WorldWideScience

Sample records for lemna gibba microcystin

  1. Bio-accumulation and toxicity of lead (Pb) in Lemna gibba L (duckweed).

    Science.gov (United States)

    Sobrino, Alma S; Miranda, Maria G; Alvarez, Carlos; Quiroz, Agustin

    2010-01-01

    The vascular aquatic plant Lemna gibba (duckweed) was exposed during seven days to lead (Pb) at concentrations ranging from 50 to 300 mg/L in a greenhouse with controlled photoperiod and temperature. The effects of Pb on growth of Lemna gibba were examined during 13 days in the same experimental design. The maximum accumulation of lead by Lemna gibba occurs during the third day in the 50 mg/L test, and at the sixth day, lead in all test concentrations produces approximately a 100% inhibitory effect on duckweed growth. In all tests, the maximum relative growth rates were achieved on the third day and then, the toxicity effects were: 59.3% total soluble starch reduction; 94.7% total soluble proteins reduction; 246% increase in total soluble amino acids; 50% increase in total soluble sugars and an 18.2% increase in total phenols. This experiment showed that the transfers of Pb from nutritive solution to plants were fast. Nevertheless, Pb produced toxic effects on Lemna gibba; however duckweed was able to remove Pb at the experimental concentrations used.

  2. Functional analysis of a Lemna gibba rbcS promoter regulated by ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 92; Issue 1. Functional analysis of a Lemna gibba rbcS ... Photosynthesis-associated nuclear genes (PhANGs) are able to respond to multiple environmental and developmental signals, including light, sugar and abscisic acid (ABA). PhANGs have been extensively studied at the ...

  3. Growth Recovery of Lemna gibba and Lemna minor Following a 7-Day Exposure to the Herbicide Diuron.

    Science.gov (United States)

    Burns, Mitchell; Hanson, Mark L; Prosser, Ryan S; Crossan, Angus N; Kennedy, Ivan R

    2015-08-01

    In agricultural catchments, aquatic ecosystems can experience a pulse exposure to pesticides. Following such exposure, non-target organisms that are not extirpated may recover. This paper investigates the potential of two duckweed species (Lemna minor and Lemna gibba) to recover from a 7-day exposure to different concentrations (0.4-208 µg L(-1)) of the herbicide diuron. There was significant inhibition in the growth and biomass after the initial 7-day exposure (e.g. frond number EC50=59.2 and 52.2 µg L(-1) for L. minor and L. gibba, respectively). Following transfer to clean media, recovery (the highest concentration yielding no significant difference in the effect endpoint from the control) was observed for all effects endpoints at concentrations ranging 60-111 µg L(-1) for L. minor and 60-208 µg L(-1) for L. gibba. These results suggest that recovery is possible for primary producers at environmentally relevant concentrations considered significant in ecological risk assessment.

  4. Removal of {sup 99m}Tc and {sup 201}Tl by means of Lemna Gibba; Remocion de {sup 99m}Tc y {sup 201}Tl mediante Lemna Gibba

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez R, E.; Carreno de L, M. C.; Cuevas S, J. C.; Hernadez T, U. O. [Instituto Tecnologico de Toluca, Av. Tecnologico s/n, Fraccionamiento La Virgen, 52149 Metepec, Estado de Mexico (Mexico); Monroy G, F., E-mail: edelmiraf@yahoo.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2012-10-15

    In this work the capacity of the water macrophyte Lemna gibba coming from San Pedro Tultepec in the Mexico State was studied to remove the radioisotopes {sup 99m}Tc and {sup 201}Tl, in order to show the capacity of this macrophyte for to treat some radioactive waste flowing that could contain this radioisotopes type. The removal capacity of {sup 99m}Tc and {sup 201}Tl of the macrophyte Lemna gibba was determined using the batch method. In accordance with the values of the obtained K{sub d}, the Lemna gibba with a size of particle diameter among 1mm - 300 {mu}m presents a better adsorption of {sup 99m}Tc. The {sup 201}Tl is adsorbed better in the bioadsorbent when it has a size of particle diameter <150{mu}m. (Author)

  5. Exogenous salicylate application affects the lead and copper accumulation characteristics of Lemna gibba L.

    Energy Technology Data Exchange (ETDEWEB)

    Duman, Fatih; Aksoy, Ahmet; Ozturk, Fatma; Ceylan, Ahmet [Erciyes Univ., Kayseri (Turkey). Dept. of Biology

    2010-11-15

    Previous studies have shown that salicylates can change the ion permeability of root cells. Therefore the possible effects of exogenous salicylate application on lead (Pb) and copper (Cu) accumulation and its protective role against DNA damage due to metal exposure in Lemna gibba were studied. L. gibba was exposed to 5, 10, and 25 {mu}M Pb and Cu for six days in the presence and absence of sodium salicylate (SA) (0.1, 0.5, and 1 mM). At all concentrations tested, SA application decreased Pb accumulation. On the other hand, application of 0.5 mM SA increased Cu accumulation. SA did not reduce DNA damage resulting from Pb and Cu toxicity. In summary, SA may be useful for reducing Pb accumulation, and application of SA at 0.5 mM may be useful for the phytoextraction of Cu. (orig.)

  6. Aquatic microcosm assessment of the effects of tylosin on Lemna gibba and Myriophyllum spicatum

    Energy Technology Data Exchange (ETDEWEB)

    Brain, Richard A. [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, ON, N1G 2W1 (Canada); Bestari, Ketut [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, ON, N1G 2W1 (Canada); Sanderson, Hans [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, ON, N1G 2W1 (Canada); Hanson, Mark L. [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, ON, N1G 2W1 (Canada); Wilson, Christian J. [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, ON, N1G 2W1 (Canada); Johnson, David J. [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, ON, N1G 2W1 (Canada); Sibley, Paul K. [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, ON, N1G 2W1 (Canada); Solomon, Keith R. [Centre for Toxicology, Department of Environmental Biology, University of Guelph, Guelph, ON, N1G 2W1 (Canada)]. E-mail: ksolomon@uoguelph.ca

    2005-02-01

    Tylosin is a macrolide antibiotic commonly used for therapeutic treatment and prophylaxis in livestock. As part of a larger ecotoxicological study, the potential phytotoxic effects of tylosin on the rooted macrophyte Myriophyllum spicatum and the floating macrophyte Lemna gibba were assessed under semi-field conditions using 15 12000-L microcosms. Concentrations of 0, 10, 30, 300 {mu}g/L (n = 3), and 600, 1000, and 3000 {mu}g/L (n = 1) were evaluated as part of separate ANOVA and regression analyses over an exposure period of 35 days. Fate of tylosin was monitored over time in the highest three treatments, where dissipation followed pseudo-first order kinetics with associated half-lives ranging from 9 to 10 days. For both M. spicatum and L. gibba, tylosin was found to cause no biologically significant changes to any endpoint assessed compared to controls at a Type I error rate of 0.1. However, subsequent power analyses revealed that there was generally insufficient power to declare that there were no significant differences at a Type II error rate of 0.2. Conclusions concerning biologically significant impacts were therefore further assessed based on other statistical criteria including comparisons of percent differences between replicated treatments and controls, minimum significant and minimum detectable differences, and coefficients of variation. Based on these criteria, at an ecological effect size of >20% change, tylosin was concluded to elicit no biologically or ecologically significant toxicity to M. spicatum or L. gibba. A hazard quotient assessment indicated that tylosin poses little risk to either species of macrophyte, with an HQ value calculated to be nearly three orders of magnitude below 1 (0.002). - Tylosin is not expected to have ecologically significant effects on Ontario freshwater macrophytes.

  7. Toxic Effects of Nickel Oxide Bulk and Nanoparticles on the Aquatic Plant Lemna gibba L.

    Directory of Open Access Journals (Sweden)

    Abdallah Oukarroum

    2015-01-01

    Full Text Available The aquatic plant Lemna gibba L. was used to investigate and compare the toxicity induced by 30 nm nickel oxide nanoparticles (NiO-NPs and nickel(II oxide as bulk (NiO-Bulk. Plants were exposed during 24 h to 0–1000 mg/L of NiO-NPs or NiO-Bulk. Analysis of physicochemical characteristics of nanoparticles in solution indicated agglomerations of NiO-NPs in culture medium and a wide size distribution was observed. Both NiO-NPs and NiO-Bulk caused a strong increase in reactive oxygen species (ROS formation, especially at high concentration (1000 mg/L. These results showed a strong evidence of a cellular oxidative stress induction caused by the exposure to NiO. Under this condition, NiO-NPs and NiO-Bulk induced a strong inhibitory effect on the PSII quantum yield, indicating an alteration of the photosynthetic electron transport performance. Under the experimental conditions used, it is clear that the observed toxicity impact was mainly due to NiO particles effect. Therefore, results of this study permitted determining the use of ROS production as an early biomarker of NiO exposure on the aquatic plant model L. gibba used in toxicity testing.

  8. Oxygen and hydrogen isotope fractionation during cellulose metabolism in Lemna gibba L

    International Nuclear Information System (INIS)

    Yakir, D.; DeNiro, M.J.

    1990-01-01

    Lemna gibba L. B3 was grown under heterotrophic, photoheterotrophic, and autotrophic conditions in water having a variety of hydrogen and oxygen isotopic compositions. The slopes of the linear regression lines between the isotopic composition of water and leaf cellulose indicated that under the three growth conditions about 40, 70, and 100% of oxygens and carbon-bound hydrogens of cellulose exchanged with those of water prior to cellulose formation. Using the equations of the linear relationships, we estimated the overall fractionation factors between water and the exchanged oxygen and carbon bound-hydrogen of cellulose. At least two very different isotope effects must determine the hydrogen isotopic composition of Lemna cellulose. One reflects the photosynthetic reduction of NADP, while the second reflects exchange reactions that occur subsequent to NADP reduction. Oxygen isotopic composition of cellulose apparently is determined by a single type of exchange reaction with water. Under different growth conditions, variations in metabolic fluxes affect the hydrogen isotopic composition of cellulose by influencing the extent to which the two isotope effects mentioned above are recorded. The oxygen isotopic composition of cellulose is not affected by such changes in growth conditions

  9. Potentiation of aquatic pollution by ethylene glycol with regard to the aquatic angiosperm, Lemna gibba

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, D.A.; Barber, J.T.; Yatsu, L.Y.; Ensley, H.E. [Tulane Univ., New Orleans, LA (United States). Dept. of Ecology, Evolution and Organismal Biology

    1995-12-31

    Ethylene glycol is usually thought of as a benign component of urban runoff. Thus, its EC50 value, with regard to the vegetative growth of axenically grown Lemna gibba, is relatively high, viz. 164 mM. Ethylene glycol is not metabolized by Lemna but growth is demonstrably stimulated at concentrations below 75 mM. In the presence of ethylene glycol, the fronds of duckweed are dark green, translucent and the growth medium contains gas bubbles of carbon dioxide which result from an enhanced uptake of sucrose from the growth medium and its subsequent respiration. The uptake is a non-specific effect since the uptake of various other compounds, including water, is enhanced when duckweed is grown in the presence of ethylene glycol. The increased uptake of water, sucrose, inorganic ions and organic compounds results from an increased permeability due to the creation of intercellular holes in the aerenchymatous tissues of the ethylene glycol-treated plants. The mechanism by which ethylene glycol causes the holes is unknown but may involve a disruption in lipid metabolism since the hydrophobicity of the fronds is altered and their lipid composition is changed. The significance of this phenomenon is that toxicants, just like innocuous substances, are taken up in increased amounts by treated plants and as a result their toxicities are increased with regard to duckweed as evidenced by a decrease in their effective concentrations, often of more than 3-fold. These results suggest that although ethylene glycol itself may be benign, its presence in polluted waters containing other toxicants may potentiate the effects of those pollutants.

  10. Toxicity of 14 photooxidized anthracene derivatives to Lemna gibba L.G-3

    Energy Technology Data Exchange (ETDEWEB)

    Mallakin, A.; MacConkey, B.J.; McKibbenyen, B.; Sniekusyen, V.; Dixon, D.G.; Greenberg, B.M. [Univ. of Waterloo, Ontario (Canada)

    1995-12-31

    Phototoxicity of PAHs is known to occur via photosensitization reactions and potentially by photomodification of chemicals to more toxic species. The hazards enhancement of polycyclic aromatic hydrocarbon (PAHs) toxicity to plants by artificial light source and natural solar radiation has been recently demonstrated. Growth and chlorosis were used as end points to assess the photoinduced toxicity to 14 oxygenated anthracene derivatives to Lemna gibba. Reversed-phase liquid chromatography (HPLC) equipped with diode array detector was used as analytical technique for measurement of polycyclic aromatic hydrocarbons photomodification products and to study the modification kinetics. The toxicity bioassays were performed both under visible light and simulated solar radiation (SSR), which mimicked the relative load of UV + visible light in solar radiation. Comparative studies with visible and SSR showed that the phototoxicity of these chemicals was activated, with UV radiation being the most influenced spectral region in enhancing the harmful effects of the chemicals. Photomodified PAHs exhibited toxicity in visible light and increased toxicity in simulate solar radiation. The rates of photomodification of chemicals were quite different but rapid enough to contribute to toxicity. There was increase in inhibition of growth of plants, relative to control, with increasing in rate of photomodification of the oxygenated PAHs.

  11. Boron removal by the duckweed Lemna gibba: a potential method for the remediation of boron-polluted waters.

    Science.gov (United States)

    Del-Campo Marín, Claudia M; Oron, Gideon

    2007-12-01

    Boron (B) is often found in polluted and desalinated waters. Despite its potentially environmental damaging effects, efficient treatments are lacking. The duckweed Lemna gibba has been shown to remove toxic elements from water; however, its applicability to B removal is unknown. In this study, L. gibba was examined for its tolerance to B in water and its B removal efficiency. Duckweed plants were grown in outdoor 12-day batch experiments in nutrient solution containing 0.3-10 mg B L(-1). Plant biomass production was not affected by B over the tested concentrations during the 12-day cultivation period. Boron removal and the bioconcentration factor of B in L. gibba were highest at initial B concentrations below 2 mg L(-1), and decreased as the initial B concentration increased. Boron content in the plants at the end of the experiment ranged between 930 and 1900 mg kg(-1) dry weight, and was comparable to that of wetland plants reported to be good B accumulators. Boron removal by L. gibba may therefore be a suitable option for the treatment of water containing B concentrations below 2 mg L(-1).

  12. Toxicity and metabolism of 2,4-dichlorophenol by the aquatic angiosperm Lemna gibba

    Energy Technology Data Exchange (ETDEWEB)

    Ensley, H.E. (Tulane Univ., New Orleans, LA (United States). Dept. of Chemistry); Barber, J.T.; Polito, M.A.; Oliver, A.I. (Tulane Univ., New Orleans, LA (United States). Dept. of Ecology, Evolution, and Organismal Biology)

    1994-02-01

    The toxicity and metabolism of 2,4-dichlorophenol with regard to the aquatic macrophyte Lemna gibba (duckweed), have been studied. Toxicity is described in terms of the effect of 2,4-dichlorophenol (2,4-DCP) on the vegetative reproduction of duckweed over a 10-d growth period; the EC10 and EC50 were 2.5 and 9.2 [mu]M, respectively. Metabolism of 2,4-dichlorophenol was monitored by incubation of the plants with radiolabeled substrate, and periodic sampling and analysis by reversed-phase HPLC of the plant growth medium. Depending on the growth conditions, up to 95% of the 2,4-DCP was metabolized over a 6-d growth period. To analyze the metabolites, the plants were grown in the presence of sublethal concentrations of [U-[sup 14]C]-2,4-DCP. The growth medium was lyophilized and then mixed with the plants, extracted, and analyzed using reversed-phase HPLC, followed by scintillation counting of the fractions. The major metabolite was isolated and identified as 2,4-dichlorophenol-[beta]-D-glucopyranoside by high-field NMR and MS. The structure of the metabolite was confirmed by synthesis and by enzymatic cleavage of the [beta]-glucosidic linkage to afford 2,4-DCP. An important consequence of conjugate formation is the masking of the presence of 2,4-DCP to the usual analytical techniques used for its detection and quantitation. This finding is probably applicable to other contaminants and organisms.

  13. Bioaccumulation and toxicity assessment of irrigation water contaminated with boron (B) using duckweed (Lemna gibba L.) in a batch reactor system.

    Science.gov (United States)

    Türker, Onur Can; Yakar, Anıl; Gür, Nurcan

    2017-02-15

    The present study assesses ability of Lemna gibba L. using a batch reactor approach to bioaccumulation boron (B) from irrigation waters which were collected from a stream in largest borax reserve all over the world. The important note that bioaccumulation of B from irrigation water was first analyzed for first time in a risk assessment study using a Lemna species exposed to various B concentrations. Boron toxicity was evaluated through plant growth and biomass production during phytoremediation process. The result from the present experiment indicated that L. gibba was capable of removing 19-63% B from irrigation water depending upon contaminated level or initial concentration. We also found that B was removed from aqueous solution following pseudo second order kinetic model and Langmuir isotherm model better fitted equilibrium obtained for B phytoremediation. Maximum B accumulation in L. gibba was determined as 2088mgkg -1 at average inflow B concentration 17.39mgL -1 at the end of the experiment. Conversely, maximum bioconcentration factor obtained at lowest inflow B concentrations were 232 for L. gibba. The present study suggested that L. gibba was very useful B accumulator, and thus L. gibba-based techniques could be a reasonable phytoremediation option to remove B directly from water sources contaminated with B. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Influence of pH, light cycle, and temperature on ecotoxicity of four sulfonylurea herbicides towards Lemna gibba

    DEFF Research Database (Denmark)

    Rosenkrantz, Rikke Tjørnhøj; Cedergreen, Nina; Baun, Anders

    2013-01-01

    In chemical regulation, e.g. the EU Water Framework Directive, REACH, or the Pesticide Directive, standardized ecotoxicological tests are applied to evaluate and rank the hazard of compounds and for deriving environmental quality standards (EQS). Standardized test methods prescribe fixed testing...... conditions e.g. specific temperature, pH, light intensity etc. However, environmental conditions under which the organisms live are rarely identical to the standard conditions. Thus, the ecotoxicity of compounds found in standard test is not only a function of the compounds inherent physico...... test conditions on the toxicity of four sulfonylurea herbicides (SUs). The toxicity of the four SUs towards Lemna gibba was investigated at three pH levels (6, 7.5 and 9), at two temperatures (15 and 24 °C) and two light regimes (continuous and 12:12 h light:dark cycle) The EC50 increased twofold...

  15. A combination method based on chitosan adsorption and duckweed (Lemna gibba L.) phytoremediation for boron (B) removal from drinking water.

    Science.gov (United States)

    Türker, Onur Can; Baran, Talat

    2018-01-28

    The metalloid boron (B) and its compounds widely exist in the environment, and boron can have hazardous effects on plants, animals, and human beings when it is found in high concentrations in water bodies. It is difficult and costly to remove B with conventional treatment methods from drinking water. Therefore, alternative and cost-effective treatment techniques are necessary. In this study, for the first time, a novel and environmentally friendly method based on the phytoremediation ability of chitosan and duckweed (Lemna gibba L.) combination was evaluated for B removal from drinking water. Our results from batch adsorption experiment indicated that the highest B uptake capacity of chitosan bead was found as 3.18 mg/g, and we determined the optimal B sorption occurs at pH value of 7. The Langmuir isotherm and pseudo-second-order kinetic model better fitted the equilibrium obtained for B removal. B in drinking water could be reduced to less than 2.4 mg L -1 when 0.05 g of plant-based chitosan beads and 12 L. gibba fronds were used in the 4-day treatment period.

  16. Effect of soluble copper released from copper oxide nanoparticles solubilisation on growth and photosynthetic processes of Lemna gibba L.

    Science.gov (United States)

    Perreault, François; Samadani, Mahshid; Dewez, David

    2014-06-01

    Copper oxide nanoparticles (CuO NPs) are used as a biocide in paints, textiles and plastics. Their application may lead to the contamination of aquatic ecosystems, where potential environmental effects remain to be determined. Toxic effects may be related to interactions of NPs with cellular systems or to particles' solubilisation releasing metal ions. In this report, we evaluated CuO NPs and soluble copper effects on photosynthesis of the aquatic macrophyte Lemna gibba L to determine the role of particle solubility in NPs toxicity. When L. gibba plants were exposed 48 h to CuO NPs or soluble copper, inhibition of photosynthetic activity was found, indicated by the inactivation of Photosystem II reaction centers, a decrease in electron transport and an increase of thermal energy dissipation. Toxicity of CuO NPs was mainly driven by copper ions released from particles. However, the bioaccumulation of CuO NPs in plant was shown, indicating the need to evaluate organisms of higher trophic level.

  17. Evaluation of the effects of diuron and its derivatives on Lemna gibba using a fluorescence toxicity index.

    Science.gov (United States)

    Dewez, David; Marchand, Mathieu; Eullaffroy, Philippe; Popovic, Radovan

    2002-10-01

    The herbicide diuron (DCMU) [3-(3,4-dichlorophenyl)-1,1-dimethylurea] is largely used in agricultural practices which contribute to water pollution in large areas. Its degradation induced by light or microbial activity is known to be a slow process, and may result in the accumulation of DCMU derivatives in the environment. In this report we used the yield of PSII variable fluorescence of Lemna gibba affected by the DCMU derivatives DCPMU [1-(3,4-dichlorophenyl)-3-methylurea], DCPU [1-(3,4-dichlorophenyl)urea], and DCA [3,4-dichloroaniline] to calculate the fluorescence toxicity index. We found the fluorescence toxicity index to be a useful parameter to evaluate the inhibitory effect on PSII electron transport in L. gibba exposed to DCMU and its derivatives. The variations observed for the inhibitory effect between DCMU and its derivatives seem to be caused by the modification of the dimethylurea group within the DCMU molecule. The fluorescence toxicity index demonstrated a strong quantitative dependency between the inhibitory effect of PSII electron transport and pollutant concentrations. We propose the fluorescence toxicity index to be a useful tool for future bioassays in evaluating the quality of water polluted with herbicides that induce an inhibition to PSII photochemistry. Copyright 2002 Wiley Periodicals, Inc.

  18. Evaluation and application of an innovative method based on various chitosan composites and Lemna gibba for boron removal from drinking water.

    Science.gov (United States)

    Türker, Onur Can; Baran, Talat

    2017-06-15

    Boron exists in various types of water environments, and it is difficult and costly to remove B with conventional treatment methods from drinking water. Clearly, alternative and cost effective treatment techniques are imperative. In the present study, an innovative and environment friendly method based on hybrid systems consisting of various chitosan composite beads and Lemna gibba were evaluated for removal of B from drinking water. Our results from batch adsorption experiment indicated that a plant-based chitosan composite bead has a higher capacity of B removal than mineral-based chitosan composite beads. Almost 50% of total B removal was achieved using the hybrid system based on dried Lemna-chitosan composite beads and Lemna gibba combination in 4 days. Even at the high B concentration (8mgBL -1 ), B in drinking water could be reduced to less than 2.4mgL -1 when 0.05g plant-based chitosan composite beads and 12 Lemna fronds were used for 50mL test solution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Efecto del fotoperiodo en la remoción de plomo por Lemna gibba L. (Lemnaceae

    Directory of Open Access Journals (Sweden)

    Guadalupe Miranda

    2015-08-01

    Full Text Available El plomo llega a las aguas provenientes de las industrias de baterías, soldaduras, pinturas, etc. causando daños a los seres vivos, por lo que es necesario promover el desarrollo de tecnologías que ayuden a mejorar la calidad de los efluentes y que al mismo tiempo sean adecuadas al contexto socioeconómico del país. En este trabajo se plantea el uso de una angiosperma acuática, la especieLemna gibbade la familia Lemnaceae que tiene un crecimiento exponencial y su cultivo es fácil en laboratorio. Para absorber el plomo (PbNO32 se prepararon cinco concentraciones, a nivel de bioensayo en el laboratorio y bajo el efecto de dos diferentes condiciones de fotoperiodo (luz continua y 12 h luz/12 h oscuridad durante cuatro días, ya que a partir de este día libera el Pb al medio. Los resultados indican que en las dos concentraciones de Pb más bajas (30 y 50 mgl-1, el fotoperiodo 12/12 es más favorable para su absorción (9405 µgl-1más y 18,895 µgl-1 más respectivamente mientras que en las tres restantes (100, 200 y 300 mgl-1 lo fue la condición de luz continua. (6600 µgl-1, 1949 µgl-1, 5587 µgl-1 más respectivamente. Los conocimientos que se derivan de este estudio, permiten optimizar el uso deL. gibbaen el tratamiento terciario de aguas residuales.

  20. Comparison of salicylic acid, benzoic acid and p-hydroxybenzoic acid for their ability to induce flowering in Lemna Gibba G3

    International Nuclear Information System (INIS)

    Cleland, F.C.; Kang, B.G.; Khurana, J.P.

    1986-01-01

    The long-day plant Lemna gibba G3 fails to flower under continuous light on NH 4 + -free 0.5 H medium. This inhibition is completely reversed by 10 μM salicyclic acid (SA) or 32 μM benzoic acid (BA). By contrast, p-hydroxybenzoic acid (p-OH-BA) has virtually no effect on flowering at levels as high as 320 μM. Uptake rates for the three compounds are comparable. Competition studies using 14 C-SA indicate that, compared to SA, BA is about 10-fold less effective and p-OH-BA is nearly 100-fold less effective in competing against 14 C-SA uptake. Both the effectiveness of SA for inducing flowering and the uptake of 14 C-SA are substantially increased as the pH of the medium is lowered from 8 to 4.5. Under a nitrogen atmosphere the uptake of 14 C-SA is partially inhibited above pH 5. Phosphate metabolism may be important for flowering since increasing the phosphate level in the medium 10-15 fold results in substantial flowering, and suboptimal levels of Sa and phosphate interact synergistically to stimulate flowering. The interaction of phosphate with BA and p-OH-BA will be presented

  1. Effects of Homeopathic Arsenicum Album, Nosode, and Gibberellic Acid Preparations on the Growth Rate of Arsenic-Impaired Duckweed (Lemna gibba L.

    Directory of Open Access Journals (Sweden)

    Tim Jäger

    2010-01-01

    Full Text Available This study evaluated the effects of homeopathically potentized Arsenicum album, nosode, and gibberellic acid in a bioassay with arsenic-stressed duckweed (Lemna gibba L.. The test substances were applied in nine potency levels (17x, 18x, 21x–24x, 28x, 30x, 33x and compared with controls (unsuccussed and succussed water regarding their influence on the plant’s growth rate. Duckweed was stressed with arsenic(V for 48 h. Afterwards, plants grew in either potentized substances or water controls for 6 days. Growth rates of frond (leaf area and frond number were determined with a computerized image analysis system for different time intervals (days 0–2, 2–6, 0–6. Five independent experiments were evaluated for each test substance. Additionally, five water control experiments were analyzed to investigate the stability of the experimental setup (systematic negative control experiments. All experiments were randomized and blinded. The test system exhibited a low coefficient of variation (≈1%. Unsuccussed and succussed water did not result in any significant differences in duckweed growth rate. Data from the control and treatment groups were pooled to increase statistical power. Growth rates for days 0–2 were not influenced by any homeopathic preparation. Growth rates for days 2–6 increased after application of potentized Arsenicum album regarding both frond area (p < 0.001 and frond number (p < 0.001, and by application of potentized nosode (frond area growth rate only, p < 0.01. Potencies of gibberellic acid did not influence duckweed growth rate. The systematic negative control experiments did not yield any significant effects. Thus, false-positive results can be excluded with high certainty. To conclude, the test system with L. gibba impaired by arsenic(V was stable and reliable. It yielded evidence for specific effects of homeopathic Arsenicum album preparations and it will provide a valuable tool for future experiments that aim at

  2. Comparing the acute sensitivity of growth and photosynthetic endpoints in three Lemna species exposed to four herbicides.

    Science.gov (United States)

    Park, Jihae; Brown, Murray T; Depuydt, Stephen; Kim, Jang K; Won, Dam-Soo; Han, Taejun

    2017-01-01

    An ecological impact assessment of four herbicides (atrazine, diuron, paraquat and simazine) was assessed using the aquatic floating vascular plants, Lemna gibba, Lemna minor and Lemna paucicostata as test organisms. The sensitivity of several ecologically relevant parameters (increase in frond area, root length after regrowth, maximum and effective quantum yield of PSII and maximum electron transport rate (ETR max ), were compared after a 72 h exposure to herbicides. The present test methods require relatively small sample volume (3 mL), shorter exposure times (72 h), simple and quick analytical procedures as compared with standard Lemna assays. Sensitivity ranking of endpoints, based on EC 50 values, differed depending on the herbicide. The most toxic herbicides were diuron and paraquat and the most sensitive endpoints were root length (6.0-12.3 μg L -1 ) and ETR max (4.7-10.3 μg L -1 ) for paraquat and effective quantum yield (6.8-10.4 μg L -1 ) for diuron. Growth and chlorophyll a fluorescence parameters in all three Lemna species were sensitive enough to detect toxic levels of diuron and paraquat in water samples in excess of allowable concentrations set by international standards. CV values of all EC 50 s obtained from the Lemna tests were in the range of 2.8-24.33%, indicating a high level of repeatability comparable to the desirable level of herbicides in aquatic ecosystems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Growth inhibition and recovery of Lemna gibba after pulse exposure to sulfonylurea herbicides

    DEFF Research Database (Denmark)

    Rosenkrantz, Rikke Tjørnhøj; Baun, Anders; Kusk, Kresten Ole

    2013-01-01

    The exposure of non-target aquatic organisms to pesticides often happens as short-term, high exposure events (pulses) and effects of these must be addressed in the current regulation in the EU. It is, however, questionable whether the effects of pulse exposures are adequately covered by the stand......The exposure of non-target aquatic organisms to pesticides often happens as short-term, high exposure events (pulses) and effects of these must be addressed in the current regulation in the EU. It is, however, questionable whether the effects of pulse exposures are adequately covered...... by the standardized ecotoxicological tests used in environmental effect assessments, since these aim at maintaining constant exposure concentrations during the incubation. Therefore, we investigated the effects of four sulfonylurea herbicides (flupyrsulfuron-methyl, metsulfuron-methyl, rimsulfuron, and thifensulfuron...... tests. The approach of this study enables experimentally based comparisons between observations of effects between the two exposure regimes. We propose that results obtained in this way be applied in effect assessments for intermittent releases....

  4. Functional analysis of a Lemna gibba rbcS promoter regulated by ...

    Indian Academy of Sciences (India)

    2013-04-12

    Apr 12, 2013 ... controlled expression of a foreign gene using the chalcone syn- thase promoter in tobacco BY-2 cells. J. Ferment. Bioeng. 86,. 317–323. Laby R. J., Kincaid M. S., Kim D. and Gibson S. I. 2000. The Arabidopsis sugar-insensitive mutants sis4 and sis5 are defective in abscisic acid synthesis and response.

  5. Rhizobium lemnae sp. nov., a bacterial endophyte of Lemna aequinoctialis.

    Science.gov (United States)

    Kittiwongwattana, Chokchai; Thawai, Chitti

    2014-07-01

    Bacterial strain L6-16(T) was isolated from Lemna aequinoctialis. Cells were Gram-stain-negative, rod-shaped and motile with monopolar flagella. The phylogenetic analysis of its nearly complete 16S rRNA gene sequence revealed that strain L6-16(T) was a member of the genus Rhizobium. Its closest relative was Rhizobium tarimense PL-41(T) with a 16S rRNA gene sequence similarity value of 98.3%. Sequence similarity analysis of the housekeeping recA and atpD genes showed low levels of sequence similarity (Rhizobium. Strain L6-16(T) was able to grow between pH 5 and 11 (optimum 7.0) and at temperatures ranging from 20 to 41 °C (optimum 30 °C). It tolerated NaCl up to 1 % (w/v) (optimum 0.5%). C18 : 1ω7c and/or C18 :  1ω6c (summed feature 8; 79.5%) were found as predominant cellular fatty acids. The DNA G+C content of strain L6-16(T) was 58.1 mol% (Tm). Based on low levels of DNA-DNA relatedness, strain L6-16(T) was distinct from members of phylogenetically related species including R. tarimense PL-41(T) (38.3 ± 0.8%), Rhizobium rosettiformans W3(T) (6.9 ± 0.4%) and Rhizobium pseudoryzae J3-A127(T) (12.3 ± 0.6 %). Strain L6-16(T) was unable to nodulate the roots of Phaseolus vulgaris, and nodC and nifH genes were not detected. The results obtained from phylogenetic analyses, phenotypic characterization and DNA-DNA hybridization indicated that strain L6-16(T) represents a novel species of the genus Rhizobium, for which the name Rhizobium lemnae sp. nov. is proposed. The type strain is L6-16(T) ( = NBRC 109339(T) = BCC 55143(T)). © 2014 IUMS.

  6. Genome-wide analysis of adaptive molecular evolution in the carnivorous plant Utricularia gibba.

    Science.gov (United States)

    Carretero-Paulet, Lorenzo; Chang, Tien-Hao; Librado, Pablo; Ibarra-Laclette, Enrique; Herrera-Estrella, Luis; Rozas, Julio; Albert, Victor A

    2015-01-09

    The genome of the bladderwort Utricularia gibba provides an unparalleled opportunity to uncover the adaptive landscape of an aquatic carnivorous plant with unique phenotypic features such as absence of roots, development of water-filled suction bladders, and a highly ramified branching pattern. Despite its tiny size, the U. gibba genome accommodates approximately as many genes as other plant genomes. To examine the relationship between the compactness of its genome and gene turnover, we compared the U. gibba genome with that of four other eudicot species, defining a total of 17,324 gene families (orthogroups). These families were further classified as either 1) lineage-specific expanded/contracted or 2) stable in size. The U. gibba-expanded families are generically related to three main phenotypic features: 1) trap physiology, 2) key plant morphogenetic/developmental pathways, and 3) response to environmental stimuli, including adaptations to life in aquatic environments. Further scans for signatures of protein functional specialization permitted identification of seven candidate genes with amino acid changes putatively fixed by positive Darwinian selection in the U. gibba lineage. The Arabidopsis orthologs of these genes (AXR, UMAMIT41, IGS, TAR2, SOL1, DEG9, and DEG10) are involved in diverse plant biological functions potentially relevant for U. gibba phenotypic diversification, including 1) auxin metabolism and signal transduction, 2) flowering induction and floral meristem transition, 3) root development, and 4) peptidases. Taken together, our results suggest numerous candidate genes and gene families as interesting targets for further experimental confirmation of their functional and adaptive roles in the U. gibba's unique lifestyle and highly specialized body plan. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  7. High Gene Family Turnover Rates and Gene Space Adaptation in the Compact Genome of the Carnivorous Plant Utricularia gibba.

    Science.gov (United States)

    Carretero-Paulet, Lorenzo; Librado, Pablo; Chang, Tien-Hao; Ibarra-Laclette, Enrique; Herrera-Estrella, Luis; Rozas, Julio; Albert, Victor A

    2015-05-01

    Utricularia gibba is an aquatic carnivorous plant with highly specialized morphology, featuring fibrous floating networks of branches and leaf-like organs, no recognizable roots, and bladder traps that capture and digest prey. We recently described the compressed genome of U. gibba as sufficient to control the development and reproduction of a complex organism. We hypothesized intense deletion pressure as a mechanism whereby most noncoding DNA was deleted, despite evidence for three independent whole-genome duplications (WGDs). Here, we explore the impact of intense genome fractionation in the evolutionary dynamics of U. gibba's functional gene space. We analyze U. gibba gene family turnover by modeling gene gain/death rates under a maximum-likelihood statistical framework. In accord with our deletion pressure hypothesis, we show that the U. gibba gene death rate is significantly higher than those of four other eudicot species. Interestingly, the gene gain rate is also significantly higher, likely reflecting the occurrence of multiple WGDs and possibly also small-scale genome duplications. Gene ontology enrichment analyses of U. gibba-specific two-gene orthogroups, multigene orthogroups, and singletons highlight functions that may represent adaptations in an aquatic carnivorous plant. We further discuss two homeodomain transcription factor gene families (WOX and HDG/HDZIP-IV) showing conspicuous differential expansions and contractions in U. gibba. Our results 1) reconcile the compactness of the U. gibba genome with its accommodation of a typical number of genes for a plant genome, and 2) highlight the role of high gene family turnover in the evolutionary diversification of U. gibba's functional gene space and adaptations to its unique lifestyle and highly specialized body plan. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. The Metagenome of Utricularia gibba's Traps: Into the Microbial Input to a Carnivorous Plant

    Science.gov (United States)

    Alcaraz, Luis David; Martínez-Sánchez, Shamayim; Torres, Ignacio; Ibarra-Laclette, Enrique; Herrera-Estrella, Luis

    2016-01-01

    The genome and transcriptome sequences of the aquatic, rootless, and carnivorous plant Utricularia gibba L. (Lentibulariaceae), were recently determined. Traps are necessary for U. gibba because they help the plant to survive in nutrient-deprived environments. The U. gibba's traps (Ugt) are specialized structures that have been proposed to selectively filter microbial inhabitants. To determine whether the traps indeed have a microbiome that differs, in composition or abundance, from the microbiome in the surrounding environment, we used whole-genome shotgun (WGS) metagenomics to describe both the taxonomic and functional diversity of the Ugt microbiome. We collected U. gibba plants from their natural habitat and directly sequenced the metagenome of the Ugt microbiome and its surrounding water. The total predicted number of species in the Ugt was more than 1,100. Using pan-genome fragment recruitment analysis, we were able to identify to the species level of some key Ugt players, such as Pseudomonas monteilii. Functional analysis of the Ugt metagenome suggests that the trap microbiome plays an important role in nutrient scavenging and assimilation while complementing the hydrolytic functions of the plant. PMID:26859489

  9. The Metagenome of Utricularia gibba's Traps: Into the Microbial Input to a Carnivorous Plant.

    Directory of Open Access Journals (Sweden)

    Luis David Alcaraz

    Full Text Available The genome and transcriptome sequences of the aquatic, rootless, and carnivorous plant Utricularia gibba L. (Lentibulariaceae, were recently determined. Traps are necessary for U. gibba because they help the plant to survive in nutrient-deprived environments. The U. gibba's traps (Ugt are specialized structures that have been proposed to selectively filter microbial inhabitants. To determine whether the traps indeed have a microbiome that differs, in composition or abundance, from the microbiome in the surrounding environment, we used whole-genome shotgun (WGS metagenomics to describe both the taxonomic and functional diversity of the Ugt microbiome. We collected U. gibba plants from their natural habitat and directly sequenced the metagenome of the Ugt microbiome and its surrounding water. The total predicted number of species in the Ugt was more than 1,100. Using pan-genome fragment recruitment analysis, we were able to identify to the species level of some key Ugt players, such as Pseudomonas monteilii. Functional analysis of the Ugt metagenome suggests that the trap microbiome plays an important role in nutrient scavenging and assimilation while complementing the hydrolytic functions of the plant.

  10. Phenolic compounds of ethanol extracts of Lemna minor L., Lemna trisulca L. and Lemna polyrrhiza L. Schleid and their immunomodulating activity

    Directory of Open Access Journals (Sweden)

    Sergazy M. Adekenov

    2017-01-01

    Full Text Available The purpose of the study is to determine the composition of the phenolic compounds of ethanol extracts isolated from three species of duckweed: Lemna minor L., Lemna trisulca L. and Lemna polyrrhiza L. (the synonym is Spirodella polyrrhiza Schleid. and to study its effect on immune system activation.Materials and methods. The objects of the study are: air-dried grass samples of Lemna minor L., Lemna trisuica L. and Lemna polyrrhiza L. collected during their growing season in 2010–2011 in low-flow and stagnant ponds of Kozhevnikovsky and Tomsk districts of Tomsk region. Isolation of polyphenolic complexes (PFC was carried out by extraction of air-dried raw material with ethyl alcohol. In qualitative and quantitative analysis of the samples studied the method of reversed-phase high-performance liquid chromatography on an Agilent 1100 Series instrument (USA was used in isocratic mode. In the experiments, 200 male C57BL / 6 and BALB / C mice aged 8–12 weeks were used to determine immunomodulatory activity. Cell proliferation was assessed by a colorimetric method. The absorption of the obtained solutions was measured with a multi-channel spectrophotometer at the wavelength of 540 nm. The determination of antibody-forming cells in the spleen was performed by local hemolysis. The titer of antibodies in serum was evaluated in the hemagglutination reaction. The local hypersensitivity reaction of immediate type was assessed by the author’s modification.Results. For the first time the study of the qualitative composition and quantitative content of PFC of Lemna minor L. (LM , Lemna trisulca L. (LT trisulkas, and Lemna polyrrhiza L. (LP : (4,7 ± 0,4%, (3,3 ± 0,3%, (12,8 ± 0,7% was carried out. The highest content of phenolic acids (10,76% and the sum of flavonoids, isoflavonoids and coumarins (14,7% were found in the LP sample. The content of chlorogenic and 3,5-dihydroxybenzoic acids was 2–9 times higher in LP than in other species of duckweed

  11. Analyzing shell size variability in the opportunistic bivalve Corbula gibba: comparing Recent and fossil data

    Science.gov (United States)

    Tomášových, Adam; Fuksi, Tomáš; Zuschin, Martin

    2017-04-01

    Corbula gibba is a first-order opportunistic bivalve species presently inhabiting the Eastern Atlantic and Mediterranean. This species is abundant in fossil benthic assemblages in Middle Miocene sediments of the Central Paratethys (Vienna and Danube Basins). Its indicator value for interpretation of past environmental conditions remains poorly explored and requires studies combining paleoecological, taphonomic, sclerochronological, and allometric approaches. First, meta-analysis of published abundance and body size patterns in living assemblages collected in the Adriatic Sea revealed that in spite of the westward increase in primary productivity in the northern Adriatic Sea, size structure of living assemblages of C. gibba during the 20th century does not differ between the northeastern (mesotrophic) and northwestern (eutrophic) coasts Adriatic Sea, with size-frequency distributions showing minimal differences in maximum shell size. Second, samples from cores from the northern Adriatic that span the past centuries to few millennia show that past populations of C. gibba inhabiting northeastern Adriatic had significantly smaller sizes than today, suggesting that the lack of size differences in the 20th century is a relatively young phenonemon triggered by recent eutrophication events. However, population densities are still significantly higher on the western side of the Adriatic Sea and in the Gulf of Trieste. Third, a broad-scale macroecological comparison of size-frequency distributions of molluscan assemblages with dominant C. gibba from the eastern Mediterranean (Israel) shows significantly smaller shells, relative to larger shells from the Adriatic Sea. This increase in shell size correlates positively with an increase in chlorophyll concentrations. We observed a size gradient of similar magnitude in Middle Miocene assemblages with C. gibba between the Vienna and Danube basins. Fossil C. gibba shells size from the northeastern margin of the Danube Basin

  12. C_14 Oxylipin glucosides isolated from Lemna paucicostata

    OpenAIRE

    Kai, Kenji; Akaike, Ryota; Iida, Kanae; Yokoyama, Mineyuki; Watanabe, Naoharu

    2010-01-01

    Oxylipin glucosides (2−4) were isolated from Lemna paucicostata, with their structuresand absolute configurations elucidated by spectroscopic and chemical methods.Compounds 2−4 were glucosides of C14-oxylipin which were synthesized fromα-linolenic acid via the 9-lipoxygenase pathway.

  13. C14-oxylipin glucosides isolated from Lemna paucicostata.

    Science.gov (United States)

    Kai, Kenji; Akaike, Ryota; Iida, Kanae; Yokoyama, Mineyuki; Watanabe, Naoharu

    2010-07-01

    Oxylipin glucosides (2-4) were isolated from Lemna paucicostata with their structures and absolute configurations elucidated by spectroscopic and chemical methods. Compounds 2-4 were glucosides of C14 oxylipin which were synthesized from alpha-linolenic acid via the 9-lipoxygenase pathway. 2010 Elsevier Ltd. All rights reserved.

  14. Remediation of eutrophic water using Lemna minor in a controlled ...

    African Journals Online (AJOL)

    The growth response of common duckweed Lemna minor was studied at various temperature and pH levels for its possible application for remediating eutrophic waters. The dry weight, chlorophyll a, nitrogen, phosphorus, potassium, peroxidase (POD), catalase (CAT) and malondialdehyde (MDA) levels were determined.

  15. A new taxon in the Infundibulicybe gibba complex (Basidiomycota, Agaricales, Tricholomataceae) from Sardinia (Italy).

    Science.gov (United States)

    Vizzini, Alfredo; Contu, Marco; Musumeci, Enzo; Ercole, Enrico

    2011-01-01

    A new species of Infundibulicybe (viz. I. mediterranea sp. nov.) is described from Sardinia based both on morphological and molecular ITS data. The species, a close ally of I. gibba, differs from the latter in the darker tinges of the basidiomata, the stipe, which is nearly concolorous with the pileus, and smaller basidiospores. Drawings of the main micro-morphological features as well as a color photograph of fresh basidiomata in situ are provided.

  16. Potential for chromium (VI) bioremediation by the aquatic carnivorous plant Utricularia gibba L. (Lentibulariaceae).

    Science.gov (United States)

    Augustynowicz, Joanna; Łukowicz, Krzysztof; Tokarz, Krzysztof; Płachno, Bartosz Jan

    2015-07-01

    The aquatic carnivorous plant Utricularia gibba has one of the smallest known genomes among flowering plants, and therefore, it is an excellent model organism for physiological and developmental studies. The main aim of our work was to check whether the ubiquitous U. gibba might be useful for the phytoremediation of the highly toxic and mobile hexavalent chromium in waters. Plants were incubated for 1 week in a 50 μM (2.6 mg dm(-3)) Cr(VI) solution in laboratory conditions. Our results revealed that the plant exhibits a very high accumulation capacity for Cr. The accumulation level was higher than 780 mg kg(-1) and a bioconcentration factor >300. On the other hand, the plants showed a low tolerance to the elevated Cr concentration, which was expressed in a significant decrease of the photosystem II activity. However, the most pronounced negative influence of chromate was found on the morphology and activity of the traps. Due to its high accumulation capacity, we suggest that U. gibba may be efficient in the removal of chromate over a short time scale. It can also provide a new molecular resource for studying the mechanisms of Cr(VI) detoxification.

  17. Can we effectively degrade microcystins? - Implications on human health

    DEFF Research Database (Denmark)

    de la Cruz, Armah A; Antoniou, Maria; Hiskia, Anastasia

    2011-01-01

    Microcystins are cyclic heptapeptide toxins produced by a number of genera of cyanobacteria. They are ubiquitous in bodies of water worldwide and pose significant hazard to human, plant, and animal health. Microcystins are primarily hepatotoxins known to inhibit serine-threonine phosphatases...... leading to the disruption of cascade of events important in the regulation and control of cellular processes. Covalent binding of microcystins with phosphatases is thought to be responsible for the cytotoxic and genotoxic effects of microcystins. In addition, microcystins can trigger oxidative stress...... contact or inhalation to microcystins is now recognized to cause a wide range of acute illnesses which can be life-threatening. Microcystins are primarily degraded by microorganisms in the environment, while sunlight can cause the isomerization of the double bonds and hydroxylation in the presence...

  18. Microbial activity and bacterial community structure during degradation of microcystins

    DEFF Research Database (Denmark)

    Christoffersen, K.; Lyck, Susanne; Winding, A.

    2002-01-01

    experiment to evaluate the effects of organic lysates on bacterial proliferation in the absence of microcystin. An exponential decline of the dissolved toxins was observed in all cases with toxins present, and the degradation rates ranged between 0.5 and 1.0 d(-1). No lag phases were observed but slow......Degradation of realistic microcystin concentrations in lake water with indigenous bacteria was studied in laboratory and field experiments following inoculation with lysed toxic algal material containing microcystin primarily from Microcystis sp. or purified commercial microcystin-LR to microcosms....... It was hypothesised that the bacterial community from a lake with frequent occurrence of toxic cyanobacteria can degrade microcystin along with other organic compounds. The initial dissolved microcystin concentrations ranged between 10 and 136 mug 1(-1) (microcystin-LR equivalents) in the laboratory experiment, using...

  19. Effect of thermal pre-treatment on co-digestion of duckweed (Lemna gibba) and waste activated sludge on biogas production.

    Science.gov (United States)

    Gaur, Rubia Zahid; Khan, Abid Ali; Suthar, Surindra

    2017-05-01

    The duckweeds (DW) are considered as a major problem in tropical aquatic system as they grow very fast and produce enormous rich-biomass, which can be harvested for renewable energy operations. But complex lignocellulosic compounds limit their utility in process like anaerobic digestion. This batch study aimed to analyse characteristics (proximate, ultimate and physico-chemical) and possible utility of DW for anaerobic co-digestion with waste activated sludge (WAS) under mesophilic conditions for 35 d. Two sets of experiment were tested: substrate with and without thermal pre-treatment. Five combinations of DW: WAS (70:20, 60:20, 50:20, 40:20 and 30:20%) were established and biomethanation along with changes in pH, volatile solids (VS), volatile fatty acids (VFAs), and soluble chemical oxygen demand (sCOD) of digestate were recorded. The total CH 4 yield (mL CH 4 g -1 VS) ranged between 60 and 468 for pre-treated, and 9 and 76 for non-pre-treated. The maximum CH 4 yield was 468 mL CH 4 g -1 VS in DW: WAS (50:20). Thermally treated setups, showed about 13-, 24.1-, 21.1-, 1.4-, and 2.3-fold higher CH 4 than non-treated setups. The treated mixtures showed high reduction of S COD (>41-96) and VS (>59-98%) in co-digesters. The high degree of Gompertz curve fitting (R 2  > 0.99) has suggested pre-treatment of substrate for optimal outputs of co-digester. Based on results obtained, it is suggested that DW (50-60% in digester) can be used as renewable energy resource for biomethanation process after thermal pre-treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Microcystin-LR Induced Immunotoxicity in Mammals

    Directory of Open Access Journals (Sweden)

    Yaqoob Lone

    2016-01-01

    Full Text Available Microcystins are toxic molecules produced by cyanobacterial blooms due to water eutrophication. Exposure to microcystins is a global health problem because of its association with various other pathological effects and people all over the world are exposed to microcystins on a regular basis. Evidence shows that microcystin-LR (MC-LR may adversely affect the immune system, but its specific effects on immune functions are lacking. In the present review, immunotoxicological effects associated with MC-LR in animals, humans, and in vitro models have been reported. Overall, the data shows that chronic exposure to MC-LR has the potential to impair vital immune responses which could lead to increased risk of various diseases including cancers. Studies in animal and in vitro models have provided some pivotal understanding into the potential mechanisms of MC-LR related immunotoxicity suggesting that further investigation, particularly in humans, is required to better understand the relationship between development of disease and the MC-LR exposure.

  1. Microbial activity and bacterial community structure during degradation of microcystins

    DEFF Research Database (Denmark)

    Christoffersen, K.; Lyck, Susanne; Winding, A.

    2002-01-01

    . It was hypothesised that the bacterial community from a lake with frequent occurrence of toxic cyanobacteria can degrade microcystin along with other organic compounds. The initial dissolved microcystin concentrations ranged between 10 and 136 mug 1(-1) (microcystin-LR equivalents) in the laboratory experiment, using...... initial degradation rates occurred in 2 out of 7 cases, Microcystin was almost eliminated from the water after around 8 d. Results from concomitant measurements of bacterial abundance and net production showed an elevated bacterial activity within 1 to 2 d after the inoculation with algal lysates...

  2. Prey composition in the carnivorous plants Utricularia inflata and U. gibba (Lentibulariaceae) from Paria Peninsula, Venezuela

    OpenAIRE

    Elizabeth Gordon; Sergio Pacheco

    2007-01-01

    Las plantas carnívoras acuáticas del género Utricularia (Lentibulariaceae), capturan pequeños organismos acuáticos, como rotíferos, copépodos, y cladóceros, por medio de estructuras anatómicas semejantes a vesículas. Este estudio tuvo como objetivo determinar el tamaño y tipo de presas de U. gibba y U. inflata, recolectados en un pequeño lago y en un pastizal inundado, respectivamente, en la localidad de la Península de Paria (Estado Sucre, Venezuela). La acidez, conductividad, cantidad de ox...

  3. Prey composition in the carnivorous plants Utricularia inflata and U. gibba (Lentibulariaceae) from Paria Peninsula, Venezuela.

    Science.gov (United States)

    Gordon, Elizabeth; Pacheco, Sergio

    2007-01-01

    Carnivorous aquatic plants, genus Utricularia (Lentibulariaceae), capture small aquatic organisms, such as rotifers, copepods, and cladocerans, by means of anatomical structures named bladders. The present study aimed to determine prey size and composition in U. gibba and U inflata, which were collected from a small lake and an herbaceous wetland, respectively, located in Paria Peninsula (Sucre State, Venezuela). Water pH, conductivity, dissolved oxygen, and salinity were measured in situ at each sampling location, and water samples were collected to determine N-Kjeldahl, total-P, Na+, K+, Ca++, Mg++, and Cl-. Fifty bladders from each plant species were measured and their contents were analyzed. N-Kjeldahl and total-P values were similar in both sites, and were also similar to values reported for eutrophic ecosystems, although Na+, K+, Ca++, Mg++ concentrations and in situ water parameter values were higher in the herbaceous wetland. Bladder content showed the following zooplankton groups: rotifers, cladocerans, copepods, annelids, rhizopodeans, and insects; and the following phytoplankton divisions: Bacillariophyta, Chlorophyta, Cyanophyta, and Euglenophyta. U. inflata presented smaller and fewer bladders, but higher abundance and total algal and animal morphospecies richness than U. gibba. Prey composition similarity at the taxon level between the two carnivorous species was low.

  4. Monitoring of microcystin-LR in Luvuvhu River catchment ...

    African Journals Online (AJOL)

    The main aim of this study is to assess the levels of microcystin-LR in Luvuvhu River catchment and to assess the physicochemical parameters that may promote the growth of cyanobacteria. The level of microcystin-LR in some of the sampling sites was <0.18 ìg/l except for one site (Luvuvhu River just before the confluence ...

  5. Microcystin-LR equivalent concentrations in fish tissue during a ...

    African Journals Online (AJOL)

    The effects of a decomposing cyanobacteria bloom on water quality and the accumulation of microcystin-LR equivalent toxin in fish at Loskop Dam were studied in May 2012. Enzyme-linked immunosorbent assay [ELISA] was used to confirm the presence of microcystin-LR equivalent in the water and to determine the ...

  6. Can we effectively degrade microcystins? - Implications on human health

    DEFF Research Database (Denmark)

    de la Cruz, Armah A; Antoniou, Maria; Hiskia, Anastasia

    2011-01-01

    Microcystins are cyclic heptapeptide toxins produced by a number of genera of cyanobacteria. They are ubiquitous in bodies of water worldwide and pose significant hazard to human, plant, and animal health. Microcystins are primarily hepatotoxins known to inhibit serine-threonine phosphatases...... in cells resulting in necrosis or apoptosis. Their cyclic structure and novel amino acids enhance their stability and persistence in the environment. Humans are primarily exposed to microcystins via drinking water consumption and accidental ingestion of recreational water. Recreational exposure by skin...... contact or inhalation to microcystins is now recognized to cause a wide range of acute illnesses which can be life-threatening. Microcystins are primarily degraded by microorganisms in the environment, while sunlight can cause the isomerization of the double bonds and hydroxylation in the presence...

  7. Possible ecological risk of two pharmaceuticals diclofenac andparacetamol demonstrated on a model plant Lemna minor

    Czech Academy of Sciences Publication Activity Database

    Kummerová, M.; Zezulka, Š.; Babula, P.; Tříska, Jan

    2016-01-01

    Roč. 302, jan (2016), s. 351-361 ISSN 0304-3894 Institutional support: RVO:67179843 Keywords : Antioxidant mechanism * Diclofenac * Lemna minor * Oxidative stress * Paracetamol Subject RIV: EH - Ecology, Behaviour Impact factor: 6.065, year: 2016

  8. EKOGENOTOKSISITAS LIMBAH CAIR BATIK DAN EFEK ANTIMUTAGENIK Lemna minor TERHADAP ERITROSIT IKAN NILA (Oreochromis niloticus

    Directory of Open Access Journals (Sweden)

    Erma Musbita Tyastuti

    2016-09-01

    Full Text Available Limbah cair batik di Solo sebagian besar dibuang langsung ke perairan tanpa diolah terlebih dahulu dan menyebabkan pencemaran air. Kandungan logam berat di dalam limbah cair batik dapat memicu efek genotoksik seperti pembentukan mikronukleus. Lemna minor berpotensi sebagai antimutagen dan mencegah pembentukan mikronukleus karena mengandung senyawa aktif seperti karoten dan asam amino. Penelitian ini bertujuan untuk mengetahui ekogenotoksisitas limbah cair batik dan efek antimutagenik Lemna minor terhadap eritrosit ikan nila. Penelitian dilakukan di Laboratorium Biologi UMS dengan pemaparan limbah cair batik 0ppm/L, 2500 ppm/L, 5000 ppm/L dan 7500 ppm/L terhadap 2 kelompok ikan nila dengan diet pelet dan Lemna minor. Hasil penelitian menunjukkan bahwa paparan limbah cair batik memicu pembentukan mikronukleus dengan frekwensi tertinggi pada konsentrasi paparan 7500 ppm/L. Lemna minor juga terbukti memiliki potensi antimutagenik karena mampu menekan frekwensi mikronukleus lebih rendah dibandingkan diet pelet.

