• Korean Journal of Environmental Agriculture
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• v.41 no.2
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• pp.82-94
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• 2022

BACKGROUND: Spiropidion and its metabolite are tetramic acid insecticide and require the establishment of an official analysis method for the safety management because they are newly registered in Korea. Therefore, this study was to determine the analysis method of residual spiropidion and its metabolite for the five representative agricultural products. METHODS AND RESULTS: Three QuEChERS methods (original, AOAC, and EN method) were applied to optimize the extraction method, and the EN method was finally selected by comparing the recovery test and matrix effect results. Various adsorbent agents were applied to establish the clean up method. As a result, the recovery of spiropidion was reduced when using the dispersive-SPE method with MgSO₄, primary secondary amine (PSA), graphitized carbon black (GCB) and octadecyl (C₁₈) in soybean. Color interference was minimized by selecting the case including GCB and C18 in addition to MgSO₄. This method was established as the final analysis method. LC-MS/MS was used for the analysis by considering the selectivity and sensitivity of the target pesticide and the analysis was performed in MRM mode. The results of the recovery test using the established analysis method and inter laboratory validation showed a valid range of 79.4-108.4%, with relative standard deviation and coefficient of variation were less than 7.2% and 14.4%, respectively. CONCLUSION(S): Spiropidion and its metabolite could be analyzed with a modified QuEChERS method, and the established method would be widely available to ensure the safety of residual insecticides in Korea.

• KSBB Journal
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• v.15 no.5
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• pp.507-513
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• 2000

The biosynthesis of lovastatin, a cholesterol lowering agent formed by the filamentous fungus Aspergillus terreus, was examined in a 2.5 L jar fermenter. In batch bioreactor cultures conducted at various agitation rates, 400 rpm showed the best result in terms of lovastatin production. Notably, the effect of pH on lovastatin biosynthesis was found to be significant: when the pH was controlled at around 5.8 during the whole fermentation period, lovastatin concentration reached 598 mg/L, which is much hihger than the amounts obtained by pH-uncontrolled and pH 7.4-controlled fermentations. In addition, both L-histidine and L-tryptophan were observed to be favorable amino acids for the enhancement of lovastatin production when 6 g/L of the respective amino acids were supplemented at the beginning of the fermentation period. By further optimization of the production media and the physical environment, lovastatin production was increased to 836 mg/L (3.5 mg/L/hr) which is approximately 10 times higher than the productivity of the basic control culture.

• Journal of Microbiology and Biotechnology
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• v.33 no.6
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• pp.806-822
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• 2023

In the current study we assessed a new crystallized compound, 5-(1-hydroxybutyl)-4-methoxy-3-methyl-2H-pyran-2-one (C-HMMP), from the endophytic fungus Colletotrichum acutatum residing in the medicinal plant Angelica sinensis for its in vitro antimicrobial, antibiofilm, antioxidant, antimalarial, and anti-proliferative properties. The promising compound was identified as C-HMMP through antimicrobial-guided fraction. The structure of C-HMMP was unambiguously confirmed by 2D NMR and HIRS spectroscopic analysis. Antimicrobial property testing of C-HMMP showed it to be effective against a variety of pathogenic bacteria and fungi with MICs ranging from 3.9 to 31.25 ㎍/ml. The compound displayed excellent antibiofilm activity against C. albicans, S. aureus, and K. pneumonia. Furthermore, the antimalarial and radical scavenging activities of C-HMMP were clearly dosedependent, with IC50 values of 0.15 and 131.2 ㎍/ml. The anti-proliferative activity of C-HMMP against the HepG-2, HeLa, and MCF-7 cell lines in vitro was investigated by MTT assay, revealing notable anti-proliferative activity with IC50 values of 114.1, 90, and 133.6 ㎍/ml, respectively. Moreover, CHMMP successfully targets topoisomerase I and demonstrated beneficial anti-mutagenicity in the Ames test against the reactive carcinogenic mutagen, 2-aminofluorene (2-AF). Finally, the compound inhibited the activity of α-glucosidase and α-amylase with IC50 values of 144.7 and 118.6 ㎍/ml, respectively. To the best of our knowledge, the identified compound C-HMMP was obtained for the first time from C. acutatum of A. sinensis, and this study demonstrated that C-HMMP has relevant biological significance and could provide better therapeutic targets against disease.

