• Journal of Life Science
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• v.28 no.3
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• pp.351-356
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• 2018

L-Serine dehydratase (LSD) is an iron-sulfur containing enzyme that catalyzes the conversion of L-serine to pyruvate and ammonia. Among the bacterial amino acid dehydratases, it appears that only the L-serine specific enzymes utilize an iron-sulfur cluster at their catalytic site. Moreover, bacterial LSDs are classified into four types based on structural characteristics and domain arrangement. To date, only the LSD enzymes from a few bacterial strains have been studied, but more detailed investigations are required to understand the catalytic mechanism of various bacterial LSDs. In this study, LSD type II from Mycobacterium tuberculosis (MtLSD) H37Rv was expressed and purified to elucidate the biochemical and catalytic properties using the enzyme kinetic method. The L-serine saturation curve of MtLSD exhibited a typically sigmoid character, indicating an allosteric cooperativity. The values of $K_m$ and $k_{cat}$ were estimated to be $59.35{\pm}1.23mM$ and $18.12{\pm}0.20s^{-1}$, respectively. Moreover, the plot of initial velocity versus D-serine concentration at fixed L-serine concentrations showed a non-linear hyperbola decay shape and exhibited a competitive inhibition for D-serine with an apparent $K_i$ value of $30.46{\pm}5.93mM$ and with no change in the $k_{cat}$ value. These results provide insightful biochemical information regarding the catalytic properties and the substrate specificity of MtLSD.

• Tuberculosis and Respiratory Diseases
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• v.39 no.6
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• pp.517-525
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• 1992

Background: Since its development by Saiki et al, polymerase chain reaction (PCR) has been very useful in various fields of molecular biology. PCR can be used for the detection of a very small amount of microbial agent, and is especially useful in those patients who are difficult to diagnose microbiologically or serologically. Mycobacterium tuberculosis is a very slowly growing organism and AFB staining frequently shows false negative results, and therefore PCR would be a very rapid, easy, and sensitive diagnostic method for the diagnosis of Mycobacterium tuberculosis. Method: To compare PCR with conventional methods in diagnosing Mycobacterium tuberculosis in sputum, we used sputa of patients who visited or were admitted to Seoul National University Hospital. The amplification targets were 383 base pair DNA, a part of 2520 base pair DNA encoding 65 kD Mycobacterium tuberculosis specific protein (the primers are TB-1, -2), and 123 base pair DNA, a part of IS6110 fragment, which multiple copies are known to exsist PCR one genome (the primers are Sal I-1, -2). We also requested AFB staing and culture to the lab of Seoul National University Hospital with the same sample and compared the results. Results: 1) Using TB-1, -2 primers, PCR was positive in 73.1% (19/26) of culture positive sputa, in 12.5% (1/8) of culture negative. but clinically diagnosed tuberculous sputa, and was negative in all sputa of patients who were clinically diagnosed as non-tuberculous etiology. 2) Using Sal I-I, -2 primers, PCR was positive in 94.1% (32/34) of culture positive sputa, in 23.1% (6/26) of culture negative, but clinically diagnosed tuberculous sputa, and was negative in 87.5% (14/16) of sputa from patients who were clinically diagnosed as non-tuberculous etiology. Conclusion: PCR could be a very rapid, sensitive and specific method for the diagnosis of Mycobacterium tuberculosis in sputa, and further studies should be followed for the development of easier method.

• Archives of Pharmacal Research
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• v.27 no.7
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• pp.713-719
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• 2004

Several analogues of the general formulae 2-methoxy-9-substituted acridine and 6-chloro-2-methoxy-9-substituted acridine were synthesized and evaluated in vitro at 6.25 $\mu\textrm{g}$/mL against M. tuberculosis $H_{37}Rv$. Compounds 15 and 17 showed potential antitubercular activity with 100％ inhibition to the virulent mycobacterium.

