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Temporal changes in enzyme activity and mRNA levels during thermal challenge in white sucker
Author(s) -
Hardewig I.,
Dijk P. L. M.,
Leary S. C.,
Moyes C. D.
Publication year - 2000
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2000.tb02095.x
Subject(s) - biology , enzyme , acclimatization , enzyme assay , anaerobic exercise , heat shock protein , cytosol , messenger rna , biochemistry , medicine , endocrinology , ecology , physiology , gene
In the early phases of warm acclimation in white sucker Castotomus commersoni , white muscle lactate and succinate, two endproducts of anaerobic energy metabolism, remained unchanged, indicating that energetic imbalance is not a prerequisite for alterations in enzyme levels. The changes in enzyme activities did not correlate with changes in mRNA levels, which argues against transcriptional regulation of enzyme expression under these conditions. The observed induction of cytosolic heat shock protein 70 suggests that the early phases of acclimation to strongly increased temperatures are dominated by enhanced protein degradation, leading to a new balance between synthesis and degradation and, therefore, new steady‐state enzyme concentrations.