• Journal of Microbiology and Biotechnology
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• 제22권11호
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• pp.1486-1493
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• 2012

In this study, we investigated whether galactooligosaccharide (GOS) can be stably and steadily synthesized using immobilized ${\beta}$-galactosidase (${\beta}$-gal) inclusion body (IB)-containing E. coli cells during long-term repeated-batch operation. To improve the operational stability of this enzyme reactor system, immobilized E. coli cells were crosslinked with glutaraldehyde (GA) after immobilization of the E. coli. When we treated with 2% GA for E. coli crosslinking, GOS production continued to an elapsed time of 576 h, in which seven batch runs were operated consecutively. GOS production ranged from 51.6 to 78.5 g/l ($71.2{\pm}10.5$ g/l, n = 7) during those batch operations. In contrast, when we crosslinked E. coli with 4% GA, GOS production ranged from 31.5 to 64.0 g/l ($52.3{\pm}10.8$, n = 4), and only four consecutive batch runs were operated. Although we did not use an industrial ${\beta}$-gal for GOS production, in which a thermophile is used routinely, this represents the longest operation time for GOS production using E. coli ${\beta}$-gal. Improved stability and durability of the cell immobilization system were achieved using the crosslinking protocol. This strategy could be directly applied to other microbial enzyme reactor systems using cell immobilization to extend the operation time and/or improve the reactor system stability.

• Journal of Ecology and Environment
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• 제31권3호
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• pp.167-176
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• 2008

Atmospheric N deposition has far-reaching impacts on forest ecosystems, including on-site impacts such as soil acidification, fertilization, and nutrient imbalances, and off-site environmental impacts such as nitrate leaching and nitrous oxide emission. Although chronic N deposition has been believed to lead to forest N saturation, recent evidence suggests that N retention capacity, particularly in the forest floor, can be surprisingly high even under high N deposition. This review aims to provide an overview of N retention processes in the forest floor and the implications of changing C-N interactions for C sequestration. The fate of available N in forest soils has been explained by the competitive balance between tree roots, soil heterotrophs, and nitrifiers. However, high rates of N retention have been observed in numerous N addition experiments without noticeable increases in tree growth and soil respiration. Alternative hypotheses have been proposed to explain the gap between the input and loss of N in N-enriched, C-limited systems, including abiotic immobilization and mycorrhizal assimilation, both of which do not require additional C sources to incorporate N in soil N pools. Different fates of N in the forest floor have different implications for C sequestration. N-induced tree growth can enhance C accumulation in tree biomass as observed across temperate regions. C loss from forests can amount to or outweigh C gain in N-saturated, declining forests, while another type of 'C-N decoupling' can have positive or neutral effects on soil C sequestration through hampered organic matter decomposition or abiotic N immobilization, respectively.

• BMB Reports
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• 제28권2호
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• pp.155-161
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• 1995

A nicotinic acetylcholine receptor (nAchR) isolated from the electric tissues of Torpedo californica has been reconstituted into a vesicle comprising a bifunctional azo-ligand (Bae 1) compound, and a liposome containing phospholipids and cholesterol (1 : 1, w/w). The liposome-mediated reconstituted receptor showed a concentration-dependent response to cholinergic drugs in a lithium ion flux assay. This liposome-mediated reconstituted nAchR was immobilized onto an electrode using various synthetic polymers which were tested for their response to the cholinergic ligands. The immobilized nAchR not only exhibited a linear response to a wide range of cholinergic ligand concentrations but also retained an operational stability which lasted for longer than 6 days. Thus, this result provides a basis for application of the immobilized nAchR-based biosensor in detecting cholinergic ligands in vitro.

• The Korean Journal of Ecology
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• 제24권2호
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• pp.81-85
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• 2001

Decomposition of Zizania latifolia was investigated with litterbag method for 13 months from November in 1998 to December in 1999, at the fringe of stream at Boryeong, Chungnam Province in Korea. After 13 months, remaining mass of leaves, culms and rhizomes was 16.9, 14.7, and 10.1%, respectively. Mass loss of the rhizomes was higher than those of the leaves and culms. The decay rate of leaves, culms and rhizomes was 1.86, 2.00 and 2.36 per year, respectively. Initial concentration of N, P, K, Ca, and Mg of leaves, culms and rhizomes was 18.0, 14.5, 44.0 mg/g for N,0.18, 0.12, 0.67 mg/g for P, 14.1 ,14.2, 14.8 mg/g for K,3.6, 1.5, 0.3 mg/g for Ca, 1.1, 0.5, 0.5 mg/g for Mg, respectively. Concentrations of N and P in rhizomes were higher than those in leaves and culms. Except for Mg in rhizomes, there was no immobilization period during the decomposition. Most of the N, P and Mg were lost during the first 3 months. In case of K and Ca, most were lost within 1 month.

