Two different genomes that produce the same result

Despite differences in genomic sequence, the developmental program of two distantly related Dictyostelium species is remarkably similar

To lend the dead a voice : second-generation German visual art

This dissertation is a study of five second-generation German visual artists (i.e., artists born between 1940 and 1970 who are the descendants of Jewish and Gentile Germans of the Third Reich) who deal with the legacy of the Third Reich in their artwork. Informed by contemporary trauma theory, the project traces how the psychological residue inherited from their parents' Third Reich experience has ingrained itself in the social life of contemporary Jews and Germans, finding expression both directly and obliquely in the works of second-generation artists. It is my conviction that the legacy of the Third Reich must be addressed productively in order to accomplish what psychoanalysis has coined the labour of mourning. Because public discourse around World War II and the Holocaust is still subject to a significant reticence, especially among Jews and Germans, alternate means of communication may be found in visual art production. I conducted personal interviews with selected artists in Canada and Germany, namely Brigitte Radecki, Suse Rumland, Eva Brandl, and Bettina Hoffmann, followed by a thorough theoretical analysis of their work and examination of their personal data. As a second-generation German visual artist, I also included my own work in the study. My study establishes that second-generation German visual artists are in a unique position to contribute to a necessary labour of mourning that was bypassed by their parents' generation and that they approach this difficult task in significant ways. As a visual artist, my studio art practice habitually informs my theoretical investigations. Therefore the first part of this thesis consisted of a series of three solo exhibitions ( Speechless, The Grim Reaper , and 2001 Earth Odyssey ), which were exhibited simultaneously in Montreal in August 2002. They addressed issues of trauma and recovery as experienced by one second-generation artist, with the intent of establishing community and opening new venues for discussion

A produção científica do curso de graduação em odontologia da ufsc: uma análise dos trabalhos de conclusão de curso frente à agenda nacional de prioridades na pesquisa em saúde.

TCC (graduação) - Universidade Federal de Santa Catarina. Centro de Ciências da Saúde. Odontologia.O avanço da produção científica da Odontologia brasileira tornou-se evidente no cenário mundial nas últimas décadas. Entretanto, o aumento na quantidade não significa, necessariamente, maior qualidade. As pesquisas científicas precisam estar relacionadas às demandas da população brasileira. Entende-se que a avaliação desta produção científica frente à expectativa do conhecimento útil para o país solicita uma compreensão estratégica do perfil desta produção. Neste contexto, o presente estudo teve como objetivo analisar a produção científica do curso de graduação em Odontologia UFSC a partir dos Trabalhos de Conclusão de Curso (TCC), relacionando-a à Agenda Nacional de Prioridades de Pesquisa em Saúde (ANPPS). Trata-se de uma pesquisa exploratória descritiva, documental, de abordagem quantitativa, com análise bibliométrica de dados que foram coletados através de um formulário online no Googledocs®, incluindo as seguintes variáveis: título do trabalho; ano de publicação; formato do TCC (monografia/artigo); tipo do trabalho (revisão de literatura/ relato de caso/ pesquisa); área de pesquisa (ciências básicas/ Odontologia em geral/ saúde bucal coletiva e áreas afins/ especialidades odontológicas); TCC incluídos na Agenda de Prioridades em Pesquisa em Saúde; e TCC incluídos no subitem da Agenda de Saúde Bucal. Os resultados foram analisados por meio de estatística descritiva, destacando-se que dos 413 trabalhos, apenas 99 estavam relacionados à ANPPS em SB (n=23,97%), dando conta de 14 dos 17 eixos da ANPPS. Dos 99 TCC com temáticas priorizadas na Agenda, 87 (87,88%) se configuravam como pesquisa. Também a partir do total de TCC analisados, constatou-se que 263 (63,68%) estavam relacionados a uma área temática descrita como de “especialidades odontológicas”, dos quais somente 43 (16,35%) desenvolveram temáticas consideradas prioritárias na Agenda. Por outro lado, na área temática descrita como “saúde coletiva e áreas afins” que correspondeu a apenas 13,08% (n=54) do total de TCC analisados, a maioria (68,52%, n=37) desenvolveu temas considerados prioritários. Conclui-se que o perfil da produção científica no curso de graduação em Odontologia da UFSC ainda não está direcionado às necessidades socialmente mais relevantes, indo de encontro às mudanças preconizadas pelas DCN

Exploitation of Other Social Amoebae by Dictyostelium caveatum

Dictyostelium amoebae faced with starvation trigger a developmental program during which many cells aggregate and form fruiting bodies that consist of a ball of spores held aloft by a thin stalk. This developmental strategy is open to several forms of exploitation, including the remarkable case of Dictyostelium caveatum, which, even when it constitutes 1/10(3) of the cells in an aggregate, can inhibit the development of the host and eventually devour it. We show that it accomplishes this feat by inhibiting a region of cells, called the tip, which organizes the development of the aggregate into a fruiting body. We use live-cell microscopy to define the D. caveatum developmental cycle and to show that D. caveatum amoebae have the capacity to ingest amoebae of other Dictyostelid species, but do not attack each other. The block in development induced by D. caveatum does not affect the expression of specific markers of prespore cell or prestalk cell differentiation, but does stop the coordinated cell movement leading to tip formation. The inhibition mechanism involves the constitutive secretion of a small molecule by D. caveatum and is reversible. Four Dictyostelid species were inhibited in their development, while D. caveatum is not inhibited by its own compound(s). D. caveatum has evolved a predation strategy to exploit other members of its genus, including mechanisms of developmental inhibition and specific phagocytosis

