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폐결핵치료 중인 환자에서 Rifampicin에 의해 유발된 위막성 대장염 2예
김봉진,권균홍,임창섭,김자영,홍정범,옥미선,배용목,김지연 고신대학교의과대학 2008 고신대학교 의과대학 학술지 Vol.23 No.4
Pseudomembranous colitis (PMC) is a disease caused by Clostridium difficile proliferation. The causative drugs are clindamycin, third-generation cephalosporins, flouroquinolone and so on. Rifampicin has been reported as a cause of PMC in the 1980s, and the frequency of PMC is increasing because rifampicin is a first line drug for anti-tuberculosis therapy. Two patients were recently admitted to our hospital due to watery diarrhea for 1 month and they were diagnosed with PMC by sigmoidoscopy. Their onset age were 74, 72 years old and latent period of symptoms were 60, 129 days, respectively. In one case, the patient displayed coexisting hypertension and diabetes. The clinical symptoms improved after discontinuing the rifampicin and then administering oral metronidazole. We report here on two cases presumed to be rifampicin-induced PMC.
The Cofactors Role on Chemical Mechanism of Recombinant Acetohydroxy Acid Synthase from Tobacco
Kim, Joung-Mok,Kim, Jung-Rim,Kim, Young-Tae,Choi, Jung-Do,Yoon, Moon-Young Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.5
Acetohydroxy acid synthase (AHAS) is one of several enzymes that require thiamine diphosphate and a divalent cation as essential cofactors. The active site contains several conserved ionizable groups and all of these appear to be important as judged by the fact that mutation diminishes or abolishes catalytic activity. Recently, we have shown [Yoon, M.-Y., Hwang, J.-H., Choi, M.-K., Baek, D.-K., Kim, J., Kim, Y.-T., Choi, J.-D. FEBS Letters 555 (2003), 185-191] that the activity is pH-dependent due to changes in $V_{max}$ and V/$K_m$. Data were consistent with a mechanism in which substrate was selectively catalyzed by the enzyme with an unprotonated base having a pK 6.48, and a protonated group having a pK of 8.25 for catalysis. Here, we have in detail studied the pH dependence of the kinetic parameters of the cofactors (ThDP, FAD, $Mg^{2+}$) in order to obtain information about the chemical mechanism in the active site. The $V_{max}$ of kinetic parameters for all cofactors was pH-dependent on the basic side. The pK of ThDP, FAD and $Mg^{2+}$ was 9.5, 9.3 and 10.1, respectively. The V/$K_m$ of kinetic parameters for all cofactors was pH-dependent on the acidic and on the basic side. The pK of ThDP, FAD and $Mg^{2+}$ was 6.2-6.4 on the acidic side and 9.0-9.1 on the basic side. The well-conserved histidine mutant (H392) did not affect the pH-dependence of the kinetic parameters. The data are discussed in terms of the acid-base chemical mechanism.
Kim, Joung Sug,Chae, Songhwa,Jun, Kyong Mi,Pahk, Yoon-Mok,Lee, Tae-Ho,Chung, Pil Joong,Kim, Yeon-Ki,Nahm, Baek Hie Springer US 2017 Rice Vol.10 No.-
<P><B>Background</B></P><P>Spatial- and temporal-specific expression patterns are primarily regulated at the transcriptional level by gene promoters. Therefore, it is important to identify the binding motifs of transcription factors to better understand the networks associated with embryogenesis.</P><P><B>Results</B></P><P>Here, we used a protein-binding microarray (PBM) to identify the binding motifs of OsSMF1, which is a basic leucine zipper transcription <B>f</B>actor involved in the regulation of rice <B>s</B>eed <B>m</B>aturation. <I>OsSMF1</I> (previously called <I>RISBZ1 or OsbZIP58</I>) is known to interact with GCN4 motifs (TGA(G/C)TCA) to regulate seed storage protein synthesis, and it functions as a key regulator of starch synthesis. Quadruple 9-mer-based PBM analysis and electrophoretic mobility shift assay revealed that OsSMF1 bound to the GCN4 (TGA(G/C)TCA), ACGT (CCACGT(C/G)), and ATGA (GGATGAC) motifs with three different affinities. We predicted 44 putative OsSMF1 target genes using data obtained from both the PBM and RiceArrayNet. Among these putative target genes, 18, 21, and 13 genes contained GCN4, ACGT, and ATGA motifs within their 1-kb promoter regions, respectively. Among them, six genes encoding major grain filling proteins and transcription factors were chosen to confirm the activation of their expression in vivo. OsSMF1 was shown to bind directly to the promoters of Os03g0168500 (GCN4 motif), patatin-like gene (GCN4 motif), α-globulin (ACGT motif), rice prolamin box-binding factor (RPBF) (ATGA motif), and ONAC024 (GCN4 and ACGT motifs) and to regulate their expression.</P><P><B>Conclusions</B></P><P>The results of this study suggest that <I>OsSMF1</I> is one of the key transcription factors that functions in a wide range of seed developmental processes with different specific binding affinities for the three DNA-binding motifs.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (doi:10.1186/s12284-017-0155-4) contains supplementary material, which is available to authorized users.</P>
