Toxicology of Cupric Salts on Honeybees. V. Gluconate and Sulfate Action on Gut Alkaline and Acid Phosphatases
| Autor: | I. Kruk, Michel Bounias, M. Nectoux, D. Popeskovic |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Copper Sulfate
Health Toxicology and Mutagenesis Radical Acid Phosphatase Kinetics Phosphatase chemistry.chemical_element Gluconates Oxygen Toxicology chemistry.chemical_compound Animals Parasites Sulfate Analysis of Variance Chromatography Quenching (fluorescence) Public Health Environmental and Occupational Health Substrate (chemistry) Biological activity General Medicine Bees Alkaline Phosphatase Pollution Fungicides Industrial Intestines chemistry Luminescent Measurements Linear Models |
| Zdroj: | Ecotoxicology and Environmental Safety. 35:67-76 |
| ISSN: | 0147-6513 |
| Popis: | Some aspects of putative nontarget effects of cupric ions systemically fed to honeybees against their parasite mite Varroa jacobsoni have been investigated on the host phosphatases. The alkaline and acid forms extracted from the guts of worker bees exhibited substrate-inhibition features. Upon detailed kinetic analysis, cupric organic salts indicate activation effects at concentrations of about 1 mM. Concentrations up to 10 mM (alkaline form) and 25 mM (acid form) induced no important changes, except a partial quenching of the substrate-inhibition process, characterized by a wide increase in the constant of apparent inhibitory binding of substrate to the enzyme-substrate complex. Partial purification gave a single alkaline form with quite similar kinetic behavior in the absence of natural ions as in crude extracts. Cupric gluconate and sulfate demonstrated similar patterns, except an increase of the apparent Hill coefficient by sulfate only. The substrate constant of acid phosphatases was decreased at high cupric gluconate doses while its maximum velocity was biphasically increased (with observed maximum at 1 mM), resulting in a sustained activation. Chemiluminescence studies revealed that cupric ion activation is counteracted by oxygen radicals generated by cupric ions and also, in vitro, by the artificial substrate para-nitrophenylphosphate. The para-nitrophenol molecules released from the reaction are therefore responsible for biphasic effects selectively observed with gluconate salts. In apicultural practice, neither blockade of activity nor dramatic changes are to be expected at doses administered to bees against the parasite. |
| Databáze: | OpenAIRE |
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