Chernyshev A.V.1, Kotsyuba E.P.1, Okazaki R.K.2 2018. Thermal induction of heat shock proteins Hsp70 and Hsp90 in tissues of the nemerteans Lineus alborostratus Takakura, 1898 and Quasitetrastemma stimpsoni (Chernyshev, 1992) // Invertebrate Zoology. Vol.15. No.1: 51–70 [in English].
1 A.V. Zhirmunsky Institute of Marine Biology, National Scientific Center of Marine Biology Far East Branch, Russian Academy of Sciences, Vladivostok 690041 Russia. E-mail: email@example.com
2 Department of Zoology, Weber State University, 1415 Edvalson Street, Dept. 2505, Ogden, UT 84408-2505, USA.
ABSTRACT: Intertidal ribbon worms in the phylum Nemertea live in environments where temperature and salinity can vary widely depending on the tidal fluctuations. Heat shock proteins (Hsps) are expressed by cells in their physiological responses to these changing abiotic factors. To understand the role of Hsps, the presence of Hsp70 and Hsp90 was determined by western blotting in two nemertean species, Lineus alborostratus and Quasitetrastemma stimpsoni after 2- and 4-h thermal stress. Additionally, their tissue distributions of these Hsps were detected by immunohistochemistry. Both Hsps were detected in the two nemertean species. In L. alborostratus, Hsp70 and Hsp90 immunoreactivities were detected in the body wall, specifically in the epidermal and cutis cells, as well as in the epithelia of the stomach and proboscis; Hsp immunoreactivities in these cells and tissues appeared higher in the thermally-stressed nemerteans compared to the controls. For both the control and thermally-stressed Q. stimpsoni, Hsp70 and Hsp90 were localized in the epidermis, while the stomach epithelium and neurons of the lateral nerve cord showed low immunoreactivities in the thermally-stressed worms. In thermally-stressed L. alborostratus, the proboscis showed a marked increase of Hsp70 and Hsp90 immunoreactivity. Active immunoreactivities were observed in the supra-epidermal granules in both ribbon-worm species, especially Q. stimpsoni. Accumulation of Hsp70 and Hsp90 in the body wall and the gastric epithelium of nemerteans may indicate their importance during their physiological response to thermal stress.
KEY WORDS: Hsp70, Hsp90, thermal stress, nemerteans, immunohistochemistry.