• Journal of the Korean Magnetic Resonance Society
• /
• v.4 no.2
• /
• pp.133-139
• /
• 2000

The strategy to incorporate [$^{15}$ N]-labeled amino acids were discussed. Instead of using specific auxotrophic strains for selective labeling, the prototrophic strain, BL2l(DE3), was used with a plasmid, pLysS, and found to be very effective for several amino acids including alanine, lysine, leucine, and threonine. Isoleucine, valine, glutamine, and tyrosine were also found to be effective despite some diffusion into other amino acids. Interesting result was obtained when [$^{15}$ N]-labeled glycine was tried: only glycines were labeled when amino acid mixture was added in the growth medium, and serines were co-labeled when amino acids were omitted. These results can be used as a guideline when selective labeling strategy is considered, and when the resulting data are interpreted.

• Proceedings of the Korean Society of Grassland Science Conference
• /
• 1999.06a
• /
• pp.82-83
• /
• 1999

탄소 및 질소동화의 상관성을 규명하기 위해 $^{13}$C(pulse chase)와 $^{15}$ N(continuous)을 labeling 한 후 6시간 동안 탄소 및 질소대사물로 동화된 동위원소를 분석하여 엽신, 엽병 및 뿌리조직 사이의 대사적 교감에 있어 탄소 및 질소 동화산물의 역할을 살펴보았다 $^{13}$$CO_2$로 75분간 labeling 한 후(0h), 광합성에 의해 고정된 $^{13}$C는 엽신에서 당의 형태로 주로 동화되었다.(중략)

• Journal of the Korean Magnetic Resonance Society
• /
• v.15 no.2
• /
• pp.115-127
• /
• 2011

A newly developed cost-effective approach to prepare $^{15}N/^{13}C$-labeled protein for NMR studies is presented. This method has been successfully applied to isotopically labeling of PTK6 SH2 domain and MTH 1880 protein. The production method generates cell density using a growing media containing $^{15}NH_4Cl$, $^{12}C_6$-D-glucose. Following a doubling time period for unlabeled metabolite exhaustion and then addition $^{13}C_6$-D-glucose into a M9 growing media, the cells are induced. Our results demonstrate that in order to get full incorporation of $^{13}C$, the isotopes are not totally required during the initial growth phase before induction. The addition of small amounts of $^{13}C_6$-D-glucose to the induction phase is sufficient to obtain more than 95% incorporation of isotopes into the protein. Our optimized protocol is two-thirds less costly than the classical method using $^{13}C$ isotope during the entire growth phase.

• Journal of Nutrition and Health
• /
• v.45 no.2
• /
• pp.150-158
• /
• 2012

This study was conducted to investigate the relationship between knowledge of nutrition labeling and the effect on eating habits with 300 high school boys in Seoul. The subjects were divided into an underweight (UW) group (BMI < $18.5kg/m^2$, n = 42), a normal weight (NW) group ($18.5kg/m^2\;{\leq}\;BMI\;<\;23kg/m^2$, n = 129) and an overweight (OW) group (BMI ${\geq}\;23kg/m^2$, n = 79) based on their body mass index (BMI). The average age of participants was 17.8 years old and their mean height and weight were 174.9 cm and 66.5 kg. The mean BMI of subjects was $21.7kg/m^2$ which fell within the normal range. Seventy six point four percent of subjects perceived nutrition labeling and they acquired the information pertaining to it through TV and internet. The UW group and the OW group obtained it from their parents, relatives and friends, while NW group acquired it from school. There were significant differences among groups in the acquired source of the information on nutrition labeling (p < 0.05). The NW group and the OW group trusted nutrition labeling more than the UW group, but there were no significant differences among them. Forty five point five percent of the UW group and 40.7% the NW group were satisfied with nutrition labeling education, while only 15.8% of the OW group did it. The OW group checked nutrition labeling more than the UW group and the NW group at the point of food purchase. The primary reason for examining nutrition labeling was 'to check nutrient contents' in the UW group and the NW group, while the OW group examined it to improve health including regulation of body weight. There were significant differences among groups with regards to the reason for examining nutrition labeling (p < 0.001). The OW group was aware that nutrition labeling affected their eating ha-bits significantly more than the other groups (p < 0.05). Therefore, application-centered education on nutrition labeling and the strong support of the government is needed in order to improve nutrition labeling use and to apply the information from nutrition labeling into student dietary life.

• Journal of the Korean Magnetic Resonance Society
• /
• v.14 no.2
• /
• pp.117-126
• /
• 2010

Hsp33 is a molecular chaperone achieving a holdase activity upon response to a dual stress by heat and oxidation. Despite several crystal structures available, the activation process is not clearly understood, because the structure inactive Hsp33 as its reduced, zinc-bound, monomeric form has not been solved yet. Thus, we initiated structural investigation of the reduced Hsp33 monomer by NMR. In this study, to overcome the high molecular weight (33 kDa), the protein was triply isotope-[$^{13}C$, $^{15}N$, $^2H$]-labeled and its inactive, monomeric state was ensured. 2D-[$^1H$, $^{15}N$]-TROSY and a series of triple resonance spectra could be successfully obtained on a high-field (900 MHz) NMR machine with a cryoprobe. However, under all of the different conditions tested, the number of resonances observed was significantly less than that expected from the amino acid sequence. Thus, a possible contribution of dynamic conformational exchange leading to a line broadening is suggested that might be important for activation process of Hsp33.

