Plasma membrane calcium ATPase downregulation in dopaminergic neurons alters cellular physiology and motor behaviour in Drosophila melanogaster.

The accumulation of Ca2+ and its subsequent increase in oxidative stress is proposed to be involved in selective dysfunctionality of dopaminergic neurons, the main cell type affected in Parkinson's disease. To test the in vivo impact of Ca2+ increment in dopaminergic neurons physiology, we downregulated the plasma membrane Ca2+ ATPase (PMCA), a pump that extrudes cytosolic Ca2+ , by expressing PMCARNAi in Drosophila melanogaster dopaminergic neurons. In these animals, we observed major locomotor alterations paralleled to higher cytosolic Ca2+ and increased levels of oxidative stress in mitochondria. Interestingly, although no overt degeneration of dopaminergic neurons was observed, evidences of neuronal dysfunctionality were detected such as increases in presynaptic vesicles in dopaminergic neurons and in the levels of dopamine in the brain, as well as presence of toxic effects when PMCA was downregulated in the eye. Moreover, reduced PMCA levels were found in a Drosophila model of Parkinson's disease, Parkin knock-out, expanding the functional relevance of PMCA reduction to other Parkinson's disease-related models. In all, we have generated a new model to study motor abnormalities caused by increments in Ca2+ that lead to augmented oxidative stress in a dopaminergic environment, added to a rise in synaptic vesicles and dopamine levels.

Completion of metamorphosis after adult emergence in Ceratitis capitata (Diptera: Tephritidae).

The ecdysis of the imago is a crucial step in the development of holometabolous insects. However, no information on several aspects of Ceratitis capitata imago emergence and subsequent body maturation is available. We analysed behavioural events and evaluated the oxygen consumption and the dynamics of carbohydrate and lipid reserves during puparium extrication and in newly emerged imago until full wing expansion. A system for recording images with the corresponding software for image analysis was built for this purpose. After extrication, C. capitata showed two early postemergence phases: walking (6.56 ± 4.01 min, 6.2% of the wing spreading period, WSP) and the phase without locomotor motion (98.75 ± 26.04 min; 93.8% WSP). Three main events were recognized during the last phase. The first involved an initial expansion of the wings (11.12 ± 4.32 min). The second event was the progressive tanning of the body cuticle in general and the wing veins in particular, and the last entailed the definitive expansion of the wings to attain the characteristic arrow-shaped wing aspect. Our studies here complement previous descriptions of the tanning process of newly emerged medfly adults (Pérez et al., 2018). As a consequence of the results presented here, we consider that the initial events of the newly emerged adult could be interpreted as the last steps of metamorphosis.