• 한국수소및신에너지학회논문집
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• 제16권1호
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• pp.17-24
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• 2005

We experimented on growth in light and production of hydrogen and organic matters in dark fermentation by using C. reinhardtii. In the light, growth rate of C. reinhardtii following $CO_2$ fixation was proportional to consumption rate of nitrogen source. And the starch in cell was accumulated more when the period of culture was lengthened more. But the accumulation rate of starch in cell was decreased when the growth rate of cell become dull. In the dark fermentation, the production volume and production rate of hydrogen were the highest value in the mid exponential state among other states. The utilization efficiency of substrate was better in the early exponential state than other states. In production of organic matters, acetic acid didn't change remarkably and ethanol showed the highest value in early exponential state.

• Journal of Microbiology
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• 제34권2호
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• pp.172-178
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• 1996

Methylobacillus sp. strain SK1, which grows only on methanol, was found to grow in the absence of added copper. The doubling time (t$_{d}$ = 1.3 h) of the bacterium growing at the exponential growth phase at 30.deg.C in the absence of copper was the same as that of the cell growing in the presence of copper. The bacterium growing after the exponential phase in the absence of copper, however, grew faster than the cell growing in the presence of copper. Cells harvested after thee arly stationary phase in the presence of copper were found to exhibit no methanol dehydrogenase (MDH) activity, but the amount and subunit structure of the enzyme in the cells were almost the same as that in cells harboring active MDH. Pellets of the cells harvested after the early stationary phase in the presence of copper were pale green. Cell-free extracts prepared from cells harvested at the early stationary phase in the presence of copper were pink and exhibited MDH activity, but it turned dark-green rapidly from the surface under air. The green-colored portions of the extracts showed no MDH activity and contained c-type cytochromes that were oxidized completely. The inactive MDH activity and contained c-type cytochromes that were oxidized completely. The inactive MDH proteins in the green portions were found to have antigenic sites identical to those of the active one as the inactive MDHs in cells grown in the presence of copper. The bacterium was found to accumulate copper actively during the exponential growth phase. MDH prepared from cells grown in the presence or absence of copper was found to be more stable under nitrogen gas than under air. Methanol at 10 mM was found to enhance the stability of the MDH under air.r.

• KSBB Journal
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• 제15권5호
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• pp.428-433
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• 2000

희수 (Camptotheca acuminata) 현닥세포배양에서 최근 항암 제로서 관심을 팔고있는 camptothecin을 얻기 위하여 연구를 수행하였다. 현탁세포배양에서 exponential phase의 최고 생장 속도는 $0.269day^{-1}$이었으며 배가시간이 2.58일이었다. Camptothecin 은 배양초기에 생성되지 않고 exponential phase 말기부터 서서히 생성되어 stationary phase 초기에 최고를 나타내고 이후 급격히 감소하였다. Camptothecin의 생산을 촉진하기 위하여 elicitor를 사F용하였다. 여러 elicitor 중 jasmonic acid와 cellulase 가 camptothecin의 생성을 증가시켰다, Elicitor는 접종과 동시 에 투여 했을 때 가장 효과가 좋았으며, jasmonic acid와 cellulase 의 combination으로 효과가 더욱 증진했는데 대조구에 비하여 약 20배 정도 증가한 $20.42{\times}10^{-3}mg/\ell$ 의 camptothecin이 생 성되었다. 이것은 생산량을 증가시킨 것뿐만 아니라 생산기 간도 약 1/4로 단축시키는 결과를 얻을 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제22권11호
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• pp.1518-1522
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• 2012

Leuconostoc mesenteroides is a heterofermentative Grampositive bacterium that plays key roles in fermentation of foods such as kimchi, sauerkraut, and milk, leading to the production of various organic acids and aromatic compounds. To study the microbiological and genomic characteristics of L. mesenteroides, we have developed a new chemically defined minimal medium by using the single omission technique. During the exponential cell growth, this species required glutamine, methionine, valine, and nicotinic acid as essential nutrients and 8 amino acids (arginine, cysteine, histidine, leucine, phenylalanine, proline, threonine, and tryptophan), 5 vitamins (ascorbic acid, folic acid, inosine, calcium panthothenate, and thiamine), and others (manganese, magnesium, adenine, uracil, and Tween 80) as supplemental nutrients. This medium is useful to study the metabolic characteristics of L. mesenteroides and to explain its role in food fermentation.