• The Korean Journal of Food And Nutrition
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• v.30 no.6
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• pp.1348-1358
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• 2017

To enhance the physiological activity of the Rhynchosia volubilis (RV), R. volubilis (RVHE-A) and R. volubilis-added herbal powder (RVHE-B) were fermented with a solid state culture of Hericium erinaceum mycelia (HE). The total isoflavone contents of the non-fermented RV-A ($489.9{\mu}g/g$) and RV-B ($571.1{\mu}g/g$) were remarkably increased in fermented RVHE-A ($1,836.4{\mu}g/g$) and RVHE-B ($1,276.7{\mu}g/g$). In particular, aglycone isoflavones such as daidzein and genistein were significantly higher in the RVHE-A than any other sample. When hot-water (HW) and EtOH extracts (E) were fractionated from the RV and RVHE, both extracts from the RVHE-A were higher than those from the RV-A in total polyphenol and flavonoid contents. However, the RVHE-B-HW showed a lower polyphenol and flavonoid content level than did RV-B-HW. RVHE-A-HW and -E also had more potent ABTS radical scavenging activity than any extract from the non-fermented RV and other ferments (RVHE-B). In the meanwhile, RVHE-A-HW potently stimulated the production of macrophage activation-related cytokines such as $TNF-{\alpha}$, IL-6 and IL-12 ($841.7{\pm}71.3pg/mL$, $3.9{\pm}0.1ng/mL$, $179.3{\pm}30.2pg/mL$) from peritoneal macrophage more than RV-A-HW ($92.5{\pm}1.5pg/mL$, $0.1{\pm}0.0ng/mL$, $37.4{\pm}5.4pg/mL$) as well as RVHE-B-HW ($557.0{\pm}21.3pg/mL$, $1.8{\pm}0.0ng/mL$, $90.0{\pm}10.0pg/mL$). However, all the EtOH extracts did not show significant activity. In addition, the RVHE-A-HW showed a significantly higher intestinal immune system modulating activity through Peyer's patch and GM-CSF production than did any other extract from RV and RVHE-B. In conclusion, these results suggest that the fermented R. volubilis with H. erinaceum mycelia possesses a possible use as an industrial application as functional food or material.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.77.1-77.1
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• 2012

We present high-resolution radial velocity measurements of K2 giant ${\varepsilon}$ CrB from February 2005 to January 2012 using the fiber-fed Bohyunsan Observatory Echelle Spectrograph at Bohyunsan Optical Astronomy Observatory. We find that the RV measurements for ${\varepsilon}$ CrB exhibit a periodic variation of 418 days with a semi-amplitude of 129 m/s. There is no correlation with RV measurements and inhomogeneous surface features by examining chromospheric activity indicator (Ca II H region), the Hipparcos photometry, and bisector velocity span. Thus, Keplerian motion is the most likely explanation, which suggests that the RV variations arise from an orbital motion. Assuming a possible stellar mass of 1.7 $M_{\odot}$, for ${\varepsilon}$ CrB, we obtain a minimum mass for the planetary companion of 6.7 $M_{Jup}$ with an orbital semi-major axis of 1.3 AU, and an eccentricity of 0.11. We support that more massive stars harbor more massive planetary companions in giant hosting planetary companions (Dollinger et al. 2009), as well as, we discuss the frequency of detected planetary companions with the metallicity distribution in giant (Pasquini et al. 2007; Quirrenbach et al. 2011).

