• Parasites, Hosts and Diseases
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• v.32 no.4
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• pp.249-258
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• 1994

Recently, the importance of toxoplasmosis is raised as a complication in immunosuppressed or AIDS patients. Our study focused on the identification of a variety of Toxoplasma antigens by immunoblotting. Rabbits and BALB/c mice were immunized with Toxoplosmo Iysate (RH strain) , frozen tachyzoites (RH strain) or cysts (Beverly and Fukaya strain) . Blood were collected from ear vein, heart or orbital plexus for detecting the serum antibody levels. For excretory-secretory (E.S) antigens, T gondii (RH) tachyzoite were cultured in CHL (Chinese hamster lung) cells with MEM containing of 5% FCS. After 72hrs, culture supernatant was collected. BALB/c mice were inoculated with RH tachyzoite intraperitoneally and peritoneal fluids were extracted three days later. E.S antigens were detected in culture supernatant and infected mouse peritoneal fluid by EITB. Serum IgG levels in rabbit were 1 :512 of 10 days after primary immunization, 1 : 2,048 of 10 days after secondary immunization, 1: 1,024 of 20 days after secondary immunization by IFAT, respectively. Serum IgG levels of immunized mice were 1:128 after 7 weeks. Tachyzoite antigens of the RH strain were detected 25 protein bands ranging 10 kDa-220 kDa of molecular weights with Coomassie blue stain. Toxoplcsma major antigens corresponding to n of 24 kDa, 27 kDa,30 kDa, 35 kDa, 38 kDa were recognized by IgG and IgM antibodies. Excretory-secretory antigens present in culture supernatant with M. W. of 20, 30 kDa and in infected mouse peritoneal fluid with M.W. of 33 (P30), 45 kDa. When RH tachyzoite antigen was probed with different mice sera immunized with 2 strains of T gondii, the IgG antibody bud of Fukaya and Beverly strain (8 week-serum) is identical to those of RH strain. It is considered that the 30 kDa polypeptide detected in excretory- secretory materials and Iysate was important major antigen of T gondii (RH).

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.271-279
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• 2015

Lactoferrin (LF) is a multifunctional, iron-binding glycoprotein found in physiological secretions of mammals. LF shows antibacterial, antiviral and antifungal activities. In the present study, a gene encoding the N-terminal lobe of human lactoferrin (hLF) was isolated, cloned and expressed in methylotrophic yeast, Pichia pastoris. The recombinant hLF-N (rhLF-N) protein was secreted into the culture medium at the level of $458{\mu}g/ml$ in 3 L fermentor. The size of purified hLF-N was estimated as 35 kDa when analyzed by SDS-PAGE and western blotting. The rhLF-N was further confirmed by immunodiffusion using the anti-hLF polyclonal antibody. The expression profile analysis by qRT-PCR showed that the relative mRNA expression of rhLF-N was maximal after 2-3 days of methanol induction and reduced gradually at 4 days. The purified rhLF-N showed broad antibacterial activities against the pathogens such as Staphylococcus aureus, E. coli, Pseudomonas aeruginosa, Burkholderia cepacia, and Salmonella typhimurium. However, rhLF-N showed relatively lower activity when compared to peptides derived from LF. In spite of this weak activity, the rhLF-N expressed in P. pastoris might be more advantageous for the industrial application, because rhLF-N is secreted into the culture medium and the production can also be increased by optimization of culture conditions.

• Journal of the Korean Magnetic Resonance Society
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• v.20 no.4
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• pp.138-142
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• 2016

Replication Protein A (RPA) is the eukaryotic single-stranded DNA binding protein. It involves in DNA replication, repair, and damage response. Among three subunits, RPA70 has a protein-protein binding domain (RPA70N) at the N-terminal. It has known that the domain recruits several damage response proteins to the damaged site. Also, it is suggested that there are more candidates that interact with RPA70N. Even though several studies performed on the structural aspects of RPA70N and its ligand binding, the backbone assignments of RPA70N is not available in public. In this study, we present the backbone assignments of RPA70N.

• BMB Reports
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• v.40 no.5
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• pp.825-831
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• 2007

Tumor cell invasion and metastasis are often associated with matrix metalloproteinases (MMPs), among which MMP-2 and MMP-9 are of central importance. We previously showed that H-Ras, but not N-Ras, induced invasion of MCF10A human breast epithelial cells in which the enhanced expression of MMP-2 was involved. MMP-2 is produced as a latent pro-MMP-2 (72 kDa) to be activated resulting the 62 kDa active MMP-2. The present study investigated if H-Ras and/or N-Ras induces pro-MMP-2 activation of MCF10A cells when cultured in two-dimensional gel of type I collagen. Type I collagen induced activation of pro-MMP-2 only in H-Ras MCF10A cells but not in N-Ras MCF10A cells. Induction of active MMP-2 by type I collagen was suppressed by blocking integrin ${\alpha}2$, indicating the involvement of integrin signaling in pro-MMP-2 activation. Membrane-type (MT)1-MMP and tissue inhibitor of metalloproteinase (TIMP)-2 were up-regulated by H-Ras but not by N-Ras in the type I collagen-coated gel, suggesting that H-Ras-specific up-regulation of MT1-MMP and TIMP-2 may lead to the activation of pro-MMP-2. Since acquisition of pro-MMP-2 activation can be associated with increased malignant progression, these results may help understanding the mechanisms for the cell surface matrix-degrading potential which will be crucial to the prognosis and therapy of breast cancer metastasis.

