Original paper

The Circadian Rhythm of Tyrosine Aminotransferase Activity in the Fat Body of Drosophila melanogaster in Different Stages of Ontogeny (Diptera: Drosophilidae)

Hardeland, Rüdiger

Entomologia Generalis Volume 20 Number 3 (1996), p. 177 - 183

18 references

published: Jan 1, 1996

DOI: 10.1127/entom.gen/20/1996/177

BibTeX file

ArtNo. ESP146002003005, Price: 9.90 €

Download preview PDF Buy as PDF

Abstract

Fat body of 3rd instar migrating larvae [mL,], praepupae [Prp], and imagines [Img] of Drosophila melanogaster Meigen 1804 was isolated by treating the dissected insects with collagenase and hyaluronidase, centrifuging, and collecting the floating material consisting of dissociated fat cells and fat cell aggregates. In mL, and Prp, 2 isoforms of fat cell tyrosine aminotransferase (TAT) can be distinguished which differ with regard to the pH optimum (pH 5.6 and pH 6.0), whereas the pH 5.6 isoenzyme has disappeared in Img. Both, in a light / dark cycle of 12:12 hours, and in constant darkness, circadian oscillations of TAT activity were demonstrated. In mL, and Prp, the pH 5.6 isoenzyme shows a bimodal activity pattern, with maxima at the end of (subjective) day and middle of (subjective) night, whereas the pH 6.0 isoenzyme exhibits a unimodal low-amplitude rhythm having a maximum at the end of (subjective) night. In Img, the pH 6.0 isoenzyme oscillates with a high amplitude and prominent peaks at the end of both (subjective) day and night.

Kurzfassung

Fettkörper (a) von in der Wanderphase befindlichen Angehörigen des 3. Larvenstadiums [mL] (b) von Vorpuppen [Prp] und (c) von Imagines [Img] der Essigfliegen-Art Drosophila melanogaster Meigen 1804 wurden durch Behandlung sezierter Tiere mit Collagenase und Hyaluronidase, Zentrifugation und Sammeln des aus dissoziierten Fettzellen und Fettzell-Aggregaten bestehenden flottierenden Materials isoliert. mL, ebenso wie Prp besitzen zwei Isoformen der Tyrosin-Aminotransferase (TAT) des Fettkörpers, die sich hinsichtlich des pH-Optimums unterscheiden (pH 5,6 und pH 6,0); bei den Img dagegen ist das pH-5, 6-Isoenzym verschwunden. Sowohl in einem Hell-Dunkel-Zyklus von 12:12 Stunden als auch in konstanter Dunkelheit wurden zirkadiane Oszillationen der TAT-Aktivität nachgewiesen.

Keywords

circadian rhythmsdevelopmentDrosophila melanogasterfat bodytyrosine aminotransferase