Figure 2

PlOvoA expression profile and response to environmental stress conditions.

(A) PlOvoA expression during embryo development. Eggs and embryos collected at different development stages (virgin eggs VE, fertilized eggs FE, early blastula EB, swimming blastula SB, prisma Pr and pluteus Pl) were examined for gene expression by Real Time qPCR. Fold differences in the expression levels of PlOvoA with respect to the reference gene Pl-Z12-1 were expressed in percentage with respect to highest levels of mRNA in VE (100%). *represents the significance respect to VE, **P < 0.01, ***P < 0.001. #represents the significance respect to Pr, ^##P < 0.01. (B) Pl OvoA expression analysis in developing embryos after metal treatment. FE were treated with 1, 5, 10 μM Cd²⁺ and 36 μM Mn²⁺ and different developmental stages were examined for the transcriptional expression of PlOvoA. Data are reported as a fold difference in PlOvoA expression levels, compared to control (mean ± SEM), embryos developed in seawater without metals. Fold differences greater than ± 2 (see dotted horizontal guidelines at values of 2 and −2) were considered significant. (C) Ovothiol levels in developing embryos after metal treatment. FE were treated with 5 μM Cd²⁺ and SB and Pr were examined for ovothiol production. Data are reported as μmol ovothiol/mg of embryos. Results are representative of 3 independent experiments and expressed as means ± SEM and analyzed by unpaired t-test. *represents the significance respect to the control, **P < 0.01. D. PlOvoA expression analysis in developing embryos after maternal exposure to O. cf ovata bloom. Sea urchin females, exposed to Ostreopsis cf. ovata bloom in July at Gaiola site, were collected in October and fertilized. Different developmental stages (EB, SB, Pr and Pl) were examined for PlOvoA expression. Data (mean ± SEM) are reported as a fold difference in PlOvoA expression levels, compared to control embryos derived from sea urchins collected at control site. Fold differences greater than ± 2 were considered significant.