Assaying Rho GTPase–dependent processes in Dictyostelium discoideum

The model organism D. discoideum is well-suited to investigate basic questions of molecular and cell biology, particularly those related to the structure, regulation and dynamics of the cytoskeleton, signal transduction, cell-cell adhesion and development. D. discoideum cells make use of Rho-regulated signaling pathways to reorganize the actin cytoskeleton during chemotaxis, endocytosis and cytokinesis. In this organism the Rho family encompasses 20 members, several belonging to the Rac subfamily, but there are no representatives of the Cdc42 and Rho subfamilies. Here we present protocols suitable for monitoring the actin polymerization response and the activation of Rac upon stimulation of aggregation competent cells with the chemoattractant cAMP, and for monitoring the localization and dynamics of Rac activity in live cells

Predicting the Distribution of Spiral Waves from Cell Properties in a Developmental-Path Model of Dictyostelium Pattern Formation

The slime mold Dictyostelium discoideum is one of the model systems of biological pattern formation. One of the most successful answers to the challenge of establishing a spiral wave pattern in a colony of homogeneously distributed D. discoideum cells has been the suggestion of a developmental path the cells follow (Lauzeral and coworkers). This is a well-defined change in properties each cell undergoes on a longer time scale than the typical dynamics of the cell. Here we show that this concept leads to an inhomogeneous and systematic spatial distribution of spiral waves, which can be predicted from the distribution of cells on the developmental path. We propose specific experiments for checking whether such systematics are also found in data and thus, indirectly, provide evidence of a developmental path

Comparative genome and transcriptome analyses of the social amoeba Acytostelium subglobosum that accomplishes multicellular development without germ-soma differentiation

Background Social amoebae are lower eukaryotes that inhabit the soil. They are characterized by the construction of a starvation-induced multicellular fruiting body with a spore ball and supportive stalk. In most species, the stalk is filled with motile stalk cells, as represented by the model organism Dictyostelium discoideum, whose developmental mechanisms have been well characterized. However, in the genus Acytostelium, the stalk is acellular and all aggregated cells become spores. Phylogenetic analyses have shown that it is not an ancestral genus but has lost the ability to undergo cell differentiation. Results We performed genome and transcriptome analyses of Acytostelium subglobosum and compared our findings to other available dictyostelid genome data. Although A. subglobosum adopts a qualitatively different developmental program from other dictyostelids, its gene repertoire was largely conserved. Yet, families of polyketide synthase and extracellular matrix proteins have not expanded and a serine protease and ABC transporter B family gene, tagA, and a few other developmental genes are missing in the A. subglobosum lineage. Temporal gene expression patterns are astonishingly dissimilar from those of D. discoideum, and only a limited fraction of the ortholog pairs shared the same expression patterns, so that some signaling cascades for development seem to be disabled in A. subglobosum. Conclusions The absence of the ability to undergo cell differentiation in Acytostelium is accompanied by a small change in coding potential and extensive alterations in gene expression patterns

Bursting synchronization in networks with long-range coupling mediated by a diffusing chemical substance

Many networks of physical and biological interest are characterized by a long-range coupling mediated by a chemical which diffuses through a medium in which oscillators are embedded. We considered a one-dimensional model for this effect for which the diffusion is fast enough so as to be implemented through a coupling whose intensity decays exponentially with the lattice distance. In particular, we analyzed the bursting synchronization of neurons described by two timescales (spiking and bursting activity), and coupled through such a long-range interaction network. One of the advantages of the model is that one can pass from a local (Laplacian) type of coupling to a global (all-to-all) one by varying a single parameter in the interaction term. We characterized bursting synchronization using an order parameter which undergoes a transition as the coupling parameters are changed through a critical value. We also investigated the role of an external time-periodic signal on the bursting synchronization properties of the network. We show potential applications in the control of pathological rhythms in biological neural networks.Comment: 13 figure

The Carboxy-Terminal Domain of Dictyostelium C-Module-Binding Factor Is an Independent Gene Regulatory Entity

The C-module-binding factor (CbfA) is a multidomain protein that belongs to the family of jumonji-type (JmjC) transcription regulators. In the social amoeba Dictyostelium discoideum, CbfA regulates gene expression during the unicellular growth phase and multicellular development. CbfA and a related D. discoideum CbfA-like protein, CbfB, share a paralogous domain arrangement that includes the JmjC domain, presumably a chromatin-remodeling activity, and two zinc finger-like (ZF) motifs. On the other hand, the CbfA and CbfB proteins have completely different carboxy-terminal domains, suggesting that the plasticity of such domains may have contributed to the adaptation of the CbfA-like transcription factors to the rapid genome evolution in the dictyostelid clade. To support this hypothesis we performed DNA microarray and real-time RT-PCR measurements and found that CbfA regulates at least 160 genes during the vegetative growth of D. discoideum cells. Functional annotation of these genes revealed that CbfA predominantly controls the expression of gene products involved in housekeeping functions, such as carbohydrate, purine nucleoside/nucleotide, and amino acid metabolism. The CbfA protein displays two different mechanisms of gene regulation. The expression of one set of CbfA-dependent genes requires at least the JmjC/ZF domain of the CbfA protein and thus may depend on chromatin modulation. Regulation of the larger group of genes, however, does not depend on the entire CbfA protein and requires only the carboxy-terminal domain of CbfA (CbfA-CTD). An AT-hook motif located in CbfA-CTD, which is known to mediate DNA binding to A+T-rich sequences in vitro, contributed to CbfA-CTD-dependent gene regulatory functions in vivo