• The Korean Journal of Mycology
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• v.32 no.2
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• pp.119-124
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• 2004

Metalloenzyme was purified from the fruiting bodies of Tricholoma sejunctum. MALDI-TOF and ICP/MS analyses revealed that the enzyme had a molecular weight of 18788.25 and includes $Zn^{2+}$ ion. The N-terminal amino acid sequence of the enzyme was Ala-Thr-Tyr-Lys-Ile-X-Ser-Ala-Thr-His-Gln-X-X-Leu-Val. The activity of the enzyme was inhibited by EDTA and 1,10-phenanthroline, indicating that the enzyme was a metalloprotease. No inhibition was found with E-64 and pepstatin. It has broad substrate specificity for synthetic peptides. The enzyme was stable up to $40^{\circ}C$. The activity of the enzyme was increased by $Zn^{2+}$ and $Co^{2+}$, while it was totally inhibited by $Hg^{2+}$. The enzyme hydrolyzes $A{\alpha}$ subunit of human fibrinogen but did not show any reactivity for $B{\beta}$ and ${\gamma}$ form of human fibrinogen.

• Nutrition Research and Practice
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• v.11 no.3
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• pp.198-205
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• 2017

BACKGROUND/OBJECTIVES: The anti-diabetic activity of pear through inhibition of ${\alpha}-glucosidase$ has been demonstrated. However, little has been reported about the effect of pear on insulin signaling pathway in obesity. The aims of this study are to establish pear pomace 50% ethanol extract (PPE)-induced improvement of insulin sensitivity and characterize its action mechanism in 3T3-L1 cells and high-fat diet (HFD)-fed C57BL/6 mice. MATERIALS/METHODS: Lipid accumulation, monocyte chemoattractant protein-1 (MCP-1) secretion and glucose uptake were measure in 3T3-L1 cells. Mice were fed HFD (60% kcal from fat) and orally ingested PPE once daily for 8 weeks and body weight, homeostasis model assessment of insulin resistance (HOMA-IR), and serum lipids were measured. The expression of proteins involved in insulin signaling pathway was evaluated by western blot assay in 3T3-L1 cells and adipose tissue of mice. RESULTS: In 3T3-L1 cells, without affecting cell viability and lipid accumulation, PPE inhibited MCP-1 secretion, improved glucose uptake, and increased protein expression of phosphorylated insulin receptor substrate 1 [p-IRS-1, ($Tyr^{632})$)], p-Akt, and glucose transporter type 4 (GLUT4). Additionally, in HFD-fed mice, PPE reduced body weight, HOMA-IR, and serum lipids including triglyceride and LDL-cholesterol. Furthermore, in adipose tissue, PPE up-regulated GLUT4 expression and expression ratio of p-IRS-1 ($Tyr^{632})/IRS$, whereas, down-regulated p-IRS-1 ($Ser^{307})/IRS$. CONCLUSIONS: Our results collectively show that PPE improves glucose uptake in 3T3-L1 cells and insulin sensitivity in mice fed a HFD through stimulation of the insulin signaling pathway. Furthermore, PPE-induced improvement of insulin sensitivity was not accompanied with lipid accumulation.

• BMB Reports
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• v.33 no.4
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• pp.317-320
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• 2000

The succinic semialdehyde dehydrogenase from bovine brain was inactivated by treatment with phenylglyoxal, a reagent that specifically modifies arginine residues. The inhibition at various phenylglyoxal concentrations shows pseudo-first-order kinetics with an apparent secondorder rate constant of 30 $M^{-1}min^{-1}$ for inactivation. Partial protection against inactivation was provided by the coenzyme $NAD^+$, but not by the substrate succinic semialdehyde. Spectrophotometric studies indicated that complete inactivation of the enzyme resulted from the binding of 2 mol phenylglyoxal per mol of enzyme. These results suggest that essential arginine residues, located at or near the coenzyme-binding site, are connected with the catalytic activity of brain succinic semialdehyde dehydrogenase.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1286-1294
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• 2004

