Induction of heat-shock (stress) protein gene expression by selected natural and anthropogenic disturbances in the octocoral Dendronephthya klunzingeri

Previously it was found that the expression of selected heat-shock proteins is upregulated in corals after exposure to elevated temperature. We publis hed that HSPs are suitable markers in sponges to monitor the degree of envi ronmental stress on these animals. In the present study the heat-shock prot eins (HSPs) with a molecular weight of 90 kDa have been selected to prove t heir potential usefulness as biomarkers under controlled laboratory conditi ons and in the field. The studies have been performed with the octocoral De ndronephthya klunzingeri from which the cDNA coding for HSP90 was cloned fi rst. The expression of the HSP90 gene is upregulated by thermal stress; tre atment of the animals for 2 h at 4 degrees C below or above the ambient tem perature resulted in a >4.5-fold higher steady-stare level of the respectiv e mRNA. Also animals taken from stressed locations in the field showed an i ncreased expression. The amount of HSP90 protein in D. klunzingeri was foun d to be strongly increased under thermal stress, or exposure to polychlorin ated biphenyl (congener 118), but not after treatment with cadmium. Field s tudies revealed that samples taken from a nonstressed area have a low level of HSP90, but those collected from locations at which the corals are under physical stress (sedimentation through landfilling) show a high expression of HSP90. It is concluded that the chaperone HSP90 might become a suitable biomarker to monitor environmental stress on corals. (C) 2000 Elsevier Sci ence B.V. All rights reserved.