Effects of UV-B radiation on development and hsp70 expression in sea urchin cleavage embryos
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A number of studies aimed to assess the health of aquatic ecosystems have focused on the dangerous effects of ultraviolet B (UV-B) radiation on marine organisms, especially those living in shallow waters such as sea urchin embryos and their larvae. We studied the effects of UV-B radiation on Paracentrotus lividus embryos at early stages of development, in laboratory experiments. Embryos at the 16-cell stage were exposed to different doses of UV-B, ranging from 10 to 800 J/m2, and the resulting morphological abnormalities were observed. In addition, putative variations in the expression of the heat shock proteins 70 (hsp70) stress marker, at the protein and mRNA levels, were evaluated. The first effective dose was 150 J/m2, producing a significant number of abnormal embryos, scored 24 h after exposure. This number increased up to 100% when the two highest doses were used (400 and 800 J/m2). Besides delays in embryonic development, the most abnormal morphology (abnormal blastula) consisted of blastula-like embryos, with cells unusually filling the blastocoelic cavity. Abnormal blastulae were not able to continue development as they were found 48 h after exposure. Some embryos with less severe abnormalities showed tri-radiate spicule rudiments, but had major defects in gut elongation. A corresponding dose-dependent increase in the hsp70 protein levels was observed in embryos exposed to different UV-B doses. Conversely, slight, if any variations were detected in the hsp70 mRNA levels for any of the doses tested, claiming for a post-transcriptional regulation of UV-B-induced stress response.
KeywordsHsp70 Expression Hsp70 Level Paracentrotus Lividus Hsp70 Protein Level Hsp70 mRNA Level
This research has been supported by the EU program UV-TOX to V. Matranga, Contract No. EVK3-CT-1999-00005. Partial support was also obtained by the ASI, Contract No. I/R/073/01. We are grateful to all the other members of the group for their helpful contributions and suggestions, and the stimulating working environment. The authors thank Mr. Davide Comacchio for assistance in maintenance of sea urchins in aquaria.
- Akimoto Y, Shiroya T (1986) Scanning electron microscopy of UV-induced abnormal morphogenesis in sea-urchin embryos (Hemicentrotus pulcherrimus). J Fac Sci Univ Tokyo Sect IV Zool 16:87–98Google Scholar
- Beiras R, Bellas J, Fernandez N, Lorenzo JI, Cobelo-Garciam A (2003) Assessment of coastal marine pollution in Galicia (NW Iberian Peninsula); metal concentrations in sea water, sediments and mussels (Mytilus galloprovincialis) versus embryo-larval bioassays using Paracentrotus lividus and Ciona intestinal. Mar Environ Res 56:531–553CrossRefGoogle Scholar
- Browman HI, Rodriguez CA, Be´land F, Cullen JJ, Davis RF, Kouwenberg JHM, Kuhn PS, MacArthur B, Runge JA, St-Pierre J-F, Vetter RD (2000) Impact of ultraviolet radiation on marine crustacean zooplankton and ichthyoplankton: a synthesis of results from the estuary and Gulf of St. Lawrence, Canada. Mar Ecol Prog Ser 199:293–311CrossRefGoogle Scholar
- Madronich S, McKenzie R, Bjorn L, Caldwell M (1998) Changes in biologically active ultraviolet radiation reaching the Earth’s surface. In: van der Leun JC, Tang X, Tevini M (eds) Environmental effects of ozone depletion: 1998 assessment. Environment programme report, United Nations, New York, pp 5–19Google Scholar
- Schröder HC, Di Bella G, Janipour N, Bonaventura R, Russo R, Müller WEG, Matranga V (2005) DNA damage and developmental defects after exposure to UV and heavy metals in sea urchin cells and embryos compared to other invertebrates. In: Echinodermata MV (ed) vol. 39. Springer, Heidelberg, pp 111–138Google Scholar