• Journal of Sericultural and Entomological Science
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• v.51 no.1
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• pp.41-47
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• 2013

In this study, silkgland powder of silkworm were investigated to see possibility for cosmetic powder materials. To test possibility as a baby powder cosmetics, total content rate of amino acids, DPPH free radical scavenging assay, MTT assay, and clinical trial were done. According to the result of the analysis of the amino acids of silkgland powder, serin (26.77%) content was the highest and asparatic acid (15.47%), and glycine (9.62%) were followed. DPPH free radical scavenging activity of silkgland powder was lower than vitamin C by 82.3% and 97%, respectively, which is relatively good. And the moisture and elasticity effect were increased in silkgland powder compared to control cosmetics by 210% and 185%, relatively. Thus, these results suggest that silkgland powder of silkworm may have beneficial properties as a material for cosmeceuticals.

• Journal of Sericultural and Entomological Science
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• v.43 no.2
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• pp.77-82
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• 2001

This study was investigated to know the effects of diflubenzuron(DFB) on the larval silkgland development of the silk-worm, Bombyx mori (L.). It has been known as a prohibitor of chitin synthesis mostly on the species of the Order Lepidoptera. In this work, the effects of the DFB concentrations (2.5$\times$10$\^$-1/,2.5$\times$10$\^$-2/, and 2.5$\times$10$\^$-3/$\mu\textrm{g}$/$\mu$l on the various larval stages, were investigated in terms on the silkgland. The macro- and microstructure of cell membrane of silkgland, and the differences of silkgland weight and water contents treated by DFB are also surveyed. As the tesults, the silkgland weight depended sensitively on not the DFB concentration but the DFB treatment period. The longer DFB treatment period, the lighter dried silkgland weight and the heavier water content of the silkgland. White opaque(WO) emerged in the middle silkgland of DFB treated larva. From the scanning election microscope observation, the cell membrane of silkgland of DFB treated larva was distinctly more compact compared to that of control. The WO was evidently resulted from the obstacles of normal transformation of silk protein through the cell membrane of middle silkgland.

• Journal of Sericultural and Entomological Science
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• v.22 no.1
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• pp.26-45
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• 1980

Silk protein is synthesized in the silkgland of silkworm, Bombyx mori L. It is evident that silk productivity is one of the high heritable characters from the genetical aspects. It is also changed with the environmental circumstances. With this regard, this paper dealt with the varietal patterns of silkgland development and the factors concerning to the silk productivity of silkgland of silkworm by the synthesis of nucleic acids, profiles of amino acids and histological basis, using the eight parent silkworm varieties and their F$_1$ hybrids. 1. The weight of silkgland per larva increased proportionally in the F$_1$ hybrids which were crossed between longer silk yielding varieties. The silk content to the weight of the silkgland was higher in the longer silk yielding varieties than that in the shorter silk yielding varieties. 2. It was observed that the morphological changes of nuclei took place in the posterior silkgland cells with the larval development of the 5th instar. In varietal aspect, Jam 107 and Jam 108, longer silk yielding varieties, showed more branches in nuclei than the $N_2$ and $C_{60}$ which were shorter yielding ones. 3. It was observed that there was a high correlation between RNA content per unit weight of silkgland on the 6th day stage of 5th instar and silk productivity both in the parents and their F$_1$ hybrids. 4. RNA and DNA synthesis brought about thirty percent increase in the posterior silkgland of the longer silk yielding varieties during the 2nd day to the 4th day stages of the 5th instar, when compared with those in the posterior silkgland of the shorter silk yielding varieties. 5. RNA/DNA ratio in the posterior silkgland on the 2nd day and 4th day stages of the 5th instar was more increased in the longer silk yielding varieties than the shorter silk yielding varieties. 6. It was shown that DNA content for the longer silk yielding varieties came to be 374$\mu\textrm{g}$ per larva in the posterior division of silkgland on the 4th day stage of 5th instar, whereas it was 199$\mu\textrm{g}$ per larva for the shorter silk yielding varieties. 7 There was 34.8％ Alanine, 22.8％ Glycine, 9.1％ Serine and 7.3％ Tyrosine in the posterior division of silkgland as major amino acids. It is noticed that there was a little differences between the amino acids composition of posterior silkgland and silk fibroin. 8. There was some differences in the amino acids composition of posterior silkgland between pure lines and their hybrids. Glycine, Serine and acidic amino acids, essential to silk formation, seemed to be increased in the F$_1$ hybrids, whereas other amino acids such as Valine, Iso-leucine, Leucine, Lysine. Phenylalanine, Histidine and Arginine were reduced. 9. The content of Glycine, Alanine and Serine in the posterior division of silkgland was elevated in the longer silk yielding varieties than the others. Consequently. these three amino acids in the posterior silkgland seemed to be related to the silk yielding ability in the longer silk yielding varieties.s.

