• Title, Summary, Keyword: Cyanobacteria

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Quantitative Risk Assessment of the Adverse Effects due to Exposure to Cyanobacteria Toxin (Microcystin-LR) through Drinking Water in the Nakdong River Watershed (수돗물을 통해 노출되는 녹조독소의 인체위해성 평가)

  • Lee, Jae-Hyun;Shin, Gwy-Am
    • Journal of Environmental Science International
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    • v.26 no.3
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    • pp.345-362
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    • 2017
  • The primary purpose of this study was to determine the risk of various disease outcomes due to exposure to cyanobacteria toxin (microcystin-LR) through drinking water in a Korean watershed. In order to determine the risk in a more quantitative way, the risk assessment framework developed by the National Research Council (NRC) of the United States (US) - hazard identification, dose-response relationship, exposure assessment, and risk characterization - was used in this study. For dose-response relationships, a computer software (BenchMark Dose Software (BMDS)) developed by the US Environmental Protection Agency (EPA) was used to fit the data from previous studies showing the relationship between the concentration of microcystin-LR and various disease outcomes into various dose-response models. For exposure assessment, the concentrations of microcystin-LR in the source water and finished water in a Korean watershed obtained from a recent study conducted by the Ministry of Environment of Korea were used. Finally, the risk of various disease outcomes due to exposure to cyanobacteria toxin (microcystin-LR) through drinking water was characterized by Monte-Carlo simulation using Crystall Ball program (Oracle Inc.) for adults and children. The results of this study suggest that the risk of disease due to microcystin-LR toxin through drinking water is very low and it appears that current water treatment practice should be able to protect the public from the harmful effects of cyanobacteria toxin (microcystin-LR) through drinking water.

Molecular Divergences of 16S rRNA and rpoB Gene in Marine Isolates of the Order Oscillatoriales (Cyanobacteria) (남조세균 흔들말목(Cyanobacteria, Oscillatoriales) 해양 균주의 16S rRNA와 rpoB 유전자 변이)

  • Cheon, Ju-Yong;Lee, Min-Ah;Ki, Jang-Seu
    • Korean Journal of Microbiology
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    • v.48 no.4
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    • pp.319-324
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    • 2012
  • In this study, we investigated molecular divergences and phylogenetic characteristics of the 16S ribosomal RNA (rRNA) and RNA polymerase beta subunit (rpoB) gene sequences from the order Oscillatoriales (Cyanobacteria). The rpoB of Oscillatoriales showed higher genetic divergence when compared with those of 16S rRNA (p-distance: rpoB=0.270, 16S=0.109), and these differences were statistically significant (Student t-test, p<0.001). Phylogenetic trees of 16S rRNA and rpoB were generally compatible; however, rpoB tree clearly separated the compared Oscillatoriales taxa, with higher phylogenetic resolution. In addition, parsimony analyses showed that rpoB gene evolved 2.40-fold faster than 16S rRNA. These results suggest that the rpoB is a useful gene for the molecular phylogenetics and species discrimination in the order Oscillatoriales.

Identification and toxigenic potential of a Nostoc sp.

  • Nowruzi, Bahareh;Khavari-Nejad, Ramezan-Ali;Sivonen, Karina;Kazemi, Bahram;Najafi, Farzaneh;Nejadsattari, Taher
    • 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.

Annual Fluctuation (2000 ${\sim}$ 2003) of Water Quality and Cyanobacterial Abundance in the Lower Part of Han-River (한강 하류의 남조류 및 환경요인의 연간 (2000 ${\sim}$ 2003) 변화에 대하여)

  • Suh, Mi-Yeon;Kim, Baik-Ho;Bae, Kyung-Seok;Han, Myung-Soo
    • Korean Journal of Ecology and Environment
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    • v.38 no.2
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    • pp.181-187
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    • 2005
  • For 4 years (2000 ${\sim}$ 2003), annual fluctuations of standing crops of cyanobacteria and physicochemical factors were examined at five sites from Bridge of Seungsoo to Bridge of Seungsan in the lower part of Han River. The cyanobacterial abundance (ND to 4,167 cells $mL^{-1}$) was strongly decreased during the heavy rains in every year. During the similar periods in 2003, cyanobacteria hardly observed, and comprised below of 10 percentage of total phytoplankton. In the period of little cyanobacteria, some green algae and diatom dominated the phytoplankton community, while the concentration of chlorophyll a has not largely change. These results indicate that heavy frequent precipitation strongly limited the growth of cyanobacteria, and lead an algal succession by the appearance of new algal groups.