  9. Vertical transmission of microcystins to Nile crocodile (Crocodylus niloticus) eggs.

    Science.gov (United States)

    Singo, Alukhethi; Myburgh, Jan G; Laver, Peter N; Venter, Elizabeth A; Ferreira, Gezina C H; Rösemann, Gertruida M; Botha, Christo J

    2017-08-01

    Cyanobacteria or blue green algae are known for their extensive and highly visible blooms in eutrophic, stagnant freshwater bodies. Climate change and global warming have also contributed to a rise in toxic cyanobacterial blooms. One of the most important cyanobacteria is Microcystis aeruginosa, which can synthesize various microcystins that can affect the health of terrestrial and aquatic animals. Commercial Nile crocodile (Crocodylus niloticus) farming in South Africa is based on keeping breeders (adult males and females) in big dams on farms (captive-bred approach). Unfortunately, cyanobacterial blooms in the breeder dams are a concern to farm owners, managers and veterinarians. The main objectives of this research project were to determine if microcystins were present in the contents of crocodile eggs and the liver and yolk of dead hatchlings, and to determine if the reduced hatchability on commercial farms might be caused by these toxins. Furthermore, the concentration of microcystins in the breeder dam was monitored on a monthly basis spanning the ovulation and egg laying period. During the hatching season microcystin concentrations in unfertilised eggs, egg shell membranes and in the yolk and liver of dead hatchlings were determined using liquid chromatography-high resolution mass spectrometry (LC-HRMS). Microcystins were detected in Nile crocodile egg and hatchling samples. Microcystin (MC-LR, MC-RR, MC-YR) concentrations in the crocodile egg and hatchling samples collected from clutches with a good hatching rate (≥90%) ranged between 0 and 1.76 ng g -1 , with the highest concentration in the egg shell membranes. Microcystin concentrations in samples collected from clutches with a bad hatching rate (≤10%) ranged from 0 - 1.63 ng g -1 with the highest concentration detected in the hatchling yolk. However, the concentrations were probably underestimated as the percentage recovery from spiked samples was very low with the extraction method employed

  10. Stability of cyanotoxins, microcystin-LR, microcystin-RR and nodularin in seawater and BG-11 medium of different salinity

    OpenAIRE

    Hanna Mazur; Marcin Pliñski

    2001-01-01

    Microcystins and nodularin are potent hepatotoxins produced by fresh and seawater cyanobacteria. The persistence of three hepatotoxins - microcystin-LR, microcystin-RR and nodularin - was investigated in sterile BG-11 medium of different salinity and in water collected from the Gulf of Gdansk. After 21 days of incubation at 17 ± 1oC and constant illumination of about 40 µmol photon m-2 s-1 the concentration of toxins decreased by about 30-37%. No significant changes in toxin concent...

  11. Dynamics of microcystin-degrading bacteria in mucilage of Microcystis.

    Science.gov (United States)

    Maruyama, T; Kato, K; Yokoyama, A; Tanaka, T; Hiraishi, A; Park, H D

    2003-08-01

    To reveal the process of degradation of hepatotoxic microcystin produced in Microcystis cells during the Microcystis bloom period, we used fluorescence in situ hybridization (FISH) to analyze the population dynamics of microcystin-degrading bacteria in Microcystis mucilage. We designed and applied an oligonucleotide probe targeted to the 16S rRNA sequence of strain Y2 of a microcystin-degrading bacterium (MCD-bacterium), which was isolated from Lake Suwa, Japan. In both the 1998 and 1999 tests, FISH clearly showed that MCD-bacteria existed in the mucilage and that, when a high concentration of cell-bound microcystin was detected, MCD-bacteria exceeded 10% of the sum of bacteria hybridized with group-specific probes. The concentration of MCD-bacteria was highest in summer 1998, when a toxic species, M. viridis, was dominant. There was a high correlation between the number of MCD-bacteria in the mucilage and the concentration of cell-bound microcystin in the lake. Our results suggest that MCD-bacteria responded to changes in the concentration of microcystin and degraded the microcystin when it was released from Microcystis cells. We also analyzed changes in the bacterial community structure associated with the Microcystis colonies by using domain- and group-specific oligonucleotide probes. Changes in the concentrations of the Cytophaga/Flavobacterium group and delta-Proteobacteria, which can degrade macromolecules derived from Microcystis cells, were synchronized with changes in the concentration of Microcystis. The results not only suggest the significant role of MCD-bacteria in detoxification, but also demonstrate a possible sequence of degradation from Microcystis cells to microcystin maintained in the cell, which is then carried out by bacterial consortia in the mucilage.

  12. Biodegradation of microcystins during gravity-driven membrane (GDM ultrafiltration.

    Directory of Open Access Journals (Sweden)

    Esther Kohler

    Full Text Available Gravity-driven membrane (GDM ultrafiltration systems require little maintenance: they operate without electricity at ultra-low pressure in dead-end mode and without control of the biofilm formation. These systems are already in use for water purification in some regions of the world where adequate treatment and distribution of drinking water is not readily available. However, many water bodies worldwide exhibit harmful blooms of cyanobacteria that severely lower the water quality due to the production of toxic microcystins (MCs. We studied the performance of a GDM system during an artificial Microcystis aeruginosa bloom in lake water and its simulated collapse (i.e., the massive release of microcystins over a period of 21 days. Presence of live or destroyed cyanobacterial cells in the feed water decreased the permeate flux in the Microcystis treatments considerably. At the same time, the microbial biofilms on the filter membranes could successfully reduce the amount of microcystins in the filtrate below the critical threshold concentration of 1 µg L(-1 MC for human consumption in three out of four replicates after 15 days. We found pronounced differences in the composition of bacterial communities of the biofilms on the filter membranes. Bacterial genera that could be related to microcystin degradation substantially enriched in the biofilms amended with microcystin-containing cyanobacteria. In addition to bacteria previously characterized as microcystin degraders, members of other bacterial clades potentially involved in MC degradation could be identified.

  13. Stability of cyanotoxins, microcystin-LR, microcystin-RR and nodularin in seawater and BG-11 medium of different salinity

    Directory of Open Access Journals (Sweden)

    Hanna Mazur

    2001-09-01

    Full Text Available Microcystins and nodularin are potent hepatotoxins produced by fresh and seawater cyanobacteria. The persistence of three hepatotoxins - microcystin-LR, microcystin-RR and nodularin - was investigated in sterile BG-11 medium of different salinity and in water collected from the Gulf of Gdansk. After 21 days of incubation at 17 ± 1oC and constant illumination of about 40 µmol photon m-2 s-1 the concentration of toxins decreased by about 30-37%. No significant changes in toxin concentration in the BG-11 media of different salinity were observed. When toxins were incubated in non-sterile seawater, their concentrations decreased markedly. It is likely that some strains of bacteria are responsible for the breakdown of the toxins. Nodularin turned out to be more resistant to biodegradation than the two microcystins. The influence of certain components of cyanobacteria cells on the accelerated rate of toxin degradation was also considered.

  14. Microcystin mcyA and mcyE Gene Abundances Are Not Appropriate Indicators of Microcystin Concentrations in Lakes.

    Directory of Open Access Journals (Sweden)

    Lucas J Beversdorf

    Full Text Available Cyanobacterial harmful algal blooms (cyanoHABs are a primary source of water quality degradation in eutrophic lakes. The occurrence of cyanoHABs is ubiquitous and expected to increase with current climate and land use change scenarios. However, it is currently unknown what environmental parameters are important for indicating the presence of cyanoHAB toxins making them difficult to predict or even monitor on time-scales relevant to protecting public health. Using qPCR, we aimed to quantify genes within the microcystin operon (mcy to determine which cyanobacterial taxa, and what percentage of the total cyanobacterial community, were responsible for microcystin production in four eutrophic lakes. We targeted Microcystis-16S, mcyA, and Microcystis, Planktothrix, and Anabaena-specific mcyE genes. We also measured microcystins and several biological, chemical, and physical parameters--such as temperature, lake stability, nutrients, pigments and cyanobacterial community composition (CCC--to search for possible correlations to gene copy abundance and MC production. All four lakes contained Microcystis-mcyE genes and high percentages of toxic Microcystis, suggesting Microcystis was the dominant microcystin producer. However, all genes were highly variable temporally, and in few cases, correlated with increased temperature and nutrients as the summer progressed. Interestingly, toxin gene abundances (and biomass indicators were anti-correlated with microcystin in all lakes except the largest lake, Lake Mendota. Similarly, gene abundance and microcystins differentially correlated to CCC in all lakes. Thus, we conclude that the presence of microcystin genes are not a useful tool for eliciting an ecological role for toxins in the environment, nor are microcystin genes (e.g. DNA a good indicator of toxins in the environment.

  15. Prey composition in the carnivorous plants Utricularia inflata and U. gibba (Lentibulariaceae from Paria Peninsula, Venezuela

    Directory of Open Access Journals (Sweden)

    Elizabeth Gordon

    2007-12-01

    Full Text Available Las plantas carnívoras acuáticas del género Utricularia (Lentibulariaceae, capturan pequeños organismos acuáticos, como rotíferos, copépodos, y cladóceros, por medio de estructuras anatómicas semejantes a vesículas. Este estudio tuvo como objetivo determinar el tamaño y tipo de presas de U. gibba y U. inflata, recolectados en un pequeño lago y en un pastizal inundado, respectivamente, en la localidad de la Península de Paria (Estado Sucre, Venezuela. La acidez, conductividad, cantidad de oxígeno disuelto y la salinidad del agua se midieron in situ para cada sitio de muestreo; también se tomaron muestras de agua para determinar niveles de N-Kjeldahl, P-total, Na+, K+, Ca++, Mg++ y Cl-. Se midieron cincuenta vesículas de cada especie y se analizaron sus contenidos. Los valores de N-Kjeldahl y P-total fueron similares en ambos sitios, y semejantes a los conocidos para ecosistemas eutróficos; sin embargo, las concentraciones de Na+, K+, Ca++, Mg++ y los valores in situ de los parámetros del agua fueron más altos en el pastizal inundado. Las vesículas contenían los siguientes grupos de zooplancton: rotíferos, cladóceros, copépodos, anélidos, rizópodos, e insectos; y las siguientes divisiones de fitoplancton: Bacillariophyta, Chlorophyta, Cyanophyta y Euglenophyta. Las vesículas presentadas por U. inflata fueron menores en tamaño y en cantidad, pero mayores en abundancia y riqueza total de morfoespecies algales y animales en comparación con U. gibba. La similitud en cuanto a composición de presas a nivel taxonómico, entre las dos especies de plantas carnívoras, fue baja.

  16. The cyanobacterial endosymbiont of the unicellular algae Rhopalodia gibba shows reductive genome evolution

    Directory of Open Access Journals (Sweden)

    Lockhart Peter J

    2008-01-01

    Full Text Available Abstract Background Bacteria occur in facultative association and intracellular symbiosis with a diversity of eukaryotic hosts. Recently, we have helped to characterise an intracellular nitrogen fixing bacterium, the so-called spheroid body, located within the diatom Rhopalodia gibba. Spheroid bodies are of cyanobacterial origin and exhibit features that suggest physiological adaptation to their intracellular life style. To investigate the genome modifications that have accompanied the process of endosymbiosis, here we compare gene structure, content and organisation in spheroid body and cyanobacterial genomes. Results Comparison of the spheroid body's genome sequence with corresponding regions of near free-living relatives indicates that multiple modifications have occurred in the endosymbiont's genome. These include localised changes that have led to elimination of some genes. This gene loss has been accompanied either by deletion of the respective DNA region or replacement with non-coding DNA that is AT rich in composition. In addition, genome modifications have led to the fusion and truncation of genes. We also report that in the spheroid body's genome there is an accumulation of deleterious mutations in genes for cell wall biosynthesis and processes controlled by transposases. Interestingly, the formation of pseudogenes in the spheroid body has occurred in the presence of intact, and presumably functional, recA and recF genes. This is in contrast to the situation in most investigated obligate intracellular bacterium-eukaryote symbioses, where at least either recA or recF has been eliminated. Conclusion Our analyses suggest highly specific targeting/loss of individual genes during the process of genome reduction and establishment of a cyanobacterial endosymbiont inside a eukaryotic cell. Our findings confirm, at the genome level, earlier speculation on the obligate intracellular status of the spheroid body in Rhopalodia gibba. This

  17. A review of reproductive toxicity of microcystins

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Liang, E-mail: chan91@yeah.net [Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Jun, E-mail: chenjun@ihb.ac.cn [Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China); Zhang, Xuezhen, E-mail: xuezhen@mail.hzau.edu.cn [College of Fisheries, Huazhong Agricultural University, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070 (China); Xie, Ping, E-mail: xieping@ihb.ac.cn [Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China)

    2016-01-15

    Highlights: • Reproductive toxicity of MCs on mammals, fishes, amphibians, and birds is reviewed. • PP1/2A inhibition and oxidative stress are important toxic mechanisms of MCs. • Reproductive toxicity of MCs may be closely related to endocrine-disrupting effects. • The trans-generational toxicity of microcystins is a matter of concern. • Data concerning female reproductive and sex-specific effects of MCs are lacking. - Abstract: Animal studies provide strong evidence of positive associations between microcystins (MCs) exposure and reproductive toxicity, representing a threat to human reproductive health and the biodiversity of wild life. This paper reviews current knowledge of the reproductive toxicity of MCs, with regard to mammals, fishes, amphibians, and birds, mostly in males. Toxicity of MCs is primarily governed by the inhibition of protein phosphatases 1 and 2A (PP1 and PP2A) and disturbance of cellular phosphorylation balance. MCs exposure is related to excessive production of reactive oxygen species (ROS) and oxidative stress, leading to cytoskeleton disruption, mitochondria dysfunction, endoplasmic reticulum (ER) stress, and DNA damage. MCs induce cell apoptosis mediated by the mitochondrial and ROS and ER pathways. Through PP1/2A inhibition and oxidative stress, MCs lead to differential expression/activity of transcriptional factors and proteins involved in the pathways of cellular differentiation, proliferation, and tumor promotion. MC-induced DNA damage is also involved in carcinogenicity. Apart from a direct effect on testes and ovaries, MCs indirectly affect sex hormones by damaging the hypothalamic-pituitary-gonad (HPG) axis and liver. Parental exposure to MCs may result in hepatotoxicity and neurotoxicity of offspring. We also summarize the current research gaps which should be addressed by further studies.

  18. Interference by plastics additives in the HPLC determination of microcystin-LR and -YR.

    Science.gov (United States)

    Ikawa, M; Phillips, N; Haney, J F; Sasner, J J

    1999-06-01

    Plastics devices used for the field collection of water samples may contain plastics additives which will interfere with the HPLC determination of the cyanobacterial toxins microcystins. The presence of the additives resorcinol monobenzoate or 2,4-dihydroxybenzophenone can interfere with the determination of microcystin-LR. The presence of bisphenol A in plastics can interfere with the determination of microcystin-YR.

  19. Ingestion of microcystins by Daphnia: Intestinal uptake and toxic effects

    DEFF Research Database (Denmark)

    Rohrlack, T.; Christoffersen, K.; Dittmann, E.

    2005-01-01

    We investigated the intestinal uptake and adverse effects of microcystins ingested with Microcystis on Daphnia galeata. The gut structure, blood microcystin concentration, appearance, and movements of Daphnia fed Microcystis PCC 7806 or a microcystin-deficient PCC 7806 mutant were monitored over...

  20. EVALUACIÓN DE LA PLANTA Lemna minor COMO BIORREMEDIADORA DE AGUAS CONTAMINADAS CON MERCURIO

    Directory of Open Access Journals (Sweden)

    Adolfo D. Arenas

    2011-01-01

    Full Text Available Se evaluó la capacidad biorremediadora de Lemna minor en función del tiempo en aguas contaminadas con mercurio mediante un diseño experimental de 3 bloques al azar con cinco réplicas: un grupo experimental con 100 g de Lemna, 7,5 L de agua contaminada con Hg (0,13 mgL-1 y solución nutritiva; un grupo Testigo con 100 g de Lemna, 7,5 L de agua y solución nutritiva y un grupo control con mercurio al nivel de 0,13 mgL-1 en agua destilada sin plantas. La eficiencia de remoción de mercurio de la Lemna minor, en 22 días, fue de 30%. Las variables peso fresco, peso seco, y nitrógeno y fósforo foliares no presentaron diferencias significativas entre los dos tratamientos. La absorción de potasio, fue afectada por los niveles de mercurio. La planta Lemna minor representa una alternativa para la remoción de mercurio en aguas contaminadas hasta un nivel de 0,13 mg/L.

  1. Microcystin Prevalence throughout Lentic Waterbodies in Coastal Southern California

    Directory of Open Access Journals (Sweden)

    Meredith D. A. Howard

    2017-07-01

    Full Text Available Toxin producing cyanobacterial blooms have increased globally in recent decades in both frequency and intensity. Despite the recognition of this growing risk, the extent and magnitude of cyanobacterial blooms and cyanotoxin prevalence is poorly characterized in the heavily populated region of southern California. Recent assessments of lentic waterbodies (depressional wetlands, lakes, reservoirs and coastal lagoons determined the prevalence of microcystins and, in some cases, additional cyanotoxins. Microcystins were present in all waterbody types surveyed although toxin concentrations were generally low across most habitats, as only a small number of sites exceeded California’s recreational health thresholds for acute toxicity. Results from passive samplers (Solid Phase Adsorption Toxin Tracking (SPATT indicated microcystins were prevalent throughout lentic waterbodies and that traditional discrete samples underestimated the presence of microcystins. Multiple cyanotoxins were detected simultaneously in some systems, indicating multiple stressors, the risk of which is uncertain since health thresholds are based on exposures to single toxins. Anatoxin-a was detected for the first time from lakes in southern California. The persistence of detectable microcystins across years and seasons indicates a low-level, chronic risk through both direct and indirect exposure. The influence of toxic cyanobacterial blooms is a more complex stressor than presently recognized and should be included in water quality monitoring programs.

  2. Hydroxycinnamoylmalated flavone C-glycosides from Lemna japonica.

    Science.gov (United States)

    Bai, Huan-Huan; Wang, Ni-Ni; Mi, Jiao; Yang, Tao; Fang, Dong-Mei; Wu, Lin-Wei; Zhao, Hai; Li, Guo-You

    2018-01-01

    Three previously undescribed flavone C-glycosides (1-3), along with seven known ones (4-10), were isolated and characterized from the smallest flowering aquatic plant, Lemna japonica. On the basis of spectroscopic analysis and alkaline hydrolysis, compounds 1-3 were identified to be luteolin 6-C-(2″-O-trans-caffeoyl-d-malate)-β-glucoside (1), apigenin 6-C-(2″-O-trans-caffeoyl-d-malate)-β-glucoside (2), and luteolin 6-C-(2″-O-trans-coumaroyl-d-malate)-β-glucoside (3). Compounds 1-3 are characteristic of a trans-coumaroyl-d-malate or trans-caffeoyl-d-malate linked to C-2″ of the glucose, which was reported for the first time. Compounds 1-3 exhibited weak cytotoxicity against HepG-2, SW-620, and A-549 cell lines, with IC 50 values between 42.5 and 19.2μg/ml, and moderate antioxidant activity. Meanwhile compound 3 displayed moderate nematocidal activity with an EC 50 value of 1.56mg/ml. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Toxicological evaluation of bacterial decolourised anaerobically treated distillery effluent with common duckweed (Lemna minor).

    Science.gov (United States)

    Chandra, Ram; Srivastava, Archana

    2004-01-01

    Duckweed (Lemna minor) a small vascular plant, grows rapidly, is sensitive to a wide variety of toxicants and is easy to culture. A method is described that measures duckweed frond growth, chlorophyll, protein and biomass content as indicator of growth inhibition. The physico-chemical analysis of anaerobically treated distillery effluent revealed high BOD (28,000 mg/l), COD (52,400 mg/l) and dark brown colour (180,000 Co. Pt.). This effluent showed high toxicity to Lemna minor after 96 h of exposure in laboratory condition. EC50 of the fronds for chlorophyll, protein and biomass was found to be 25%, however, the bacterial decolourised effluent showed reduction of BOD (87.50%), COD (84.50%) and colour (76%). Further the toxicity evaluation with Lemna minor showed toxicity reduction up to 63% for all tested parameters. The EC50 noted for chlorophyll, protein and biomass was 100% concentration of decolourised effluent.

  4. Effects of cell-bound microcystins on survival and feeding of Daphnia spp

    DEFF Research Database (Denmark)

    Rohrlack, T; Dittmann, E; Börner, T

    2001-01-01

    microcystin synthesis, were compared. Additionally, the relationship between microcystin ingestion rate by the Daphnia clones and Daphnia survival time was analyzed. Microcystins ingested with Microcystis cells were poisonous to all Daphnia clones tested. The median survival time of the animals was closely...... correlated to their microcystin ingestion rate. It was therefore suggested that differences in survival among Daphnia clones were due to variations in microcystin intake rather than due to differences in susceptibility to the toxins. The correlation between median survival time and microcystin ingestion rate...... could be described by a reciprocal power function. Feeding experiments showed that, independent of the occurrence of microcystins, cells of wild-type PCC7806 and its mutant are able to inhibit the feeding activity of Daphnia. Both variants of PCC7806 were thus ingested at low rates. In summary, our...

  5. Hot and toxic: Temperature regulates microcystin release from cyanobacteria.

    Science.gov (United States)

    Walls, Jeremy T; Wyatt, Kevin H; Doll, Jason C; Rubenstein, Eric M; Rober, Allison R

    2018-01-01

    The mechanisms regulating toxin release by cyanobacteria are poorly understood despite the threat cyanotoxins pose to water quality and human health globally. To determine the potential for temperature to regulate microcystin release by toxin-producing cyanobacteria, we evaluated seasonal patterns of water temperature, cyanobacteria biomass, and extracellular microcystin concentration in a eutrophic freshwater lake dominated by Planktothrix agardhii. We replicated seasonal variation in water temperature in a concurrent laboratory incubation experiment designed to evaluate cause-effect relationships between temperature and toxin release. Lake temperature ranged from 3 to 27°C and cyanobacteria biomass increased with warming up to 18°C, but declined rapidly thereafter with further increases in temperature. Extracellular microcystin concentration was tightly coupled with temperature and was most elevated between 20 and 25°C, which was concurrent with the decline in cyanobacteria biomass. A similar trend was observed in laboratory incubations where productivity-specific microcystin release was most elevated between 20 and 25°C and then declined sharply at 30°C. We applied generalized linear mixed modeling to evaluate the strength of water temperature as a predictor of cyanobacteria abundance and microcystin release, and determined that warming≥20°C would result in a 36% increase in microcystin release when Chlorophyll a was ≤50μgl -1 . These results show a temperature threshold for toxin release in P. agardhii, which demonstrates a potential to use water temperature to forecast bloom severity in eutrophic lakes where blooms can persist year-round with varying degrees of toxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Caracterización molecular por patrones electroforéticos de isoenzimas esterasas en Lemna aequinoctialis y Lemna valdiviana (lemnaceae de Costa Rica (ING

    Directory of Open Access Journals (Sweden)

    Sharon Jiménez Delgado

    2016-03-01

    Full Text Available The Lemnaceae family lacks morphologic and anatomical characteristics with comparative aims and for that reason the molecular studies has been necessary a differentiation. In Costa Rica there are two species of Lemna: Lemna aequinoctialis and Lemna valdiviana. With the objective of a molecular characterization and differentiation of both species were extracted isoenzymes esterases. The study was carried out in the Molecular Genetics Laboratory of the School of Biological Sciences at Universidad Nacional, Heredia, Costa Rica. The technical electrophoresis in gel of polyacrylamida SDS-PAGE was used. It was difference in the pattern of isoenzymes between both species. According to previous molecular studies based on morphology and anatomy, flavonoides, isoenzymes, and DNA sequences of certain genes both species are very different; in addition they belong to different monophyletics groups. On the other hand, the importance of this molecular characterization is its possible use in water treatment, because the esterases have had important in the bioremediation. Also, species of the Lemnaceae family are used in the water treatment like bioremediation.

  7. GROWTH RESPONSE OF THE DUCKWEED LEMNA MINOR TO HEAVY METAL POLLUTION

    Directory of Open Access Journals (Sweden)

    N. Khellaf ، M. Zerdaoui

    2009-07-01

    Full Text Available To assess the tolerance and effect of heavy metals pollution on the duckweed Lemna minor, the aquatic plants were exposed to different concentrations of copper (Cu, nickel (Ni, cadmium (Cd and zinc (Zn in a quarter Coïc and Lessaint solution at pH = 6.1 (± 0.1 and under a daily regime of 16 h light (101 μmol/m2.s1. Copper at 0.2 mg/L and nickel at 0.5 mg/L promoted the growth of Lemna fronds. At higher concentrations, Cu and Ni inhibited the growth of duckweed; the EC50 (concentration causing 50% inhibition were 0.47 mg/L for Cu and 1.29 mg/L for Ni. Cadmium and zinc decreased by 50% the growth of fronds when the medium contained respectively 0.64 and 5.64 mg/L (EC50. Duckweed tolerated Cu, Ni, Cd and Zn at concentrations of 0.4, 3.0, 0.4 and 15.0 mg/L respectively without showing any visible signs of toxicity (chlorosis, frond disconnection and necrosis. On the basis of visible symptoms and the EC50 values, the toxicity of the metals on Lemna. minor was in decreasing order of damage: Cu > Cd > Ni > Zn. It was concluded that the duckweed Lemna. minor is very sensitive to copper and cadmium pollution.

  8. Effects of light and phytochrome in heterotrophic growth of Lemna minor L.

    NARCIS (Netherlands)

    Rombach, J.

    1976-01-01

    Axenic cultures of Lemna minor L. were grown on a medium containing sugars and amino acids. In continuous darkness the growth rate was one-tenth of the maximum in continuous light. In darkness early death revealed a thiamine deficiency; this

  9. Trophic transfer of cadmium from duckweed (Lemna Minor L.) to Tilapia (Oreochromis mossambicus)

    NARCIS (Netherlands)

    Xue, Yan; Peijnenburg, Willie J G M; Huang, Jin; Wang, Dengjun; Jin, Yan

    2018-01-01

    The transfer of the toxic heavy metal Cd from duckweed (Lemna minor L.) to the freshwater fish tilapia (Oreochromis mossambicus) was investigated. Concentrations of Cd in different chemical forms in duckweed and in different tissues (gut, edible muscle, and remnants) of tilapia, i.e.,

  10. Removal of microcystins by phototrophic biofilms – a microcosm study

    Czech Academy of Sciences Publication Activity Database

    Babica, Pavel; Bláha, Luděk; Maršálek, Blahoslav

    2005-01-01

    Roč. 12, č. 6 (2005), s. 369-374 ISSN 0944-1344 R&D Projects: GA ČR(CZ) GA206/03/1215 Institutional research plan: CEZ:AV0Z60050516 Keywords : microcystin * biofilm * biodegradation Subject RIV: EF - Botanics Impact factor: 1.518, year: 2005

  11. 2 Microcystin-RR Like Toxin.cdr

    African Journals Online (AJOL)

    Administrator

    Anabaena flos-aquae strain. CCAP 1403/13B cells were harvested at the late exponential phase by centrifugation and cell material lyophilized by freeze drying and .... Organization provisional guideline value of. 1 µg/l microcystin-LR (WHO, 1998). Conclusion. The presence of Anabaena flos-aquae especially in reservoirs ...

  12. Microcystin in cyanobacterial blooms in a Chilean lake.

    Science.gov (United States)

    Campos, V; Cantarero, S; Urrutia, H; Heinze, R; Wirsing, B; Neumann, U; Weckesser, J

    1999-05-01

    Cyanobacterial blooms dominated by Microcystis sp. occurred in lake Rocuant ("marisma", near Concepción/Chile) in February 1995 and 1996. In the bloom samples collected in both years the hepatotoxin microcystin was detected by RP-HPLC in both samples and in the sample of 1995 also by a toxicity assay using primary rat hepatocytes. In the bloom of 1995, the microcystin content of the dry bloom biomass was determined to be 130 micrograms/g on the basis of the RP-HPLC peak area and 800 micrograms/g on the basis of the rat hepatotoxicity assay, respectively. In the bloom of 1996, RP-HPLC analysis revealed a microcystin content of 8.13 micrograms/g bloom material dry weight. In this year no hepatotoxicity was measured using a concentration range up to 0.8 mg (d. w.) of bloom material per ml in the rat hepatotoxicity assay. This is the first report on the detection of microcystins in Chilean water bodies.

  13. Antioxidant Effect of Curcumin Against Microcystin- LR-Induced ...

    African Journals Online (AJOL)

    Purpose: To investigate the effect of curcumin on microcystin-LR (MC-LR)- induced renal oxidative damage in Balb/c mice. Methods: 40 male Balb/c mice were assigned randomly to 4 groups each having 10 mice. One group served as normal (saline treated) while another group was used as curcumin control. The third ...

  14. Quantification of microcystin-producing microcystis in freshwater ...

    African Journals Online (AJOL)

    Total Microcystis spp (microcystinproducing and non-producing strains) were quantified in the three selected study areas with the determination of the copy numbers of the phycocyanin (PC) operon. Microcystin-producing gene copy numbers were quantified using specific primer pair, amplifying the mcyB gene. Microcystis ...

  15. Removal mechanisms of benzotriazoles in duckweed Lemna minor wastewater treatment systems.

    Science.gov (United States)

    Gatidou, Georgia; Oursouzidou, Maria; Stefanatou, Aimilia; Stasinakis, Athanasios S

    2017-10-15

    The fate of five benzotriazoles (1H-benzotriazole, BTR; 4-methyl-1H-benzotriazole, 4TTR; 5-methyl-1H-benzotriazole, 5TTR; xylytriazole, XTR and 5-chlorobenzotriazole, CBTR) was studied in batch and continuous-flow Lemna minor systems and the role of different mechanisms on their removal was evaluated. Single and joint toxicity experiments were initially conducted using the Organization for Economic Co-operation and Development (OECD) protocol 221 and no inhibition on specific growth rate of Lemna minor was observed for concentrations up to 200μgL -1 . All tested substances were significantly removed in batch experiments with Lemna minor. Excepting 4TTR, full elimination of CBTR, XTR, 5TTR and BTR was observed up to the end of these experiments (36d), while the half-life values ranged between 1.6±0.3d (CBTR) and 25±3.6d (4-TTR). Calculation of kinetic constants for hydrolysis, photodegradation, and plant uptake revealed that for all BTRs the kinetic constants of plant uptake were by far higher comparing to those of the other mechanisms, reaching 0.394±0.161d -1 for CBTR. The operation of a continuous-flow Lemna minor system consisted of three mini ponds and a total hydraulic residence time of 8.3d showed sufficient removal for most target substances, ranging between 26% (4TTR) and 72% (CBTR). Application of a model for describing micropollutants removal in the examined system showed that plant uptake was the major mechanism governing BTRs removal in Lemna minor systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. A spontaneous mutant of microcystin biosynthesis: genetic characterization and effect on Daphnia

    DEFF Research Database (Denmark)

    Kabernick, M.; Rohrlack, T.; Christoffersen, K.

    2001-01-01

    Microcystis aeruginosa strain MRC is unique in its' possession of the mcyA-J gene cluster, which encodes microcystin synthetase, but its' inability to produce microcystins. M. aeruginosa strain MRD is genetically identical to MRC at numerous genomic loci examined, but produces a variety...... of microcystins, mainly with the amino acid tyrosine in the molecule. Zooplankton studies with Daphnia galeata and D. pulicaria, using the mutant (MRC) and its' wild type (MRD), showed for the first time that microcystins other than microcystin-LR can be responsible for the poisoning of Daphnia by Microcystis....... Regardless of microcystin content, both Daphnia exhibited significantly reduced ingestion rates when fed with either strain of M. aeruginosa compared with the green alga Scenedesmus acutus. A disruption of the molting process in both Daphnia spp. was noted when these species were fed with MRC cells...

  17. Rhizobium paknamense sp. nov., isolated from lesser duckweeds (Lemna aequinoctialis).

    Science.gov (United States)

    Kittiwongwattana, Chokchai; Thawai, Chitti

    2013-10-01

    A Gram-stain-negative, rod-shaped bacterium was isolated and designated strain L6-8(T) during a study of endophytic bacterial communities in lesser duckweed (Lemna aequinoctialis). Cells of strain L6-8(T) were motile with peritrichous flagella. The analysis of the nearly complete 16S rRNA gene sequence indicated that strain L6-8(T) was phylogenetically related to species of the genus Rhizobium. Its closest relatives were Rhizobium borbori DN316(T) (97.6 %), Rhizobium oryzae Alt 505(T) (97.3 %) and Rhizobium pseudoryzae J3-A127(T) (97.0 %). The sequence similarity analysis of housekeeping genes recA, glnII, atpD and gyrB showed low levels of sequence similarity (Rhizobium with validly published names. The pH range for growth was 4.0-9.0 (optimum 6.0-7.0), and the temperature range for growth was 20-45 °C (optimum 30 °C). Strain L6-8(T) tolerated NaCl up to 2 % (w/v) (optimum 1 % NaCl). The predominant components of cellular fatty acids were C19 : 0 cyclo ω8c (31.32 %), summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c; 25.39 %) and C16 : 0 (12.03 %). The DNA G+C content of strain L6-8(T) was 60.4 mol% (Tm). nodC and nifH were not amplified in strain L6-8(T). DNA-DNA relatedness between strain L6-8(T) and R. borbori DN316(T), R. oryzae Alt505(T) and R. pseudoryzae J3-A127(T) was between 11.2 and 18.3 %. Based on the sequence similarity analyses, phenotypic, biochemical and physiological characteristics and DNA-DNA hybridization, strain L6-8(T) could be readily distinguished from its closest relatives and represents a novel species of the genus Rhizobium, for which the name Rhizobium paknamense sp. nov. is proposed. The type strain is L6-8(T) ( = NBRC 109338(T) = BCC 55142(T)).

  18. Effects of CuO nanoparticles on Lemna minor.

    Science.gov (United States)

    Song, Guanling; Hou, Wenhua; Gao, Yuan; Wang, Yan; Lin, Lin; Zhang, Zhiwei; Niu, Qiang; Ma, Rulin; Mu, Lati; Wang, Haixia

    2016-12-01

    Copper dioxide nanoparticles (NPs), which is a kind of important and widely used metal oxide NP, eventually reaches a water body through wastewater and urban runoff. Ecotoxicological studies of this kind of NPs effects on hydrophyte are very limited at present. Lemna minor was exposed to media with different concentrations of CuO NPs, bulk CuO, and two times concentration of Cu 2+ released from CuO NPs in culture media. The changes in plant growth, chlorophyll content, antioxidant defense enzyme activities [i.e., peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) activities], and malondialdehyde (MDA) content were measured in the present study. The particle size of CuO NPs and the zeta potential of CuO NPs and bulk CuO in the culture media were also analyzed to complementally evaluate their toxicity on duckweed. Results showed that CuO NPs inhibited the plant growth at lower concentration than bulk CuO. L. minor roots were easily broken in CuO NPs media under the experimental condition, and the inhibition occurred only partly because CuO NPs released Cu 2+ in the culture media. The POD, SOD, and CAT activities of L. minor increased when the plants were exposed to CuO NPs, bulk CuO NPs and two times the concentration of Cu 2+ released from CuO NPs in culture media, but the increase of these enzymes were the highest in CuO NPs media among the three kinds of materials. The MDA content was significantly increased compared with that of the control from 50 mg L -1 CuO NP concentration in culture media. CuO NPs has more toxicity on L. minor compared with that of bulk CuO, and the inhibition occurred only partly because released Cu 2+ in the culture media. The plant accumulated more reactive oxygen species in the CuO NP media than in the same concentration of bulk CuO. The plant cell encountered serious damage when the CuO NP concentration reached 50 mg L -1 in culture media. The toxicology of CuO NP on hydrophytes must be considered because that hydrophytes

  19. [ADMAdda5]-microcystins in Planktothrix agardhii strain PH-123 (cyanobacteria) -  importance for monitoring of microcystins in the environment

    DEFF Research Database (Denmark)

    Laub, J.; Henriksen, P.; Brittain, S.M.

    2002-01-01

    -reactivity with antibodies of an enzyme-linked immunosorbent assay (ELISA), emphasizing the potential underestimation of the toxicity of natural blooms dominated by Planktothrix when microcystin content is quantified using only an ELISA. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 351-357, 2002; Published online...

  20. Discovery of rare and highly toxic microcystins from lichen-associated cyanobacterium Nostoc sp. strain IO-102-I.

    Science.gov (United States)

    Oksanen, Ilona; Jokela, Jouni; Fewer, David P; Wahlsten, Matti; Rikkinen, Jouko; Sivonen, Kaarina

    2004-10-01

    The production of hepatotoxic cyclic heptapeptides, microcystins, is almost exclusively reported from planktonic cyanobacteria. Here we show that a terrestrial cyanobacterium Nostoc sp. strain IO-102-I isolated from a lichen association produces six different microcystins. Microcystins were identified with liquid chromatography-UV mass spectrometry by their retention times, UV spectra, mass fragmentation, and comparison to microcystins from the aquatic Nostoc sp. strain 152. The dominant microcystin produced by Nostoc sp. strain IO-102-I was the highly toxic [ADMAdda(5)]microcystin-LR, which accounted for ca. 80% of the total microcystins. We assigned a structure of [DMAdda(5)]microcystin-LR and [d-Asp(3),ADMAdda(5)]microcystin-LR and a partial structure of three new [ADMAdda(5)]-XR type of microcystin variants. Interestingly, Nostoc spp. strains IO-102-I and 152 synthesized only the rare ADMAdda and DMAdda subfamilies of microcystin variants. Phylogenetic analyses demonstrated congruence between genes involved directly in microcystin biosynthesis and the 16S rRNA and rpoC1 genes of Nostoc sp. strain IO-102-I. Nostoc sp. strain 152 and the Nostoc sp. strain IO-102-I are distantly related, revealing a sporadic distribution of toxin production in the genus Nostoc. Nostoc sp. strain IO-102-I is closely related to Nostoc punctiforme PCC 73102 and other symbiotic Nostoc strains and most likely belongs to this species. Together, this suggests that other terrestrial and aquatic strains of the genus Nostoc may have retained the genes necessary for microcystin biosynthesis.

  1. Laboratory studies of dissolved radiolabelled microcystin-LR in lake water

    DEFF Research Database (Denmark)

    Hyenstrand, Per; Rohrlack, Thomas; Beattie, Kenneth A

    2003-01-01

    The fate of dissolved microcystin-LR was studied in laboratory experiments using surface water taken from a eutrophic lake. Based on initial range finding, a concentration of 50 microg l(-1) dissolved 14C-microcystin-LR was selected for subsequent time-course experiments. The first was performed ...... fractions. The study demonstrated that biodegradation of dissolved microcystin-LR occurred in water collected at a lake surface with carbon dioxide as a major end-product....

  2. The Fate of Microcystins in the Environment and Challenges for Monitoring

    Directory of Open Access Journals (Sweden)

    Justine R. Schmidt

    2014-12-01

    Full Text Available Microcystins are secondary metabolites produced by cyanobacteria that act as hepatotoxins in higher organisms. These toxins can be altered through abiotic processes, such as photodegradation and adsorption, as well as through biological processes via metabolism and bacterial degradation. Some species of bacteria can degrade microcystins, and many other organisms metabolize microcystins into a series of conjugated products. There are toxicokinetic models used to examine microcystin uptake and elimination, which can be difficult to compare due to differences in compartmentalization and speciation. Metabolites of microcystins are formed as a detoxification mechanism, and little is known about how quickly these metabolites are formed. In summary, microcystins can undergo abiotic and biotic processes that alter the toxicity and structure of the microcystin molecule. The environmental impact and toxicity of these alterations and the metabolism of microcystins remains uncertain, making it difficult to establish guidelines for human health. Here, we present the current state of knowledge regarding the alterations microcystins can undergo in the environment.

  3. Identification of microcystins from three collection strains of Microcystis aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Campo, Francisca F. del [Departamento de Biologia, Universidad Autonoma de Madrid, Cantoblanco, 28049-Madrid (Spain); Ouahid, Youness, E-mail: ouahidyouness@gmail.co [Departamento de Biologia, Universidad Autonoma de Madrid, Cantoblanco, 28049-Madrid (Spain)

    2010-09-15

    Microcystins (MCs) are toxic cyclic heptapeptides produced by various cyanobacteria genera, especially Microcystis. We identified 10 out of 12 MCs produced by three Microcystis aeruginosa strains from cyanobacteria collections, UTEX 2666, UTEX 2670 and UAM 1303, by using two analytical methods: Matrix-assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF/MS) and HPLC Photodiode Array Detector coupled to a hybrid Quadrupole Time of Flight Mass Spectrometry (HPLC-PDA-QTOF/MS). MALDI-TOF/MS failed to detect non-polar MCs, such as MC-LY and MC-LW. HPLC-QTOF/MS permitted the accurate identification of most MCs present in methanolic extracts. Besides, three new MCs, namely: [D-Glu(OCH{sub 3}){sup 6}, D-Asp{sup 3}] MC-LAba, MC-YL and MC-YM were detected by HPLC-QTOF/MS. - Three new microcystin variants identified by HPLC-QTOF/MS.

  4. Investigations into the biodegradation of microcystin-LR in wastewaters

    International Nuclear Information System (INIS)

    Ho, Lionel; Hoefel, Daniel; Palazot, Sebastien; Sawade, Emma; Newcombe, Gayle; Saint, Christopher P.; Brookes, Justin D.

    2010-01-01

    Microcystins are potent hepatotoxins that can be produced by cyanobacteria. These organisms can proliferate in wastewaters due to a number of factors including high concentrations of nutrients for growth. As treated wastewaters are now being considered as supplementary drinking water sources, in addition to their frequent use for irrigated agriculture, it is imperative that these wastewaters are free of toxins such as microcystins. This study investigated the potential for biodegradation of microcystin-LR (MCLR) in wastewaters through a biological sand filtration experiment and in static batch reactor experiments. MCLR was effectively removed at a range of concentrations and at various temperatures, with degradation attributed to the action of microorganisms indigenous to the wastewaters. No hepatotoxic by-products were detected following the degradation of MCLR as determined by a protein phosphatase inhibition assay. Using TaqMan polymerase chain reaction, the first gene involved in bacterial degradation of MCLR (mlrA) was detected and the responsible bacteria shown to increase with the amount of MCLR being degraded. This finding suggested that the degradation of MCLR was dependent upon the abundance of MCLR-degrading organisms present within the wastewater, and that MCLR may provide bacteria with a significant carbon source for proliferation; in turn increasing MCLR removal.

  5. Pseudodiarrhoea in zebra mussels Dreissena polymorpha (Pallas) exposed to microcystins.

    Science.gov (United States)

    Juhel, Guillaume; Davenport, John; O'Halloran, John; Culloty, Sarah; Ramsay, Ruth; James, Kevin; Furey, Ambrose; Allis, Orla

    2006-03-01

    Microcystins are produced by bloom-forming cyanobacteria and pose significant health and ecological problems. In this study we show that zebra mussels respond differently to different strains of Microcystis aeruginosa, and that a highly toxic strain causes zebra mussels to produce large quantities of mucous pseudofaeces, 'pseudodiarrhoea', that are periodically expelled hydraulically through the pedal gape by shell valve adductions rather than by the normal ciliary tracts. Analysis of the pseudofaecal ejecta showed that the proportion of Microcystis aeruginosa relative to Asterionella formosa was high in the pseudofaeces and even higher in the 'pseudodiarrhoea' when a mixed diet was given to the mussels. This confirms that very toxic Microcystis aeruginosa were preferentially being rejected by comparison with the non-toxic diatom in the pseudofaeces and even more so in the 'pseudodiarrhoea'. Such selective rejection was not observed with low or non-toxic strains and would therefore tend to enhance the presence of toxic Microcystis aeruginosa in mixed Microcystis aeruginosa cyanobacterial blooms, as well as transferring toxins from the water column to the benthos. The observed acute irritant response to the toxin represents the first demonstration of an adverse sublethal effect of microcystins on invertebrate ecophysiology. Our results also suggest that it could be a specific response to microcystin-LF, a little studied toxin variant.

  6. Structural Characterization of New Microcystins Containing Tryptophan and Oxidized Tryptophan Residues

    Science.gov (United States)

    Puddick, Jonathan; Prinsep, Michèle R.; Wood, Susanna A.; Miles, Christopher O.; Rise, Frode; Cary, Stephen Craig; Hamilton, David P.; Wilkins, Alistair L.

    2013-01-01

    Microcystins are cyclic peptides produced by cyanobacteria, which can be harmful to humans and animals when ingested. Eight of the (more than) 90 microcystin variants presently characterized, contain the amino acid tryptophan. The well-researched oxidation products of tryptophan; kynurenine, oxindolylalanine, and N-formylkynurenine, have been previously identified in intact polypeptides but microcystin congeners containing oxidized tryptophan moieties have not been reported. Liquid chromatography-tandem mass spectrometric analysis of an extract of Microcystis CAWBG11 led to the tentative identification of two new tryptophan-containing microcystins (MC‑WAba and MC-WL), as well as eight other microcystin analogs containing kynurenine, oxindolylalanine and N‑formylkynurenine (Nfk). Investigation of one of these congeners (MC‑NfkA) by nuclear magnetic resonance spectroscopy was used to verify the presence of Nfk in the microcystin. Liquid chromatography-mass spectrometry analysis of a tryptophan oxidation experiment demonstrated that tryptophan-containing microcystins could be converted into oxidized tryptophan analogs and that low levels of oxidized tryptophan congeners were present intracellularly in CAWBG11. MC-NfkR and MC-LNfk were detected in standards of MC-WR and MC-LW, indicating that care during storage of tryptophan-containing microcystins is required. PMID:23966035

  7. Distribution of microcystins in a lake foodweb: no evidence for biomagnification

    NARCIS (Netherlands)

    Ibelings, B.W.; Bruning, K.; De Jonge, J.; Wolfstein, K.; Pires, L.M.D.; Postma, J.; Burger, T.

    2005-01-01

    Microcystins, toxins produced by cyanobacteria, may play a role in fish kills, although their specific contribution remains unclear. A better understanding of the eco-toxicological effects of microcystins is hampered by a lack of analyses at different trophic levels in lake foodwebs. We present 3

  8. The enzymatic and antioxidative stress response of Lemna minor to copper and a chloroacetamide herbicide.

    Science.gov (United States)

    Obermeier, Michael; Schröder, Christian A; Helmreich, Brigitte; Schröder, Peter

    2015-12-01

    Lemna minor L., a widely used model plant for toxicity tests has raised interest for its application to phytoremediation due to its rapid growth and ubiquitous occurrence. In rural areas, the pollution of water bodies with heavy metals and agrochemicals poses a problem to surface water quality. Among problematic compounds, heavy metals (copper) and pesticides are frequently found in water bodies. To establish duckweed as a potential plant for phytoremediation, enzymatic and antioxidative stress responses of Lemna minor during exposure to copper and a chloroacetamide herbicide were investigated in laboratory studies. The present study aimed at evaluating growth and the antioxidative and glutathione-dependent enzyme activity of Lemna plants and its performance in a scenario for phytoremediation of copper and a chloroacetamide herbicide. Lemna minor was grown in Steinberg medium under controlled conditions. Plants were treated with CuSO4 (ion conc. 50 and 100 μg/L) and pethoxamide (1.25 and 2.5 μg/L). Measurements following published methods focused on plant growth, oxidative stress, and basic detoxification enzymes. Duckweed proved to survive treatment with the respective concentrations of both pollutants very well. Its growth was inhibited scarcely, and no visible symptoms occurred. On the cellular basis, accumulation of O2(-) and H2O2 were detected, as well as stress reactions of antioxidative enzymes. Duckweed detoxification potential for organic pollutants was high and increased significantly with incubation. Pethoxamide was found to be conjugated with glutathione. Copper was accumulated in the fronds at high levels, and transient oxidative defense reactions were triggered. This work confirms the significance of L. minor for the removal of copper from water and the conjugation of the selective herbicide pethoxamide. Both organic and inorganic xenobiotics induced different trends of enzymatic and antioxidative stress response. The strong increase of stress

  9. Evidence for a novel marine harmful algal bloom: Cyanotoxin (Microcystin) transfer from land to sea otters

    Science.gov (United States)

    Miller, Melissa A.; Kudela, Raphael M.; Mekebri, Abdu; Crane, Dave; Oates, Stori C.; Tinker, M. Timothy; Staedler, Michelle; Miller, Woutrina A.; Toy-Choutka, Sharon; Dominik, Clare; Hardin, Dane; Langlois, Gregg; Murray, Michael; Ward, Kim; Jessup, David A.

    2010-01-01

    "Super-blooms" of cyanobacteria that produce potent and environmentally persistent biotoxins (microcystins) are an emerging global health issue in freshwater habitats. Monitoring of the marine environment for secondary impacts has been minimal, although microcystin-contaminated freshwater is known to be entering marine ecosystems. Here we confirm deaths of marine mammals from microcystin intoxication and provide evidence implicating land-sea flow with trophic transfer through marine invertebrates as the most likely route of exposure. This hypothesis was evaluated through environmental detection of potential freshwater and marine microcystin sources, sea otter necropsy with biochemical analysis of tissues and evaluation of bioaccumulation of freshwater microcystins by marine invertebrates. Ocean discharge of freshwater microcystins was confirmed for three nutrient-impaired rivers flowing into the Monterey Bay National Marine Sanctuary, and microcystin concentrations up to 2,900 ppm (2.9 million ppb) were detected in a freshwater lake and downstream tributaries to within 1 km of the ocean. Deaths of 21 southern sea otters, a federally listed threatened species, were linked to microcystin intoxication. Finally, farmed and free-living marine clams, mussels and oysters of species that are often consumed by sea otters and humans exhibited significant biomagnification (to 107 times ambient water levels) and slow depuration of freshwater cyanotoxins, suggesting a potentially serious environmental and public health threat that extends from the lowest trophic levels of nutrient-impaired freshwater habitat to apex marine predators. Microcystin-poisoned sea otters were commonly recovered near river mouths and harbors and contaminated marine bivalves were implicated as the most likely source of this potent hepatotoxin for wild otters. This is the first report of deaths of marine mammals due to cyanotoxins and confirms the existence of a novel class of marine "harmful algal

  10. Detection of freshwater cyanotoxins and measurement of masked microcystins in tilapia from Southeast Asian aquaculture farms.

    Science.gov (United States)

    Greer, Brett; Maul, Ronald; Campbell, Katrina; Elliott, Christopher T

    2017-06-01

    Recently, there has been a rise in freshwater harmful algal blooms (HABs) globally, as well as increasing aquaculture practices. HABs can produce cyanotoxins, many of which are hepatotoxins. An ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for nine cyanotoxins across three classes including six microcystins, nodularin, cylindrospermopsin and anatoxin-a. The method was used to analyse free cyanotoxin(s) in muscle (n = 34), liver (n = 17) and egg (n = 9) tissue samples of 34 fish sourced from aquaculture farms in Southeast Asia. Conjugated microcystin was analysed by Lemieux oxidation to ascertain the total amount of microcystin present in muscle. Some tilapia accumulated free microcystin-LR in the muscle tissue at a mean of 15.45 μg/kg dry weight (dw), with total microcystin levels detected at a mean level of 110.1 μg/kg dw, indicating that the amount of conjugated or masked microcystin present in the fish muscle accounted for 85% of the total. Higher levels of cyanotoxin were detected in the livers, with approximately 60% of those tested being positive for microcystin-LR and microcystin-LF, along with cylindrospermopsin. Two fish from one of the aquaculture farms contained cylindrospermopsin in the eggs; the first time this has been reported. The estimated daily intake for free and total microcystins in fish muscle tissue was 2 and 14 times higher, respectively, than the tolerable daily intake value. This survey presents the requirement for further monitoring of cyanotoxins, including masked microcystins, in aquaculture farming in these regions and beyond, along with the implementation of guidelines to safeguard human health. Graphical abstract ᅟ.

  11. Evidence for a novel marine harmful algal bloom: cyanotoxin (microcystin transfer from land to sea otters.

    Directory of Open Access Journals (Sweden)

    Melissa A Miller

    Full Text Available "Super-blooms" of cyanobacteria that produce potent and environmentally persistent biotoxins (microcystins are an emerging global health issue in freshwater habitats. Monitoring of the marine environment for secondary impacts has been minimal, although microcystin-contaminated freshwater is known to be entering marine ecosystems. Here we confirm deaths of marine mammals from microcystin intoxication and provide evidence implicating land-sea flow with trophic transfer through marine invertebrates as the most likely route of exposure. This hypothesis was evaluated through environmental detection of potential freshwater and marine microcystin sources, sea otter necropsy with biochemical analysis of tissues and evaluation of bioaccumulation of freshwater microcystins by marine invertebrates. Ocean discharge of freshwater microcystins was confirmed for three nutrient-impaired rivers flowing into the Monterey Bay National Marine Sanctuary, and microcystin concentrations up to 2,900 ppm (2.9 million ppb were detected in a freshwater lake and downstream tributaries to within 1 km of the ocean. Deaths of 21 southern sea otters, a federally listed threatened species, were linked to microcystin intoxication. Finally, farmed and free-living marine clams, mussels and oysters of species that are often consumed by sea otters and humans exhibited significant biomagnification (to 107 times ambient water levels and slow depuration of freshwater cyanotoxins, suggesting a potentially serious environmental and public health threat that extends from the lowest trophic levels of nutrient-impaired freshwater habitat to apex marine predators. Microcystin-poisoned sea otters were commonly recovered near river mouths and harbors and contaminated marine bivalves were implicated as the most likely source of this potent hepatotoxin for wild otters. This is the first report of deaths of marine mammals due to cyanotoxins and confirms the existence of a novel class of marine

  12. Non-microcystin producing Microcystis wesenbergii (Komarek) Komarek (Cyanobacteria) representing a main waterbloom-forming species in Chinese waters

    Energy Technology Data Exchange (ETDEWEB)

    Xu Yao [Institute of Hydrobiology, Chinese Academy of Sciences, Donghu Nanlu 7, Wuhan, Hubei 430072 (China); College of Geographical Science, Nanjing Normal University, Nanjing 210097 (China); Wu Zhongxing [Institute of Hydrobiology, Chinese Academy of Sciences, Donghu Nanlu 7, Wuhan, Hubei 430072 (China); Yu Boshi [Institute of Hydrobiology, Chinese Academy of Sciences, Donghu Nanlu 7, Wuhan, Hubei 430072 (China); School of Nature Resources, Southwest Forestry University, Kunming 650224 (China); Peng Xin; Yu Gongliang [Institute of Hydrobiology, Chinese Academy of Sciences, Donghu Nanlu 7, Wuhan, Hubei 430072 (China); Wei Zhihong [Research Center of the Erhai Lake, Dali, Yunnan 671000 (China); Wang Guoxiang [College of Geographical Science, Nanjing Normal University, Nanjing 210097 (China); Li Renhui [Institute of Hydrobiology, Chinese Academy of Sciences, Donghu Nanlu 7, Wuhan, Hubei 430072 (China)], E-mail: reli@ihb.ac.cn

    2008-11-15

    It is well known that several morphospecies of Microcystis, such as Microcystis aeruginosa (Kuetzing) Lemmermann and Microcystis viridis (A. Brown) Lemmermann can produce hepatotoxic microcystins. However, previous studies gave contradictory conclusions about microcystin production of Microcystis wesenbergii (Komarek) Komarek. In the present study, ten Microcystis morphospecies were identified in waterblooms of seven Chinese waterbodies, and Microcystis wesenbergii was shown as the dominant species in these waters. More than 250 single colonies of M. wesenbergii were chosen, under morphological identification, to examine whether M. wesenbergii produce hepatotoxic microcystin by using multiplex PCR for molecular detection of a region (mcyA) of microcystin synthesis genes, and chemical analyses of microcystin content by ELISA and HPLC for 21 isolated strains of M. wesenbergii from these waters were also performed. Both molecular and chemical methods demonstrated that M. wesenbergii from Chinese waters did not produce microcystin. - Both molecular and chemical methods demonstrated that Microcystis wesenbergii was not a microcystin producer in Chinese waters.

