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In order to understand the diversity and genetic relationships of silkworm strains preserved in Korea, we genotyped 78 Bombyx mori strains (Bombycidae: Lepidoptera) originating from Japan, using eight polymorphic microsatellite loci. We obtained per-locus allele numbers ranging from 5 to 16 (with an average value of 9.1), per-locus observed heterozygosity ranging from 0.13 to 1.00, and per-locus polymorphic information content ranging from 0.36 to 0.77, indicating that some loci are highly variable. Phylogenetic analysis with the eight concatenated microsatellite loci showed no clustering based on known strain characteristics and origin. Nineteen strain-specific apomorphic alleles, which discriminated 16 of the 78 silkworm strains, were obtained from eight loci. These strain-specific alleles can thus be utilized for routine discrimination of strains from Japan, without any further typing of other loci. Homozygotes were also observed at some loci (27 of 118 genotypes), which can also be used to discriminate several strains by typing a few loci. These results showed that eight microsatellite loci described herein were sufficiently variable to discriminate among the 78 silkworm strains we examined, and may be useful for future investigations of this economically important species.

Silkworm powder, which contains 1-deoxynojirimycin (DNJ), is a promising complementary and alternative medicine (CAM) in Korea. Silkworm powder was produced from Yeonnokjam pupae at d 3 of the 5th instar at the National Academy of Agricultural Science. The powder was derivatized with 9-fluorenylmethyl chloroformate (FMOC-Cl), and the DNJ-FMOC content was measured by HPLC. We investigated the content of 1-DNJ in the silkworm powder and its glucose-lowering effect when it was treated at different temperatures. The content of 1-DNJ was the lowest at 150℃, while it was constant at other temperatures. The silkworm extract powder was orally administered to diabetic mice (20 mg/kg/d) for 4 wk. Water intake did not significantly change when compared with the control group (T0). The blood glucose levels significantly decreased when mice where administered silkworm powder treated at 60℃ (T60) compared to the control group, but no difference was observed between the groups T100 and T150. Moreover, the blood levels of TG significantly decreased compared with the control group. Based on these results, we surmise that the properties of the silkworm extract powder were stable upon heating at 100℃ but not at 150℃.

A total of 85 Chinese-origin silkworm strains preserved in Korea were genotyped for eight polymorphic microsatellite loci. We obtained per-locus number of alleles, ranging from 5 to 14 with an average value of 9.5, perlocus observed heterozygosity, ranging from 0.07 to 0.99, and per-locus polymorphic information content PIC), ranging from 0.34 to 0.82, indicating that some loci are highly variable. Phylogenetic analysis with the eight concatenated microsatellite loci showed no clustering on the basis of known strain characteristics. A total of 22 strain-specific apomorphic alleles, which discriminate 19 among 85 silkworm strains were obtained from eight loci. These strain-specific alleles, thus, can casually be utilized for the discrimination of applicable strains without any further typing of other loci. Furthermore, a substantial number of homozygote strains, represented by 27 among 76 alleles in eight loci were found. These results collectively suggest that the silkworm microsatellite DNA is actually and potentially important molecular markers for the eventual discrimination of silkworm strains that are preserved as hundreds in Korea.

Osteoporosis is characterized by the reduced density of mineralized bone matrix. The loss of bone has been attributed to an imbalance between bone formation and bone resorption. The silkmoth is one of the famous traditional tonic medicines. Silkworm pupa was evaluated for its antiosteoporotic activity in an ovariectomized rat model of osteoporosis. The rats were ovariectomized at 6weeks of age and divided into 7 groups. All the groups were fed without calcium diet. The OVX rats were treated with water and silkworm powder for 6 weeks. In OVX rats, the body weight, feeding and water intake quantity did not show a significant change, but the silkworm pupa powder immediately before the eclosion of Yeonrokjam was significantly increased the bone mineral density in the femoral bone. The silkworm pupa powder increased the bone with increasing calcium in serum. These results also showed its protective action through promotion of bone formation. The silkworm pupa powder has a definite antiosteoporotic effect; similar to estrogen, it is especially effective for the prevention of bone fracture induced by estrogen deficiency. The silkworm pupa powder is a promising anti-osteoporotic agent that can prevent bone fractures in osteoporotic patients. The silkworm pupa powder does not show serious side effects because natural herbal medicine origin.