A Study on Comparison of Phycocyanin Extraction Methods for Hyperspectral Remote Sensing of Cyanobacteria in Turbid Inland Waters (국내 담수역 남조류 원격탐사를 위한 피코시아닌 추출법 비교 연구)

  • Ha, Rim;Shin, Hyunjoo;Nam, Gibeom;Park, Sanghyun;Kang, Taegu;Song, Hyunoh;Lee, Hyuk
    • Journal of Korean Society on Water Environment
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    • v.32 no.6
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    • pp.520-527
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    • 2016
  • Phycocyanin (PC) is one of the water-soluble accessory pigments of cyanobacteria species, and its concentration is used to estimate the presence and relative abundance of cyanobacteria. In laboratory experiments, PC content of field data were determined using Sarada's freeze-thaw method in algal bloom season. The effectiveness of three selected extraction methods (repeated freeze-thaw method, homogenization, power control) for PC were determined. The extraction efficiency of phycocyanin was the highest (of the methods compared) when a single freezing-thawing cycle was followed by pre-sonication. Applying this optimized method to surface water of Korean inland waters, the average concentration distribution was estimated at $2.9{\sim}51.9mg/m^3$. It has been shown that the optimized pre-sonication method is suitable to measure cyanobacteria PC content for the characterization of inland waters. The approach and results of this study indicates the potential of effective methods for remote monitoring and management of water quality in turbid inland waters using hyperspectral remote sensing.

A study of newly recorded genus and species for aerial cyanobacteria Wilmottia murrayi(Oscillatoriales, Cyanobacteria) in Korea (기중성 남세균, Wilmottia murrayi (Oscillatoriales, Cyanobacteria)의 국내 미기록속 및 미기록종에 대한 연구)

  • Lee, Nam-Ju;Seo, Yoseph;Ki, Jang-Seu;Lee, Ok-Min
    • Korean Journal of Environmental Biology
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    • v.37 no.3
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    • pp.260-267
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    • 2019
  • Two aerophytic cyanobacteria from the rockwall of Haje port located in Geum river, Korea, were isolated in unialgal cultures and submitted to polyphasic evaluation. The filaments of the populations presented solitary or several to many parallel arranged. The straight trichomes were not attenuated with rounded apical cell. Phylogenetic analyses based on 16S rDNA sequences indicated that these populations formed the same clade with Wilmottia murrayi and had 99% or greater DNA similarity. Through the ultrastructure of the TEM, these populations showed parietal thylakoid arrangement, which coincides with family Coleofasciculaceae. From the above results, we reported the newly recorded genus Wilmottia, and species W. murrayi in Korea.

Synthesis of (R,R)-2,3-butanediol from starch in a hybrid cell-free reaction system

  • Yi, Tong;Lim, Hye Jin;Lee, So Jeong;Lee, Kyung-Ho;Kim, Dong-Myung
    • Journal of Industrial and Engineering Chemistry
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    • v.67
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    • pp.231-235
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    • 2018
  • In this study, we demonstrate the conversion of starch to (R,R)-2,3-butanediol (2,3-BD) in a hybrid cell-free synthesis system containing a mixture of lysates derived from Escherichia coli (E. coli) and cyanobacteria. A sufficient pool of pyruvate required for the synthesis of 2,3-BD was generated by combining metabolic pathways of cyanobacteria and E. coli. Successful synthesis of 2,3-BD was achieved by additional modifications of the hybrid cell-free system with the enzymes required to convert pyruvate to 2,3-BD. The results demonstrate a new approach to harness biological pathways to expand the scope of cell-free metabolic engineering by cross-species combinations of cell lysates.

