Shick, J. M.. University of Maine, shick@maine.edu
Romaine-Lioud, S. M.. Observatoire Oceanologique European,
Gattuso, J. P.. Observatoire Oceanologique, gattuso@obs-vlfr.fr

 
UVB RADIATION STIMULATES ACCUMULATION OF MYCOSPORINE-LIKE AMINO ACIDS (MAAS) IN THE CORAL STYLOPHORA PISTILLATA, BUT NOT WHEN THE SHIKIMATE PATHWAY IS INHIBITED
 
Coral colonies maintained for four years in indoor aquaria in the near absence of UV radation contained small amounts of MAAs (<5 nmol total MAAs/mg protein). Concentrations of 10 identified MAAs (the most reported in any organism) increased linearly or exponentially when colonies were exposed to UVA (5.3 W/m2) and UVB (0.065 W/m2) (Q-Panel UVA-340 lamps) for 8 h/day in the presence of PAR (225 micromol quanta/m2/sec). Total MAA concentration reached 175 nmol/mg protein after 30 d. Palythine and mycosporine-2 glycine constituted more than half of the final total. UVB specifically stimulated MAA accumulation. After 15 d, MAA levels in colonies exposed to PAR alone (Lee 226 polycarbonate filter, 50% transmission at 400 nm) and to PAR plus UVA only (Mylar D filter, 50% T at 324 nm) did not differ (7 and 5 nmol/mg protein, respectively), while those in colonies exposed to PAR plus UVA & UVB were significantly higher (28 nmol/mg protein). Glyphosate (1 mM), an inhibitor of the shikimate pathway, eliminated the UV-induced accumulation of all individual MAAs during 7 d of exposure, providing the first experimental evidence of their synthesis via this pathway in corals.
 
Day: Tuesday, Feb. 2
Time: 03:30 - 03:45pm
Location: Sweeney Center
 
Code: SS27TU0330S