Fate map of zebrafish left-right organizer

The organizer is a ciliated signalling transient organ, responsible for the patterning of embryo tissues during embryonic development. In higher vertebrates, such as mouse and chick, this organizer (the node and the Hensen’s node, respectively) performs dorsalventral and anteriorposterior axis definition, as well as left-right patterning of the internal organs. In lower vertebrates, such as frog and zebrafish, there is a separate specialized organ for left-right purposes called the Gastrocoel Roof Plate (GRP) and Kupffer’s Vesicle (KV), respectively. It is known that mouse and chick organizer cells give rise to structures like floor plate, notochord, hypochord and somites. Frog GRP originates all these but floor plate. In zebrafish, at 13-14 somite stage (ss) the KV finished its left-right patterning but what happens to this organizer’ cells is still poorly studied. This research attempts to understand the fate and behaviour of the KV cells. We followed the fate of KV cells by live imaging and by tight time-courses with fixed larvae. We assessed in detail their proliferative and death profile, as well as cilia length progression from 9-10 ss until 29-30 ss. We conclude that the KV cells mostly follow the evolutionarily conserved fates described for other organizers. These cells mainly incorporate the notochord and hypochord; few cells incorporate the floor plate and the somites. As a novelty, it is also hypothesized that the hypural cell fate may be among the KV cell fates.

IB Middle years programme : global issues . Project organizer 1.

Libro para alumnos del primer curso del Programa de los Años Intermedios (PAI) del Bachillerato Internacional (IB) centrado en el aprendizaje interdisciplinar. Sus contenidos reflejan aspectos clave de la filosofía y el enfoque del programa del BI como la mentalidad internacional y la honestidad académica. Está estructurado en seis lecciones cada una sobre un tema extraído de los Objetivos de Desarrollo del Milenio acordados por Naciones Unidas: erradicación de la pobreza, refugiados e inmigrantes, educación universal, salud y enfermedad, comercio mundial y desarrollo, sostenibilidad del medio ambiente. El acercamiento a cada tema se hace desde distintas materias para estructurar y facilitar el estudio interdisciplinario.

IB Middle years programme : global issues . Project organizer 2.

Libro para alumnos del segundo curso del Programa de los Años Intermedios (PAI) del Bachillerato Internacional (IB) centrado en el aprendizaje interdisciplinar del tema de la agricultura. Sus contenidos reflejan aspectos clave de la filosofía y el enfoque del programa del BI como la mentalidad internacional y la honestidad académica. Está estructurado en seis lecciones cada una sobre un tema extraído de los Objetivos de Desarrollo del Milenio acordados por Naciones Unidas: la pobreza y el hambre, conflictos y la paz, educación universal, salud y enfermedad, comercio mundial y desarrollo, sostenibilidad del medio ambiente. El acercamiento a cada tema se hace desde distintas materias para estructurar y facilitar el estudio interdisciplinario .

IB Middle years programme : global issues . Project organizer 3.

Libro para alumnos del tercer curso del Programa de los Años Intermedios (PAI) del Bachillerato Internacional (IB) centrado en el aprendizaje interdisciplinar. Sus contenidos reflejan aspectos clave de la filosofía y el enfoque del programa del BI como la mentalidad internacional y la honestidad académica. Está estructurado en seis lecciones cada una sobre un tema extraído de los Objetivos de Desarrollo del Milenio acordados por Naciones Unidas (la pobreza y el hambre, conflictos y la paz, educación universal, salud y enfermedad, comercio mundial y desarrollo, sostenibilidad del medio ambiente) en relación con los recursos disponibles en el planeta. El acercamiento a cada tema se hace desde distintas materias para estructurar y facilitar el estudio interdisciplinario.

IB Middle years programme : global issues . Project organizer 4.

Libro para alumnos del cuarto curso del Programa de los Años Intermedios (PAI) del Bachillerato Internacional (IB) centrado en el aprendizaje interdisciplinar. Sus contenidos reflejan aspectos clave de la filosofía y el enfoque del programa del BI como la mentalidad internacional y la honestidad académica. Está estructurado en seis lecciones cada una sobre un tema extraído de los Objetivos de Desarrollo del Milenio acordados por Naciones Unidas (la pobreza y el hambre, conflictos y la paz, educación universal, salud y enfermedad, comercio mundial y desarrollo, sostenibilidad del medio ambiente) en relación con el tema de la población mundial y la superpoblación. El acercamiento a cada tema se hace desde distintas materias para estructurar y facilitar el estudio interdisciplinario.

