• Korean Journal of Microbiology
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• v.26 no.4
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• pp.283-290
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• 1988

A spontaneous revertant of mutation rbsB103 that is ribose taxis-positive was characterized. This revertant was found to be export-competent in the export of ribose-binding protein shown by the disappearance of accumulated mutant precursor protein and the export of mature ribose-binding protein to the periplasm. The reversional change was shown to be in the region of risB gene that codes for the amino terminal portion of ribose-binding protein. Analysis by high-performance liquid chromatography of peptide patterns of ribose-binding proteins confirmed the relationship between the wild-type and the revertant proteins as shown for the mutant previously (Iida et al., 1985). When the processing rate of presursor proteins from the wild type and the revertant strain in vivo was compared by pulse-chase experiment, it was found that processing is less efficient than normal in the revertant. Purified mature proteins from both wild-type and revertant were subjected to amino acid sequencing. The results confirmed the amino acid changes deduced from the DNA sequencing and showed that processing of the revertant precursor occured in the correct position even though there are two different amino acids present in the signal sequence.

• Journal of Life Science
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• v.7 no.4
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• pp.392-401
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• 1997

The poliovirus is a small, and non-enveloped virus. The RNA genome of poliovirus is continuous, linear, and has a single open reading frame. This polyprotein precursor is cleaved proteolytically to yield mature products. Most of the cleavages occur by viral protease. The mature proteins derived from the P1 polyprotein precursor are the structural components of the viral capsid. The initial cleavage by 2A protease is indirectly involved in the cleavage of a cellular protein p220, a subunit of the eukaryotic translation initiation factor 4F. This cleavage leads to the shut-off of cap-dependent host cell translation, and allows poliovirus to utilize the host cell machinery exclusively for translation its own RNA, which is initiated by internal ribosome entry via a cap-independent mechanism. The functional role of the 2B, 2C and 2BC proteins are not much known. 2B, 2C, 2BC and 3CD proteins are involved in the replication complex of virus induced vesicles. All newly synthesized viral RNAs are linked with VPg. VPg is a 22 amino acid polypeptide which is derived from 3AB. The 3C and 3CD are protease and process most of the cleavage sites of the polyprotein precursor. The 3C protein is also involved in inhibition of RNA polymerase II and III mediated transcription by converting host transcription factor to an inactive form. The 3D is the RNA dependent RNA polymerase. It is known that poliovirus replication follows the general pattern of positive strand RNA virus. Plus strand RNA is transcribed into complementary minus strand RNA that, in turn, is transcribed for the synthesis of plus strand RNA is transcribed into complementary minus strand RNA that, in turn, is transcribed for the synthesis of plus strand RNA strands. Poliovirus RNA synthesis occurs in a membranous environment but how the template RNA and proteins required for RNA replication assemble in the membrane is not much known. The RNA requirements for the encapsidation of the poliovirus genome (packaging signal) are totally unknown. The poliovirus infection cycle lasts approximately 6 hours.

• International Journal of Industrial Entomology and Biomaterials
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• v.15 no.1
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• pp.83-85
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• 2007

A glycine and proline-rich antibacterial protein was cloned from larvae of a beetle, Protaetia brevitarsis. The DNAs encoded a deduced propeptide of 127 amino acid residues with predicted molecular weight of 14.0 kDa and PI of 7.89. Structural analysis of this protein indicated the presence of a recognition sequence for the cleavage site within the constitutive secretory pathway(Arg-Xaa-Lys/Arg-Arg), suggesting that mature portion(72 amino acid residues) is produced by cleavage of signal peptide and propeptide from 127 amino-acid-long precursor protein. Mature portion sequence of this protein showed 72% similarity to that of Oryctes rhinoceros Rhinocerosin and 91% to that of Holotrichia diomphalia holotricin 2. The mRNA expression was reached the highest level at 4 hrs after E. coli injection and then declined gradually.

