• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1039-1046
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• 2005

The salt resistance of antibacterial activity and synergistic effect with clinically used antibiotic agents are critical factors in developing effective peptide antibiotic drugs. For this reason, we investigated the resistance of antibacterial activity to antagonism induced by NaCl and $MgCl_2$ and the synergistic effect of P20 with cefotaxime. P20 is a 20-residue synthetic peptide derived from a cecropin A (CA)-melittin(ME) hybrid peptide. In this study, P20 was found to have potent antibacterial activity against clinically isolated methicillin-resistant Staphylococcus aureus (MRSA) strains without hemolytic activity against human erythrocytes. The combination study revealed that P20 in combination with cefotaxime showed synergistic antibacterial activity in an energy-dependent manner. We also confirmed the synergism between P20 and cefotaxime by fluorescence-activated flow cytometric analysis by staining bacterial cells with propidium iodide (PI) and bis-(1,3-dibutylbarbituric acid) trimethine oxonol (BOX). This study suggests that P20 may be useful as a therapeutic antibiotic peptide with synergistic effect in combination with conventional antibiotic agents.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.12-12
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• 2001

To get insight into the nature of foreign mitochondria and syngamy during mammalian fertilization we compared fertilization processes in porcine oocytes following microinjection of porcine or mouse spermatozoa. Pronuclear movement, sperm mitochondria, and DNA synthesis were imaged with propidium iodide, mitotracker, and BrdU under confocal laser scanning microscope. Intracytoplasmic injection of either porcine or mouse spermatzoon activated porcine oocytes without additional parthengenetic stimulation. Foreign mitochondria in either mouse or porcine sperm midpiece were introduced into porcine oocytes following sperm injection, but rapidly disappeared from the actively developing porcine oocytes. BrdU experiment showed new DNA synthesis in porcine oocytes following injection of mouse spermatozoon or sperm head. At 24 h after injection of mouse isolated sperm head or a spermatozoon, mitoic metaphase was seen in oocyte, but they did not go to normal cell division (Table). These results suggest that pronuclear formation, foreign mitochondria disruption, DNA synthesis and syngamy formation during fertilization are not species specific processes.(Table Omitted).

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.37-37
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• 2001

포유동물의 정자형성과정 (spermatogenesis) 은 유사분열과 감수분열이 동시에 일어나는 매우 복잡하지만, 효율적으로 생식세포를 증식, 분화시키는 시스템이다 정상적인 spermatogenesis가 일어나는 testis에서는 haploid (IN), diploid (2N), 그리고 tetraploid(4N)과 같은 핵형을 갖는 세포들이 일정한 비율로 존재한다. DNA flow cytometry(DNA FCM) 는 세포의 핵형(ploidy)을 신속·정확하게 측정하여, 1N, 2N 그리고 4N에 대한 비율을 예측할 수 있어서, 생식세포를 포함한 다양한 유형의 세포주기를 분석하는데 적용되어져 왔다. 세포주기 분석법 중 이와 같은 FCM이외에, flow cytometer와 static image cytometer를 결합시켜 새롭게 고안된 laser scanning cytometer (LSC)가 있다. 그리고, 이제까지 LSC를 사용한 spermatogenesis에 관한 연구에 대해서는 보고된 바가 없다. 본 실험은 설치류에 있어 각기 다른 발달단계에 있는 정상적인 정소세포를 분리하여 PI (propidium iodide) 로 DNA를 염색한 후, DNA함량을 LSC로 분석하였다. 이것을 FCM에 의한 정소세포의 DNA분석과 비교·검토하였으며, 이 방법을 정상적인 spermatogenesis 가 일어나지 않는 동물시스템에 적용시켰다. 생식세포를 소멸시키기 위해 항암제인 busulfan과 비타민 A를 결핍시켜 이것이 세포주기의 어떤 시점에서 어떻게 작용하여, 생식세포를 소멸시키는지 알아보았다. 위의 실험·분석결과로부터 LSC를 사용한 DNA함량과 핵형의 결정은 FCM과 동일한 수준의 정확성을 제시하였다. busulfan 또는 비타민 A의 결손은 살아있는 세포의 80% 이상이 2N의 핵형에 해당하는 G0/G1 기에 있는 것으로 나타났다. 그리고 1N:2N 및 4N:2N의 핵형비율의 변화를 가져왔다. 이러한 자극은 생식세포주기제어에 관여하며, 생식세포가 증폭하고 분화로 들어가는 단계를 차단, G0/G1 기에서 정체(arrest)되는 것으로 시사된다.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.3
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• pp.123-129
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• 2006

In several experimental models, estrogens protect neurons against ischemic insults. However, the recent clinical studies of hormone replacement showed negative results to prevent stroke. Therefore, optimal models to study estrogen replacement for neuroprotection are needed before its clinical ap-plication. Organotypic hippocampal slice under oxygen-glucose deprivation (OGD) has been established as a model of cerebral ischemia and has advantages to study drug effects. We investigated whether estrogen protected CAI neurons and affected activation of Akt (pAkt) in CAI region under OGD. Thus, rat hippocampal slices on day 7 of culture were treated with $17-{\beta}$ estradiol (E, 1 nM) for 7 days before 30 min OGD, and cell death of CAI neurons was quantified by propidium iodide (PI) staining and expression of pAkt was studied by Western blot and immunofluorescence. PI intensity in slices treated with E was significantly reduced 72 hour after OGD compared to that of non-treated slices (p < 0.05). E pretreatment also increased the expression of pAkt 72 hour after OGD compared to that of no treatment (p<0.01). These data suggest that estrogen pretreatment may rescue neurons from ischemic insults through the activation of Akt and also indicate that our model would be a useful alternative method to study the mechanisms and effects of estrogen replacement treatment for neuroprotection.

• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.302-306
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• 2015

VvpM, one of the extracellular metalloproteases produced by Vibrio vulnificus, induces apoptotic cell death via a pathway consisting of ERK activation, cytochrome c release, and activation of caspases-9 and -3. VvpM-treated cells also showed necrotic cell death as stained by propidium iodide (PI). The percentage of PI-stained cells was decreased by pretreatment with Necrostatin-1, indicating that VvpM-mediated cell death occurs through necroptosis. The appearance of autophagic vesicles and lipidated form of light-chain-3B in rVvpM-treated cells suggests an involvement of autophagy in this process. Therefore, the multifarious action of VvpM might be one of the factors responsible for V. vulnificus pathogenesis.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.8
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• pp.3797-3803
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• 2016

Cervical cancer is the second most common malignancy in women worldwide and thus one of the leading causes of mortality in women. Lovastatin, a non polar, anticholesterol drug has previously been reported to exert antitumour activity in vitro. In the present study, lovastatin from Aspergillus terreus (KM017963) was purified by adsoprtion chromatography and evaluated for its anticancer and anti-oxidant properties with a human cervical cancer cell line (HeLa). Growth inhibitory and proapoptotic effects of purified lovastatin on HeLa cells were investigated by determining its influence on cell numbers, mitochondrial membrane potential (MMP), DNA fragmentation and antioxidant properties in terms of hydroxy radical scavenging effects as well as levels of total reduced glutathione. Cell cycle analysis by flow cytometry (propidium iodide staining) confirmed induction of apoptotic cell death and revealed cell cycle arrest in the G0/G1 phase. Results of the study give leads for the anticancer effects of lovastatin and its potential usefulness in the chemotherapy of cervical cancer.

• Environmental Mutagens and Carcinogens
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• v.25 no.2
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• pp.76-81
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• 2005

25-Hydroxycholesterol (cholest-5-ene-3, 25-diol, 25-OHC) showed the cytotoxicity on HeLa human cervix and NCI-H460 human lung cancer cells, $0.5{\mu}M\;of\;50\%$ inhibitory concentration. We studied 25-OHC as the possibility of radiation sensitizer. The combination effect of 25-OHC and y-irradiation measured using flow cytometer with propidium iodide stained cells. The combined treatment of 25-OHC and $\gamma-irradiation$ did not show significant enhancing effects on Hela and NCI-H460 cells.

• Environmental Mutagens and Carcinogens
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• v.25 no.3
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• pp.104-109
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• 2005

[ $7{\beta}$ ]-Hydroxycholesterol (cholest-5-ene-3, 7-diol, $7{\beta}$-OHC) showed the cytotoxicity on human cervical carcinoma cells (HeLa), $10{\mu}M$ of 50% inhibitory concentration. We evaluated $7{\beta}$-OHC as the possibility of radiation sensitizer. The combination effect of $7{\beta}-OHC\;and\;{\gamma}$-irradiation was measured using colony forming assay and flow cytometer with propidium iodide and $DiOC_6$ stained cells, respectively. The combined treatment of $7{\beta}-OHC\;and\;{\gamma}$-irradiation did not show significant enhancing effects on HeLa cells.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3073-3076
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• 2012

Terpinen-4-ol is a terpene found in the rhizome of Plai (Zingiber montanum (Koenig) Link ex Dietr.). In this study apoptogenic activity and mechanisms of cell death induced by terpinen-4-ol were investigated in the human leukemic MOLT-4 cell line. Terpinen-4-ol exhibited cytotoxicity in MOLT-4 cells, with characteristic morphological features of apoptosis by Wright's staining. The mode of cell death was confirmed to be apoptosis by flow cytometric analysis after staining with annexin V-FITC and propidium iodide. A sub-G1 peak in DNA histograms of cell cycle assays was observed. Terpinen-4-ol induced-MOLT-4 cell apoptosis mediated through an intrinsic pathway involving the loss of mitochondrial transmembrane potential (MTP) and release of cytochrome c into the cytosol. In addition, terpinen-4-ol also induced apoptosis via an extrinsic pathway by caspase-8 activation resulting in the cleavage of cytosolic Bid. Truncated-Bid (tBid) translocated to mitochondria and activated the mitochondrial pathway in conjunction with down-regulation of Bcl-2 protein expression. Caspase-3 activity also increased. In conclusion, terpinen-4-ol can induce human leukemic MOLT-4 cell apoptosis via both intrinsic and extrinsic pathways.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.1977-1981
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• 2012

Houttuynia cordata Thunb (HCT) is a native herb found in Southeast Asia which features various pharmacological activities against allergy, inflammation, viral and bacterial infection, and cancer. The aims of this study were to determine the cytotoxic effect of 6 fractions obtained from silica gel column chromatography of alcoholic HCT extract on human leukemic Molt-4 cells and demonstrate mechanisms of cell death. Six HCT fractions were cytotoxic to human lymphoblastic leukemic Molt-4 cells in a dose-dependent manner by MTT assay, fraction 4 exerting the greatest effects. Treatment with $IC_{50}$ of HCT fraction 4 significantly induced Molt-4 apoptosis detected by annexinV-FITC/propidium iodide for externalization of phosphatidylserine to the outer layer of cell membrane. The mitochondrial transmembrane potential was reduced in HCT fraction 4-treated Molt-4 cells. Moreover, decreased expression of Bcl-xl and increased levels of Smac/Diablo, Bax and GRP78 proteins were noted on immunoblotting. In conclusion, HCT fraction 4 induces Molt-4 apoptosis cell through an endoplasmic reticulum stress pathway.