Abstract
The purpose of the present experiments is to clear the mechanisms on the pigment formation of the serosal cell and of the marking of the newly hatched larva of the silkworm in some different environments. The eggs of several mutants are incubated in a low and high temperatures and also exposed to the illumination and sun light. The dosages of 3-hydrroxykynurenine, pigments in the serosal cells and in the marking of the newly hatched larvae have been carried out by the colorimetric and spectrophotometric methods. The results obtained are as follows:
1. The amount of melanin pigment in the newly hatched larvae in the low incubation temperature (15°C) is larger than that of the high temperature (26-27°C), and this phenomenon is plausibly thought to be due to the difference on the physiological and biochemical conditions in the eggs produced by the difference of the temperature.
2. The disintegration of the pigments which has located at the corner of the serosal cell in the hibernating egg is accelerated under the light exposure in the process of the incubation. It is thought that the light exposure is one of the factors having relation with the disintegration of the pigment in serosal cell.
3. By exposing to light the amount of 3-hydroxykynurenine in the egg descreases, and the pigments in the serosa increase. These phenomena are thought to be due to the acceleration of the enzyme activity which acts on the conversion from 3-hydroxykynuenine into serosal pigment.
4. When the sun light is exposed on the developing egg at relatively early stage, the amount of melanin pigments in the newly hatched larva decreases a little except I-a and ch strains, but the exposure at the later stage (bluished egg) increases the amount of melanin pigments.
5. The developmental velocity of the embryo is accelerated by the light exposure in the relatively earlier stage, but is not influenced by the same treatment in the later stage except ch strain.
