• YAKHAK HOEJI
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• v.38 no.2
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• pp.197-201
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• 1994

A number of 7-[(3-methylthio or methylthiomethyl)pyrrolidiny]qui nolone-3-carboxylic acids were synthesized by condensation of 7-fluoro substituted quinolone-3-carboxylic acid with 3-methylthiopyrrolidine or 3-methylthiomet hylpyrrolidne. 3-Methylthiopyrrolidine or 3-methylthio-methylpyrrolidine which was prepared from N-benzyl-3-hydroxy pyrrolidine or 3-hydroxymethylpyrrolidine. The in vitro antimicrobial activity of them were tested against twenty species of Gram-positive or Gram-negative microorganisms. It showed remarkable antibacterial activity, particularly against Gram-positive microorganisms. Among those 1-cyclopropyl-6,8-difluoro-7-(3-methylthiomethy-lpyrrolidinyl)-1,4-d ihydro-4-oxo-3-quinolinecarboxylic acid(7d) and 1-cyclopropyl-6- fluoro-8-chloro-7-(3-methylthiomethyl pyrrolidinyl)-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid (7f) showed the most potent in vitro antibacterial activity.

• YAKHAK HOEJI
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• v.38 no.3
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• pp.230-237
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• 1994

The structure-activity relationships of (E)-chalcone-4-carboxylic acids, flavone-4'-carboxylic acids, two types of aromatic amides, terephthalic monoanilides, and (arylcarboxamido)benzoic acids, which were made by Shudo group, are discussed by conformation analysis(AM1) of retinoic acid and those compounds. Conformer of each compound is superimposed on the conformationally restricted compound, 4-(6,7,8,9-tetrahydro-6,6,9,9-tetramethyl-4H-4-oxonaphto[ 2,3-b]pyran-2-yl) benzoic acid(Fv80), possessing the strongest differentiation-inducing activity on human promyelocytic leukemia cells HL-60. The results indicated that the lengths between the carboxylic carbon and the two 6, 9 carbons binding to dimethyl, 1.20 nm and 1.09 nm, as well as the planarity of molecule are very important factors for the activity, especially 1.20 nm. In the case of the recently synthesized azulenic retinoic acids by Sato, et al. in 1993, the distance probably is also important, resulted from superimposing them on a Ch55 conformer and Fv80. The distance 1.0 nm is also important in Ch55. Several conformers of all-trans retinoic acid (RA) are well superimposed on the almost non-flexible Fv80, RA, 9-cis RA, and, specifically s-10,12 cis RA. And a simple hexangular model of RA is suggested to draw RA conformers easily without computer drawing model or molecular model.

• YAKHAK HOEJI
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• v.56 no.3
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• pp.186-190
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• 2012

Nuclear factor-${\kappa}B$ (NF-${\kappa}B$) has been considered as one of the major targets for therapeutic agents of diverse human diseases. In the previous studies, 6-hydroxy-7-methoxychroman-2-carboxylic acid N-phenylamide (KL-1156) and chroman-2-carboxylic acid N-(4-chlorophenyl)amide were identified as good inhibitors of NF-${\kappa}B$ activation. In this continuous study, we describe the synthesis and NF-${\kappa}B$ inhibitory activities of chroman derivatives containing N-heteroaryl groups for exploration of SAR (structure-activity relationship). In addition, inhibitory effects of cell proliferation are evaluated against human cancer cell lines (NCI-H23 and PC-3).

• Elastomers and Composites
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• v.48 no.4
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• pp.256-262
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• 2013

We synthesized thermoplastic polyurethane elastomer (TPU) with different contents of sulfuric acid group, and characterized their physical properties such as mechanical, thermal and grip properties. And the results were compared with carboxylic acid-introduced TPU. Wet slip, tensile strength and abrasion properties were increased by the introduction of acid group. Mechanical properties increased with increasing the acid content up to 0.3 wt%. However, wet slip was continually increased as the acid content increased due to increase of hydrophilicity of TPU.

• Membrane Journal
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• v.19 no.2
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• pp.104-112
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• 2009

Ultrafiltration membranes (UF) were manufactured by the conventional phase inversion method using an additives with N-methyl-2-pyrrolidinone as a solvent. Characteristics of performance could be controlled by the preparation conditions and the operating methods. The fouling resistance was observed by the relative ratio of permeate flux $(J_t)$/pure water flux $(J_o)$. Compared with the anion charged membranes and its original polyamide membrane, fouling resistance to the protein was increasing in proportion to the ion exchange capacity. The relative flux for the bovin serum albumin (BSA) solution increased as pH value further away from isoelectric point of BSA. The hydrophilicity of a membrane, the pH condition, and the operating temperature played the important role in the membrane permeations.

