• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.649-659
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• 2017

Extremophilic microorganisms have established a diversity of molecular strategies in order to survive in extreme conditions. Biocatalysts isolated by these organisms are termed extremozymes, and possess extraordinary properties of salt allowance, thermostability, and cold adaptivity. Extremozymes are very resistant to extreme conditions owing to their great solidity, and they pose new opportunities for biocatalysis and biotransformations, as well as for the development of the economy and new line of research, through their application. Thermophilic proteins, piezophilic proteins, acidophilic proteins, and halophilic proteins have been studied during the last few years. Amylases, proteases, lipases, pullulanases, cellulases, chitinases, xylanases, pectinases, isomerases, esterases, and dehydrogenases have great potential application for biotechnology, such as in agricultural, chemical, biomedical, and biotechnological processes. The study of extremozymes and their main applications have emerged during recent years.

• CELLMED
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• v.8 no.2
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• pp.8.1-8.5
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• 2018

Nitric oxide (NO) is a small diffusible molecule which plays an important role in various physiological activities. NO is a notable molecule, functioning as a cytotoxic agent and cellular messenger. There has been considerable interest in NO production by activated macrophages because this gaseous metabolite plays a fundamental role in the cytotoxic and cytostatic effects of macrophages towards invasive micro-organisms and tumour cells. No is a bioactive free radical that has been implicated in many physiological functions, plays a critical role during inflammation and therefore constitutes a potential target for developing therapeutics for inflammatory diseases. The use of medicinal plants by the population has been an important alternative the resource in the treatment of various diseases. Its growing acceptance in the medical community has been due to the fact that several plants with biological activities have been scientifically investigated and their efficacy and safety have been proven. In this review, discussed suppressive effects of No production by traditional medicines in RAW 264.7 and THP-1 macrophages.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.4
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• pp.372-377
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• 2003

Feeding habits of juvenile Liparis tanakai collected from the eelgrass bed in Kwangyang Bay were studied. L. tanakai (2.0-6.0 cm SL) was a carnivore which consumed mainly amphipods (caprellids and gammarids) and caridean shrimps. Its diets also included a large amount of copepods, polychaetes and small fishes. Three distinct ontogenetic feeding groups were noted: (1) the individuals of 2.0-2.5 cm SL preyed heavily on copepods, (2) individuals of 2.5-4.0 cm SL fed mainly on amphipods. (3) individuals over 4.0 cm SL preyed mainly on caridean shrimps and small fishes. The dietary breadth of each size class showed relatively low value, and this means that juvenile L. tanakai depends on only few kinds of food organisms.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.506-508
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• 1986

Metabolic activity of inorganic nitrogenous compounds affects not only microbial growth but also metabolite production in fermentation technology. We have worked on the enzymes participating in ammonia assimulation of some fermentation bacteria. This paper summarizes the results on glutamine synthetase and its application in practical field. Glutamine synthetase (L-glutamate:ammonia ligase, EC. 6.3.1.2) catalyzes the formation of glutamine from glutamate and ammonia at the expense of cleavage of ATP and inorganic phosphate. The enzyme plays a dual role in nitrogen metabolism in bacteria; it is a key enzyme not only in the biosynthesis of various compounds through glutamine but also in the regulation of synthesis of some enzymes involved in the metabolism of nitrogenous compounds. The detailed works with the Eschericia coli and other enterobacterial enzymes revealed that glutamine synthetase is controlled by the following complex of mechanisms: (a) feedback inhibition by end products, (b) repression and derepression of enzyme synthesis, (c) modulation of enzyme activity in response to divalent cation and (d) covalent modification of enzyme protein by adenylylation and its cascade control. Comparative studies have also been made on the enzymes from other organisms.

• Journal of Microbiology and Biotechnology
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• v.30 no.6
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• pp.793-803
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• 2020

Adaptive laboratory evolution (ALE) is an evolutionary engineering approach in artificial conditions that improves organisms through the imitation of natural evolution. Due to the development of multi-level omics technologies in recent decades, ALE can be performed for various purposes at the laboratory level. This review delineates the basics of the experimental design of ALE based on several ALE studies of industrial microbial strains and updates current strategies combined with progressed metabolic engineering, in silico modeling and automation to maximize the evolution efficiency. Moreover, the review sheds light on the applicability of ALE as a strain development approach that complies with non-recombinant preferences in various food industries. Overall, recent progress in the utilization of ALE for strain development leading to successful industrialization is discussed.

