Activation of a new physiological state at the onset of vitellogenesis in Hyalophora follicles

Woodruff, Richard I.; Telfer, William H.

doi:10.1016/0012-1606(90)90207-y

Cited by 32 publications

(21 citation statements)

References 27 publications

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“…The membrane potential is not affected by incubation in 10 mM azide [12]. Internal Ca2+ activities proved also to be similar: there was no measurable difference between the two cells, and the levels were even higher than the 1.4-1.6 pM level seen in azide-inhibited vitellogenic follicles (Fig.…”

Section: Calcium In Prepolarized Previtellogenic Folliclesmentioning

confidence: 64%

“…With 10 mM azide, the steady-state membrane potentials diminish to smaller than -20 mV in each of the cell types (Fig. 2), and transcription, translation, vitellogenin uptake, and presumably all other ATP-dependent activities were suppressed [12] and unpublished observations). With 200 ~LM vanadate, the direction of the transbridge potential was reversed, but the steady-state membrane potentials were not as greatly affected as with azide (Fig.…”

Section: Inhibition With Azide and Vanadatementioning

confidence: 83%

“…With 200 ~LM vanadate, the direction of the transbridge potential was reversed, but the steady-state membrane potentials were not as greatly affected as with azide (Fig. 2), [12]. Since ammonium chloride at this concentration did not affect either membrane or transbridge potentials, the effect can be attributed to the metavanadate ion.…”

Section: Inhibition With Azide and Vanadatementioning

confidence: 84%

“…N. cecropia follicles remain in a relatively dormant state for -2 days after they are first formed [12] and then undergo a set of physiological changes associated with the initiation of vitellogenesis. The changes include a hyperpolarization that affects nurse cell membranes more strongly than the oocyte and hence sets up the transbridge electrical polarity.…”

Section: Discussionmentioning

confidence: 99%

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Steady‐state gradient in calcium ion activity across the intercellular bridges connecting oocytes and nurse cells in Hyalophora cecropia

Woodruff

Telfer

1994

Arch Insect Biochem Physiol

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Intracellular activities of K+, H+, Mg2+, Ca2+, and Cl-, measured with ion selective microelectrodes in the oocyte and the nurse cells in ovarian follicles of Hyalophora cecropia, indicated that a Ca2+ current is a key component of the electrical potential that is maintained across the intercellular bridges connecting these two cells. In vitellogenic follicles, Ca2+ activity averaged 650 nM in the oocyte and 190 nM in the nurse cells, whereas activities of the other ions studied differed between these cells by no more than 6%. Incubation in 200 microM ammonium vanadate caused a reversal of electrical potential from 8.3 mV, nurse cell negative, to 3.0 mV, oocyte negative, and at the same time the Ca2+ gradient was reversed: activities rose to an average 3.0 microM in the nurse cells and 1.6 microM in the oocyte, whereas transbridge ratios of the other cations remained at 0-3%. In immature follicles that had not yet initiated their transbridge potentials, Ca2+ activities averaged approximately 2 microM in both oocyte and nurse cells. The results suggest that vitellogenic follicles possess a vanadate-sensitive Ca2+ extrusion mechanism that is more powerful in the nurse cells than in the oocyte.

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Section: Calcium In Prepolarized Previtellogenic Folliclesmentioning

confidence: 64%

Section: Inhibition With Azide and Vanadatementioning

confidence: 83%

Section: Inhibition With Azide and Vanadatementioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Steady‐state gradient in calcium ion activity across the intercellular bridges connecting oocytes and nurse cells in Hyalophora cecropia

Woodruff

Telfer

1994

Arch Insect Biochem Physiol

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“…These changes are proposed to be responses to a single, branching cascade of activation, perhaps causally related to changes in the cell membrane permeability. In any case a more effective proton extrusion is an additional ability acquired by the follicles close to their time of activation (Woodruff and Telfer, 1990). Under physiological conditions, protons contribute to Em of the follicle .…”