Joung Sug Kim,Songhwa Chae,Kyong-Mi Jun,Yoon Mok Pahk,Yeon-Ki Kim,Baek-hie Nahm 한국육종학회 2015 한국육종학회 심포지엄 Vol.2015 No.07
Rice, as a model system of monocotyledon plants for genomic studies, is a main staple food for over half of the world population. A rice retrotransposon, Tos17, is active during tissue culture and its ability was wildly used in insertional mutagenesis. In this study we have produced 2,000 non-GM mutants induced by Tos17 in rice. We analyzed >2,000 flanking sequences of newly transposed Tos17 copies by the adaptor-ligation PCR method. The frequencies of Tos17 insertions in the genic and intergenic regions were 60.3% and 36.6%, respectively. We also selected four Tos17 insertion mutant lines for three TF genes which can be considered to be considered to be involved in rice seed development based on expression microarray data: osrem3, osta1, osbhlh1-1, and osbhlh1-2 mutant lines. According to Quadruple 9-mer-based protein binding microarray (Q9-UPBM) experiment, we found that the OsREM3, OsTA1, and OsbHLH1 bound to the ACACCAC, CACGTG, and GTAACA motifs, respectively. In combination of Q9-UPBM, RiceArrayNet analysis, and expression microarray data, we identified 8, 20, and 9 putative target genes of OsREM3, OsTA1, and OsbHLH1, respectively. We have been screening and characterizing the mutations by extensive phenotypic analysis as well as the functional analysis of genes.
Joung Sug Kim,Song Hwa Chae,YoungJin Woo,Min Sun Kim,Kyong Mi Jun,Yoo-Mok Pahk,Yeon-Ki Kim,Baek Hie Nahm 한국육종학회 2014 한국육종학회 심포지엄 Vol.2014 No.07
Spatial- and temporal-specific expression patterns are primarily regulated at the transcriptional level by the promoter. Therefore, it is important to determine the binding motifs of transcription factors to understand the networks associated with embryogenesis. Here, we used a protein-binding microarray (PBM) to determine the binding motif of OsSMF1, which is a basic leucine zipper transcription factor that is involved in the regulation of rice seed maturation. OsSMF1 (previously called RISBZ1) is known to interact with GCN4 motifs (TGA(G/C)TCA) to regulate seed storage proteins (SSPs). In addition, OsSMF1 (also known as OsbZIP58) functions as a key regulator of starch synthesis in the rice seed. Quadruple 9-mer-based PBM (Q9-PBM) and electrophoretic mobility shift assay (EMSA) experiments revealed that OsSMF1 binds to the ACGT (CCACGT(C/G)), GCN4 (TGA(G/C)TCA), and GCN4-like (GGATGAC) motifs with Kd values of 0.3353 μM, 0.6458 μM, and 1.117 μM, respectively. We also identified 60 putative OsSMF1 target genes using a combination of data from expression microarrays and RiceArrayNet (RAN) analysis. Of these OsSMF1 target genes, 20, 22, and 17 genes contained ACGT, GCN4, and GCN4-like motifs within the 2-kb promoter region, respectively. In addition to known target genes, we also identified 35 potential OsSMF1 target genes that have not been previously described in immature seeds. We also confirmed that OsSMF1 directly regulates Os03g0168500 (thioredoxin-related protein), RPBF, NAC6, and two hypothetical proteins (Os12g0621600 and Os11g0582400) in vivo. This study suggests that OsSMF1 functions in a wide range of seed development processes with specific binding affinities for three DNA binding motifs
Characterization of the Catalytic Properties of Recombinant Acetohydroxyacid Synthase from Tobacco
Kim, Joung-Mok,Choi, Jung-Do,Kim, Bok-Hwan,Yoon, Moon-Young Korean Chemical Society 2005 Bulletin of the Korean Chemical Society Vol.26 No.2
The nature of the active site of Tobacco acetohydroxyacid synthase (AHAS) in the substrate- and cofactorbinding was studied by kinetics and fluorescence spectroscopy. The substrate saturation curve does not follow Michaelis-Menten kinetics at different temperatures (7, 21 and 37 ${^{\circ}C}$), pH (6.5, 7.5 and 8.5) and buffers (Tris-HCl and MOPS). The concentration of one half of the maximum velocity ($S_{0.5}$) decreased in the following order: pyruvate $\gt$ ThDP $\approx$$Mg^{+2}$ $\gt$ FAD. However, the catalytic efficiency (K$_{cat}/S_{0.5}$) inversely decreased in the following order; FAD $\gt$ $Mg^{+2}$ $\approx$ThDP $\gt$ pyruvate, indicating that the cofactors by in decreasing order; FAD, $Mg^{+2}$, ThDP, affect the catalysis of AHAS. The dissociation constant ($K_d$) of the intrinsic tryptophan fluorescence decreased with the same tendency of the concentration of one half of the maximum velocity ($S_{0.5}$) decreasing order. This data provides evidence that the substrate and cofactor binding natures of the active site, as well as its activation characteristics, resemble those of other ThDP-dependent enzymes.