• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.149-154
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• 2007

In the present study, we performed the PCR assay using TOX2P/TOX2M primer targeting a specific region within mcyB gene to identify potential microcystin-producing cyanobacteria. TOX2P/TOX2M primer set was effective in amplifying mcy gene in the field samples containing Microcystis spp. of 1,000 cells per mL. Moreover, the results from the PCR assay agreed with those of the ELISA analysis. Consequently, this study demonstrated that TOX2P/TOX2M primer set can be used as a genetic probe for the early detection of cyanobacterial toxigenicity in Korean water bodies.

• Analytical Science and Technology
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• v.25 no.6
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• pp.388-394
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• 2012

Cyanobacterial toxins, microcystins which exist in Korean lakes show strong toxicity to fish, cattles and human. In this study, we tried to analyze cyanobacterial toxin, microcystin in the Microcystis cultivation solution using test strip, although the most common analytical methods for the detection of microcystin are HPLC and ELISA. This new anlytical method used the advantages of high specifisity and rapidness of test strip, high sensitivity of fluorescence reader. Therefore, we could analyze the trace amount of microcystin existed in various water samples without using the microcystin standards.

• Proceedings of the Microbiological Society of Korea Conference
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• 2001.11a
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• pp.113-120
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• 2001

The production of microcystins from Microcystis aeruginosa was investigated in a P-limited continuous culture and a batch culture. The microcystin content of M aeruginosa was higher at a lower $\mu$, whereas the microcystin (MC)-producing rate was linearly proportional to $\mu$. The ratios of the MC-producing rate to the C-fixation rate were higher at a lower $\mu$. Consequently, increases in the microcystin content per dry weight along with the production of the more toxic form, MC-LR, were both observed under more P-limited conditions. The microcystin content of M. aeruginosa exhibited a high correlation with the total N content regardless of N-fixed or P-fixed culture. The microcystin concentration was investigated from spring to autumn in 1999 in the Daechung Reservoir, Korea. The dominant species in the algal blooming season was Microcystis. When the microcystin concentration exceeded about 100 ng $1^{-1}$ the ratio of particulate to dissolved total nitrogen (TN) or total phosphorus (TP) interestingly converged at a value of 0.6. The microcystin concentration was lower than 50 ng $1^{-1}$ at a particulate N:P ratio below 8, whereas the microcystin concentration varied quite substantially from 50 ng $1^{-1}$ to 250 ng $1^{-1}$ at a particulate N:P ratio> 8.

• ALGAE
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• v.17 no.3
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• pp.171-185
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• 2002

The standing crop of genus Microcystis, microcystin concentrations and environmental factors were monitored at stations of the lower reaches of the Nakdong River in 1998 and 1999 during the periods of its occurrence. The Microcystis were observed from May to Octorber, and the cell density was highest at Station Seonam up to 250,000 cells${\cdot}ml^{-1}$ forming scum over the water surface. There were signigicant relationships between the standing crop of Microcystis and nitrate nitrogen, total phosphorus concentrations and Ph. Presumably these parameters were important in the succession to Microcystis dominated phytoplankton community in the summer period in the river. However, Ammonium nitrogen, phosphate phosphorus concentrations and N/P ratio were not critical factors. The Microcystis bloom was notable above $25^{\circ}C$ of surface water temperature. Microcystins were detected from May to November in the algal materials from the river. The 84.2% of algal materials with Microcystis exhibited the microcystin with the maximum of 1711.8 ${\mu}g{\cdot}g^{-1}$ dw. The microcystin concentrations in the algal materials were significantly related to the stading crop of Microcystis, which was the primary determinant factor in the toxin levle of algal materials. The concentrations were also significantly related to pH of the water column in the positive pattern.

• Journal of Environmental Impact Assessment
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• v.20 no.6
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• pp.915-925
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• 2011

Following the industrialization and urbanization in Korea, algal bloom causes aesthetic displeasure and many other problems such as taste and odor, coloration, scum, increase in pH, filter-bed blockage. There were some cases involving human death by microcystins during summertime in foreign countries. In Korea, Harmful cyanobacteria such as Microcystis and Anabaena develop in summer in the Daecheong reservoir, one of the main water resources, with the retention time of above 200 days. To better control algal bloom, the Ministry of Environment has been running algal bloom alert system from 1998 for the Daecheong reservoir, which needs to be improved to reflect the characteristics of river-type lakes. For this reason, we try to find new measures to improve an algal bloom alert system for each water zone considering the characteristics of harmful cyanobacteria in this study.

