Topological Analysis of Small Leucine-Rich Repeat Proteoglycan Nyctalopin

Nyctalopin is a small leucine rich repeat proteoglycan (SLRP) whose function is critical for normal vision. The absence of nyctalopin results in the complete form of congenital stationary night blindness. Normally, glutamate released by photoreceptors binds to the metabotropic glutamate receptor type 6 (GRM6), which through a G-protein cascade closes the non-specific cation channel, TRPM1, on the dendritic tips of depolarizing bipolar cells (DBCs) in the retina. Nyctalopin has been shown to interact with TRPM1 and expression of TRPM1 on the dendritic tips of the DBCs is dependent on nyctalopin expression. In the current study, we used yeast two hybrid and biochemical approaches to investigate whether murine nyctalopin was membrane bound, and if so by what mechanism, and also whether the functional form was as a homodimer. Our results show that murine nyctalopin is anchored to the plasma membrane by a single transmembrane domain, such that the LRR domain is located in the extracellular space

Optimisation of Over-Expression in E. coli and Biophysical Characterisation of Human Membrane Protein Synaptogyrin 1

Progress in functional and structural studies of integral membrane proteins (IMPs) is lacking behind their soluble counterparts due to the great challenge in producing stable and homogeneous IMPs. Low natural abundance, toxicity when over-expressed and potential lipid requirements of IMPs are only a few reasons for the limited progress. Here, we describe an optimised workflow for the recombinant over-expression of the human tetraspan vesicle protein (TVP) synaptogyrin in Escherichia coli and its biophysical characterisation. TVPs are ubiquitous and abundant components of vesicles. They are believed to be involved in various aspects of the synaptic vesicle cycle, including vesicle biogenesis, exocytosis and endocytotic recycling. Even though TVPs are found in most cell types, high-resolution structural information for this class of membrane proteins is still missing. The optimisation of the N-terminal sequence of the gene together with the usage of the recently developed Lemo21(DE3) strain which allows the balancing of the translation with the membrane insertion rate led to a 50-fold increased expression rate compared to the classical BL21(DE3) strain. The protein was soluble and stable in a variety of mild detergents and multiple biophysical methods confirmed the folded state of the protein. Crosslinking experiments suggest an oligomeric architecture of at least four subunits. The protein stability is significantly improved in the presence of cholesteryl hemisuccinate as judged by differential light scattering. The approach described here can easily be adapted to other eukaryotic IMPs

O direito à informação e o (ainda restrito) espaço cidadão no Jornalismo Popular impresso

Este artigo objetiva mostrar como na era da informação o Jornalismo, muitas vezes, negligencia o estímulo ao exercício da cidadania, em especial o Jornalismo realizado pelos meios de Comunicação de grande circulação. Estes veículos, em geral, não priorizam temas que colaboram para a formação e o espírito crítico. A análise será focada nos jornais ditos populares, em especial o Super Notícia, periódico fundado em 2002, que se tornou o veículo impresso mais vendido no país, mas com circulação restrita aos municípios mineiros. A pertinência do assunto se dá já que os periódicos populares apresentam grande circulação e, muitas vezes, são a única fonte de leitura das chamadas classes subalternas. Para o estudo, utilizamos a Análise de Conteúdo. Entendemos que o espaço para o Jornalismo Comunitário é restrito, enquanto há ênfase em assuntos relacionados com o crime, os astros de TV e o futebol. No entanto, é preciso buscar este espaço e não apenas ficar no campo da crítica

A tale of agriculturalists and hunter-gatherers: Exploring the thrifty genotype hypothesis in native South Americans

Objectives: To determine genetic differences between agriculturalist and hunter-gatherer southern Native American populations for selected metabolism-related markers and to test whether Neel's thrifty genotype hypothesis (TGH) could explain the genetic patterns observed in these populations. Materials and Methods: 375 Native South American individuals from 17 populations were genotyped using six markers (APOE rs429358 and rs7412; APOA2 rs5082; CD36 rs3211883; TCF7L2 rs11196205; and IGF2BP2 rs11705701). Additionally, APOE genotypes from 39 individuals were obtained from the literature. AMOVA, main effects, and gene-gene interaction tests were performed. Results: We observed differences in allele distribution patterns between agriculturalists and hunter-gatherers for some markers. For instance, between-groups component of genetic variance (FCT) for APOE rs429358 showed strong differences in allelic distributions between hunter-gatherers and agriculturalists (p = 0.00196). Gene-gene interaction analysis indicated that the APOE E4/CD36 TT and APOE E4/IGF2BP2 A carrier combinations occur at a higher frequency in hunter-gatherers, but this combination is not replicated in archaic (Neanderthal and Denisovan) and ancient (Anzick, Saqqaq, Ust-Ishim, Mal'ta) hunter-gatherer individuals. Discussion: A complex scenario explains the observed frequencies of the tested markers in hunter-gatherers. Different factors, such as pleotropic alleles, rainforest selective pressures, and population dynamics, may be collectively shaping the observed genetic patterns. We conclude that although TGH seems a plausible hypothesis to explain part of the data, other factors may be important in our tested populations.Fil: Reales, Guillermo. Universidade Federal do Rio Grande do Sul; BrasilFil: Rovaris, Diego L.. Universidade Federal do Rio Grande do Sul; BrasilFil: Jacovas, Vanessa C.. Universidade Federal do Rio Grande do Sul; BrasilFil: Hünemeier, Tábita. Universidade de Sao Paulo; BrasilFil: Sandoval, José R.. Universidad de San Martín de Porres. Facultad de Medicina Humana; PerúFil: Salazar Granara, Alcibiades. Universidad de San Martín de Porres. Facultad de Medicina Humana; PerúFil: Demarchi, Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Antropología de Córdoba. Universidad Nacional de Córdoba. Facultad de Filosofía y Humanidades. Instituto de Antropología de Córdoba; ArgentinaFil: Tarazona Santos, Eduardo. Universidade Federal de Minas Gerais; BrasilFil: Felkl, Aline B.. Universidade Federal do Rio Grande do Sul; BrasilFil: Serafini, Michele A.. Universidade Federal do Rio Grande do Sul; BrasilFil: Salzano, Francisco M.. Universidade Federal do Rio Grande do Sul; BrasilFil: Bisso Machado, Rafael. Universidad de la República; UruguayFil: Comas, David. Universitat Pompeu Fabra; EspañaFil: Paixão Côrtes, Vanessa R.. Universidade Federal da Bahia; BrasilFil: Bortolini, Maria Catira. Universidade Federal do Rio Grande do Sul; Brasi