• International Journal of Industrial Entomology and Biomaterials
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• 제38권2호
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• pp.51-55
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• 2019

The structure and properties of silk polymers (fibroin and sericin) can be satisfactorily controlled by choosing a suitable silkworm variety and, hence, this parameter (i.e., silkworm variety) has attracted increasing attention. A previous study reported that the crystallinity of white colored silkworm cocoons depends on the silkworm variety. In the present study, sixteen yellow colored silkworm variety cocoons were produced and their molecular conformation and crystallinity were investigated. The conformation of the silkworm cocoons varied with the silkworm variety. Most cocoons exhibited ${\beta}$-sheet conformation, although random coil and ${\beta}$-sheet conformations co-existed in some cocoons (e.g., 21 and D90). The crystallinity of the silkworm cocoons varied with the silkworm variety and the measurement position of the cocoon (i.e., outer surface or inner surface). However, the difference in the crystallinity indices of the outer and inner surfaces comprising the cocoons varied with the silkworm variety, but was <2% for all cocoons, except for MAL.

• International Journal of Industrial Entomology and Biomaterials
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• 제19권2호
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• pp.265-268
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• 2009

Wild silkmoths can be utilised sustainably in the production of silk as an income for resource-poor rural communities. However, attack by parasitoids and predators affect the quality of cocoons and quantity of raw silk produced. A laboratory experiment was undertaken to quantify the effect of parasitoids' (dipteran and hymenopteran) and predators' (ants) exit and ingress holes, respectively, on silk production. The mean number of shells required to produce fifty grams of raw silk was highest with cocoons parasitised by a dipteran and lowest with unattacked cocoons (but with moths already emerged). Degumming loss was highest in parasitised and lowest in unttacked cocoons, but both were not different from cocoons predated by ants. Shell weight was highest in unattacked cocoons, followed by hymenopteran-parasitised and predated cocoons, with the dipteran parasitized ones being the least. Single cocoon weight was greater in hymenopteran-parasitised and predated cocoons than the dipteran-parasitised and unattacked cocoons. Shell ratio or raw silk, floss and yarn weights were higher in unattacked than parasitised and predated cocoons. The total loss in raw silk attributable to attack by parasitoids and predators ranged between 17.4~31.2%. The results offer baseline information for assessment of economic losses in wild silk farming due to parasitoids and predators in the field.

• 한국잠사곤충학회지
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• 제13권1호
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• pp.61-67
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• 1971

본 실험은 이상견이 제사과정에 있어서 사질에 미치는 영향을 구명하기 위해 수행된 바 그 결과를 요약하면 다음과 같다. 1. 견장, 견폭, 견중, 견층중 견층비율은 이상견이 정상견에 비하여 0.83∼4.65%가 떨어진다. 2. 견층의 두께는 20.62∼22.42%가 이상견이 정상견에 비하여 얇다. 3. 견층 sericin의 용해도는 11.75∼30.05％가 이상견이 정상견에 비하여 높다. 4. 견층연감율은 이상견이 정상견보다 6.51∼9.32% 높다. 5. 이상견은 정상견에 비하여 견사장9.43%, 견사량 8.53% 생사량비율 6.72%가 떨어진다 6. 해서율은 이상견이 정상견보다 9.58% 저하하였다. 7. 소절은 이상견이 정상견에 비하여 3점 떨어진다. 8. 대중절은 정상견에 비하여 이상견이 1.5∼3.8배나 많았으므로 대중절성적은 16.3 점이 저하되었는데 이는 특히 split ends가 많은 것에 기인된 것이다. 9. 양견수는 이상견에 있어서 정상견에 비해 1.4∼5.5배가 많고 사조고장의 주요원인이 되는 마디수는 1.9∼3.5 배나 많았다.

• 한국잠사곤충학회지
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• 제18권2호
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• pp.107-110
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• 1976

