa using analytical methods. This was accomplished using in vitro experiments to test the interference of the QDs on parasite development, morphology and viability. Our results show that after 72 h, a 200 μM cadmium telluride (CdTe) QD solution induced important morphological alterations in T. cruzi, such as DNA damage, plasma membrane blebbing and mitochondrial swelling. Flow cytometry assays showed no damage to the plasma membrane when incubated with 200 μM CdTe QDs for up to 72 h (propidium iodide cells), giving no evidence of classical necrosis. Parasites incubated with 2 μM CdTe QDs still proliferated after seven days. In summary, a low concentration of CdTe QDs (2 μM) is optimal for bioimaging, whereas a high concentration (200 μM CdTe) could be toxic to cells. Taken together, our data indicate that 2 μM QD can be used for the successful long-term study of the parasite-vector interaction in real time

Chagasic Thymic Atrophy Does Not Affect Negative Selection but Results in the Export of Activated CD4+CD8+ T Cells in Severe Forms of Human Disease

Extrathymic CD4+CD8+ double-positive (DP) T cells are increased in some pathophysiological conditions, including infectious diseases. In the murine model of Chagas disease, it has been shown that the protozoan parasite Trypanosoma cruzi is able to target the thymus and induce alterations of the thymic microenvironment and the lymphoid compartment. In the acute phase, this results in a severe atrophy of the organ and early release of DP cells into the periphery. To date, the effect of the changes promoted by the parasite infection on thymic central tolerance has remained elusive. Herein we show that the intrathymic key elements that are necessary to promote the negative selection of thymocytes undergoing maturation during the thymopoiesis remains functional during the acute chagasic thymic atrophy. Intrathymic expression of the autoimmune regulator factor (Aire) and tissue-restricted antigen (TRA) genes is normal. In addition, the expression of the proapoptotic Bim protein in thymocytes was not changed, revealing that the parasite infection-induced thymus atrophy has no effect on these marker genes necessary to promote clonal deletion of T cells. In a chicken egg ovalbumin (OVA)-specific T-cell receptor (TCR) transgenic system, the administration of OVA peptide into infected mice with thymic atrophy promoted OVA-specific thymocyte apoptosis, further indicating normal negative selection process during the infection. Yet, although the intrathymic checkpoints necessary for thymic negative selection are present in the acute phase of Chagas disease, we found that the DP cells released into the periphery acquire an activated phenotype similar to what is described for activated effector or memory single-positive T cells. Most interestingly, we also demonstrate that increased percentages of peripheral blood subset of DP cells exhibiting an activated HLA-DR+ phenotype are associated with severe cardiac forms of human chronic Chagas disease. These cells may contribute to the immunopathological events seen in the Chagas disease

Integrin α8β1 regulates adhesion, migration and proliferation of human intestinal crypt cells via a predominant RhoA/ROCK-dependent mechanism

Background. Integrins are transmembrane αβ heterodimer receptors that function as structural and functional bridges between the cytoskeleton and ECM (extracellular matrix) molecules. The RGD (arginine-glycine-aspartate tripeptide motif)-dependent integrin α8β1 has been shown to be involved in various cell functions in neuronal and mesenchymal-derived cell types. Its role in epithelial cells remains unknown