• Macromolecular Research
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• v.12 no.4
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• pp.384-390
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• 2004

Single-walled carbon nanotubes (SWNTs) have been chemically modified through the formation of carboxylic acid functionalities or by grafting octadecylamine and polystyrene onto them. We purified SWNTs with nitric acid to remove some remaining catalysts and amorphous carbon materials. After purification, we broke the carbon nanotubes and shortened their lengths by using a 3:1 mixture of concentrated sulfuric acid and nitric acid. During these purification and cutting processes, carboxylic acid units formed at the open ends of the SWNTs. Octa-decylamine and amino-terminated polystyrene were grafted onto the cut SWNTs by condensation reactions between the amine and carboxylic acid units. The cut SWNTs did not disperse in organic solvents, but the octadecylamine-grafted and polystyrene-grafted SWNTs dispersed well in dichloromethane and aromatic solvents (e.g., benzene, toluene). Composites were prepared by mixing polystyrene with the octadecylamine-grafted or polystyrene-grafted SWNTs. Each composite had a higher dynamic storage modulus than that of a pristine polystyrene. The composites exhibited enhanced storage moduli, complex viscosities, and unusual non-terminal behavior when compared with a monodisperse polystyrene matrix because of the good dispersion of carbon nanotubes in the polystyrene matrix.

• YAKHAK HOEJI
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• v.38 no.5
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• pp.520-524
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• 1994

A number of 7-[(3-methylthio or methylthiomethyl)-3-pyrrolinyl] quinolone-3-carboxylic acids were synthesised by condensation of 7-fluoro substituted quinolone-3-carboxylic acid with 3-methylthio-3-pyrroline or 3-methylthiomethyl-3-pyrroline. The in vitro antimicrobial activity of them were tested against twenty species of Gram-positive or Gram-negative microorganisms. It showed remarkable antibacterial activity, particularly against Gram-positive microoganisms. Among those 1-cyclopropyl-6,8-difluoro-7-[(3-methylthiomethyl) -3-pyrrolinyl]-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid(12a) and 1-cycl opropyl-6-fluoro-8-chlore-7-[(3-methylthiomethyl)-3-pyrrolinly]-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid(12b) showed the most potent in vitro antibacterial activity.

• Genes and Genomics
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• v.40 no.11
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• pp.1237-1248
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• 2018

Introduction Cellulose microfibril is a major cell wall polymer that plays an important role in the growth and development of plants. The gene cellulose synthase A (CesA), encoding cellulose synthases, is involved in the synthesis of cellulose microfibrils. However, the regulatory mechanism of CesA gene expression is not well understood, especially during the early developmental stages. Objective To identify factor(s) that regulate the expression of CesA genes and ultimately control seedling growth and development. Methods The presence of cis-elements in the promoter region of the eight CesA genes identified in flax (Linum usitatissimum L. 'Nike') seedlings was verified, and three kinds of ethylene-responsive cis-elements were identified in the promoters. Therefore, the effect of ethylene on the expression of four selected CesA genes classified into Clades 1 and 6 after treatment with $10^{-4}$ and $10^{-3}M$ 1-aminocyclopropane-1-carboxylic acid (ACC) was examined in the hypocotyl of 4-6-day-old flax seedlings. Results ACC-induced ethylene either up- or down-regulated the expression of the CesA genes depending on the clade to which these genes belonged, age of seedlings, part of the hypocotyl, and concentration of ACC. Conclusion Ethylene might be one of the factors regulating the expression of CesA genes in flax seedlings.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.575-579
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• 2013

1,3-Propandiol is a promising chemical which can be produced from fermentation of glycerol because the application of 1,3-propanediol is mainly in the production of bio-polytrimethylene terephthalate (bio-PTT). However, the cost of downstream processes in the biological production of 1,3-propanediol can make a high portion in the total production cost due to the large amount of water and the by-produced carboxylic acids such as succinic, lactic and acetic acids in 1,3-propanediol fermentation broth. In this study, aqueous two-phases systems composed of hydrophilic alcohols and phosphate salts were applied to the recovery of 1,3-propanediol from its artificial aqueous solution. Formation of aqueous biphases in hydrophilic alcohols and phosphate salts was due to the salting-out effect of salts in bottom phase, thereby 1,3-propanediol in bottom phase was moved into top phase. Extraction efficiency for 1,3-propanediol was proportional to the polarity of hydrophilic alcohols and the basicity of salts and the maximum value of extraction efficiency was more than 98%. In the aqueous two-phases systems after extraction, there was no carboxylic acid in top phase. Therefore, it was concluded that the aqueous two-phases systems composed of hydrophilic alcohols and phosphate salts were effective for the selective recovery of 1,3-propanediol without any coextraction of carboxylic acids.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.342-347
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• 2004

A bacterial strain YC4963 with antifungal activity against Colletotrichum orbiculare, a causal organism of cucumber anthracnose was isolated from the rhizosphere soil of Siegesbeckia pubescens Makino in Korea. Based on physiological and biochemical characteristics and 16S ribosomal DNA sequence analysis, the bac­terial strain was identified as Pseudomonas aurantiaca. The bacteria also inhibited mycelial growth of several plant fungal pathogens such as Botrytis cinerea, Fusarium oxysporum and Rhizoctonia solani on PDA and 0.1 TSA media. The antifungal activity was found from the culture filtrate of this isolate and the active compound was quantitatively bound to XAD adsorption resin. The antibiotic compound was purified and identified as phenazine-l-carboxylic acid on the basis of combined spectral and chemical analyses data. This is the first report on the production of phenazine-l-carboxylic acid by Pseudomonas aurantiaca.