• Bulletin of the Korean Chemical Society
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• v.7 no.2
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• pp.113-116
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• 1986

Spectral behaviors of cationic dyes, methylene blue(MB) and acridine orange(AO), with varying concentrations of sodium dodecylsulfate(SDS) were studied. At low concentration of SDS(<1mM), these dyes formed insoluble dye-surfactant aggregates. When [SDS] is 4-5 mM, the aggregates were dissolved into mixed micelles of constant composition. At higher concentration of [SDS], the composition of mixed micelles were changed with [SDS], resulting only monomeric form of dyes in micelles. AO-SDS system showed greater aggregating and less dissolving properties, and weaker effect of salt than MB-SDS system did. These were attributed to the greater hydrophobic nature of the former dye. The monomer/dimer ratios of dyes in mixed micelles at given [SDS] were greatest at $20^{\circ}C$, reflecting the dependency of CMC of the surfactant on temperature.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.6
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• pp.507-514
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• 2015

Nitric oxide (NO) is important in the regulation of bone remodeling, whereas high concentration of NO promotes cell death of osteoblast. However, it is not clear yet whether NO-induced autophagy is implicated in cell death or survival of osteoblast. The present study is aimed to examine the role of NO-induced autophagy in the MC3T3-E1 cells and their underlying molecular mechanism. The effect of sodium nitroprusside (SNP), an NO donor, on the cytotoxicity of the MC3T3-E1 cells was determined by MTT assay and expression of apoptosis or autophagy associated molecules was evaluated by western blot analysis. The morphological observation of autophagy and apoptosis by acridine orange stain and TUNEL assay were performed, respectively. Treatment of SNP decreased the cell viability of the MC3T3-E1 cells in dose- and time-dependent manner. SNP increased expression levels of p62, ATG7, Beclin-1 and LC3-II, as typical autophagic markers and augmented acidic autophagolysosomal vacuoles, detected by acridine orange staining. However, pretreatment with 3-methyladenine (3MA), the specific inhibitor for autophagy, decreased cell viability, whereas increased the cleavage of PARP and caspase-3 in the SNP-treated MC3T3-E1 cells. AMP-activated protein kinase (AMPK), a major autophagy regulatory kinase, was activated in SNP-treated MC3T3-E1 cells. In addition, pretreatment with compound C, an inhibitor of AMPK, decreased cell viability, whereas increased the number of apoptotic cells, cleaved PARP and caspase-3 levels compared to those of SNP-treated MC3T3-E1 cells. Taken together, it is speculated that NO-induced autophagy functions as a survival mechanism via AMPK activation against apoptosis in the MC3T3-E1 cells.

• Journal of Life Science
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• v.25 no.11
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• pp.1230-1234
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• 2015

GATA binding protein 6 (GATA6) is a transcription factor that is expressed in the early blastocyst stage and controls the expression of important genes in the differentiation and development of the heart, pancreas, and intestine. This study confirmed the role of GATA6 in cell differentiation and organ development using mouse embryonic stem cells and zebrafish, respectively. First, the mouse embryonic stem cells were differentiated into pacemaker cardiomyocytes. An RT-PCR analysis revealed that the expression of the GATA6 gene was greatly increased from day 4 of differentiation. The expression of GATA6 was upregulated prior to increased expression of NK2 homeobox 5 (Nkx2.5) and myocyte enhancer factor 2C (MEF2C), which are critical transcription factors involved in regulating heart formation. To examine the role of GATA6 in development, GATA6 morpholino was microinjected into zebrafish embryos. Knockdown of GATA6 expression significantly decreased the heart size and heart rate in the zebrafish compared to a control. In addition, the brains were degenerated in the GATA6 morpholino-injected zebrafish. Acridine orange staining showed that knockdown of GATA6 expression increased apoptotic cells in the brain. Interestingly, knockdown of GATA6 expression decreased apoptotic cells in the early bud stage. This study points to the importance of the GATA6 gene in heart and brain development.

