• Clinical and Experimental Pediatrics
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• v.54 no.6
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• pp.241-245
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• 2011

Tuberous sclerosis complex (TSC) is a genetic multisystem disorder that results from mutations in the TSC1 or TSC2 genes, and is associated with hamartomas in several organs, including subependymal giant cell tumors. The neurological manifestations of TSC are particularly challenging and include infantile spasms, intractable epilepsy, cognitive disabilities, and autism. The TSC1- and TSC2-encoded proteins modulate cell function via the mammalian target of rapamycin (mTOR) signaling cascade, and are key factors in the regulation of cell growth and proliferation. The mTOR pathway provides an intersection for an intricate network of protein cascades that respond to cellular nutrition, energy levels, and growth factor stimulation. In the brain, TSC1 and TSC2 have been implicated in cell body size, dendritic arborization, axonal outgrowth and targeting, neuronal migration, cortical lamination, and spine formation. The mTOR pathway represents a logical candidate for drug targeting, because mTOR regulates multiple cellular functions that may contribute to epileptogenesis, including protein synthesis, cell growth and proliferation, and synaptic plasticity. Antagonism of the mTOR pathway with rapamycin and related compounds may provide new therapeutic options for TSC patients.

• Journal of Microbiology and Biotechnology
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• v.20 no.12
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• pp.1677-1680
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• 2010

The harmful effects of succinic acid and oxidative stress on cell growth were determined during batch fermentation with Mannheimia succiniciproducens LPK7, a powerful succinic acid-producing strain, and conditions were optimized to minimize these effects. In terms of toxicity, the cell concentration decreased as the concentration of succinic acid increased. By changing the pH from 6.5 to 7 during fermentation, the cell concentration increased by about 10%, and the level of succinic acid production was 6% higher than that of the control. In addition, by introducing protectants, the cell concentration increased by about 10%, and the level of succinic acid produced was increased by 3%.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.1
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• pp.1-9
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• 2008

Recently, various researches have been studied on the predict method of land change according to its development. The Cellular Automata(CA) is one of the most popular methods in the urban growth modeling. The basis principle of CA is to repeat operations, which convert the current cell into new cell state by the transaction rule. It will minimize the loss of data by using Fuzzy-AHP and it can lead the flexible urban growth modeling. However, AHP would have a disadvantage to repeat the procedure of the collecting intentions until it derives the weight. Also, it is necessary for the simulation of CA to repeat the operations and the test of data accuracy should be accompanied. The purpose of this study is to predict the Busan city growth model and analyze it according to the automated test method by applying CA as well as Fuzzy-AHP. This study shall improve the difficulties caused by complexity and repetitiveness in the urban grow modeling. The practical modeling could be derived from the verification, and the derived modules could be applied to the similar case studies.

• BMB Reports
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• v.30 no.2
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• pp.119-124
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• 1997

Transforming growth $factor-{\beta}\;(TGF-{\beta})$ is a multifunctional polypeptide that exerts biological roles including cell proliferation, differentiation, extracellular matrix deposition and apoptosis in many different cell types. $TGF-{\beta}$, although known as a negative growth regulator, has not been tested in human embryo lung (HEll cells. This study attempts to understand the role of $TGF-{\beta}$ on growth control of HEL cells in relationship to tyrosine phosphorylation pattern of cellular proteins. In density-arrested HEL cells treated with $TGF-{\beta}$, analysis of Western immunoblot showed induction of tyrosine phosphorylation of two major cellular proteins (15 kDa and 45 kDa). In normal proliferating HEL cells with different concentrations of serum, further analysis indicated that the increase in tyrosine phosphorylation of a 45 kDa protein was regulated in serum concentration-dependent manner. However, in proliferating HEL cells treated with $TGF-{\beta}$, tyrosine phosphorylation of 45 kDa was down-regulated. Calcium involvement in the regulation of tyrosine phosphorylation of 45 kDa and 15 kDa proteins was also examined. Tyrosine phosphorylation of 15 kDa protein but not of 45 kDa protein was regulated by exogenous calcium. The level of tyrosine phosphorylation of 15 kDa protein was low at reduced caclium concentration and high at elevated caclium concentration. $TGF-{\beta}$ reversed the pattern of tyrosine phosphorylation of 15 kDa protein. These results suggest that tyrosine phosphorylation of 45 and 15 kDa proteins in HEL cells may be controlled depending on the physiological status of the cells, i.e., low in arrested cells and high in proliferating cells. And the tyrosine phosphorylation of the two proteins appears to be down- or up-regulated by $TGF-{\beta}$.

• Molecules and Cells
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• v.28 no.1
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• pp.57-65
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• 2009

CDC48 is a member of the AAA ATPase superfamily. Yeast CDC48 and its mammalian homolog p97 are implicated in diverse cellular processes, including mitosis, membrane fusion, and ubiquitin-dependent protein degradation. However, the cellular functions of plant CDC48 proteins are largely unknown. In the present study, we performed virus-induced gene silencing (VIGS) screening and found that silencing of a gene encoding a tobacco CDC48 homolog, NgCDC48, resulted in severe abnormalities in leaf and shoot development in tobacco. Furthermore, transgenic tobacco plants (35S:anti-NgCDC48), in which the NgCDC48 gene was suppressed using the antisense RNA method, exhibited severely aberrant development of both vegetative and reproductive organs, resulting in arrested shoot and leaf growth and sterile flowers. Approximately 57-83% of 35S:anti-NgCDC48 plants failed to develop mature organs and died at early stage of development. Scanning electron microscopy showed that both adaxial and abaxial epidermal pavement cells in antisense transgenic leaves were significantly smaller and more numerous than those in wild type leaves. These results indicate that NgCDC48 is critically involved in cell growth and development of tobacco plants. An in vivo targeting experiment revealed that NgCDC48 resides in the endoplasmic reticulum (ER) in tobacco protoplasts. We consider the tantalizing possibility that CDC48-mediated degradation of an as-yet unidentified protein(s) in the ER might be a critical step for cell growth and expansion in tobacco leaves.

