The Aerobic and Anaerobic Utilization of Metabolic Energy During Insect Metamorphosis.

Abstract

Summary. The investigation is carried out on the fly Calliphora erythrocephala and concerns how the metabolic energy is utilized during the metamorphosis and which metabolic pathways are followed. The amount of protein, carbohydrate and fat were determined during the pupal life by the aid of biochemical analysis and by histochemical detection. The corresponding enzyme systems and the phosphorus metabolism were also studied. No nitrogen excretion occurs during the pupal life. The decomposition of proteins occurs only to a limited extent and goes probably only as far as to peptides. These peptides seem to be combined with phospholipids. The main fuel during the pupal development is fat supplemented by a small amount of carbohydrate. Very probably there is an interconversion of fat and carbohydrate. Anaerobically only carbohydrate is utilized. Principally the same glycolytic processes work aerobically as anaerobically. The anaerobic utilization of energy is very low compared with the aerobic. Anaerobiosis represents anabiosis. The U‐shaped metabolic curve can be explained by a corresponding decomposition of oxidative enzymes. Three physiologically‐conditioned periods during the pupal life can be distinguished: histolysis, histogenesis and differentiation. During the differentiation an incorporation occurs of soluble protein into the cell structure, a fixation of enzymes in the mitochondria. The adenosine triphosphatase activity is restored first during the differentiation period. Different pathways are utilized for energy gain. Thus, the glycolytic and the cyclophorase systems show an alternating variation during the metamorphosis indicating that growth and glycolysis are connected as well as differentiation and cyclophorase system. The glycolytic and the cyclophorase systems do not seem to be strictly cocatenated. The influence of anaerobiosis on respiratory enzymes was studied. During anaerobiosis an inactivation of the protein part of the enzymes occurs. By investigation of the restitution period histolysis was found to be an active process. The lethal influence of anaerobiosis on the developmental stage of the pupa is correlated to the respiratory activity with the exception of 70 per cent of the pupal age, where a temporarily increased lethal influence was found. This marks this state as a critical period in the development. The phosphorus metabolism was closely studied. The variation in amount of different phosphorus‐fractions during the development was established. The total phosphorus is constant during the metamorphosis period. Protein‐phosphorus, a part of the lipid‐phosphorus and the more easily hydrolyzable phosphorus have a U‐shaped variation. Low molecular phosphorus compounds are liberated during histolysis and later on incorporated. Des‐oxyribonucleic and ribonucleic acid vary inversely. An increase is desoxyribonucleic acid‐content is found in the histolysis center which do not correspond to an increase in Feulgen positive substance. The utilization of adenosine triphosphate decreases during histoly...

The Drosophila HNF4 nuclear receptor promotes glucose-stimulated insulin secretion and mitochondrial function in adults

“…Subsequent classical experiments in Lepidoptera , Bombyx , Rhodnius and Calliphora showed that this reduction in mitochondrial respiration during metamorphosis and dramatic rise in early adults is seen in multiple insect species, including Drosophila ( Bodine, 1925 ; Merkey et al, 2011 ). Consistent with this, the activity of oxidative enzyme systems and the levels of ATP also follow a “U-shaped curve” during development as the animal transitions from a non-feeding pupa to a motile and reproductively active adult fly ( Agrell, 1953 ). Although first described over 150 years ago, the regulation of this developmental increase in mitochondrial activity has remained undefined.…”

“…We agree with the reviewers that the discovery that dHNF4 may directly regulate mitochondrial gene expression and function is an exciting part of our paper. The evidence in support of this model includes ( 1 ) reduced expression of most of the 13 protein-coding mitochondrial genes in dHNF4 mutants. ( 2 ) Localization of dHNF4 protein to the predicted mtDNA promoter region by ChIP-seq, ( 3 ) no apparent change in mitochondrial DNA number (which we now show in Figure 3E ) and no effect on mitochondrial mt:Cyt-b transcription, which is predicted to be expressed from an independent mtDNA promoter, ( 4 ) localization of dHNF4 protein to both nuclei and mitochondria in antibody stains, and ( 5 ) indicators of mitochondrial dysfunction, including metabolomic data, reduced ATP levels, and mitochondrial fragmentation.…”

Parasitoid venom induces metabolic cascades in fly hosts

“…Glycolysis is the main pathway by which insects metabolize glucose to generate pyruvate for energy metabolism (Nation, 2008). During insect metamorphosis, regulation of glycolysis is thought to play a role in energy supply for development (Agrell, 1953). In our Control hosts, glycolytic intermediates increase from day 1 to 5, with 3-phosphoglycerate and glucose-6-phosphate increasing 3.13 fold ( p= 0.00018, MW U ) and 1.5 fold (p=0.00049, MW U ) respectively.…”

“…In our Control hosts, glycolytic intermediates increase from day 1 to 5, with 3-phosphoglycerate and glucose-6-phosphate increasing 3.13 fold ( p= 0.00018, MW U ) and 1.5 fold (p=0.00049, MW U ) respectively. These changes could represent an increase in glycolytic pathway activity that is related to growth (Agrell, 1953). In contrast, glucose shows no significant change over time ( One-way ANOVA, p< 0.05, q <0.10 ) and has the lowest temporal variance (%CV=7.57) of any measured metabolite (Figure S3a), possibly reflecting homeostatic regulation.…”

CHANGES IN THE CARBOHYDRATE CONTENT DURING THE METAMORPHOSIS OF DIFFERENT CASTES OF FORMICA POLYCTENA (HYMENOPTERA: FORMICIDAE)1

“…stored during the last larval instar (AGRELL, 1953, RUSSO-CAIA & CECERE, 1960. In Bombyx (DUTRIEU, 1961) trehalose appears first at the end of egg diapause; sugars are consumed by the time the cocoon is formed.…”