• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.5
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• pp.554-562
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• 2007

Ceramide rich intercellular lipid lamellae are thought to be particularly important in maintaining the structural integrity of epidermal barrier. Ceramide is synthesized de novo by serine palmitoyltransferase (SPT) phospholipid intermediates, serine and palmitic acid persist within the stratum corneum. The ceramide which is synthesized is degraded with fatty acid and sphingosine by degradative enzyme ceramidase. The depletion of ceramide in stratum corneum was reported in the atopic dermatitis. As an effort to search for the dietary source for improving the level of ceramide in epidermis, the dietary effects of various-typed silk protein were compared. Seventy male NC/Nga mice, an animal model of atopic dermatitis, were divided into seven groups: group CA as an atopic control with control diet, group S: 1% crude sericin diet, group F: 1% crude fibroin diet, group PS : peptide pattern of sericin(Mw 5000), group PF: peptide pattern of fibroin (Mw 1500), group AS: manufactured the same as amino acid profile of sericin and group AF: manufactured the same as amino acid profile of fibroin. Ten male BALB/c mice were served as group C (control group) control diet. All mice were fed on diet and water ad libitum for 10 weeks. Dry skin condition was established in group CA as ceramide content was decreased. Despite a marked decrease of mRNA and prorein expression of SPT, enzyme do novo synthesis, ceramide content of group S was dramatically increased by inhibiting the mRNA and protein expression of degradative enzyme ceramidase. However, dietary supplementation of crude silk fibroin protein (group F) and in other groups that were supplemented with either amino acid or peptide type of sericin or fibroin did not increase the level of ceramide. Together, our data demonstrate that dietary supplementation of crude sericin is more effective at improving ceramide level in epidemis of NC/Nga mice.

• Applied Microscopy
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• v.12 no.2
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• pp.35-44
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• 1982

The fat bodies of cabbage worm (Pieris rapae) and silk worm (Bomyx mori) during metamorphosis was comparatively studied by electron microscope. 1. Cell oranelles: Golgi apparatus were not observed in both species. It is observed that RER of cabbage worms initiate to degenerate in prepupa stage with complete degeneration at adult stage, while that of silk worms shows similar degenerative pattern. However, mitochondria of cabbage worms are transformed into autophagic vacuole from prepupa stage until adult stage whereas those of silk worm shows a decrease in number in prepupa stage but maintains a certain level until adult stage. 2. Storage substance in cell: Lipid droplets in cabbage worms were observed to increase in numbers during larval stage but afterward decrease in number with an enlargement in size. However immediately after their pupal stage, they almost disappear. On the contrary lipid droplets in silk worms show rather increase in number until adult stage. Protein storage granules in bothspecies were arised from autophagic vacuoles(lysosome) . Fat cells of cabbage worm in adult stage turn out to be residual bodies which last until final stage, but those of silk worm rapidly decrease. Glycogen particles in both species reach maximum at last larval instar and thee gradually decrease thereafter. 3. Fat body sheath: The average width of fat body sheath was measured to be $0.2{\mu}m$ and $0.6{\mu}m$ and surface of fat cells adjacent to fat body sheath in silk worm is heavily infolded.

• 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.

• Membrane Journal
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• v.17 no.4
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• pp.375-380
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• 2007

To recover sericin protein from by-product in silk production process, a polyethersulfone hollow fiber ultra-filtration membrane module was used. The soap in the degummed solution was precipitated by calcium chloride. The influence of membrane module of submerged and external type on membrane fouling was investigated. The effect of soap and protein on the membrane fouling in the external type membrane module was also studied. The removal of soap resulted in decreasing the membrane fouling. It was shown that the protein and the membrane were affected by the soap.

• Journal of Sericultural and Entomological Science
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• v.43 no.2
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• pp.109-115
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• 2001

Silk sericin protein was extracted by treatment with enzyme or NaOH solution from raw silk and culled-cocoon shell. The extracted sericin was characterized and examined the functional properties as well as subjective properties for its use as a soap and a body cleaner. The optimum extraction conditions on specimen are NaOH (0.02 wt.%) or enzyme, Flavourzyme 3% under N2 gas. Molecular weights of sericin was decreased by treatment with enzyme, Actinase, from 10,000-30,000 to 2,700-4,200. Sericin showed important bioactive properties, for instance, lowering effect on blood glucose and alcohol. Subjective test of sericin soap and body cleaner showed superior in washability, foamability, and skin hydration, etc., to commercial soap and body cleaner. Therefore, it is thought that silk sericin can be expected as the source of bioactive and skin-compatible materials.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2005.04a
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• pp.65-79
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• 2005

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2010.03a
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• pp.64-65
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• 2010

• Journal of Life Science
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• v.10 no.5
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• pp.511-518
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• 2000

