THE STRESS-70 PROTEIN FAMILY IN DIPLOPODS - INDUCTION AND CHARACTERIZATION

To induce stress-70 proteins (hsp70), adults of the millipede Julus sc andinavius (Diplopoda) were exposed to leaf litter contaminated with d ifferent concentrations of Cd2+ (10, 30, 50 and 60 mg . kg(-1) as CdCl 2). The expression of hsp70 was investigated by semiquantitative and q ualitative biochemical methods. After SDS-gel electrophoresis and West ern blotting a subsequent digital image analysis showed that increasin g dietary concentrations of Cd2+ resulted in elevated levels of hsp70, which in turn indicated proteotoxic condition. Qualitative results we re obtained by two-dimensional gel electrophoresis. A stress-70 protei n family, similar to that of other arthropods, was detected in Julus s candinavius: at least five different proteins with an approximate mole cular weight of 68, 69, 70, 77, and 78 kDa could be distinguished afte r heat shock as well as after Cd2+ exposure.