UVA-induced photo recovery during early zebrafish embryogenesis

Abstract

DNA photorepair has been widely studied in simple aquatic organisms that live in the marine environment, but is less understood in more complex species that live in freshwater. In the present study, we evaluated UVA-induced DNA photo recovery in embryonic stages of zebrafish, Danio rerio, a freshwater model species. Evaluation of UVB exposure and UVA photo recovery of zebrafish embryos revealed different UVB tolerances and capacities for UVA photo recovery at different stages of development. Effective UVA photo recovery was observed at 3 h post-fertilization (hpf), 6–7 hpf, and 12 hpf, but not in the early cleavage stage (2–32 cells). UVA photo recovery was most effective during the gastrula stage (6–7 hpf) of development, and less effective at earlier stages (e.g., 3 hpf) or later stages (e.g., 12 hpf). Embryos at the cleavage stage of development were found to be tolerant to extreme levels of UVB exposure, and possible mechanisms were discussed. For embryos at 6–7 hpf, examination of time window (or delay of UVA exposure) that would still permit recovery from UVB exposure suggested a short time period of 2 h. The transgenic fli-1 zebrafish with fluorescent vascular structure was used to show that embryos with normal morphological appearance could exhibit a disrupted vascular patterning, suggesting that this endpoint could provide a sensitive tool for detection of UV damage.

Toxicity, uptake kinetics and behavior assessment in zebrafish embryos following exposure to perfluorooctanesulphonicacid (PFOS)

“…While fli-1 transgenic zebrafish are generally a sensitive indicator of vascular abnormalities (Dong et al, 2008), we did not see a robust effect of PFOS on vascular development. The vasculature of the eye was only mildly affected in PFOS exposed animals while the body trunk vasculature was largely normal.…”

Co‐exposure of ZnO nanoparticles and UV radiation to Daphnia magna and Danio rerio: Combined effects rather than protection

“…Embryos exposed to UV radiation followed a dose‐dependent relationship, with the number of dead embryos increasing as the UV radiation dose increased. A well‐noticed effect of UV radiation on D. rerio embryos development was the occurrence of tail malformations, also observed in other studies . This specific effect can be linked with the position of the embryos at the time of exposure to the UV radiation light.…”

Molecular Response to Ultraviolet Radiation Exposure in Fish Embryos: Implications for Survival and Morphological Development

“…Previous work in zebrafish has demonstrated the capacity of UVA to activate a mechanism, the photoenzymatic repair (PER), which repairs the DNA damage caused by UVB exposure (42). The evidence of the mentioned repair system is the initial detection of photolyase enzyme in 3 hpf zebrafish embryos (43). The induction of PER partially compensates for a considerable decrease in tolerance of UVB exposure at this developmental stage (43).…”

“…The evidence of the mentioned repair system is the initial detection of photolyase enzyme in 3 hpf zebrafish embryos (43). The induction of PER partially compensates for a considerable decrease in tolerance of UVB exposure at this developmental stage (43). It is suggested that the higher UVB tolerance at the egg stage may be related to other (dark) repair mechanisms as well as possible shielding by the chorion and other maternally derived photoprotective compounds.…”