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  • 1
    Electronic Resource
    Electronic Resource
    Fate-mapping in wild-typeDrosophila melanogaster (1985)
    Springer
    Development genes and evolution 194 (1985), S. 213-216 
    Details
    ISSN: 1432-041X
    Keywords: Blastoderm fate map ; Embryogenesis ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Here we propose a fate map of theDrosophila blastoderm based on reconstructions of increasingly aged embryos and on results of horseradish peroxidase (HRP) injections in early gastrula cells. Boundaries of blastoderm anlagen have been extrapolated from size, form and location of the corresponding larval primordia, once these primordia become distinguishable at later embryonic stages.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848248
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  • 2
    Electronic Resource
    Electronic Resource
    The pattern of proliferation of the neuroblasts in the wild-type embryo of Drosophila melanogaster (1987)
    Springer
    Development genes and evolution 196 (1987), S. 473-485 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila melanogaster ; Proliferation ; Neuroblasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The pattern of neuroblast divisions was studied in thoracic and abdominal neuromeres of wild-type Drosophila melanogaster embryos stained with a monoclonal antibody directed against a chromatin-associated antigen. Since fixed material was used, our conclusions are based upon the statistical evaluation of a large number of accurately staged embryos, covering the stages between the formation of the cephalic furrow up to shortened germ band. Our observations point to a rather stereotypic pattern of proliferation, consisting of several parasynchronous cycles of division. The data suggest that all SI neuroblasts divide at least eight times, all SII neuroblasts six or seven times and all SIII neuroblasts at least five times. This conclusion is based on the mapping of mitotic neuroblasts and is supported by the progressive reduction of the neuroblast volume and by the results of cell countings performed on embryos of increasing age. No conclusive evidence was obtained concerning the fate of the neuroblasts after their last mitosis, i.e. it cannot be decided whether the neuroblasts degenerate or become incorporated as inconspicuous cells in the larval ventral cord. The duration of the cycles of division of the neuroblasts was found to be 40–50 min each, while in the case of ganglion mother cells about 100 min are required to complete one cell cycle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00399871
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  • 3
    Electronic Resource
    Electronic Resource
    Fate-mapping in wild-typeDrosophila melanogaster (1985)
    Springer
    Development genes and evolution 194 (1985), S. 181-195 
    Details
    ISSN: 1432-041X
    Keywords: Embryogenesis ; Pattern of cell divisions ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The pattern of cell proliferation and cell movements inDrosophila embryogenesis has been analysed with the aim of constructing a blastoderm fate map. Post-blastoderm cell proliferation starts at gastrulation and ends around the stage of germ band shortening. Three mitotic waves affect the embryonic cells according to a constant spatio-temporal pattern. For any of these waves mitotic activity starts at well-defined loci, which have been called mitotic centres. During the first and second mitotic waves all cells undergo mitosis, except for those of the amnioserosa, which do not proliferate at all. The third wave spares most of the ectodermal cells. Neuroblasts, progenitors of epidermal sensilla and germ line cells show their own, different pattern of proliferation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848246
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  • 4
    Electronic Resource
    Electronic Resource
    Proliferation pattern and early differentiation of the optic lobes in Drosophila melanogaster (1990)
    Springer
    Development genes and evolution 198 (1990), S. 264-274 
    Details
    ISSN: 1432-041X
    Keywords: Development ; Visual system ; Optic ganglia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The larval and early pupal development of the optic lobes in Drosophila is described qualitatively and quantitatively using [3H]thymidine autoradiography on 2-μm plastic sections. The optic lobes develop from 30–40 precursor cells present in each hemisphere of the freshly hatched larva. During the first and second larval instars, these cells develop to neuroblasts arranged in two epithelial optic anlagen. In the third larval instar and in the early pupa these neuroblasts generate the cells of the imaginal optic lobes at discrete proliferation zones, which can be correlated with individual visual neuropils. The different neuropils as well as the repetitive elements of each neuropil are generated in a defined temporal sequence. Cells of the medulla are the first to become postmitotic with the onset of the third larval instar, followed by cells of the lobula complex and finally of the lamina at about the middle of the third instar. The elements of each neuropil connected to the most posterior part of the retina are generated first, elements corresponding to the most anterior retina are generated last. The proliferation pattern of neuroblasts into ganglion mother cells and ganglion cells is likely to include equal as well as unequal divisions of neuroblasts, followed by one or two generations of ganglion mother cells. For the lamina the proliferation pattern and its temporal coordination with the differentiation of the retina are shown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00377393
