• The Korean Journal of Food And Nutrition
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• v.32 no.1
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• pp.33-40
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• 2019

The purpose of this study was to evaluate the antioxidant and hepatocyte protective effects of guava (Psidium guajava L.) leaves cultivated in Korea. The contents of the total polyphenol of the extract was 271.57 mg gallic acid equivalent (GAE)/g residue. Antioxidant activities of leaf extract were evaluated by examining the free radical scavenging ability. 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and ${\alpha}-{\alpha}$-diphenyl-${\beta}$-picrylhydrazyl (DPPH) free radical scavenging activities of the extract were 1133.23 mg trolox equivalent antioxidant capacity (TEAC)/g residue and 721.68 mg TEAC/g residue, respectively. The hepatocyte protective effect of guava leaf extract was examined in HepG2 cells. Against tert-butyl hydroperoxide (TBHP), the viability of HepG2 cells were increased by the treatment of leaf extract. In addition, guava leaf extract led to the inhibition of reactive oxygen species (ROS) generated in HepG2 cells. The leaf extract increased the activity of glutathione (GSH), glutathione reductase (GR), and glutathione peroxidase (GPx) against oxidative stress. These results suggested that guava leaves might be regarded as a potential source natural antioxidant and a hepatoprotective material.

• Journal of Biosystems Engineering
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• v.43 no.4
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• pp.394-400
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• 2018

Purpose: This research evaluated five types of nanoparticles to develop a surface-enhanced Raman spectroscopy (SERS) method for the rapid detection of two Bacillus species (Bacillus cereus and Bacillus thuringiensis) that are commonly found on fresh produce, which can cause food poisoning. Methods: Bacterial concentrations were adjusted to a constant turbidity, and a total of $30{\mu}L$ of each Bacillus cell suspension was prepared for each nanoparticle. A point-scan Raman system with laser light source of wavelength 785 nm was used to obtain SERS data. Results: There was no qualitative difference in the SERS data of B. cereus and B. thuringiensis for any of the five nanoparticles. Three gold nanoparticles, stabilized in either citrate buffer or ethanol, showed subtle differences in Raman intensities of two Bacillus species at $877.7cm^{-1}$. Conclusions: Among the three types of nanoparticles, the gold nanoparticles stabilized in citrate buffer showed the lowest standard deviation, followed by gold nanoparticles stabilized in ethanol. This result supports the potential application of gold nanoparticles for SERS-based detection of B. cereus and B. thuringiensis.

• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.591-600
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• 2018

The use of genetically modified (GM) crops has increased continuously over the world, and concerns about the potential risks of GM crops have also risen. Although, until now, GM crops have not been cultivated commercially in Korea, it is necessary to develop technology for the safe evaluation of GM crops. In this study, we investigated the influence of gene flow from GM to non-GM soybeans by the size of the pollen donor. In the experimental design, GM soybeans were placed in the center as a pollen donor and non-GM soybeans were placed in four directions as the pollen receivers. Three sizes of pollen donor were designed as $90cm{\times}90cm$, $180cm{\times}180cm$, and $360cm{\times}360cm$. A total 22,719 seeds were collected from non-GM soybeans, and 14 hybrids were finally obtained through herbicide resistance screening and PCR analysis. The highest hybridization rate was 0.78% at a distance of 15 cm from a $360cm{\times}360cm$ GM pollen donor, and the farthest distance of hybridization was 180 cm from a GM pollen donor which was $360cm{\times}360cm$ in size. Ten hybrids were found among the 14 hybrids at the $360cm{\times}360cm$ pollen donor size, 3 hybrids at $180cm{\times}180cm$, 1 hybrid at $90cm{\times}90cm$. From these results, it could be concluded that with the larger pollen donor size, more hybridization occurred in soybeans.

