Midgut and fatbody mitochondrial transhydrogenase activities during larval-pupal development of the tobacco hornworm, Manduca sexta
| Autor: | Kurt P. Vandock, Stan L. Smith, Christopher A. Drummond, Carmen F. Fioravanti |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Physiology
ATPase Fat Body 20-Hydroxyecdysone Biology Mitochondrion chemistry.chemical_compound Manduca NADP Transhydrogenases Animals fungi Pupa Midgut NAD biology.organism_classification Enzyme assay Biochemistry chemistry Manduca sexta Larva Insect Science biology.protein Insect Proteins NAD+ kinase Digestive System NADP Ecdysone |
| Zdroj: | Journal of Insect Physiology. 56:774-779 |
| ISSN: | 0022-1910 |
| DOI: | 10.1016/j.jinsphys.2010.01.008 |
| Popis: | Midgut and fatbody mitochondria from fifth larval instar Manduca sexta display a membrane-associated transhydrogenase that catalyzes a reversible hydride ion transfer between NADP(H) and NAD(H). The NADPH-forming activity occurs as a nonenergy- or energy-linked activity with energy for the latter derived from either electron transport-dependent NADH or succinate utilization, or ATP hydrolysis by Mg++-dependent ATPase. During the ten-day developmental period preceding the larval-pupal molt (fifth larval instar), significant peaks in the mitochondrial transhydrogenase activities of midgut and fatbody tissues were noted and these peaks were coincident with the onset of wandering behavior and with the fifty-fold increase in ecdysone 20-monooxygenase (E20-M) activity previously reported for M. sexta midgut. Since E20-M preferentially uses NADPH in catalyzing ecdysone conversion to the physiologically active molting hormone, 20-hydroxyecdysone, the physiological and developmental significance of the mitochondrial, NADPH-forming energy-linked transhydrogenations were made apparent. Moreover, that the increases in all transhydrogenase activities resulted from de novo enzyme synthesis were indicated by the cycloheximide-dependent reductions in these activities. |
| Databáze: | OpenAIRE |
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