• Development and Reproduction
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• v.2 no.1
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• pp.1-8
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• 1998

In mammalian ovary, major portion(>99%) of ovarian follicles undergo atresia. Recent studies have shown that this phenomenon is mediated via GC apoptosis. Ceramide, a product of sphingomyelin hydrolysis, has been proposed as a novel lipid second messenger with specific roles in mediating antiproliferative responses including apoptosis and cell cycle arrest. In the present study, we have examined the effect of ceramide on apoptotic cell death of GC in vitro. GCs were harvested by squeezing the antral follicles from the immature mice (3-4 weeks) and cultured in MEM medium with 10% fetal bovine serum. The cells were treated with various concentrations of ceramide (0 to 50 \mu M)and cultured up to 24 h.Cell death was determined by MTT cell viability assay and apoptosis was examined by acridine orange staining, in situ 3'-end labeling(TUNEL), and flow cytometry. Ceramid treatment induced apoptotic cell death of GC in a time- and a dose-dependent manner. Results of flow cytometric analysis showed that creamide-induced cell death was mostly confined to the $G_{0}$/$G_{1}$ cells. these results provide an evidence for ceramide as a lipid second messenger of apoptosis in mouse GC.

• Parasites, Hosts and Diseases
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• v.26 no.4
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• pp.229-238
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• 1988

In vitro culture of Toxoplasma gondii in HL-60 cells and cell-mediates immunity against Toxoplasma in dimethylsulfoxide(DMSO) -induced HL-60 cells, i.e., differentiation into granulocytes, were pursued. HL-60 calls were treated with various concentrations of DMSO, and 1.3%(v/v) for 3 day incubation was chosen as the optimal condition icy differentiation into granulocytes. The degree of differentiation was assayed in physiological and functional aspects in addition to morphological point. When treated with 1.3% DMSO for 3 days, HL-60 cells did not synthesiar DNA materials beyond background level, and showed active chemotactic response to chemotactic peptide, formal-methionyl-leucyl-phenylalanine(FMLP). Morphologically promyelocytes of high nuclearlcytoplasmic(NIC) ratio changed to granulocytes of relatively low WJC ratio. The relationships between HL-60 cells or DMSO-induced HL-60 cells and Toxoplasma were examined after stain with Giemsa and Buorescent dye (acridine orange). HL-60 cells did not show any sign of torso- plasmacidal activity but showed intracellular proliferation of Texoplasma to form rosette for 72 hr co-culture. In contrast, OMSO-induced HL-60 cells phagocytosed Toxoplasma within 1 hr, and performed a process of intracellular digestion of Toxoplasma thereafter. With the above results, it is suggested that phagosome-Iysosome fusion is one of the critical events for the parasitism by Toxoplasma or for susceptibility of host cells. The in vitro culture system of this study has offered a defined condition to study the protozoan parasite-host cell interactions.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.313-318
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• 2016

Bacteria in the viable but nonculturable (VBNC) state fail to produce colonies on routine bacteriological media, but are still alive in the state of very low metabolic activity. The aim of the present study was to induce the VBNC state of the Edwardsiella tarda using sea water microcosm under starvation conditions at $10^{\circ}C$ and to investigate resuscitation of the VBNC cells in temperatures changed from 10 to $25^{\circ}C$, with and without additives. E. tarda entered into the VBNC state within about 42-84 days of incubation in the microcosm. Throughout this period, the total cell counts as determined using acridine orange direct counting remained near the original inoculum level of ${\sim}10^8cells/ml$. The live cell counts measured with direct viable counting, on the other hands, declined to ${\sim}10^4cells/ml$. When the VBNC cells were incubated with addition of yeast extract, fish muscle extract or serum at $25^{\circ}C$, the ratios of resuscitated samples were 37%, 23%, and 37%, respectively. The characteristics of resuscitated E. tarda were consistent with those of the original E. tarda. When the resuscitated E. tarda were intraperitoneally injected into olive flounders, all fishes died within 5 days, indicating that the VBNC E. tarda might retain its pathogenic potential. Therefore, E. tarda under starvation conditions in the winter enter into the VBNC state and the VBNC E. tarda cells resuscitated at summer and autumn seawater temperature are considered to be pathogen continuously to olive flounder on the southern coast of Korea.

