• Textile Coloration and Finishing
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• v.19 no.1 s.92
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• pp.31-36
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• 2007

There are several factors in the degradation of textiles. The crucial factors in textile weakening are humidity, dust, smoke, sunlight, microorganisms and so on. Especially silk fabrics are more susceptible to microorganisms than other fabrics, because they are mainly consisted of proteins. In this study, we investigated the activities for degrading casein and silk fibers with 2 strains, Bacillus cereus TX1 and Pseudomonas fluorescens TX 2, isolated from domestic museums. They were compared to those of standard control strains, Klebsiella pneumoniae and Staphylococcus aureus, usually used for the antibiotic test of fabrics. The caseinolytic activities of K. pneumoniae and S. aureus were higher than those of isolated strains. But in the cases of silk fiber degrading, B. cereus TX 1 showed the highest activity on both silk 1 and silk 2. Therefore, caseinolytic activities were not coincident with the activity to degrade silk fibers. All strains degraded silk 1(strength retention 100%) better than silk 2(strength retention 50%). It means that bacteria mainly participate in the early stage of degrading silk fabrics, but as time goes by, the importance of bacteria for degrading silk fabrics would decreased. Even though the importance of bacteria may decrease, controlling bacterial activity is necessary to preserve historic silk fabrics.

• International Journal of Industrial Entomology and Biomaterials
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• v.11 no.1
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• pp.13-19
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• 2005

Biotechnological researches in Central Asian Research Institute of Sericulture were developed since 1981 when laboratory of artificial diets for mulberry silk­worm was created. The researches were directed not only to creation of accessible artificial diets (AD) for off-season mass rearing of economical beneficial insect and for industrialization of sericulture but also to obtaining of easy reproducible source of animal proteins, carbohydrates, lipids, enzymes, enzymes inhibitors and other metabolites - bioresource for manufacture of oriental medicine preparations. Space experiments with silkworms became possible with use of AD. These experiments used mulberry silkworm as high effective board test organism with outstanding developmental, reproductive and transgenic properties having impor­tant significance in future of cosmonautics. Introduction to practice of bioprotective and ecologically pure method of drying and sterilizing of green cocoons and by-products of silk manufacture allows to increase efficiency of cocoons reeling technology as well as to preserve nativity of biological active substances in mulberry silkworm pupae that is unachievable by traditional methods of raw material processing. New spheres of application of two important silk proteins - fibroin and sericin in medicine, cosmetics, for bio- and nanotechnology are opening with use of biotechnological approaches. At present the achievements and experience of R & D in these fields are used in creation of modern pests biocontrol agents. Schemes of efficient processing of cocoon raw material, by-products and wastes of sericulture and cocoon processing are devel- Institute of Physiology and Biophysics, Uzbek Academy of Sciences, I, Niyazov street, 700095, Tashkent, Uzbekistan. oped for obtaining of traditional and new consumer products.

• Fibers and Polymers
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• v.2 no.2
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• pp.71-74
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• 2001

Surface characterization of materials has been considered critical in the development of biomaterials, as many unfavorable responses from the body occur at the interface between a material and the body component. The contact angle measurement is one means to characterize the surface properties and to correlate them to the biocompatibility of materials. In this paper, surface characteristics of silk fibroin/S-carboxymethyl kerateine, representative fibrous proteins, were investigated by contact angle measurements of ESCA. The biocompatibility of the blends was evaluated based on minimal interfacial free energy concept, and compared with other potential biomaterials. It was also hypothesized that the enhanced surface polarity of the blends was generated from the conformational transition of proteins. This approach to evaluate the biocompatibility of materials based on surface characteristics may find wide utility in many biomedical applications.

• Journal of Sericultural and Entomological Science
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• v.51 no.1
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• pp.68-72
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• 2013

Fibroin and sericin are natural proteins obtained from cocoon and one of the spotlight materials for medical device. Medical device made of these proteins also has the advantage that this material is biodegradable in to amino acid. In this study, we prepared silk sponges using fibroin, sericin and additives. The characterizations of the silk sponges such as morphology, stability, and blood absorbency were observed. The structural stability of the silk sponge decreased significantly by increasing sericin contents. The effect on the concentrations of ethanol to induce crystallization was observed to be superior to 70% ethanol. Structural stability of silk sponges containing additives was very lower than those not containing additives. The blood absorbency of the silk sponges was found to be excellent, regardless of the composition of sericin and fibroin. The resilient power of these sponges was also very good, in spite of the repeated soaking and drying. Therefore, we expect that the silk sponges can be used medical supplies such as plastic implants and hemostatic cotton.

• Journal of Sericultural and Entomological Science
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• v.46 no.2
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• pp.72-76
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• 2004

We have studied the effect of silk proteins to the cell proliferation of human skin fibroblast cells (CCD-986sk) after injury. Silk proteins were extracted treatment with enzyme or NaOH solution from raw silk and culled-cocoon shell of Bombyx mori, Antheraea yamamai and A. pernyi. The cell proliferation after in vitro injury are increased in treatment by Bombyx mori (BM-1,2), Antheraea yamami (AY-1,2) and A. pernyi (AP-1,2). The silk protein fractions-treated cells exhibited proliferation in a dose dependent between $0.1\;{\mu}g/ml$ and $10\;{\mu}g/ml$. But, the macrophage, RAW 264. 7 cell viability was unaffected by the silk protein fractions by MTT assay. The molecular weights of the silk protein fractions were from 300-600 to 900-1500. These results results that the silk protein fractions may function through skin fibroblast proliferation.

