• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.82-86
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• 1998

The maltose binding protein (MBP) fusion protein system is a versatile tool to express and isolate recombinant proteins in E. coli. In this system, MBP fusion proteins are efficiently isolated from whole cell lysate using amylose conjugated agarose beads and then eluted by competition with free maltose. Since MBP is a rather large molecule (∼42 kDa), for further experiments, the MBP part is usually proteolytically cleaved from the fusion protein and subsequently removed by ion-exchange chromatography or rebinding to amylose columns after washing out excess and MBP-bound maltose. In the present study, we have developed an improved method for the removal of cleaved MBP, which is advantageous over conventional methods. In this method, factor Xa cleaved MBP fusion proteins were incubated with Sepharose beads conjugated with MBP specific monoclonal antibodies and then precipitated buy centrifugation, resulting in highly purified proteins in the supernatant.

• Parasites, Hosts and Diseases
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• v.54 no.4
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• pp.461-469
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• 2016

Giardia lamblia is a protozoan that causes diarrheal diseases in humans. Cytoskeletal structures of Giardia trophozoites must be finely reorganized during cell division. To identify Giardia proteins which interact with microtubules (MTs), Giardia lysates were incubated with in vitro-polymerized MTs and then precipitated by ultracentifugation. A hypothetical protein (GL50803_8405) was identified in the precipitated fraction with polymerized MTs and was named GlMBP1 (G. lamblia microtubule-binding protein 1). Interaction of GlMBP1 with MTs was confirmed by MT binding assays using recombinant GlMBP1 (rGlMBP1). In vivo expression of GlMBP1 was shown by a real-time PCR and western blot analysis using anti-rGlMBP1 antibodies. Transgenic G. lamblia trophozoites were constructed by integrating a chimeric gene encoding hemagglutinin (HA)-tagged GlMBP1 into a Giardia chromosome. Immunofluorescence assays of this transgenic G. lamblia, using anti-HA antibodies, revealed that GlMBP1 mainly localized at the basal bodies, axonemes, and median bodies of G. lamblia trophozoites. This result indicates that GlMBP1 is a component of the G. lamblia cytoskeleton.

• Toxicological Research
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• v.16 no.3
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• pp.221-227
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• 2000

A 6-sulfooxymethylbenzo[a]pyrene (SMBP), the ultimate metabolite of methyl-substituted benzo[a]pyrene (BP), has been found to be carcinogenic in mice. These properties may be attributable to its strong reactivity with cellular macromolecules such as DNA. However, serum and its major constituent albumin attenuated significantly the cytotoxicity and mutagenicity of 5MBP in bacterial and mammalian cell systems. This inhibitory activity of serum against 5MBP-induced cytotoxicity and mutagenicity in Chinese hamster V79 cells appears to be caused by the reduced macromolecular adducts such as DNA and proteins, but serum failed to reduce 5MBP binding to naked calf thymus DNA. A number of proteins in the serum could act as nucleophiles that are able to intercept reactive chemicals through covalent binding. Albumin present in the plasma seems to be one of major components responsible for direct binding with 5MBp, thereby reducing its reactivity to genetic materials. We here determined which fraction is preferential for 5MBP binding through fractionation of 5MBP-treated serum with ammonium sulfate. The albumin-containing fraction had slightly more affinity for 5MBP than the immunoglobulin-containing fraction. Our results indicate that the covalent modification of plasma proteins may reduce 5MBP-induced damage.

• The Korean Journal of Ecology
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• v.21 no.3
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• pp.225-231
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• 1998

The studies on the potentiality of biomonitoring heavy metal pollution in coastal region of industrial complex were performed to investigate the heavy metal accumulation and induction of metal-binding protein (MBP) as detoxification process using Rumex maritimus. Bioconcentration in organs and MBP in root of R. maritimus was investigated for the research of the tolerance of heavy metals. The bioconcentration of cadmium and zinc in organs showed 3.6-8.0 times in root higher than in shoot, so it was found that heavy metal accumulated selectively in root. MBP increased absorbance in 254 nm and decreased in 280 nm, because it was composed of high cystein content and low aromatic acids, so absorbance had large difference between 254 nm and 280 nm. The existence of MBP in the 10-20 fraction was ascertained with anion exchange chromatography and it was identified that concentration of heavy metal increased according as an exposure concentration of medium increased in QAE Sephadex A-25 elution profile. These results suggested that MBP could play a role in biomarker determining the bioconcentration of plant. This study demonstrated a possibility that removal ability of heavy metal of R. maritimus resulted from detoxification process and MBP could be utilized as a biomarker of heavy metal pollution.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.10 no.16
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• pp.53-61
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• 1987

This study is on the Management by Policy-Deployment(MBP) a Japanese-devised management system which recently call a widespread awareness and applications among major Korean Industries. The principal nature of MBP was compared with Management by Objectives(MBO) as these two systems share similarities in basic nature. Then the major application problems of MBP encountered by the practicing managers were encountered and examined In relation to the Japanese firms organizational culture.

