• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.457-462
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• 2002

Low Electromagnetic Field (EMF) intensity in the range of $1{\mu}T\;to\;10{\mu}T$(Tesla) was found to enhance the growth of CHO cells and the production of tPA in batch and perfusion cultivations. At $1{\mu}T\;intensity,\;1.3{\times}10^7$ viable cells/ml of maximum cell density and 80 mg/l of maximum tPA production were obtained in batch cultivation, compared to $2.8{\times}10^6$ viable cells/ml and 59 mg tPA/1 in unexposed case (control). A similar trend was observed in the perfusion process, where it was possible to obtain $1.2{\times}10^7$ viable cells/ml of maximum cell density and 81 mg tPA/l of maximum tPA production by more than 80 days of cultivation. However, there was not much difference between $1{\mu}T\;and\;10{\mu}T$ in perfusion cultivation, possibly due to better environmental growth conditions being maintained by continuous feeding of fresh medium into the reactor. On the contrary, both cell growth and tPA production were severely inhibited at higher than 1 mT intensity, showing no growth at 10 mT exposure. Specific growth rate was linearly correlated to specific tPA production rate at $1{\mu}T$EMF intensity, which represents a partially growth-related relationship. It was also found that a large amount of $Ca^2+$ was released at low EMF intensity, even though the cell growth was not much affected. Low EMF intensity significantly improved both cell growth and tPA production, and tPA production seemed to be more affected than the cell growth, possibly due to the changes of cell membrane characteristics. It can be concluded that the elaboration of EMF intensity less than $10{\mu}T$ could improve cell growth and tPA production, but mainly tPA secretion through batch or perfusion process in a bioreactor.

• 한국미생물·생명공학회지
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• 제24권1호
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• pp.126-131
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• 1996

HL-60 was cultivated to produce tPA (tissue-type plasminogen activator) and study the mechanism of cell death. Maximum cell density and tPA production were obtained as $5.27{\times}10^6$ cells/ml and 324ng/ml, respectively under perfusion cultivation. tPA production was enhanced to 420ng/ml in adding 160nM of phorbol ester. The cells were gradually differentiated to granulocytes rather than proliferation. By Fluorescent microscope, apoptosis was prevailed except the death phase and in high agitation speed, but necrosis was prevailed in thawed cells and during the latter periods of the cultivation. It was also proved that tPA was most produced in apoptosis. To obtain higher tPA productivity, the cells must be maintained in apoptosis, not necrosis phase when the cells were dying.

• Tuberculosis and Respiratory Diseases
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• 제70권5호
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• pp.405-415
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• 2011

Background: In an effort to find alternative therapeutic agents to prevent excessive fibrosis as a sequela to complicated parapneumonic effusion or empyema, we examined the effect of tissue plasminogen activator (tPA) as a fibrinolytic agent combined with talc or transforming growth factor (TGF)-${\beta}1$ in a human pleural mesothelial cell line, MeT-5A. Methods: MeT-5A cells were stimulated with various doses of talc, doxycycline or TGF-${\beta}1$ for 24 h and then were treated with tPA for an additional 24 h. Cell viability was measured by MTT assay. The production of interleukin (IL)-8 and vascular endothelial growth factor (VEGF) in the culture supernatants was measured by ELISA. Real-time PCR was carried out for measurement of type I collagen mRNA. Results: MeT-5A cells treated with talc showed a dose-dependent increase in production of IL-8. Talc also increased production of type I collagen mRNA at low doses, but talc did not influence the induction of VEGF. Addition of tPA to talc-stimulated cells showed further increases in the production of IL-8, but tPA did not influence the production of VEGF or type I collagen mRNA. TGF-${\beta}1$ increased the production of both VEGF and collagen type I mRNA, both of which were effectively inhibited by additional tPA treatment in MeT-5A cells. Conclusion: TGF-${\beta}1$ is a potent inducer of collagen synthesis without induction of IL-8 in MeT-5A cells. Addition of tPA after TGF-${\beta}1$ stimulation inhibited further fibrosis by direct inhibition of collagen mRNA synthesis as well as by inhibition of VEGF production.

