Electron Microscopic Studies on the Posterior Silk Gland of Silkworm, Bombyx mori (II)

Cytolysis of the Posterior Silk Gland of Silkworm during and after Finishing Spinning

Abstract

During spinning, cytolytic processes of the posterior silk gland start to appear. These processes are precipitously enhanced after finishing spinning and the posterior silk gland cells disappear almost completely within one or two days. Electron microscopic observation revealed the following findings: First, paired membranes appear along rough endoplasmic reticulum. Then the membranes grow gradually, enclosing rough endoplasmic reticulum, and the ER (endoplasmic reticulum) isolation bodies are formed. Probably these bodies are then transformed first to cytolysome and then to the usual lysosomes.
Histochemical examination showed that acid phosphatase reaction is positive either on the cytolysomes and lysosomes, but not on the ER isolation bodies. Cytolytic or autolytic enzymes are probably accumulated within these lysosomes and then released into cytoplasm to autolyse it.