• Title, Summary, Keyword: silkworm

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Molecular conformation and crystallinity of white colored silkworm cocoons with different silkworm varieties

  • Park, Bo Kyung;Nho, Si Kab;Um, In Chul
    • International Journal of Industrial Entomology
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    • v.38 no.1
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    • pp.18-23
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    • 2019
  • Bombyx mori silkworm has many silkworm varieties and the structure and properties of silk can be varied depending on the silkworm variety. Therefore, the choice of proper silkworm variety can be an effective way to control and improve the performance of silk materials in biomedical and cosmetic applications. As a preliminary study, in the present study, thirty nine Bombyx mori silkworm cocoons were prepared and their molecular conformation and crystallinity were examined. Molecular conformation and the crystallinity of silkworm cocoons were different depending on the silkworm variety. Interestingly, the crystallinity index of outside of cocoon was different from that of inside of cocoon and the difference between the crystallinities of outside and inside of cocoon was varied depending on the silkworm variety. In this study, the silkworm variety cocoons were classified into three groups (Group 1, Group 2, and Group 3) based on the difference of crystallinities between outside and inside.

Crystallinity of yellow colored silkworm variety cocoons

  • Park, Bo Kyung;Nho, Si Kab;Um, In Chul
    • International Journal of Industrial Entomology
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    • v.38 no.2
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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.

Evolutionary dynamics of transposable elements during silkworm domestication

  • Han, Min-Jin;Xu, Hong-En;Xiong, Xiao-Min;Zhang, Hua-Hao
    • Genes and Genomics
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    • v.40 no.10
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    • pp.1041-1051
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    • 2018
  • Although there are some documented examples on population dynamics of transposable elements (TEs) in model organisms, the evolutionary dynamics of TEs in domesticated species has not been systematically investigated. The objective of this study is to understand population dynamics of TEs during silkworm domestication. In this work, using transposon-display we examined the polymorphism of seven TE families [they represent about 59% of silkworm (Bombyx mori) total TE content] in four domesticated silkworm populations and one wild silkworm population. Maximum likelihood (ML) was used to estimate selection pressure. Population differentiation and structure were performed by using AMOVA analysis and program DISTRUCT, respectively. The results of transposon-display showed that significant differentiation occurred between the domesticated silkworm and wild silkworm. These TEs have experienced expansions and fixation in the domesticated silkworm but not in wild silkworm. Furthermore, the ML results indicated that purifying selection of TEs in the domesticated silkworm were significantly weaker than that in the wild silkworm. Interestingly, an adaptation insertion induced by BmMITE-2 was found, and this insertion can reduce the polymorphism of the flanking regions of its neighboring COQ7 gene. Our results suggested that TEs expanded and were fixed in the domesticated silkworm might result from demographic effects and artificial selection during domestication. We concluded that the data presented in this study have general implication in animal and crop improvements as well as in domestication of new species.

Cocoon Characteristics of Antheraea pernyi Silkworm Reared in Korean Oak Field

  • Shin, Bong-Seob;Jeon, Jong-Young;Kim, Jong-Ho
    • International Journal of Industrial Entomology
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    • v.25 no.2
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    • pp.205-208
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    • 2012
  • Antheraea pernyi silkworm is a well known wild silkworm to produce a valuable silk fiber. A. pernyi silkworm was reared in Korean oak field and examined the cocoon characteristics, such as cocoon weight, cocoon shell weight, and percentage of cocoon shell weight. Degumming loss was also measured after alkali degumming process. A. pernyi silkworm spins tawny color cocoon in oval shape. Cocoon shell weight of A. pernyi silkworm, 0.78 g, was heavier than that of B. mori silkworm, 0.51 to 0.63 g. Cocoon shell percentage of A. pernyi silkworm, 32.8%, was higher than that of B. mori silkworm, 23.4 to 25.2%. Degumming loss percentage of A. pernyi silkworm, 17.1%, was lower than that of B. mori silkworm, 25.0%. SEM showed that the surface of the cocoon filament was coarse and oriented with longitudinal direction.

Isolation of a New Microsporidian sp. (NIK-5hm) forming Spores within the Haemocytes of Silkworm, B. mori L.

