• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.191.1-191
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• 1998

No Abstract, See Full Text

• Environmental Engineering Research
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• v.14 no.4
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• pp.250-254
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• 2009

Contamination of microcystins, a family of heptapeptide hepatotoxins, in eutrophic water bodies is a worldwide problem. Due to their poisoning effects on animals and humans, there is a requirement to characterize and quantify all microcystins present in a sample. As microcystins are, for most part, intracellular toxins produced by some genera of cyanobacteria, lysing cyanobacterial cells to release all microcystins is considered an important step. To date, although many cell lysis methods have been used, little work has been conducted comparing the results of those different methods. In this study, various methods for cell lysis and toxin extraction from the cell lysates were investigated, including sonication, bead beating, freeze/thaw, lyophilization and lysing with TritonX-100 surfactant. It was found that lyophilization, followed by extraction with 75% methanol, was the most effective for extracting toxins from Microcystis aeruginosa cells. Another important step prior to the analysis is removing impurities and concentrating the target analyte. For these purposes, a C18 Sep-Pak solid phase extraction cartridge was used, with the percentage of the eluent methanol also evaluated. As a result, methanol percentages higher than 75% appeared to be the best eluting solvent in terms of microcystin-leucine-arginine (MC-LR) recovery efficiency for the further chromatographic and mass spectrometric analyses.

• Journal of Environmental Science International
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• v.11 no.11
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• pp.1157-1163
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• 2002

The effective removal of microcystins by chlorination was investigated on a laboratory scale. With an initial chl.a concentration of more than 1,000 $\mu\textrm{g}$/ℓ, the required chlorine dose for the effective removal of microcystins from the raw water was more than 8.0 mg/ℓ. Whereas, a chlorine dose of 3.0 mg/ℓcould effectively remove microcystins from raw water containing a chl.a concentration of less than 1,000 $\mu\textrm{g}$/ℓ. The microcystin removal was more effective below pH 8.0, plus the optimum pH range was unrelated to the concentration of toxic algal material. Although chlorination is one of the most effective methods for reducing the toxin from blue-green algae, it causes cell lysis and toxin release. However, it was demonstrated that the released cell lysates and toxins could be effectively removed by a higher dose of the oxidant. The highest removal efficiency of dissolved microcystins(initial concentration: 280 $\mu\textrm{g}$ L$\^$-1/) was with a chlorine dose of 5.0 mg/ℓ.

• Toxicological Research
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• v.22 no.4
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• pp.375-380
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• 2006

Microcystin-LR (MC-LR) is a cyanobacterial hepatotoxin mainly produced by Microcystis aeruginosa. The current study examined the effects of a single intraperitoneal dose of MC-LR in rats. Female Sprague-Dawley rats were intraperitoneally injected with MC-LR ($100{\mu}g/kg$ body weight) and they were sacrificed at 0, 20, 40, 80, 160 min, or 12 h after injection. Clinically, animals showed lethargy and had ruffled hair beginning at 40 min post injection. In the gross findings, liver was enlarged and its color was changed into dark red beginning at 40 min post injection. Microscopically, dissociation of centrilobular hepatocytes and hemorrhage was observed in the hepatic central legions and such pathological changes were then extended to the portal regions of liver by time course manner. Interestingly at 80 min after MC-LR injection, the entrapped eosinophilic materials that may be necrotic fragments of dissociated hepatocytes were found in the capillaries of lung and renal glomerulus. Ultrastructurally, microvilli of the hepatocytes were disrupted or lost at all time points. Furthermore, the Disse space and gap junctions were widened beginning at 40 min post injection. These results suggest that liver is the major target organ of MC-LR and isolated hepatocytes by the effects of such hepatotoxin may secondarily reduce the physiological function of lung and kidney.

• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.843-850
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• 2012

Due to the fast response to algae bloom issue in drinking water treatment plant, very fast determination methodology for algal toxin is required. In this study, column switching technique based online preconcentration method was combined with high resolution full scan mass spectrometer to save sample preparation time and to obtain fast and accurate result. After parameter optimization of online preconcentration, 1mL filtered sample was directly injected to trap column with switching valve system. Next, target toxins are eluted by 98% acetonitrile and analysed with 150 - 1,100 amu scan range at 50,000 resolving power. Method detection limit (MDL) for microcystin-LR, the most toxic isomer, was 0.1 ng/mL and others such as microcystin-YR, microcystin-RR and nodularin were 0.08, 0.03 and 0.04 ng/mL, respectively. This is the best improved sensitivities with 1mL volume in the literature. Furthermore, due to the use of ultra pressure HPLC (UPLC), the whole method run was completed in 4 min. Real sample applications for 173 sample including 55 surface water and 118 treatment plant samples for raw and treated water could be done within 16 hours. In our calculation, this methodology is roughly 80% faster than the previous manual solid-phase extraction with LC-MS/MS method.

