• International Journal of Industrial Entomology and Biomaterials
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• v.43 no.1
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• pp.29-36
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• 2021

Silkworms have long been bred with human history to produce silk. It has been with humans for longer than other industrial insects, and the silkworm variety has been continuously improved. Silkworms have been developed into the optimal form for producing high quality silk and pupae. Recently, the production of transgenic silkworms has further expanded the possibility of industrial value of silkworms. Kynurenine 3-monooxygenase (KMO), which is a flavin enzyme, is known for its involvement in ommochrome pigment synthesis. In the field of mammals, including humans, previous studies have revealed the function and role of KMO, which is an important enzyme for various immune responses and cell protection. However, in the case of insects, the function of KMO has only been studied to be involved in the formation of pigment, and accordingly, KMO is used exclusively on screening for generation of transgenic insects as a marker. In this study, using KMO-edited silkworms, it was intended to discover the novel functions and roles of KMO in silkworms by identifying changes in the expression of various genes associated with stress and growth. The changes were observed in expressions of genes regulating on stresses to survive and those on ecdysteroid hormone between wild-type (WT) silkworms and kmo mutant silkworms. The loss of KMO, in particular, decreased the expression of the shadow (sad) gene, one of the Halloween genes in the synthesis of ecdysteroid. In conclusion, these results suggest that silkworm KMO is responsible for potential functions regarding stress response and ecdysteroid synthesis.

• The Korean Journal of Pesticide Science
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• v.11 no.4
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• pp.299-304
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• 2007

Surveying, laboratory and field trial were performed to elucidate the causes of non-spinning syndrome of silkworm, Bombyx mori, abnormal symptoms of silkworm instars observed in certain sericultural fanning region. Mortality and growth of silkworm was still influenced by feeding the mulberry leaves sprayed with 10,000 fold diluted solution of standard spray of diflubenzuron WP (25%). Mortality and growth of silkworm fed with diflubenzuron-sprayed mulberry leaves with recommended spray solution were entirely affected even six weeks after spraying irrespective to the instars. Larval period of 5th instar and cocooning duration of silkworm was not affected in case 50m of buffer zone has maintained in near-by orchard field sprayed with diflubenzuron WP (25%). However, survival rate of pupae was not influenced in case 100 m of buffer zone has kept. Insect growth regulating insecticides were required to keep a certain distance of buffer zone when sprayed with water-diluted solution, 100 m from the application site at least in order to prevent contamination of the spraying drift by the chemicals.

• Journal of Sericultural and Entomological Science
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• v.36 no.1
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• pp.69-75
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• 1994

Through the histological and anatomical investigation of silkworm gonad, N. bombycis infection was found to begin from the peripheral region of ovarial sheath or testicular sheath, then, the pathogens spread to the inner portion. Peroral inoculation with purified spores of N. bombycis to 2nd instar larvae at dosages around 106-8/㎤ of artificial diet resulted in the extremely extended larval survival as long as 15 to 22 days of 4th instar. The growth of ovarioles was confirmed in the 10 to 14 day old larvae, oogonia developed into oocytes and nurse cell against heavy infection of the ovary. Gonads rarely obstructed oogenesis and spermatogenesis in the pupae failed in adult eclosion. Light infection of female hosts effected insignificantly on the ovarial development, however, recorded 100% transmission of the pathogens to the progeny populations. Conclusively, ovarial inflection of silkworm induce transovarial transmission begins around 2~3 day old pupae when ovarioles extruded out to hemocoel, and the infection period thought to be continued until the stage of eggs complete shell formation in the ovariole.

• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.2
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• pp.277-281
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• 2013

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 $150^{\circ}C$, 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 $60^{\circ}C$ (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 $100^{\circ}C$ but not at $150^{\circ}C$.

• Journal of Sericultural and Entomological Science
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• v.39 no.1
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• pp.17-21
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• 1997

Oral application of fenoxycarb, O-ethyl N-(2-(4-phenoxyphenoxy)ethyl) carbamate, the commercial formulation Insegar, on the 1st day of the 3rd instar made no difference in the egg laying and the hatchability as compared to 750 grains for the number of eggs laid, 53 grains for the number of the resideual eggs unlaid, 749 grains for the number of fertirized eggs, 97% for the total hatchability, and 95% for the useful hatchability as in the control but on the first day of the 4th instar, the number of the remainder eggs in the ovary increased by 2.4 folds, and reduced number of the eggs laid, number of unfertilized eggs, the hatchabillity and useful hatchability by 39%, by 66%, by 68% and by 72%, respectively. When diluted Insegar was applied topically every other two days from the pupae to the moth at concentration of 10-6, 10-7, 10-8, 10-9, 10-10 the number of eggs laid, the number of the unfertilized eggs, the total hatchability and the useful hatchability were decreased. More severe decrease took place as concentration lowered and the earlier application.

