• Animal cells and systems
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• v.8 no.2
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• pp.125-133
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• 2004

We have extended our previous work that cross-linking CD4 molecules using specific MAb induced antigen nonspecific, MHC unrestricted killing of virally infected target cells by CD$4^+$We have extended our previous work that cross-linking CD$4^+$ molecules using specific MAb induced antigen nonspecific, MHC unrestricted killing of virally infected target cells by CD$4^+$ T cells. The killing activity of antibody activated CD$4^+$T cells was completely blocked by herbimycin A, a protein tyrosine kinase (PTK) inhibitor, but not by bisindolylamaleimide, a protein kinase C (PKC) inhibitor. Herbimycin A treated human or bovine peripheral blood CD$4^+$T cells lacked PTK activity and failed to kill virally infected target cells even after cross-linking of CD4 molecules. The CD$4^+$cross-linking failed to induce effector cell proliferation or the transcription of TNF${\beta}$ Upregulation of TNF${\beta}$ was induced by incubating the antibody activated effector cells with BHV-1 infected D17 target cells for 10 h. Anti-TNF${\beta}$ antibody partially abolished (13-44%) the direct effector cell-mediated antiviral cytotoxicity. However, this antibody neutralized 70 to 100% of antiviral activity of effector and target cell culture supernatants against BHV-1 infected D17 cells. The inhibition level of the antiviral activity by the antibody was dependent on the effector and target cell ratio. These results support the hypothesis that increased p$56^ICK enzyme activity in effector cells transduces a signal critical for effector cell recognition of viral glycoproteins expressed on the target cells. Following target cell recognition, lytic cytokines known to participate in target cell killing were produced. A better understanding of the killing activity displayed by CD$4^+$T lymphocytes following surface receptor cross-linking will provide insight into the mechanisms of cytotoxic activity directed toward virally-infected cells.T cells. The killing activity of antibody activated CD$4^+$T cells was completely blocked by herbimycin A, a protein tyrosine kinase (PTK) inhibitor, but not by bisindolylamaleimide, a protein kinase C (PKC) inhibitor. Herbimycin A treated human or bovine peripheral blood CD4T cells lacked PTK activity and failed to kill virally infected target cells even after cross-linking of CD4molecules. The CD4 cross-linking failed to induce effector cell proliferation or the transcription of TNF$\beta$. Upregulation of TNF$\beta$ was induced by incubating the antibody activated effector cells with BHV-1 infected D17 target cells for 10 h. Anti-TNF$\beta$ antibody partially abolished (13-44%) the direct effector cell-mediated antiviral cytotoxicity. However, this antibody neutralized 70 to 100% of antiviral activity of effector and target cell culture supernatants against BHV-1 infected D17 cells. The inhibition level of the antiviral activity by the antibody was dependent on the effector and target cell ratio. These results support the hypothesis that increased $56^ICK enzyme activity in effector cells transduces a signal critical for effector cell recognition of viral glycoproteins expressed on the target cells. Following target cell recognition, lytic cytokines known to participate in target cell killing were produced. A better understanding of the killing activity displayed by CD$4^+$T lymphocytes following surface receptor cross-linking will provide insight into the mechanisms of cytotoxic activity directed toward virally-infected cells.

• BMB Reports
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• v.29 no.4
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• pp.365-371
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• 1996

Partially reduced interferon-a ($IFN-{\alpha}$) was cross-linked with thymosin ${\alpha}1$ ($T{\alpha}1$) using sulfo-succinimidyl (4-iodoacetyl) amino benzoate (SIAB), a bifunctional cross-linking reagent. The partially reduced $IFN-{\alpha}$ optimal for the cross-linking reaction was obtained by incubating native $IFN-{\alpha}$ with 0.5 mM DTT at $30^{\circ}C$ for 60~100 min. $T{\alpha}1$ was activated by incubating with sulfo-SIAB at $37^{\circ}C$ for 30 min to produce $T{\alpha}1-IAB$. The $T{\alpha}1-IFN-{\alpha}$ cross-linking was achieved by the reaction of the partially reduced $IFN-{\alpha}$ with $T{\alpha}1-IAB$. This cross-linking was between the sulfhydryl group of Cys1 in $IFN-{\alpha}$ and the N-terminal amino group of $T{\alpha}1$ through acetyl amino benzoate as a spacer. The immunological activity of the cross-linked molecule showed the same extent as that of $T{\alpha}1$, and most of the antiviral activity was retained compared to that of the partially reduced $IFN-{\alpha}$.

