• International Journal of Industrial Entomology and Biomaterials
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• v.7 no.1
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• pp.79-82
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• 2003

To study the effect of mounting fully ripe and unripe silkworms at different maturation percentage, the ripe and unripe silkworms were mounted separately and observed the cocoon and reeling characters. The significant difference in the cocoon and reeling parameters was observed between all ripe and unripe batches except for summer season. The silkworms collecting together and mounting at a time can be recommended only in summer season and at certain level during rainy season.

• Journal of Sericultural and Entomological Science
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• v.10
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• pp.59-62
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• 1969

It is very important physiological and economical problems to hatching within a day by increasing hatching-ratio of silkworm eggs in sericulture, and modified dark incubating method was experimented in Japan. The author studied on the economical problems of that rather than physiological study. Hatching was induced and accelerated by illumination before hatching 5 days which incubated in the dark room after eye spot pigmented eggs emerged 10-20 percentage. It was increased by 80-90％ in hatching-ratio, but the hatching was delayed a day. In autumn silkworm, newly hatched silkworms were hatched silkworms were hatched in the dark room because of high temperature period tough modified dark incubation was passed only 4 days. The author wonder which is more effective between effect of increasing the hatching-ratio and the health of silkworms.

• International Journal of Industrial Entomology and Biomaterials
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• v.37 no.2
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• pp.49-54
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• 2018

To artificially enhance antimicrobial peptide expression in Bombyx mori, we constructed genetically engineered silkworms overexpressing Rel family transcription factor. The truncated BmRelish1 (BmRelish1t) gene contained a Rel homolog domain (RHD), nuclear localization signal (NLS), acidic and hydrophobic amino acid (AHAA)-rich region, and death domain (DD), but no ankyrin-repeat (ANK) domain. The BmRelish1t gene was controlled by B. mori cytoplasmic actin 3 promoter in the PiggyBac transposon vector. Chromosome analysis of G1 generations of a transgenic silkworm with EGFP expression confirmed stable insertion of BmRelish1t. BmRelish1t gene overexpression in transgenic silkworms resulted in higher mRNA expression levels of B. mori antimicrobial peptides such as lebocin(~20.5-fold), moricin(~8.7-fold), and nuecin(~17.4-fold) than those in normal silkworms.

• Korean Journal of Organic Agriculture
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• v.11 no.1
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• pp.67-77
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• 2003

This study was conducted to established method of culture for Paecilomyces japonica using an egg. Mycelia grew favorably at the temperature of 22～26$^{\circ}C$ on eggs. 5.1g of dry matter basis(average 7.2cm of longer and 199.6 of numbers) of artificial fruiting bodies were harvested at 60 days after inoculation from one of egg. Commercial fruiting bodies of Paecilomyces japonica from silkworms was used for comparative nutriental contents. Cordycepin contents of fruit bodies of Paecilomyces japonica cultivated on eggs and silkworms were not significantly different. Crude fat contents of fruiting bodies of Paeilomyces japonica cultivated from eggs was significantly higher than from silkworms(P<0.05). Mn and Cu contents of fruiting bodies of Paecilomyces japonica cultivated from silkworms were significantly higher than from eggs(P<0.05), but Na, Mg, Fe and Zn contents were significantly higher from eggs(P<0.05). Glycine, Arginine and Proline contents in the fruiting bodies of Paecilomyces japonica cultivated from silkworms were tend to higher than from eggs, but Serine, cystein. methionine, isoleucine and phenylalanin were tend to higher from eggs. These results were made possible that possible mass production of artificial fruiting bodies of Paecilomyces Japonica cultivated on eggs.

• Journal of Sericultural and Entomological Science
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• v.21 no.2
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• pp.1-6
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• 1979

Diallel crosses among six silkworm varieties were used as the materials. by the randomized block design, and diallel cross analyse were conducted to determine the relationships between parents and their F$_1$hybrids. The six parents and their 30 F$_1$crosses were evaluated for five quantitative characters in each female and male silkworms. All methods utilized were similar in detecting lines giving unexpected performance in the F$_1$generation. Mean values of total cocoon weight and weight of cocoon layer of female silkworms were more than those of male silkworms, but mean values of cocoon layer ratio of female silkworms were less than those of male silkworms in both parents and 30 F$_1$hybrids. Over dominance was exhibited by total cocoon weight and weight of cocoon layer, and partial dominance was exhibited by periods (days) of larval stage, periods (days) of 5th instar and cocoon layer ratio (weight of cocoon layer/total cocoon weight). Furthermore, it was recognized that varieties F (Yunil) and E (Kyung-choo) were recommendable varieties as the parents in breeding of silkworms for increasing the total cocoon weight and weight of cocoon layer, etc.

