• Journal of Microbiology and Biotechnology
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• v.23 no.4
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• pp.499-510
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• 2013

Among 25 isolates, Aspergillus fumigatus ASH (JX006238) was identified as a potent producer of homocysteine ${\gamma}$-lyase. The nutritional requirements to maximize the enzyme yield were optimized under submerged (SF) and solid-state fermentation (SSF) conditions, resulting in a 5.2- and 2.3-fold increase, respectively, after the last purification step. The enzyme exhibited a single homogenous band of 50 kDa on SDS-PAGE, along with an optimum pH of 7.8 and pH stability range of 6.5 to 7.8. It also showed a pI of 5.0, as detected by pH precipitation with no glycosyl residues. The highest enzyme activity was obtained at $37-40^{\circ}C$, with a $T_m$ value of $70.1^{\circ}C$. The enzyme showed clear catalytic and thermal stability below $40^{\circ}C$, with $T_{1/2}$ values of 18.1, 9.9, 5.9, 3.3, and 1.9 h at $30^{\circ}C$, $35^{\circ}C$, $40^{\circ}C$, $50^{\circ}C$, and $60^{\circ}C$, respectively. Additionally, the enzyme $K_r$ values were 0.002, 0.054, 0.097, 0.184, and 0.341 $S^{-1}$ at $30^{\circ}C$, $35^{\circ}C$, $40^{\circ}C$, $50^{\circ}C$, and $60^{\circ}C$, respectively. The enzyme displayed a strong affinity to homocysteine, followed by methionine and cysteine when compared with non-S amino acids, confirming its potency against homocysteinuria-related diseases, and as an anti-cardiovascular agent and a specific biosensor for homocysteinuria. The enzyme showed its maximum affinity for homocysteine ($K_m$ 2.46 mM, $K_{cat}\;1.39{\times}10^{-3}\;s^{-1}$), methionine ($K_m$ 4.1 mM, $K_{cat}\;0.97{\times}10^{-3}\;s^{-1}$), and cysteine ($K_m$ 4.9 m M, $K_{cat}\;0.77{\times}10^{-3}\;s^{-1}$). The enzyme was also strongly inhibited by hydroxylamine and DDT, confirming its pyridoxal 5'-phosphate (PLP) identity, yet not inhibited by EDTA. In vivo, using Swiss Albino mice, the enzyme showed no detectable negative effects on platelet aggregation, the RBC number, aspartate aminotransferase, alanine aminotransferase, or creatinine titer when compared with negative controls.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.5
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• pp.509-514
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• 1994

A processing method for fermented paste of favorable flavor and texture using pen shell by-product was investigated. The pen shell by-product was homogenized with the addition of water and hydrolyzed with $5\%$ of Protin P(105 PU/g) at $55^{\circ}C$ for 1 hour. Flavor of the hydrolysate could be improved by thermal treatment at $100^{\circ}C$ for 40 minutes with $10\%$ of invert sugar. $2\%$ of agar-agar and $6\%$ of starch added to hydrolysate emulsified by $8\%$ of polyglycerol condensed ricinoleate(PGDR) were significantly effective for the improvement of rheological properties such as hardness, springiness and chewiness of the fermented paste. $15\%$ of table salt was finally added to the product of fermented pen shell paste. The contents of moisture, protein, lipid, carbohydrate and salinity of the product were $62.7\%,\;3.2\%,\;4.4\%,\;10.6\%\;and\;15.6\%$, respectively. The major free amino acids were glutamic acid, arginine, aspartic acid, leucine, lysine, glycine and alanine. The product was stable for the storage of 60 days at $23{\pm}3^{\circ}C$ on bacterial growth.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.196-200
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• 2002

In order to identify the feeding stimulants for flatfish, the feeding tests were conducted using some diets added the amino acids, nucleotides, betaine and TU and acid hydrolysates to basal diet formula, respectively, The feeding stimulant activities and synergistic effects of those compounds were evaluated by a bioassay method. The KH, a kind of acid hydrolysate, possessed a remarkable feeding stimulant activity. It's stimulant activities were increased up to the concentration of $1.05\%$ (w/v), and were independent of pH. The formulation of KH and glycine had a most synergistic effect, The feeding rate of diet with feeding stimulation was 1,4 fold than that of diet without one. The costs for optimum formulation of feeding stimulants were cheaper than some additives in diets. It suggest that the results can practically used in preparation of diet containing feeding stimulant effects for flatfish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.122-129
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• 2002

