• 한국양식학회지
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• 제6권3호
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• pp.173-186
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• 1993

대하의 단백질요구량과 배합 사료에 어분 대신 대두백으로 대체하고 여기에 오징어유를 첨가한 먹이에 대한 성장 결과는 다음과 같다. 배합 사료를 먹이로 공급할 때 단백질 함량을 $25\~50\%$로 실험한 결과, 단백질 함량 $40\%$에서 가장 높은 생존율과 빠른 성장을 보였고, 단백질 함량 25, 30, 35, 40, 45, $50\%$인 배합사료를 대하에 공급하였을때 생존율은 각각 74.0, 82.0, 91.0, 97.0, 93.0, $88.0\%$이었다. 최적의 사료내 단백질 함량은 $13\~84mg$인 대하 치하는 $40.4\%$, $0.9\~8.1g$ 인 대하는 $39.9\%$로 계산되었다. 사료중 단백질원을 어분 대신 대두백으로 대체할 때에는 대두박 함량을 $0.0\~76.0\%$로 실험한 결과, 대두백 함량이 많아질수록 생존율과 성장이 둔화되는 경향을 보였지만, 오징어유를 대두박 함량의 $2.5\%$ 첨가하였을때 생존율은 향상되었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권6호
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• pp.523-527
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• 2004

Recombinant Saccharomyces cerevisiae expression systems were developed to pro­duce a novel human anti-angiogenic protein called LK8, an 86 amino-acid kringle fragment pro­tein with three disulfide linkages. Galactose-inducible LK8 expression plasmid was constructed, and LK8 production levels by four S. cerevisiae strains were compared in order to select an op­timal host strain. S. cerevisiae 2805 was the most efficient among the strains tested. Elevating the LK8 gene copy number through multiple integration using 8-sequences as target sites re­sulted in more than a two-fold increase in the LK8 production level compared with the plasmid­based expression system. The maximum LK8 protein concentration of 25 mg/L was obtained from batch cultivation of the yeast transformant that harbors 16 copies of the LK8 gene. In con­clusion, the strain integrated with the multiple LK8 gene secreted the protein with relatively high yield, although, the increased LK8 gene dosage over 11 copies did not lead to further en­hancement in batch cultivations.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권6호
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• pp.418-421
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• 2000

A new direct colorimetric assay of microcystin in water and algal samples is proposed consisting of two procedures as follows: 1) the elimination of phosphorus in the sample and concentration of microcystin using a C(sub)18 cartridge, 2) the detection of the released phosphorus by the ascorbic acid method and determination of protein phosphatase (PP) inhibition by microcystin. The optimum amounts of phosphorylase ${\alpha}$ and PP-1 in 50 ${\mu}$L concentrated sample were 50$\mu\textrm{g}$/50${\mu}$L buffer and 1.0unit/50${\mu}$L buffer, respectively, for the best assay. The pH for the maximum activity of PP-1 was 8. The minimum detectable concentration for this method was about 0.02$\mu\textrm{g}$/L, which is sufficient to meet the proposed guideline level of 1$\mu\textrm{g}$ microcystin/L in drinking water. Consequently, it would seem that the proposed direct colorimetric assay using PP is a rapid, easy, and convenient method for the detection of microcystin in water and algal samples.

• 한국포장학회지
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• 제15권3호
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• pp.99-104
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• 2009

Soy protein isolate (SPI)-based nanocomposite films with three different types of nanoclays, such as Cloisite $Na^+$, Cloisite 20A, and Cloisite 30B, were prepared using a solution casting method, and their optical, tensile, and water vapor barrier properties were determined to investigate the effect of nano-clay type on film properties. Among the tested nanoclays, Cloisite $Na^+$, a hydrophilic montmorillonite (MMT), exhibited the highest transparency with least opaqueness, the highest tensile strength, and the highest water vapor barrier properties, indicating Cloisite $Na^+$ is the most compatible with SPI polymer matrix to form nanocomposite films. The film properties of SPI/Cloisite $Na^+$ nanocomposite films were strongly dependent on the concentration of the clay. Film properties such as optical, tensile, and water vapor barrier properties improved significantly (p<0.05) as the concentration of clay increased. However, the effectiveness of addition of the clay reduced above a certain level (i.e., 5wt%), indicating that there is an optimum amount of clay addition to exploit the full advantage of nanocmposite films.

• BMB Reports
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• 제31권2호
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• pp.130-134
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• 1998

An aldolase gene has been cloned from Methanococcus jannaschii. The coding region of the gene has been expressed in E. coli using a pET system to a level of 30% of total cellular proteins. The protein was purified to more than 95 % homogeneity by heat treatment and ion exchange chromatography. The protein performed an aldol condensation reaction with glyceraldehyde as substrate and dihydroxyacetone phosphate as a carboxyl donor. The protein was determined to be a type II aldolase which requires the $Zn^{2+}$ ion as a metal cofactor. This enzyme has a broad range of optimum pH (7-9) and temperature ($50-80^{\circ}C$). It shows strong stability against heat, chemical denaturants, as well as a high percentage' of organic solvents. The half-life of this enzyme at $85^{\circ}C$ is more than 24 h and it maintains more than 90% of aldolase activity in the presence of 6 M urea, 50% acetonitrile, or 15% isopropyl alcohol.

