• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.731-734
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• 2001

An efficient fermentation strategy for the high level production of ultra-high-molecular weight poly(3-hdyroxybutyrate) (PHB) was developed. Although the cell and PHA concentrations obtained by flask cultures at different initial pH (6.0 or 6.9) were almost same level, the molecular mass of PHB produced were quite different along with the initial pH. When a recombinant Escherichia coli XL1-Blue harboring pJC2 containing the Alcaligenes latus PHB biosynthesis genes was cultivated in flask culture (pH 6.0), the PHB having a very high molecular weight of 22 MDa could be produced while only below 1 MDa at initial pH 6.9. The ultra-high-molecular weight PHB could be synthesized to high concentration of 89.8 g/L resulting in the PHB productivity of 2.07 g/L-h by simple fed-batch culture. In this study, we report that PHB having various molecular mass can be produced by employing metabolically engineered E. coli strains harboring the plasmids of different copy numbers containing the A. latus phbCAB genes.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.270-270
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• 2012

Low temperature atmospheric pressure plasmas (APPs) have been known to be effective for living cell inactivation in the water [1]. Many earlier research found that pH level of the solution was changed from neutral to acidic after plasma treatment. The importance of the effect of acidity of the solution for cell treatments has already been reported by many experiments. In addition, several studies have demonstrated that the addition of a small amount of oxygen to pure helium results in higher sterilization efficiency of APPs [2]. However, it is not clear yet which species are key factors for the cell treatment. To find key factors, we used GMoo simulation. We elucidate the processes through which pH level in the solution is changed from neutral to acidic after plasma exposure and key components with pH and air variation with using GMoo simulation. First, pH level in a liquid solution is changed by He+ and He(21S) radicals. Second, O3 density decreases as pH level in the solution decreases and air concentration decreases. It can be a method of removing O3 that cause chest pain and damage lung tissue when the density is very high. H2O2, HO2 and NO radicals are found to be key factors for cell inactivation in the solution with pH and air variation.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.11
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• pp.1655-1661
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• 2007

Prolyl 4-hydroxylase (P4H) plays a central role in collagen synthesis by catalyzing the hydroxylation of the proline residue in the X-Pro-Gly amino acid sequence, and controls the biosynthesis of collagen that influences overall meat quality. In order to verify expression level of the catalytic ${\alpha}$ subunit of P4H, a 2.7 kb clone of the ${\alpha}$ subunit gene for P4H was selected from a cDNA library prepared from the muscular tissue of Sancheong berkshire pigs, and the whole gene sequence was determined. As expression level of the ${\alpha}$ subunit of P4H differed between tissues of pigs, we intended to assess more precisely the level of ${\alpha}$-subunit expression between tissues of Sancheong Berkshire pigs by using RT-PCR. Muscular and adipose tissues were taken from each pig grouped by growth stage (weighing 60, 80, and 110 kg) of Yorkshire and Sancheong Berkshire pigs, and the expression levels of the ${\alpha}$-subunit of P4H were examined. Since there were significant differences in the expression level with respect to variation in growth stage (p<0.01), an attempt was made to identify any influences of pig species and tissue variation. The muscular and adipose tissues of pigs weighing 110 kg showed higher expression levels than pigs weighing 60 kg and 80 kg. In general, significantly higher expression levels were found in muscular than in adipose tissue. The expression levels in Sancheong Berkshire were significantly higher than in Yorkshire pigs (p<0.01 or p<0.05). Since expression level of the ${\alpha}$-subunit of P4H affects the activity of P4H and is connected to the biosynthesis of collagen and increased collagen can improve meat texture, this finding may explain why meat quality of the Sancheong Berkshire pig is acclaimed in Korea. Given the higher expression levels of the ${\alpha}$-subunit gene in adipose than in muscular tissue, and also in the heavier pigs, more intensive studies are required to assess the correlation between expression level of the ${\alpha}$ subunit gene and overall meat quality.

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.292-298
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• 2018

In this study, Ascidian shell pigment was extracted, first using a 100.0 % ethanol solvent, proceeding with the dilution of it with DMSO (Dimethyl sulfoxide). The extracted pigment was evaluated to verify the stability. The absorbance of light have been evaluated according to pH levels and using the color-difference meter. As a result, it could be seen that absorbance and chromaticity ${\pm}a$ values were most stable at a pH level of 7.0 By keeping the sample at a pH level of 3.0, it could be observed that the absorbance and the chromaticity ${\pm}a$ values were decreased. Based on this observation, it can be deduced that the discoloration of the pigment can be prevented if kept at a neutral pH level. When antioxidants were added, the absorbance of the pigment increased, and the best effects could be seen in the ${\alpha}-tocopherol$ and glutathione samples.

