• Journal of Life Science
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• v.9 no.2
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• pp.176-181
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• 1999

In order to understand molecular phylogenetics of silkworm (Bombyx mori), we analyzed the sequences of BmoMAR isolated from Bomhyx mori that is partial coding gene of transposase of mariner-like element(MLE). By pairwise comparing nucleotide sequences of BmoMAR with ten previously reported insect MLEs accessed in GeneBank, the average genetic distance was estimated to be 0.4840. The phylogenetics tree constructed from nine insect species except for human MLE(Hsmarl) by UPGMA method indicated that MLEs are divided into three clusters, and Drosophila mariutiana was independently subgrouped. Bombyx mori(BmoMAR) was subgrouped with microcaddishfly (Orthotrichia cristata), webworm(Atteva punctella), almond moth(Ephestia cautella), Hyalopora cecropia which we lepidoptera. Phylogenetics tree according to UPGMA principle, on the basis of informative nucleotide sequences of nine insect MLEs, indicated that Bombyx mori was more closely related to microcaddishfly(Orthotrichia cristata) and webworm (Atteva punctella) of lepidoptera. We suggest that insect MLEs are a useful key for studying molecular phylogenetics among intra species of insects.

• Journal of Sericultural and Entomological Science
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• v.32 no.2
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• pp.105-109
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• 1990

The disinfectivity of formalin fumigation was tested against silkworm nuclear polyhedrosis virus and yellow muscardine pathogen, Beauveria bassiana. The inactivation of the virus was acquired when it was fumigated by adding 30g of potassium permanganate to 75$m\ell$ of formalin per 3.3$m^2$ of rearing room area and viability of the yellow muscardine pathogen was also lost with the same treatment of fumigation. It was also proved that the fumigation didn't give and damage to silkworm larvae when it was applied 2 or 3 times to grown larvae.

• The Korean Journal of Mycology
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• v.30 no.1
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• pp.11-17
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• 2002

This experiment was carried out to study formation of fruitbody with Cordyceps scarabaeicola (EFCC C-252) isolate. This isolate was the one of best fruitbody formation on brown rice 60 g plus 30 g silkworm pupa media among EFCC C-251, EFCC C-252, EFCC C-1092 from EFCC (Entomopathogenic Fungal Culture Collection) of Kangwon National University. Fruiting body was formed only isolate EFCC C-252 among tested isolates on the medium of brown rice (60 g) and silkworm pupae (30 g). The optimal temperature and light for fruiting body formation were $25^{\circ}C$ and fluorescent light (300 lux). The maximal fruiting body formation was observed at 70 g of brown rice and 80 g of silkworm pupa medium which was treated separately. Fruiting body was formed maximally by 2 days interval of irrigation.

• Journal of Sericultural and Entomological Science
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• v.17 no.1
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• pp.55-62
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• 1975

In the studies of characterization of crystal prototoxin isolated from Bacillus thuringinensis var. alesti and its bioassay to the silkworm larvae, Bombyx mori L., the following results were obtained. 1. The complete lysis of bacteria grown on the nutrient agar at 30$^{\circ}C$ in an incubator took 30 days, but the period could be reduced by a half in a devised broth media in a fermentation jar. 2. The protein toxin extracted directly from a mixture of crystals and spores without separation of crystals and spores was pure as same as the protein toxin extracted from only crysals separated. 3. By SLS polyacrylamide gel electrophoresis of prototoxin released from crystals in alkali (pH 9.5) three different proteins in molecular weights of 120,000, 87,000, 74,000 were separated. 4. In the bioassay of the toxin to the silkworm larvae, LD$\sub$50/ per gram of the larvae in the 4th instar was 0.080 $\mu\textrm{g}$.

• Journal of Sericultural and Entomological Science
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• v.38 no.2
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• pp.108-112
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• 1996

This experiment was carried out to investigate the feeding effect of rutin (quercetin-3-o-${\beta}$-rutinoside) and ${\gamma}$-aminobutyric acid(GAB) sprayed on mulberry leaves on silkworm growth. Amount of ingest, digest and feces showed no difference statistically except rutin. Rutin made 6% increase of amount of digest, compared to the control. However, rutin or GABA decreased maximaly silkworm weight by 28% during the experimental period. GABA showed body weight loss by 15%, rutin by 7% respectively, compared to the control. Rutin and GABA extended three days larval period and extended one day mounting period and decreased 15.4% and 91% in number of mounted silkworm compared with the control, respectively.

