• 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.

• Journal of Sericultural and Entomological Science
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• v.52 no.2
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• pp.159-164
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• 2014

In this study, functionality of products of silkworm hemolymph fermented by Bacillus species was studied such as cell viability, antioxidant effect, and inhibitory effect on tyrosinase activities. A matured silkworm hemolymph was degraded by fermentation with Bacillus subtilis 10854 and Bacillus amyloliquefaciens M27. Especially, proteins of matured silkworm hemolymph were degraded to 3,000 Da by fermentation with B. amyloliquefaciens M27. Cell viability for MTT assay was higher than PBS in hemolymph and fermented hemolymph. A DPPH free radical scavenging activity of fermented hemolymph was as higher as Vitamin C and dependent on sample concentrations. Thus, these results suggest that degraded hemolymph fermented by B. amyloliquefaciens M27 may have antioxidant properties as a material for cosmetics.

• Korean journal of applied entomology
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• v.51 no.1
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• pp.47-58
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• 2012

Effect of a new crop protectant 'Bt-Plus' on natural enemies was analyzed in this study. Tested natural enemies included two parasitic species of $Aphidius$ $colemani$ and $Eretmocerus$ $eremicus$, and four predatory species of $Harmonia$ $axyridis$, $Orius$ $laevigatus$, $Amblyseius$ $swirskii$, and $Phytoseiulus$ $persimilis$. 'Bt-Plus' was formulated by combination of three entomopathogenic bacteria ($Xenorhabdus$ $nematophila$ (Xn), $Photorhabdus$ $temperata$ subsp. $temperata$ (Ptt), $Bacillus$ $thuringiensis$ (Bt)) and bacterial metabolite (BM). All three types of 'Bt-Plus' showed significantly higher toxicities against fourth instar $Plutella$ $xylostella$ larvae than Bt single treatment. Two types of bacterial mixtures ('Xn+Bt' and 'Ptt+Bt') showed little toxicity to all natural enemies in both contact and oral feeding assays. However, 'BM+Bt' showed significant toxicities especially to two predatory mites of $A.$ $swirskii$ and $P.$ $persimilis$. The acaricidal effects of different bacterial metabolites were evaluated against two spotted spider mite, $Tetranychus$ $urticae$. All six BM chemicals showed significant acaricidal effects. The BM mixture used to prepare 'Bt-Plus' showed a high acaricidal activity with a median lethal concentration at 218.7 ppm (95% confidence interval: 163.2 - 262.3). These toxic effects of bacterial metabolites were also proved by cytotoxicity test against Sf9 cells. Especially, benzylideneacetone, which was used as a main ingredient of 'BM+Bt', showed high cytotoxicity at its low micromolar concentration.

• Journal of Sericultural and Entomological Science
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• v.52 no.1
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• pp.39-44
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• 2014

We isolated highly-expressed genes in the posterior silk glands of silkworm on a previously study, which one of these was identified as RNA binding protein-1 homologue (RBP-1) gene. In this study, we investigated gene expressional characteristics of the RBP-1 depending on silkworm development stages and several tissues of the larvae, respectively. Northern blot hybridization analysis showed that the RBP-1 gene was expressed high in larval and pupal periods, and highly expressed than endogenous internal control gene (BmA3) on all tested larval tissues. In addition, we isolated and analyzed a phage DNA having 1,660 bp-long promoter region of the RBP-1 gene from a genomic DNA library. To study the RBP-1 gene promoter activity, RBP-1 (-740/+ 30) was amplified by PCR and subcloned into a pGL3 basic vector to generate pGL-RBP1. A luciferase report vector carrying RBP-1 gene promoter (770 bp) was tested by luciferase assay in Sf9 cells. In the result, the RBP-1 gene promoter was more efficient than constitutive promoter (BmA3) by approximately ten percent.

• Journal of Applied Biological Chemistry
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• v.55 no.2
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• pp.123-127
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• 2012

In order to develop eco-friendly biopesticide, an entomopathogenic bacterium Photorhabdus temperata M1021 has been lyophilized via freeze-drying along with protective agents such as skim milk, starch, sodium alginate, glucose and sodium glutamate to protect cells from lysis. Freeze-drying powder of P. temperata M1021 containing 7% skim milk (w/v) showed highest survival rate of 63% among all the protective agents used in trials. Furthermore, the freeze-dried microbial powder showed 75% of survival rate after stored at $4^{\circ}C$ for 4 weeks at air contact conditions. Injection toxicity of the freeze-dried sample was tested against larvae of Galleria mellonella. A dose of $2.0{\times}10^1$ cells of P. temperata M1021 killed 100% of the G. mellonella larvae within 4 days after injection. Moreover, $2.0{\times}10^0$ cells caused 50% mortality within the 4 days after injection. Freeze-dried P. temperata M1021 strains exhibited effective insecticidal activity and could be a better candidate for being used as a biopesticide.