• Tuberculosis and Respiratory Diseases
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• v.69 no.2
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• pp.81-94
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• 2010

Background: Autophagy is an important adaptive mechanism in normal development and in response to changing environmental stimuli in cancer. Previous papers have reported that different types of cancer underwent autophagy to obtain amino acids as energy source of dying cells in nutrient-deprived conditions. However, whether or not autophagy in the process of lung cancer causes death or survival is controversial. Therefore in this study, we investigated whether nutrient deprivation induces autophagy in human H460 lung cancer cells. Methods: H460, lung cancer cells were incubated in RPMI 1640 medium, and the starved media, which are BME and RPMI media without serum, including 2-deoxyl-D-glucose according to time dependence. To evaluate the viability and find out the mechanism of cell death under nutrient-deprived conditions, the MTT assay and flow cytometry were done and analyzed the apoptotic and autophagic related proteins. It is also measured the development of acidic vascular organelles by acridine orange. Results: The nutrient-deprived cancer cell is relatively sensitive to cell death rather than normal nutrition. Massive cytoplasmic vacuolization was seen under nutrient-deprived conditions. Autophagic vacuoles were visible at approximately 12 h and as time ran out, vacuoles became larger and denser with the increasing number of vacuoles. In addition, the proportion of acridine orange stain-positive cells increased according to time dependence. Localization of GFP-LC3 in cytoplasm and expression of LC-3II and Beclin 1 were increased according to time dependence on nutrient-deprived cells. Conclusion: Nutrient deprivation induces cell death through autophagy in H460 lung cancer cells.

• Journal of Life Science
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• v.15 no.4 s.71
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• pp.626-632
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• 2005

The polyamines are essential components of all eukaryotic cells and absolutely necessary for cell growth. In the present study, the cytoprotective role of polyamine was characterized. When $Ac_2F$ rat liver cells were treated with 1M 2,2'-azobis (2-amidinopropane) dehydrochloride (AAPH), a water soluble free radical initiator, viability of the cells was noticeably decreased due to the increase of reactive oxygen species (ROS). The cytotoxic effect of AAPH as well as ROS generation were significantly inhibited by the treatment of polyamines. Among polyamines, especially spermine at $20{\mu}M$ concentration exerted over $45\%$ inhibition of AAPH-induced ROS generation. Western blotting was performed to determine whether superoxide dismutase(SOD) or catalase (CAT) expression was involved in oxidative stress. The AAPH treatment blocked both SOD and CAT protein expressions. Spermine could recover those protein expressions to the untreated control levels. According to the result of cycline E measurement, AAPH might block the entry of the cells into S phase of the cell cycle. The reduced expression of cyclin E protein could be fully recovered by the addition of spermine. The antioxidative effects of spermine was also further proved by the apopotitic morphological analysis using ethidium bromide and acridine orange.

• Journal of the korean veterinary medical association
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• v.18 no.4
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• pp.52-61
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• 1982

This paper describes the results obtained from the study carried out on the diagnosis of toxoplasmosis in Korea. 1. The outbreak of toxoplasmosis in Korea was first reported in swine in 1957. 2. For postmortem diagnosis of toxoplasmosis, animal inoculatio

• Journal of Microbiology
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• v.45 no.2
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• pp.171-174
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• 2007

The growth stimulation of wild plants by several bacterial species showing plant growth-promoting capabilities was examined in a barren lakeside area at Lake Paro, Korea. Microbial numbers and activities in the field soil were monitored for 73 days after inoculation of the bacteria. The acridine orange direct counts for the total soil bacterial populations ranged between $2.0-2.3{\times}10^{9}\;cells/g$ soil and $1.4-1.8{\times}10^{9}\;cells/g$ soil in the inoculated and uninoculated soils, respectively. The numbers of Pseudomonas spp., which is known as a typical plant growth-promoting rhizobacteria, and the total microbial activity were higher in the inoculated soil compared to those in the uninoculated soil. The average shoot and root lengths of the wild plants grown in the inoculated soil were 17.3 cm and 12.4 cm, respectively, and longer than those of 11.4 cm and 8.5 cm in the uninoculated soil. The total dry weight of the harvested wild plants was also higher in the inoculated soil (42.0 g) compared to the uninoculated soil (35.1 g). The plant growth-promoting capabilities of the inoculated bacteria may be used for the rapid revegetation of barren or disturbed land, and as biofertilizer in agriculture.