• Biomolecules & Therapeutics
• /
• 제26권4호
• /
• pp.380-388
• /
• 2018

Neural stem cells (NSCs) have the ability to self-renew and differentiate into multiple nervous system cell types. During embryonic development, the concentrations of soluble biological molecules have a critical role in controlling cell proliferation, migration, differentiation and apoptosis. In an effort to find optimal culture conditions for the generation of desired cell types in vitro, we used a microfluidic chip-generated growth factor gradient system. In the current study, NSCs in the microfluidic device remained healthy during the entire period of cell culture, and proliferated and differentiated in response to the concentration gradient of growth factors (epithermal growth factor and basic fibroblast growth factor). We also showed that overexpression of ASCL1 in NSCs increased neuronal differentiation depending on the concentration gradient of growth factors generated in the microfluidic gradient chip. The microfluidic system allowed us to study concentration-dependent effects of growth factors within a single device, while a traditional system requires multiple independent cultures using fixed growth factor concentrations. Our study suggests that the microfluidic gradient-generating chip is a powerful tool for determining the optimal culture conditions.

• 환경생물
• /
• 제34권2호
• /
• pp.107-115
• /
• 2016

전 세계적으로 원자력 발전소는 442기가 가동 중이며, 62기가 충원될 예정이다. 원자력 발전소의 증가에 따라 방사성 폐기물 유출에 대한 위험성도 증가하였다. 이러한 이유 때문에, 방사성 폐기물의 처리는 인간, 동물, 식물을 포함하는 자연 생태계를 보전하는 관점에서 중요하다. 또한, 방사성 폐기물 유출은 그 지역뿐만 아니라 전 세계적으로 심각한 문제를 야기한다. 본 연구는 입체 배양세포에 방사성 핵종원소(세슘, 스트론튬, 코발트)를 처리하였고 이에 대한 영향력을 확인하였다. 입체 배양 구조체는 아가로오스 하이드로겔을 이용하여 제작했으며 암세포 및 정상세포 (HeLa, HepG2, COS-7)를 사용하여 입체 배양을 실시 하였다. 입체 형태로 세포를 배양한 후 세슘, 스트론튬, 코발트 농도 변화에 따라 세포 생존능력을 분석하였다. 이때 입체 배양세포에서 생존능력이 단층 배양세포 보다 최대 42% 우수한 것을 확인하였다. 입체 배양구조체는 세포가 형태 및 생리학적으로 in vivo환경인 조직과 비슷하게 배양을 가능하게 하였다. 따라서, 입체 배양구조체는 기존의 단층 배양 한계점인 in vivo 환경에 적용시킬 수 없다는 한계를 극복하였다. 본 입체 배양 기술이 중금속 독성평가 및 단시간 내에 다수의 물질 분석을 수행하는 고속 대량 스크리닝 기술에 활용될 것으로 기대한다.

• 한국미생물·생명공학회지
• /
• 제17권4호
• /
• pp.343-348
• /
• 1989

L. erythrorhizon 세포를 polyurethane foam과 함께 증식시킬 경우 shikonin 유도체가 polyurethane에 효과적으로 흡착됨과 동시에 polyurethane을 사용하지 않은 경우와 비교하여 shikonin 생산량이 현저히 증가하였다. 이 같은 증가는 세포를 polyurethane pore에 고정하여 증식시킴으로써 원활한 세포간 접촉을 유지하고 세포 내에 shikonin 농도를 저하시켜shikonin 생성에 좋은 조건을 제공함에 기인한 것으로 생각되었다. 공정의 생산성을 높이기 위하여 여러가지 배양시스템이 검토되었는데, indole-3-acetic acid(1.75mg/ι)와 kinetin(0.1mg/ι)을 함유하는 Schenk-Hildebrandt 배지 (SHIK 배지) 시스템이 가장 효과적이었다. p-Chlorophenoxyacetic acid (2.0 mg/ι)와 kinetin (0.1 mg/ι)를 함유하는 Schenk-Hildebrandt 배지 (SHND 배지) 시스템에 비교하여 SHIK 배지 시스템에서 Shikonin 생성량은 약 4.5배 증가하였다. Polyurethane을 세포를 고정화하는 지지체로 사용할 경우에는 현재 행하여지고 있는 2단계 배양보다 1단계 배양이 더욱 효과적이며 경제적으로도 매우 유리할 것으로 판단되었다.

