Survivorship, development,
and DNA damage in echinoderm embryos and larvae exposed to ultraviolet
radiation (290–400 nm)
M.P. Lesser, T.M. Barry-2003
Journal of Experimental Marine Biology and Ecology, 292(1): 75-91
Abstract:
Laboratory experiments utilizing ecologically
relevant irradiances of ultraviolet radiation (UVR) known to occur in
shallow Gulf of Maine waters were conducted on the planktonic embryos and
larvae of two common benthic echinoids; the green sea urchin Strongylocentrotus
droebachiensis and the sand dollar Echinarachnius parma.
Significant decreases in survivorship were observed in freshly fertilized
embryos of both species with greater mortality in E. parma that was
associated with the absence of UVR-absorbing compounds, the mycosporine-like
amino acids. Experiments on blastula, gastrula, and prism larval stages of S.
droebachiensis also showed significant decreases in survivorship, delays
in development, and abnormal embryos and larvae associated with exposure to
UVR. Additionally, all developmental stages of S. droebachiensis
experimentally exposed to UVR resulted in significant increases in DNA
damage, measured as cyclobutane pyrimidine dimer photoproducts. The observed
delays in early cleavage and subsequent developmental stages for S.
droebachiensis are correlated with DNA damage. It is postulated that
cell cycle arrest at critical checkpoints after DNA damage, mediated by a
suite of cell cycle genes, is a component of the observed UVR induced
developmental delays.
(Department
of Zoology and Center for Marine Biology, University of New Hampshire,
Durham, NH 03824, USA, e-mail: mpl@cisunix.unh.edu)