• Journal of Marine Bioscience and Biotechnology
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• v.11 no.1
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• pp.14-22
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• 2019

Omega-3 fatty acids and carotenoids, which are known as representative high-value substances derived from microalgae, are being studied from various diatoms. Most of the diatoms contain fucoxanthin and omega-3 fatty acid. Fucoxanthin produced by diatom has been reported as bioactive compounds exhibiting strong antioxidant, anticancer and anti-inflammatory activities. However, the low growth rate and fucoxanthin content of diatoms are one of the big obstacles to the industrial application. In this study, indigenous marine diatom Achnanthidium sp. BS-001 was isolated for a candidate of fucoxanthin producer. Light intensity and temperature for the culture of Achnanthidium sp. BS-001 were optimized on PhotoBiobox. Optimization of silicate concentration for increasing BS-001 biomass productivity was confirmed in F/2 medium with various concentration of sodium silicate. As a result, condition of light intensity, temperature, and silicate concentration for optimal cultivation were $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, $18^{\circ}C$ and 0.106 mM, respectively. Maximum biomass productivity reaches to $154.3mg{\cdot}L^{-1}{\cdot}day^{-1}$, and then the content of omega-3 fatty acids and fucoxanthin were $19.4mg{\cdot}g^{-1}$, $9.05mg{\cdot}g^{-1}$, respectively. These results indicate that Achnanthidium sp. BS-001 has the potential to be used as a source of omega-3 fatty acids and fucoxanthin.

• Parasites, Hosts and Diseases
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• v.57 no.2
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• pp.197-200
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• 2019

Cryptosporidium is a common intestinal protozoan that can lead to diarrhea in humans and dogs. The predominant species of infection are C. hominis and C. parvum in humans, and C. canis in dogs. However, C. canis can infect immunocompromised humans. Considering the close contact with humans, dogs have the potential to be reservoirs for human cryptosporidiosis. Breeding kennels are the major supply source of puppies for pet shops. The present study is to determine the molecular prevalence and characteristics of Cryptosporidium spp. found in breeding kennel dogs. A total of 314 fecal samples were collected from young and adult dogs kept in 5 breeding kennels. A polymerase chain reaction targeting the small subunit rRNA gene was employed for the detection of Cryptosporidium spp. To determine the species, the DNA sequences were compared to GenBank data. Overall, 21.0% of the fecal samples were positive for Cryptosporidium spp. infection. Cryptosporidium spp. was detected in all 5 facilities. A sequencing analysis demonstrated that all isolates shared 99-100% similarity with C. canis. The results suggest that Cryptosporidium spp. infection is present at a high-level in breeding kennel dogs. However, because dominant species in this survey was C. canis, the importance of breeding kennel dogs as reservoirs for Cryptosporidium spp. transmission to humans is likely to be low in Japan.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.290-296
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• 2019

Lithium-ion batteries are one of the most interesting devices in a number of energy storage systems. In particular, the usage of energy storage devices is increasing due to an increase in demand for renewable energy as a distributed power supply source, stable supply of electric power, and expansion of electric vehicles. Of late, the recycling and restoration technology of waste lithium ion batteries due to the increase in its usage amount as the energy storage system is a socially and economically important research field. In this review, we intend to describe the performance diagnosis, recycling or restoration technology of lithium ion battery and its potential development.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.176-189
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• 2019

This paper presents a feasibility study for producing the medical isotope $^{99m}Tc$ using the hazardous and currently wasted radioisotope $^{99}Tc$. This can be achieved with the nuclear resonance fluorescence (NRF) phenomenon, which has recently been made applicable due to high-intensity laser Compton scattering (LCS) photons. In this work, 21 NRF energy states of $^{99}Tc$ have been identified as potential contributors to the photo-production of $^{99m}Tc$ and their NRF cross-sections are evaluated by using the single particle estimate model and the ENSDF data library. The evaluated cross sections are scaled using known measurement data for improved accuracy. The maximum LCS photon energy is adjusted in a way to cover all the significant excited states that may contribute to $^{99m}Tc$ generation. An energy recovery LINAC system is considered as the LCS photon source and the LCS gamma spectrum is optimized by adjusting the electron energy to maximize $^{99m}Tc$ photo-production. The NRF reaction rate for $^{99m}Tc$ is first optimized without considering the photon attenuations such as photo-atomic interactions and self-shielding due to the NRF resonance itself. The change in energy spectrum and intensity due to the photo-atomic reactions has been quantified using the MCNP6 code and then the NRF self-shielding effect was considered to obtain the spectrums that include all the attenuation factors. Simulations show that when a $^{99}Tc$ target is irradiated at an intensity of the order $10^{17}{\gamma}/s$ for 30 h, 2.01 Ci of $^{99m}Tc$ can be produced.

