• Environmental Analysis Health and Toxicology
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• 제23권3호
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• pp.143-164
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• 2008

Concern about perfluorinated compounds (PFCs) is growing nationally as well as globally. PFCs could be considered emerging POPs due to their environmentally persistent, bioaccumulative, and potentially harmful properties. Moreover. perfluoroalkylates (PFAs) such as PFOS and PFOA are reported to experience long-range transport (LRT) to the Arctic in spite of their low volatility and strong solubility. The possible pathways contributing to LRT have been proposed but are still in debate in combination with unclear source definition and uncertain physico-chemical properties. The environmental fate of PFCs is more complicated because of the presence of precursors that are degraded to PFAs and are extremely different from their daughters, PFAs. in physico-chemical properties. To what extent and through what pathways are human and wildlife exposed is determined by the environmental fate and distribution of PFCs. To define uncertainties in fate and distribution thus is critical to prevent erroneous policy and/or determination related with exposure and risk reduction. This article aimed to review controversy and/or uncertain issues for the environmental fate and distribution of PFCs and to prospect research topics necessary to dissolve uncertainties.

• Molecules and Cells
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• 제46권12호
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• pp.727-735
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• 2023

Stem cells require high amounts of energy to replicate their genome and organelles and differentiate into numerous cell types. Therefore, metabolic stress has a major impact on stem cell fate determination, including self-renewal, quiescence, and differentiation. Lysosomes are catabolic organelles that influence stem cell function and fate by regulating the degradation of intracellular components and maintaining cellular homeostasis in response to metabolic stress. Lysosomal functions altered by metabolic stress are tightly regulated by the transcription factor EB (TFEB) and TFE3, critical regulators of lysosomal gene expression. Therefore, understanding the regulatory mechanism of TFEB-mediated lysosomal function may provide some insight into stem cell fate determination under metabolic stress. In this review, we summarize the molecular mechanism of TFEB/TFE3 in modulating stem cell lysosomal function and then elucidate the role of TFEB/TFE3-mediated transcriptional activity in the determination of stem cell fate under metabolic stress.

• 한국해양공학회지
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• 제19권4호
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• pp.35-41
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• 2005

There has been increasing offshore oil exploration, drilling, and production activities, as well as a huge amount of petroleum being transported by tankers and pipelines through the ocean and costal environment. Assessment must be made of the potential risk of damage resulting from the exploration, development and transportation activities. This is achieved through predictive impact evaluations of the fate of hypothetical or real oil spills. VVhen an oil spill occurs, planning and execution of cleanup measures also require the capability to forecast the short-term and long-term behavior of the spilled oil. A great amount of effort has been spent by government agencies, oil industries, and researchers over the past decade to develop more realistic models for oil spills. Numerous oil spill models have been developed and applied, most of which attempt to predict the oil spill fate and behavior. For an actual contingency planning, the oil fate and behavior model should be combined with an oil spill incident model, an environmental impact and risk model and a contingency planning model. The purpose of this review study is to give an overview of existing oil spill models that deal with the physical, chemical, biological, and socia-economical aspects of the incident, fate, and environmental impact of oil spills. After reviewing the existing models, future research needs are suggested. In the study, available oil spill models are separated into oil spill incident, oil spill fate and behavior, environmental impact and risk, and contingency planning models. The processes of the oil spill fate and behavior are reviewed in detail and the characteristics of existing oil spill fate and behavior models are examined and classified so that an ideal model may be identified. Finally, future research needs are discussed.

