Abstract:

This dataset contains expression levels of different UV repair enzymes (catalase, photolyase, and superoxide dismutase) as well as buoyancy curve data for mahi-mahi (Coryphaena hippurus) embryos exposed to different durations of UVA throughout development.

Suggested Citation:

Pasparakis, C.. 2018. Expression of UV repair enzymes and relation to buoyancy change in mahi-mahi (Coryphaena hippurus) embryos. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N76T0K5T

Publications:

Pasparakis, C., Wang, Y., Stieglitz, J. D., Benetti, D. D., & Grosell, M. (2019). Embryonic buoyancy control as a mechanism of ultraviolet radiation avoidance. Science of The Total Environment, 651, 3070–3078. doi:10.1016/j.scitotenv.2018.10.093

Purpose:

To test different durations of UVA exposure on buoyancy and antioxidant and UV repair enzyme expression in embryonic mahi-mahi.

Data Parameters and Units:

qPCR data and associated amplification plots for antioxidant enzymes (catalase, SOD1, and SOD 3), UV repair enzyme (photolyase) and reference gene (EF1α) can be found in ‘qPCR data’ folder. Triplicates are labeled by gene, treatment, development time point, and triplicate number (ex: CAT_CA1). Abbreviations are as follows: Genes (CAT = catalase, PH = photolyase, SOD = superoxide dismutase); treatment (C = control; 2 = 2 hr UVR; 8 = 8 hr UVR; 21 = continuous UVR); time point (A = 13 hpf (hours post fertilization); B = 16 hpf; C = 24 hpf; D = 27 hpf; E = 38 hpf) and finally NTC = non template control. Buoyancy data (scale of -1 (complete negative buoyancy) to +1 (complete positive buoyancy) for embryos exposed to different durations of UVA can be found in ‘UVR buoyancy curve data’ folder. Buoyancy data for the ammonia excretion trials can be found in ‘Ammonia excretion buoyancy curve data”. Abbreviations for different treatments in this data set are as follows: SW = seawater only; HEA = high external ammonia (20 mM ammonia chloride); and NaCl (20 mM sodium chloride).

Methods:

Mahi embryos were exposed to different durations of UVA throughout development. Expression of antioxidant enzymes (catalase, SOD1, and SOD3) and UV repair enzyme (photolyase) were quantified in mahi embryos in different treatments and at different time points. To explore mechanisms behind buoyancy control, mahi embryos were exposed to a solution of high external ammonia (20 mM ammonia chloride) and buoyancy curves were also generated (presented as % positively buoyant). To measure buoyancy, embryos in individual crystallizing dishes were given a score ranging from −1 to +1, depending on their vertical location within the dish. Embryos floating at the surface of the dish were scored with a +1, indicating complete positive buoyancy while embryos sitting on the bottom of the dish were given a score of -1 denoting complete negative buoyancy. Embryos floating in the middle of the dish were scored on the same scale, using increments drawn on the dishes for reference. Time points were taken every hour. Hpf were estimated as exact spawning times were unknown, thus accounting for differences in negative buoyancy onset. These experiments were also run at different times of years, in different laboratory settings and with different broodstock further accounting for any inconsistencies. Buoyancy quantification was initiated once the first embryo was observed to sink out and become negatively buoyant and continued every hour up until the start of hatch period. To accommodate the high number of replicates in these studies we present data as percentage of embryos that were positively buoyant at a given time point (equivalent to a scoring of +1). There is data in the hatched column but only at later time points - the blank cells indicate no hatch had occurred. The wavelength measured in all experiments was 380 nm (due to restraints of radiometer) although the UVA light banks emit UV wavelengths between 350-400 nm.

Instruments:

UVA light bulbs for embryonic exposures were purchased from HTG Supply (HTG Supply, Callery, PA). UVA exposures were measured using a Biospherical radiometer (BioSpherical Instruments, Inc., San Diego, CA). Expression of enzymes were quantified using an Mx3005P Multiple Quantitative PCR System (Stratagene, San Diego, CA) to perform real-time qPCR on all cDNA samples with Power SYBR Green qPCR Master Mix (Thermo Fisher Scientific, Waltham, MA) as the reporter dye.

Individual Files: