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Lee, Hyungbeen,Lee, Sang Won,Lee, Gyudo,Lee, Wonseok,Nam, Kihwan,Lee, Jeong Hoon,Hwang, Kyo Seon,Yang, Jaemoon,Lee, Hyeyoung,Kim, Sangsig,Lee, Sang Woo,Yoon, Dae Sung The Royal Society of Chemistry 2018 Nanoscale Vol.10 No.2
<P>Here, we demonstrate a powerful method to discriminate DNA mismatches at single-nucleotide resolution from 0 to 5 mismatches (<I>χ</I>0 to <I>χ</I>5) using Kelvin probe force microscopy (KPFM). Using our previously developed method, we quantified the surface potentials (SPs) of individual DNA-capped nanoparticles (DCNPs, ∼100 nm). On each DCNP, DNA hybridization occurs between ∼2200 immobilized probe DNA (<I>p</I>DNA) and target DNA with mismatches (<I>t</I>DNA, ∼80 nM). Thus, each DCNP used in the bioassay (each <I>p</I>DNA-<I>t</I>DNA interaction) corresponds to a single ensemble in which a large number of <I>p</I>DNA-<I>t</I>DNA interactions take place. Moreover, one KPFM image can scan at least dozens of ensembles, which allows statistical analysis (<I>i.e.</I>, an ensemble average) of many bioassay cases (ensembles) under the same conditions. We found that as the <I>χ</I>n increased from <I>χ</I>0 to <I>χ</I>5 in the tDNA, the average SP of dozens of ensembles (DCNPs) was attenuated owing to fewer hybridization events between the <I>p</I>DNA and the <I>t</I>DNA. Remarkably, the SP attenuation <I>vs.</I> the <I>χ</I>n showed an inverse-linear correlation, albeit the equilibrium constant for DNA hybridization exponentially decreased asymptotically as the <I>χ</I>n increased. In addition, we observed a cascade reaction at a 100-fold lower concentration of <I>t</I>DNA (∼0.8 nM); the average SP of DCNPs exhibited no significant decrease but rather split into two separate states (no-hybridization <I>vs.</I> full-hybridization). Compared to complementary <I>t</I>DNA (<I>i.e.</I>, <I>χ</I>0), the ratio of no-hybridization/full-hybridization within a given set of DCNPs became ∼1.6 times higher in the presence of tDNA with single mismatches (<I>i.e.</I>, <I>χ</I>1). The results imply that our method opens new avenues not only in the research on the DNA hybridization mechanism in the presence of DNA mismatches but also in the development of a robust technology for DNA mismatch detection.</P>
Development of an infant formula certified reference material for the analysis of organic nutrients
Lee, Joonhee,Kim, Byungjoo,Lee, Sun Young,Choi, Jongoh,Kang, Dukjin,Lee, Hwasim,Choi, KiHwan,Lee, Hyeyoung,Sim, Hee-Jung,Baek, Song-Yee,Lee, Honghee,Hyung, Seok-Won,Ahn, Seonghee,Seo, Dongwon,Hwang, J Applied Science Publishers 2019 Food chemistry Vol.298 No.-
<P><B>Abstract</B></P> <P>Infant formula certified reference material (CRM, KRISS CRM 108-02-003) were developed for the analysis of organic nutrients. The CRM is a milk-based infant formula powder, packaged at 14 g per unit. Ten thousand units were prepared and stored at −70 °C. For the certification of each nutrient, ten units were analyzed for simultaneous value-assignment and homogeneity test. Analytical methods used were isotope dilution mass spectrometry (IDMS) based on liquid chromatography mass spectrometer (LC/MS) or gas chromatography mass spectrometer (GC/MS) as higher-order reference methods.13 vitamins, 3 fatty acids, and total cholesterol were certified. The between-unit relative standard deviation of measurement results for each nutrient ranged 0.2% to 2.5%, showing very good homogeneity. The expanded relative uncertainties of the certified values ranged from 1% to 8%, indicating that they have higher-order metrological quality. The values of proximates (proteins, lipids, carbohydrates, water, and ash) were assigned through inter-laboratory comparisons.