Section: Introductionmentioning

confidence: 99%

Immunolocalization of a proton V‐ATPase in ovarian follicles of the tobacco hornworm Manduca sexta

Janssen¹,

Hendrickx²,

Klein³

et al. 1995

Arch Insect Biochem Physiol

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A monoclonal antibody, directed against an H ' translocating V-ATPase of the midgut of Manduca sexta, has been used for immunolocalization studies in ovarian follicles and testes of Manduca sexta. In testes, no distinct staining above background levels was observed. In vitellogenic follicles, V-ATPase irnmunoreactivity first appears in the cytoplasm of the trophocytes and then in the oocyte, but by far the strongest reaction is present in the region of the oolemma during endocytosis. All types of follicle cells surrounding both the oocyte and the trophocyte compartments show a distinct positive reaction. In the cylindrical follicle cells surrounding the oocyte, the irnrnunoreactivity is clearly restricted to the basal part. Our results suggest an important role for VATPase in vitellogenin uptake in Manduca, similar to that suggested on electrophysiological grounds in Hyalophora cecropia. o 1995 Wiley-Liss, Inc.

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Varied effects of 1-octanol on gap junctional communication between ovarian epithelial cells and oocytes ofOncopeltus fasciatus,Hyalophora cecropia, andDrosophila melanogaster

Adler

Woodruff

2000

Arch. Insect Biochem. Physiol.

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In insect gap junctions, species‐specific differences occur in response to the purported gap junction uncoupling agent, 1‐octanol. Changes in gap junctional communication between oocytes and their epithelial cells following treatment with 1‐octanol were assayed in Oncopeltus fasciatus (the milkweed bug), Hyalophora cecropia (the American silk moth), and Drosophila melanogaster. In all three species, microinjection of untreated control follicles with Lucifer yellow CH revealed extensive dye coupling among epithelial cells and between epithelial cells and their oocytes. Also for all three species, treatment with octanol appeared to completely block dye coupling and increase oocyte input resistance. The effect on electrical coupling varied. In Drosophila, octanol diminished the electrical coupling from 64% (0.64 coupling coefficient) in controls to 53% in treated follicles. In Hyalophora, the coupling ratio remained the same following treatment. In Oncopeltus, octanol actually increased the electrical coupling ratio from 84% in controls to 94% in treated follicles. While 0.5 mM octanol left some Oncopeltus epithelial cells dye coupled to the oocyte, the electrical coupling ratio was increased slightly more by this concentration than by 1 or 5 mM octanol solutions, although the differences were not significant. While input resistance (Ro ) increased in all three following treatment with octanol, there was considerable difference in the magnitude of the response. Average oocyte Ro for Oncopeltus increased the least of the three species, rising from 196–240 kOhm. Both Hyalophora, with a nearly fourfold increase from 230–900 kOhm or more, and Drosophila, with a twofold increase from 701 kOhm to over 1.2 MegOhm showed much larger changes. Results shown here indicate that insect gap junctions have more varied responses to this common gap junction antagonist than have been reported for their vertebrate counterparts. Arch. Insect Biochem. Physiol. 43:22–32, 2000. © 2000 Wiley‐Liss, Inc.

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Activation of a new physiological state at the onset of vitellogenesis in Hyalophora follicles

Cited by 32 publications

References 27 publications

Steady‐state gradient in calcium ion activity across the intercellular bridges connecting oocytes and nurse cells in Hyalophora cecropia

Steady‐state gradient in calcium ion activity across the intercellular bridges connecting oocytes and nurse cells in Hyalophora cecropia

Immunolocalization of a proton V‐ATPase in ovarian follicles of the tobacco hornworm Manduca sexta

Varied effects of 1-octanol on gap junctional communication between ovarian epithelial cells and oocytes ofOncopeltus fasciatus,Hyalophora cecropia, andDrosophila melanogaster

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