• Biotechnology and Bioprocess Engineering:BBE
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• 제1권1호
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• pp.32-35
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• 1996

Amoving aeration-membrane (MAM) bioreactor was employed for the production of 2$\mu$g/mL of tissue type Plasminogen Activator (tPA)in serum free medium from normal human fibroblast cells. This system could maintain high cell density for long periods of steady state conditions in perfusion cultivation. Under normal operating condition, shear stress was as low as 0.65 dynes/$\textrm{cm}^2$ at the agitation speed of 80 rpm. Even though cell density gradually decreased with increasing agitation speed, tPA production increased linearly with increasing shear stress within a moderate range. This culture system allowed production of 2$\mu$g tPA/mL while maintaining a high cell denisty of 1.0$\times$107 viable cell/mL.

• Journal of Microbiology and Biotechnology
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• 제6권4호
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• pp.295-298
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• 1996

Under glutamine-limited condition, $2\times10^6$ (viable cells/ml) of maximum cell density and 13.5 ($\mu g$/ml) of tissue-type Plasminogen Activators (tPA) production were maintained by spike feeding fresh medium in fed-batch cultivation of human recombinant melanoma cells. It showed that tPA production was much seriously affected than cell growth according to initial glutamine concentrations. Above 3.4 (mmol/I) of glutamine concentration both cell growth and tPA production were not much affected by increasing initial glutamine concentration. Glutamine depleted situation was occurred at latter periods of batch and fed-batch cultivations below 5.4 (mmole/I) of initial glutamine concentration. It also showed that maximum glutamine consumption and ammonia evolution rates were closely related to initial glutamine concentrations. Maximum specific tPA production rate was estimated as $8.1\times19^{-6}$ ($\mu g$/cells/h) at 3.4(mmol/I) of glutamine concentration, which is higher than that from other batch and fed-batch processes.

• Reproductive and Developmental Biology
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• 제29권2호
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• pp.75-82
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• 2005

This study were examined whether plasminogen activators (PAs) are produced by porcine fresh or frozen-thawed cumulus-oocytes complexes (COCs) and cumulus cell free-oocytes. In fresh or frozen-thawed COCs and oocytes for 0 hour cultured, no activity of PAs was detected. However, at 24 hours of culture urokinase-type plasminogen activator (uPA) was detected in COCs and denuded oocytes. In the frozen-thawed COCs and cumulus cell free-oocytes cultured for 24 hours, no PAs were observed. After COCs were cultured for 48 hours, tissue-type plasminogen activator (tPA) and tPA-PAI were observed in COCs only. In the frozen-thawed COCs and cumulus cell free-oocytes cultured for 48 hours, no PAs were observed. These results suggest that uPA, tPA and tPA-PAI are produced by porcine COCs, but only uPA by oocytes during maturation for 24 hours. Only tPA, and tPA-PAI are produced by COCs cultured for 48 hours, and no PAs are produced by denuded-oocytes cultured for 48 hours. In all of the frozen-thawed groups, no PAs are observed by COCs and denuded-oocytes.

• Reproductive and Developmental Biology
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• 제30권2호
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• pp.135-141
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• 2006