  • Selvakumar T.;Nataraju B.;Chandrasekharan K.;Sharma S. D.;Balavenkatasubbaiah M.;Sudhakara Rao P.;Thiagarajan V.;Dandin S. B.
    • International Journal of Industrial Entomology
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    • v.11 no.1
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    • pp.63-69
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    • 2005
  • While observing silkworm larval samples received from field, microsporidian spores formed within the haemocytes of silkworm haemolymph were observed. The spores of microsporidian sp. were purified and characterized for morphological characters viz., size, shape as well as serological affinity with different Nosema spp. (M$_{11}$ and M$_{12}$). The infectivity of the isolated spores to silkworm was also studied. The microsporidian sp. was found to be highly pathogenic to silkworm, B. mori. The isolated microsporidian sp. was designated as NIK-5hm, which formed ovocylindrical spore in the haemocytes of silkworm and differed in spore size (length, 4.55 $\mu$m & width, 2.10 $\mu$m) and shape from Nosema bombycis (NIK-ls), NIK-2r (Nosema sp. Mysore [3.6 & 2.8 $\mu$m]), NIK-3h (Nosema sp. M$_{11}$ [3.8 & 1.8 $\mu$m]), NIK-4m (Nosema sp. M$_{12}$ [5.0 & 2.1 $\mu$m]) and Lb$_{ms}$ (Nosema sp. in Lamerine breed of silkworm [4.36 & 2.14]). In immonological test (Latex agglutination test), the isolated microsporidian spores did not react with antibody sensitized latex particles of N. bombycis, M$_{11}$, M$_{12}$ and Lb$_{ms}$ and thus are different type of microsporidian sp., parasitic to silkworm, Bombyx mori L.

Silkworm-food plant-interaction: search for an alternate food plant for tasar silkworm (Antheraea mylitta Drury) rearing

  • Deka, Manabendra;Gargi, Gargi;Kumar, Rajendra;Yadav, Harendra;Sahay, Alok
    • International Journal of Industrial Entomology
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    • v.30 no.2
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    • pp.58-63
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    • 2015
  • An experimental rearing of tropical tasar silkworm, Antheraea mylitta Drury was conducted to study silkworm-food plant-interaction and thereby to search for an alternate silkworm food plant. The silkworm-food-plant-interaction was studied with six different food plant species viz. Terminalia tomentosa, Terminalia arjuna, Terminalia belerica, Terminalia chebula of Combretaceae family and Lagerstroemia speciosa, Lagerstroemia parviflora of Lythraceae family. The rearing performance of silkworm on Lagerstroemia speciosa in terms of cocoons per DFL and silk ratio was found comparable with Terminalia tomentosa and Termonalia arjuna, the primary tasar silkworm food plant species. These three plant species also possessed better results in terms of physiological (leaf moisture content and net photosynthesis rate) and biochemical (Chlorophyll, protein, carbohydrate and crude fibre contents) characteristics to support silkworm rearing than Terminalia belerica, Terminalia chebula and Lagerstroemia parviflora. The correlation study between silkworm rearing performance and food plant's constituents indicates commercial perspective of Lagerstroemia speciosa as an alternate food plant for tasar silkworm rearing.

An Activity of Lowering Blood-glucose Levels Accoring to Preparative Conditions of Silkworm Powder (누에분말 제조 조건에 따른 혈당강하효과)

  • 류강선;이희삼
    • Journal of Sericultural and Entomological Science
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    • v.39 no.1
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    • pp.79-85
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    • 1997
  • Bombyx mori, silkworm powder has been studied for blood-glucose lowering activity by National Sericulture & Entomology Research Institute(NSERI) and Kyung Hee University group in 1995. To obtain the optimum preparative condition of silkworm powder for lowering blood-glucose levels in postprandial time, blood-glucose lowering activity of mulberry & silkworm varieties were examined. In mulberry varieties, Samkwangjam showed the highest activity. Activity for lowering blood-glucose levels of autumn rearing silkworm was higher than that of spring silkworm and hybrid silkworm showed higher activity than that of parent silkworm. In the silkworm lines, Chinese lines showed higher activity than that of Japanese lines. In experiments to see the difference in blood-glucose lowering activity between either male and female or larvae and pupae, activity of larvae was higher than that of pupae and the male was higher than female. The heating dry and artificial diet showed lower than mulberry diet and normal freeze dry of the 5th instar 3rd day. Among the sericultural products, larvae showed the highest activity.

