• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.297-301
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• 2004

The dTDP-D-glucose 4,6-dehydratase from Salmonella enterica was immobilized using covalent binding to cyanogen bromide activated sepharose. The immobilized enzyme was used to produce dTDP-4-keto-6-deoxy-D-glucose, a key sugar intermediate that can be used economically to produce diverse classes of unusual sugars appended in various antibiotics. The enzyme was immobilized on the sepharose after activation with cyanogen bromide. The maximum immobilization (80.03％) was achieved after 14 h of coupling. The covalently immobilized enzyme was stable, and an average of 78.4 ％ conversion was achieved until 120 h of immobilization when it was repeatedly used. Similar conversion was noticed for the first batch using the enzyme entrapped-hydrogel but activity was gradually decreased in the following batches. The production of dTDP-4-keto-6-deoxy-D-glucose by using an immobilized enzyme has high potential for commercial application.

• Journal of Microbiology and Biotechnology
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• v.5 no.6
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• pp.364-369
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• 1995

Effect of two-phase culture on Mentha piperita cell growth and essential oil formation was investigated using shake flask and air-lift bioreactors. LiChroprep RP-B(RP-B) addition did not impair M. piperita cell growth, but resulted in stimulated formation of essential oils and increased ratios of extracellular oil to intracellular oil formation. However, the combined use of RP-B and chitosan elicitor was not synergistic. Volumetric productivity of essential oils in RP-B treated culture using cell-recycled air-lift bioreactor was $6.9\;\mu\textrm{g}/l{\cdot}day$ which was substantially higher than that obtainable from the control. Our results demonstrate the potential of a second phase to enhance overall productivity for M. piperita cell culture.

• Research in Plant Disease
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• v.24 no.2
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• pp.99-112
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• 2018

Certain agrochemicals may be tuned for increased effectiveness when downsized to nanoparticles (NPs), where one dimension is less than 100 nm. The NPs may function as fertilizers, pesticides and products to improve plant health through seed priming, growth promotion, and induction of systemic tolerance to stress. Formulations will allow targeted applications with timed release, reducing waste and pollution when compared to treatments with bulk-size products. The NPs may be a single component, such as nano-ZnO as a fertilizer, or be composites of compatible materials, for example where N, P, and K plus micronutrients are available. The active materials could be loaded into porous carriers or tethered to base nanostructures. Coatings could include such natural products alginate, chitosan, zein, or silica. Certain NPs are taken up and transported in the plant's phloem and xylem so systemic effects are feasible. Timed and targeted release of the active product could be achieved in response to changes in pH or availability of ligands within the plant or the rhizosphere. Global research has revealed the many potentials offered by NP formulations to aid sustainability in agriculture. Current work will provide information needed by regulatory agencies to assess their safety in the agricultural setting.

• Journal of Marine Bioscience and Biotechnology
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• v.6 no.1
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• pp.17-25
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• 2014

Periodically, harmful algal blooms (HABs) have occurred, with impacts on various areas including public health, tourism, and aquatic ecosystems, especially aquacultured and caged fisheries. To prevent or manage invasions of HABs into fish farms on an emergency basis, many methods have been proposed. Frequently over the past 30 years in coastal countries, treatments of clay and clay mixed with polyaluminum chloride (PAC) and chitosan have been tested for HAB-removal effectiveness in both the laboratory and the field. In Korea, yellow loess clay (hwangto) has been dispersed using electrolytic clay dispensers, both to decrease the amount of yellow loess clay's usage in containers and enhance HAB-removal efficiency. However, this emergency method has limitations, among which is the requirement for more effective controlling agents for field applications. Thus, in this paper, we review technologies for clay-based red tides prevention and control and their limitations, and, further, introduce next-generation algicidal technologies for the emergency protection of fish farms.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3259-3264
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• 2010

A label-free amperometric immunosensor has been proposed for the detection of myeloperoxidase (MPO) in human serum. To fabricate such an immunosensor, a composite film consisting of N,N-dimethylformamide (DMF), multiwall carbon nanotubes (MWCNTs) and 1-ethyl-3-methyl imidazolium tetrafluoroborate ($EMIMBF_4$) suspension was initially formed on a glassy carbon electrode (GCE). Then cerium dioxide ($CeO_2$) dispersed by chitosan was coated on the GCE. After that, MPO antibodies (anti-MPO) were attached onto the nano$CeO_2$ surface. With a noncompetitive immunoassay format, the antibody-antigen complex formed between the immobilized anti-MPO and MPO in sample solution. The immunosensor was characterized by cyclic voltammetry, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The factors influencing the performance of the immunosensor were studied in detail. Under optimal conditions, the current change before and after the immunoreaction was proportional to MPO concentration in the range of 5 to $300\;ng\;mL^{-1}$ with a detection limit of $0.2\;ng\;mL^{-1}$.

