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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 193 (1984), S. 388-393 
    ISSN: 1432-041X
    Keywords: Drosophila ; Oogenesis ; Ring canals ; Oocyte determination ; Polarity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The pattern of intercellular connections between germ line cells has been studied in follicles of the mutantdicephalic (dic), which possess nurse cell clusters at both poles. Staining of follicles with a fluorescent rhodamine conjugate of phalloidin reveals ring canals and cell membranes and thus allows us to reconstruct the spatial organization of the follicle. Each germ line cell can be identified by the pattern of cell-cell connections which reflect the mitotic history of individual cells in the 16-cell cluster. The results indicate that in both wild-type anddicephalic cystocyte clusters one of the two cells with four ring canals normally becomes the pro-oocyte. However, in some follicles (dicephalic and wild-type) oocytes were found with fewer or more than four ring canals. Indic follicles, one or several nurse cells may become disconnected from the other cells during oocyte growth at stage 9–10. Such disconnected cells cannot later on empty their cytoplasm into the oocyte. This, in turn, might be of consequence for the determination of axial polarity of the embryo.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-041X
    Keywords: Apis mellifera ; Homeobox genes ; Dfd ; In situ hybridization ; Blastoderm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have isolated and characterized a homeoboxcontaining gene from the honeybee Apis mellifera. Its homeobox region shows a high degree of sequence similarity to the homeobox of the Drosophila gene Deformed (Dfd). At the DNA level 82% of the basepairs are the same, whereas the putative amino acid sequences are identical between the bee and the fruitfly genes. Similarity is also present 5′ and 3′ to the homeobox. Using this isolate as a probe we have performed in situ hybridization on sections from blastoderm-stage embryos of the honeybee Apis mellifera. In early blastoderm stages we found a rather irregular pattern of labelled nuclei. In middle stages we found silver grains over each nucleus and also over the cytoplasm in a belt of blastoderm cells in the prospective gnathal region. These results indicate that the Deformed genes from honeybee and fruitfly are homologous both with respect to their DNA sequence and their spatial and temporal pattern of expression during embryogenesis.
    Type of Medium: Electronic Resource
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