• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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• pp.11-44
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• 2005

The occurrence of toxic cyanobacterial blooms has been reported worldwide and pose a threat to human health through drinking water exposure. The toxins they produced are highly water soluble and can leach into the water body. To eliminate any risk of drinking water exposure, removal of these toxins is essential before the water is consumed. Conventional water treatment techniques such as chlorination, if managed well, can be effectively used to remove some of these toxins, however, saxitoxin and derivatives pose a problem. Little toxicological data are available to evaluate the real threat of these toxins.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.1
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• pp.93-101
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• 2017

In this study, we investigated the correlation between the number of cyanobacterial species and the water quality factors after installation of Nakdong river weirs. Factor analyses of water quality factors were also performed. The results of correlations showed that there was no significant water quality with the cyanobacterial concentration but the correlation coefficient of nutrients increased from the upstream to the downstream. There was a significant correlation between W T and pH as important water quality factors for the growth of cyanobacteria. In the downstream region of Nakdong river, algae were more frequently detected than in the upstream region, and the blooms of algae species seem to be influenced by the higher pH and the influx of the phosphorus from the upstream tributaries. Nutrient concentration was higher in the downstream region than in the upstream region due to the effects of tributaries Geumho river and Nam river in Nakdong river. As a result of the factor analyses, nitrogen species were the principal factors in the upper region, and phorsphorus species were the principal factors in the downstream region.

• Korean Journal of Ecology and Environment
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• v.33 no.3 s.91
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• pp.206-212
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• 2000

Since some cyanobacterial isolates under selective culturing conditions are lacking of characteristic specialized cells or showing altered morphology, the morpho-taxonomic criteria are not accurate enough to discriminate between species. Instead of morphological parameters, a method based on the single or the combination of repetitive oligonucleotides in a single PCR, repetitive oligonucleotides-primed PCR (ROP-PCR), was applied to generate DNA profiles for members of the cyanobacterial genera Anabaena and Oscillatoria, both of which are responsible for causing poisonous blooms in various freshwater systems. ROP-PCR performed on 10 isolates of the cyanobacteria with ERIC and REP sequences from gram-negative bacteria, STRR1A and LTRR sequences derived from cyanobacterial genome, and eukaryotic repetitive sequences, led to the identification of distinct genotypes, and provided specific and repeatable DNA fingerprints for cyanobacterial isolates. Grouping analysis of cyanobacterial isolates showed a signifiant difference depending on the primer used in PCR.

• Ecology and Resilient Infrastructure
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• v.6 no.1
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• pp.77-77
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• 2019

• Journal of Korean Society on Water Environment
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• v.34 no.4
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• pp.375-381
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• 2018

The monitoring of phytoplankton biomass and community structure is essential as a first step to control the harmful cyanobacterial blooms in freshwater systems, such as seen in rivers and lakes, due to the process of eutrophication and climate change. In order to quantify the biomass of phytoplankton with a wide range in size and shape, the measurement of cell biovolume along with cell density is required for a comprehensive review on this issue. However, most routine monitoring programs preserve the gathered phytoplankton samples before analysis using chemical additives, because of the constraint of time and the number of samples. The purpose of this study was to investigate the cell biovolume change characteristics of six cyanobacterial species, which are common bloom-causing cyanobacteria in the Nakdong River, after the preservation with Lugol's iodine solution. All species showed a statistically significant difference after the addition of Lugol's iodine solution compared to the live cell biovolume, and the cell biovolume decreased to the level of 34.0 ~ 56.3 % at maximum in each species after the preservation. The nonlinear regression models for determining the shrinkage ratio by a preservation period were derived by using the cell biovolume measured until 180 days preservation of each target species, and the equation to convert the cell biovolume measured after preservation for a certain period to the cell biovolume of viable cell was derived using that formula. The conversion equation derived from this study can be used to estimate the actual cell biovolume in the natural environment at the time of sampling, by using the measured biovolume after the preservation in the phytoplankton monitoring. Moreover this is expected to contribute to the final interpretation of the water quality and aquatic ecosystem impacts due to the cyanobacterial blooms.

• Korean Journal of Ecology and Environment
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• v.44 no.1
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• pp.22-30
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• 2011

This study was purposed to develop an effective LC/MS/MS method for simultaneously determining five pre-treated cyanotoxins (anatoxin-a, microcystins-RR, -YR, -LR and -LA) of cyanobacteria blooms. Cyanobacterial bloom samples were collected from 11 major lakes and three downstream areas of river around Korea during 2005~2009. Cyanotoxins were identified in 38 samples from the lakes. The validity of the method was evaluated and the recovery rates were found ranging from 83~87%. The MDL turned out to be $0.046\;{\mu}g\;L^{-1}$ for anatoxin-a and $0.066\;{\mu}g\;L^{-1}$ for microcystins (RR, YR, LR and LA), which indicates that the method has high sensitivity and accuracy. The most dominant genus of the cyanobacterial blooms was Microcystis, which accounted for 71% of the analysed samples. Microcystis also contained the largest amount of microcystins ($398.5\;{\mu}g\;gDW^{-1}$) among the analyzed cyanobacteria. The analysis of the five cyanotoxins showed that anatoxin-a ranged between $0{\sim}41.833\;{\mu}g\;gDW^{-1}$ and microcystins ranged between $6.311{\sim}2,148.786\;{\mu}g\;gDW^{-1}$. Among the microcystins, micocystin-RR took up 58.3%, the largest portion. Anatoxin-a was found to account for 77.8% of the samples. This study has its significance in that it allowed the establishment of toxin criteria appropriate for the Korean water systems. Further studies may be necessary to conduct for improving water treatment methods.