In order to elucidate a responsible mechanism for the development of the odor characteristics of cooked desirable flavoring materials such as crab and shrimp, shore swimming crab flesh were extracted with various solvents and resulting extracts were evaluated organoleptically after cooking. As a result, $80\%$ aqueous methanol extract (AME) was found to produce a cooked desirable flavoring odor. After dialysis of AME, outer dialyzate was fractionated by ionexchange column chromatography, and each of the fraction obtained was subjected to cooking, fellowed by organoleptic evaluation. The outer dialyzate fraction, acidic and amphoteric fraction produced a cooked crab-like odor, On the basis of the composition of $80\%$ AME, an artificial crab extract was prepared with pure chemicals. The artificial crab extract thus obtained closely resembled $80\%$ AME in respect of the cooked odor. To elucidate the role of individual components, the artificial extracts from which certain component alone or as group was omitted were subjected to organoleptic evaluation after cooking. All of neutral, acidic, basic, and sulfur containing amino acids and quarternary base compounds were involved in the development of the cooked crab-like odor. The cooked odor of artificial extract without addition of ribose was lacking in the characteristics of cooked crab odor, and phosphorus compound accelerated the development of the cooked crab-like odor.

• Korean Journal of Plant Tissue Culture
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• v.26 no.2
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• pp.121-126
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• 1999

Calli were induced from the petiole explants of Pimpinella brachycarpa on MS medium supplemented with 0.5 mg/L 2,4-D and 0.1 mg/L BA after four weeks of culture. Compact clusters of small and dense cells among these calli were selected and suspension-cultured as the source of embryogenic calli. When transferred to MS medium with 0.1 mg/L NAA, the suspension-cultured cells grew to embryogenic callus. Somatic embryos derived from these embryogenic calli developed into plantlets. The cDNA library was constructed in the embryogenic callus and in order to screen the cDNA library, these cDNAs were plated at a density 1.5 $\times$ 10^5 plaques per 15 cm petridish. Among 19 clones showing preferential hybridization with petiole HD-Zip gene, five clones were obtained after second screening. Four clones among them, were highly homologous to P. brachycarpa shoot-tip Phz4 gene, but one clone, Phc5 was about 1.5 kb which has an extra 163 bp to 5' upstream of Phz4. The Phc5 was 1,531 bp containing poly A tails of 18 bases. ATG start codon for Phc5, was located at position 284 with an open reading frame of 906 by which encodes a polypeptide of 302 amino acids. The Phc5 protein revealed that the polypeptides between 135 and 195 contain a homeodomain as the `leucine zipper' motif.

• Korean Journal of Food Science and Technology
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• v.33 no.2
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• pp.184-189
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• 2001

Comparative effects of gamma irradiation and methyl bromide (MeBr) fumigation on water-soluble components of small red bean and mung bean were investigated. The levels of soluble solid and reducing sugar of soaked water at $20^{\circ}C$ for 16 h definitely increased as irradiation dose increased, which was more apparent in small red bean than in mung bean. But, their levels of MeBr-fumigated sample showed a similar result to those of the control, except for soluble solid of small red bean. The pH of soaked water was insignificantly different among treatments. The decrease in lightness (L value) and the increases of redness (a value) and yellowness (b value) were remarkable as irradiation dose increased, which was more significant in fumigated samples. The ${\Delta}E$ values of fumigated sample showed almost equaled to those of 10 kGy in red bean and 30 kGy in mung bean, respectively. Gamma irradiation caused the increase in free amino acids of soaked water, that mainly consisted of asparagine, glutamic acid, and valine, while fumigation reduced their contents. The extractables in soaked water, such as soluble solid and reducing sugar, showed a highly positive correlation with irradiation dose applied.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.236-240
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• 2002