• Food Science of Animal Resources
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• v.33 no.2
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• pp.229-238
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• 2013

Lactic acid bacteria (LAB) are added to different food products for a long time due to health beneficial effects on human host. LAB is applied in dairy products, such as yoghurt, cheese, and various fermented products, and also in non-dairy products, such as sausages. However, reaching the human gut alive as well as in a sufficient cell amount to exert positive health effects is still a big challenge, due to LAB sensitive character and vulnerability against harsh and detrimental conditions in human digestive system. Keeping physiological activity of sensitive LAB strains alive is for the formulation of novel food products with a probiotic health claim of utmost interest, thus microencapsulation has been applied and investigated as a promising technique for a good and reliable protection. Microencapsulation allows reduced cell injury or cell loss by retaining cells within the encapsulating membrane and can be enforced by spray-drying, emulsion, extrusion, and a range of other technologies in combination with an appropriate coating material, such as alginate, chitosan, and mixture of these two polymers. In this review, established and well-studied microencapsulation techniques with their favored coating materials, as well as the recent applications of microencapsulated LAB into dairy products will be discussed.

• Applied Biological Chemistry
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• v.45 no.3
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• pp.129-133
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• 2002

Suppression of nitrate accumulation in spinach and lettuce through foliar application of chitosan formula containing micronutrients is related with the increase of the nitrate reductase (NR) activity. If NR in spinach were highly expressed to increase the assimilatory activity, nitrate content could be reduced. For this, NR cDNA was cloned from the isolated mRNAs of spinach using reverse transcriptase-PCR. Nucleotide sequence of cloned spinach NR cDNA showed highly deduced amino acid sequence identity ($71{\sim}82%$) with other known plant NR genes. Only two nucleotide-base differences were observed in the cloned NR cDNA compared with that of the published spinach NR cDNA.

• Journal of Microbiology and Biotechnology
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• v.24 no.1
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• pp.80-86
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• 2014

Tannase (Tan410) from a soil metagenomic library was immobilized on different supports, including mesoporous silica SBA-15, chitosan, calcium alginate, and amberlite IRC 50. Entrapment in calcium alginate beads was comparatively found to be the best method and was further characterized. The optimum pH of the immobilized Tan410 was shifted toward neutrality compared with the free enzyme (from pH 6.4 to pH 7.0). The optimum temperature was determined to be $45^{\circ}C$ for the immobilized enzyme and $30^{\circ}C$ for the free enzyme, respectively. The immobilized enzyme had no loss of activity after 10 cycles, and retained more than 90% of its original activity after storage for 30 days. After immobilization, the enzyme activity was only slightly affected by $Hg^{2+}$, which completely inhibited the activity of the free enzyme. The immobilized tannase was used to remove 80% of tannins from a green tea infusion on the first treatment. The beads were used for six successive runs resulting in overall hydrolysis of 56% of the tannins.

• Journal of the Korean Dietetic Association
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• v.10 no.1
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• pp.58-64
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• 2004

This study was performed to investigate the kinds of health food advertised and sold through media like printed matter, TV broadcasting or internet. It was found that fifty three percent of the health food was circulated through internet, 27% through printed matter, 9% through TV Broadcasting. When the health foods was classified, the proportion of special purpose nutritious foods was 36.1%, health aid foods 33.9%, uncooked powdered foods 18.5%, functional foods for health 4.9%, Ginseng products 3.9%, and tea 0.9%. The special purpose nutritious foods was composed of 59% of nutrition supplementary foods, 24% of dietary fiber foods, 9% of weaning foods, 7% of milk formula and 2% of HCA. Vegetable extracts occupied 21.1% of health aid foods, yeast 7.5%, mushroom extracts 7.0%, chitosan 6.2%, aloe 5.3%. Dried powdered type health food occupied the highest proportion. The other type were capsule(18.8%), tablet(18.1%), and liquid type(16.4%). When the health food was classified with health claim, the proportion of "nutrition supplementation" was the highest (23.9%), "diet" 14.9%, "ergogenic"(18.8%), "promoting bowel movement" 7.8%, "growth" 5.7%, "regulation of blood sugar" 4.5%, "improving of immunity"(2.4%) and anti-aging effect(2.4%).

• Journal of Life Science
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• v.16 no.7 s.80
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• pp.1087-1089
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• 2006

Shrimp has efficient non-specific defense mechanisms based on activities of the hemocytes against pathogens. Up to now, it has been known that one of the non-specific immune reactions is related to mutual association among types of hemocyte, granular cell, semi-granular cell, and hyaline cell. In this study, we tried to know the effectiveness of feed-additives such as 5-aminolevulinic acid(ALA), chitosan, and hot-water extract of herb on immunity of shrimp (Penaeus chinensis) by hemocytic observation and SDS-PAGE analysis. Finally, we suggest a principle of the examination system for effects of various feed-additives.