• 한국미생물·생명공학회지
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• 제21권5호
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• pp.504-510
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• 1993

The effect of AcNPV infection conditions such as serum concentration, pH, CaCl2, lysosomotropic agent, cell density at infection, agitation, aeration and nutritional supplementattion on recombinant protein production in Spodoptera frugiperda 21 cells was investigated using tissue culture flask, bottle and spinner flask. It was shown that serum, CaCl2, pH and cell density at infection affected recombinant production. The lysosomotropic agent did not significantly influence recombinant protein production.

• Journal of Microbiology and Biotechnology
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• 제9권3호
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• pp.361-364
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• 1999

The binding characteristics of Anagrapha falcifera nuclear polyhedrosis virus (AtNPV) to Spodoptera frugiperda 21 (Sf21) cells were investigated. The cells displayed an affinity of 4.7×10/sup 10/M/sup -1/ with about 3,300 binding sites per cell. The biochemical nature of the AfNPV-binding sites on the cell surface was also partially identified. Our findings suggest that the binding-site moiety has a glycoprotein component, but that the direct involvement of oligosacccharides containing N-acetylglucosamine or sialic acid residues in binding is unlikely, and that AfNPV entry into Sf21 cells may be via receptor-mediated endocytosis.

• 한국잠사곤충학회지
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• 제38권1호
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• pp.53-56
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• 1996

곤충세포주로 널리 이용되고 있는 Sf 세포주와 Bm 세포주의 분자생물학적 표식자를 탐색하기 위하여, 총 세포 단백질의 SDS-PAGE와 genomic DNA를 RAPD(Random Amplification of Polymorphic DNA) 방법으로 분석하였다. 그 결과, 총 세포 단백질 및 genomic DNA, 패턴에서 두 세포주를 뚜렷하게 구별할 수 있는 밴드를 탐색하였으며, 이들은 유용한 분자 생물학적 표식자로 이용될 수 있을 것이다.

• Journal of Microbiology and Biotechnology
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• 제4권3호
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• pp.200-203
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• 1994

Spodoptera frugiperda IPLB-SF-21-AE cells were cultivated in a spin-filter bioreactor with continuous perfusion for the recombinant $\beta$-galactosidase production. At the perfusion rate of 0.06 $hr^{-1}$, the maximum cell density of insect cells in this bioreactor system reached 3.5$\times$$l0^6$ viable cells/ml using the Grace media containing 5% FBS and 0.3% Pluronic F-68. The recombinant $\beta$-galactosidase production of 8, 100 units per reactor volume was also achieved at this perfusion rate.

• 한국미생물·생명공학회지
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• 제18권6호
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• pp.660-661
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• 1990

Autographa californica nuclear polyhedrosis virus(AcNPV) L-1주의 extracellular nonoccluded virion (NOV)을 보관하는 방법을 연구하였다. AcNPV NOVs을 Spodoptera frugiperda cell line에 감염을 시킨 후에 배양액을 원심분리하여 AcNPV NOVs가 들어 있는 상등액을 취하여 $4^{\circ}C$에서 약 11년간 보관하였다. 보관되어 있는 AcNPV NOV을 Spodoptera frugiprda cell line에 재감염하여 관찰한 결과 NOVs의 감염과 증식이 정상적이었으며, NOV의 역가가 $8.9 \times 10^7$pfu/ml에서 $3.8 \times 10^5$pfu/ml로 떨어졌을 뿐이다. 또한 HindIII와 EcoRI 제한효소로 AcNPV genome DNA을 절단하여 패턴을 조사한 결과 DNA제한 효소 패턴은 변하지 않았다. 즉 AcNPV NOVs는 $4^{\circ}C$에서 보존하면 10년 이상 안정성이 있고, 취급이 용이하다는 것을 알 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제4권3호
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• pp.183-190
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• 1994

