• 한국언론정보학보
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• 제36권
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• pp.324-347
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• 2006

청소년과 관련된 연구들은 '청소년주의'라는 덫에 빠지는 경향이 있다. 청소년 집단을 단일한 특성을 지닌 연령 집단으로 보는 가정에 집착하기 때문이다. 그 집착은 청소년을 성인세대와 대당으로 놓는 경향으로 연장된다. 이어 세대 논쟁으로 옮겨가기도 한다. 물론 이 같은 분류 혹은 대당은 전혀 근거가 없지는 않다. 대중매체의 성장으로 인해 청소년 세대의 문화가 획일화되는 모습을 보인다는 점에서 일면 정당성을 가지기도 한다. 또한 청소년들이 학교라는 공동체를 통해 동일 정체성을 가질 가능성도 과거에 비해 높아졌다. 하지만 청소년 집단이 성인기에 진입한 후 동맹집단으로 존재하지 않고 있음에 주목해볼 필요가 있다. 청소년 집단을 세대 집단으로만 한정짓기에는 청소년을 내부로부터 구별지어주는 명백한 변인들이 존재하고 있다. 부모의 계급이나 청소년들의 성별 등에 주목하지 않고서는 청소년 집단의 내부적 차이, 그들의 '구별 짓기' 등을 설명해낼 수가 없다. 청소년주의라는 덫은 연구자가 오류를 범하게 할 뿐만 아니라 청소년을 소외시키는 신화적 효력을 내게 된다.

• 한국유기농업학회지
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• 제19권spc호
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• pp.25-29
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• 2011

This study was performed to analyze the improvement of soil physical property and soil biota characteristics through cultivation of green manure crops for a one-year period before creation of a tea plantation as follows. The study revealed that the contents of available phosphate tended to decrease after sod-culture by green manure cultivation and open-pollination, when compared to the level before cultivation. The ratio soil porosity increased by approximately 30% when Crotalaria juncea and Sorghum bicolar L. Moench were cultivated, while the soil bacteria and fungi also increased. In a research on microfauna using a pit fall trap, the population number of the microfauna was 174 of 27 species in the plot of open-pollinated sod-culture and no organic matter application, and 268 of 26 species in the plot of Sorghum bicolar L. Moench. Consequently, the culturing tool of Crotalaria juncea recorded the highest level of species diversity at 2.5, the evenness index at 3.7 and richness at 4.6, with the lowest level of a dominance index. The ecological quotient of microfauna was 0.76 in the plot of Sorghum bicolar L. Moench, and 0.63 in the plot of Crotalaria juncea.

• Journal of Periodontal and Implant Science
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• 제26권2호
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• pp.448-468
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• 1996

To maintain its functional integrity, bone is continuously remodelled by a process involving resorption by osteoeclasts and formation by osteoblasts, In order to respond to changes in the physical environment or to trauma with the relevant action, this process is strictly regulated by locally synthesized or systemic fators, Prostaglandin $E_2(PGE_2$) is perhaps one of the best studied factors, having been known to affect bone cell function for several decades.$PGE_2$ has both anabolic and catabolic activities. Excess of $PGE_2$ has been implicated in a number of pathological states associated with bone loss in a number of chronic inflammatory conditions such as periodontal disease and rheumatoid arthritis. $PGE_2$ and other arachidonic acid metabolites have been shown to be potent stimulators of osteoclastic bone resorption in organ culture. The anabolic effects of $PGE_2$ were first noticed when an increase in periosteal woven bone formation was seen after the infusion of $PGE_2$ into infants in order to prevent closure of the ductus arteriosus. The cellular basis for the catabolic actions of $PGE_2$ has been well characterized. $PGE_2$increases osteoclast recruitment in bone marrow cell cultures. Also $PGE_2$ has a direct action on osteoclast serving to inhibit activity and can also indirectly activate osteoclast via other cells in the vicinity, presumably osteoblast. The cellular mechanisms for the anabolic actions of $PGE_2$ are not nearly so well understood. The purpose of this paper was to study the effects of $PGE_2$ and dibutyl(DB)cAMP on osteoblastic clone MC3T3El cells and on the generation of osteoclasts from their precursor cells. The effect of $PGE_2$ and DBcAMP on the induction of alkaline phoaphatase(AlP) was investigated in osteoblastic clone MC3T3El cells cultured in medium containing 0.4% fetal bovine serum. $PGE_2$ and DBcAMP stimulated ALP activity and MTT assay in the cells in a dose-dependent manner at concentrations of lO-SOOng/ml. Cycloheximide, protein synthesis inhibitor, inhibited the stimulative effect of $PGE_2$ and DBcAMP on ALP activity in the cells. $PGE_2$also increased the intracellular cAMP content in a dose-dependent fashion with a maximal effect at 500ng/ml. The effect of $PGE_2$ on the generation of osteoclasts was investigated in a coculture system of mouse bone marrow cells with primary osteoblastic cells cultured in media containing 10% fetal bovine serum.After cultures, staining for tartrate-resistant acid phosphatase(TRAP)-marker enzyme of osteoclast was performed. The TRAP(+) multinucleated cells(MNCs), which have 3 or more nuclei, were counted. More TRAP(+) MNCs were formed in coculture system than in control group. $PGE_2(10^{-5}10^{-6}M)$ stimulated the formation of osteoclast cells from mouse bone marrow cells in culture. $PGE_2(10^{-6}M)$ stimulated the formation of osteoclast cells from mouse bone marrow cells in coculture of osteoblastic clone MC3T3E1 cells This results suggest that $PGE_2$ stimulates the differentiation of osteoblasts and generation of osteoclast, and are involved in bone formation, as well as in bone resorption.

