• Journal of Microbiology and Biotechnology
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• v.27 no.7
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• pp.1249-1256
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• 2017

In our search for new sources of bioactive secondary metabolites from Streptomyces sp., the ethyl acetate extracts from endophytic Streptomyces SUK 25 afforded five active diketopiperazine (DKP) compounds. The aim of this study was to characterize the bioactive compounds isolated from endophytic Streptomyces SUK 25 and evaluate their bioactivity against multiple drug resistance (MDR) bacteria such as Enterococcus raffinosus, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter spp., and their cytotoxic activities against the human hepatoma (HepaRG) cell line. The production of secondary metabolites by this strain was optimized through Thornton's medium. Isolation, purification, and identification of the bioactive compounds were carried out using high-performance liquid chromatography, high-resolution mass liquid chromatography-mass spectrometry, Fourier transform infrared spectroscopy, and nuclear magnetic resonance, and cryopreserved HepaRG cells were selected to test the cytotoxicity. The results showed that endophytic Streptomyces SUK 25 produces four active DKP compounds and an acetamide derivative, which were elucidated as $cyclo-({\text\tiny{L}}-Val-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Leu-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Phe-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Val-{\text\tiny{L}}-Phe)$, and N-(7-hydroxy-6-methyl-octyl)-acetamide. These active compounds exhibited activity against methicillin-resistant S. aureus ATCC 43300 and Enterococcus raffinosus, with low toxicity against human hepatoma HepaRG cells. Endophytic Streptomyces SUK 25 has the ability to produce DKP derivatives biologically active against some MDR bacteria with relatively low toxicity against HepaRG cells line.

• Journal of the Korean Chemical Society
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• v.57 no.6
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• pp.744-754
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• 2013

Quantitative structure-activity relationship (QSAR) analysis for recently synthesized imidazole-(benz)azole and imidazole - piperazine derivatives was studied for their anticancer activities against breast (MCF-7) cell lines. The statistically significant 2D-QSAR models ($r^2=0.8901$; $q^2=0.8130$; F test = 36.4635; $r^2$ se = 0.1696; $q^2$ se = 0.12212; pred_$r^2=0.4229$; pred_$r^2$ se = 0.4606 and $r^2=0.8763$; $q^2=0.7617$; F test = 31.8737; $r^2$ se = 0.1951; $q^2$ se = 0.2708; pred_$r^2=0.4386$; pred_$r^2$ se = 0.3950) were developed using molecular design suite (VLifeMDS 4.2). The study was performed with 18 compounds (data set) using random selection and manual selection methods used for the division of the data set into training and test set. Multiple linear regression (MLR) methodology with stepwise (SW) forward-backward variable selection method was used for building the QSAR models. The results of the 2D-QSAR models were further compared with 3D-QSAR models generated by kNN-MFA, (k-Nearest Neighbor Molecular Field Analysis) investigating the substitutional requirements for the favorable anticancer activity. The results derived may be useful in further designing novel imidazole-(benz)azole and imidazole-piperazine derivatives against breast (MCF-7) cell lines prior to synthesis.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.200-207
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• 1987

This study was conducted to select and develop herbicide resistant plant through tissue culture. Growth response of seedlings and callis of various rice varieties with Echinochloa species was assessed under the treatment of various rates of butachlor [N-(butoxy methyl)-2-chloro-2', 6'-diethyl acetamide] and simetryne [2,4-bis(ethyl amino)-6-methyl thio-1,3,5-triazine]. Further, succinate dehydrogenase activity was determined in herbicide treated callus to characterize different response of plants to herbicide. Rice variety like Sangpung showed relative resistance in both callus and seedling states against butachlor, indicating maintenance of resistance. However, in the simetryne treatment, the similar response was not observed in callus and seedling state, although there was a great different response among plant materials against simetryne. Rice variety which exhibited resistance in callus and seedling states showed low succinate dehydrogenase inhibition index. Succinate dehydrogenase inhibition index can be used as an important marker characters to differentiate varietal response of plant to herbicide. Rice plant was differentiated from butachlor and simetryne tolerant callus treated at $2.5{\times}10^{-5}$ M is growing under the growth chamber and can be used for resistant source.

• Korean Journal of Weed Science
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• v.10 no.4
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• pp.277-284
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• 1990

The response of rice (Oryza sativa L.) cultivars to mixtures of 2, 4-D(2, 4-dichlorophenoxyacetic acid) and other herbicides was investigated to determine if there was an interaction between them. When 2, 4-D was applied, shoot growth of Taipei 309 was more affected than that of IR28 at all concentrations used. In contrast, when thiobencarb (S-[(4-chlorophenyl)methyl]diethylcarbamothioate), butachlor [N-(buthoxymethyl) -2-chloro-N-(2, 6-diethylphenyl) acetamide], and glyphosate [N-(phosphonomethyl)glycine] were applied, the shoot growth of Taipei 309 was less affected than that of IR28 at all herbicide concentrations. Combination of 2, 4-D and the lowest thiobencarb concentration was antagonistic for shoot length for both cultivars, but at higher concentrations, it was synergistic. Synergism for shoot fresh weight between 2, 4-D and thiobencarb was observed with IR28 at all concentrations but, for Taipei 309, synergism was observed only at lower 2, 4-D concentrations. Mixing 2. 4-D with butachlor resulted in greater inhibition in shoot length and fresh weight of IR28 than Taipei 309 at all concentrations indicating a synergistic interaction. With combinations of 2, 4-D and glyphosate, an antagonistic interaction for shoot length was observed for both cultivars. A synergistic interaction for shoot fresh weight was observed with IR28 when combinations of the highest concentration of glyphosate and 2, 4-D were applied but there was an antagonistic interaction with Taipei 309.