This study was designed to investigate the effects of silk fibroin powder (SFP : Mw 500) on oxidative stress and membrane fluidity in brain membranes of rats. Sprague-Dawley (SD) male rats (160$\pm$10 g) were fed basic diet (control group), and experimental diets (SFP-2.5 and SFP-5.0 groups) added 2.5 and 5.0 g/kg BW/day for 6 weeks. Cholesterol level was significantly decreased about 8.0% in brain microsomes of SFP-5.0 group only compared with control group. Membrane fluidities were significantly increased (12.9% and 15.2%, respectively) in brain microsomes of SFP-2.5 and SFP-5.0 groups, but significant difference between in brain mitochondria of these two groups could be not obtained. Basal oxygen radicals (BOR) in brain mitochondria and microsomes were significantly ingibited (10.4%, and 24.0%, 7.9% and 14.9%, respectively) by SFP-2.5 and SFP-5.0 groups compared with control group. Induced oxygen radicals (IOR) in brain mitochondria and microsomes were significantly inhibited (11.8% and 14.1%, respectively) by SFP-5.0 groups compared with control group compared with control group. Lipid peroxide (LPO) levels were dose-dependently decreased (12.9% and 21.9%, 13.2% and 22.5%, respectively) in brain mitochondria and microsomes of SFP-2.5 and SFP-5.0 groups compared with control group. Oxidized protein (OP) levels were significantly decreased (15.7% and 17.1%, 16.7% and 15.7%, respectively) in brain mitochondria and microsomes of SFP-2.5 and SFP-2.5 and SFP-5.0 groups compared with control group. These results suggest that administration of SFP may play an effective role in a attenuating a oxidative stress and increasing a membrane fluidity in brain membranes.

• Journal of Sericultural and Entomological Science
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• v.6
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• pp.18-27
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• 1966

This treatise was sat up as a basic study of the artificial diets of silk worm, both nursed and wild, by storing the natural leaves in defarmentizing solution and the results obtained were as followings. 1. Defarmentizer C, a kind of defarmentizer, was developed by the author in order to store any natural diet by soaking them in the solution. 2. The defarmentizer was workable for aerophobic bacteriums, but was not effectable for aerophilic bacteriums or fungus. 3. The defarmentized diet could feed silk worm during winter season. 4. The storing method has found the importance of growthness of the diet leaves and the perfect riped leaves were found as the best condition for the purpose. 5. The perfect riped leaves were softened properly during the soaking to be fed for silk worm. 6. The defarmentizing solution has held almost the same pH value of protein isoelectric point so that the protein extraction be ceased during the soaking process. 7. The utilization of defarmentizer has found an economical value. 5. The analytical results of various wild plant leaves were found to be usable as the artificial diet mixture for general silkworm.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.2
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• pp.95-102
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• 2000

Experiments related to the field of sericulture started in the years 1900, in Korea. The sericultural experimental station in Korea was first organized among agricultural fields in Korea, indicating that sericulture in Korea was regarded as an important field of agriculture. Sericulture has been devoted to a great deal for the improvement of Korean economy during the past 100 years even under the coarse social circumstances caused particularly by the Korean War, However, the traditional Korean sericulture, aimed to produce silk yarn, was weakened, because of several reasons such as diminishment in silk consumption, increased labor charge in Korea, and so on. After this difficulty time, the Korean sericulture was revolutionized by shifting into functional sericulture from 1995, and the Korean sericulture now plays an important role for the improvement of human health. Mulberry tree, silkworm, and silk have a boundless potential to be developed as resources. We expect the know-how obtained through silkworm research would expand to the other insect research too. Thus, an area of entomological industry is hoped to prosper owing to insect research as well as sericulture. Mulberry tree is known to possess many bio-active substances, so it can be utilized as a resource for substitute medicine and a raw material for the functional food. In addition, an invention of genetically engineered mulberry variety, which will produce more bioactive substances, is expected. Silkworm is one of the most extensively studied insect organisms on the genome so far, Thus, silkworm is expected to be an "insect bio-factory", enabling mass-production of useful proteins by transformation, in which useful foreign genes are assimilated into silkworm. Silk can be transformed into several phases, because it possesses useful functional groups, which are sensitive to chemical reaction. Also, because silk fibrin itself is protein, it has a superior applicability as tissue membrane. Due to this usefulness, many researchers are now working on the silk as food, cosmetic, medical resource, and bioengineering resource, and even an expanded application is expected using silk in the future. Until now, the researches on insects were largely focused on the prevention of the damage caused by pest, instead of a beneficial aspect. However, insects are thought to be the fourth natural resource in the world, possessing unlimited potential as world resources in the near future. Therefore, our entomological research effort should be focused on the subject with potential for industrialization. Such subject includes selecting the insect species useful for environmental evaluation, construction of environment-friendly agricultural ecosystem, pollen mediation, pet, and advanced bio-resources.