• BMB Reports
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• v.33 no.4
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• pp.294-299
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• 2000

Proteolytic processing of the dengue virus serotype 2 polyprotein precursor is catalyzed by a host signal peptidase and a virus encoded two-component protease consisting of the nonstructural proteins, NS2B and NS3. We expressed in Escherichia coli the NS2B, NS3(pro) and NS2B-NS3 proteins from the dengue virus type 2 strain 16681 as N-terminal fusions with a hexahistidine affinity tag under the control of the inducible trc promoter. All fusion proteins were purified to >90% purity by detergent extraction of inclusion bodies and a single step metal chelate chromatography. Proteins were refolded on-column and recovered with yields of 0.5, 6.0 and 1.0 mg/l of E. coli culture that was grown to $OD_{600}=1.0$ for NS2B, NS3(pro) and NS2B-NS3, respectively. Purified proteins gave strong signals in Western blots using $Ni^{2+}-nitrilotriacetic$ acid as a probe for the presence of the polyHis tag. During the purification process, $(His)_{6}NS2B-NS3$ was apparently not autoproteolytically cleaved at the NS2B/NS3 site.

• Journal of Microbiology and Biotechnology
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• v.21 no.2
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• pp.176-182
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• 2011

The study objective was to prepare biodegradable branched dextran microspheres encapsulated with His-tagged interferon-alpha (BDM-hIFN-${\alpha}$) and evaluate its activity in vitro and in vivo. The glycidyl methacrylate derivatized dextrans (Dex-GMA) as precursor was primarily synthesized by substituting hydroxyl groups of either the branched or linear type of dextran with GMA. Dex-GMA microspheres loaded with hIFN-${\alpha}$ was then prepared by the water-in-water emulsion technique. In vitro release and Western blotting experiments demonstrated the retained activity of hIFN-${\alpha}$ released from branched dextran microspheres at 24 h by inducing phosphorylation of signal transducer and activator transcription-1 (STAT-1), a down-stream effector of IFN-${\alpha}$, in HepG2 cells. Animal data further revealed a peak of plasma levels of IFN-${\alpha}$ in rats injected intravenously with BDM-hIFN-${\alpha}$ at 10 min post-injection, but a sharp decline at 2 h. High plasma levels of neopterin, a plasma protein induced by IFN-${\alpha}$, were also detected in rats injected with BDM-hIFN-${\alpha}$ at 10 min post-injection. Notably, plasma levels of neopterin remained high at 4 h, but largely declined thereafter.

• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1753-1759
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• 2006

Paenibacillus sp. HY-8 isolated from the digestive tracts of the longicorn beetle, Moechotypa diphysis, produced an extracellular endoxylanase with a molecular weight of 20 kDa estimated by SDS-PAGE. The xylanase was purified to near electrophoretic homogeneity from the culture supernatant after ammonium sulfate precipitation, gel filtration, and ionexchange chromatography. The purified xylanase exhibited the highest activities at pH 6.0 and $50^{\circ}C$. The $K_m\;and\;V_{max}$ values were 7.2 mg/ml and 16.3 U/mg, respectively, for birchwood xylan as the substrate. Nucleotide sequence of the PCR-cloned gene was determined to have the open reading frame encoding a polypeptide of 212 amino acids. The N-terminal amino acid sequence and the nucleotide sequence analyses predicted that the precursor xylanase contained a signal peptide composed of 28 amino acids and a catalytically active 19.9-kDa peptide fragment. The deduced amino acid sequence shared extensive similarity with those of the glycoside hydrolase family 11 of xylanases from other bacteria. The predicted amino acid sequence contained two glutamate residues, previously identified as essential and conserved for active sites in other xylanases of the glycoside hydrolase family 11.

• BMB Reports
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• v.35 no.6
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• pp.609-614
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• 2002

The remodeling process of bone is accompanied by complex changes in the expression levels of various genes. Several approaches have been employed to detect differentially-expressed genes in regard to osteoclast differentiation. In order to identify the genes that are involved in osteoclast differentiation, we used a cDNA-array-nylon membrane. Among 1,200 genes that showed ameasurable signal, 19 genes were chosen for further study. Eleven genes were up-regulated; eight genes were down-regulated. TIS21 was one of the up-regulated genes which were highly expressed in mature osteoclasts. To verify the cDNA microarray results, we carried out RT-PCR and real-time RT-PCR for the TIS21 gene. The TIS21 mRNA level was higher in differentiated-osteoclasts when compared to undifferentiated bone-marrow macrophages. Furthermore, the treatment with $1\;{\mu}M$ of a TIS21 antisense oligonucleotide reduced the formation of osteoclasts from the bone-marrow-precursor cells by ~30%. These results provide evidence for the potential role of TIS21 in the differentiation of osteoclasts.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.2
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• pp.106-111
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• 2009

