• 한국안광학회지
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• 제15권4호
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• pp.347-353
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• 2010

목적: 소프트콘택트렌즈 관리용액에 의한 balafilcon A 재질의 실리콘 하이드로겔렌즈에 부착된 지방 침전물 제거효과를 비교하였다. 방법: Balafilcon A 재질의 실리콘 하이드로겔렌즈를 실험실 조건에서 oleic acid, oleic acid methyl ester, cholesterol이 포함된 식염수에 담가 24시간 동안 오염시켰다. 오염된 콘택트렌즈는 식염수로 헹구어준 후 계면활성세척액, 알콜 성분이 포함된 세척액 및 다목적용액으로 각각 세척하였고, 반복적인 오염과 세척효과를 관찰하기 위해서는 오염과 세척과정을 14회 반복하였다. 초음파의 지방침전물 세척 효과를 관찰하기 위하여 오염된 렌즈에 초음파처리를 한 후 처리하지 않은 렌즈와 비교하였다. 지방침전물은 methanol:chloroform (1:1, v/v) 용액으로 추출하고 고성능액체크로마토그래피로 분석하여 정량하였다. 결과: 실리콘 하이드로겔렌즈의 지방세척효과는 알콜성분을 함유한 세척액이 계면활성세척액 및 다목적용액보다 높았으며, 초음파를 함께 처리해준 경우에는 세척 효과가 상승하였다. 콘택트렌즈 관리용액으로 세척한 후에도 지방침전물은 완전히 제거되지 않아 오염과 세척을 반복한 경우 지방 침전물의 양은 지속적으로 증가하였다. 결론: 실리콘 하이드로겔렌즈에 부착되는 지방 침전물에 대한 소프트 콘택트렌즈용 관리용액의 세척효과는 만족할 수준에 미치지 못하기 때문에 실리콘 하이드로겔렌즈의 지방 침전물 제거에 적합한 세척액의 개발이 필요할 것으로 사료된다.

• 생명과학회지
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• 제23권7호
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• pp.863-868
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• 2013

Bacillus sp. HY-20균주 유래 endoxylanase를 코드하는 XylP 유전자를 효모에서 발현시키기 위해 두 개의 발현 플라스미드 pG-xylP와 pGMF-xylP를 구축하였다. 이들 플라스미드는 endoxylanase의 분비발현을 위해 각각 다른 분비서열인 XylP 유전자의 자체 분비서열(XylP s.s)과 최적화된 $MF{\alpha}$ 분비서열($MF{\alpha}_{opt}$ s.s)을 가지고 있으며, S. cerevisiae SEY2102와 FY833균주에 형질전환되어 그 분비활성이 비교 조사되었다. 재조합 endoxylanase는 분비발현시스템과 숙주세포에 따라 23.7~70.1 unit/ml의 활성으로 효모 세포에서 성공적으로 발현되었고, 그 중 SEY2102/pGMF-xylP 형질전환주를 이용해 baffled-flask 배양을 실시한 결과 최대 88.1 unit/ml의 endoxylanase 활성을 보임을 확인하였다. 대부분의 재조합 endoxylanase는 세포 외 분획에 효율적으로 분비 생산되었으며, $MF{\alpha}_{opt}$ 분비서열이 XylP 유전자의 자체 분비서열보다 endoxylanase를 더 효율적으로 분비시킴을 확인할 수 있었다. 그러므로 본 연구에서 개발된 발현시스템은 효모를 숙주세포로 하여 많은 양의 세포 외 endoxylanase의 생산을 가능하게 하고, 바이오에탄올 생산 및 산업적 응용에도 유용하게 사용 될 수 있으리라 기대된다.