• ALGAE
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• v.29 no.4
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• pp.333-341
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• 2014

In this study, four compounds isolated from the red alga Laurencia snackeyi were evaluated for their potential anti-inflammatory effect in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. These compounds were tested for their inhibitory effects on nitric oxide (NO) production in LPS-stimulated RAW 264.7 cells. Since $5{\beta}$-hydroxypalisadin B showed the best activity it was further tested for the production of prostaglandin-$E_2$ ($PGE_2$), expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), the release of pro-inflammatory cytokines tumor necrotic factor-alpha (TNF-${\alpha}$), interleukin-$1{\beta}$ (IL-$1{\beta}$), and interleukin-6 (IL-6). $5{\beta}$-Hydroxypalisadin B significantly reduced the $PGE_2$ release and suppressed the iNOS and COX-2 expression in LPS-stimulated RAW 264.7 cells. It also significantly reduced the release of pro-inflammatory cytokines TNF-${\alpha}$, IL-$1{\beta}$, and IL-6. These findings provide the first evidence of anti-inflammatory potential of $5{\beta}$-hydroxypalisadin B isolated from the red alga L. snackeyi and hence, it could be exploited as an active ingredient in pharmaceutical, nutraceutical and functional food applications.

• Korean Journal of Plant Tissue Culture
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• v.28 no.6
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• pp.347-351
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• 2001

Panax ginseng C.A. Meyer is a well-known Korean traditional medicine. Until now, even though major research of ginseng has been focused on the pharmacological effect, clinical application and chemical analysis of extracted secondary metabolite for several years, the physiology and gene functions of ginseng were not well known. In this research, we have developed the protein extraction methods of ginseng root and hairy root for proteome analysis in order to elucidate the gene(s) function of ginseng. Using the liquid nitrogen (equation omitted) TCA method as protein extraction method, about 660 protein spots were detected on the 2-DE gel of hairy root. Additionally, comparative analysis result of 2-DEs of ginseng root (equation omitted) hairy root suggested that proteomes of same organism could be changeable according to the culture condition, growth stages and other stimulus.

• Journal of Plant Biotechnology
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• v.46 no.4
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• pp.274-281
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• 2019

Pistacia chinensis Bunge has not only been used as a medicinal plant to treat various illnesses but its young shoots and leaves have also been used as vegetables. In addition, P. chinensis is used as a rootstock for Pistacia vera (pistachio). Here, the transcriptome of P. chinensis was sequenced to enrich genetic resources and identify secondary metabolite biosynthetic pathways using Illumina RNA-seq methods. De novo assembly resulted in 18,524 unigenes with an average length of 873 bp from 19 million RNA-seq reads. A Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation tool assigned KO (KEGG orthology) numbers to 6,553 (36.2%) unigenes, among which 4,061 unigenes were mapped into 391 different metabolic pathways. For terpenoid backbone and carotenoid biosynthesis pathways, 44 and 22 unigenes encode enzymes corresponding to 30 and 16 entries, respectively. Twenty-two unigenes encode proteins for 16 entries of the carotenoid biosynthesis pathway. As for the phenylpropanoid and flavonoid biosynthesis pathways, 63 and 24 unigenes were homologous to 17 and 14 entry proteins, respectively. Mining of simple sequence repeat identified 2,599 simple sequence repeats from P. chinensis unigenes. The results of the present study provide a valuable resource for in-depth studies on comparative and functional genomics to unravel the underlying mechanisms of the medicinal properties of Pistacia L.

• Microbiology and Biotechnology Letters
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• v.32 no.2
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• pp.101-109
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• 2004

In order to enhance the productivity of AVM $B_{la}$ produced by Streptomyces avermitilis as a secondary metabolite, we established a basic protocol necessary for protoplast fusion with high-producing strains as a fusion partner, and then obtained various kinds offusants by adopting a massive strain-development procedure (a miniaturized strain screening system). An alternative fusion method using UV and/or NTG mutation of protoplasts was developed to screen genetic recombinants without specific selectable markers. In this method, the mutants obtained by protoplast fusion after UV and/or NTG treatment (95% death rate) of the respective fusion partner (protoplasts of the respective mutants resistant against L-isoleucine antimetabolites such as O-methylthreonine and/or azaleucine) were regarded as DNA-recombined protoplast fusants. Notably it was demonstrated that most of the protoplast recombinants obtained by the UV mutation method were able to biosynthesize higher amount of AVM $B_{la}$ , reaching almost three times higher level (almost equal to the industrial productivity), compared to the average AVM Bla amount of the parallel mother strains.

