• BMB Reports
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• 제46권5호
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• pp.244-251
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• 2013

Lignocellulosic materials are commonly used in bio-$H_2$ production for the sustainable energy resource development as they are abundant, cheap, renewable and highly biodegradable. In the process of the bio-$H_2$ production, the pretreated lignocellulosic materials are firstly converted to monosaccharides by enzymolysis and then to $H_2$ by fermentation. Since the structures of lignocellulosic materials are rather complex, the hydrolysates vary with the used materials. Even using the same lignocellulosic materials, the hydrolysates also change with different pretreatment methods. It has been shown that the appropriate hydrolysate compositions can dramatically improve the biological activities and bio-$H_2$ production performances. Over the past decades, hydrolysis with respect to different lignocellulosic materials and pretreatments has been widely investigated. Besides, effects of the hydrolysates on the biohydrogen yields have also been examined. In this review, recent studies on hydrolysis as well as their effects on the biohydrogen production performance are summarized.

• 한국미생물·생명공학회지
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• 제36권2호
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• pp.149-157
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• 2008

Many proteins consist of distinctive domains that can act independently or cooperatively to achieve a unique function. As these domains evolve from a naturally existing repertoire of functional domains, this implies that domain organization is an intrinsic element involved in building the complex structure and function of proteins. Thus, identifying functional domains would appear to be critical to the elucidation of questions related to protein evolution, folding, and the engineering of hybrid proteins for tai- lored applications. However, the simple application of "Lego-like assembly" to the engineering of hybrid proteins is an oversimplification, as many hybrid constructs lack structural stability, usually due to unfavorable domain contacts. Thus, directed evolution, along with computational studies, may help to engineer hybrid proteins with improved physico-chemical properties. Accordingly, this paper introduces several approaches to functional hybrid protein engineering that potentially can be used to create modulators of gene transcription and cell signaling, and novel biosensors to analyze biological functions in vivo.

• Interdisciplinary Bio Central
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• 제3권2호
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• pp.8.1-8.6
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• 2011

Background: Thanks to the development of the mathematical/statistical reverse engineering and the high-throughput measuring biotechnology, lots of biologically meaningful genegene interaction networks have been revealed. Steady-state analysis of these systems provides an important clue to understand and to predict the systematic behaviours of the biological system. However, modeling such a complex and large-scale system is one of the challenging difficulties in systems biology. Results: We introduce a new stochastic modeling approach that can describe gene regulatory mechanisms by dividing two (DNA and protein) layers. Simple queuing system is employed to explain the DNA layer and the protein layer is modeled using G-networks which enable us to account for the post-translational protein interactions. Our method is applied to a transcription repression system and an active protein degradation system. The steady-state results suggest that the active protein degradation system is more sensitive but the transcription repression system might be more reliable than the transcription repression system. Conclusions: Our two layer stochastic model successfully describes the long-run behaviour of gene regulatory networks which consist of various mRNA/protein processes. The analytic solution of the G-networks enables us to extend our model to a large-scale system. A more reliable modeling approach could be achieved by cooperating with a real experimental study in synthetic biology.

• 생명과학회지
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• 제18권11호
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• pp.1507-1512
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• 2008

오랜 기간 동안의 연구에도 불구하고 사람에 특이적으로 장티푸스를 유발하는 S. typhi는 실험동물을 대상으로 하는 감염모델이 확립되어 있지 않기 때문에 S. typhi의 병원성 유발기작에 관한 정보는 부족하다. S. typhi Ty2 균주는 최소배지에서 시스테인의 영양요구성을 지닌다. 본 연구에서는 시스테인 영양요구성이, S. typhi Ty2 균주가 실험동물에서 균체형성을 하는데 어떤 영향을 미치는지를 조사하기 위해 시스테인 영양요구성을 상보할 수 있는 유전자를 찾고자 하였다. S. typhimurium의 genomic library로 형질전환된 S. typhi 균들 중 시스테인을 함유하지 않은 최소배지에서 생육을 하는 3개의 형질전환 균주를 선별하였으며, 이들 중 2개는 S. typhi의 시스테인 영양요구성을 아주 약하게 상보하였고 하나는 명확하게 시스테인의 영양요구성을 상보하였다. 이 클론에 포함되어져 있는 3개의 ORF의 시스테인 영양요구성을 분석한 결과, STM1490을 가진 클론이 S. typhi의 시스테인 영양요구성을 상보하였다. 비록 S. typhi에도 STM1490에 해당하는 유전자가 존재하지만 S. typhimurium의 STM1490에 해당하는 ORF와 비교하였을 때 2개의 아미노산 잔기가 서로 달랐다. 이들의 차이가 시스테인 영양요구성을 보이는 것은 아닌지 확인하기 위해 Overlapping PCR을 통해 S. typhimurium의 STM1490 아미노산(H229Y, C246W)을 치환하였다. 아미노산을 바꾼 돌연변이체도 역시 시스테인 영양요구성을 상보할 수 있어서 아미노산의 차이는 아닌 것을 확인되었으므로 그 외의 다른 인자들이 영양요구성에 관여하는 것으로 추정되었고 후속연구에서 그인자를 찾을 수 있을 것으로 생각된다.