In a previous study by the current authors, hepatocellular carcinoma (HCC) was determined to be epidemiologically sex-dependent, and the incidence and multiplicity of HCC found to decrease in estradiol-3 benzoate (EB)-treated F344 rats. Therefore, to ascertain the anticancer mechanism of EB, a commercially available cDNA microarray, with a total of 14,815 cDNA rat gene clones, was used to determine the differentially expressed genes in nontreated livers, EB-treated livers, and diethynitrosolamine (DEN)-induced HCC. In the sequenced experiment, a total of 85 genes were differentially expressed at either two or more times the rate of the normal expression, where 33 genes were downregulated by EB, and 52 genes upregulated. Candidate genes were selected according to significant changes observed in the mRNA expression in the EB-treated livers compared with the nontreated livers, then these genes were filtered according to their different expression patterns in the DEN-induced tumors compared to the estrogen-treated livers. To confirm the microarray data, a real-time PCR analysis was performed for ten selected genes: the H-ras revertant protein 107 (H­rev107), insulin-like growth factor binding protein (lOFBP), parathyroid hormone receptor (PI'HR), SH3 domain binding protein (SH3BP), metallothionein, src-suppressed C-kinase substrate (SSeCK) gene, phosphodiesterase I, CD44, epithelial membrane protein 3 (EMP3), and estrogen receptor a (ERa). The SSeCK and phosphodiesterase I genes were both upregulated in the DEN-induced hepatocarcinomas, yet their possible carcinogenic functions remain unknown. Meanwhile, the other genes were downregulated, including the genes related to growth regulation (IOFBP, H-revI07, ER$\alpha$), adipogenesis inhibition (PTHR), and tumor suppression (metallothionein).

• Microbiology and Biotechnology Letters
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• v.8 no.4
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• pp.229-235
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• 1980

Pectin transeliminase (PTE) was produced by Saccharomyces cerevisiae, Schizosaccharomyces pombe 4683, and Aspergillus niger in the media containing 2% pectin and examined for its characteristics. The Production of the enzyme was higher by Asp. niger than by the two yeast strains, showing that the PTE activity was proportional to reducing power. The enzyme was proved to reduce pectin and produce 4, 5- unsaturated galacturonic acid. The optimum activity of the PTE was found to be at pH 6.0 and $50^{\circ}C$. The activities of these enzyme were stable below $50^{\circ}C$ but decreased at the higher temperature. Substrate inhibition of the PTE activities was appeared at high concentrations of pectin. Those PTE activities were increased under 0.6M of KCI and NaCI, but that maximal activities at the concentration of 0.2M MgC $l_2$.

• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1216-1225
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• 2014

Biofilm-related infections of Candida albicans are a frequent cause of morbidity and mortality in hospitalized patients, especially those with immunocompromised status. Options of the antifungal drugs available for successful treatment of drug-resistant biofilms are very few, and as such, new strategies need to be explored against them. The aim of this study was to evaluate the efficacy of phenylpropanoids of plant origin against planktonic cells, important virulence factors, and biofilm forms of C. albicans. Standard susceptibility testing protocol was used to evaluate the activities of 13 phenylpropanoids against planktonic growth. Their effects on adhesion and yeast-to-hyphae morphogenesis were studied in microplate-based methodologies. An in vitro biofilm model analyzed the phenylpropanoid-mediated prevention of biofilm development and mature biofilms using XTT-metabolic assay, crystal violet assay, and light microscopy. Six molecules exhibited fungistatic activity at ${\leq}0.5mg/ml$, of which four were fungicidal at low concentrations. Seven phenylpropanoids inhibited yeast-to-hyphae transition at low concentrations (0.031-0.5 mg/ml), whereas adhesion to the solid substrate was prevented in the range of 0.5-2 mg/ml. Treatment with ${\leq}0.5mg/ml$ concentrations of at least six small molecules resulted in significant (p < 0.05) inhibition of biofilm formation by C. albicans. Mature biofilms that are highly resistant to antifungal drugs were susceptible to low concentrations of 4 of the 13 molecules. This study revealed phenylpropanoids of plant origin as promising candidates to devise preventive strategies against drug-resistant biofilms of C. albicans.

