Results 81 to 90 of about 357 (119)

Juvenile hormone-induced biosynthesis of vitellogenin in Leucophaea maderae

Archives of Biochemistry and Biophysics, 1976
Abstract Isolated abdomens of virgin female Leucophaea maderae, a South American cockroach, could be induced by a single injection of juvenile hormone I to synthesize vitellogenin. Synthetic capacity was assayed by removal of the fat body at various times after induction and incubation in organ culture with radioactive leucine for 5 h.
J, Koeppe, J, Ofengand
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Assay and identification of juvenile hormone binding proteins in leucophaea maderae

Molecular and Cellular Endocrinology, 1983
We modified a binding assay using polyethylene glycol (PEG) to precipitate bound hormone. Optimum precipitation occurred when reaction mixtures were incubated with 10-40% PEG and 1.25-2.5 mg/ml gamma-globulins for 2-90 min at 4 or 23 degrees C. Results from this assay and from the dextran-coated charcoal assay were similar.
G E, Kovalick, J K, Koeppe
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Follicle cell polyploidy in Leucophaea maderae: Regulation by juvenile hormone

Journal of Insect Physiology, 1985
Abstract Microspectrophotometric analysis of Feulgen-stained nuclei of the terminal follicle cells in the cockroach Leucophaea maderae showed that during maturation the follicle cells became polyploid. In virgin females, the follicle cell nuclei were diploid. After mating, and during vitellogenesis, the ploidy of the follicle cells increased from 2 C
Margot C. LaPointe, John K. Koeppe, K.K. Nair   +2 more
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Relationship of hemolymph juvenile hormone-binding protein to lipophorin in Leucophaea maderae

Insect Biochemistry, 1988
Abstract Monoclonal antibodies (MAb) specific for the hemolymph 220 kD juvenile hormone-binding protein (JHBP) of the cockroach, Leucophaea maderae, were used to further characterize the JHBP. Spleen cells, from mice immunized with semipurified hemolymph JHBP, were fused with myeloma cells to produce hybridomas secreting antibodies specific for the ...
Richard C. Rayne, John K. Koeppe
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Cytosolic and nuclear receptors for juvenile hormone in fat bodies of Leucophaea maderae

Insect Biochemistry, 1987
Abstract Cytosol preparations of fat bodies from adult Leucophaea maderae contained a population of very high affinity JH binding compounds (Kd of 10−9 M) which was only identifiable by the dextrancoated charcoal assay. These compounds exhibited a 1.5 times higher affinity to the natural enantiomer (10R-JH III) than to the racemate.
Franz Engelmann, Jaroslava Mala, Stephen S. Tobe   +2 more
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Esterolytic degradation of juvenile hormone in the haemolymph of the adult female of Leucophaea maderae

Insect Biochemistry, 1984
Two JH carboxylesterases were isolated from haemolymph of vitellogenic females by anion exchange chromatography. The high degree of purification achieved by this one step procedure is inferred by the absence of any protein stainable band (Coomassie blue or silver stain) on native polyacrylamide gels, yet enzyme activity was detectable in eluates of ...
Sonny Gunawan, Franz Engelmann
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Thymidine kinase from ovaries of the cockroach Leucophaea maderae: Regulation by juvenile hormone

Insect Biochemistry, 1984
Abstract Thymidine kinase (TK) (ATP: thymidine-5′-phosphotransferase, EC 2.7.1.75) was characterized in ovarian extracts from the cockroach Leucophaea maderae. TK activity was localized in the follicular epithelium surrounding the terminal oocyte, and subcellular fractionation studies indicated that TK was a cytosolic enzyme. Optimal assay conditions
Margot C. LaPointe, J.K. Koeppe
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Photoaffinity Labelling of Juvenile Hormone-Binding Proteins in Leucophaea maderae

1984
Juvenile hormone (JH) binding proteins have been identified in tissues from several insect species [1–3]. In the adult female cockroach Leucophaea maderae, JH-binding proteins have been found in the fat body [4], ovaries [5], and hemolymph [4,5]. Although some properties of these binding proteins have been described, further characterization has been ...
J. K. Koeppe, G. E. Kovalick, G. D. Prestwich   +2 more
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The juvenile hormone receptor of the cockroach Leucophaea maderae

Insect Biochemistry and Molecular Biology, 1995
The juvenile hormone (JH) receptor has been isolated and purified from fat bodies of females and males of Leucophaea maderae. The sequence of procedures that yielded an apparently pure compound involved ammonium sulfate precipitation (20-60% saturation cut), DEAE anion exchange column chromatography, and polyacrylamide gel electrophoresis.
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Juvenile hormone regulation of structural changes and DNA synthesis in the follicular epithelium of Leucophaea maderae

Journal of Insect Physiology, 1980
Abstract Juvenile hormone (JH I) stimulates specific morphological and biochemical changes in the follicular epithelium surrounding the terminal oocytes in Leucophaea maderae . These include extracellular and intracellular structural changes, increased rates of follicle cell DNA synthesis, and elevated follicle cell DNA concentrations.
John K. Koeppe, Ken Hobson, Susan E. Wellman   +2 more
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