• Title/Summary/Keyword: Microcystin

Search Result 106, Processing Time 0.025 seconds

Establishment of an Axenic Culture of Microcystin-Producing Microcystis aeruginosa Isolated from a Korean Reservoir

  • Han, Ah-Won;Oh, Kyoung-Hee;Jheong, Weon-Hwa;Cho, Young-Cheol
    • Journal of Microbiology and Biotechnology
    • /
    • v.20 no.7
    • /
    • pp.1152-1155
    • /
    • 2010
  • In order to establish an axenic (bacteria-free) culture of Microcystis aeruginosa NIER 10039 isolated from a Korean reservoir, the culture was subjected to sequential treatment, including ultrasonication, washing, and addition of antibiotics. Three broad-spectrum antibiotics, namely, kanamycin, ampicillin, and imipenem, were applied separately in that order. Axenicity of the culture was confirmed by cultivation on bacterial media and observation under epifluorescence and scanning electron microscopes. We are the first to establish an axenic culture of a Microcystis strain isolated from Korean reservoirs and can be used in physiological and molecular studies to control toxic Microcystis blooms.

Degradation of Microcystin-LR, Taste and Odor, and Natural Organic Matter by UV-LED Based Advanced Oxidation Processes in Synthetic and Natural Water Source (UV-LED기반 고도산화공정을 이용한 수중 마이크로시스틴-LR, 이취미 물질, 자연유기물 분해)

  • Yang, Boram;Park, Jeong-Ann;Nam, Hye-Lim;Jung, Sung-Mok;Choi, Jae-Woo;Park, Hee-Deung;Lee, Sang-Hyup
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.39 no.5
    • /
    • pp.246-254
    • /
    • 2017
  • Microcystin-LR (MC-LR) is one of most abundant microcystins, and is derived from blue-green algae bloom. Advanced oxidation processes (AOPs) are effective process when high concentrations of MC-LR are released into a drinking water treatment system from surface water. In particular, UV-based AOPs such as UV, $UV/H_2O_2$, $UV/O_3$ and $UV/TiO_2$ have been studied for the removal of MC-LR. In this study, UV-LED was applied for the degradation of MC-LR because UV lamps have demonstrated some weaknesses, such as frequent replacements; that generate mercury waste and high heat loss. Degradation efficiencies of the MC-LR (initial conc. = $100{\mu}g/L$) were 30% and 95.9% using LED-L (280 nm, $0.024mW/cm^2$) and LED-H (280 nm, $2.18mW/cm^2$), respectively. Aromatic compounds of natural organic matter changed to aliphatic compounds under the LED-H irradiation by LC-OCD analysis. For application to raw water, the Nak-dong River was sampled during summer when blue-green algae were heavy bloom in 2016. The concentration of extracellular and total MC-LR, geosmin and 2-MIB slightly decreased by increasing the LED-L irradiation; however, the removal of MC-LR by UV-LED (${\lambda}=280nm$) was insufficient. Thus, advanced UV-LED technology or the addition of oxidants with UV-LED is required to obtain better degradation efficiency of MC-LR.

Growth inhibition of hydrotrope-combined copper against Microcystis aeruginosa and evaluation of its toxicity (Microcystis aeruginosa에 대한 hydrotrope-combined copper의 생장억제 및 독성 평가)