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  • 5
    Electronic Resource
    Electronic Resource
    Defective ommatidial cell assembly leads to defective morphogenesis: a phenotypic analysis of the E(spl) D mutation of Drosophila melanogaster (1990)
    Springer
    Development genes and evolution 198 (1990), S. 286-294 
    Details
    ISSN: 1432-041X
    Keywords: Compound eye morphogenesis ; Enhancer of split ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The spl mutation of the N gene causes, among other phenotypic traits, the lack of a few ommatidia, roughness and a general reduction in the size of the compound eye; these defects are drastically enhanced by the dominant mutation E(spl) D. We have studied cellular and developmental aspects of the phenotypic interaction between spl and E(spl) D. We found that the initial clustering of photoreceptor cells is affected in eye imaginal discs of spl larvae causing the defects visible in the adult eye. The degree of disorganization of the spl/Y; E(spl) D/ + eye disc is much higher, only a few photoreceptor cells are able to group with representatives of the other cell types and differentiate normally. BrdU incorporation shows that the proliferation pattern of the spl/Y; E(spl) D/ + disc cells during the third instar is normal. Abundant cell death occurs posteriorly in the mutant discs, which accounts for their small size. Finally, we found that in the eye imaginal disc the transcription of m8, the E(spl) gene, responsible for the enhancement of the spl phenotype caused by the E(spl) D mutation, is restricted to the morphogenetic furrow, where the ommatidial cells start grouping with each other to take on their future developmental fates; the m8 transcription rate is highly increased in E(spl) D eye discs. All these observations indicate that the assembly of the ommatidial cells is affected in the spl/Y; E(spl) D/ + disc and that the other abnormalities are morphogenetic consequences of the defective cell grouping.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00377395
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  • 6
    Electronic Resource
    Electronic Resource
    Lineage analysis of transplanted individual cells in embryos of Drosophila melanogaster (1986)
    Springer
    Development genes and evolution 195 (1986), S. 489-498 
    Details
    ISSN: 1432-041X
    Keywords: Pole cells and midgut progenitors ; Cell lineages ; Embryogenesis ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In this paper experiments concerning some aspects of the development of pole cells and midgut progenitors in Drosophila are reported. Cells were labelled by injecting horseradish-peroxidase (HRP) in embryos before pole bud formation and transplanted at different stages into unlabelled embryos, where the transplanted cells developed together with the unlabelled cells of the host. The hosts were then fixed and stained at different ages in order to demonstrate the presence of HRP in the progenies of transplanted cells. The main conlusions of the study are as follows. The gonads are the only organ to the formation of which pole cells normally contribute; those pole cells which do not participate in the formation of the gonads are finally eliminated or degenerate. Since the number of primordial germ cells in the gonads is the same irrespective of the number of pole cells present in the embryo, an (unknown) mechanism must exist regulating the final number of pole cells in each of the gonads. After their formation and before reaching the gonads, pole cells have been found to divide only up to two times. With respect to the midgut progenitors, the cells of both anlagen have been found to be committed to develop into midgut, although they behave as equivalent in that they do not apparently distinguish between the anterior and posterior anlage. Midgut progenitors have been found to divide a maximum of three times and to produce two different types of cells, epithelial cells of the midgut wall and spindle-like cells located internally in the gut.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00375889
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  • 7
    Electronic Resource
    Electronic Resource
    Neurulation in the anterior trunk region of the zebrafish Brachydanio rerio (1993)
    Springer
    Development genes and evolution 202 (1993), S. 250-259 
    Details
    ISSN: 1432-041X
