In the diapausing eggs kept continuously at 25°C, the sorbitol and glycerol content increased abruptly concomitant with the decrease in glycogen content at diapause initiation. The high level of these polyols became to decrease gradually from 120 days after oviposition, but the glycogen content remained at a low level. When transferred from 25°C to 5°C at 87 days after oviposition, the diapause eggs accumulating the high levels of these polyols showed the marked changes in carbohydrate content: an abrupt decrease in sorbitol and glycerol content with a delayed increase in glycogen. This cold-treatment caused to break diapase completely. When the eggs were kept at the programmed temperature as 1°C to -2.5°C, the polyols content in eggs at either 1°C or to -2.5°C was observed to decrease slowly compared to that at 5°C. The other hand, glycogen content increased accompanying a decrease in these polyol content. After the eggs kept continuously at -2.5°C had temporally exposed a high temperature (15°C) for 3 days at 310 days, they were incubatedat 1°C. The sorbitol and glycerol content in these eggs decreased rapidly correspond to the abrupt decrease of glycogen, although the level of polyols could be observed in the eggs having been kept at 1°C or -2.5°C.
These results suggest that the interconversion between glycogen and sorbitol might be affected by the cold conditions of different temperatures. Futhermore, the role of polyols in the diapause eggs was disccused with preservation of embryo in cold conditions.

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Growth of general bacteria, e. g., Bacillus thuringiensis, Pseudomonas aeruginosa, Staphylococcus aureus, was inhibited under the alkaline condition of digestive juice of silkworm larvae, but that of the alkaline-tolerant streptococci was not inhibited. Anti-streptococcal activity was found in macromolecular parts obtained by means of the gel-chromatography on sephadex G-75 from the fraction salting out of digestive juice. The active fraction was sensitive against the proteolytic enzymes and thermolabile at over 70°C for 15min. Therefore, the active substance seemed to be a macromolecular protein and was tentatively termed “Anti-Streptococcut Protein (ASP)”. Anti-bacterial spectrum of ASP exhibited the specific property; namely, growth of bacteria belonging to Streptococcus genus was inhibited exclusively, and mode of anti-streptococcal action was considered to be bacteriostatic. The fifth-instar larvae, administered orally the alkaline-tolerant streptococci, were reared continuously under unsuitable condition and fed on the malnutritional mulberry leaves. In such a case, many larvae tested were attacked with a disease of the intestinal flacherie, in which the multiplication of the administrated bacteria with other bacteria was observed in their intestine. Accordingly, intestinal flacherie in the silkworm larvae seemed to have been occurred by multipling the various bacteria in digestive organ, when the larvae had such a delicate condition as to lower the ASP activity of digestive fluid. In the digestive fluid, the alkaline-tolerant streptococci were considered to be primary invaders, and to induce the acid production due to the bacterial multiplication. Secondary, the growth of invaders of various bacteria was induced by lowering the pH of digestive fluid. Therefore, ASP is considered to be a kind of “Defensive Protein” occurring in the digestive fluid.

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In order to clarify the effects of the light and temperature conditions on the food value, the hydroperoxide value in the artificial diets which were exposured to various lights and elevated temperatures and the body weight of silkworms larvae feeding on such diets were measured.
Exposure of the artificial diets to various lights and high temperatures resulted in the production of hydroperoxide lipids. The dietary hydroperoxide values increased in proportion to the intensity and period of illumination and to the increase of the temperature applied. When the silkworm larvae were fed on such diets including hydroperoxide at a high level, the rates of growth and development were reduced.

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A method of the computing the parameters of the nonbroken filament length distribution has been described to obtain one of the informations to predict the evenness of the size of raw silk. The parameters of the distribution which are given as a mixture of the normal and the exponential distribution were examined. To compute the parameters separately, it has been employed the maximum likelihood estimation using the conjugate gradient method. The values of each parameter computed have reasonable informations to estimate the evenness of the size of raw silk.

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The present paper deals with the effects of temperature of incubation stage and light conditions throughout the larval stages on the voltinism of the silkworms (of six races) reared on artificial diet and mulberry leaves, respectively. The results obtained were as follows; (1) The voltinism of silkworms reared on artificial diet was more sensitive to environmental conditions than that of silkworms reared on mulberry leaves. (2) The voltinism of silkworm on artificial diet was strongly affected by the temperature of incubation stage and the light conditions of larval stages. On the other hand, the voltinism of silkworm reared on mulberry leaves was mainly affected by the temperature of incubation stage, but the effect of the light conditions of larval stages seemed little, if any. (3) The effects of food, temperature of incubation stage and light conditions of larval stages on the voltinism of silkworms varied among the silkworm races. In the six races employed, the voltinism of two Chinese races (C. 140 and BC 9) was strongly affected by the food and environmental conditions.