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Morphology, molecular conformation and moisture regain of cocoons of different silkworm varieties

  • Choi, Hui Ju;Noh, Si Kab;Um, In Chul
    • International Journal of Industrial Entomology
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    • v.40 no.1
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    • pp.6-15
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    • 2020
  • Silk has attracted the attention of numerous research groups because of its unique properties as a biomedical material. Recently, studies on the biomedical application of silk cocoon, such as membranes for guided bone regeneration, have been conducted. As a preliminary study on silkworm cocoons, the morphological structure and crystallinity of cocoon of nine silkworm varieties with different sides are examined in this study. The morphological structure of the silkworm cocoon is shown to be dependent on silkworm variety and the cocoon layer (i.e. outside or inside). It is also shown that the silk filaments of the out layer are more bent and twisted compared to those of the inner layer. Furthermore, the crystallinity of the outer surface of all silkworm cocoons is found to be higher than that of the inner surface, regardless of the silkworm variety. Lastly, it is shown that the crystallinity index of the cocoon depends on the silkworm variety, implying that the structure of the cocoon varies with silkworm variety.

The Physicochemical Properties and Sensory Evaluation of Jelly with Silkworm Powder (누에 분말을 이용한 젤리의 이화학적 특성 및 관능 평가)

  • Kim Ae-Jung;Yuh Chung-Suk;Bang In-Soo;Park Sang-Hyun
    • Journal of the East Asian Society of Dietary Life
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    • v.16 no.3
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    • pp.308-314
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    • 2006
  • This study was carried out to investigate the physicochemical quality characteristics of Nouaejelly(jelly using silkworm powder) sericultural products which were manufactured using various levels(0.5, 1, 1.5 and 2%) of silkworm powder. The effects of an additional amount of silkworm powder to Nouaejelly were determined by examining, the physicochemical, sensory, and textural properties. The moisture and crude protein content of the Nouaejelly were higher than that of the control(p<0.05). However, the crude fat content of the Nouaejelly was lower than that of the control(p<0.05). The mineral content increased with increasing addition of silkworm powder. The color of the Nouaejelly became darker with increasing levels of silkworm powder. For the texture measurements, the hardness, gumminess and chewiness of the Nouaejelly decreased with increasing levels of silkworm powder, but those of the jelly were decreased significantly by adding 0.5% silkworm powder(p<0.05). In terms of color, the texture and overall preference of Nouaejelly was highest in the jelly containing 1 % silkworm powder(p<0.05). Overall, the optimal amount of silkworm powder added in the manufacture of Nouaejelly was 1% of the total weight.

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Comparison on Antioxidative Capacity of Various Silkworm Strains

  • Ryu, Kang-Sun;Kang, Pil-Don;Jung, I-Yeon;Kim, Kee-Young;Sohn, Bong-Hee;Lee, Heui-Sam;Kim, Hyun-Bok;Lee, Kwang-Gil
    • International Journal of Industrial Entomology
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    • v.18 no.2
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    • pp.63-67
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    • 2009
  • To increase utilities as functional materials, 173 strains of silkworm genetic resources in the form of silkworm powder were evaluated for antioxidative capacity, with minilum L-100 device and ARAW-KIT (anti-radical ability of water soluble substance). Silkworm powder was prepared with freezing method from silkworms at 5th instar 3rd day larvae. All strains of silkworm powder were prepared with 80% methanol extraction. The data of pupation rate, longevity of silkmoth with origin and voltinism were used for data base of silkworm genetic resources. The weight of a silkworm larva with freezing method at 5th instar 3rd day was measured. The average of antioxidative capacity of 173 silkworm strains was 429.68 nmol. The analysis of correlation among variables was significant, showing negative correlation of the antioxidative capacity with longevity of silk moth and weight of 5th instar silkworm larva. The strains from the tropic, Europe and some other origins were comparatively high. In conclusion, short longevity and low weight of 5th instar silkworm larvae showed comparatively effective antioxidative capacity.