• BMB Reports
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• 제48권3호
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• pp.139-146
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• 2015

Adaptive brain function and synaptic plasticity rely on dynamic regulation of local proteome. One way for the neuron to introduce new proteins to the axon terminal is to transport those from the cell body, which had long been thought as the only source of axonal proteins. Another way, which is the topic of this review, is synthesizing proteins on site by local mRNA translation. Recent evidence indicates that the axon stores a reservoir of translationally silent mRNAs and regulates their expression solely by translational control. Different stimuli to axons, such as guidance cues, growth factors, and nerve injury, promote translation of selective mRNAs, a process required for the axon's ability to respond to these cues. One of the critical questions in the field of axonal protein synthesis is how mRNA-specific local translation is regulated by extracellular cues. Here, we review current experimental techniques that can be used to answer this question. Furthermore, we discuss how new technologies can help us understand what biological processes are regulated by axonal protein synthesis in vivo.

• International Journal of Oral Biology
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• 제30권1호
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• pp.23-30
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• 2005

Bone remodeling is a process controlled by the action of two major bone cells; the bone forming osteoblast and the bone resorbing osteoclast. In the process of osteoclastogenesis, stromal cells and osteoblast produce RANKL, OPG, and M-CSF, which in turn regulate the osteoclastogenesis. During the bone resorption by activated osteoclasts, extracellular $Ca^{2+}/{PO_4}^{2-}$ concentration and degraded organic materials goes up, providing the hypertonic microenvironment. In this study, we tested the effects of hypertonicity due to the degraded organic materials on osteoclastogenesis in co-culture system. It was examined the cellular response of osteoblastic cell in terms of osteoclastogenesis by applying the sucrose, and mannitol, as a substitute of degraded organic materials to co-culture system. Apart from the sucrose, mannitol, and NaCl was tested to be compared to the effect of organic osmotic particles. The addition of sucrose and mannitol (25, 50, 100, 150, or 200 mM) to co-culture medium inhibited the number of tartrate-resistant acid phosphatase (TRAP) positive multinucleated cells induced by 10 nM $1{\alpha},25(OH)_2vitaminD_3$ ($1{\alpha},25(OH)_2D_3$). However, NaCl did exert harmful effect upon the cells in this co-culture system, which is attributed to DNA damage in high concentration of NaCl. To further investigate the mechanism by which hypertonicity inhibits $1{\alpha},25(OH)_2D_3$-induced osteoclastogenesis, the mRNA expressions of receptor activator of nuclear factor (NF)-kB ligand (RANKL) and osteoprotegerin (OPG) were monitored by RT-PCR. In the presence of sucrose (50 mM), RANKL mRNA expression was decreased in a dose-dependent manner, while the change in OPG and M-CSF mRNA were not occurred in significantly. The RANKL mRNA expression was inhibited for 48 hours in the presence of sucrose (50 mM), but such a decrement recovered after 72 hours. However, there were no considerable changes in the expression of OPG and M-CSF mRNA. Conclusively, these findings strongly suggest that hypertonic stress down-regulates $1{\alpha},25(OH)_2D_3$-induced osteoclastogenesis via RANKL signal pathway in osteoblastic cell, and may playa pivotal role as a regulator that modulates osteoclastogenesis.

