A complementary transposon tool kit for Drosophila melanogaster using P and piggyBac

With the availability of complete genome sequence for Drosophila melanogaster, one of the next strategic goals for fly researchers is a complete gene knockout collection. The P-element transposon, the workhorse of D. melanogaster molecular genetics, has a pronounced nonrandom insertion spectrum. It has been estimated that 87% saturation of the approximately 13,500-gene complement of D. melanogaster might require generating and analyzing up to 150,000 insertions. We describe specific improvements to the lepidopteran transposon piggyBac and the P element that enabled us to tag and disrupt genes in D. melanogaster more efficiently. We generated over 29,000 inserts resulting in 53% gene saturation and a more diverse collection of phenotypically stronger insertional alleles. We found that piggyBac has distinct global and local gene-tagging behavior from that of P elements. Notably, piggyBac excisions from the germ line are nearly always precise, piggyBac does not share chromosomal hotspots associated with P and piggyBac is more effective at gene disruption because it lacks the P bias for insertion in 5' regulatory sequences.     

Vesicles carrying nuclear material in matureCyprinus carpio erythrocytes

Zusammenfassung Chromatinhaltige feulgenpositive Bläschen wurden im Cytoplasma der Erythrocyten vonCyprinus carpio gefunden. Sie haben ihren Ursprung in den unmittelbar an der Kernmembran anliegenden Mitochondrien, die während der Chromatinaufnahme allmählich ihre Struktur verlieren.

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The authors wish to thank Mrs.Vera Mondin Weisz and Mr.C. A. Gonçalves Silva for their technical assistance and Mrs.Sibylle Heller for her editorial aid and translation. This research has been supported by the Conselho Nacional de Pesquisas (Proc. No. 10112/71) and Fundo Especial de Despesas do Instituto Butantan.     

Deoxyribonuclease immobilized on the erythrocytes

Summary Bovine pancreatic deoxyribonuclease (DNase I) was immobilized on human erythrocytes with several procedures. DNase immobilized on the erythrocytes by chromic chloride showed DNase activity in vitro. Other binding procedures inhibit the immobilized DNase activity.     

Isolation of (−)-cryptosporiopsin,a chlorinated cyclopentenone fungitoxic metabolite fromPhialophora asteris f. sp.helianthi

Summary The (–)-enantiomer of cryptosporiopsin, a chlorinated cyclopentenone fungitoxic metabolite, was isolated fromPhialophora asteris f. sp.helianthi. Next to a comparable fungitoxic activity as shown by crypstosporiopsin, the product particularly inhibits growth ofSclerotinia sclerotiorum, an important pathogen on sunflower. Two further metabolites were tentatively identified as a stereoisomer of cryptosporiopsin and its dehydrated derivative.The authors are much indebted to Dr.G. M. Strunz (Canadian Forestry Service) for valuable suggestions and the generous gift of cryptosporiopsin and to the University of Utrecht for the part-time fellowship to one of us (Y.T.) given.     

Uptake of3H-GABA (γ-aminobutyric acid) and3H-leucine in the pancreatic islets and substantia nigra of the rat

Summary Isolated pancreatic islets and thin slices of substantia nigra (SN) of the rat were incubated in a medium containing³H-GABA or³H-leucine to test the activity of both tissues in the uptake of those substances. Pancreatic islets showed a low uptake of both³H-GABA and³H-leucine, but SN had a high activity in the uptake of³H-GABA, though not for³H-leucine. This suggests that GABA contained at high levels in the pancreatic islets plays some functional role other than in neurotransmission as in the central nervous system (CNS).