• BMB Reports
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• v.41 no.2
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• pp.93-101
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• 2008

The major cell wall components of bacteria are lipopolysaccharide, peptidoglycan, and teichoic acid. These molecules are known to trigger strong innate immune responses in the host. The molecular mechanisms by which the host recognizes the peptidoglycan of Gram-positive bacteria and amplifies this peptidoglycan recognition signals to mount an immune response remain largely unclear. Recent, elegant genetic and biochemical studies are revealing details of the molecular recognition mechanism and the signalling pathways triggered by bacterial peptidoglycan. Here we review recent progress in elucidating the molecular details of peptidoglycan recognition and its signalling pathways in insects. We also attempt to evaluate the importance of this issue for understanding innate immunity.

• The Korean Journal of Zoology
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• v.38 no.3
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• pp.313-323
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• 1995

Ultrastructural characteristics of hemocytic differentiation pathway in Sericinus montetla Grey were observed with transmission electron microscope. Hemocytic differentiation took place in loose islets of hemopoietic organs as indicated by the presence of differentiating hemocytes; prohemocytes, plasmatocytes, granular cells and spherule cells. They are differentiatied from the stem cells through individual cell lineages. However, differentiating aspects of the oenocytoids were not observed. According to Brehelin and Zachary (1986), the premature hemocytes around the hemopoietic organs were classified into five types; prohemocytes, plasmatocytes, granular cells, spherule cells and oenocytoids.

• Journal of Sericultural and Entomological Science
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• v.38 no.1
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• pp.53-56
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• 1996

To investigate the molecular biological marker in insect cells, BmN-4 and Sf-0 cells were analysed by SDS-PAGE and random amplification of polymorphic DNA. The results showed that the patterns of total cell protein and random amplification of polymorphic DNA were distinguished between BmN-4 and Sf-9 cells, suggesting that the unique major bands were useful as molecular biological marker in BmN-4 and Sf-9 cells.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.331-338
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• 2014

Cystatins (CSTs) are reversible and competitive inhibitors of C1A cysteine proteases, corresponding to papain-like cathepsins in plants and animals. A viral CST (CpBV-CST1) was identified from a polydnavirus, Cotesia plutellae bracovirus (CpBV). Our previous study indicated that a transient expression of CpBV-CST1 interfered with immune response and development of Plutella xylostella larvae. To directly demonstrate the protein function, this study produced a recombinant CpBV-CST1 protein (rCpBV-CST1) using bacterial expression system to determine its inhibitory activity against cysteine protease and to assess its physiological alteration in insect immune and development. The open reading frame of CpBV-CST1 encodes a polypeptide of 138 amino acids (${\approx}15kDa$). rCpBV-cystatin protein in BL21 STAR (DE3) competent cells containing a recombinant pGEX4T-3:CpBV-CST1 was over-expressed by 0.5 mM IPTG for 4 h. In biological activity assay, the purified rCpBV-CST1 showed a significant inhibition against papain activity. It inhibited a cellular immune response of hemocyte nodule formation in the beet armyworm, Spodoptera exigua. Moreover, its oral administration retarded larval development of the diamondback moth, Plutella xylostella in a dose-dependent manner. These results suggest that CpBV-CST1 may be applied to control insect pest populations.

• Food Science and Preservation
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• v.13 no.4
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• pp.513-518
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• 2006

Insect resources have been widely recognized that seven millions of insects exhibit it own biological activity by whole body or its metabolic intermediates. In order to investigate antioxidant activity and compare the cyclooxygenase-2 promoter activity from insect extract, we tested in vitro antioxidant assays and cyclooxygenase-2 promoter assay in Coccinella septempunctata Linne and Harmonia axyridis extracts have the anti-oxidant and cyclooxygenase-2 inhibition activities, we examined the anti-oxidant assays including DPPH, FRAP and linoleic acid, ana inhibition of cyclooxygenase-2 expression using a cyclooxygenase-2 promoter-inserted stable cell line. We found that Harmonia axyridis Pallas extract had potentials to anti-oxidant activity and inhibited about 25% of cyclooxygenase-2 transcription activity. These findings indicate that Coccinella septempunctata Linne and Harmonia axyridis Pallas extracts could be an useful insect resource for agrobiotechnological purposes.