• 철학연구
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• 제130권
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• pp.1-22
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• 2014

이 글의 목적은 '안지약명(安之若命)'으로 대표되는 장자 운명관을 현실 체념적이고 노예적인 순응주의로 간주하는 이택후(李澤厚)의 입장과 해석상의 충돌을 시도하고 장자의 입장이 참된 운명 긍정론임을 밝히는 것이다. 이것은 특히 망(忘)의 역할 분석을 통해 진행된다. 그 결과 새롭게 창조되는 가치는 두 가지다. 하나는 통상적으로 인식의 결여나 질병 상태 등 부정적 기능으로 간주되어 온 망각의 긍정적 역할이며, 다른 하나는 몸 생사 세계 변화를 일기(一氣)의 운행으로 통찰함으로써 운명에 긍정적으로 대처하는 '기 통하는 인간'의 가능성이다. 이러한 논의를 위한 글의 전개는 다음과 같다. 먼저 명(命)의 용례 분석을 통해 '안지약명(安之若命)'의 의미를 밝힌다. 분석 결과 안지약명은 '인간의 힘으로 어찌할 수 없는 상황 앞에서는 마음 편히 운명을 따르라'는 의미다. 다음으로 안지약명을 노예적 순응주의로 간주하는 이택후의 입장에 반대해 장자 입장이 운명 긍정론임을 밝힌다. 이것은 장자의 운명 대면법을 네 단계로 추적함으로써 진행된다. 첫째 부득이(不得已)한 운명적 상황을 있는 그대로 직시한다. 둘째 이 때 망각을 통해서 인간적 애락(哀樂)의 고통과 물아(物我) 구분을 해소한다. 셋째, 몸 생사 세계 변화를 일기(一氣)의 운행으로 통찰한다. 넷째, 이러한 과정은 운명 앞에 긍정적으로 대처하는 기(氣) 통하는 인간을 탄생시킨다. 그는 왜 운명 앞에서 긍정적일 수 있는가? 기 통하는 인간은 사물의 이치에 통달하고 그것의 흐름에 따라서 자유자재로 변화하며, 그 결과 외계 사물로 인해 자신의 생명을 해치지 않는다. 따라서 어떤 운명적 상황 앞에서도 사태를 있는 그대로 긍정하며 담담히 포용할 수 있다. 즉 장자의 기 통하는 인간은 운명을 긍정한다. 여기서 이택후의 비판은 극복된다. 필자는 이처럼 부득이한 운명 앞에서 비관 혹은 도피나 노예적 순응이 아닌 적극적 대면과 긍정적 포용의 태도를 취하는 장자의 안지약명을 '장자의 운명애'라고 부를 수 있다고 본다. 이러한 점에도 불구하고 필자는 '기 통하는 인간'의 실제적 가능성과 역할 등에 관해서는 면밀히 논하지 못했다. 이것은 장자의 기론과 수양론을 연관시켜 분석할 때 밝혀질 수 있는 문제들이다. 이러한 점에 대해서는 차후의 지면을 통해 좀 더 구체적인 논의를 진행할 수 있기를 바란다.

• BMB Reports
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• 제49권2호
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• pp.93-98
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• 2016

Germline stem cells (GSCs) are the best understood adult stem cell types in the nematode Caenorhabditis elegans, and have provided an important model system for studying stem cells and their cell fate in vivo, in mammals. In this review, we propose a mechanism that controls GSCs and their cell fate through selective activation, repression and mobilization of the specific mRNAs. This mechanism is acutely controlled by known signal transduction pathways (e.g., Notch signaling and Ras-ERK MAPK signaling pathways) and P granule (analogous to mammalian germ granule)-associated mRNA regulators (FBF-1, FBF-2, GLD-1, GLD-2, GLD-3, RNP-8 and IFE-1). Importantly, all regulators are highly conserved in many multi-cellular animals. Therefore, GSCs from a simple animal may provide broad insight into vertebrate stem cells (e.g., hematopoietic stem cells) and their cell fate specification.