• 한국토양비료학회지
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• 제46권4호
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• pp.245-252
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• 2013

Leaf area index (LAI) is important in explaining the ability of crops to intercept solar energy for biomass production, amount of plant transpiration, and in understanding the impact of crop management practices on crop growth. This paper describes a procedure for estimating LAI as a function of image-derived vegetation indices from temporal series of RapidEye imagery obtained from 2010 to 2012 using empirical models in a rice plain in Seosan, Chungcheongnam-do. Rice plants were sampled every two weeks to investigate LAI, fresh and dry biomass from late May to early October. RapidEye images were taken from June to September every year and corrected geometrically and atmospherically to calculate normalized difference vegetation index (NDVI). Linear, exponential, and expolinear models were developed to relate temporal satellite NDVIs to measured LAI. The expolinear model provided more accurate results to predict LAI than linear or exponential models based on root mean square error. The LAI distribution was in strong agreement with the field measurements in terms of geographical variation and relative numerical values when RapidEye imagery was applied to expolinear model. The spatial trend of LAI corresponded with the variation in the vegetation growth condition.

• Biotechnology and Bioprocess Engineering:BBE
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• 제3권1호
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• pp.11-14
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• 1998

A toluene-oxidizing strain of Pseudomanas mendocina KR1 containing toluene-4-mono-oxygenase (TMO) completely degrades TCE with the addition of toluene as a co-substrate in aerobic condition. In order to construct in situ bioremediation system for TCE degradation without any growth-stimulating nutrients or toxic inducer such as toluene, we used the carbon-starvation promoter of Pseudomonas putida MK1 (Kim, Y. et al., J. bacteriol., 1995). Upon entry into the stationary phase due to the deprivation of nutrients, this promoter is strongly induced without further cell growth. The TMO gene cluster (4.5 kb) was spliced downstream of the carbon starvation promoter of Pseudomonas putida MK1, already cloned in pUC19. TMO under the carbon starvation promoter was not expressed in E. coli cells either in stationary phase or exponential phase. For TMO expression in Pseudomonas strains, tmo and carbon starvation promoter region were recloned into a modified broad-host range vector pMMB67HES which was made from pMMB67HE(8.9 kb) by deletion of tac promoter and lacIq (about 1.5 kb). Indigo was produced by TMO under the carbon starvation promoter in a Pseudomonas strain of post-exponential phase on M9 (0.2% glucose and 1mM indole) or LB. 18% of TCE was degraded in 14 hours after entering the stationary phase at the initial concentration of 6.6 ${\mu}$M in liquid phase.

• 대한수학회보
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• 제61권1호
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• pp.161-193
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• 2024

In this paper, we consider the asymptotic behavior of solutions for the partly dissipative reaction diffusion systems of the FitzHugh-Nagumo type with hereditary memory and a very large class of nonlinearities, which have no restriction on the upper growth of the nonlinearity. We first prove the existence and uniqueness of weak solutions to the initial boundary value problem for the above-mentioned model. Next, we investigate the existence of a uniform attractor of this problem, where the time-dependent forcing term h ∈ L²_b(ℝ; H^-1(ℝ^N)) is the only translation bounded instead of translation compact. Finally, we prove the regularity of the uniform attractor A, i.e., A is a bounded subset of H²(ℝ^N) × H¹(ℝ^N) × L²_µ(ℝ⁺, H²(ℝ^N)). The results in this paper will extend and improve some previously obtained results, which have not been studied before in the case of non-autonomous, exponential growth nonlinearity and contain memory kernels.