IB Middle years programme : global issues . Project organizer 5.

Libro para alumnos del quinto curso del Programa de los Años Intermedios (PAI) del Bachillerato Internacional (IB) centrado en el aprendizaje interdisciplinar. Sus contenidos reflejan aspectos clave de la filosofía y el enfoque del programa del BI como la mentalidad internacional y la honestidad académica. Está estructurado en seis lecciones cada una sobre un tema extraído de los Objetivos de Desarrollo del Milenio acordados por Naciones Unidas (la pobreza y el hambre, conflictos y la paz, educación universal, salud y enfermedad, comercio mundial y desarrollo, sostenibilidad del medio ambiente) en relación con la ética, los derechos y la moral. El acercamiento a cada tema se hace desde distintas materias para estructurar y facilitar el estudio interdisciplinario.

Accentuated polymorphism of heterochromatin and nucleolar organizer regions in Astyanax scabripinnis (Pisces, Characidae): tools for understanding karyotypic evolution

Astyanax scabripinnis has been considered a species complex because it presents high karyotypic and morphological variability among its populations. In this work, individuals of two A. scabripinnis populations from different streams in the same hydrographic basin were analyzed through C-banding and AgNOR. Although they present distinct diploid numbers, they show meta and submetacentric chromosome groups highly conserved (numerically and morphologically). Other chromosomal characteristics are also shared by both populations, as the pattern of constitutive heterochromatin distribution (large blocks in the telomeric regions of subtelocentric and acrocentric chromosomes) and some nucleolar chromosomes. Inter-individual variations both in the number and size of heterochromatic blocks, and in the number and localization of NORs were verified in the studied populations, characterizing them as polymorphics for these regions. The mechanisms involved in the dispersion of heterochromatin and NORs through the karyotypes, as well as the possible events related to the generation of polymorphism of those regions are discussed. Furthermore, relationships between these populations and within the context of the scabripinnis complex are also approached.

KARYOTYPE and NUCLEOLUS ORGANIZER REGIONS of Ophisternon aenigmaticum (Teleostei: Synbranchiformes: Synbranchidae) FROM VENEZUELA

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Karyotype plasticity in crickets: Numerical, morphological, and nucleolar organizer region distribution pattern of Anurogryllus sp.

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Multiple nucleolus organizer regions in Leptodactylus mystacinus (Amphibia, Anura) and comments on its systematic position in the L fuscus group based on cytogenetic and molecular analyses

Specimens of Leptodactylus mystacinus from Brazil were karyotyped with conventional and differential staining. The 2n = 22 karyotype is similar to that found for the majority of the Leptodactylus, the karyotypic conservatism also confirmed by the similarity of the replication banding patterns with those previously described. L. mystacinus has a small amount of C-banded heterochromatin, located mainly at the centromeres, although telomeric or interstitial bands have also been noticed. With DA/CMA(3) some chromosome regions showed slightly bright fluorescence, and with DA/DAPI, no particular AT-rich repetitive region was observed. Silver staining showed an extensive inter- and intraindividual variation in the number and position of Ag-positive regions, in 1p, 4p, 8p, 8q, and 11p. Nevertheless, FISH using rDNA probes confirmed only the signals on the short arms of chromosomes 4 and 8 as true NORs. The remaining silver stained regions are probably due to the heterochromatin with some affinity to the Ag-staining. Phylogenetic analysis based on partial cytochrome b sequence revealed that L. mystacinus forms a basal branch, so that the presence of multiple NORs in pairs 4 and 8 in this species indicates an autapomorphy.

Nucleolus organizer regions in Physalaemus cuvieri (Anura, Leptodactylidae), with evidence of a unique case of Ag-NOR variability

We studied ten specimens of Physalaemus cuvieri collected at different localities in Brazil using conventional staining and banding techniques. All specimens had 2n = 22. There were karyotypic variants: distinct patterns in the number and chromosome localization of Ag-NORs as well as in the corresponding secondary constrictions. Preliminary C-banding patterns obtained for specimens From two localities are also suggestive of karyotypic differentiation in P. cuvieri.

Karyotype characterization, constitutive heterochromatin and nucleolus organizer regions of Paranaita opima (Coleoptera, Chrysomelidae, Alticinae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)