• Journal of Microbiology and Biotechnology
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• v.34 no.4
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• pp.930-939
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• 2024

Mushroom laccases play a crucial role in lignin depolymerization, one of the most critical challenges in lignin utilization. Importantly, laccases can utilize a wide range of substrates, such as toxicants and antibiotics. This study isolated a novel laccase, named HeLac4c, from endophytic white-rot fungi Hericium erinaceus mushrooms. The cDNAs for this enzyme were 1569 bp in length and encoded a protein of 523 amino acids, including a 20 amino-acid signal peptide. Active extracellular production of glycosylated laccases from Saccharomyces cerevisiae was successfully achieved by selecting an optimal translational fusion partner. We observed that 5 and 10 mM Ca²⁺, Zn²⁺, and K⁺ increased laccase activity, whereas 5 mM Fe²⁺ and Al³⁺ inhibited laccase activity. The laccase activity was inhibited by the addition of low concentrations of sodium azide and ⳑ-cysteine. The optimal pH for the 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt was 4.4. Guaiacylglycerol-β-guaiacyl ether, a lignin model compound, was polymerized by the HeLac4c enzyme. These results indicated that HeLac4c is a novel oxidase biocatalyst for the bioconversion of lignin into value-added products for environmental biotechnological applications.

• BMB Reports
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• v.40 no.5
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• pp.636-643
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• 2007

This study was designed to identify and characterize the mechanism of macrophage activation by AAP, an acidic polysaccharide fraction isolated from the roots of Angelica sinensis (Oliv.) Diels. As a result, AAP significantly enhanced nitric oxide (NO) production and cellular lysosomal enzyme activity in murine peritoneal macrophages in vitro and in vivo. Furthermore, L-NAME, a specific inhibitor of inducible nitric oxide synthase (iNOS), effectively suppressed AAP-induced NO generation in macrophages, indicating that AAP stimulated macrophages to produce NO through the induction of iNOS gene expression and the result was further confirmed by the experiment of the increase of AAP-induced iNOS transcription in a dose-dependent manner. To further investigate, AAP was shown to strongly augment toll-like receptor 4 (TLR4) mRNA expression and the pretreatment of macrophages with anti-TLR4 antibody significantly blocked AAP-induced NO release and the increase of iNOS activity, and tumor necrosis factor-$\alpha$ (TNF-$\alpha$) secretion.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.10
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• pp.1508-1514
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• 2016

A series of antagonists specifically targeting growth hormone receptors (GHR) in different species, such as humans, rats, bovines, and mice, have been designed; however, there are currently no antagonists that target the porcine growth hormone (GH). Therefore, in this study, we developed and characterized a porcine GHR (pGHR) antibody antagonist (denoted by AN98) via the hybridoma technique. The results from enzyme-linked immunosorbent assay, fluorescence activated cell sorter, indirect immunoinfluscent assay, and competitive receptor binding analysis showed that AN98 could specifically recognize pGHR, and further experiments indicated that AN98 could effectively inhibit pGH-induced signalling in CHO-pGHR cells and porcine hepatocytes. In addition, AN98 also inhibited GH-induced insulin-like growth factor-1 (IGF-1) secretion in porcine hepatocytes. In summary, these findings indicated that AN98, as a pGHR-specific antagonist, has potential applications in pGH-pGHR-related research on domestic pigs.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.89-92
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• 2001

Aspergillus niger has been used as a host system to express many heterologous proteins. It has various advantages over other expression systems in that it is a small eukaryotic GRAS (Generally Recognized aS Safe) organism with a capacity of secreting large amount of foreign proteins. However, it has been known that the presence of an abundant protease is a limiting factor to express a heterologous protein. The proteases deficient mutants of A. niger were obtained using UV -mutagenesis. A total of 1 ${\times}$ $10^5$ spores were irradiated with 10-20% survival dose of UV, 600J/M2 at 280nm, and the resulting spores were screened on the casein -gelatin plates. Ten putative protease deficient mutants were further analyzed on the starch plates to differentiate the pro from the secretory mutant. An endogenous extracellular enzyme, glucose oxidase, was also examined to confirm that the mutant phenotype was due to the proteases deficiency rather than the mutation in the secretory pathway. The reduced proteolytic activity was measured using SDS-fibrin zymography gel, casein degradation assay, and bio-activity of a supplemented hGM -CSF (human Granulocyte-Macrophage Colony Stimulating Factor). Comparing with the wild type strain, less than 30 % of proteolytic activity was observed in the culture filtrate of the protease deficient mutant (pro -20) without any notable changes in cell growth and secretion.

• Nutrition Research and Practice
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• v.8 no.5
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• pp.494-500
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• 2014

BACKGROUND/OBJECTIVES: This study investigated whether Padina arborescens extract (PAE) protects INS-1 pancreatic ${\beta}$ cells against glucotoxicity-induced apoptosis. MATERIALS/METHODS: Assays, including cell viability, lipid peroxidation, generation of intracellular ROS, NO production, antioxidant enzyme activity and insulin secretion, were conducted. The expressions of Bax, Bcl-2, and caspase-3 proteins in INS-1 cells were evaluated by western blot analysis, and apoptosis/necrosis induced by high glucose was determined by analysis of FITC-Annexin V/PI staining. RESULTS: Treatment with high concentrations of glucose induced INS-1 cell death, but PAE at concentrations of 25, 50 or $100{\mu}g/ml$ significantly increased cell viability. The treatment with PAE dose dependently reduced the lipid peroxidation and increased the activities of antioxidant enzymes reduced by 30 mM glucose, while intracellular ROS levels increased under conditions of 30 mM glucose. PAE treatment improved the secretory responsiveness following stimulation with glucose. The results also demonstrated that glucotoxicity-induced apoptosis is associated with modulation of the Bax/Bcl-2 ratio. When INS-1 cells were stained with Annexin V/PI, we found that PAE reduced apoptosis by glucotoxicity. CONCLUSIONS: In conclusion, the present study indicates that PAE protects against high glucose-induced apoptosis in pancreatic ${\beta}$ cells by reducing oxidative stress.

