Medical/biological study (experimental study)

Effects of an electric field on sleep quality and life span mediated by ultraviolet (UV)-A/blue light photoreceptor CRYPTOCHROME in Drosophila med./bio.

By: Kawasaki H, Okano H, Nedachi T, Nakagawa-Yagi Y, Hara A, Ishida N

Published in: Sci Rep 2021; 11: 20543

The aim of the study was to elucidate the molecular mechanisms underlying electric field effects in Drosophila melanogaster as a genetic animal model. The hypothesis should be tested that an electric field exposure of 50 Hz can improve sleep quality and extend the life span in wild type flies and that cryptochrome is essential for the electric field receptor system in Drosophila melanogaster.

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: 12, 24 or 48 h (dependent of the experiment); maybe longer (duration not exactly provided for each experiment)	electric field strength: 35 kV/m

Frequency	50 Hz
Type	electric field
Exposure duration	12, 24 or 48 h (dependent of the experiment); maybe longer (duration not exactly provided for each experiment)

Exposure source	electrode
Setup	flies and medium were placed in vials or tubes and placed 3–5 cm apart between the electrodes
Sham exposure	A sham exposure was conducted.

Measurand	Value	Type	Method	Mass	Remarks
electric field strength	35 kV/m	-	-	-	-

Exposed system:

invertebrate
Drosophila melanogaster/wild type (Oregon R), cryptochrome mutants (cry^b, cry⁰¹, cry⁰³, UAS-cry;cry⁰¹ and cry-Gal4;cry⁰¹), w¹¹¹⁸;P{GD738}v7239 and elav-Gal4
whole body

molecular biosynthesis: metabolome analysis following 48 h exposure (electrospray ionization-mass spectrometry (ESI–MS)) and ATP level following 24 h exposure (commercial kit)
life span under low nutrient and under starvation conditions (counting of dead flies every 2-3 days; exposure duration not exactly provided: continuously until death?)
sleep: sleep behavior following 12 h daytime or nighttime exposure (locomotor inactivity > 5 min)

Investigated system:

Time of investigation:

Exposure to 50 Hz electric fields during the daytime improved sleep quality in wild type flies, whereas nighttime exposure did not. This effect was not observed in cry^b mutant flies.
The average lifespan of exposed wild type flies of the low nutritional and the starvation condition was significantly increased by approx. 18 % and 20 %, respectively, compared with that of sham exposed flies. In contrast, electric field exposure did not alter the lifespan under starvation in any of the mutant flies.
Additionally, the data indicated that electric field exposure significantly increased ATP level and several nucleic acid metabolisms in the flies.
The data provide the first genetic evidence of a cryptochrome-based electric field sensitive system in animals.

Study character:

Migdał P et al. (2021): Changes in Honeybee Behavior Parameters under the Influence of the E-Field at 50 Hz and Variable Intensity
Migdał P et al. (2021): Effect of the electric field at 50 Hz and variable intensities on biochemical markers in the honey bee's hemolymph
Makarov VI et al. (2014): External control of the Drosophila melanogaster lifespan by combination of 3D oscillating low-frequency electric and magnetic fields
Pavelka J et al. (2001): Mechanism of the fluorescent light induced suppression of Curly phenotype in Drosophila melanogaster
Bindokas VP et al. (1989): Laboratory investigations of the electrical characteristics of honey bees and their exposure to intense electric fields
Watson DB (1988): The Bouncing of Drosophila Melanogaster in Power Frequency Electric Fields
Watson DB et al. (1983): Influence of Electric Fields on Flying Insects
Chernyshev VB et al. (1978): Effect of electric fields on the behavior of Drosophila melanogaster Meig