• Journal of Life Science
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• v.25 no.4
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• pp.385-389
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• 2015

In this study, it is reported that a large polyprotein can be stoichiometrically cleaved by the use of caspase-3-dependent proteolysis. Previously, it has been shown that the proteolytic IETD motif was partially processed when treated with caspase-3, while the DEVD motif was completely cleaved. The cleavage efficiency of the DEVD-based substrate was approximately 2.0 times higher than that of the IETD substrate, in response to caspase-3. Based on this, 3 protein genes of interest were genetically linked to each other by adding two proteolytic cleavage sequences, DEVD and IETD, for caspase-3. Particularly, glutathione-S transferase (GST), maltose binding protein (MBP), and red fluorescent protein (RFP) were chosen as model proteins due to the variation in their size. The expressed polyprotein was purified by immobilized metal ion affinity chromatography (IMAC) via a hexa-histidine tag at the C-terminal end, showing 93 kDa of a chimeric GST:MBP:RFP fusion protein. In response to caspase-3, cleavage products, such as MBP:RFP (68 kDa), MBP (42 kDa), RFP (26 kDa), and GST (25 kDa), were separated from a large precursor GST:MBP:RFP (93 kDa) via SDS-PAGE. The results obtained from this study indicate that a multi-protein can be stoichiometrically produced from a large poly-protein by using proteolytic recognition motifs, such as DEVD and IETD tetra-peptides, for caspase-3.

• Analytical Science and Technology
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• v.15 no.4
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• pp.329-334
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• 2002

Tributyl phosphate(TBP) is used in solvent extraction process for radioactive waste. This compound may be degraded to dibutyl phosphate($DBP^-$), monobutyl phosphate($MBP^{2-}$) and ${PO_4}^{3-}$ by radioactive material. Amount of $DBP^-$ and $MBP^{2-}$ in TBP must be monitored because they production of these compounds means degradation of which leads to a decrease in the extraction yield. Retention behavior for $DBP^-$, $MBP^{2-}$, $F^-$, $Cl^-$, ${NO_2}^-$, ${NO_3}^-$, ${SO_4}^{2-}$ and ${PO_4}^{3-}$ are studied with AS4A-SC(Dionex) analytical column and $Na_2CO_3$/NaOH eluent by Ion chromatography. Optimum condition for these anions is 2 mM $Na_2CO_3$/1 mM NaOH eluent. All anions by this condition is well separated within 15min. Dynamic range is $10{\mu}g/mL$ - $100{\mu}g/mL$ for DBP and $5{\mu}g/mL$ - $50{\mu}g/mL$ for $MBP^{2-}$, respectively. The Detection limit for AS4A-SC are $1{\mu}g/mL$ for $DBP^-$ and $0.5{\mu}g/mL$ for $MBP^{2-}$ in this system with a $25{\mu}L$ sample loop.

• Journal of Microbiology and Biotechnology
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• v.8 no.1
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• pp.34-41
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• 1998

A method was developed for the controlled expression of an antimicrobial peptide magainin in Escherichia coli. A series of concatemeric magainin genes was constructed with a gene amplification vector, and fused to the 3'end of malE gene encoding the affinity ligand, E. coli maltose-binding protein (MBP). The construct directed the synthesis of the fusion protein with the magainin polypeptide fused to the C-terminus of MBP. The fusion protein was expressed in a tightly regulatable expression system which was under the control of an invertible promoter. The MBP-fused magainin monomer was expressed efficiently. However, the expression level of the MBP-fused magainin in E. coli decreased with the increasing size of multimers possibly because of the transcription and translation inhibition by the multimeric peptides. After purification using an amylose affinity column, the fusion protein was digested by factor Xa at a specific cleavage site between the monomers. The recombinant magainin had an antimicrobial activity identical to that of synthetic magainin. This experiment shows that a biologically active, antimicrobial peptide magainin can be produced by fusing to MBP, along with a promoter inversion vector system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.45-57
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• 2005

In this paper, we extend the performance of bidirectional TCP connection over end-to-end network that uses transfer rate-based flow and congestion control. The sharing of a common buffer by TCP packets and acknowledgement has been known to result in an effect called ack compression, where acks of a connection arrive at the source bunched together, resulting in unfairness and degraded throughput. The degradation in throughput due to bidirectional traffic can be significant. Even in the simple case of symmetrical connections with adequate window size, the connection efficiency is improved about 20% for three levels of background traffic 2.5Mbps, 5.0Mbps and 7.5Mbps. Otherwise, the throughput of jitter is reduced about 50% because round trip delay time is smaller between source node and destination node. Also, we show that throughput curve is improved with connection rate algorithm which is proposed for TCP congetion avoidance as a function of aggressiveness threshold for three levels of background traffic 2.5Mbps, 5Mbps and 7.5Mbps. By analyzing the periodic bursty behavior of the source IP queue, we derive estimated for the maximum queue size and arrive at a simple predictor for the degraded throughput, applicable for relatively general situations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.639-644
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• 2011

By the development of the information superhighway, the current data communication system can be exchanged data quickly and precisely between subscribers. In this paper, LVTTL(Low Voltage Transistor Transistor Logic), Using the fundamental one logic at several kinds of used in communication systems, the LVTTL transmission characteristics were measured by according to the change data transfer rate and the transmission line length. Because the transmission line length required on the current system is 30cm, We analysed LVTTL data transfer characteristics according to the transmission line length required on the current system. The amplitude level of LVTTL at 10Mbps is 3V and 50Mbps is 2.2V and 100Mbps is 2V and 125Mbps is 1.5V and 150Mbps is 1.4V. The length of transmission line 30cm was stable state up to 100Mbps data transfer rate.