• Journal of Applied Biological Chemistry
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• v.60 no.3
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• pp.271-277
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• 2017

Ethyl formate has been used for the control of insect pests by fumigation. However, there were not many reports to show its target site of fumigant toxicity on insect pests since its first use in the agricultural industry. In the present study, we showed the presumable target sites of ethyl formate fumigation in insect pests using Myzus persicae nymphs. After ethyl formate fumigation, the nymphs of this species were collected and the changes at the biochemical and molecular level were determined. The activity of cytochrome c oxidase (COX) was approximately two-fold higher after ethyl formate fumigation. In addition, the expression levels of acetylcholinesterase (AChE) decreased gradually with increasing ethyl formate concentration. These two findings suggested that COX and AChE might be the major target sites of ethyl formate fumigation. In addition to these results, the analysis of lipid content using MALDI-TOF MS/MS identified 9 phospholipids differently generated 2-fold higher in the ethyl formate-treated nymphs than that in the control nymphs, thereby leading to changes in cell membrane composition in M. persicae nymphs. Therefore, the ethyl formate fumigation caused lethal effects on M. persicae nymphs by changing COX activity, AChE gene expression, and phospholipid production.

• Korean journal of applied entomology
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• v.57 no.1
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• pp.7-13
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• 2018

Currently, there is no available tool that rapidly diagnoses pine wood nematode (PWN)-infected pine trees in the field. In this study, we synthesized and purified PWN Galectin, which might be an antigen specific to PWN, using the Baculovirus expression system. We used PWN Galectin as an antigen for generating 1,464 fusion hybridoma cell lines secreting monoclonal antibodies (Mabs). Among them, we selected 62 fusion hybridoma cell lines showing high reactivity to PWN Galectin. We further selected 12 fusion hybridoma cell lines showing high reactivity to the standard PWN-infected pine tree phosphate buffered saline (PBS) extract. Additionally, two fusion hybridoma cell lines showing no or extremely low reactivity were used as controls. The selected fusion hybridoma cell lines were subjected to limiting dilutions for selecting and establishing Mab-secreting cell lines showing higher reactivity to the standard PWN-infected pine tree extract than to the standard normal pine tree PBS extract. Moreover, the selected fusion hybridoma cell lines were further selected based on their higher reactivity to PWN protein extracts than to three non-pathogenic nematode protein extracts. The Mab-secreting cell lines established in this study could be used to develop rapid diagnostic tools that can be used in the field or in laboratories for detecting PWN-infected pine trees or PWN.

• Journal of Sericultural and Entomological Science
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• v.53 no.2
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• pp.92-96
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• 2015

It is known that silk protein supports effectively proliferation of cell such as insect cell and hybridoma cell. Although there are many varieties of Bombyx mori silkworm, the effect of silkworm varieties on cell proliferation has not been considered in detail. We studied that characteristics of silk cocoon obtained from Baegokjam, Kumokjam, Daeseongjam silkworm varieties and whether silk protein affected cell proliferation or not. Silk sericin was prepared under high temperature and high pressure condition. Silk fibroin was prepared using $CaCl_2:H_2O:EtOH$ with different dissolution time. As a result, there are differences in silk cocoon from different silkworm varieties about cell proliferation. The proliferation was accelerated in the presence of Baegokjam silk sericin and Kumokjam silk fibroin with 5hr dissolution time. We expect that silk proteins could be a preferable culture medium supplement for stimulating the proliferation of cell. Then, this results suggest silk as a new material for medium supplement replacing with fetal bovine serum.