• Korean Journal of Pharmacognosy
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• v.39 no.3
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• pp.249-254
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• 2008

An 80% EtOH extract and the solvent fractions of the seeds of Cornus officinalis were evaluated for their inhibitory activities against advanced glycation end products (AGEs) formation and AGEs-induced protein cross-linking in vitro. In vitro assay for AGEs-bovine serum albumin (BSA) formation showed that the 80% EtOH extract, n-hexane, EtOAc, n-BuOH and water fractions significantly inhibited AGEs formation with observed $IC_{50}$ values of 1.13, 17.64, 1.52, 1.24 and $3.27{\mu}g/ml$, respectively. In indirect AGEs-ELISA assay, the 800% EtOH extract, EtOAc and n-BuOH fractions exhibited more potent inhibitory activity on AGEs-BSA formation than aminoguanidine, a well know AGEs inhibitor. Furthermore, the 80% EtOH extract and all the solvent fractions inhibited concentration-dependently AGE-BSA cross-linking to collagen. The 80% EtOH extract, EtOAc, n-BuOH and water fractions also had a breaking activity against preformed AGE-BSA cross-linking concentration dependently. Thus these results suggest that the 80% EtOH extract and fractions of the seeds of C. officinalis could be an inhibitor as well as breaker of AGE-BSA cross-linking.

• Journal of Applied Biological Chemistry
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• v.59 no.1
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• pp.75-81
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• 2016

Glutaraldehyde was used as a cross-linking agent for immobilization of purified ${\alpha}$-amylase from Exiguobacterium sp. DAU5. Befitting concentration of glutaradehyde and cross-linking time is the key to preparation of cross-linking chitosan beads. Based on optimized immobilization condition for ${\alpha}$-amylase, an overall yield of 56% with specific activity of 2,240 U/g on chitosan beads and 58% with specific activity of 2,320 U/g on chitosan-carbon beads was obtained. The optimal temperature and pH of each immobilized enzyme activity were $50^{\circ}C$ and 50 mM glycine-NaOH buffer pH 8.5, respectively. Those retained more than 75 and 90% of its maximal enzyme activity at pH 7.0-9.5 and after incubation at $50^{\circ}C$ for 1 h, respectively. In addition, the immobilization product showed higher organic-solvent tolerance than free enzymes. The mode of hydrolyzing soluble starch revealed that the ${\alpha}$-amylase possessed high hydrolyzing activity. These results indicate that chitosan is good support and has broad application prospects of enzyme immobilization.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.223-227
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• 2007

Ground garlic inhibited the cross-linking reaction of myosin and incorporation of monodansylcadaverine (MDC) in salted Alaska pollack surimi catalyzed by transglutaminase (TGase). The component responsible for the inhibition was a thermostable, low molecular weight compound. The component also inhibited microbial transglutaminase (MTGase). The inhibition by garlic was reversibly recovered upon addition of 2-mercaptoethanol. The inhibitory component was therefore hypothesized to contain sulfhydryl groups within its structure. Alliin itself did not inhibit the cross-linking reaction. However, the addition of alliin together with garlic increased the inhibition. This result suggested that compounds derived from alliin was responsible for the inhibition of TGase activity.

• Proceedings of the Korean Biophysical Society Conference
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• 1996.07a
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• pp.46-46
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• 1996

To elucidate the mechanism for the cross-linking reaction in the glycation or Maillard reaction, we studied the reaction between proteins, and a three-carbon ${\alpha}$-ketoaldehyde, methylglyoxal. When Cu, Zn-SOD was incubated with 200 mM of methylglyoxal, the peroxidase activity as well as the superoxide dismutase activity was reduced. This reduction is accompanied by the decrease of the anion binding affinity of the enzyme. (omitted)

• Journal of the Society of Cosmetic Scientists of Korea
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• v.45 no.1
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• pp.19-25
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• 2019

Advanced glycation end products (AGEs) are final products formed by glycation reaction between reducing sugars and proteins, lipids or nucleic acids. These AGEs are related to progress of skin aging. In this study, we evaluate anti-aging activity of Defatted Torreya nucifera seed extract (DTSE) through antioxidant, anti-glycation, anti-elastase and inhibitory and breaking activity on the cross-linking of AGEs to collagen assay. Results showed that DTSE contained polyphenols and flavonoids. The $IC_{50}$ values of 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity were $16.4{\mu}g$ (Dried materials, DM)/mL and $16.7{\mu}g\;DM/mL$, respectively. DTSE also inhibited the formation of AGEs, elastase activity and cross-linking of AGEs to collagen as well as broke existing cross-linking of AGEs to collagen in a dose-dependent manner. Consequently, our findings suggest that DTSE could be useful as a cosmetic material with anti-aging activity.

