• Journal of Microbiology and Biotechnology
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• 제28권7호
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• pp.1147-1155
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• 2018

The degradation efficiency and catabolism pathways of the different methylxanthines (MXs) in isolated caffeine-tolerant strain Pseudomonas putida CT25 were comprehensively studied. The results showed that the degradation efficiency of various MXs varied with the number and position of the methyl groups on the molecule (i.e., xanthine > 7-methylxanthine ${\approx}$ theobromine > caffeine > theophylline > 1-methylxanthine). Multiple MX catabolism pathways coexisted in strain CT25, and a different pathway would be triggered by various MXs. Demethylation dominated in the degradation of N-7-methylated MXs (such as 7-methylxanthine, theobromine, and caffeine), where C-8 oxidation was the major pathway in the catabolism of 1-methylxanthine, whereas demethylation and C-8 oxidation are likely both involved in the degradation of theophylline. Enzymes responsible for MX degradation were located inside the cell. Both cell culture and cell-free enzyme assays revealed that N-1 demethylation might be a rate-limiting step for the catabolism of the MXs. Surprisingly, accumulation of uric acid was observed in a cell-free reaction system, which might be attributed to the lack of activity of uricase, a cytochrome c-coupled membrane integral enzyme.

• Journal of Microbiology and Biotechnology
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• 제25권5호
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• pp.732-737
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• 2015

We present here an in silico search of fungal sterol-esterase/lipase and bacterial depolymerase sequences from environmental metagenomes. Both enzyme types contain the α/β-hydrolase protein fold. Analysis of DNA conserved motifs, protein homology search, phylogenetic analysis, and protein 3D modeling have been used, and the efficiency of these screening strategies is discussed. The presence of bacterial genes in the metagenomes was higher than those from fungi, and the sequencing depth of the metagenomes seemed to be crucial to allow finding enough diversity of enzyme sequences. As a result, a novel putative PHA-depolymerase is described.

• ALGAE
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• 제29권4호
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• pp.311-319
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• 2014

The biocide sodium hypochlorite (NaOCl) is widely used for controlling algal growth, and this application can be extended to marine environments as well. This study evaluates the biocidal efficiency and cellular toxicity of NaOCl on the harmful dinoflagellate Cochlodinium polykrikoides, with emphasis on pigment production and antioxidant enzyme activity. The test organism showed dose-dependent decrease in growth rate on exposure to NaOCl, and the 72 h $EC_{50}$ was measured to be $0.584mg\;L^{-1}$. NaOCl significantly decreased pigment levels and chlorophyll autofluorescence intensity, indicating possible detrimental effects on the photosystem of C. polykrikoides. Moreover, it significantly increased the activities of antioxidant enzymes, suggesting the production of reactive oxygen species in the cells. These data indicate that NaOCl exerted deleterious effects on the photosynthetic machinery and induced oxidative damage in the dinoflagellate and this biocide could be effectively used for the control of algal blooms.

• Microbiology and Biotechnology Letters
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• 제26권4호
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• pp.365-368
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• 1998

The aklavinone 11-hydroxylase which was overexpressed using T7 promoter in E. coli could be detected in SDS-PAGE only in insoluble precipitate without any detectable enzyme activity. The insoluble enzyme was solubilized in 6M guanidine$.$HCl solution and their refolding ability was tested under various conditions. When the enzymatic activity was checked by the bioconversion experiment, stepwise dialysis against 6M, 3M, 1M guanidine$.$HCl and finally 100 mM potassium phosphate buffer of the solubilized protein gave the best bioconversion efficiency. The aklavinone 11-hydroxylase showed its enzymatic activity in the reaction buffer containing NADPH with vigorous shaking. The enzymatic activity was lost during partial purification and regained by the addition of crude extract of S. lividans in the reaction mixture. This effect was confirmed to due to some low-molecular weight component(s) in the crude extract, because the addition of dialyzed crude extract could not recover the enzymatic activity.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• 제29권2호
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• pp.16-24
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• 1997

This experiment was mainly performed with a biological treatment of laser printed paper using enzyme, We got the following conclusions : In the case of nonionic surfactant treatment, brightness, residual ink contents and several strength properties of deinked paper were excellent at the low dosage of cellulase 0.05%. When mixed cellulase and xylanase was used, yield was increased as the dosage increased up to 0.2%, but brightness was decreased at the same condition. In contrast, deinking efficiency of anionic type was reduced in terms of brightness, residual ink contents, and tensile strength. As flotation time was increased, yield decreased and brightness increased slightly. On the other hand, the addition of surfactant during repulping process showed better result than that during flotation process.

• Journal of Microbiology and Biotechnology
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• 제30권7호
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• pp.1104-1107
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• 2020

The N-terminal domain of the Pseudomonas sp. FB15 phytase increases low-temperature activity and catalytic efficiency. In this study, the 3D structure of the N-terminal domain was predicted and substitutions for the amino acid residues of the region assumed to be the active site were made. The activity of mutants, in which alanine (A) was substituted for the original residue, was investigated at various temperatures and pH values. Significant differences in enzymatic activity were observed only in mutant E263A, suggesting that the amino acid residue at position 263 of the N-terminal domain is important in enzyme activity.

