• Textile Coloration and Finishing
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• v.19 no.5
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• pp.24-29
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• 2007

It is well known that certain classes of dye are reducible to stable colorless leuco compounds, which can be oxidized in air back to the colored species. We now reported that bis(4-dialkylaminophenyl)squaraine dyes are readily reduced in solution by borohydride to give alkali soluble leuco compound, which exists in the 3-hydroxy 2,4-bis(4-dialkylaminophenyl)cyclobuten-one. New alkylamine leuco compounds were synthesized by the reaction of leuco chloro-squaraine with alkylamine derivatives. The leuco compounds are easily isolated and can be air oxidized back to the squaraine dyes. These dyes have many technical application. e.g. in xerography, solar cell, optical recording material, redox indicators, and enzyme assays.

• BMB Reports
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• v.51 no.12
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• pp.609-610
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• 2018

Glycosylation is one form of protein modification and plays a key role in protein stability, function, signaling regulation and even cancer. NleB and SseK are bacterial effector proteins and possess glycosyltransferase activity, even though they have different substrate preferences. NleB/SseKs transfer the GlcNAc sugar to an arginine residue of host proteins, leading to reduced $NF-{\kappa}B-dependent$ responses. By combining X-ray crystallography, NMR, molecular dynamics, enzyme kinetic assays and in vivo experiments, we demonstrated that a conserved HEN (His-Glu-Asn) motif in the active site plays a key role in enzyme catalysis and virulence. The lid-domain regulates the opening and closing of the active site and the HLH domain determines the substrate specificity. Our findings provide evidence for the enzymatic mechanism by which arginine can be glycosylated by SseK/NleB enzymes.

• Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.237-242
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• 2013

We investigated the antioxidant and angiotensin I converting enzyme (ACE) inhibitory activities of red snow crab Chionoecetes japonicas shell (RSCS) hydrolysate by enzymatic hydrolysis and its molecular weight cut-off fractions. The RSCS hydrolysate was fractionated through two ultrafiltration membranes of 3 and 10 kDa cut-offs. Three fractions (<3 kDa, 3-10 kDa, and >10 kDa) were evaluated for total amino acid composition, antioxidant activities using 2'-azino-bis[3-ethylbenzthiazoline-6-sulfonic acid] ($ABTS^+$) radical scavenging and superoxide dismutase (SOD)-like activities and reducing power assays, and ACE inhibitory activity using Hou's method. Although all fractions showed activity, the <3 kDa fraction of RSCS hydrolysate exhibited the greatest $ABTS^+$ radical scavenging, SOD-like and ACE inhibitory activities. However, these fractions exhibited low reducing power. These results suggest that the low-molecular-weight enzymatic hydrolysate of RSCS could be used as a functional ingredient to control oxidative stress and ACE activity.

• Biomolecules & Therapeutics
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• v.4 no.4
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• pp.402-407
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• 1996

Effects of oxidative stress on the induction of apoptosis and the activity of antioxidant enzymes were investigated in HL-60 cells using $H_2O$$_2$and cisplatin which generate oxygen species in the cell. Various concentrations of oxidants were treated to cells and at different incubation time, cells were harvested for assays. Cell viability, morphology by propidium iodide staining and DNA fragmentation by agarose gel electrophoresis were observed to determine whether they induce apoptosis. The activity of antioxidant enzymes such as superoxide dismutase and catalase was also measured to evaluate the cellular response to the oxidative damage. The results are as follows: $H_2O$$_2$ induced apoptosis at 10 $\mu$M after 6h incubation, while it took 12h for cisplatin. Both oxidants induced the superoxide dismutase activity at a tolerable low concentration. However, at a concentration which causes apoptotic cell death, the enzyme level was dropped markedly at first and then recovered to the normal level after which it declined again, probably due to cell death. On the other hand, changes in the activity of catalase were not significant at most concentrations except the statistically significant decrease at 24h after 10 $\mu$M-$H_2O$$_2$treatment. In this study, $H_2O$$_2$- and cisplatintreated cells showed similar results in apoptotic response and enzyme activities, suggesting that anticancer activity of cisplatin may be related, at least in part, to the production of oxygen free radicals.

