• Journal of Life Science
• /
• v.32 no.2
• /
• pp.108-118
• /
• 2022

The subventricular zone (SVZ) in the brain contains neural stem cells (NSCs) that generate new neurons throughout one's lifetime. Many extracellular and intracellular factors that affect cell proliferation and neuronal differentiation of NSCs are already well-known. Recently, L-type calcium channels have been reported to regulate neural development and are present in NSCs, differentiating neuroblasts, and mature neurons in the SVZ. Nifedipine, a blocker of L-type calcium channels, has been long used as a therapeutic drug for hypertension. However, studies on the use of nifedipine to inhibit L-type calcium channels of NSCs are lacking. Herein, we treated NSCs cultured from mouse postnatal SVZ with nifedipine during neuronal differentiation. Nifedipine increased the number of Tuj1-positive neurons but did not significantly change the number of Olig2-positive oligodendrocytes. Nifedipine increased cell division during early differentiation, which was detected using the 5-ethynyl-2'-deoxyuridine incorporation assay and immunocytochemistry assessment by staining the cells with phosphorylated histone H3, a mitosis marker. Nifedipine increased the transcription of Dlx2, a neurogenic transcription factor, and the level of Mash1, a marker for early neurogenesis. In addition to nifedipine, verapamil, which is also an L-type calcium channel blocker, showed a slight increase in neurogenesis, but its statistical significance was very low. In contrast, pimozide, a T-type calcium channel blocker, did not affect neurogenesis, although T-type calcium channel genes Cav3.1, Cav3.2, and Cav3.3 were expressed. In summary, nifedipine might promote the neuronal fate of NSCs during early differentiation and calcium signaling through L-type calcium channels might be involved in neuronal differentiation, especially during the early stages of differentiation.

• Korean Journal of Plant Tissue Culture
• /
• v.25 no.5
• /
• pp.295-299
• /
• 1998

To detect the effects of gelling agent brands and concentration on rice anther culture, anthers of rice(O. sativa L. japonica, cv, Nagdongbyeo) were inoculated on N6-Y1 basic media supplemented with 0.4~1.6% Bacto agar(Difco, 04140-01), Agarose(Sigma, Type 1) and 0.2~0.8% Gelrite(Kelco, 143364) as gelling agents. On 0.4% Bacto agar and Agarose media, the frequency of callus formation which was significantly decreased in proportion to gelling agent's concentration was 39% and 55%, respectively. On 0.6% Gelrite media, the frequency of callus formation which was not statistically significant among the 0.2~0.8% concentration was 44%. Calli derived from the higher concentration of gelling agents showed embryogenic with slow growth, small, whitish and hard shape compare to that of the lower concentration. The frequency of green plant regeneration was high not only in calli derived from the higher concentration but also in plant regeneration medium with the higher concentration after callus transfer. Calli derived from the higher concentration was effective to maintain the frequency of green plant regeneration up to 60 days after anther inoculation. Introduction of 0.6~0.8% Geltite for callus formation, then transferred 1.6% Bacto agar and Agarose or 0.8% Gelrite for green plant regeneration was effective to increase anther culture efficiency.

• Korean Journal of Legislative Studies
• /
• v.24 no.3
• /
• pp.29-54
• /
• 2018

Focusing on vastly different results between two presidential elections in 2012 and 2017, this paper examines how political attitudes of conservative voters had changed in 5 years and how these changes had brought about differences in their vote choices in 2017. Using panel data encompassing two presidential elections, this paper finds that, though ideological and affective evaluation of conservative parties and candidates had indeed deteriorated among supporters of Park Geun-Hye in 2012, it is candidate factors rather partisan ones that exerted much more significant influence on their vote choices in 2017. In addition it is found that the differentiation in political and economic policy preferences among conservative voters had only slight influence on their voted choices in 2017. This paper concludes with discussing how to understand the result of the $19^{th}$ presidential elections and what implications it has in prospecting the party realignment in Korean electoral politics.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.48 no.3
• /
• pp.291-301
• /
• 2021

The aim of this study is to compare the properties of odontoblast gene of early passage cells and late passage cells derived from impacted maxillary supernumerary teeth. Impacted supernumerary teeth with maxilla were extracted from 12 patients (8 males, 4 females) between 6 - 9 years old without medical history. Real-time polymerase chain reaction (PCR) was conducted to compare characterization of odontoblast cell in the 3rd and 10th passage, and between with bone inducing additive group and without additive group. Genes for odontoblasts characteristics are osteonectin (ONT), alkaline phosphatase (ALP), osteocalcin (OCN), dentin matrix protein 1 (DMP-1) and dentin sialophosphoprotein (DSPP). The level of gene expression was in a decreasing order of ONT, ALP, OCN, DMP-1 and DSPP in the 3rd passage, and in decreasing order of ONT, DMP-1, OCN, ALP, and DSPP in the 10th passage in the undifferentiation and differentiation group. The order of ONT, DMP-1, and OCN did not changed. ALP and DMP-1 were switched in order. ALP and DMP-1 may be used as important markers for differentiating between the 3rd passage and 10th passage cells. Considering that supernumerary tooth was extracted young age and the time required to cultured 10th passage was short, supernumerary tooth can be considered a useful donor site of dental pulp stem cells.

