Effects of hypoxia on buoyancy control and the development of lordosis in physostomous and physoclistous fish species

Solid state NMR/Biophysical Organic Chemistr

Expression analysis of the family of 14-3-3 proteins in zebrafish development

Animal sciencesMicrobial Biotechnolog

Gene expression profiling of the long-term adaptive response to hypoxia in the gills of adult zebrafish

Animal science

A critical role for myoglobin in zebrafish development

The globin family, including hemoglobin, myoglobin, neuroglobin and cytoglobin, plays an important role in oxygen storage and delivery. Myoglobin has been shown to be necessary for cardiac function during development, but no information is currently available on the developmental regulation of myoglobin gene expression during embryogenesis. In this study, we used whole mount in situ hybridization to visualize myoglobin mRNA expression during zebrafish development. Our results show for the first time the spatial and temporal gene expression pattern of myoglobin during embryogenesis. Myoglobin was expressed as a maternal RNA and ubiquitous expression was observed until the end of gastrulation. At later stages of development, we discovered novel expression domains for myoglobin, including several nonmuscular ones. Environmental stresses, like low oxygen tension (hypoxia) can lead to a developmental delay in zebrafish embryos. We show here that hypoxic stress induces myoglobin expression in skeletal muscle cells of anterior somites and in the dorsal aorta of zebrafish larvae. Finally, we analyzed the role of myoglobins in development by targeted gene knock-down. Silencing myoglobin in zebrafish embryos with gene-specific morpholinos led to a dose dependent curvature, vascular defects, enlarged pericardia and reduction of the gut. In conclusion, our results indicate that myoglobin plays a crucial role in zebrafish development and is important for angiogenesis and gut development. © 2009 UBC Press

Italiani alta la testa! : la presenza del fascismo a São Paulo (1920-1940)

La tesi si prefigge lo scopo di analizzare tra il 1920 e il 1945, da un lato quale fu il sistema di propaganda del fascismo a Sao Paulo e, dall'altro quale l'impatto di quest'ultimo sulla comunità immigrata, non dimenticando di tracciare i lineamenti dell'atteggiamento del Governo brasiliano di fronte al regime italiano. Allo scopo di analizzare quali furono i mezzi utilizzati dal fascismo per la creazione di strutture di partito o di associazioni ad esso strettamente correlate e, quale lo sforzo e i meccanismi per tentare di tenere sotto controllo le diverse forme di aggregazione e vita della comunità (associazioni, giornali, scuole), è stato svolto un lavoro di consultazione della documentazione presente in taluni archivi italiani (dell'Archivio Centrale dello Stato e dell'Archivio Storico del Ministero degli Esteri di Roma, facendo riferimento soprattutto ai documenti presenti nei fondo Apsu-Asmae, Mcp e Mcp-Nupie )e brasiliani (Arquivo Publico do Estado de Sao Paulo, e gli Archivi delle società sportive Esperia e Palestra Italia) e di parte della stampa della collettività italiana e brasiliana pubblicata a Sao Paulo. A partire da questa documentazione si è cercato di mettere in luce quale fu la risposta degli italiani residenti a Sao Paulo nei confronti del regime di Mussolini tenendo presente il diverso atteggiamento che questi ebbero a seconda del periodo storico; da qui la necessità di prendere in esame un periodo di tempo che abbraccia l'intero ventennio fascista, visti i mutamenti e la differente percezione che della diffusione del fascismo si ha tra gli anni venti e trenta del XX secolo. Infatti, tralasciando quanti, ferventi sostenitori di Roma e del Duce si iscrissero la partito, la diffusione del fascismo come rigeneratore dell'orgoglio etnico seguì una parabola ascendente tra il 1920, gli inizi del 1930 e la seconda metà del 1930 per poi mutare ridiscendere durante gli anni della II Guerra mondiale. A cornice di ciò si è resa necessaria una panoramica storica del Brasile di quegli anni, la salita al potere di Getulio Vargas e la creazione del progetto di restaurazione e sviluppo dell'idea nazionale, fattori che, uniti alla determinate influenza statunitense, si rivelarono fondamentali nelle relazioni tra il paese del subcontinente e l'Italia e nell'atteggiamento che il governo brasiliano tenne nei confronti dei migranti. L'atteggiamento di negatività verso gli immigrati italiani dopo l'emanazione dell'Esado Novo e in particolare dopo l'entrata in guerra del Brasile al fianco degli alle Alleati, si giustificava con la credenza dell'esistenza di una quinta colonna nel territorio brasiliano. Di qui la necessità di analizzare la differenza tra le paure del governo e la reale diffusione degli ideali totalitari, tedeschi e, soprattutto italiani, a partire dal 1937. Periodo di ricerca trascorso in Argentina e Brasile. Durante il periodo di tre mesi, dal 4 luglio al 4 ottobre 2007, trascorso in Argentina e Brasile la dott.sa Zega ha lavorato su tre differenti tipologie di fonti: -Ricerche d'archivio svolta presso l'Archivo General del Ministerio de Relaciones Exteriores y Culto di Buenos Aires, l'Archivo de la Direccion de Migraciones, l'Arquivo DEOPS/SP presso Arquivo Publico do Estado de Sao Paulo, e gli Archivi delle società sportive Esperia e Palestra Italia. -Consultazione di alcuni giornali pubblicati dalla collettività italiana a Sao Paulo e Buenos Aires: Fanfulla(SP), Pasquino Coloniale(SP), Mattino d'Italia(Bs. As), Patria degli Italiani(Bs. As). -Ricerca bibliografica finalizzata a conoscere gli ultimi testi pubblicati sull'argoment

Zebrafish cypher is important for somite formation and heart development.

