• Macromolecular Research
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• v.16 no.1
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• pp.15-20
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• 2008

The enhanced permeability and retention (EPR) effect is used extensively for the passive targeting of many macromolecular drugs for tumors. Indeed, the EPR concept has been a gold standard in polymeric anticancer drug delivery systems. This study investigated the tumoral distribution of self-assembled nanoparticles based on the EPR effect using fluorescein and radio-labeled nanoparticles. Self-assembled nanoparticles were prepared from amphiphilic chitosan derivatives, and their tissue distribution was examined in tumor-bearing mice. The size of the nanoparticles was controlled to be 330 run, which is a size suited for opening between the defective endothelial cells in tumors. The long-circulating polymer nanoparticles were allowed to gradually accumulate in the tumors for 11 days. The amount of nanoparticles accumulated in the tumors was remarkably augmented from 3.4%ID/g tissue at 1 day to 25.9%ID/g tissue at 11 days after i.v. administration. The self-assembled nanoparticles were sustained at a high level throughout the 14 day experimental period, indicating their long systemic retention in the blood circulation. The ${\gamma}$-images provided clear evidence of selective tumor localization of the $^{131}I$-labeled nanoparticles. Confocal microscopy revealed the fluorescein-labeled nanoparticles to be preferentially localized in the perivascular regions, suggesting their extravasation to the tumors through the hyperpermeable angiogenic tumor vasculature. This highly selective tumoral accumulation of nanoparticles was attributed to the leakiness of the blood vessels in the tumors and their long residence time in the blood circulation.

• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1392-1398
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• 2006

We investigated a possible coordination between the biosyntheses of two polyketides in the cereal head blight fungus Gibberella zeae, zearalenone (ZEA) and aurofusarin (AUR), which are catalyzed by the polyketide synthases (PKS) PKS4/PKS13 and PKS12, respectively. To determine if the production of one polyketide influences that of the other, we used four different transgenic strains of G zeae; three were deficient for either ZEA or AUR or both, and one was an AUR-overproducing strain. The mycelia of both the wild-type and ${\Delta}PKS4$ strain deficient for ZEA produced AUR normally, whereas the mycelia of both the ${\Delta}PKS12$ and ${\Delta}PKS4::{\Delta}PKS12$ strain showed no AUR accumulation. All the examined deletion strains caused necrotic spots on the surface of com kernels and were found to produce the nonpolyketide mycotoxins trichothecenes to the same amount as the wild-type strain. In contrast, the AUR-deficient ${\Delta}PKS12$ strains produced greater quantities of ZEA and its derivatives than the wild-type progenitor on both a rice substrate and a liquid medium; the AUR-overproducing strain did not produce ZEA on either medium. Furthermore, the expression of both PKS4 and PKS13 was induced earlier in the ${\Delta}PKS12$ strains than in the wild-type strain, and there was no difference in the transcription of PKS12 between the two strains. Therefore, these results indicate that the ZEA biosynthetic pathway is negatively regulated by the accumulation of another polyketide (AUR) in G zeae.

• Journal of Ecology and Environment
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• v.30 no.3
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• pp.271-276
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• 2007

A simple and efficient protocol was developed for culturing Cu-tolerant and Cu-accumulating plants via pre-adaptation to Cu during plant tissue culture. We induced multiple shoots from begonia (Begonia evansiana Andr.) leaf explants on MS medium supplemented with naphtaieneacetic acid and benzyladenine. After 3 months, small plantlets were transferred to MS medium supplemented with $100{\mu}M\;CuCl_2$ for pre-adaptation to Cu and cultured for 5 months. Then, these plantlets were individually planted in pots containing artificial soil. An additional 500 mg of Cu dissolved in 1/4 strength MS solution was applied to each pot during irrigation over the course of 2 months. We planted pre-adapted and control begonias in soil from the II-Kwang Mine, an abandoned Cu mine in Pusan, Korea, to examine their ability to tolerate and accumulate Cu for phytore-mediation. Pre-adapted begonias accumulated $1,200{\mu}g$ Cu/g dry root tissue over the course of 45 days. On the other hand, non-Cu-adapted controls accumulated only $85{\mu}g$ Cu/g dry root tissue. To enhance Cu extraction, chelating agents, ethylenediamine tetraacetic acid (EDTA)-dipotassiun and pyridine-2,6-dicarboxylic acid (PDA), were applied. While the chelating agents did not enhance accumulation of Cu in the roots of control begonias, EDTA application increased the level of Cu in the roots of pre-adapted begonias twofold (to $2,500{\mu}g$ Cu/g dry root tissue). Because pre-adapted begonias accumulated a large amount of Cu, mainly in their roots, they could be used for phytostabilization of Cu-contaminated soils. In addition, as a flowering plant, begonias can be used to create aesthetically pleasing remediation sites.