• 한국미생물·생명공학회지
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• 제48권4호
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• pp.463-470
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• 2020

삼림지역의 고목에서 분리한 JS18 균주는 합성 멜라닌을 탈색하는 세포 외 분비효소를 생산했다. JS18 균주의 internal transcribed spacer (ITS) 염기서열을 분석하고 계통학적으로 확인한 결과 본 균주는 Trametes velutina로 동정되었다. JS18 균주는 laccase 활성을 나타냈지만 manganese peroxidase 및 lignin peroxidase 활성은 나타내지 않았다. 본 균주를 회분배양한 결과 멜라닌 탈색 활성은 laccase 활성으로부터 유래하는 것으로 확인되었다. Laccase 유도인자로써 Syringic acid 및 CuSO4를 첨가하고 25℃에서 7일간 배양한 결과 배양상등액에서 98 U/ml의 laccase 활성을 나타내었다. GYP 배지에서 배양한 T. velutina의 배양상등액에서 ammonium sulfate 침전, Hi-trap Q Sepharose 컬럼 및 gel filtration을 이용하여 효소를 정제하였고, SDS-PAGE에서 약 67 kDa의 분자량을 나타내었다. 정제된 효소의 멜라닌 탈색율은 효소 단독으로는 24 시간 만에 단지 4% 만을 나타내는 반면, HBT의 존재 하에서는 80%로 향상되었다. 또한 1.5 mM HBT의 농도에서는 최대 81%의 멜라닌 탈색율을 나타내었다. 본 효소의 멜라닌 탈색에 대한 최적 pH 및 온도는 각각 5.0와 37℃를 나타내었다. 본 연구에서는 T. velutina JS18 유래 laccase가 촉매하는 멜라닌 탈색 반응에서 redox mediator로써 HBT의 적용 가능성을 확인하였다.

• 동의생리병리학회지
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• 제22권4호
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• pp.891-895
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• 2008

Natural substances have recently received much attention as therapeutic drugs to prevent many diseases in humans because they avoid the many side effects of treatment with chemical compounds. We examined the effect of water extract of deer antler in RANKL-induced osteoclast differentiation. The effects of water extract of deer antler in osteoclast differentiation were determined by culture of bone marrow macrophages (BMMs). The mRNA expression levels of c-Fos, NFATc1, TRAP, and GAPDH in BMMs were analyzed by RT-PCR. Cell lysates were obtained from the treated cells, the expression levels of c-Fos and NFATc1 were determined by western blotting with antibodies for c-Fos and NFATc1. Water extract of deer antler greatly inhibited RANKL-mediated osteoclast differentiation in osteoclast precursors without cytotoxicity. Water extract of deer antler inhibited the expression of c-Fos and NFATc1 in BMMs treated with RANKL. Our findings suggest that water extract of deer antler inhibited osteoclast differentiation by suppressing c-Fos and NFATc1 expression in response to RANKL. These results demonstrate that water extract of deer antler may be a useful the treatment of bone-related disease such as osteoporosis.

• 식물조직배양학회지
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• 제27권4호
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• pp.259-268
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• 2000