The present study was conducted to investigate the effects of cumulus cells and porcine follicular fluid (pFF) on plasminogen activator (PA) activity and oocytes maturation in vitro in the pig. The cumulus-oocyte complexes (COCs) and denuded oocytes (DOs) were incubated in NCSU-23 medium with or without 10% pFF for 0, 24, or 48 hr. In the presence of cumulus cells, the proportions of oocytes matured to metaphase-II stage were significantly (P<0.05) higher in medium with pFF than without pFF (69.8 vs. 37.7%, respectively). When COCs and DOs were cultured in the presence of pFF, tissue-type PA (tPA), urokinase-type PA (uPA), and tPA-PA inhibitor (tPA-PAI) were observed in COCs, and PA activities were higher at 48 hr than 24 hr. When COCs and DOs were cultured in the absence of pFF, tPA and tPA-PAI were observed in COCs, and PA activities were increased as duration of culture increased. No PA activities were detected in DOs regardless of pFF supplementation. When porcine oocytes were cultured in the presence of pFF for 24 and 48 hrs, the activities of tPA-PAI, tPA, and uPA were observed in both COCs and DOs. In medium of absence of pFF, PA activities were observed in oocytes with cumulus cells only. On the other hand, three plasminogen-dependent lytic bands (tPA-PAI, tPA, and uPA) were observed in pFF cultures. Particularly uPA activity was higher than the other kinds of PA activity. When oocytes and cumulus cells were separated from porcine COCs at 0 hr of culture, tPA-PAI, tPA, and uPA were detected in cumulus cells at 48 hr of culture, but no PA activities were in DOs. The presence of pFF and cumulus cells in maturation medium stimulated not only nuclear and cytoplasmic maturation in porcine COCs, but also PA production by cumulus cells and COCs. It is possible that PAs produced by cumulus cells migrated through the gap junction between oocyte and cumulus cells. These results suggest that porcine oocytes have no ability to produce PA themselves.

• 한국미생물·생명공학회지
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• 제16권6호
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• pp.522-525
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• 1988

무혈청 배지에 생산촉진제로 30$\mu$g/m$\ell$의 Heparin 을 첨가해 정상인의 섬유 세포로부터 상업적으로 tPA를 생산할 수 있는 방법의 개발과, 효과적인 tPA 생산을 위해 대량 배양에 적합한 무혈청 배지의 조성을 확립했다. 이 방법으로 연속배양 공법하에서 매일 1.1gram의 tPA가 생산될 수 있으며, 이 생산성은 tPA 생산 단가를 크게 낮출 분만 아니라 무혈청 배지의 사용으로 tPA의 순수 정제 과정을 크게 단축시킬 수 있다. 또한 이 세포에서 생산되는 tPA 는 fibrin lysis 시험결과 섬유질 분해능력이 높음이 입증되었으며, ELISA결과와도 상충했다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.257-260
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• 2002

Dissolved oxygen level of cell culture media has a critical effect on cellular metabolism, which governs specific productivity of recombinant proteins and mammalian cell growth However, in the cores of cell aggregates or cell-immobilized beads, oxygen level frequently goes below a critical level. Mammalian cells have a number of genes induced in the lower level of oxygen, and the genes contain a common cis-acting element (-RCGTG-), hypoxia response element (HRE). By binding of hypoxia inducible factor-l (HIF-I) to the HRE, promoters of hypoxia inducible genes are activated, which is a survival mechanism. In this work, to develop a CHO cell capable of producing recombinant proteins in immobilization and high density cell culture efficiently, mammalian expression vectors containing human tissue-type plasminogen activator (t-PA) gene controlled by HRE were constructed and stably transfected into the CHO cells. In $Ba^{2+}$ -alginate immobilization culture, CHO/pCl/dhfr/2HRE-t-PA cells produced 2 folds higher recombinant t-PA activity than CHO/pCl/dhfrlt-PA cells without $CoCl_2$ treatment. Furthermore, in repeated fed batch culture, productivity of t-PA in immobilized CHO/pCI/dhfr/2HRE-t-PA cells was 121 ng/ml/day, total production of 0.968 mg/day at 11 days culture while CHO/pCIIdhfrlt-PA cells was 22.8 ng/ml/day. All these results indicate that HRE is very useful for the enhancement of protein productivity in mammalian cell cultures.

• KSBB Journal
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• 제17권6호
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• pp.582-585
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• 2002

백합(Lilium longiflorum)으로부터 수집한 화분에 대하여 기내배양, Agrobacterium 및 vacuum infiltration과정을 이용한 형질전환 그리고 kanamycin배지에서의 선별배양을 통하여 PCR에 의하여 증폭된 1.7 kb의 human tissue plasminogen activator(tPA) cDNA의 발현을 분석하였다. 16시간 정도 배양한 신장화분관의 western blotting결과, human standard와 유사한 크기로의 발현을 확인하였다. 이로써 백합화분은 신속한 단백질발현의 분석을 위한 일회성 생산숙주로서의 가능성을 제시하고 있다.