• KSBB Journal
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• v.20 no.5 s.94
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• pp.376-382
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• 2005

Avermectin (AVM) $B_{1a}$ produced by Streptomyces avermitilis via polyketide pathway is a secondary metabolite with powerful anthelmintic and insecticidal activities, thus being used as an efficient agent in the field of agriculture and animal health. It has been reported that a precursor for AVM $B_{1a}$ biosynthesis was isoleucine and the biosynthetic pathway of AVM $B_{1a}$ was closely similar to that of fatty acid. Based on understanding of the biosynthetic pathway of AVM $B_{1a}$, we intended to screen various mutants resistant against O-methyl threonine (OMT), an isoleucine-anti metabolite, and/or mutants resistant against p-fluoro phenoxy acetic acid (pFAC), an inhibitor of fatty acid biosynthesis. It was inferred that these mutants could produce AVM $B_{1a}$ more efficiently, due to the acquired capability of not only overproducing isoleucine intracellularly but also channelling metabolized carbon-sources into the polyketide pathway, thus leading to enhanced biosynthesis of AVM $B_{1a}$. The resulting mutant (PFA-1 strain) resistant against 100 ppm of pFAC was able to produce approximately 42 fold higher amount of AVM $B_{1a}$ compared to the parallel mother strain (4,200 vs. 100 units/l). In addition, through the process of continuous strain improvement program carried out by gradually increasing the OMT concentration, it was possible to obtain a more attractive mutant with greater AVM $B_{1a}$ production capacity (9,000 units/l). Notable was that significantly higher producer (12,000 units/l) could be selected through further screening of the resistant mutants, this time, to even higher concentration of PFAC. Meanwhile, through the analysis of AVM Bla production histograms (i.e., number of strains according to their AVM $B_{1a}$ biosynthetic ability) for the earlier strains in comparison with the high producers having the characteristics of resistance to OMT and pFAC, it was found that production stability of the high-yielding producers were remarkably improved, as demonstrated by the fact that larger proportion of the mutated strains had greater capability of AVM $B_{1a}$ biosynthesis ($71\%$ in the range between 5,000 and 7,000 units/L; $47\%$ in the range between 6,000 and 7,000 units/l). Based on these consequences, it was concluded that the rational screening strategy based on the understanding of the biosynthetic pathway of AVM $B_{1a}$ was very effective in obtaining high-yielding mutants with the features of enhanced production stability.

• Journal of Applied Biological Chemistry
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• v.56 no.3
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• pp.157-163
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• 2013

Cultured products (callus and exopolysaccharide) were obtained from suspension culture of Aloe vera callus, and the extracts of callus were further prepared with cold water or 60% ethanol solution. The ethanol extract of callus (AC) and exopolysaccharide (ACP) of 10 mg/mL exhibited the relatively higher suppression activity of 43.2-52.1% against hyaluronidase activity. Thus, their anti-inflammatory effects were further investigated using animal cell (Raw 264.7) in vitro. Though AC shows a slight suppression effect of cell survival rate (97%) using MTT assay in the presence of $400{\mu}g/mL$ AC- dimethyl sulfoxide (DMSO), cell growth promotion was observed in the other samples of lower levels. It indicates that the ethanol extract of Aloe callus rarely affect cell survival rate in the ranges ($200-400{\mu}g/mL$) used in the study. Using Griess reagent, the suppression of NO production by the aloe callus extract was analyzed by measuring the amount of the nitrite produced in Raw 264.7 culture activated by lipopolysaccharide (LPS). As a result, supplementation of AC-distilled water (DW) and AC-DMSO produced higher levels of NO than the positive control LPS. However, the NO suppression effect by ACP-DW was so intense that lower amount ($80-100{\mu}g/mL$) suppressed NO production to the level of the control. The effect was attributed to the expression of the iNOS. Then, Raw 264.7 cells were stimulated with the LPS and expression of COX-2 protein level was analyzed depending on the Aloe suspension culture product treatment. The results showed that the ACP-DW supplemented medium did not express COX-2 by itself, and LPS stimulated COX-2 expression was slightly decreased. On the other hand, realtime-PCR analysis of the expression of inflammatory cytokine showed that IL-$1{\beta}$ and TNF-${\alpha}$ expression was highly suppressed in the ACP- distilled water supplemented medium.