• 한국토양비료학회지
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• 제17권1호
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• pp.60-66
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• 1984

토양(土壤)이 상이(相異)한 조건(條件)에서 볏짚 및 퇴비시용시(堆肥施用時) 시비질소(施肥窒素)의 유기(有機) 및 무기화(無機化) 작용(作用)을 파악(把握)코저 중질소(重窒素) [$^{15}(NH_4)_2SO_4$]를 사용(使用)하여 실내시험(室內試驗)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 식질(埴質) 및 사질토양(砂質上壤)에 퇴비(堆肥) 및 볏짚시용시(施用時) 시비질소(施肥窒素)의 50~90%가 관수(灌水) 10일경(日頃) 유기화(有機化)되었다. 2. 시비질소(施肥窒素)의 유기화(有機化) 정도(程度)는 사질토양(砂質土壤)에 볏짚 시용시(施用時)가 타(他) 처리(處理)에 비(比)하여 보다 많은 유기화량(有機化量)을 보였다. 3. 유기화(有機化)된 시비질소(施肥窒素)는 담수(湛水) 300일(日) 이후(以後), 무기화(無機化) 되었으며 이 양(量)은 퇴비(堆肥)보다 볏짚시용시(施肥時), 그리고 사질(砂質)보다 식질토양(埴質土壤)에서 현저(顯著)히 많았다. 4. 시험후(試驗後) 토양(土壤)의 질소분별정양결과(窒素分別定量結果), 무기태질소(無機態窒素) ($NH_4{^-}N+NO_3{^-}N+NO_2{^-}N$)의 양(量)은 사질토양(砂質土壤)에서 많았다. 5. 사질토양(砂質土壤)에 볏짚시용시(施用時)와 식질토양(埴質土壞)에 퇴비시용시(堆肥施用時) 시험후(試驗後) 토양(土壤) 중(中) Aminoacid-N와 미동정유기태(未同定有機態) 질소(室素)의 함량(含量)이 증가(增加)되었으며 Aninoauger-N와 Humin-N의 함량(含量)은 처리간(處理間)에 일정(一定)하지 않았다.

• Journal of Microbiology
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• 제43권3호
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• pp.301-307
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• 2005

The feasibility of laccase production by immobilization of Pleurotus ostreatus 1804 on polyurethane foam (PUF) cubes with respect to media composition was studied in both batch and reactor systems. Enhanced laccase yield was evidenced due to immobilization. A relatively high maximum laccase activity of 312.6 U was observed with immobilized mycelia in shake flasks compared to the maximum laccase activity of free mycelia (272.2 U). It is evident from this study that the culture conditions studied, i.e. biomass level, pH, substrate concentration, yeast extract concentration, $Cu^{2+}$ concentration, and alcohol nature, showed significant influence on the laccase yield. Gel electrophoretic analysis showed the molecular weight of the laccase produced by immobilized P. ostreatus to be 66 kDa. The laccase yield was significantly higher and more rapid in the packed bed reactor than in the shake flask experiments. A maximum laccase yield of 392.9 U was observed within 144 h of the fermentation period with complete glucose depletion.

• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.70-74
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• 2003

The heterogeneous bioluminescence immunoassay for digoxin was developed using photoprotein, native aequorin as a label and the site-directed immobilization technique based on avidin/biotin interaction. Aequorin is a bioluminescence protein, originally isolated from the jellyfish Aequoria Victoria and an attractive label in analytical applications because of sensitive detection due to virtually no background bioluminescent signal. Digoxin is a cardioactive drug, and its therapeutic level in serum is at low concentration with very narrow therapeutic index. The aequorin-digoxigenin conjugates were synthesized by the N-hydroxysuccinimide ester method and characterized in terms of bioluminescent residual activity. The resulting dose-response curve shows that the detection limit is $1.0\;{\times}\;10^{-10}\;M$ and a dynamic range is three orders of magnitude, which was obtained by $1.0\;{times}\;10^{-10}\;M$ conjugate and 0.9 μg/mL anti-digoxin antibody. Three structurally similar molecules to digoxin were examined for their cross-reactivity. None of these three compounds showed any crossreactivity with digoxin antibody employed in this study. Standard amounts of digoxin corresponding to the therapeutic range were spiked into the each serum solution. Study of the serum matrix effect indicated that correlation coefficient shows good agreement between luminescence light intensity between in buffer and in serum.