Senescence is a sequence of biochemical and physiological events that lead to death of a cell, organ, or whole organism. Senescence is now clearly regarded as a genetically determined and evolutionarilly acquired developmental process comprising the final stage of development. However, in spite of the biological and practical importance, genetic mechanism of senescence has been very limited. Through forward and reverse genetic approaches, we are trying to reveal the molecular and genetic mechanism of senescence in plants, employing leaf organs of Arabidopsis as a model system. Using forward genetic approach, we have initially isolated several delayed senescence mutants either from T-DNA insertional lines or chemical-mutagenized lines. In the case of ore 4 and ore 9 mutants, the mutated genes were identified. The recent progress on characterization of mutants and identification of the mutated genes will be reported. We are also screening mutations from other various sources of mutant pools, such as activation tagging lines and promoter trap lines. Two dominant senescence-delayed mutants were isolated from the activation tagging pool. Cloning of the genes responsible for this phenotype is in progress. For reverse genetic approach, the genes that induced during leaf senescence were first isolated by differential screening method. We are currently using PCR-based suppression subtractive hybridization, designed to enrich a cDNA library for rare differentially expressed transcripts. Using this method, we have identified over 35 new sequences that are upregulated at leaf senescence stage. We are investigating the function of these novel genes by systemically generating antisense lines.

• Journal of Microbiology and Biotechnology
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• 제23권9호
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• pp.1221-1228
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• 2013

Two lipase genes (bpl1 and bpl3) from Antarctic Bacillus pumilus strains were expressed in Bacillus subtilis. Both recombinant lipases BPL1 and BPL2 were secreted to the culture medium and their activities reached 3.5 U/ml and 5.0 U/ml, respectively. Their molecular masses apparent using SDS-PAGE were 23 kDa for BPL1 and 19 kDa for BPL3. Both lipases were purified to homogeneity using ammonium sulfate precipitation and HiTrap SP FF column and Superose 12 column chromatographies. The final specific activities were estimated to be 328 U/mg for BPL1 and 310 U/mg for BPL3. Both lipases displayed an optimum temperature of $35^{\circ}C$, similar to other mesophilic enzymes. However, they maintained as much as 70% and 80% of the maximum activities at $10^{\circ}C$. Accordingly, their calculated activation energy at a temperature range of $10-35^{\circ}C$ was 5.32 kcal/mol for BPL1 and 4.26 kcal/mol for BPL3, typical of cold-adapted enzymes. The optimum pH of BPL1 and BPL3 was 8.5 and 8.0, respectively, and they were quite stable at pH 7.0-11.0, showing their strong alkaline tolerance. Both lipases had a preference toward medium chain length ($C_6-C_{10}$) fatty acid substrates. These results indicate the potential for the two Antarctic B. pumilus lipases as catalysts in bioorganic synthesis, food, and detergent industries.

• Journal of Acupuncture Research
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• 제32권3호
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• pp.27-40
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• 2015

Objectives : This study was performed to evaluate the effects of water extract of Cervi Parvum Cornu(CPC), Aconiti Lateralis Radix Preparata(ALR), and Yongbu-tang(YBT) on suppression of the receptor activator of nuclear factor kappa-B ligand(RANKL)-induced osteoclast differentiation and bone resorption. Methods : The effects of CPC, ALR, YBT extracts on osteoclast differentiation were determined by culture of bone marrow macrophage(BMM). The mRNA expression levels of the nuclear factor of activated T-cells cytoplasmic 1(NFATc1), c-Fos and tartrate-resistant acid phosphatase(TRAP) in BMMs were analyzed by reverse transcriptase polymerase chain reaction(RT-PCR). Similarly, the protein expression levels of NFATc1, c-Fos, mitogen-activated protein kinase(MAPK)s and ${\beta}$-actin in cell lysates were measured by western blotting. In addition, effects of CPC, ALR and YBT extracts were determined by means of Lipopolysaccharide(LPS)-induced bone-loss with mice. Results : CPC, ALR and YBT extracts showed remarkable inhibition on RANKL-induced osteoclast differentiation without cytotoxicity. CPC and ALR extracts significantly reduced the protein expression level of NFATc1. YBT extract significantly reduced the mRNA expression levels of c-Fos, NFATc1 and the protein expression levels of c-Fos, NFATc1, AKT, p38, c-Jun N-terminal kinase(JNK). Further, YBT extract suppressed degradation of$ I-{\kappa}B$. And ALR extract significantly restored the bone erosion by LPS treatment in mice. Conclusions : YBT extract showed more remarkable inhibition on osteoclast differentiation than CPC and ALR extracts in vitro. ALR extract showed remarkable inhibition on bone resorption in vivo. Thus, YBT extract can be a useful treatment for bone-loss diseases such as osteoporosis.