THE FORMATION OF COMPOUND EGG CHAMBERS IN A BUG (HEMIPTERA) STERILIZED WITH 6-AZAURIDINE

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Abstract
Ovaries are one of the target organs hit by the nucleic acid antimetabolite 6-azauridine. All the malformations observed are caused by the suppression of mitotic activity, which appears to be the most sensitive to the applied drug. The inhibition of mitosis in the apical trophocytes results in depletion of the nutritive tissue in older females, followed by a disturbance of previtellogenesis and activation of oocytes. The blocked mitotic multiplication of prefollicular tissue results in exhaustion of this layer followed by a disturbance of regular egg chamber formation. The inadequate separation of oocytes by follicular cells causes the arrangement of the oocytes in paired chambers, often blocking the ovariole, or the formation of compound chambers. The oocytes sharing the compound chamber either remain separated by the ooplasmalemma or merge. Eggs with adherent dwarf oocytes or giant fused double eggs are oviposited. Endomitotic DNA replication and amitotic karyokinesis of the follicular cells are not interfered with by 6-azauridine, probably owing to the nucleic acid pools contained in the haemolymph. The lecytholitic cells resorb the ooplasm utilizing the nucleic acid-rich material.