• Journal of Periodontal and Implant Science
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• v.28 no.2
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• pp.377-388
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• 1998

This double-blind controlled clinical and microbiological study was carried out to determine the effects of mouthwash preparation containing the mixture of herbal extract on developing plaque and gingivitis in the experimental gingivitis model. Following a 2-week normalization period, 34 dental students were distributed randomly into 1 of 3 treatment groups. They rinsed, under supervision, two times daily for 3 weeks with either normal saline(CT), 0.1% chlorhexidine(CH), or the mixture of herbal extract (HT), but refrained from any oral hygiene measures. The Plaque Index(PlI), the Gingival Index(GI), and the amount of Gingival Crevicular Fluid(GCF) were measured at week 0,1,2, and 3 of the experimental period, while the assessment of total wet weight of plaque and the phase contrast microscopic examination of plaque were performed at the end of experimental period(3 weeks). Subjects using mouthrinse preparation containing the mixture of herbal extract demonstrated negligible, if any, changes in the accumulation and microbial composition of plaque compared to those using normal saline, while the reduction of gingival inflammation by this mixture was highly significant and comparable to that of chlorhexidine. The results of this study indicate that the preparation containing the mixture of herbal extract do not provide any antiplaque benefits but is very effective in inhibiting the development of and in reducing existing experimental gingivitis when used as mouthrinse. Further research is needed to determine whether a significant reduction of gingival inflammation without a concomitant decrease in plaque accumulation is of clinical importance.

• Korean journal of applied entomology
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• v.21 no.4 s.53
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• pp.222-226
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• 1982

Changes in levels of phenolic compounds such as total phenols, flavonols and anthocyanins in Macrophoma-infected apples were studied at various developmental stages of apple fruits. The amounts of total phenols in apple fruit flesh and peel drastically decreased as apples became mature. Apple rot resulted in concentration of total phenols somewhat lower than those of healthy apple flesh. The decline in amount of total phenols was distinct in infected fruit flesh of the cultivar Fuji, which was more susceptible to Macrophoma sp. than the cultivar Miller. Higher amounts of total phenols were found in infected than in heathy fruit peel. In the case of the cultivar Miller, increased accumulation of total phenols was pronounced in infected peel. Apple rot resulted in concentrations of flavonols much higher than those of healthy apples. In particular, the drastically increased accumulation of flavonols was detected in infected peel at the first collection on 10 July, when the cultivars tested were completely resistant to Macrophoma sp. Production of anthocyanins was increased considerably by apple rot: anthocyanins in infected fruits of the cultivar Miller increased markedly as compared with their concentration from healthy fruits. These results suggest that the altered phenolic metabolism in apple fruits may be associated with the development of apple rot.

• Mycobiology
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• v.35 no.3
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• pp.129-134
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• 2007

Systemic effect of two plant growth-promoting rhizobacterial (PGPR) strains, viz., Pseudomonas fluorescens (Pf4) and P. aeruginosa (Pag), was evaluated on pea (Pisum sativum) against the powdery mildew pathogen Erysiphe pisi. Foliar spray of the two PGPR strains was done on specific nodal leaves of pea and conidial germination of E. pisi was observed on other nodal leaves, distal to the treated ones. Conidial germination was reduced on distant leaves and at the same time, specific as well as total phenolic compounds increased in the leaves distal to those applied with PGPR strains, thereby indicating a positive correlation. The strains induced accumulation of phenolic compounds in pea leaves and the amount increased when such leaves were get inoculated with E. pisi conidia. Between the two strains, Pag was found to be more effective than Pf4 as its effect was more persistent in pea leaves. Foliar application of PGPR strains for the control of powdery mildew of pea is demonstrated in vitro while correlating it with the increased accumulation of plant phenolics.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.4
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• pp.357-365
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• 2020

The aim of present study was to investigate regulatory mechanism of alpha-linolenic acid (ALA) during in vitro maturation (IVM) on nuclear and cytoplasmic maturation of porcine oocytes. Basically, immature cumulus-oocyte complexes (COCs) were incubated for 22 h in IVM-I to which hormone was added, and then further incubated for 22 h in IVM-II without hormone. As a result, relative cumulus expansion was increased at 22 h after IVM and it was enhanced by treatment of ALA compared with control group (p < 0.05). During IVM process within 22 h, cAMP level in oocytes was decreased at 6 h (p < 0.05) and it was recovered at 12 h in ALA-treated group, while oocytes in control group recovered cAMP level at 22 h. In cumulus cells, it was reduced in all time point (p < 0.05) and ALA did not affect. Treatment of ALA enhanced metaphase-I (MI) and MII population of oocytes compared with oocytes in control group at 22 and 44 h, respectively (p < 0.05). Intracellular GSH levels in ALA group was increased at 22 and 44 h after IVM (p < 0.05), whereas it was increased in control group at 44 h after IVM (p < 0.05). In particular, the GSH in ALA-treated oocytes during 22 h of IVM was higher than control group at 22 h (p < 0.05). Lipid amount in oocytes from ALA group was higher than control group (p < 0.05). Treatment of ALA did not influence to absorption of glucose from medium. Cleavage and blastocyst formation of ALA-treated oocytes were enhanced compared with control group (p < 0.05). These findings suggest that supplementation of ALA could improve oocyte maturation and development competence through increasing GSH synthesis, lipid storage, and regulation of cAMP accumulation during early 22 h of IVM, and these might be mediated by cumulus expansion.

