• Journal of Sericultural and Entomological Science
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• v.18 no.2
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• pp.101-105
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• 1976

The study was carried out to investigate the variations in the fibroin hydrolysis of leading silkworm varieties in Korea, and the relationship between the fibroin hydrolysis of the silkworm varieties with some characteristics and silk morphological property. The results obtained are summarized as follows: 1) The fibroin hydrolyzing ratio of both parent silkworm cocoons was reduced in the F$_1$hybrids. 2) A positive corelation (r=＋0.86) was approved between the mid-parent value and the F$_1$hybrid in the fibroin hydrolysis. 3) It was disclosed that the fibroin hydrolyzing ratio of Jam 103${\times}$Jam 104 was the lowest among the leading silkworm F$_1$hybrids. 4) The fibroin hydrolysis was affected by the silk morphological property, showing a positive corelation between the size of cocoon filament and the fibroin hydrolyzing ratio. 5) It was thought that the determination of the fibroin hydrolyzing ratio was useful as a marker for the selection of its related economical characters in silkworm breeding, because the fibroin hydrolysis of parents silkworm cocoons was heritable in their F$_1$hybrids.

• Journal of Sericultural and Entomological Science
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• v.17 no.2
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• pp.155-160
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• 1975

The study was carried out to investigate the effects of various compositions of artificial diet for silkworms on the cocoon shell fibroin-hydrolyzing with the proteolytic enzyme. The obtained results are summarized as follows： 1. It was found that the fibroin-hydrolyzing ratio of the cocoon shell made by silkworms fed with artificial diets was lower than that of the cocoon shell made by silkworms fed with natural diet (mulberry leaf) 2. The amount of soybean meal in the artificial diet was negatively related to the sericin content of cocoon shell but it scarcely affected on the fibroin-hydrolyzing ratio. 3. The increase of sucrose in the artificial diet reduced the sericin content of cocoon shell but it didn't influence on the fibroin-hydrolyzing ratio. 4. A significant difference between male and female silkworms fed with artificial diets was found in the sericin content of cocoon shell but it was not approved in tile fibroin-hydrolyzing ratio. 5. The artificial diet containing 8 per cent of mulberry leaf powder increased the fbroin-hydrolyzing ratio more than that containing 10 per cent of mulberry leaf powder or that containing 8 per cent of mulberry leaf powder and a little of methionine did. 6. The artificial diet for all instars of silkworms increased the fibroin-hydrolyzing ratio more than the artificial diet for 1st to 3rd instars and natural diet (mulberry leaf) for the rest instars did.

• Journal of Sericultural and Entomological Science
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• v.5
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• pp.53-55
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• 1965

This was the report of Hydroxyproline detection in silk fibroin and the obtained results were as followings. 1. Hydroxyproline was analized 25∼75 p.p.m. in specific species silk fibroin. 2. The amino acid was included more in crossed species silk fibroin than in the original species fibroin. 3. The number of amino acids in silk fibroin increased from 18 to 19 kinds.

• KSBB Journal
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• v.26 no.5
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• pp.422-426
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• 2011

Alginate bead has been supplemented with various polymers to control permeability and to enhance mechanical strength. In this report, fibroin-reinforced alginate hydrogel was prepared, in which spatial localization of fibroin molecules was investigated. Confocal laser scanning microscopy revealed that fibroin molecules formed a fibrous network in the alginate-fibroin beads, which was expected to enhance mechanical strength as same as in many composite materials. Uniaxial compression test showed that fibroin-reinforced alginate beads had increased mechanical strength only after methanol treatment that caused ${\beta}$-sheet formation among fibroin molecules. Simultaneous curing and dialysis of alginate beads were carried out to remove excesscalcium but to retain fibroin in the dialysis chamber, which fabricated beads without internal fibrous fluorescent stains. Fibroin molecules were only found beneath the surface of the beads. The fibroin-diffused shell was further processed to form a thick wall after drying or was mobilizedto the centre of the bead by methanol treatment. Accordingly, the structure analyses provide processing methods of fibroin to form a wall or center clumps, which could be applied to design controlled delivery device.

• International Journal of Industrial Entomology and Biomaterials
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• v.30 no.1
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• pp.1-5
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• 2015

Understanding the interactions between fibroin and sericin is crucial in solving the mechanism of silk spinning. In this study, various commercially available dyes were used to monitor the interface between fibroin and sericin during the gelation of fibroin. The phase separation between fibroin and sericin could be observed by the addition of azo dyes over a certain molecular weight. Furthermore, the addition of the dyes to the sericin layer showed vivid phase separation over addition to the fibroin layer.