  13. Non-microcystin producing Microcystis wesenbergii (Komarek) Komarek (Cyanobacteria) representing a main waterbloom-forming species in Chinese waters

    International Nuclear Information System (INIS)

    Xu Yao; Wu Zhongxing; Yu Boshi; Peng Xin; Yu Gongliang; Wei Zhihong; Wang Guoxiang; Li Renhui

    2008-01-01

    It is well known that several morphospecies of Microcystis, such as Microcystis aeruginosa (Kuetzing) Lemmermann and Microcystis viridis (A. Brown) Lemmermann can produce hepatotoxic microcystins. However, previous studies gave contradictory conclusions about microcystin production of Microcystis wesenbergii (Komarek) Komarek. In the present study, ten Microcystis morphospecies were identified in waterblooms of seven Chinese waterbodies, and Microcystis wesenbergii was shown as the dominant species in these waters. More than 250 single colonies of M. wesenbergii were chosen, under morphological identification, to examine whether M. wesenbergii produce hepatotoxic microcystin by using multiplex PCR for molecular detection of a region (mcyA) of microcystin synthesis genes, and chemical analyses of microcystin content by ELISA and HPLC for 21 isolated strains of M. wesenbergii from these waters were also performed. Both molecular and chemical methods demonstrated that M. wesenbergii from Chinese waters did not produce microcystin. - Both molecular and chemical methods demonstrated that Microcystis wesenbergii was not a microcystin producer in Chinese waters

  14. Recreational exposure to low concentrations of microcystins during an algal bloom in a small lake.

    Science.gov (United States)

    Backer, Lorraine C; Carmichael, Wayne; Kirkpatrick, Barbara; Williams, Christopher; Irvin, Mitch; Zhou, Yue; Johnson, Trisha B; Nierenberg, Kate; Hill, Vincent R; Kieszak, Stephanie M; Cheng, Yung-Sung

    2008-06-26

    We measured microcystins in blood from people at risk for swallowing water or inhaling spray while swimming, water skiing, jet skiing, or boating during an algal bloom. We monitored water samples from a small lake as a Microcystis aeruginosa bloom developed. We recruited 97 people planning recreational activities in that lake and seven others who volunteered to recreate in a nearby bloom-free lake. We conducted our field study within a week of finding a 10-microg/L microcystin concentration. We analyzed water, air, and human blood samples for water quality, potential human pathogens, algal taxonomy, and microcystin concentrations. We interviewed study participants for demographic and current health symptom information. Water samples were assayed for potential respiratory viruses (adenoviruses and enteroviruses), but none were detected. We did find low concentrations of Escherichia coli, indicating fecal contamination. We found low levels of microcystins (2 microg/L to 5 microg/L) in the water and (<0.1 ng/m(3)) in the aerosol samples. Blood levels of microcystins for all participants were below the limit of detection (0.147 microg/L). Given this low exposure level, study participants reported no symptom increases following recreational exposure to microcystins. This is the first study to report that water-based recreational activities can expose people to very low concentrations of aerosol-borne microcystins; we recently conducted another field study to assess exposures to higher concentrations of these algal toxins.

  15. [Survey on the contamination of microcystin-LR in water supply of Shanghai city].

    Science.gov (United States)

    Wu, He-yan; Zheng, Li-xing; Su, Jin; Shi, Wei

    2005-03-01

    To study the pollution level of microcystin-LR in water supply of Shanghai city and the removal efficacy for microcystin-LR through routine water treatment technique. High performance liquid chromatogram (HPLC) was applied to determine the concentration of microcystin-LR in source water, water samples after various water treatment procedures and tap water. The concentration of microcystin-LR varied with sampling seasons and sites and reached peak during summer and fall. The maximum of microcystin-LR was 2.38 microg/L in source water. Coagulation plus chlorine disinfection were found to be effective for the removal of microcystin-LR, while the remove rate through filtration was not significant. And it could also be detected in tap water as high as 1.27 microg/L. The source waters of Shanghai city were polluted by cyanobacteria toxins represented by microcystin-LR. The source water in suburb was more polluted. Routine water treatment techniques can not remove the toxins effectively.

  16. Production and characterization of Lemna minor bio-char and its catalytic application for biogas reforming

    International Nuclear Information System (INIS)

    Muradov, Nazim; Fidalgo, Beatriz; Gujar, Amit C.; Garceau, Nathaniel; T-Raissi, Ali

    2012-01-01

    Pyrolysis of fast-growing aquatic biomass - Lemna minor (commonly known as duckweed) with the emphasis on production, characterization and catalytic application of bio-char is reported in this paper. The yield of bio-char was determined as a function of L. minor pyrolysis temperature and sweep gas flow rate. It was found that the pore development during L. minor pyrolysis was not significant and the changes in the reaction conditions (temperature and sweep gas flow rate) did not alter markedly the textural characteristics and BET surface area of the bio-char produced. Thermogravimetric/differential thermogravimetric (TG/DTG) analyses of L. minor and different bio-char samples in inert (helium) and oxidative (air) media showed substantial differences in their TG/DTG patterns. A comparison of scanning electron micrographs (SEM) of L. minor, bio-char and ash indicated that the basic structural features of L. minor remained intact and were not affected by thermolysis. The inorganic ash content of L. minor derived bio-char is significantly higher than that of typical terrestrial (plant) biomass. The energy dispersive spectroscopic (EDS) analysis of L. minor ash showed that it mostly consisted of silica, and small quantities of Na, K and Ca compounds. The treatment of bio-char with CO 2 at 800 °C increased its BET surface area. It was found that CO 2 -treated bio-char exhibited appreciable initial catalytic activity in biogas reforming. -- Highlights: ► New data on characterization of bio-chars derived from Lemna minor are presented. ► Effect of pyrolysis operational parameters on bio-char properties is determined. ► Basic skeletal structure of Lemna minor leaflets does not change during pyrolysis. ► Bio-chars show an appreciable initial catalytic activity for biogas reforming.

  17. Comparative sensitivity of Selenastrum capricornutum and Lemna minor to sixteen herbicides

    Science.gov (United States)

    Fairchild, J.F.; Ruessler, D.S.; Haverland, P.S.; Carlson, A.R.

    1997-01-01

    Aquatic plant toxicity tests are frequently conducted in environmental risk assessments to determine the potential impacts of contaminants on primary producers. An examination of published plant toxicity data demonstrates that wide differences in sensitivity can occur across phylogenetic groups of plants. Yet relatively few studies have been conducted with the specific intent to compare the relative sensitivity of various aquatic plant species to contaminants. We compared the relative sensitivity of the algae Selenestrum capricornutum and the floating vascular plant Lemna minor to 16 herbicides (atrazine, metribuzin, simazine, cyanazine, alachlor, metolachlor, chlorsulfuron, metsulfuron, triallate, EPTC, trifluralin, diquat, paraquat, dicamba, bromoxynil, and 2,4-D). The herbicides studied represented nine chemical classes and several modes of action and were chosen to represent major current uses in the United States. Both plant species were generally sensitive to the triazines (atrazine, metribuzin, simazine, and cyanazine), sulfonureas (metsulfuron and chlorsulfuron), pyridines (diquat and paraquat), dinitroaniline (trifluralin), and acetanilide (alachlor and metolachlor) herbicides. Neither plant species was uniformly more sensitive than the other across the broad range of herbicides tested. Lemna was more sensitive to the sulfonureas (metsulfuron and chlorsulfuron) and the pyridines (diquat and parequat) than Selenastrum. However Selenastrum was more sensitive than Lemna to one of two thiocarbamates (triallate) and one of the triazines (cyanazine). Neither species was sensitive to selective broadleaf herbicides including bromoxynil, EPTC, dicamba, or 2,4-D. Results were not always predictable in spite of obvious differences in herbicide modes of action and plant phylogeny. Major departures in sensitivity of Selenastrum occurred between chemicals within individual classes of the triazine, acetanilide, and thiocarbamate herbicides. Results indicate that neither

  18. Detoxification of microcystin-LR in water by Portulaca oleracea cv.

    Science.gov (United States)

    Isobe, Takatoshi; Okuhata, Hiroshi; Miyasaka, Hitoshi; Jeon, Bong-Seok; Park, Ho-Dong

    2014-03-01

    Microcystin-LR (0.02 μg/ml) in the hydroculture medium of Portulaca oleracea cv., became below the detection level (<0.0001 μg/ml) by HPLC analysis after 7 days. The toxicity of microcystin estimated with protein phosphatase inhibition assay, however, remained at 37% of the initial level, indicating that microcystin-LR was transformed by P. oleracea cv. into unknown compound(s) of lower toxicity. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  19. LA LENTEJA DE AGUA (LEMNA MINOR L.: UNA PLANTA ACUÁTICA PROMISORIA*

    Directory of Open Access Journals (Sweden)

    María del Pilar Arroyave

    Full Text Available Se describen las principales características morfológicas y ecológicas de la planta acuática Lemna minor L., al igual que la utilización que tiene como complemento alimenticio para animales domésticos y en labores de fitorremediación, por su capacidad de absorber nutrientes y contaminantes de los ecosistemas acuáticos. Asimismo se discute su potencial como una especie adecuada para realizar ensayos de fitotoxicidad.

  20. Ecotoxicological assessments show sucralose and fluoxetine affect the aquatic plant, Lemna minor

    International Nuclear Information System (INIS)

    Amy-Sagers, Cherisse; Reinhardt, Keith; Larson, Danelle M.

    2017-01-01

    Highlights: • Sucralose increased leaf area and photosynthetic capacity of Lemna minor. • Sucralose increased δ 13 C of Lemna, indicating substantial uptake and assimilation. • 100 μg/L-fluoxetine decreased Lemna minor growth and asexual reproduction. - Abstract: Pharmaceuticals and personal care products (PPCP) are prevalent in aquatic systems, yet the fate and impacts on aquatic plants needs quantification for many compounds. We measured and detected sucralose (an artificial sweetener), fluoxetine (an antidepressant), and other PPCP in the Portneuf River in Idaho, USA, where Lemna minor (an aquatic plant in the environment and used in ecotoxicology studies) naturally occurs. Sucralose was hypothesized to negatively affect photosynthesis and growth of L. minor because sucralose is a chlorinated molecule that may be toxic or unusable for plant metabolism. A priori hypotheses were not created for fluoxetine due to lack of previous studies examining its impacts on plants. We conducted laboratory ecotoxicological assessments for a large range of concentrations of sucralose and fluoxetine on L. minor physiology and photosynthetic function. Frond green leaf area, root length, growth rate, photosynthetic capacity, and plant carbon isotopic composition (discrimination relative to a standard; δ 13 C) were measured among treatments ranging from 0 to 15000 nmol/L-sucralose and 0–323 nmol/L-fluoxetine. Contrary to our predictions, sucralose significantly increased green leaf area, photosynthetic capacity, and δ 13 C of L. minor at environmentally relevant concentrations. The increase of δ 13 C from sucralose amendments and an isotope-mixing model indicated substantial sucralose uptake and assimilation within the plant. Unlike humans who cannot break down and utilize sucralose, we documented that L. minor—a mixotrophic plant—can use sucralose as a sugar substitute to increase its green leaf area and photosynthetic capacity. Fluoxetine significantly decreased L

  1. Ecotoxicological assessments show sucralose and fluoxetine affect the aquatic plant, Lemna minor

    Energy Technology Data Exchange (ETDEWEB)

    Amy-Sagers, Cherisse; Reinhardt, Keith; Larson, Danelle M., E-mail: danellelarson77@gmail.com

    2017-04-15

    Highlights: • Sucralose increased leaf area and photosynthetic capacity of Lemna minor. • Sucralose increased δ {sup 13}C of Lemna, indicating substantial uptake and assimilation. • 100 μg/L-fluoxetine decreased Lemna minor growth and asexual reproduction. - Abstract: Pharmaceuticals and personal care products (PPCP) are prevalent in aquatic systems, yet the fate and impacts on aquatic plants needs quantification for many compounds. We measured and detected sucralose (an artificial sweetener), fluoxetine (an antidepressant), and other PPCP in the Portneuf River in Idaho, USA, where Lemna minor (an aquatic plant in the environment and used in ecotoxicology studies) naturally occurs. Sucralose was hypothesized to negatively affect photosynthesis and growth of L. minor because sucralose is a chlorinated molecule that may be toxic or unusable for plant metabolism. A priori hypotheses were not created for fluoxetine due to lack of previous studies examining its impacts on plants. We conducted laboratory ecotoxicological assessments for a large range of concentrations of sucralose and fluoxetine on L. minor physiology and photosynthetic function. Frond green leaf area, root length, growth rate, photosynthetic capacity, and plant carbon isotopic composition (discrimination relative to a standard; δ{sup 13}C) were measured among treatments ranging from 0 to 15000 nmol/L-sucralose and 0–323 nmol/L-fluoxetine. Contrary to our predictions, sucralose significantly increased green leaf area, photosynthetic capacity, and δ {sup 13}C of L. minor at environmentally relevant concentrations. The increase of δ {sup 13}C from sucralose amendments and an isotope-mixing model indicated substantial sucralose uptake and assimilation within the plant. Unlike humans who cannot break down and utilize sucralose, we documented that L. minor—a mixotrophic plant—can use sucralose as a sugar substitute to increase its green leaf area and photosynthetic capacity. Fluoxetine

  2. Significance of microcystin production by benthic communities in water treatment systems of arid zones.

    Science.gov (United States)

    Hurtado, I; Aboal, M; Zafra, E; Campillo, D

    2008-02-01

    The study of the dynamics of phytobenthic and phytoplankton communities was undertaken, during a year, in the regulation reservoir associated with a water treatment plant (WTP), which provides the city of Murcia (Spain) with drinking water. Water samples were collected in different stages of the treatment. In the reservoir, the presence of dissolved and intracellular microcystins is constant, both in benthos and in plankton. The collected samples show a positive correlation between the dissolved microcystins and the benthic ones in the reservoir itself, as well as in an upstream reservoir (Ojós Reservoir). The treatment process (ozone+clarification+ozone+activated carbon) is very effective in the removal of toxins, and the drinking water produced is totally free of microcystins. The incorporation of the benthic communities in the routine check for the presence of microcystins is recommended, since it is not compulsory according to the current legislation.

  3. Impacts of microcystin, a cyanobacterial toxin, on laboratory rodents in vivo

    Czech Academy of Sciences Publication Activity Database

    Ziková, Andrea; Kopp, Radovan

    2008-01-01

    Roč. 56, č. 5 (2008), s. 263-273 ISSN 1211-8516 Institutional research plan: CEZ:AV0Z60050516 Keywords : microcystin * mice, rats * intraperitoneal, oral, intratracheal application Subject RIV: EF - Botanics

  4. Production of cyanopeptolins, anabaenopeptins, and microcystins by the harmful cyanobacteria Anabaena 90 and Microcystis PCC 7806

    NARCIS (Netherlands)

    Tonk, L.; Welker, M.; Huisman, J.; Visser, P.M.

    2009-01-01

    This study investigated the effects of light intensity, temperature, and phosphorus limitation on the peptide production of the cyanobacteria Microcystis PCC 7806 and Anabaena 90. Microcystis PCC 7806 produced two microcystin variants and three cyanopeptolins, whereas Anabaena 90 produced four

  5. Iron based sustainable greener technologies to treat cyanobacteria and microcystin-LR in water

    Czech Academy of Sciences Publication Activity Database

    Sharma, V. K.; Chen, L.; Maršálek, Blahoslav; Zbořil, R.; O'Shea, K. E.; Dionysiou, D. D.

    2017-01-01

    Roč. 17, č. 1 (2017), s. 107-114 ISSN 1606-9749 Institutional support: RVO:67985939 Keywords : detoxification * microcystin * oxidation Subject RIV: CC - Organic Chemistry OBOR OECD: Environmental biotechnology Impact factor: 0.573, year: 2016

  6. Diversidade e estrutura da comunidade bacteriana associada às armadilhas da planta carnívora Utricularia gibba (Lentibulariaceae) e ao ambiente aquático.

    OpenAIRE

    Almir José Ferreira

    2011-01-01

    A diversidade microbiana em ambientes aquáticos e sua associação com plantas carnívoras ainda é pouco estudada. Assim, a comunidade bacteriana da planta carnívora Utricularia gibba e do seu meio aquático foi avaliada por meio do seqüenciamento em larga escala (454 Roche) de uma biblioteca do gene 16S rRNA. Os resultados indicaram que a comunidade bacteriana na água é significativamente diferente da comunidade dos utrículos. Além disso, a comunidade bacteriana da água é composta principalmente...

  7. Overexpression of Nrf2 protects against microcystin-induced hepatotoxicity in mice.

    Directory of Open Access Journals (Sweden)

    Yuan-Fu Lu

    Full Text Available Oxidative stress and glutathione (GSH depletion are implicated in mycocystin hepatotoxicity. To investigate the role of nuclear factor erythroid 2-related factor 2 (Nrf2 in microcystin-induced liver injury, Nrf2-null, wild-type, and Keap1-hepatocyte knockout (Keap1-HKO mice were treated with microcystin (50 μg/kg, i.p.. Blood and liver samples were collected 8 h thereafter. Microcystin increased serum alanine aminotransferase and aspartate aminotransferase activities, and caused extensive inflammation and necrosis in Nrf2-null and wild-type mice, but not in Keap1-HKO mice. Oxidative stress and inflammation are implicated in microcystin-induced hepatotoxicity, as evidenced by increased lipid peroxidation and increased expression of pro-inflammatory genes, such as neutrophil-specific chemokines mKC and MIP-2, and pro-inflammatory cytokines IL-1β and IL-6. The increased expression of these pro-inflammatory genes was attenuated in Keap1-HKO mice. Nrf2 and Nqo1 mRNA and protein were higher in Keap1-HKO mice at constitutive levels and after microcystin. To further investigate the mechanism of the protection, hepatic GSH and the mRNA of GSH-related enzymes were determined. Microcystin markedly depleted liver GSH by 60-70% in Nrf2 and WT mice but only 35% in Keap1-HKO mice. The mRNAs of GSH conjugation and peroxide reduction enzymes, such as Gstα1, Gstα4, Gstμ, and Gpx2 were higher in livers of Keap1-HKO mice, together with higher expression of the rate-limiting enzyme for GSH synthesis (Gclc. Organic anion transport polypeptides were increased by microcystin with the most increase in Keap1-HKO mice. In conclusion, this study demonstrates that higher basal levels of Nrf2 and GSH-related genes in Keap1-HKO mice prevented microcystin-induced oxidative stress and liver injury.

  8. Hepatotoxic Seafood Poisoning (HSP Due to Microcystins: A Threat from the Ocean?

    Directory of Open Access Journals (Sweden)

    Evangelos Briasoulis

    2013-08-01

    Full Text Available Cyanobacterial blooms are a major and growing problem for freshwater ecosystems worldwide that increasingly concerns public health, with an average of 60% of blooms known to be toxic. The most studied cyanobacterial toxins belong to a family of cyclic heptapeptide hepatotoxins, called microcystins. The microcystins are stable hydrophilic cyclic heptapeptides with a potential to cause cell damage following cellular uptake via organic anion-transporting proteins (OATP. Their intracellular biologic effects presumably involve inhibition of catalytic subunits of protein phosphatases (PP1 and PP2A and glutathione depletion. The microcystins produced by cyanobacteria pose a serious problem to human health, if they contaminate drinking water or food. These toxins are collectively responsible for human fatalities, as well as continued and widespread poisoning of wild and domestic animals. Although intoxications of aquatic organisms by microcystins have been widely documented for freshwater ecosystems, such poisonings in marine environments have only occasionally been reported. Moreover, these poisonings have been attributed to freshwater cyanobacterial species invading seas of lower salinity (e.g., the Baltic or to the discharge of freshwater microcystins into the ocean. However, recent data suggest that microcystins are also being produced in the oceans by a number of cosmopolitan marine species, so that Hepatotoxic Seafood Poisoning (HSP is increasingly recognized as a major health risk that follows consumption of contaminated seafood.

  9. Effects of microcystins contamination on soil enzyme activities and microbial community in two typical lakeside soils.

    Science.gov (United States)

    Cao, Qing; Steinman, Alan D; Su, Xiaomei; Xie, Liqiang

    2017-12-01

    A 30-day indoor incubation experiment was conducted to investigate the effects of different concentrations of microcystin (1, 10, 100 and 1000 μg eq. MC-LR L -1 ) on soil enzyme activity, soil respiration, physiological profiles, potential nitrification, and microbial abundance (total bacteria, total fungi, ammonia-oxidizing bacteria and archaea) in two lakeside soils in China (Soil A from the lakeside of Lake Poyanghu at Jiujiang; Soil B from the lakeside of Lake Taihu at Suzhou). Of the enzymes tested, only phenol oxidase activity was negatively affected by microcystin application. In contrast, dehydrogenase activity was stimulated in the 1000 μg treatment, and a stimulatory effect also occurred with soil respiration in contaminated soil. The metabolic profiles of the microbial communities indicated that overall carbon metabolic activity in the soils treated with high microcystin concentrations was inhibited, and high concentrations of microcystin also led to different patterns of potential carbon utilization. High microcystin concentrations (100, 1000 μg eq. MC-LR L -1 in Soil A; 10, 100 1000 μg eq. MC-LR L -1 in Soil B) significantly decreased soil potential nitrification rate. Furthermore, the decrease in soil potential nitrification rate was positively correlated with the decrease of the amoA gene abundance, which corresponds to the ammonia-oxidizing bacterial community. We conclude that application of microcystin-enriched irrigation water can significantly impact soil microbial community structure and function. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Effects of adsorption to plastics and solvent conditions in the analysis of the cyanobacterial toxin microcystin-LR by high performance liquid chromatography.

    Science.gov (United States)

    Hyenstrand, P; Metcalf, J S; Beattie, K A; Codd, G A

    2001-10-01

    Effects of adsorption to plastics and solvent conditions in the high performance liquid chromatographic analysis of the cyanobacterial toxin microcystin-LR were investigated. Aqueous microcystin-LR readily adsorbed to the disposable polypropylene pipette tips commonly used in laboratory manipulations. This was not affected by the pH or salinity of the solution. Furthermore, dilutions of microcystin-LR in varying concentrations of methanol and acetonitrile influenced the quantification of the microcystin-LR concentration by high performance liquid chromatography.

  11. An overview of the accumulation of microcystins in aquatic ecosystems.

    Science.gov (United States)

    Pham, Thanh-Luu; Utsumi, Motoo

    2018-05-01

    Cyanotoxins produced by toxic cyanobacteria pose a major, worldwide environmental threat to freshwater ecosystems. Microcystins (MCs) are considered to be the most hazardous groups. Indeed, some of the largest aquatic ecosystems on the earth are being contaminated with MCs. Questions have arisen regarding their transfer and bioaccumulation in natural environment. This review summarizes the present state of knowledge regarding toxic cyanobacteria and MCs, with a specific focus on their distribution in different components of aquatic ecosystems. Their accumulation in water columns, aquatic animals, plants, and sediments is summarized. MCs have been contaminating all areas of the aquatic ecosystems. Of these, the water column was the most contaminated with MCs and served as an intermediate transmission substation. Via this route, MCs could enter to other stations such as sediment, animals, aquatic and terrestrial plants. Therefore, the use of water contaminated with MCs may induce food chain contaminations with considerable health risks. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Recreational Exposure to Low Concentrations of Microcystins During an Algal Bloom in a Small Lake

    Directory of Open Access Journals (Sweden)

    Yung-Sung Cheng

    2008-06-01

    Full Text Available We measured microcystins in blood from people at risk for swallowing water or inhaling spray while swimming, water skiing, jet skiing, or boating during an algal bloom. We monitored water samples from a small lake as a Microcystis aeruginosa bloom developed. We recruited 97 people planning recreational activities in that lake and seven others who volunteered to recreate in a nearby bloom-free lake. We conducted our field study within a week of finding a 10-μg/L microcystin concentration. We analyzed water, air, and human blood samples for water quality, potential human pathogens, algal taxonomy, and microcystin concentrations. We interviewed study participants for demographic and current health symptom information. Water samples were assayed for potential respiratory viruses (adenoviruses and enteroviruses, but none were detected. We did find low concentrations of Escherichia coli, indicating fecal contamination. We found low levels of microcystins (2 μg/L to 5 μg/L in the water and (<0.1 ng/m3 in the aerosol samples. Blood levels of microcystins for all participants were below the limit of detection (0.147μg/L. Given this low exposure level, study participants reported no symptom increases following recreational exposure to microcystins. This is the first study to report that water-based recreational activities can expose people to very low concentrations of aerosol-borne microcystins; we recently conducted another field study to assess exposures to higher concentrations of these algal toxins.

  13. Evidence for positive selection acting on microcystin synthetase adenylation domains in three cyanobacterial genera

    Directory of Open Access Journals (Sweden)

    Rouhiainen Leo

    2008-09-01

    Full Text Available Abstract Background Cyanobacteria produce a wealth of secondary metabolites, including the group of small cyclic heptapeptide hepatotoxins that constitutes the microcystin family. The enzyme complex that directs the biosynthesis of microcystin is encoded in a single large gene cluster (mcy. mcy genes have a widespread distribution among cyanobacteria and are likely to have an ancient origin. The notable diversity within some of the Mcy modules is generated through various recombination events including horizontal gene transfer. Results A comparative analysis of the adenylation domains from the first module of McyB (McyB1 and McyC in the microcystin synthetase complex was performed on a large number of microcystin-producing strains from the Anabaena, Microcystis and Planktothrix genera. We found no decisive evidence for recombination between strains from different genera. However, we detected frequent recombination events in the mcyB and mcyC genes between strains within the same genus. Frequent interdomain recombination events were also observed between mcyB and mcyC sequences in Anabaena and Microcystis. Recombination and mutation rate ratios suggest that the diversification of mcyB and mcyC genes is driven by recombination events as well as point mutations in all three genera. Sequence analysis suggests that generally the adenylation domains of the first domain of McyB and McyC are under purifying selection. However, we found clear evidence for positive selection acting on a number of amino acid residues within these adenylation domains. These include residues important for active site selectivity of the adenylation domain, strongly suggesting selection for novel microcystin variants. Conclusion We provide the first clear evidence for positive selection acting on amino acid residues involved directly in the recognition and activation of amino acids incorporated into microcystin, indicating that the microcystin complement of a given strain may

  14. Estimating microcystin levels at recreational sites in western Lake Erie and Ohio

    Science.gov (United States)

    Francy, Donna S.; Brady, Amie M. G.; Ecker, Christopher D.; Graham, Jennifer L.; Stelzer, Erin A.; Struffolino, Pamela; Loftin, Keith A.

    2016-01-01

    Cyanobacterial harmful algal blooms (cyanoHABs) and associated toxins, such as microcystin, are a major global water-quality issue. Water-resource managers need tools to quickly predict when and where toxin-producing cyanoHABs will occur. This could be done by using site-specific models that estimate the potential for elevated toxin concentrations that cause public health concerns. With this study, samples were collected at three Ohio lakes to identify environmental and water-quality factors to develop linear-regression models to estimate microcystin levels. Measures of the algal community (phycocyanin, cyanobacterial biovolume, and cyanobacterial gene concentrations) and pH were most strongly correlated with microcystin concentrations. Cyanobacterial genes were quantified for general cyanobacteria, general Microcystis and Dolichospermum, and for microcystin synthetase (mcyE) for Microcystis, Dolichospermum, and Planktothrix. For phycocyanin, the relations were different between sites and were different between hand-held measurements on-site and nearby continuous monitor measurements for the same site. Continuous measurements of parameters such as phycocyanin, pH, and temperature over multiple days showed the highest correlations to microcystin concentrations. The development of models with high R2values (0.81–0.90), sensitivities (92%), and specificities (100%) for estimating microcystin concentrations above or below the Ohio Recreational Public Health Advisory level of 6 μg L−1 was demonstrated for one site; these statistics may change as more data are collected in subsequent years. This study showed that models could be developed for estimates of exceeding a microcystin threshold concentration at a recreational freshwater lake site, with potential to expand their use to provide relevant public health information to water resource managers and the public for both recreational and drinking waters.

  15. Wastewater pollution remediation: an experimental investigation with aquatic macrophyte Lemna minor.

    Science.gov (United States)

    Kuraishi, M A; Sharma, Sunil

    2011-04-01

    The freshwater resources are shrinking rapidly due to rise in population and discharge of untreated wastewater into fresh water bodies making them unfit for public use in many developing countries. Effective and affordable wastewater treatment has become a challenge, hence various alternatives are being investigated by researchers to tackle the problem. In this study, laboratory scale experiments on duckweed covered domestic sewage were carried out to evaluate the removal efficiency of duckweed species Lemna minor as a domestic wastewater stripper. The outdoor experiments were conducted in 4 mini ponds at Jodhpur, popularly known as Sun City of India. The physico-chemical properties of domestic wastewater were evaluated before and after inoculation of culture for wastewater quality improvement. Various parameters, namely pH, DO, TSS, TDS, Turbidity, BOD, COD, Total Nitrogen and Total Phosphorus were analysed for varying detention periods. The result indicated that the treated effluent can be used for irrigation.

  16. Temperature-dependent toxicity of artemisinin toward the macrophyte Lemna minor and the algae Pseudokirchneriella subcapitata

    DEFF Research Database (Denmark)

    Jessing, Karina Knudsmark; Andresen, Marianne; Cedergreen, Nina

    2014-01-01

    - and groundwater. To make better risk assessments of A. annua which is cultivated under varying climatic conditions, the temperature-dependent toxicity of artemisinin toward the green algae Pseudokirchneriella subcapitata and the macrophyte Lemna minor was evaluated at temperatures ranging from 10 to 30°C....... To include a possible effect of temperature on the degradation rate of artemisinin, artemisinin concentrations were measured during the experiment and toxicity was related to the time-weighted averages of exposure concentrations. The toxicity of artemisinin toward the macrophyte L. minor and the algae P......Artemisinin, an antimalarial compound derivated from the cultivated plant Artemisia annua L., is produced in situ through cultivation of A. annua under different climatic conditions. The bioactive compound artemisinin has been observed to spread to the surroundings as well as to leach to surface...

  17. Biodiesel production from Jatropha curcas L. oil using Lemna perpusilla Torrey ash as heterogeneous catalyst

    International Nuclear Information System (INIS)

    Chouhan, Ashish Pratap Singh; Sarma, Anil Kumar

    2013-01-01

    Refined Jatropha curcas L. oil (JCO) and methanol were used as the reactants for the transesterification reactions in a Radleys reactor in the presence of a heterogeneous ash catalyst derived from the waste aquatic plant Lemna perpusilla Torrey. Physical characterization of the catalyst showed partly crystalline behaviour and a moderate surface area 9.622 m 2 g −1 . The L. perpusilla Torrey ashes obtained from traditional combustion method were further calcined at 550 ± 5 °C before use. In addition to other non-metal and metallic constitutes the ash contains 11.3% potassium which attributed to its catalytic behaviour. The cumulative mass fraction of 89.43% of the oil was converted to biodiesel at 65 ± 5 °C in 5 h at 1:9 M ratio of oil to alcohol with 5% of the ash as catalyst. The biodiesel (FAME) so obtained were characterized using appropriate ASTM methods and found within the defined standard limits. The catalyst could be reused upto 3-times but there is a reduction of efficacy by about 25% for 3rd consecutive batch reaction. The activation energy was calculated for FAME and found to be 29.49 kJ mol −1 . -- Highlights: ► Lemna perpusilla Torrey ash is a potential heterogeneous catalyst. ► The catalyst has moderately good surface area and pores. ► The ash contain 11.3% potassium which is attributed to its catalytic behaviour. ► 89.43% of the refined Jatropha curcas oil could be converted to FAME in a Radleys reactor. ► The activation energy for FAME was calculated and found to be 29.49 kJ mol −1

  18. Effects of physicochemical variables and cyanobacterial extracts on the immunoassay of microcystin-LR by two ELISA kits.

    Science.gov (United States)

    Metcalf, J S; Hyenstrand, P; Beattie, K A; Codd, G A

    2000-09-01

    Two types of commercially available ELISA kits for the immunoassay of cyanobacterial microcystins were evaluated for potential interference effects due to methanol, salinity, pH, plasticware and cyanobacterial extract. Of the treatments examined, methanol had the greatest effect, giving false positive microcystin concentrations with increasing methanol concentrations up to 30% (v/v) compared with the negative calibrators of each kit. False positive microcystin results were also produced with increasing salinity up to full strength seawater. Decreases in microcystin-LR equivalents were observed when assaying purified microcystin-LR at pH values between 6.25 and 10. Aqueous microcystin-LR solutions in plastic microcentrifuge tubes after pipetting with disposable plastic tips had lower toxin concentrations than expected when analysed by ELISA. Indicated microcystin concentrations in cyanobacterial extracts varied between kit types and the choice of blanks used. Although ELISAs can be useful tools for the screening of water and cyanobacterial blooms for microcystins and nodularins, users should be aware that commercial kits can be susceptible to interference by commonly encountered environmental and laboratory conditions and materials.

  19. Retention of Microcystis aeruginosa and microcystin by salad lettuce (Lactuca sativa) after spray irrigation with water containing cyanobacteria.

    Science.gov (United States)

    Codd, G A; Metcalf, J S; Beattie, K A

    1999-08-01

    Colonies and single cells of Microcystis aeruginosa and the hepatotoxin microcystin were retained by salad lettuce after growth with spray irrigation water containing the microcystin-producing cyanobacteria. These findings are discussed in terms of crop spray irrigation with water containing cyanobacteria and potential human exposure to cyanobacterial toxins via plant foods grown in such circumstances.

  20. The Effect of Cyanobacterial Biomass Enrichment by Centrifugation and GF/C Filtration on Subsequent Microcystin Measurement

    Directory of Open Access Journals (Sweden)

    Shelley Rogers

    2015-03-01

    Full Text Available Microcystins are cyclic peptides produced by multiple cyanobacterial genera. After accumulation in the liver of animals they inhibit eukaryotic serine/threonine protein phosphatases, causing liver disease or death. Accurate detection/quantification of microcystins is essential to ensure safe water resources and to enable research on this toxin. Previous methodological comparisons have focused on detection and extraction techniques, but have not investigated the commonly used biomass enrichment steps. These enrichment steps could modulate toxin production as recent studies have demonstrated that high cyanobacterial cell densities cause increased microcystin levels. In this study, three microcystin-producing strains were processed using no cell enrichment steps (by direct freezing at three temperatures and with biomass enrichment (by centrifugation or GF/C filtration. After extraction, microcystins were analyzed using liquid chromatography-tandem mass spectrometry. All processing methods tested, except GF/C filtration, resulted in comparable microcystin quotas for all strains. The low yields observed for the filtration samples were caused by adsorption of arginine-containing microcystins to the GF/C filters. Whilst biomass enrichment did not affect microcystin metabolism over the time-frame of normal sample processing, problems associated with GF/C filtration were identified. The most widely applicable processing method was direct freezing of samples as it could be utilized in both field and laboratory environments.

  1. The Effect of Cyanobacterial Biomass Enrichment by Centrifugation and GF/C Filtration on Subsequent Microcystin Measurement

    Science.gov (United States)

    Rogers, Shelley; Puddick, Jonathan; Wood, Susanna A.; Dietrich, Daniel R.; Hamilton, David P.; Prinsep, Michele R.

    2015-01-01

    Microcystins are cyclic peptides produced by multiple cyanobacterial genera. After accumulation in the liver of animals they inhibit eukaryotic serine/threonine protein phosphatases, causing liver disease or death. Accurate detection/quantification of microcystins is essential to ensure safe water resources and to enable research on this toxin. Previous methodological comparisons have focused on detection and extraction techniques, but have not investigated the commonly used biomass enrichment steps. These enrichment steps could modulate toxin production as recent studies have demonstrated that high cyanobacterial cell densities cause increased microcystin levels. In this study, three microcystin-producing strains were processed using no cell enrichment steps (by direct freezing at three temperatures) and with biomass enrichment (by centrifugation or GF/C filtration). After extraction, microcystins were analyzed using liquid chromatography-tandem mass spectrometry. All processing methods tested, except GF/C filtration, resulted in comparable microcystin quotas for all strains. The low yields observed for the filtration samples were caused by adsorption of arginine-containing microcystins to the GF/C filters. Whilst biomass enrichment did not affect microcystin metabolism over the time-frame of normal sample processing, problems associated with GF/C filtration were identified. The most widely applicable processing method was direct freezing of samples as it could be utilized in both field and laboratory environments. PMID:25763766

  2. Effects of microcystin-free and Microcystin containing strains of the cyanobacterium Microcystis aeruginosa on growth of the grazer Daphnia magna

    NARCIS (Netherlands)

    Lürling, M.

    2003-01-01

    Harmful effects of the common bloom-forming cyanobacterium Microcystis aeruginosa on the grazer Daphnia have been explained from morphological features, nutritional insufficiency, and the production of toxins called microcystins. The effects of four M. aeruginosa strains, including one free of

  3. Dynamics of Total Microcystin LR Concentration in Three Subtropical Hydroelectric Generation Reservoirs in Uruguay, South America.

    Science.gov (United States)

    González-Piana, Mauricio; Fabián, Daniel; Piccardo, Andrea; Chalar, Guillermo

    2017-10-01

    This study analyzed the temporal dynamics of total microcystin LR concentrations between the years of 2012 and 2015 in the Bonete, Baygorria and Palmar hydroelectric generation reservoirs in the central region of the Negro River, Uruguay. The three reservoirs showed differents total microcystin LR concentration, with no significant differences among them. Over 20 sampling dates, the three reservoirs exhibited total microcystin LR concentrations on eight occasions that corresponded to a slight to moderate human health risk according to WHO guideline values for recreational waters. By determining the concentration of microcystin LR in cyanobacterial biomass, we identified cyanobacterial populations that occurred over time with varying degrees of toxin production (maximal 85.4 µg/mm 3 ). The microcystin LR concentration in Bonete was positively correlated with temperature (r = 0.587) and cyanobacterial biomass (r = 0.736), in Baygorria with cyanobacterial biomass (r = 0.521), and in Palmar with temperature (r = 0.500) and negatively correlated with ammonia (r = -0.492). Action is needed to reduce the presence of toxic cyanobacteria in these systems. A decrease in the use of agrochemicals and management changes in the reservoir basins could be successful long-term measures.

  4. Hepatotoxicity associated with microcystin/ Hepatotoxicidade associada à microcistina

    Directory of Open Access Journals (Sweden)

    Ana Paula Frederico Rodrigues Loureiro Bracarense

    2008-08-01

    Full Text Available Urban and industrial discharges, intense agricultural exploitation and fisheries have been causing the eutrophication in both drinking and recreational waters. A frequent consequence of eutrophication in waters is the massive development of cyanobacteria. The occurrence of these blooms induces a severe problem, as Microcystis aeruginosa, the most widespread distributed cyanobacteria, can produce microcystins (MC. Toxic effects of MC have been described in liver, lungs, stomach, and intestine. Deaths in wildlife, livestock and human beings were also associated with MC exposition. MC exposition can occurs directly by ingestion, inhalation, contact, intravenous inoculation of contaminated water (hemodialysis or indirectly, by the consumption of animals, as fish and mollusks, the majors ingestors of cyanobacteria and its toxins. The most toxic MC, an also the most common is microcystin-LR (MC-LR, that has the liver as the main target organ. Microcystin is taken up specifically into the liver by bile acid transporters and, after entering the cytoplasm, inhibit protein phosphatases 1 and 2A, which leads to the increase in protein phosphorylation. This effect has two main consequences: the destruction of cytoskeleton directly causing cytotoxic effects, and deregulation of cell division, leading to tumor-promoting activity. Acute exposition to MC induces severe intrahepatic hemorrhage, necrosis and apoptosis, while chronic exposure can cause hepatic or intestinal neoplasia. It has been documented that MC hepatotoxicity is closely associated with intracellular reactive oxygen species formation. Natural degradation of microcystins depends on the solar radiation and bacteria. If degradation is insufficient, MC will persist in the freshwater food chain. Microcystin contamination of waters is therefore a hazard to human and animal health, so efforts to avoid eutrophication of waters sources are essential, in order to minimize the risks to public health

  5. Sustainable biodegradation of phenol by Acinetobacter calcoaceticus P23 isolated from the rhizosphere of duckweed Lemna aoukikusa.

    Science.gov (United States)

    Yamaga, Fumiko; Washio, Kenji; Morikawa, Masaaki

    2010-08-15

    Phenol-degrading bacteria were isolated from the rhizosphere of duckweed (Lemna aoukikusa) using an enrichment culture method. One of the isolates, P23, exhibited an excellent ability to degrade phenol and attach to a solid surface under laboratory conditions. Phylogenetic analysis revealed that P23 belongs to the genera Acinetobacter and has the highest similarity to Acinetobacter calcoaceticus. P23 rapidly colonized on the surface of sterilized duckweed roots and formed biofilms, indicating that the conditions provided by the root system of duckweed are favorable to P23. A long-term performance test (160 h) showed that continuous removal of phenol can be attributed to the beneficial symbiotic interaction between duckweed and P23. P23 is the first growth-promoting bacterium identified from Lemna aoukikusa. The results in this study suggest the potential usefulness of dominating a particular bacterium in the rhizosphere of duckweeds to achieve efficient and sustainable bioremediation of polluted water.

  6. Influence of toxic cyanobacteria on community structure and microcystin accumulation of freshwater molluscs

    Energy Technology Data Exchange (ETDEWEB)

    Gerard, Claudia [ECOBIO, Universite de Rennes 1, CNRS, Avenue du General Leclerc, 35042 Rennes (France)], E-mail: claudia.gerard@univ-rennes1.fr; Poullain, Virginie [Department of Biological Sciences, University of Idaho, Moscow, ID 83844 (United States); Lance, Emilie [ECOBIO, Universite de Rennes 1, CNRS, Avenue du General Leclerc, 35042 Rennes (France); Acou, Anthony [ERT 52, Universite de Rennes 1, CNRS, Avenue du General Leclerc, 35042 Rennes (France); Brient, Luc; Carpentier, Alexandre [ECOBIO, Universite de Rennes 1, CNRS, Avenue du General Leclerc, 35042 Rennes (France)

    2009-02-15

    Community structure and microcystin accumulation of freshwater molluscs were studied before and after cyanobacterial proliferations, in order to assess the impact of toxic blooms on molluscs and the risk of microcystin transfer in food web. Observed decrease in mollusc abundance and changes in species richness in highly contaminated waters were not significant; however, relative abundances of taxa (prosobranchs, pulmonates, bivalves) were significantly different before and after cyanobacterial bloom. Pulmonates constituted the dominant taxon, and bivalves never occurred after bloom. Microcystin accumulation was significantly higher in molluscs from highly (versus lowly) contaminated waters, in adults (versus juveniles) and in pulmonates (versus prosobranchs and bivalves). Results are discussed according to the ecology of molluscs, their sensitivity and their ability to detoxify. - Proliferations of toxic cyanobacteria may alter the structure of mollusc communities with cyanotoxin accumulation depending on age and taxon.

  7. Influence of toxic cyanobacteria on community structure and microcystin accumulation of freshwater molluscs.

    Science.gov (United States)

    Gérard, Claudia; Poullain, Virginie; Lance, Emilie; Acou, Anthony; Brient, Luc; Carpentier, Alexandre

    2009-02-01

    Community structure and microcystin accumulation of freshwater molluscs were studied before and after cyanobacterial proliferations, in order to assess the impact of toxic blooms on molluscs and the risk of microcystin transfer in food web. Observed decrease in mollusc abundance and changes in species richness in highly contaminated waters were not significant; however, relative abundances of taxa (prosobranchs, pulmonates, bivalves) were significantly different before and after cyanobacterial bloom. Pulmonates constituted the dominant taxon, and bivalves never occurred after bloom. Microcystin accumulation was significantly higher in molluscs from highly (versus lowly) contaminated waters, in adults (versus juveniles) and in pulmonates (versus prosobranchs and bivalves). Results are discussed according to the ecology of molluscs, their sensitivity and their ability to detoxify.

  8. Tissue Distribution, Excretion, and Hepatic Biotransformation of Microcystin-LR in Mice

    Science.gov (United States)

    1990-07-09

    HOOSER, S. B., and HASCHEK, W. M.: Blue-green algae (Microcystis aeruginosa) hepatotoxicosis in dairy cows . Am. J. Vet. Res. 48: 1415-1420, 1987...number) The distribution, excretion, and hepatic metabolism of [3H]microcystin-LR ([3H]MCYST-LR, sublethal, i.v.) were measured in mice. Plasma... metabolism of [3H]microcystin-IR (L’H]MCYST-LR, subletnal, i.v.) were measured in mice. Plasma elimination was biexponential with a- and /- phase half-lives

  9. Impacts of microcystin, a cyanobacterial toxin, on laboratory rodents in vivo

    Directory of Open Access Journals (Sweden)

    Andrea Ziková

    2008-01-01

    Full Text Available Cyanobacterial water blooms became a global problem/issue because beside a dramatic deterioration of water quality parameters they also produce cyanobacterial toxins being harmful for animals and humans. Cyanotoxins especially the most prominent one, microcystin-LR (MC-LR, are of major concern and they have been reported to cause even death of mammals following ingestion or ingurgitation due to hepatotoxic modes of action. The aim of the recent study is to summarize briefly the impacts of microcystin on laboratory rodents, mice and rats, being used as models for other mammals including human beings. Most experimental approaches used intraperitoneal rather than oral and intratracheal application of microcystins, especially MC-LR, being the most efficient way to induce adverse impacts on different target organs. However, no matter how the exposure of rodents was performed, microcystins induced severe harmful impacts on the different target organs, preferentially the liver, for instances hemorrhages and apoptosis in liver, liver tumours, adverse effects on gut, kidney, testis and epididymis including spermatogenesis, on lung, on serum parameters and on progeny. In addition to these histological findings, microcystin was found to affect specifically biochemical parameters of target organs such as enzymes e.g. GST, CAT, GR, GPX, SOD, AST, ALT, γ-GT, protein phosphatases, SDH, SoDH and LDH or stress proteins such as HSP-70 and further parameters such as hepatic sulfhydryl content, GSH depletion, total bilirubin, urea nitrogen, and creatinine. Gene array analyses revealed that microcystin affects genes related to actin organization, cell cycle, apoptosis, cellular redox potential, cell signalling, albumin metabolism, glucose homeostasis pathway and organic anion transport polypeptide system. In combination with a further proteomics approach the proteomic analyses indicate that liver apoptosis induced by microcystin can be induced by two pathways: the

  10. Microcystin production in epiphytic cyanobacteria on submerged macrophytes.

    Science.gov (United States)

    Mohamed, Zakaria A; Al Shehri, Abdulrahman M

    2010-06-15

    Cyanotoxins have been largely studied in planktonic and benthic cyanobacteria, but microcystin (MCYST) production in epiphytic cyanobacteria has not been reported yet. The present study reports for the first time the MCYST production in epiphytic cyanobacteria on submerged macrophytes. During this study, four common submerged macrophytes in eutrophic pond in Saudi Arabia were surveyed for the presence of toxic epiphytic cyanobacteria. The results showed that chlorophyll-a and total biovolume of epiphytic cyanobacteria differed significantly among submerged plants with highest values obtained in Stratiotes aloides and lowest in Elodea canadensis. Epiphytic materials collected from Ceratophyllum demersum and S. aloides had higher species diversities than materials collected from E. canadensis and Myriophyllum verticillatum. The cyanobacteria, Merismopedia tenuissima and Leptolyngbya boryana were recorded with a high abundance in epiphytic materials collected from all submerged macrohpytes. Based on Enzyme-linked immunosorbent assay (ELISA), these two species were found to produce MCYSTs (MCYSTs) with concentrations of 1438 and 630 microg g(-1) dry weight, respectively. HPLC analysis of the methanolic extracts of the two species showed that M. tenuissima extract contained MCYST-RR and -LR/demethyl LR plus 3 minor unidentified MCYSTs, while L. boryana extract contained MCYST-YR, -LR/demethyl LR, and 2 minor unidentified MCYSTs. This study suggests that epiphytic species should be considered during monitoring of toxic cyanobacteria in water sources. 2010 Elsevier Ltd. All rights reserved.

  11. Microcystin-LR does not induce alterations to transcriptomic or metabolomic profiles of a model heterotrophic bacterium.

    Directory of Open Access Journals (Sweden)

    Robbie M Martin

    Full Text Available Microcystins are secondary metabolites produced by several freshwater, bloom-forming cyanobacterial species. Microcystin-producing cyanobacteria co-occur with a complex community of heterotrophic bacteria. Though conflicting, studies suggest that microcystins affect the physiology of heterotrophic bacteria by inducing oxidative stress and increasing cell envelope permeability. Based on these observations, we hypothesized that exposure to microcystin should induce differential expression in genes responding to oxidative and envelope stress and trigger shifts in metabolite pools. We tested this hypothesis by exposing Escherichia coli MG1655 to 1 and 10 mg/L microcystin-LR and monitored global changes to gene expression, cellular metabolite pools, and lipid composition using RNA-sequencing and UPLC-MS. Contrary to reported studies, we observed no evidence that microcystin-LR induced oxidative or cell envelope stress in E. coli under the tested conditions. Our results suggest a potential difference in mechanism by which microcystin-LR interacts with heterotrophic bacteria vs. cyanobacteria.

  12. The uptake kinetics and immunotoxic effects of microcystin-LR in human and chicken peripheral blood lymphocytes in vitro

    International Nuclear Information System (INIS)

    Lankoff, Anna; Carmichael, Wayne W.; Grasman, Keith A.; Yuan, Moucun

    2004-01-01

    Microcystin-LR is a cyanobacterial heptapeptide that presents acute and chronic hazards to animal and human health. We investigated the influence of this toxin on human and chicken immune system modulation in vitro. Peripheral blood lymphocytes were treated with microcystin-LR at environmentally relevant doses of 1, 10 and 25 μg/ml for 12, 24, 48, 72 h (for proliferation assay cells were treated for 72 h). T-cell and B-cell proliferation as well as apoptosis and necrosis were determined in human and chicken samples. IL-2 and IL-6 production by human lymphocytes also was measured. In addition, uptake kinetics of microcystin-LR into human and chicken peripheral blood lymphocytes were calculated by Liquid Chromatography (LS) /Mass Spectrometry (MS) analysis. At the highest dose microcystin-LR decreased T-cell proliferation and all doses of microcystin-LR inhibited B-cell proliferation. The frequency of apoptotic and necrotic cells increased in a dose and time-dependent manner. Human lymphocytes responded to stimulation with microcystin-LR by increased production of IL-6 and decreased production of IL-2. Human lymphocytes were able to uptake from 0.014 to 1.663 μg/ml and chicken lymphocytes from 0.035 to 1.733 μg/ml of the microcystin-LR added to the cultures, depending on the treatment time and dose. In conclusion, microcystin-LR acted as an immunomodulator in cytokine production and down-regulated lymphocyte functions by induction of apoptosis and necrosis. However, further studies dealing with the influence of microcystin-LR on expression cytokine genes and transcription factors are necessary to confirm these hypotheses

  13. Target gene approaches: Gene expression in Daphnia magna exposed to predator-borne kairomones or to microcystin-producing and microcystin-free Microcystis aeruginosa

    Directory of Open Access Journals (Sweden)

    Courts Cornelius

    2009-11-01

    Full Text Available Abstract Background Two major biological stressors of freshwater zooplankton of the genus Daphnia are predation and fluctuations in food quality. Here we use kairomones released from a planktivorous fish (Leucaspius delineatus and from an invertebrate predator (larvae of Chaoborus flavicans to simulate predation pressure; a microcystin-producing culture of the cyanobacterium Microcystis aeruginosa and a microcystin-deficient mutant are used to investigate effects of low food quality. Real-time quantitative polymerase chain reaction (QPCR allows quantification of the impact of biotic stressors on differential gene activity. The draft genome sequence for Daphnia pulex facilitates the use of candidate genes by precisely identifying orthologs to functionally characterized genes in other model species. This information is obtained by constructing phylogenetic trees of candidate genes with the knowledge that the Daphnia genome is composed of many expanded gene families. Results We evaluated seven candidate reference genes for QPCR in Daphnia magna after exposure to kairomones. As a robust approach, a combination normalisation factor (NF was calculated based on the geometric mean of three of these seven reference genes: glyceraldehyde-3-phosphate dehydrogenase, TATA-box binding protein and succinate dehydrogenase. Using this NF, expression of the target genes actin and alpha-tubulin were revealed to be unchanged in the presence of the tested kairomones. The presence of fish kairomone up-regulated one gene (cyclophilin involved in the folding of proteins, whereas Chaoborus kairomone down-regulated the same gene. We evaluated the same set of candidate reference genes for QPCR in Daphnia magna after exposure to a microcystin-producing and a microcystin-free strain of the cyanobacterium Microcystis aeruginosa. The NF was calculated based on the reference genes 18S ribosomal RNA, alpha-tubulin and TATA-box binding protein. We found glyceraldehyde-3

  14. Effects of coronatine elicitation on growth and metabolic profiles of Lemna paucicostata culture.

    Directory of Open Access Journals (Sweden)

    Jin-Young Kim

    Full Text Available In this study, the effects of coronatine treatment on the growth, comprehensive metabolic profiles, and productivity of bioactive compounds, including phenolics and phytosterols, in whole plant cultures of Lemna paucicostata were investigated using gas chromatography-mass spectrometry (GC-MS coupled with multivariate statistical analysis. To determine the optimal timing of coronatine elicitation, coronatine was added on days 0, 23, and 28 after inoculation. The total growth of L. paucicostata was not significantly different between the coronatine treated groups and the control. The coronatine treatment in L. paucicostata induced increases in the content of hydroxycinnamic acids, such as caffeic acid, isoferulic acid, ρ-coumaric acid, sinapic acid, and phytosterols, such as campesterol and β-sitosterol. The productivity of these useful metabolites was highest when coronatine was added on day 0 and harvested on day 32. These results suggest that coronatine treatment on day 0 activates the phenolic and phytosterol biosynthetic pathways in L. paucicostata to a greater extent than in the control. To the best of our knowledge, this is the first report to investigate the effects of coronatine on the alteration of metabolism in L. paucicostata based on GC-MS profiling. The results of this research provide a foundation for designing strategies for enhanced production of useful metabolites for pharmaceutical and nutraceutical industries by cultivation of L. paucicostata.

  15. Differential oxidative and antioxidative response of duckweed Lemna minor toward plant growth promoting/inhibiting bacteria.

    Science.gov (United States)

    Ishizawa, Hidehiro; Kuroda, Masashi; Morikawa, Masaaki; Ike, Michihiko

    2017-09-01

    Bacteria colonizing the plant rhizosphere are believed to positively or negatively affect the host plant productivity. This feature has inspired researchers to engineer such interactions to enhance crop production. However, it remains to be elucidated whether rhizobacteria influences plant oxidative stress vis-a-vis other environmental stressors, and whether such influence is associated with their growth promoting/inhibiting ability. In this study, two plant growth-promoting bacteria (PGPB) and two plant growth-inhibiting bacteria (PGIB) were separately inoculated into axenic duckweed (Lemna minor) culture under laboratory conditions for 4 and 8 days in order to investigate their effects on plant oxidative stress and antioxidant activities. As previously characterized, the inoculation of PGPB and PGIB strains accelerated and reduced the growth of L. minor, respectively. After 4 and 8 days of cultivation, compared to the PGPB strains, the PGIB strains induced larger amounts of O 2 •- , H 2 O 2 , and malondialdehyde (MDA) in duckweed, although all bacterial strains consistently increased O 2 •- content by two times more than that in the aseptic control plants. Activities of five antioxidant enzymes were also elevated by the inoculation of PGIB, confirming the severe oxidative stress condition in plants. These results suggest that the surface attached bacteria affect differently on host oxidative stress and its response, which degree correlates negatively to their effects on plant growth. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  16. Possible ecological risk of two pharmaceuticals diclofenac and paracetamol demonstrated on a model plant Lemna minor.

