UVB radiation prevents skeleton growth and stimulates the expression of stress markers in sea urchin embryos.
Ozone depletion results in an increased flux of biologically damaging radiations reaching the earth. Although ultraviolet (UV) penetration is attenuated by the seawater, harmful effects can be still observed at low depths where sea urchin embryos are living. We have used Paracentrotus lividus embryos to study the impacts of UV radiation on their development. Blastula cultures were exposed to different doses of UVB (312 nm) radiations and the resulting endpoint effects were evaluated in terms of embryonic morphological abnormalities, variations in specific gene expression, and changes in the levels of stress proteins. We found that embryos were moderately sensitive to 50 J/m2 UVB radiation; an increase in the number of developmentally delayed and malformed embryos was detected when increasing doses, up to 1000 J/m2, were used. Major developmental defects, observed 24 and 48 h after exposure, consisted in the failure of skeleton elongation and patterning. Accordingly, we found a reduction in the number of primary mesenchyme cells that expressed Pl-SM30, a gene coding for one of the specific matrix proteins of the skeleton. The morphological effects observed 1, 24, and 48 h after exposure were correlated with a dose-dependent increase in the level and in the activation of two recognized stress markers, namely hsp70 and p38 MAPk, respectively, consistent with their role in mediating cellular response to stress and suggesting a function in embryo survival.
Bonaventura
Rosa
R
Consiglio Nazionale delle Ricerche, Istituto di Biomedicina e Immunologia Molecolare "Alberto Monroy", Sezione Biologia dello Sviluppo, Palermo, Italy.
Poma
Veronica
V
Costa
Caterina
C
Matranga
Valeria
V
D000016:Abnormalities, Radiation-Induced / Q000209:etiology* / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism; D001846:Bone Development / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004789:Enzyme Activation / Q000528:radiation effects; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D018384:Oxidative Stress / Q000528:radiation effects*; D047328:Paracentrotus / Q000196:embryology* / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects; D011829:Radiation Dosage; D014466:Ultraviolet Rays / Q000009:adverse effects*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
D015415:Biomarkers; D018840:HSP70 Heat-Shock Proteins; D048051:p38 Mitogen-Activated Protein Kinases