Mammalian CYPHER (Oracle, KIA0613), a member of the PDZ-LIM family of proteins (Enigma/LMP-1, ENH, ZASP/Cypher, RIL, ALP, and CLP-36), has been associated with cardiac and muscular myopathies. Targeted deletion of Cypher in mice is neonatal lethal possibly caused by myopathies. To further investigate the role of cypher in development, we have cloned the zebrafish orthologue. We present here the gene, domain structure, and expression pattern of zebrafish cypher during development. Cypher was not present as a maternal mRNA and was absent during early development. Cypher mRNA was first detected at the 3-somite stage in adaxial somites, and as somites matured, cypher expression gradually enveloped the whole somite. Later, cypher expression was also found in the heart, in head and jaw musculature, and in the brain. We further identified 13 alternative spliced forms of cypher from zebrafish heart and skeletal muscle tissue, among them a very short form containing the PDZ domain but lacking the ZM (ZASP-like) motif and the LIM domains. Targeted gene knock-down experiments using cypher antisense morpholinos led to severe defects, including truncation of the embryo, deformation of somites, dilatation of the pericardium, and thinning of the ventricular wall. The phenotype could be rescued by a cypher form, which contains the PDZ domain and the ZM motif, but lacks all three LIM domains. These findings indicate that a PDZ domain protein is important for normal somite formation and in normal heart development. Treatment of zebrafish embryos with cyclopamine, which disrupts hedgehog signaling, abolished cypher expression in 9 somite and 15-somite stage embryos. Taken together, our data suggest that cypher may play a role downstream of sonic hedgehog, in a late stage of somite development, when slow muscle fibers differentiate and migrate from the adaxial cells

Transcriptome analysis of the response to chronic constant hypoxia in zebrafish hearts

Insufficient blood supply during acute infarction and chronic ischemia leads to tissue hypoxia which can significantly alter gene expression patterns in the heart. In contrast to most mammals, some teleost fishes are able to adapt to extremely low oxygen levels. We describe here that chronic constant hypoxia (CCH) leads to a smaller ventricular outflow tract, reduced lacunae within the central ventricular cavity and around the trabeculae and an increase in the number of cardiac myocyte nuclei per area in the hearts of two teleost species, zebrafish (Danio rerio) and cichlids (Haplochromis piceatus). In order to identify the molecular basis for the adaptations to CCH, we profiled the gene expression changes in the hearts of adult zebrafish. We have analyzed over 15,000 different transcripts and found 376 differentially regulated genes, of which 260 genes showed increased and 116 genes decreased expression levels. Two notch receptors (notch-2 and notch-3) as well as regulatory genes linked to cell proliferation were transcriptionally upregulated in hypoxic hearts. We observed a simultaneous increase in expression of IGF-2 and IGFbp1 and upregulation of several genes important for the protection against reactive oxygen species (ROS). We have identified here many novel genes involved in the response to CCH in the heart, which may have potential clinical implications in the future. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00360-007-0201-4) contains supplementary material, which is available to authorized users

Activation of p42 Mitogen-activated Protein Kinase (MAPK), but not c-Jun NH(2)-Terminal Kinase, Induces Phosphorylation and Stabilization of MAPK Phosphatase XCL100 in Xenopus Oocytes

Dual-specificity protein phosphatases are implicated in the direct down-regulation of mitogen-activated protein kinase (MAPK) activity in vivo. Accumulating evidence suggests that these phosphatases are components of negative feedback loops that restore MAPK activity to low levels after diverse physiological responses. Limited information exists, however, regarding their posttranscriptional regulation. We cloned two Xenopus homologs of the mammalian dual-specificity MAPK phosphatases MKP-1/CL100 and found that overexpression of XCL100 in G2-arrested oocytes delayed or prevented progesterone-induced meiotic maturation. Epitope-tagged XCL100 was phosphorylated on serine during G2 phase, and on serine and threonine in a p42 MAPK-dependent manner during M phase. Threonine phosphorylation mapped to a single residue, threonine 168. Phosphorylation of XCL100 had no measurable effect on its ability to dephosphorylate p42 MAPK. Similarly, mutation of threonine 168 to either valine or glutamate did not significantly alter the binding affinity of a catalytically inactive XCL100 protein for active p42 MAPK in vivo. XCL100 was a labile protein in G2-arrested and progesterone-stimulated oocytes; surprisingly, its degradation rate was increased more than twofold after exposure to hyperosmolar sorbitol. In sorbitol-treated oocytes expressing a conditionally active ΔRaf-DD:ER chimera, activation of the p42 MAPK cascade led to phosphorylation of XCL100 and a pronounced decrease in the rate of its degradation. Our results provide mechanistic insight into the regulation of a dual-specificity MAPK phosphatase during meiotic maturation and the adaptation to cellular stress