    Science.gov (United States)

    Kummerová, Marie; Zezulka, Štěpán; Babula, Petr; Tříska, Jan

    2016-01-25

    Lemna minor is often used in environmental risk assessment and it can be supposed that usually evaluated parameters will be reliable even for assessing the risk of pharmaceuticals. Subtle changes in duckweed plant number, biomass production, and leaf area size induced by 10-day-exposure to diclofenac (DCF) and paracetamol (PCT) (0.1, 10, and 100 μg/L), excepting 100 μg/L DCF, are in contrast with considerable changes on biochemical and histochemical level. Both drugs caused a decrease in content of photosynthetic pigments (by up to 50%), an increase in non-photochemical quenching (by 65%) and decrease in relative chlorophyll fluorescence decay values (by up to 90% with DCF). Both DCF and especially PCT increased amount of reactive nitrogen and oxygen species in roots. DCF-induced effects included mainly increased lipid peroxidation (by 78%), disturbation in membrane integrity and lowering both oxidoreductase and dehydrogenase activities (by 30%). PCT increased the content of soluble proteins and phenolics. Higher concentrations of both DCF and PCT increased the levels of oxidised ascorbate (by 30%) and oxidised thiols (by up to 84% with DCF). Glutathion-reductase activity was elevated by both pharmaceuticals (nearly by 90%), glutathion-S-transferase activity increased mainly with PCT (by 22%). The early and sensitive indicators of DCF and PCT phytotoxicity stress in duckweed are mainly the changes in biochemical processes, connected with activation of defense mechanisms against oxidative stress. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Capacidad de las macrofitas Lemna minor y Eichhornia crassipes para eliminar el niquel

    Directory of Open Access Journals (Sweden)

    BRES, P

    2012-04-01

    Full Text Available El objetivo de este trabajo fue estudiar la capacidad de dos especies de macrofitas, Lemna minor y Eichhornia crassipes, para eliminar el níquel. Se realizaron cuatro tratamientos durante dos semanas para cada una de las especies. Las plantas fueron incubadas con 0, 1, 3 y 6 mg l-1 de Ni. Ambas especies mostraron, en todos los tratamientos con Ni, una reducción en la concentración a lo largo del tiempo. L. minor mostró ser más eficiente para remover este ión a la más baja concentración. Sin embargo, en concentraciones más elevadas no se observaron diferencias entre ambas especies. El análisis del tejido de las plantas mostró que las mismas acumulaban el metal, en los tres casos evaluados con concentraciones diferentes.Palabras clave: fitorremediación, metales pesados, plantas acuáticas, acumulación.

  18. Diferenciación molecular de Lemna aequinoctialis y L. Valdiviana (lemnaceae por patrones proteicos

    Directory of Open Access Journals (Sweden)

    Mª del Milagro Montero Rojas

    2016-03-01

    Full Text Available El estudio se llevó a cabo en el Laboratorio de Genética Molecular de la Universidad Nacional, Heredia, Costa Rica. Se utilizaron plantas acuáticas macrófitas de Lemna valdiviana y L. aequinoctialis previamente identificadas. Estas especies habitan en aguas ricas en sales disueltas y aguas servidas. Recientemente se les consideró como un indicador de la contaminación ocasionada por pesticidas y herbicidas en el agua. La composición proteica llega a niveles entre 38 y 43% de materia seca, importante para diversos usos. La extracción de proteínas totales, por medio de electroforesis discontinua en gel de poliacrilamida, se realizó en condiciones reductoras con SDS (SDS-PAGE. Los geles separadores empleados fueron al 8 y 10%, gel espaciador al 4% y la tinción se efectuó con azul commassie. Los diversos patrones proteicos reflejaron diferencias genéticas entre ambas especies que se pueden deber a las diferencias de hábitat y de reproducción.

  19. Uptake of Cadmium by Lemna minor, a (hyper?- accumulator plant involved in phytoremediation applications

    Directory of Open Access Journals (Sweden)

    Bianconi D.

    2013-04-01

    Full Text Available Metal pollution in waters and soils is a major environmental and human health problem. Cadmium (Cd2+ is a heavy metal displaying toxic effects in plants. In this work we studied the potentiality of Lemna minor, a monocotyledonous aquatic macrophyte, to phytoremediate cadmium-polluted waters. The plants were exposed to different cadmium concentrations 0, 13, 22 and 46μM CdSO4 for a period of 24, 48 and 72 hours. Relative growth rates (RGR, bioconcentration factor (BCF, tolerance index (Ti, cadmium uptake in whole plant and maximum efficiency of PSII (Fv/Fm were measured under controlled climate conditions. RGR, Ti and Fv/Fm declined with increasing exposure time and cadmium concentrations, while the BCF and cadmium uptake showed an opposite behavior. Data analysis of RGR, BCF, Tiand FV/FM indicates that L. minor maintains a good capacity of growth, metal bioconcentration, tolerance and efficiency of PSII up to 48h in plants exposed to 13 and 22μM CdSO4. Our results exhibited that L. minor is a good cadmium accumulator and is able to remediate Cd-polluted waters, especially at low Cd concentrations.

  20. Catalytic production of levulinic acid and ethyl levulinate from uniconazole-induced duckweed (Lemna minor).

    Science.gov (United States)

    Liu, Chunguang; Feng, Qingna; Yang, Jirui; Qi, Xinhua

    2018-05-01

    Duckweed (Lemna minor) with a high starch content of 50.4% was cultivated by uniconazole-induction method. The cultivated duckweed was used to produce value-added chemicals such as glucose, levulinic acid and formic acid in diluted HCl aqueous solution. A high glucose yield of 93.4% (471 g/kg based on loading duckweed mass) could be achieved at 180 °C in short reaction time, and the generated glucose was converted into levulinic acid and formic acid with yields of 52.0% and 34.1%, respectively, for 150 min, corresponding to 262 g/kg levulinic acid yield and 171 g/kg formic acid yield based on the mass of loading duckweed, respectively. Moreover, the duckweed was efficiently converted to ethyl levulinate with 55.2% yield (400.6 g/kg) at 200 °C in ethanol. This work provides a promising strategy for the production of value-added chemicals from phytoplankton that is able to purify the wastewater containing high content of P and N. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Thorough removal of inorganic and organic mercury from aqueous solutions by adsorption on Lemna minor powder

    International Nuclear Information System (INIS)

    Li Shunxing; Zheng Fengying; Huang Yang; Ni Jiancong

    2011-01-01

    The adsorption ability of duckweed (Lemna minor) powders for removing inorganic and organic mercury (methyl and ethyl mercury) has been studied using cold vapour atomic absorption spectrometry. The optimal adsorption conditions were: (a) the pH value of the solution 7.0 for inorganic and ethyl mercury, 9.0 for methyl mercury, and (b) equilibrium adsorption time 10, 20, and 40 min for inorganic mercury, methyl mercury, and ethyl mercury, respectively. After adsorption by L. minor powder for 40 min, when the initial concentrations of inorganic and organic mercury were under 12.0 μg L -1 and 50.0 μg L -1 , respectively, the residual concentrations of mercury could meet the criterion of drinking water (1.0 μg L -1 ) and the permitted discharge limit of wastewater (10.0 μg L -1 ) set by China and USEPA, respectively. Thorough removal of both inorganic and organic mercury from aqueous solutions was reported for the first time. The significant adsorption sites were C-O-P and phosphate groups by the surface electrostatic interactions with aqueous inorganic and organic mercury cations, and then the selective adsorption was resulted from the strong chelating interaction between amine groups and mercury on the surface of L. minor cells.

  2. Effects of microcystin-producing and microcystin-freeMicrocystis aeruginosa on enzyme activity and nutrient content in the rotifer Brachionus calyciflorus.

    Science.gov (United States)

    Liang, Ye; Su, Yuqi; Ouyang, Kai; Chen, Xinglan; Yang, Jiaxin

    2017-04-01

    Toxic cyanobacterial blooms disrupt freshwater recreation and adversely affect zooplankton. The freshwater cyanobacterium Microcystis aeruginosa produces microcystins, which are compounds toxic to rotifers. This study evaluated the effects of M. aeruginosa on enzyme activity and nutrient content in the rotifer Brachionus calyciflorus Pallas. The rotifers were fed on Chlorella pyrenoidosa, Scenedesmus obliquus, microcystin-producing and microcystin-free M. aeruginosa alone, and mixtures of green algae combined with toxic and nontoxic cyanobacteria, respectively. Activities of amylase, pepsase, trypsin, cellulase, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were assessed after rotifer exposure to an environmental stressor. Nutrients analyzed were glycogen, protein, and triglyceride (TG). Single cyanobacteria and mixtures combined with toxic M. aeruginosa inhibited SOD activity. CAT and GPx activities significantly increased in rotifers fed with the mixture of Chlorella and toxic cyanobacteria. The activity of digestive enzymes increased compared with the Chlorella group in single and mixed diets. Glycogen and protein decreased in Microcystis mixtures, whereas TG content increased. The grazing rate (G) of the rotifers decreased with grazing time. High G value was observed with green algae in every treatment group. Although the toxins released after grazing on Microcystis affected rotifer enzyme activity and nutrient content, B. calyciflorus changed its physiological performance and grazing intensity with food type in response to eutrophic conditions.

  3. Degradation of natural toxins by phthalocyanines-example of cyanobacterial toxin, microcystin

    Czech Academy of Sciences Publication Activity Database

    Jančula, D.; Blahová, L.; Karásková, M.; Maršálek, Blahoslav

    2010-01-01

    Roč. 62, č. 2 (2010), s. 273-278 ISSN 0273-1223 R&D Projects: GA MŠk 1M0571 Institutional research plan: CEZ:AV0Z60050516 Keywords : microcystin * phthalocyanine * singled oxygen Subject RIV: EF - Botanics Impact factor: 1.056, year: 2010

  4. Cyanobacteria and microcystin contamination in untreated and treated drinking water in Ghana

    Czech Academy of Sciences Publication Activity Database

    Addico, G.N.D.; Hardege, J. D.; Kohoutek, J.; Degraft-Johnson, K. A. A.; Babica, Pavel

    2017-01-01

    Roč. 8, č. 1 (2017), s. 92-106 ISSN 1947-573X Institutional support: RVO:67985939 Keywords : Ghana * microcystin * drinking water treatment Subject RIV: DJ - Water Pollution ; Quality OBOR OECD: Environmental sciences (social aspects to be 5.7)

  5. Optimization of an effective extraction procedure for the analysis of microcystins in soils and lake sediments

    Energy Technology Data Exchange (ETDEWEB)

    Chen Wei [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Li Lin [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China); Gan Nanqin [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China); Song Lirong [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China)]. E-mail: lrsong@ihb.ac.cn

    2006-09-15

    Microcystin analysis in sediments and soils is considered very difficult due to low recovery for extraction. This is the primary limiting factor for understanding the fate of toxins in the interface between water and sediment in both the aquatic ecosystem as well as in soils. In the present study, a wide range of extraction solvents were evaluated over a wide range of pH, extraction approaches and equilibration time to optimize an effective extraction procedure for the analysis of microcystins in soils and lake sediments. The number of extractions required and acids in extraction solutions were also studied. In this procedure, EDTA-sodium pyrophosphate solution was selected as an extraction solvent based on the adsorption mechanism study. The optimized procedure proved to be highly efficient and achieved over 90% recovery. Finally, the developed procedure was applied to field soil and sediment sample collected from Chinese lakes during bloom seasons and microcystins were determined in six of ten samples. - Efficiency of extraction of microcystins from soil and sediment was greatly increased.

  6. Toxicological Review of Cyanobacterial Toxins: Microcystins Lr, Rr, Yr and La (External Review Draft)

    Science.gov (United States)

    The National Center for Environmental Assessment has prepared the Toxicological Reviews of Cyanobacterial Toxins: Anatoxin-a, Cylindrospermopsin and Microcystins (LR, RR, YR and LA) as a series of dose-response assessments to support the health assessment of unregulated contamina...

  7. A survey for the presence of microcystins in aquaculture ponds in ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-16

    Nov 16, 2009 ... Brazil. Accepted 2 October, 2009. Aquaculture ponds in Zaria, Nigeria, were screened for the occurrence of the hepatotoxic microcystins using an ELISA method. Four genera of .... A few ponds were enriched with fertilizers to enhance primary ... cific markets for human consumption. These ponds were ...

  8. Microcystin production and regulation under nutrient stress conditions in toxic microcystis strains.

    Science.gov (United States)

    Pimentel, Juliana S M; Giani, Alessandra

    2014-09-01

    Microcystin is a common and well-known cyanobacterial toxin whose intracellular role is still under investigation. Increasing knowledge on microcystin gene expression and regulation can contribute to the understanding of its putative cellular function. In this work, reverse transcription-quantitative PCR (RT-qPCR) was used to investigate the transcriptional response of the mcyD gene to nitrogen (nitrate and ammonium) and phosphorus limitation in two toxic Microcystis strains. The existence of a direct correlation between transcripts of mcyD and ntcA genes was also identified. In previous studies, NtcA (global nitrogen regulator) has been described as a potential component in the control of microcystin biosynthesis. This research showed that stress agents linked to nutrient deprivation could lead to a significant increase of microcystin production in both strains studied. The more toxic strain proved to be more resistant to nutrient limitation. The similar outcomes of mcyD regulation observed for all nutrients suggest that this response can be linked to oxidative stress of cells undergoing adverse growth conditions. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  9. Occurrence of Microcystis aeruginosa and microcystins in Río de la Plata river (Argentina

    Directory of Open Access Journals (Sweden)

    Darío Andrinolo

    2007-07-01

    Full Text Available This paper is the first report on microcystins producer blooms of Microcystis aeruginosa in the Argentinean coast of the Río de la Plata river, the most important drinking water supply of Argentina. The distribution of toxic cyanobacterium Microcystis cf. aeruginosa blooms in the Argentinean coast of the Rio de la Plata river was studied from December 2003 and January 2006. Microcystis aeruginosa persisted in the river with values ranged between 0 - 7.8 10(4 cells ml-1. Samples of two Microcystis aeruginosa water blooms were collected at La Plata river and were analyzed by the mouse bioassay and by high-performance liquid chromatography with Diode-array and MS detector. The samples showed high hepatotoxicity in mouse bioassay and, in accordance, important amount of microcystins. The bloom samples contained microcystins LR and a variant of microcystin with a molecular ion [M+H]+= 1037.8 m/z as major components. The total toxin content found in these samples was 0.94μg/mg and 0.69μg/mg of lyophilised cells. We conclude that the presence of toxic clones of Microcystis aeruginosa in the Argentinean coast of the Río de la Plata is an actual sanitary and environmental problem and that further studies are necessary to make the risk assessment.

  10. First report of an Anabaena Bory strain containing microcystin-LR in ...

    African Journals Online (AJOL)

    In South Africa, little is known about the production of microcystin by the genus Anabaena Bory. In April 2012, during a cyanobacterial bloom event in Theewaterskloof Dam, Western Cape province, the plankton was sampled on 10 occasions. The dominant algae belonged to the genus Anabaena, a family of filamentous ...

  11. Hepatotoxic microcystin removal using pumice embedded monolithic composite cryogel as an alternative water treatment method.

    Science.gov (United States)

    Gurbuz, Fatma; Ceylan, Şeyda; Odabaşı, Mehmet; Codd, Geoffrey A

    2016-03-01

    Microcystins are the most commonly encountered water-borne cyanotoxins which present short- and long-term risks to human health. Guidelines at international and national level, and legislation in some countries, have been introduced for the effective health risk management of these potent hepatotoxic, tumour-promoters. The stable cyclic structure of microcystins and their common production by cyanobacteria in waterbodies at times of high total dissolved organic carbon content presents challenges to drinking water treatment facilities, with conventional, advanced and novel strategies under evaluation. Here, we have studied the removal of microcystins using three different forms of pumice particles (PPs), which are embedded into macroporous cryogel columns. Macroporous composite cryogel columns (MCCs) are a new generation of separation media designed to face this challenging task. Three different MCCs were prepared by adding plain PPs, Cu(2+)-attached PPs and Fe(3+)-attached PPs to reaction media before the cryogelation step. Column studies showed that MCCs could be successfully used as an alternative water treatment method for successful microcystin removal. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Treatment of Cyanobacterial (Microcystin Toxicosis Using Oral Cholestyramine: Case Report of a Dog from Montana

    Directory of Open Access Journals (Sweden)

    Michael J. Murray

    2013-05-01

    Full Text Available A two and a half year old spayed female Miniature Australian Shepherd presented to a Montana veterinary clinic with acute onset of anorexia, vomiting and depression. Two days prior, the dog was exposed to an algal bloom in a community lake. Within h, the animal became lethargic and anorexic, and progressed to severe depression and vomiting. A complete blood count and serum chemistry panel suggested acute hepatitis, and a severe coagulopathy was noted clinically. Feces from the affected dog were positive for the cyanobacterial biotoxin, microcystin-LA (217 ppb. The dog was hospitalized for eight days. Supportive therapy consisted of fluids, mucosal protectants, vitamins, antibiotics, and nutritional supplements. On day five of hospitalization, a bile acid sequestrant, cholestyramine, was administered orally. Rapid clinical improvement was noted within 48 h of initiating oral cholestyramine therapy. At 17 days post-exposure the dog was clinically normal, and remained clinically normal at re-check, one year post-exposure. To our knowledge, this is the first report of successful treatment of canine cyanobacterial (microcystin toxicosis. Untreated microcystin intoxication is commonly fatal, and can result in significant liver damage in surviving animals. The clinical success of this case suggests that oral administration of cholestyramine, in combination with supportive therapy, could significantly reduce hospitalization time, cost-of-care and mortality for microcystin-poisoned animals

  13. Bioaccumulation of microcystins in invasive bivalves: A case study from the boreal lagoon ecosystem

    Directory of Open Access Journals (Sweden)

    Aistė Paldavičienė

    2015-01-01

    Full Text Available In the current study we present the first report on the bioaccumulation of microcystins (MC in zebra mussel Dreissena polymorpha from the eutrophic brackish water Curonian Lagoon. The bioaccumulation capacity was related to age structure of mussels and ambient environmental conditions. We also discuss the relevant implications of these findings for biomonitoring of toxic cyanobacteria blooms in the Curonian Lagoon and potential consequences for D. polymorpha cultivation activities considered for the futures as remediation measure. Samples for the analysis were collected twice per year, in June and September, in 2006, 2007 and 2008, from two sites within the littoral zone of the lagoon. The highest microcystin concentrations were measured in mussels larger than 30 mm length and sampled in 2006 (when a severe toxic cyanobacteria bloom occurred. In the following years, a consistent reduction in bioaccumulated MC concentration was noticed. However, certain amount of microcystin was recorded in mussel tissues in 2007 and 2008, when no cyanotoxins were reported in the phytoplankton. Considering high depuration rates and presence of cyanotoxins in the bottom sediments well after the recorded toxic blooms, we assume mechanism of secondary contamination when microcystin residuals could be uptaken by mussels with resuspended sediment particles.

  14. Mechanism and application of solid phase adsorption toxin tracking for monitoring microcystins.

    Science.gov (United States)

    Zhao, Hui; Qiu, Jiangbing; Fan, Hua; Li, Aifeng

    2013-07-26

    The production of toxic microcystins by cyanobacteria is an important safety issue in terms of ecological food chains and drinking water supplies. Studies were carried out to demonstrate the applicability of solid phase adsorption toxin tracking (SPATT) to the monitoring of microcystins in fresh water. Work focused on the distribution of the intra- and extra-cellular toxins MC-LR and [Dha(7)] MC-LR produced by Microcystis aeruginosa (FACHB 905). The dynamic adsorption and desorption behavior of both toxins on aromatic resins HP20 and SP700 was examined, and the use of SPATT bags for monitoring microcystins in cyanobacterial cultures is discussed. It was shown that intracellular MC-LR and [Dha(7)] MC-LR are released continuously during batch incubation. The adsorption capacity of the SP700 resin was higher than that of the HP20 resin, while the opposite was true for desorption efficiency. The highest desorption efficiency of HP20 was 91.5±4.6% and 89.0±7.1% for MC-LR and [Dha(7)] MC-LR, respectively; accordingly, that of SP700 was 78.1±4.1% and 72.3±2.1%, respectively. Taking both adsorption and desorption behavior into consideration, HP20 is recommended as an adsorbent for SPATT monitoring of microcystins in freshwater bodies. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Eutrophication and Warming Boost Cyanobacterial Biomass and Microcystins

    Directory of Open Access Journals (Sweden)

    Miquel Lürling

    2017-02-01

    Full Text Available Eutrophication and warming are key drivers of cyanobacterial blooms, but their combined effects on microcystin (MC concentrations are less studied. We tested the hypothesis that warming promotes cyanobacterial abundance in a natural plankton community and that eutrophication enhances cyanobacterial biomass and MC concentrations. We incubated natural seston from a eutrophic pond under normal, high, and extreme temperatures (i.e., 20, 25, and 30 °C with and without additional nutrients added (eutrophication mimicking a pulse as could be expected from projected summer storms under climate change. Eutrophication increased algal- and cyanobacterial biomass by 26 and 8 times, respectively, and led to 24 times higher MC concentrations. This effect was augmented with higher temperatures leading to 45 times higher MC concentrations at 25 °C, with 11 times more cyanobacterial chlorophyll-a and 25 times more eukaryote algal chlorophyll-a. At 30 °C, MC concentrations were 42 times higher, with cyanobacterial chlorophyll-a being 17 times and eukaryote algal chlorophyll-a being 24 times higher. In contrast, warming alone did not yield more cyanobacteria or MCs, because the in situ community had already depleted the available nutrient pool. MC per potential MC producing cell declined at higher temperatures under nutrient enrichments, which was confirmed by a controlled experiment with two laboratory strains of Microcystis aeruginosa. Nevertheless, MC concentrations were much higher at the increased temperature and nutrient treatment than under warming alone due to strongly promoted biomass, lifting N-imitation and promotion of potential MC producers like Microcystis. This study exemplifies the vulnerability of eutrophic urban waters to predicted future summer climate change effects that might aggravate cyanobacterial nuisance.

  16. Molecular Mechanisms of Microcystin Toxicity in Animal Cells

    Directory of Open Access Journals (Sweden)

    Alexandre Campos

    2010-01-01

    Full Text Available Microcystins (MC are potent hepatotoxins produced by the cyanobacteria of the genera Planktothrix, Microcystis, Aphanizomenon, Nostoc and Anabaena. These cyclic heptapeptides have strong affinity to serine/threonine protein phosphatases (PPs thereby acting as an inhibitor of this group of enzymes. Through this interaction a cascade of events responsible for the MC cytotoxic and genotoxic effects in animal cells may take place. Moreover MC induces oxidative stress in animal cells and together with the inhibition of PPs, this pathway is considered to be one of the main mechanisms of MC toxicity. In recent years new insights on the key enzymes involved in the signal-transduction and toxicity have been reported demonstrating the complexity of the interaction of these toxins with animal cells. Key proteins involved in MC up-take, biotransformation and excretion have been identified, demonstrating the ability of aquatic animals to metabolize and excrete the toxin. MC have shown to interact with the mitochondria. The consequences are the dysfunction of the organelle, induction of reactive oxygen species (ROS and cell apoptosis. MC activity leads to the differential expression/activity of transcriptional factors and protein kinases involved in the pathways of cellular differentiation, proliferation and tumor promotion activity. This activity may result from the direct inhibition of the protein phosphatases PP1 and PP2A. This review aims to summarize the increasing data regarding the molecular mechanisms of MC toxicity in animal systems, reporting for direct MC interacting proteins and key enzymes in the process of toxicity biotransformation/excretion of these cyclic peptides.

  17. Apport du traitement d'images dans le suivi de l'influence des teneurs en nutriments sur la croissance des lentilles d'eau (Lemna minor

    Directory of Open Access Journals (Sweden)

    Tangou, TT.

    2014-01-01

    Full Text Available Contribution of image processing in monitoring the influence of nutrients on the growth of duckweed (Lemna minor. The growth of duckweed (Lemna minor is an important component in the treatment process in wastewater floating macrophyte ponds. An excess or shortage of this biomass may be responsible for the dysfunction of such ponds. Modeling these duckweed ponds through mass balances based on Petersen's matrix may be helpful in facilitating the optimal management of such facilities. This study sought to assess the efficiency of digital image processing in the growth monitoring of Lemna minor under different concentrations of nitrogen and phosphorus. The experiments were carried out in a growth chamber (phytotron using an experimental pilot involving initial fresh Lemna minor biomass (1 g, nitrogen and phosphorus concentrations varying between 5 and 64 mg N-NH4+·l-1, and 1 and 24 mg P-PO43-·-1, respectively. Digital image processing was achieved in addition to gravimetric methods (fresh weight and/or dry weight. Our results showed that the image processing method allowed a continuous and non-destructive monitoring of duckweed biomass. The growth of Lemna minor progressively decreased when nitrogen and phosphorus concentrations were greater than 16 mg N-NH4+·l-1 and 6 mg P-PO43-·-1. The maximum growth rates μmax were of the order of 0.07 d-1. The kinetic constants KS and KI were respectively 3.83 mg·l-1 and 204 mg·l-1 for nitrogen, and 1.26 mg·l-1 and 13.3 mg·l-1 for phosphorus. Such results are interesting as they could contribute to the optimal management of Lemna minor and the modeling of biological reactors.

  18. Environmental influence on cyanobacteria abundance and microcystin toxin production in a shallow temperate lake.

    Science.gov (United States)

    Lee, Tammy A; Rollwagen-Bollens, Gretchen; Bollens, Stephen M; Faber-Hammond, Joshua J

    2015-04-01

    The increasing frequency of harmful cyanobacterial blooms in freshwater systems is a commonly recognized problem due to detrimental effects on water quality. Vancouver Lake, a shallow, tidally influenced lake in the flood plain of the Columbia River within the city of Vancouver, WA, USA, has experienced numerous summertime cyanobacterial blooms, dominated by Aphanizomenon sp. and Anabaena sp. Cyanobacteria abundance and toxin (microcystin) levels have been monitored in this popular urban lake for several years; however, no previous studies have identified which cyanobacteria species produce toxins, nor analyzed how changes in environmental variables contribute to the fluctuations in toxic cyanobacteria populations. We used a suite of molecular techniques to analyze water samples from Vancouver Lake over two summer bloom cycles (2009 and 2010). Both intracellular and extracellular microcystin concentrations were measured using an ELISA kit. Intracellular microcystin concentrations exceeded WHO guidelines for recreational waters several times throughout the sampling period. PCR results demonstrated that Microcystis sp. was the sole microcystin-producing cyanobacteria species present in Vancouver Lake, although Microcystis sp. was rarely detected in microscopical counts. qPCR results indicated that the majority of the Microcystis sp. population contained the toxin-producing gene (mcyE), although Microcystis sp. abundance rarely exceeded 1 percent of overall cyanobacteria abundance. Non-metric multidimensional scaling (NMDS) revealed that PO4-P was the main environmental variable influencing the abundance of toxic and non-toxic cyanobacteria, as well as intracellular microcystin concentrations. Our study underscores the importance of using molecular genetic techniques, in addition to traditional microscopy, to assess the importance of less conspicuous species in the dynamics of harmful algal blooms. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Analyses of cyanobacterial toxins (microcystins, cylindrospermopsins) in the reservoirs of the Czech Republic and evaluation of health risks

    Czech Academy of Sciences Publication Activity Database

    Bláhová, Lucie; Babica, Pavel; Adamovský, Ondřej; Kohoutek, Jiří; Maršálek, Blahoslav

    2008-01-01

    Roč. 6, č. 4 (2008), s. 223-227 ISSN 1610-3653 Institutional research plan: CEZ:AV0Z60050516 Keywords : microcystins * cylindrospermopsin * health risks Subject RIV: EF - Botanics Impact factor: 1.366, year: 2008

  20. Characterization of indole acetic acid endophyte producers in ...

    African Journals Online (AJOL)

    Valued Acer Customer

    2015-02-18

    academicjournals.org/AJB. African Journal of Biotechnology. Full Length Research Paper. Characterization of indole acetic acid endophyte producers in authoctonus Lemna gibba plants from. Xochimilco Lake. Orlando Ortega-Acosta.

  1. Micro-scale elemental partition in tissues of the aquatic plant Lemna minor L. exposed to highway drainage water

    Energy Technology Data Exchange (ETDEWEB)

    Mendes Godinho, R., E-mail: rmgodinho@yahoo.com [IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa, EN 10, 2686-953 Sacavém (Portugal); IPMA Instituto Português do Mar e da Atmosfera, Lisboa 1449-006 (Portugal); Raimundo, J.; Vale, C.; Anes, B.; Brito, P. [IPMA Instituto Português do Mar e da Atmosfera, Lisboa 1449-006 (Portugal); Alves, L.C.; Pinheiro, T. [IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa, EN 10, 2686-953 Sacavém (Portugal); CFNUL – Centro de Física Nuclear da Universidade de Lisboa (Portugal)

    2013-07-01

    In the scope of a monitoring program to assess the environmental impact of automobile traffic over one main bridge in Lisbon, both water and duckweed (Lemna minor L.) were sampled from the road drainage tanks and analyzed for chemical elements. Plants uptake Cr, Mn, Cu, and Zn metals from rain water draining the bridge road. Nuclear microprobe elemental maps of cryosections of L. minor tissues showed that incorporated elements were internalized in fronds of the plant. This approach at micrometer level allows a better knowledge of the elemental tissue partitioning in this biomonitor organism.

  2. Toxic Cyanobacteria in Svalbard: Chemical Diversity of Microcystins Detected Using a Liquid Chromatography Mass Spectrometry Precursor Ion Screening Method

    Directory of Open Access Journals (Sweden)

    Julia Kleinteich

    2018-04-01

    Full Text Available Cyanobacteria synthesize a large variety of secondary metabolites including toxins. Microcystins (MCs with hepato- and neurotoxic potential are well studied in bloom-forming planktonic species of temperate and tropical regions. Cyanobacterial biofilms thriving in the polar regions have recently emerged as a rich source for cyanobacterial secondary metabolites including previously undescribed congeners of microcystin. However, detection and detailed identification of these compounds is difficult due to unusual sample matrices and structural congeners produced. We here report a time-efficient liquid chromatography-mass spectrometry (LC-MS precursor ion screening method that facilitates microcystin detection and identification. We applied this method to detect six different MC congeners in 8 out of 26 microbial mat samples of the Svalbard Archipelago in the Arctic. The congeners, of which [Asp3, ADMAdda5, Dhb7] MC-LR was most abundant, were similar to those reported in other polar habitats. Microcystins were also determined using an Adda-specific enzyme-linked immunosorbent assay (Adda-ELISA. Nostoc sp. was identified as a putative toxin producer using molecular methods that targeted 16S rRNA genes and genes involved in microcystin production. The mcy genes detected showed highest similarities to other Arctic or Antarctic sequences. The LC-MS precursor ion screening method could be useful for microcystin detection in unusual matrices such as benthic biofilms or lichen.

  3. Modeling the interaction of light intensity, nutrient concentration and uranium toxicity in Lemna minor

    Energy Technology Data Exchange (ETDEWEB)

    Zimmer, E.; Horemans, N.; Vandenhove, H. [Belgian Nuclear Research Centre SCK-CEN (Belgium); Cedergreen, N. [University of Copenhagen (Denmark); Jager, T. [Vrije Universiteit Amsterdam (Netherlands)

    2014-07-01

    Radioecology aims at assessing the effect of radionuclides and radiation on the environment. Since we cannot test every possible environmental situation in the laboratory, we need modeling approaches to extrapolate the results of toxicity assays to environmentally relevant scenarios. Therefore, it is of crucial importance to understand the effect of relevant environmental factors, such as nutrients, temperature and light on the toxicity of the test. Radionuclides are often found to induce the production of reactive oxygen species (ROS). In plants, an overload of ROS can lead to disturbances of the photosynthetic system. Since the light intensity determines the efficiency of the photo-systems in plants, it can be expected to interact with the effect of radionuclides. The nutrient concentration of the test medium determines the physiological state of the plant, affecting in turn the plant's capability of dealing with stress and hence influences the toxicity of the contaminant. To study the interaction of stressors with environmental conditions, mechanistic effect modeling is promoted widely in ecotoxicology. In principle, the modelling aims at a mechanistic understanding of the different processes causing the stress individually, and integrating them in one framework to study their joint effect and possible interaction. We here present a mechanistic effect model for Lemna minor (common duckweed), which is based on Dynamic Energy Budget (DEB) theory. Models based on DEB have been used widely to study the effects of compounds on animals. Due to its general applicability to all types of organisms, it holds potential to be used for comparison of species and compounds in a broad context. Energy uptake from the environment is modeled explicitly, and metabolic rates are set to depend on temperature in DEB models. Therefore, they can be used to extrapolate effects to a wide range of environmentally relevant scenarios. Until now, the DEB research in ecotoxicology has

  4. Duckweed (Lemna minor as a model plant system for the study of human microbial pathogenesis.

    Directory of Open Access Journals (Sweden)

    Yong Zhang

    Full Text Available BACKGROUND: Plant infection models provide certain advantages over animal models in the study of pathogenesis. However, current plant models face some limitations, e.g., plant and pathogen cannot co-culture in a contained environment. Development of such a plant model is needed to better illustrate host-pathogen interactions. METHODOLOGY/PRINCIPAL FINDINGS: We describe a novel model plant system for the study of human pathogenic bacterial infection on a large scale. This system was initiated by co-cultivation of axenic duckweed (Lemna minor plants with pathogenic bacteria in 24-well polystyrene cell culture plate. Pathogenesis of bacteria to duckweed was demonstrated with Pseudomonas aeruginosa and Staphylococcus aureus as two model pathogens. P. aeruginosa PAO1 caused severe detriment to duckweed as judged from inhibition to frond multiplication and chlorophyll formation. Using a GFP-marked PAO1 strain, we demonstrated that bacteria colonized on both fronds and roots and formed biofilms. Virulence of PAO1 to duckweed was attenuated in its quorum sensing (QS mutants and in recombinant strains overexpressing the QS quenching enzymes. RN4220, a virulent strain of S. aureus, caused severe toxicity to duckweed while an avirulent strain showed little effect. Using this system for antimicrobial chemical selection, green tea polyphenols exhibited inhibitory activity against S. aureus virulence. This system was further confirmed to be effective as a pathogenesis model using a number of pathogenic bacterial species. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that duckweed can be used as a fast, inexpensive and reproducible model plant system for the study of host-pathogen interactions, could serve as an alternative choice for the study of some virulence factors, and could also potentially be used in large-scale screening for the discovery of antimicrobial chemicals.

  5. Listeria weihenstephanensis sp. nov., isolated from the water plant Lemna trisulca taken from a freshwater pond.

    Science.gov (United States)

    Lang Halter, Evi; Neuhaus, Klaus; Scherer, Siegfried

    2013-02-01

    The phylogenetic position and phenotypic characteristics of two non-spore-forming bacilli similar to members of the genus Listeria were studied. The gram-reaction-positive, slightly motile, facultatively anaerobic strains were isolated from the water plant Lemna trisulca sampled from a freshwater pond in Bavaria, Germany. Although no identification was possible employing the API Listeria test (bioMérieux), 16S rRNA sequence analysis confirmed a close phylogenetic similarity to Listeria rocourtiae DSM 22097(T) (99.0 % sequence similarity) and a more distant relationship to other Listeria species (96.0 % to Listeria monocytogenes DSM 20600(T) and 95.0 % similarity to Listeria grayi DSM 20601(T)). DNA-DNA hybridization analysis between the isolates and Listeria rocourtiae DSM 22097(T) yielded a similarity of 22.5 %. Analysis of partial sequences of sigB, prs, recA and HSP60 were studied and compared with those of other members of the genus Listeria and Brochothrix thermosphacta DSM 20171(T) supporting the relationships indicated by 16S rRNA gene sequences. The studied isolates were non-haemolytic and were not associated with cases of human or animal disease. While the results demonstrate that the strains belong to the genus Listeria, phenotypic and genotypic differences from Listeria rocourtiae DSM 22097(T) suggest that the strains represent a novel species for which the name Listeria weihenstephanensis sp. nov. is proposed; the type strain is WS 4560(T) ( = DSM 24698(T) = LMG 26374(T)), with WS 4615 ( = DSM 24699 = LMG 26375) as a second strain of the species.

  6. A simple method for analysing the effects of algae on the growth of Lemna and preventing algal growth in duckweed bioassays

    NARCIS (Netherlands)

    Szabo, S.; Roijackers, R.M.M.; Scheffer, M.

    2003-01-01

    A simple novel method for indoor culture experiments with small floating water plants, such as Lemnaceae, is described. Experiments demonstrate that the method allows for longer lasting culture experiments with Lemna, avoiding algal growth and self-shading of fronds by overcrowding. This is achieved

  7. The influence of barley straw extract addition on the growth of duckweed (Lemna valdiviana Phil. under laboratory conditions

    Directory of Open Access Journals (Sweden)

    Pęczuła W.

    2014-01-01

    Full Text Available Due to its ability to forming dense mats in small waterbodies, duckweeds are often considered as nuisance plants in some freshwaters. Up to now, few techniques had been tested aiming towards managing duckweeds, but all of them had appeared to have some disadvantages. As an attempt to find a new effective management tool, a laboratory experiment assessing the influence of barley straw (BS extract addition – a substance used in algal bloom control, upon the growth of the duckweed Lemna valdiviana, was performed. Reaction on two various concentrations of BS extract were quantified by measurements of changes in duckweed biomass and root length. The results showed that plants which have received the extract increased their biomass slower than that of the control, however only those with the addition of smaller amounts of BS differed significantly from the controls. Furthermore, BS addition stimulated the root growth in both experimental tanks. This implies that the mean roots length was higher, although the statistical differences were insignificant. As possible explanation for the observed changes we suggest that: (1 the growth inhibition of Lemna valvidiana under exposition to BS extract might be induced by an uptake of organic compounds from which some (phenolic substances are (probably toxic; (2 competitive interactions with the microbial communities developed upon the duckweed roots might play a role as well.

  8. ANALISIS PENGARUH VARIASI SUHU dan WAKTU PADA PROSES HIDROLISIS TERHADAP KADAR GLUKOSA DALAM PEMANFAATAN Lemna minor SEBAGAI BIOETANOL

    Directory of Open Access Journals (Sweden)

    Vivi Mayangsari

    2014-10-01

    Full Text Available Energi terbarukan sangatlah diperlukan karena semakin meluasnya krisis energi sehingga memerlukan alternatif selain penggunaan bahan bakar fosil, penggunaan bioethanol merupakan alternatif yang baik karena banyak kelebihanya. Lemna minor merupakan salah satu tumbuhan yang berpotensi sebagai bioethanol, hal ini dapat dilihat dari kandungan glukosanya yang tinggi. Tujuan penelitian ini adalah untuk mengetahui hubungan waktu dan suhu pada proses hidrolisis terhadap nilai kadar glukosa serta mengetahui hubungan densitas terhadap kadar etanol. Proses ekstrasi glukosa menggunakan perbandingan volume HCl dengan kosentrasi 0,1 N, berat serbuk Lemna minor dan volume aquades yaitu 1:10:100 dengan variasi waktu ekstrasi 60, 90, dan 120 menit pada variasi suhu 60, 70, 80 °C dengan ukuran serbuk 60 mesh. Hasil penelitian ekstrasi hidrolisis terbaik pada menit ke-90 didapatkan panjang gelombang tertinggi 415 nm. Semua glukosa pada ekstrasi 90 menit difermentasi menggunakan bakteri Saccharomiches cerevisiae sebanyak 10% dari volume glukosa dengan waktu 144 jam, setelah fermentasi selesai sampel didestilasi untuk menghilangkan kadar air dan dihasilkan kadar ethanol terbaik 0,47% dengan densitas 0,9345 gr/ml3pada panjang gelombang larutan glukosa 316 nm.

  9. ANALISIS PENGARUH VARIASI PERSENTASE RAGI (Saccharomyces cerevisiae DAN WAKTU PADA PROSES FERMENTASI DALAM PEMANFAATAN DUCKWEED (Lemna minor SEBAGAI BIOETANOL

    Directory of Open Access Journals (Sweden)

    Siti Khodijah

    2015-04-01

    Full Text Available Salah satu alternatif dalam mendukung ketersediaan sumber daya energi terbarukan adalah dengan memanfaatkan sumber dari non fosil seperti bioetanol. Bioetanol merupakan etanol yang dibuat dari biomass yang mengandung komponen pati (karbohidrat atau selulosa yang selanjutnya di fermentasi menggunakan bantuan mikroorganisme (Sacharomyces cerevisiae. Karbohidrat yang digunakan pada penelitian ini berasal dari Lemna minor (Duckweed. Penelitian ini bertujuan membuat bioetanol dari Lemna minor dengan variasi penambahan ragi dan lamanya waktu fermentasi terhadap nilai kadar etanol dan nilai densitas, serta mengetahui hubungan densitas dengan kadar etanol. Produksi bioetanol dari tanaman yang mengandung pati (karbohidrat, dilakukan melalui proses konversi karbohidrat menjadi gula (glukosa dengan hidrolisis asam (HCl, hidrolisat yang diperoleh selanjutnya dilakukan fermentasi dengan menambahkan yeast atau ragi sehingga diperoleh bioetanol. Variabel yang digunakan adalah perubahan massa ragi 5%,15%, dan 25% serta lama fermentasi 5, 6, dan 7 hari . Hasil penelitian menunjukkan lama fermentasi dan persentase ragi mempengaruhi kadar etanol. Nilai kadar etanol optimum diperoleh presentase ragi 25% dengan lama fermentasi 7 hari sebesar 3.81% dengan density optimum sebesar 0.9438 gr/cm3, Hubungan nilai densitas berbanding terbalik dengan peningkatan kadar etanol.

  10. Fate, toxicity and bioconcentration of cadmium on Pseudokirchneriella subcapitata and Lemna minor in mid-term single tests.

    Science.gov (United States)

    Clément, Bernard; Lamonica, Dominique

    2018-03-01

    In the frame of a project which consists in modeling a laboratory microcosm under cadmium pressure, we initiated this study on the fate and effects of cadmium in the presence of either the microalga Pseudokirchneriella subcapitata or the duckweed Lemna minor, two organisms of the microcosm. For each organism, growth inhibition tests on a duration of 2-3 weeks were carried out with the objective of linking effects with total dissolved, ionic and internalized forms of cadmium. Numbers of organisms (algal cells or duckweed fronds) in 2-L beakers filled with synthetic nutritive medium containing EDTA were counted during the course of assays, while cadmium concentrations in the water and in the organisms were measured. Free cadmium fraction was calculated using PHREEQC, a computer program for chemical speciation. Results showed that cadmium toxicity to microalgae could be correlated to the free divalent fraction of this metal, limited by the presence of EDTA, and to its concentration in the organisms. Bioconcentration factors for our medium were suggested for P. subcapitata (111,000 on the basis of free cadmium concentration) and L. minor (17,812 on the basis of total dissolved concentration). No effect concentrations were roughly estimated around 400 µg/g for Pseudokirchneriella subcapitata and 200-300 µg/g for Lemna minor. This study is a first step towards a fate model based on chemical speciation for a better understanding of microcosm results.

  11. A Cross-Sectional Investigation of Chronic Exposure to Microcystin in Relationship to Childhood Liver Damage in the Three Gorges Reservoir Region, China

    Science.gov (United States)

    Li, Yan; Chen, Ji-an; Zhao, Qing; Pu, Chaowen; Qiu, Zhiqun; Zhang, Renping

    2011-01-01

    Background: Microcystin-producing Microcystis bloom is a severe water problem in the world. Some reports indicate that chronic exposure to microcystin may result in liver damage in adults, but information on effects in children is limited. Objective: We investigated the relationship between microcystin exposure and liver damage in children. Methods: We measured microcystin concentrations in drinking water and aquatic food (carp and duck) from two lakes and four wells. Participants were 1,322 children 7–15 years of age who obtained drinking water from one of the tested sources, completed questionnaires, and provided blood samples for serum liver enzymes [alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and γ-glutamyltransferase (GGT)] and serum microcystin analysis. Multivariable logistic regression was used to identify risk factors associated with liver damage (two or more abnormal serum enzyme levels in ALT, AST, ALP, or GGT). Results: Microcystin was detected in most samples of water and aquatic food from two lakes. Children who drank water from the lake with the highest microcystin concentrations had a total estimated daily microcystin intake of 2.03 μg, a value much higher than the tolerable daily intake (0.40 μg) proposed by the World Health Organization for children. Hepatitis B virus (HBV) infection, use of hepatotoxic medicines, and microcystin exposure were associated with liver damage. AST and ALP levels were significantly higher in high-microcystin-exposed children than in low-exposed children and unexposed children when participants who were HBV-positive or hepatotoxic medicine users were excluded from the analysis. Conclusion: These results suggest that chronic exposure to microcystin may be associated with liver damage in children in the Three Gorges Reservoir Region. PMID:21561830

  12. Losses of the cyanobacterial toxin microcystin-LR from aqueous solution by adsorption during laboratory manipulations.

    Science.gov (United States)

    Hyenstrand, P; Metcalf, J S; Beattie, K A; Codd, G A

    2001-04-01

    The effect of plastic and methanol on the loss of microcystin-LR from solution was analysed by HPLC with photodiode array detection (HPLC-PDA). With plastic disposable pipette tips, the loss from an aqueous microcystin-LR (MC-LR) solution was 4.2% per tip operation. Using the same pipette tip, four operations were required to completely saturate a single tip with toxin. MC-LR attached to plastic pipette tips could subsequently be eluted by methanol and detected by HPLC-PDA. At methanol concentrations below 25% (v/v), recovered concentrations of MC-LR decreased significantly. Differences in MC-LR concentration were also noted by performing 50% dilution with Milli-Q water or methanol. The results are discussed in relation to the hydrophobicity of MC-LR, analytical procedures and the avoidance of toxin losses from solution during laboratory manipulations.

  13. Destruction of microcystins by conventional and advanced oxidation processes: A review

    DEFF Research Database (Denmark)

    Sharma, Virender K.; Triantis, Theodoros M.; Antoniou, Maria G.

    2012-01-01

    Cyanobacteria blooms pose an environmental hazard because of the release of water soluble toxic compounds, called cyanotoxins. Microcystins (MCs), hepatotoxic cyclic peptide toxins, are the most widespread cyanotoxins with microcystin-LR (MC-LR) the most common and toxic variant. Health effects...... and further processing is required. On the other hand, chemical oxidation processes are a promising alternative treatment option due to the potential of complete destruction of the MCs, transformation to less toxic by-products, and even complete mineralization. MCs reactivity towards different conventional...... treatment facilities. In this review, recent literature concerning treatment of MCs in water by conventional and advanced oxidation processes are reviewed and discussed in terms of the degree of degradation, reaction kinetics, identity and toxicity of oxidation by-products and possible degradation pathways....

  14. The dynamics of toxic microcystis strains and microcystin production in two hypertrofic South African reservoirs

    OpenAIRE

    Barnard, Sandra; Conradie, Karin Ronel

    2012-01-01

    The South African impoundments of Hartbeespoort and Roodeplaat experience excessive blooms of Microcystis species each year. Microcystins, produced primarily by strains of cyanobacteria belonging to the genera Microcystis, Anabaena and Planktothrix, are harmful cyanobacterial hepatotoxins. These bloom-forming cyanobacteria form toxic and non-toxic strains that co-occur and are visually indistinguishable, but can be identified and quantified molecularly. We described the relationships between ...

  15. Analysis of Microcystins in Cyanobacterial Blooms from Freshwater Bodies in England

    Directory of Open Access Journals (Sweden)

    Andrew D. Turner

    2018-01-01

    Full Text Available Cyanobacterial blooms in freshwater bodies in England are currently monitored reactively, with samples containing more than 20,000 cells/mL of potentially toxin-producing species by light microscopy resulting in action by the water body owner. Whilst significantly reducing the risk of microcystin exposure, there is little data describing the levels of these toxins present in cyanobacterial blooms. This study focused on the quantitative LC-MS/MS analysis of microcystins in freshwater samples, collected across England during 2016 and found to contain potentially toxin-producing cyanobacteria. More than 50% of samples contained quantifiable concentrations of microcystins, with approximately 13% exceeding the WHO medium health threshold of 20 μg/L. Toxic samples were confirmed over a nine-month period, with a clear increase in toxins during late summer, but with no apparent geographical patterns. No statistical relationships were found between total toxin concentrations and environmental parameters. Complex toxin profiles were determined and profile clusters were unrelated to cyanobacterial species, although a dominance of MC-RR was determined in water samples from sites associated with lower rainfall. 100% of samples with toxins above the 20 μg/L limit contained cell densities above 20,000 cells/mL or cyanobacterial scum, showing the current regime is suitable for public health. Conversely, with only 18% of cell density threshold samples having total microcystins above 20 μg/L, there is the potential for reactive water closures to unnecessarily impact upon the socio-economics of the local population. In the future, routine analysis of bloom samples by LC-MS/MS would provide a beneficial confirmatory approach to the current microscopic assessment, aiding both public health and the needs of water users and industry.

  16. An SPR biosensor for the detection of microcystins in drinking water

    Czech Academy of Sciences Publication Activity Database

    Herranz, S.; Bocková, Markéta; Marazuela, M. D.; Homola, Jiří; Moreno-Bondi, M. C.

    2010-01-01

    Roč. 398, č. 6 (2010), s. 2625-2634 ISSN 1618-2642 R&D Projects: GA AV ČR KAN200670701; GA MŠk OC09058 Institutional research plan: CEZ:AV0Z20670512 Keywords : Microcystin-LR * Label-free biosensor * Surface plasmon resonance Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.841, year: 2010

  17. Comprehensive insights into microcystin-LR effects on hepatic lipid metabolism using cross-omics technologies

    International Nuclear Information System (INIS)

    Zhang, Zongyao; Zhang, Xu-Xiang; Wu, Bing; Yin, Jinbao; Yu, Yunjiang; Yang, Liuyan

    2016-01-01

    Highlights: • Use of cross-omics technologies to evaluate toxic effects of microcystin-LR. • Disturbance of hepatic lipid metabolism by oral exposure to microcystin-LR. • Crucial roles of gut microbial community shift in the metabolic disturbance induced by microcystin-LR. - Abstract: Microcystin-LR (MC-LR) can induce hepatic tissue damages and molecular toxicities, but its effects on lipid metabolism remain unknown. This study investigated the effects of MC-LR exposure on mice lipid metabolism and uncovered the underlying mechanism through metabonomic, transcriptomic and metagenomic analyses after administration of mice with MC-LR by gavage for 28 d. Increased liver weight and abdominal fat weight, and evident hepatic lipid vacuoles accumulation were observed in the mice fed with 0.2 mg/kg/d MC-LR. Serum nuclear magnetic resonance analysis showed that MC-LR treatment altered the levels of serum metabolites including triglyceride, unsaturated fatty acid (UFA) and very low density lipoprotein. Digital Gene Expression technology was used to reveal differential expression of hepatic transcriptomes, demonstrating that MC-LR treatment disturbed hepatic UFA biosynthesis and activated peroxisome proliferator-activated receptor (PPAR) signaling pathways via Pparγ, Fabp1 and Fabp2 over-expression. Metagenomic analyses of gut microbiota revealed that MC-LR exposure also increased abundant ratio of Firmicutes vs. Bacteroidetes in gut and altered biosynthetic pathways of various microbial metabolic and pro-inflammatory molecules. In conclusion, oral MC-LR exposure can induce hepatic lipid metabolism disorder mediated by UFA biosynthesis and PPAR activation, and gut microbial community shift may play an important role in the metabolic disturbance.

  18. Using of Daphnia pulex, Artemia salina and Tubifex tubifex for cyanobacterial microcystins toxicity detection

    Czech Academy of Sciences Publication Activity Database

    Kyselková, I.; Maršálek, Blahoslav

    2000-01-01

    Roč. 55, č. 6 (2000), s. 637-643 ISSN 0006-3088 R&D Projects: GA AV ČR KSK6005114 Grant - others:Cyanotox project ENVA(XX) CT98 0802; Cyanotox project ENVA(XX) EU DG-XII Institutional research plan: CEZ:AV0Z6005908 Keywords : cyanobacteria * microcystin * toxins * Slovakia Subject RIV: EF - Botanics Impact factor: 0.165, year: 2000

  19. Comprehensive insights into microcystin-LR effects on hepatic lipid metabolism using cross-omics technologies

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zongyao [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China); Center for Environmental Health Research, South China Institute of Environmental Sciences, The Ministry of Environmental Protection of PRC, Guangzhou 510655 (China); Zhang, Xu-Xiang, E-mail: zhangxx@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China); Wu, Bing; Yin, Jinbao [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China); Yu, Yunjiang [Center for Environmental Health Research, South China Institute of Environmental Sciences, The Ministry of Environmental Protection of PRC, Guangzhou 510655 (China); Yang, Liuyan, E-mail: yangly@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China)

    2016-09-05

    Highlights: • Use of cross-omics technologies to evaluate toxic effects of microcystin-LR. • Disturbance of hepatic lipid metabolism by oral exposure to microcystin-LR. • Crucial roles of gut microbial community shift in the metabolic disturbance induced by microcystin-LR. - Abstract: Microcystin-LR (MC-LR) can induce hepatic tissue damages and molecular toxicities, but its effects on lipid metabolism remain unknown. This study investigated the effects of MC-LR exposure on mice lipid metabolism and uncovered the underlying mechanism through metabonomic, transcriptomic and metagenomic analyses after administration of mice with MC-LR by gavage for 28 d. Increased liver weight and abdominal fat weight, and evident hepatic lipid vacuoles accumulation were observed in the mice fed with 0.2 mg/kg/d MC-LR. Serum nuclear magnetic resonance analysis showed that MC-LR treatment altered the levels of serum metabolites including triglyceride, unsaturated fatty acid (UFA) and very low density lipoprotein. Digital Gene Expression technology was used to reveal differential expression of hepatic transcriptomes, demonstrating that MC-LR treatment disturbed hepatic UFA biosynthesis and activated peroxisome proliferator-activated receptor (PPAR) signaling pathways via Pparγ, Fabp1 and Fabp2 over-expression. Metagenomic analyses of gut microbiota revealed that MC-LR exposure also increased abundant ratio of Firmicutes vs. Bacteroidetes in gut and altered biosynthetic pathways of various microbial metabolic and pro-inflammatory molecules. In conclusion, oral MC-LR exposure can induce hepatic lipid metabolism disorder mediated by UFA biosynthesis and PPAR activation, and gut microbial community shift may play an important role in the metabolic disturbance.

  20. Microcystin in aquatic food webs of the Baltic and Chesapeake Bay regions

    Science.gov (United States)

    Bukaveckas, Paul A.; Lesutienė, Jūratė; Gasiūnaitė, Zita R.; Ložys, Linas; Olenina, Irina; Pilkaitytė, Renata; Pūtys, Žilvinas; Tassone, Spencer; Wood, Joseph

    2017-05-01

    We undertook a comparative study of the James River Estuary, a sub-estuary of Chesapeake Bay, and the Curonian Lagoon, a sub-estuary of the Baltic Sea, to better understand the factors that determine the presence and persistence of algal toxins in food webs. Over a 2-year period, we measured microcystin concentrations in water, sediment and biota (fish and shellfish) at both sites. Across both food webs we found highest levels of microcystin among consumers of suspended particulate matter, including planktivorous fishes and filter-feeding shellfish, and lower levels of toxin among piscivores, scavengers and benthic omnivores. Despite similar levels of microcystin in the water column at the two sites, we observed higher toxin levels in fish and sediments of the Curonian Lagoon. We attribute this difference to the legacy of prior toxic cyanobacteria blooms in the Curonian Lagoon and hydrologic factors that result in a predominance of autochthonously-derived organic matter in the sediments at this site. Our results suggest that a consideration of species-specific differences in feeding habits, and organic matter sources supporting food webs are important to understanding the accumulation and persistence of algal toxins in food webs and should therefore be considered in assessment of risks to aquatic biota and human health.

  1. Theoretical spectroscopic study of the conjugate microcystin-LR-europium cryptate

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Julio G.; Dutra, Jose Diogo L.; Costa Junior, Nivan B. da; Freire, Ricardo O., E-mail: rfreire@ufs.br [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Departamento de Quimica; Alves Junior, Severino; Sa, Gilberto F. de [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Quimica Fundamental

    2013-02-15

    In this work, theoretical tools were used to study spectroscopic properties of the conjugate microcystin-LR-europium cryptate. The Sparkle/AM1 model was applied to predict the geometry of the system and the INDO/S-CIS model was used to calculate the excited state energies. Based on the Judd-Ofelt theory, the intensity parameters were predicted and a theoretical model based on the theory of the 4f-4f transitions was applied to calculate energy transfer and backtransfer rates, radiative and non-radiative decay rates, quantum efficiency and quantum yield. A detailed study of the luminescent properties of the conjugate Microcystin-LR-europium cryptate was carried out. The results show that the theoretical quantum yield of luminescence of 23% is in good agreement with the experimental value published. This fact suggests that this theoretical protocol can be used to design new systems in order to improve their luminescence properties. The results suggest that this luminescent system may be a good conjugate for using in assay ELISA for detection by luminescence of the Microcystin-LR in water. (author)

  2. A comprehensive immunoassay for the detection of microcystins in waters based on polyclonal antibodies

    International Nuclear Information System (INIS)

    Sheng Jianwu; He Miao; Shi Hanchang; Qian Yi

    2006-01-01

    Microcystins (MCs) are a group of closely related toxic cyclic heptapeptides produced by common cyanobacteria (blue-green algae), and microcystin-leucine-arginine (MC-LR) is among the most frequent and most toxic microcystin congeners. In this study, a free amino group was introduced to MC-LR at its seventh amino acid residue with 2-mercaptoethylamine, and the product aminoethyl-MC-LR was coupled to bovine serum albumin (BSA) and horseradish peroxidise (HRP) by glutaraldehyde to be complete antigen (MC-LR-BSA) and labelled hapten (MC-LR-HRP), respectively. Polyclonal antibodies against MC-LR were generated by immunization with MC-LR-BSA. A direct competitive enzyme-linked immunosorbent assay (dc-ELISA) was established to detect the MCs in waters, which showed a good cross-reactivity with MC-LR, MC-RR, MC-YR, MC-LF, MC-LW and nodularin, and have a detection limit for MC-LR 0.12 μg L -1 , the 50% inhibition concentration (IC 50 ) for MC-LR was 0.63 ± 0.06 μg L -1 and the quantitative detection range was from 0.17 to 2.32 μg L -1 , the analysis result of water samples showed good recovery and reliability. So the comprehensive and reliable dc-ELISA will well potentially suit for sensitive analysis for total MCs in drinking as well as resource water samples

  3. Presence of microcystin during events of algal blooms in Araruama Lagoon

    Directory of Open Access Journals (Sweden)

    Manildo Marcião de Oliveira

    2012-04-01

    Full Text Available Algal blooms are phenomena produced by anthropogenic activities, despite the possible natural causes. In Araruama Lagoon, blooms occurred in 2005 and in subsequent years, causing profound changes in phytoplankton communities. These episodes triggered events of extensive fish mortality associated with low levels of dissolved oxygen. Another adverse effect associated with blooms is the production of harmful toxins such as phycotoxins produced by eukaryotic microalgae and cyanotoxins produced by cyanobacteria. Samples of fish (mullet and menhaden and seston showed levels of microcystin by enzyme-linked immunosorbent assay (ELISA, also a seston sample (São Pedro d'Aldeia on 08/22/2007, in a period not related to fish mortality, showed cells which contained genes encoding microcystin synthetase, an enzyme responsible for the synthesis of microcystin. The succession of microalgae with the concomitant presence of potentially toxic cyanobacteria draws attention to the risk of chronic exposure by the population that uses fish as their main protein source.

