L-selenomethionine

ChEBI · EMBL-EBI ↗ · Källdatum saknas · Källans villkor

The L-enantiomer of selenomethionine.

GerhartAllyson K; JanzDavid M · Toxicity of Aqueous L-Selenomethionine and Tert-Butyl Hydroperoxide Exposure to Zebrafish (Danio rerio) Embryos Following Tert-Butyl Hydroquinone Treatment ↗ · 29 aug. 2019 · Källans villkor

Embryos were randomly distributed into glass petri dishes containing 40 mL of test solution. Each petri dish contained 20 embryos, with 9–12 replicate petri dishes in each exposure group. Exposure proceeded for 5 days in facility water alone (control embryos) or facility water spiked with nominal SeMet concentrations of 5, 25, 125, and 625 µg Se/L. To maintain water quality, 75% solution changes were performed daily and any dead embryos were removed.

GerhartAllyson K; JanzDavid M · Toxicity of Aqueous L-Selenomethionine and Tert-Butyl Hydroperoxide Exposure to Zebrafish (Danio rerio) Embryos Following Tert-Butyl Hydroquinone Treatment ↗ · 29 aug. 2019 · Källans villkor

SeMet exposures ≥ 25 µg/L significantly decreased embryo survival, with percentages of 39.6% ± 7.6%, 52.9% ± 10.1%, and 95.6% ± 3.4% (p ≤ 0.024), compared to 2.50% ± 1.2% in the controls. An LC50 value of 67.9 µg/L (95% CI = 43.4–108 µg/L) was calculated for SeMet-induced mortality (Figure 1). From a time-course perspective, embryo mortality started to increase on the third day, reached a maximum on the 4th day, and was usually followed by a slight decrease on the 5th day of exposure.

GerhartAllyson K; JanzDavid M · Toxicity of Aqueous L-Selenomethionine and Tert-Butyl Hydroperoxide Exposure to Zebrafish (Danio rerio) Embryos Following Tert-Butyl Hydroquinone Treatment ↗ · 29 aug. 2019 · Källans villkor

Representative images of the deformities observed in this study can be found in Figure 2. SeMet exposures ≥25 µg/L significantly increased the percentage of total deformities, with percentages of 44.7% ± 7.8% (p = 0.019) and 62.3% ± 14% (p ≤ 0.0185) compared to 15.2% ± 2.9% in the controls. An EC50 value of 43.8 µg/L (95% CI = 21.4–138 µg/L) was also calculated for SeMet-induced deformities (Figure 3).

GerhartAllyson K; JanzDavid M · Toxicity of Aqueous L-Selenomethionine and Tert-Butyl Hydroperoxide Exposure to Zebrafish (Danio rerio) Embryos Following Tert-Butyl Hydroquinone Treatment ↗ · 29 aug. 2019 · Källans villkor

SeMet exposure had no significant effect on mean time to hatch (Figure S3); however, a significant reduction in embryo hatchability was observed at concentrations ≥25 µg/L, with percentages of 61.3% ± 8.7%, 60.0% ± 8.1%, and 24.4% ± 8.0% (p ≤ 0.0073) compared to 97.5% ± 1.2% in the controls (Figure S4).

GerhartAllyson K; JanzDavid M · Toxicity of Aqueous L-Selenomethionine and Tert-Butyl Hydroperoxide Exposure to Zebrafish (Danio rerio) Embryos Following Tert-Butyl Hydroquinone Treatment ↗ · 29 aug. 2019 · Källans villkor

Total Se quantified in pooled larvae following 5 days of aqueous exposure at concentrations of 5, 25, 125, and 625 µg Se/L had mean total Se tissue concentrations of 34.2, 144, 264, and 291 µg Se/g dry mass (d.m.), respectively, compared to 2.98 µg/g d.m. in control embryos, indicating bioaccumulation in larvae in a concentration-dependent manner. Test solutions were also analyzed for total Se using ICP-MS to verify exposure concentrations (Table 1). Measured concentrations were all in agreement with nominal concentrations.

GerhartAllyson K; JanzDavid M · Toxicity of Aqueous L-Selenomethionine and Tert-Butyl Hydroperoxide Exposure to Zebrafish (Danio rerio) Embryos Following Tert-Butyl Hydroquinone Treatment ↗ · 29 aug. 2019 · Källans villkor

No differences were observed between embryos pre-treated with tBHQ and embryos exposed to either SeMet or tBOOH alone for all endpoints evaluated in the present study. Here we offer a few potential reasons for this observation:

GerhartAllyson K; JanzDavid M · Toxicity of Aqueous L-Selenomethionine and Tert-Butyl Hydroperoxide Exposure to Zebrafish (Danio rerio) Embryos Following Tert-Butyl Hydroquinone Treatment ↗ · 29 aug. 2019 · Källans villkor

In the present study, lordosis (a form of skeletal curvature) was excluded from the deformity calculations due to an abnormally high incidence within both the control and tBHQ treatment groups (Figure S10,11), as it was not believed to be reflective of Se exposure. Interestingly, the frequency of lordosis was lesser in the SeMet and tBOOH exposure groups compared to control and tBHQ groups. It is uncertain why the rate of lordosis was highest in both control treatments but seemed to decrease in frequency in the other treatment groups; however, it may have been related to either poor egg quality as a result of using an older zebrafish breeding stock, or some sort of nutritional deficiency.

GerhartAllyson K; JanzDavid M · Toxicity of Aqueous L-Selenomethionine and Tert-Butyl Hydroperoxide Exposure to Zebrafish (Danio rerio) Embryos Following Tert-Butyl Hydroquinone Treatment ↗ · 29 aug. 2019 · Källans villkor

The observed results were influenced by the duration and developmental stage of exposure. In the present study, embryos were pre-treated for 4h with 100 µg/L tBHQ immediately following collection. Previous work by Timme-Laragy et al. [17] treated embryos (at 48 or 72 hpf) with tBHQ for 4h. Another study conducted a 6h tBHQ treatment in 7-day-old zebrafish larvae [16], while Arnold et al. [12] pretreated zebrafish embryos (within 2 hpf) for 24h with the antioxidant N-acetylcysteine (NAC). Different exposure regimes will likely result in different responses.

GerhartAllyson K; JanzDavid M · Toxicity of Aqueous L-Selenomethionine and Tert-Butyl Hydroperoxide Exposure to Zebrafish (Danio rerio) Embryos Following Tert-Butyl Hydroquinone Treatment ↗ · 29 aug. 2019 · Källans villkor

To the best of our knowledge, there is no previous research that has looked at the production of deformities in fish embryos following exposure to these chemicals (tBHQ and tBOOH). Therefore, more research is required to better understand whether these pharmacological agents are helpful/suitable for investigating the mechanism of Se toxicity.