Cell-free extracts prepared from cultured insect cells, Spodoptera. frugiperda, were analyzed for activation of early gene transcription of an insect baculovirus, Autographa californica nuclear polyhedrosis virus (AcNPV). The template DNA used for in vitro transcription assays contained promoter sites for the baculovirus genes that have been classified as immediate early ($\alpha$) or early genes. These genes are located in the HindIII-K/Q region of the AcNPV genome. Nuclei isolated from the AcNPV-infected Spodoptera frugiperda cells were also used for in vitro transcription analysis by RNase-mapping the labeled RNA synthesized from in vitro run-on reaction in the isolated nuclei. The genes studied by this technique were p26 and pl0 genes which were classified as delayed early and late gene, respectively. We found that transcription of the genes from the HindIII-K region was accurately initiated and unique in the whole cell extract obtained from uninfected cells, although abundance of the in vitro transcripts was reverse to that of in vivo RNA. With isolated nuclei transcription of the p26 gene was inhibited by $\alpha$-amanitin suggesting that the p26 gene was transcribed by host RNA polymerase II. However, transcription of the pl0 gene in isolated nuclei was not inhibited by $\alpha$-amanitin, but rather stimulated by the inhibitor. We also found that the synthesis of $\alpha$-amanitin-resistant RNA polymerase was begun before 6 hr p.i., the time point at which the onset of viral DNA replication as well as the appearance of a-amanitin-resistant viral transcripts were detected. These studies give us strong evidence to support the previous data that early genes of AcNPV were transcribed by host RNA polymerease III, while transcription of late genes was mediated at least by a novel $\alpha$-amanitin-resistant RNA polymerase.

• Applied Microscopy
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• 제11권1호
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• pp.51-57
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• 1981

Autographa californica Nuclear Polyhedrosis Virus의 Nucleocapsids의 형성과 Polyhedra Occlusion Bodies의 형성을 Spodoptera frugiperda 세포에 감염된 후 3 일째 된 것을 관찰하였다. 1. A. californica NPV는 Spodoptera 세포의 핵내에서 분열복제되어 Nucleocapsid를 형성하여, 외투막을 얻은 후에 Polyhedra Occlusion Bodies 로 함입 되었다. 2. A. californica NPV가 감염된 세포의 핵은 팽창되어 핵막이 세포질까지 거의 신장되어 있었다. 3. Polyhedra Occlusion Bodies의 형성은 NPV로 감염된 세포에서 작은 엉성한 단백질 또는 Polypeptides가 점진적으로 커지면서 바이리스들이 함입되면서 더욱 덩치가 커지게 되고, 세포질내에 NPV 바이러스들이 없어지면 Polyhedra는 외부에 매끈한 막을 형성하는 것이 관찰되었다. 4. Polyhedra Occlusion Bodies의 형태는 바이러스 다발이 함입되어 있는 상태에 따라서 다양하였다. 5. Polyhedra 에 있는 바이러스 다발들은 외투막을 가지며 바이러스사이에도 기저물질이 존재하는 것을 볼 수 있었다.

• 대한의생명과학회지
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• 제11권1호
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• pp.57-61
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• 2005

The number of sites at which a protein can be readily cleaved by a proteolytic enzyme is greatly influenced by its three-dimensional structure. For native, properly-folded proteins both the rate of cleavage and number of sites at which cleavage takes place are usually much less than for the denatured protein. In order to compare the tertiary structure of recombinant HepG2 type glucose transporter with that of its native counterpart in the erythrocyte, the pattern of tryptic cleavage of the protein expressed in insect cell membranes was therefore examined. After 30 minutes digestion, a fragment of approximate Mr 19,000-21,000 was generated. In addition to this, there were two less intensely stained fragments of apparent Mr 28,000 and 17,000. The pattern of labelling was similar up to 2 hours of digestion. However, the fragments of Mr 19,000-21,000 and Mr 17,000 were no longer detectable after 4 hours digestion. The observation of a very similar pattern of fragments yielded by tryptic digestion of the HepG2 type transporter expressed in insect cells suggests that the recombinant protein exhibits a tertiary structure similar if not identical to that of its human counterpart. Also, the endogenous sugar transporter(s) present in Sf21 cells did not bind cytochalasin B, the potent transporter inhibitor. Therefore, the baculovirus/Spodoptera frugiperda (Sf) cell expression system could be very useful for production of large amounts of human glucose transporters, heterologously.

