• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.1928-1934
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• 2006

The rubradirin biosynthetic gene cluster harbors 58 ORFs within a 105.6-kb sequence, which includes all of the genes responsible for the synthesis of rubradirin, as well as the primary genes relevant to regulatory, resistance, and transport functions. This gene cluster also harbors a resistance-mediating ABC transporter, RubT1, which is located at the most upstream position in the cluster. In the present study, RubT1 was expressed heterologously in E. coli, and the resistance affinity of RubT1 was determined by an antibacterial activity test, as well as by HPLC and ESI-MS analyses. Evidence clearly demonstrates that RubTl mediates rubradirin resistance as an ABC transporter.

• Food Science and Biotechnology
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• 제18권4호
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• pp.842-848
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• 2009

The purpose of this study was to determine the extent of domoic acid (DA) a potent neurotoxin, responsible for the syndrome amnesic shellfish poisoning (ASP) contamination of various species of bivalve shellfish purchased from fish market in Korea and the implications for food safety. Liquid chromatography (LC) methods were applied to quantify DA in shellfish after sample clean-up using solid-phase extraction (SPE) with strong anion exchange (SAX) cartridges. Toxin detection was achieved using photodiode array ultraviolet (LC-UV) and electrospray ionization-mass (LC-ESI-MS). DA was identified in 4 bivalve shellfishes of 872 shellfishes collected from March, 2006 to October, 2007 in Korea. DA amount of 3 surf clams (Mactra veneriformis) collected at Seoul, Daejeon, and Daegu were 4.13, 1.99, and 1.94 mg/kg, respectively. DA amount of 1 pink butterfly shell (Peronidia venulosa) collected at Seoul was 3.02 mg DA/kg. The amounts of DA that were present in 4 bivalve shellfishes were within EU guideline limits for sale of shellfish (20 mg DA/kg).

• Advances in environmental research
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• 제3권1호
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• pp.29-43
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• 2014

Pharmaceutical wastewater effluents are well known for their difficult elimination by traditional biotreatment methods and their important contribution to environmental pollution due to its fluctuating and recalcitrant nature. OTC is one of the nonbiodegradable antibiotics that makes antibiotic-resistant, so it can make be high risk for environment. NZVI can be a good choice for removal of OTC in aqueous solution. Response surface methodology (RSM) was used to optimize the amounts of NZVI and OTC to be used at pH 3 and under 200 W, UV-A irradiation. The responses were removal percent of absorption at 290 and 348 nm, TOC and COD of OTC. In the optimum condition, Linear model was performed 155 ppm of OTC were removed by 1000 ppm NZVI after 6.5 hours and the removal efficiency of absorption at 290 and 348 nm, TOC and COD were 87, 95, 85 and 89 percent, respectively. In the similar process, there is no organic compound after 14 hours. The parameters ORP, DO and pH were investigated for 6:30 hours to study the type of NZVI reaction in process. In the beginning of reaction, oxidation was the dominant reaction after 3 hours, photocatalytic reaction was remarkable. The mechanism of OTC degradation is proposed by HPLC/ESI-MS and four by products were found. Also the rate constants (first order kinetic chain reaction model) were 0.0099, 0.0021, 0.0010, 0.0049 and $0.0074min^{-1}$, respectively.

• 한국미생물·생명공학회지
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• 제31권2호
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• pp.135-139
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• 2003

Melanin 생합성에 key enzyme인 tyrosinase 억제가 melanin색소 억제에 주된 요인으로 알려져 있지만, 생합성기작에는 여러 다른 요인들이 작용하기 때문에 일차적인 탐색 단계에서 tyrosinase 저해 활성뿐만 아니라 S. bikiniensis의 melanin생합성 억제 연구를 병행하여 천연물을 탐색하였다. 그 중 선택된 궁궁이 (Angelica poiymorpha MAXIM)에서 3가지 물질을 분리하였으며, 3가지 물질 모두가 100$\mu\textrm{g}$/$m\ell$ 이상 농도에서도 tyrosinase억제 활성이 나타나지 않는 반면, S. bikiniensis melanin 생합성 저해 효과를 보여 주었다. 동일 농도에서 S. bikinieffsis의 생장에는 영향을 미치지 않았다.

• Journal of Microbiology and Biotechnology
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• 제24권10호
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• pp.1327-1336
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• 2014

Bacillus amyloliquefaciens strain NJZJSB3 has shown antagonism of several phytopathogens in vitro, especially Sclerotinia sclerotiorum. Both the broth culture and cell suspension of strain NJZJSB3 could completely protect the detached leaves of canola (Brassica napus) from S. sclerotiorum infection. In pot experiments, the application of strain NJZJSB3 cell suspension ($10^8CFU/ml$) decreased the disease incidence by 83.3%, a result similar to commercially available fungicide (Dimetachlone). In order to investigate the potential biocontrol mechanisms of strain NJZJSB3, the nonvolatile antifungal compounds it produces were identified as iturin homologs using HPLC-ESI-MS. Antifungal volatile organic compounds were identified by gas chromatography-mass spectrometry. The detected volatiles toluene, phenol, and benzothiazole showed antifungal effects against S. sclerotiorum in chemical control experiments. Strain NJZJSB3 also produced biofilm, siderophores and cell-wall-degrading enzymes (protease and ${\beta}$-1,3-glucanase). These results suggest that strain NJZJSB3 can be a tremendous potential agent for the biological control of sclerotinia stem rot.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2315-2321
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• 2010

