• 한국가시화정보학회:학술대회논문집
• /
• 2007.11a
• /
• pp.88-91
• /
• 2007

Animal cells show different behaviors in response to the mechanical properties of the substrates. We hypothesize that the rigidity of the substrates also affects the bacterial motility and controls the colony dynamics. It is found that the colony size of Escherichia colis and Bacillus subtilis grown on the agar plates is correlated with agarose gel concentrations and thus with the substrate rigidity. High- resolution microscopic imaging reveals that bacteria in single colonies form different aggregation patterns on the agar plates with varying gel concentration. We measured the apparent diffusion coefficients in the agarose gel plates made with different gel concentrations. Mathematical modeling and quantitative imaging of dye dispersion in the agar plates suggest that there is a close connection between the diffusion rate and the colony size. Nanoscale pore structures and kinetic constraints in the porous media may have an effect on bacterial colony dynamics.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.2
• /
• pp.410-415
• /
• 2007

Recent advances in sensor network technology have open up challenges for its effective routing. Routing protocol receives most of the attention because routing protocols might differ depending on the application and network architecture. In the rapidly changing environment and dynamic nature of network formation efficient routing and energy consumption are very crucial. Sensor networks differ from the traditional networks in terms of energy consumption. Thus, data-centric technologies should be used to perform routing to yield an energy-efficient dissemination. By exploiting the advantages of both ant colony optimization techniques in network routing and the ability of data centric muting to organize data for delivery, our approach will cover features for building an efficient autonomous sensor network.

• Journal of Korean Foot and Ankle Society
• /
• v.18 no.3
• /
• pp.100-107
• /
• 2014

Purpose: The purpose of this study is to evaluate the efficacy of mesenchymal stem cell (MSC) isolation by the magnetic-activated cell sorting (MACS) method in tendon tissue-derived cells compared to the colony picking method for isolation of MSCs by picking colony-forming cells. Materials and Methods: Human tendon-derived cells were isolated by enzyme digestion using normal tendon tissues from three donors. We used the magnetic kit and well-known MSC markers (CD90 or CD105) to isolate MSCs in tendon-derived cells using MACS. Cloning cylinders were used to isolate colony-forming cells having MSC characteristics in tendon-derived cells. Colony-forming unit-fibroblast (CFU-F) assay was used to evaluate the self-renewal capacity of cells isolated using the colony picking method or MACS. For comparison of differentiation potentials into osteogenic or adipogenic lineage between two groups, alizarin red S and oil red O staining were performed at 14 days after induction of differentiation in vitro. Results: Flow cytometry results showed that early passage tendon-derived cells expressed CD44 in 99.13%, CD90 in 56.51%, and CD105 in 86.19%. In the CFU-F assay, CD90+ or CD105+ cells isolated with MACS showed larger colony formation in size than cells isolated using the colony picking method. We also observed that CD90+ or CD105+ cells were constantly differentiated into both osteogenic and adipogenic lineages in cells from all donors, whereas cells isolated using the colony picking method were heterogeneous in differentiation potentials to the osteogenic and adipogenic lineages. Conclusion: CD90+ or CD105+ cells isolated using MACS showed superior MSC characteristics in the self-renewal and multi-differentiation capacities compared with cells isolated using the colony picking method.

• Journal of dental hygiene science
• /
• v.15 no.2
• /
• pp.209-219
• /
• 2015

In order to explore an effect of interaction of Streptococcus gordonii, Fusobacterium nucleatum and Porphyromonas gingivalis that are bacteria relevant to periodontal disease on its growth, the bacteria were incubated in trypticase soy hemin menadione broth at $37^{\circ}C$ $CO_2$ incubator for 7 days through anaerobic jar by single and co-culture with heat treated dead bacteria under anaerobic gas pack. In order to confirm growth level, absorbance was measured and for confirming colony structure and form, it was observed with scanning electron microscope. In order to confirm an effect on pathogenicity of P. gingivalis, real time reverse transcriptase polymerase chain reaction was implemented for expression analysis for rgpA gene that produces HRgpA which is gingipain. As a result, the following conclusion was obtained. Colony formation of S. gordonii and P. gingivalis was increased by other dead bacteria and in case of F. nucleatum, its colony formation was showed an aspect of being increased by dead bacterium of P. gingivalis but decreased by dead bacterium of S. gordonii. Therefore, it is considered that the strains being used for this study would affect interactively through bacterial cell itself as well as their interaction factor at the time of colony formation.

