http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Choi, Min-Sue,Yoon, In-Sun,Rhee, Yong,Choi, Seung-Kook,Lim, Sun-Hyung,Won, So-Youn,Lee, Yeon-Hee,Choi, Hong-Soo,Lee, Suk-Chan,Kim, Kook-Hyung,Lomonossoff, George,Sohn, Seong-Han The Korean Society of Plant Pathology 2008 Plant Pathology Journal Vol.24 No.3
The transient and rapid expression system of a foreign protein in planta is a very useful technique in biotechnology application. We have investigated optimum condition of Agrobacterium-infiltration technique in which expression level of foreign proteins were maximized without detrimental effects on plants using GFP and Cucumber mosaic virus 2b protein, which is known as an enhancer of gene expression and a suppressor of post-transcriptional gene silencing(PTGS). The optimum expression level of both RNA and protein of GFP with minimum leaf impairment was obtained at $OD_{600}$=0.2 of Agrobactrium inocula. The steady-state levels of GFP RNA and protein generally peaked at 3 and 7 days post-infiltration(dpi), respectively. In the presence of 2b, both the magnitude and duration of GFP expression was highly increased and we could detect GFP level until 17 dpi. On the other hands, the 2b-mediated higher accumulation of foreign proteins resulted in the repression of normal leaf growth, possibly due to the limitation of supply of energy or materials required for growth maintenance. Using this Agrobacterium-infiltration system with 2b and GFP, we tested a hypothesis for the threshold model of PTGS initiation. Four GFP transgenic lines of N. benthamiana, which shows different expression level of GFP were tested to determine the threshold level for PTGS initiation. Agrobacterium-infiltration of GFP into those GFP-transgenic plants resulted in the co-silencing of the transgenic GFP. It was found that very low concentration of Agrobacterium with GFP and GFP+2b($OD_{600}$=0.002-0.02) which could not phenotypically induce an additive GFP expression, was enough to trigger PTGS pathway in all GFP transgenic plants. This strongly indicates that each GFP-transgenic plant should be expressing the transgenic GFP at its own pre-determined level and there was no buffer zone of additive GFP-expression to the threshold. In other words, the PTGS seems to be immediately activated as a self-defensive mechanism if an internal balance of gene expression is broken.
Choi, Yeon Ja,Kim, Hyung Suk,Lee, Juyoun,Chung, Jin,Lee, Jun Sik,Choi, Jae Sue,Yoon, Taek Rim,Kim, Hyung Keun,Chung, Hae Young 대한약학회 2014 Archives of Pharmacal Research Vol.37 No.8
Oxidative stress has been proposed to be a major cause of aging and many age-related diseases. Peroxynitrite ($ONOO^-$), formed from the reaction of superoxide ($^{\bullet}O_2{^-}$) and nitric oxide (NO), is a cytotoxic species that can oxidize various cellular components, such as proteins, lipids, and DNA. The present study investigated whether dimethyl lithospermate (DML), isolated from Salvia miltiorrhiza, modulates age-related increases of $ONOO^-$, NO, and reactive species (RS) levels and expressions of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). For this study, 20-month-old rats were intraperitoneally injected with 5 or 10 mg/kg/day of DML, and 6-month-old rats were used as young control animals. Our results indicated that DML reduces $ONOO^-$ levels in a dose-dependent manner. The data also revealed that DML has significant inhibitory effects on NO metabolites and RS generation in a dose-dependent manner during aging. Furthermore, the results of Western blot analysis revealed that DML treatment reduces age-associated increases in COX-2 and iNOS expressions. Thus, this study found that DML caused the decrease of renal oxidative stress and COX-2 and iNOS expressions in aged rats. The significance of the present study is the finding of DML in its potential application against the aging process.
Choi, Sue Hyung,Moon, Seung Hyeon,Lee, Jae Suk,Gu, Man Bock 한국미생물 · 생명공학회 2000 Journal of microbiology and biotechnology Vol.10 No.6
Cell-free culture broth of Phanerochaete chrysosporiwn has been adopted to biologically degrade 2,4,5-trichlorophenol. Two different medium compositions of nitrogen-sufficient and nitrogen-limited were compared for their distribution of isozymes, activity of lignin peroxidase, and production of oxalate. The two different culture broths were tested for their ability to degrade 2,4,5-trichlorophenol, and the biodegradation efficiency was estimated in terms of the disappearance of 2,4,5-trichlorophenol. The degradation efficiency for the nitrogen-limited culture broth was higher than that of the nitrogen-sufficient culture broth, since the nitrogen-limited culture broth induced lignin peroxidases (LiPs) and manganese peroxidases (MnPs), and contained sufficient oxalate for producing necessary radicals. Finally, the possible mechanism of 2,4,5-CP degradation using the nitrogen-limited culture broth was proposed.