• Journal of Plant Biotechnology
• /
• 제4권1호
• /
• pp.23-27
• /
• 2002

To establish an in vitro mass production system of grape anthocyanin pigments through callus and cell suspension culture, the effects of nitrogen source and sucrose on fresh weight and anthocyanin production in cell suspension culture of 'Sheridan' grape level were studied. When the medium was devoid of $NO_3^-$, cell fresh weight was either remained stable (1% sucrose) or slightly decreased with culture time (2,3, and 4% sucrose). When $NH_4^-$ was lacking, 3% sucrose was most favorable for cell growth. When $NH_4^-$ was supplied as N source, the anthocyanin content of 2% sucrose containing medium was maintained 2 times higher than other levels till day 8 in culture, then that of 3 and 4% sucrose which peaked at day 12 thereafter. The anthocyanin content was low than $NO_3^-$-free media. Total anthocyanin content in $NH_4^-$-free medium was just about a half of that of $NH_4^+$ medium. Anthocyanin production of 2% sucrose in $NH_4^+$ medium was maintained about 3-fold till day 8, then decreased thereafter. In $NH_4^+$ medium, pH decreased gradually with final pH of 3.5 to 4.0, while pH in $NH_4^+$-free medium increased with final pH of 6.5 to 7.5.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2003년도 생물공학의 동향(XII)
• /
• pp.223-227
• /
• 2003

Mevinolic acid (MA), a secondary metabolite produced by a filamentous fungus Aspergillus terreus, is acidic form of lovastatin which has been identified as a powerful cholesterol-lowering agent in humans. When immobilized cell culture was performed, MA production was about 5.3-fold higher than the parallel suspended cell culture. Although the immobilized cells proliferated slowly during exponential in comparison with the suspended cells, oxygen uptake rate and oxygen mass transfer coefficient of the immobilized cell culture were about 1.3- and 2.5- fold higher respectively than those of the parallel suspended cell culture. From these results, it was concluded that MA biosynthesis was closely dependent on the cell growth rate, morphology and oxygen availability.

• Asian-Australasian Journal of Animal Sciences
• /
• 제20권7호
• /
• pp.1015-1022
• /
• 2007

The spermatogonial stem cell (SSCs) is unique in that it is the only cell in the adult male that can contribute genes to a subsequent generation. Permanent modification of the germ cell line may be realized if stem cells could be cultured, transfected with unique genes, and then transplanted into recipient testes. We developed a culture system that supported long-term viability of SSCs. We used a retrovirus vector (pMSCV including ${\beta}$-galactosidase) to stably transfect spermatogonia following long-term culture using the system developed. Expression of the reporter gene ${\beta}$-galactosidase controlled by the retroviral vector was stable in long-term cultured SSCs. We confirmed the retroviral-mediated ${\beta}$-galactsidase gene could be expressed in germ cells in recipient mice following SSCs transplantation.

• Journal of Microbiology and Biotechnology
• /
• 제19권12호
• /
• pp.1603-1611
• /
• 2009

High-cell-density cultivation of yeast was investigated using the agricultural waste products corn steep liquor (CSL) and molasses. The Saccharomyces cerevisiae KV-25 cell mass was significantly dependent on the ratio between C and N sources. The concentrations of molasses and CSL in the culture medium were statistically optimized at 10.25% (v/v) and 16.87% (v/v), respectively, by response surface methodology (RSM). Batch culture in a 5-l stirred tank reactor using the optimized medium resulted in a cell mass production of 36.5 g/l. In the fed-batch culture, the feed phase was preceded by a batch phase using the optimized medium, and a very high dried-cell-mass yield of 187.63 g/l was successfully attained by feeding a mixture of 20% (v/v) molasses and 80% (v/v) CSL at a rate of 22 ml/h. In this system, the production of cell mass depended mainly on the agitation speed, the composition of the feed medium, and the glucose level in the medium, but only slightly on the aeration rate.

