• Current Research on Agriculture and Life Sciences
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• v.4
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• pp.36-41
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• 1986

The transformation of Saccharomyces cerevisiae with YIp26, YRp7 and YEp13 was investigated. Transformation frequences of YIp5, YIp26, YRp7 and YEp13 in Escherichia coli HB101 was $5.1{\times}10^{-4}$, $1.5 {\times}10^{-3}$, $1.3{\times}10^{-3}$, $3{\times}10^{-3}$, respectively. When plasmids were used in covalently closed circular form, transformation frequency of YEp13 was $1.2{\times}10^{-4}$ in S. cerevisiae DBY747 and $3.3{\times}10^{-4}$ in S. cerevisiae MC16 and that of YRp7, YIp26 was $3{\times}10^{-6}$, below $6{\times}10^{-8}$ respectively in S. cerevisiae DBY747 by the method of Ito. Cotransformation of YIp26 and YEp13 in linear form increased the frequency of transformation with efficiences 270-fold higher than transformation of YIp26 only in S. cerevisiae DBY747. In cotransformation of YIp5+YEp13 and YIp26+YRp7 with S. cerevisiae DBY747 by Beggs' method. Expression frequency of YIp5+YEp13 and YIp26+YRp7 was $4{\times}10^{-6}$, $1.5{\times}10^{-6}$, respectively. The recombinant plasmid of cotransformant was thought that YIp26 and YEp13, YIp5 and YEp13, and YIp26 and YRp 7 were ligated in vivo in S. cerevisiae DBY747.

• Current Research on Agriculture and Life Sciences
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• v.5
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• pp.52-58
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• 1987

The yeast S. cerevisiae DBY747 was transformed with E. C - S. C shuttle vector YIp5, YEp13 and YRp7 by the method of spheroplast. The transformation frequency of YEp13 and YRp7 in S. cerevisiae DBY747 was $1.2{\times}10^3$ and $1.0{\times}10^2$ per $10{\mu}g$ of DNA, respectively. The transformants with YIp5 plasmid incapable of autonomous replication in S. cerevisiae were not detected in the condition of this experiment, but YIpS plasmid expressed the gene carried on it when cotransformed with a helper plasmid such as YEp13 or YRp7 : autonomously replicating plasmid. When plasmids were used in covalently closed circular form, cotransformation frequency of Ylp5-YEpl3 and Ylp5-YRp7 was 210 and 95 per $10{\mu}g$ of DNA, respectively. In cotransformation of linear plasmids, transformation frequency of the same cohesive ends was similar to that of noncomplementary cohesive ends. Transformants by the cotransformation with circular plasmids have been shown much higher frequency than with linear plasmids in S. cerevisiae DBY 747. The mitotic segregation stability test suggested that the cotransformant of YIpS-YEp13 was more stable than that of YIpS-YRp7.

• Journal of Environmental Health Sciences
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• v.47 no.6
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• pp.540-547
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• 2021

Background: Indoor air pollutants are caused by a number of factors, such as coming in from the outside or being generated by internal activities. Typical indoor air pollutants include nitrogen dioxide and carbon monoxide from household items such as heating appliances and volatile organic compounds from building materials. In addition there is carbon dioxide from human breathing and bacteria from speaking, coughing, and sneezing. Objectives: According to recent research results, most indoor air pollution is known to be greatly affected by internal factors such as burning (biomass for cooking) and various pollutants. These pollutants can have a fatal effect on the human body due to a lack of ventilation facilities. Methods: We fabricated a polydopamine (PDA) layer with Ti substrates as a coating on supported glass fiber fabric to enhance its photo-activity. The PDA layer with TiO₂ was covalently attached to glass fiber fabric using the drop-casting method. The roughness and functional groups of the surface of the Ti substrate/PDA coated glass fiber fabric were verified through infrared imaging microscopy and field emission scanning electron microscopy (FE-SEM). The obtained hybrid Ti substrate/PDA coated glass fiber fabric was investigated for photocatalytic activity by the removal of ammonia and an epidermal Staphylococcus aureus reduction test with lamp (250 nm, 405 nm wavelength) at 24℃. Results: Antibacterial properties were found to reduce epidermal staphylococcus aureus in the Ti substrate/PDA coated glass fiber fabric under 405 nm after three hours. In addition, the Ti substrate/PDA coated glass fiber fabric of VOC reduction rate for ammonia was 50% under 405 nm after 30 min. Conclusions: An electron-hole pair due to photoexcitation is generated in the PDA layer and transferred to the conduction band of TiO₂. This generates a superoxide radical that degrades ammonia and removes epidermal Staphylococcus aureus.