• Journal of Life Science
• /
• v.28 no.12
• /
• pp.1397-1405
• /
• 2018

Mitochondria have multiple functions in cells: providing chemical energy, storing cellular $Ca^{2+}$, generating reactive oxygen species, and regulating apoptosis. Through these functions, mitochondria are also involved in the maintenance, proliferation, and differentiation of stem/progenitor cells. In the brain, the subventricular zone (SVZ) is one of the neurogenic regions that contains neural stem cells (NSCs) throughout a lifetime. However, reports on the role of mitochondria in SVZ NSCs are scarce. Here, we show that rotenone, a complex I inhibitor of mitochondria, inhibits the proliferation and differentiation of SVZ NSCs in different ways. In proliferating NSCs, rotenone decreases mitosis as measured through phosphorylated histone H3 detection; moreover, apoptosis is not induced by rotenone at 50 nM. In differentiating NSCs, rotenone blocks neurogenesis and oligodendrogenesis while glial fibrillary acidic protein-positive astrocytes are not affected. Interestingly, in this study there were more cells in the differentiating NSCs treated with rotenone for 4-6 days than in the vehicle control group which was a different effect from the reduced number of cells in the proliferating NSCs. We examined both apoptosis and mitosis and found that rotenone decreased apoptosis as detected by staining cleaved caspase-3 but did not affect mitosis. Our results suggest that functional mitochondria are necessary in both the proliferation and differentiation of SVZ NSCs. Furthermore, mitochondria might be involved in the mitosis and apoptosis that occur during those processes.

• Biomedical Science Letters
• /
• v.3 no.1
• /
• pp.11-20
• /
• 1997

A regulation of differentiation in human neuroblastoma cells remains poorly understood, although it is of great importance in the clinical therapy of neuroblastoma. This study was aimed to elucidate effects of DNA synthesis inhibitors on the differentiation of neuroblastoma cells on the basis of morphological, biochemical and molecular respects. Three DNA synthesis inhibitors, sodium butyrate, hydroxyurea, cytosine arabinoside were used to explore their effects on the cellular morphology, the expression of c-myc and the elevation of choline acetyltransferase activity. They led to the extension or neurite-like processes reflecting differentiation or IMR-32 cells. In addition, the treatment of three DNA synthesis inhibitors resulted in the remarkable increases in the expression of c-myc as well as the stimulation of choline acetyltransferase activity which is involved in the synthesis of acetylcholine in the differentiated cholinergic neurons. Taken together, these results indicate that DNA synthesis inhibitors play an important role in the induction of cellular differentiation in IMR-32 cells. Furthermore these DNA synthesis inhibitors seem to be future useful to give an important clue (for the treatment of neuroblastoma).

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.7 no.2
• /
• pp.52-62
• /
• 1974

The fresh water prawn, Macrobrachium rosenbergi (De Maan) is a very common species in Info-pacific region inhabiting both fresh and brackish waters in low land areas, and especially abundant in the lower reaches of most rivers which are influenced by seawater, It is one of the largest and commercial species of genus Macrobrachium. As a place of the researches to clear the possibilities of transplantation and propagation of this species in the Far East region the larval development, growth, optimum temperature and metamorphose rate up to first post larvae in aquaruim are cleared under the conditions of salinity $6.58-7.05\%_{\circ}$ Cl, pH 8.0-8.2, the rate of flow 0.3 liter per minute and illumination 3000 lux. Temperature ranged from 27.5 to $28.7^{\circ}C$ during the period of earlier larval development. For the study oil the relationship between temperature and metamorphose rate from zoea to first post larvae, the temperatures in experimental tank were $22.2^{\circ}C\pm1$, $26.1^{\circ}C\pm0.85$, $28.1^{\circ}C\pm0.34$, $30.4^{\circ}C\pm0.66$, $33.7^{\circ}C\pm0.66$, $33.7^{\circ}C\pm0.38$ and $36.8^{\circ}C\pm0.26$. During the work, food used for the larvae was Artemia salina nauplius in the filter-circulation aquariums. This species metamorphosed to the first post-larvae through eleven zoea stages, and the characters of each larval stage are described and optimum temperature for metamorphosis rate and survivals to the first post larvae is $28.1^{\circ}C\pm0.34$.