• Mycobiology
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• v.43 no.1
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• pp.81-86
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• 2015

To promote the selection of promising monokaryotic strains of button mushroom (Agaricus bisporus) during breeding, 61 progeny strains derived from basidiospores of two different lines of dikaryotic parental strains, ASI1038 and ASI1346, were analyzed by nucleotide sequencing of the intergenic spacer I (IGS I) region in their rDNA and by extracellular enzyme assays. Nineteen different sizes of IGS I, which ranged from 1,301 to 1,348 bp, were present among twenty ASI1346-derived progeny strains, while 15 different sizes of IGS I, which ranged from 700 to 1,347 bp, were present among twenty ASI1038-derived progeny strains. Phylogenetic analysis of the IGS sequences revealed that different clades were present in both the ASI10388- and ASI1346-derived progeny strains. Plating assays of seven kinds of extracellular enzymes (${\beta}$-glucosidase, avicelase, CM-cellulase, amylase, pectinase, xylanase, and protease) also revealed apparent variation in the ability to produce extracellular enzymes among the 40 tested progeny strains from both parental A. bisporus strains. Overall, this study demonstrates that characterization of IGS I regions and extracellular enzymes is useful for the assessment of the substrate-degrading ability and heterogenicity of A. bisporus monokaryotic strains.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2121-2127
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• 2012

Objective: Deoxyribonucleoside kinase of Drosophila melanogaster (Dm-dNK) mutants have been reported to exert suicide gene effects in combined gene/chemotherapy of cancer. Here, we aimed to further evaluate the capacity of the mutanted enzyme and its potential for inhibiting cancer cell growth. Methods: We altered the sequence of the last 10 amino acids of Dm-dNK to perform site-directed mutagenesis and constructed active site mutanted Dm-dNK (Dm-dNKmut), RT-PCR and western bloting studies were used to reveal the expression of lentivirus mediated Dm-dNKmut in a breast cancer cell line (Bcap37), a gastric cancer cell line (SGC7901) and a colorectal cancer cell line (CCL187). [3H]-labeled substrates were used for enzyme activity assays, cell cytotoxicity was assessed by MTT assays, cell proliferation using a hemocytometer and apoptosis induction by thenannexin-V-FITC labeled FACS method. In vivo, an animal study was set out in which BALB/C nude mice bearing tumors were treated with lentivirus mediated expression of Dm-dNKmut with the pyrimidine nucleoside analog brivudine (BVDU, (E)-5-(2-bromovinyl)-(2-deoxyuridine). Results: The Dm-dNKmut could be stably expressed in the cancer cell lines and retained its enzymatic activity. Moreover, the cells expressing Dm-dNKmut exhibited increased sensitivity in combination with BVDU, with induction of apoptosis in vitro and in vivo. Conclusion: These findings underlined the importance of BVDU phosphorylated by Dm-dNKmut in transduced cancer cells and the potential role of Dm-dNKmut as a suicide gene, thus providing the basis for future intensive research for cancer therapy.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.2
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• pp.89-95
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• 2006

Potato plants carrying the Ry gene are extremely resistance to a number of potyviruses, but it is not known which variety expressed the resistance. In this investigation, combined classical and molecular techniques were used to identify virus resistance potatoes. Mechanical inoculation of 32 varieties of Korean potato cultivars, with potato virus Y (PVY), induced various symptoms, such as mosaic, yellowing, necrosis, mottle, vein clearing and vein bending. Different virus spreading patterns were observed, such as highly sensitive, moderate and resistant to $PVY^o$ inoculated leaves in different cultivars. From the results of double antibody sandwich-enzyme links immunosorbant assays (DAS-ELISA), coupled with reverse transcription polymerase chain reaction (RT-PCR), Winter valley and Golden valley were found to be highly susceptible and resistant cultivars to $PVY^o$ respectively. TEM was used as a complementary method to conform the localization of the virus in leaf tissues. TEM detect virus particles in Golden valley, where, ELISA and RT-PCR were unable to detect the CP gene. However, the interior part of the tissues was severely deformed in $PVY^o$ infected Winter valley, than Golden valley The Ry gene is involved in an induced response in $PVY^o$ infected Golden valley plants. The methods described in this study could be applied for the screening and development of antiviral potatoes.