• Journal of Sericultural and Entomological Science
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• v.48 no.1
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• pp.6-10
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• 2006

Recently, B. mori proteins such as silk fibroin and silk sericin have been found to have a water-holding capacity, anti hydrogen peroxide toxicity, antioxidant activity and tyrosinase-inhibitory activity (Yeo 2006, Kurioka 1999 & 2004), implying its potential usefulness of the application for cosmetic and functional food(Yamazaki 1999 & Une 2000). We are tried to application for dietary resources of B. mori silk fibroin and sericin that were prepared to some of different molecular cutting these resources by preparative recycling HPLC system. In our studies with rats have demonstrated that consumption of these silk proteins are being prevents constipation effect and it is maybe enhances intestinal absorption of water and dietary effects. These some of useful results further suggest a usefulness of sericin as dietary resources for health.

• KSBB Journal
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• v.13 no.1
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• pp.114-118
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• 1998

The effects of fibron solubilization conditions on molecular weight distribution of enzymatically-hydrolyzed silk peptides were investigated. The weight-averaged molecular weights of silk proteins prepared by solubilization with calcium chloride, ethylenediamine and sulfuric acid were 41600, 3308, and 1268 dalton, respectively. Silk peptides in the average molecular weight range of 600-1200 dalton were obtained by protease treatment from solubilized silk fibroin. After the acid hydrolysis of silk protein using hydrochloric acid for 24 hr, silk protein was hydrolyzed to peptides whose average molecular weight and free amino acid content were 145 dalton and 80%, respectively. It was possible to control molecular weight distribution of silk peptides by the combination of solubilization and hydrolysis methods. Among the various treatment methods, acid solubilization followed by protease treatment had an advantage of molecular weight control for the peptide production.

• Macromolecular Research
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• v.16 no.6
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• pp.539-543
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• 2008

Many natural proteins self-assemble in complex ways, either to fulfill their biological function or introduce particular properties, such as high strength and toughness. We report the morphological transition in water from a spherical to rod-like shape of Bombyx mori silk fibroin by reducing the pH. Transmission electron microscopy, scanning electron microscopy, and dynamic light scattering were used to characterize the dilute solutions of silk fibroin in an aqueous environment, and provide direct visualization of the transformation of spherical micelles at pH 6.8 to nanofibrils at pH 4.8. This change in morphology occurred as a result of the stretching entropy due to the formation of $\beta$-sheets, which was analyzed using circular dichroism spectroscopy. This study demonstrates the self-assembly of silk fibroin as a function of pH.

• Textile Coloration and Finishing
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• v.14 no.4
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• pp.249-258
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• 2002

Natural silk is formed by two proteins : the crystalline fibroin (inside the silk thread) and amorphous sericin (as a tube outside the thread). The degumming process is used to eliminate the external sericin prior to dyeing ; generally it makes use of soaps at about pH 10. Sericin is the protein constituent that "gums"together the fibroin filaments of cocoon silk. It constitutes about 25% of the weight of the cocoon, is soluble in hot water and "gels" on cooling. The removal of sericin from raw silk, known as degumming, is a simple but important process usually employing hot dilute soap or alkaline solution and occasionally dilute acids or enzymic methods. During degumming, alkali is taken up by the sericin and the free acid from the soap is formed ; this may be deposited on the fiber, reducing the rate of degumming and protecting it from hydrolysis. Alkali is often added to maintain or restore the pH of the baths, but it is rarely used alone, since it leaves the silk rather harsh in handle. If complete sericin removal is required as for printing, sodium carbonate may be added. If the pH of the bath exceeds 11, the fibroin is attacked. Recently, According to the development of electrolysis, we can be obtained the electrolytic reduction water(above pH 11.5) and electrolytic oxidation water (below pH 3). The aim of this work was to study a degumming process using electrolytic water and a possibility of sericin recovery. The new degumming process used electrolytic water operates at $95^\circ{C}$ for 2hr. without any reagents. The wastewater of this process are formed by a solution of sericin in water. This conditions suggest the study of a possible recovery of this protein (sericin) which has an amino acid composition suitable for many used in cosmetics, textile finishing agents, animal feeding, etc. The degumming process using electrolytic water is available to reduce treatment costs and pollute and at the same time to recover sericin.

• Journal of the Korean Chemical Society
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• v.20 no.4
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• pp.299-308
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• 1976

Cerium (Ⅳ) ion-initiated graft copolymerizations of acrylamide and of acrylonitirile to silk fibroins were investigated. When acrylamide was used, the change in ceric ammonium nitrate concentration exhibited a maximum in degree of grafting at 0.01 M. Also observed was that the change in acetic acid content in reaction media gave a maximum in degree of grafting at 7% acetic acid in water. Degree of grafting was increased generally with increase in acrylamide concentration reaction time and reaction temperature. When acrylonitrile monomer was used for grafting,different results were obtained. Addition of nitric acid was more effective in enhancing the degree of grafting than the addition of acetic acid.Generally the grafting of acrylonitrile to silk fibroins was less efficient than the grafting of acrylamide. The portion of grafted silk fibroins insoluble in Lowe's reagent exhibited the IR absorption bands characteristics to both vinyl polymers and silk fibroins, indicating the grafting of vinyl monomers to silk fibroins. To examine the molecular weight of graft vinyl polymer, a sample of grafted silk was hydrolyzed by 10% sodium hydroxide. Viscosity measurements indicated that the molecular weight of the graft polymer was in the range of 105.