Characteristics of ostrich egg shell and optimal ashing conditions for preparation of calcium lactate were investigated. Average weight, girth, and length of ostrich egg shell with membrane (OESM) were 255.17 g, 39.50 cm, and 15.20 cm, respectively. Ostrich egg shell without membrane (OES) contained 0.35% moisture, 40.98% Ca as a maior mineral, 2.43% protein, and 235.0 mg/100 g of amino acids. Optimal ashing times for preparation of white-colored ashing powder from OES were 12 hr at $700^{\circ}C$, 80 min at 80$0^{\circ}C$, and 15 min at 90$0^{\circ}C$, respectively. These ashing conditions resulted in ashing powder with yields of 54.5~54.6% and color values of 97.26 ~97.51 for $L^{*}$, -0.30~-0.34 for $a^{*}$, and 0.63~0.98 for $b^{*}$. Ashing powders, from three different particle size ranges of OES, did not show significant differences in yield.eld.d.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.204-210
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• 2002

The quality characteristics and sensory evaluation of chungkookjang were investigated. The samples were prepared and fermented by the inoculation of Bacillus strains; B. subtilis, B. natto and B. licheniformis as a single starter, and mixed culture of B. natto and B. licheniformis on the industrialized model system. It was shown that microbial growth, protease activity, contents of amino-and ammonia-nitrogen and contents of organic acid were higher in B. subtilis inoculated sample, and were lower in B. licheniformis inoculated one. General quality characteristics of sample inoculated by mixed culture of B. natto and B. licheniformis took a middle position between each B. natto and B. licheniformis inoculated one. Fifty eight species of odor components were identified. Ethanol, 3-methyl-1-butanol, acetic acid, benzaldehyde and alkyl pyrazines were identified in all samples and most of other flavor components were strain specific. The contents of unpleasant smell components, alkyl pyrazines and benzaldehyde, were lower in B. licheniformis inoculated sample. The sensory evaluations showed that chungkookjang manufactured from mixed culture of B. natto and B.licheniformis was most acceptable. Therefore, results indicated that chungkookjang manufactured from mixed culture of B. natto and B. licheniformis induced better sensory quality than that of the control.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.8
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• pp.1390-1393
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• 2003

Measuring in vivo rate of bone collagen synthesis has so far been technically difficult and often subject to quite large errors. In the present study, bone collagen synthesis rate was measured using a precursor-product method, based on the exchange of $^2$$H_2O$ into amino acids. Mass isotopomer abundance in hydroxyproline from bone collagen was analyzed by gas chromatography/mass spectrometry. The $^2$$H_2O$ labeling protocol consisted of an initial intraperitoneal injection of 99.9% $^2$$H_2O$, to achieve approximately 2.5% body water enrichment followed by administration of 4% $^2$$H_2O$ in drinking water for 9 weeks. Body $^2$$H_2O$ enrichments were stable at 2.7 ∼ 3.0% over labeling Period. In growing rats, the fractional synthesis rate ( $k_{s}$) of bone collagen was 0.066 $\pm$ 0.049 w $k^{-1}$ . The unique features of stable $^2$$H_2O$ pools and label incorporation allowed the precursor-product approach to be used for measuring bone collagen synthesis rate..

• Journal of Ginseng Research
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• v.40 no.1
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• pp.28-37
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• 2016

Background: Panax ginseng cannot be cultivated on the same land consecutively for an extended period, and the underlying mechanism regarding microorganisms is still being explored. Methods: Polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) and BIO-LOG methods were used to evaluate the microbial genetic and functional diversity associated with the P. ginseng rhizosphere soil in various cultivation ages and modes. Results: The analysis of microbial diversity using PCR-DGGE showed that microbial communities were significantly variable in composition, of which six bacterial phyla and seven fungal classes were detected in P. ginseng soil. Among them, Proteobacteria and Hypocreales dominated. Fusarium oxysporum, a soilborne pathogen, was found in all P. ginseng soil samples except R0. The results from functional diversity suggested that the microbial metabolic diversity of fallow soil abandoned in 2003was the maximum and transplanted soil was higher than direct-seeding soil and the forest soil uncultivated P. ginseng, whereas the increase in cultivation ages in the same mode led to decreases in microbial diversity in P. ginseng soil. Carbohydrates, amino acids, and polymers were the main carbon sources utilized. Furthermore, the microbial diversity index and multivariate comparisons indicated that the augmentation of P. ginseng cultivation ages resulted in decreased bacterial diversity and increased fungal diversity, whereas microbial diversity was improved strikingly in transplanted soil and fallow soil abandoned for at least one decade. Conclusion: The key factors for discontinuous P. ginseng cultivation were the lack of balance in rhizosphere microbial communities and the outbreak of soilborne diseases caused by the accumulation of its root exudates.