• Korean Journal of Pharmacognosy
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• v.34 no.1 s.132
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• pp.70-74
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• 2003

Cornis fructus has been traditionally used for treating allergy, asthma, hepatitis, and chronic nephritis. It major chemical constituents have been saponins, phenolic acids and loganin. The main aim of the present study was to examine the effect of methanol extract from Cornis fructus on melanogenesis. Cell were cultured in the presence of methanol extracts from Cornis fructus for 48 h, and there were estimated total melanin content as a final product and activity of tyrosinase, a key enzyme, in melanogenesis. Methanol extract from Cornis fructus increased the melanin content and tyrosinase activity in a dose-dependent manner. Particularly, it was observed that only methanol extract $200\;{\mu}g/ml$ stimulated the melanin secretion in B16/F10 melanoma cells by 152% at 48 h treatment and the activity of tyrosinase was increased by 261% in the presence of same concentration.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.4
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• pp.818-822
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• 2002

Fruits of Cornus Officinalis have been used as an astrinent, tonic and haemostatic in chinese medicine, contain a large amount of hydrolyzable tannins. The main aim of the present study was to examine the effect of Corni Fructus on melanogenesis. Cells were cultured in the presence of water extracts from Corni Fructus for 48 h, and there were estimated total melanin content as a final product and activity of tyrosinase, a key enzyme, in melanogenesis. Water extract from Corni Fructus increased the melanin content and tyrosinase activity in a dose-dependent mammer. Especially, It was observed that 100 μg/ml only water extract stimulated melanin secretion in B16/F10 melanoma cells by 130% at 48 h treatment and activity of tyrosinase increased by 160% in presence of same concentration.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1190-1195
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• 2004

In recent years, there has been an intensive research on decolorization of dye and textile wastewater by various fungal strains. In this study, the decolorization ability of three commercial dyes, acid yellow 99, acid blue 350, and acid red 114, were investigated using 10 fungal strains. Among the fungal strains tested, Trametes versicolor KCTC 16781 completely decolorized all dyes in both solid and liquid experiments, and was also able to decolorize the mixture of those three dyes in liquid experiments. The secretion of the ligninolytic enzymes into the extracellular medium during decolorization by T versicolor KCTC 16781 was also studied. No lignin peroxidase activity was detected, and manganese peroxidase and laccase activities were investigated.

• Journal of Nutrition and Health
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• v.31 no.3
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• pp.363-368
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• 1998

Taurine is only supplied to the infants from the breast-fed or formula milks because the enzyme activities of taurine biosynthesis are limited in early stages of infants . The objectives of present study were to quantitate the contents of tarurine in human milk and to estimate the intake of taurine by breast-fed infants during early period of lactation. Thirty -three lactating women, volunteered and delivered in R hospital in Serou. were recruited. Milk samples were collected every day at B1-B5 day(from 1 to 5 day dafter start of milk secretion), 15th and 30th day postpartum. Taurine contents were determined by HPLC equipped with RF-detector. The intake of taurine by infants was estimated by multiplization with the infant milk intake reported in our laboratory. The content of taurine was 406$\pm$174nmol/ml at B1-B5 day, and then gradually decreased to 359$\pm$125nmol/ml at 15th day and to 304$\pm$94nmol/ml at 30th day postpartum. The estimated intake of taurine was almost same as 24-25mg/day at B1-B5 day, and 15th , 30th days postpartum . This results was due to the increase of the intake of milk by infants.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.6
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• pp.409-416
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• 2009

Acute pancreatitis is a multifactorial disease associated with the premature activation of digestive enzymes. The genes expressed in pancreatic acinar cells determine the severity of the disease. The present study determined the differentially expressed genes in pancreatic acinar cells treated with cerulein as an in vitro model of acute pancreatitis. Pancreatic acinar AR42J cells were stimulated with $10^{-8}$ M cerulein for 4 h, and genes with altered expression were identified using a cDNA microarray for 4,000 rat genes and validated by real-time PCR. These genes showed a 2.5-fold or higher increase with cerulein: lithostatin, guanylate cyclase, myosin light chain kinase 2, cathepsin C, progestin-induced protein, and pancreatic trypsin 2. Stathin 1 and ribosomal protein S13 showed a 2.5-fold or higher decreases in expression. Real-time PCR analysis showed time-dependent alterations of these genes. Using commercially available antibodies specific for guanylate cyclase, myosin light chain kinase 2, and cathepsin C, a time-dependent increase in these proteins were observed by Western blotting. Thus, disturbances in proliferation, differentiation, cytoskeleton arrangement, enzyme activity, and secretion may be underlying mechanisms of acute pancreatitis.