• Korean Journal of Plant Tissue Culture
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• v.28 no.2
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• pp.103-108
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• 2001

The in vitro plantlets of cassava (Manihot esculenta Crantz cv. MColl 22) could be regenerated from nodal explant cultures in a liquid MS basal medium containing 0.01 mg/L zeatin for 2 weeks. The plantlets of 1.5∼2.5 cm in shoot length were transplanted to a glass bottle containing fine sand and acclimated under non-sterile conditions after excising their intact roots by: 1) prune leaving roots base of 1∼1.5 cm; 2) complete removal of roots; and 3) cutting off the rooting zone. The majority of in vitro-formed intact roots continued growth after transferred to soil, and all of the damaged roots stopped further growth. The plantlets with excised roots began to develop new roots within 7∼10 days after being transferred to a glass bottle, and a few of the pruned roots developed lateral roots from the remaining portion. Pruning and removal of in vitro roots resulted in a high survival rate (>87%), and did not significantly affect ex vitro root regeneration and acclimation, but the plantlets in which the rooting zone had been cut-off showed 73% survival rate. Pruning or removal of in vitro roots before transfer of plantlets is recommended for useful method of commercial micropropagation because of easier handling and high survival rate of plantlets.

• Korean Journal of Plant Resources
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• v.16 no.1
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• pp.34-39
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• 2003

Corm apical meristem cultures of thirteen glasshouse freesia cultivars were tested to investigate the possibility of micropropagation using MS basal medium supplemented with 2,4-D, NAA(0.1, 0.5, 1.0mg/L, respectively) and BA (0.5∼2.0mg/L). The majority of the tested cultivars could be induced callus and shoot buds in all culture condition. The combinations of NAA and BA appeared superior to that of 2,4-D and BA depending on cultivars for callus induction and shoot formation. Among the cultivars, 'Golden Yellow' showed the highest regeneration capacity on MS media with 0.5mg/L NAA and 1.0 mg/L BA. The highest percentage of regeneration and the greatest number of shoot from calli were obtained through successive subculture on MS medium supplimented with 0.5mg/L BA. In that condition, more than 60 ％ shoot regeneration and average of 25.1 shoots per explant was achieved. Transformed shoots on half-strength MS medium without plant growth regulators rooted easily.

• Korean Journal of Plant Tissue Culture
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• v.21 no.4
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• pp.247-252
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• 1994

The effects of explant sources, plant growth regulators on callus induction and plantlet differentiation from leaf blade, petiole, and meristem tissue of Pelalgonium citrosa were investigated under illumination or in dark condition Leaf blade explants cultured on Murashige and Skoog's medium containing 2,4-D and kinetin did not form callus or organ. But those cultured on medium with NAA and BA produced callcus and shoots. Dark condition was more effective than light condition to callus induction and showed that some of shoot were differentiated directly from leaf blade explane. Callus proliferated vigorously on meristem tissue after 7 days of culture, and multiple shoots were obtained Sum callus on medium with 0.5 mg/L NAA and BA. Roots formed readily from about 80% of the shoots cultured on medium with 1.0 mg/L NAA. Regenerated plantlets regenerated had phenotypically normal leaves and roots.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2005.05a
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• pp.218-222
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• 2005

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.11a
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• pp.172-173
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• 2001

기내 환경과 소식물체의 생육간 관계를 분석하기 위해서는 정밀 환경 제어가 가능한 시스템이 요구된다. 본 연구에서는 CO₂, PPFD, RH등의 환경 제어 시스템을 개발하고 본 시스템 내에서의 소식물체 생육 특성을 분석하고자 하였다. 본 시스템은 총 5개의 챔버를 부착하여 외부 환경과 밀폐된 조건을 구현하고 독립적으로 제어 가능하도록 설계하였으며, 환경 제어 알고리즘을 완성하였다. (중략)

• Journal of Life Science
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• v.22 no.4
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• pp.538-544
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• 2012

Ethanol is known as being carcinogenic to humans. In addition, the anti-proliferative effects of ethanol have been described for a variety of tissues and cells. In this study, we investigated the anti-proliferative effects of ethanol on various cancer cells, particularly on oncogenic $ras$-transformed or-injected cells. Ethanol treatment inhibited the cell proliferation of normal control cells, but did not suppress the proliferation of various cancer cells and oncogenic $ras$-transformed cells. Furthermore, ethanol treatment did not interfere with DNA synthesis, which was induced by microinjecting the oncogenic $H-Ras^{V12}$ protein. The anti-proliferative effect of ethanol was rescued by antioxidants, such as $N$-acetylcysteine and 4-methlpyrazole. These results suggest that ethanol cytotoxicity is exerted through free radical formation, and that the anti-proliferative action site of ethanol cytotoxicity either lies upstream, or is independent of Ras.

