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Gut chitin synthase and sterols from larvae of Diaprepes abbreviatus (Coleoptera: Curculionidae)
Year:
1991
Authors :
Svoboda, James
;
.
Volume :
18
Co-Authors:
Ward, G.B., U.S. Horticultural Research Laboratory, Agriculture Research Service, U.S. Department of Agriculture, Orlando, Florida, United States, USDA, ARS, Plum Island Animal Disease Center, P.O. Box 848, Greenport, New York, 11944-0848, United States
Mayer, R.T., U.S. Horticultural Research Laboratory, Agriculture Research Service, U.S. Department of Agriculture, Orlando, Florida, United States
Feldlaufer, M.F., Insect Neurobiology and Hormone Laboratory, Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, Maryland, United States
Svoboda, J.A., Insect Neurobiology and Hormone Laboratory, Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, Maryland, United States
Facilitators :
From page:
105
To page:
117
(
Total pages:
13
)
Abstract:
Gut chitin synthase was characterized and the sterols and ecdysteroids in the sugarcane rootstalk borer weevil, Diaprepes abbreviatus, were identified. An in vitro cell‐free chitin synthase assay was developed using larval gut tissues from D. abbreviatus. Subcellular fractionation experiments showed that the majority of chitin synthase activity was located in 10,000g pellets. The gut chitin synthase requires Mg2+ to be fully active: 7–8‐fold increases in activity were obtained with 10 mM Mg2+ present in reaction mixture. Calcium also stimulated activity (4–5‐fold with 10 mM Ca2+), while Cu+2 completely inhibited at 1 mM. Other monovalent and divalent cations had little or no effect on activity. The pH and temperature optima were 7 and 25°C, respectively. Gut chitin synthesis was activated ca. 50% by trypsin treatments. GlcNAc stimulated chitin synthase activity, but Glc, GlcN and glycerin did not. Polyoxin D, UDP, and ADP inhibited the chitin synthase reaction with I50's of 75 μM, 2.3 mM, and 3.6 mM, respectively. Nikkomycin Z was a potent inhibitor of chitin synthase (91% inhibition at 10 μM). Tunicamycin and diflubenzuron had no effect on the enzyme. The apparent Km and Vmax for the gut chitin synthase were, respectively, 122.5 ± 7.4 μM and 426 ± 19.7 pmol/h/mg protein utilizing UDP‐GlcNAc as the substrate. Sterol analyses indicated that cholesterol was the major dietary and larval sterol. HPLC/RIA data indicated that 20‐hydroxyecdysone was the major molting hormone. Copyright © 1991 Wiley‐Liss, Inc.
Note:
Related Files :
chitin synthesis inhibitors
ecdysteroids
molting hormone
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Related Content
More details
DOI :
10.1002/arch.940180205
Article number:
Affiliations:
Database:
Scopus
Publication Type:
article
;
.
Language:
English
Editors' remarks:
ID:
30648
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:56
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Scientific Publication
Gut chitin synthase and sterols from larvae of Diaprepes abbreviatus (Coleoptera: Curculionidae)
18
Ward, G.B., U.S. Horticultural Research Laboratory, Agriculture Research Service, U.S. Department of Agriculture, Orlando, Florida, United States, USDA, ARS, Plum Island Animal Disease Center, P.O. Box 848, Greenport, New York, 11944-0848, United States
Mayer, R.T., U.S. Horticultural Research Laboratory, Agriculture Research Service, U.S. Department of Agriculture, Orlando, Florida, United States
Feldlaufer, M.F., Insect Neurobiology and Hormone Laboratory, Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, Maryland, United States
Svoboda, J.A., Insect Neurobiology and Hormone Laboratory, Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, Maryland, United States
Gut chitin synthase and sterols from larvae of Diaprepes abbreviatus (Coleoptera: Curculionidae)
Gut chitin synthase was characterized and the sterols and ecdysteroids in the sugarcane rootstalk borer weevil, Diaprepes abbreviatus, were identified. An in vitro cell‐free chitin synthase assay was developed using larval gut tissues from D. abbreviatus. Subcellular fractionation experiments showed that the majority of chitin synthase activity was located in 10,000g pellets. The gut chitin synthase requires Mg2+ to be fully active: 7–8‐fold increases in activity were obtained with 10 mM Mg2+ present in reaction mixture. Calcium also stimulated activity (4–5‐fold with 10 mM Ca2+), while Cu+2 completely inhibited at 1 mM. Other monovalent and divalent cations had little or no effect on activity. The pH and temperature optima were 7 and 25°C, respectively. Gut chitin synthesis was activated ca. 50% by trypsin treatments. GlcNAc stimulated chitin synthase activity, but Glc, GlcN and glycerin did not. Polyoxin D, UDP, and ADP inhibited the chitin synthase reaction with I50's of 75 μM, 2.3 mM, and 3.6 mM, respectively. Nikkomycin Z was a potent inhibitor of chitin synthase (91% inhibition at 10 μM). Tunicamycin and diflubenzuron had no effect on the enzyme. The apparent Km and Vmax for the gut chitin synthase were, respectively, 122.5 ± 7.4 μM and 426 ± 19.7 pmol/h/mg protein utilizing UDP‐GlcNAc as the substrate. Sterol analyses indicated that cholesterol was the major dietary and larval sterol. HPLC/RIA data indicated that 20‐hydroxyecdysone was the major molting hormone. Copyright © 1991 Wiley‐Liss, Inc.
Scientific Publication
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