Genetic variation in the temperature dependence of liver microsomal CYP2E1 activity, within and between species of the viviparous fish Poeciliopsis

Journal Article · Sat Dec 31 23:00:00 EST 1994 · Environmental Toxicology and Chemistry; (United States)

DOI:https://doi.org/10.1002/etc.5620140101· OSTI ID:6792548

Crivello, J F; Schultz, R J ^[1]

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1. Univ. of Connecticut, Storrs, CT (United States)

The temperature dependence of liver microsomal CYP2E1 (cytochrome P450 2E1) activity was examined in selected genotypes of the viviparous fish Poeciliopsis. Activity of this enzyme, as a function of incubation temperature, was determined by measuring 6-OH-chlorzoxazone formation from chlorzoxazone, a specific CYP2E1 substrate. Chlorzoxazone-6-hydroxylase activity was examined among five species of Poeciliopsis, as well as among nine genotypes within a species, P. monacha. Among Poeciliopsis genotypes, P. monacha contained the greatest activity, 9.5 [+-] 1.5 U with a temperature optimum (T[sub O]) of 25 C. The lowest activity was in P. occidentalis, 0.65 [+-] 0.11 U, with a T[sub O] of 27 t 28 C; P. prolifica, P. fasciata, P. lucida, and P. viriosa had intermediate levels of activities, 1.1 to 5.5 U, and T[sub O] from 25 to 31 C. To determine if metabolic differences exist within species, enzyme activity was examined from nine genotypes of P. monacha by comparing expression among P. monacha-lucida hybrids. These hybrids were given identical paternal genomes of lucida but retained the original maternal Monacha genomes sampled from wild gene pools. The greatest activity was found in genotype T70-3 P. Cw, 3.6 [+-] 0.1 U, at a T[sub O] of 29 C, and the lowest was in genotype SV73-7s, 0.40 [+-] 0.12 U, at a T[sub O] of 27 C. The other naturally occurring genotypes, M65-24, M65-26, SV73-7v, as well as the laboratory-produced synthetic hybrids, Syn4 and Syn5, had intermediate activities, 0.73 [+-] 0.38 to 2.1 [+-] 0.69 U, and T[sub O] of 25 to 27 C. No hybrid had activity levels as high as the maternal parent, P. monacha, and only one had a T[sub O] as low as either parent. Apparently the genes involved in xenobiotic activity vary widely among the closely related species of Poeciliopsis but also within species, suggesting that these phenotypes can be acted upon by natural selection.

• OSTI ID: 6792548
• Journal Information: Environmental Toxicology and Chemistry; (United States), Journal Name: Environmental Toxicology and Chemistry; (United States) Vol. 14:1; ISSN ETOCDK; ISSN 0730-7268
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540320* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
560300 -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
AQUATIC ORGANISMS
BIOLOGICAL INDICATORS
BIOLOGICAL VARIABILITY
ENZYME ACTIVITY
ENZYMES
FISHES
GENETIC VARIABILITY
HYDROXYLASES
METABOLISM
ORGANIC COMPOUNDS
OXIDOREDUCTASES
POLLUTION
PROTEINS
SENSITIVITY
VERTEBRATES
WATER POLLUTION
XENOBIOTICS