Phytochemical Study on Aloe vera
Choi, Jae-Sue,Lee, Seung-Ki,Sung, Chung-Ki,Jung, Jee-Hyung The Pharmaceutical Society of Korea 1996 Archives of Pharmacal Research Vol.19 No.2
Aloe plants have been used as herbal medicine for centuries and the name aloe means the dried exudate from the cut leaves of Aloe ferox Mill. (Cape aloe, Liliaceae), Aloe ferryi Baker. (Socotrine aloe), A. bainesii Th. Dyer. (Natal aloe) and Aloe vera L. (Curacao aloe) (Namba, 1986). Among them, Aloe vera has not only been one of the most used natural drug well known for its cathartic properties, but also has been widely used as raw materials of cosmetics and health foods (Leung, 1978, Hoffenberg, 1979). Although previous investigations showed that the leaves of A. vera contain a number of anthracene and chromone derivatives such as aloin A, aloin B, 1, 3, 6, 8-tetra-nitro-4,5-dihydroxy-2-hydroxymethyl anthraquinone and 7-hydroxy-aloin, its chemical composition is far from being completely investigated (Hoffenberg, 1979, Rauwald and Voetig, 1982). As a part of our chemical investigations on the constituents of aloe, we report chemical investigation of the freeze dried ground leaves of A. vera which is led to the isolation of five compounds from the ethyl acetate soluble fraction of the methanolic extract.
The NMR assignments of anthraquinones from Cassia tora
Choi, Jae-Sue,Jung, Jee-Hyung,Lee, Hee-Jung,Kang, Sam-Sik The Pharmaceutical Society of Korea 1996 Archives of Pharmacal Research Vol.19 No.4
The $^1H- and^{13}C-NMR$ spectra of alaternin, aurantio-obtusin, chryso-obtusin, obtusin and 2-glucosyl obtusifolin isolated from the seeds of Cassia tora have been assigned based on HMBC, long-range HETCOR, fully $^1H-coupled {13}^C-NMR$, deuterium isotope experiment, and by comparison with the model compounds.
Choi, Jae Sue,Jung, Jee Hyung,Jung, Ji Hyeon Lee 한국수산학회 1997 한국수산과학회지 Vol.30 No.6
The nitrite scavenging effect of methanol extracts of marine algae were evaluated to discover new natural nitrite scavengers. Among the tested seaweeds, Ecklonia stolonifera, an edible brown algae, showed the strongest scavenging effect. The MeOH extract was then sequentially partitioned into CH₂Cl₂, CH₂Cl₂, insoluble interface, EtOAc, n-BuOH, and H₂O layers. Tire EtOAc and n-BuOH fraction demonstrated high levels of nitrite-scavenging activity while the CH₂Cl₂, CH₂Cl₂, insoluble interface, and H₂O fractions were inactive. A column chromatography of the EtOAc fraction through silica gel and Sephadex LH-20 yielded phloroglucinol and a new compound tentatively named phlorotannin A. The nitrite scavenging activity of phloroglucinol(IC_(50)=3.9㎍/㎖) was more potent than that of L-ascorbic acid(IC_(50)=65.0㎍/㎖). However, phlorotannin A(IC_(50)=193.2㎍/㎖) showed only low levels of activity. From the above results, it is possible to suggest that both the MeOH extract and their fractions and isolated phloroglucinol and phlorotannin A obtained from E. stolonifera may be applicable as scavengers of nitrite, which is a precursor for the formation of carcinogenic N-nitroso compounds.
Jae Sue Choi,Ji Hyeon Lee,Hae Jin Park,Hyung Geun Kim,Han Suk Young,Sook Im Mun 한국생약학회 1994 생약학회지 Vol.24 No.4
The antioxidant activity of methanol extracts of plants and marine algae was tested by using 1, 1-diphenyl-2-picrylhydrazyl(DPPH), Five plant extracts(Prunus davidiancc, Eriobotrya japonica, Artemisia iwayomogi, Stirodella tolyrrhiza and Ulmus davidiana) and two algae (Ecklonia stolonifera .and Symphycoladia latiuscula) were found to be the most effective in DPPH radical scavenging activity. The methanol extract obtained from the stems of Prunus davicliana was fractionated with several solvents. The ethylacetate soluble fraction exhibiting the strongest antioxidant activity was further purified by repeated silica gel and Sephadex LH-20 column chromatography. Antioxidant flavonoids and flavonoid glycosides were isolated and the most active ones was identified as (+)-catechin by MS, ¹H-NMR and <sup>13</sup>C-NMR. Its antioxidant activity was higher than that of vitamin C.