• International Journal of Industrial Entomology and Biomaterials
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• v.23 no.1
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• pp.115-122
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• 2011

The effect of dietary feeding of silk fibroin/sericinmixtureson the antioxidative status and glucose metabolism in high fat-fed mice was investigated. The mice weregiven experimental diets for 6 weeks: normal control (NC),high fat (HF) andhigh fat supplemented with F100 (pure fibroin, HF-F100), F81 (81:19 fibroin-sericin, w/w, HF-F81) or F50 (50:50 fibroin-sericin, w/w, HF-F50). The silk protein-fed mice showed decreased lipid peroxidation, enhancedantioxidant enzymesactivities and lower blood glucose level relative to HF group. The HF-F50 animals exhibited significantly lower insulin level, higher glycogen concentration, enhanced hepatic glucokinaseactivity and reduced glucose-6-phosphate and phosphoenolpyruvatecarboxynaseactivities than the HF ones. The $in$ $vivo$ antioxidant activity and hypoglycemic action tended to increase with increased amount of sericin and decreased fibroin content in the diet. These findings demonstrate that silk protein, particularly sericin, may be beneficial in suppressing high fat diet-induced hyperglycemiaand oxidative stress.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.04a
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• pp.56-56
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• 2003

Using gel filtration chromatography (GFC), pure separation of high molecular silk fibroin was obtained and silk fibroin microsphere particles (SFMP) could be simply made by spray dryer method. Also, some of its physicochemical properties and morphology were investigated. The average molecular weight (Mw) of pure silk fibroin protein dissolved in calcium chloride is about 61, 500 g/mol as measured by gel permeation chromatography(GPC). (omitted)

• International Journal of Industrial Entomology and Biomaterials
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• v.35 no.1
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• pp.7-13
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• 2017

In this study, changes in gene expression after administration of silk fibroin fragments ($size{\approx}30kDa$) were evaluated in MG63 cells using a cDNA microarray assay. In addition, the level of alkaline phosphatase (ALP) activity and cellular proliferation in the group administered moderately sized silk fibroin fragments ($size{\approx}30kDa$) (MSF) were compared to those in the group administered smaller silk fibroin fragments (size < 1 kDa) (SSF). The results of the cDNA microarray assay show increased expression of genes that are related to the cell cycle and inflammation. ALP, bone morphogenetic protein-7, bone morphogenetic protein receptor type IA, and runt-related transcription factor 2 exhibited significantly lower expression compared to control cells (fold ratio < 0.5). Relative ALP activity of the $100{\mu}g/mL$ MSF group was significantly lower than that of the SSF group (P < 0.05). Thus, the MSF group showed increased expression of genes associated with cellular proliferation and inflammation but decreased expression of genes associated with osteogenesis.

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.1
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• pp.105-112
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• 2023

Oxidative stress in skin cells can induce the formation of reactive oxygen species (ROS), which are critical for pathogenic processes such as immunosuppression, inflammation, and skin aging. In this study, we confirmed improvements from gamma-irradiated silk sericin (I-sericin) and gamma-irradiated silk fibroin (I-fibroin) to skin cells damaged by oxidative stress. We found that I-sericin and I-fibroin effectively attenuated oxidative stress-induced ROS generation and decreased oxidative stress-induced inflammatory factors COX-2, iNOS, tumor necrosis factor-α, and interleukin-1β compared to the use of non-irradiated sericin or fibroin. I-sericin and Ifibroin effects were balanced by competition with skin regenerative protein factors reacting to oxidative stress. Taken together, our results indicated that, compared to non-irradiated sericin or fibroin, I-sericin, and I-fibroin had anti-oxidation and antiinflammation activity and protective effects against skin cell damage from oxidative stress. Therefore, gamma-irradiation may be useful in the development of cosmetics to maintain skin health.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.1
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• pp.7-13
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• 2001

Enzymatic hydrolysis of different forms of silk fibroin (soluble, gel and insoluble forms) by industrial and commercial enzyme preparations to obtain aqueous and powdered silk fibroin in relatively mild conditions was investigated. A mono-enzymatic hydrolysate systems were tested for hydrolysis of water-soluble form of fibroin as most productive form of protein substrate. Insoluble forms of substrate usually were hydrolyzed less effective. In some cases from soluble fibroin substrate gel was formed during hydrolysis process. This hindered intermixing and decreased rates of hydrolysis. Insoluble sediments were formed in enzymatic hydrolysates in other cases. These sediments and also sediment after chemical hydrolysis were purified and tested on amino acids content for comparison. Sediments formation in these conditions are considered as pure tyrosine isolation method. Obtained hydrolysates were characterized by gel-chromatography analysis and other standard biochemical methods. Possibility of application of enzymatic hydrolysis for preparation of silk fibroin hydrolysates is discussed.

