Herman Steller

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Drosophila larvae are rapidly killed by food containing the antibiotic G418. The bacterial gene for neomycin resistance introduced in the genome by P-mediated transformation renders larvae resistant to G418 and able to grow to fertile adults. The neo gene transcribed from the herpes thymidine kinase promoter gives low levels of resistance but high levels(More)
Several observations suggest that developing ommatidia in the Drosophila eye have distinct dorsal-ventral (d-v) positional identities, despite their morphological uniformity. To identify molecular differences along the d-v axis of the eye, we carried out a systematic screen for P-element insertions that show nonuniform reporter gene expression along this(More)
Constructions containing the Drosophila white gene and different amounts and arrangements of its regulatory region were introduced into the germ line of white mutant flies by P-mediated transformation. The results obtained with the different transposon constructions show that different parts of the 1.8-kb region preceding the transcription start are(More)
We have transformed Drosophila melanogaster with modified P-element transposons, which express the transposase function from the heat-inducible hsp70 heat shock promoter. The Icarus transposon, which contains a direct hsp70-P fusion gene, behaved like a very active autonomous P element even before heat shock induction. Although heat shock led to abundant(More)
The K10 female sterility locus involved in establishment of the embryonic dorsoventral axis maps genetically to the 2E2-2F1 interval of the Drosophila X chromosome. We microdissected the 2E2-2F3 region from salivary gland chromosomes and used clones obtained from the microdissected fragments to establish a chromosomal walk covering more than 200 kb. To(More)
Using the microcloning approach a number of recombinant lambda phages carrying DNA from the 93D region have been isolated. Screening genomic libraries, cloned in phage lambda or cosmid vectors, with this isolated DNA yielded a series of overlapping DNA fragments from the region 93D6-7 as shown by in situ hybridization to polytene chromosomes. In vitro(More)
DNA of cloned genes injected into 15-30 min Drosophila embryos reaches nearly all the cells of the later embryo and its expression can be detected by Northern blot hybridisation. The injected DNA continues to be expressed at least up to the first instar larval stage and some developmental control of expression is retained. Genes normally expressed in the(More)
Plasmid DNA injected into early Drosophila embryos becomes enclosed in nuclei or nucleus-like structures where it remains at least throughout embryonic development. The fraction remaining in the cytoplasm is gradually degraded. The nuclear fraction is converted to a high-molecular-weight form consisting largely but not exclusively of tandem oligomers. Some(More)
We have used P-mediated transformation to introduce into the Drosophila genome transposons containing the hsp-70 heat shock promoter (hsp) placed at different distances upstream of the white gene. Using these constructions we found a strong terminator 250 nucleotides upstream of the white transcription start. When all white upstream sequences are deleted(More)
In the course of 1983 the contents of salmonellae was investigated as to quantity in the Kiel sewage water system by samples taken off-hand every fourteen days. Determining the numbers of salmonellae by mpn-method the canalisation of the west-side of Kiel fjord proved to be dominated by the abbatoir of Kiel-Wellsee. Additional evidence for that was given by(More)