    Keywords: Zebrafish ; Neurulation ; Dye applications ; Neural anlage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have studied the process of neurulation within the anterior trunk region of the zebrafish by means of serial sectioning of staged embryos and labelling cells by applications of the dye Dil and intracellular injections of fluoresceine dextran amine. The first morphological manifestation of the prospective neural plate is a dorsomedial ectodermal thickening which becomes visible immediately after gastrulation. Within 1–2 h, by the time somatogenesis begins, two bilaterally symmetrical thickenings have appeared more laterally, which eventually fuse with the medial thickening to form the neural keel. The central canal forms next by separation of the cells on either side of the midline of the neural keel, beginning ventrally at the 17-somite stage and progressing towards dorsal levels. By means of fluorescent dye labelling in the late gastrula, we found that both the medial and lateral thickenings contribute to the nerve cord. The medial thickening was found to contain, exclusively, neural progenitor cells from the 90–100% epiboly stage on, whereas the adjacent regions contained a mixture of neural and epidermal progenitor cells, as well as prospective neural crest cells. Between the 90–100% epiboly and 2-somite stages, this heterogeneity of developmental capabilities is resolved into territories, with epidermogenic and neurogenic cells clearly separated from each other. To achieve this segregation into neural and epidermal anlagen, cells from the lateral thickenings have to move over a distance of roughly 400 μm within 1–2 h. Epidermal overgrowth of the nerve cord occurs during the morphogenetic movements that accompany nerve cord formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00363214
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  • 8
    Electronic Resource
    Electronic Resource
    A new β-globin gene from the zebrafish, β E1 , and its pattern of transcription during embryogenesis (1999)
    Springer
    Development genes and evolution 209 (1999), S. 126-131 
    Details
    ISSN: 1432-041X
    Keywords: Key words Globin genes ; Transcription pattern ; Erythropoiesis ; Zebrafish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  In a search for novel, developmentally regulated genes we screened randomly picked cDNA clones, obtained from zebrafish mRNA, by in situ hybridization with digoxigenin-labelled riboprobes. Out of 150 clones tested, 1 codes for a new β-globin gene and is expressed during embryogenesis. Here we describe its pattern of expression and its use as a marker for early zebrafish erythropoiesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050235
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  • 9
    Electronic Resource
    Electronic Resource
    Region-specific cell clones in the developing spinal cord of the zebrafish (1999)
    Springer
    Development genes and evolution 209 (1999), S. 135-144 
    Details
    ISSN: 1432-041X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  To analyse the proliferative abilities of cells within particular regions of the zebrafish neural plate, injections of fluorescein-dextran were made into single cells at either medial or intermediary positions in the neural plate region of two-somite stage embryos. The resulting cell clones were analysed in 3.5-day-old embryos. Clones with similar compositions were found among those derived from injections in both regions, and these were grouped into classes. 78 clones 29 obtained following injections in the medial region, and 22 of 59 cell clones derived from injections in the intermediary region, were classifiable into 9 and 10 different classes, respectively, each comprising a variable number of clones. Several identified cell types, as well as each of the clone classes themselves, were specific for the regions of the neural plate from which they derived, i.e. they were not represented among the clones derived from the other region. These results suggest that the composition of the lineages derived from particular cells is constant in different animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050237
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  • 10
    Electronic Resource
    Electronic Resource
    Transcription of a zebrafish gene of the hairy-Enhancer of split family delineates the midbrain anlage in the neural plate (1996)
    Springer
    Development genes and evolution 206 (1996), S. 153-160 
    Details
    ISSN: 1432-041X
    Keywords: Key words hairy-E(spl) homologues ; Zebrafish ; Midbrain primordium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  her5 encodes a basic helix-loop-helix (bHLH) protein with all features characteristic of the Drosophila hairy-E(spl) family. her5 is expressed in a band of cells within the neural anlage from about 90% epiboly on to at least 36 h postfertilization (hpf). After completion of brain morphogenesis, her5-expressing cells are located in the caudal region of the midbrain, at the boundary with the rhombencephalon. Labelling of cells within the her5 expression domain in the neural plate by injection of fluorescein-dextran allows their labelled progeny to be localized in the 36-hpf-old embryo using an anti-fluorescein antibody. This shows that the her5 expression domain corresponds to the midbrain primordium, including both the tectum and the tegmentum, in the neural plate. A possible function for her5 in regionalization of the brain and/or control of the midbrain-hindbrain boundary is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050041
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