• Applied Biological Chemistry
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• 제43권4호
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• pp.231-235
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• 2000

담배 배양 세포의 성장과정 중의 칼모듈린 농도변화 및 칼모듈린 결합 단백질의 종류에 대하여 조사하고 이들 단백질들 중 글루탐산 탈탄산효소를 immunodetection과 활성측정으로 확인하였다. 담배세포는 유도기(초기 $1{\sim}2$일간), 대수증식기($3{\sim}5$일), 정지기 등의 전형적인 성장 패턴을 보였다. 칼모듈린의 농도는 비록 대수증식기에 약간 감소하는 경향을 보이다 정지기에 이르면서 유도기의 수준을 회복하는 것으로 나타났지만 전체적으로는 성장단계에 관계없이 유사한 수준을 유지하는 것으로 나타났다. 주요 칼슘-의존형 칼모듈린 결합단백질은 56, 46, 36, 32-kDa의 4종류인 것으로 조사되었고, 모노클로날 항체를 이용하여 immunodetection을 실시해 본 결과 56-kDa 단백질이 담배 글루탐산 탈탄산효소로 확인되었다. 56-kDa의 글루탐산 탈탄산효소는 대수증식기에 수확한 세포에서 가장 많이 검출되었고, 이와같은 패턴은 효소활성 측정에서도 확인되었다. 이러한 결과들은 담배세포의 성장과정 중에 칼슘/칼모듈린-의존형 글루탐산 탈탄산효소 농도가 조절되고 있음을 제안해 주는 것이다.

• BMB Reports
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• 제29권3호
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• pp.221-224
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• 1996

To examine the growth-phase dependent control of Escherichia coli rnpB gene we used a combination of Northern analysis for RNA determination and Southern analysis for plasmid DNA determination. The relative amounts of metabolically unstable transcript derived from the internally deleted rnpB gene harbored on a multicopy plasmid as well as the relative plasmid contents were measured by Northern analysis and Southern analysis, respectively, of total nucleic acids from E coli cells containing the plasmid. The relative transcription activity of the rnB was represented by a ratio of the relative amount of the transcript to that of the plasmid DNA during bacterial growth. The rnpB transcription increased rapidly with time during exponential growth, but started to decrease before the transition period of an exponential growing cell culture into the stationary phase. Although the expression pattern was similar to the changes of ${\beta}-galactosidase$ activity expressed from the lysogenic strain carrying the chromosomal rnpB-lacZ fusion which were shown in a previous work, the present data appears to represent a more actual growth-phase control of the rnpB transcription than the previous data by the ${\beta}-galactosidase$ assay. In addition the present method described for a direct analysis of both RNA and plasmid DNA provides a rapid and efficient method that can applied to an examination of transcription control by using a multicopy plasmid.

• 한국미생물·생명공학회지
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• 제13권3호
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• pp.239-243
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• 1985

Ethanol, Acetic acid 및 Acetaldehyde를 단일 탄소원으로 하여 Candida sP. JY-5 효모의 증식특성을 batch culture를 통해 검토하였다. Ethanol상에서 이 효모의 지수적 증식기 동안의 비증식도 ($\mu$) 값은 농도가 0.5g/l 이상일 경우 그 초기 농도에 따라 변화하나 비례하지는 않았다. 최대 비증식도는 0.291$hr^{-1}$이었고 최대 증식수율은 10g/l 농도에서 61.2 %이었다. Acetic acid상에서의 비증식도는 이 기질의 초기 농도에 관계없이 일정하였으며 그 값이 0.106$hr^{-1}$. 최대 증식수율은 10g/l 농도에서 46.8%로 나타났다. 한편 Acetaldehyde 기질에서 지수적 증식기 동안의 최대 비증식도는 0. 063$hr^{-1}$이었고 최대 증식수율은 0.2g/l 농도에서 44.9%였다.