• ALGAE
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• v.27 no.4
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• pp.303-313
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• 2012

Cyanobacteria are well known for their production of a multitude of highly toxic and / or allelopathic compounds. Among the photosynthetic microorganisms, cyanobacteria, belonging to the genus Nostoc are regarded as good candidate for producing biologically active secondary metabolites which are highly toxic to humans and other animals. Since so many reports have been published on the poisoning of different animals from drinking water contaminated with cyanobacteria toxins, it might be assumed that bioactive compounds are found only in aquatic species causes toxicity. However, the discovery of several dead dogs, mice, ducks, and fish around paddy fields, prompted us to study the toxic compounds in a strain of Nostoc which is most abundant in the paddy fields of Iran, using polymerase chain reaction and liquid chromatography coupled with a diode array detector and mass spectrophotometer. Results of molecular analysis demonstrated that the ASN_M strain contains the nosF gene. Also, the result of ion chromatograms and $MS^2$ fragmentation patterns showed that while there were three different peptidic compound classes (anabaenopeptin, cryptophycin, and nostocyclopeptides), there were no signs of the presence of anatoxin-a, homoanatoxin-a, hassallidin or microcystins. Moreover, a remarkable antifungal activity was identified in the methanolic extracts. Based on the results, this study suggests that three diverse groups of potentially bioactive compounds might account for the death of these animals. This case is the first documented incident of toxicity from aquatic cyanobacteria related intoxication in dogs, mice, and aquatic organisms in Iran.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.705-711
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• 2007

Green quantum-dot nanocrystal (QD525) with anti-microcystin monoclonal antibody was applied for detection of microcystin, a monocyclic peptide hepatotoxin, extracted from the culture of Microcystis aeruginosa. The presence of microcystin in the cell lysate was verified by HPLC analysis with UV absorbance at 238 nm. Microcystis cell extract exhibited fluorescence emission spectra, which peak was around 460 nm because of their complex organic substances. When a spherical QD525 antibody conjugates (10~20 nm in diameter) were bound to the microcystins in the Microcystis cell lysate, the fluorescence intensity of the primary peak at 525 nm diminished while the secondary emission peak at 460 nm slightly increased intensities. It is due to energy transfer from the primary (major) to the secondary (minor) peak, resulting from physical deformation of QD525 and different environmental factors. On the other hand, other cell extracts did not show any fluorescence emission change. This study is very available for detecting and monitoring the microcystin because it is one step assay without washing step and portable spectrophotometer makes on-site measurement possible. For health risk assessment of the microcystin, the reliable and rapid system to detect and quantify microcystin is seriously required.

• Journal of the Korean Chemical Society
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• v.48 no.5
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• pp.467-472
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• 2004

Cyanobacterial toxins, microcystins which exist in korean lakes show strong toxicity to fish, cattles and human. In this study, we tried to degrade microcystin LR using various chemical oxidants, Chlorine, Potassium permanganate and Hydrogen Peroxide. The detection method for the concentrations of microcystin LR in water samples was Enzyme-Linked Immunosorbent Assay (ELISA) method using the monoclonal antibody of microcystin. Chlorine degraded microcystin LR effectively at the concentration of 800 pg/mL microcystin LR and 12 ppm chlorine. The reaction took 40 minutes at pH 7. Potassium Permanganate also degraded microcystin LR successfully at the concentration of 2000 pg/mL microcystin LR and 1.2 ppm chlorine. The degradation reaction took 60 minutes at pH 7. In the case of hydrogen peroxide, the degradation rate of microcystin LR was very slow because of the slow reaction rate.

• 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.47 no.spc
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• pp.19-30
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• 2014

Microcystins (MCs) produced by cyanobacteria are severe hepatotoxins for mammalian and protein phosphatase inhibitors. Irrigation water for grain and vegetables is often contaminated with cyanobacteria and microcystin during warm seasons. We assessed the effects of various concentrations (0, 0.01 to $10{\mu}gmL^{-1}$) of microcystin-LR (MC-LR) and microcystin-RR (MC-RR) exposure on Oryza sativa (rice) and Brassica oleraces var. italica (broccoli). The $EC_{50}$ of leaves and roots of rice was 0.9 and $1.1{\mu}gMC-LRmL^{-1}$, respectively. The no observed effect level (NOEL) of rice was less than $0.1{\mu}gmL^{-1}$ ($100{\mu}gL^{-1}$). The $EC_{50}$ of the stems and roots of broccoli was 8.7 and $7.2{\mu}gMC-RRmL^{-1}$, respectively. There was no difference in the germination rate of broccoli among microcystin-RR concentrations. After exposure to 0, 0.01 to $10{\mu}gmL^{-1}$ MC-RR for seven days, 14, 89 and 154 ng mg-1 (dry weight) MC-RR accumulated in B. oleracea. These $EC_{50}$ values showed that microcystin-LR and -RR affected the growth of rice and broccoli. These findings suggest that MC is carried into terrestrial ecosystems via irrigation, and that the biota of higher ecological niches can be influenced by MC through bioaccumulation. Therefore, a guideline for MC concentrations in irrigation water should be set using the NOEL.