• 한국생물공학회:학술대회논문집
• /
• 2005.04a
• /
• pp.139-139
• /
• 2005

• Biomolecules & Therapeutics
• /
• v.30 no.2
• /
• pp.151-161
• /
• 2022

This study elucidates the anti-cancer potential of gallic acid (GA) as a promising therapeutic agent that exerts its effect by regulating the PI3K/Akt pathway. To prove our research rationale, we used diverse experimental methods such as cell viability assay, colony formation assay, tumor spheroid formation assay, cell cycle analysis, TUNEL assay, Western blot analysis, xenograft mouse model and histological analysis. Treatment with GA inhibited cell proliferation in dose-dependent manner as measured by cell viability assay at 48 h. GA and cisplatin (CDDP) also inhibited colony formation and tumor spheroid formation. In addition, GA and CDDP induced apoptosis, as determined by the distribution of early and late apoptotic cells and DNA fragmentation. Western blot analysis revealed that inhibition of the PI3K/Akt pathway induced upregulation of p53 (tumor suppressor protein), which in turn regulated cell cycle related proteins such as p21, p27, Cyclin D1 and E1, and intrinsic apoptotic proteins such as Bax, Bcl-2 and cleaved caspase-3. The anti-cancer effect of GA was further confirmed in an in vivo mouse model. Intraperitoneal injection with GA for 4 weeks in an A549-derived tumor xenograft model reduced the size of tumor mass. Injection of them downregulated the expression of proliferating cell nuclear antigen and p-Akt, but upregulated the expression of cleaved caspase-3 in tumor tissues. Taken together, these results indicated that GA hindered lung cancer progression by inducing cell cycle arrest and apoptosis, suggesting that GA would be a potential therapeutic agent against non-small cell lung cancer.

• Korean Journal of Veterinary Research
• /
• v.43 no.1
• /
• pp.49-55
• /
• 2003

This study was performed to determine the effect of Phyllostachys nigra var. henenis Strapf leaf extract on jejunal crypt survival, endogenous spleen colony formation and apoptosis in jejunal crypt cells of mice irradiated with high and low dose of gamma-radiation. Phyllostachys nigra var. henenis Strapf administration before irradiation (I.P.: 125 mg/kg of body weight, at 24 hours before irradiation) resulted in an increase of the formation of endogenous spleen colony (p<0.01). The frequency of radiation-induced apoptosis was also reduced by pretreatment of Phyllostachys nigra var. henenis Strapf (I.P.: 280 mg/kg or 28 mg/kg of body weight, at 24 hours before irradiation, p<0.01). These results indicated that Phyllostachys nigra var. henenis Strapf might be a useful radioprotector, especially since it is a relatively nontoxic natural product. Further studies are needed to characterize better the promotion nature of Phyllostachys nigra var. henenis Strapf and its components.