  4. Microcystins and cyanophyte extracts inhibit or promote the photosynthesis of fluvial algae. Ecological and management implications.

    Science.gov (United States)

    García-Espín, Laura; Cantoral, Enrique A; Asencio, Antonia D; Aboal, Marina

    2017-07-01

    The ecological influence of cyanotoxins on aquatic biota remains unclear despite the numerous published references on toxicological and sanitary problems related with cyanophyte proliferation. The effects of microcystins and cyanophyte extracts on the photosynthesis of the algae that belong to two taxonomic groups, Rhodophyta and Bacillariophyta, were studied in an attempt to elucidate their role in the intraspecific competence and physiognomy of fluvial communities. The data showed that both cyanobacteria extracts and pure microcystin-LR affected the photosynthetic activity of all the tested organisms, diatoms (Fistulifera pelliculosa, Gomphonema parvulum, Nitzschia frustulum and Stephanodiscus minutulus) and red algae (Chroothece richteriana) at environmentally relevant concentrations. Effects varied with strains and time, and promoted or inhibited photosynthesis. The microcystins and the other compounds present in cyanobacteria extracts may explain the competence effects observed in nature, especially in calcareous environments where they predominate, and after disturbing events like heavy rains or floods, which may destroy cyanophyte mats and release toxic or inhibitory compounds in a seasonal scale pattern.

  5. Life strategy and grazing intensity responses of Brachionus calyciflorus fed on different concentrations of microcystin-producing and microcystin-free Microcystis aeruginosa.

    Science.gov (United States)

    Liang, Ye; Ouyang, Kai; Chen, Xinglan; Su, Yuqi; Yang, Jiaxin

    2017-02-23

    The occurrence of Microcystis blooms is a worldwide concern due to the numerous adverse effects on zooplankton. We therefore hypothesized that the cyanobacterium Microcystis aeruginosa is harmful to rotifer growth. Population and individual experiments were conducted with the same proportional volumes of Chlorella and Microcystis for given food densities. Life-table parameters, life-history traits, and the grazing intensity of Brachionus calyciflorus were evaluated after they had fed on microcystin-producing and microcystin-free Microcystis, both alone and combined with an edible alga (Chlorella pyrenoidosa), at concentrations of 1 × 10 5 , 1 × 10 6 , and 1 × 10 7 cells mL -1 . The results showed that the interactive effects of food density and type appeared to be synergistic on generation time (T), net reproduction rate (R 0 ), body length, swimming speed, and reproduction time. In contrast, these effects appeared to be antagonistic on intrinsic growth rate (r), finite rate of increase (λ), time to first brood, post-reproductive time and total offspring per female. The grazing rate of rotifers decreased with grazing time. Although the toxins released after grazing on M. aeruginosa had negative effects on rotifer growth and reproduction, B. calyciflorus changed its life strategy and grazing intensity in response to eutrophic conditions.

  6. Assessment of microcystins in lake water and fish (Mugilidae, Liza sp.) in the largest Spanish coastal lake.

    Science.gov (United States)

    Romo, Susana; Fernández, Francisca; Ouahid, Youness; Barón-Sola, Ángel

    2012-01-01

    Cyanobacteria dominance and cyanotoxin production can become major threats to humans and aquatic life, especially in warm shallow lakes, which are often dominated by cyanobacteria. This study investigates the occurrence and distribution of microcystins (MCYST) in water, cell-bound and in the tissues of the commercial mugilid Liza sp. in the largest, coastal, Spanish Mediterranean lake (Albufera of Valencia). This is the first report concerning microcystin accumulation in tissues of mugilid fish species. Considerable amounts of microcystins were found in the water and seston, which correlated with development of Microcystis aeruginosa populations in the lake. The MCYST concentrations found in Lake Albufera (mean 1.7 and 17 μg/L and maximum 16 and 120 μg/L in water and seston, respectively) exceeded by one to two orders of magnitude the guideline levels proposed by the World Health Organization and were higher than that reported in other lakes of the Mediterranean zone. The presence of MCYST was found in all the fishes studied and accumulated differently among tissues of the commercial species Liza sp. Toxin accumulation in fish tissues showed that although the target organ for MCYST was the liver, high concentrations of microcystins were also found in other analysed tissues (liver>intestine>gills>muscle). Human tolerable daily intake for microcystins is assessed relative to the WHO guidelines, and potential toxicological risks for humans, wildlife and related ecosystems of the lake are discussed.

  7. Evaluation of the transfer and the accumulation of microcystins in tomato (Solanum lycopersicum cultivar MicroTom) tissues using a cyanobacterial extract containing microcystins and the radiolabeled microcystin-LR ((14)C-MC-LR).

    Science.gov (United States)

    Corbel, Sylvain; Mougin, Christian; Nélieu, Sylvie; Delarue, Ghislaine; Bouaïcha, Noureddine

    2016-01-15

    Microcystins are the most common cyanotoxins and may be expected wherever blooms of cyanobacteria occur in surface waters. Their persistence both in the irrigation water and in the soil can lead to their transfer and bioaccumulation into agricultural plants. The aim of this work was to investigate microcystin accumulation in Solanum lycopersicum cultivar MicroTom. The plant was exposed to either Microcystis aeruginosa crude extracts containing up to 100 μg eq.MC-LRL(-1) in a soil-plant system for 90 days or pure radiolabeled (14)C-MC-LR in a hydroponic condition for 48 h. Toxin bioaccumulation in the soil and different plant tissues was assessed both by the PP2A inhibition assay and by liquid chromatography-mass spectrometry (LC/MS/MS). After 90 days of exposure, microcystins persisted in the soil and their free extractable concentrations accumulated were very low varying between 1.6 and 3.9 μg eq.MC-LR kg(-1) DW. Free MC-LR was detected only in roots and leaves with concentrations varying between 4.5 and 8.1 μg kg(-1) DW and between 0.29 and 0.55 μg kg(-1) DW, respectively. By using radioactivity ((14)C-MC-LR), the results have reported a growing accumulation of toxins within the organs roots>leaves>stems and allowed them to confirm the absence of MC-LR in fruits after 48 h of exposure. The bioconcentration factor (BCF) was 13.6 in roots, 4.5 in leaves, and 1.4 in stems. On the other hand, the results highlight the presence of two radioactive fractions in different plant tissues. The non-extractable fraction of radioactivity, corresponding to the covalently bound MC-LR, was higher than that of the extractable fraction only in roots and leaves reaching 56% and 71% of the total accumulated toxin, respectively. Therefore, results raise that monitoring programs must monitor the presence of MCs in the irrigation water to avoid the transfer and accumulation of these toxins in crops. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Genetic programming-based mathematical modeling of influence of weather parameters in BOD5removal by Lemna minor.

    Science.gov (United States)

    Chandrasekaran, Sivapragasam; Sankararajan, Vanitha; Neelakandhan, Nampoothiri; Ram Kumar, Mahalakshmi

    2017-11-04

    This study, through extensive experiments and mathematical modeling, reveals that other than retention time and wastewater temperature (T w ), atmospheric parameters also play important role in the effective functioning of aquatic macrophyte-based treatment system. Duckweed species Lemna minor is considered in this study. It is observed that the combined effect of atmospheric temperature (T atm ), wind speed (U w ), and relative humidity (RH) can be reflected through one parameter, namely the "apparent temperature" (T a ). A total of eight different models are considered based on the combination of input parameters and the best mathematical model is arrived at which is validated through a new experimental set-up outside the modeling period. The validation results are highly encouraging. Genetic programming (GP)-based models are found to reveal deeper understandings of the wetland process.

  9. [Microcystin in plants that treat water for human consumption in a tropical environment: the Metropolitan Area of Costa Rica].

    Science.gov (United States)

    Lopez, Adrián Avendaño; Villa, Carolina Arguedas

    2006-09-01

    We measured microcystin levels in water of the Metropolitan Area of Costa Rica by competitive inhibition ELISA and we quantified total coliforms, fecal coliforms, Escherichia coli (by a Most Probable Number method) and aerobic count. We wanted to identify any cyanotoxin correlation with these parameters, as a public health risk. We sampled in the rainy season of 2003 (April-October) and in the dry season of 2004 (February-March) (30 samples/season). We sampled pre-treated, semi-treated and treated water. Microcystin levels 0.5 ppb in the dry season). Dry season levels exceeded World Health Organization limits (1.0 ppb). Cyanotoxins occurred in the Tres Rios plant. We did not find a correlation between these microbiologic parameters of water quality and microcystin levels in water.

  10. Elevated pCO2 causes a shift towards more toxic microcystin variants in nitrogen-limited Microcystis aeruginosa.

    Science.gov (United States)

    Liu, Jing; Van Oosterhout, Elmer; Faassen, Elisabeth J; Lürling, Miquel; Helmsing, Nico R; Van de Waal, Dedmer B

    2016-02-01

    Elevated pCO2 may promote phytoplankton growth, and potentially alleviate carbon limitation during dense blooms. Under nitrogen-limited conditions, elevated pCO2 may furthermore alter the phytoplankton carbon-nitrogen (C:N) balance and thereby the synthesis of secondary metabolites, such as cyanobacterial toxins. A common group of these toxins are the microcystins, with variants that differ not only in C:N stoichiometry, but also in toxicity. Here, we hypothesized that elevated pCO2 will increase the cellular C:N ratios of cyanobacteria, thereby promoting the more toxic microcystin variants with higher C:N ratios. To test this hypothesis, we performed chemostat experiments under nitrogen-limited conditions, exposing three Microcystis aeruginosa strains to two pCO2 treatments: 400 and 1200 μatm. Biomass, cellular C:N ratios and total microcystin contents at steady state remained largely unaltered in all three strains. Across strains and treatments, however, cellular microcystin content decreased with increasing cellular C:N ratios, suggesting a general stoichiometric regulation. Furthermore, as predicted, microcystin variants with higher C:N ratios generally increased with elevated pCO2, while the variant with a low C:N ratio decreased. Thus, elevated pCO2 under nitrogen-limited conditions may shift the cellular microcystin composition towards the more toxic variants. Such CO2-driven changes may have consequences for the toxicity of Microcystis blooms. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Occurrence of cyanobacteria, microcystin, and taste-and-odor compounds in Cheney Reservoir, Kansas, 2001-16

    Science.gov (United States)

    Graham, Jennifer L.; Foster, Guy M.; Williams, Thomas J.; Kramer, Ariele R.; Harris, Theodore D.

    2017-03-31

    Cheney Reservoir, located in south-central Kansas, is one of the primary drinking-water supplies for the city of Wichita and an important recreational resource. Since 1990, cyanobacterial blooms have been present occasionally in Cheney Reservoir, resulting in increased treatment costs and decreased recreational use. Cyanobacteria, the cyanotoxin microcystin, and the taste-and-odor compounds geosmin and 2-methylisoborneol have been measured in Cheney Reservoir by the U.S. Geological Survey, in cooperation with the city of Wichita, for about 16 years. The purpose of this report is to describe the occurrence of cyanobacteria, microcystin, and taste-and-odor compounds in Cheney Reservoir during May 2001 through June 2016 and to update previously published logistic regression models that used continuous water-quality data to estimate the probability of microcystin and geosmin occurrence above relevant thresholds.Cyanobacteria, microcystin, and geosmin were detected in about 84, 52, and 31 percent of samples collected in Cheney Reservoir during May 2001 through June 2016, respectively. 2-methylisoborneol was less common, detected in only 3 percent of samples. Microcystin and geosmin concentrations exceeded advisory values of concern more frequently than cyanobacterial abundance; therefore, cyanobacteria are not a good indicator of the presence of these taste-and-odor compounds in Cheney Reservoir. Broad seasonal patterns in cyanobacteria and microcystin were evident, though abundance and concentration varied by orders of magnitude across years. Cyanobacterial abundances generally peaked in late summer or early fall (August through October), and smaller peaks were observed in winter (January through February). In a typical year, microcystin was first detected in June or July, increased to its seasonal maxima in the summer (July through September), and then decreased. Seasonal patterns in geosmin were less consistent than cyanobacteria and microcystin, but geosmin

  12. Diversidad genética entre especies del género lemna (lemnaceae utilizando fragmentos polimórficos de ADN amplificados al azar (rapds

    Directory of Open Access Journals (Sweden)

    Frank Solano Campos

    2016-03-01

    Full Text Available Lemna aequinoctialis and Lemna valdiviana were tested genetic similarity by random amplified polymorphic DNA (RAPD fingerprinting. Of 60 primers (10-mer tested, 26 generated polymorphic products. 143 bands were found from 200bp up to 1500bp, 109 were polymorphic (76,2%, with an average of 4,19. Of these, only 18 were specific of L. aequinoctialis, while 91 bands were specific for L. valdiviana. Data were used to generate Jaccard’s similarity coefficients and to construct a dendrogram using UPGMA method in the BiodiversityPro statistical package. It is concluded from this study that there were clear differences (high genetic diversity between L. aequinoctialis and L. valdiviana and that RAPD sesults are comparable with those obtained from studies on morphology, It is a practical method to assess the relationships between these species.

  13. Plant growth-promoting bacterium Acinetobacter calcoaceticus P23 increases the chlorophyll content of the monocot Lemna minor (duckweed) and the dicot Lactuca sativa (lettuce).

    Science.gov (United States)

    Suzuki, Wakako; Sugawara, Masayuki; Miwa, Kyoko; Morikawa, Masaaki

    2014-07-01

    Acinetobacter calcoaceticus P23 is a plant growth-promoting bacterium that was isolated from the surface of duckweed (Lemna aoukikusa). The bacterium was observed to colonize on the plant surfaces and increase the chlorophyll content of not only the monocotyledon Lemna minor but also the dicotyledon Lactuca sativa in a hydroponic culture. This effect on the Lactuca sativa was significant in nutrient-poor (×1/100 dilution of H2 medium) and not nutrient-rich (×1 or ×1/10 dilutions of H2 medium) conditions. Strain P23 has the potential to play a part in the future development of fertilizers and energy-saving hydroponic agricultural technologies. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  14. Synthesis of the (9R,13R)-isomer of LDS1, a flower-inducing oxylipin isolated from Lemna paucicostata.

    Science.gov (United States)

    Takayasu, Yuki; Ogura, Yusuke; Towada, Ryo; Kuwahara, Shigefumi

    2016-08-01

    The first synthesis of the (9R,13R)-stereoisomer of LDS1, a flower-inducing oxylipin isolated from Lemna paucicostata, has been achieved from a known allylic alcohol by a seven-step sequence that involves the Horner-Wadsworth-Emmons olefination to construct its full carbon framework and an enzymatic hydrolysis of a penultimate methyl ester intermediate to provide the target molecule.

  15. Carbon key-properties for microcystin adsorption in drinking water treatment: structure or surface chemistry?

    OpenAIRE

    Júlio, Maria de Fátima de Jesus Leal

    2011-01-01

    Dissertação para Obtenção de Grau de Mestre em Engenharia Química e Bioquímica The carbon key-properties (structure and surface chemistry) for microcystin-LR (MC-LR) adsorption onto activated carbon were investigated. Waters with an inorganic background matrix approaching that of the soft natural water (2.5 mM ionic strength) were used. Also, model waters with controlled ionic make-up and NOM surrogate with similar size of MC-LR (tannic acid - TA) with MC-LR extracts were tested with activ...

  16. Evaluation of the transfer and the accumulation of microcystins in tomato (Solanum lycopersicum cultivar MicroTom) tissues using a cyanobacterial extract containing microcystins and the radiolabeled microcystin-LR ({sup 14}C-MC-LR)

    Energy Technology Data Exchange (ETDEWEB)

    Corbel, Sylvain [INRA, UMR1402 ECOSYS, F-78850 Thiverval-Grignon (France); AgroParisTech, UMR1402 ECOSYS, F-78850 Thiverval-Grignon (France); Laboratoire Ecologie, Systématique et Evolution, UMR8079, Univ. Paris-Sud/CNRS/AgroParisTech, Université Paris-Sud, F-91405 Orsay (France); Mougin, Christian; Nélieu, Sylvie; Delarue, Ghislaine [INRA, UMR1402 ECOSYS, F-78850 Thiverval-Grignon (France); AgroParisTech, UMR1402 ECOSYS, F-78850 Thiverval-Grignon (France); Bouaïcha, Noureddine, E-mail: noureddine.bouaicha@u-psud.fr [Laboratoire Ecologie, Systématique et Evolution, UMR8079, Univ. Paris-Sud/CNRS/AgroParisTech, Université Paris-Sud, F-91405 Orsay (France)

    2016-01-15

    Microcystins are the most common cyanotoxins and may be expected wherever blooms of cyanobacteria occur in surface waters. Their persistence both in the irrigation water and in the soil can lead to their transfer and bioaccumulation into agricultural plants. The aim of this work was to investigate microcystin accumulation in Solanum lycopersicum cultivar MicroTom. The plant was exposed to either Microcystis aeruginosa crude extracts containing up to 100 μg eq. MC-LR L{sup −1} in a soil–plant system for 90 days or pure radiolabeled {sup 14}C-MC-LR in a hydroponic condition for 48 h. Toxin bioaccumulation in the soil and different plant tissues was assessed both by the PP2A inhibition assay and by liquid chromatography-mass spectrometry (LC/MS/MS). After 90 days of exposure, microcystins persisted in the soil and their free extractable concentrations accumulated were very low varying between 1.6 and 3.9 μg eq. MC-LR kg{sup −1} DW. Free MC-LR was detected only in roots and leaves with concentrations varying between 4.5 and 8.1 μg kg{sup −1} DW and between 0.29 and 0.55 μg kg{sup −1} DW, respectively. By using radioactivity ({sup 14}C-MC-LR), the results have reported a growing accumulation of toxins within the organs roots > leaves > stems and allowed them to confirm the absence of MC-LR in fruits after 48 h of exposure. The bioconcentration factor (BCF) was 13.6 in roots, 4.5 in leaves, and 1.4 in stems. On the other hand, the results highlight the presence of two radioactive fractions in different plant tissues. The non-extractable fraction of radioactivity, corresponding to the covalently bound MC-LR, was higher than that of the extractable fraction only in roots and leaves reaching 56% and 71% of the total accumulated toxin, respectively. Therefore, results raise that monitoring programs must monitor the presence of MCs in the irrigation water to avoid the transfer and accumulation of these toxins in crops. - Graphical abstract: Bioconcentration

  17. Reversed-phase liquid chromatographic-mass spectrometric determination of microcystin-LR in cyanobacteria blooms under alkaline conditions

    Czech Academy of Sciences Publication Activity Database

    Ruangyuttikarn, W.; Mikšík, Ivan; Pekkoh, J.; Peerapornpisal, Y.; Deyl, Zdeněk

    2004-01-01

    Roč. 800, č. 1-2 (2004), s. 315-319 ISSN 1570-0232 R&D Projects: GA ČR GA203/02/1467 Institutional research plan: CEZ:AV0Z5011922 Keywords : microcystin * HPLC/MS Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.176, year: 2004

  18. A Multi-Walled Carbon Nanotube-based Biosensor for Monitoring Microcystin-LR in Sources of Drinking Water Supplies

    Science.gov (United States)

    A multi-walled carbon nanotube-based electrochemical biosensor is developed for monitoring microcystin-LR (MC-LR), a toxic cyanobacterial toxin, in sources of drinking water supplies. The biosensor electrodes are fabricated using dense, mm-long multi-walled CNT (MWCNT) arrays gro...

  19. Concentrations and Seasonal Trends of Extracellular Microcystins in Freshwaters of the Czech Republic - Results of the National Monitoring Program

    Czech Academy of Sciences Publication Activity Database

    Bláhová, Lucie; Babica, Pavel; Maršálková, Eliška; Maršálek, Blahoslav; Bláha, Luděk

    2007-01-01

    Roč. 35, č. 4 (2007), s. 348-354 ISSN 1863-0650 R&D Projects: GA AV ČR(CZ) KJB6005411 Grant - others:-(CZ) 1M6798593901 Institutional research plan: CEZ:AV0Z60050516 Keywords : cyanobacterie * microcystin * drinking water Subject RIV: EF - Botanics

  20. Microcystin-LR equivalent concentrations in fish tissue during a postbloom Microcystis exposure in Loskop Dam, South Africa

    CSIR Research Space (South Africa)

    Nchabeleng, T

    2014-12-01

    Full Text Available The effects of a decomposing cyanobacteria bloom on water quality and the accumulation of microcystin-LR equivalent toxin in fish at Loskop Dam were studied in May 2012. Enzyme-linked immunosorbent assay [ELISA] was used to confirm the presence...

  1. Oxidation of microcystin-LR by the Fenton process : Kinetics, degradation intermediates, water quality and toxicity assessment

    NARCIS (Netherlands)

    Park, Jeong-Ann; Yang, Boram; Park, Chanhyuk; Choi, Jae-Woo; van Genuchten, Case M.; Lee, Sang-Hyup

    2017-01-01

    The Fenton process was assessed as a cost-effective technology for the removal of Microcystin-LR (MC-LR) among UV, UV/H2O2, and Fenton process according to efficiency and electrical energy per order (EE/O). The determined practical concentrations of the Fenton reagents were 5 mg/L Fe(II) and 5 mg/L

  2. Impact of microcystin containing diets on physiological performance of Nile tilapia (Oreochromis niloticus) concerning stress and growth

    Czech Academy of Sciences Publication Activity Database

    Ziková, A.; Trubiroha, A.; Wiegand, C.; Wuertz, S.; Rennert, B.; Pflugmacher, S.; Kopp, Radovan; Mareš, J.; Kloas, W.

    2010-01-01

    Roč. 29, č. 3 (2010), s. 561-568 ISSN 0730-7268 Institutional research plan: CEZ:AV0Z60050516 Keywords : microcystin * Nile tilapia * physiological performance Subject RIV: EF - Botanics Impact factor: 3.026, year: 2010

  3. First report of an Anabaena Bory strain containing microcystin-LR in a freshwater body in Africa

    CSIR Research Space (South Africa)

    Oberholster, Paul J

    2015-03-11

    Full Text Available In South Africa, little is known about the production of microcystin by the genus Anabaena Bory. In April 2012, during a cyanobacterial bloom event in Theewaterskloof Dam, Western Cape province, the plankton was sampled on 10 occasions. The dominant...

  4. Microcystin kinetics (bioaccumulation, elimination) and biochemical responses in common carp and silver carp exposed to toxic cyanobacterial blooms

    Czech Academy of Sciences Publication Activity Database

    Adamovský, Ondřej; Kopp, R.; Hilscherová, Klára; Babica, Pavel; Palíková, M.; Pašková, Veronika; Navrátil, S.; Maršálek, Blahoslav; Bláha, Luděk

    2007-01-01

    Roč. 26, č. 12 (2007), s. 2687-2693 ISSN 0730-7268 R&D Projects: GA MŠk 1M0571 Institutional research plan: CEZ:AV0Z60050516 Keywords : microcystin * carp * toxicokinetics Subject RIV: EF - Botanics Impact factor: 2.309, year: 2007

  5. Solar photo-Fenton treatment of microcystin-LR in aqueous environment: Transformation products and toxicity in different water matrices

    Science.gov (United States)

    Transformation products and toxicity patterns of microcystin-LR (MC-LR), a common cyanotoxin in freshwaters, during degradation by solar photo-Fenton process were studied in the absence and presence of two major water components, namely fulvic acid and alkalinity. The transformat...

  6. The interactive effects of ammonia and microcystin on life-history traits of the cladoceran Daphnia magna: synergistic or antagonistic?

    Directory of Open Access Journals (Sweden)

    Zhou Yang

    Full Text Available The occurrence of Microcystis blooms is a worldwide concern that has caused numerous adverse effects on water quality and lake ecology. Elevated ammonia and microcystin concentrations co-occur during the degradation of Microcystis blooms and are toxic to aquatic organisms; we studied the relative and combined effects of these on the life history of the model organism Daphnia magna. Ammonia and microcystin-LR treatments were: 0, 0.366, 0.581 mg L(-1 and 0, 10, 30, 100 µg L(-1, respectively. Experiments followed a fully factorial design. Incubations were 14 d and recorded the following life-history traits: number of moults, time to first batch of eggs, time to first clutch, size at first batch of eggs, size at first clutch, number of clutches per female, number of offspring per clutch, and total offspring per female. Both ammonia and microcystin were detrimental to most life-history traits. Interactive effects of the toxins occurred for five traits: the time to first batch of eggs appearing in the brood pouch, time to first clutch, size at first clutch, number of clutches, and total offspring per female. The interactive effects of ammonia and microcystin appeared to be synergistic on some parameters (e.g., time to first eggs and antagonistic on others (e.g., total offspring per female. In conclusion, the released toxins during the degradation of Microcystis blooms would result, according to our data, in substantially negative effect on D. magna.

  7. Chlorination and ozonation differentially reduced the microcystin content and tumour promoting activity of a complex cyanobacterial extract

    Czech Academy of Sciences Publication Activity Database

    Sovadinová, I.; Babica, Pavel; Adamovský, O.; Alpatova, A.; Tarabara, V.; Upham, B. L.; Bláha, L.

    2017-01-01

    Roč. 8, č. 1 (2017), s. 107-120 ISSN 1947-573X Institutional support: RVO:67985939 Keywords : microcystin * chlorination * ozonation * water treatment * toxicity Subject RIV: DJ - Water Pollution ; Quality OBOR OECD: Environmental sciences (social aspects to be 5.7)

  8. Immunomodulatory Potency of Microcystin, an Important Water-Polluting Cyanobacterial Toxin.

    Science.gov (United States)

    Adamovsky, Ondrej; Moosova, Zdena; Pekarova, Michaela; Basu, Amrita; Babica, Pavel; Svihalkova Sindlerova, Lenka; Kubala, Lukas; Blaha, Ludek

    2015-10-20

    Microcystins (MCs) are primarily hepatotoxins produced by cyanobacteria and are responsible for intoxication in humans and animals. There are many incidents of chronic exposure to MCs, which have been attributed to the inappropriate treatment of water supplies or contaminated food. Using RAW 264.7 macrophages, we showed the potency of microcystin-LR (MC-LR) to stimulate production of pro-inflammatory cytokines (tumor necrosis factor α and interleukin-6) as a consequence of fast nuclear factor κB and nitrogen-activated protein kinase activation. In contrast to other studies, the observed effects were not attributed to the intracellular inhibition of protein phosphatases 1/2A due to lack of specific transmembrane transporters for MCs. However, the MC-LR-induced activation of macrophages was effectively inhibited by a specific peptide that blocks signaling of receptors, which play a pivotal role in the innate immune responses. Taken together, we showed for the first time that MC-LR could interfere with macrophage receptors that are responsible for triggering the above-mentioned signaling pathways. These findings provide an interesting mechanistic explanation of some adverse health outcomes associated with toxic cyanobacteria and MCs.

  9. [Isolation, identification and characterization of a microcystin-degrading bacterium Paucibacter sp. strain CH].

    Science.gov (United States)

    You, Di-Jie; Chen, Xiao-Guo; Xiang, Hui-Yi; Ouyang, Liao; Yang, Bing

    2014-01-01

    A bacterium capable of degrading microcystin (MC), strain CH, was isolated from the sediment of Lake Chaohu, China. Strain CH was tentatively identified as Paucibacter sp. based on the analysis of 16S rRNA gene sequences. Paucibacter sp. strain CH can use microcystin LR (MCLR) as the sole carbon and energy sources, and 11.6 microg x mL(-1) of MCLR was degraded to below the detection limit within 10 hours with the first-order reaction rate constant of 0.242 h(-1). The optimum temperature and initial pH for MC degradation were 25-30 degrees C and pH 6-9, respectively. A novel intermediate product containing the Adda residue was detected during the degradation of MCLR, which is different from those produced by strain ACM-3962, and Adda was recognized as the final product of the degradation process. Furthermore, no homologue to any of the four genes, mlrA, mlrB, mlrC and mlrD previously associated with the degradation of MCLR by strain ACM-3962 was found in strain CH. These findings suggest that Paucibacter sp. strain CH mighe degrade MC through a different pathway from that of strain ACM-3962.

  10. Microcystin-LR removal from Microcystis aeruginosa using in natura sugarcane bagasse and activated carbon

    Directory of Open Access Journals (Sweden)

    Aline Rafaela de Almeida

    2016-03-01

    Full Text Available Microcystin-LR is a type of toxin released by the Microcystis aeruginosa cyanobacteria found in water sources used for human consumption. It can cause illness and even death if not completely removed in conventional water treatment. The retention of this toxin is often accomplished by the adsorption process in activated carbon in water treatment plants. In this study, a comparison was made between the retention of microcystin-LR by activated carbon and by sugarcane bagasse in natura applied as a bio-adsorbent. Adsorption experiments were performed after the physical and chemical properties of the bio adsorbent and the activated carbon were characterized. The adsorption performance was evaluated by the toxin removal efficiency and the maximum adsorption capacity. Average removal efficiencies of the toxin resulted in 65.25; 41.74 and 11.75% for the activated carbon and 24.15; 18.92 and 12.27% for the sugarcane bagasse for concentrations of 2.36, 3.33 and 3.83 µg L-1, respectively. The bio adsorbent presented removal efficiency for the toxin similar to that observed in the activated carbon for the concentration of 3.83 µg L-1. Maximum adsorption capacity obtained with better linear adjustment to the Freundlich isotherm was 6,047.84 µg g-1 (toxin concentration of 3.83 µg L-1 for sugarcane bagasse and 338.61 µg g-1 (toxin concentration of 2.36 µg L-1 for activated carbon.

  11. Adsorption of Ten Microcystin Congeners to Common Laboratory-Ware Is Solvent and Surface Dependent

    Directory of Open Access Journals (Sweden)

    Stefan Altaner

    2017-04-01

    Full Text Available Cyanobacteria can produce heptapetides called microcystins (MC which are harmful to humans due to their ability to inhibit cellular protein phosphatases. Quantitation of these toxins can be hampered by their adsorption to common laboratory-ware during sample processing and analysis. Because of their structural diversity (>100 congeners and different physico-chemical properties, they vary in their adsorption to surfaces. In this study, the adsorption of ten different MC congeners (encompassing non-arginated to doubly-arginated congeners to common laboratory-ware was assessed using different solvent combinations. Sample handling steps were mimicked with glass and polypropylene pipettes and vials with increasing methanol concentrations at two pH levels, before analysis by liquid chromatography-tandem mass spectrometry. We demonstrated that MC adsorb to polypropylene surfaces irrespective of pH. After eight successive pipet actions using polypropylene tips ca. 20% of the MC were lost to the surface material, which increased to 25%–40% when solutions were acidified. The observed loss was alleviated by changing the methanol (MeOH concentration in the final solvent. The required MeOH concentration varied depending on which congener was present. Microcystins only adsorbed to glass pipettes (loss up to 30% after eight pipet actions when in acidified aqueous solutions. The latter appeared largely dependent on the presence of ionizable groups, such as arginine residues.

  12. Influence of Cyanobacterial Bloom on Freshwater Biocoenosis. Use of Bioassays for Cyanobacterial Microcystins Toxicity Assessment

    Directory of Open Access Journals (Sweden)

    Piontek Marlena

    2017-03-01

    Full Text Available The issues presented in this study concern a very important problem of the occurrence of cyanobacterial blooms in surface water used for water supply purposes. The objective of this study was to analyze the occurrence of cyanotoxic risk in the catchment area of the Obrzyca River (including Sławskie lake which is the beginning of the river, which is a source of drinking water for the inhabitants of Zielona Góra. In order to evaluate toxicity of cyanobacterial bloom it was conducted toxicological testing using aquatic invertebrates (Daphnia magna, Dugesia tigrina and heterotrophic bacteria (Escherichia coli, Enterococcus faecalis, Pseudomonas fluorescens. Test samples were collected from May to October, 2012. The most toxic was a sample collected from Lake Sławskie on 20th October when cyanobacteria bloom with a predominance of Microcystis aeruginosa occurred and the amount of microcystins was the largest. The methanol extract of the sample was toxic only above a concentration of 6·103 mg·dm-3. The lethal concentration (48-h LC 50 for Daphnia magna was 3.09·103 and for Dugesia tigrina (240-h LC 50 1.51·103 mg·dm-3 of microcystins (MC-LR, MC-YR and MC-RR. The same extract stimulated growth of Escherichia coli and Enterococcus faecalis cells.

  13. Effects of microcystin-LR on Saccharomyces cerevisiae growth, oxidative stress and apoptosis.

    Science.gov (United States)

    Valério, Elisabete; Vilares, Arminda; Campos, Alexandre; Pereira, Paulo; Vasconcelos, Vitor

    2014-11-01

    Microcystins (MC) are cyanotoxins occurring globally, known for causing acute hepatotoxicity in humans/animals, tumor promotion in animals and potential carcinogenicity. The mechanism of MC toxicity is considered a multi-pathway process involving the inhibition of protein phosphatases PP1/PP2A and the production of reactive oxygen species (ROS). However, their mechanism of action is not fully characterized, thus hampering the complete hazard identification. In this study, we evaluated the effect of several microcystin-LR concentrations on the growth, ROS levels, antioxidant system response and apoptosis induction on Saccharomyces cerevisiae. Our results showed that the growth of S. cerevisiae was not inhibited when compared to control cells. However, the staining of cells with DHR123 and DHE revealed an intracellular increase of the ROS levels. This ROS increase resulted in an augment of catalase activity and inhibition of SOD. All these facts suggest that hydrogen peroxide was the main ROS induced by MCLR. Signs of apoptosis were also detected in the cells exposed to toxin. Our results show that S. cerevisiae VL3 displays MCLR toxicity effects known to occur in higher eukaryotes and confirmed that it can be a simple and good model to help further in the elucidation of MCLR molecular mechanisms of toxicity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Using H2O2 treatments for the degradation of cyanobacteria and microcystins in a shallow hypertrophic reservoir.

    Science.gov (United States)

    Papadimitriou, Theodoti; Kormas, Konstantinos; Dionysiou, Dionysios D; Laspidou, Chrysi

    2016-11-01

    Toxins produced by cyanobacteria in freshwater ecosystems constitute a serious health risk worldwide for humans that may use the affected water bodies for recreation, drinking water, and/or irrigation. Cyanotoxins have also been deemed responsible for loss of animal life in many places around the world. This paper explores the effect of H 2 O 2 treatments on cyanobacteria and microcystins in natural samples from a hypertrophic reservoir in microcosm experiments. According to the results, cyanobacteria were more easily affected by H 2 O 2 than by other phytoplanktonic groups. This was shown by the increase in the fractions of chlorophyll-a (a proxy for phytoplankton) and chlorophyll-b (a proxy for green algae) over total phytoplankton pigments and the decrease in the fraction of phycocyanin (a proxy for cyanobacteria) over total phytoplankton pigments. Thus, while an overall increase in phytoplankton occurred, a preferential decrease in cyanobacteria was observed with H 2 O 2 treatments over a few hours. Moreover, significant degradation of total microcystins was observed under H 2 O 2 treatments, while more microcystins were degraded when UV radiation was used in combination with H 2 O 2 . The combination of H 2 O 2 and ultraviolet (UV) treatment in natural samples resulted in total microcystin concentrations that were below the World Health Organization limit for safe consumption of drinking water of 1 μg/L. Although further investigation into the effects of H 2 O 2 addition on ecosystem function must be performed, our results show that the application of H 2 O 2 could be a promising method for the degradation of microcystins in reservoirs and the reduction of public health risks related to the occurrence of harmful algal blooms.

  15. Detection of microcystin and other cyanotoxins in lakes at Isle Royale National Park, Pictured Rocks National Lakeshore, and Sleeping Bear Dunes National Lakeshore, northern Michigan, 2012–13

    Science.gov (United States)

    Fuller, Lori M.; Brennan, Angela K.; Fogarty, Lisa R.; Loftin, Keith A.; Johnson, Heather E.; VanderMeulen, David D.; Lafrancois, Brenda Moraska

    2017-12-05

    Although cyanotoxins released during algal blooms have become an increasing concern in surface waters across the United States, the presence of cyanotoxins in northern Michigan lakes had not been evaluated in detail. The U.S. Geological Survey and National Park Service (NPS) led a 2-year study (2012 and 2013) to determine the presence of microcystin and other algal toxins in several inland lakes at Isle Royale National Park (hereafter referred to as ISRO, Pictured Rocks National Lakeshore (hereafter referred to as PIRO), and Sleeping Bear Dunes National Lakeshore (hereafter referred to as SLBE). Samples also were collected at four sites in Lake Michigan within the SLBE. The two analytical techniques used in the study were enzyme-linked immunosorbent assays (ELISA) for microcystin, cylindrospermopsin, and saxitoxin; and liquid chromatography/tandem mass spectrometry (LC/MS/MS) for a larger suite of algal toxins. Neither cylindrospermopsin nor saxitoxin were detected in the 211 samples. Microcystin was detected in 31 percent of samples (65 of 211 samples) analyzed by the ELISA method, but no sample results exceeded the World Health Organization recreational health advisory standard for microcystin (10 micrograms per liter [µg/L]). However, about 10 percent of the samples (21 of 211 samples) that were collected from PIRO and SLBE and were analyzed by ELISA for microcystin had concentrations greater than the U.S. Environmental Protection Agency (EPA) drinking water 10-day health advisory of 0.3 µg/L for children preschool age and younger (less than 6-years old). One sample collected in 2012 from SLBE exceeded the EPA drinking water 10-day health advisory of 1.6 µg/L for school-age children through adults (6-years old and older). In 2012, the highest concentration of 2.7 µg/L was detected in Florence Lake within SLBE. Many visitors enjoy recreation in or on the water and camp in the backcountry at these national parks where the most common source of drinking water

  16. Biochemical parameters of blood plasma and content of microcystins in tissues of common carp (Cyprinus carpio L.) from hypertrophic pond with cyanobacterial water bloom

    Czech Academy of Sciences Publication Activity Database

    Kopp, Radovan; Mareš, J.; Palíková, M.; Navrátil, S.; Kubíček, Z.; Ziková, A.; Hlávková, J.; Bláha, Luděk

    2009-01-01

    Roč. 40, č. 15 (2009), s. 1683-1693 ISSN 1355-557X Institutional research plan: CEZ:AV0Z60050516 Keywords : microcystin * aquaculture * biochemistry Subject RIV: EF - Botanics Impact factor: 1.099, year: 2009

  17. Performance of the macrophyte Lemna valdiviana in tertiary pig waste treatment and its contribution to the sustainability of swine production

    Directory of Open Access Journals (Sweden)

    Flávio R. Lapolli

    2008-03-01

    Full Text Available The present study aims to contribute to the sustainability of swine production by evaluating usage of the aquatic macrophyte Lemna valdiviana in the tertiary treatment of pig waste. Five assays (1 to 5 in triplicate were conducted using swine effluent with different COD (Chemical Oxygen Demand concentrations: 400, 550, 700, 850 and 1,000mg.L-1, respectively. The trial lasted for 21 days and the evaluated variables were: (a pollutant removal efficiency, (b biomass production and (c plant protein content under the different detention times of 7, 14 and 21 days. In general, assays 1 and 2 (CODs of 400 and 550mg.L-1 presented the best removal efficiencies under a detention time of 21 days. Regarding the purpose of both nutrient removal and production of high protein biomass, assay 3 (COD of 700mg.L-1 showed the best results under 14 days’ detention time (36.81% crude protein. It was established that the use of duckweeds in the tertiary swine waste treatment was able to provide a sustainable alternative regarding its advantages such as effluent polishing, minimization of environmental impact, and production of high protein feed.

  18. Effects of exposure to nano and bulk sized TiO2and CuO in Lemna minor.

    Science.gov (United States)

    Dolenc Koce, Jasna

    2017-10-01

    Nanoparticles of TiO 2 and CuO are among most commonly used nanoparticles, and elevated concentrations of them are expected to be found in all environments, including aquatic. A standard growth inhibition test ISO/CD 20079 was used to determine the toxicity of nano sized and larger micro sized (bulk) particles in the concentrations of 0.1, 1, 10, 100 and 1000 μM CuO and TiO 2 on common duckweed (Lemna minor L.). Both nano and bulk CuO particles caused changes in the structure and function of treated plants. The number of fronds and colonies decreased by as much as 78%, the length of roots and fronds decreased by 99% and 14%, respectively. Furthermore, photochemical efficiency was reduced by up to 35%, and the activities of antioxidative enzymes guaiacol peroxidase, ascorbate peroxidase and glutathione reductase increased by more than 240%. The altered physiological state of the CuO exposed plants was also reflected in the elevated occurrence of necrosis and bleaching in the duckweed colonies. Nano sized particles of CuO proved more phytotoxic than bulk particles, and the effects of both studied CuO sizes were concentration dependent. On the other hand, both bulk and nano sized particles of TiO 2 caused no severe phytotoxic effects, there was no concentration dependence and they could be considered as non-harmful to common duckweed. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  19. Risk of combined exposure of birds to cyanobacterial biomass containing microcystins, acetylcholinesterase inhibitor and anticoagulant.

    Science.gov (United States)

    Ondracek, Karel; Bandouchova, Hana; Damkova, Veronika; Hilscherova, Klara; Kral, Jiri; Osickova, Jitka; Mlcakova, Veronika; Pohanka, Miroslav; Skochova, Hana; Vitula, Frantisek; Treml, Frantisek; Pikula, Jiri

    2012-01-01

    The objective of this study was to examine the hypothesis that a combination of cyanobacterial biomass containing microcystins, acetylcholinesterase inhibitor and anticoagulant can enhance avian toxic effects produced by single exposures only. A total of 48 two-month-old Japanese quails (Coturnix coturnix japonica) with average body weight of 160 g were randomly divided into 8 experimental groups of six birds and sex ratio of 1:1. Experimental groups of control Japanese quails (C) and birds exposed to single and combined sub-lethal doses of paraoxon (P), bromadiolone (B), and microcystins in cyanobacterial biomass (M) included: C, P, P+B, B, B+M, P+M, M, and P+B+M. During the 10-day exposure birds in the respective groups received biomass containing 61.62 µg microcystins daily (i.e. 26.54 µg MC-RR, 7.62 µg MC-YR and 27.39 µg MC-LR), two 250 μg/kg doses of paraoxon, and two 500 mg/kg doses of bromadiolone. Group responses were compared using standard plasma biochemistry and antioxidant/oxidative stress parameters in tissues. While single and double combinations of toxicants induced responses in individual biochemical parameters measured and evaluated using univariate statistical analysis, those in the triple exposure were most extensive. The principal component analysis of antioxidant/oxidative stress parameters (glutathione reductase, lipid peroxidation, and ferric reducing antioxidant power) in tissues (liver, kidney, heart, brain, lungs, gonads, and pectoralis major muscle) clearly separated the triple group (P+B+M) from all single and double exposure groups and the control and indicated thus marked joint effects in the overall pattern of antioxidant/oxidative stress responses of this group. The separation was driven by the modification of the ferric reducing antioxidant power levels in heart and brain and the cardiac lipid peroxidation level, in particular. This experiment contributes to the understanding of the pathogenic mechanisms of combined sub

  20. Ciliate Nassula sp. grazing on a microcystin-producing cyanobacterium (Planktothrix agardhii): impact on cell growth and in the microcystin fractions

    Energy Technology Data Exchange (ETDEWEB)

    Combes, Audrey; Dellinger, Marc [' Molecules de communication et adaptation des microorganismes' , UMR 7245 CNRS-MNHN, Museum national d' Histoire naturelle, CP 39, 57 rue Cuvier, F-75231 Paris Cedex 05 (France); Cadel-six, Sabrina [' Unite Caracterisation des Toxines' - Laboratoire de securite des aliments de Maisons-Alfort - ANSES, F-94701 Maisons Alfort Cedex (France); Amand, Severine [' Molecules de communication et adaptation des microorganismes' , UMR 7245 CNRS-MNHN, Museum national d' Histoire naturelle, CP 39, 57 rue Cuvier, F-75231 Paris Cedex 05 (France); Comte, Katia, E-mail: kcomte@mnhn.fr [' Molecules de communication et adaptation des microorganismes' , UMR 7245 CNRS-MNHN, Museum national d' Histoire naturelle, CP 39, 57 rue Cuvier, F-75231 Paris Cedex 05 (France)

    2013-01-15

    The proliferation of microcystins (MCs)-producing cyanobacteria (MCs) can have detrimental effects on the food chain in aquatic environments. Until recently, few studies had focused on the fate of MCs in exposed organisms, such as primary consumers of cyanobacteria. In this study, we investigate the impact of an MC-producing strain of the cyanobacterium Planktothrix agardhii on the growth and physiology of a Nassula sp. ciliate isolated from a non-toxic cyanobacterial bloom. We show that this Nassula sp. strain was able to consume and grow while feeding exclusively on an MC-producing cyanobacterium over a prolonged period of time (8 months). In short-term exposure experiments (8 days), ciliates consuming an MC-producing cyanobacterial strain displayed slower growth rate and higher levels of antioxidant enzymes than ciliates feeding on two non-MC-producing strains. Three high-performance methods (LC/MS, LC/MS-MS and ELISA) were used to quantify the free and bound MCs in the culture medium and in the cells. We show that ciliate grazing led to a marked decrease in free MCs (methanol extractable) in cells, the MCs were therefore no longer found in the surrounding culture medium. These findings suggest that MCs may have undergone redistribution (free vs bound MCs) or chemical degradation within the ciliates.

  1. Factors Affecting Temporal and Spatial Variations of Microcystins in Gonghu Bay of Lake Taihu, with Potential Risk of Microcystin Contamination to Human Health

    Directory of Open Access Journals (Sweden)

    Qing Wang

    2010-01-01

    Full Text Available A field survey of the seasonal variation of microcystin (MC concentration was performed in Gonghu Bay (a total of 15 sampling sites of Lake Taihu from January to December 2008. Microcystis spp. biomass and intra-/extracellular MCs were significantly correlated with water temperature, suggesting the importance of temperature in cyanobacterial blooming in the lake. Higher MC concentration was found in summer and autumn, and peaks of Microcystis biomass and intra-/extracellular MC concentrations were all present in October. Spatially, risk of MCs was higher in littoral zones than in the pelagic area. There were significant correlations between N or P concentrations, and Microcystis biomass or MC content, suggesting that N and P levels affected MC production through influencing Microcystis biomass. Intra-/extracellular MCs and Microcystis biomass had negative exponential relationships with TN:TP, and the maximum values all occurred when TN:TP was <25. Multivariate analyses by pcca indicated that intra- and extracellular MC concentrations had better correlations with biological factors (such as Microcystis biomass and chl-a than physicochemical factors. The maximum concentration reached up to 17 µg/L MC-Lreq, considerably higher drinking water safety standard (1 µg/L recommended who. So it is necessary take measures reduce exposure risk of cyanobacterial toxins human beings.

  2. Evaluation of Five Treatment Plants for the Removal of Microcystins in Drinking Water

    Directory of Open Access Journals (Sweden)

    Manuel Álvarez Cortiñas

    2017-06-01

    Full Text Available In Galicia there are supplies that collect water from reservoirs showing growth of cyanobacteria that could produce toxins. The drinking water treatment plants (DWTPs of these supplies should provide adequate treatment and be subjected to maintenance. WHO guidelines make recommendations on the most suitable treatments for removing microcystins. The Department of Health developed a protocol of action against these events jointly with water basin authorities. 4 reservoirs and five treatment plants were identified for this study. The treatments of the plants, the maintenance carried out at the DWTPs and the results for sestonic and dissolved toxins analyzed by the Public Health Laboratory of Galicia in the reservoirs near the point of collection, before the treatment plants and after them, during the 2013-2014 biennium were evaluated.

  3. Biochemical indices are modulated in fish exposed to cyanobacterial toxins (microcystins

    Directory of Open Access Journals (Sweden)

    Jana Hlávková

    2008-01-01

    Full Text Available In this work were summarized changes of biochemical markers of fish under the thumb of cyanobacterial toxins (microcystins. Among the most studied biomarkers of the influence of cyanobacterial toxins on fish belong oxidative stress parameters – glutathione S-transferase (GST, non-enzymatic antioxidant glutathione (GSH, superoxide dismutase (SOD, catalase (CAT, glutathione peroxidase (GPx, lipid peroxidation (LPO, malondialdehyde (MDA, glutatione reductase (GR, parameters of blood – values of haemoglobin (Hb, haematocrit (PCV, mean corpuscular haemoglobin concentration (MCHC, mean corpuscular volume (MCV, mean corpuscular haemoglobin (MCH, erythrocyte (RBC, leukocyte counts (WBC and plasma – alanine aminotransferase (ALT, aspartate aminotransferase (AST, lactate dehydrogenase (LDH, alkaline phosphatase (ALP, cholinesterase (CHE, total serum protein (TP, glucose (GLU, lactate (LACT, iron (Fe, calcium (Ca, magnesium (Mg, total bilirubin (BIL, phosphorus (P and protein phosphatase activities (PP1, PP2A.

  4. Photocatalytic Removal of Microcystin-LR by Advanced WO3-Based Nanoparticles under Simulated Solar Light

    Science.gov (United States)

    Zhao, Chao; Li, Dawei; Feng, Chuanping; Zhang, Zhenya; Sugiura, Norio; Yang, Yingnan

    2015-01-01

    A series of advanced WO3-based photocatalysts including CuO/WO3, Pd/WO3, and Pt/WO3 were synthesized for the photocatalytic removal of microcystin-LR (MC-LR) under simulated solar light. In the present study, Pt/WO3 exhibited the best performance for the photocatalytic degradation of MC-LR. The MC-LR degradation can be described by pseudo-first-order kinetic model. Chloride ion (Cl−) with proper concentration could enhance the MC-LR degradation. The presence of metal cations (Cu2+ and Fe3+) improved the photocatalytic degradation of MC-LR. This study suggests that Pt/WO3 photocatalytic oxidation under solar light is a promising option for the purification of water containing MC-LR. PMID:25884038

  5. Microcystins contamination of surface water supply sources in Zaria-Nigeria.

    Science.gov (United States)

    Chia, Mathias Ahii; Kwaghe, Mndepawe Jonah

    2015-10-01

    Cyanobacterial contamination of public water supply systems is a worldwide problem. The present study investigated water quality and microcystins (MCs) contamination of four public water supply systems in Zaria, Nigeria. The water bodies were eutrophic in the rainy and dry season and supported high phytoplankton biomass with chlorophyll a concentrations generally higher than 20.0 μg/L. The biomass of the predominant species (Microcystis aeruginosa and Anabaena subcylindrica) of cyanobacteria had a significant positive correlation with particulate and dissolved MCs. Dissolved MCs concentrations were higher (>1.0 μg/L) than the maximum permissible limits for drinking water in all the water bodies in the dry season and three of them in the rainy season. These results suggest that there is the need to have a regular monitoring program for these water bodies to prevent acute and chronic health hazards associated with MCs contamination of drinking and irrigation water.

  6. Effects of the naturally-occurring contaminant microcystins on the Azolla filiculoides-Anabaena azollae symbiosis.

    Science.gov (United States)

    Pereira, A L; Monteiro, B; Azevedo, J; Campos, A; Osório, H; Vasconcelos, V

    2015-08-01

    Harmful algal blooms (HABs) contaminate aquatic ecosystems and are responsible for animal poisoning worldwide. We conducted a toxicity test with the aquatic fern and the biofertilizer, Azolla filiculoides. The sporophytes were exposed to three concentrations (0.01, 0.1 and 1μgmL(-1)) of a microcystin (MC) cyanobacterial crude extract and purified MC-LR. The growth of A. filiculoides decreased only at 1μgmL(-1) crude extract concentration while with MC-LR it decreased at all the tested concentrations, indicating that the presence of other compounds in the crude extract altered toxicity and stimulated the fern growth at lower concentrations (0.01 and 0.1μgmL(-1)). Both phycoerythrocyanin and allophycocyanin levels decreased in all the concentrations of crude extract and MC-LR. The phycocyanin had a marked increase at 0.1μgmL(-1) crude extract concentration and a marked decrease at 1μgmL(-1) MC-LR concentration. These changes in the phycobiliprotein content indicate a shift in the antenna pigments of the cyanobionts of A. filiculoides. The changes in two oxidative stress enzymes, glutathione reductase for the crude extract assay and glutathione peroxidase for MC-LR assay, points towards the induction of stress defense responses. The low bioconcentration factor in both crude extract and MC-LR treatments can suggest the low uptake of microcystins, and indicates that the aquatic fern can be used as a biofertilizer and as animal feed but is not suitable for MC phytoremediation. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Degradation of microcystin-RR using boron-doped diamond electrode.

    Science.gov (United States)

    Zhang, Chunyong; Fu, Degang; Gu, Zhongze

    2009-12-30

    Microcystins (MCs), produced by blue-green algae, are one of the most common naturally occurring toxins found in natural environment. The presence of MCs in drinking water sources poses a great threat to people's health. In this study, the degradation behavior of microcystin-RR on boron-doped diamond (BDD) electrode was investigated under galvanostatic conditions. Such parameters as reaction time, supporting electrolyte and applied current density were varied in order to determine their effects on this oxidation process. The experimental results revealed the suitability of electrochemical processes employing BDD electrode for removing MC-RR from the solution. However, the efficient removal of MC-RR only occurred in the presence of sodium chloride that acted as redox mediators and the reaction was mainly affected by the chloride concentration (c(NaCl)) and applied current density (I(appl)). Full and quick removal of 0.50 microg/ml MC-RR in solution was achieved when the operating conditions of c(NaCl) and I(appl) were 20mM and 46.3 mA/cm(2), or 35 mM and 18.2 mA/cm(2) respectively. The kinetics for MC-RR degradation followed a pesudo-first order reaction in most cases, indicating the process was under mass transfer control. As a result of its excellent performance, the BDD technology could be considered as a promising alternative to promote the degradation of MC-RR than chlorination in drinking water supplies.

  8. First report on the occurrence of microcystins in planktonic cyanobacteria from Central Mexico.

    Science.gov (United States)

    Vasconcelos, Vitor; Martins, António; Vale, Micaela; Antunes, Agostinho; Azevedo, Joana; Welker, Martin; Lopez, Oscar; Montejano, Gustavo

    2010-09-01

    Although toxic cyanobacteria are commonly described worldwide, only one recent paper on the toxicity of cyanobacteria in Mexico has been published reporting the occurrence of cylindrospermopsin and saxitoxins. Microcystins are the most commonly studied cyanotoxins in many countries and those that may cause the most dramatic problems in terms of human health. In this paper, we studied the occurrence of potentially toxic cyanobacteria in different ecosystems in Central Mexico. Samples were collected in natural lakes (Zumpango, Laguna Atotonilco and Cienega Chica), reservoirs (Los Angeles and Valle de Bravo), man-made channels (Cuemanco, Tlameleca) and urban lakes (Chapultepec). A multi-technique approach was applied by the use of molecular, immunological and chemical techniques. Cyanobacteria were found in all the sites, ranging from 1.6 x 10(3) cells/mL in Tlameleca to 7.5 x 10(6) cells/mL in Chapultepec Grande, representing between 67 and 100% of the total phytoplankton density. The concentration of total microcystins varied between 4.9 and 78.0 microg MC-LR eq/L. The results revealed the occurrence of MC-LR in all the sites analyzed by MALDI-TOF, and MC-FR, MC-RR and MC-H(4)YR in two sites. Most of the studied sites are used either as a source of drinking water, as a recreational area, or for agriculture irrigation purposes, so the risk for human health may be high if not properly monitored. This is the first report on the MC profiles and concentrations in blooms collected in Mexico. Copyright 2010 Elsevier Ltd. All rights reserved.

