• Smart Structures and Systems
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• 제7권3호
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• pp.213-222
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• 2011

The native extracellular matrix (ECM) consists of an integrated fibrous protein network and proteoglycan-based ground (hydrogel) substance. We designed a novel electrospinning technique to engineer a three dimensional fiber-hydrogel composite that mimics the native ECM structure, is injectable, and has practical macroscale dimensions for clinically relevant tissue defects. In a model system of articular cartilage tissue engineering, the fiber-hydrogel composites enhanced the biological response of adult stem cells, with dynamic mechanical stimulation resulting in near native levels of extracellular matrix. This technology platform was expanded through structural and biochemical modification of the fibers including hydrophilic fibers containing chondroitin sulfate, a significant component of endogenous tissues, and hydrophobic fibers containing ECM microparticles.

• 대한수의학회지
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• 제30권2호
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• pp.187-192
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• 1990

돼지로부터 분리한 Staphylococcus hyicus subsp hyicus 489주의 protein A 존재여부와 함량을 indirect hemagglutination 및 enzyme-linked immunosorbent assay(ELISA)법으로 조사하였다. Indirect hemagglutination text에 의하여 cell-bound protein A 및 extracellular protein A 보유균은 489주 중 각각 87.7% 및 36.0%로 나타났다. ELISA법에 의한 이들 균의 protein A함량 측정에서 전균주의 extracellular protein A는 1ng/ml미만이었으며, cell-bound protein A함량은 대부분의 균주에서 1ng/ml 미만이었고 11주가 25~108ng/ml 수준이었다.

• 대한한의학회지
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• 제23권1호
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• pp.1-10
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• 2002

Objectives: Uncariae Ramulus Et Uncus extract is clinically used in Korea to treat ischemic cerebral damage. The present study was undertaken to study the neuroprotective effect of Uncariae Ramulus Et Uncus extract in middle cerebral artery occlusion (MCAO) rats. Methods: Changes of extracellular levels of dopamine, DOPAC, HVA. and HIAA in striatum were collected at 20 minutes interval by in vivo microdialysis and then analyzed by HPLC (high performance liquid chromatography) in rats subjected to permanent focal cerebral ischemia induced by 2 hours of MCAO. Uncariae Ramulus Et Uncus extract was orally administrated before MCAO. Different animals were used for measurement of cerebral infarction volume induced by 24 hours of MCAO with TIC staining and image analysis. Results: Extracellular levels of dopamine decreased after treatment with Uncariae Ramulus Et Uncus extract, while extracellular levels of DOPAC and HVA significantly increased. Cerebral infarction volume also significantly decreased after treatment with Uncariae Ramulus Et Uncus extract. Conclusions: These results provided evidence that Uncariae Ramulus Et Uncus extract can produce a neuroprotective effect on cerebral ischemia by regulating extracellular excitatory neurotransmitters.

• Applied Biological Chemistry
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• 제31권2호
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• pp.187-192
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• 1988

미생물에 의한 단백질 생산과 그의 분비기작에 관한 기초 자료를 얻고자 토양으로 부터 균체외 단백질 생산균주를 분리하고 동정한 결과 Bacillus sp.로 추정 되었다. 선정균주를 3.0%의 glucose와 1.3%의 urea를 첨가한 chemically defined medium에 접종하여 $30^{\circ}C$에서 48시간 배양하였을때 1.2mg/ml의 단백질을 생산 하였고 $CaCO_3$의 첨가로 단백질 생산이 촉진 되었으며 $250{\mu}g/ml$의 cephalexin를 첨가하여 96시간 배양 하였을때 2.0mg/ml의 단백질을 생산 하였다.