• Journal of Sericultural and Entomological Science
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• v.13 no.2
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• pp.123-133
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• 1971

The author is the first man who tried to use an anesthetic on insect specially for silkworm in orde to evaluate the silkworm health and silk yielding ability and the obtained results are as followings. 1. The necessary ether vapor induction for narcosis on silkworms is varied by the glowth of the silkworm which the larger worm is, the longer induction is required. For instance, it was 2∼3 minutes for the worms of third day fifth instar silkworm in case use of ether anesthetic. 2. The longer anesthetic induction for silkworms, the longer recovery needs from anesthesia. In case five minutes ether vapor induction, silkworms recovered narcosis during in 5∼130 minutes which had varied very much by the health variation. 3. The ether induction caused silkworm to vomit digestive juice from a few per cent of the worms, but the chloroform induction showed majority of the worms to vomit the digestive juice out of mouth. So, the ether was found as better anesthetic for silkworms. 4. When ether induction last more than 20∼30 minutes, the recovered silkworms can eat mulberry, but when it gets more than three hours they can not eat mulberry. And when it last more than ten minutes, the silkworm may eat mulberry leaf, but they can not spinn cocoon properly. 5. In case five minutes ether induction for silkworms on third day fifth instar, the stronger variety is, the rallier recovered from narcosis. 6. The recovering duration from narcosis varies regarding with each worm health which shows Poisson′s distribution even in a same variety silkworm. 7. The female worms recover from narcosis earlier than male worms which means the female worm is stronger than male one. 8. The later recovered silkworm from narcosis spinned more rich cocoon silk and ended with smaller pupae weight. Such a tendency showed until at some recovery duration, then the silk yield droped down on the worms recovered in more longer duration. The author (Choe) had named such a relation curve as "Silk Yield Curve against Silkworm Health." 9. The silk yield or cocoon layer ratio had varied from 13 to 27% even in a same worm varity cocoon which showed serious variation and call attention carefulness for the duplication work of a variety silkworm eggs. 10. Not always the rich silk yielding worm is the best worm during the silkworm selection and it should be considered with the silkworm health evaluation. 11. At present situation, only specific breeding expert is allowed to join in the selection service because of need many years experience by use of visual observation, but the ether anesthesia method may help such an evaluation with more accuracy and easy way even for the people in fresh on the field. 12. The effect of the narcosis on the silkworm for the next generation or hybrid worm will be reported in next publication.

• Mycobiology
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• v.39 no.3
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• pp.158-163
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• 2011

This study was conducted to confirm the possible use of female Yangwonjam as a host for synnemata production of Isaria tenuipes in eight local areas in Korea. Silkworm pupation rate, infection rate and synnemata characteristics of I. tenuipes were examined. Normal silkworms had a higher pupation rate than silkworms inoculated with I. tenuipes. The pupae survival percentage of normal silkworm in cocoons was 92.5~97.6%, whereas it ranged from 91.1~95.6% in silkworms sprayed with I. tenuipes. Female Yangwonjam showed the highest survival percentage at 97.6% among the silkworm varieties tested. I. tenuipes infection rate of larvae of 5th instar newly-exuviated silkworms was 89.2~90.7% in the spring rearing season and 98.2~99.3% in the autumn rearing season. Synnemata production of I. tenuipes was excellent in female Yangwonjam with an incidence rate of 98.0% followed by male Yangwonjam (94.1%) and Baegokjam (93.3%) in the spring rearing season. Synnemata living weight ranged from 1.44~0.94 g in the spring rearing season. The female Yangwonjam had the heaviest synnemata weight (1.44 g) in the spring rearing season. The synnemata of I. tenuipes produced on pupae were white or milky-white in color, and were similar in shape and color to wild synnemata collected in Korea.

• Journal of Sericultural and Entomological Science
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• v.33 no.1
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• pp.27-31
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• 1991

Microsporidian spores were isolated from yellow-hind winged arctiid, Eilema griseola (Hubner), and cutworm, Agrotis tokionis Butler, and their morphological characteristics and their indectivity to silkworms were investigated. The shape of the microsporidian isolates was oval and the sige of the spore isolated from yellow-hind winged was measured in 2.6$\times$1, 5$\mu$ and that of the isolated from cutworm was measured in 3.7$\times$20.$\mu$. Both the isolated microsporidians showed the infectivity to silkworms, but the isolates did transovarian transmission in silkworms and the silkworm moth infected with the isolate from yellow-hind winged laid eggs irregularly.

• International Journal of Industrial Entomology and Biomaterials
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• v.31 no.2
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• pp.56-61
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• 2015

Rutin is an important bioflavonoid that is consumed in the daily diet. This study compared the functional components of rutin from various silkworm species using a gene database with those of rutin produced by silkworms selectively bred through cross-combinations. We made comparisons between the geographical origin and species of silkworm using a gene database and discovered that rutin activity was ranked in the following order by species, Chinese (C5)> miscellaneous varieties (Jamsaeng 1 Ho) >Japanese (Jam 115) > European (E58) >Korean (Sun 3 ho). However, rutin levels with respect to various genetic traits (blood color, silk color, and egg color) were consistent. In order to study rutin changes that occurred during the cross breeding of the silkworm gene, we bred cross-combinations utilizing Jam 115 and the 4051 silkworms. In conclusion, in order to provide information about the constituents of functional materials contained in silkworm powder, it is imperative that silkworm cross breeding occurs so that the database of functional materials extracted from silkworms will expand.

• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.77-80
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• 2000

This study was carried out to investigate infection process, symptoms and $LD_{50}$ values of the entomopathogenic fungus cordyceps, Paecillomyces japonica, on the domestic silkworm, Bombyx mori. Susceptibility of infection in the silkworms by cordyceps, Paecillomyces japonica, was 100% in $10^{7}$ block, 96% in $10^{6}$ block, 76% in $10^{5}$ block, 44% in $10^{4}$ block, 28% in $10^{3}$ block and 8% in $10^{2}$ block. Cordyceps, Paecillomyces japonica, was highly infectious to the silkworms. A pathogenicities of cordyceps, Paecillomyces japonica, may be highly virulent because of the low resistance or high susceptibility of the silkworms. Dosage of the pathogen of $LD_{50}$ was $3.78{\times}10^{3}\;spores/mm^{3}$.