Effects of lead on delta-aminolevulinic acid dehydratase activity, growth, hemoglobin content, and reproduction in Daphnia magna
The effects of continuous exposure to lead for various periods and recovery in clean water on delta-aminolevulinic acid dehydratase (ALA-D) activity, hemoglobin content, growth, and reproduction were studied in Daphnia magna. Steady-state inhibition of ALA-D activity was reached within 2 days in 16, 64, and 256 micrograms Pb liter-1, but restoration in clean water was prolonged in relation to previous exposure. In spite of the inhibition of ALA-D activity hemoglobin content increased after 2 days in 16 and 24 micrograms Pb liter-1. Furthermore, hemoglobin content in previously exposed animals increased during recovery in clean water. Maximum hemoglobin content (2.9 times control value) was found after 2 days recovery of animals exposed to 64 micrograms Pb liter-1. These findings suggest that some enzyme(s) other than ALA-D in the biosynthetic pathway of hemoglobin formation is (are) more sensitive to lead. Growth, in contrast to reproduction, was stimulated by low concentrations of lead (less than 64 micrograms Pb liter-1), although in 256 micrograms Pb liter-1 growth was also significantly impaired. After 19 days the 16 and 50% reproductive impairment concentrations were less than or equal to 1 and 10 micrograms Pb liter-1, respectively.
- Research Organization:
- Univ. of Goeteborg, Sweden
- OSTI ID:
- 5261986
- Journal Information:
- Ecotoxicol. Environ. Saf.; (United States), Vol. 2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DAPHNIA
GROWTH
HYDRO-LYASES
ENZYME ACTIVITY
LEAD
BIOLOGICAL EFFECTS
AMINOLEVULINIC ACID
CHRONIC EXPOSURE
HEMOGLOBIN
OXYGEN
REPRODUCTION
SEAWATER
AMINO ACIDS
ANIMALS
AQUATIC ORGANISMS
ARTHROPODS
BRANCHIOPODS
CARBON-OXYGEN LYASES
CARBOXYLIC ACIDS
CRUSTACEANS
ELEMENTS
ENZYMES
GLOBIN
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
INVERTEBRATES
LYASES
METALS
NONMETALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PIGMENTS
PORPHYRINS
PROTEINS
WATER
560304* - Chemicals Metabolism & Toxicology- Invertebrates- (-1987)