• Journal of Microbiology and Biotechnology
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• 제15권4호
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• pp.887-890
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• 2005

To evaluate the hepatoprotective activity of lactic acid bacteria, their effects on tert-butylperoxide (t-BHP)-induced hepatotoxicity in mice were measured. When lactic acid bacteria at doses of 0.5 and 2 g (wet weight)/kg were orally administered to mice with t-BHP-induced liver injury, these bacteria significantly inhibited the increase of plasma alanine aminotransferase and aspartate aminotransferase activities by $17-57\%$ and $57-66\%$ of the t-BHP control group, respectively. However, these lactic acid bacteria did not protect cytotoxicity induced by t-BHP against HepG2 cells. The inhibitory effects of these lactic acid bacteria at a dose of 15 g/kg were comparable with that of diphenyl dimethyl bicarboxylate at a dose of 0.2 g/kg, which has been used as a commercial hepatoprotective agent. Among these lactic acid Jacteria, Bifidobacterium longum HY8001 exhibited the most potent hepatoprotective effect. These orally administered lactic acid bacteria inhibited liver lipid peroxidation on t-BHP-induced hepatotoxicity of mice. We suggest that lactic acid bacteria may be an effective agent against liver injury.

• 유공압시스템학회논문집
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• 제5권4호
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• pp.17-25
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• 2008

This study presents an analytical model of the pneumatic circuit of an air suspension system to analyze the characteristics of vehicle height control. The analytical model was developed through the co-simulation of Simulink(air spring) and HyPneu(pneumatic circuit). Variant effective area of air spring and flow coefficients of pneumatic valves were estimated experimentally prior to the system test, and utilized in simulation. One-comer test apparatus was established using the components of commercial air suspension products. The results of simulation and experiment were so close that the proposed analytical model in this study was validated. However the frictional loss of conduit and heat dissipation which were ignored in this study need to be considered in future study. As an application example of proposed analytical model, an alternative pneumatic circuit of air suspension to conventional WABCO circuit was evaluated. The comparison of simulation results of WABCO circuit and alternative circuit show that proposed analytical model of co-simulation in this study is useful for the study of pneumatic system of automotive air suspension.

• 생명과학회지
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• 제28권2호
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• pp.187-194
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• 2018

표고버섯으로부터 유래한 eritadenine (EA)은 혈중 low density lipoprotein (LDL), triglyceride (TG), phospholipid를 감소시키는 물질이다. 최근 저희 연구팀은 in vitro 연구에서 EA가 angiotensin converting enzyme (ACE)의 활성을 저해함을 밝혔다. 본 연구에서는 EA와 EA 함유한 표고버섯균사체 고체배양 효소추출물(EA-LEMCEE)이 본태성 고혈압 쥐 SHR의 혈압을 낮추었음을 보고한다. EA 및 EA-LEMSCEE는 인체 탯줄 혈관내피세포 EA.hy926 세포의 ACE 활성을 억제하였다. EA-LEMSCEE는 SHR의 수축기 및 이완기 혈압을 Control 처리구에 비해 유의성 있게 낮추어 처리 5주에는 Positive control인 captopril (CP) 처리와 비슷한 혈압감소 효과를 나타내었다. EA-LEMCE는 LEMSCEE에 비해 수축기 및 이완기 혈압을 감소시켰지만 유의성은 없었다. EA- LEMSCEE는 renin과 ACE 활성을 Control 처리에 비해 유의성 있게 억제하였고, angiotensin II (Ang II) 함량을 감소시켜, 처리 5주 후에 이러한 CP의 효과와 유사하였다. 또한 EA-LEMCEE는 LEMCEE에 비해 유의성 있게 renin 및 ACE 활성을 억제하였고 및 Ang II 함량을 감소시켰다. 이와 같은 결과는 EA 및 EA-LEMCEE는 본태성 고혈압 SHR의 renin과 ACE 활성을 억제하여 혈압을 낮추었고, EA 및 EA-LEMSCEE는 인체 고혈압을 낮출 수 있음을 의미한다.