The effect of cultivation season on the cocoon filament quality of authorized silkworm variety, GoldenSilk was examined with cocoon filament character, reeling character, and fiber character during 3 years. In cocoon filament character, filament length of spring and autumn cocoon was 979 and 879 m, respectively. Cocoon filament weight of spring and autumn cocoon was 33.1 and 26.5 cg, which is lower than that of general bivoltine strain, BaeGokJam. Raw silk percentage of spring and autumn cocoon was 15.65 and 13.77%, respectively. In reeling character, reelability showed similar trend regardless of cultivation season and strain. However, the length and weight of non-broken filament of spring season were slightly higher than those of autumn cocoon. Cultivation season did not affect on the fiber characteristics such as clearness and neatness, lousiness, and degumming loss. In cocoon character, filament length, size, and weight, spring cocoon filament showed higher value than autumn cocoon, but lower than authorized general silkworm varieties. In reeling characteristics, non-broken length and weight showed the similar trends with the cocoon filament character. However, the reelability of GoldenSilk cocoon was not affected by cultivation season. The reelability of GoldenSilk cocoon was also similar with that of authorized general one. Fiber character including clearness and neatness, lousiness, and degumming loss was also similar regardless of the rearing season and different strain.

Normally the first generation of hybrid is supplied for farm rearing, precise and labor saving sex discrimination is needed. The new strain "Hansaengjam" is sex-limited (female:larval markings, male:no-markings) strain which was bred from both sex-limited strain Japanese originated Jam 153 and Chinese originated strain Jam 154. Productivity test of Hansaengjam during 2007 and 2009 showed high healthiness and cocoon yield. The Hansaengjam is evaluated as an excellent strain from healthiness, cocoon yield and other test results.

Yeonnokjam is a newly bred high yield special silkworm strain for spring rearing, bred from Japanese originated green cocoon spinning strain Jam 315 and Chinese originated white cocoon spinning strain Jam 316. This strain showed high hatching ratio of 96% and high healthiness of 96.7% of pupatin ratio. And its spins heavier cocoon with somewhat shorter fiber length but thicker fineness. The merits of these_strains are short larval period and labor saving, and its breeding goals are producing polish green silk and use for education.

The average life expectancy has continuously increased with the development of medical industry. As women get older, they experience the deficit of estrogen caused by decreased function of ovarian. Specifically, they suffer from temporary fever because of unstable vasomotion and, in the long term experience, degeneration of urogenital organs, tooth loss, arteriosclerosis, demantia, snores and so on. Because of these symptoms the estrogen medical supply is getting required. Along with this, many studies have conducted to find out substitutional medicals without any side effects. This research was carried out to find out such substitutable materials. For the purpose of study, we examined the change of estrogen using the rats fed with the pupa powder immediately before the eclosion, eclosed adult, the pupa extract immediately before the eclosion, and the silkworm powder prepared at day of instar. The result showed no significant chance in weight, feeding and water intake quantity among variables. However, the estrogen hormone secretion effects was very high at 73 pg/ml in the rats fed with the freeze-dried powder of the Yeonnokjam male pupa prepared immediately before the eclosion, compared with the control at 59 pg/ml. The next was Yangwonjam male adult at 71 pg/ml.

In order to produce the colored cocoons we finalized the adequate amount of dyes throughout several trial and error experiments. The proper amount of each dye required for per 100 g of each colored cocoon turned out to be 150 mg of Rhodamine, 1560 mg of Thionin, 170 mg of Neutral red, and 200 mg of N-Blue, respectively. With this amount of dyes silkworms grew without physiological disorders. In order to produce colored cocoons, artificial diet composed mainly of mulberry leaves was fed to silkworms from the beginning of 5th instar, and subsequently fed with dye included diet from day of the 5th instar. This process resultantly produced colored silkworm body from the onset of feeding and subsequently colored cocoons and eggs. Nevertheless, the dye induced color was not inherited to next generation.