  • Park, Se-Keun;Ji, Jun-Gu;Jang, Hee Jung;Kim, Yeong-Kwan;Oh, Young-Sook;Choi, Sung-Chan
    • Korean Journal of Microbiology
    • /
    • v.51 no.1
    • /
    • pp.7-13
    • /
    • 2015
  • Hydrotrope-combined copper (HCC) is a copper ($Cu^{2+}$)-based algicide, which is combined with a hydrotrope that keeps copper ion in solution to improve performance. This study assessed the growth inhibition effect of HCC against Microcystis aeruginosa which is one of the most common toxic cyanobacterium in eutrophic freshwater environment. Various HCC doses, ranging from 5.5 to $550{\mu}g/L$ as $Cu^{2+}$, were applied to either BG-11 or 1/4 diluted medium with low- or high-inoculum density of M. aeruginosa. Growth inhibition was monitored based on a decrease in chlorophyll-a content in culture medium during the incubation. Results showed that HCC significantly inhibited the growth of M. aeruginosa in a dose-dependent manner. In case of 1/4 diluted BG-11 medium, HCC dose as low as $5.5{\mu}g$ $Cu^{2+}/L$ completely inhibited the production of chlorophyll-a by M. aeruginosa. It was found that HCC did not induce any significant release of microcystin-LR from M. aeruginosa. Acute toxicity of HCC was tested using Daphnia magna, and the 24-h $EC_{50}$ value was 0.30 mg/L as $Cu^{2+}$ which was much higher than the actual inhibition dose. Ames test was performed using Salmonella enterica serovar Typhimurium TA100, and HCC showed no increase in the number of revertant colonies. The result suggested that HCC does not have any mutagenic potential in the aquatic environment. In addition, no genotoxic effect of HCC was also confirmed based on the SOS ChromoTest using Escherichia coli PQ37. Therefore, HCC could be used as a relatively safe and effective pre- and post-treatment agent to control hazardous algal blooming in aquatic environments.

Development of mcyB-specific Ultra-Rapid Real-time PCR for Quantitative Detection of Microcystis aeruginosa (Microcystis aeruginosa의 정량을 위한 mcyB 특이 초고속 실시간 유전자 증폭법의 개발)

  • Jung, Hyunchul;Yim, Byoungcheol;Lim, Sujin;Kim, Byounghee;Yoon, Byoungsu;Lee, Okmin
    • Journal of Korean Society on Water Environment
    • /
    • v.34 no.1
    • /
    • pp.46-56
    • /
    • 2018
  • A mcyB-specific Ultra-Rapid quantitative PCR was developed for the quantitative detection of Microcystis aeruginosa, which is often a dominant species in green tide. McyB-specific UR-qPCR was optimized under extremely short times of each step in thermal cycles, based on the specific primers deduced from the mcyB in microcystin synthetase of M. aeruginosa. The M. aeruginosa strain KG07 was used as a standard for quantification, after the microscopic counting and calculation by mcyB-specific UR-qPCR. The water samples from the river water with the Microcystis outbreak were also measured by using both methods. The $1.0{\times}10^8$ molecules of mcyB-specific DNA was recognized inner 4 minutes after beginning of UR-qPCR, while $1.0{\times}10^4$ molecules of mcyB-specific templates was detected inner 7 minutes with quantitative manner. From the range of $1.0{\times}10^2$ to $1.0{\times}10^8$ initial molecules, quantification was well established based on $C_T$ using mcyB-specific UR-qPCR (Regression coefficiency, $R^2=0.9977$). Between the numbers of M. aeruginosa cell counting under microscope and calculated numbers using mcyB-specific UR-qPCR, some differences were often found. The reasons for these differences were discussed; therefore, easy compensation method was proposed that was dependent on the numbers of the cell counting. Additionally, to easily extract the genomic DNA (gDNA) from the samples, a freeze-fracturing of water-sample using liquid nitrogen was tested, by excluding the conventional gDNA extraction method. It was also verified that there were no significant differences using the UR-qPCR with both gDNAs. In conclusion, the mcyB-specific UR-qPCR that we proposed would be expected to be a useful tool for rapid quantification and easy monitoring of M. aeruginosa in environmental water.

Accumulation of Microcystins in Fish and Evaluation of Potential Human Health Risks: A Case Study on a Eutrophic Reservoir in Korea (마이크로시스틴의 어류내 축적성 및 인체 위해성 평가: 국내 저수지 사례연구)