• Microbiology and Biotechnology Letters
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• v.29 no.3
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• pp.155-161
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• 2001

A bactriocin produced by Lactrococcus sp. HY449 was purified by sequential purfication steps such as n-propanol-acetone precipitation ion -exchange chromatography using CM-Sequential CL6B. gel filtration chromatography using Sephacry HR100 and reverse-phase chromatography using pro RPC HR 5/10. Reverse-phase chromatography the final step of the purfication yielded a single symmetrical peak of bacteriocin activity The purification resulted in final yield of 3.25% and 413.35 fold increase of the specific activity of bacteriocin. The active fraction from reverse-phase chromatography was used for N-terminal amino acid analysis . The purified bacteriocin contained isoleucine, leucine, methionine, and glycine at but N-terminal end no aromatic amino acids. Calculation of the number of amino acid residues in the bacteriocin revealed that it is consisted of 32 residues assuming the molecular weight of bacteriocin to be about 3.6kDa. Edman degrandation elucidated amino acid residues of the first four of the N-terminus to be $NH_2$-Ile-Leu-Pro-GIn.

• Journal of Microbiology and Biotechnology
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• v.24 no.12
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• pp.1719-1727
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• 2014

In the present study, whispovirus immediate early 1 promoter (ie-1) was used to initiate surface expression of the hemagglutinin (HA) protein of Egyptian H5N1 avian influenza virus (AIV) by using the baculovirus expression vector system. The HA gene and whispovirus ie-1 promoter sequence were synthesized as a fused expression cassette (ie1-HA) and successfully cloned into the pFastBac-1 transfer vector. The recombinant vector was transformed into DH10Bac competent cells, and the recombinant bacmid was generated via site-specific transposition. The recombinant bacmid was used for transfection of Spodoptera frugiperda (Sf-9) insect cells to construct the recombinant baculovirus and to induce expression of the HA protein of H5N1 AIV. The recombinant glycoprotein expressed in Sf-9 cells showed hemadsorption activity. Hemagglutination activity was also detected in both extra- and intracellular recombinant HAs. Both the HA and hemadsorption activities were inhibited by reference polyclonal anti-H5 sera. Significant expression of the recombinant protein was observed on the surface of infected insect cells by using immunofluorescence. SDS-PAGE analysis of the expressed protein revealed the presence of a visually distinguishable band of ~63 kDa in size, which was absent in the non-infected cell control. Western blot analysis confirmed that the distinct 63 kDa band corresponded to the recombinant HA glycoprotein of H5N1 AIV. This study reports the successful expression of the HA protein of H5N1 AIV. The expressed protein was displayed on the plasma membrane of infected insect cells under the control of whispovirus ie-1 promoter by using the baculovirus expression vector system.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.10-12
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• 2002

사용자의 요구와 인터넷 어플리케이션의 발달로 규모가 큰 미디어 오브젝트의 수가 급증하고 있다. 따라서 네트워크 전송비용은 반드시 고려해야 하는 중요한 요소이다. 본 논문에서는 기존 프락시 캐시 교체 정책들을 분석하고, 이를 개선한 G-N 및 L-N 정책을 제안한다. 이것은 프락시 캐시 소프트웨어인 'Squid'에서 채택하고있는 GDSF와 LFU-DA 정책에 네트워크 전송 비용을 추가하여 확장한 알고리즘이다. 시뮬레이션을 통하여 기존의 알고리즘과 비교해 본 결과, 평균 응답 시간을 10%이상 감소시킬 수 있었으며, 추가로 드는 비용(Processing Overhead)은 3게 증가하지 아니 하였음을 확인하였다.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.821-824
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• 1999

In distributed arithmetic-based architecture for an inner product between two length-N vectors, the size of the ROM increases exponentially with N. Moreover, the ROMs are generally the bottleneck of speed, especially when their sire is large. In this paper, a ROM size reduction technique for DA (Distributed Arithmetic) is proposed. The proposed method is based on modified OBC (Offset Binary Coding) and control circuit reduction technique. By simulations, it is shown that the use of the proposed technique can result in reduction in the number of gates up to 50%.

• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.1075-1078
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• 2008

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.196.2-197
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• 2003

Parkinson's disease (PO) is a widespread neurodegenerative disorder. Even though PD has been studied in many aspects, it is still unknown the molecular signaling mechanisms linking reactive oxygen species (ROS) and neuronal apoptosis in PD. A better understanding of cellular mechanisms that occur in Parkinson's disease is essential for development of new therapies. In this study we investigated the signaling molecules involved in neuronal apoptosis induced by 6-hydroxydopamine (6-OHDA) in human SK-N-SH neuroblastoma cells as a model cellular system. (omitted)