• Journal of Microbiology and Biotechnology
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• v.20 no.9
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• pp.1295-1299
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• 2010

Recently, recombinant Streptomyces venezuelae has been established as a heterologous host for microbial production of flavanones and stilbenes, a class of plant-specific polyketides. In the present work, we expanded the applicability of the S. venezuelae system to the production of more diverse plant polyketides including flavones and flavonols. A plasmid with the synthetic codon-optimized flavone synthase I gene from Petroselium crispum was introduced to S. venezuelae DHS2001 bearing a deletion of the native pikromycin polyketide synthase gene, and the resulting strain generated flavones from exogenously fed flavanones. In addition, a recombinant S. venezuelae mutant expressing a codon-optimized flavanone $3{\beta}$-hydroxylase gene from Citrus siensis and a flavonol synthase gene from Citrus unshius also successfully produced flavonols.

• Natural Product Sciences
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• v.21 no.4
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• pp.261-267
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• 2015

Compared to their terrestrial and marine counterparts, little is known about the capacity of freshwater-derived actinomycete bacteria to produce novel secondary metabolites. In the current study, we highlight the disparities that exist between cultivation-independent and -dependent analyses of actinomycete communities from four locations in Lake Michigan sediment. Furthermore, through phylogenetic analysis of strains isolated from these locations, we identified a Streptomyces sp., strain B025, as being distinct from other Streptomyces spp. isolated from sediment. Upon fermentation this strain produced a rare class of eight-membered lactone secondary metabolites, which have been for their antitumor properties. We used spectroscopic and chemical derivitization techniques to characterize octalactin B (1) in addition to its corresponding novel, unnatural degradation product (2).

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.1931-1938
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• 2007

Analyzed are recent advances in design of novel boronared conjugates of synthetic and natural porphyrins and chlorins. These compounds showed high efficacy as cytotoxic agents for tumor cells in culture and as phototoxins in photodynamic therapy of tumor xenografts. Thus, boronated porphyrins and chlorins emerge as promising class of anticancer agents with potentially multiple advantages: the chemotherapeutic drugs alone and photo- and radiosensitizers in binary treatments.

• Journal of Environmental Science International
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• v.23 no.8
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• pp.1507-1512
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• 2014

Recognition of Korean pre-service elementary school teachers concerning the factor for the environmental class was investigated and analyzed by the factorial analysis. Korean pre-service elementary school teachers are aware of the factor of 'participation in environment' as well as the factor of 'environmental knowledge' for the environmental class. Furthermore, they had a very positive attitude about the factor of 'participation in environment'.

• Bulletin of the Korean Chemical Society
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• v.24 no.1
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• pp.11-12
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• 2003

• Journal of the Korean Chemical Society
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• v.59 no.1
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• pp.69-77
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• 2015

The purpose of this study was to examine changes in student writings of claim and evidence after group and class discussions; changes in students' critical thinking; and students' perceptions on an argument-based claim and evidence writing approach. Seventy two grade 11 students from two classes of a high school located in Seoul participated in ten chemistry activities using the argument-based claim and evidence writing approach. Claim scores for 9 topics and evidence scores for 10 topics significantly improved after group discussion. There were also statistically significant differences in claim scores for 7 topics and evidence scores for 10 topics after class discussion. Participant students responded to an open-ended survey that group discussion helped them to figure out the problem context and class discussion guided them to provide with more sufficient evidence. There were also statistically significant increases in sub-scores of the Cornell Critical Thinking Test after the intervention.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.3
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• pp.242-250
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• 2016

Veterinary antibiotics (VAs) has been used to treat animal disease and to increase animal weight as growth promoter. However, abused usage of VAs can cause production of antibiotic resistance genes (ARGs) in the environment and additionally, residual of VAs in soil can be transferred into crops. Therefore, main objective of this research was to examine bioaccumulation of VAs in sprouts (red cabbage, Brassica Olearacea L. var. Capitata f. rubra and red radish, Raphanus sativus) with hydroponic method. Total of 7 VAs in 2 different classes of VAs (tetracyclcines: tetracycline, oxytetracycline, chlortetracycline, sulfonamides: sulfamethoxazole, sulfamethazine, sulfamethiazole, macrolides: tylosin) were evaluated and experiment was conducted with solid phase extraction (SPE)/high performance liquid chromatography tandem mass spectrometry (HPLC/MS/MS). Initial spiked concentration of 7 VAs was $5mg\;L^{-1}$ and cultivation period was 8 days. Result showed that growth of sprouts was inhibited about 23-27% when VAs was introduced. Amount of bioaccumulated VAs was also differed depending on class of VAs. The highest amount of bioaccmulated VAs was tetracycline and sulfamethoxazole in each class with a concentration of 4.05, $7.73mg\;kg^{-1}$ respectively. Calculated transfer ratio of VAs into crops was also ranged 0.38-54.27%. Overall, bioaccumulation of VAs in crops can be varied depending on crop species and class of VAs. However, further research should be conducted to verify bioaccumulation of VAs in crops in the soil environment.

