|標題:||靜態電磁場對線蟲之影響 : 由細胞自然凋亡所引起之行為遲緩及加速老化|
Effect of static electromagnetic field on Caenorhbditis elegans : reduction of mobility through apoptosis and acceleration of aging process
Huang, Gue-Wha Steven
Adult Caenorhabditis elegans were treated by static electromagnetic fields (static EMF) and the crawling speed was measured. Reduced mobility was observed when magnetic flux density stronger than 150 mT and the duration of treatment longer than 4 days. Eighty percents reduction of mobility occurred when the flux density reached 200 mT and duration of treatment extended to 8 days. Twenty-six differentially expressed genes among apoptosis, oxidative stress, and cancer were identified using quantitative real-time RT-PCR, indicating a globally molecular consequence responding to static EMF. Induction of apoptosis was verified by Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and immunostaining using antibody against ced-3 gene product. Mutations at genes involved in major apoptotic pathway, i.e. ced-3, ced-4, and ced-9, abolished this static EMF-induced mobility reduction; consistent with the hypothesis that apoptosis is associated with the static EMF-induced mobility reduction. The current study investigated the possible effect of static electromagnetic field (SEMF) on the development and aging process of C. elegans. Nematodes were grown under SEMF of strength from 0 to 200 mT. Development time and lifespan was recorded. Lifespan was reduced from 31 days to 25 days for wild-type nematode. Treatment of 200 mT SEMF reduced development time fro 20% from L2 to L3 stage, 23% from L3 to L4, and 31% from L4 to young adult. Over expressions of clk-1, lim-7, unc-3, and age-1 was verified by quantitative real time RT-PCR. Surveillance of total development time for mutant nematodes elicited the significant reduction for lin-4, lin-14, lin-41, and lim-7, but not for let-7, clk-1, unc-3, and age-1 mutant strains. Lifespan analysis revealed that let-7, unc-3, age-1 was not affected by SEMF treatment. SEMF accelerated the development and shortened the lifespan of nematode through pathways associated with let-7, clk-1, unc-3, and age-1.
|Appears in Collections:||Thesis|