• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.411-417
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• 1998

The role of phospholipase ($A_2\;PLA_2$) in tumor cell growth was investigated using SK-N-MC human neuroblastoma cells. 4-Bromophenacyl bromide (BPB) and mepacrine (Mep), known $PLA_2$ inhibitors, suppressed growth of the tumor cells in a dose-dependent manner without a significant cytotoxicity. Melittin (Mel), a $PLA_2$ activator, enhanced the cell growth in a concentration-dependent fashion. The growth-enhancing effects of Mel were significantly reversed by the co-treatment with $PLA_2$ inhibitors. In addition, Mel induced intracellular $Ca^{2+}$ release from internal stores like as did serum, a known intracellular $Ca^{2+}$ agonist in the tumor cells. Intracellular $Ca^{2+}$ release induced by these agonists was significantly blocked by $PLA_2$ inhibitors at growth-inhibitory concentrations. Arachidonic acid (AA), a product of the $PLA_2-catalyzed$ reaction, induced cell growth enhancement and intracellular $Ca^{2+}$ release. These effects of AA were significantly blocked by BAPTA/AM, an intracellular $Ca^{2+}$ chelator. Taken together, these results suggest that the modulation of $PLA_2$ activity may be one of the regulatory mechanisms of cell growth in human neuroblastoma cells. Intracellular $Ca^{2+}$ may act as a key mediator in the $PLA_2-induced$ growth regulation.

• Membrane and Water Treatment
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• v.6 no.3
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• pp.225-235
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• 2015

During low-pressure membrane treatments of cyanobacterial cells, including microfiltration (MF) and ultrafiltration (UF), there have reportedly been releases of intracellular compounds including cyanotoxins and compounds with an earthy-musty odor into the water, probably owing to cyanobacterial cell breakage retained on the membrane. However, to our knowledge, no information was reported regarding the effect of growth phase of cyanobacterial cells on the release of the intracellular compounds. In the present study, we used a geosmin-producing cyanobacterium, Anabaena smithii, to investigate the effect of the growth phase of the cyanobacterium on the release of intracellular geosmin during laboratory-scale MF experiments with the cells in either the logarithmic growth or stationary phase. Separate detection of damaged and intact cells revealed that the extent of cell breakage on the MF membrane was almost the same for logarithmic growth and stationary phase cells. However, whereas the geosmin concentration in the MF permeate increased after 3 h of filtration with cells in the logarithmic growth phase, it did not increase during filtration with cells in the stationary phase: the trend in the geosmin concentration in the MF permeate with time was much different between the logarithmic growth and stationary phases. Adsorption of geosmin to algogenic organic matter (AOM) retained on the MF membrane and/or pore blocking with the AOM were greater when the cells were in the stationary phase versus the logarithmic growth phase, the result being a decrease in the apparent release of intracellular geosmin from the stationary phase cells. In actual drinking water treatment plants employing membrane processes, more attention should be paid to the cyanobacterial cells in logarithmic growth phase than in stationary phase from a viewpoint of preventing the leakage of intracellular earthy-musty odor compounds to finished water.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.524-530
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• 2011

In the present study, we demonstrate that SRM LC-MS/MS method developed by Luo et al. (ref. 10) can be successfully applied to the quantitative analysis of intracellular metabolites in E. coli that are collected at the exponential and stationary growth phases. A focus is given on measuring the changes in the concentrations of intracellular metabolites in batch cultures, which were induced during both the dynamically changing exponential and stationary growth phases. The following intracellular metabolites are quantified in the exponential and stationary phases of E. coli growth, using the SRM mode of a triple quadrupole mass spectrometer: glucose-1-phosphate, fructose-1,6-bisphosphate, phosphoenolpyruvate, pyruvate, acetyl-coenzyme A, 6-phosphogluconate, ribulose-5-phosphate, xylulose-5-phosphate, erythrose-4-phosphate. The determined intracellular metabolite concentration profiles are shown to be in a good agreement with the growth profiles of E. coli, which clearly indicates that SRM LC-MS/MS can be successfully used for following the metabolite changes induced at different growth stages.

• KSBB Journal
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• v.13 no.5
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• pp.585-592
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• 1998

The effect of intracellular Ca2+ level on the hybridoma cell growth and monoclonal antibody(MAb) production was examined. For the manipulation of intracellular Ca2+ concentration, the cells were treated with A23187, ryanodine, and thapsigargin at about 1x106 cells/mL. The treated cells were recultivated by using the Iscove's Modified Dulbecco's Medium(MDM) containing 1.49mM CaCl2. The ryanodine-treated cells showed better cell growth, MAb concentration, and specific MAb productivity than others. In comparison with control, the maximum cell concentration, MAb concentration, and specific MAb productivity were increased by 40.6%, 48.1% and 83.3%, respectively. Confocal microscopic images of Fura-2/AM loaded cells indicate that the increase in intracellular Ca2+ level can enhance the MAb productivity by allowing the calcium influx into the endoplasmic reticulumn.