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An infant formula CRMs for the analysis of organic nutrients was developed. </LI> <LI> Organic nutrients were certified by IDMS approaches as higher-order reference methods. </LI> <LI> Homogeneities and stability of the CRM were evaluated by IDMS approaches. </LI> <LI> Metrological qualities of the certified values were proved by their small uncertainties. </LI> <LI> Five proximates were value-assigned by interlaboratory comparison. </LI> </UL> </P>
Seok, Seung-Hyeok,Koo, Hye Cheong,Kasuga, Asako,Kim, Yeun,Lee, Eun Gae,Lee, Hyeyoung,Park, Jong-Hwan,Baek, Min-Won,Lee, Hui-Young,Kim, Dong-Jae,Lee, Byeung-Hee,Lee, Yong-Soon,Cho, Sang-Nae,Park, Jae-H Elsevier 2006 Veterinary microbiology Vol.114 No.3
<P><B>Abstract</B></P><P>Skin ulcers, scoliosis, and dropsy-like scale edema were observed in laboratory-maintained zebrafish. Affected fish had multifocal granulomas not only in internal organs such as the liver, intestine, genital organs, kidney, muscle, and spleen but also in the fin, epithelium, gills, and sclera of the eyes. Large numbers of acid-fast-rod-shaped bacteria were observed within the necrotic centers of well-demarcated, multifocal granulomas with Gram's stain and Ziehl–Neelson's stain. The size of the <I>Mycobacterium</I> spp. was 1–2μm×2–3μm with a double-layered cell wall, based upon electron-microscopical features. Definitive diagnosis of these outbreaks was obtained by culture on selective media followed by PCR-restriction fragment length polymorphism analysis (PRA) of the <I>rpoB</I> gene for species identification. The amplified 360-bp products of the <I>rpoB</I> gene of mycobacteria isolated from zebrafish were digested with <I>Msp</I>I restriction enzyme, which revealed unique band patterns matching those of <I>Mycobacterium abscessus</I> and <I>Mycobacterium chelonae</I> which are responsible for skin and soft tissue infection caused by rapidly growing mycobacteria in humans. This is the first documentation of the precise identification of zoonotic non-tuberculous mycobacteria isolated from laboratory-maintained zebrafish by the PRA of the <I>rpoB</I> gene; this study thus provides a great deal of useful epidemiological information and reduces the likelihood that epizootics will occur.</P>
Hyeyoung Jeon(전혜영),Seulah Lee(이슬아),Seonguk Yang(양성욱),EunJin Bang(방은진),Il Young Ryu(유일영),Yujin Park(박유진),Hee Jin Jung(정희진),Hae Young Chung(정해영),Hyung Ryong Moon(문형룡),Jaewon Lee(이재원) 한국생명과학회 2021 생명과학회지 Vol.31 No.8
멜라닌 색소는 포유동물의 피부, 머리카락, 눈, 신경계에 풍부하게 존재한다. 멜라닌은 다양한 환경적 스트레스로부터 피부를 보호하며, 생리학적 산화-환원 완충 작용을 통해 항상성을 유지한다. 그러나, 과도한 멜라닌 축적은 간반, 주근깨, 노인성 흑자, 염증성 색소침착을 일으킬 수 있다. 티로시나아제는 멜라닌의 생합성 경로 조절에 아주 중요한 역할을 하는 것으로 알려져 있다. 티로시나아제의 활성을 저해하는 다양한 미백제가 개발되었지만 알러지, DNA손상, 세포독성, 돌연변이 유발 등을 야기하는 부작용으로 인해 임상적 적용이 제한되었다. 본 논문에서 여러 4-크로마논 유도체를 합성하여 티로시나아제 억제 활성을 조사하였다. 이들 화합물 중 MHY1294는 IC50가 5.1±0.86 μM으로 양성 대조군인 코직산(14.3±1.43 μM) 보다 나은 티로시나아제 효소 억제 활성을 나타냈다. 또한 MHY1294는 티로시나아제의 촉매 부위에서 경쟁적인 억제 작용을 보였으며 코직산보다 더 큰 기질 결합 친화성을 가지는 것으로 확인되었다. 뿐만 아니라, MHY1294는 B16F10 흑색종 세포에서 멜라닌 세포 자극 호르몬(α-MSH)에 의해 유도되는 멜라닌 합성과 세포 내 티로시나아제 활성을 유의적으로 억제하였다. 