• Polymer(Korea)
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• v.29 no.5
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• pp.433-439
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• 2005

The copolymers were prepared by the emulsion copolymerization of fluoroalky lacrylate-stearylacrylate-m-isopropenyl-${\alpha},\;{\alpha}'$-dimethylbenzyl isocyanate (TMI) in order to obtain water repellent polymers. The respective copolymerization rates of the three monomers considerably depended upon the use of the nonionic emulsifier and the nonionic-cationic mixed emusifier, and the optimum conditions were obtained. The particle sizes of the copolymers were in the range of 105 to 222nm. The particle sizes of the copolymers prepared by the use of the mixed emulsifiers were smaller than those of the copolymers prepared by the use of the nonionic emulsifier. The reactions of both TMI-N-methyl acetamide and TMI-cellobiose did not take place. However, the reaction of TMI-n-butylamine occurred. The water contact angles before and after washing three times for nylon and poly(ethylene terephthalate) (PET) fabrics coated with the copolymer prepared by the use of mixed emulsifier were about $139^{\circ}\;and\;133^{\circ}$ Therefore, the copolymer showed good durable repellency for nylon and PET.

• Korean Journal of Weed Science
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• v.10 no.4
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• pp.285-293
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• 1990

The response of callus growth of rice (Oryza sativa L.) cultivars which showed different responses to herbicides as seedlings was investigated to select resistant or tolerant calli. Callus growth of IR28 which was susceptible to thiobencarb (S-[(4-chlorophenyl)methyl]diethylcarbamothioate) during callus induction was not inhibited by $10^{-5}$ M and $10^{-6}$ M thiobencarb, indicating that there was a difference in tolerance among callus induction and growth, and the intact plant level. A similar result was obtained with IR31917-45-3-2-2 to butachlor [N - (buthoxymethyl) -2-chloro-N- (2, 6-diethylphenyl) acetamide]. The fresh weight of IR28 callus transferred into $10^{-5}$ M thiobencarb after treatment at $10^{-6}$ M for 30 days was not affected by the herbicide, indicating that transferring callus into gradually higher herbicide concentrations can be a useful method for selection of herbicide-tolerant cell lines.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.19-29
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• 1995

The effect of seeding depth on the growth, mesocotyl elongation and herbicidal response of rice(Oryza sativa L., Japonica type, cv. "Tongjin") and barnyardgrass(Echinochloa crus-galli Beauv. var orizicola Ohwi.) were studied in greenhouse experiments. Barnyardgrass growth as affected by different water depths was briefly tested. Rice and barnyardgrass were broadcast in soil into Oem, 1cm, 2cm and 3cm in seeding depth under dry direct-seeded condition. Butachlor(N-(buthoxymethyl)-2-chloro-N-(2,6-diethylphenyl) acetamide) at dose rate of 1800g ai/ha and thiobencarb(S-[(4-chlorophenyl)methyl] diethyl carbamothioate) at dose rate of 2100g and 4200g ai/ha were soil applied to them at 5 days after seeding. At 10 days after seeding, plants harvested to examine their growth as affected by seeding depth. Root length and shoot fresh weight of rice untreated was greatest in 1cm- and 3cm-seeding depth, respectively, however, mesocotyl did not elongate. While plant height of barnyardgrass grew regardless of seeding depth and water depth, but root length was greatest in 1cm-seeding depth of dry condition and reduced with increased water depth. And mesocotyl was elongated in only dry condition and its length increased with increased seeding depth. At 10 days after application thiobencarb applied pre-emergence inhibited plant height, and shoot fresh weight of rice in only 0cm-seeding depth under dry condition whereas was unaffected in above 1cm-seeding depth, similar to untreated control, and ever increased root length and root fresh weight of rice. On the other hand, shoot, root and leaf growth of barnyardgrass was, severely inhibited regardless of application rates and seeding depths. Reduction of shoot growth by treatment of herbicide was significantly greater than that of root growth. Consequently, reduction of barnyardgrass growth by treatment of thiobencarb did not be associated with seeding depth and mesocotyl elongation as affected by different seeding depth.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.53-58
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• 1988

This study was carried out to determine effect of butachlor [N.-(buthoxymethyl)-2-chloro-N-(2,6-diethylphenyl) acetamide] and bialaphos [2-amino-4(hydroxy)(methyl) phosphionyl] butyryl-alanylalanine sodium salt on the germination of tobacco seed, induction and growth of callus from tobacco. Further, fatty acids and ammonia content of tobacco calli were determined. Bialaphos had no effect on tobacco seed germination, but the growth of seedling was markedly affected by an application of 10 ppm bialaphos. However, regardless of varieties tested, tobacco seed germination was completely inhibited by $5{\times}10^{-5}M$ of butachlor. At an application of $5{\times}10^{-5}M$ butachlor, tobacco seeds were to some extent germinated and showed further growth. Hyangcho among varieties tested, showed the most tolerant response to butachlor. In induction of callus from various tobacco varieties and their growth, aromatic type of tobacco varieties exhibited the most tolerance against bialaphos. However, no distinct varietal differences were determined in the treatment of butachlor. The major fatty acids identified in tobacco calli were palmitic, oleic and linoleic acid. No marked difference in terms of fatty acids was observed among tobacco varieties used, but it was observed that there was the higher ratio of quantity in unsaturated fatty acids over saturated one, bialaphos treatment accumulated about 9 times higher ammonia content than that of the untreated control, giving an evidence that bialaphos might inhibit glutamine synthetase activity.