• 대한의생명과학회지
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• 제11권4호
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• pp.487-492
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• 2005

The baculovirus/insect cell expression system is of great value in the study of structure-function relationships in mammalian glucose-transport proteins by site-directed mutagenesis and for the large-scale production of these proteins for mechanistic and biochemical studies. Spodoptera frugiperda Clone 21 (Sf2l) cells grow well on TC-100 medium that contains $0.1\%$ D-glucose as the major carbon source, strongly suggesting the presence of endogenous glucose transporters. However, very little is known about the properties of the endogenous sugar transporter(s) in Sf2l cells, although a saturable transport system for hexose uptake has been previously revealed in the Sf cells. In order to further examine the substrate and inhibitor recognition properties of the Sf2l cell transporter, the ability of hexoses to inhibit 2-deoxy-D-glucose (2dGlc) transport was investigated by measuring inhibition constants $(K_i)$. The $K_i's$ for reversible inhibitors were determined from plots of uptake versus inhibitor concentration. Transport was effectively inhibited by D-mannose and D-glucose. Of the hexoses tested, L-glucose had the least effect on 2dGlc transport in the Sf2l cells, indicating that the transport is stereoselective. Unlike the human HepG2 type glucose transport system, D-mannose had a somewhat greater affinity for the Sf2l cell transporter than D-glucose, implying that the hydroxyl group at the C-2 position is not necessary for strong binding. However, epimerization at the C-4 position of D-glucose (D-galactose) resulted in a dramatic decrease in affinity of the hexose for the Sf2l cell transporter. Such a lowering of affinity might be the result of the involvement of the C-4 hydroxyl in hydrogen bonding. It is therefore suggested that Sf2l cells were found to contain an endogenous sugar transport activity that in several aspects resembles the human HepG2 type glucose transporter, although the insect and human transporters do differ in their affinity for cytochalasin B.

• 대한의생명과학회지
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• 제12권1호
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• pp.17-22
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• 2006

The baculovirus expression system is a powerful method for producing large amounts of the human erythrocyte-type glucose transport protein, heterologously. Characterization of the expressed protein is expected to show its ability to transport sugars directly. To achieve this, it is a prerequisite to know the properties of the endogenous sugar transport system in Spodoptera frugiperda Clone 21 (Sf21) cells, which are commonly employed as a host permissive cell line to support the baculovirus replication. The Sf21 cells can grow well on TC-100 medium that contains 0.1% D-glucose as the major carbon source, strongly suggesting the presence of endogenous glucose transport system. However, unlike the human glucose transport protein that has a broad substrate and inhibitor specificity, very little is known about the nature of the endogenous sugar transport system in Sf21 cells. In order to characterize further the inhibitor recognition properties of the Sf21 cell transporter, the ability of phloretin, cytochalasin B and D-fructose to inhibit 2-deoxy-D-glucose (2dGlc) transport was examined by measuring inhibition constants $(K_i)$. The $K_i's$ for reversible inhibitors were determined from plots of uptake versus inhibitor concentration. The 2dGlc transport in the Sf21 cells was very potently inhibited by phloretin, the aglucone of phlorizin with a $K_i$ similar to the value of about $2{\mu}M$ reported for inhibition of glucose transport in human erythrocytes. However, the Sf21 cell transport system was found to differ from the human transport protein in being much less sensitive to inhibition by cytochalasin B (apparent $K_i$ approximately $10\;{\mu}M$). In contrast, It is reported that the inhibitor binds the human erythrocyte counterpart with a $K_d$ of approximately $0.12\;{\mu}M$. Interestingly, the Sf21 glucose transport system also appeared to have high affinity for D-fructose with a $K_i$ of approximately 5mM, contrasting the reported $K_m$ of the human erythrocyte transport protein for the ketose of 1.5M.