• Journal of Biomedical Engineering Research
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• v.43 no.4
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• pp.251-258
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• 2022

Silk fibroin microparticles were fabricated using a phase separation technique between silk fibroin solution and polyvinyl alcohol. We found that the concentration of polyvinyl alcohol determines the size of microparticles. The mean diameter of the silk fibroin microparticles varied from 3.48 ㎛ to 4.05 ㎛. The silk fibroin microparticle size increased as a function of the concentration of PVA in aqueous silk solution. The resulting silk fibroin microparticles have narrow size distribution (i.e. monodisperse) and smooth/spherical surface. Also, we studied the effects of mouse serum, sodium phosphate buffer (PBS), and pH on the stability of the silk fibroin microparticles. Overall, we demonstrated the simple method to fabricate and to control the silk fibroin microparticles that makes our silk microparticles to be usable for a potential drug delivery carrier.

• The Korean Journal of Food And Nutrition
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• v.9 no.4
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• pp.496-499
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• 1996

In order to develop the functional diet food, characteristics of chitosan and silk fibroin composite was designed. Chitosan extracted from a prawn and silk fibroin was prepared from silkworm. The silk fibroin was dissolved rapidly in the 8M LiBr at a temperature of more than 4$0^{\circ}C$. Amino acid composition of fibroin composite revealed the same pattern that of native silk fibroin and regenerated silk fibroin. Predominant amino acid of chitosan-fibroin composite contained glycine, alanine, serine, tyrosine, threonine, and glutamic acid in order. According to the basis on the infrared spectrum, chitosan-silk fibroin composite is not distinguished differents composite ratio of chitosan and silk fibroin.

• Journal of Sericultural and Entomological Science
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• v.37 no.2
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• pp.142-153
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• 1995

This study is undertaken to investigate proper condition and dissolution method of silk fibroin to use it functional material as powder or membrane. Silk fibroin was dissolved with calcium chloride ethanol aqueous solution and hydrochloric acid. When silk fibron was dissolved with calcium chloride ehanol aqueous solution, main chain of silk fibroin was degradaded and molecular conformation was changed. Silk fibroin powder was made from silk fibroin solution. It showed lower thermal decomposition temperature and crystallinity than those of native silk fibroin. And Its molecular conformation was random coil structure. By acid gydrolysis, main chain of silk fibroin was attacked randomly. Silk fibroin powder from hydrolysate showed high crystallinity and thermal decomposition temprature. $\beta$-form molecular conformation was found by IR and X-ray diffraction. Silk fibroin powder form dissolved part with hydrochloric acid showed low thormal decomposition temperature but high crystallinity. During acid hydrolysis, transition of molecular structure of silk fibroin occurred, and it changed to $\alpha$-helix. Silk fibroin film was achieved by casting silk fibroin solution by ehanol solution or saturated vapor treatment, and its molecular conformation changed to $\beta$structure.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.1
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• pp.49-55
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• 2003

We describe the generation of transgenic silkworm that carrying the chimeric fibroin light chain (L-chain) gene. Previously, we have cloned the complete fibroin L-chain gene from the silkworm Baekok-Jam, Bombyx mori, and the complete fibroin gene from the oak silkworm, Antheraea yamamai. The 444 bp repetitive sequence of A. yamamai fibroin gene was inserted into the exon 6 of B. mori fibroin L-chain gene to produce chimeric fibroin L-chain gene. The chimeric fibroin L-chain gene was cloned into the polyhedrin gene site of Autographa californica nuclear polyhedrosis virus (AcNPV) to yield a recombinant baculovirus as a fibroin gene targeting vector, One-day-old fifth instar female silkworm larvae were injected with the recombinant baculovirus and then mated with normal male moths. Genomic DNA from their progenies was extracted and screened for the desired targeting event by using PCR and Southern blot analysis. The analysis showed that the chimeric fibroin gene had intergrated into the L-chain gene on the genome by homologous recombination and was transmitted through generations. The transgenic silkworm carrying the chimeric fibroin gene were approximately 43.2% in $F_2$ generation, and the silkworms synthesized the fusion protein in cocoons layer.

• Journal of Sericultural and Entomological Science
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• v.42 no.1
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• pp.42-47
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• 2000

Structural and thermal characteristics of silk fibroin/poly(2-hydroxyethyl methacrylate)(PHEMA) blend films were investigated using FTIR, X-ray diffractometer, differential scanning calorimeter, thermogravimeter and scanning electron microscope. FTIR spectra showed that the conformation of silk fibroin prepared by dissolving in formic acid was $\beta$-sheet, which did not affected by blending with PHEMA. The X-ray diffraction patterns also showed that individual crystalline structure of silk fibroin and PHEMA was not affected for the blend films. The initial thermal decomposition temperature of silk fibroin/PHEMA blend film tends to be higher than either of silk fkbroin or PHEMA. Thermal stability of both polymers, more notably PHEMA, can be improved by blending two components. As a result of SEM observation, the phases separation for silk fibroin/PHEMA blend films occured regardless of blend ratio ; continuous and dispersed phase were silk fibroin and PHEMA component, respectively.