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

• Korean Journal of Ecology and Environment
• /
• v.36 no.3 s.104
• /
• pp.269-276
• /
• 2003

The study was performed to understand the relationships of cyanobacterial bloom and environmental factors in Lake Daechung. The samples were collected weekly from June to October in 2001. The cyanobacterial bloom was divided into the three phases of the early phase, the middle phase and the late phase by phytoplankton standing crops. For the early phase, the correlation coefficients between chl- a and TP, and chl- a and $PO_4$-P were 0.986 and 0.894 respectively. Therefore, phosphorus was a main environmental factor in the development of cyanobacterial bloom. Zeu/Zm ratio and chl-a showed negative correlation of r = -0.995. At the late phase, $PO_4$-P showed the highest relationship (r = 0.958), and TP and temperature showed relatively high relationships (r = 0.857 and r = 0.813). At the late phase, $NH_3$-N showed highly positive relationship (r = 0.921). It was confirmed that $PO_4$-P was the most important contribution factor for the bloom through the regression analysis on the environmental factors. As the result, the decrease of Zeu/Zm ratio and the increase of P concentration influenced cyanobacterial bloom developed rapidly in the early phase. Also the cyanobacterial bloom was decreased in proportion to decreasing of $NH_3$-N concentration in the late phase. It was expected that observation of $NH_3$-N may be a very useful factor on monitoring of the decreasing situation of the bloom.

• Analytical Science and Technology
• /
• v.28 no.3
• /
• pp.168-174
• /
• 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
• /
• v.46 no.6
• /
• pp.535-540
• /
• 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.

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

• Journal of Korean Society on Water Environment
• /
• v.26 no.5
• /
• pp.834-840
• /
• 2010

To find out the toxin production characteristics of Korean harmful cyanobacteria, we isolated 14 cyanobacterial strains from Korean lakes and rivers and analyzed the kinds and cellular content of microcystins (MCYSTs) of cyanobacterial isolates using cultured biomass. And we measured the MCYSTs production by growth phase of two representative toxic strains, Microcystis aeruginosa (HG-015) and Anabaena planktonica (HG-012). Among seven cyanobacteral species, Microcystis wesenbergii showed the highest cellular MCYSTs content. MCYST-RR was the most dominant toxin reaching more than 85% of MCYSTs produced by isolated cyanbacterial strains. During the mass culture, Microcystis aeruginosa (HG-015) showed the highest yield and accumulation of MCYSTs in the exponential growth phase. However the cellular content of chlorophyll a and MCYSTs of Anabaena planktonica (HG-012) showed higher value in the stationary and early death phase than in the exponential growth phase. Our results suggest that control and removal of harmful cyanobacterial bloom before exponential growth phase may be effective to prevent health risk of cyanobacterial toxins in the drinking water sources.

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

• Journal of Environmental Health Sciences
• /
• v.31 no.3
• /
• pp.192-198
• /
• 2005

The occurrence of toxic cyanobacterial blooms has been reported worldwide and poses a threat to human health through drinking water exposure. The toxins they produce 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 its derivatives pose a problem. Little toxicological data are available to evaluate the real threat of these toxins.

• ALGAE
• /
• v.18 no.3
• /
• pp.233-238
• /
• 2003

Cyanobacteria were dominant from June to September in the Nakdong River and the Hoedong Reservoir. Microcystis aeruginosa was dominant from June to September; Anabaena flos-aquae from June to August and Aphanizomenon flos-aquae from July to August. Cyanobacterial neurotoxins, Anatoxin-a and saxitoxin were analyzed by electrospray ionization-mass spectrometry with strains of Aphanizomenon flos-aquae NIES-81 and Anabaena flosaquae NIER-10002. Anatoxin-a was not detected from the cultured Anabaena flos-aquae nor from the wild samples. Low levels of saxitoxin were detected in the cultured Aphanizomenon flos-aquae however, those of field samples were below the detection limit.

• Molecules and Cells
• /
• v.43 no.6
• /
• pp.509-516
• /
• 2020

To perceive fluctuations in light quality, quantity, and timing, higher plants have evolved diverse photoreceptors including UVR8 (a UV-B photoreceptor), cryptochromes, phototropins, and phytochromes (Phys). In contrast to plants, prokaryotic oxygen-evolving photosynthetic organisms, cyanobacteria, rely mostly on bilin-based photoreceptors, namely, cyanobacterial phytochromes (Cphs) and cyanobacteriochromes (CBCRs), which exhibit structural and functional differences compared with plant Phys. CBCRs comprise varying numbers of light sensing domains with diverse color-tuning mechanisms and signal transmission pathways, allowing cyanobacteria to respond to UV-A, visible, and far-red lights. Recent genomic surveys of filamentous cyanobacteria revealed novel CBCRs with broader chromophore-binding specificity and photocycle protochromicity. Furthermore, a novel Cph lineage has been identified that absorbs blue-violet/yellow-orange light. In this minireview, we briefly discuss the diversity in color sensing and signal transmission mechanisms of Cphs and CBCRs, along with their potential utility in the field of optogenetics.