  • Yoon, Hyojung;Seo, Jungkwan;Kim, Taksoo;Jo, Areum;Kim, Jungkon;Lee, Doohee;Kim, Pilje;Choi, Kyunghee
    • Journal of Environmental Health Sciences
    • /
    • v.42 no.1
    • /
    • pp.10-18
    • /
    • 2016
  • Objectives: Microcystin (MC) produced during cyanobacterial blooms is a worldwide problem presenting a serious health threats to humans and ecosystems. During July through October of 2013, the Ilwol Reservoir experienced a high biomass of phytoplankton (maximum $211.7mg/m^3$ of Chlorophyll-a) containing the toxigenic cyanobacterium Oscillatoria sp. The aim of this study is to analyze MC concentration in the reservoir water, as well as in representative fish species (Carassius cuvieri, Carassius auratus, Channa argus). We also evaluated the human health risk of exposure to MCs accumulated in the fish. Methods: Concentrations of MCs in the water and fish samples were analyzed by liquid chromatography with a triple quadrupole tandem mass spectrometer (LC/MS/MS) and enzyme-linked immunosorbent assay (ELISA). Results: The total levels of four MC variants, including MC-LR, MC-RR, MC-YR and MC-LA were below the WHO drinking water guideline limit (1 ug MC-LR per liter) both for the dissolved and particulate fraction present in the water samples. The mean MC concentrations in the livers of all species were significantly higher than in the gills (p < 0.01) and muscles (p < 0.05). The values of estimated daily intake of MCs in muscles, the edible part of the fish, would be only $0.005-0.015{\mu}g/kg{\cdot}day$, much lower than WHO's provisional tolerable daily intake of $0.04{\mu}g/kg{\cdot}day$. Conclusion: This study suggests that, owing to the spatial distribution or temporal variation of MC, there is a need for careful monitoring of cyanotoxin in reservoir water and aquatic animals to protect public health.

Reproduction of Water Flea by the Culture Conditions (배양조건에 따른 물벼룩의 개체생산 특성)

  • Choe, Sung-Hun;Lim, Byung-Jin
    • Korean Journal of Ecology and Environment
    • /
    • v.36 no.2 s.103
    • /
    • pp.208-214
    • /
    • 2003
  • Four species of water fleas (Daphnia magna, Daphnia pulex, Daphnia galeata, and Moina macrocopa) were examined for the clarification of their reproduction with culture conditions. The reproduction tests of water flea by the culture conditions were carried out. For the comparison of the reproduction rate, five media (manure-soil medium, DIN medium, M4 medium, EPA medium, fertilizer medium) were applied to determine the best medium. Daphnia magna, Daphnia pulex, and Moina macrocopa were appeared the best reproduction in the manure-soil medium at $20^{\circ}C.$ The lifespan and young reproduction were better in manure-soil medium than the others. But Daphnia galeata was lived for 34 days in the fertilizer medium at $20^{\circ}C.$ The culture of Daphnia galeata was difficult to rear than the other species. In the current study, the microcystin of Microcystis sp. did not particularly affect on the survival of water fleas. But the lifespan was short and the reproduction rate was low. Therefore water flea have a preference for Scenedesmus sp. than Microcystis sp. On the condition of the feeding Scenedesmus sp., all examined water fleas appeared to have the longest lifespan and the most young water fleas produced at any medium and temperature as compared with the feeding the Microcystis sp. For the culture temperature, the lifespan was longer on $20^{\circ}C$ than $15^{\circ}C$.

Evaluation of Growth Inhibition for Microcystis aeruginosa with Different Frequency of Ultrasonic Devices (초음파 장치의 주파수 변화에 따른 Microcystis aeruginosa의 성장억제 평가)

  • Jang, So Ye;Joo, Jin Chul;Kang, Eun Byeol;Ahn, Chae Min;Park, Jeongsu;Jeong, Moo Il;Lee, Dong Ho
    • Ecology and Resilient Infrastructure
    • /
    • v.8 no.3
    • /
    • pp.143-153
    • /
    • 2021
  • The growth inhibition effects of M. aeruginosa were verified using large volume (7.2 L) of algae samples and ultrasonication (high frequency of 1.6 MHz vs. low frequency of 23 kHz) in lab-scale experiment. The chlorophyll-a (chl-a) and cell number decreased gradually after 6 hr sonication with high frequency of 1.6 MHz whereas both decreased sharply after 6 hr sonication with low frequency of 23 kHz. Additionally, the first order degradation coefficient (k) values after sonication were greater than those during sonication. These results indicate that relatively low sonication energy per volume may affect the cell membrane and internal organs of M. aeruginosa in a slow and retarded manner and resulted in gradual decrease of cell numbers of M. aeruginosa. Based on the comparison of chl-a and cell number of M. aeruginosa after sonication, low frequency of 23 kHz is superior for growth inhibition of M. aeruginosa, since low frequency of 23 kHz easily penetrates the cell membrane and ruptures the internal organs including gas vesicles. As is evident in SEM and TEM images, ruptured cell membranes were clearly observed for low frequency of 23 kHz. Finally, the microcystin-LR in water is not detected and considered to be harmless in aquaculture systems.