In silk reeling process the carry-over cocoons must be submerged in the reeling baths filled with reeling water and left until reopening the operation. Under the detention the carry-over cocoons are apt to decay without any antiseptic treatment. Thus an useful antiseptic for the cocoons is urgently needed, and various antseptic agents have been tested for their applicability to the process. However, such an useful agent has not been developed yet. Formalin has been the only chemical used for antisepticizing carry-over cocoons, although it has many defects as the antiseptic for the cocoons. In these circumstances, recently we newly prepared an antiseptic useful for preventing the carryover cocoons from decaying. We named the new antiseptic preparation "Swi-Se-Yo." The Korean term "Swi-Se-Yo" literally means "please take a rest". Through a series of experiments with Swi-Se-Yo we obtained the following results: 1) Swi-Se-Yo, in 0.05% aqueous solution, exerted a good antiseptic effect on the boiled Cocoons submerged in the reeling baths and the effect lasted for 45 hours. The duration of the effect is about two times longer than that of Formalin. 2) The percentage of cocoon reel ability of the carry-over cocoons treated with Swi-Se-Yo was 6% higher than that of Formalin and was equal to that of flowing cold water. 3) The percentage of raw silk yield of the carry-over cocoons treated with Swi-Se-Yo was almost equal to that of Formalin and to that of flowing cold water. 4) The quality of raw silk of the carry-over cocoons treated with Swi-Se-Yo is the same as that of flowing cold water. Besides the above favourable results, Swi-Se-Yo has many advantages as an antiseptic. Chemically it is very stable. Its antimicrobial action is very strong and the spectrum is very broad. It can be available in water-soluble powder and in small bulk. And it is not harmful to human and domestic animals. Considering these profitable properties of Swi-Se-Yo, it will have a good reputation as a carry-over cocoon antiseptic. (The chemical composition and manufacturing method of Swi-Se-Yo will be published in the near future.)

• 한국잠사곤충학회지
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• 제17권1호
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• pp.1-26
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• 1975

These studies were attempted to find out the optimum silk reeling system by use of automatic silk reeling machine to increase raw silk yield and reeling efficiency with various silk reelable cocoons. The obtained results are as follows; 1. The mean silk reelability ratio(X)of the Korean cocoons during the last ten years was 61 per cent, beside 64.7 per cent in autumn cocoon and 57.3 per cent in spring cocoon. However, the ratio variation of autumn cocoons was larger than that of spring cocoons. 2. A positive correlation between cocoon filament breaks during its process and silk reelability levels was shown to be significant. The cocoons of both poor and good reelability evidenced "J" shape distribution on the filament break graph by the order of reeling cocoon end. Many bave breaks were found at the inner shell of the cocoons, or in case of poor reelability cocoons. 3. The morphology of broken cocoon ends during the process was classified into A, B, C, D, E and F types, The occurrence of B type was majority, but that of F type was minority among them. 4. In case of the cocoon cooking, H-type ion-exchanged soft water was better for good reelability cocoons, Na and H-type ion exchanged neutral soft water for those of fair reelability, and alkaline (Na-type) soft water for those of poor reelability, respectively. 5. The modification of cooking water by mixing the above different types of water (50％ Na-type and 50％ H-type passed by standard natural water; 75％ Na-type and 25％ H-type passed by hard natural water; 25％ Na-type and 75％ H-type passed by soluble natural water) made higher yield of raw silk with tess breaks of thread. 6, In case cocoon ends groping water included sodium hexametaphosphate as much as 800 ppm. the groping efficiency and raw silk yield of cocoon was improved. The effect was pronounced in case of poor reelability cordons. 7. The most reasonable cocoon cooking and silk reeling condition for automatic silk reeling process were observed to be rather incomplete cook with good reelability cocoons and optimum cook with poor reelability cocoons succeeded by the reeling bath temperature of 45$^{\circ}C$, 8. The reasonable silk reeling velocities were observed to be about 150m per min. for good reelability cocoons, 120m per min. for fair reelability ones and 90 to 120m per min. for poor reelability ones. 9. In order to improve the raw silk yield of cocoons and reeling efficiency, the cocoon stand-by-ratio for reeling should be kept at the level of 40 per cent for good reelability cocoons or at 60 per cent for poor reelability ones beside necessary end found cocoon condition.

• International Journal of Industrial Entomology and Biomaterials
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• 제44권1호
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• pp.4-11
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• 2022

In this study, cocoons from different silkworm strains and rearing seasons were collected and immersed in water at elevated temperatures to investigate the effect of a wet treatment on their morphology and crystallinity. Untreated cocoons exhibited different crystallinities depending on the silkworm strain and rearing season; however, no distinct changes in their morphological structure were observed. Furthermore, after wet treatment, the differences in the crystallinities of cocoons disappeared. In addition, wet treatment of degummed silk (i.e., fibroin) did not change its crystallinity. These results indicate that different crystallinities of the untreated cocoons collected from various silkworm strains and rearing seasons are due to the different characteristics of sericin in the cocoons.