• KSBB Journal
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• v.31 no.3
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• pp.158-164
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• 2016

Plant growth promoting (PGP) hormones, which are produced in a small quantity by bacteria, affect in plant growth and development. PGPs play an important role on the crop productivity in agricultural field. In this study, a photosynthetic bacterial strain producing the PGP was isolated from paddy soil. Bacterial isolate was gram negative, rod-shaped and motility positive. From the 16s rRNA gene sequence analysis, the isolate was identified as Rhodobacter capsulatus PS-2. The mass cultivation of R. capsulatus PS-2 was optimized by considering of the carbon, nitrogen and inorganic salt sources. Optimal medium composition was determined as Na-succinate 4.5 g, yeast extract 5 g, $K_2HPO_4$ 1 g, $MgSO_4$ 5 g, per liter. From the result of 500 L fermentation for 2 days using the optimal medium, the viable cells were $8.7{\times}10^9cfu/mL$. R. capsulatus PS-2 strain produced the carotenoid and indole-3-acetic acid (IAA). The carotenoid extraction and quantitative analysis were performed by HCl-assisting method. Total carotenoid contents from R. capsulatus PS-2 culture broth were measured as $7.02{\pm}0.04$ and $6.93{\pm}0.05mg/L$ under photoheterotrophic and chemoheterotrophic conditions, respectively. To measure the productivity of IAA, colorimetric method was employed using Salkowski reagent at optical density 535 nm. The results showed that the highest content of IAA was $197.44{\pm}5.92mg/L$ in the optimal medium supplemented with 0.3% tryptophan.

• Molecules and Cells
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• v.28 no.4
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• pp.331-339
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• 2009

Capsaicin is a very important secondary metabolite that is unique to Capsicum. Capsaicin biosynthesis is regulated developmentally and environmentally in the placenta of hot pepper. To investigate regulation of capsaicin biosynthesis, the promoter (1,537 bp) of pepper capsaicin synthase (CS) was fused to GUS and introduced into Arabidopsis thaliana (Col-0) via Agrobacterium tumefaciens to produce CSPRO::GUS transgenic plants. The CS was specifically expressed in the placenta tissue of immature green fruit. However, the transgenic Arabidopsis showed ectopic GUS expressions in the leaves, flowers and roots, but not in the stems. The CSPRO activity was relatively high under light conditions and was induced by both heat shock and wounding, as CS transcripts were increased by wounding. Exogenous capsaicin caused strong suppression of the CSPRO activity in transgenic Arabidopsis, as demonstrated by suppression of CS expression in the placenta after capsaicin treatment. Furthermore, the differential expression levels of Kas, Pal and pAmt, which are associated with the capsaicinoid biosynthetic pathway, were also suppressed in the placenta by capsaicin treatment. These results support that capsaicin, a feedback inhibitor, plays a pivotal role in regulating gene expression which is involved in the biosynthesis of capsaicinoids.

• Korean Journal of Microbiology
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• v.25 no.3
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• pp.180-183
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• 1987

Stu I, type II restriction endonuclease, has been purified to homogeneity from Streptomyces tubercidicus (ATCC 25502), and its catalytic properties have been studied. For the purification of Stu I endonuclease free of nonspecific nucleases, DEAE-Sephadex (A-50), QAE-Sephadex (A-50) and Heparin-agarose column chromatography have been performed after ammonium sulfate fractionation of the crude extract. The enzyme was further purified by gel filtration using Sephadex G-100 column to obtain homogeneous form of protein. The single polypeptide species of Stu I endonuclease has a subunit molecular weight of 34,000 $\pm$ 1,000 daltons as judged by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Stu I endonuclease requires $Mg^{2+}$ ion for its activity and is maximally active at neutral pH (7.0-8.0) in the absence of NaCl.