• 한국축산식품학회지
• /
• 제25권2호
• /
• pp.238-243
• /
• 2005

산양유 $\beta-casein$의 효소에 의한 가수분해 특성과 가수분해물의 ACE 저해 효과를 측정하고자 산양유의 $\beta-casein$을 양이온 교환 컬럼인 Mono S HR 5/5를 이용하여 분리하였으며 분리된 $\beta-casein$을 동물성 분해효소인 trypsin으로 처리하여 가수분해 특성을 확인하였고 가수분해물의 ACE 저해활성을 측정하였다. Mono S HR 5/5 양이온 교환 컬럼을 이용한 산양유 산 케이신으로 부터 순수한 $\beta-casein$의 분리는 SDS-PAGE를 이용하여 확인한 결과 순수한 $\beta-casein$의 분리가 이루어졌음을 확인할 수 있었다. $\beta-casein$을 $37^{\circ}C4$에서 trypsin으로 처리하여 전기영동으로 확인한 결과 가수분해 직후부터 $\beta-casein$ 위치의 band가 희미해지기 시작하고 저분자량의 band가 나타나기 시작하였으나 120분이 지난 후에는 모든 band가 가수분해되어 사라졌고 산양유에서 분리된 $\beta-casein$을 trypsin으로 처리하여 120분 경과 후 그 가수분해물을 이용하여 ACE 저해효과를 측정한 결과 가수분해하지 않은 $\beta-casein$은 $1.80\pm1.21\%$의 ACE 저해활성을 보였으나 trypsin으로 가수분해하여 ACE 저해 활성을 측정하였을 때 $25.36\pm0.79\%$의 저해 활성을 나타내었으며, trypsin에 의한 $\beta-casein$가수분해물의 $IC_{50}$을 측정한 결과 $308.7\pm2.77({\mu}g/mL)$로 나타났다.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제8권6호
• /
• pp.349-353
• /
• 2003

The physiological characteristics of cultures of very high cell mass (e.g. 10g cell mass/L), termed“ultrahigh cell density cultures”is reviewed. A close relationship was found between the length of the optical path (OP) in flat-plate reactors and the optimal cell density of the culture as well as its areal (g m$\^$-2/ day$\^$-1/) productivity. Cell-growth inhibition (GI) unfolds as culture density surpasses a certain threshold. If it is constantly relieved, a 1.0cm OP reactor could produce ca. 50% more than reactors with longer OP, e.g. 5 or 10cm. This unique effect, discovered by Hu et al. [3], is explained in terms of the relationships between the frequency of the light-dark cycle (L-D cycle), cells undergo in their travel between the light and dark volumes in the reactor, and the turnover time of the photosynthetic center (PC). In long OP reactors (5cm and above) the L-D cycle time may be orders of magnitude longer than the PC turnover time, resulting in a light regime in which the cells are exposed along the L-D cycle, to long, wasteful dark periods. In contrast, in reactors with an OP of ca. 1.0 cm, the L-D cycle frequency approaches the PC turnover time resulting in a significant reduction of the wasteful dark exposure time, thereby inducing a surge in photosynthetic efficiency. Presently, the major difficulty in mass cultivation of ultrahigh-density culture (UHDC) concerns cell growth inhibition in the culture, the exact nature of which is awaiting detailed investigation.