• International Journal of Industrial Entomology and Biomaterials
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• 제35권2호
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• pp.71-76
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• 2017

The cocoon's color of silkworm, Bombyx mori L. is usually white. But some are yellow, flesh and green colors because of modified characteristics. The yellow and flesh cocoons depend on carotenoid pigments, green cocoons are determined by flavonoid pigments. The cocoon's color is affected by the genes controlling penetration process from midgut to coelom and silk gland. Y (Yellow blood, 2-25.6) and I (Yellow-inhibitor, 9-16.2) genes are involved in the penetration process of carotenoid pigments from midgut to coelom, C (Outer-layer yellow cocoon, 12-7.2) and F (Flesh, 6-13.6) genes from coelom to silk gland. Therefore, the carotenoid cocoon's color depends on the genotype Y, I, C and F genes and their combination. Among them, C gene is sympathetic gene, which are known as C, CI and CD. C (Outer-layer yellow cocoon) genes make yellow cocoons on outer-layer and white cocoons on inter-layer, and CI (Inner-layer yellow cocoon) genes do yellow cocoons on inter-layer and dilute yellow cocoons on outer-layer. CD gene is known as making dilute yellow cocoons all layer. In this study, we have checked the dominance relation of C sympathetic genes among carotenoid genes for color cocoons by using strains related to the genes for color cocoons and investigated the aspect that pigments were penetrated in silk gland by action of each gene.

• International Journal of Industrial Entomology and Biomaterials
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• 제46권1호
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• pp.9-15
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• 2023

Recently, a silkworm strain (tentatively named Sericinjam) producing 100% sericin cocoons has been studied in South Korea. In this preliminary study, the crystallinity, mechanical properties, and dissolution conditions of sericin from Sericinjam cocoons were examined. The Sericinjam cocoon could be dissolved in water at high temperature (120℃) and high pressure (HTHP method) in an autoclave and in a CaCl₂/H₂O/EtOH mixture (ternary solvent method), resulting in 82% and 97% dissolution after 30 min, respectively. The solution viscosity of the silk sericin formic acid (SSFA) solution obtained from sericin extracted using the ternary solvent method was higher than that obtained using the HTHP method; however, SSFA solutions obtained from sericin extracted from conventional Baekokjam cocoons yielded a higher solution viscosity. The crystallinity and breaking strength of the sericin film from Sericinjam cocoons were slightly lower, respectively, than those from Baekokjam cocoons. In contrast, the elongation at break of the Sericinjam sericin film obtained using the HTHP method was higher than that of the Baekokjam sericin film.

• 한국잠사곤충학회지
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• 제51권2호
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• pp.142-146
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• 2013

최근 국내 농촌진흥청 국립농업과학원 연구팀에서 농가보급품종인 백옥잠(잠123 ${\times}$ 잠124)을 이용하여 피브로인 중쇄 유전자 내에 녹색형광유전자(EGFP)를 도입하여 녹색형광 누에고치를 생산하는 형질전환누에 개발에 성공한 바 있다. 그리고 녹색형광 누에고치는 견사의 주성분인 fibroin heavy chain 유전자에 삽입된 형광유전자의 발현으로 정련을 해도 형광단백질의 고유한 색깔이 그대로 유지되며, 자연광 하에서도 도입 형광유전자 고유의 형광색을 나타낸다. 그러나 형광누에고치는 기존의 $100^{\circ}C$ 내외의 고온 처리에 의한 건조, 자견 및 조사 방법을 이용하면 형광단백질에 심각한 변성이 초래되고 이로 인해 형광색깔을 잃게 되는 단점을 가지고 있다. 따라서 본 연구에서는 녹색형광 누에고치로부터 녹색형광단백질의 변성을 초래하지 않는 누에고치의 저온건조 방법, 저온 진공 감압 처리에 의해 고치 내강 내 침지액 침투방법 및 조사방법을 개발하여, 녹색형광 누에고치로부터 천연의 녹색형광색을 띄는 생사를 생산하였다. 그리고 이들 생산된 녹색형광 생사는 별도의 염색처리 없이 패션의류, 벽지, 조명등갓, 액세서리, 인테리어용품 등의 고부가가치 실크소재로 적용이 기대된다.

• 한국잠사곤충학회지
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• 제15권1호
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• pp.27-30
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• 1973

본 연구는 조사검정의 정도를 높이고 또한 조사검정을 보다 효율적으로 수행하는데 기여하기 위한 기초자료를 얻고자 하였던바 다음과 같은 결과를 얻었다. 1. 검정시료량에 대한 해서율 및 생사량비율의 표준편차와 변이계수는 시료량의 증가에 따라서 점차감소하는 경향을 보였는데 300입이상의 시험구에서는 시료량의 다소에 따른 유의차를 인정할 수 없었다. 2. 해서율에 대한 표준오차는 300 입구와 400 입구간의 유의차를 인정할 수 없었다. 3. 생사량비율에 대한 표준오차는 300 입구와 500 입구 및 600 입구간의 유의차를 인정할 수 없었다. 4. 견사장에 대한 표준편차, 표준오차 및 변이계수는 시료량의 다소에 따론 유의차를 인정할 수 없었다. 5. 이상의 연구결과를 종합하여 볼때 견사검정에 있어서의 적정시료량은 300입으로 추정된다.