• Journal of Applied Biological Chemistry
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• v.63 no.3
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• pp.181-188
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• 2020

In this study, Tongue fern (Pyrrosia lingua) plants that have been used traditionally as medicines. Their traditional medicinal uses, regions where indigenous people use the plants, parts of the plants used as medicines. This study was designed to assess the antioxidant and inhibition activities of extracts from P. lingua. In the P. lingua extracts was measured ethanol activity, 80.0% ethanol was high activity. The antioxidant activity was measured in 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-Azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), assays. DPPH and ABTS radical in this experiment, solid and phenolic of extract were tested, but only an average concentration of 100 ㎍/mL was used. However, the phenolic extract is shown phenolic activity reached a peak. Also, phenolic extracts ware reached peak water and ethanol extracts. As a result, using the phenolic extracts did other antioxidant assays such as DPPH, ABTS, protection factor, and thiobarbituric acid reactive substances at 50-200 ㎍/mL concentrations. The activity of elastase and collagenase, inhibiting their activities may retard skin aging. α-Glucosidase and α-amylase, inhibitors need to be explored for the benefit of postprandial hyperglycemia in diabetic patients. Activities of tyrosinase, hyaluronidase and xanthine oxidase inhibitors of these enzymes are increasingly important ingredients in cosmetics and medications to protect the skin against hyperpigmentation and skin aging. Inhibition effects were investigated using the P. lingua extracts at 50-200 ㎍/mL concentrations. The expression levels of enzyme inhibitions activities were decrease in dependent-concentrations manner when P. lingua extracts were treated.

• Korean Journal of Animal Reproduction
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• v.16 no.2
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• pp.87-102
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• 1992

A rapid, sensitive, and specific enzyme-linked immuno-sorbent assay (ELISA) for bovine casein was developed. Biotinylated casein and peroxidase-conjugated avidin were used in the assay with antibody separated from yolks of immunized hens. Caseins were biotinylated with sulfo-N-hydroxy succinimido biotin and peroxi-dase-conjugated avidin bound the biotinylated casein which became bound to immobilized anti-body on a microplate. The antibodies were specific for bovine $\alpha$- and $\beta$-caseins, and their cross-reactivities with whey proteins, IgG, and serum albumin from bovine were not detectable by ELISA and Western blot. Various sensitivities ranging from 2ng/ml to 20${\mu}\textrm{g}$/ml of casein were achieved, and were controlled by adding vanous concentrations of the biotinylated casein. Parallelism was observed between standard and sample curves. The coefficients of variation of intra-assays and inter-assays from the most sensitive assay were 5.5 and 5.7%, respectively, at the 50% displacement. Casein contents of peripaturient milk samples showed that casein secretion rapidly increased 3d prepartum.

• Microbiology and Biotechnology Letters
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• v.49 no.1
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• pp.45-56
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• 2021

Improved amylases were developed from protoplast fusants of two amylase-producing Aspergillus species. Twenty regenerated fusants were screened for amylase production using Remazol Brilliant Blue agar. Crude enzyme extracts produced by solid state fermentation of rice bran were assayed for activity. Three variable factors (temperature, pH and enzyme type) were optimized to increase the amylase activity of the parents and selected fusants using rice bran medium and solid state fermentation. Analysis of this optimization was completed using the Central Composite Design (CCD) of the Response Surface Methodology (RSM). Amylase activity assays conducted at room temperature and 80℃ demonstrated that Aspergillus designates, T5 (920.21 U/ml, 966.67 U/ml), T13 (430 U/ml, 1011.11 U/ml) and T14 (500.63 U/ml, 1012.00 U/ml) all exhibited improved function making them the preferred fusants. Amylases produced from these fusants were observed to be active over the entire pH range evaluated in this study. Fusants T5 and T14 demonstrated optimal activity under acidic and alkaline conditions, respectively. Fusants T13 and T14 produced the most amylase at 72 h while parents TA, TC and fusant T5 produced the most amylase after 96 h of incubation. Response surface methodology examinations revealed that the enzyme from fusant T5 was the optimal enzyme demonstrating the highest activity (1055.17 U/ml) at pH 4 and a temperature of 40℃. This enzyme lost activity with further increases in temperature. Starch hydrolysis using fusant T5 gave the highest yield of glucose (1.6158 g/100 ml). The significant activities of the selected fusants at 28 ± 2℃ and 80℃ and the higher sugar yields from cassava starch hydrolysis over their parental strains indicate that it is possible to improve amylase activity using the protoplast fusion technique.