Plasticity and stressor-specificity of osmotic and heat shock
responses of gillichthys mirabilis gill cells.
K[umlaut]ultz, Dietmar.
Department of Zoology, Oregon State University, Cordley Hall 3029,
Corvallis, OR 97331-2914, USA
APStracts 3:0145C, 1996.
Short-term effects of osmotic and heat shock on proteins of
Gillichthys mirabilis gill cells were analyzed. The protein synthesis
rate (PSR) of gill cells was influenced by hyperosmotic shock (335
-> 635 mosmol/kg H2O) and heat shock (25 -> 37 degrees C)
but not by hypoosmotic shock (335 -> 190 mosmol/kg H2O). Between
4-6 h after hyperosmotic shock, gill cell protein synthesis was
inhibited relative to controls in serum-free medium, but increased
threefold over control values in medium supplemented with 10% serum.
Serum-dependent stimulation of PSR was also observed after heat
shock. Using two-dimensional electrophoresis, 21 proteins induced
after hyperosmotic shock, 14 after hypoosmotic shock, and 16 after
heat shock were found. The osmotic shock response of gill cells was
highly stressor-specific because only 5 or 3 proteins that were
induced after hyperosmotic or hypoosmotic shock, respectively, were
identical with proteins induced in response to heat shock. Heat shock
protein (HSP) 70 isoforms were only induced after heat shock but not
in response to osmotic shock. In gill and kidney epithelium, the
transcription factor c-Jun was modified within 30 min after transfer
of whole fish from 1086 mosmol/kg H2O to 5 or 2172 mosmol/kg H2O, but
osmotic shock in vitro had no effect on c-Jun in isolated gill cells.
Ion substitution experiments revealed that the increase of PSR after
hyperosmotic shock in serum-supplemented medium significantly
depended on an elevation of extracellular [Na+]. These data provide
evidence for the plasticity and stressor-specificity of osmotic and
heat shock responses of fish gill cells.
Received 30 November 1995; accepted in final form 23 April 1996.
APS Manuscript Number C716-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 8 May 96