• Microbiology and Biotechnology Letters
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• v.31 no.4
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• pp.435-438
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• 2003

Iron required by all organisms is related with diverse biological processes. Most eukaryotes need extra iron to maintain their nutrition balance. However, extra iron supplement gives many problem to solubility in the cells. To increase the bio-availability of iron in cells, yeast was applied to carry the iron with solubility. Selection of yeast mutants with enhanced iron uptake were performed by mutagenesis using the alkylation agent EMS. Eleven mutant strains with enhanced iron uptake were selected by the measurement of iron content with atomic absorption spectrometer. The iron content in mutants was 1.5- to 2.5-fold more than that in wild-type. These mutants could be served as iron-fortified nutrients for food and feed.

• Journal of Microbiology and Biotechnology
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• v.17 no.10
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• pp.1695-1699
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• 2007

Ferritin is an iron storage protein found in most living organisms as a natural assembled macromolecule. For studying the functional ability of the ferritin assembly, human H- and L-ferritins were expressed and purified from Pichia pastoris strain GS115. The recombinant H- and L-ferritins showed a globular form with transmission electron microscopy. The rate of iron uptake for H-ferritin was significantly faster than that for the L-ferritin in vitro. By gel permeation chromatography analysis, recombinant ferritins were confirmed as multimeric subunits with high molecular weight and it was indicated that assembled subunits were able to store iron in vivo.

• Journal of Applied Biological Chemistry
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• v.50 no.2
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• pp.74-77
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• 2007

Crude extracts of 69 marine organisms (27 salt marsh plants and 42 seaweeds) were screened for the inhibitory activity against the protein tyrosine phosphatase 1B (PTP1) in vitro. The most active extracts were methanol extracts from Derbesia marina (80.6% in inhibitory activity) and Symphycladia latiscula (85.6%) at the concentration of $15{\mu}g/mL$. Methanol extracts of Codium adhaerens and Hisikia fuziformis were moderately inhibitory with 71.2 and 69.1% inhibition, respectively. It was peculiar that only the extracts from seaweeds show inhibitory activity where those from salt marsh plants do not show any significant effect.

• Korean Journal of Weed Science
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• v.13 no.4
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• pp.195-202
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• 1993

The benefits of pesticides in improving the food quantity and quality requirements for an increasing world population are significant, and they can be described in agronomic, economic and social terms. The risks are assessed from the hazards which are likely to occur in practice ; the hazards are defined by the toxicity of the pesticide to non-target organisms at various exposure levels. There are ways of reducing the risks (mainly by reducing exposure in practice) and improving the benefits of pesticides ; these are known as risk management and benefit management respectively. The overall risk-benefit assessment is facilitated if each component can be expressed in financial terms, but it must be made nationally or locally on a sound technical basis against the prevailing agronomic, socio-economic and political circumstances. Paraquat is used to illustrate the risk-benefit assessment process in general terms, and the conclusion is that the benefits greatly outweigh the risks. It is important to keep the risks of pesticides in perspective with those associated with other naturally occurring chemicals in our diet and with other everyday aspects of life. In an overall context, the pesticide risk is small.

• Geomechanics and Engineering
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• v.7 no.6
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• pp.633-647
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• 2014

Biopolymers, polymers produced by living organisms, are used in various fields (e.g., medical, food, cosmetic, medicine) due to their beneficial properties. Recently, biopolymers have been used for control of soil erosion, stabilization of aggregate, and to enhance drilling. However, the inter-particle behavior of such polymers on soil behavior are poorly understood. In this study, an artificial biopolymer (${\beta}$-1,3/1,6-glucan) was used as an engineered soil additive for Korean residual soil (i.e., hwangtoh). The geotechnical behavior of the Korean residual soil, after treatment with ${\beta}$-1,3/1,6-glucan, were measured through a series of laboratory approaches and then analyzed. As the biopolymer content in soil increased, so did its compactibility, Atterberg limits, plasticity index, swelling index, and shear modulus. However, the treatment had no effect on the compressional stiffness of the residual soil, and the polymer induced bio-clogging of the soil's pore spaces while resulting in a decrease in hydraulic conductivity.