• Korean journal of applied entomology
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• v.41 no.2
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• pp.85-89
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• 2002

Development and reproduction of the rice armyworm, Pseudaletia separara, were investigated on different diets (corn leaf, rice leaf, Chinese cabbage leaf, cabbage leaf, sweetpotato leaf, soybean leaf and silkworm artificial diet). Egg and pupal periods were not different among the diets. But larval periods showed significant difference among diets. Developmental period from egg to adult was shortest as 32.5 d on corn leaf and longest as 46.6 d on soybean leaf. At 16 days after hatching, larval weights on rice and silkworm artificial diet were heavier than those on other diets. The larvae reared on cabbage leaf and sweetpotato leaf failed to pupate. Survival rates from larva to adult were highest (70.6%) on com leaf lowest (39.8%) on soybean leaf. The longevity of female adults was not affected by the larval diets. Female adults showed higher fecundity when the larvae were fed with corn leaf, rice leaf and silkworm artificial diet than other diets. Net reproduction rate (R$_{0}$) was highest as 1218.5 on silkworm artificial diet. The intrinsic rate of natural increase (R$_{0}$) ranged from 0.115 to 0.175, and was maximum on com leaf.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.283-291
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• 2006

The efficiency to detect mutagenicity of the system using a specific locus mutation of Bombyx mori was examined and improved. In the system, mutagenicity could be detected by the egg colour manifested by the pe and/or re genes, which is a kind of recessive visible mutation of the insect. Among tested four mutagens, MMC had specially high sensitivity in the oocytes of silkworm and EMS had in the spermatozoa. PCB and dioxin showed a positive effect in both the oocytes and spermatozoa. In a consequence of sensitivity of mutagen by mating number of male moth of B. mori, treated mutagen, there was no difference between one mating - and three mating - male moth in sensitivity of mutagen. Sun3ho, B. mori variety, which showed high sensitivity to mutagens was improved in the major characteristics by crossing of C5 and N12.

• Korean journal of applied entomology
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• v.38 no.2
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• pp.129-138
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• 1999

This study was carried out with two types of silkworm, Bombyx mori, adults having different life span: long life span (adult living for more than fifteen days; LLS), and short life span (adult living less for than five days; SLS). The fine structures of fat body cells in the young and the senescent males and females were compared in an attempt to elucidate the aging physiology of the silkworm adult. In SLS, there were many rough endoplasmic reticula (RER) and glycogen granules in the female cytoplasm, whereas the smooth endoplasmic reticula (SER) were observed in the male cytoplasm. Also in SLS, the mitochondria were swollen and had many poor osmiophillic inclusions (fatty degeneration) at three days after emergence. In LLS, compared to SLS, comparatively normal mitochondria and nuclear membrane were observed in even five day old female. In fifteen day old LLS female, however most of cell membranes were disappeared and mitochondria were abnormally expanded. Many fat granules were observed in the cytoplasm of ten day old male (LLS) which died with full autophagic vacuole (AV) collapsed at fifteen days. Therefore, it is suggested that SLS type is recommended for the study of aging tissue, because it is easier to monitor the changes in tissue structure.

• Journal of Sericultural and Entomological Science
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• v.35 no.2
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• pp.86-88
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• 1993

The effect of short term duration(1, 2 and 3 days) after urea foliar spray on leaf quality was investigated by chemical analysis of leaves and silkworm rearing with leaves treated with urea in autumn. Foliar spray increased water content by 0.4~0.7% and total nitrogen by 0.19~0.51% in leaves compared to the conventional treatment. Foliar spray increased NO3-N concentration in leaf 503~1107 ppm more than the conventional treatment. NO3-N concentration in leaf decreased with days after foliar spray. Whole cocoon weight and cocoon shell weight increased by 0.02~0.14g and 0.5~3.1 cg, respectively in foliar spray than in the conventional treatment. Though foliar spray raised NO3-N concentration in leaf, leaves harvested one day after foliar spray were no harmful to silkworm.

• Korean journal of applied entomology
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• v.59 no.4
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• pp.451-454
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• 2020

Sericulture is a main insect industry in Sangju (Kyungpook, Korea). This study reports an occurrence of a viral disease in the sericulture farms in 2020. More than 20% silkworm larvae (Bombyx mori) suffered diarrhea and melted tissues with pathogenic lethality at 4th or 5th instars. PCR diagnosis showed a positive response against B. mori nucleopolyhedrosis virus (BmNPV) infection. Tissue extract of the infected larvae was applied to healthy larvae by a leaf-dipping method and exhibited the same viral symptoms. The viral extract was used to be overlaid on Sf9 cells. The infected Sf9 cells showed polyhedra in the cytoplasm. These results indicate that the silkworm larvae reared in the sericulture farms in Sangju were infected with BmNPV.