• Fisheries and Aquatic Sciences
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• v.22 no.2
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• pp.6.1-6.10
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• 2019

Background: This study is aimed at identifying the anti-inflammatory properties of 70% ethanol extract produced from an edible brown seaweed Sargassum horneri (SJB-SHE) with industrial-scale production by Seojin Biotech Co. Ltd. S. horneri is a rich source of nutrient and abundantly growing along the shores of Jeju, South Korea. Methods: Here, we investigated the effect of SJB-SHE on LPS-activated RAW 264.7 macrophages. The cytotoxicity and NO production of SJB-SHE were evaluated using MTT and Griess assays, respectively. Additionally, protein expression and gene expression levels were quantified using ELISA, Western blots, and RT-qPCR. Results: Our results indicated that pre-treatment of RAW 264.7 macrophages with SJB-SHE significantly inhibited LPS-induced NO and $PGE_2$ production. SJB-SHE downregulated the proteins and genes expression of LPS-induced iNOS and COX2. Additionally, SJB-SHE downregulated LPS-induced production of pro-inflammatory cytokines (tumor necrosis factor-${\alpha}$, interleukin (IL)-6, and IL-$1{\beta}$). Furthermore, SJB-SHE inhibited nuclear factor kappa-B (NF-${\kappa}B$) activation and translocation to the nucleus. SJB-SHE also suppressed the phosphorylation of mitogen-activated protein kinases (ERK1/2 and JNK). Conclusions: Collectively, our results demonstrated that SJB-SHE has a potential anti-inflammatory property to use as a functional food ingredient in the future.

• Clinical and Experimental Otorhinolaryngology
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• v.11 no.4
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• pp.224-232
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• 2018

Objectives. Spiral ganglion neurons (SGNs) include potential endogenous progenitor populations for the regeneration of the peripheral auditory system. However, whether these populations are present in adult mice is largely unknown. We examined the presence and characteristics of SGN-neural stem cells (NSCs) in mice as a function of age. Methods. The expression of Nestin and Ki67 was examined in sequentially dissected cochlear modiolar tissues from mice of different ages (from postnatal day to 24 weeks) and the sphere-forming populations from the SGNs were isolated and differentiated into different cell types. Results. There were significant decreases in Nestin and Ki67 double-positive mitotic progenitor cells in vivo with increasing mouse age. The SGNs formed spheres exhibiting self-renewing activity and multipotent capacity, which were seen in NSCs and were capable of differentiating into neuron and glial cell types. The SGN spheres derived from mice at an early age (postnatal day or 2 weeks) contained more mitotic stem cells than those from mice at a late age. Conclusion. Our findings showed the presence of self-renewing and proliferative subtypes of SGN-NSCs which might serve as a promising source for the regeneration of auditory neurons even in adult mice.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.337-345
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• 2021

Lipase (triacylglycerol lipase, EC 3.1.1.3) is an enzyme capable of hydrolyzing triacylglycerol, to produce fatty acids and glycerol and reverse the reaction of triacylglycerol synthesis from fatty acids and glycerol through transesterification. Applications of lipase are quite widespread in the industrial sector, including in the detergent, paper, dairy, and food industries, as well as for biodiesel synthesis. Lipases by yeasts have attracted industrial attention because of their fast production times and high stability. In a previous study, a lipase-producing yeast isolate was identified as Zygosaccharomyces mellis SG1.2 and had a productivity of 24.56 U/mg of biomass. This productivity value has the potential to be a new source of lipase, besides Yarrowia lypolitica which has been known as a lipase producer with a productivity of 0.758 U/mg. Lipase production by Z. mellis SG1.2 needs to be increased by optimizing the production medium. The aims of this study were to determine the significant component of the medium for lipase production and methods to increase lipase production using the optimum medium. The two methods used for the statistical optimization of production medium were Taguchi and RSM (Response Surface Methodology). The data obtained were analyzed using Minitab 18 and SPSS 23 software. The most significant factors which affected lipase productivity were olive oil and peptones. The optimum medium composition consisted of 1.02% olive oil, 2.19% peptone, 0.05% MgSO₄·7H₂O, 0.05% KCl, and 0.2% K₂HPO₄. The optimum medium was able to increase the lipase productivity of Z. mellis SG1.2 to 1.8-fold times the productivity before optimization.