  9. Cyanobacterial occurrence and detection of microcystins and saxitoxins in reservoirs of the Brazilian semi-arid

    Directory of Open Access Journals (Sweden)

    Jessica Roberts Fonseca

    2015-03-01

    Full Text Available Aim:The rapid spread of cyanobacteria in water sources and reservoirs has caused serious environmental damage and public health problems, and consists in a problem that challenges the institutions responsible for providing water to the population. In this study, the quantification of microcystin, saxitoxins and cyanobacteria levels was performed over 3 years in the semi-arid reservoirs of Rio Grande do Norte (Brazil. In addition, we analyzed the seasonal distribution of cyanotoxins and the percentage of cyanobacteria and cyanotoxins which were above the limit established by Brazilian law.MethodsThe study was conducted between 2009 and 2011 in four dams with six sites: Armando Ribeiro Gonçalves (ARG in Itajá, San Rafael (SR and Jucurutu; Passagem das Traíras (PT; Itans and Gargalheiras (GARG. Cyanobacteria presence were quantified and identified and the presence of microcystins (MCYs and saxitoxins (STXs was investigated by ELISA.ResultsThe densities of cyanobacteria were found to be above the permitted in 76% of cases. The ELISA results showed that of the 128 samples analyzed, 27% were above the maximum allowed by the Brazilian Ministry of Health Order 2914/2011. A seasonal pattern for the presence of MCYs was found (0.00227 to 24.1954 µg.L–1, with the highest values in the rainy season. There was no clear seasonal pattern for STXs (0.003 to 0.766 µg.L–1.ConclusionsThis study showed the importance of establishing a water quality monitoring for human consumption and its potability standards since the concentration of MCYs in some samples was above the maximum limit allowed by Brazilian law, thus posing a risk to public health since the conventional water treatment is not able to eliminate these potent hepatotoxins.

  10. Physiological and antioxidant responses of Medicago sativa-rhizobia symbiosis to cyanobacterial toxins (Microcystins) exposure.

    Science.gov (United States)

    El Khalloufi, Fatima; Oufdou, Khalid; Lahrouni, Majida; Faghire, Mustapha; Peix, Alvaro; Ramírez-Bahena, Martha Helena; Vasconcelos, Vitor; Oudra, Brahim

    2013-12-15

    Toxic cyanobacteria in freshwaters can induce potent harmful effects on growth and development of plants irrigated with contaminated water. In this study, the effect of cyanobacteria extract containing Microcystins (MC) on Medicago sativa-rhizobia symbiosis was investigated in order to explore plants response through biomass production, photosynthetic pigment and antioxidant enzymes analysis: Peroxidase (POD), Polyphenoloxidase (PPO) and Catalase (CAT). Alfalfa plants were inoculated with two endosymbiotic rhizobial strains: RhOL1 (MC less sensitive strain) and RhOL3 (MC more sensitive strain), to evaluate the rhizobial contribution on the plant response cultured under cyanobacterial toxins stress. The two rhizobia strains were identified as Ensifer meliloti by sequence analysis of their rrs and atpD genes. The chronic exposure to MC extract showed shoot, root and nodules dry weight decrease, in both symbiosis cultures. The rate of decline in plants inoculated with RhOL3 was higher than that in symbiosis with RhOL1 mainly at 20 μg L(-1) of MC. Cyanotoxins also reduced photosynthetic pigment content and generated an oxidative stress observed at cellular level. POD, PPO and CAT activities were significantly increased in leaves, roots and nodules of alfalfa plants exposed to MC. These enzyme activities were higher in plants inoculated with RhOL3 especially when alfalfa plants were exposed to 20 μg L(-1) of MC. The present paper reports new scientific finding related to the behavior of rhizobia-M. sativa associations to MC (Microcystins) for later recommendation concerning the possible use of these symbiosis face to crops exposure to MC contaminated water irrigation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Removal of microcystin-LR from drinking water using a bamboo-based charcoal adsorbent modified with chitosan.

    Science.gov (United States)

    Zhang, Hangjun; Zhu, Guoying; Jia, Xiuying; Ding, Ying; Zhang, Mi; Gao, Qing; Hu, Ciming; Xu, Shuying

    2011-01-01

    A new kind of low-cost syntactic adsorbent from bamboo charcoal and chitosan was developed for the removal of microcystin-LR from drinking water. Removal efficiency was higher for the syntactic adsorbent when the amount of bamboo charcoal was increased. The optimum dose ratio of bamboo charcoal to chitosan was 6:4, and the optimum amount was 15 mg/L; equilibrium time was 6 hr. The adsorption isotherm was non-linear and could be simulated by the Freundlich model (R2 = 0.9337). Adsorption efficiency was strongly affected by pH and natural organic matter (NOM). Removal efficiency was 16% higher at pH 3 than at pH 9. Efficiency rate was reduced by 15% with 25 mg/L NOM (UV254 = 0.089 cm(-1)) in drinking water. This study demonstrated that the bamboo charcoal modified with chitosan can effectively remove microcystin-LR from drinking water.

  12. Influence of nutrient medium composition on uranium toxicity and choice of the most sensitive growth related endpoint in Lemna minor.

    Science.gov (United States)

    Horemans, Nele; Van Hees, May; Saenen, Eline; Van Hoeck, Arne; Smolders, Valérie; Blust, Ronny; Vandenhove, Hildegarde

    2016-01-01

    Uranium (U) toxicity is known to be highly dependent on U speciation and bioavailability. To assess the impact of uranium on plants, a growth inhibition test was set up in the freshwater macrophyte Lemna minor. First growth media with different compositions were tested in order to find a medium fit for testing U toxicity in L. minor. Following arguments were used for medium selection: the ability to sustain L. minor growth, a high solubility of U in the medium and a high percentage of the more toxic U-species namely UO2(2+). Based on these selection criteria a with a low phosphate concentration of 0.5 mg L(-1) and supplemented with 5 mM MES (2-(N-morpholino)ethanesulfonic acid) to ensure pH stability was chosen. This medium also showed highest U toxicity compared to the other tested media. Subsequently a full dose response curve for U was established by exposing L. minor plants to U concentrations ranging from 0.05 μM up to 150 μM for 7 days. Uranium was shown to adversely affect growth of L. minor in a dose dependent manner with EC10, EC30 and EC50 values ranging between 1.6 and 4.8 μM, 7.7-16.4 μM and 19.4-37.2 μM U, respectively, depending on the growth endpoint. Four different growth related endpoints were tested: frond area, frond number, fresh weight and dry weight. Although differences in relative growth rates and associated ECx-values calculated on different endpoints are small (maximal twofold difference), frond area is recommended to be used to measure U-induced growth effects as it is a sensitive growth endpoint and easy to measure in vivo allowing for measurements over time. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Ecotoxicological evaluation of propranolol hydrochloride and losartan potassium to Lemna minor L. (1753) individually and in binary mixtures.

    Science.gov (United States)

    Godoy, Aline A; Kummrow, Fábio; Pamplin, Paulo Augusto Z

    2015-07-01

    Antihypertensive pharmaceuticals, including the beta-blockers, are one of the most detected therapeutic classes in the environment. The ecotoxicity of propranolol hydrochloride and losartan potassium was evaluated, both individually and combined in a binary mixture, by using the Lemna minor growth inhibition test. The endpoints evaluated in the single-pharmaceutical tests were frond number, total frond area and fresh weight. For the evaluation of the mixture toxicity, the selected endpoint was frond number. Water quality criteria values (WQC) were derived for the protection of freshwater and saltwater pelagic communities regarding the effects induced by propranolol and losartan using ecotoxicological data from the literature, including our data. The risks associated with both pharmaceutical effects on non-target organisms were quantified through the measured environmental concentration (MEC)/predicted-no-effect concentration (PNEC) ratios. For propranolol, the total frond area was the most sensitive endpoint (EC50 = 77.3 mg L(-1)), while for losartan there was no statistically significant difference between the endpoints. Losartan is only slightly more toxic than propranolol. Both concentration addition and independent action models overestimated the mixture toxicity of the pharmaceuticals at all the effect concentration levels evaluated. The joint action of both pharmaceuticals showed an antagonistic interaction to L. minor. Derived WQC assumed lower values for propranolol than for losartan. The MEC/PNEC ratios showed that propranolol may pose a risk for the most sensitive aquatic species, while acceptable risks posed by losartan were estimated for most of aquatic matrices. To the authors knowledge these are the first data about losartan toxicity for L. minor.

  14. Getting More Ecologically Relevant Information from Laboratory Tests: Recovery of Lemna minor After Exposure to Herbicides and Their Mixtures.

    Science.gov (United States)

    Knežević, Varja; Tunić, Tanja; Gajić, Pero; Marjan, Patricija; Savić, Danko; Tenji, Dina; Teodorović, Ivana

    2016-11-01

    Recovery after exposure to herbicides-atrazine, isoproturon, and trifluralin-their binary and ternary mixtures, was studied under laboratory conditions using a slightly adapted standard protocol for Lemna minor. The objectives of the present study were (1) to compare empirical to predicted toxicity of selected herbicide mixtures; (2) to assess L. minor recovery potential after exposure to selected individual herbicides and their mixtures; and (3) to suggest an appropriate recovery potential assessment approach and endpoint in a modified laboratory growth inhibition test. The deviation of empirical from predicted toxicity was highest in binary mixtures of dissimilarly acting herbicides. The concentration addition model slightly underestimated mixture effects, indicating potential synergistic interactions between photosynthetic inhibitors (atrazine and isoproturon) and a cell mitosis inhibitor (trifluralin). Recovery after exposure to the binary mixture of atrazine and isoproturon was fast and concentration-independent: no significant differences between relative growth rates (RGRs) in any of the mixtures (IC10 Mix , 25 Mix , and 50 Mix ) versus control level were recorded in the last interval of the recovery phase. The recovery of the plants exposed to binary and ternary mixtures of dissimilarly acting herbicides was strictly concentration-dependent. Only plants exposed to IC10 Mix , regardless of the herbicides, recovered RGRs close to control level in the last interval of the recovery phase. The inhibition of the RGRs in the last interval of the recovery phase compared with the control level is a proposed endpoint that could inform on reversibility of the effects and indicate possible mixture effects on plant population recovery potential.

  15. Citric acid enhanced the antioxidant defense system and chromium uptake by Lemna minor L. grown in hydroponics under Cr stress.

    Science.gov (United States)

    Sallah-Ud-Din, Rasham; Farid, Mujahid; Saeed, Rashid; Ali, Shafaqat; Rizwan, Muhammad; Tauqeer, Hafiz Muhammad; Bukhari, Syed Asad Hussain

    2017-07-01

    Phytoextraction is a cost-effective and eco-friendly technique for the removal of pollutants, mainly heavy metal(loids) especially from polluted water and metal-contaminated soils. The phytoextraction of heavy metals is, in general, limited due to the low availability of heavy metals in the growth medium. Organic chelators can help to improve the phytoextraction by increasing metal mobility and solubility in the growth medium. The present research was carried out to examine the possibility of citric acid (CA) in improving chromium (Cr) phytoextraction by Lemna minor (duckweed). For this purpose, healthy plants were collected from nearby marsh and grown in hydroponics under controlled conditions. Initial metal contents of both marsh water and plant were measured along with physico-chemical properties of the marsh water. Different concentrations of Cr and CA were applied in the hydroponics in different combinations after defined intervals. Continuous aeration was supplied and pH maintained at 6.5 ± 0.1. Results showed that increasing concentration of Cr significantly decreased the plant biomass, photosynthetic pigments, leaf area, and antioxidant enzyme activities (like catalase, ascorbate peroxidase, superoxide dismutase, peroxidase). Furthermore, Cr stress increased the Cr concentrations, electrolyte leakage, hydrogen peroxide, and malondialdehyde contents in plants. The addition of CA alleviated the Cr-induced toxicity in plants and further enhanced the Cr uptake and its accumulation in L. minor. The addition of CA enhanced the Cr concentration in L. minor by 6.10, 26.5, 20.5, and 20.2% at 0, 10, 100, and 200 μM Cr treatments, respectively, compared to the respective Cr treatments without CA. Overall, the results of the present study showed that CA addition may enhance the Cr accumulation and tolerance in L. minor by enhancing the plant growth and activities of antioxidant enzymes.

  16. Development of a silicone-membrane passive sampler for monitoring cylindrospermopsin and microcystin LR-YR-RR in natural waters

    Science.gov (United States)

    Nyoni, Hlengilizwe; Mamba, Bhekie B.; Msagati, Titus A. M.

    2017-08-01

    Silicone membrane tubes were functionalised by filling them with synthesised γ-Fe2O3 nanoparticles and used as a passive sampling device for monitoring microcystins and cylindrospermopsin in aquatic environments. This novel device was calibrated for the measurement of microcystin and cylindrospermopsin concentrations in water. The effect of temperature and hydrodynamics on the sampler performance was studied in a flow-through system under controlled conditions. The chemical uptake of microcystins (MCs) and cylindrospermopsin (CYN) into the passive sampler remained linear and integrative throughout the exposure period. The rate of accumulation of most of the MC compounds tested was dependent on temperature and flow velocity. The use of 13C labelled polychlorinated biphenyls as performance reference compounds (PRCs) in silicone membrane/γ-Fe2O3 nanoparticle passive sampler, Chemcatcher and polar organic chemical integrative sampler (POCIS) was evaluated. The majority of PRCs improved the semi quantitative nature of water concentration estimated by the three samplers. The corrected sampling rate values of model biotoxin compounds were used to estimate the time-weighted average concentrations in natural cyanobacterial water blooms of the Hartbeespoort dam. The corrected sampling rates RScorr values varied from 0.1140 to 0.5628 Ld-1 between samplers with silicone membrane having the least RScorr values compared to the Chemcatcher and POCIS. The three passive sampling devises provided a more relevant picture of the biotoxin concentration in the Hartbeespoort dam. The results suggested that the three sampling devices are suitable for use in monitoring microcystins and cylindrospermopsin concentrations in aquatic environments.

  17. Experimental additions of aluminum sulfate and ammonium nitrate to in situ mesocosms to reduce cyanobacterial biovolume and microcystin concentration

    Science.gov (United States)

    Harris, Ted D.; Wilhelm, Frank M.; Graham, Jennifer L.; Loftin, Keith A.

    2014-01-01

    Recent studies suggest that nitrogen additions to increase the total nitrogen:total phosphorus (TN:TP) ratio may reduce cyanobacterial biovolume and microcystin concentration in reservoirs. In systems where TP is >100 μg/L, however, nitrogen additions to increase the TN:TP ratio could cause ammonia, nitrate, or nitrite toxicity to terrestrial and aquatic organisms. Reducing phosphorus via aluminum sulfate (alum) may be needed prior to nitrogen additions aimed at increasing the TN:TP ratio. We experimentally tested this sequential management approach in large in situ mesocosms (70.7 m3) to examine effects on cyanobacteria and microcystin concentration. Because alum removes nutrients and most seston from the water column, alum treatment reduced both TN and TP, leaving post-treatment TN:TP ratios similar to pre-treatment ratios. Cyanobacterial biovolume was reduced after alum addition, but the percent composition (i.e., relative) cyanobacterial abundance remained unchanged. A single ammonium nitrate (nitrogen) addition increased the TN:TP ratio 7-fold. After the TN:TP ratio was >50 (by weight), cyanobacterial biovolume and abundance were reduced, and chrysophyte and cryptophyte biovolume and abundance increased compared to the alum treatment. Microcystin was not detectable until the TN:TP ratio was <50. Although both treatments reduced cyanobacteria, only the nitrogen treatment seemed to stimulate energy flow from primary producers to zooplankton, which suggests that combining alum and nitrogen treatments may be a viable in-lake management strategy to reduce cyanobacteria and possibly microcystin concentrations in high-phosphorus systems. Additional studies are needed to define best management practices before combined alum and nitrogen additions are implemented as a reservoir management strategy.

  18. Community Needs Assessment After Microcystin Toxin Contamination of a Municipal Water Supply - Lucas County, Ohio, September 2014.

    Science.gov (United States)

    McCarty, Carolyn L; Nelson, Leigh; Eitniear, Samantha; Zgodzinski, Eric; Zabala, Amanda; Billing, Laurie; DiOrio, Mary

    2016-09-09

    On August 1, 2014, routine testing at the Collins Park Water Treatment Plant in Lucas County, Ohio, revealed microcystin toxin levels in drinking water had reached 3.19 μg/L, surpassing the Ohio Environmental Protection Agency (EPA) drinking water advisory threshold of 1.0 μg/L. Microcystin is a hepatoxin released by cyanobacteria in certain harmful algal blooms. Exposure to microcystin has been associated with gastrointestinal and hepatic illness in both humans and animals (1-3). On August 2, a do-not-drink advisory was issued, warning community members not to drink, boil, or use the water for cooking or brushing teeth. Public health officials used traditional and social media outlets to disseminate public health messages to affected communities. On August 4, 2014, the advisory was lifted after multiple water samples confirmed microcystin toxin levels had dropped below the advisory threshold. To assess communication strategies, water exposure, and household needs, the Ohio Department of Health (ODH) and Toledo-Lucas County Health Department (TLCHD) conducted a Community Assessment for Public Health Emergency Response (CASPER) in Lucas County. Most households (88.1%) reported hearing about the advisory the morning it was issued, but 11% reported drinking and 21% reported brushing teeth with municipal water during the advisory. Household members reported physical (16%) and mental (10%) health concerns that they believed were related to the advisory and activity disruptions including temporarily staying outside of the home (6%) during the advisory and continued use of alternative water sources after the advisory was lifted (82%). During a do-not-drink advisory, governmental agencies and community partners need to engage in joint prevention and response efforts to decrease water exposure and prevent activity disruptions.

  19. In situ studies on the distribution patterns and dynamics of microcystins in a biomanipulation fish - bighead carp (Aristichthys nobilis)

    Energy Technology Data Exchange (ETDEWEB)

    Chen Jun [Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7, Wuhan, Hubei 430072 (China); Xie Ping [Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7, Wuhan, Hubei 430072 (China)]. E-mail: xieping@ihb.ac.cn; Zhang Dawen [Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7, Wuhan, Hubei 430072 (China); Lei Hehua [Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7, Wuhan, Hubei 430072 (China)

    2007-05-15

    The distribution and dynamics of microcystins in various organs of the phytoplanktivorous bighead carp were studied monthly in Lake Taihu, which is dominated by toxic cyanobacteria. There was a good agreement between LC-MS and HPLC-UV determinations. Average recoveries of spiked fish samples were 63% for MC-RR and 71% for MC-LR. The highest MC contents in intestine, liver, kidney and spleen were 85.67, 2.83, 1.70 and 1.57 {mu}g g{sup -1} DW, respectively. MCs were much higher in mid-gut walls (1.22 {mu}g g{sup -1} DW) than in hind- and fore-gut walls (0.31 and 0.18 {mu}g g{sup -1} DW, respectively), suggesting the importance of mid-gut wall as major site for MC absorption. A cysteine conjugate of MC-LR was detected frequently in kidney. Among the muscle samples analyzed, 25% were above the provisional tolerable daily intake level by WHO. Bighead is strongly resistant to microcystins and can be used as biomanipulation fish to counteract cyanotoxin contamination in eutrophic waters. - Bighead carp is resistant to microcystins and can be used as biomanipulation fish to counteract cyanotoxin contamination.

  20. Complex interactions among nutrients, chlorophyll-a, and microcystins in three stormwater wet detention basins with floating treatment wetlands.

    Science.gov (United States)

    Hartshorn, Nicholas; Marimon, Zachary; Xuan, Zhemin; Cormier, Jessica; Chang, Ni-Bin; Wanielista, Martin

    2016-02-01

    Stormwater wet detention ponds hold a permanent pool of water and offer many beneficial uses including flood mitigation, pollution prevention, downstream erosion control, increased aesthetics, and recreational uses. Although the removal of nutrients is generally low for stormwater wet detention ponds in urban areas, floating treatment wetlands (FTWs) can be installed to offer an innovative solution toward naturally removing excess nutrients and aiding in stormwater management. To improve the stormwater reuse potential, this study assessed nutrient, microcystin, and chlorophyll-a interactions in three Florida stormwater wet detention ponds with recently implemented FTWs. Both episodic (storm events) and routine (non-storm events) sampling campaigns were carried out at the three ponds located in Ruskin, Gainesville, and Orlando. The results showed a salient negative correlation between total phosphorus and microcystin concentrations for both storm and non-storm events across all three ponds. The dominant nutrient species in correlation seemed to be total phosphorus, which correlated positively with chlorophyll-a concentrations at all ponds and sampling conditions, with the exception of Orlando non-storm events. These results showed a correlation conditional to the candidate pond and sampling conditions for microcystin and chlorophyll-a concentrations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Microcystin Contamination in Sea Mussel Farms from the Italian Southern Adriatic Coast following Cyanobacterial Blooms in an Artificial Reservoir

    Directory of Open Access Journals (Sweden)

    De Pace Rita

    2014-01-01

    Full Text Available An experimental study was performed in 2009-2010 to investigate the polluting effect of eutrophic inland waters communicating with the sea coast. The study was planned after a heavy and long-lasting Planktothrix rubescens bloom occurred in the Lake Occhito, an artificial reservoir. The waters of the reservoir flow into the southern Adriatic Sea, near several marine breeding of Mytilus galloprovincialis mussels, a typical seafood from the Apulia region (Southern Italy. A monitoring study of water and mussels from the sea coast of northern Apulia region and on the Occhito reservoir was carried out over twelve months, to get more information regarding the contamination by cyanobacteria and related cyanotoxins. Elisa immunoassay analyses estimated total microcystin amounts from 1.73 to 256 ng/g in mussels, up to 0.61 μg/L in sea water and up to 298.7 μg/L in lake water. Analyses of some samples of free-living marine clams as well as of marine and freshwater fish proved microcystin contamination. Selective confirmatory analyses by LC/ESI-Q-ToF-MS/MS on some mussel samples identified the microcystin desMe-MC-RR as the major toxin; this compound has been reported in the literature as a specific marker toxin of Planktothrix rubescens blooms. Our study describes for the first time the direct relationship between environmental pollution and food safety, caused by seafood contamination from freshwater toxic blooms.

  2. Dynamics of protein phosphatase gene expression in Corbicula fluminea exposed to microcystin-LR and to toxic Microcystis aeruginosa cells.

    Science.gov (United States)

    Martins, José Carlos; Machado, João; Martins, António; Azevedo, Joana; OlivaTeles, Luís; Vasconcelos, Vitor

    2011-01-01

    This study investigated the in vivo effects of microcystins on gene expression of several phosphoprotein phosphatases (PPP) in the freshwater clam Corbicula fluminea with two different exposure scenarios. Clams were exposed for 96 h to 5 μg L(-1) of dissolved microcystin-LR and the relative changes of gene expression of three different types of PPP (PPP1, 2 and 4) were analyzed by quantitative real-time PCR. The results showed a significant induction of PPP2 gene expression in the visceral mass. In contrast, the cyanotoxin did not cause any significant changes on PPP1 and PPP4 gene expression. Based on these results, we studied alterations in transcriptional patterns in parallel with enzymatic activity of C. fluminea for PPP2, induced by a Microcystis aeruginosa toxic strain (1 × 10(5) cells cm(-3)) during 96 h. The relative changes of gene expression and enzyme activity in visceral mass were analyzed by quantitative real-time PCR and colorimetric assays respectively. The clams exhibited a significant reduction of PPP2 activity with a concomitant enhancement of gene expression. Considering all the results we can conclude that the exposure to an ecologically relevant concentration of pure or intracellular microcystins (-LR) promoted an in vivo effect on PPP2 gene expression in C. fluminea.

  3. Dynamics of Protein Phosphatase Gene Expression in Corbicula fluminea Exposed to Microcystin-LR and to Toxic Microcystis aeruginosa Cells

    Directory of Open Access Journals (Sweden)

    Vitor Vasconcelos

    2011-12-01

    Full Text Available This study investigated the in vivo effects of microcystins on gene expression of several phosphoprotein phosphatases (PPP in the freshwater clam Corbicula fluminea with two different exposure scenarios. Clams were exposed for 96 h to 5 µg L−1 of dissolved microcystin-LR and the relative changes of gene expression of three different types of PPP (PPP1, 2 and 4 were analyzed by quantitative real-time PCR. The results showed a significant induction of PPP2 gene expression in the visceral mass. In contrast, the cyanotoxin did not cause any significant changes on PPP1 and PPP4 gene expression. Based on these results, we studied alterations in transcriptional patterns in parallel with enzymatic activity of C. fluminea for PPP2, induced by a Microcystis aeruginosa toxic strain (1 × 105 cells cm−3 during 96 h. The relative changes of gene expression and enzyme activity in visceral mass were analyzed by quantitative real-time PCR and colorimetric assays respectively. The clams exhibited a significant reduction of PPP2 activity with a concomitant enhancement of gene expression. Considering all the results we can conclude that the exposure to an ecologically relevant concentration of pure or intracellular microcystins (-LR promoted an in vivo effect on PPP2 gene expression in C. fluminea.

  4. Land use patterns, ecoregion, and microcystin relationships in U.S. lakes and reservoirs: a preliminary evaluation

    Science.gov (United States)

    Beaver, John R.; Manis, Erin E.; Loftin, Keith A.; Graham, Jennifer L.; Pollard, Amina I.; Mitchell, Richard M.

    2014-01-01

    A statistically significant association was found between the concentration of total microcystin, a common class of cyanotoxins, in surface waters of lakes and reservoirs in the continental U.S. with watershed land use using data from 1156 water bodies sampled between May and October 2007 as part of the USEPA National Lakes Assessment. Nearly two thirds (65.8%) of the samples with microcystin concentrations ≥1.0 μg/L (n = 126) were limited to three nutrient and water quality-based ecoregions (Corn Belt and Northern Great Plains, Mostly Glaciated Dairy Region, South Central Cultivated Great Plains) in watersheds with strong agricultural influence. canonical correlation analysis (CCA) indicated that both microcystin concentrations and cyanobacteria abundance were positively correlated with total nitrogen, dissolved organic carbon, and temperature; correlations with total phosphorus and water clarity were not as strong. This study supports a number of regional lake studies that suggest that land use practices are related to cyanobacteria abundance, and extends the potential impacts of agricultural land use in watersheds to include the production of cyanotoxins in lakes.

  5. A marriage of convenience; a simple food chain comprised of Lemna minor (L.) and Gammarus pulex (L.) to study the dietary transfer of zinc.

    Science.gov (United States)

    Lahive, E; O'Halloran, J; Jansen, M A K

    2015-01-01

    Macrophytes contribute significantly to the cycling of metals in aquatic systems, through accumulation during growth and release during herbivory or decomposition. Accumulation of high levels of metals has been extensively documented in Lemnaceae (duckweeds). However, the degree of trophic transfer of metals from Lemnaceae to secondary consumers remains poorly understood. This study demonstrates that zinc accumulated in Lemna minor is bioavailable to the herbivore consumer Gammarus pulex. Overall, the higher the zinc content of L. minor, the more zinc accumulated in G. pulex. Accumulation in G. pulex was such that mortality occurred when they were fed high zinc-containing L. minor. Yet, the percentage of consumed zinc retained by G. pulex actually decreased with higher zinc concentrations in L. minor. We hypothesise that this decrease reflects internal zinc metabolism, including a shift from soluble to covalently bound zinc in high zinc-containing L. minor. Consistently, relatively more zinc is lost through depuration when G. pulex is fed L. minor with high zinc content. The developed Lemna-Gammarus system is simple, easily manipulated, and sensitive enough for changes in plant zinc metabolism to be reflected in metal accumulation by the herbivore, and therefore suitable to study ecologically relevant metal cycling in aquatic ecosystems. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  6. Effects of microcystin-LR, cylindrospermopsin and a microcystin-LR/cylindrospermopsin mixture on growth, oxidative stress and mineral content in lettuce plants (Lactuca sativa L.).

    Science.gov (United States)

    Freitas, Marisa; Azevedo, Joana; Pinto, Edgar; Neves, Joana; Campos, Alexandre; Vasconcelos, Vitor

    2015-06-01

    Toxic cyanobacterial blooms are documented worldwide as an emerging environmental concern. Recent studies support the hypothesis that microcystin-LR (MC-LR) and cylindrospermopsin (CYN) produce toxic effects in crop plants. Lettuce (Lactuca sativa L.) is an important commercial leafy vegetable that supplies essential elements for human nutrition; thus, the study of its sensitivity to MC-LR, CYN and a MC-LR/CYN mixture is of major relevance. This study aimed to assess the effects of environmentally relevant concentrations (1, 10 and 100 µg/L) of MC-LR, CYN and a MC-LR/CYN mixture on growth, antioxidant defense system and mineral content in lettuce plants. In almost all treatments, an increase in root fresh weight was obtained; however, the fresh weight of leaves was significantly decreased in plants exposed to 100 µg/L concentrations of each toxin and the toxin mixture. Overall, GST activity was significantly increased in roots, contrary to GPx activity, which decreased in roots and leaves. The mineral content in lettuce leaves changed due to its exposure to cyanotoxins; in general, the mineral content decreased with MC-LR and increased with CYN, and apparently these effects are time and concentration-dependent. The effects of the MC-LR/CYN mixture were almost always similar to the single cyanotoxins, although MC-LR seems to be more toxic than CYN. Our results suggest that lettuce plants in non-early stages of development are able to cope with lower concentrations of MC-LR, CYN and the MC-LR/CYN mixture; however, higher concentrations (100 µg/L) can affect both lettuce yield and nutritional quality. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Associations between chlorophyll a and various microcystin-LR health advisory concentrations [version 1; referees: 1 approved, 2 approved with reservations

    Directory of Open Access Journals (Sweden)

    Jeffrey W. Hollister

    2016-02-01

    Full Text Available Cyanobacteria harmful algal blooms (cHABs are associated with a wide range of adverse health effects that stem mostly from the presence of cyanotoxins. To help protect against these impacts, several health advisory levels have been set for some toxins. In particular, one of the more common toxins, microcystin-LR, has several advisory levels set for drinking water and recreational use. However, compared to other water quality measures, field measurements of microcystin-LR are not commonly available due to cost and advanced understanding required to interpret results. Addressing these issues will take time and resources. Thus, there is utility in finding indicators of microcystin-LR that are already widely available, can be estimated quickly and in situ, and used as a first defense against high concentrations of microcystin-LR. Chlorophyll a is commonly measured, can be estimated in situ, and has been shown to be positively associated with microcystin-LR. In this paper, we use this association to provide estimates of chlorophyll a concentrations that are indicative of a higher probability of exceeding select health advisory concentrations for microcystin-LR. Using the 2007 National Lakes Assessment and a conditional probability approach, we identify chlorophyll a concentrations that are more likely than not to be associated with an exceedance of a microcystin-LR health advisory level. We look at the recent US EPA health advisories for drinking water as well as the World Health Organization levels for drinking water and recreational use and identify a range of chlorophyll a thresholds. A 50% chance of exceeding one of the microcystin-LR advisory concentrations of 0.3, 1, 1.6, and 2 g/L is associated with chlorophyll a concentration thresholds of 23.4, 67.0, 83.5, and 105.8, respectively. When managing for these various microcystin-LR levels, exceeding these reported chlorophyll a concentrations should be a trigger for

  8. Evaluation of phytotoxicity and ecotoxicity potentials of a cyanobacterial extract containing microcystins under realistic environmental concentrations and in a soil-plant system.

    Science.gov (United States)

    Corbel, Sylvain; Mougin, Christian; Martin-Laurent, Fabrice; Crouzet, Olivier; Bru, David; Nélieu, Sylvie; Bouaïcha, Noureddine

    2015-06-01

    The impact of a crude extract of Microcystis aeruginosa (PCC7820) containing 14 microcystin variants was investigated on seeds germination and radicles development of four agricultural plants: two tomato varieties Solanum lycopersicum (MicroTom and Saint-Pierre), the wheat Triticum aestivum and the lettuce Lactuca sativa. In addition, the effect of 14 d-exposure to irrigation water containing realistic concentrations of microcystins (0-0.1 mg eq. microcystin-LRL(-1)) on the tomato MicroTom seedling growth was further evaluated on roots and aerial part biomasses. Impacts on soil bacterial parameters, as such extracellular enzymatic activities, nitrification activity and abundances of ammonia-oxidizing microorganisms were also investigated. In germination-test, the cyanobacterial extract inhibited only the germination of the wheat seeds, with an EC50 of 11 mg eq. microcystin-LRL(-1); which is 13 times lower than that of the cadmium chloride (EC50 of 145 mg L(-1)). Moreover, the cyanobacterial extract containing low concentrations of microcystins increased the growth of primary roots; however, high concentrations decreased it for all plants except for the wheat. In the soil-plant approach, only aerial part biomass of the tomato MicroTom was enhanced significantly. In addition, only soil nitrification potential and ammonia-oxidizing bacterial abundances were consistently impacted. A significant positive correlation (r=0.56) was found between the increase of nitrification potential and abundances of ammonia-oxidizing bacteria. This work suggested, that exposure to a cyanobacterial extract containing realistic environmental microcystins concentrations could affect seed germination, depending plant species. It was also highlighted, for the first time, disturbances in soil bacteria functioning, evidences on soil nitrification process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Production of a broad specificity antibody for the development and validation of an optical SPR screening method for free and intracellular microcystins and nodularin in cyanobacteria cultures.

    Science.gov (United States)

    Devlin, Shauna; Meneely, Julie P; Greer, Brett; Campbell, Katrina; Vasconcelos, Vitor; Elliott, Christopher T

    2014-05-01

    A highly sensitive broad specificity monoclonal antibody was produced and characterised for microcystin detection through the development of a rapid surface plasmon resonance (SPR) optical biosensor based immunoassay. The antibody displayed the following cross-reactivity: MC-LR 100%; MC-RR 108%; MC-YR 68%; MC-LA 69%; MC-LW 71%; MC-LF 68%; and Nodularin 94%. Microcystin-LR was covalently attached to a CM5 chip and with the monoclonal antibody was employed in a competitive 4 min injection assay to detect total microcystins in water samples below the WHO recommended limit (1 µg/L). A 'total microcystin' level was determined by measuring free and intracellular concentrations in cyanobacterial culture samples as this toxin is an endotoxin. Glass bead beating was used to lyse the cells as a rapid extraction procedure. This method was validated according to European Commission Decision 96/23/EC criteria. The method was proven to measure intracellular microcystin levels, the main source of the toxin, which often goes undetected by other analytical procedures and is advantageous in that it can be used for the monitoring of blooms to provide an early warning of toxicity. It was shown to be repeatable and reproducible, with recoveries from spiked samples ranging from 74 to 123%, and had % CVs below 10% for intra-assay analysis and 15% for inter-assay analysis. The detection capability of the assay was calculated as 0.5 ng/mL for extracellular toxins and 0.05 ng/mL for intracellular microcystins. A comparison of the SPR method with LC-MS/MS was achieved by testing six Microcystis aeruginosa cultures and this study yielded a correlation R(2) value of 0.9989. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Co-occurrence of non-toxic (cyanopeptolin) and toxic (microcystin) peptides in a bloom of Microcystis sp. from a Chilean lake.

    Science.gov (United States)

    Neumann, U; Campos, V; Cantarero, S; Urrutia, H; Heinze, R; Weckesser, J; Erhard, M

    2000-06-01

    A cyanobacterial bloom occurring in 1998 in lake Tres Pascualas (Concepción/Chile) was found to be dominated by Microcystis sp. The bloom contained both non-toxic (cyanopeptolin-type) and hepatotoxic (microcystin-type) peptides. Cyanopeptolin structure of the non-toxic peptides (called cyanopeptolin VW-1 and VW-2, respectively) was revealed by matrix assisted laser desorption ionization mass spectrometry (MALDI-TOF-MS) of whole cells, showing dominant molecular ions at m/z = 975 and m/z 995, respectively. On post source decay (PSD), both cyanopeptolins showed fragments deriving from Ahp-Phe-MTyr (3-amino-6-hydroxy-2-piperidone), the characteristic partial structure of cyanopeptolins. The amounts of each of the two cyanopeptolins could only roughly be estimated to be >0.1% of bloom material dry weight. In addition the blooms contained microcystins (20 microg/g bloom dry weight as determined by RP-HPLC, 13 microg/g according to ELISA determination). MALDI-TOF-MS revealed several structural variants of microcystin: MCYST-RR (microcystin with Arg and Arg, indicated by m/z 1,038 and confirmed by PSD revealing a m/z = 135 fragment deriving from the Adda side chain, MCYST-FR (microcystin with Phe and Arg, indicated by m/z = 1,015). The presence of [Asp(3)]-MCYST-LR (microcystin with Leu and Arg, Asp non-methylated, indicated by m/z 981), and [Asp(3)]-MCYST-YR (microcystin with Tyr and Arg, Asp non-methylated, indicated by m/z 1,031) were likely. The relative amounts of the peptides varied between February, April, and May. Whole cell extracts from the bloom material revealed specific enzyme inhibitory activities. The serin-proteases trypsin, plasmin, elastase were inhibited, assumable due to the cyanopeptolins found. Elastase and the cysteine-protease papain were not inhibited, inhibitions of protein kinase and glutathione S-transferase (GST) were low. Strong inhibition was observed with protein-phosphatase-1, likely due to the microcystins present in the samples.

  11. Microcystin distribution in physical size class separations of natural plankton communities

    Science.gov (United States)

    Graham, J.L.; Jones, J.R.

    2007-01-01

    Phytoplankton communities in 30 northern Missouri and Iowa lakes were physically separated into 5 size classes (>100 ??m, 53-100 ??m, 35-53 ??m, 10-35 ??m, 1-10 ??m) during 15-21 August 2004 to determine the distribution of microcystin (MC) in size fractionated lake samples and assess how net collections influence estimates of MC concentration. MC was detected in whole water (total) from 83% of takes sampled, and total MC values ranged from 0.1-7.0 ??g/L (mean = 0.8 ??g/L). On average, MC in the > 100 ??m size class comprised ???40% of total MC, while other individual size classes contributed 9-20% to total MC. MC values decreased with size class and were significantly greater in the >100 ??m size class (mean = 0.5 ??g /L) than the 35-53 ??m (mean = 0.1 ??g/L), 10-35 ??m (mean = 0.0 ??g/L), and 1-10 ??m (mean = 0.0 ??g/L) size classes (p sieves allowed detection of MC at low levels (???0.01 ??/L); 93% of lakes had detectable levels of MC in concentrated samples. Thus, small mesh plankton nets are an option for documenting MC occurrence, but whole water samples should be collected to characterize total MC concentrations. ?? Copyright by the North American Lake Management Society 2007.

  12. Sorption, degradation and mobility of microcystins in Chinese agriculture soils: risk assessment for groundwater protection

    Energy Technology Data Exchange (ETDEWEB)

    Chen Wei [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu Nanlu No 7, Wuhan 430072 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Song Lirong [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu Nanlu No 7, Wuhan 430072 (China)]. E-mail: lrsong@ihb.ac.cn; Gan Nanqin [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu Nanlu No 7, Wuhan 430072 (China); Li Lin [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu Nanlu No 7, Wuhan 430072 (China)

    2006-12-15

    In the present paper, sorption, persistence, and leaching behavior of three microcystin variants in Chinese agriculture soils were examined. Based on this study, the values of capacity factor and slope for three MCs variants in three soils ranged from 0.69 to 6.00, and 1.01 to 1.54, respectively. The adsorption of MCs in the soils decreased in the following order: RR>Dha{sup 7} LR>LR. Furthermore, for each MC variant in the three soils, the adsorption rate in the soils decreased in the following order: soil A>soil C>soil B. The calculated half-time ranged between 7.9 and 17.8 days for MC-RR, 6.0-17.1 days for MC-LR, and 7.1-10.2 days for MC-Dha{sup 7} LR. Results from leaching experiments demonstrated that recoveries of toxins in leachates ranged from 0-16.7% for RR, 73.2-88.9% for LR, and 8.9-73.1% for Dha{sup 7} LR. The GUS value ranged from 1.48 to 2.06 for RR, 1.82-2.88 for LR, and 1.76-2.09 for Dha{sup 7} LR. Results demonstrated the use of cyanobacterial collections as plant fertilizer is likely to be unsafe in soils. - The use of cyanobacterial blooms as plant fertilizer is likely to be unsafe in soils.

  13. Presence of the Cyanotoxin Microcystin in Arctic Lakes of Southwestern Greenland

    Directory of Open Access Journals (Sweden)

    Jessica V. Trout-Haney

    2016-08-01

    Full Text Available Cyanobacteria and their toxins have received significant attention in eutrophic temperate and tropical systems where conspicuous blooms of certain planktonic taxa release toxins into fresh water, threatening its potability and safe use for recreation. Although toxigenic cyanobacteria are not confined to high nutrient environments, bloom-forming species, or planktonic taxa, these other situations are studied les often studied. For example, toxin production in picoplankton and benthic cyanobacteria—the predominant photoautotrophs found in polar lakes—is poorly understood. We quantified the occurrence of microcystin (MC, a hepatotoxic cyanotoxin across 18 Arctic lakes in southwestern Greenland. All of the focal lakes contained detectable levels of MC, with concentrations ranging from 5 ng·L−1 to >400 ng·L−1 during summer, 2013–2015. These concentrations are orders of magnitude lower than many eutrophic systems, yet the median lake MC concentration in Greenland (57 ng·L−1 was still 6.5 times higher than the median summer MC toxicity observed across 50 New Hampshire lakes between 1998 and 2008 (8.7 ng·L−1. The presence of cyanotoxins in these Greenlandic lakes demonstrates that high latitude lakes can support toxigenic cyanobacteria, and suggests that we may be underestimating the potential for these systems to develop high levels of cyanotoxins in the future.

  14. Okadaic acid and microcystin insensitive PPP-family phosphatases may represent novel biotechnology targets.

    Science.gov (United States)

    Uhrig, R Glen; Moorhead, Greg B

    2011-12-01

    Reversible protein phosphorylation is of central importance to the proper cellular functioning of all living organisms. Catalyzed by the opposing reactions of protein kinases and phosphatases, dysfunction in reversible protein phosphorylation can result in a wide variety of cellular aberrations. In eukaryotic organisms there exists four classes of protein phosphatases, of which the PPP-family protein phosphatases have documented susceptibility to a range of protein and small molecule inhibitors. These inhibitors have been of great importance to the biochemical characterization of PPP-family protein phosphatases since their discovery, but also maintain in natura biological significance with their endogenous regulatory properties (protein inhibitors) and toxicity (small molecule inhibitors). Recently, two unique PPP-family protein phosphatases, named the Shewanella-like protein phosphatases (SLP phosphatases), from Arabidopsis thaliana were characterized and found to be phylogenetically similar to the PPP-family protein phosphatases protein phosphatase 1 (PP1) and protein phosphatase 2A (PP2A), while completely lacking sensitivity to the classic PPP-family phosphatase small molecule inhibitors okadaic acid and microcystin-LR. SLP phosphatases were also found to be absent in metazoans, but present in a wide range of bacteria, fungi and protozoa responsible for human disease. The unique biochemical properties and evolutionary heritage of SLP phosphatases suggests they could not only be potential biotechnology targets for agriculture, but may also prove to be of interest for future therapeutic drug development. © 2011 Landes Bioscience

  15. Survey of microcystins in water between 1995 and 1996 in Paraná, Brazil using ELISA.

    Science.gov (United States)

    Hirooka, E Y; Pinotti, M H; Tsutsumi, T; Yoshida, F; Ueno, Y

    1999-01-01

    An enzyme-linked immunosorbent assay (ELISA) based on a monoclonal antibody was used to determine microcystin (MC) concentrations in water supplies and water plant samples collected between November 1995 and October 1996, from five regions of Paraná, Brazil. In addition, the presence of Microcystis sp. was monitored. Of the 50 samples obtained, 12 were from an urban lake, 8 from human water supplies, 10 from recreational lakes, 13 from farm waters used for animal pasture and 7 from aquaculture facilities. M. aeruginosa was positive in all locations. MCs were positive (>50 pg ml(-1)) in 9 samples (2 samples from human water supplies, 5 from recreational lakes and 2 from animal pasture). Heavy contamination with MCs was observed in water samples collected in May 1996 from 2 recreation (swimming-fishing sites at Itaipu dam, 6380 and 10,000 pg ml(-1)) and human supplies (6627 pg ml(-1)) samples. At these sites, a large bloom of Microcystis sp. was detected. Treatment with 1 ppm Cl- reduced MCs levels, although 267 pg ml(-1) remained in the water plant samples. Our data showed frequent occurrence of Microcystis sp., which may be a hazard to humans and animals in the state of Paraná. More detailed investigations are required to evaluate the risk of natural MC contamination in the water supplied in this region.

  16. Roles of miRNAs in microcystin-LR-induced Sertoli cell toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yuan [Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093 (China); Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093 (China); Wang, Hui [The Centre for Individualized Medication, Linköping University Hospital, Linköping University, Linköping SE-58185 (Sweden); Wang, Cong [Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093 (China); Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093 (China); Qiu, Xuefeng [Department of Urology, Affiliated Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing 210008 (China); Benson, Mikael [The Centre for Individualized Medication, Linköping University Hospital, Linköping University, Linköping SE-58185 (Sweden); Yin, Xiaoqin [Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093 (China); Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093 (China); Xiang, Zou [Department of Microbiology and Immunology, Mucosal Immunobiology and Vaccine Research Center, Institute of Biomedicine, University of Gothenburg, Gothenburg (Sweden); Li, Dongmei, E-mail: lidm@nju.edu.cn [Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093 (China); Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093 (China); and others

    2015-08-15

    Microcystin (MC)-LR, a cyclic heptapeptide, is a potent reproductive system toxin. To understand the molecular mechanisms of MC-induced reproductive system cytotoxicity, we evaluated global changes of miRNA and mRNA expression in mouse Sertoli cells following MC-LR treatment. Our results revealed that the exposure to MC-LR resulted in an altered miRNA expression profile that might be responsible for the modulation of mRNA expression. Bio-functional analysis indicated that the altered genes were involved in specific cellular processes, including cell death and proliferation. Target gene analysis suggested that junction injury in Sertoli cells exposed to MC-LR might be mediated by miRNAs through the regulation of the Sertoli cell-Sertoli cell pathway. Collectively, these findings may enhance our understanding on the modes of action of MC-LR on mouse Sertoli cells as well as the molecular mechanisms underlying the toxicity of MC-LR on the male reproductive system. - Highlights: • miRNAs were altered in Sertoli cells exposed to MC-LR. • Alerted genes were involved in different cell functions including the cell morphology. • MC-LR adversely affected Sertoli cell junction formation through the regulating miRNAs.

  17. Nitrogen forms influence microcystin concentration and composition via changes in cyanobacterial community structure.

    Directory of Open Access Journals (Sweden)

    Marie-Eve Monchamp

    Full Text Available The eutrophication of freshwaters is a global health concern as lakes with excess nutrients are often subject to toxic cyanobacterial blooms. Although phosphorus is considered the main element regulating cyanobacterial biomass, nitrogen (N concentration and more specifically the availability of different N forms may influence the overall toxicity of blooms. In this study of three eutrophic lakes prone to cyanobacterial blooms, we examined the effects of nitrogen species and concentrations and other environmental factors in influencing cyanobacterial community structure, microcystin (MC concentrations and MC congener composition. The identification of specific MC congeners was of particular interest as they vary widely in toxicity. Different nitrogen forms appeared to influence cyanobacterial community structure leading to corresponding effects on MC concentrations and composition. Total MC concentrations across the lakes were largely explained by a combination of abiotic factors: dissolved organic nitrogen, water temperature and ammonium, but Microcystis spp. biomass was overall the best predictor of MC concentrations. Environmental factors did not appear to affect MC congener composition directly but there were significant associations between specific MC congeners and particular species. Based on redundancy analyses (RDA, the relative biomass of Microcystis aeruginosa was associated with MC-RR, M. wesenbergii with MC-LA and Aphanizomenon flos-aquae with MC-YR. The latter two species are not generally considered capable of MC production. Total nitrogen, water temperature, ammonium and dissolved organic nitrogen influenced the cyanobacterial community structure, which in turn resulted in differences in the dominant MC congener and the overall toxicity.

  18. Subacute microcystin-LR exposure alters the metabolism of thyroid hormones in juvenile zebrafish (Danio Rerio).

    Science.gov (United States)

    Liu, Zidong; Tang, Rong; Li, Dapeng; Hu, Qing; Wang, Ying

    2015-01-30

    Microcystin-LR (MC-LR) has been detected extensively in the aquatic environment and has the potential to disturb the thyroid endocrine system. However, limited information is available on the effects of subacute MC-LR exposure on fish thyroid hormone (TH) metabolism. In the present study, juvenile zebrafish (Danio rerio) were exposed to MC-LR at environmentally relevant concentrations (0, 1, 5, and 25 μg/L) for 28 days. Whole-body TH content and thyroid follicle histology were used as direct endpoints to assess thyroid disruption. The activities of iodothyronine deiodinases (IDs) and the transcription of selected genes associated with TH synthesis were also investigated to study the underlying mechanisms of endocrine disruption. Exposure of zebrafish to MC-LR significantly increased whole-body thyroxine (T4) content but decreased whole-body triiodothyronine (T3) content. We also observed hypertrophy and hyperplasia of the thyroid follicle epithelial cells, as well as up-regulation of corticotropin-releasing hormone (CRH), thyroid-stimulating hormone (TSH), thyroid peroxidase (TPO), and transthyretin (TTR) genes. The decreases in ID1 and ID2 activities coupled with an increase in ID3 activity were observed in MC-LR treatment groups. These results demonstrate that exposure to MC-LR at environmental concentrations results in the disturbance of TH homeostasis by disrupting the synthesis and conversion of THs.

  19. Subacute Microcystin-LR Exposure Alters the Metabolism of Thyroid Hormones in Juvenile Zebrafish (Danio Rerio

    Directory of Open Access Journals (Sweden)

    Zidong Liu

    2015-01-01

    Full Text Available Microcystin-LR (MC-LR has been detected extensively in the aquatic environment and has the potential to disturb the thyroid endocrine system. However, limited information is available on the effects of subacute MC-LR exposure on fish thyroid hormone (TH metabolism. In the present study, juvenile zebrafish (Danio rerio were exposed to MC-LR at environmentally relevant concentrations (0, 1, 5, and 25 μg/L for 28 days. Whole-body TH content and thyroid follicle histology were used as direct endpoints to assess thyroid disruption. The activities of iodothyronine deiodinases (IDs and the transcription of selected genes associated with TH synthesis were also investigated to study the underlying mechanisms of endocrine disruption. Exposure of zebrafish to MC-LR significantly increased whole-body thyroxine (T4 content but decreased whole-body triiodothyronine (T3 content. We also observed hypertrophy and hyperplasia of the thyroid follicle epithelial cells, as well as up-regulation of corticotropin-releasing hormone (CRH, thyroid-stimulating hormone (TSH, thyroid peroxidase (TPO, and transthyretin (TTR genes. The decreases in ID1 and ID2 activities coupled with an increase in ID3 activity were observed in MC-LR treatment groups. These results demonstrate that exposure to MC-LR at environmental concentrations results in the disturbance of TH homeostasis by disrupting the synthesis and conversion of THs.

  20. Freshwater algae competition and correlation between their growth and microcystin production.

    Science.gov (United States)

    Álvarez, Xana; Valero, Enrique; Cancela, Ángeles; Sánchez, Ángel

    2016-11-01

    There are some different freshwater algae in Eutrophic reservoirs which bloom with specific environmental conditions, and some of them are cyanobacteria. In this investigation, we have cultivated microalgae present in natural water samples from a eutrophic reservoir. Variations in temperature and light were evaluated, as well as the competition among different green algae and cyanobacteria. There were three different freshwater algae growing together, Scenedesmus sp., Kirchneriella sp. and Microcystis aeruginosa, this cyanobacterium was the algae that reached the highest development and growth during the culture. While the algae grew, the concentration of toxin (microcystin-LR) increased until it reached the highest levels at 570 μg g -1 . Blooms occurred at temperatures of 28 ± 1.5 °C and light cycles of longer hours of light than dark. This took place during the summer months, from June to September (in the study area). At temperatures below 18 °C, algae did not grow. Blooms were reproduced to a laboratory scale in different conditions in order to understand the development of freshwater algae, as well as to help decision-making about water supply from that reservoir.

  1. Benthic cyanobacteria: A source of cylindrospermopsin and microcystin in Australian drinking water reservoirs.

    Science.gov (United States)

    Gaget, Virginie; Humpage, Andrew R; Huang, Qiong; Monis, Paul; Brookes, Justin D

    2017-11-01

    Cyanobacteria represent a health hazard worldwide due to their production of a range of highly potent toxins in diverse aquatic environments. While planktonic species have been the subject of many investigations in terms of risk assessment, little is known about benthic forms and their impact on water quality or human and animal health. This study aimed to purify isolates from environmental benthic biofilms sampled from three different drinking water reservoirs and to assess their toxin production by using the following methods: Enzyme-Linked Immunosorbent Assay (ELISA), High-Performance Liquid Chromatography (HPLC), Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) and quantitative PCR (qPCR). Microscopic observation of the isolates allowed the identification of various filamentous cyanobacterial genera: Anabaena (benthic form), Calothrix and Nostoc from the Nostocales and Geitlerinema, Leptolyngbya, Limnothrix, Lyngbya, Oxynema, Phormidium and Pseudanabaena representing non-heterocystous filamentous cyanobacteria. The Phormidium ambiguum strain AWQC-PHO021 was found to produce 739 ng/mg of dry weight (d/w) of cylindrospermopsin and 107 ng/mg (d/w) of deoxy-cylindrospermopsin. The Nostoc linckia strain AWQC-NOS001 produced 400 ng/mg (d/w) of a microcystin analogue. This is the first report of hepatotoxin production by benthic cyanobacteria in temperate Australian drinking water reservoirs. These findings indicate that water quality monitoring programs need to consider benthic cyanobacteria as a potential source of toxins. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Apoptotic responses of zebrafish (Danio rerio) after exposure with microcystin-LR under different ambient temperatures.

    Science.gov (United States)

    Ji, Wei; Liang, Hualei; Zhou, Wenshan; Zhang, Xuezhen

    2013-08-01

    Microcystins (MCs) can cause evident hepatic apoptosis. In vitro studies indicated that uptake of MC by isolated hepatocytes was dramatically reduced as ambient temperature dropped, and some studies presented a hypothesis that differences in core body temperatures in animals result in diverse uptake of MC, as well as different toxic effects. Thus far, however, few in vivo studies have been conducted to investigate the effects of temperature on MC-induced hepatocyte apoptosis in fish, a typical poikilotherm. In the present study, zebrafish were treated with MC-LR, an MC metabolite, at three water temperatures (12, 22 and 32 °C), and evident differences in apoptotic profiles were observed. Damage to liver ultrastructures revealed temperature-dependent early-stage patterns of apoptosis. Flow-cytometric analysis indicated that hepatocyte apoptotic rates varied with a temperature-dependent effect. The transcription levels of some apoptosis-related genes were determined using quantitative real-time polymerase chain reaction, and significantly elevated gene expressions of P53, Bcl-2, Bax and caspase-3 were found in the 12 and 32 °C groups. Results of the present study indicate that different ambient temperatures can lead to various toxic effects of MCs on hepatic apoptosis in fish. Copyright © 2012 John Wiley & Sons, Ltd.

  3. Salt and cadmium stress tolerance caused by overexpression of the Glycine Max Na+/H+ Antiporter (GmNHX1) gene in duckweed (Lemna turionifera 5511).

    Science.gov (United States)

    Yang, Lin; Han, Yujie; Wu, Di; Yong, Wang; Liu, Miaomiao; Wang, Sutong; Liu, Wenxin; Lu, Meiyi; Wei, Ying; Sun, Jinsheng

    2017-11-01

    Cadmium (Cd) pollution has aroused increasing attention due to its toxicity. It has been proved that Na + /H + Antiporter (NHX1) encodes a well-documented protein in Na + /H + trafficking, which leads to salt tolerance. This study showed that Glycine max Na + /H + Antiporter (GmNHX1) improved short-term cadmium and salt resistance in Lemna turionifera 5511. Expression of GmNHX1 prevented root from abscission and cell membrane damage, which also can enhance antioxidant system, inhibited of reactive oxygen species (ROS) accumulation and cause a less absorption of Cd under cadmium and salt stress. The cadmium tolerance suggested that NHX1 was involved under the cadmium stress. Copyright © 2017. Published by Elsevier B.V.