• 한국식물병리학회지
• /
• 제11권3호
• /
• pp.245-251
• /
• 1995

Nine hundred and ninety-two isolates of Botrytis cinerea were obtained from infected strawberries, tomatoes and cucumbers in Taejon, Gongju, Puyo, Nonsan and Kimhae in Korea. Six hundred forty-two (64.7%) isolates were benomyl resistant (BR), 245 (24.7%) were procymidone resistant (PR), and 105 (10.6%) were dichlofluanid resistant (DR). In the minimum inhibitory concentration (MIC) test, DR isolates showed mycelial growth on the PDA incorporated with 100 or 500 $\mu\textrm{g}$/ml of dichlofluanid, while dichlofluanid sensitive (DS) isolates did not grow on the PDA incorporated even with 10 $\mu\textrm{g}$/ml of dichlofluanid. Chemical concentrations for inhibition of spore germination were much lower than those for inhibition of mycelial growth. IC50 values, the effective concentrations for 50% inhibition of spore germination, for DR were 0.11~0.29 $\mu\textrm{g}$/ml, whereas they were 0.04~0.09 $\mu\textrm{g}$/ml for DS isolates. In comparison of fitness-related characteristics such as virulence, sclerotial formation, and sporulation, DR isolates were inferior to DS isolates. However, mycelial growth was little different between DR isolates and DS isolates.

• 한국미생물·생명공학회지
• /
• 제22권1호
• /
• pp.7-12
• /
• 1994

One bacterial strain, that had made the largest inhibition zone at the antagonism assay and also that lost the inhibition activity by the protease treatment, was isolated from raw milk. That strain was identified as Streptococcus salivarius subsp. thermophilus. The specific growht rate of this strain was maximum at 45$\circ $C. However, at this temperature the strain produced no bacteriocin. The bacteriocin activity was quite stable even at high temperature. Moreover, the activity of the vacteriocin was sensitive to proteases. but not to $\alpha $-amylase, DNase I, or RNase.

• Preventive Nutrition and Food Science
• /
• 제8권2호
• /
• pp.141-144
• /
• 2003

Ixeris dentata Nakai (Compositae) is a perennial herb which has been used as a folk medicine for treating diabetes and gastroenteric troubles in Korea. Active compounds were isolated from the aerial parts of Ixeris dentata through the bioassay-guided fractionation and isolation method evaluated for inhibition of monoamine oxidase (MAO) in vitro. The compounds were identified as 5,7,3',4'-tetrahydroxyflavone (1) and 5,7,3',4'- tetrahydroxyflavone 7-glucoside (2), based on physical and spectroscopic characteristics. Compounds 1 and 2 showed a selective inhibition of type B MAO (MAO-B) activity, with IC/sub 50/ values of 15.3 μM and 36.4 μM, respectively, but did not inhibit type A MAO (MAO-A) activity.

• Corrosion Science and Technology
• /
• 제22권1호
• /
• pp.10-20
• /
• 2023

Because of its inexpensive cost, mild steel is frequently employed as a construction material in different industries. Unfortunately, because of its limited resistance to corrosion, a protective layer must be applied to keep it from decaying in acidic or basic environments. The presence of heteroatoms, such as nitrogen, oxygen, and pi-electrons in the Schiff base could cause effective adsorption on the mild steel surface, preventing corrosion. The weight loss method and scanning electron microscopy (SEM) were used to investigate the inhibitory effects of APIDO on mild steel in a 1 M hydrochloric acid environment. The efficiency of inhibition increased as the inhibitor concentration increased and decreased as the temperature increased. The SEM analysis confirmed that the corrosion inhibition of APIDO proceeded by the formation of an organic protective layer over the mild steel surface by the adsorption process. Simulations based on the density functional theory are used to associate inhibitory efficacy with basic molecular characteristics. The findings acquired were compatible with the experimental information provided in the research.

• Transactions on Electrical and Electronic Materials
• /
• 제8권1호
• /
• pp.5-10
• /
• 2007

Using a reference slurry, ammonium dodecyl sulfate (ADS), an anionic and environmentally friendly surfactant, was investigated as an alternative to BTA for its inhibition and lubrication characteristics. Results demonstrated that the inhibition efficiency of ADS was superior to that of BTA. Coefficient of friction (COF) was the lowest when the slurry contained ADS. This suggested that adsorbed ADS on the surface provided lubricating action thereby reducing the wear between the contacting surfaces. Temperature results were consistent with the COF and removal rate data. ADS showed the lowest temperature rise again confirming the softening effect of the adsorbed surfactant layer and less energy dissipation due to friction. Spectral analysis of shear force showed that increasing the pad-wafer sliding velocity at constant wafer pressure shifted the high frequency spectral peaks to lower frequencies while increasing the variance of the frictional force. Addition of ADS reduced the fluctuating component of the shear force and the extent of the pre-existing stick-slip phenomena caused by the kinematics of the process and collision event between pad asperities with the wafer. By contrast, in the case of BTA, there were no such observed benefits but instead undesirable effects were seen at some polishing conditions. This work underscored the importance of real-time force spectroscopy in elucidating the adsorption, lubrication and inhibition of additives in slurries in CMP.