• Applied Microscopy
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• v.18 no.2
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• pp.102-118
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• 1988

This study was carried out to examine in vitro first whether the storage proteins, which the fat bodies of last larvae from Hyphantria cunea secrete into haemolymph, can be uptaked by the fat body cells of prepupa and then how the uptaked storage proteins can be accumulated in the fat body cells, if uptaken. The fat bodies which had been isolated from last instar larvae were cultured in 1 ml of Grace's insect medium containing $50{\mu}l$ of $^{3}H$-leucine (5.0 mCi/mol, Dupont) at $28{\pm}2^{\circ}C$ for 6 hrs. After the homogenates of the cultured fat bodies were centrifuged at 10,000 rpm for 10 minutes, the proteins included in the supernatant were separated by polyacrylamide gel electrophoreses (non-SDS, 6%). The next treatment of the electrophoresed gel was followed by rinsing. A storage protein band of several bands in the rinsed gel was sliced off. With elution of sliced storage protein bands in Tris-glycine buffer, the purification of radioactive storage proteins from fat bodies was finished. After the purified radioactive storage proteins were added in Grace's insect midis containing fat bodies of the prepupae, they were cultured for the randomly following minutes given as 3, 5, 7, 10, 15, 20 and 30 and for the randomly following hours given as 1, 2, 3 and 4 respectively. The double fixations of the cultured fat bodies in aldehyde and $OsO_4$, were followed by preparation of ultrathin sections from Epon-Araldite blocks through dehydration and embedding. The electron microscope autoradiographic treatment of all prepared sections were performed by the dipping method (Kim et al., 1987). The finally prepared specimens were examined with electron microscope. The fat body cells of the prepupa could be found to uptake the storage preteins of the last instar larvae, which were included in the culture medium, mostly by formation of coated vesicles. The in vitro uptake of the storage proteins actively occurred by 30 minutes after the addition of purified storage proteins in the culture medium. After culture for 7 minutes with the storage proteins, the uptaked radioactive storage proteins labelled a number of lysosomal granules. After culture for 20 minutes with the storage proteins, the radioactive storage proteins were finally incorporated and accumulated in lipid droplets and protein granules. The frequency in the fat body cell of radiolabelled lipid droplets occurs approximately 60%, while the frequency, in which the radiolabelled protein granules occurs in a fat body cell, is approximately 40%.

• KSBB Journal
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• v.15 no.1
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• pp.100-105
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• 2000

Optimal medium composition, culture conditions, characteristics of phase variation and activity of insecticidal toxin by Xenorhabdus nematophilus isolated and identified from Korean entomopathogenic nematode Steinernema carpocapsae were examined. Optimal medium composition of this strain was 50-70 g/L yeast extract, 3 g/L $K_{2}HPO_{4}$, 1g/L $NH_{4}H_{2}PO_{4}$, 2g/L ${MgSO}_4$$\cdot$${7H}_{2}O$, 10g/L NaCl and, these, yeast extract was found as a limiting nutrient for cell growth. When Monod equation was applied, maxmum specific growth rate and Monod constant were estimated as 0.13 $hr^{-1}$ and 20g/L, respectively. The pH of culture medium increased up to 8.5-9.5 regardless of initial pH 6-7 as the cells continued to grow. The specific growth rate in a 7 L fermentor was 0.18 $hr^{-1}$, which was enhancement 1.4 fold compared to a flask culture. In case of phase variation, phase I fraction was maintained above 90% at the stationary phase for both flask and fermentor cultures. According to oral toxicity test of Gallena mellonella by Xenorhabdus nematophilus, the addition of cell pellets into feed inhibited normal growth of insect larvae and killed completely then after 20 days cultivation. When culture supernatant of this strain was injected into hemolymph of insect larva, the toxicity was strongest at 24hr cultivation in the early exponential phase and gradually decreased as the culture time proceeded.