• Korean Journal of Plant Tissue Culture
• /
• v.22 no.1
• /
• pp.35-39
• /
• 1995

In order to investigate the effects of gelling agent on rice anther culture, anthers of rice (Japonica cv Daecheongbyeo) were cultured on N$_{6}$ media supplemented with 0.8, 1.2 or 1.6% Junsei agar and 05, 0.4, 0.6, 0.8 or 1.0% Gelrite (Phytagel, Sigma). On Junsei agar media, the frequency of callus induction was decreased in proportion to agar concentration. The frequency of callus induction was more increased as 67.6% and 54.8% in media containing 0.4 and 0.6% Gelrite than in agar media. The frequency of plant regeneration and spontaneous doubled-diploid was directly proportional to Junsei agar and Gelrite concentration. The number of green and spontaneous doubled diploid plant was highest on 0.6% Gelrite medium. In order to optimize the concentration of growth regulators for the callus induction medium containing 0.6% Gelrite, anthers were cultured on N$_{6}$ media supplemented with 2mg/L NAA, 2 mg/L 2,4-D, 1mg/L NAA and 1mg/L 2, 4-D, or 1mg/L NAA, 1mg/L 2,4-D and 0.5mg/L kinetin. The maximum frequency of callus induction and plant regeneration was obtained from the medium supplemented with 2 mg/L NAA and 0.6% Gelrite. In conclusion the induction of embryogenic callus, the frequency of plant regeneration and in vivo chromosome doubling was more effective in Gelrite media than in Junsei agar media.dia.

• Korean Journal of Plant Tissue Culture
• /
• v.22 no.1
• /
• pp.7-11
• /
• 1995

Protoplasts were isolated from hypocotyl tissues of 5-day-old Brassica oleracea var capitata Green Challenger seedlings. Several media were used for protoplast culture and shoot regeneration. The shoot-regeneration rapacity of protoplast derived callus depended on the initial culture medium. Protoplasts were cultured in liquid medium (B5 medium supplemented with CaCl2, 2H2O 600mg/L, g1ucose 20g/L, D-mannito1 70g/L, NAA lmg/L, BA lmg/L, 2.4-D 0.25 mg/L)at 27$^{\circ}C$ under the dark After 5 to 10 days, cultlues were diluted with medium with a reduced osmotic stabilizer and then transferred to illuminated conditions. The culture medium was changed with the fresh medium at 7- to 10-day-intervals until the formation of microcallus. Hypocotyl protoplast-derived callus proliferated when transferred to MS medium supplemented with NAA lmg/L, BA 1mg/L and GA$_3$ 0.02mg/L. Upon transfer to MS basal medium without growth regulators, roots were produced. In an attempt to increase the regeneration frequency, 10g/L polyvinylpyrrolidone was added to the regeneration medium, but the shoot regeneration was mot improved. The regenerated whole plants were acclimated in a sterized soilless mixture(vermiculite 2;perlite 2;peat moss1) in a culture room.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1993.04a
• /
• pp.162-162
• /
• 1993

제 3세대 platinum complex인 SKI 2053R에 의한 Salmonella typhimurium의 복귀변이빈도, CHL세포(Chinese Hamster Lung)에 대한 염색체이상 유발율 및 ddY계 마우스에서의 골수분화세포에 대한 염색체이상유발로 기인한 소핵의 빈도수를 관찰하여 SKI 2053R의 유전독성을 평가하였다. Salmonella typhimurium를 이용한 복귀돌연변이시험에서 SKI 2053R은 매우 경미한 정도의 돌연변이 유발성을 가지는 것으로 판단되며, 균주 특이적 돌연변이 유발성으로 보아 염기쌍치환형의 돌연변이를 유발하는 것으로 사료되며 포유류배양세포를 이용한 염색체이상실험에서 대사 활성 부재 및 존재하의 모든 시험 농도에서 10％ 이상의 염색체이상을 가진 세포가 관찰되었으며 염색체 상의 종류로는 염색분체형 교환 (cse)이 가장 많이 관찰되었다. 설치류를 이용한 소헥시험에서는 ddY계 마우스 골수세포의 분화과정에서 염색체이상을 유발하며, 다염성적혈구의 정염성적혈구에 대한 출현비율이 감소하는 결과로 볼때 방추체기능의 저해를 일으키는 것으로 판단된다. 그러므로 본 시험조건데 있어서 SKI 2053R은 소핵을 유발하는 물질로 결론지었다.