• Archives of Pharmacal Research
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• v.24 no.5
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• pp.455-465
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• 2001

The highly potent cytotoxic DNA-DNA cross-linker consists of two cyclopropa[c]pyrrolo[3,4-3]indol-4(5H)-ones insoles [(+)-CPI-I] joined by a bisamido pyrrole (abbreviated to "Pyrrole"). The Pyrrole is a synthetic analog of Bizelesin, which is currently in phase II clinical trials due to its excellent in vivo antitumor activity. The Pyrrole has 10 times more potent cytotoxicity than Bizelesin and mostly form DNA-DNA interstrand cross-links through the N3 of adenines spaced 7 bp apart. The Pyrrole requires a centrally positioned GC base pair for high cross-linking reactivity (i.e., $5^1$-T$AT_2$A*-$3^1$), while Bizelesin prefers purely AT-rich sequences (i.e., $5^1$-T$AT_4$A*-$3^1$, where /(equation omitted) represents the cross-strand adenine alkylation and A* represents an adenine alkylation) (Park et al., 1996). In this study, the high-field $^1$H-NMR and rMD studies are conducted on the 1 1-mer DNA duplex adduct of the Pyrrole where the 5′(equation omitted)TAGTTA*-3′sequence is cross-linked by the drug. A severe structural perturbation is observed in the intervening sequences of cross-linking site, while a normal B-DNA structure is maintained in the region next to the drug-modified adenines. Based upon these observations, we propose that the interplay between the bisamido pyrrole unit of the drug and central C/C base pair (hydrogen-bonding interactions) is involved in the process of cross-linking reaction, and sequence specificity is the outcome of those interactions. This study suggests a mechanism for the sequence specific cross-linking reaction of the Pyrrole, and provides a further insight to develop new DNA sequence selective and distortive cross-linking agents.

• Journal of Information Science Theory and Practice
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• v.1 no.2
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• pp.58-68
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• 2013

Citing literature is a very important activity for scholars in writing articles. Many publishers and libraries build citation databases and provide citation reports on scholarly journals. Cited-by linking is a service representing what an article cites and how many times it cites a specific article within a journal database. Recently, information services based on DOIs (Digital Object Identifiers) have been increasing in number. CrossRef, a non-profit organization for the DOI registration agency, maintains the DOI system and provides the cited-by linking service. Recently, the number of Korean journals adopting DOI is also rapidly increasing. The Korea Institute of Science and Technology Information (KISTI) supports Korean learned societies in DOI related activities in collaboration with CrossRef. This study analyzes cited patterns of Korean DOI journal articles using CrossRef's cited-by linking data and a Korean journal citation database. This analysis has been performed in terms of publication country and the language of journals citing Korean journal articles. The results show that DOI, SCI(E) (Science Citation Index (Expanded)), and English journals are more likely to be cited internationally.

• BMB Reports
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• v.31 no.4
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• pp.355-363
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• 1998

MHC unrestricted, antigen nonspecific killing by $CD4^+$ T-cells against virally-infected target cells was induced following cross-linking of CD4 molecules. The cytotoxicity of antibody-activated $CD4^+$ T-cells was abolished by genistein (4',5,7-trihydroxyisoflavone), a protein tyrosine kinase (PTK) inhibitor, but not by H-7, a protein kinase C (PKC) inhibitor. Genisteintreated human or bovine peripheral blood $CD4^+$ T-cells lacked PTK activity and failed to kill virally-infected target cells even after cross-linking of CD4 molecules. The cross-linking of CD4 molecules did not induce effector cell proliferation or the transcription of TNF ${\beta}$. TNF ${\beta}$ synthesis was up-regulated by incubating antibody activated effector cells with bovine herpesvirus type 1 (BHV-1) infected D17 target cells. Anti-TNF ${\beta}$ antibody partially abrogated direct effector cell-mediated antiviral cytotoxicity. On the other hand, this antibody effectively neutralized antiviral activity of effector and target cell culture supernatants against BHV-1 infected D17 cells. The inhibition level of the antiviral activity by the antibody was dependent on effector and target cell ratio. These findings have importance to define the mechanisms of how CD4 cytotoxic cells control viral infection.