Bisphosphonates have been approved for Paget's disease, cancer-related hypercalcemia, bone involvement in multiple myeloma or solid tumors and osteoporosis. Although, underlying pathophysiological mechanisms remain unclear, it seems that bisphosphonates inhibit osteoclast precursor cells, modulate migratory and adhesive characteristics and induce apoptosis of osteoclasts. Furthermore impacts on angiogenesis, microenvironment and signal transduction between osteoclasts and osteoblasts. In this report, we present a case of oral bisphosphonates induced osteonecrosis of the mandible in a 84-year-old patient who received for two years. Two tapered screw vent implants(Zimmer, USA) were placed in the area of first and second molar. Two weeks later after crowns restored, some inflammatory signs and symptoms were observed on the second molar area. Sequestrum was formed and the sequestrum was removed with the implant. Frequent follow-up checks and oral hygiene maintenances were done and the first molar implant was restored. There is insufficient evidence suggests that duration of oral bisphosphonate therapy correlates with the development and severity of osteonecrosis. Therefore, dentists should not overlook the possibility of development of bisphosphonate induced osteonecrosis in patients who have taken oral forms of medication for less than three years.

• Molecules and Cells
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• v.40 no.10
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• pp.706-713
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• 2017

Osteoclasts are bone-resorbing cells that are derived from hematopoietic precursor cells and require macrophage-colony stimulating factor and receptor activator of nuclear factor-${\kappa}B$ ligand (RANKL) for their survival, proliferation, differentiation, and activation. The binding of RANKL to its receptor RANK triggers osteoclast precursors to differentiate into osteoclasts. This process depends on RANKL-RANK signaling, which is temporally regulated by various adaptor proteins and kinases. Here we summarize the current understanding of the mechanisms that regulate RANK signaling during osteoclastogenesis. In the early stage, RANK signaling is mediated by recruiting adaptor molecules such as tumor necrosis factor receptorassociated factor 6 (TRAF6), which leads to the activation of mitogen-activated protein kinases (MAPKs), and the transcription factors nuclear factor-${\kappa}B$ (NF-${\kappa}B$) and activator protein-1 (AP-1). Activated NF-${\kappa}B$ induces the nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), which is the key osteoclastogenesis regulator. In the intermediate stage of signaling, the co-stimulatory signal induces $Ca^{2+}$ oscillation via activated phospholipase $C{\gamma}2$ ($PLC{\gamma}2$) together with c-Fos/AP-1, wherein $Ca^{2+}$ signaling facilitates the robust production of NFATc1. In the late stage of osteoclastogenesis, NFATc1 translocates into the nucleus where it induces numerous osteoclast-specific target genes that are responsible for cell fusion and function.

• Journal of Periodontal and Implant Science
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• v.32 no.4
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• pp.721-731
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• 2002

Recently, soluble TNF receptor homolog osteoprotegerin(OPG) and its membrane-bound ligand osteoclast differentiation factor(ODF) were found to regulate osteoclast formation and function, and bone metabolism. It is now well established that ODF acts via RANK expressed on hematopoietic osteoclast precursor cells to facilitate their differentiation to osteoclasts, and OPG prevents the formation of osteoclasts by interfering the binding of ODF and RANK. Expression of OPG and ODF was believed to be closely related to the pathogenesis of bone resorption and destruction from osteoporosis, periodontal diseases, malignant bone tumor, and arthritis. The periodontal ligament fibroblasts (PDLF), located between the tooth and tooth socket, has been thought to play an important role in maintaining bone homeostasis of periodontal tissues. However, the exact mechanism by which bone formation and resorption are regulated by PDLF is not well understood. In this study we have prepared primary cultures of human PDLF from periodontium of malaligned tooth extracted due to orthodontic reason, and determined steady state or inflammatory signal-induced OPG and ODF expression using RT-PCR and western blot analysis. OPG and ODF mRNA and protein were expressed constitutively in the PDLF and these expression were slightly increased by osteotropic cytokine IL-1 ${\beta}$. Lipopolysaccharide-treated PDLF showed decrease in OPG mRNA and protein expression, and increase in ODF mRNA and protein expression. These results indicated that PDLF influence the osteoclastogenesis by OPG and ODF expression in the inflammatory situation as well as physiological condition, and thereby pathogenesis of periodontal alveolar bone destruction.