Geology topics

Charles O. Knowles

Publications and source records attributed to Charles O. Knowles.

3 recordsLinked to original sources

USGS1968

Some enzymatic properties of brain Acetylcholinesterase from bluegill and channel catfish

Using a manometric technique an acetylcholinesterase (EC 3.1.1.7, acetylcholine acetyl-hydrolase) was demonstrated in brain tissue from the bluegill, Lepomis macrochirus Rafinesque, and the channel catfish, Ictalurus punctatus (Walbaum). The activities were 19 and 37&ensp;μmoles acetylcholine hydrolyzed/milligram protein per hour for the bluegill and channel catfish enzymes, respectively. The optimum substrate concentration for the hydrolysis of acetylcholine was 10&ensp;m M for the enzymes from both species. Generally, the catfish acetylcholinesterase was somewhat more susceptible than the bluegill to the inhibitors tested; however, the bluegill enzyme was more susceptible to inhibition by malathion and malaoxon.

Journal of the Fisheries Research Board of Canada↗

USGS1968

Electrophoretic separation of fish brain esterases

Fish brains were homogenized in an all-glass Potter-Elvehjem-type tissue grinder in 40% sucrose solution. The homogenate concentration was 10 brains/ml for both the bluegill and channel catfish. The brei was centrifuged at 34,700 g for 30 min at 5 C, and 30 J.lliters of the supernatant were used per column for electrophoresis.

Journal of the Fisheries Research Board of Canada↗

USGS1968

Degradation of organophosphates by fish liver phosphatases

Liver homogenates of bluegill, Lepomis macrochirus Rafinesque, and channel catfish, Ictalurus punctatus (Walbaum), were shown by a manometric technique to contain soluble enzymes capable of degrading di iso propyl phosphorofluoridate (DFP) and 2,2-dichlorovinyl dimethyl phosphate (dichlorvos). Hydrolysis of the compounds was greatest in the presence of the manganic ion. Tentative identification of certain of the hydrolysis products suggested that cleavage of the anhydride bond was a degradation pathway for DFP and dichlorvos in vitro under the assay conditions employed. Substrate summation, inhibition, and activation experiments failed to clearly indicate more than a single enzyme hydrolyzing DFP and dichlorvos in the two fish.

Journal of the Fisheries Research Board of Canada↗