• Journal of Animal Science and Technology
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• v.45 no.1
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• pp.69-78
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• 2003

This experiment was carried out to evaluate the value of total mixed fermentation feeds(TMFF) as completely mixed ration and to observe the effect of various kinds of TMFF on the palatability, feed intake, and milk performance in Holstein cows. The dry matter (DM) content of TMFF used in the experiment was 23.98-28.42% range, and CP, TDN, ADF and NDF were 16.2${\sim}$19.2%, 58.3-65.1%, 34.4-39.6% and 46.9${\sim}$49.9% levels, respectively. The relative feed value (RFV) in rape-, alfalfa-, grass-, oat-, corn-TMFF groups were 138.6, 133.9, 116.5, 111.8, 111.4 and 108.1, respectively. Among these groups, RFV of rye-TMFF group was lowest. Dry matter disappearance(DMD) showed 0.8${\sim}$.9% to the all kinds of TMFF groups. The pH was 3.89${\sim}$.87 and $NH_3$-N concentration was 6.93-8.66 mg/$d\ell$. The acetic acid concentration in the raw material of TMFF showed low level of 0.19${\sim}$0.57%, lactic acid showed high level of 1.17${\sim}$3.21% and butyric acid was very high as 0.03${\sim}$0.32%. Therefore, these results provide evidence that the quality of TMFF was not so bad. In the daily fresh matter intake on the alfalfa-, grass-, rape-, corn-, oats- and rye-TMFF were showed 62.85, 60.48, 58.04, 57.11, 54.61 and 45.74 kg respectively. All TMFF showed high palatability as daily dry matter intake of 1.95 to 2.90% by body weight of experimental cows. Body condition score(BCS) was gradually increased in during 60 days of the experiment term. Average daily gain(ADG) showed about 140.0${\sim}$326.7g. In alfalfa-TMFF group, the ADG was higher than in the other groups (p<0.05). Also, the increase in BCS was observed in grass-TMFF group (3.07 to 3.34) and rye-TMFF group was decreased in 3.07 to 3.34 (p<0.05). The milk yield appropriately showed a range of 16.16${\sim}$18.95 kg in all groups. Among these groups, alfalfa-TMFF group was highest(P<0.05). Average milk fat contents showed high levels of 4.06${\sim}$4.79% and the level was high in order of rape-, grass-, corn-, alfalfa-, rye- and oats-TMFF. Milk protein was highest in forage-TMFF and level of lactose in milk was approximately 4.56% in overall groups. Solid non fat(SNF) and total solid(TS) contents were 8.75% and 12.8%, respectively. However, milk composition was not significantly affected by TMFF.

• Journal of radiological science and technology
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• v.30 no.3
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• pp.205-212
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• 2007

To evaluate the feasibility and efficacy of a pulsatile aortic aneurysm phantoms for in-vitro study. The phantoms consisted of a pulsating motor part(heart part) and an aortic aneurysm part, which mimicked true physiologic conditions. The heart part was created from a high-pressured water pump and a pulsatile flow solenoid valve for the simulation of aortic flow. The aortic aneurysm part was manufactured from paper clay, which was placed inside a acrylic plastic square box, where liquid silicone was poured. After the silicone was formed, the clay was removed, and a silicone tube was used to connect the heart and aneurysm part. We measured the change in pressure as related to the opening time(pulse rate, Kruskal-Wallis method) and pressure before and after the stent-graft implantation(n = 5, Wilcoxon's signed ranks test). The changes in blood pressures according to pulse rate were all statistically significant(p<0.05). The systolic/diastolic pressures at the proximal aorta, the aortic aneurysm, and the distal aorta of the model were $157.80{\pm}1.92/130.20{\pm}1.92$, $159.40{\pm}1.14/134.00{\pm}2.92$, and $147.20{\pm}1.480/129.60{\pm}2.70\;mmHg$, respectively, when the pulse rate was 0.5 beat/second. The pressures changed to $161.40{\pm}1.34/90.20{\pm}1.64$, $175.00{\pm}1.58/93.00{\pm}1.58$, and $176.80{\pm}1.48/90.80{\pm}1.92\;mmHg$, respectively, when the pulse rate was 1.0 beat/second, and $159.40{\pm}1.82/127.20{\pm}1.48$, $166.60{\pm}1.67/138.00{\pm}1.87$, and $161.00{\pm}1.22/135.40{\pm}1.67\;mmHg$, respectively, when it was 1.5 beat/second. When pulse rate was set at 1.0 beat/second, the pressures were $143.60{\pm}1.67/90.20{\pm}1.64$, $147.20{\pm}1.92/84.60{\pm}1.82$, and $137.40{\pm}1.52/88.80{\pm}1.64\;mmHg$ after stent-graft implantation. The changes of pressure before and after stent-graft implantation were statistically significant(p<0.05) except the diastolic pressures at the proximal(p =1.00) and distal aorta(p=0.157). The aortic aneurysm phantoms seems to be useful for the evaluation of the efficacy of stent-graft before animal or clinical studies because of its easy reproducibility and ability to display a wide range of pressures.