A study on Asterocaelum sp., a grazer of filamentous cyanobacteria in the Lake Daecheong (대청호에서 사상 남조류 포식성 Asterocaelum sp.(Protozoan)의 발생에 관한 연구)

  • 천세억;박혜경;한홍의
    • Journal of environmental and Sanitary engineering
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    • v.15 no.1
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    • pp.1-6
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    • 2000
  • A milky gray scum was observed at some water area of the lake Daecheong in the summer of 1997 and 1998. To identify a causing organism of scum and affecting factors, we observed the scum material by a phase contrast microscope and surveyed the phsico-chemical water quality during the outbreak of scum. The scum was found out to be clogging cysts of amoeboid protozoan, Asterocaelum sp.(Protozoea Sarcodina Aconchulinida), grazer of filamentous cyanobacteria, Anabaena genus. The protozoan scum appeared during Anabaena bloom period, which continued for a while. This protozoan was presumed acting as a regulator of Anabaena bloom in the lake Daecheong during the summer season. Moreover this is the first report on Asterocaelum sp. a grazing filamentous cyanobacteria occurred in Korean freshwater.

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Differential Responses of Two Freshwater Cyanobacteria, Anabaena variabillis and Nostoc commune, to Sulfonylurea Herbicide Bensulfuron-methyl

  • KIM JEONG-DONG;LEE CHOUL-GYUN
    • Journal of Microbiology and Biotechnology
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    • v.16 no.1
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    • pp.52-56
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    • 2006
  • The effect of bensulfuron-methyl on the nontargeted cyanobacteria was greater on A. variabillis than N. commune. Both A. variabillis and N. commune were initially able to utilize low concentrations of the herbicide, bensulfuron-methyl, whereas higher concentrations of bensulfuron-methyl or the hydrolyzed products of the herbicide were found to be toxic. Growth and photosynthesis inhibitions of over $50\%$ were observed, when 8 to 10 ppm of the herbicide was applied. Nitrogenase activities of the cyanobacteria were decreased by $94-98\%$ in A. variabillis and by $85-86\%$ in N. commune after 24 h of incubation with 10 ppm and 20 ppm of bensulfuron-methyl. Nitrogenase activities were also inhibited by the addition of ammonium salts as low as 0.05 mM. Furthermore, the toxic effect of the herbicide was the highest at pH 4-6, showing approximately $42-60\%$ toxicity, whereas much lower toxicity $(9-28\%)$ was observed at higher pH of 7-10, due to base-catalyzed hydrolysis of bensulfuron-methyl.

Optimal condition for efficient DNA transfer in filamentous cyanobacteria by electroporation

  • Poo, Ha-Ryoung
    • Journal of Microbiology
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    • v.35 no.3
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    • pp.181-187
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    • 1997
  • Filamentous cyanobacteria are an ecologically important group of bacteria because they are able to provide both organic carbon fixed nitrogen that can support the nutritional requirements for other microorganisms. Because of their prokaryotic nature, they can also be used as potentially powerful model systems for the analysis of oxygenic photosynthesis and nitrogen fixation. Gene transfer is an indispensable procedure for genetic analysis of filamentous cyanobacteria. Electroporation was used to introduce foreign DNA into cyanobacterial cells. In experiments designed to optimize the electroporation technique, the effects of the field strength (amplitude of pulse) and time constant (duration of pulse), DNA concentration and host restriction/modification of DNA on the efficiency of electro-transformation were investigated. The results of this research revelaed that a high voltage pulse of short duration was effective for the electro-transformation of Anabaene sp. M131. The maximal number of transformants was obtained at 6 kV/cm with a pulse duration of 5 msec. The efficiency of electro-transformation was also sensitive to concenetration of DNA; even small amounts of DNA (0.01 .mu.g/ml) were able to gie a large number of transformants (1.0 * 10$\^$3/ cfu/ml).

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