• IMMUNE NETWORK
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• v.22 no.5
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• pp.42.1-42.20
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• 2022

Vaccination with tumor peptide epitopes associated with MHC class I molecules is an attractive approach directed at inducing tumor-specific CTLs. However, challenges remain in improving the therapeutic efficacy of peptide epitope vaccines, including the low immunogenicity of peptide epitopes and insufficient stimulation of innate immune components in vivo. To overcome this, we aimed to develop and test an innovative strategy that elicits potent CTL responses against tumor epitopes. The essential feature of this strategy is vaccination using tumor epitope-loaded nanoparticles (NPs) in combination with polyinosinic-polycytidylic acid (poly-IC) and anti-PD1 mAb. Carboxylated NPs were prepared using poly(lactic-co-glycolic acid) and poly(ethylene/maleic anhydride), covalently conjugated with anti-H-2K^b mAbs, and then attached to H-2K^b molecules isolated from the tumor mass (H-2^b). Native peptides associated with the H-2K^b molecules of H-2K^b-attached NPs were exchanged with tumor peptide epitopes. Tumor peptide epitope-loaded NPs efficiently induced tumor-specific CTLs when used to immunize tumor-bearing mice as well as normal mice. This activity of the NPs significantly was increased when co-administered with poly-IC. Accordingly, the NPs exerted significant anti-tumor effects in mice implanted with EG7-OVA thymoma or B16-F10 melanoma, and the anti-tumor activity of the NPs was significantly increased when applied in combination with poly-IC. The most potent anti-tumor activity was observed when the NPs were co-administered with both poly-IC and anti-PD1 mAb. Immunization with tumor epitope-loaded NPs in combination with poly-IC and anti-PD1 mAb in tumor-bearing mice can be a powerful means to induce tumor-specific CTLs with therapeutic anti-tumor activity.

• Journal of Chest Surgery
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• v.31 no.11
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• pp.1023-1030
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• 1998

Background: Calcific degeneration limits durabilities of the bioprosthetic tissues implanted in the human body. The direct coupling sulphonated polyethyleneoxide(PEO-SO3) to the bioprosthetic tissues after glutaraldehyde(GA) fixation and the removal of residual aldehyde groups from the tissues can augment the effect of calcification-resistance. Materials and methods: To study the anti-calcification effect by PEO-SO3 modification and the removal of the residual aldehyde groups of tissues, surface modified bovine pericardia(BP-PEO-SO3) were preserved in aseptic saline to wash out GA(saline group) and 0.65% GA solution(GA group). And then above two groups and PERIGUARD (Bio-vascular. Co.) (product group) were evaluated with respects to calcium contents and microscopic findings using in vivo implantation models at carotid and femoral artery and peritoneum of 8 adult dogs. Results: In the tissues retrieved from carotid artery, calcium content was significantly decreased in saline group than in other two groups(saline; 2.89±0.31 vs. GA; 6.14±1.08 vs. product; 22.82±5.00 mg/g of dried tissue; p<0.05). In the tissues retrieved from femoral artery and peritoneum, calcium amount was also decreased in saline group than in other two groups, but not reached the significant difference between groups. On the other hand, the pathologic findings of pericardial tissues showed marked destructuction in GA group compared to the other two groups. Conclusions: In this study, covalently PEO-SO3 bound to bovine pericardium decreased calcifications and the anti-calcification effect of BP-PEO-SO3 could be augmented by the washing out the residual aldehyde groups using saline after GA fixation. Conclusively, the PEO-SO3 modified bovine pericardium is highly resistant to calcification and can be useful for the development of calcification-resistant cardiovascular patches and valves.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.2
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• pp.186-192
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• 1997

