• Biotechnology and Bioprocess Engineering:BBE
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• 제8권6호
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• pp.322-330
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• 2003

The unicellular green alga Haematococcus pluvialis has recently attracted great inter-est due to its large amounts of ketocarotenoid astaxanthin, 3,3'-dihydroxy-${\beta}$,${\beta}$-carotene-4,4'-dione, widely used commercially as a source of pigment for aquaculture. In the life cycle of H. pluvialis, astaxanthin biosynthesis is associated with a remarkable morphological change from green motile vegetative cells into red immotile cyst cells as the resting stage. In recent years we have studied this morphological process from two aspects: defining conditions governing astaxanthin biosynthesis and questioning the possible function of astaxanthin in protecting algal cells against environmental stress. Astaxanthin accumulation in cysts was induced by a variety of environmental conditions of oxidative stress caused by reactive oxygen species, intense light, drought, high salinity, and high temperature. In the adaptation to stress, abscisic acid induced by reactive oxygen species, would function as a hormone in algal morphogenesis from veget ative to cyst cells. Furthermore, measurements of both in vitro and in vivo antioxidative activities of astaxanthin clearly demonstrated that tolerance to excessive reactive oxygen species is greater in astaxanthin-rich cysts than in astaxanthin-poor cysts or astaxanthin-less vegetative cells. Therefore, reactive oxygen species are involved in the regulation of both algal morph O-genesis and carotenogenesis, and the accumulated astaxanthin in cysts can function as a protective agent against oxidative stress damage. In this study, the physiological roles of astaxanthin in stress response and cell protection are reviewed.

• Asian-Australasian Journal of Animal Sciences
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• 제19권11호
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• pp.1580-1587
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• 2006

Several researchers have demonstrated that the rumen microbial community rapidly adapts to saponins and proposed interval feeding to prevent this rapid adaptation. An in vivo experiment was carried out to examine the effect of daily versus application every third day (interval feeding) of Sapindus rarak saponins (SE) on rumen fermentation end products, protozoal counts and nutrient digestibility. Thirty sheep were allocated into 5 groups. Sheep were fed daily or every third day with two levels of SE (0.48 and 0.72 g/kg body mass). One group received no saponin and served as control. All sheep received the same diet, a mixture of elephant grass and wheat pollard (65:35 w/w). Independent of the feeding regime and the level of inclusion, the addition of SE decreased protozoal counts and rumen ammonia concentrations (p<0.01). Microbial N supply and N retention were not affected by the high feeding regime. Daily feeding negatively influenced rumen xylanase and cellulase activity, but only when the high level of saponins was fed. However, these negative effects on rumen cell wall degradation were not reflected in decreasing total tract digestibility of the organic matter or the plant cell walls. Our results show that rumen microorganisms do not rapidly adapt to S. rarak saponins.

• Journal of Power Electronics
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• 제17권2호
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• pp.398-410
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• 2017

This work presents the design of a dual extended Kalman filter (EKF) as a state/parameter estimator suitable for adaptive state-of-charge (SoC) estimation of an automotive lithium-iron-phosphate ($LiFePO_4$) cell. The design of both estimators is based on an experimentally identified, lumped-parameter equivalent battery electrical circuit model. In the proposed estimation scheme, the parameter estimator has been used to adapt the SoC EKF-based estimator, which may be sensitive to nonlinear map errors of battery parameters. A suitable weighting scheme has also been proposed to achieve a smooth transition between the parameter estimator-based adaptation and internal model within the SoC estimator. The effectiveness of the proposed SoC and parameter estimators, as well as the combined dual estimator, has been verified through computer simulations on the developed battery model subject to New European Driving Cycle (NEDC) related operating regimes.

• BMB Reports
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• 제47권5호
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• pp.249-255
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• 2014

Polo-like kinase-1 (Plk1) belongs to a family of serine-threonine kinases and plays a critical role in mitotic progression. Plk1 involves in the initiation of mitosis, centrosome maturation, bipolar spindle formation, and cytokinesis, well-reported as traditional functions of Plk1. In this review, we discuss the role of Plk1 during DNA damage response beyond the functions in mitotsis. When DNA is damaged in cells under various stress conditions, the checkpoint mechanism is activated to allow cells to have enough time for repair. When damage is repaired, cells progress continuously their division, which is called checkpoint recovery. If damage is too severe to repair, cells undergo apoptotic pathway. If damage is not completely repaired, cells undergo a process called checkpoint adaptation, and resume cell division cycle with damaged DNA. Plk1 targets and regulates many key factors in the process of damage response, and we deal with these subjects in this review.

• Journal of Microbiology and Biotechnology
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• 제21권11호
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• pp.1184-1192
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• 2011

A bacterial isolate (strain JS-2) characterized as Bacillus sp. was challenged with high concentrations of toxic selenite ions. The microbe was found to transform the toxic, soluble, colorless selenite (${SeO_3}^{2-}$) oxyions to nontoxic, insoluble, red elemental selenium ($Se^0$). This process of biotransformation was accompanied by cytoplasmic and surface accumulation of electron dense selenium ($Se^0$) granules, as revealed in electron micrographs. The cells grown in the presence of selenite oxyions secreted large quantities of extracellular polymeric substances (EPS). There were quantitative and qualitative differences in the cell wall fatty acids of the culture grown in the presence of selenite ions. The relative percentage of total saturated fatty acid and cyclic fatty acid increased significantly, whereas the amount of total unsaturated fatty acids decreased when the cells were exposed to selenite stress. All these physiological adaptive responses evidently indicate a potentially important role of cell wall fatty acids and extracellular polymeric substances in determining bacterial adaptation towards selenite-induced toxicity, which thereby explains the remarkable competitiveness and ability of this microbe to survive the environmental stress.

