title: Reevaluation of electrophoresis in the Drosophila egg chamber.
abstract: To evaluate the hypothesis of electrophoretic transport of cytoplasmic components, the transfollicle potentials of Drosophila oocytes and nurse cells were measured using improved techniques. We found input resistances 20 to 1000 times higher than those in previous reports. Measurements were made in a large variety of conditions: in external potassium concentrations from 1 to 100 mM, over the concomitant membrane potential range -84 to -23 mV, from developmental stages 5 to 10, and with or without using hemolymph, anesthetics, or collagenase. In all of these circumstances, no voltage gradient was detectable with intracellular microelectrodes from nurse cells to oocyte or between nurse cells. No voltage gradient was detected with external suction electrodes. Our results do not support the electrophoretic theory.
authors.affiliation: Department of Biology, Yale University, New Haven, Connecticut 06511.
authors.forename: Y A
authors.initials: YA
authors.lastname: Sun
authors.forename: R J
authors.initials: RJ
authors.lastname: Wyman
mesh_terms: D000818:Animals; D001692:Biological Transport; D002413:Cations, Divalent / Q000494:pharmacology; D003593:Cytoplasm / Q000502:physiology; D004331:Drosophila melanogaster / Q000502:physiology*; D004594:Electrophysiology; D005260:Female; D006458:Hemolymph / Q000502:physiology; D009865:Oocytes / Q000502:physiology*; D009866:Oogenesis; D010053:Ovary / Q000166:cytology / Q000502:physiology*; D011188:Potassium / Q000494:pharmacology
chemical_list: D002413:Cations, Divalent; D011188:Potassium