• Journal of the Korean Magnetic Resonance Society
• /
• v.24 no.3
• /
• pp.77-85
• /
• 2020

Stable isotope enrichment in proteins is necessary for high-resolution nuclear magnetic resonance (NMR) experiments. Although methods for ¹³C, ¹⁵N and ²H-enrichment in prokaryotic cells are well established, full processing and correct folding of complex protein systems require higher organisms as the expression host. In the present study, we review recent efforts to enrich stable isotopes in mammalian cells for protein NMR studies.

• Korean Journal of Community Nutrition
• /
• v.21 no.6
• /
• pp.574-579
• /
• 2016

Objectives: Vitamin C has various functions such as antioxidative effect and supporting absorption of iron (Fe). Aim of this present study was to provide vitamin C nutrition information and to briefly evaluate absorption interaction of vitamin C and Fe content of vitamin C emphasized products. Methods: Vitamin C emphasized foods including beverages, cereal, snacks, chocolate products, other cocoa products, and sugary products were examined by HPLC. Fe contents in samples after dry-ashing were examined by ICP. Results: Vitamin C content ranges in various products tested were the following: beverages (n=11) $20.15{\pm}0.08{\sim}845.41{\pm}6.07mg$, cereal (n=11) $52.50{\pm}0.23{\sim}262.50{\pm}0.07mg$, snacks (n=1) $50.00{\pm}0.25mg$, chocolate products (n=1) $311.73{\pm}2.44mg$, other cocoa products (n=1) $311.73{\pm}2.44mg$, other sugary products (n=2) $52.50{\pm}0.23{\sim}262.50{\pm}0.07mg$. Vitamin C (n=27) analysis values ranged from 82 to 450% of the labeled value. Vitamin C content in vitamin C emphasized food (n=6) was estimated 7.7 times~56.6 times more than Fe content. Conclusions: Analyzed samples ranged more than 80% of the labeled value in vitamin C emphasized products, which complied with food labeling regulation. But, beverages (n=3), cereal (n=4), chocolate products (n=1) were 2 times more than the labeled value. To provide accurate nutrition information, food manufactures should supervise nutrition labeling and understand the interactions between nutrients. Also, consumer should decide about the adequate amount of nutrient intake by thoroughly checking nutrition labeling.

• The Korean Journal of Nuclear Medicine
• /
• v.33 no.4
• /
• pp.430-438
• /
• 1999

Purpose: We evaluated a rapid preparation procedures for the labeling and quality control of $^{99m}Tc$-ECD, $MAG_3$, and MIBI using microwave heating and Sep-Pak cartridges. Materials and Methods: $^{99m}Tc$ labeling of ECD, $MAG_3$, and MIBI kit preparation was performed according to the package inserts with microwave heating modification. Heating time was 10-15 sec, and heating was performed with 3 mm plastic bottle with screw cap to prevent radiation contamination. Labeling efficiency was obtained with $C_{18}$ or Alumina N Sep-Pak cartridges. Results: The radiochemical purity of $93{\sim}96%$ for $^{99m}Tc$-ECD and $95{\sim}99%$ for $^{99m}Tc$-MIBI was obtained using Alumina N Sep-Pak cartridge. The optimum irradiation time of microwave method for 3 ml $^{99m}Tc$-labeled radiopharmaceutical solution was 10 sec for $^{99m}Tc$-ECD and $^{99m}Tc$-MIBI, and 15 sec for $^{99m}Tc-MAG_3$. The results of quality control data with Sep-Pak cartridges were well correlated with TLC method. The total preparation time of these radiopharmcaeuticals was $5{\sim}6min$ including quality control procedure. Conclusion: This study demonstrates that radiopharmaceuticals preparation by microwave heating and quality control by Sep-Pak cartridges can be efficiently utilized as an alternative to the recommended method by manufacturer's manual.

• YAKHAK HOEJI
• /
• v.39 no.5
• /
• pp.516-520
• /
• 1995

The anti-dansyl antibodies were specifically labeled with stable isotope by growing hybridoma cells in serum-free medium. Assignments of the observed carbonyl carbon resonances have been determined by using $^{13}C-{15}N$ double labeling method in order to assign the Leu resonances. However, when the identical dipeptide appears more than twice in the polypeptide sequences, we applied the proteolytic fragments in the fragment-specific method. Carboxypep-tidase B-treated antibody has also been used to assign the Lys-447 in C terminal amino acid. These unambiguously assigned carbonyl carbon resonances in antibodies are thought to be useful in elucidating not only the structure of antibodies but also the structure-function relationship in the antibody by $^{13}C$ neuclear magnetic resonance spectroscopy.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.31 no.3
• /
• pp.277-284
• /
• 2011

To investigate the effects of arbuscular mycorrhizal (AM) symbiosis on N uptake and its assimilation under drought-stressed conditions in white clover, total $^{15}N$ amount and $^{15}N$ amount incorporated into $NO_3^-$, amino acids and soluble proteins were quantified by $^{15}N$ tracing during 7 days of water treatment. Under well-watered conditions, there were no significant effects of AM symbiosis on all parameters analyzed in this study. Drought stress decreased total $^{15}N$ amount both in AM and non-AM plants, with a lower rate in AM plants (-13.8%) relative to non-AM plants (-28.5%) at day 7. Drought significantly increased $^{15}N-NO_3^-$ amount in non-AM plants. The amount of $^{15}N$-amino acids was 1.26-fold and 1.33-fold higher, respectively, in leaves and roots of AM plants compared to those of non-AM ones. Drought decreased the amount of $^{15}N$-soluble proteins in leaves at day 7, with a higher rate in non-AM plants than in AM ones. These results clearly indicate that AM colonization effectively alleviating the decrease in N uptake, amino acids and proteins synthesis caused by drought stress.