Increased activities of phase 2 enzymes including quinone reductase(QR) have been reported to be associated with protection of animals from neoplastic, mutagenic, and other toxic effects of many carcinogens. In previous study, we found that methanol extract of roasted and defatted perilla meal induced the activity of quinone reductase, an anticarcinogenic marker enzyme, in murine hepalc1c7 cells. Current study showed that unroasted perilla had a limited QR-inducing activity, suggesting that roasting cause the generation of active component(s). Thus we hypothesized that QR inducer in perilla might be covalently linked to sugar moiety and released during roasting process. Methanol extract of defatted raw perilla was subject to acid treatment in order to hydrolyze the potential sugar moiety. Prolonged hydrolysis of methanol extract of defatted raw perilla at $98{\sim}100^{\circ}C$ increased the ability to induce cytosolic QR activity of hepalclc7 cells. Furthermore roasting at 180 and $200^{\circ}C$ resulted in significant induction of QR activity. The result strongly support the idea that QR inducer(s) is present in bound form in raw perilla and released during roasting. Cellular QR activity was induced proportionately with the increase of concentration of methanol extract of roasted perilla. The induction of QR by defatted perilla was also examined in the cytosols of liver, small intestine, stomach, lung and kidney of male ICR mice. Induction patterns showed specificity with respect to target tissue and roasting of perilla. Unroasted perilla meal (defatted) significantly induced QR in liver and lung, while roasted perilla meal induced QR in liver and stomach. The observation that raw perilla showed similar QR induction patterns to roasted perilla is consistent with our proposal that QR inducer(s) is present in bound form and released by physical and chemical treatments as digestive or microbial enzymes could release the inducers from inactive glycoside forms in gastrointestinal tract of mice. In conclusion, perilla could exert protective effect against chemically induced carcinogenesis by inducing phase 2 enzymes in biological systems regardless of chemical and physical process such as roasting.

• Journal of the Korean Chemical Society
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• v.51 no.1
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• pp.43-50
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• 2007

Liposomes having particle size from several tens to hundreds nanometers are efficient carriers for injectable drug delivery. Enhancement of liposome stability in bloodstream has been studied because of its relatively short circulation time and fast clearance from human body by reticuloendothelial system (RES) in blood vessel. In this study, new disaccharide-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) derivatives in which lactose or sucrose as the disaccharide molecule was conjugated covalently to DSPE were synthesized. Liposomes of which surface had disaccharide molecules were prepared by incorporating the disaccharide-DSPE into liposomes as one of their lipid components. Particle size of the prepared liposomes was approximately 100 nm. The liposomes of which surface were modified with the disaccharide-DSPE showed -25 mV of zeta potential value due to the presence of hydroxyl groups on their surface, while the unmodified control liposomes showed -10 mV of zeta potential value. Loading efficiency of model drug, doxorubicin, into liposomes was about 90%. Stability of the disaccharide-modified liposomes in vitro was evaluated by monitoring the amount of protein adsorption and particle size of the liposomes in serum. Disaccharide-modified liposomes were more stable in serum than unmodified control liposomes or polyethyleneglycol (PEG)-modified liposomes due to less adsorption of serum protein and hence less increase of their particle size. The liposomes of which surface was modified with disaccharide-DSPE conjugate can be used as long-circulating carriers for drugs having high toxicity or short half-life time due to their enhanced stability in blood circulatory system.

• Journal of Yeungnam Medical Science
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• v.25 no.1
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• pp.1-18
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• 2008

Although Lamivudine and adefovir dipivoxil are efficacious drugs for preventing hepatocellular carcinoma (HCC) in chronic hepatitis B patients, their efficacy is far from completely satisfactory. The risk of liver cirrhosis and HCC begins to increase at an HBV DNA level of $10^4$ copies/ml. Even with latent or past HBV infection, episomal covalently closed circular DNA(cccDNA) plays a key rolein the persistence, relapse and resistance of HBV in its natural course or during therapy. The annual incidence of HCC in YUMC is 1.8% and 4.7% patients/year in the antiviral treatment and control groups, respectively. The ability to achieve a high rate of sustained HBV suppression with low risk of drug resistance is the ultimate goal in the treatment of chronic HBV infection. The efficacy of universal immunization with striking reductions in the prevalence of HBV in localized countries needs to be spread worldwide. With hepatitis B immunization and effective antiviral therapy, global control of HBV infection and HBV-related complications, including HCC, are possible by the end of the first half of the $21^{st}$ century.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.173-178
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• 2022

