この研究は、雄のキイロショウジョウバエに対する超低周波磁界（ELF-MF）の短期および長期ばく露の影響をトランスクリプトミック分析およびQRT-PCRを用いて調べた。ELF-MFばく露にはヘルムホルツコイルを用い、ばく露レベルは3.03 ± 0.04 mTであった。ばく露期間は、卵から、さなぎ、羽化、成虫（3日齢）間での全期間（1世代；312時間）を長期ばく露、羽化から成虫（3日齢）までの72時間を短期ばく露とした。その結果、短期ばく露では439個の遺伝子が上方調節、874個の遺伝子が下方調節された；長期ばく露では、514個の遺伝子が上方調節、1206個の遺伝子が下方調節された、と報告し、その変化の内容を詳しく述べている。
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To investigate the in vivo effects of short-term and long-term exposure to extremely low frequency magnetic fields on the male fruit fly (Drosophila melanogaster).
Two experiments were performed: In the first experiment, a transcriptome analysis was performed. Three groups were examined (n=20 per group): 1 a) control group, 1 b) short-term exposure (72 hours in the adult form) and 1 c) long-term exposure (312 hours as egg, larvae and in the adult form). As a further verification quantitative real-time RT-PCR was used. The same groups as for the transcriptome analysis were formed, but with 60 individuals per group. RNA for gene expression analysis was extracted from three day-old flies in all groups.
In the second experiment, fertility was analyzed. Four groups were analyzed (n=20 for every examined group or exposure duration, respectively): 2 a) short-term control group, 2 b) short-term exposure (8, 16, 24, 48, 72 hours in the adult form), 2 c) long-term control group and 2 d) long-term exposure (312 hours as egg, larvae and in the adult form). Directly after the exposure, male flies were mated with unexposed virgin females. The number of F1 pupae was used to represent the fertility of the male flies.
|ばく露時間||continuous for up to 72 hours|
|Additional information||short-term exposure|
|ばく露装置の詳細||Helmholtz coil (length 15 cm, diameter 40 cm) was wrapped with 260 turns of a single strand of copper wire; fruit flies were placed in a 19 cm space between the two coils; system was put in an incubator (25 ± 0.5°C, 60% relative humidity, 12 hours dark/light cycle); incubator, including the exposure system was put in room at 25°C|
|Additional information||control group was placed in another incubator in a location with an equal background magnetic field|
|ばく露時間||continuous for 312 hours|
|Additional information||long-term exposure|
The transcriptome analysis showed that under short-term exposure conditions 439 genes were up-regulated and 874 genes were down-regulated in comparison to the control group, while under long-term conditions 514 genes were up-regulated and 1206 were down-regulated. Taken together both exposure groups (short-term and longt-term exposure), the expression of 836 genes was modified. Out of those, 6 genes related to apoptosis, aging, immunological stress and reproduction were verified via PCR: The genes Jra, ark, decay and cat were down-regulated compared to the control while hsp22 and totA were up-regulated.
In the exposed males, the number of F1 pupae was decreased compared to the corresponding control group, but that was only significant for the short-term exposure group.
The authors conclude that the study showed the in vivo effects of short-term and long-term exposure to extremely low frequency magnetic field on the male fruit fly.