• Journal of Sericultural and Entomological Science
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• v.39 no.2
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• pp.140-145
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• 1997

Silkworm fed on mulgerry leaves with 1000 times diluted Insegar(main component : Fenoxycarb, ethyl-2-(4-phenoxyphenoxy)ethylcarbmate) and its effects was investigated on increase of the 5th larval silkgland weight and silk quality. The oral application of fenoxycarb showed increase of the silkgland weight. The whole period of the silkgland weight falls on the 2nd instar treatment by 13%, the 3rd day of the 4th instar by 111%(3100 mg) and the whole period of the 5th instar treatment rather decreased it by 66%(497 mg), as compared to 1470mg of the control. Female and male both increased 15%(1779mg) and 12%(1554mg) of the silkgland weight with the 2nd instar treatment, as compared to 1548mg and 1391mg in control, respectively. 118%(3368mg) and 104%(2832mg) of increase in the silkgland weight were also showed with the 3rd day of the 4th instar treatment but 70%(463mg) and 61%(539mg) of decrease were shown with the 5th instar treatment. The maximum weight of the middle silkgland weight increased by 6%(1248mg) and 127%(2673mg) with the 2nd instar and with the 3rd day of the 4th instar, respectively but 67%(393mg) of decrease took place, as compared to 1175mg of the control. The maximum increase of the posterior silkgland weight with whole peried of the 2nd instar treatment increased 12%(419mg) and 75%(656mg) and 64%(135mg) of decrease was shown, as compared to 374mg of the control. The oral application of Insegar at the 2nd instar increased 26 m of cocoon length, 4.0 cg of the cocoon filament weight and 0.21d of the silk denier, as compared to 1147 m of the cocoon length, 38 cg of the cocoon filament, 2.99d of the silk denier, weight of cocoon filament and silk denier, respectively but denier variance narrowed to 0.33d, as compared to that of the control.

• Journal of Sericultural and Entomological Science
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• v.53 no.1
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• pp.38-43
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• 2015

To increase the income of sericultural farms and expand sericulture industry, new high value-added products of sericulture which are beyond current products like 5th instar 3 day dried silkworm, male pupa and silkworm dongchunghacho are needed. For this sericulture product diversification, it is in desperate need of the edible processing method after 5th instar 4 day silkworm that silkgland formation is rapidly in progress during the larva periods. So far it was hard to eat because of silkgland formation in their body. So we try to boil and steam frozen-, dried-, and living-silkworm to develop low-cost edible processing methods for farmers. As the result, the silkgland of frozen and dried silkworm was not degenerated, so silkgland in their body was not edible. But in the case of living silkworm, the silkgland of mature silkworm was degenerated by boil and steam treatment, so the body and silkgland of silkworm were not only edible but also tasted good. Then the dried silkworm was easily powdered and there was no problem when it was eaten. This source technology can be widely used in the general food industry, health functional food cosmetics, pet food and so on, so it is predictable that this will contribute to increase the income of sericulture farms and expand sericultural industry.

• Journal of Sericultural and Entomological Science
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• v.29 no.2
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• pp.31-37
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• 1987

Mulberry leaf sprayed on at the various concentrations of cadmium (Cd) was fed on the just molted fifth instar through the 6th day of the fifth instar and content of cadmium and zinc in the feces, organs and tissues involved were analyzed by spectrophotometer. Along with the effect of those heavy metals on development of the relevant organs and tissues sexwise. 1. The residual content of cadmium on mulberry leaf was about 50% of the total cadmium and the weight of feces disposed from the cadmium fed larvae was less than the control. There was distinctive differences in female-wise disposal of feces between cadmium treatment and control ; cadmium treatment female larvae disposed less feces than female of control. 2. Fourteen percent of the total dry weight of the anterior plus the middle silkgland and of the posterior silkgland in cadmium 100ppm treatment was decreased in female but only 9% of the anterior plus middle silkgland in male was made, showing no decrease the weight of the posterior silkgland in male. 3. Decrease of the dry weight of the silkgland, fat body and hindgut was made in cadmium 100ppm treatment and contrarily the weight of midgut and malphihian tube were increased. The total larval weight of the female and male were decreasd in cadmium 100ppm treatment and the decreasing ratio was higher in famale. 4. There wasa no detection of cadmium in all of the organs and tissues of the control and in those of the cadmium treatment the high residual content was in order of the midgut, hindgut, malphighian tube and head. A slight accumulation of cadmium was shown in fat body and silkgland. 5. Cadmium accumulation in the midgut was higher than in female but in the fat body, malphighian tube, trachea and integument was contrarily high in the female than male. 6. The total zinc content of the larvae was below 60ppm in the control and 80ppm in cadmium 100ppm treantment. The increase of zinc content in cadmium treatment was made on silkgland, malphigian tube and midgut but contrarily the decrease of zinc content in fat body was resulted. 7. In cadmium treatment, much more cadmium accumulation took place in the female and zinc accumulation was made much more in the male.