• 한국환경농학회지
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• 제12권1호
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• pp.69-80
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• 1993

Environmental hazards of a chemical could be assessed by two different approaches : toxicity test and assessment of exposure potentials to human and environmental organisms. For the prediction of environmental fate of chemicals three available computer programs were compared each other and were verified. The results obtained by using these computer programs, PCHEM, EXAMS, and E4CHEM were summarized as follows. The estimated octanol/water partition coefficients by PCHEM were similar to the experimental values in the literature. But the other factors, water solubility and vapor pressure were different from the data in the literature. The simulation results of selected compounds by EXAMS showed similar tendency to the literature results of model field environment. Therefore, this computer program could be utilized to predict the environmental fate of chemicals. E4CHEM program is very simple and this program could predict the ultimate environmental fate of stable chemicals by input of two or three parameters. However, the validity should further be verified in the future field study using more compounds. It is suggested that these approaches could be fully utilized by understanding their limitations to predict the environmental fate of new chemicals under development, to screen the potential environmental pollutants among chemicals already-in use, and to devise measures to minimize the hazards to the environment.

• Biomolecules & Therapeutics
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• 제27권1호
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• pp.15-24
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• 2019

Neural stem cells (NSCs) can proliferate and differentiate into multiple cell types that constitute the nervous system. NSCs can be derived from developing fetuses, embryonic stem cells, or induced pluripotent stem cells. NSCs provide a good platform to screen drugs for neurodegenerative diseases and also have potential applications in regenerative medicine. Natural products have long been used as compounds to develop new drugs. In this review, natural products that control NSC fate and induce their differentiation into neurons or glia are discussed. These phytochemicals enable promising advances to be made in the treatment of neurodegenerative diseases.

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2002년도 Molecular and Cellular Response to Toxic Substances
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• pp.197-197
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• 2002

• Journal of Ginseng Research
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• 제42권1호
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• pp.116-121
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• 2018

Background: Black ginseng (BG) has greatly enhanced pharmacological activities relative to white or red ginseng. However, the effect and molecular mechanism of BG on muscle growth has not yet been examined. In this study, we investigated whether BG could regulate myoblast differentiation and myotube hypertrophy. Methods: BG-treated C2C12 myoblasts were differentiated, followed by immunoblotting for myogenic regulators, immunostaining for a muscle marker, myosin heavy chain or immunoprecipitation analysis for myogenic transcription factors. Results: BG treatment of C2C12 cells resulted in the activation of Akt, thereby enhancing hetero-dimerization of MyoD and E proteins, which in turn promoted muscle-specific gene expression and myoblast differentiation. BG-treated myoblasts formed larger multinucleated myotubes with increased diameter and thickness, accompanied by enhanced Akt/mTOR/p70S6K activation. Furthermore, the BG treatment of human rhabdomyosarcoma cells restored myogenic differentiation. Conclusion: BG enhances myoblast differentiation and myotube hypertrophy by activating Akt/mTOR/p70S6k axis. Thus, our study demonstrates that BG has promising potential to treat or prevent muscle loss related to aging or other pathological conditions, such as diabetes.

• BMB Reports
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• 제46권4호
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• pp.219-224
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• 2013

The cell-fate specification of the anchor cell (AC) and a ventral uterine precursor cell (VU) in Caenorhabditis elegans is initiated by a stochastic interaction between LIN-12/Notch receptor and LAG-2/Delta ligand in two neighboring Z1.ppp and Z4.aaa cells. Both cells express lin-12 and lag-2 before specification, and a small difference in LIN-12 activity leads to the exclusive expressions of lin-12 in VU and lag-2 in the AC, through a feedback mechanism of unknown nature. Here we show that the expression pattern of lag-1/CSL, a transcriptional repressor itself that turns into an activator upon binding of the intracellular domain of Notch, overlaps with that of lin-12. Site-directed mutagenesis of LAG-1 binding sites in lag-1 maintains its expression in the AC, and eliminates it in the VU. Thus, AC/VU cell-fate specification appears to involve direct regulation of lag-1 expression by the LAG-1 protein, activating its transcription in VU cells, but repressing it in the AC.