• Journal of Microbiology and Biotechnology
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• v.29 no.9
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• pp.1401-1411
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• 2019

Mycobacterial cell walls comprise thick and diverse lipids and glycolipids that act as a permeability barrier to antibiotics or other chemical agents. The use of OH radicals from a non-thermal plasma jet (NTPJ) for the inactivation of mycobacteria in aqueous solution was adopted as a novel approach. Addition of water vapor in a nitrogen plasma jet generated OH radicals, which converted to hydrogen peroxide ($H_2O_2$) that inactivated non-pathogenic Mycobacterium smegmatis and pathogenic Mycobacterium tuberculosis H37Rv. A stable plasma plume was obtained from a nitrogen plasma jet with 1.91 W of power, killing Escherichia coli and mycobacteria effectively, whereas addition of catalase decreased the effects of the former. Mycobacteria were more resistant than E. coli to NTPJ treatment. Plasma treatment enhanced intracellular ROS production and upregulation of genes related to ROS stress responses (thiolrelated oxidoreductases, such as SseA and DoxX, and ferric uptake regulator furA). Morphological changes of M. smegmatis and M. tuberculosis H37Rv were observed after 5 min treatment with $N_2+H_2O$ plasma, but not of pre-incubated sample with catalase. This finding indicates that the bactericidal efficacy of NTPJ is related to the toxicity of OH and $H_2O_2$ radicals in cells. Therefore, our study suggests that NTPJ treatment may effectively control pulmonary infections caused by M. tuberculosis and nontuberculous mycobacteria (NTM) such as M. avium or M. abscessus in water.

• Tuberculosis and Respiratory Diseases
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• v.57 no.1
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• pp.25-31
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• 2004

Background : IFN-${\gamma}$ is the main effector mediator of the host immune response against Mycobacterium tuberculosis. Evaluating the IFN-${\gamma}$ gene expression in response to M. tuberculosis antigens may help in elucidating the host defense mechanism against M. tuberculosis and in the development of a vaccine. Methods : The IFN-${\gamma}$ mRNA expression in the lymphocytes obtained from pleural effusions from tuberculous pleurisy patients (TB-PLC) after in vitro stimulation with whole cell M. tuberculosis(H37Rv), purified protein derivatives(PPD), man-lipoarabinamman (man-LAM), ara-LAM and Antigen 85B(Ag85B) were evaluated. The degree of IFN-${\gamma}$ mRNA expression was determined by a semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) method. Results : M. tuberculosis induced the expression of IFN-${\gamma}$ mRNA in the TB-PLC in time and dose dependent manners. The PPD and Ag85B induced high levels of IFN-${\gamma}$ mRNA expression in the TB-PLC. However, man-LAM inhibited IFN-${\gamma}$ mRNA expression in the TB-PLC, while ara-LAM did not. Conclusion : IFN-${\gamma}$ mRNA expression in TB-PLC is stimulated by PPD and Ag85B, but inhibited by man-LAM.

• The Journal of the Korean Society for Microbiology
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• v.35 no.5_6
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• pp.375-375
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• 2000

• YAKHAK HOEJI
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• v.15 no.3_4
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• pp.93-97
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• 1971

Seventeen novel compounds of thiosemicarbazone derivatives were synthesized and evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H$_{37}$Rv and antibacterial activity against Staphylococcus aureus, Escherichia coli. It was found that 4-($\alpha$-naphthyl)-1-(2-furfuraldehyde)-3-thiosemicarbazone was active at 0.01$\mu$g/ml and 1, 1'-(p-phenylene)-4, 4'-bis(phenyl)-2, 2'-dithiosemicarbazide, at 0.01$\mu$g/ml against E. coli, respectively.

• Korean Journal of Microbiology
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• v.12 no.2
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• pp.85-93
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• 1974

Four stereoisomers of inositol p-aminosalicylate, that is hexaris-O-(p-aminosalicylyl)-myo-inositol, hexaris-O-(p-aminosalicylyl)-muco-inositol were synthesized by p-aminosalicylyl chloride with myo-, epi-, scyllo-, and muco-inositol respectively. Their antibacterial activity was tested against human type tubercle bacilli $H_{37}$/Rv, in contrast to 1.25.gamma./ml of p-aminosalicylic acid used as control. Hexaris-O-(p-aminoslicylyl)-muco-inositol showed the strongest antibacterial action at 0.625.gamma./ml, the other compounds more or less active than p-aminosalicylic acid.