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Biomedical subjects

G Schubiger

Publications and source records attributed to G Schubiger.

90 records · Page 5Linked to original sources
PubMed1977

Interaction of different egg parts in determination of various body regions in Drosophila melanogaster.

When Drosophila melanogaster embryos were ligated at very early stages of nuclear multiplication (45-60 min after egg deposition) for the entire period of embryogenesis, egg fragments of variable sizes were able to continue development up to the hatching stage. These ligated embryos differentiated larval structures; anterior fragments formed larval head and posterior fragments formed larval abdominal structures. Ligation always prevented the differentiation of some of the intermediate larval bands whereas the terminal ones were always formed. Identical results were obtained when embryos (45-60 min after egg deposition) were temporarily ligated for only 5 min. However, puncturing with a fine glass needle immediately after temporary ligation through the ligated area could give rise to complete differentiation of all the bands. Since puncturing disrupted the barrier produced by ligation, we propose that interaction between anterior and posterior egg regions is necessary to allow complete development.

Age Factors↗
PubMed1976

Projection of sensory neurons from a homeotic mutant appendage, Antennapedia, in Drosophila melanogaster.

Central projections of sensory neurons from homeotic mutant appendages (Antennapedia) of Drosophila melanogaster were compared with those of wild-type antennae and wild-type legs by means of degeneration and cobalt backfilling methods. Sensory axons originating from wild-type thoracic legs terminate within the ventral ipsilateral half of the corresponding neuropile segment and do not project to the brain. Sensory fibers from the third antennal segment (AIII) of wild-type animals project into the ipsilateral antennal glomerulus (AG) and to a lesser extent into the contralateral AG, whereas those from the second antennal segment terminate principally within the ipsilateral posterior antennal center. The sensory terminals of femur, tibia, and tarsi of the homeotic leg show a distribution very similar to that of the homologous wild-type antennal segment AIII, differing to a minor degree only in the size and precise localization of terminals within the antennal glomeruli. No degenerating axons were evident in ultrastructural examination of neck connectives after removal of homeotic legs. It is thus very improbable that any sensory fibers of the homeotic leg project to normal leg projection areas in the thoracico-abdominal ganglion. Several alternative explanations are offered for the apparent retention of antennal specificity by axons from the transformed appendage.

Animals↗
PubMed1976

[Longterm observation of latent diabetes mellitus in a prepubertal girl (author's transl)].

In a girl with latent diabetes mellitus, glucose tolerance and insulin release were regularly examined from 6 to 12 years of age. Under diet height and weight increased normally, the glucose intolerance disappeared, and the hypoinsulinism turned into hyperinsulinism with reactive hypoglycemia. This observation demonstrates that in a longitudinal study, the same patient may present in one period with glucose intolerance (latent diabetes) and insulin deficiency and in another period with normal glucose tolerance (prediabetes) and insulin excess.

Child↗
PubMed1975

Expression of homeotic mutations in duplicated and regenerated antennae of Drosophila melanogaster.

Three homeotic mutants, aristapedia (ssa and ssa-UCl) and Nasobemia (Ns) which involve antenna-leg transformations were analyzed with respect to their time of expression. In particular we studied the question of whether these mutations are expressed when the mutant cells pass through additional cell divisions in culture. Mutant antennal discs were cultured in vivo and allowed to duplicate the antennal anlage. Furthermore, regeneration of the mutant antennal anlage was obtained by culturing eye discs and a particular fragment of the eye disc. Both duplicated and regenerated antennae showed at least a partial transformation into leg structures which indicates that the mutant gene is expressed during proliferation in culture.

Animals↗
PubMedDate not supplied

Preferential binding of imaginal disk cells to embryonic segments of Drosophila.

Cell recognition and selective adhesion may be important in pattern formation; such processes in Drosophila melanogaster could be responsible for the maintenance of segment boundaries, the morphogenesis of metamorphosing imaginal disks, and the paths of axon outgrowth during neurogenesis. As cells from different imaginal disks of Drosophila are able to recognize and sort out from one another, we decided to investigate whether these larval cells could recognize and bind to the epidermis of intact embryos. We report here that imaginal disk cells bind preferentially to the epidermis of the embryonic segments from which they are derived: thoracic disk cells to thoracic segments and genital disk cells to abdominal segments. Furthermore, thoracic disk cells recognize and bind, without preference, to all segments of the homoeotic mutant Df(3R)P9 (ref. 6). We conclude, therefore, that cells of the same segmental origin have similar recognition properties at different developmental stages.

Animals↗