• 한국축산식품학회지
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• 제32권1호
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• pp.13-17
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• 2012

Two experiments were conducted to investigate the dietary effect of chlorella vulgaris on egg production and lutein incorporation into chicken eggs. In Exp. 1, a total of three hundred, 70 wk-old Hy-Line brown layers were divided into six groups with five replicates and fed each experimental diet (corn-SBM based control diet and diets with 0.1, 0.3 or 0.5% chlorella powder and with 0.8 or 2.4% chlorella cultured media) for 6 wk, respectively. The egg production in the groups fed diets containing the chlorella powder and chlorella cultured media were higher than that of the control group (p<0.001). As dietary chlorella levels increased, the yolk color linearly increased. However, there were no significant differences in egg-shell qualities. The layers fed diet with 2.4% chlorella cultured media showed the highest Haugh unit value. In Exp. 2, a total of one hundred-eight 80 wk-old Hy-Line brown layers were assigned into four groups with three replicates per group (9 birds per replicate). The birds were fed one of four experimental diets (0, 0.5, 1.0 or 2.0% chlorella powder) for 4 wk, followed by a 14 d feeding of a withdrawal diet devoid of chlorella powder. At 2 wk, the lutein greatly increased with increasing levels of chlorella powder in birds fed diets containing more than 1%. The maximum incorporation of lutein into eggs was reached after 2 or 3 wk of feeding diets with chlorella powder. After a 7 d withdrawal, the lutein contents of egg yolks in the groups fed diets with more than 1% chlorella powder were still higher than that of control group (p<0.05). No significant differences in the lutein levels were found among groups after a 14 d withdrawal period. These results indicated that the use of chlorella in layer diets was effective in improving egg production and egg quality and for the production of lutein fortified eggs.

• Journal of Microbiology and Biotechnology
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• 제16권11호
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• pp.1753-1759
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• 2006

Paenibacillus sp. HY-8 isolated from the digestive tracts of the longicorn beetle, Moechotypa diphysis, produced an extracellular endoxylanase with a molecular weight of 20 kDa estimated by SDS-PAGE. The xylanase was purified to near electrophoretic homogeneity from the culture supernatant after ammonium sulfate precipitation, gel filtration, and ionexchange chromatography. The purified xylanase exhibited the highest activities at pH 6.0 and $50^{\circ}C$. The $K_m\;and\;V_{max}$ values were 7.2 mg/ml and 16.3 U/mg, respectively, for birchwood xylan as the substrate. Nucleotide sequence of the PCR-cloned gene was determined to have the open reading frame encoding a polypeptide of 212 amino acids. The N-terminal amino acid sequence and the nucleotide sequence analyses predicted that the precursor xylanase contained a signal peptide composed of 28 amino acids and a catalytically active 19.9-kDa peptide fragment. The deduced amino acid sequence shared extensive similarity with those of the glycoside hydrolase family 11 of xylanases from other bacteria. The predicted amino acid sequence contained two glutamate residues, previously identified as essential and conserved for active sites in other xylanases of the glycoside hydrolase family 11.

• 대한바이러스학회지
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• 제30권1호
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• pp.83-99
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• 2000

A defective HIV-1 helper virus DNA, pHyPC, was assembled by deleting the RNA packaging signal, env, nef and the 3'LTR sequences. HIV-1 like virus particles that carry the HIV-1 receptor, CD4 were generated by co expression of pHyPC and plasmid DNAs encoding different chimeric CD4 proteins. The CD4 particles, sharing the CD4 ectodomain, precisely fused to different membrane anchors. CD4(+) particles specifically bound to HIV-1 Env expressing cells, but any signs of infection into these cells were not detected. Binding was only partially blocked by either polyclonal anti-CD4 antibodies or by high concentrations of soluble CD4. Surprisingly, CD4(+) particles also adsorbed to HeLa, CHO, NIH3T3 and COS-7 cells in the absence of HIV-1 Env expression. Adsorption was comparable in strength and speed to the highly specific CD4-Env interaction. CD4(-) particles exhibited only background levels of binding. Cell binding was CD4. dependent, but it was independent of the cell type from which the CD4(+) particles originated. Interestingly, CD4-dependent/Env-independent binding was only found when CD4 was present on virus particles. This suggests that the micro-environment of CD4 on virus particles uniquely expose this new cell binding activity. Its high affinity could explain in part why infection of Env(+) cells by CD4(+) particles was not detected. Further experiments will be required to evaluate whether this strong membrane interaction could represent one step in the multiple-step viral entry process.