• Journal of Microbiology and Biotechnology
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• v.28 no.2
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• pp.255-261
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• 2018

Aglycon protopanaxatriol (APPT) has valuable pharmacological effects such as memory enhancement and tumor inhibition. ${\beta}$-Glycosidase from the hyperthermophilic bacterium Dictyoglomus turgidum (DT-bgl) hydrolyzes the glucose residues linked to APPT, but not other glycoside residues. ${\beta}$-Glycosidase from the hyperthermophilic bacterium Pyrococcus furiosus (PF-bgl) hydrolyzes the outer sugar at C-6 but not the inner glucose at C-6 or the glucose at C-20. Thus, the combined use of DT-bgl and PF-bgl is expected to increase the biotransformation of PPT-type ginsenosides to APPT. We optimized the ratio of PF-bgl to DT-bgl, the concentrations of substrate and enzyme, and the reaction time to increase the biotransformation of ginsenoside Re and PPT-type ginsenosides in Panax ginseng leaf extract to APPT. DT-bgl combined with PF-bgl converted 1.0 mg/ml PPT-type ginsenosides in ginseng leaf extract to 0.58 mg/ml APPT without other ginsenosides, with a molar conversion of 100%. We achieved the complete biotransformation of ginsenoside Re and PPT-type ginsenosides in ginseng leaf extract to APPT by the combined use of two ${\beta}$-glycosidases, suggesting that discarded ginseng leaves can be used as a source of the valuable ginsenoside APPT. To the best of our knowledge, this is the first quantitative production of APPT using ginsenoside Re, and we report the highest concentration and productivity of APPT from ginseng extract to date.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.2
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• pp.185-193
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• 1997

The characteristics of $Na^+$-dependent cycloleucine uptake was investigated in OK cells with regard to substrate specificity and regulation by protein kinase C (PKC). Inhibition studies with different synthetic and natural amino acids showed a broad spectrum affinity to neutral amino acids regardless of their different side chains including branched or aromatic, indicating that the $Na^+$-dependent cycloleucine uptake in OK cells is mediated by System $B^o$ or System $B^o$-like transporter rather than the classical System A or ASC. Phorbol 12-myristate 13-acetate (PMA) and phorbol 12,13-dibutyrate, but not $4{\alpha}-PMA$ elicited a time-dependent biphasic stimulation of $Na^+$-dependent cycloleucine uptake, which produced early transient peak at 30 min and late sustained peak at 180min. Both the early and late stimulations by PMA were due to an increase in Vmax and not due to a change in Km. PKC inhibitors blocked both the early and late stimulation by PMA, while protein synthesis inhibitors blocked the late stimulation only. These results suggest the existence and regulation by PKC of System $B^o$ or System $B^o$-like broad spectrum transport system for neutral amino acids in OK cells.

• Microbiology and Biotechnology Letters
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• v.16 no.3
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• pp.187-192
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• 1988

Production of 4-androstene-3,17-dione(AD) from cholesterol by microbial conversion was investigated. To facilitate the solubilization of cholesterol in the fermentation broth, ethanol was used as an organic solvent. Inhibition on cell growth by ethanol was observed to be negligible upto 2% (V/V) concentration. Microbial conversion was successfully carried out with high yield when the cholesterol was added at early logarithmic growth phase with pH control at 7.0. In order to improve the process productivity, bioconversion was conducted at various mode of cholesterol addition ; 0.1% (V/W) of cholesterol was found to be most appropriate for solubilization in ethanol and was added intermittently. When added three time(total 3 g/$\ell$), overall bioconversion yield reached upto 65% while single addition of same amount of cholesterol (3 g/$\ell$) yielded about 40% conversion.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.12
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• pp.2107-2113
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• 2000

Toxicity estimation of three nonionic surfactants (Brij 30, Tween 80, Triton X-lOO) and their effect on the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in the aqueous phase and soil slurry phase were investigated. Brij 30 was found to be the most biodegradable among the surfactants tested, and showed no substrate inhibition up to a concentration of 1.5 g/L. It was definitely utilized as a carbon source by the microorganisms. Naphthalene and phenanthrene in the aqueous phase were completely degraded by phenanthrene-acclimated cultures within 60 hours, but a substantial amount of naphthalene was lost due to the volatilization. The limiting step in the soil slurry bioremediation was bioavailablity by the microorganisms in the sand slurry and mass transfer from a solid to aqueous phase in the clay slurry. TOC analysis revealed that most of substrates including surfactant in the reactor were degraded. pH transition indicated that phenanthrene was metabolized into intermediates containing acid function.