• The Korean Journal of Food And Nutrition
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• v.25 no.1
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• pp.64-68
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• 2012

It has been suggested that Helicobacter pylori(H. pylori) infections can promote the development and progression of gastric cancer through the modulation of cell cycle regulators such as $p27^{Kip1}$ and Skp2. $p27^{Kip1}$ is a cyclin-dependent kinase (CDK) inhibitor that blocks the G1/S transition necessary for cell cycle progression. Skp2 is a component of the ubiquitin ligase complex called $SCF^{Skp2}$(SKP1-Cullin-F-box), which specifically binds and promotes the degradation of $p27^{Kip1}$. A low level of $p27^{Kip1}$ and a high level of Skp2 have been reported in many types of cancers, including gastric cancer. In addition, a decrease in $p27^{Kip1}$ has been reported in H. pylori-infected specimens. However, data on Skp2 in H. pylori infections are limited. This study examines the changes in the status of Skp2 in H. pylori-infected gastric epithelial AGS cells. For this, we stimulated AGS cells with H. pylori(NCTC 11637) at the ratio of 300:1(bacterium:cell) for 6 hours. The results of an immunoprecipitation analysis, followed by a western blot, indicate that the interaction between Skp2 and 14-3-3 was elevated 3 hours after the H. pylori treatment. In addition, there was an increase in cytoplasmic Skp2 after 3 hours, whereas there was no change in the nuclear level. Since it has been reported that interaction with 14-3-3 and the subsequent cytoplasmic translocation of Skp2 can increase its protein stability, increases in the interaction with 14-3-3 and the cytoplasmic Skp2 after the H. pylori treatment can increase the level of Skp2 in AGS cells. This phenomenon may explain, at least to some extent, the mechanism underlying the relationship between H. pylori infections and gastric carcinogenesis.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.1
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• pp.83-92
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• 2014

This experiment was conducted to evaluate the effects of dietary CP levels in gestation under equal lysine content on reproductive performance, blood metabolites and milk composition of gilts. A total of 25 gilts ($F_1$, Yorkshire${\times}$Landrace) were allotted to 4 dietary treatments at breeding in a completely randomized design, and fed 1 of 4 experimental diets containing different CP levels (11%, 13%, 15%, or 17%) at 2.0 kg/d throughout the gestation. Body weight of gilts at 24 h postpartum tended to increase linearly (p = 0.09) as dietary CP level increased. In lactation, backfat thickness, ADFI, litter size and weaning to estrus interval (WEI) did not differ among dietary treatments. There were linear increases in litter and piglet weight at 21 d of lactation (p<0.05) and weight gain of litter (p<0.01) and piglet (p<0.05) throughout the lactation as dietary CP level increased. Plasma urea nitrogen levels of gilts in gestation and at 24 h postpartum were linearly elevated as dietary CP level increased (p<0.05). Free fatty acid (FFA) levels in plasma of gestating gilts increased as dietary CP level increased up to 15%, and then decreased with quadratic effects (15 d, p<0.01; 90 d, p<0.05), and a quadratic trend (70 d, p = 0.06). There were no differences in plasma FFA, glucose levels and milk composition in lactation. These results indicate that increasing dietary CP level under equal lysine content in gestation increases BW of gilts and litter performance but does not affect litter size and milk composition. Feeding over 13% CP diet for gestating gilts could be recommended to improve litter growth.

• Journal of Life Science
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• v.27 no.7
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• pp.826-833
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• 2017

The rising concentration of atmospheric carbon dioxide is causing ocean acidification and global warming. The seahorse is an important species in marine ecosystems and fishery markets, however, their populations have recently decreased due to ocean acidification. As a result, we examined changes in the physiological responses of the spotted seahorse Hippocampus kuda when it was exposed to acidic sea water (pH 6.0, 6.5, and 7.0) and normal seawater (pH 8.0 as the control) over a period of 15 days. As the pH decreased, the seahorses' body weight and length also decreased. Components in body of ash, the crude lipids and crude proteins also differed significantly with changes in pH, due to stress caused by the seahorses' exposure to the acidic water conditions. The superoxide dismutase levels were significantly lower in the pH 6.0 and 6.5 groups than they were in the pH 7.0 and pH 8.0 groups. However, the catalase and glutathione levels were significantly higher in the acidic sea water groups. We suggest that decreasing the pH level of rearing water induces a stress response in H. kuda, damaging their ability to maintain their homeostasis and energy metabolism. Antioxidant enzymes are generally sensitive to acidic stress; in this study, the antioxidant activity was significantly affected by the pH level of the rearing water. These results indicate that physiological stress, induced by exposure to acidification, induces an antioxidant reaction, which can reduce general components in the body and the growth of H. kuda.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.51-58
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• 2008