• Journal of Ginseng Research
• /
• v.22 no.1
• /
• pp.66-72
• /
• 1998

Studies were performed to determine the effect of Korean red ginseng (extract powder, spray-dried), it is made of choice 6-year-old raw ginseng roots, and processed by steaming and drying, on jejunal crypt survival, endogenous spleen colony formation, and apoptosis in jejunal crypt cells of irradiated mice. Jejunal crypts were protected by pretreatment of red ginseng (1 mg/head, single I.P. at 24hours before irradiation, p<0.05). Red ginseng administration before irradiation (1 mg/head, single I.P at 24hours before irradiation) resulted in an increase of the formation of endogenous spleen colony (p<0.05). The frequency of radiation-Induced apoptosis in intestinal crypt cells was also reduced by treatment of red ginseng both pretreatment (P.O.: 2 mg/ml of drinking water for 7 days, p<0.005, I.P.: 1 mg/head, single I.P. at 24 hours before irradiation, p<0.005) and post-treatment (1 mg/head, single I.P at 30 minutes after irradiation, p<0.05). These results indicated that Korean red ginseng might be a useful radio-protector, especially since it is a relatively nontoxic natural product. Further studies are needed to characterize better the promotion nature of red ginseng and its fractions.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.35 no.4
• /
• pp.117-123
• /
• 2021

Gefitinib, a first generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI), provides obvious clinical benefit in patients with EGFR-mutant non-small cell lung cancer (NSCLC). However, patients ultimately develop gefitinib resistance which mainly caused by EGFR T790M secondary mutation. In the current study, we investigated whether the root extract of Scutellaria baicalensis (SB) overcomes gefitinib resistance. Gefitinib-resistant H1975 human NSCLC cells (EGFR L858R/T790M double mutant) were treated with gefitinib and/or ethanol extract of SB (ESB) to evaluate the effect of ESB on the gefitinib sensitivity. The cell viability was measured by MTT assay and trypan blue exclusion assay. The colony-forming ability was evaluated by anchorage-dependent colony formation assay. Combined treatment with gefitinib and ESB markedly decreased the cell viability and colony formation than single treatment with gefitinib or ESB in H1975 cells. In addition, cells treated with both gefitinib and ESB exhibited a significant increase of sub-G1 DNA content which indicates apoptotic cells compared with those treated with gefitinib or ESB alone. As a molecular mechanism, combined treatment with gefitinib and ESB strongly downregulated the phosphorylation of ERK and JNK than single treatment with gefitinib or ESB. Taken together, our results demonstrate that ESB sensitizes H1975 cells to gefitinib treatment. We cautiously propose that ESB can be used in combination with gefitinib for the advanced NSCLC patients with acquired resistance to EGFR TKIs.

• Journal of Korean Neurosurgical Society
• /
• v.66 no.6
• /
• pp.642-651
• /
• 2023

Objective : Endothelial colony-forming cells (ECFCs) have been reported to play an important role in the pathogenesis of moyamoya disease (MMD). We have previously observed stagnant growth in MMD ECFCs with functional impairment of tubule formation. We aimed to verify the key regulators and related signaling pathways involved in the functional defects of MMD ECFCs. Methods : ECFCs were cultured from peripheral blood mononuclear cells of healthy volunteers (normal) and MMD patients. Low-density lipoproteins uptake, flow cytometry, high content screening, senescence-associated β-galactosidase, immunofluorescence, cell cycle, tubule formation, microarray, real-time quantitative polymerase chain reaction, small interfering RNA transfection, and western blot analyses were performed. Results : The acquisition of cells that can be cultured for a long time with the characteristics of late ECFCs was significantly lower in the MMD patients than the normal. Importantly, the MMD ECFCs showed decreased cellular proliferation with G1 cell cycle arrest and cellular senescence compared to the normal ECFCs. A pathway enrichment analysis demonstrated that the cell cycle pathway was the major enriched pathway, which is consistent with the results of the functional analysis of ECFCs. Among the genes associated with the cell cycle, cyclin-dependent kinase inhibitor 2A (CDKN2A) showed the highest expression in MMD ECFCs. Knockdown of CDKN2A in MMD ECFCs enhanced proliferation by reducing G1 cell cycle arrest and inhibiting senescence through the regulation of CDK4 and phospho retinoblastoma protein. Conclusion : Our study suggests that CDKN2A plays an important role in the growth retardation of MMD ECFCs by inducing cell cycle arrest and senescence.