• International Journal of Industrial Entomology and Biomaterials
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• v.20 no.2
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• pp.75-77
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• 2010

Until now, the main treatment for impotence has been the vasodilator injection, penile implants and etc. Among many methods, most effective way is known to be the medical therapy. The oral drug for an impotence remedy has to be above all, effective to the erection, and second, safety when taking in long-term. However, so far the drug in such condition and sufficiency has not been discovered. Consequently, it is crucial to develop the new medicine, made of natural materials only, without any uncertainty of side effect. The silkworm is very difference in physiological chemical change according to growth stage. Therefore the functional effect shows a very big difference according to preparation method with a growth stage. This research carry out the experiment with the pupa powder immediately before the eclosion, eclosion adult, the pupa extract immediately before the eclosion, and the silkworm powder of 5 instar 3rd day. The result showed not a big chance in weight, feed and water intake quantity. But testosterone hormone secretion effects of the freeze drying powder of the pupa immediately before the eclosion was very high 7.31 ng/ml, compared to 2.37 ng/ml of non treatment and 2.67 ng/ml of alcohol extraction method. As this result, the freeze drying pupa powder of the pupa immediately before the eclosion was confirmed to promote the secretion of the testosterone hormone more than alcohol extraction method of existing.

• International Journal of Industrial Entomology and Biomaterials
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• v.22 no.1
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• pp.17-20
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• 2011

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 $3^{rd}$ day of $5^{th}$ 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.

• Journal of Mushroom
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• v.3 no.4
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• pp.133-139
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• 2005

Fruiting bodies of Cordyceps have been regarded as popular folk and effective medicines to treat human diseases such as asthma, bronchial and lung inflammation, and kidney disease. Cordyceps pruinosa (Clavicipitaceae; Hypocreales; Ascomycotina) has received special attention for medicinal purpose due to its various physiological activites. The nucleoside derivative N6-(2-hydroxyethyl) adenosine (HEA) isolated from it showed a $Ca^{2+}$ antagonistic effect and negative inotropic response. The artificial production of fruiting body of C. pruinosa has not been tried successfully yet by using living silkworm substrate. To develop techniques for the production of C. pruinosa stromata on a large scale, the infection of Bombyx mori with C. pruinosa and the growth characteristics of stroma of C. pruinosa were investigated. Also, studied about biological activities of fruiting body formed on silkworm. Infection rate of the silkworm pupae with C. pruinosa was the highest in injection inoculation. The formation of the fruiting body of C. pruinosa was quite good in the room controlled at $21{\sim}25^{\circ}C$, over 91% of relative humidity and over 1500 lx. Glucose concentration was high in the fruiting bodies of the silkworm pupae infected with C. pruinosa on a dry weight basis. The most abundant amino acid in the fruiting bodies was arginine and phenylalanine. The fruiting bodies of silkworm pupae infected with C. pruinosa was rich in oleic acid. The high amount of citric acid was found in the fruiting bodies of silkworm pupae infected with C. pruinosa.

• Journal of Sericultural and Entomological Science
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• v.8
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• pp.51-62
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• 1968

This study was carried out to investigate the life cycle and the damage of Tricholyga sorbillans Wiedmann to silkworms(Bombyx mori L.). The results are summarized as follows. 1. This insect has 5 or 6 generations per year in Suwon area. 2. The egg, larval, and pupal stage are about 2, 8 and 18 days respectively. 3. The weather conditions considerably affect the life cycle, that is, the 3 rd generation is the shortest of all, lasting for 21 days and l4 hours, and the 5th generation is the longest for about 40 days. 4. The larvae come out of silkworm bodies, burrowing into the ground 3.5cm to 10.5cm in depth before changing into the pupae. 5. This insect does not overwinter as pupa, but seems to do as larva, parasiting on the field insects. 6. The damage of Tricholyga sorbillans Wiedmann to silkworm was 27.9％, it is so high that the silk worms could not be reared outside without a reasonable control method. 7. When the full-grown silkworm is parasited by one egg of these insects, there is not only enough possibility of spinning. but also without any effects of their larvae on the cocoon quality. 8. The damage of Tricholyga sorbillans Wiedmann throughout the country covers 6.36％ in spring, 4.09％ in fall, and 5.25％ yearly mean.

• Journal of Sericultural and Entomological Science
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• v.4
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• pp.51-55
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• 1965

The aim of this work was to investigate the rate of hybrid vigor among the $F_1$ hybrids. The results obtained are as follows; 1. The rate of hybrid vigor in outbreedings(E$\times$J, ＆ J$\times$C) was higher than that in inbreedings in all the metric characters, especially in moulting laval weight. 2. In outbreedings, the $F_1$ between Europe and Chinese strain showed considerably higher rate of hybrid vigor than that of Japanese and Chinese. 3. The hybrid vigor rate of moulting larvel weight gave rise to be significant differences among the strains due to the maternal effects from newly hatched larvae to pupae.