Search results for "structures"
showing 10 items of 4815 documents
Immunological detection of phenylalanine hydroxylase protein in Drosophila melanogaster.
1992
A monoclonal antibody raised against monkey liver phenylalanine hydroxylase (PAH) has been used to detect this protein in Drosophila melanogaster. A cross-reacting material (CRM) band of apparent molecular mass 50-52 kDa, equivalent to that deduced for the Drosophila melanogaster PAH protein based on the pah gene cDNA sequence, has been detected. This CRM was analysed throughout development and showed an equivalent pattern to that reported for PAH activity in this insect, with maxima at pupariation and at pharate adult formation. Distribution of this CRM in larval tissues, the haemolymph and the adult body is mainly restricted to the larval fat body and the adult head. Demonstration of this…
Hyperplastic Conotruncal Endocardial Cushions and Transposition of Great Arteries in Perlecan-Null Mice
2002
Perlecan is a heparan-sulfate proteoglycan abundantly expressed in pericellular matrices and basement membranes during development. Inactivation of the perlecan gene in mice is lethal at two developmental stages: around E10 and around birth. We report a high incidence of malformations of the cardiac outflow tract in perlecan-deficient embryos. Complete transposition of great arteries was diagnosed in 11 out of 15 late embryos studied (73%). Three of these 11 embryos also showed malformations of semilunar valves. Mesenchymal cells in the outflow tract were abnormally abundant in mutant embryos by E9.5, when the endocardial-mesenchymal transformation starts in wild-type embryos. At E10.5, mut…
In vitro rescue of zygotic embryos of sour orange, Citrus aurantium L., and their detection based on RFLP analysis
1998
Embryo development in vivo has been studied in four Citrus aurantium L. polyembryonic genotypes. Seeds were collected 65, 85, 105, 125 and 220 days after pollination (DAP). None of the immature seeds harvested 65 and 85 DAP contained visible embryos. A single embryo at a more advanced developmental stage was observed in the central position at the micropylar apex of the embryo sac in about 74% of seeds harvested at 105 DAP, while at 125 and 220 DAP the majority of seeds had two or more embryos at the same developmental stage crowded together. Restriction fragment length polymorphism (RFLP) analysis of low- and high-copy-number nuclear DNA was used to distinguish zygotic from nucellar seedli…
In vitro differentiation of E-N-CAM expressing rat neural precursor cells isolated by FACS during prenatal development
1994
Most fetal rat brain cells expressing the embryonal, highly sialylated form of the cell adhesion molecule N-CAM (E-N-CAM) are precursor cells, as judged from the absence of marker molecules specific for mature neural cell types. However, the detection of E-N-CAM+ cells in frozen sections does not provide information on the lineage-specific differentiation of these cells during development. To investigate their differentiation behaviour in vitro, E-N-CAM+ cells were isolated at different times of brain development by fluorescence-activated cell sorting (FACS), using a monoclonal antibody (Mab RB21-7) which specifically recognizes polysialic acid (PSA) residues on E-N-CAM. Double-immunofluore…
Patterns of Puffing Activity in the Polytene Chromosomes of Drosophila Subobscura
1982
The puffs and Balbiani rings are the visible expression of sites of genetic activity (Beerman, 1952). Since Beermann’s original hypothesis, puffing patterns for several species of Diptera have been described. Thus for the genus Drosophila, Ashburner (1967, 1969a and 1969b) has reported the puffing pattern of Drosophila melanogaster and Drosophila simulans, Beredens (1965) of Drosophila hydei, and Moriwaki and Ito (1969) of Drosophila ananassae. In a previous paper Frutos and Latorre (1981) have determined puffing patterns of the J and U chromosomes of Drosophila subobscura. This species shows a rich chromosomal polymorphism and the puffing pattern of several chromosomal rearrangements of th…
Sonic hedgehog promotes the migration and proliferation of optic nerve oligodendrocyte precursors.
2007
Optic nerve (ON) oligodendrocyte precursors (OPCs) are generated under the influence of the Sonic hedgehog (Shh) in the preoptic area from where they migrate to colonise the entire nerve. The molecular events that control this migration are still poorly understood. Recent studies suggested that Shh is often used by the same cell population to control different processes, including cell proliferation and migration, raising the possibility that Shh could contribute to these aspects of OPC development. In support of this idea, we show here that Shh induces the proliferation of OPCs derived from embryonic mouse ON explants and acts as a chemoattractant for their migration. In ovo injections of …
ISOLATION OF CYTOCHROME OXIDASE COMPLEX FROM SEA URCHIN MITOCHONDRIAL INNER MEMBRANES
1996
Cytochrome oxidase complex has been isolated and purified from sea urchin mitochondrial inner membranes. The complex exhibited a discrete number of bands in PAGE and a 17 kDa band was recognized by an anti-human subunit IV antibody. No bands were recognized by an anti-yeast hsp60 antibody and an anti-sea urchin β ATPase subunit.
Developmental profiles of epidermal mRNAs during the pupal-adult molt of Tenebrio molitor and isolation of a cDNA clone encoding an adult cuticular p…
1992
0012-1606 (Print) Journal Article; Changes in translatable mRNAs from the wing epidermis of the Coleoptera Tenebrio molitor have been investigated during metamorphosis by analysis of in vitro translated products. Striking differences between the patterns obtained from mRNAs extracted during pupal and adult cuticle secretion indicated that a drastic change in gene expression occurs during the pupal-adult transition. In addition to these stage-specific modifications, the mRNA patterns changed within each cuticular synthesis program (pupal or adult), especially at ecdysis. After tritiated leucine incorporation, some of the major radiolabeled cuticular proteins showed similar changes suggesting…
Plexin-B1 activates NF-κB and IL-8 to promote a pro-angiogenic response in endothelial cells.
2011
Background The semaphorins and their receptors, the plexins, are proteins related to c-Met and the scatter factors that have been implicated in an expanding signal transduction network involving co-receptors, RhoA and Ras activation and deactivation, and phosphorylation events. Our previous work has demonstrated that Semaphorin 4D (Sema4D) acts through its receptor, Plexin-B1, on endothelial cells to promote angiogenesis in a RhoA and Akt-dependent manner. Since NF-κB has been linked to promotion of angiogenesis and can be activated by Akt in some contexts, we wanted to examine NF-κB in Sema4D treated cells to determine if there was biological significance for the pro-angiogenic phenotype o…
Activation of TRK Genes in Ewingʼs Sarcoma Trk A Receptor Expression Linked to Neural Differentiation
1997
Trk receptors have been identified by immunohistochemical methods in primitive neuroectodermal tumor (PNET)/Ewing's sarcoma (ES). However, the presence of different members of the Trk family of receptors in PNET/ES has not been specified. We have examined whether Trk A, B, and C receptors are specifically expressed in ES both with and without features of neural differentiation. Ten ES tumors (five primary tumors of bone and five extraosseous tumors transplanted into nude mice) were investigated for expression of Trk receptors by immunohistochemistry and reverse transcription-polymerase chain reaction. One primary ES and the five grafted ES tumors exhibited signs of neural differentiation; t…