Search results for " Nonmammalian"
showing 10 items of 126 documents
Antagonistic roles for Ultrabithorax and Antennapedia in regulating segment-specific apoptosis of differentiated motoneurons in the Drosophila embryo…
2008
The generation of morphological diversity among segmental units of the nervous system is crucial for correct matching of neurons with their targets and for formation of functional neuromuscular networks. However, the mechanisms leading to segment diversity remain largely unknown. We report here that the Hox genes Ultrabithorax (Ubx) and Antennapedia (Antp) regulate segment-specific survival of differentiated motoneurons in the ventral nerve cord of Drosophilaembryos. We show that Ubx is required to activate segment-specific apoptosis in these cells, and that their survival depends on Antp. Expression of the Ubx protein is strongly upregulated in the motoneurons shortly before they undergo a…
Ems and Nkx6 are central regulators in dorsoventral patterning of the Drosophila brain
2009
In central nervous system development, the identity of neural stem cells (neuroblasts) critically depends on the precise spatial patterning of the neuroectoderm in the dorsoventral (DV) axis. Here, we uncover a novel gene regulatory network underlying DV patterning in the Drosophila brain, and show that the cephalic gap gene empty spiracles (ems) and the Nk6 homeobox gene (Nkx6) encode key regulators. The regulatory network implicates novel interactions between these and the evolutionarily conserved homeobox genes ventral nervous system defective (vnd), intermediate neuroblasts defective (ind) and muscle segment homeobox (msh). We show that Msh cross-repressively interacts with Nkx6 to sust…
Identity, origin, and migration of peripheral glial cells in the Drosophila embryo.
2008
Glial cells are crucial for the proper development and function of the nervous system. In the Drosophila embryo, the glial cells of the peripheral nervous system are generated both by central neuroblasts and sensory organ precursors. Most peripheral glial cells need to migrate along axonal projections of motor and sensory neurons to reach their final positions in the periphery. Here we studied the spatial and temporal pattern, the identity, the migration, and the origin of all peripheral glial cells in the truncal segments of wildtype embryos. The establishment of individual identities among these cells is reflected by the expression of a combinatorial code of molecular markers. This allows…
Role of en and novel interactions between msh, ind, and vnd in dorsoventral patterning of the Drosophila brain and ventral nerve cord
2010
AbstractSubdivision of the neuroectoderm into discrete gene expression domains is essential for the correct specification of neural stem cells (neuroblasts) during central nervous system development. Here, we extend our knowledge on dorsoventral (DV) patterning of the Drosophila brain and uncover novel genetic interactions that control expression of the evolutionary conserved homeobox genes ventral nervous system defective (vnd), intermediate neuroblasts defective (ind), and muscle segment homeobox (msh). We show that cross-repression between Ind and Msh stabilizes the border between intermediate and dorsal tritocerebrum and deutocerebrum, and that both transcription factors are competent t…
Localization of mitochondrial Hsp56 chaperonin during sea urchin development.
2001
We have previously demonstrated that Paracentrotus lividus nuclear genome encodes for the heat shock inducible chaperonin homolog Hsp 56 (1) and that the mature protein is localized in the mitochondrial matrix (2). In this paper we report that constitutive Hsp56 is maternally inherited, in fact it is present in the in unfertilized eggs, and that it has a perinuclear specific localization during cleavage. In the later stages both the constitutive and the heat shock inducible chaperonin has a specific territorial distribution. Moreover following heat shock, the Hsp56 appears in the cytoplasm and in the postmitochondrial supernatant beside the mitochondrial fraction.
Phosphoproteinphosphatase activity in sea urchin embryos
1964
Si e studiata l'attivita fosfoproteinfosfatasica in omogenati totali di uova ed embrioni diParacentrotus lividus e diArbacia lixula. La reazione ha un optimum a pH acido, e stimolata da K+ e Na+ ed e inibita da Ca++ e Mg++. L'attivita enzimatica aumenta tra la fecondazione e lo stadio a 64 blastomeri; in seguito rimane costante fino a blastula con mesenchima; quindi generalmente decresce.
Aggregation of cells isolated from vegetalized and animalized sea urchin embryos
1963
Blastule diParacentrotus lividus trattate con LiCl (vegetalizzate) o con ZnSO4 (animalizzate) sono state disaggregate con la tecnica precedentemente descritta. Le cellule da blastule vegetalizzate si riaggregano in masse solide che non differenziano ne scheletro ne intestino. Quelle da blastule animalizzate danno origine a vescicole ciliate. Tentativi di combinazione di cellule da blastule animalizzate e vegetalizzate in un caso hanno dato origine ad aggregati con abbozzi di scheletro.
Distribution of protease activity in the blastula and early gastrula ofDiscoglossus pictus
1957
E stata determinata l'attivita proteasica nelle differenti regioni della blastula e della gastrula diDiscoglossus pictus. Nella blastula non esiste una differenza di attivita fra meta animale e vegetativa, quando si prenda come riferimento l'azoto citoplasmatico. Nella giovane gastrula il territorio presuntivo della corda e del sistema nervoso mostra una attivita piu elevata della epidermide presuntiva.
On the action of chromomycin on the eggs and embryos of Ciona intestinalis.
1964
E stata studiata l'azione della cromomicina sulle uova diCiona intestinalis (Ascidie) in diversi stadi di sviluppo. Essa non esercita alcun effetto sull'uovo vergine o appena fecondato; modifica invece notevolmente la morfogenesi se il trattamento e portato sulle uova in gastrulazione. I risultati vengono spiegati ammettendo che la cromomicina esercita la stessa azione che la actinomicina D e cioe inibisce la sintesi del MRNA.
Differential incorporation of labeled amino acids in the territories of the sea urchin blastula
1962
Blastule con mesenchima primario diParacentrotus lividus esposte a un trattamento di 30 min con S35-metionina, leucina-C14 e alanina-C14 mostrano nel territorio vegetativo una densita di tracce considerevolmente minore che in quello animale. Se gli embrioni sono invece esposti all'aminoacido radioattivo durante tutto lo sviluppo o durante le prime ore dopo la fecondazione, tale differenza tra territori animale e vegetativo non si osserva. Si discute il significato di questi reperti.