A lateral flow immunoassay (LFIA) method using carbon nanodot@silica as a signaling material was developed for analyzing the concentration of retinol-binding protein 4 (RBP4), one of the lung cancer biomarkers. Instead of antibodies mainly used as bioreceptors in nitrocellulose membranes in LFIA for protein detection, aptamers that are more economical, easy to store for a long time, and have strong affinities toward specific target proteins were used. A 5' terminal of biotin-modified aptamer specific to RBP4 was first reacted with neutravidin followed by spraying the mixture on the membrane in order to immobilize the aptamer in a porous membrane by the strong binding affinity between biotin and neutravidin. Carbon nanodot@silica nanoparticles with blue fluorescent signal covalently conjugated to the RBP4 antibody, and RBP4 were injected in a lateral flow manner on to the surface bound aptamer to form a sandwich complex. Surfactant concentrations, ionic strength, and additional blocking reagents were added to the running buffer solution to optimize the fluorescent signal off from the sandwich complex which was correlated to the concentration of RBP4. A 10 mM Tris (pH 7.4) running buffer containing 150 mM NaCl and 0.05% Tween-20 with 0.6 M ethanolamine as a blocking agent showed the optimum assay condition for carbon nanodot@silica-based LFIA. The results indicate that an aptamer, more economical and easier to store for a long time can be used as an alternative immobilizing probe for antibody in a LFIA device which can be used as a point-of-care diagnosis kit for lung cancer diseases.

• Investigative Magnetic Resonance Imaging
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• v.8 no.1
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• pp.32-41
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• 2004

Purpose : To measure the NMR relaxation properties of MnPC, to observe the characteristics of liver enhancement patterns on MR images in experimentally implanted rabbit VX2 tumor model, and to estimate the possibility of tissue specific contrast agent for MnPC in comparison with the hepatobiliary agent. Materials and Methods : Phthalocyanine (PC) was chelated with paramagnetic ions, manganese (Mn). 2.01 g (5.2 mmol) of phthalocyanine was mixed with 0.37 g (1.4 nlmol) of Mn chloride at $310^{\circ}C$ for 36 hours and then purified by chromatography ($CHCl_3:\;CH_3OH=98:2$, volume ratio) to obtain 1.04 g $(46\%)$ of MnPC (molecular weight = 2000 daltons). The T1/T2 relaxivity (R1/R2) for MnPC were determined at a 1.5 T (64 MHz) MR spectrometer. VX2 tumor model was experimentally implanted in the liver parenchyma of rabbits. All MR studies were performed on 1.5 T. The human extremity radio frequency coil of a bird cage type was employed. MR images were acquired at 17 to 24 days after VX2 carcinoma implantation.4 mmol/kg MnPC and 0.01 mmol/kg Mn-DPDP were injected via the ear vein of rabbits. T1-weighted images were obtained with spin-echo (TR/TE=516/14 msec) and fast multiplanar spoiled gradient recalled (TR/TE : 80/4 msec, $60^{\circ}$ flip angle) pulse sequence. Fast spin-echo (TR/TE=1200/85 msec) was used to obtain the T2-weighted images. Results : The value of T1/T2 relaxivity (R1/R2) of MnPC was $7.28\;mM^{-1}S^{-1}$ and $55.56\;mM^{-1}S^{-1}$ respectively at 1.5 T (64 MHz). Because the T2 relaxivity of MnPC that bonded strongly, covalently manganese with phthalocyanine was very high, the signal intensity of liver parenchyma was decreased on postcontrast T2-weighted images and we could easily distinguish the VX2 carcinoma within the liver parenchyma. When MnPC was administrated intravenously, the tumor margin delineation was more remarkable than Mn-DPDP-enhanced images. The enhancement of liver parenchyma with MnPC persisted at relatively high levels over at least one hour after injection of the contrast agents. Conclusion : The hepatic uptake and biliary excretion of MnPC, which are similar to Mn-DPDP, suggest that this agent is a new liver-specific agent. Also, MnPC seems to be used as a dual contrast agent (T1 and T2) with high T2 relaxivity. However, it is warranted that MnPC needs further investigation as a potential contrast agent for MR imaging of the liver. That is, further characterizations of MnPC are needed in vivo and in vitro before clinical trials. The diagnostic potential of MnPC will also have to be examined more in the animal models of additional types.