• Korean Journal of Plant Tissue Culture
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• v.22 no.4
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• pp.183-187
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• 1995

The relationship between the intracellular phosphate level and catharanthine production in hairy root cultures of Catharanthus roseus was investigated The growth of hairy root increased in proportion to the phosphate concentration in the growth medium. When hairy roots were cultured in a phosphate-free medium, the catharanthine content was increased to the highest level As the phosphate concentration in the medium was enhanced, the catharanthine content decreased proportionally. Hairy root cultures with elevated intracellular phosphate concentrations indicated that growth was proportional to the level of intracellular phosphate. Catharanthine production increased abruptly below an intracellular phosphate level of $100\;\mumoles/g$ dry wt. The intracellular phosphate level may play a key role in the regulation of growth and secondary metabolite production.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.1
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• pp.44-47
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• 2000

Cell growth and DNA synthesis were studied from a cultured early- and late- pas- sage mouse aorta smooth muscle cell (MASMC) because the proliferation of vascular smooth muscle cell (VSMC) is a key factor in development of atherosclerosis. In this study, the cells were cultured in fetal bovine serum (FBS) and stimulated by growth factors such as thrombin and platelet-derived growth factor-BB (PDGF-BB). Compared to the number of early-passage MASMC (passage 3 to 9) the number of late-passage MASMC (passage 30 to 40) in a normal serum state was increased 2 fold at Day 1, 3 and 6 in culture, respectively. Incorporation of $[^3H]$ thymidine into DNA induced by serum, PDGF and thrombin in late-passage MASMC was greater than those in early-passage MASMC. We also examined whether intracellular zinc levels would be an aging factor or not. The intracellular zinc level in early- and late-passage MASMC was monitored by using the zinc probe dye N-(6-methoxy-8-quinolyl)-p-toluenesulfonamide. It is interested that late-passage MASMC increased the intracellular fluorescence level of zinc, more than the early passage MASMC did. The alterations of intracellular zinc level occur concurrently with changes in MASMC proliferation rate during aging. This data suggest that the age-associated changes in zinc concentrations may provide a new in vitro model for the study of smooth muscle cell differentiation.

• BMB Reports
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• v.32 no.2
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• pp.173-180
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• 1999

The effects of agmatine on the enzymes responsible for the biosynthesis of polyamines, the resultant levels of polyamines, and their effect on the growth of DU145 human prostate tumor cells were investigated. When agmatine was added to the medium, ornithine decarboxylase (ODC, EC 4.1.1.17) activity was substantially reduced, but S-adenosylmethionine decarboxylase (SAMDC, EC 4.1.1.50) activity increased markedly. These changes in ODC and SAMDC activities were the result of an induction of ODC-antizyme and a decreased turnover rate of SAMDC in the presence of agmatine. Accordingly, there was a decrease in the intracellular levels of putrescine and spermidine but an increase in the intracellular level of spermine. Cell growth was markedly inhibited by agmatine treatment and this inhibition was not recovered by the addition of putrescine or spermidine. Our results suggest that agmatine alters the intracellular amounts of polyamine in the cells, closely related to the inhibition of cell growth.

• Korean Journal of Microbiology
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• v.38 no.3
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• pp.168-172
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• 2002

Budding yeasts maintain an effective system to regulate intracellular pH in response to environmental pH fluctuation. In a previous study we reported that SHC1 plays a role in cell growth at alkaline condition, not at acid pH. We constructed a null mutant deleted an entire open reading frame for SHC1. To test whether the retardation in cell growth was caused by the absence of intracellular pH buffering capacity, we measured intracellular pH with a pH-sensitive fluorescent dye, C.SNARE. The intracellular pH of the mutant cell was much higher than that of wild-type cells, indicating that the mutant cells lack some types of buffering capacity. We also investigated the level of $Na^＋ and K^＋$ content with atomic mass spectroscopy after alkali shock. Wild-type cell showed a higher level of intracellular K^＋$ content, whereas there was no difference in $Na^＋$ level. The result suggested that K^＋$ is more important in the regulation of intracellular pH in yeasts.

• Biomolecules & Therapeutics
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• v.16 no.1
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• pp.21-27
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• 2008

Clotrimazole (CLT), a potent antifungal drug, is known to inhibit tumor cell proliferation. In the present study, we examined the role of intracellular $Ca^{2+}$ in CLT-induced cell cycle arrest of colon adenocarcinoma HT29 cells. CLT inhibited growth of HT29 cells in a concentration-dependent manner, which was associated with inhibition of cell cycle progression at the G(1)-S phase transition and an increase in the expression of cell cycle inhibitor proteins p27 and p53. CLT also suppressed the $Ca^{2+}$ overload by A23187, a calcium ionophore, suggesting its role in modulation of intracellular $Ca^{2+}$ concentration in HT29 cells. The simultaneous application of CLT and A23187 with addition of $CaCl_2$ (1mM) to the medium significantly reversed CLT-induced p27 and p53 protein level increase and growth suppression. Our results suggest that CLT induces cell cycle arrest of colon adenocarcinoma HT29 cells via induction of p27 and p53, which may, at least in part, be mediated by alteration of intracellular $Ca^{2+}$ level.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.122-126
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• 1996

Growth patterns of Saccharomyces cerevisiae NS 2031 and its total RNA contents were observed by a fed-batch fermentation with different media-feeding methods. With an exponential feeding pattern, both final cell concentrations and intracellular RNA contents decreased with increasing feeding rates. Intracellular RNA contents also decreased with the growth time. At the same feeding rate of the exponential pattern, final cell concentrations decreased with the increase of total sugar concentration whereas intracellular RNA contents increased. The highest cellular yield was 0.47 at the total sugar concentration of 10%. With increasing feeding rates of the parabolic feeding pattern, final cell concentrations decreased whereas intracellular RNA contents increased, showing a different tendency from the exponential feeding pattern. In comparison of two feeding methods, the exponential feeding pattern was better than the parabolic feeding pattern in terms of cell growth, cellular yields and intracellular RNA contents of Saccharomyces cerevisiae NS 2031. Also, the intracellular RNA contents of the exponential feeding pattern was found to be about 2% higher than that of the parabolic feeding pattern at the same instantaneous growth rate $({\mu}_{inst})$.