• Tuberculosis and Respiratory Diseases
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• v.63 no.3
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• pp.242-250
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• 2007

Background: Abnormal angiogenesis can induce hypoxia within a highly proliferating tumor mass, and these hypoxic conditions can in turn create clinical problems, such as resistance to chemotherapy. However, the mechanism by which hypoxia induces these changes has not yet been determined. Therefore, this study was conducted to determine how hypoxia induces changes in cell viability and extracellular microenvironments in an in vitro culture system using non-small cell lung cancer cells. Methods: The non-small cell lung cancer cell line, A549 was cultured in DMEM or RPMI-1640 media that contained fetal bovine serum. A decrease in the oxygen tension of the media that contained the culture was then induced in a hypoxia microchamber using a $CO_2-N_2$ gas mixture. A gas analysis and an MTT assay were then conducted. Results: (1) The decrease in oxygen tension was checked the anaerobic gas mixture for 30 min and then reoxygenation was induced by adding a 5% $CO_2-room$ air gas mixture to the chamber. (2) Purging with the anaerobic gas mixture was found to decrease the further oxygen tension of cell culture media. (3) The low oxygen tension resulted in a low pH, lactic acidosis and a decreased glucose concentration in the media. (4) The decrease in glucose concentration that was observed as a result of hypoxia was markedly different when different types of media were evaluated. (5) The decrease in oxygen tension inhibited proliferation of A549 cells. Conclusion: These data suggests that tumor hypoxia is associated with acidosis and hypoglycemia, which have been implicated in the development of resistance to chemotherapy and radiotherapy.

• Korean Journal of Veterinary Research
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• v.28 no.2
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• pp.379-385
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• 1988

For the comparison of surface fine structures in the proliferative forms of two major protoroan parasites, Toxoplasma gondii and Sarcocystis species in mammalian hosts, isolated from the artificially infected mice and from the naturally infected cattle, respectively, an SEM(Hitachi S-570) was applied to the fixed, dried and coated with gold ion on the microslide glasses. The tachyzoites of T gondii from the peritoneal cavity of the mouse showed the crescent-like feature and measured as $5.57{\mu}m$ in length and $2.33{\mu}m$ in width, while the bradyzoites of Sarcocystis species from the heart muscle of slaughtered cattle was banana-shaped and measured as $14.18{\mu}m$ in length and $2.85{\mu}m$ in width. On the surface of Sarcocystis species bradyzoite, a distinct elliptical micropore was identified in the high magnification observation of 60,000X, and it measured as $0.35{\mu}m$ in length and $0.18{\mu}m$ in width.

• Journal of Life Science
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• v.28 no.3
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• pp.345-350
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• 2018

This study examines the role of six species of microalgae, including Phaeodacylum tricrnutum (PT), Chaetoceros gracilis (CG), Nanochloris oculata (NO), Pavlova lutheri (PL), Chlorella ellipsoidae (CE), and Scendedemus obliquus (SO), on hair loss prevention and scalp improvement. To determine the effects of microalgae extracts on hair loss prevention and scalp improvement, antioxidant activity, cell proliferation in HaCaT cells and HFDPC cells, and the inhibition level of 5-alpha reductase activity were examined. In the study of antioxidant activity, the $EC_{50}$ values of DPPH anti-radical activities indicated that the SO, CG, and ST9 treatment groups demonstrate significant antioxidant activity. In the study of the hydroxyl radical scavenging activity, CG (6.6~42.1%), ST9 (26.0~44.0%), and SO (7.8~44.3%) demonstrated significant effects. Furthermore, SO promoted the proliferation of HaCaT cells and a human epidermal cell line during a 6-day treatment. In the study of the proliferation of HFDPC cells, a hair follicle dermal papilla cell line, CG, and SO significantly stimulated cell proliferation. Finally, PT, CG, and SO significantly inhibited 5-alpha reductase activity. These results suggest that among the six microalgae used in this study, CG and SO have antioxidant effects, induce cell proliferation, inhibit 5-alpha reductase activity, and can be used for hair loss prevention and scalp improvement.

• Korean Journal of Environmental Biology
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• v.28 no.3
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• pp.172-178
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• 2010

The bloom of the genus Stephanodiscus was gradually extinguished after 18 April. Counts of bacterial population were increased as the diatom bloom was disappeared. Numbers of the heterotrophic nanoflagellates and ciliates were also increased during the disappearance of the bloom. The densities of the mesozooplankton, the major predator of the diatoms, started to increase in April. However, their growth was suppressed during the bloom period of the diatoms (from January to March). During the bloom period of the diatoms, the monthly average value of the basic productivity amounted up to 11,765.7 mgC $m^{-2}day^{-1}$, which is relatively high value considering the low temperature and light during that period. The growth rate of phytoplankton in March, when the bloom was beginning to be supressed was 0.007. The growth rate of phytoplankton was negative value in April when the decreasing of the algal density was started.