• 한국축산식품학회지
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• 제42권2호
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• pp.197-209
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• 2022

Extracellular vesicles (EVs) are nanosized vesicles secreted from cells into the extracellular environment and are composed of a lipid bilayer that contains cargos with biological activity, such as lipids, proteins, mRNAs, and noncoding microRNAs (miRNAs). Due to their biological activity and their role in cell-to-cell communication, interest in EVs is rapidly increasing. Bovine milk is a food consumed by people of all ages around the world that contains not only a significant amount of nutrients but also EVs. Milk-derived EVs also exhibit biological activity similar to other source-derived EVs, and studies on bovine milk EVs have been conducted in various research fields regarding sufficient milk production. In particular, not only are the effects of milk EVs themselves being studied, but the possibility of using them as drug carriers or biomarkers is also being studied. In this review, the characteristics and cargo of milk EVs are summarized, as well as their uptake and stability, efficacy and biological effects as carriers, and future research directions are presented.

• 한국균학회지
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• 제51권4호
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• pp.265-276
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• 2023

본 연구는 담수 환경에서 분리한 곰팡이의 특성을 알아보기 위해 효소 활성을 평가하였다. 40개의 곰팡이들은 다양한 담수 시료로부터 분리되었으며, 계통분석을 통해 동정하였다. 실험에 사용된 균주들은 최근에 국내에 보고되었거나, 아직 보고되지 않은 종으로서 이에 대한 특성 정보가 거의 알려지지 않았다. 본연구에서는 40개 균주를 대상으로 protease, amylase, lipase, cellulase, laccase, chitinase의 효소에 대해서 활성을 검정하였다. 대부분의 균주가 laccase 활성을 보였으며, protease, amylase 순으로 높게 나타났다. 담수 환경에서의 효소 활성 정보는 이들의 생태적 역할을 이해하고 산업적으로 활용하는데 기여할 수 있을 것이다.

• Journal of Microbiology and Biotechnology
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• 제18권10호
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• pp.1648-1654
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• 2008

Superoxide dismutase (SOD) removes damaging reactive oxygen species from the cellular environment by catalyzing the dismutation of two superoxide radicals to hydrogen peroxide and oxygen. Extracellular superoxide dismutase (EC-SOD) is a tetramer and is present in the extracellular space and to a lesser extent in the extracellular fluids. Increasing therapeutic applications for recombinant human extracellular superoxide dismutase (rEC-SOD) has broadened interest in optimizing methods for its purification, with a native conformation of tetramer. We describe a solid phase refolding procedure that combines immobilized metal affinity chromatography (IMAC) and gel filtration chromatography in the purification of rEC-SOD from Escherichia coli. The purified rEC-SOD tetramer from the $Ni^{2+}$-column chromatography is refolded in Tris buffer. This method yields greater than 90% of the tetramer form. Greater than 99% purity is achieved with further purification over a Superose 12PC 3.2/30 column to obtain the tetramer and specific activities as determined via DCFHDA assay. The improved yield of rEC-SOD in a simple chromatographic purification procedure promises to enhance the development and therapeutic application of this biologically potent molecule.

• Mycobiology
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• 제33권1호
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• pp.23-29
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• 2005

The effects of different concentrations of three amino acids as carbon and or nitrogen sources on mycelial dry weights, changes in pH values of synthetic medium, ammonia secretion and extracellular protease activity by three zoosporic fungi, pathogens of fish and shellfish, were studied. As compared with the control, the addition of isoleucine and aspartic acid as nitrogen sources were generally stimulative for mycelial dry weight production whereas phenylalanine was inhibitory irrespective to the tested fungal species. When amino acids served as carbon and nitrogen sources, the mycelial dry weights of the three fungi were increased (mostly non-significantly) relative to untreated control but weights were decreased as the concentrations of the three amino acids raised. The addition of individual amino acids as carbon and nitrogen sources to the medium significantly increased pH values of the medium comparable to the control. The addition of each of the three amino acids as carbon and nitrogen sources to the medium significantly induced ammonia secretion by the three species of zoosporic fungi. Ammonia secretion in synthetic medium amended with amino acids as nitrogen source raised by the three zoosporic fungi relative to untreated control except in case of Achlya racemosa treated with isoleucine. Extracellular protease activity was almost promoted in case of Achlya proliferoides and Saprolegnia furcata cultures treated with isoleucine and aspartic acid individually in presence of glucose and vice versa in case of phenylalanine. However, extracellular protease activity of A. racemosa decreased compared with the control at various concentrations of isoleucine and both phenylalanine and aspartic acid assumed inconsistent effects. Extracellular protease activity of the three zoosporic fungi in the medium devoid of glucose varied depending upon zoosporic fungal species, the tested amino acid and the applied concentrations. The values of protease activity were approximately less two folds than that obtained in presence of glucose.