• The Korean Journal of Food And Nutrition
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• v.2 no.1
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• pp.61-72
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• 1989

This study was conducted to gather the baseline data on realities of experimental-practice and opinions toward spot-practice, and to examine how to cope with the problems raised at the Department of Food and Nutrition of Junior Technical College in Korea. Questionnaires were gathered from 42 chairmans of the Department of Food and Nutrition and 140 Present dieticians worked in Seoul, Bucheon am Seongnam area. The results are as follows, First, as a whole, each college had 2~3 experimental laboratory (Lab), in which Cooking Science Lab. Chemistry Lab and Microbiology Lab were occurred at higher frequency as Lab's name. Second, the numbers per experimental-practice class were more than 40 at most colleges. 85% of Present dieticians have answered to feel too much numbers per the class during their college days, whereas professors' opinions toward the numbers per class were suitable at 20~30 persons per class. Third, professors' opinion toward the adquate ratio of the theory subject classes to experimental subject classes was suitable at 60 : 40. Dieticians answered to take the theory subject classes partly or mostly on behalf of the experimental-practice classes. Fourth, the main reasons which inhibited normal experimental-practice class were the class for emphasis on examination, the shortage of experiment budget, the excess of class members, the shortage of experimental Lab Also, this results showed same propensity to present dieticians' opinion toward the same question above. Fifth, among the experimenta1-practice subjects established at the Department of Food and Nutrition, Diet Therapy Lab was highest frequency class emphasized on theory followed by Nutrition Counselling Lab, Food Processing and Storage Lab, Food Hygiene Lab and Food Microbiology Lab in that order. Here, Basic Chemistry Lab, Biochemistry Lab, Food Microbiology Lab were pointed as subjects far from the present task of dieticians. Sixth, Department of Food and Nutrition, as a whole, has conferred with spot-practice arrangement About 50% (all who want to join spot-practice) of second year students took part in spot-practice. In the other way, all colleges except for 2 colleges didn't give the credit for the spot-practice system. Seventh, according to the on analysis on spot-practice places, manufacturing company was at highest frequcney followed by hospitals, elementary school having group feeding system in that order. Especially, 16.7% (5 colleges) of the total colleges sent the students to the research institute related to food industry for spot-practice experience. Eighth, Professors' opinions toward the spot-practice time and period were preferable on summer vacation of second year and for 1~2 weeks, respectively. On the contrary, 74 dieticians answered to the adquate period as for 4 weeks. Ninth, 86 dieticians of the total 140 answered to complete the spot-practice during their college days, which helps the present task of them. Lacks of spot-practice program, Lacks of comprehension of upper personals and lacks of group feeding equipments ranks higher as difficulties in spot-practice management.

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.2003-2010
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• 2010

A new class of halobenzyloxy or alkoxy 1,2,4-triazoles and their hydrochlorides were synthesized through cyclization starting from commercially available phenylhydrazine. The structures were characterized by MS, IR and $^1H$ NMR spectra as well as elemental analyses. All the synthesized compounds were screened for their antibacterial activities in vitro against Staphylococcus aureus (ATCC29213), methicillin-resistant Staphylococcus aureus (N315), Bacillus subtilis, Escherichia coli (ATCC25922), Pseudomonas aeruginosa, Shigella dysenteriae, Eberthella typhosa, and antifungal activities against Candida albicans (ATCC76615), Aspergillus fumigatus by broth microdilution assay method. The results of preliminary bioassay indicated that 3-(2,4-difluorobenzyloxy)-1-phenyl-1H-1,2,4-triazole hydrochloride exhibited the best inhibitory activity with an MIC value of 56.25 ${\mu}M$ against P. aeruginosa superior to Chloramphenicol, and showed comparable activity with Chloramphenicol against E. coli (ATCC25922).

• Bulletin of the Korean Chemical Society
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• v.10 no.5
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• pp.411-414
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• 1989

A new sensitive fluorimetric method for the determination of N-methylcarbamates, a class of well known insecticides, based on the derivatization with 7-chloro-4-nitrosobenz-2-oxa-1,3-diazole (NBD-Cl) has been developed. Unreacted NBD-Cl was eluted ahead of derivatized carbamates from C-18 bonded column. An argon ion laser was used as an excitation source of chromatographic eluents and its fluorescence signal was monitored with optical multichannel analyzer. The detection limits of various carbamates were about 100 pg range and the working curves were linear to $10^4-10^5$ nanogram ranges.