• 식물분류학회지
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• 제47권1호
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• pp.51-93
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• 2017

동해안 석호는 해수와 담수가 섞인 독특한 형태의 기수호이며, 수변식생이 발달되어 생물다양성이 풍부한 지역이다. 본 연구는 국내에 분포하는 17개소의 석호에 대한 식물상과 식물 종조성 등의 조사를 통하여 석호 식생에 대한 안정적인 보전계획 수립을 위한 기초자료를 제시하고자 한다. 17개소의 석호에 대한 식물상 조사결과, 관속식물은 118과 378속 655종 13아종 46변종 6교잡종, 총 720분류군이 확인되었다. 이중에서 한반도 고유종이 11분류군, 멸종우려 식물이 18분류군, 식물구계학적 특정식물인 IV-V등급 식물이 23분류 군이었다. 남방계식물은 4분류군, 북방계식물은 8분류군으로 조사되었고, 특히 남한 내 희귀식물인 갯활량나물(Thermopsis lupinoides), 기름당귀(Ligusticum hultenii), 벼룩아재비(Mitrasacme alsinoides), 통발(Utricularia australis), 검정납작골풀(Juncus fauriei), 새방울사초(Carex vesicaria), 천도미꾸리광이(Puccinellia kurilensis) 등이 동해안 석호에서 생육하고 있었다. 외래식물은 96분류군이 발견되었다. 한반도 석호는 식물다양성이 풍부하고, 희귀식물 및 식물지리학적 중요한 식물이 관찰된다. 석호의 효과적인 관리와 생물다양성 보전을 위해 체계적인 사항들이 논의되었다.

• 한국약용작물학회지
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• 제24권2호
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• pp.143-151
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• 2016

Background: The public has increasing concerns about herbal crops owing to insufficient information on biological hazards such as foodborne pathogens. Therefore, the objective of this study is the development of a herbal crop quality control system through monitoring with biological hazard analysis. Today, it is estimated that millions of people become ill every year from food contamination. The public demands agricultural products of stable and consistent quality. Governments have the responsibility of establishing the standards, legislation and enforcement programs necessary to control food quality and safety. However, research on the biosafety of herbal crop products is still insufficient. Therefore, the implementation of monitoring systems with high standards is critical for public safety. Methods and Results: In this study, we collected 52 samples of herbal crop products, and conducted both quantitative and qualitative biological hazard analysis. With biological hazard analysis, aerobic bacteria, Staphylococcus aureus, Salmonella spp., Escherichia coli, Coliforms, and Listeria spp. could be detected. Conclusions: Herbal crops were found to be contaminated with aerobic bacteria at $3.69{\pm}0.32log\;CFU/g$. Staphylococcus aureus, Salmonella spp., Escherichia coli, Coliforms, and Listeria spp. were not detected in any of the samples. This research suggests that continuous monitoring of biological hazards is required to improve the quality of herbal crops.

