• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.71.1-71.1
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• 2012

We have identified local analogs of strong $H{\alpha}$ Emitters (HAEs) that dominate the z~4 Lyman-break galaxy population using the Sloan Digital Sky Survey (SDSS). At z<0.4, only 0.04% of galaxies are classified as HAEs with $H{\alpha}$ equivalent width larger than $500{\AA}$, comparable to that of z~4 HAEs. The $H{\alpha}$-to-UV luminosity ratio of local HAEs is consistent with that of z~4 HAEs, indicating relatively large specific star formation rate in these galaxies compared to traditionally studied UV-selected Lyman break analogs. Local HAEs are young, less evolved galaxies with low metallicity. It is still difficult to constrain whether the star formation in local HAEs is powered by minor mergers or by cosmological cold gas accretion. However, the stacked optical spectrum of local HAEs shows several strong ionization lines, for example HeII 4686 emission line, which are shown in Wolf-Rayet galaxies. Thus it is highly likely that local HAEs are galaxies with an elevated ionization parameter, either due to a high electron density or large escape fraction of hydrogen ionizing photons.

• Journal of the Korean Chemical Society
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• v.19 no.2
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• pp.130-133
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• 1975

The 4'-thio analogs of the 5-bromo-and 5-iodo-pyrimidine nucleosides were prepared by condensation of 2,3,5-tri-O-acetyl-4-thio-${\alpha},{\beta}$-D-ribofuranosyl chloride with the chloromercury derivatives of 5-halogeno-2,4-bis(trimethylsiloxy)pyrimidine, followed by the removal of the protecting groups. Although the biological activities of the 4'-thio derivatives are not greatly different from the corresponding 4'-oxygen analogs in this preliminary test, the fact that the 4'-thio analogs have comparableihigh activities, is of interest, and indicates the value of further biochemical examinations.

• Journal of Microbiology
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• v.40 no.2
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• pp.134-139
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• 2002

Effects of GTP on the inhibition of self-splicing of primary transcripts of the phage T4 thymidylate synthase gene (td) by thiamine pyrophosphate and its analogs have been investigated. The order of the inhibitory efficiency for compounds tested was as follows: thiamine pyrophosphate > thiamine monophosphate > thiamine. of all compounds examined, thiamine pyrophosphate was the most potent inhibitor, Increasing GTP concentration in splicing reaction tended to overcome the suppressive effects of self-splicing by thiamine pyrophosphate and its analogs. The inhibition by thiamine pyrophosphate was most sensitized to a higher concentration of GTP, It has been speculated that the key structural features in thiamine pyrophosphate and its analogs responsible for the inhibition of splicing may be a thiamine moiety in which the phosphorylation of 2-hydroxylethyl group on 5-position of thiazolium ring rendered further stimulation of inhibition in self-splicing reaction..

• Journal of Microbiology and Biotechnology
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• v.29 no.1
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• pp.59-65
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• 2019

Fusaricidin analogs, produced by Paenibacillus polymyxa, were tested for selective control of a major bloom-forming cyanobacterium, Microcystis sp. Fusaricidin (A and B mixtures) and four analogs were isolated from P. polymyxa E681 and investigated for their inhibition of cyanobacterial cell growth. Among the four fusaricidin analogs, fraction 915 Da (designated as Fus901) showed growth inhibition activity for Microcystis aeruginosa but not for Anabaena variabilis and Scenedesmus acutus. Microcystin concentration decreased up to 70% and its content per cell also decreased over 50% after 3 days. Fusaricidin exhibited growth inhibition against Gram-positive bacteria but Fus901 did not. Molecular weights of fusaricidin A and B were 883 Da and 897 Da, whereas that of Fus901 was 915 Da. Structure analysis by a ring-opening method revealed a linear form for Fus901. Expression of the pod gene related to oxidative stress was increased 2.1-fold by Fus901 and that of mcyD decreased up to 40%. These results indicate that Fus901 exerts oxidative stress against M. aeruginosa. Thus, Fus901 can be used as a selective cyanobactericide without disturbing the ecological system and could help in decreasing the microcystin concentration.

• Food Science of Animal Resources
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• v.43 no.5
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• pp.889-900
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• 2023

In this study, concentration levels of beet powder (BP) and caramel color (CC) were optimized to simulate beef color in meat analogs before and after cooking. The central composite design of response surface methodology (RSM) was used to set the levels of BP and CC, and the CIE L^*, CIE a^*, and CIE b^* were selected as the responses for RSM. After optimization, myoglobin-free beef patties were prepared with three optimized levels of BP and CC. When raw, all the patties had the same color as natural beef; however, CIE L^*, CIE a^*, and CIE b^* were statistically different from those of beef after cooking (p<0.05). Moreover, the use of BP and CC induced "browning" after the cooking process, with no excessive yellow color. Therefore, based on the overall desirability in the color optimization using RSM, the combination of BP (1.32%) and CC (1.08%) with the highest overall desirability can be used to simulate the color change of beef in meat analogs.

• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.111-115
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• 2015

Two new analogs of bestatin were prepared from $\small{D}$-leucine and $\small{D}$-valine in a stereoselective and efficient way. An aminopeptidase inhibitor bestatin shows significant biological effects on immunomodulation and is marketed for the treatment of acute myelocytic leukemia. The key intermediates, trans-oxazolidine methyl esters 2a and 2b, were obtained with more than 20 to 1 stereoselectivity in a one-pot procedure by the three cascade reactions between N-hydroxymethyl protected ${\alpha}$-amino aldehydes (4a and 4b) and phenylsulfonylnitromethane ($PhSO_2CH_2NO_2$) and the following in-situ ozonolysis. Basic hydrolysis of 2a and 2b, and then the peptide coupling with $\small{L}$-Leu-OMe produced the protected derivatives of two new bestatin analogs, 3a and 3b, respectively. The new isobutyl and isopropyl analogs of bestatin (1a and 1b) were produced in overall 51% and 38% yields, respectively, with high stereoselectivity from the corresponding protected ${\alpha}$-amino aldehydes 4 in a six-step process.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2004.11a
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• pp.35-41
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• 2004

• Bulletin of the Korean Chemical Society
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• v.19 no.10
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• pp.1027-1028
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• 1998

• Bulletin of the Korean Chemical Society
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• v.20 no.12
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• pp.1389-1390
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• 1999

• Proceedings of the PSK Conference
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• 2005.11a
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• pp.93-95
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• 2005