• Journal of Sericultural and Entomological Science
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• v.43 no.2
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• pp.77-82
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• 2001

This study was investigated to know the effects of diflubenzuron(DFB) on the larval silkgland development of the silk-worm, Bombyx mori (L.). It has been known as a prohibitor of chitin synthesis mostly on the species of the Order Lepidoptera. In this work, the effects of the DFB concentrations (2.5$\times$10$\^$-1/,2.5$\times$10$\^$-2/, and 2.5$\times$10$\^$-3/$\mu\textrm{g}$/$\mu$l on the various larval stages, were investigated in terms on the silkgland. The macro- and microstructure of cell membrane of silkgland, and the differences of silkgland weight and water contents treated by DFB are also surveyed. As the tesults, the silkgland weight depended sensitively on not the DFB concentration but the DFB treatment period. The longer DFB treatment period, the lighter dried silkgland weight and the heavier water content of the silkgland. White opaque(WO) emerged in the middle silkgland of DFB treated larva. From the scanning election microscope observation, the cell membrane of silkgland of DFB treated larva was distinctly more compact compared to that of control. The WO was evidently resulted from the obstacles of normal transformation of silk protein through the cell membrane of middle silkgland.

• Journal of Sericultural and Entomological Science
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• v.52 no.1
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• pp.6-9
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• 2014

This study was for the investigation of the stability of purified bee venom (PBV) during the treatment in the pH range from pH2 to pH9 for 24 hours, respectively. Changes of components and physiological functionalities in PBV were by evaluated silver staining, and melittin contents were measured by liquid chromatography. The antimicrobial activity against bacteria by minimum inhibitory concentration (MIC) and effect of the cell regeneration were measured by 3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl tetrazolium bromide (MTT) assay using human dermal fibroblast (HDF) cell. The main proteins such as melittin and phospholipase $A_2$ showed no characteristic changes. The antimicrobial activity and effect of cell regeneration showed no difference from pH2 to pH9. From this study, we suggest that components and physiological functionalities of PBV against treated pH were kept stability at from pH2 to pH9.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.533-536
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• 2019

Recombinant baculoviruses are widely used to express heterologous genes in cultured insect cells. Recombinant baculoviruses can serve as gene-transfer vectors for expression of recombinant proteins in a wide range of mammalian cell types. Baculovirus system has significant benefits in view of safety, large-scale, and high level of gene expression. In this study, baculoviral vectors which were reconstructed from pOPINEneo-3C-GFP vector, were recombined with cytomegalovirus (CMV) promoter, green fluorescent protein (GFP), and p53 with NcoI and XhoI. These recombinant vectors were infected with various cells and cell lines. The baculovirus vector thus developed was analyzed by comparing the metastasis and expression of the recombinant genes with conventional vectors. These results suggest that the baculovirus vector has higher efficiency in metastasis and expression than the control vector. This work was supported by a grant from Mid-Career Researcher Program(NRF-2016R1A2B4016552) through the National Research Foundation of Korea(NRF) funded by the Ministry of Science, ICT & Future Planning(MSIP).

• Journal of Sericultural and Entomological Science
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• v.37 no.1
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• pp.46-51
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• 1995

In order to develope baculovirus expression vector system, we constructed new transfer vector of nuclear polyhedrosis virus of the silkworm, Bombyx mori. The promoter region containing only adenine of translation start codon of polyhedrin gene was cloned by polymerase chain reaction technique. And the 5' and 3' leader regions of polyhedrin gene was sequentially cloned. The polyhedrin coding gene was deleted from the ＋2 to the ＋597 position. As the result, we constructed new transfer vector which has EcoRI, SacI and KpnI sites for the cloning sites of foreign gene. New transfer vector was named as pBmKSKl. Escherichia coli $\beta$-galactosidase gene as foreign gene was inserted into pBmKSKl, under the control of the polyhedrin promoter and expressed in B. mori cells. The result showed that the new transfer vector pBmKSK1 is functional.

• The Korean Journal of Mycology
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• v.29 no.1
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• pp.61-66
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• 2001

Entomopathogenic fungus of Cordyceps militaris is famous of its medicinal efficacies. An antitumor compound was purified from the n-hexane extract of artificially cultivated fruiting bodies of C. militaris and identified as ergosterol peroxide $(5{\alpha},\;8{\alpha}-epidioxy-24(R)-methylcholesta-6,22-dien-3{\beta}-o1,\; C_{28}H_{44}O_3)$ mainly by $^1H\;and\;^{13}C-NMR$ spectroscopic techniques. When the antitumor activity of ergosterol peroxide was measured against 3 tumor cell lines from Korean cancer patients, it showed the most strong activity against gastric cancer SNU-l cell line 3 days after treatment. The 50% inhibitory concentrations $(IC_{50})$ of ergosterol peroxide 6 days after treatment were $75.8{\mu}g/ml$ for human gastric SNU-1 tumor cell line, $39.7{\mu}g/ml$ for human colorectal SNU-C4 tumor cell line and $32.7{\mu}g/ml$ for human hepatoma SNU-354 cell line.