• International Journal of Vascular Biomedical Engineering
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• 제4권2호
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• pp.13-18
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• 2006

Direct injection of a fibrinolytic agent to the intra-arterial thrombosis may increase the effectiveness of thrombolysis by enhancing the permeation of thrombolytic agents into the blood clot. Permeation of fibrinolytic agents into a clot is influenced by the surface pressure, which is determined by the injection velocity of fibrinolytic agents. Computational fluid dynamic methods were used in order to predict clot lysis for different jet velocities and nozzle arrangements. Firstly, thrombolysis of a clot was mathematically modeled based on the pressure and lysis front velocity relationship. Direct injection of a thrombolytic agent increased the speed of thrombolysis significantly and the effectiveness was increased as the ejecting velocity increased. The nine nozzles model showed about 20% increase of the lysed volume, and the one and seventeen nozzles models did not show significant differences. Secondly, thrombolysis was modeled based on the enzyme transport and the fluid flow equations, and quasi steady numerical analysis was performed. Clot lysis efficiency was also increased as injection velocity increased.

• Korean Journal of Veterinary Service
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• 제22권1호
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• pp.9-13
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• 1999

Mycoplasmal pneumonia of swine(MPS) cause by Mycoplasma hyopneumoniae has been recognized as a serious impediment to swine production due to chronic respiratory disorder which result in the weight loss and decreased feed conversion. The disease causes a great economic losses in pig industry by characterizing with high morbidity, low mortality, growth retardation and low feed efficiency. The present study was conducted to investigate the titers of antibody against M hyopneumoniae from the regional and seasonal groups of the slaughtered pigs by enzyme-linked immunosorbent assay(ELISA). The result have shown that the average seropositive rate of M hyopneumoniae infection was 84.6% . The regional seropositive rate in Korea showed 87.4% in Kyonggj, 83.4n in Kangwon, 89.2% in Chungnam and 77.6% in Chungbuk area, respectively. Also the seasonal seropositive rate was appeared as 78.6% in spring,90.1% in summer, 76.9% in autumn and 83.8% in winter, respectively.

• Journal of Environmental Health Sciences
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• 제26권3호
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• pp.86-91
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• 2000

The purpose of this was to investigate the degradation efficiency of phenol compounds(catechol, ferulic acid, protocatechuic acid, syringic acid, vanillic acid) by Streptomyces halstedii scabies SAI-36, Streptomyces avendulas SA2-14, and Strptomyces badius(ATCC 39117, control group). The results were as follows: Catechol showed the degradation efficiency that is lower than 50% in three strains. Ferulic acid and vanillic acid showed high degradation efficiency of 98.8% and 94.5% respectively by Streptomyces lavendulas SA2-14. protocatechuic acid and syringicacid showed high degradation efficiency of 89.6% and 77.9%. The degradation efficiency of catechol by Streptomyces halstedii scabies SAI-36, Streptomyces lavendulas SA2-14 and Streptomyces badius(ATCC 39117) was low as 49.2%, 40.2% and 20.2% respectively. But the degradation of other phenolic compoumds except catechol by Streptomyces laven-dulas SA2-36 and Streptomyces badius(ATCC 39117). The results demonstrated that two experimental strains are superior ability to control group in degradation of phenol compounds and Streptomyces lavendulas SA2-14 was superior of two experimental strain. This results were consistent with previous research results that Streptomyces lavendulas SA2-14 was the best strain in degradation ability for lignin, decoloration abilities for variousdyes, and various enzyme production abilities. Therefore, it is suggested that lignin can be used as a indicator when selecting Actinomycetes for degradation of non-degradable materials such as phenol compounds.

• Korean journal of food and cookery science
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• 제28권1호
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• pp.51-55
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• 2012

This study was conducted to investigate the physicochemical properties of citrus peel extracts with different hot water extraction and enzymatic hydrolysis conditions. Enzymatic hydrolysis was also employed using Viscozyme L and results were compared with that of optimized hot water extract. Hot water extraction was performed under different parameters; the sample to solvent ratio(1:20, 1:15, 1:10), extraction time(2, 4 hrs), extraction temperature(85, $95^{\circ}C$) and enzymatic hydrolysis(0, 1%) and the subsequent extracts were used for determining their physicochemical properties, such as total yield, total phenolics, total flavonoids, and electron donating ability (EDA). With the increase in the sample to solvent ratio and extraction time, total yield, total phenolics, total flavonoids and EDA increased. But extraction temperature did not significantly affect the hot water extract. As hot water extract was hydrolyzed by the enzyme, total yield and active ingredients increased rapidly. In the result of total yield, total phenolics, total flavonoids and EDA, the activity of enzyme-treated extract was higher than those of enzyme-untreated extract. Based upon the overall hot water extraction efficiency, it was found that 20 times volume or 120 min at a time at $95^{\circ}C$ after enzyme treatment was optimal.