• The Korean Journal of Food And Nutrition
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• v.24 no.3
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• pp.367-375
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• 2011

For this study, Korean-type Koumiss was made by the fermentation of mixed cultures, in which yeast, Kuyveromyces, and microflora, Streptococcus thermophiles and Lactobacillus bulgaricus, were inoculated into 10% skimmed milk with added whey powder(control: A, 2%: B, 4%: C, 6%: D, and 8%: E). Fat, protein, lactose, titratable acidity, pH, the number of lactic acid bacteria, the number of yeast, alcohol content, volatile fatty acids, volatile free amino acids and minerals were measured in the products. The results were as follows: As the dosage of whey powder increased, fat increased from 0.74% in the control to 2.30% in sample E, protein increased from 2.95% in the control to 4.39% in sample E and lactose increased from 3.10% in the control to 7.43% in sample E. Titratable acidity and pH increased gradually. The number of lactic acid bacteria increased from $10^9\;cfu/m{\ell}$ in the control to $3.8{\times}10^9\;cfu/m{\ell}$ in sample E, and the number of yeast increased from $6.1{\times}10^7\;cfu/m{\ell}$ in the control to $1.65{\times}10^8\;cfu/m{\ell}$ in sample E, according to the increase of whey powder content. For alcohol content, the average values were 0.863%, 0.967%, 0.890%, 1.290%, and 1.313% for the control and samples B, C, D, and E, respectively. As the dosage of whey powder increased, alcohol content showed a tendency to gradually increase. The average alcohol content of E was 1.313 and this was higher than the alcohol content of Kazahstana-type Koumiss with 1.08%. Sixteen types of free amino acids were detected. Glycine was the lowest in the control at $0.38mg/m{\ell}$ and sample E contained $0.64mg/m{\ell}$. Histidine was also low in the control at $0.42mg/m{\ell}$ and sample E contained $0.65mg/m{\ell}$. On the other hand, glutamic acid was highest at $4.13mg/m{\ell}$ in the control whereas sample E had $6.96mg/m{\ell}$. Proline was also high in the control at $1.71mg/m{\ell}$ in control, but E contained $2.80mg/m{\ell}$. Aspartic acid and leucine were greater in sample E than in the control. For volatile free fatty acids, content generally had a tendency to increase in the control, and samples B, C, D, and E. Content of acetic acid gradually increased from $12,661{\mu}g/100m{\ell}$ in the control to $37,140{\mu}g/m{\ell}$ in sample E. Butyric acid was not detected in the control and was measured as $1,950{\mu}g/100m{\ell}$ in sample E. Caproic acid content was $177{\mu}g/100m{\ell}$ in the control and $812{\mu}g/100m{\ell}$ in sample E, and it increased according to the increase of whey powder content. Valeric acid was measured in a small amount in the control as $22{\mu}g/100m{\ell}$, but it was not detected in any other case. Mineral contents of Ca, P, and Mg increased from 1,042.38 ppm, 863.61 ppm, and 101.28 ppm in the control to 1,535.12 ppm, 1,336.71 ppm, and 162.44 ppm in sample E, respectively. Na content was increased from 447.19 ppm in the control to 1,001.57 ppm in sample E. The content of K was increased from 1,266.39 ppm in the control to 2,613.93 ppm in E. Mineral content also increased with whey powder content. In sensory evaluations, the scores increased as whey powder content increased. Flavor was lowest in the control with 6.3 points and highest in E with 8.2 points. Body and texture were highest at 4.2 points in the control, which did not have added whey powder. In the case of appearance, there were no great differences among the samples.