• Journal of Korean Neurosurgical Society
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• 제55권1호
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• pp.1-4
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• 2014

Objective : The case fatality rate of nonlesional intracerebral hemorrhage (n-ICH) was high and not changed. Knowing the causes is important to their prevention; however, the reasons have not been studied. The aims of this study were to determine the cause of death, to improve the clinical outcomes. Methods : We retrospectively analyzed consecutive cases of nonlesional intracerebral hemorrhage in a prospective stroke registry from January 2010 to December 2010. Results : Among 174 patients ($61.83{\pm}13.36$, 28-90 years), 29 patients (16.7%) died during hospitalization. Most common cause of death was initial neurological damage (41.4%, 12/29). Seventeen patients who survived the initial damage may then develop various potentially fatal complications. Except for death due to the initial neurological sequelae, death associated with immobilization (such as pneumonia or thromboembolic complication) was the most common in eight cases (8/17, 47.1%). However, death due to early rebleeding was not common and occurred in only 2 cases (2/17, 11.8%). Age, initial Glasgow Coma Scale, and diabetes mellitus were statistically significant factors influencing mortality (p<0.05). Conclusion : Mortality of n-ICH is still high. Initial neurological damage is the most important factor; however, non-neurological medical complications are a large part of case fatality. Most cases of death of patients who survived from the first bleeding were due to complications of immobilization. These findings have implications for clinical practice and planning of clinical trials. In addition, future conduct of a randomized study will be necessary in order to evaluate the benefits of early mobilization for prevention of immobilization related complications.

• Applied Biological Chemistry
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• 제46권1호
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• pp.1-6
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• 2003

본 연구는 폐수 중의 질소 제거를 위한 생물학적 처리용 미생물 개발을 위한 목적으로 질소의 산화 능력이 뛰어난 균주를 분리하였다. 분리된 세균 중에서 질소 산화능과 생육 속도가 뛰어난 CH-N 균주를 선별하였으며, 생리, 생화학적 특성 조사에 의해 Bacillus sp로 추정되어 Bacillus sp. CH-N이라 명명하였다. 분리 균주는 0.5% glucose가 포함된 초기 pH가 7,0인 암모니아 및 아질산성 질소 함유 배지에서 30시간 배양 후 각각 85%와 90%의 암모니아성과 아질산성 질소의 감소율을 나타내었다. 폐수 및 생활하수에 분리 균주를 이용한 결과, 수질 속의 암모니아성 질소가 단시간에 크게 감소시키는 효과를 확인하였다. 균주를 고정시킨 담체의 질소산화 효과를 시험하고자 Bacillus sp. CH-N을 고정시킨 세라믹 담체를 이용한 결과, 배양 2일 후에는 암모니아성 질소가 전부 제거되었다.

• Nutrition Research and Practice
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• 제4권4호
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• pp.270-275
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• 2010

Catecholamines are among the first molecules that displayed a kind of response to prolonged or repeated stress. It is well established that long-term stress leads to the induction of catecholamine biosynthetic enzymes such as tyrosine hydroxylase (TH) and dopamine ${\beta}$-hydroxylase (DBH) in adrenal medulla. The aim of the present study was to evaluate the effects of ginseng on TH and DBH mRNA expression. Repeated (2 h daily, 14 days) immobilization stress resulted in a significant increase of TH and DBH mRNA levels in rat adrenal medulla. However, ginseng treatment reversed the stress-induced increase of TH and DBH mRNA expression in the immobilization-stressed rats. Nicotine as a ligand of the nicotinic acetylcholine receptor (nAChR) in adrenal medulla stimulates catecholamine secretion and activates TH and DBH gene expression. Nicotine treatment increased mRNA levels of TH and DBH by 3.3- and 3.1-fold in PC12 cells. The ginseng total saponin exhibited a significant reversal in the nicotine-induced increase of TH and DBH mRNA expression, decreasing the mRNA levels of TH and DBH by 57.2% and 48.9%, respectively in PC12 cells. In conclusion, immobilization stress induced catecholamine biosynthetic enzymes gene expression, while ginseng appeared to restore homeostasis via suppression of TH and DBH gene expression. In part, the regulatory activity in the TH and DBH gene expression of ginseng may account for the anti-stress action produced by ginseng.