Der Phosphatstoffwechsel des Facettenauges im Dunkeln und im Licht

Zusammenfassung 1. Bei Belichtung des Facettenauges vonCalliphora finden sich keine Veränderungen in den Mengen der phosphathaltigen Substanzgruppen, die zu den sogenannten Baustoffen gehören.2. Unter den zum energiebildenden Stoffwechsel gehörenden Metaboliten erfolgen bei Belichtung Veränderungen, die auf einen hohen Energiebedarf in den Augen hinweisen, insbesondere eine Verringerung des ATP und eine Zunahme des ADP und des freien anorganischen Phosphates.3. Die Belichtung verursacht eine Erhöhung der Umsatzraten aller phosphathaltigen Verbindungen; diese ist auffallend stark in der Gruppe der Phosphatide.4. Da dieser besonders erhöhte Umsatz der Phosphatide einen spezifischen Effekt darstellt, wird auf eine spezielle Bedeutung der Phosphatide für die Funktion der Lichtsinneszellen geschlossen.

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The phosphate metabolism of the compound eye in darkness and in light

The phosphate metabolism of the compound eye of the blow-fly (males of wild-type and mutantchalky [Langer 1962b] ofCalliphora erythrocephalaMeigen) was investigated in connection with its function as a sensory organ. Microchemical analyses were made to determine changes in the amounts of phosphorus compounds. After having kept flies in darkness or under illumination with ultraviolet light for six hours, the substances of the isolated eyes were separated according toSchneider (1945). In no fraction did the phosphate content vary between dark-adapted and illuminated eyes. On the other hand, the amount of free inorganic phosphate increased with illumination, whereas the phosphate liberated from acid-instable compounds during 7 minutes hydrolysis (N HCl; 100° C) decreased correspondingly. This effect was more pronounced in mutantchalky than in wild-type eyes. Specific enzymatic analyses of the adenine nucleotides showed — already after two hours — significantly less ATP in illuminated than in dark-adapted eyes of mutantchalky. In order to check the influence of adequate stimulation on the turnover of phosphate compounds, the extent of incorporation of radioactive phosphorus in the eyes was measured after feeding carrier free³²P-orthophosphate to starved flies (1 µC per fly). One to four hours after feeding, the over-all incorporation was found to be 35 % higher in light than in darkness (P<0.01). Within the fractions phosphatides showed an increase nearly three times that of the acid soluble compounds. This means that independently of the general rise in metabolic rate, there is a specific effect of illumination. Phosphatides are assumed to have special importance for the processes of excitation in the light sensitive cells of the compound eye.