• The Southeast Asian review
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• v.28 no.4
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• pp.1-29
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• 2018

The purpose of this study is to review the Southeast Asian studies in Korea in a comprehensive way and to set a new task for our academic community. To do this, I tried to analyze the total amount and trends of scholarly achievement (thesis, journal articles, and academic books). The content is divided into research history, research accumulation, and researcher scale. The history of research dates back more than we thought and was decentralized. Research accumulation is becoming more and more pluralistic. The number of researchers from various academic fields was higher than expected. The newly discovered Southeast Asian studies of Korea suggests the task of increasing the inclusiveness of our academic community. The KASEAS (Korean Association of Southeast Asian Studies) seems to be narrow and stagnant compared to the trend of Southeast Asian studies in Korea, which is constantly growing quantitatively, academically spreading, and transcending nationality. In order to increase the inclusiveness of the KASEAS, efforts should be made to open a variety of decentralized and autonomous study groups, to invite domestic graduate students from Southeast Asia, and to spread the university's foothold as a point of contact between pluralistic disciplines.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.3
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• pp.197-204
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• 2021

In MBR, extracellular polymeric substance (EPS) is known as an important factor of fouling; soluble EPS (sEPS) affects internal contamination of membrane, and bound EPS (bEPS) affects the formation of the cake layer. The production of EPS changes according to the composition of influent, which affects fouling characteristics. Therefore, in this study, the effects of the F/M ratio on the sEPS concentration, bEPS content, and fouling were evaluated. The effects of F/M ratio on the amount and composition of EPS were confirmed by setting conditions that were very low or higher than the general F/M ratio of MBR, and the fouling occurrence characteristics were evaluated by filtration resistance distribution. As a result, it was found that the sEPS increased significantly with the increase of the F/M ratio. When the substrate was depleted, bEPS content decreased because bEPS was hydrolyzed into BAP and seemed to be used as a substrate. In contrast, when the substrate is sufficient, UAP (utilization-associated products) was rapidly generated in proportion with the consumption of the substrate. UAP has a relatively higher Protein/Carbohydrate ratio (P/C ratio) than BAP, and this means, it has a higher adhesive force to the membrane surface. As a result, UAP seems like causing fouling rather than BAP (biomass-associated products). Therefore, R_f (Resistance of internal contamination) increased rapidly with the increase of UAP, and R_c (Resistance of cake layer) increased with the accumulation of bEPS in proportion, and as a result, the fouling interval was shortened. According to this study, a high F/M ratio leads to an increment in UAP generation and accumulation of bEPS, and by these UAP and bEPS, membrane fouling is promoted.

• Journal of Mushroom
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• v.3 no.2
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• pp.79-84
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• 2005

The research for incubation period, mycelial density, day required for primordial formation after inoculation(below DPI), number of valid stipes, individual weight and accumulation amounts of organic selenium for P. cornucopiae by treating 100, 200, 300, 400, 500(${\mu}g/50g$) of $Na_2SeO_3$ is following. Incubation periods of P. cornucopiae are 20~23 days per each low concentration treatment with $Na_2SeO_3$. Compared to the control which took 22 days of incubation period, it is reduced 1 or 2 days. Mycelial density of P. cornucopiae treated with $Na_2SeO_3$ between 100 and $500{\mu}g/50g$ is very compact. DPI of P. cornucopiae treated with $Na_2SeO_3$ between 100 and $400{\mu}g/50g$ was reduced 1 or 2days, but $500{\mu}g/50g$ was increased 1 day. Number of valid stipes of P. cornucopiae treated with $Na_2SeO_3$ between 100 and $400{\mu}g/50g$ is between 19 and 20. It was increased 1 or 2, as compared to 18 of control, but $500{\mu}g/50g$ was reduced to 1. Individual weight of P. cornucopiae treated with $Na_2SeO_3$ between 100 and $400{\mu}g/50g$ was between 129 and 138g/850cc. It was increased 4.9~12.2% as compared to 123g/850cc of the control but $500{\mu}g/50g$ was 122g/50g. Accumulation amount of organic selenium for P. cornucopiae treated with $Na_2SeO_3$ between 100 and $500{\mu}g/50g$ was $2.73{\sim}8.19{\mu}g/g/dry$. It was increased 55~164 times as the concentration increased when compared to $0.05{\mu}g/g/dry$ of the control. In conclusion, incubation period, mycelial density, DPI, number of valid stipes, individual weight and accumulation amounts of organic selenium for P. cornucopiae by treating 100, ${\sim}400{\mu}g$ of $Na_2SeO_3$ was increased, but $500{\mu}g/50g$ was reduced. So more than $500{\mu}g/50g$ concentration treatments are required research.