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[3H]serotonin binds to two classes of sites in a crude membrane preparation of Drosophila melanogaster heads, with apparent Kd values of 1.4 and 130 nM, and a concentration of 0.2 and 1.5 pmol/mg protein, respectively. High salt concentration and a guanyl nucleotide decrease the number of the high-affinity binding sites. Low concentrations of ergot… (More)
[3H]Octopamine binds to a particulate preparation from heads of Drosophila melanogaster at a level of 0.5 +/- 0.1 pmol/mg protein, with an apparent dissociation constant of 6.0 +/- 0.9 x 10(-9) M at 26 degrees C. The binding is reduced or abolished by heat, trypsin, detergents, sulfhydryl reagents and EDTA. Low concentrations of MgCl2 or CaCl2 increase… (More)
Adenylate cyclase in washed, crude membrane fractions prepared from the Drosophila conditioning mutant, rutabaga, displays an altered responsiveness to Ca2+. The results are of interest since the modulation of adenylate cyclase activity by Ca2+ has recently been suggested to play a role in molecular events that underlie memory formation.
[3H]Dihydroergocryptine ([3H]DHE) binds to a particulate preparation from Drosophila melanogaster heads at a level of 2.4 +/- 0.4 pmol/mg protein, with an apparent dissociation constant of 2.0 +/- 0.5 nM. The binding sites are inactivated by heat, pronase treatment, and sulfhydryl and disulfide reagents. [3H]DHE binding is inhibited by low concentrations of… (More)
The activity of adenylate cyclase in homogenates prepared from the Drosophila memory mutant rutabaga is lower than normal. The effect is most pronounced in washed membranes prepared from the abdomen, in which the enzyme displays both a lower Vmax and a higher Km. Analysis of the effect of divalent cations suggests a lesion in the responsiveness of the… (More)
Adenylate cyclase in homogenates of Drosophila melanogaster is heterogeneous with respect to its affinity toward MgATP and its subcellular distribution. Km values for MgATP range, under similar assay conditions, from approximately 10(-5) M to approximately 10(-3) M, depending on the body region and on the subcellular localization of the enzyme. The majority… (More)
Air-fluorescence detectors such as the High Resolution Fly's Eye (HiRes) detector are very sensitive to upward-going, Earth-skimming ultrahigh energy electron-neutrino-induced showers. This is due to the relatively large interaction cross sections of these high-energy neutrinos and to the Landau-Pomeranchuk-Migdal (LPM) effect. The LPM effect causes a… (More)