• 식물조직배양학회지
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• 제22권1호
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• pp.15-28
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• 1995

보리의 내동성기작에 관여할 것으로 예상되는 반결빙단백질을 분리하기 위해서 저온순화기간 중에 세포밖 공간에 축적되는 단백질을 분리 및 비교하였다. 42일간의 저온처리를 통해 70, 21, 16, 14 KDa의 단백질과 10 KDa 이하의 연속된 크기의 단백질들의 축적이 증가됨을 확인하였다. 이들 단백질들은 3일간의 저온처리에서도 어느 정도 축적되었으나, 42일간의 처리시 그 양에 있어서 더욱 증가됨을 볼 수 있었다. 위 방법으로 얻어진 단백질을 전체 잎조직의 단백질과 비교하여 세포밖 공간의 단백질 추출방법의 정확도를 검증하였다. 또한 호밀의 저온처리시 세포밖 공간에 축적하는 단백질과의 비교를 통해 구성 단백질의 크기에 있어서 차이를 확인하였으나, 호밀과 보리에서 공통적으로 10 KDa 이하의 범위에서 연속적인 크기의 단백질이 축적됨을 볼 수 있었다. 알려진 광어의 반결빙단백질은 크기가 3300에서 33,000 dalton에 이르는 점으로 미루어 보리와 호밀에서 공통적으로 발견되는 10 KDa 이하의 단백질이 반결빙단백질로 작용할 가능성은 매우 높다. Griffith등(1992)은 호밀의 세포밖 공간 단백질중 일부에서 반결빙활성도를 확인하였고 보리와 호밀간의 해당단백질의 전체적인 profile에서의 유사성을 미루어 보리로부터 얻어진 세포밖 공간의 단백질에서 반결빙단백질을 발견할 가능성은 매우 높다.

• Journal of Microbiology and Biotechnology
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• 제18권6호
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• pp.1136-1140
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• 2008

The Rhodopseudomonas palustris KUGB306 hemA gene codes for 5-aminolevulinic acid (ALA) synthase. This enzyme catalyzes the condensation of glycine and succinyl-CoA to yield ALA in the presence of the cofactor pyridoxal 5'-phosphate. The R. palustris KUGB306 hemA gene in the pGEX-KG vector system was transformed into Escherichia coli BL21. The effects of physiological factors on the extracellular production of ALA by the recombinant E. coli were studied. Terrific Broth (TB) medium resulted in significantly higher cell growth and ALA production than did Luria-Bertani (LB) medium. ALA production was significantly enhanced by the addition of succinate together with glycine in the medium. Maximal ALA production (2.5 g/l) was observed upon the addition of D-glucose as an ALA dehydratase inhibitor in the late-log culture phase. Based on the results obtained from the shake-flask cultures, fermentation was carried out using the recombinant E. coli in TB medium, with the initial addition of 90 mM glycine and 120 mM succinate, and the addition of 45 mM D-glucose in the late-log phase. The extracellular production of ALA was also influenced by the pH of the culture broth. We maintained a pH of 6.5 in the fermenter throughout the culture process, achieving the maximal levels of extracellular ALA production (5.15 g/l, 39.3 mM).