• International Journal of Industrial Entomology and Biomaterials
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• v.34 no.1
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• pp.11-15
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• 2017

We constructed the fibroin H-chain expression system to produce enhanced cyan fluorescent proteins (ECFP) in transgenic silkworm cocoon. Fluorescent cocoon could be made by fusing ECFP cDNA to the heavy chain gene and injecting it into a silkworm. The ECFP fusion protein, each with N- and C-terminal sequences of the fibroin H-chain, was designed to be secreted into the lumen of the posterior silk glands. The expression of the ECFP/H-chain fusion gene was regulated by the fibroin H-chain promoter. The use of the 3xP3-driven EGFP cDNA as a marker allowed us to rapidly distinguish transgenic silkworms. The EGFP fluorescence became visible in the ocelli and in the central and peripheral nervous system on the seventh day of embryonic development. A mixture of the donor and helper vector was micro-injected into 1,020 Kumokjam, bivoltin silkworm eggs. We obtained 6 broods. The cocoon was displayed strong blue fluorescence, proving that the fusion protein was present in the cocoon. Accordingly, we suggest that the ECFP fluorescence silk will enable the production of novel biomaterial based on the transgenic silk.

• Journal of Sericultural and Entomological Science
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• v.49 no.2
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• pp.74-76
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• 2007

Antheraea yamamai silk fibroin powder was prepared by treatment with HCl. Amino acid contents of the prepared Antheraea yamamai fibroin hydrolysates were composed of Gly, Ala, Glu, and so on. Biological activities of Antheraea yamamai silk fiborin powder were examined. It is showed about 75% of antioxidation activity compared to the reference ascorbic acid. And it lowered blood glucose level down from 550 mg/dl to 300 mg/dl by serving with wild silk protein.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.1
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• pp.1-6
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• 2001

Silk protein has been investigated by many researchers to apply to biomedical field. We reviewed biomedical applications of silk protein such as matrix of wound dressing and drug delivery system. Since silk fibroin/ poly (ethylene glycol) (PEG) semi-interpenetrating polymer networks showed good mechanical properties and wound healing phenomena, it can be used as wound dressing materials. Sericin nanoparticles pre- pared by conjugation with PEG and silk protein/ poloxamer mixture gel are expected to become a deliv- ery as matrix for hydrophobic drug.

• Journal of Sericultural and Entomological Science
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• v.50 no.1
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• pp.15-19
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• 2012

A number of researcher have studied biomaterials for cartilage regeneration and are now proceeding. Silk protein was attempted for use as biomedical materials by many researchers because it is natural polymer with biocompatibility and excellent mechanical strength. In this study, we want to know a possibility of silk protein on the cartilage regeneration. We isolated chondrocytes from nasal cartilage and confirmed optimal culture condition of the cells. To observe the effects of silk fibroin on chondrogenesis, we added silk fibroin solutions to the culture medium of chondrocyte and detected gene expression levels related chondrogenesis such as col2, col10. The chondrocytes showed optimal growth when they were cultured in DMEM medium supplemented with 10% FBS 100 ${\cdot}{\ddot{I}}$M ascorbic acid. The levels of col2 gene expression were increased in non-autoclaved silk fibroin, but decreased in autoclaved one. Also the gene expression levels of col10 were increased in silk fibroin, particulary at 3D culture. Based on the results of this study, we had seen the possibility of silk fibroin for cartilage regeneration. In future studies, we should know more clearly the relationship between cartilage regeneration and the silk protein.

• Journal of Applied Biological Chemistry
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• v.54 no.3
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• pp.166-170
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• 2011

Silk fibroin, a natural protein produced by silkworm, is a good biomaterial which has biodegradability and biocompatibility. To ascertain the effects of silk fibroin on cell growth, silk fibroin films were prepared using silk fibroin aqueous solutions of various concentrations. We investigated the attachment, proliferation, morphology of the cells and the expression levels of genes related to cell attachment and growth on the silk fibroin films. When the cells were cultured on the 0.1 and 1% silk fibroin film, the cell adhesion ability was very excellent. Particularly, overall cell growth on the 1% silk fibroin film was definitely superior to the others. Also, expression levels of genes related cell growth were increased on the 0.1 and 1% silk fibroin film. These results suggest silk as a material for medical applications.