raw dataset for MS1.xls

The dataset contains gill Na⁺/K⁺-ATPase and H⁺-ATPase activity as well as plasma Na and Cl content and arterila blood pH for the samples from lake/river side sampling, artificial lake water and ion-poor water acclimation. 

Gill Na⁺/K⁺-ATPase activity was measured on crude gill

homogenates according the protocol outlined by McCormick (1993). The cocktail used for measuring H⁺-ATPase activity was the same as that used for Na⁺/K⁺-ATPase, except that it also included 5 mmol l−1 sodium azide (Sigma-Aldrich) and 0.5 mmol l⁻¹ ouabain (to reduce background ATPase activity). Gill H⁺-ATPase activity was calculated by subtracting N-ethylmaleimide-sensitive activity from total activity and expressed as μmol ADP mg–1 protein h^–1. Total protein in the homogenate was measured using Bradford reagent (Sigma-Aldrich) with bovine serum albumin standards (Bradford, 1976). All assays were run in triplicate and the coefficient of variation among replicates was <10%.

For analysis of plasma Na⁺ and Cl⁻ concentration, plasma

samples were thawed at room temperature and diluted 2000 times with ultrapure water (MilliQ® water purification system). Plasma Na⁺ concentration was determined by using flame atomic absorption spectrophotometry (SpectrAA-220FS, Varian) and certified NaCl standards. Plasma Cl⁻ concentration was measured spectrophotometrically according to Zall et al. (1956) using certified NaCl standards.

The fish was laid upside down on the dissection table and an arterial blood sample was taken from the dorsal aorta accessed through the mouth using a 23 gauge needle

and 1 ml disposable syringe.