Growth and Metabolism of Chick Embryo Muscle Cultures

Abstract

Malathion and malaoxon inhibited growth (cell number, protein, DNA) of chick embryo pectoral muscle cultures. Low-protein phosphate-buffered medium with pesticide was more toxic than high-protein, carbon dioxide-buffered medium. Growth was also inhibited by parathion and paraoxon. Malathion, but not malaoxon, inhibited the respiration of cells, tissue homogenates, and mitochondrial fractions. Oxygen consumption of intact cells was inhibited by malathion under conditions in which it was toxic to growth. The results suggested oxidation of α-ketoglutarate as one site of malathson action. Acetylcholinesterase (AChE) activity was studied by spectrophotometry, cytochemistry, and gel electrophoresis. Muscle cultures and embryo muscle tissue had similar AChE isozymes. Cells grown with malaoxon had less AChE activity than those grown with malathion. Levels of AChE activity did not correlate with toxicity of the organophosphorus agents.