결론적으로 본 연구는 MHY1294가 과도한 멜라닌 축적에 대한 약물 제제 및 미백제로서의 개발 가능성이 있음을 시사한다. Melanin pigments are abundantly distributed in mammalian skin, hair, eyes, and nervous system. Under normal physiological conditions, melanin protects the skin against various environmental stresses and acts as a physiological redox buffer to maintain homeostasis. However, abnormal melanin accumulation results in various hyperpigmentation conditions, such as chloasma, freckles, senile lentigo, and inflammatory pigmentation. Tyrosinase, a copper-containing enzyme, plays an important role in the regulation of the melanin pigment biosynthetic pathway. Although several whitening agents based on tyrosinase inhibition have been developed, their side effects, such as allergies, DNA damage, mutagenesis, and cytotoxicity of melanocytes, limit their applications. In this study, we synthesized 4-chromanone derivatives (MHY compounds) and investigated their ability to inhibit tyrosinase activity. Of these compounds, (E)-3-(4-hydroxybenzylidene)chroman-4-one (MHY1294) more potently inhibited the enzymatic activity of tyrosinase (IC50 = 5.1±0.86 μM) than kojic acid (14.3±1.43 μM), a representative tyrosinase inhibitor. In addition, MHY1294 showed competitive inhibitory action at the catalytic site of tyrosinase and had greater binding affinity at this site than kojic acid. Furthermore, MHY1294 effectively inhibited α-melanocyte stimulating hormone (α-MSH)-induced melanin synthesis and intracellular tyrosinase activity in B16F10 melanoma cells. The results of the present study indicate that MHY1294 may be considered as a candidate pharmacological agent and cosmetic whitening ingredient.
Lee, Hyeyoung,Park, Ki Hyun,Park, Hye Sun,Ryu, Ji Hyeong,Lim, Jihyang,Kim, Yonggoo,Na, Gun Hyung,Kim, Dong Goo,Oh, Eun-Jee The Korean Society for Laboratory Medicine 2017 Annals of Laboratory Medicine Vol.37 No.1
<P><B>Background</B></P><P>The interaction between killer immunoglobulin-like receptors (KIRs) and HLA class I regulates natural killer (NK) cell cytotoxicity and function. The impact of NK cell alloreactivity through KIR in liver transplantation remains unelucidated. Since the frequency of HLA-C and KIR genotypes show ethnic differences, we assessed the impact of HLA-C, KIR genotype, or KIR-ligand mismatch on the allograft outcome of Korean liver allografts.</P><P><B>Methods</B></P><P>One hundred eighty-two living donor liver transplant patients were studied. Thirty-five patients (19.2%) had biopsy-confirmed acute rejection (AR), and eighteen (9.9%) had graft failure. The HLA-C compatibility, KIR genotypes, ligand-ligand, and KIR-ligand matching was retrospectively investigated for association with allograft outcomes.</P><P><B>Results</B></P><P>Homozygous C1 ligands were predominant in both patients and donors, and frequency of the HLA-C2 allele in Koreans was lower than that in other ethnic groups. Despite the significantly lower frequency of the HLA-C2 genotype in Koreans, donors with at least one HLA-C2 allele showed higher rates of AR than donors with no HLA-C2 alleles (29.2% vs 15.7%, <I>P</I>=0.0423). Although KIR genotypes also showed ethnic differences, KIR genotypes and the number of activating KIR/inhibitory KIR were not associated with the allograft outcome. KIR-ligand mismatch was expected in 31.6% of Korean liver transplants and had no impact on AR or graft survival.</P><P><B>Conclusions</B></P><P>This study could not confirm the clinical impact of KIR genotypes and KIR-ligand mismatch. However, we demonstrated that the presence of HLA-C2 allele in the donor influenced AR of Korean liver allografts.</P>