• Journal of Microbiology and Biotechnology
• /
• 제10권3호
• /
• pp.321-326
• /
• 2000

To examine the feasibility of the long-term production of the human granulocyte colony stimulating factor (hG-CSF) using the $_{L}-arabinose$ promoter system of Escherichia coli, flask relay culture and cyclic fed-batch culture were performed. In the flask relay culture, it was found that the pismid was maintained stably up to about 170 generations in an uninduced condition, whereby the cells could also maintain the capability of expressing hG-CSF expression were maintained stably up to at least 100 generations. In contrast, in the cyclid fed-batch culture, segregational plasmid instability was observed within about 4 generations after induction, even though the cell growth and hG-CSF production reached their maximum balues, 78.0 g/l of dry cell weight and 7.0 g/l of hG-CSF, respectively. It would appear that, when compared to the flask relay culture, the high-cell density and high-level expression of hG-CSF in the cyclic fed-batch cultrure led to the segregational plasmid instability; in other words, a severe metabolic burden existe on the cells due to the high-level expression of hG-CSF. Accordingly, based on these long-term cultures, the segregational and structural plasmid instability was observed and a strategy to overcome such problems could be designed.

• Journal of Microbiology and Biotechnology
• /
• 제18권7호
• /
• pp.1252-1256
• /
• 2008

Cell recycled culture of succinic acid-producing Anaerobiospirillum succiniciproducens was anaerobically carried out using an internal membrane filter module in order to examine the physiological response of A. succiniciproducens to a high-cell-density environment. The optimal growth of A. succiniciproducens and its enhanced succinic acid productivity were observed under $CO_2$-rich conditions, established by adding $NaHCO_3$ and $Na_2CO_3$, in the cell recycled system. A. succiniciproducens grew up to 6.50 g-DCW/l, the highest cell concentration obtained so far, in cell recycled cultures. The cells did not change their morphology, which is known to be easily changed in unfavorable or stress environments. The maximum productivity of succinic acid was about 3.3 g/l/h, which is 3.3 times higher than those obtained in batch cultures. These results can serve as a guide for designing highly efficient cell recycled systems for succinic acid at a commercial level.

• 한국식물학회:학술대회논문집
• /
• 한국식물학회 1987년도 식물생명공학 심포지움 논문집 Proceedings of Symposia on Plant Biotechnology
• /
• pp.213-237
• /
• 1987

In vitro flowering system may minimize the confounded influence of non-floral meristem parts of plants in studying the relationship of a given treatment and flowering responses. We have induced flower buds from plantlets regenerated from zygotic embryo-derived somatic embryos of ginseng, which circumvented the normal 2-year juvenile period before flowering. The result suggests that the adulthood of ginseng root explants in the experiment previously conducted by Chang and Hsing (1980; Nature 284: 341-342) is not prerequired to flowering of plantlets regenerated through somatic embryogenesis. We have also induced flower buds from elongated axillary brandches from cotyledonary nodes by culturing ginseng zygotic embryos, seedlings, and excised cotyledonary nodes. It was found that 6-benzyladenine (BA) supplemented to the medium was essential for flowering, whereas abscisic acid (ABA) was inhibitory. Gibberellic acid(GA3) was also required for flowering when ABA was present with BA in the medium. The results suggest that cytokinins, gibberellins, and inhibitors play primary, permissive, and preventive roles, respective-ly, in the induction of flowering of ginseng. Tran Thanh Van (1980; Int. Rev. Cytol., Suppl. IIA: 175-194) has developed the "thin cell layer system" in which the induction of shoots, roots, or flower buds from epidermal layer explants were controlled by culture conditions and exogenous growth regulators in the medium, Utilizing the thin cell layer system, Meeks-Wagner et al. (1989; The Plant Cell 1: 25-35) have cloned genes specifically expressed during floral evocation. However, the system is too tedious for obtaining a sufficient amount of plant materials for biochmical and molecular biological studies of flowering. We have developed a garlic callus culture system and one obvious advantaging over the thin cell layer system is that an abundant cells committed to develope into flower buds proliferate. When the above cells were compared by two-dimensional gel electrophoresis with those which have just lost the competence for developing into flower buds, a few putative proteins specific to floral evocation were detected. The garlic callus culture system can be further explored for elucidation of the molecular biological mechanism of floral evocation and morphogenesis.hogenesis.