• International Journal of Industrial Entomology and Biomaterials
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• v.10 no.2
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• pp.107-117
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• 2005

Oral supplementation of minerals mixture of potassium bromide and nickel sulphate on $CSR_2,\;CSR_4\;and\;CSR_2{\times}CSR_4$ crossbreed races with different concentrations (70, 110 and $160\;{\mu}g/ml$) were fed to the fifth instar larvae. Two of the four normal feeds per day was substituted with treated leaves fed to silkworm at fifth instar larvae. The controls were fed with the leaves sprayed with distilled water and normal leaves. The $CSR_4$ race treated larvae showed a significant increase in silkgland weight, cocooning percentage, female cocoon weight, male cocoon weight, male cocoon shell weight, male cocoon shell ratio, filament length, filament weight, denier, fecundity, number of eggs per ovariole and length of the ovariole when compared with those of the corresponding parameters of the carrier control, whereas in $CSR_2\;and\;CSR_2{\times}CSR_4$ crossbreed races showed a significant increase in larva1 weight and other parameters similar to that of $CSR_4$ race. The results suggested that the silkgland showed good response to minerals mixture of potassium bromide and nickel sulphate only in $CSR_4$ race when compared with those of other two races of the silkworm, B. mori.

• Journal of Life Science
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• v.10 no.2
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• pp.188-195
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• 2000

In order to understand molecular events during silk synthesis and provide genetic resources for molecular breeding, we had analyzed the cDNA library constructed from the posterior silkgland of Antheraea yamamai and partially sequenced 276 randomly selected genes from the cDNA library. Database comparisons of the expressed sequence tags (ESTs) revealed that 26 non-redundant clones showed a high similarity with previously identified genes. Among them, 17 clones exhibited a homology with previously identified insect genes and 9 clones were identical to genes that were previously identified from other organisms. A functional categorization showed that silk synthesis-defense- or stress-related genes, as well as genes involved in the metabolic pathways and in the transcriptional or translational apparatus are represented. In this report, the clone (AY479) which had high similarity with fibroin from A. pernyi was particularly analyzed in detail. The AY479 clone was carboxyl terminal region of fibroin. The 472 bp cDNA has 123 amino acids that shared 85% homology with the fibroin from A. pernyi and its deduced peptide had unique feature, that is, sites of alanine rich residues.

• Journal of Sericultural and Entomological Science
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• v.21 no.1
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• pp.21-28
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• 1979

The Electrophoretic separation in agarose gel on the esterase and acid phosphatase of blood, midgut and silk gland was carried out with 2 original variginal varieties and 7 F$_1$ hybrids. 1. The midgut of larvae fed on mulberry leaves showed one or two more esterase bands than that of larvae fed on artificial diet. 2. The midgut of C 15 larvae being excellently respondent to artificial diet showed one or two more esterase bands than that of larvae being bad respondent to artificial diet. 3. Electrophoretic separation of esterase bands appeared to be greatly different among newly hatched larvae, 1st and 2nd install larvae of F$_1$hybrids. However the difference among the silkworm varieties was not recognized. 4. According to the change in rearing temperature, the number of the active band of midgut esterase was varied. At the temperature of 28$^{\circ}C$ 5 active esterase bands were found. At temperature of 35$^{\circ}C$ 4 bands were noted at 3rd install and 6 or 7 bands at 4th instar. 5. No similar esterase bands conld be found among midgut, blood and silkgland. There are five esterase bands in the midgut, one in blood and three in silkgland. 6. There was rather small difference in acid phosphatase types of midgut and blood according to varieties and rearing temperature. No active band was shown in silkgland. In midgut, there was one acid phosphatase band at 3rd install, two at 4th instar and three at 5th instar. In blood, One active band at 3rd or 4th instar and three bands at 5th inatar were detected.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2000.05a
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• pp.103-103
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• 2000