• Animal cells and systems
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• 제8권3호
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• pp.213-220
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• 2004

MicroRNA and siRNA (small interfering RNA), representative members of small RNA, exert their effects on target gene expression through association with protein complexes called miRNP (microRNA associated ribonucleoproteins) and RISC (RNA induced silencing complex), respectively. Although the protein complexes are yet to be fully characterized, human EIF2C2 protein has been identified as a component of both miRNP and RISC. In this report, we raised antiserum against EIF2C2 in order to begin understanding the protein complexes. An immunoblot result indicates that EIF2C2 protein is ubiquitously expressed in a variety of cell lines from human and mouse. EIF2C2 protein exists in both cellular compartments, as indicated by an immunoblot assay with a nuclear extract and a cytosolic fraction (S100 fraction) from HeLa S3 lysate. Depletion of EIF2C1 or EIF2C2 protein resulted in a decrease of microRNA, suggesting a possible role of these proteins in microRNA stability or biogenesis. We also prepared antiserum against dsRNA binding protein PACT, whose homologs in C. elegans and Drosophila are known to have a role in the RNAi (RNA interference) pathway. The expression of PACT protein was also observed in a wide range of cell lines.

• 한국환경과학회지
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• 제21권8호
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• pp.989-996
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• 2012

Nitrate contamination of water environments can create serious problems such as eutrophication of rivers. Conventional biological processes for nitrate removal by heterotrophic denitrification often need additional organic substrates as carbon sources and electron donors. We tried to accelerate biological denitrification by using bioelectrochemical reactor (BER) in which electrode works as an electron donor. Denitrification activity of 8 environmental samples from various sediments, soils, groundwaters, and sludges were tested to establish an efficient enrichment culture for BER. The established enrichment culture from a soil sample showed stable denitrification activity without any nitrite accumulation. Microbial community analysis by using PCR-DGGE method revealed that dominant denitrifiers in the enrichment culture were Pantoea sp., Cronobacter sakazakii, and Castellaniella defragrans. Denitrification rate ($0.08kg/m^3{\cdot}day$) of the enrichment culture in BER with electrode poised at -0.5 V (vs Ag/AgCl) was higher than that ($2.1{\times}10^{-2}kg/m^3{\cdot}day$) of BER without any poised potential. This results suggested that biological denitrification would be improved by supplying potential throughout electrode in BER. Further research using BER without any organic substrate addition is needed to apply this system for bioremediation of water and wastewater contaminated by nitrate.

• Animal cells and systems
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• 제15권4호
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• pp.301-309
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• 2011

Charcot-Marie-Tooth disease (CMT) is clinically heterogeneous hereditary motor and sensory neuropathies with genetic heterogeneity, age-dependent penetrance, and variable expressivity. Rare copy number variations by nonrecurrent rearrangements have recently been suggested to be associated with Charcot-Marie-Tooth 1A (CMT1A) neuropathy. In our previous study, we found three Korean CMT1A families with rare copy number variations (CNVs) on 17p12 by nonrecurrent rearrangement. Careful clinical examinations were performed in all the affected individuals with rare CNVs (n=19), which may be the first full study of a subject from a large CMT1A family with nonrecurrent rearrangement. The clinical phenotype showed no significant difference compared with common CMT1A patients, but with variable phenotypes. In particular, a broad intrafamilial phenotypic spectrum was observed within the same family, which may suggest the existence of a genetic modifier. This study may broaden the understanding of the role of CNVs in the pathogenesis of CMT.

• Animal cells and systems
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• 제13권3호
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• pp.275-281
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• 2009

The effects of pentylenetetrazol (PTZ), a GABA receptor antagonist, were studied on passive avoidance learning and expression of heat shock protein 70 (hsp70), neuroglobin, and fatty acid binding protein-7 (fabp-7) genes. Zebrafish were trained to stay in a dark compartment to avoid a weight dropping in an acryl shuttle box with a central sliding door. In two training sessions of 2 h interval, each consisting of 3 trials, the crossing time was significantly increased from $43.2{\pm}14.4s$ to $149.3{\pm}38.5s$ in the first training session and remained $116.1{\pm}36.0s$ s in the first trial of the second training session in the control. In zebrafish treated with PTZ before the first training session, the crossing time was significantly increased neither in the first nor in the second training session. However, the increased crossing time was maintained in the second training session when 10 mM PTZ was treated three times for 10 min at 30 min intervals between the first and second training session. Quantitative real-time PCR showed that expression level of hsp70 mRNA increased two to eight fold over that of control in the brain at 0-24 h after termination of PTZ treatment. No change in expression of neuroglobin and fabp-7 mRNA was shown in PTZ-treated zebrafish. Our studies suggest that PTZ impairs learning ability in avoidance response and also modifies expression of genes related to the neuroprotection.