• YAKHAK HOEJI
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• v.41 no.4
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• pp.433-438
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• 1997

MT 51005 as a potent inhibitor of phospholipase C(PLC) was purified from the culture broth of a fungal strain No. 51005 isolated from soil. It was identified as a benzaldehyde d erivative, anguillosporal. by the physico-chemical properties and spectroscopic data. Anguillosporal showed the inhibitory activity against purified PLC with an $IC_{50}\;of\;13{\mu}g/ml$. And it also inhibited the formation of inositol phosphates($IP_t$) in platelet-derived growth factor(PDGF)-stimulated $NIH3T3{\gamma}1$ cells with an $IC_{50}\;of\;0.8{\mu}g/ml$.

• International Journal of Oral Biology
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• v.35 no.1
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• pp.1-5
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• 2010

Human fibroblasts that maintain the structural integrity of connective tissues by secreting precursors of the extracellular matrix are typically cultured with serum. However, there are potential disadvantages of the use of serum including unnatural interactions between the cells and the potential for exposure to animal pathogens. To prevent the possible influence of serum on fibroblast cultures, we devised a serum-free growth method and present in vitro data that demonstrate its suitability for growing porcine fetal fibroblasts. These cells were grown under four different culture conditions: no serum (negative control), 10% fetal bovine serum (FBS, positive control), 10% knockout serum replacement (KSR) and 20% KSR in the medium. The proliferation rates and viabilities of the cells were investigated by counting the number of cells and trypan blue staining, respectively. The 10% FBS group showed the largest increase in the total number of cells ($1.09\;{\times}\;10^5\;cells/ml$). In terms of the rate of viable cells, the results from the KSR supplementation groups (20% KSR:64.7%; 10% KSR: 80.6%) were similar to those from the 10% FBS group (68.5%). Moreover, supplementation with either 10% ($3.0\;{\times}\;10^4\;cells/ml$) or 20% KSR ($4.8\;{\times}\;10^4\;cells/ml$) produced similar cell growth rates. In conclusion, although KSR supplementation produces a lower cell proliferation rate than FBS, this growth condition is more effective for obtaining an appropriate number of viable porcine fetal fibroblasts in culture. Using KSR in fibroblast culture medium is thus a viable alternative to FBS.

• Molecules and Cells
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• v.44 no.11
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• pp.830-842
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• 2021

When perceiving microbe-associated molecular patterns (MAMPs) or plant-derived damage-associated molecular patterns (DAMPs), plants alter their root growth and development by displaying a reduction in the root length and the formation of root hairs and lateral roots. The exogenous application of a MAMP peptide, flg22, was shown to affect root growth by suppressing meristem activity. In addition to MAMPs, the DAMP peptide PEP1 suppresses root growth while also promoting root hair formation. However, the question of whether and how these elicitor peptides affect the development of the vascular system in the root has not been explored. The cellular receptors of PEP1, PEPR1 and PEPR2 are highly expressed in the root vascular system, while the receptors of flg22 (FLS2) and elf18 (EFR) are not. Consistent with the expression patterns of PEP1 receptors, we found that exogenously applied PEP1 has a strong impact on the division of stele cells, leading to a reduction of these cells. We also observed the alteration in the number and organization of cells that differentiate into xylem vessels. These PEP1-mediated developmental changes appear to be linked to the blockage of symplastic connections triggered by PEP1. PEP1 dramatically disrupts the symplastic movement of free green fluorescence protein (GFP) from phloem sieve elements to neighboring cells in the root meristem, leading to the deposition of a high level of callose between cells. Taken together, our first survey of PEP1-mediated vascular tissue development provides new insights into the PEP1 function as a regulator of cellular reprogramming in the Arabidopsis root vascular system.

• Proceedings of the Korean Nutrition Society Conference
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• 1994.05a
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• pp.40-40
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• 1994

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.4
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• pp.231-236
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• 2001

How much do we know about the biology of aging from cell culture studies Most normal somatic cells have a finite potential to divide due to a process termed cellular or replicative senescence. A growing body evidence suggests that senescence evolved to protect higher eu-karyotes, particularly mammals, from developing cancer, We now know that telomere shortening due to the biochemistry of DNA replication, induces replicative senescence in human cells. How-ever in rodent cells, replicative senescence occurs despite very long telomeres. Recent findings suggest that replicative senescence is just the tip of the iceberg of a more general process termed cellular senescence. It appears that cellular senescence is a response to potentially oncogenic in-sults, including oxidative damage. In young orgainsms, growth arrest by cell senescence sup-presses tumor development, but later in life, due to the accumulation of senescent cells which se-cret factors that can disrupt tissues during aging, cellular senescence promotes tumorigenesis. Therefore, antagonistic pleiotropy may explain, if not in whole the apparently paradoxical effects of cellular senescence, though this still remains an open question.