Studies on the functional localization of digestive system in silkworm larva, Bombyx mori L.

(IX.) Absorption and distribution of iron in midgut epithelium

Abstract

In order to know the functional differentiation of the midgut of silkworm larva, absorption and distribution of irons were investigated histochemically.
In midgut epithelium cells of the larva, irons present in both ferrous and ferric forms. But the reactions of these irons are quite weak in the cells of the larva reared normally. When they are administrated ferrous or ferric chloride with diet, or mulberry leaves, adding a small quantities of sucrose for promoting their appetite, the reactions of Fe⁺⁺or Fe⁺⁺⁺ become strong.
There are some local differences in distribution of irons in the tissue. Considering from the observations, they are more absorbed and stored in the cells of the posterior portion than in the middle and anterior portions. The anterior portion except the frontest end absorbs a quite small quantities of irons
.A high activity of catalase presents in the posterior portion of midgut of the larva cultured normally. In the middle and anterior portion, the activities are rather weak. When ions are given per os, catalase activities in the gut become higher. In this case, the posterior portion shows the highest activities than the other portions.