Detection and Quantification of Toxin-Producing Microcystis aeruginosa Strain in Water by NanoGene Assay

  • Lee, Eun-Hee;Cho, Kyung-Suk;Son, Ahjeong
    • Journal of Microbiology and Biotechnology
    • /
    • v.27 no.4
    • /
    • pp.808-815
    • /
    • 2017
  • We demonstrated the quantitative detection of a toxin-producing Microcystis aeruginosa (M. aeruginosa) strain with the laboratory protocol of the NanoGene assay. The NanoGene assay was selected because its laboratory protocol is in the process of being transplanted into a portable system. The mcyD gene of M. aeruginosa was targeted and, as expected, its corresponding fluorescence signal was linearly proportional to the mcyD gene copy number. The sensitivity of the NanoGene assay for this purpose was validated using both dsDNA mcyD gene amplicons and genomic DNAs (gDNA). The limit of detection was determined to be 38 mcyD gene copies per reaction and 9 algal cells/ml water. The specificity of the assay was also demonstrated by the addition of gDNA extracted from environmental algae into the hybridization reaction. Detection of M. aeruginosa was performed in the environmental samples with environmentally relevant sensitivity (${\sim}10^5$ algal cells/ml) and specificity. As expected, M. aeruginosa were not detected in nonspecific environmental algal gDNA over the range of $2{\times}10^0$ to $2{\times}10^7$ algal cells/ml.

Molecular characterization of glutathione peroxidase gene from the liver of silver carp, bighead carp and grass carp

  • Li, Guang-Zhao;Liang, Xu-Fang;Yao, Wei;Liao, Wan-Qin;Zhu, Wei-Feng
    • BMB Reports
    • /
    • v.41 no.3
    • /
    • pp.204-209
    • /
    • 2008
  • The cDNAs encoding glutathione peroxidase (GPx) were cloned and sequenced from the liver of three Chinese carps with different tolerance to hepatotoxic microcystins, phyto-planktivorous silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis), and herbivorous grass carp (Ctenopharyngodon idellus). Using genome walker method, a 750 bp 5'-flanking region of the silver carp GPx gene was obtained, and several potential regulatory elements were identified in the promoter region of the GPx gene. The silver carp GPx gene was widely expressed in all tissues examined. Despite phylogenetic analysis, assigning this newly described carp GPx to the group of mammalian GPx2, the carp GPx seems more similar to GPx1 from a physiological point of view. The constitutive expression pattern of the three carp liver GPx gene, shows a positive relationship with their tolerance to microcystins.

Reduction of Blue-green Algae and Its By-products using Intake of Deep Water in Summer (하절기 심층취수를 이용한 남조류 및 남조류 부산물질의 유입 저감)

  • Park, Hong-Ki;Jung, Eun-Young;Son, Hee-Jong;Choi, Jin-Taek
    • Journal of Environmental Science International
    • /
    • v.26 no.3
    • /
    • pp.393-399
    • /
    • 2017
  • In order to determine the optimal water intake point, the distribution of blue-Green algae and water quality factors in relation to the depth of the Mulgum and Maeri stations located downstream of the Nakdong River were investigated from Jun. 2015 to Sep. 2016. When the current surface water intake system was converted to the deep water intake system, Chl-a concentration and blue-Green algae were reduced by 64.1% and 80.5%, respectively. Microcystin-LR was reduced by 50% to 100%, while geosmin and 2-MIB of the odorant substances were reduced by 42.9% and 11.8%, respectively. The water quality factors such as pH, water temperature, TOC and COD were gradually decreased by 30% in deep water. Therefore, if we used the deep water intake system selectively in the summer season when blue-Green algae masses occur, the concentration of the influx of blue-green algae and its by-products can be expected to decrease, leading to reduced operation costs in tap water production and improved of raw water quality.