Twenty spirodiclofen analogues have been designed and conveniently synthesized via three steps including esterification, one-pot heterocyclization, and acylation reactions. The target molecules have been identified on the basis of analytical spectra ($^1H$ NMR, $^{13}C$ NMR and ESI-MS) data. All newly synthesized compounds have been screened for their potential insecticidal and herbicidal activity by standard method. The preliminary assays indicated that some of analogues displayed moderate to good insecticidal activity against Plutella xylostella compared with spirodiclofen, and some compounds showed obvious activity against Brassica chinensis. Structure-activity relationship (SAR) is also discussed based on the experimental data.

• Parasites, Hosts and Diseases
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• 제45권3호
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• pp.229-232
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• 2007

The WD40-repeat proteins serve as a platform coordinating partner proteins and are involved in a range of regulatory cellular functions. A WD40-repeat protein (CsWD1) of Clonorchis sinensis previously cloned is expressed stage-specifically in the tegumental syncytium of C. sinensis metacercariae. In the present study, interact-ing proteins with the CsWD1 protein was purified by immunoprecipitation and 2 dimension gel electrophoresis from the C. sinensis metacercaria soluble extract, and tryptic peptides were analyzed by LC/ESI-MS. Putative partner proteins were annotated to be actin-2, glyceraldehyde-3-phosphate dehydrogenase, and hypothetical and unmanned proteins. The CsWD1 protein was predicted to contain 3 conserved actin-interacting residues on its functional surface. With these results, the CsWD1 protein is suggested to be an actin-interacting protein of C. sinensis.

• 한국수산과학회지
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• 제44권5호
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• pp.456-463
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• 2011

We attempted to isolate a collagenase-1 inhibitory peptide from skate Dipturus chilensis skin protein. The protein from skate skin was digested by various enzymes (alcalase, ${\alpha}$-chymotrypsin, neutrase, papain, pepsin, and trypsin) to produce a collagenase-1 inhibitory peptide. The collagenase-1 inhibitory activity of the peptides obtained was measured by gelatin digestion assay. Among the six hydrolysates, pepsin hydrolysate exhibited the highest collagenase-1 inhibitory activity. The peptide showing strong collagenase-1 inhibitory activity was purified by Sephadex G-25 gel chromatography and HPLC using an octadecylsilyls (ODS) column. The amino acid sequence of purified collagenase-1 inhibitory peptide was identified to be Asn-Leu-Asp-Val -Leu-Glu-Val-Phe (961 Da) by quadrupole time of flight (Q-TOF) and electrospray ionization mass spectrometry (ESI-MS) mass spectroscopy. The $IC_{50}$ value of purified peptide was 87.0 ${\mu}M$. Moreover, the peptide did not exhibit cytotoxic effects on human dermal fibroblast cell lines.

• Journal of Microbiology and Biotechnology
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• 제19권11호
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• pp.1348-1354
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• 2009

Bioconversion of the isoflavonoid genistein to 2'-hydroxygenistein (2'-HG) was performed using isoflavone 2'-hydroxylase (CYP81E1) heterologously expressed in yeast. A monohydroxylated product was analyzed by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) and NMR spectrometry and was identified as 2'-HG. An initial bioconversion rate of 6% was increased up to 14% under optimized conditions. After recovery, the biological activity of 2'-HG was evaluated. Bioconverted 2'-HG showed higher antioxidant activity against 1,1-diphenyl-2-picryl hydrazine (DPPH) and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radicals than did genistein. Furthermore, 2'-HG exhibited greater antiproliferative effects in MCF-7 human breast cancer cells than did genistein. These results suggest that 2'-hydroxylation of genistein enhanced its antioxidant activity and cell cytotoxicity in MCF-7 human breast cancer cells.

• 한국식품조리과학회지
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• 제30권5호
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• pp.573-578
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• 2014

The objective of this study was to investigate the antioxidant activities and anthocyanin profiles in the anthocyanin rich fraction (ARFAM) of Aronia melanocarpa, which are considered functional substances and are available as food coloring agents in Korea. Anthocyanins were identified by reversed-phase C18 column chromatography and HPLC-DAD-ESI/MS analysis. The antioxidative activity of the acidic ethanol extract (AME) and the anthocyanin-rich fraction (ARFAM) was determined by scavenging of the diphenylpicrylhydrazyl (DPPH) radical, the hydroxy radical, and the superoxide anion in addition to reducing power using a commercial antioxidant as a reference.