• 한국조리학회지
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• 제23권5호
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• pp.101-108
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• 2017

This study was conducted to investigate the noodle added with Pachyrhizus erosus powder. Total contents of carbohydrates, crude protein, crude lipid, ash, and total dietary fiber were 87.14%, 3.14%, 0.81%, 7.82%, and 49.12%, respectively. The water-binding capacity was significantly increased by increasing amount of the Pachyrhizus erosus powder. When the volume of the noodles was measured after cooking, there was no difference between the control and Pachyrhizus erosus powder groups. The texture characteristics of hardness increased by increasing amount of the Pachyrhizus erosus powder. As a result of the sensory test, the 1.5% Pachyrhizus erosus powder noodles showed the highest scores for all items including appearance, flavor, taste, texture and overall acceptability. The bacterial counts of noodle decreased with greater Pachyrhizus erosus powder content on the third days. It is considered that research on antimicrobial activity should proceed in the future. As a result, it was finally suggested that optimum level of the Pachyrhizus erosus powder in the product was 1.5% level.

• 한국초지조사료학회지
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• 제16권3호
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• pp.225-229
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• 1996

To find out the optimum mixing level of wheat bran to improve the quality of 1st cut Alfalfa silage, this trial was canied out at two-year's Alfalfa monoculture field of the National Livestock Research Institute, Suwon, Korea, from May 1955 to Oct. 1995. The results are as follows. I. According to the increase of wheat bran mixing level, DM content was high from 23.19%(nil) to 35.70%(40% mixing), pH of silage were low from 5.51(nil) to 4.45(40% mixing). but there were not significant at 20% mixing or more(P>0.05). 2. Also it was appeared to the same trend at Lactic acid content and in the Flieg's score of silage it was highest as 59 in the 20% mixing level. 3. In chemical component of silages there were not significant at 20% mixing or more in crude protein, crude fiber and ashes content, 30% mixing or more in ether extract and 10% or less in NFE content(P>0.05). 4. TDN, NEL and StE contents were low as adding level was increased. respectively, but there were not significant(P>O.OS). As mentioned above the results, desirable mixing level of wheat bran to lstcut Alfalfa to improve the quality of silage was 20% of fresh weight.

• Asian-Australasian Journal of Animal Sciences
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• 제26권4호
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• pp.564-572
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• 2013

Two trials were conducted to investigate the effect of decreasing the crude protein (CP) content of diets for finishing pigs containing two levels of available lysine on nutrient digestibility, nitrogen (N) balance and production performance. Ten finishing diets containing five levels of CP (on average 144, 155, 168, 182 and 193 g/kg fresh basis) and two levels of available lysine (6.9 and 8.2 g/kg fresh basis) were formulated. The diets were offered to pigs on a performance trial (n = 800 Large White (LW)${\times}$Landrace (LR) pigs) from 10 wk of age until finish at 21 wks+5 d of age. Average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated. In addition, a digestibility/N balance trial was conducted using pigs (n = 80 $LW{\times}LR$) housed in metabolism crates. Digestibility of dry matter (DM), CP, oil, fibre and energy was determined. N balance values were determined through analysis of N content of urine and faeces ('as determined'). N balance values were also calculated using ADG values and assuming that 16% of growth is protein deposition ("as calculated"). Pig performance was poor between 10 and 13 wk of age which indicated that the dietary treatments were nutritionally inadequate for pigs less than 40 kg. There was a significant (p<0.01) quadratic effect of increasing CP level on feed intake, ADG and FCR from 10 to 13 wk which indicated that the lower CP levels did not supply adequate levels of essential or non-essential amino acids. There was no effect of increasing available lysine level throughout the early period, which in conjunction with the response in older pigs, suggested that both 8.2 and 6.9 g/kg available lysine were insufficient to drive optimum growth. There was a positive response (p<0.05) to increasing available lysine level from 13 wk to finish which indicated that 6.9 g/kg available lysine was not adequate for finishing pigs. Energy digestibility decreased with decreasing CP level of diets containing 6.9 g/kg available lysine which may be attributed to the higher fibre content of the lower CP diets. Nitrogen excretion (g/d) was lowered when dietary CP was reduced regardless of whether the values were determined through balance or calculated using ADG. Calculated N excretion decreased linearly (p<0.001) and quadratically (p<0.001) with decreasing dietary CP content. When the N balance figures calculated in this study were compared with those quoted in the Northern Ireland and English Nitrates Directive Action Programmes, N excretion was less per pig (wean to finish) offered a 169 g/kg CP, 8.2 g/kg available lysine diet (2.39 kg vs 3.41 kg (Northern Ireland) and 2.93 kg (England)).