  4. Degradation and detoxification of microcystin-LR in drinking water by sequential use of UV and ozone.

    Science.gov (United States)

    Liu, Xiaowei; Chen, Zhonglin; Zhou, Nan; Shen, Jimin; Ye, Miaomiao

    2010-01-01

    Microcystins (MCs) produced by cyanobacteria are strong hepatotoxins and classified as possible carcinogens. MCs pose a considerable threat to human health through tainted drinking and surface waters. Herein filtrated water from a waterworks in Harbin, China, was spiked with microcystin-LR (MC-LR) extracted from a toxic scum of microcystis aeruginosa, and the spiked sample waters were treated using UV irradiation with consequent ozonation process (UV/O3), compared with ozonation at a dose range commonly applied in water treatment plants, UV irradiation at 254 nm and UV irradiation combined with ozonation (UV+O3), respectively. The remaining of toxins were analyzed using high-performance liquid chromatography and also determined using a protein phosphatase type 2A inhibition assay, which was utilized to evaluate the reduction in toxicity. Results indicated that in comparison to other three processes (O3, UV, and UV+O3), UV/O3 process could effectively decrease both the concentration and toxicity of MC-LR at 100 microg/L level after 5 min UV irradiation with consequent 5 min ozonation at 0.2 mg/L (below 1 microg/L), while 0.5 mg/L ozone dose was required for the level below 0.1 microg/L. The addition of an UV treatment step to the existing treatment train may induce significant transformation of micropollutants and breaks down the natural organic matters into moieties unfavorable for ozone decomposition, stabilizing the ozone residual. These findings suggested that sequential use of UV and ozone may be a suitable method for the removal of these potentially hazardous microcystins from drinking water.

  5. Microcystin-LR Induces Apoptosis via NF-κB /iNOS Pathway in INS-1 Cells

    Directory of Open Access Journals (Sweden)

    Kai Shen

    2011-07-01

    Full Text Available Cyanobacterial toxins, especially the microcystins, are found in eutrophied waters throughout the world, and their potential to impact on human and animal health is a cause for concern. Microcystin-LR (MC-LR is one of the common toxic microcystin congeners and occurs frequently in diverse water systems. Recent work suggested that apoptosis plays a major role in the toxic effects induced by MC-LR in hepatocytes. However, the roles of MC-LR in pancreatic beta cells have not been fully established. The aim of the present study was to assess possible in vitro effects of MC-LR on cell apoptosis in the rat insulinoma cell line, INS-1. Our results demonstrated that MC-LR promoted selectively activation of NF-κB (increasing nuclear p50/p65 translocation and increased the mRNA and protein levels of induced nitric oxide synthase (iNOS. The chronic treatment with MC-LR stimulated nitric oxide (NO production derived from iNOS and induced apoptosis in a dose dependent manner in INS-1 cells. Meanwhile, this effect was inhibited by the NF-κB inhibitor PDTC, which reversed the apoptosis induced by MC-LR. Our observations indicate that MC-LR induced cell apoptosis via an iNOS-dependent pathway. A well-known nuclear transcription factor, NF-κB, is activated and mediates intracellular nitric oxide synthesis. We suggest that the apoptosis induced by chronic MC-LR in vivo presents a possible cause of β-cell dysfunction, as a key environmental factor in the development of diabetes mellitus.

  6. Characteristics of competitive uptake between Microcystin-LR and natural organic matter (NOM) fractions using strongly basic anion exchange resins.

    Science.gov (United States)

    Dixit, Fuhar; Barbeau, Benoit; Mohseni, Madjid

    2018-03-29

    Microcystins are the most commonly occurring cyanotoxins, and have been extensively studied across the globe. In the present study, a strongly basic anion exchange resin was employed to investigate the removal of Microcystin-LR (MCLR), one of the most toxic microcystin variants. Factors influencing the uptake behavior included the MCLR and resin concentrations, resin dosage, and natural organic matter (NOM) characteristics, specifically, the charge density and molecular weight distribution of source water NOM. Equivalent background concentration (EBC) was employed to evaluate the competitive uptake between NOM and MCLR. The experimental data were compared with different mathematical and physical models and pore diffusion was determined as the rate-limiting step. The resin dose/solute concentration ratio played a key role in the MCLR uptake process and MCLR removal was attributed primarily to electrostatic attractions. Charge density and molecular weight distribution of the background NOM fractions played a major role in MCLR removal at lower resin dosages (200 mg/L ∼ 1 mL/L and below), where a competitive uptake was observed due to the limited exchange sites. Further, evidences of pore blockage and site reduction were also observed in the presence of humics and larger molecular weight organic fractions, where a four-fold reduction in the MCLR uptake was observed. Comparable results were obtained for laboratory studies on synthetic laboratory water and surface water under similar conditions. Given their excellent performance and low cost, anion exchange resins are expected to present promising potentials for applications involving the removal of removal of algal toxins and NOM from surface waters. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Determination of cyanobacteria toxins (microcystins): current situation; Problematica y situacion actual de la determinacion de toxinas de cianobacterias: microcistinas

    Energy Technology Data Exchange (ETDEWEB)

    Moreno Navarro, I. M.; Pichardo Sanchez, S.; Carmean Fernandez, A. M. [Universidad de Sevilla (Spain)

    2003-07-01

    A review of the different biological and chemical methods developed to determine cyano bacterial toxins, microcystins (MC), in freshwater has been carried out. However, any of them have been accepted as a standard method by the official environmental agencies. Biological methods as the mouse bioassays, immunoassays or protein phosphatase, inhibition assays are used as screening methods to detect MC. Analytical methods as High Performance Liquid Chromatography (HPLC) or Capillary Electrophoresis (CE), with different detectors, allow to identify and quantify the individual toxins produced by different cyano bacterial species. (Author) 40 refs.

  8. IDENTIFICATION OF MICROCYSTIN TOXINS FROM A STRAIN OF MICROCYSTIS AERUGINOSA BY LIQUID CHROMATOGRAPHY INTRODUCTION INTO A HYBRID LINEAR ION TRAP-FOURIER TRANSFORM ION CYCLOTRON RESONANCE MASS SPECTROMETER

    Science.gov (United States)

    The cyclic heptapeptide microcystin toxins produced by a strain of Microcystis aeruginosa that has not been investigated previously were separated by liquid chromatography and identified by high-accuracy m/z measurements of their [M + H]+ ions and the fragment i...

  9. LC/MS/MS structure elucidation of reaction intermediates formed during the TiO2 photocatalysis of microcystin-LR

    Science.gov (United States)

    Microcystin-LR (MC-LR), a cyanotoxin and emerging drinking water contaminant, was treated with TiO(2) photocatalysts immobilized on stainless steel plates as an alternative to nanoparticles in slurry. The reaction intermediates of MC-LR were identified with mass spectrometry (MS)...

  10. Microcystin-LR removal from aqueous solutions using a magnetically separable N-doped TiO2 nanocomposite under visible light irradiation

    Science.gov (United States)

    The performance of magnetically separable N-doped TiO2 was found to be significantly improved when compared with a non-magnetic N-doped TiO2 for the aqueous removal of cyanotoxin Microcystin-LR. The observed enhanced photocatalytic activity may be related to the presence of ferri...

  11. METHOD 544. DETERMINATION OF MICROCYSTINS AND NODULARIN IN DRINKING WATER BY SOLID PHASE EXTRACTION AND LIQUID CHROMATOGRAPHY/TANDEM MASS SPECTROMETRY (LC/MS/MS)

    Science.gov (United States)

    Method 544 is an accurate and precise analytical method to determine six microcystins (including MC-LR) and nodularin in drinking water using solid phase extraction and liquid chromatography tandem mass spectrometry (SPE-LC/MS/MS). The advantage of this SPE-LC/MS/MS is its sensi...

  12. Co-Occurrence of Microcystins and Taste-and-Odor Compounds in Drinking Water Source and Their Removal in a Full-Scale Drinking Water Treatment Plant

    Science.gov (United States)

    Feng, Muhua; Xu, Xiangen; Liu, Feifei; Ke, Fan; Li, Wenchao

    2018-01-01

    The co-occurrence of cyanotoxins and taste-and-odor compounds are a growing concern for drinking water treatment plants (DWTPs) suffering cyanobacteria in water resources. The dissolved and cell-bound forms of three microcystin (MC) congeners (MC-LR, MC-RR and MC-YR) and four taste-and-odor compounds (geosmin, 2-methyl isoborneol, β-cyclocitral and β-ionone) were investigated monthly from August 2011 to July 2012 in the eastern drinking water source of Lake Chaohu. The total concentrations of microcystins and taste-and-odor compounds reached 8.86 μg/L and 250.7 ng/L, respectively. The seasonal trends of microcystins were not consistent with those of the taste-and-odor compounds, which were accompanied by dominant species Microcystis and Dolichospermum. The fate of the cyanobacteria and metabolites were determined simultaneously after the processes of coagulation/flocculation, sedimentation, filtration and chlorination in the associated full-scale DWTP. The dissolved fractions with elevated concentrations were detected after some steps and the breakthrough of cyanobacteria and metabolites were even observed in finished water. Chlorophyll-a limits at intake were established for the drinking water source based on our investigation of multiple metabolites, seasonal variations and their elimination rates in the DWTP. Not only microcystins but also taste-and-odor compounds should be taken into account to guide the management in source water and in DWTPs. PMID:29301296

  13. DNA aptamer selection and aptamer-based fluorometric displacement assay for the hepatotoxin microcystin-RR

    International Nuclear Information System (INIS)

    Wu, Shijia; Li, Qi; Duan, Nuo; Wang, Zhouping; Ma, Haile

    2016-01-01

    Microcystin-RR (MC-RR) is a highly acute hepatotoxin produced by cyanobacteria. It is harmful to both humans and the environment. A novel aptamer was identified by the systemic evolution of ligands by exponential enrichment (SELEX) method as a recognition element for determination of MC-RR in aquatic products. The graphene oxide (GO) SELEX strategy was adopted to generate aptamers with high affinity and specificity. Of the 50 aptamer candidates tested, sequence RR-33 was found to display high affinity and selectivity, with a dissociation constant of 45.7 ± 6.8 nM. Aptamer RR-33 therefore was used as the recognition element in a fluorometric assay that proceeds as follows: (1) Biotinylated aptamer RR-33 is immobilized on the streptavidinylated wells of a microtiterplate, and carboxyfluorescein (FAM) labelled complementary DNA is then allowed to hybridize. (2) After removal of excess (unbound) cDNA, sample containing MC-RR is added and incubated at 37 °C for 2 h. (3) Displaced free cDNA is washed away and fluorescence intensity measured at excitation/emission wavelengths of 490/515 nm. The calibration plot is linear in the 0.20 to 2.5 ng·mL −1 concentration range, and the limit of detection is 80 pg·mL −1 . The results indicate that the GO-SELEX technology is appropriate for the screening of aptamers against small-molecule toxins. The detection scheme was applied to the determination of MC-RR in (spiked) water, mussel and fish and gave recoveries between 91 and 98 %. The method compares favorably to a known ELISA. Conceivably, this kind of assay is applicable to other toxins for which appropriate aptamers are available. (author)

  14. Excretion pattern and dynamics of glutathione detoxification of microcystins in Sprague Dawley rat.

    Science.gov (United States)

    Li, Wei; He, Jun; Chen, Jun; Xie, Ping

    2018-01-01

    The excretion route and dynamics of the glutathione (GSH) conjugate of microcystin-RR (MCRR), MCRR-GSH, were quantitatively studied in Sprague Dawley rat exposed with MCRR-GSH via liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS). In the MCRR-GSH-treated rat, the average MCRR-Cysteine (MCRR-Cys)/MCRR-GSH ratio reached as high as 105.3, which indicated that the intermediate conjugate MCRR-GSH was rapidly converted to the product compound MCRR-Cys. Besides, MCRR was consistently detected in MCRR-GSH-treated rat, which suggested that MCRR can be dissociated from the MCRR-GSH conjugate and the reversibility of the MC-GSH conjugate. Results of total MC contents analysis in excrement showed that the total MC contents in urine were significantly higher than those in feces. The ratio of the total MC content in urine to feces was as high as 129.3, which demonstrates that the urine is the main route of excretion after MCRR-GSH-treatment. In urine, the MCRR-Cys concentration was 27.8-fold, 19.4-fold higher than MCRR-GSH and MCRR, respectively. Our results, for the first time, quantitatively found that MCRR-GSH was rapidly converted to MCRR-Cys after exposed to rat, and was excreted mainly through urine in the form of the MCRR-Cys conjugate. This study suggests that the GSH detoxification pathway of MCs could help to explain the greater sensitivity of mammals to MCs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Adsorption of microcystin-LR on mesoporous carbons and its potential use in drinking water source.

    Science.gov (United States)

    Park, Jeong-Ann; Jung, Sung-Mok; Yi, In-Geol; Choi, Jae-Woo; Kim, Song-Bae; Lee, Sang-Hyup

    2017-06-01

    Microcystin-LR (MC-LR) is a common toxin derived from cyanobacterial blooms an effective, rapid and non-toxic method needs to be developed for its removal from drinking water treatment plants (DWTP). For an adsorption-based method, mesoporous carbon can be a promising supplemental adsorbent. The effect of mesoporous carbon (MC1, MC2, and MC3) properties and water quality parameters on the adsorption of MC-LR were investigated and the results were analyzed by kinetic, isotherm, thermodynamic, Derjaguin-Landau-Verwey-Overbeek (DLVO), and intraparticle diffusion models. MC1 was the most appropriate type for the removal of MC-LR with a maximum adsorption capacity of 35,670.49 μg/g. Adsorption of MC-LR is a spontaneous reaction dominated by van der Waals interactions. Pore sizes of 8.5-14 nm enhance the pore diffusion of MC-LR from the surface to the mesopores of MC1. The adsorption capacity was not sensitive to changes in the pH (3.2-8.0) and the existence of organic matter (2-5 mg/L). Furthermore, the final concentration of MC-LR was below the WHO guideline level after a 10-min reaction with 20 mg/L of MC1 in the Nak-Dong River, a drinking water source. The MC-LR adsorption mainly competed with humic substances (500-1000 g/mole); however, they did not have a great effect on adsorption. Copyright © 2017. Published by Elsevier Ltd.

  16. Experimental models of microcystin accumulation in Daphnia magna grazing on Planktothrix rubescens: implications for water management.

    Science.gov (United States)

    Shams, Shiva; Cerasino, Leonardo; Salmaso, Nico; Dietrich, Daniel R

    2014-03-01

    In this study, we investigated the kinetic aspects of the microcystin (MC) transfer from Planktothrix rubescens to Daphnia magna by carrying out exposure experiments in small simple mesocosms. We hypothesized that higher fractions of toxic cyanobacteria in the diet of grazers would shift the balance towards a greater than linear, i.e. non-linear accumulation of MC in D. magna. This hypothesis was tested by exposing D. magna to varying initial densities of MC-producing P. rubescens. The evolving models of MC accumulation differed largely as a result of the duration of exposure and initial MC concentrations used. Within the first 24h of exposure, MC accumulation in D. magna was linear, irrespective of the initial densities of toxic P. rubescens and thus MC concentrations. After 48 h of exposure, MC accumulation in D. magna showed an exponential pattern, possibly due to a delayed digestion of P. rubescens and/or decreased MC detoxification capabilities when compared with higher ambient concentrations of MC. After 72 h toxin concentrations in Daphnia drop in all experiments as a consequence of the reduced cyanobacterial cells in the medium and the detoxification of MC within Daphnia. The results obtained suggest that in lakes with higher MC content and longer cyanobacterial bloom period MC accumulation in D. magna should be more pronounced than in mesotrophic lakes with lower MC content. The latter interpretation, however, should be verified investigating accumulation of MC both in larger mesocosms and in situ, in lakes of different trophic status. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Cadmium toxicity to Microcystis aeruginosa PCC 7806 and its microcystin-lacking mutant.

    Directory of Open Access Journals (Sweden)

    Bin Huang

    Full Text Available The adverse effects of microcystin (MC produced by cyanobacteria have drawn considerable attention from the public. Yet it remains unclear whether MC confers any benefits to the cyanobacteria themselves. One suggested function of MC is complexation, which may influence the bioaccumulation and toxicity of trace metals. To test this hypothesis, we examined Cd toxicity to wild-type Microcystis aeruginosa PCC 7806 (WT and its MC-lacking mutant (MT under nutrient-enriched (+NP, phosphorus-limited (-P, and nitrogen-limited (-N conditions. The accumulation of Cd and the biochemical parameters associated with its detoxification [total phosphorus (TP, inorganic polyphosphate (Poly-P, and glutathione (GSH in the cells as well as intra- and extra-cellular carbohydrates] were quantified. Although the -P cyanobacteria accumulated less Cd than their +NP and -N counterparts, the different nutrient-conditioned cyanobacteria were similarly inhibited by similar free ion concentration of Cd in the medium ([Cd2+]F. Such good toxicity predictability of [Cd2+]F was ascribed to the synchronous decrease in the intracellular concentrations of Cd and TP. Nevertheless, Cd toxicity was still determined by the intracellular Cd to phosphorus ratio (Cd/P, in accordance with what has been reported in the literature. On the other hand, the concentrations of TP, Poly-P, and carbohydrates went up, but GSH concentration dropped down with the enhancement of [Cd2+]F, indicating their association with Cd detoxification. Although the inactivation of MC peptide synthetase gene had some nutrient and Cd concentration dependent effects on the parameters above, both cyanobacterial strains showed the same Cd accumulation ability and displayed similar Cd sensitivity. These results suggest that MC cannot affect metal toxicity either by regulating metal accumulation or by altering the detoxification ability of the cyanobacteria. Other possible functions of MC need to be further investigated.

  18. Intracellular Calcium Plays a Critical Role in the Microcystin-LR-Elicited Neurotoxicity Through PLC/IP3 Pathway.

    Science.gov (United States)

    Cai, Fei; Liu, Jue; Li, Cairong; Wang, Jianghua

    2015-01-01

    Neurotoxicity of microcystin-leucine-arginine (MCLR) has been widely reported. However, the mechanism is not fully understood. Using primary hippocampal neurons, we tested the hypothesis that MCLR-triggered activation in intracellular free calcium concentration ([Ca(2+)](i)) induces the death of neurons. Microcystin-leucine-arginine inhibited cell viability at a range of 0.1 to 30 μmol/L and caused a dose-dependent increase in [Ca(2+)](i). This increase in [Ca(2+)](i) was observed in Ca(2+)-free media and blocked by an endoplasmic reticulum Ca(2+) pump inhibitor, suggesting intracellular Ca(2+) release. Moreover, pretreatment of hippocampal neurons with intracellular Ca(2+) chelator (O,O'-bis (2-aminophenyl) ethyleneglycol-N,N,N',N'-tetraacetic acid, tetraacetoxy-methyl ester) and inositol 1,4,5-trisphosphate receptor antagonist (2-aminoethoxydiphenyl borate) could block both the Ca(2+) mobilization and the neuronal death following MCLR exposure. In contrast, the ryanodine receptor inhibitor (dantrolene) did not ameliorate the effect of MCLR. In conclusion, MCLR disrupts [Ca(2+)](i) homeostasis in neurons by releasing Ca(2+) from intracellular stores, and this increase in [Ca(2+)](i) may be a key determinant in the mechanism underlying MCLR-induced neurotoxicity. © The Author(s) 2015.

  19. Acute Exposure to Microcystin-Producing Cyanobacterium Microcystis aeruginosa Alters Adult Zebrafish (Danio rerio Swimming Performance Parameters

    Directory of Open Access Journals (Sweden)

    Luiza Wilges Kist

    2011-01-01

    Full Text Available Microcystins (MCs are toxins produced by cyanobacteria (blue-green algae, primarily Microcystis aeruginosa, forming water blooms worldwide. When an organism is exposed to environmental perturbations, alterations in normal behavioral patterns occur. Behavioral repertoire represents the consequence of a diversity of physiological and biochemical alterations. In this study, we assessed behavioral patterns and whole-body cortisol levels of adult zebrafish (Danio rerio exposed to cell culture of the microcystin-producing cyanobacterium M. aeruginosa (MC-LR, strain RST9501. MC-LR exposure (100 μg/L decreased by 63% the distance traveled and increased threefold the immobility time when compared to the control group. Interestingly, no significant alterations in the number of line crossings were found at the same MC-LR concentration and time of exposure. When animals were exposed to 50 and 100 μg/L, MC-LR promoted a significant increase (around 93% in the time spent in the bottom portion of the tank, suggesting an anxiogenic effect. The results also showed that none of the MC-LR concentrations tested promoted significant alterations in absolute turn angle, path efficiency, social behavior, or whole-body cortisol level. These findings indicate that behavior is susceptible to MC-LR exposure and provide evidence for a better understanding of the ecological consequences of toxic algal blooms.

  20. Effects of microcystin and complex cyanobacterial samples on growth and oxidative stress paramaters in green alga Pseudokirchneriella subcapitata and comparison with the effects of model oxidative stressor, herbicide paraquat

    Czech Academy of Sciences Publication Activity Database

    Bártová, Kateřina; Hilscherová, Klára; Babica, Pavel; Maršálek, Blahoslav; Bláha, Luděk

    2011-01-01

    Roč. 26, č. 6 (2011), s. 641-648 ISSN 1520-4081 Institutional research plan: CEZ:AV0Z60050516 Keywords : microcystin * paraquat * oxidative stress Subject RIV: EF - Botanics Impact factor: 2.407, year: 2011

  1. Adsorption and photodegradation of microcystin-LR onto sediments collected from reservoirs and rivers in Taiwan: a laboratory study to investigate the fate, transfer, and degradation of microcystin-LR.

    Science.gov (United States)

    Munusamy, Thirumavalavan; Hu, Ya-Lan; Lee, Jiunn-Fwu

    2012-07-01

    This study demonstrated the adsorption capacity of microcystin-LR (MC-LR) onto sediment samples collected from different reservoirs (Emerald and Jade reservoirs) and rivers (Dongshan, Erhjen, and Wukai rivers) in Taiwan to investigate the fate, transport behavior, and photodegradation of MC-LR. Langmuir adsorption and photodegradation studies were carried out in the laboratory and tested the capability of sediments for MC-LR adsorption. These data suggested that sediments play a crucial role in microcystins degradation in aquatic systems. The results of batch experiments revealed that the adsorption of MC-LR varied significantly with texture, pH, and organic matter content of sediments. Silty and clay textures of the samples were associated with larger content of organic matter, and they displayed the enhanced MC-LR adsorption. Low pH sediment showed increased adsorption of MC-LR. The effective photodegradation of MC-LR (1.6 μg/mL) was achieved within 60 min under 254 nm light irradiation. A comparative study of adsorption capacity of all sediment samples was carried out and discussed with respect to different aspects. Among all, sediments collected from Jade reservoir showed enhanced MC-LR adsorption (11.86 μg/g) due to favored textural properties (BET surface area = 20.24 m2/g and pore volume = 80.70 nm). These data provide important information that may be applied to management strategies for improvement of water quality in reservoirs and rivers and other water bodies in Taiwan.

  2. Dose-dependent effects of extracted microcystins on embryonic development, larval growth and histopathological changes of southern catfish (Silurus meridionalis).

    Science.gov (United States)

    Zhang, Xuezhen; Xie, Ping; Wang, Weimin; Li, Dapeng; Li, Li; Tang, Rong; Lei, Hehua; Shi, Zechao

    2008-03-01

    A laboratory toxic experiment was conducted to examine dose-dependent effects of extracted microcystins (MCs) on embryonic development, larval growth and histopathological changes of southern catfish (Silurus meridionalis). Fertilized eggs were incubated in solutions with four concentrations of MCs (0, 1, 10, 100 microg MC-L Req l(-1)). Higher MCs retarded egg development (2-10h delays) and larval growth, reduced hatching rate (up to 45%), and caused high malformation rate (up to 15%) and hepatocytes damage (characterized by disorganization of cell structure and a loss of adherence between hepatocytes, cellular degeneration with vacuolar hepatocytes and marginal nuclei, even hepatocellular necrosis). A 10 microg MC-L Req l(-1) is close to a high concentration in natural cyanobacterial blooms, suggesting a possible existence of such toxic effects in eutrophic waters.

  3. Effects of different algaecides on the photosynthetic capacity, cell integrity and microcystin-LR release of Microcystis aeruginosa

    International Nuclear Information System (INIS)

    Zhou, Shiqing; Shao, Yisheng; Gao, Naiyun; Deng, Yang; Qiao, Junlian; Ou, Huase; Deng, Jing

    2013-01-01

    Bench scale tests were conducted to study the effects of four common algaecides, including copper sulfate, hydrogen peroxide, diuron and ethyl 2-methylacetoacetate (EMA) on the photosynthetic capacity, cell integrity and microcystin-LR (MC-LR) release of Microcystis aeruginosa. The release of potassium (K + ) from cell membrane during algaecide exposure was also analyzed. The three typical photosynthetic parameters, including the effective quantum yield (φ e ), photosynthetic efficiency (α) and maximal electron transport rate (rETR max ), were measured by a pulse amplitude modulated (PAM) fluorometry. Results showed that the photosynthetic capacity was all inhibited by the four algaecides, to different degrees, by limiting the energy capture in photosynthesis, and blocking the electron transfer chain in primary reaction. For example, at high diuron concentration (7.5 mg L −1 ), φ e , α and rETR max decreased from 0.46 to 0.19 (p −2 s −1 /μmol photons m −2 s −1 , and from 160.7 to 0.1 (p −2 s −1 compared with the control group after 96 h of exposure, respectively. Furthermore, the increase of algaecide dose could lead to the cell lysis, as well as release of intracellular MC-LR that enhanced the accumulation of extracellular MC-LR. The order of MC-LR release potential for the four algaecides was CuSO 4 > H 2 O 2 > diuron > EMA. Highlights: • PAM was used to investigate the effects of algaecides on Microcystis aeruginosa. • We estimate the release of potassium (K + ) from cell membrane for cell lysis. • The risk of microcystin-LR release was evaluated after algaecides exposure. • The order of MC-LR release potential was copper sulfate > hydrogen peroxide > diuron > ethyl 2-methylacetoacetate

  4. Characteristics of UV-MicroO3 Reactor and Its Application to Microcystins Degradation during Surface Water Treatment

    Directory of Open Access Journals (Sweden)

    Guangcan Zhu

    2015-01-01

    Full Text Available The UV-ozone (UV-O3 process is not widely applied in wastewater and potable water treatment partly for the relatively high cost since complicated UV radiation and ozone generating systems are utilized. The UV-microozone (UV-microO3, a new advanced process that can solve the abovementioned problems, was introduced in this study. The effects of air flux, air pressure, and air humidity on generation and concentration of O3 in UV-microO3 reactor were investigated. The utilization of this UV-microO3 reactor in microcystins (MCs degradation was also carried out. Experimental results indicated that the optimum air flux in the reactor equipped with 37 mm diameter quartz tube was determined to be 18∼25 L/h for efficient O3 generation. The air pressure and humidity in UV-microO3 reactor should be low enough in order to get optimum O3 output. Moreover, microcystin-RR, YR, and LR (MC-RR, MC-YR, and MC-LR could be degraded effectively by UV-microO3 process. The degradation of different MCs was characterized by first-order reaction kinetics. The pseudofirst-order kinetic constants for MC-RR, MC-YR, and MC-LR degradation were 0.0093, 0.0215, and 0.0286 min−1, respectively. Glucose had no influence on MC degradation through UV-microO3. The UV-microO3 process is hence recommended as a suitable advanced treatment method for dissolved MCs degradation.

  5. Microcystin-LR induced reactive oxygen species mediate cytoskeletal disruption and apoptosis of hepatocytes in Cyprinus carpio L.

    Directory of Open Access Journals (Sweden)

    Jinlin Jiang

    Full Text Available Microcystins (MCs are a group of cyclic hepatotoxic peptides produced by cyanobacteria. Microcystin-LR (MC-LR contains Leucine (L and Arginine (R in the variable positions, and is one of the most common and potently toxic peptides. MC-LR can inhibit protein phosphatase type 1 and type 2A (PP1 and PP2A activities and induce excessive production of reactive oxygen species (ROS. The underlying mechanism of the inhibition of PP1 and PP2A has been extensively studied. The over-production of ROS is considered to be another main mechanism behind MC-LR toxicity; however, the detailed toxicological mechanism involved in over-production of ROS in carp (Cyprinus carpio L. remains largely unclear. In our present study, the hydroxyl radical (•OH was significantly induced in the liver of carp after a relatively short-term exposure to MC-LR. The elevated reactive oxygen species (ROS production may play an important role in the disruption of microtubule structure. Pre-injection of the antioxidant N-acetyl-cysteine (NAC provided significant protection to the cytoskeleton, however buthionine sulfoximine (BSO exacerbated cytoskeletal destruction. In addition, the elevated ROS formation induced the expression of apoptosis-related genes, including p38, JNKa, and bcl-2. A significant increase in apoptotic cells was observed at 12-48 hours. Our study further supports evidence that ROS are involved in MC-LR induced damage to liver cells in carp, and indicates the need for further study of the molecular mechanisms behind MC-LR toxicity.

  6. Combined effects of elevated CO{sub 2} and Cd-contaminated water on growth, photosynthetic response, Cd accumulation and thiolic components status in Lemna minor L

    Energy Technology Data Exchange (ETDEWEB)

    Pietrini, F.; Bianconi, D.; Massacci, A. [Institute of Agro-Environmental and Forest Biology, National Research Council of Italy, Via Salaria Km 29,300, 00015 Monterotondo Scalo, Roma (Italy); Iannelli, M.A., E-mail: adelaide.iannelli@ibba.cnr.it [Institute of Agricultural Biology and Biotechnology, National Research Council of Italy, Via Salaria Km 29,300, 00015 Monterotondo Scalo, Roma (Italy)

    2016-05-15

    Highlights: • Elevated CO{sub 2} did not affect the ability of L. minor plants to accumulate Cd in their tissues. • Elevated CO{sub 2} decreased Cd toxicity in L. minor plants by increasing photosynthesis. • Elevated CO{sub 2} reduced Cd toxicity in duckweed by enhancing antioxidant system. - Abstract: The objective of this study was to investigate the combined effects of elevated CO{sub 2} and cadmium (Cd) treatments on growth, photosynthetic efficiency and phytoremediation ability in Lemna minor L. Plants of L. minor were exposed to different Cd concentrations (0, 1.5, 2.5 and 5 mg L{sup −1} Cd) for periods of 24, 48 and 72 h at ambient (AC) and at elevated (EC) CO{sub 2} (350 and 700 ppm, respectively). Cadmium concentration, bioconcentration factor, enzyme activities and thiols content enhanced in plants with the increase of Cd treatments, time of exposure and at both CO{sub 2} levels. Glutathione levels increased only at AC. Growth, photosynthetic and chlorophyll fluorescence parameters, and the reduced glutathione to oxidized glutathione ratio declined in plants with increasing exposure time, Cd treatments and at both CO{sub 2} levels. Our results suggested that the alleviation of toxicity, at low Cd doses, observed in L. minor grown at EC is dependent on both increased photosynthesis and an enhanced antioxidant capacity.

  7. Response of Lemna minor L. to short-term cobalt exposure: The effect on photosynthetic electron transport chain and induction of oxidative damage

    Energy Technology Data Exchange (ETDEWEB)

    Begović, Lidija, E-mail: lbegovic@biologija.unios.hr [Josip Juraj Strossmayer University of Osijek, Department of Biology, Ulica cara Hadrijana 8/A, H R -31000 Osijek (Croatia); Mlinarić, Selma, E-mail: smlinaric@biologija.unios.hr [Josip Juraj Strossmayer University of Osijek, Department of Biology, Ulica cara Hadrijana 8/A, H R -31000 Osijek (Croatia); Antunović Dunić, Jasenka, E-mail: jantunovic@biologija.unios.hr [Josip Juraj Strossmayer University of Osijek, Department of Biology, Ulica cara Hadrijana 8/A, H R -31000 Osijek (Croatia); Katanić, Zorana, E-mail: zkatanic@biologija.unios.hr [Josip Juraj Strossmayer University of Osijek, Department of Biology, Ulica cara Hadrijana 8/A, H R -31000 Osijek (Croatia); Lončarić, Zdenko, E-mail: zdenko.loncaric@pfos.hr [Faculty of Agriculture, Josip Juraj Strossmayer University of Osijek, Ulica kralja Petra Svačića 1d, H R -31000 Osijek (Croatia); Lepeduš, Hrvoje, E-mail: hlepedus@yahoo.com [Faculty of Humanities and Social Sciences, Josip Juraj Strossmayer University of Osijek, Lorenza Jägera 9, HR-31000 Osijek (Croatia); Cesar, Vera, E-mail: vcesarus@yahoo.com [Josip Juraj Strossmayer University of Osijek, Department of Biology, Ulica cara Hadrijana 8/A, H R -31000 Osijek (Croatia)

    2016-06-15

    Highlights: • Cobalt (Co{sup 2+}) impaired the function of oxygen evolving complex (OEC) in L. minor L. • Electron transport through PSII components varied depending on Co{sup 2+} concentration. • K-band was proven to be suitable parameter for investigation of Co{sup 2+} toxicity. • Increased lipid peroxidation level showed early oxidative damage induced by Co{sup 2+}. - Abstract: The effect of two concentrations of cobalt (Co{sup 2+}) on photosynthetic activity and antioxidative response in Lemna minor L. were assessed 24, 48 and 72 h after the start of the exposure. Higher concentration of cobalt (1 mM) induced growth inhibition while lower concentration (0.01 mM) increased photosynthetic pigments content. Analysis of chlorophyll a fluorescence transients revealed high sensitivity of photosystem II primary photochemistry to excess of Co{sup 2+} especially at the higher concentration where decreased electron transport beyond primary quinone acceptor Q{sub A}{sup −} and impaired function of oxygen evolving complex (OEC) was observed. Due to impairment of OEC, oxygen production was decreased at higher Co{sup 2+} concentration. Activity of superoxide dismutase was mainly inhibited while lipid peroxidation increased, at both concentrations, indicating that cobalt-induced oxidative damage after short exposure and moreover, susceptibility of the membranes in the cell to cobalt toxicity. Results obtained in this study suggest possible application of used parameters as tools in assessment of early damage caused by metals.

  8. Microbial Detoxification of Deoxynivalenol (DON), Assessed via a Lemna minor L. Bioassay, through Biotransformation to 3-epi-DON and 3-epi-DOM-1.

    Science.gov (United States)

    Vanhoutte, Ilse; De Mets, Laura; De Boevre, Marthe; Uka, Valdet; Di Mavungu, José Diana; De Saeger, Sarah; De Gelder, Leen; Audenaert, Kris

    2017-02-13

    Mycotoxins are toxic metabolites produced by fungi. To mitigate mycotoxins in food or feed, biotransformation is an emerging technology in which microorganisms degrade toxins into non-toxic metabolites. To monitor deoxynivalenol (DON) biotransformation, analytical tools such as ELISA and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) are typically used. However, these techniques do not give a decisive answer about the remaining toxicity of possible biotransformation products. Hence, a bioassay using Lemna minor L. was developed. A dose-response analysis revealed significant inhibition in the growth of L. minor exposed to DON concentrations of 0.25 mg/L and higher. Concentrations above 1 mg/L were lethal for the plant. This bioassay is far more sensitive than previously described systems. The bioassay was implemented to screen microbial enrichment cultures, originating from rumen fluid, soil, digestate and activated sludge, on their biotransformation and detoxification capability of DON. The enrichment cultures originating from soil and activated sludge were capable of detoxifying and degrading 5 and 50 mg/L DON. In addition, the metabolites 3-epi-DON and the epimer of de-epoxy-DON (3-epi-DOM-1) were found as biotransformation products of both consortia. Our work provides a new valuable tool to screen microbial cultures for their detoxification capacity.

  9. A Nanopore-Structured Nitrogen-Doped Biocarbon Electrocatalyst for Oxygen Reduction from Two-Step Carbonization of Lemna minor Biomass

    Science.gov (United States)

    Guo, Chaozhong; Li, Zhongbin; Niu, Lidan; Liao, Wenli; Sun, Lingtao; Wen, Bixia; Nie, Yunqing; Cheng, Jing; Chen, Changguo

    2016-05-01

    So far, the development of highly active and stable carbon-based electrocatalysts for oxygen reduction reaction (ORR) to replace commercial Pt/C catalyst is a hot topic. In this study, a new nanoporous nitrogen-doped carbon material was facilely designed by two-step pyrolysis of the renewable Lemna minor enriched in crude protein under a nitrogen atmosphere. Electrochemical measurements show that the onset potential for ORR on this carbon material is around 0.93 V (versus reversible hydrogen electrode), slightly lower than that on the Pt/C catalyst, but its cycling stability is higher compared to the Pt/C catalyst in an alkaline medium. Besides, the ORR at this catalyst approaches to a four-electron transfer pathway. The obtained ORR performance can be basically attributed to the formation of high contents of pyridinic and graphitic nitrogen atoms inside this catalyst. Thus, this work opens up the path in the ORR catalysis for the design of nitrogen-doped carbon materials utilizing aquatic plants as starting precursors.

  10. ACCUMULATION OF RECOMBINANT FUSION PROTEIN – SECRETORY ANALOG OF Ag85B AND ESAT6 MYCOBACTERIUM TUBERCULOSIS PROTEINS – IN TRANSGENIC Lemna minor L. PLANTS

    Directory of Open Access Journals (Sweden)

    A.A.Peterson

    2015-10-01

    Full Text Available Determination of the presence of the recombinant fusion protein (ESAT6-Ag85B(ΔTMD-6His and its accumulation level in duckweed plants (Lemna minor L. was the aim of the research. ESAT6 and Ag85B are secretory proteins of Mycobacterium tuberculosis and are considered as potential candidates for development of new vaccine against tuberculosis (TB. Transgenic duckweed plants were obtained previously by Agrobacterium rhizogenes-mediated transformation and possessed fusion gene sequence esxA-fbpBΔTMD. Specific polyclonal antibodies were produced in immunized mice to identify levels of accumulation of TB antigens in plants. Recombinant antigen used for mice immunization was obtained in our laboratory by expression in E. coli. Western blot analysis revealed the recombinant tuberculosis antigen ESAT6-Ag85B(ΔTMD-6His in extracts from transgenic L. minor plants. The level of accumulation of the protein corresponds to 0.4-0.5 µg protein per 1 g of fresh weight of plant. Additionally, the accumulation of recombinant protein was investigated in lyophilized transgenic plants after 1.5 year storage. Duckweed plants accumulating a recombinant analogue of M. tuberculosis secretory proteins can be used for development of plant-based edible vaccines.

  11. Biodiversity and Importance of Floating Weeds of Dara Ismail, Khan ...

    African Journals Online (AJOL)

    These plants include Bryophytes: 1 species, Ricciocarpus natans (L.) Corda; Pteridophytes: 2 species, Azolla pinnata R.Br. and Marselia quadrifolia L., and Spermatophytes: 8 species, Lemna aequinoctialis Welw., L. gibba L., Marselia quadrifoliata L. Nelumbo nucifera Gaerth., Nymphoides cristata (Roxb.) O. Ketze.

  12. Experimental analysis of the competition between algae and duckweed

    NARCIS (Netherlands)

    Roijackers, R.M.M.; Szabo, S.; Scheffer, M.

    2004-01-01

    We performed indoor competition experiments between algae and Lemna gibba L. in order to unravel mechanisms of competition. To separate effects of shading and physical interference from nutrient competition we grew the two groups physically separated while sharing the same water. A multifactorial

  13. The strength of limiting factors for duckweed during algal competition

    NARCIS (Netherlands)

    Szabo, S.; Roijackers, R.M.M.; Scheffer, M.; Borics, G.

    2005-01-01

    Duckweed (Lemna gibba) growth was found to be strongly reduced by unicellular green algae (Scenedesmus conspicua, Chlorella sp., Chlamydomonas sp.) in indoor experiments. These algae reduced N, P, Fe and Mn concentrations of the medium drastically, moreover they increased the pH beyond 10.

  14. Increased risk of exposure to microcystins in the scum of the filamentous cyanobacterium Aphanizomenon flos-aquae accumulated on the western shoreline of the Curonian Lagoon.

    Science.gov (United States)

    Šulčius, Sigitas; Pilkaitytė, Renata; Mazur-Marzec, Hanna; Kasperovičienė, Jūratė; Ezhova, Elena; Błaszczyk, Agata; Paškauskas, Ričardas

    2015-10-15

    Concentration of toxic cyanobacteria blooms on the downwind shore of high recreational amenity water bodies with largely increases the risk of exposure to cyanotoxins. In this study analysis of phytoplankton structure, cyanotoxin composition and concentration was performed on cyanobacteria scum material, high- and low-density bloom samples in the Curonian Lagoon. We found that the concentration of cyanotoxins in the scum material increased from ∼30 to ∼300-fold compared to bloom samples. In Microcystis aeruginosa dominated samples microcystin-LR was present at the highest concentration, while the dominance of Planktothrix agardhii was associated with the occurrence of dmMC-RR as the major microcystin variant. The toxicological potential of cyanobacterial scums in the Curonian Lagoon is emphasized, and management by removal of these scums is proposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Computational study of the covalent bonding of microcystins to cysteine residues--a reaction involved in the inhibition of the PPP family of protein phosphatases.

    Science.gov (United States)

    Pereira, Susana R; Vasconcelos, Vítor M; Antunes, Agostinho

    2013-01-01

    Microcystins (MCs) are cyclic peptides, produced by cyanobacteria, that are hepatotoxic to mammals. The toxicity mechanism involves the potent inhibition of protein phosphatases, as the toxins bind the catalytic subunits of five enzymes of the phosphoprotein phosphatase (PPP) family of serine/threonine-specific phosphatases: Ppp1 (aka PP1), Ppp2 (aka PP2A), Ppp4, Ppp5 and Ppp6. The interaction with the proteins includes the formation of a covalent bond with a cysteine residue. Although this reaction seems to be accessory for the inhibition of PPP enzymes, it has been suggested to play an important part in the biological role of MCs and furthermore is involved in their nonenzymatic conjugation to glutathione. In this study, the molecular interaction of microcystins with their targeted PPP catalytic subunits is reviewed, including the relevance of the covalent bond for overall inhibition. The chemical reaction that leads to the formation of the covalent bond was evaluated in silico, both thermodynamically and kinetically, using quantum mechanical-based methods. As a result, it was confirmed to be a Michael-type addition, with simultaneous abstraction of the thiol hydrogen by a water molecule, transfer of hydrogen from the water to the α,β-unsaturated carbonyl group of the microcystin and addition of the sulfur to the β-carbon of the microcystin moiety. The calculated kinetics are in agreement with previous experimental results that had indicated the reaction to occur in a second step after a fast noncovalent interaction that inhibited the enzymes per se. © 2011 The Authors Journal compilation © 2011 FEBS.

  16. Effect of glucose in removal of microcystin-LR by viable commercial probiotic strains and strains isolated from dadih fermented milk.

    Science.gov (United States)

    Nybom, Sonja M K; Collado, M Carmen; Surono, Ingrid S; Salminen, Seppo J; Meriluoto, Jussi A O

    2008-05-28

    The removal of the cyanobacterial peptide toxin microcystin-LR at 4 and 37 degrees C by six commercial probiotic strains and Lactobacillus plantarum strains IS-10506 and IS-20506 isolated from dadih, Indonesian traditional fermented milk, was assessed in this study. The aim was to evaluate the main factors influencing the viability and metabolic activity of the probiotic strains, as well as their capacity to remove microcystin-LR. Both L. plantarum strains isolated from dadih, as well as Bifidobacterium lactis strains Bb12 and 420, were shown to be more resistant, and >85% remained viable in phosphate-buffered saline (PBS) solution for 48 h of incubation at either temperature, while the viability of the other four commercial bacteria decreased markedly over time. The effect of glucose on viability and removal of toxin was shown to be a strain-specific and strain-dependent property, but in general, the efficiency of microcystin-LR removal increased when glucose was added to the solution. A maximum removal of 95% was observed for L. plantarum strain IS-20506 (37 degrees C, 10 (11) colony-forming units mL(-1)) with 1-2% glucose supplementation and 75% in PBS alone.

  17. Fitorremediación mediante el uso de dos especies vegetales Lemna minor (Lenteja de agua), y Eichornia crassipes (Jacinto de agua) en aguas residuales producto de la actividad minera

    OpenAIRE

    Jaramillo Jumbo, Mariuxi Del Cisne; Flores Campoverde, Edison Darío

    2012-01-01

    La contaminación del agua con metales pesados es un problema de gran importancia, aunque existen varios métodos convencionales para su remoción estos son muy costosos por lo que la fitorremediación es una alternativa que utiliza plantas para reducir la concentración de dichos contaminantes. En este trabajo se determinó la capacidad de absorción del mercurio mediante el uso de las macrófitas acuáticas Eichornia crassipes y Lemna minor en diferentes condiciones experimentales. A las macrófit...

  18. Relations between DNA- and RNA-based molecular methods for cyanobacteria and microcystin concentration at Maumee Bay State Park Lakeside Beach, Oregon, Ohio, 2012

    Science.gov (United States)

    Stelzer, Erin A.; Loftin, Keith A.; Struffolino, Pamela

    2013-01-01

    Water samples were collected from Maumee Bay State Park Lakeside Beach, Oregon, Ohio, during the 2012 recreational season and analyzed for selected cyanobacteria gene sequences by DNA-based quantitative polymerase chain reaction (qPCR) and RNA-based quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Results from the four DNA assays (for quantifying total cyanobacteria, total Microcystis, and Microcystis and Planktothrix strains that possess the microcystin synthetase E (mcyE) gene) and two RNA assays (for quantifying Microcystis and Planktothrix genera that are expressing the microcystin synthetase E (mcyE) gene) were compared to microcystin concentration results determined by an enzyme-linked immunosorbent assay (ELISA). Concentrations of the target in replicate analyses were log10 transformed. The average value of differences in log10 concentrations for the replicates that had at least one detection were found to range from 0.05 to >0.37 copy per 100 milliliters (copy/100 mL) for DNA-based methods and from >0.04 to >0.17 copy/100 mL for RNA-based methods. RNA has a shorter half-life than DNA; consequently, a 24-hour holding-time study was done to determine the effects of holding time on RNA concentrations. Holding-time comparisons for the RNA-based Microcystis toxin mcyE assay showed reductions in the number of copies per 100 milliliters over 24 hours. The log difference between time 2 hours and time 24 hours was >0.37 copy/100 mL, which was higher than the analytical variability (log difference of >0.17 copy/100 mL). Spearman’s correlation analysis indicated that microcystin toxin concentrations were moderately to highly related to DNA-based assay results for total cyanobacteria (rho=0.69), total Microcystis (rho=0.74), and Microcystis strains that possess the mcyE gene (rho=0.81). Microcystin toxin concentrations were strongly related with RNA-based assay results for Microcystis mcyE gene expression (rho=0.95). Correlation analysis could

  19. Assessment of Lemna minor (duckweed) and Corbicula fluminea (freshwater clam) as potential indicators of contaminated aquatic ecosystems: responses to presence of psychoactive drug mixtures.

    Science.gov (United States)

    Mohamed, Bourioug; Jean-Yves, Mazzitelli; Pierre, Marty; Hélène, Budzinski; Aleya, Lotfi; Elsa, Bonnafé; Florence, Geret

    2017-01-31

    The pharmaceutical products are emerging pollutants continuously released into the environment, because they cannot be effectively removed by the wastewater treatment plants. In recent years, questions have been raised concerning the environmental risks related to these pollutants. The goal of this research was to evaluate the responses in Lemna minor after 7 days and in Corbicula fluminea after differing durations (1, 3, 7, and 19 days) of exposure to the psychoactive drug mixture (valproic acid, citalopram, carbamazepine, cyamemazine, hydroxyzine, oxazepam, norfluoxetine, lorazepam, fluoxetine, and sertraline) in different concentrations (0, 0 + ethanol, drug concentration (DC) 1 = river water concentration, DC2 = effluent concentration, and DC3 = 10× effluent concentration). In this aim, growth parameters of L. minor, gluthathione S-transferase (GSTs), catalase (CAT), ethoxyresorufin-O-deethylase (EROD) and/or gene expressions (pi-gst, cat, cytochrome P450 4 (cyp4), multidrug resistant 1 (mdr1), and superoxide dismutase (sod)) were measured. GST activities increased significantly in L. minor exposed to DC3, but no changes were found in CAT activity. In C. fluminea, EROD activity was induced significantly in both gill and digestive gland tissues after 3 days' exposure to DC3, while a GST increase was observed only in digestive gland tissues, suggesting that these pharmaceuticals induced an oxidative effect. Gene expression analysis revealed transient transcriptomic responses of cyp4, sod, and mdr1 under drug concentrations 2 or 3 and no change of expression for the other genes (cat and pi-gst) or condition (environmental drug concentration) tested. Finally, the data reported in this study represent important ecotoxicological information, confirming that this enzyme family (cyp4, sod, and mdr1) may be considered as a sensible and early indicator of exposure to drugs and emphasizing the involvement of selected genes in detoxification pathways.

  20. Effect of zinc and lead on the physiological and biochemical properties of aquatic plant Lemna minor: its potential role in phytoremediation

    Science.gov (United States)

    Jayasri, M. A.; Suthindhiran, K.

    2017-06-01

    Plants have gained importance in situ bioremediation of heavy metals. In the present study, different concentrations of zinc (Zn2+) (0.5, 5, 10, 15, 20 mg/l) and lead (Pb2+) (1, 2, 4, 6, 8 mg/l) were used to evaluate metal tolerance level of Lemna minor. L.minor were exposed to metals for 4 days and tested for its dry to fresh weight ratio (DW/FW), photosynthetic pigments production and protein content. The oxidative damage was detected by measuring catalase activity. L.minor showed tolerance against Zn2+ and Pb2+ at a concentration of 10 and 4 mg/l, respectively. Among the metals, Pb2+ showed a significant toxicity at 8 mg/l. High concentration (20 mg/l of Zn2+ and 8 mg/l of Pb2+) of the metals displayed a considerable negative effect on soluble proteins (13 fold decrease with Zn2+ and 4 fold decrease with Pb2+) and photosynthetic pigments (twofold decrease with Zn2+ and onefold decrease with Pb2+) and lead to a consequent reduction in number of fronds. Further, the catalase was greatly increased (twofold decrease with Zn2+ and sixfold decrease with Pb2+) under metal stress. The results indicate that L.minor withstands Zn2+ and Pb2+ toxicity up to the concentration of 10 and 4 mg/l, respectively. Hence, the metal tolerant property of this plant shall be exploited for bioremediation of Zinc and Lead in polluted water. Further, the detailed and wide range of heavy metal toxicity studies should be done to reveal the possible use of this plant on large scale bioremediation purpose.

  1. Toxicidade aguda e risco ambiental do antibiótico oxitetraciclina para tilápia ( Oreochromis niloticus , Daphnia magna e Lemna minor

    Directory of Open Access Journals (Sweden)

    A.A. Machado

    Full Text Available RESUMO O objetivo deste estudo foi classificar o antibiótico Terramicina(r de acordo com a toxicidade aguda e o risco de intoxicação ambiental para Oreochromis niloticus, Daphnia magna e Lemna minor, com base no seu ingrediente ativo oxitetraciclina (OTC. Além disso, observou-se a ocorrência de sinais de intoxicação aguda em peixes e o efeito da diluição do antibiótico sobre as variáveis de qualidade de água. Alevinos, neonatos e frondes foram expostos a concentrações de OTC. De acordo com os resultados dos testes de toxicidade aguda, a Terramicina(r foi classificada pela toxicidade aguda e pelo risco de intoxicação ambiental. Para O. niloticus, a CL(I50; 48h calculada foi de 6,92 mg L-1, para D. magna a CE(I50; 48h foi de 0,17mg.L-1, enquanto para L. minor a CI(I50;7d foi de 0,68 mg L-1. A Terramicina(r foi classificada como muito tóxica para O. niloticus e extremamente tóxica para D. magna e L. minor e causa risco de intoxicação ambiental para os três organismos testados. Concentrações de 7,5 e 8,0 mg L-1 de OTC reduziram a concentração de oxigênio dissolvido na água. De acordo com este estudo, a Terramicina(r não deve ser utilizada na aquicultura, pois é altamente tóxica e causa risco de intoxicação ambiental aos organismos teste.

  2. Effects of different algaecides on the photosynthetic capacity, cell integrity and microcystin-LR release of Microcystis aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Shiqing [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Shao, Yisheng, E-mail: yishengshao@163.com [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); China Academy of Urban Planning and Design, Beijing 100037 (China); Gao, Naiyun [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Deng, Yang [Department of Earth and Environmental Studies, Montclair State University, Montclair NJ 07043 (United States); Qiao, Junlian; Ou, Huase; Deng, Jing [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China)

    2013-10-01

    Bench scale tests were conducted to study the effects of four common algaecides, including copper sulfate, hydrogen peroxide, diuron and ethyl 2-methylacetoacetate (EMA) on the photosynthetic capacity, cell integrity and microcystin-LR (MC-LR) release of Microcystis aeruginosa. The release of potassium (K{sup +}) from cell membrane during algaecide exposure was also analyzed. The three typical photosynthetic parameters, including the effective quantum yield (φ{sub e}), photosynthetic efficiency (α) and maximal electron transport rate (rETR{sub max}), were measured by a pulse amplitude modulated (PAM) fluorometry. Results showed that the photosynthetic capacity was all inhibited by the four algaecides, to different degrees, by limiting the energy capture in photosynthesis, and blocking the electron transfer chain in primary reaction. For example, at high diuron concentration (7.5 mg L{sup −1}), φ{sub e}, α and rETR{sub max} decreased from 0.46 to 0.19 (p < 0.01), from 0.20 to 0.01 (p < 0.01) μmol electrons m{sup −2} s{sup −1}/μmol photons m{sup −2} s{sup −1}, and from 160.7 to 0.1 (p < 0.001) μmol m{sup −2} s{sup −1} compared with the control group after 96 h of exposure, respectively. Furthermore, the increase of algaecide dose could lead to the cell lysis, as well as release of intracellular MC-LR that enhanced the accumulation of extracellular MC-LR. The order of MC-LR release potential for the four algaecides was CuSO{sub 4} > H{sub 2}O{sub 2} > diuron > EMA. Highlights: • PAM was used to investigate the effects of algaecides on Microcystis aeruginosa. • We estimate the release of potassium (K{sup +}) from cell membrane for cell lysis. • The risk of microcystin-LR release was evaluated after algaecides exposure. • The order of MC-LR release potential was copper sulfate > hydrogen peroxide > diuron > ethyl 2-methylacetoacetate.

  3. Influence of CuSO4 and chelated copper algaecide exposures on biodegradation of microcystin-LR.

    Science.gov (United States)

    Iwinski, Kyla J; Rodgers, John H; Kinley, Ciera M; Hendrikse, Maas; Calomeni, Alyssa J; McQueen, Andrew D; Geer, Tyler D; Liang, Jenny; Friesen, Vanessa; Haakensen, Monique

    2017-05-01

    Copper exposures from algaecide applications in aquatic systems are hypothesized to impede bacterial degradation of microcystin (MC), a cyanobacterial produced hepatotoxin. Despite regulatory implications of this hypothesis, limited data exist on influences of copper-exposures on MC-degrading bacteria and consequent MC-degradation. In this study, influences of copper-algaecide concentrations and formulations on bacterial composition and microcystin-LR (MCLR) degradation were investigated. Microcystis aeruginosa was exposed to four concentrations (0-5.0 mg Cu L -1 ) of three copper-algaecide formulations, and rates and extents of MCLR degradation were measured. In untreated controls and following exposures of 0.1, 0.5, and 1.0 mg Cu L -1 , MCLR concentrations decreased at a rate of ∼41-53 μg MCLR/L d -1 . Following exposure to 5.0 mg Cu L -1 MCLR degradation rates decreased an order of magnitude to ∼3-7 μg MCLR/L d -1 . Bacterial diversity decreased following copper-exposures greater than 0.1 mg Cu L -1 for all formulations. Relative abundance of certain groups of MC-degrading bacteria identified in treatments increased with increasing copper concentration, suggesting they may be less sensitive to copper exposures than other, MCLR and non MC-degrading heterotrophic bacteria present in the assemblage. Results from this study revealed that copper concentration can influence degradation rates of MCLR, however this influence was not significant within copper concentrations currently registered for use (≤1.0 mg Cu L -1 ) of the tested algaecides. Copper formulation did not significantly alter degradation rates or bacterial composition. These data augment our understanding of the influences of copper algaecide-exposures on MCLR degradation, and can be used to inform more accurate risk evaluations and use of copper-algaecides for management of MCLR-producing cyanobacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Competition between Free-Floating Plants Is Strongly Driven by Previously Experienced Phosphorus Concentrations in the Water Column.