• Korean Journal of Ecology and Environment
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• v.43 no.3
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• pp.400-408
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• 2010

The growth and microcystins production characteristics of three species of Microcystis (M. aeruginosa, M. ichthyoblabe, M. viridis) isolated from Yeongchun dam and Ankei dam in Kyungpook Province, South Korea were investigated at temperatures of $15{\sim}35^{\circ}C$ and light intensities of $35{\sim}180\;{\mu}mol\;m^{-2}\;s^{-1}$. All of the three species exhibited the highest growth rates (${\mu}_{max}$) over the $30^{\circ}C$. The maximum growth rates of M. aeruginosa and M. ichthyoblabe was observed at $70\;{\mu}mol\;m^{-2}\;s^{-1}$, while M. viridis showed maximum growth rate at $35\;{\mu}mol\;m^{-2}\;s^{-1}$. The maximum production of total microcystins was observed at $20^{\circ}C$, and the production of microcystins decreased according as temperature increase. The highest microcystins production of M. aeruginosa, M. ichthyoblabe and M. viridis observed at light intensities of $120\;{\mu}mol\;m^{-2}\;s^{-1}$, $70\;{\mu}mol\;m^{-2}\;s^{-1}$ and $35\;{\mu}mol\;m^{-2}\;s^{-1}$, respectively. The concentration of microcyst in production and microcystin types of three species according to temperatures and light intensities showed clear difference between the species.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2001.12a
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• pp.132-132
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• 2001

• Journal of Microbiology and Biotechnology
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• v.10 no.3
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• pp.375-380
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• 2000

The preliminary screening of several cyanobacteria, using mice bioassay, reveale the production of a hepatotoxin by the cyanobacterium Scytonema sp. strain BT 23 isolated from soil. An intraperitoneal injection of the crude toxin (LD50 56 mg/kg body wt) from this strain caused the death of the mice within 40 min, and the anmals showed slinical signs of mice within 40 min, and the animals showed clinical signs of hepatotoxicity. The toxin was purified and partially characterized. The active fraction appears to be nonpolar in nature and shows absorption peaks at 240 and 285 nm. The purified toxin had an LD50 of TEX>$100<\mu\textrm{g}/kg$ body wt and the test mice died within 40 min of toxin administration. The toxin-treated mice showed a 1.65-fold increase in liver weight at 40 min and the liver color chnged to dark red due to intrahepatic hemorrhage and pooling of blood. Furthermore, the administration of the toxin to test mice induced a 2.58, 2.63, and 2.30-fold increse in the activity of the serum enzymes alanine aminotransferase, lactate dehydrogenase, and alkaline phosphatase, respectively. Further experiments with the 14C-labeled toxin revealed a maximum accumulation of the toxin in the liver. The clinical symptoms in the mice were similar to those produced by microcystin-L.R. These results suggest that hepatotoxins may also be produced in non bloom-forming planktonic cyanobacteria.

• Analytical Science and Technology
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• v.28 no.3
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• pp.168-174
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• 2015

Cyanobacterial toxins, such as microcystins, which exist in Korean lakes, are strongly toxic in fish, cattle, and humans. This study performs a quantitative analysis of cyanobacterial toxins in water by comparing the strip method and the HPLC method. Because the detection ranges of the strip method and the HPLC method are different, the water samples were diluted. The comparison of the strip method and the HPLC method was made using seven samples that contained different concentrations of microcystin. The quantitative results produced by the strip analysis were significantly aligned with the results of the HPLC analysis. The results of correlation analysis were r = 0.99998 and p = 0.00001.

• Journal of the Korean Chemical Society
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• v.46 no.6
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• pp.535-540
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• 2002

It is very difficult to analyze the microcystins, cyanobacterial toxins quantitatively since it exists in a trace level in lakes. In this paper, two different analytical methods were tried to analyze the microcystins, cyanobacterial toxins quantitatively in water samples collected in Soyang lake. The first method was solid phase extraction method fol-lowed by High Performance Liquid Chromatography(HPLC), and the second method was Enzyme-Linked Immu-nosorbent Assay(ELISA) using the monoclonal antibody of microcystin.