• Asian-Australasian Journal of Animal Sciences
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• 제12권7호
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• pp.1096-1103
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• 1999

A study was conducted to clarify the impact of recombinant porcine somatotropin (pST) on the efficiency of absorbed nitrogen use for protein deposition in growing pigs. Three levels of dietary crude protein (9.0, 11.5, 14.0% CP) were used. Each had either a sub-optimum or near optimum lysine: CP concentration (Low-lysine, 3.8 g/100 g CP and High-lysine, 5.5 g/100g CP) in order to achieve different metabolic efficiencies for nitrogen deposition (ca. 45 vs. 60%). Twelve crossbred female pigs $(59{\pm}4kg\;BW)$ were placed in metabolism cages and fitted with bladder catheters. Each pig received an excipient injection daily for the first 10-d, a pST (5 mg/d) injection for the second 10-d, and then excipient for the last 10-d. Pigs were randomly assigned to one of six dietary treatments (2 pigs/diet) and fed 4 times per d at $92g/kg\;BW^{0.75}$ $(3{\times}maintenance)$. Means for the excipient period were compared to means for the pST period. Urinary nitrogen (N) output declined in pST-treated pigs (p<0.01) irrespective of dietary protein content or lysine level. Nitrogen retention increased by an average of 11% (p<0.01) with pST treatment (726 vs. $803mg\;N/kg^{0.75}\;BW/d$). Forty-eight percent of the absorbed N was retained with Low-lysine diets, but this increased to 53% with pST injection (+11%, p<0.01). Pigs fed High-lysine diets retained 62% of absorbed N which increased to 69% with pST (+11% p<0.01). the addition of lysine improved N use by 27% (High vs. Low, p<0.01), but the effect of lysine and pST was additive (+40%). Therefore, pST improves N retention and the efficiency of apparently absorbed N use in growing pigs (>60kg). It does so with diets having the potential for either low or high efficiencies of N use (48% and 62%). More work is needed to determine if the partial efficiency of N use improves in direct proportion to pST dose since the improvement in protein deposition is a function of pST dose.

• KSBB Journal
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• 제14권4호
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• pp.476-481
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• 1999

본 연구에서 갈락토즈를 거의 사용하지 않고 glucose repression 정도가 줄어든 변이주를 이용하여 발현최적화를 수행하였다. 두 균주에서의 GAL promoter에 의한 외래단백질 생산시 glucose repression 정도에 대해 조사하였는데 대조해 Y2805는 glucose가 다 소비된 후 2~3시간 지난 후 발현이 시작되나 변이주 Y334는 약 0.5g/L 글루코즈 농도에서 25%정도의 발현이 이루어짐에 따라 변이주 Y334는 GAL promoter에 미치는 glucose repression정도가 매우 약한 장점을 확인하였다. GAL promoter에 의한 외래 단백질 생산시 발현을 위한 최적 갈락토즈 농도를 조사하였는데, Y3805는 3% 까지의 높은 갈락토즈 농도에서, 변이주 Y334는 1%정도의 낮은 갈락토즈 농도에서 각각 최대 발현량을 보였으며 변이주 Y334는 특히 0.01%정도의 낮은 갈락토즈 농도에서도 최대 발현의 60%량을 발현하였고 오히려 높은 갈락토즈 농도에서는 성장장애 현상을 보였다. 두 균주를 이용하여 배지중 pH가 외래 단백질 생산에 미치는 영향을 조사하였는데 두 균주 모두 pH 5근처에서 최대 발현량을 보임을 알 수 있었다. GAL promoter에 의한 외래 단백질 생산시 글루코즈와 갈락토즈, 에탄올의 소비속도를 조사하였는데, 글루코즈와 에탄올의 소비속도는 거의 비슷하였으나 갈락토즈 소비속도는 Y2805는 0.1232 g/L/hr/O.D.이고, 변이주 Y334는 0.0131g/L/hr/O.D. 이다. 또한 두균주의 분비효율을 조사하였는데 Y2805는 발효후반부에 총 생산 albumin중 약 70%는 분비되었고 30%는 cell 내 위치하는 것을 알 수 있었고 Y334의 경우에는 발효후반부에 총 생산 albumin중 50%가 cell 밖으로 분비되고 50%는 cell 내에 존재하는 것으로 확인되었다. 이는 Y334의 해결해야 할 단점으로 생각 되어지며 이러한 문제의 해결을 위해 albumin 생산성이 2~3배 증가된 초분비 S. cerevisiae 돌연변이주 개발이 현재 진행중이다.