The partial purification and some properties of two sucrases of <i>Phaseolus vulgaris</i>

Abstract

EFFECT OF APHOLATE ON HOUSEFLY EGGS 357 inhibition of DNA synthesis in eggs deposited by treated insects. It is not clear, however, whether this chemical has a direct or indirect effect on DNA synthesis in the developing eggs. A direct effect could occur by transfer of the chemical from the ovaries to the eggs. On the other hand, ovarian damage, hormonal imbalance, or any one of a number of metabolic abnormalities caused by the chemical, could have an indirect effect on the synthesis of DNA in the developing eggs. It is clear, however, that the increased amount of acid- soluble deoxyribosidic compounds in eggs of apholate-treated insects was not high enough to account for the quantity of DNA that would have been incorporated into the acid-insoluble fractions under normal conditions. The absence of DNA synthesis in the developing eggs caused by apholate was also accompanied by the loss of the ability of the eggs to form lactate dehydrogenase. However, the activity of glucose 6-phosphate dehydrogenase was unaffected by the chemical, as the amount of enzyme present initially in both types of eggs remained constant during the incubation period. This again suggests that the latter enzyme could have been incorporated into the eggs by the ovaries and was not synthesized to any appreciable extent during the incubation period. It also suggests that the effects on DNA and lactate-dehydrogenase synthesis may not be signifi- cant unless the eggs deposited by flies given apholate have other more general metabolic activity. SUMMARY 1. After an initial lag period, the DNA content in normal housefly eggs increases rapidly during incubation at 370, whereas the RNA content remains almost constant.