. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ACTIVATION OF THE PROTHORACIC GLAND 511 the incorporated grains which spread in the cytoplasm gathered each other and formed large grains which corresponded to the secretory substance (Fig. 19) and were released to the hemolymph (Fig. 20). The grains which appeared in the cytoplasm migrated to the hemolymph. They were not released from the cytoplasm in intact clusters of grains, but in small grains (Fig. 20). This agreed with the results of electron microscopy. The time course obtained by counting the grains also showed the
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ACTIVATION OF THE PROTHORACIC GLAND 511 the incorporated grains which spread in the cytoplasm gathered each other and formed large grains which corresponded to the secretory substance (Fig. 19) and were released to the hemolymph (Fig. 20). The grains which appeared in the cytoplasm migrated to the hemolymph. They were not released from the cytoplasm in intact clusters of grains, but in small grains (Fig. 20). This agreed with the results of electron microscopy. The time course obtained by counting the grains also showed the results of migration clearly. The amount of grains in the hemo- lymph increased gradually with the decrease of the grains in the cytoplasm. It is unclear whether the large grains made up of small grains corresponded to the cho- lesterol molecules or to ecdysone. These results show that cholesterol is incorporated into the prothoracic glands from the hemolymph, and then is secreted into the hemo- lymph as small grains in response to need for ecdysone. Ecdysone biosynthesis in the prothoracic glands in vivo. Ecdysone biosyn- thesis was examined at first in the intact body of the diapausing and post-diapausing prepupae after being injected with 14C-cholesterol. In the diapausing prepupae, ecdysone biosynthesis was not found (Fig. 21, open circle). On the contrary, in the post-diapausing prepupae, high radioactivity was found in the fractions 41 and 51 which were demonstrated to be /?-ecdysone and a-ecdysone, respectively (Fig. 21, closed circle). In Monema flavescens, the existence of both a- and /?-ecdysones were clearly demonstrated in vivo. To examine the synthetic site of ecdysones, ligature treatments were then carried out in the post-diapausing prepupae (Fig. 22). Diapausing prepupae were also used as controls. In the anterior part with the prothoracic glands, a- and (3- ecdysones were clearly biosynthesized (Fig. 22, open circle). The amount of (3-. FIGURE IS. Histochemical
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