• Journal of Microbiology and Biotechnology
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• 제29권8호
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• pp.1184-1192
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• 2019

The influenza A virus is a highly infectious respiratory pathogen that sickens many people with respiratory disease annually. To prevent outbreaks of this viral infection, an understanding of the characteristics of virus-host interaction and development of an anti-viral agent is urgently needed. The influenza A virus can infect mammalian species including humans, pigs, horses and seals. Furthermore, this virus can switch hosts and form a novel lineage. This so-called zoonotic infection provides an opportunity for virus adaptation to the new host and leads to pandemics. Most influenza A viruses express proteins that antagonize the antiviral defense of the host cell. The non-structural protein 1 (NS1) of the influenza A virus is the most important viral regulatory factor controlling cellular processes to modulate host cell gene expression and double-stranded RNA (dsRNA)-mediated antiviral response. This review focuses on the influenza A virus NS1 protein and outlines current issues including the life cycle of the influenza A virus, structural characterization of the influenza A virus NS1, interaction between NS1 and host immune response factor, and design of inhibitors resistant to the influenza A virus.

• Molecules and Cells
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• 제46권7호
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• pp.399-413
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• 2023

cAMP responsive element-binding protein (CREB) is one of the most intensively studied phosphorylation-dependent transcription factors that provide evolutionarily conserved mechanisms of differential gene expression in vertebrates and invertebrates. Many cellular protein kinases that function downstream of distinct cell surface receptors are responsible for the activation of CREB. Upon functional dimerization of the activated CREB to cis-acting cAMP responsive elements within the promoters of target genes, it facilitates signal-dependent gene expression. From the discovery of CREB, which is ubiquitously expressed, it has been proven to be involved in a variety of cellular processes that include cell proliferation, adaptation, survival, differentiation, and physiology, through the control of target gene expression. In this review, we highlight the essential roles of CREB proteins in the nervous system, the immune system, cancer development, hepatic physiology, and cardiovascular function and further discuss a wide range of CREB-associated diseases and molecular mechanisms underlying the pathogenesis of these diseases.

• 식물조직배양학회지
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• 제24권6호
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• pp.361-367
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• 1997

담배(Nicotiana tabacum cv. BY4)의 이배체식물과 담배의 약으로부터 유도된 반수체식물의 잎절편을 사용하여 2.4-D를 단독톄처리하여 캘러스를 유도하였다. 캘러스증식은 이배체에서는 2.0 mg/L 2.4-D와 1.0mg/L 카이네틴의 조합처리구에서, 반수체의 경우에 있어서는 2.0mg/L 2.4-D와 0.1mg/L BAP 조합처리구에서 실시하였으며, 현탁배양도 동일조건으로 실시하였다. 현탁배양 세포괴를 배양 15-20일째가 되면 0.8% low melting agarose와 혼합하여 카드a뮴이 0-2,000 $\mu$M의 농도로 처리된 선발배지에 평판배양하여 카드뮴저항성 colony(cell clump)를 조사관찰하였다. 그 결과 본 실험에서는 이배체는 세포의 성장에 있어서 최하저해농도(MIC : Minimum Inhibition Concentration)는 Cd$^{++}$ 300 $\mu$M이었으며 반수체는 Cd$^{++}$ 200 $\mu$M이었다. 이때 반수체 및 이배체의 MIC에서 선발된 세포주를 카드뮴 500, 1,000, 2,000 $\mu$M 농도로 옳겨 경화시킨 후 카드뮴저항성을 선발하였고 그 특성을 조사하였다. 그 결과 카드뮴 저항성을 띤 반수체 및 이배체유래 캘러스의 경우에는 각각 카드a뮴의 농도가 증가할수록 생중량은 감소하였으나, 건조중량은 오히려 증가하였다. 그리고 각각 선발된 세포주내의 카드뮴의 함량을 AAS를 사용하여 측정하였던 바, 카드뮴의 농도가 높을수록 캘러스에 축적된 카드뮴의 양이 높게 나타났다.

• 대한치과보철학회지
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• 제22권1호
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• pp.23-32
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• 1984

The effects between preexisting four types and one that author had designed of posterior palatal seal on the retention of denture base were compared and observed from six systemically healthy edentulous subjects. Using one without posterior palatal seal as the control, the retention of each type was measured and analyzed six times with cantilever type Load cell after adaptation of denture base, which were constructed with usual manner. The following results wear obtained. 1. Morphological and positional changes of posterior palatal seal effected on denture retention. 2. No specific type showed most desirable effect in every experimental subject. 3. Experimental subject I, II, VI showed higher retention on the control in every type. 4. In five types of posterior palatal seal, for subject III, VI F types and for subject II, V C types were most effective. 5. In each experimental subject F type showed higher retention than the control.

• The Journal of Korean Physical Therapy
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• 제15권2호
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• pp.100-110
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• 2003

The purpose of this article is to understand of the muscle adaptation based on myosin heavy chain. Especially, skeletal muscle dadptation in related to aging, unloading, training will discussed. MHC expression is highly plastic in muscles of adult mammals in accordance with the environmental conditions. These changes is called muscle plasticity. The plasticity is the atility of muscle cell to alter either the quantity of protein or the type of protein. MHC is both an important structural and regulatory protein comprising the contractile apparatus.