• Korean Journal of Ecology and Environment
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• v.34 no.1 s.93
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• pp.45-53
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• 2001

Transport of cyanobacterial toxins (microcystin-LR, -RR, -YR) were assessed from a eutrophic lake, Lake Suwa, through the outflowing river, the Tenryu River, and its irrigation channel branch. Temporal variation of phytoplankton species composition in the river coincided with those of the lake; Microcystis ichthyoblabe dominated from June to July, and M. viridis dominated from August to September. When cyanobacterial bloom occurred, microcystins were continuously detected at the concentration of $0.3{\sim}3.2\;{\mu}g/l$ even at 32 km downstream. The change of the content of three microcystin variants were related both with the total cell density of Microcystis and with the change of Microcystis species composition. When Microcystis ichthyoblabe dominated during July, only microcystin-RR (MC-RR) and -LR (MC-LR) were detected, while when Microcystis viridis dominated between August and October, microcystin-RR,-YR (MC -YR) and -LR were detected. Along 29 km flowing distance (flow time 11 hours) between site 2 and site 5 in the Tenryu River, cyanobacterial density and microcystin concentration were reduced by 73% and 72%, respectively, which is mostly contributed by the dilution effect of tributary waters (61% and 57%, respectively) . In the artificial irrigation channel microcystins and cyanobacterial cells were decreased less than in the natural river. The results indicate that cyanobacterial toxins can be transported far downstream without much removal and give hazards to water usage in downstream of eutrophic lakes with cyanobacterial blooms.

• Journal of Microbiology
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• v.42 no.3
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• pp.181-187
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• 2004

Cyanobacteria are the dominant phototrophic bacteria in water environments. Here, the diversity of cyanobacteria in seven Korean reservoir waters where different levels of algal blooms were observed during the summer of 2002, was examined by T-RFLP analysis. The number of T-RF bands in the HaIII T-RFLP profiles analyzed from those water samples ranged from 20 to 44. Of these, cyanobacteria accounted for 6.1 to 27.2％ of the total bacteria. The water samples could be clustered into 2 groups according to the Dice coefficient of the T -RF profiles. The eutrophic Dunpo and oligotrophic Chungju reservoirs were selected, and several representative clones from both reservoir waters analyzed for the nucleotide sequences of their 16S rDNA. The major clones were found to belong to the Microcystis and Anabaena species in the waters from the Dunpo and Chungju reservoirs, respectively, which was in agreement with the T-RFLP result. That is, the Microcystis and Anabaena species were dominant in the eutrophic and polluted Dunpo and oligotrophic Chungju reservoir waters, respectively. These results indicated that there is a correlation between prevalence of cyanobacterial species and levels of pollution in reservoir waters.

• Journal of Microbiology
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• v.37 no.3
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• pp.159-167
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• 1999

The effects of bicarbonate concentration, atmospheric carbon dioxide level, and reduced atmospheric oxygen on biomass and geosmin production and geosmin/biomass (G/B) values for Streptomyces halstedii, a producer of the off-flavor compound geosmin, were determined. In addition, a study was performed to determined possible synergistic relationships between a cyanobacterium, Oscillatoria tenuis UTEX #1566, and S. halstedii in the enhancement of actinomycete growth and/or geosmin production. These studies took into consideration those conditions that can occur during cyanobacterial bloom die-offs. Increasing bicarbonate concentration caused slight decreases in geosmin production and G/B for S. halstedii. Increasing atmospheric oxygen promoted geosmin production and G/B while lower oxygen levels resulted in a decrease in geosmin production and G/B by S. halstedii. Biomass production by S. halstedii was adversely affected by reduced oxygen levels while changes in bicarbonate concentration and atmospheric carbon dioxdie levels had little effect on biomass production. Sonicated cells of O. tenuis UTEX #1566 promoted biomass production by S. halstedii, and O. tenuis culture (cells and extracellular metabolites) and culture supernatnat (extracellular metabolites) each promoted geosmin and G/B yields for S. halstedii. In certain aquatic systems, environmental conditions resulting from cyanobacterial blooms and subsequent bloom die-offs could favor actinomycete growth and off-flavor compound by certain actinomycetes.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.601-609
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• 2018

Microcystis aeruginosa, a freshwater cyanobacteria species known to be one of the most predominant species responsible for cyanobacterial harmful algal blooms (CyanoHABs). It has been frequently associated with the contamination of neurotoxins and peptide hepatotoxins, such as microcystin and lipopolysaccharides-LPSs. CyanoHABs control technologies so far put in place do not provide a fundamental solution and cause secondary pollution linked with the control measures. For this study, algicidal peptides, which have been reported to be non-toxic and to have antimicrobial properties, were employed for the development of novel eco-friendly control against CyanoHABs. The four peptides (CMA1, CMA2, HPA3P, and HPA3NT3) selected in this study showed significant algicidal effects against M. aeruginosa cells inducing cell aggregation and flotation. Moreover, the newly generated peptides (K160242-5) with certain modifications also displayed high algicidal activity. The algicidal activity of the peptides was found to depend on the concentrations and structures of each of amino acid. The results of this study suggested a novel possibility of CyanoHABs control using the non-toxic algicidal peptides.