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The suboesophageal ganglion of the silkworm, Bombyx mori, is conceived to secrete two different hormones; diapause hormone (DH) for the silkworm and melanization and reddish coloration hormone (MRCH) for the common armyworm, Leucania separata. Whether or not these hormonal activities are derived from the same chemical entity was determined by comparing the activities of each hormone recovered from the sequential steps of purifications. By the solvent extraction of silkmoth heads, DH-A and MRCH were effectively partitioned into the same fraction. These two hormones behaved similarly on the column chromatographies with Sephadex LH-60, the first Merckogel OR 6000 and DEAE-Sepharose CL-6B. However, DH-A was clearly separated from MRCH in the subsequent purification steps such as the second Merckogel column chromatography or isoelectric forcusirig: As for another kind of DH, DH-B (the smaller in molecular size) was quite different from MRCH as well as DH-A in extractability and chromatographic behaviors. The highly purified sample of MRCH exhibited linear dose-response relationship in cuticular melanization of common armyworms.
The hormonal activities of DH-A and MRCH dropped down by the proteolytic digestions with trypsin, α-chymotrypsin or pronase P and, also by some physical or chemical, treatments. Interesting selective decrement of the two activities occurred only on MRCH by alkaline treatment with 0.1N NaOH and dansylation with DH-A activity unchanged.
Thus, it is concluded that MRCH is a peptidal hormone, whose chemical properties and structure (s) are not identical but is likely to be similar to those of DB-A.

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The increase of detection sensitivity by autoclaving in preparation of specimens, in case of analyzing methacrylamide (MAA) grafted silk fibers by infra-red spectroscopy (KBr disk method), was investigated. Results were as follows;
(1) Silk-fibers treated with MAA gives maximum peak at 1205cm^-1 absorption band which shows the characteristics of Poly-MAA in an infra-red spectroscopy by KBr disk method grind down the material in an agate mortar for 20 minutes. In case of over 40% grafting rate, the absorption band of 1205cm^-1 is evident and effctive for the detection of polymers used in treatment.
(2) By autoclaving at 180°C for 40 minutes, MAA grafted silk have a peak at 3450cm^-1 absorption band which shows N-H stretching derived from thermal decomposition of Poly-MAA in case of above 3% treatment. When the grafting rate is increased the absorption curve of infra-red spectrum falls down deeper. The peak shifts from at 1205cm^-1 to 1220cm^-1 on absorption spectrum and the roughly quantitative analysis of grafted silk fibers is possible depending on the change of absorption spectrum.
(3) Each Styrene, MMA, HEMA and MAA which are grafted to silk fibers even in low rate, can be detected and distingushed by autoclaving of materials.

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The structure of the silk sericin taken off from the liquid silk obtained by casting the liquid silk at different temperatures was studied by means of differential scanning calorimetry (DSC), density and X-ray diffraction. Thermal decomposition temperature of silk sericin cast above 0°C was ca. 250°C, while the specimen obtained by casting the liquid silk below 0°C showed two peaks in the decomposition temperature, namely ca. 220°C and 260°C. Density and endothermic amount of the specimen obtained by casting below 0°C increased. When the casting temperature decreased, the degree of crystallinity of the silk sericin reversely increased, but the crystal structure remained unchanged

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For the purpose of investigating a role of the corpus allatum on imaginal differentiation in Bombyx mori, effect of allatectomy before extirpation of the brain on the duration of subsequent pupal deveropment was examined. By extirpating the brain of Bombyx mori immediately after pupation which had been allatectomized at a known stage before pupation, dauer pupae were induced in the normal races of Bombyx mori. They did not show any sign of imaginal differentiation in 60 days at 25°C. The appearance rate of dauer pupa in the male was higher than in the female in these experiments. In such a limited strain as dauer pupae were induced by only extirpating the brain, the allatectomy was effective on increase of appearance rate of dauer pupa. It was suggested that induction of dauer pupa was related not only to the released stage of brain hormone (PTTH) via the corpus allatum, but also to the transporting stage of PTTH from neurosecretory cells to the corpus allatum.

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The terminal sugar composition of the haemolymph glycopeptides and titre of the bound sugar in haemolymph were determined to make clear the function of α-mannosidase in the haemolymph of the silkworm, Bombyx mori at metamorphosis. Glycopeptide was isolated by gel-filtration on a Sephadex G-25 column from a pronase-digest of the haemolymph proteins. Reducing sugar was released from the purified glycopeptide only by digestion with α-mannosidase, but β-galactosidase and β-N-acetylglucosaminidase had no effects. Thus, the terminal sugar is shown to be mannose. But, Bombyx α-mannosidase did not hydrolysis this glycopeptide. The amount of the sugar bound with haemolymph proteins changed drastically during metamorphosis. However, it does not correspond to the fluctuation of α-mannosidase activity in the haemolymph as reported previously (KIMURA, 1981). The alternative view of the role of silkworm α-mannosidase contrary to the situation of the mammalian enzyme was discussed.

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