Four ruminally cannulated Nili-ravi buffalo bulls were used in a $4{\times}4$ Latin Square design to determine the influence of varying levels of ruminally degradable protein (RDP) on ruminal characteristics, digestibility, blood pH, blood urea nitrogen (BUN) and nitrogen (N) balance. Four isonitrogenous and isocaloric diets were formulated (NRC, 2001). The control diet contained 50% RDP. The medium (MRDP), high (HRDP) and very high (VHRDP) ruminally degradable protein diets had 66, 82 and 100% RDP, respectively. Increasing the level of dietary RDP resulted in a linear decrease in ruminal pH. A quadratic effect of RDP on ruminal pH was also observed with quadratic maxima at the 66% RDP diet. Dietary RDP had a quadratic effect on total bacterial and protozoal count with maximum microbial count at the 82% RDP diet. Increased microbial count was due to increasing level of ruminal ammonia nitrogen ($NH_3-N$). Increasing dietary RDP resulted in a linear increase in dry matter digestibility. Provision of an adequate amount of RDP caused optimum microbial activity, which resulted in improvement in DM digestibility. Increasing the level of dietary RDP resulted in a linear decrease in crude protein (CP) and neutral detergent fiber digestibility. Blood pH remained unaltered across all diets. A linear increase in ruminal $NH_3-N$ and BUN was noted with increasing level of dietary RDP. The increase in BUN was due to increased ruminal $NH_3-N$ concentrations. A positive N balance was noted across all diets. The results are interpreted to suggest that buffalo bulls can utilize up to 82% RDP of total CP (16%) with optimum results.

• Preventive Nutrition and Food Science
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• v.15 no.4
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• pp.287-296
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• 2010

This study was designed to investigate the influence of the pH and enantiomer on the antioxidant activity of Maillard reaction mixture solution in model systems. The loss of glucose in MRPs did not show different characteristics for the different amino acid enantiomers; however, the concentration of glucose decreased as the pH levels increased. The enolization of sugars was observed in all MRP samples according to increase of pH levels. In addition, D-amino acids were detected in L-amino acid systems and L-amino acids could also be observed in D-amino acid systems. Formation of the isomer was the highest in the Glc/L-Lys system. The browning development increased as pH levels increased; however, browning development did not show different characteristics based on the use of L- versus D-isomers of the same amino acid. The L- and D-isomers show different absorption values in the UV-Vis spectra, but the absorption patterns display a similar shape. The antioxidant activities of MRPs derived from the Glc/Gly, Glc/L-Asn and Glc/D-Asn systems at pH 7.0 were greater compared to those of pH 4.0 and pH 10.0. The antioxidant activities of MRPs derived from the Glc/L-Lys and Glc/D-Lys systems decreased as the pH increased. In addition, the results show that the MRPs derived from the D-isomers have similar antioxidant activities as those from L-isomer. Therefore, the MRPs have the different antioxidant activities on the basis of the pH level, but not on the basis of different amino acid enantiomers.

• Korean Journal of Poultry Science
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• v.24 no.4
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• pp.199-206
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• 1997

In this experiment, three kinds of autoclaved poultry by-product meals, P1 (head+feet+viscera), P2(P1+blood), and P3(P2+feathers), mixed as to the yielding ratios, and three kinds of autoclaved hatchery by-products meals, H1 (male d-old chicks of egg strain), H2(dead embryos ＆ infertile eggs), and H3(H1+H2, 2:1) were formulated into the layer diets each at 5％ level, respectively, and compared with the control diets(C) containing fishmeal on laying performances and egg qualifies. The egg production, average egg weight, feed intake and feed conversion were not significantly affected by the poultry or hatchery by-product meals. The egg shell qualities, such as the egg specific gravity, egg breaking strength and shell thickness, were not different among treatments. The egg yolk colour was improved by the feeding of hatchery by-products meals (P<0.05). In conclusion, pultry and hatchery by-product meals could be used in layer diets without any adverse effects on laying performances to substitute for fishmeal at about 5％ level.