The effects of temperature and thermal acclimation upon the osmotic properties and nonelectrolyte permeability of liver and gill mitochondria from rainbow trout (Salmo gairdneri)

Abstract

Thermal acclimation of rainbow trout (Salmo gairdneri) taken from 20 degrees C to 7 degrees C resulted in adaptation of mitochondrial function, as evidenced by increases in the specific activities of NADH- and succinate-cytochrome c reductase of 1.93- and 2.7-fold respectively. Mitochondria from both gill and liver obeyed the Boyle-van't Hoff relationship in the range from 400 to 60 mosM. Thermal acclimation had no effect on the osmotic properties of liver mitochondria, whereas gill mitochondria from cold-acclimated trout were more sensitive to osmotic swelling than mitochondria from warm-acclimated individuals. The non-electrolyte permeability of liver mitochondria was assessed by optically monitoring mitochondrial swelling rates in isosmotic solutions of urea, glycerol, mannitol and glucose. Two parameters of mitochondrial swelling were determined: (a) initial swelling rates, d(1/A)dt, and (b) swelling constants, ks, derived from the time required to swell a fixed volume. Regardless of the assay temperature or the permeant employed, liver mitochondria from cold-acclimated trout exhibited greater initial swelling rates than mitochondria from warm-acclimated trout, indicating properties of temperature-compensated permeability. The apparent ranking of nonelectrolyte permeabilities was urea greater than glycerol greater than mannitol greater than glucose. ks values for urea and glycerol from cold-acclimated trout were greater than values typical of warm-acclimated populations; however ks values for glucose and mannitol were not influenced by thermal acclimation. Regardless of the permeant considered, activation energies for ks values were 3- to 5-fold greater than those for initial swelling rates. The time course of mitochondrial swelling consists of two components, an initial rapid swelling phase characterized by a half-life of 3-12 seconds, and a slower swelling phase characterized by a half life of 1-6 minutes. Initial swelling rates, which approximate the rapid swelling component, are considered to be the least ambiguous index of permeability, whereas ks values are more complex and strongly influenced by the slower swelling component.

Short term temperature acclimation in myofibrillar ATPase of a stenotherm Salmo gairdneri Richardson and an eurytherm Carassius auratus

“…Although trout have been described as stenothermal (Varley, 1967), aspects of their metabolism have been shown to adapt to temperature (Peterson & Anderson, 1969). Exposure to cold has been shown to cause increases in activity of proteolytic enzyme activity (Owen & Wiggs, 1971;Milanesi & Bird, 1972;Whitmore & Goldberg, 1972), fatty acid utilization (Dean, 1969), glucose metabolism (Hochachka & Hayes, i 962) and some mitochondria1 enzymes (Hazel & Schuster, 1976) for a variety ofspecies oftrout.…”

Cold Adaptation in Ectotherms: Regulation of Membrane Function and Cellular Metabolism

“…Furthermore, mitochondrial lipid extracts from 5°C-acclimated goldfish were more effective in reactivating a lipid-depleted preparation of succinate dehydrogenase than comparable extracts from 25°C-acclimated fish (Hazel 1972), suggesting a role for the lipid milieu in modifying the activity of membrane-associated enzymes in a temperature-adaptive fashion. Additionally, the permeabilities of trout liver mitochondria to glucose, glycerol, and urea determined at 5°C in 7 °C_ acclimated trout were equivalent to, or greater than, permeabilities measured at 20°C in 20°C-acclimated trout, indicating nearly perfect compensation of barrier properties (Hazel and Schuster 1976). Compensatory adjustments in water and nonelectrolyte permeabilities have also been reported for toad urinary bladder (Parisi et al 1976) and liposomes derived from total phospholipids of trout liver (Hazel 1979).…”