• Asian-Australasian Journal of Animal Sciences
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• 제28권7호
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• pp.1006-1013
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• 2015

Heat-stress remains a costly issue for animal production, especially for poultry as they lack sweat glands, and alleviating heat-stress is necessary for ensuring animal production in hot environment. A high ${\gamma}$-aminobutyric acid (GABA)-producer Lactobacillus strain was used to investigate the effect of dietary GABA-producer on laying performance and egg quality in heat-stressed Hy-line brown hens. Hy-Line brown hens (n = 1,164) at 280 days of age were randomly divided into 4 groups based on the amount of freeze-dried GABA-producer added to the basal diet as follows: i) 0 mg/kg, ii) 25 mg/kg, iii) 50 mg/kg, and iv) 100 mg/kg. All hens were subjected to heat-stress treatment through maintaining the temperature and the relative humidity at $28.83{\pm}3.85^{\circ}C$ and 37% to 53.9%, respectively. During the experiment, laying rate, egg weight and feed intake of hens were recorded daily. At the 30th and 60th day after the start of the experiment, biochemical parameters, enzyme activity and immune activity in serum were measured. Egg production, average egg weight, average daily feed intake, feed conversion ratio and percentage of speckled egg, soft shell egg and misshaped egg were significantly improved (p<0.05) by the increasing supplementation of the dietary GABA-producer. Shape index, eggshell thickness, strength and weight were increased linearly with increasing GABA-producer supplementation. The level of calcium, phosphorus, glucose, total protein and albumin in serum of the hens fed GABA-producing strain supplemented diet was significantly higher (p<0.05) than that of the hens fed the basal diet, whereas cholesterol level was decreased. Compared with the basal diet, GABA-producer strain supplementation increased serum level of glutathione peroxidase (p = 0.009) and superoxide dismutase. In conclusion, GABA-producer played an important role in alleviating heat-stress, the isolated GABA-producer strain might be a potential natural and safe probiotic to use to improve laying performance and egg quality in heat-stressed hens.

• Molecules and Cells
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• 제20권3호
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• pp.385-391
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• 2005

As a first step towards identifying genes involving in the signal transduction pathways mediating rice blast resistance, we isolated 3 mutants lines that showed enhanced susceptibility to rice blast KJ105 (91-033) from a T-DNA insertion library of the japonica rice cultivar, Hwayeong. Since none of the susceptible phenotypes co-segregated with the T-DNA insertion we adapted a map-based cloning strategy to isolate the gene(s) responsible for the enhanced susceptibility of the Hwayeong mutants. A genetic mapping population was produced by crossing the resistant wild type Hwayeong with the susceptible cultivar, Nagdong. Chi-square analysis of the $F_2$ segregating population indicated that resistance in Hwayeong was controlled by a single major gene that we tentatively named Pi-hy. Randomly selected susceptible plants in the $F_2$ population were used to build an initial map of Pi-hy. The SSLP marker RM2265 on chromosome 2 was closely linked to resistance. High resolution mapping using 105 $F_2$ plants revealed that the resistance gene was tightly linked, or identical, to Pib, a resistance gene with a nucleotide binding sequence and leucine-rich repeats (NB-LRR) previously isolated. Sequence analysis of the Pib locus amplified from three susceptible mutants revealed lesions within this gene, demonstrating that the Pi-hy gene is Pib. The Pib mutations in 1D-22-10-13, 1D-54-16-8, and 1C-143-16-1 were, respectively, a missense mutation in the conserved NB domain 3, a nonsense mutation in the 5th LRR, and a nonsense mutation in the C terminus following the LRRs that causes a small deletion of the C terminus. These findings provide evidence that NB domain 3 and the C terminus are required for full activity of the plant R gene. They also suggest that alterations of the resistance gene can cause major differences in pathogen specificity by affecting interactions with an avirulence factor.