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.     

Expression and functional importance of innate immune receptors by intestinal epithelial cells

Pattern recognition receptors are somatically encoded and participate in the innate immune responses of a host to microbes. It is increasingly acknowledged that these receptors play a central role both in beneficial and pathogenic interactions with microbes. In particular, these receptors participate actively in shaping the gut environment to establish a fruitful life-long relationship between a host and its microbiota. Commensal bacteria engage Toll-like receptors (TLRs) and nucleotide oligomerization domain (NOD)-like receptors (NLRs) to induce specific responses by intestinal epithelial cells such as production of antimicrobial products or of a functional mucus layer. Furthermore, a complex crosstalk between intestinal epithelial cells and the immune system is initiated leading to a mature gut-associated lymphoid tissue to secrete IgA. Impairment in NLR and TLR functionality in epithelial cells is strongly associated with chronic inflammatory diseases such as Crohn’s disease, cancer, and with control of the commensal microbiota creating a more favorable environment for the emergence of new infections.     

Transcriptome analysis of the acoelomate human parasite Schistosoma mansoni

Schistosoma mansoni is the primary causative agent of schistosomiasis, which affects 200 million individuals in 74 countries. We generated 163,000 expressed-sequence tags (ESTs) from normalized cDNA libraries from six selected developmental stages of the parasite, resulting in 31,000 assembled sequences and 92% sampling of an estimated 14,000 gene complement. By analyzing automated Gene Ontology assignments, we provide a detailed view of important S. mansoni biological systems, including characterization of metazoa-specific and eukarya-conserved genes. Phylogenetic analysis suggests an early divergence from other metazoa. The data set provides insights into the molecular mechanisms of tissue organization, development, signaling, sexual dimorphism, host interactions and immune evasion and identifies novel proteins to be investigated as vaccine candidates and potential drug targets.     

Some components of adaptive values of heterozygousDrosophila willistoni from irradiated natural populations

Zusammenfassung Die Analyse einiger Adaptationskomponenten (Häufigkeit des Schlüpfens aus dem Ei, Viabilität und Sterilität) bei einer isolierten natürlichen Population vonDrosophila willistoni, zeigte nach Bestrahlung mit Co 60 verminderte Adaptationswerte, während mehrerer Generationen nach Bestrahlung, mit progressiver Angleichung an das Kontrollniveau in den folgenden Generationen. Jedoch erreichte diese Population während 15 Generationen den Grad der Häufigkeit des Schlüpfens von unbehandelten Populationen nicht.     

Genetic effects of γ-radiation on natural populations ofDrosophila willistoni

Zusammenfassung Eine isolierte natürliche Population vonDrosophila willistoni erhielt während eines Jahres eine beträchtliche Beimischung von F₁-Co 60-bestrahlten Fliegen. Die genetische Analyse ergab, dass die Häufigkeit der letalen und semiletalen Allele nach 5 Generationen rasch wieder auf das Normale sank. Die Frequenz der Letalallele war allerdings noch hoch, gleich hoch wie in der in Massenkultur gehaltenen bestrahlten Zucht. Erst nach 15 Generationen sank sie zum Niveau der natürlichen Kontrollpopulation. Einzelne durch Bestrahlung erhaltene Letalallele blieben in der Population erhalten.

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Work developed (1957–1960) with grants in aid of the Conselho Nacional de Pesquisas (CNP_q: Brazilian Nat. Council of Research) and the Rockefeller Foundation.We acknowledge the constant interest and suggestions of Dr.A. R. Cordeiro in charge of the general planning of the radiation genetics project.     

Systemic Understanding of Coopetitive Behaviour in a Latin American Technological Park

The purpose of this article is to construct a systemic structure to explain the relations subjacent to the coopetitive behaviour observed in a Latin American technological park. The research method is qualitative modelling. The primary research technique is the in-depth interview with park experts. Systemic language organised the speeches. The systemic language uses symbols that represent the elements of a system, such as variables, relations, and feedback loops. Initially, we constructed two essential archetypes that describe how the need for coopetition emerged, triggered by failures in meeting customers´ demands and reduced sales. Then, we built an overall systemic structure relying on the essential archetypes, which explains how the coopetitive strategy emerged in the park. The main conclusion reached by the study is learning and public policies as desirable conditions; failure in meeting customers’ requirements as the trigger; and sustainability, knowledge and resource sharing, mitigation of risks and uncertainties, and increased sales by price reduction, as reinforcing feedback factors. The main contribution of the study is a systemic qualitative model that helps understanding how to implement or manage a coopetitive strategy in a network formed of companies mainly driven by technological factors.