• 대한토목학회논문집
• /
• 제7권2호
• /
• pp.37-44
• /
• 1987

활성탄을 이용하여 chloroform, 4 염화탄소 및 crystal violet의 흡착특성(吸着特性)을 단일용질계(單一溶質系)와 2 용질계(溶質系)에서 연구(硏究)하였다. 단일용질계(單一溶質系)에서 각 용질(溶質)의 흡착(吸着)은 Freundlich 식(式)에 의해 적절히 표현되었다. 2 용질계(溶質系)에서의 흡착(吸着)의 농도(濃度)가 1 mg/l 이하의 낮은 농도(濃度)에서도 심한 조해현상(阻害現狀)을 나타냈다. chloroform의 흡착시(吸着時) 화학구조가 유사(類似)한 4 염화탄소가 화학구조가 상이(相異)한 crystal violet 에 비해 훨씬 큰 영향을 미쳤다. 조해효과(阻害效果)는 crystal violet 흡착시(吸着時) chloroform 에 의한 것이 가장 높았으며 chloroform 과 4 염화탄소가 서로 미치는 영향은 대등하였다. 2 용질계(溶質系)는 Fritz 와 Schl${\ddot{u}}$nder 모형(模型)에 의해 적절히 표현(表現)할 수 있었고 훨씬 간단한 3 상수(常數) Freundlich 식(式)에 의해 표현가능(表現可能)하였다.

• KSBB Journal
• /
• 제14권2호
• /
• pp.136-140
• /
• 1999

Characteristics of organic acid degradation by isolated yeast strain was investigated. Optimum initial pH was 5. Increase in cell mass was proportional to the decrease in organic acid degradation. Also no accumulation of byproduct was observed during degradation. Acetic acid degraded fast, followed by butyric acid and propionic acid in order. No significant substrate inhibition was observed up to 12 g/L of acetic acid 7 g/L of propionic acid, respectively. However, inhibition of butyric acid was significant above 4 g/L. Cell mass yield was 0.2-0.4 g cell/g acids and decreased at high decreased at high organic acid concentration. 95% of organic acid (7.5 g/L), corresponding to 13,000 ppm, was degraded in 30-40 hours.

• 한국약용작물학회지
• /
• 제20권5호
• /
• pp.315-319
• /
• 2012

This study was conducted to select plant growth regulators effective at ginseng berry set inhibition to help root growth in Korean ginseng (Panax ginseng C. A. Meyer). PGRs (ethephon, gibberellic acid, maleic hydrazide, coumarin) were applied to field grown 5-year-old Korean ginseng between one and two times, before and during bloom in 2009, 2010. The number of treatment was more effective in ginseng berry set inhibition when used two times compared with one time in GA 1,000 ppm, MH (5,000, 10,000 ppm), coumarin (5,000, 10,000 ppm) treatment. According to treatment period of plant growth regulator, ginseng berry set inhibition rate from 20days before flowering date to 5days after blooming was the highest in MH 5000 ppm showing 99.9% and the lowest in GA 100 ppm showing 32.8%. The spray treatments of Ethephon (50, 150 ppm) and MH (5,000, 10,000 ppm) from 20 days before the flowering bloom up to 5 days before, and coumarin (5,000, 10,000 ppm) from 20 days to 6 days and before blooming that induced the inhibitory effect more than 90% after 12 weeks. Considering ginseng berry set inhibition characteristics and treatment period ethephon and coumarin was important about applied period but, MH treatment appeared to effective ginseng berry set inhibition regardless of treatment period.