    Directory of Open Access Journals (Sweden)

    Edwin T H M Peeters

    Full Text Available Nutrients can determine the outcome of the competition between different floating plant species. The response of floating plants to current phosphorus levels may be affected by previously experienced phosphorus concentrations because some species have the ability to store excess phosphorus for later use. This might have an impact on their competition. Here, we investigate the effect of previous and actual phosphorus concentrations on the growth rate of free-floating plant species (Azolla filiculoides, Lemna minor/gibba and Ricciocarpus natansand the effect of phosphorus history on the competition between L. minor/gibba and A. filiculoides and between L. minor/gibba and R. natans. As expected, plant growth was lower when previously kept at low instead of high phosphorus concentrations. Growth of L. minor/gibba and A. filiculoides with a phosphorus rich history was comparable for low and high actual phosphorus concentrations, however, internal phosphorus concentrations were significantly lower with low actual phosphorus concentration. This indicates that both species perform luxury phosphorus uptake. Furthermore, internal P concentration in Azolla and Lemna increased within two weeks after a period of P deficit without a strong increase in growth. A. filiculoides in a mixture with L. minor/gibba grew faster than its monoculture. Morphological differences may explain why A. filiculoides outcompeted L. minor/gibba and these differences may be induced by phosphorus concentrations in the past. Growth of L. minor/gibba was only reduced by the presence of A. filiculoides with a high phosphorus history. Growth of L. minor/gibba and R. natans in mixtures was positively affected only when they had a high phosphorus history themselves and their competitor a low phosphorus history. These observations clearly indicate that phosphorus history of competing plants is important for understanding the outcome of the competition. Therefore, actual and previously

  5. The effects of water sample treatment, preparation, and storage prior to cyanotoxin analysis for cylindrospermopsin, microcystin and saxitoxin.

    Science.gov (United States)

    Kamp, Lisa; Church, Jennifer L; Carpino, Justin; Faltin-Mara, Erin; Rubio, Fernando

    2016-02-25

    Cyanobacterial harmful algal blooms occur in freshwater lakes, ponds, rivers, and reservoirs, and in brackish waters throughout the world. The wide variety of cyanotoxins and their congeners can lead to frequent exposure of humans through consumption of meat, fish, seafood, blue-green algal products and water, accidental ingestion of contaminated water and cyanobacterial scum during recreational activities, and inhalation of cyanobacterial aerosols. Cyanotoxins can also occur in the drinking water supply. In order to monitor human exposure, sensitive analytical methods such as enzyme linked immunosorbent assay and liquid chromatography-mass spectrometry are often used. Regardless of the analytical method of choice, some problems regularly occur during sample collection, treatment, storage, and preparation which cause toxin loss and therefore underestimation of the true concentration. To evaluate the potential influence of sample treatment, storage and preparation materials on surface and drinking water samples, the effects of different types of materials on toxin recovery were compared. Collection and storage materials included glass and various types of plastics. It was found that microcystin congeners LA and LF adsorbed to polystyrene, polypropylene, high density polyethylene and polycarbonate storage containers, leading to low recoveries (LR to water samples immediately upon sample collection is critical for accurate analysis. In addition, the effect of various drinking water treatment chemicals on toxin recovery and the behavior of those chemicals in the enzyme linked immunosorbent assays were also studied and are summarized. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. The Dynamics of Microcystis Genotypes and Microcystin Production and Associations with Environmental Factors during Blooms in Lake Chaohu, China

    Directory of Open Access Journals (Sweden)

    Li Yu

    2014-12-01

    Full Text Available Lake Chaohu, which is a large, shallow, hypertrophic freshwater lake in southeastern China, has been experiencing lake-wide toxic Microcystis blooms in recent decades. To illuminate the relationships between microcystin (MC production, the genotypic composition of the Microcystis community and environmental factors, water samples and associated environmental data were collected from June to October 2012 within Lake Chaohu. The Microcystis genotypes and MC concentrations were quantified using quantitative real-time PCR (qPCR and HPLC, respectively. The results showed that the abundances of Microcystis genotypes and MC concentrations varied on spatial and temporal scales. Microcystis exists as a mixed population of toxic and non-toxic genotypes, and the proportion of toxic Microcystis genotypes ranged from 9.43% to 87.98%. Both Pearson correlation and stepwise multiple regressions demonstrated that throughout the entire lake, the abundances of total and toxic Microcystis and MC concentrations showed significant positive correlation with the total phosphorus and water temperature, suggesting that increases in temperature together with the phosphorus concentrations may promote more frequent toxic Microcystis blooms and higher concentrations of MC. Whereas, dissolved inorganic carbon (DIC was negatively correlated with the abundances of total and toxic Microcystis and MC concentrations, indicating that rising DIC concentrations may suppress toxic Microcystis abundance and reduce the MC concentrations in the future. Therefore, our results highlight the fact that future eutrophication and global climate change can affect the dynamics of toxic Microcystis blooms and hence change the MC levels in freshwater.

  7. The Dynamics of Microcystis Genotypes and Microcystin Production and Associations with Environmental Factors during Blooms in Lake Chaohu, China

    Science.gov (United States)

    Yu, Li; Kong, Fanxiang; Zhang, Min; Yang, Zhen; Shi, Xiaoli; Du, Mingyong

    2014-01-01

    Lake Chaohu, which is a large, shallow, hypertrophic freshwater lake in southeastern China, has been experiencing lake-wide toxic Microcystis blooms in recent decades. To illuminate the relationships between microcystin (MC) production, the genotypic composition of the Microcystis community and environmental factors, water samples and associated environmental data were collected from June to October 2012 within Lake Chaohu. The Microcystis genotypes and MC concentrations were quantified using quantitative real-time PCR (qPCR) and HPLC, respectively. The results showed that the abundances of Microcystis genotypes and MC concentrations varied on spatial and temporal scales. Microcystis exists as a mixed population of toxic and non-toxic genotypes, and the proportion of toxic Microcystis genotypes ranged from 9.43% to 87.98%. Both Pearson correlation and stepwise multiple regressions demonstrated that throughout the entire lake, the abundances of total and toxic Microcystis and MC concentrations showed significant positive correlation with the total phosphorus and water temperature, suggesting that increases in temperature together with the phosphorus concentrations may promote more frequent toxic Microcystis blooms and higher concentrations of MC. Whereas, dissolved inorganic carbon (DIC) was negatively correlated with the abundances of total and toxic Microcystis and MC concentrations, indicating that rising DIC concentrations may suppress toxic Microcystis abundance and reduce the MC concentrations in the future. Therefore, our results highlight the fact that future eutrophication and global climate change can affect the dynamics of toxic Microcystis blooms and hence change the MC levels in freshwater. PMID:25474494

  8. Combined effects of microcystin and nitrite on the growth, lipid peroxidation, and antioxidant responses of the freshwater rotifer Brachionus calyciflorus.

    Science.gov (United States)

    Liang, Ye; Chen, Xinglan; Lu, Xuxin; Jin, Sichen; Min, Yuanqi; Yang, Jiaxin

    2017-11-01

    Toxicants released during the degradation of cyanobacterial blooms, such as microcystin-LR (MC-LR) and nitrite (NO 2 -N), affect the growth of aquatic organisms. The freshwater rotifer Brachionus calyciflorus was exposed to solutions with different combined concentrations of MC-LR (0, 10, 50, 100, and 200μgL -1 ) and NO 2 -N (0, 2, 4, 6, and 8mgL -1 ) to assess the combined effects of MC-LR and NO 2 -N on life cycle parameters and oxidative stress. Single solutions of MC-LR 200μgL -1 and NO 2 -N 8mgL -1 were toxic to rotifers. MC-LR combined with NO 2 -N decreased population growth rate (r), survival, and reproduction, but increased reactive oxygen species (ROS), malondialdehyde (MDA), and glutathione (GSH) contents (p0.05). Results showed that cyanobacterial metabolites act synergistically and antagonistically to cause toxicity to B. calyciflorus. ROS-mediated toxicity was considered the mechanism by which MC-LR and NO 2 -N induce damage. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Solar photo-Fenton treatment of microcystin-LR in aqueous environment: Transformation products and toxicity in different water matrices.

    Science.gov (United States)

    Karci, Akin; Wurtzler, Elizabeth M; de la Cruz, Armah A; Wendell, David; Dionysiou, Dionysios D

    2018-05-05

    Transformation products and toxicity patterns of microcystin-LR (MC-LR), a common cyanotoxin in freshwaters, during degradation by solar photo-Fenton process were studied in the absence and presence of two major water components, namely fulvic acid and alkalinity. The transformation products m/z 795, 835, 515/1030 and 532 can be formed through attack of OH on the conjugated carbon double bonds of Adda. Transformation products with m/z 1010, 966 and 513 can be generated through the attack of OH on the methoxy group of Adda. The transformation products m/z 783, 508 and 1012 can be originated from the attack of OH on the cyclic structure of MC-LR. Transformation products (m/z 522, 1028, 1012, 1046 and 514) formed after hydroxylation of the aromatic ring with OH were also identified in this study. The toxicity study revealed that fulvic acid and alkalinity strongly influence the toxicity profiles of solar photo-Fenton treated MC-LR. Fulvic acid enhanced the detoxification whereas low level total alkalinity (1.8 mg L -1 CaCO 3 ) inhibited the detoxification of MC-LR by solar photo-Fenton process as assessed by protein phosphatase-1 (PP-1) inhibition assay. This work provides insights on the utility of solar photo-Fenton destruction of MC-LR in water based on transformation products and toxicity data. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Essential roles of Akt/Snail pathway in microcystin-LR-induced tight junction toxicity in Sertoli cell.

    Science.gov (United States)

    Zhou, Yuan; Geng, Xiao; Chen, Yu; Shi, Hao; Yang, Yan; Zhu, Chan; Yu, Guang; Tang, Zongxiang

    2018-02-01

    Microcystin (MC)-LR is a cyclic heptapeptide that acts as a potent reproductive system toxin. However, the underlying pathways of MCLR-induced reproductive system toxicity have not been well elucidated. The blood-testis barrier is mainly constituted by tight junctions (TJs) between adjacent Sertoli cells in the seminiferous epithelium near the basement membrane. The present study was designed to investigate changes in TJs and the underlying pathway in MC-LR-induced TJs toxicity in Sertoli cell. In our study, the transepithelial electrical resistance (TER) value was decreased in a dose dependent manner due to the markers of TJs occludin, claudin and zonula occludens-1 (ZO-1) expression decline. MC-LR is shown to induce cytotoxicity by inhibiting protein phosphatase 2A (PP2A) activity. Our results also showed that the PP2A activity presented a dose-dependent decline. Moreover, MC-LR stimulated protein expression of snail by Akt/GSK-3β activation. The activated Akt/GSK-3β and snail signaling pathway largely accounted for MC-LRinduced TJs toxicity, which could be partially reversed by snail siRNA interference or AKT chemical inhibitor in TM4 cells. These findings indicated that MC-LR inhibit the protein expression of TJs, and the activation of Akt/Snail signaling pathways due to PP2A inhibition is proposed to participate in this process. Copyright © 2018. Published by Elsevier Ltd.

  11. Microcystins Induces Vascular Inflammation in Human Umbilical Vein Endothelial Cells via Activation of NF-κB

    Directory of Open Access Journals (Sweden)

    Jun Shi

    2015-01-01

    Full Text Available Microcystins (MCs produced by toxic cyanobacteria cause serious water pollution and public health hazard to humans and animals. However, direct molecular mechanisms of MC-LR in vascular endothelial cells (ECs have not been understood yet. In this study, we investigated whether MC-LR induces vascular inflammatory process in cultured human umbilical vein endothelial cells (HUVECs. Our data demonstrated that MC-LR decreased HUVECs proliferation and tube formation and enhanced apoptosis. MC-LR also induced intracellular reactive oxygen species formation (ROS in HUVECs. The MC-LR directly stimulated phosphorylation of NF-κB. Furthermore, MC-LR also increased cell adhesion molecules (ICAM-1 and VCAM-1 expression in HUVECs. Taken together, the present data suggested that MC-LR induced vascular inflammatory process, which may be closely related to the oxidative stress, NF-κB activation, and cell adhesion molecules expression in HUVECs. Our findings may highlight that MC-LR causes potential damage to blood vessels.

  12. Production and sedimentation of peptide toxins nodularin-R and microcystin-LR in the northern Baltic Sea

    Energy Technology Data Exchange (ETDEWEB)

    Kankaanpaeae, Harri T. [Finnish Institute of Marine Research (FIMR), Erik Palmenin aukio 1, FI-00560 Helsinki (Finland)], E-mail: kankaanpaa@fimr.fi; Sjoevall, Olli [Department of Biochemistry and Pharmacy, Abo Akademi University, Tykistoekatu 6, FI-20520 Turku (Finland)], E-mail: olli.sjovall@kokemaki.fi; Huttunen, Maija [Finnish Institute of Marine Research (FIMR), Erik Palmenin aukio 1, FI-00560 Helsinki (Finland)], E-mail: maija.huttunen@fimr.fi; Olin, Miikka [Finnish Institute of Marine Research (FIMR), Erik Palmenin aukio 1, FI-00560 Helsinki (Finland)], E-mail: miikka.olin@helsinki.fi; Karlsson, Krister [Department of Biochemistry and Pharmacy, Abo Akademi University, Tykistoekatu 6, FI-20520 Turku (Finland)], E-mail: krister.karlsson@kolster.fi; Hyvaerinen, Kirsi [Finnish Institute of Marine Research (FIMR), Erik Palmenin aukio 1, FI-00560 Helsinki (Finland)], E-mail: kirsi.hyvarinen@fimr.fi; Sneitz, Laura [Finnish Institute of Marine Research (FIMR), Erik Palmenin aukio 1, FI-00560 Helsinki (Finland)], E-mail: laura.sneitz@luukku.com; Haerkoenen, Janne [Finnish Institute of Marine Research (FIMR), Erik Palmenin aukio 1, FI-00560 Helsinki (Finland)], E-mail: janne.harkonen@evtek.fi; Sipiae, Vesa O. [Finnish Institute of Marine Research (FIMR), Erik Palmenin aukio 1, FI-00560 Helsinki (Finland); Meriluoto, Jussi A.O. [Department of Biochemistry and Pharmacy, Abo Akademi University, Tykistoekatu 6, FI-20520 Turku (Finland)], E-mail: jussi.meriluoto@abo.fi

    2009-04-15

    This seven-year survey was primarily targeted to quantification of production of nodularin-R (NOD-R), a cyclic pentapeptide hepatotoxin, in Baltic Sea cyanobacteria waterblooms. Additionally, NOD-R and microcystin-LR (MC-LR; a cyclic heptapeptide toxin) sedimentation rates and NOD-R sediment storage were estimated. NOD-R production (70-2450 {mu}g m{sup -3}; {approx}1 kg km{sup -2} per season) and sedimentation rates (particles; 0.03-5.7 {mu}g m{sup -2} d{sup -1}; {approx}0.3 kg km{sup -2} per season) were highly variable over space and time. Cell numbers of Nodularia spumigena did not correlate with NOD-R quantities. Dissolved NOD-R comprised 57-100% of total NOD-R in the predominantly senescent, low-intensity phytoplankton blooms and seston. Unprecedentedly intensive MC-LR sedimentation (0.56 {mu}g m{sup -2} d{sup -1}) occurred in 2004. Hepatotoxin sedimentation rates highly exceeded those of anthropogenic xenobiotics. NOD-R storage in surficial sediments was 0.4-20 {mu}g kg{sup -1} ({approx}0.1 kg km{sup -2}). Loss of NOD-R within the chain consisting of phytoplankton, seston and soft sediments seemed very effective. - Production of nodularin-R in pelagic Baltic Sea takes place in a scale of up to kilograms per square kilometre.

  13. Mechanism and Reaction Pathways for Microcystin-LR Degradation through UV/H2O2 Treatment.

    Directory of Open Access Journals (Sweden)

    Yafeng Liu

    Full Text Available Microcystin-LR (MCLR is the most common cyanotoxin in contaminated aquatic systems. MCLR inhibits protein phosphatases 1 and 2A, leading to liver damage and tumor formation. MCLR is relatively stable owing to its cyclic structures. The combined UV/H2O2 technology can degrade MCLR efficiently. The second-order rate constant of the reaction between MCLR and hydroxyl radical (·OH is 2.79(±0.23×1010 M-1 s-1 based on the competition kinetics model using nitrobenzene as reference compound. The probable degradation pathway was analyzed through liquid chromatography mass spectrometry. Results suggested that the major destruction pathways of MCLR were initiated by ·OH attack on the benzene ring and diene of the Adda side chain. The corresponding aldehyde or ketone peptide residues were formed through further oxidation. Another minor destruction pathway involved ·OH attack on the methoxy group of the Adda side chain, followed by complete removal of the methoxy group. The combined UV/H2O2 system is a promising technology for MCLR removal in contaminated aquatic systems.

  14. Effects of limonene stress on the growth of and microcystin release by the freshwater cyanobacterium Microcystis aeruginosa FACHB-905.

    Science.gov (United States)

    Hu, Xi; Liu, Yunguo; Zeng, Guangming; Hu, Xinjiang; Wang, Yaqin; Zeng, Xiaoxia

    2014-07-01

    The effects of limonene exposure on the growth of Microcystisaeruginosa and the release of toxic intracellular microcystin (MCY) were tested by evaluating the results obtained from the batch culture experiments with M. aeruginosa FACHB-905. The time series of cell as well as intracellular and extracellular MCY concentrations were evaluated during 5d of the incubation. After exposure to limonene, the number of cells gradually diminished; the net log cell reduction after 5d of the exposure was 3.0, 3.6, and 3.8log when the initial cell densities were set at 1.6×10(7), 1.1×10(6) and 4.1×10(5)cell/mL, respectively. Limonene was found to significantly influence the production and release of MCY. As the limonene exposure could inhibit the increase in the number of cells, the increase in the total MCY concentration in the medium was also inhibited. In the presence of limonene, the intracellular MCY was gradually released into the medium through a gradual reduction in the number of cells. The extracellular MCY concentration in the medium was significantly higher in the limonene-exposed samples than in the control samples, which confirmed that limonene cannot decompose the extracellular MCY. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. A novel method to detect seven microcystins in hard clam and corbicula fluminea by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Yang, Bo; Xu, Jin-Zhong; Ding, Tao; Wu, Bin; Jing, Su; Ding, Shu-jing; Chen, Hui-Lan; Sheng, Chong-Yu; Jiang, Yuan

    2009-11-01

    A simple and reliable method to detect seven microcystins in hard clam and corbicula fluminea, based on liquid chromatography with electrospray ionization and tandem mass spectrometry (LC-ESI-MS/MS), was developed and validated. The sample preparation procedure includes extraction of tissue by methanol, followed by cleanup on a reversed-phase solid phase extraction (SPE) cartridge. With the optimized method, recoveries were between 43.7% and 92.3% for hard clam, 54.3% and 93.8% for corbicula fluminea, the relative standard deviations (RSD) were less than or equal to 16.2% and 15.7% in hard clam and corbicula fluminea at spiking levels of 1 microg/kg, 2 microg/kg and 5 microg/kg for MC-RR, MC-YR, MC-LR, and MC-LY, and 2 microg/kg, 5 microg/kg and 10 microg/kg for MC-LA, MC-LW and MC-LF, respectively, the limits of quantitation (LOQ) of this method were ranged from 0.7 microg/kg to 2.0 microg/kg.

  16. Determination of microcystin-LR in drinking water using UPLC tandem mass spectrometry-matrix effects and measurement.

    Science.gov (United States)

    Li, Wei; Duan, Jinming; Niu, Chaoying; Qiang, Naichen; Mulcahy, Dennis

    2011-10-01

    A simple detection method using ultra-performance liquid chromatography electrospray ionisation tandem mass spectrometry (UPLC-ESI-MS-MS) coupled with the sample dilution method for determining trace microcystin-LR (MC-LR) in drinking water is presented. The limit of detection (LOD) was 0.04 µg/L and the limit of quantitation (LOQ) was 0.1 µg/L. Water matrix effects of ionic strength, dissolved organic carbon (DOC) and pH were examined. The results indicate that signal detection intensity for MC-LR was significantly suppressed as the ionic strength increased from ultrapure water condition, whereas it increased slightly with solution pH and DOC at low concentrations. However, addition of methanol (MeOH) into the sample was able to counter the signal suppression effects. In this study, dilution of the tap water sample by adding 4% MeOH (v/v) was observed to be adequate to compensate for the signal suppression. The recoveries of the samples fortified with MC-LR (0.2, 1, and 10 µg/L) for three different tap water samples ranged from 84.4% to 112.9%.

  17. Effects of microcystin-LR, linear alkylbenzene sulfonate and their mixture on lettuce (Lactuca sativa L.) seeds and seedlings.

    Science.gov (United States)

    Wang, Zhi; Xiao, Bangding; Song, Lirong; Wu, Xingqiang; Zhang, Junqian; Wang, Chunbo

    2011-06-01

    Microcystin-LR (MCLR) and linear alkylbenzene sulfonate (LAS) are present widely in aquatic and terrestrial ecosystems, but their combined ecotoxicological risk is unknown. This study investigated the toxic effects of MCLR, LAS and their mixture on lettuce (Lactuca sativa L.) and evaluated MCLR accumulation level in lettuce with or without LAS. The changes in seed germination and shoot/root growth, responses of the antioxidative defense system, and the accumulation of MCLR in lettuce were tested to evaluate the single and combined toxic effect of MCLR and LAS in well-controlled conditions. The results showed that seedling growth (except for root elongation and leaf weight) was more sensitive to toxicant exposure than seed germination. For seedling leaves, lipid peroxidation was not observed when the antioxidative defense system (including superoxide dismutase, catalase and glutathione) was activated to relieve the adverse effects of oxidative stress via different pathways. Our results also confirmed that the interaction between MCLR and LAS was synergistic. Both toxicants in combination not only significantly inhibited seedling growth, but also increased the activities of superoxide dismutase and catalase, as well as the contents of glutathione. Furthermore, LAS dramatically enhanced the accumulation of MCLR in the plant, thus leading to a reduction in quality and yield and posing greater potential risk to humans via consumption of these edible plants.

  18. Detection of trace microcystin-LR on a 20 MHz QCM sensor coated with in situ self-assembled MIPs.

    Science.gov (United States)

    He, Hao; Zhou, Lianqun; Wang, Yi; Li, Chuanyu; Yao, Jia; Zhang, Wei; Zhang, Qingwen; Li, Mingyu; Li, Haiwen; Dong, Wen-fei

    2015-01-01

    A 20 MHz quartz crystal microbalance (QCM) sensor coated with in situ self-assembled molecularly imprinted polymers (MIPs) was presented for the detection of trace microcystin-LR (MC-LR) in drinking water. The sensor performance obtained using the in situ self-assembled MIPs was compared with traditionally synthesized MIPs on 20 MHz and normal 10 MHz QCM chip. The results show that the response increases by more than 60% when using the in situ self-assembly method compared using the traditionally method while the 20 MHz QCM chip provides four-fold higher response than the 10 MHz one. Therefore, the in situ self-assembled MIPs coated on a high frequency QCM chip was used in the sensor performance test to detect MC-LR in tap water. It showed a limit of detection (LOD) of 0.04 nM which is lower than the safety guideline level (1 nM MC-LR) of drinking water in China. The low sensor response to other analogs indicated the high specificity of the sensor to MC-LR. The sensor showed high stability and low signal variation less than 2.58% after regeneration. The lake water sample analysis shows the sensor is possible for practical use. The combination of the higher frequency QCM with the in situ self-assembled MIPs provides a good candidate for the detection of other small molecules. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Construction and analysis of liver suppression subtractive hybridization library of silver carp (Hypophthalmichthys molitrix) intraperitoneally injected with microcystin-LR.

    Science.gov (United States)

    Qu, Xiancheng; Zhang, Kaiyue; Cui, Zhihui; Zhang, Yong; Jiang, Jiaoyun; Feng, Long; Liu, Qigen

    2011-09-01

    Microcystin-LR (MC-LR) is the most frequently studied cyclic heptapeptide hepatotoxin produced by cyanobacteria. The toxin accumulates rapidly in the liver where it exerts most of its damage, but the molecular mechanisms behind its toxicity remain unclear. Here, suppression subtractive hybridization (SSH) was used to identify alterations in gene transcription of the silver carp (Hypophthalmichthys molitrix) after exposure to MC-LR. After hybridization and cloning, the forward and reverse subtractive cDNA libraries were obtained. At random, 150 positive clones (70 forward and 80 reverse) were selected and sequenced from the subtractive libraries, which gave a total of 88 gene fragment sequences (48 forward and 40 reverse). Sequencing analysis and homology searches showed that these ESTs represented 75 unique genes and 13 duplicates. Of the 75 unique genes, 38 shared high homology with fish genes of known functions, including immune-related genes, transporters and some involved in cell metabolism. Four sequenced genes (Fs59, Fs70, Rs2 and Rs15) were analyzed further using semi-quantitative RT-PCR. The genes from the forward library (Fs59 and Fs70) were found to be transcriptionally upregulated, while the genes from the reverse library (Rs2 and Rs15) were found to be transcriptionally downregulated. These results confirmed the successful construction of the subtractive cDNA library that was enriched for genes that were differentially transcribed in the silver carp liver challenged with MC-LR. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Effects of light, microorganisms, farming chemicals and water content on the degradation of microcystin-LR in agricultural soils.

    Science.gov (United States)

    Cao, Qing; Steinman, Alan D; Yao, Lei; Xie, Liqiang

    2018-07-30

    An experiment was conducted to investigate the effect of farming activities on microcystin-LR (MC-LR) degradation in soils. Three farming activities were assessed: 1) fertilization via addition of different nitrogen sources and organic matter; 2) pesticide application by addition of different commercial pesticides; and 3) irrigation by addition of different amount of water. The contribution of the two major degradation processes of MC-LR in soils, photodegradation and biodegradation, were also evaluated. MC-LR was added into the soil samples to create a concentration of 500 μg kg -1 for each treatment. Results showed that natural degradation of MC-LR in soils was mainly by biodegradation rather than photodegradation. MC-degradation was stimulated by the addition of NaNO 3 and humic acid, whereas degradation was inhibited by addition of NH 4 Cl, glucose, and glycine. Application of high concentrations of glyphosate and chlorothalonil significantly inhibited the degradation of MC-LR in soils and the half-life was almost twice as long as the control. No significant effect was found by addition of CO(NH 2 ) 2 and dimethoate. Both low (10%) and high water content (60%) could lead to inhibition of MC-LR degradation. Results from our study help to inform farm practices that could alleviate contamination by MC-LR in agroecosystems. Copyright © 2018. Published by Elsevier Inc.

  1. Liquid chromatography/negative electrospray ionization ion trap MS(2) mass spectrometry application for the determination of microcystins occurrence in Southern Portugal water reservoirs.

    Science.gov (United States)

    Rodrigues, M A; Reis, M P; Mateus, M C

    2013-11-01

    Microcystins (MCs) are toxins produced by cyanobacteria which are common organisms in the phytoplankton of eutrophic lakes, rivers and freshwater reservoirs. In the present work, a novel method of liquid chromatography-electrospray ion trap tandem mass spectrometry (LC/ESI/Ion trap-MS/MS), operated in the negative ionization mode, was developed for the analysis of these cyanotoxins. The method was applied to determine the amounts of total microcystins-LR, -YR and -RR in two water reservoirs in Southern Portugal, namely Alqueva and Beliche. A total of 30 water samples were analysed along 2011. Solid phase extraction (SPE) was used for sample cleaning-up and analyte enrichment. The extracted toxins were separated on a C18 column with a gradient of acetonitrile/water with 0.1% formic acid. Detection of microcystins was carried out using multiple reaction monitoring (MRM) in the negative polarity mode, as this method gave a higher selectivity. The MC-RR, YR and LR quantification limits were 17.9, 31.7 and 15.8 ng/L, respectively; quite below the limits recommended by WHO guidelines for drinking water (1 μg/L). Total MC highest concentrations were found in the warm months of June, July and September in Alqueva sampling sites, with concentrations of MC LR and RR ranging 17-344 and 25-212 ng/L, respectively, showing comparable results for MC-RR and LR and slightly lower concentration of MC-YR. Detected values for Beliche reservoir were below quantification limits. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Label-free Detection of Microcystin-LR in Waters Using Real-Time Potentiometric Biosensors Based on Single-Walled Carbon Nanotubes Imprinted Polymers

    OpenAIRE

    Queirós, Raquel B.; Noronha, João P. C.; Marques, P.V.S.; Sales, M. Goreti F.

    2012-01-01

    Microcystin-LR (MC-LR) is a dangerous toxin found in environmental waters, quantified by high performance liquid chromatography and/or enzyme-linked immunosorbent assays. Quick, low cost and on-site analysis is thus required to ensure human safety and wide screening programs. This work proposes label-free potentiometric sensors made of solid-contact electrodes coated with a surface imprinted polymer on the surface of Multi-Walled Carbon NanoTubes (CNTs) incorporated in a polyvinyl chloride me...

  3. Selective reduction of C=C double bonds in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of microcystins.

    Science.gov (United States)

    Deleuze, Christelle; De Pauw, Edwin; Quinton, Loic

    2010-01-01

    Cyanobacteria are photosynthetic bacteria encountered in various aquatic environments. Some of them are able to produce powerful toxins called cyanotoxins. Among cyanotoxins, microcystins (MCs) constitute a group of closely related cyclic heptapeptides. Their sequences are made up of classical amino acids as well as post- translational modified ones. Interestingly, in vivo metabolism of microcystins seems to be greatly dependent on various minor structural differences and particularly those of the seventh amino acid, which can be either dehydroalanine (or a derivative), dehydroaminobutyric acid (or a derivative), serine or alanine. As a consequence, microcystins have been classified on the basis of the nature of this singular amino acid. A major difficulty in the classification of such toxins is that some of them share the same molecular masses and the same molecular formulas. Consequently, a simple mass measurement is not sufficient to determine the structure and the class of a toxin of interest. Heavy and expensive techniques are used to classify them, such as multi-dimensional nuclear magnetic resonance and amino acid analysis. In this work, a new matrix-assisted laser desorption/ionization time-of-flight method leading to an easy classification of MCs is proposed. The methodology relies on the reductive properties of the matrix 1,5-diaminonaphtalene (1,5-DAN) which appears to be able to selectively reduce the double carbon-carbon bond belonging to the seventh amino acid. Moreover, the yield of reduction seems to be influenced by the degree of substitution of this double bond, allowing a discrimination between dehydroalanine and dehydroaminobutyric acid. This selective reduction was confirmed by the study of three synthetic peptides by mass spectrometry and tandem mass spectrometry. According to these results, the use of reductive matrices seems to be promising in the study of microcystins and in their classification. More generally, 1,5-DAN allows the selective

  4. THE TOXIC CYANOBACTERIUM NOSTOC SP. STRAIN 152 PRODUCES HIGHEST AMOUNTS OF MICROCYSTIN AND NOSTOPHYCIN UNDER STRESS CONDITIONS.

    Science.gov (United States)

    Kurmayer, Rainer

    2011-02-01

    The understanding of how environmental factors regulate toxic secondary metabolite production in cyanobacteria is important to guarantee water quality. Very little is known on the regulation of toxic secondary metabolite production in benthic cyanobacteria. In this study the physiological regulation of the production of the toxic heptapeptide microcystin (MC) and the non-toxic related peptide nostophycin (NP) in the benthic cyanobacterium Nostoc sp. strain 152 was studied under contrasting environmental conditions. I used a 2(k) levels factorial design, where k is the number of four factors that have been tested: Reduction in temperature (20 vs. 12°C), irradiance (50 vs. 1 μmol · m(-2) · s(-1)), P-PO(4) (144 vs. 0.14 μM P-PO(4)), N-NO(3) (5.88 mM vs. N-NO(3) free). While the growth rate was reduced more than hundred fold under most severe conditions of temperature, irradiance, and phosphate reduction the production of MC and NP never ceased. The MC and NP contents per cell varied at maximum 5- and 10.6-fold each, however the physiological variation did not outweigh the highly significant linear relationship between the daily cell division rate and the MC and NP net production rates. Surprisingly the MC and NP contents per cell showed a maximum under P-PO(4) reduced and irradiance reduced conditions. Both intra- and extracellular MC and NP concentrations were negatively related to P-PO(4) and irradiance. It is concluded that the proximate factor behind maximal cellular MC and NP contents is physiological stress.

  5. Elimination of microcystin-LR and residual Mn species using permanganate and powdered activated carbon: Oxidation products and pathways.

    Science.gov (United States)

    Jeong, Boyoung; Oh, Min-Seok; Park, Hyun-Mee; Park, Chanhyuk; Kim, Eun-Ju; Hong, Seok Won

    2017-05-01

    The oxidation of microcystin-LR (MC-LR) in deionized water (DI) and river water using potassium permanganate (KMnO 4 ) at a neutral pH and at 23 ± 2 °C was investigated. These two aqueous systems (i.e., DI and river water) gave comparable second-order rate constants (289.9 and 285.5 M -1 s -1 (r 2  > 0.99), respectively), which confirmed the effectiveness of this oxidation process for the treatment of natural surface water. The presence of either humic or fulvic acid reduced the removal efficiency of MC-LR, with the latter exhibiting a greater inhibitory effect. Monitoring of MC-LR and residual Mn 2+ levels with adding KMnO 4 (1 mg/L) and powdered activated carbon (PAC, 5-20 mg L -1 ) before and during coagulation, respectively, revealed that 60 min of permanganate pre-oxidation followed by coagulant addition with PAC was the most effective approach for reducing both levels below limits stated by WHO guidelines. The MC-LR degradation products were the result of oxidation occurring at the diene and aromatic moieties of the Adda (3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid) side-chain, in addition to amine bond hydrolysis of the Mdha (N-methyldehydroalanine) moiety. Several toxic by-products with an intact Adda chain were observed during the reaction, but completely disappeared after 60 min. This further supports the conclusion that sufficient contact time with permanganate (i.e., >60 min) is essential to reducing the residual toxicity and maximizing the efficiency of MC-LR oxidation when treating raw water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. A novel photocatalytic material for removing microcystin-LR under visible light irradiation: degradation characteristics and mechanisms.

    Directory of Open Access Journals (Sweden)

    Xin Sui

    Full Text Available Microcystin-LR (MC-LR, a common toxic species in contaminated aquatic systems, persists for long periods because of its cyclic structure. Ag3PO4 is an environment-friendly photocatalyst with relatively good degradation capacity for hazardous organic pollutants. This study aimed to investigate the degradation capacity of Ag3PO4 for MC-LR under visible light.An Ag3PO4 photocatalyst was synthesized by the ion-exchange method and characterized by X-ray diffraction, field-emission scanning electron microscope, and UV-Vis spectrophotometer. MC-LR was quantified in each sample through high-performance liquid chromatograph. The degradation efficiency of MC-LR was affected by initial pH, initial Ag3PO4 concentration, initial MC-LR concentration, and recycle experiments. The degradation intermediates of MC-LR were examined by liquid chromatography-mass spectrometry (LC/MS.The degradation process can be well fitted with the pseudo-first-order kinetic model. The maximum MC-LR degradation rate of 99.98% can be obtained within 5 h under the following optimum conditions: pH of 5.01, Ag3PO4 concentration of 26.67 g/L, and MC-LR concentration of 9.06 mg/L. Nine intermediates were detected and analyzed by LC/MS. Three main degradation pathways were proposed based on the molecular weight of the intermediates and the reaction mechanism: (1 hydroxylation on the aromatic ring of Adda, (2 hydroxylation on the diene bonds of Adda, and (3 internal interactions on the cyclic structure of MC-LR.Ag3PO4 is a highly efficient catalyst for MC-LR degradation in aqueous solutions.

  7. Homogeneous time-resolved fluoroimmunoassay of microcystin-LR using layered WS2 nanosheets as a transducer

    Science.gov (United States)

    Qin, Xiaodan; Wang, Yuanxiu; Song, Bo; Wang, Xin; Ma, Hua; Yuan, Jingli

    2017-06-01

    A homogeneous time-resolved fluoroimmunoassay method for rapid and sensitive detection of microcystin-LR (MC-LR) in water samples was developed based on the interaction between water-soluble WS2 nanosheets and the conjugate of MC-LR with a luminescent Eu3+ complex BHHBCB-Eu3+ (BHHBCB: 1,2-bis[4‧-(1″,1″,1″,2″,2″,3″,3″-heptafluoro-4″,6″-hexanedion-6″-yl)- benzyl]-4-chlorosulfobenzene). The large lateral dimensions and high surface areas of two-dimensional layered WS2 nanosheets enable easy adsorption of the MC-LR-BHHBCB-Eu3+ conjugate, that lead to efficient quenching of the luminescence of Eu3+ complex via energy transfer or electron transfer process. However, the addition of monoclonal anti-MC-LR antibody can induce the formation of MC-LR-BHHBCB-Eu3+/antibody immune complex, which prevents the interaction between WS2 nanosheets and MC-LR-BHHBCB-Eu3+ to result in the restoration of Eu3+ luminescence. This signal transduction mechanism made it possible for analysis of the target MC-LR in a homogeneous system. The present method has advantages of rapidity and simplicity since the B/F (bound reagent/free reagent) separation steps, the solid-phase carrier and antibody labeling or modification process are not necessary. The proposed immunosensing system displayed a wide linear range, good precision and accuracy, and comparable sensitivity with a detection limit of 0.3 μg l-1, which satisfied the World Health Organization (WHO) provisional guideline limit of 1.0 μg l-1 for MC-LR in drinking water.

  8. Quantitatively evaluating detoxification of the hepatotoxic microcystin-LR through the glutathione (GSH) pathway in SD rats.

    Science.gov (United States)

    Guo, Xiaochun; Chen, Liang; Chen, Jun; Xie, Ping; Li, Shangchun; He, Jun; Li, Wei; Fan, Huihui; Yu, Dezhao; Zeng, Cheng

    2015-12-01

    Glutathione (GSH) plays crucial roles in antioxidant defense and detoxification metabolism of microcystin-LR (MC-LR). However, the detoxification process of MC-LR in mammals remains largely unknown. This paper, for the first time, quantitatively analyzes MC-LR and its GSH pathway metabolites (MC-LR-GSH and MC-LR-Cys) in the liver of Sprague-Dawley (SD) rat after MC-LR exposure. Rats received intraperitoneal (i.p.) injection of 0.25 and 0.5 lethal dose 50 (LD50) of MC-LR with or without pretreatment of buthionine-(S,R)-sulfoximine (BSO), an inhibitor of GSH synthesis. The contents of MC-LR-GSH were relatively low during the experiment; however, the ratio of MC-LR-Cys to MC-LR reached as high as 6.65 in 0.5 LD50 group. These results demonstrated that MC-LR-GSH could be converted to MC-LR-Cys efficiently, and this metabolic rule was in agreement with the data of aquatic animals previously reported. MC-LR contents were much higher in BSO + MC-LR-treated groups than in the single MC-LR-treated groups. Moreover, the ratio of MC-LR-Cys to MC-LR decreased significantly after BSO pretreatment, suggesting that the depletion of GSH induced by BSO reduced the detoxification of MCs. Moreover, MC-LR remarkably induced liver damage, and the effects were more pronounced in BSO pretreatment groups. In conclusion, this study verifies the role of GSH in the detoxification of MC-LR and furthers our understanding of the biochemical mechanism for SD rats to counteract toxic cyanobacteria.

  9. Fast screening and quantitation of microcystins in microalgae dietary supplement products and water by liquid chromatography coupled to time of flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ortelli, Didier [Food Authority Control of Geneva, Quai Ernest-Ansermet 22, CP 76, CH-1211 Geneva 4 (Switzerland)], E-mail: didier.ortelli@etat.ge.ch; Edder, Patrick; Cognard, Emmanuelle; Jan, Philippe [Food Authority Control of Geneva, Quai Ernest-Ansermet 22, CP 76, CH-1211 Geneva 4 (Switzerland)

    2008-06-09

    Cyanobacteria, commonly called 'blue-green algae', may accumulate in surface water supplies as 'blooms' and may concentrate on the surface as blue-green 'scums'. Some species of cyanobacteria produce toxins and are of relevance to water supplies and to microalgae dietary supplements. To ensure the safety of drinking water and blue-green algae products, analyses are the only way to determine the presence or absence of toxins. This paper shows the use of ultra performance liquid chromatography (UPLC) coupled to orthogonal acceleration time of flight (TOF) mass spectrometry for the detection and quantitation of microcystins. The method presented is very sensitive, simple, fast, robust and did not require fastidious clean-up step. Limits of detection of 0.1 {mu}g L{sup -1} in water and 0.1-0.2 {mu}g g{sup -1} in microalgae samples were achieved. Method performances were satisfactory and appropriate for monitoring of water and dietary supplements. The method was applied in routine to samples taken from Swiss market or buy on internet website. Among 19 samples, six showed the presence of microcystins LR and LA at harmful levels.

  10. Proteomic and Real-Time PCR analyses of Saccharomyces cerevisiae VL3 exposed to microcystin-LR reveals a set of protein alterations transversal to several eukaryotic models.

    Science.gov (United States)

    Valério, Elisabete; Campos, Alexandre; Osório, Hugo; Vasconcelos, Vitor

    2016-03-15

    Some of the most common toxins present in freshwater, in particular microcystins (MCs), are produced by cyanobacteria. These toxins have a negative impact on human health, being associated with episodes of acute hepatotoxicity and being considered potentially carcinogenic to humans. To date the exact mechanisms of MC-induced toxicity and tumor promotion were not completely elucidated. To get new insights underlying microcystin-LR (MCLR) molecular mechanisms of toxicity we have performed the proteomic profiling using two-dimensional electrophoresis and MALDI-TOF/TOF of Saccharomyces cerevisiae cells exposed for 4 h-1 nM and 1 μM of MCLR, and compared them to the control (cells not exposed to MCLR). We identified 14 differentially expressed proteins. The identified proteins are involved in metabolism, genotoxicity, cytotoxicity and stress response. Furthermore, we evaluated the relative expression of yeast's PP1 and PP2A genes and also of genes from the Base Excision Repair (BER) DNA-repair system, and observed that three out of the five genes analyzed displayed dose-dependent responses. Overall, the different proteins and genes affected are related to oxidative stress and apoptosis, thus reinforcing that it is probably the main mechanism of MCLR toxicity transversal to several organisms, especially at lower doses. Notwithstanding these MCLR responsive proteins could be object of further studies to evaluate their suitability as biomarkers of exposure to the toxin. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Fast screening and quantitation of microcystins in microalgae dietary supplement products and water by liquid chromatography coupled to time of flight mass spectrometry

    International Nuclear Information System (INIS)

    Ortelli, Didier; Edder, Patrick; Cognard, Emmanuelle; Jan, Philippe

    2008-01-01

    Cyanobacteria, commonly called 'blue-green algae', may accumulate in surface water supplies as 'blooms' and may concentrate on the surface as blue-green 'scums'. Some species of cyanobacteria produce toxins and are of relevance to water supplies and to microalgae dietary supplements. To ensure the safety of drinking water and blue-green algae products, analyses are the only way to determine the presence or absence of toxins. This paper shows the use of ultra performance liquid chromatography (UPLC) coupled to orthogonal acceleration time of flight (TOF) mass spectrometry for the detection and quantitation of microcystins. The method presented is very sensitive, simple, fast, robust and did not require fastidious clean-up step. Limits of detection of 0.1 μg L -1 in water and 0.1-0.2 μg g -1 in microalgae samples were achieved. Method performances were satisfactory and appropriate for monitoring of water and dietary supplements. The method was applied in routine to samples taken from Swiss market or buy on internet website. Among 19 samples, six showed the presence of microcystins LR and LA at harmful levels

  12. Mineralization of 14C-labelled plant material by Porcellio scaber (Crustacea, Isopoda)

    International Nuclear Information System (INIS)

    Griffiths, B.S.; Wood, S.; Cheshire, M.V.

    1989-01-01

    Leaf litter was incubated in a mineral soil in the presence or absence of mature Porcellio scaber. The invertebrate caused an increase in the numbers of bacteria, ammonifying bacteria, actinomycetes and protozoa in the soil. The decomposition of 14 C-labelled Lemna gibba was significantly increased by the presence of P. scaber as determined by the total label remaining in the soil and the changes in sugars. 14 C-labelled faeces derived from L. gibba decomposed at a slower rate than the plant tissue from which it originated. (author)

  13. Evaluation of microcystin contamination in blue-green algal dietary supplements using a protein phosphatase inhibition-based test kit

    Directory of Open Access Journals (Sweden)

    David W. Marsan

    2018-03-01

    Full Text Available The cyanobacterium Aphanizomenon flos-aquae (AFA, from Upper-Klamath Lake, Oregon, are used to produce blue-green algal (BGA dietary supplements. The periodic co-occurrence of hepatotoxin-producing contaminant species prompted the Oregon Health Division to establish a limit of 1 μg/g microcystin (MC for products sold in Oregon in 1997. At the federal level, the current good manufacturing practice (CGMP regulations for dietary supplements require manufacturers establish a specification, and test, for limits on contaminants that may adulterate finished products. Despite this, several previous international surveys reported MC in BGA supplements in excess of 1 μg/g. The objectives of this study were (1 identify a reliable, easy to use test kit for the detection of MC in dried BGA materials and (2 use this kit to assess the occurrence of MC contamination in AFA-BGA dietary supplements in the U.S. A commercial protein phosphatase inhibition assay (PPIA, based on the enzyme PP2A, was found to have acceptable relative enzyme inhibition and accuracy for the majority of MC variants tested, including those most commonly identified in commercial samples, making the kit fit for purpose. Using the PPIA kit, 51% (26 of 51 distinct AFA-BGA products had MC ≥0.25 μg/g (the detection limit of the kit, 10 products had MC concentrations between 0.5 and 1.0 μg/g, and 4 products exceeded the limit (1.1–2.8 μg/g. LC-MS/MS confirmed PPIA results ≥0.5 μg/g and determined that MC-LA and MC-LR were the main congeners present. PPIA is a reliable method for the detection of MC contamination in dried BGA dietary supplements produced in the U.S. While the majority of AFA-BGA products contained ≥0.25 μg/g MC, most were at or below 1.0 μg/g, suggesting that manufacturers have adopted this level as a specification in these products; however, variability in recommended serving sizes prevented further analysis of consumer exposure based on the concentrations of MC

  14. Chlorination and ozonation differentially reduced the microcystin content and tumour promoting activity of a complex cyanobacterial extract

    Directory of Open Access Journals (Sweden)

    Iva Sovadinova

    2017-05-01

    Full Text Available Despite intensive research and management efforts in the past decades, cyanobacterial blooms and their toxins, such as microcystins (MCs, continue to represent a major ecological and health problem in fresh waters throughout the world. Our objective was to compare the efficacy of two commonly used drinking water treatment technologies, chlorination and ozonation, in removing MCs and in reducing tumour promotion-related effects of cyanobacteria, such as inhibition of gap junctional intercellular communication (GJIC and activation of mitogen activated protein kinases (MAPKs in a rat liver epithelial stem-like cell line (WB-F344. This combined chemical and bioassay approach demonstrated that ozone effectively removed all MCs from an extract of a globally important bloom-forming cyanobacterium, Microcystis sp. Ozone also significantly reduced the overall tumour promotional potency of the cyanobacterial extract, as indicated by a substantial reduction in the ability of the extract to inhibit GJIC and activate extracellular receptor kinase 1/2 (ERK1/2. Although comparable reduction of total organic carbon was achieved by ozone and chlorine treatment, chlorination was much less effective in removing MCs and reducing the effects on GJIC. Chlorination had a biphasic effect with an observed decrease of extract-induced activation of ERK1/2 at the lower chlorine doses; whereas at high doses of chlorine the by-products of chlorination actually induced the activation of ERK1/2. The extracts induced p38 activation, and chlorination was not effective in reversing this effect, while ozone did reverse this effect, albeit not as much as the activation of ERK1/2. Thus, ozone was effective in reducing the toxicity of cyanobacterial extracts while chlorination was not only lacking efficacy, but at high doses of chlorination further produced by-products that were equally toxic as the untreated samples. Our study indicates the value of using an effect-based approach to

  15. Allelopathic effects of microcystin-LR on the germination, growth and metabolism of five charophyte species and a submerged angiosperm.

    Science.gov (United States)

    Rojo, Carmen; Segura, Matilde; Cortés, Francisco; Rodrigo, María A

    2013-11-15

    Microcystins (MCs) are produced by cyanobacteria in aquatic environments and adversely affect macrophytes at very high concentrations. However, the effects of MC on macrophytes at concentrations of environmental relevance are largely unknown. The main objective of this study was to analyze the allelopathic effects of MC-LR at natural concentrations (1, 8 and 16 μg MC-LR/L) on five charophyte species (Chara aspera, C. baltica, C. hispida, C. vulgaris and Nitella hyalina) and the angiosperm Myriophyllum spicatum. Macrophyte specimens were obtained from a restored area located in Albufera de València Natural Park, a protected coastal Mediterranean wetland. Two different experiments were conducted involving (i) the addition of MC-LR to natural sediment to evaluate its effects on seed germination and (ii) the addition of MC-LR to water cultures of macrophytes to evaluate its effects on growth and metabolic functions. In water, the MC-LR concentration decreased by 84% in two weeks; the loss was not significant in sediment. The first seedlings (all C. hispida) emerged from the wetland sediment following a delay of a few days in the presence of MC-LR. The germination rates in 8 and 16 μg MC-LR/L treatments were 44% and 11% of that occurring in the absence of MC, but these differences disappeared over time. The final density was 6-7 germlings/dm(3). Final germling length was unaffected by MC-LR. Rotifers (Lecane spp.) emerging from the natural sediment during the experiment were favored by MC-LR; the opposite pattern was observed in the cladoceran Daphnia magna. The growth rates of C. vulgaris, C. baltica and N. hyalina were unaffected by MC exposure, whereas those of C. hispida and C. aspera were reduced in the MC treatments relative to the control treatment. The concentration of chlorophyll-a and the in vivo net photosynthetic rate were lower in the presence of MC-LR, even at the lowest concentration, for all of the characeans tested. M. spicatum was sensitive to the

  16. Microcystin-LR nanobody screening from an alpaca phage display nanobody library and its expression and application.

    Science.gov (United States)

    Xu, Chongxin; Yang, Ying; Liu, Liwen; Li, Jianhong; Liu, Xiaoqin; Zhang, Xiao; Liu, Yuan; Zhang, Cunzheng; Liu, Xianjin

    2018-04-30

    Microcystin-LR (MC-LR) is a type of biotoxin that pollutes the ecological environment and food. The study aimed to obtain new nanobodies from phage nanobody library for determination of MC-LR. The toxin was conjugated to keyhole limpet haemocyanin (KLH) and bovine serum albumin (BSA), respectively, then the conjugates were used as coated antigens for enrichment (coated MC-LR-KLH) and screening (coated MC-LR-BSA) of MC-LR phage nanobodies from an alpaca phage display nanobody library. The antigen-specific phage particles were enriched effectively with four rounds of biopanning. At the last round of enrichment, total 20 positive monoclonal phage nanobodies were obtained from the library, which were analyzed after monoclonal phage enzyme linked immunosorbent assay (ELISA), colony PCR and DNA sequencing. The most three positive nanobody genes, ANAb12, ANAb9 and ANAb7 were cloned into pET26b vector, then the nanobodies were expressed in Escherichia coli BL21 respectively. After being purified, the molecular weight (M.W.) of all nanobodies were approximate 15kDa with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The purified nanobodies, ANAb12, ANAb9 and ANAb7 were used to establish the indirect competitive ELISA (IC-ELISA) for MC-LR, and their half-maximum inhibition concentrations (IC 50 ) were 0.87, 1.17 and 1.47μg/L, their detection limits (IC 10 ) were 0.06, 0.08 and 0.12μg/L, respectively. All of them showed strong cross-reactivity (CRs) of 82.7-116.9% for MC-RR, MC-YR and MC-WR, and weak CRs of less than 4.56% for MC-LW, less than 0.1% for MC-LY and MC-LF. It was found that all the IC-ELISAs for MC-LR spiked in tap water samples detection were with good accuracy, stability and repeatability, their recoveries were 84.0-106.5%, coefficient of variations (CVs) were 3.4-10.6%. These results showed that IC-ELISA based on the nanobodies from the alpaca phage display antibody library were promising for high sensitive determination of multiple

  17. Cryptosporidium and microcystins, two problems in making surface water fit for drinking; Criptosporidium y microcistinas, dos problemas en la potabilizacion de las aguas superficiales

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Cedron Rodriguez, A.

    2004-07-01

    Spanish Royal Decree 140/2003 of 7 February 2003 (published in the Spanish Official Gazette, BOE 45 of 21 February 2003 laid down the health criteria for considering water fit for human consumption. this for the first time in Spanish regulations, mention is made of the need to determine the presence of the cryptosporidium genus and other microorganisms or parasites in certain conditions (cloudiness). The decree also provides that in certain other conditions (eutrophication) the level of microcystins must also be determined. Both these polluting agents grow in surface water. This article describes the characteristics of these pollutants, their pathology, recorded epidemic outbreaks, the circumstances in which they can be detected, how the appropriate analyses can be carried out leading to their detection and what treatment are employed to eliminate them during the process of making water fit human consumption. (Author)

  18. Molecular cloning of manganese superoxide dismutase gene in the cladoceran Daphnia magna: Effects of microcystin, nitrite, and cadmium on gene expression profiles

    Energy Technology Data Exchange (ETDEWEB)

    Lyu, Kai; Zhu, Xuexia; Chen, Rui [Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023 (China); Chen, Yafen [State Key Laboratory for Lake Science and Environment, Nanjing Institute of Geography and Limnology, the Chinese Academy of Sciences, Nanjing 210008 (China); Yang, Zhou, E-mail: yangzhou@njnu.edu.cn [Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023 (China)

    2014-03-01

    Graphical abstract: - Highlights: • Daphnia magna MnSOD (Dm-MnSOD) was identified and revealed MnSOD-family features. • The expression of Dm-MnSOD decreased with increased developmental stages. • Dm-MnSOD transcript was kinetically up-regulated by microcystin, nitrite and Cd. • Response of SOD to ubiquitous waterborne pollutants in D. magna was elucidated. • Dm-MnSOD gene is a potential biomarker indicating pollutants in the environment. - Abstract: Superoxide dismutases (SODs) are metalloenzymes that represent one important line of defense against oxidative stress produced by reactive oxygen species in aerobic organisms. Generally, waterborne pollutants caused by irregular anthropogenic activities often result in oxidative damage in aquatic organisms. The aim of this study was to molecularly characterize the manganese superoxide dismutase gene (Dm-MnSOD) in the waterflea, Daphnia magna, and evaluate the mRNA expression patterns quantified by real-time PCR after exposure to three common waterborne pollutants (microcystin-LR, nitrite, and cadmium). The results showed that the full-length Dm-MnSOD sequence consists of 954 bp nucleotides, encoding 215 amino acids, showing well-conserved domains that are required for metal binding and several common characteristics, such as two MnSOD domains. The deduced amino acid sequence of Dm-MnSOD shared over 70% similarity with homologues from Bythograea thermydron, Dromia personata, Cancer pagurus, and Scylla paramamosain. Dm-MnSOD gene expression was up-regulated in response to exposure to the three chemicals tested. The overall results indicated that Dm-MnSOD gene is an inducible gene and potential biomarker indicating these pollutants in the environment.

  19. Biochemical characterization and inhibitory effects of dinophysistoxin-1, okadaic acid and microcystine l-r on protein phosphatase 2a purified from the mussel Mytilus chilensis.

    Directory of Open Access Journals (Sweden)

    MARIELLA RIVAS

    2000-01-01

    Full Text Available Protein phosphatases are involved in many cellular processes. One of the most abundant and best studied members of this class is protein phosphatase type-2A (PP2A. In this study, PP2A was purified from the mussel Mytilus chilensis. Using both SDS-PAGE and size exclusion gel filtration under denaturant conditions, it was confirmed that the PP2A fraction was essentially pure. The isolated enzyme is a heterodimer and the molecular estimated masses of the subunits are 62 and 28 kDa. The isolated PP2A fraction has a notably high p-NPP phosphatase activity, which is inhibited by NaCl. The hydrolytic p-NPP phosphatase activity is independent of the MgCl2 concentration. The time courses of the inhibition of the PP2A activity of p-NPP hydrolysis by increasing concentrations of three phycotoxins that are specific inhibitors of PP2A are shown. Inhibitions caused by Okadaic acid, dinophysistoxin-1 (DTX1, 35-methylokadiac acid and Microcystine L-R are dose-dependent with inhibition constants (Ki of 1.68, 0.40 and 0.27 nM respectively. Microcystine L-R, the most potent phycotoxin inhibitor of PP2A isolated from Mytilus chilensis with an IC50 = 0.25 ng/ml, showed the highest specific inhibition effect an the p-NPP hydrolisis. The calculated IC50 for DTX1 and OA was 0.75 ng/ml and 1.8 ng/ml respectively.

  20. Construction of differentially expressed genes library of bighead carp (Aristichthys nobilis) exposed to microcystin-lr using ssh and expression profile of related genes.

    Science.gov (United States)

    Cui, Zhihui; Zhang, Kaiyue; Qu, Xiancheng; Liu, Qigen

    2011-12-01

    Microcystins (MCs) are hepatotoxic cyclic heptapeptides produced by cyanobacteria (blue-green algae). There are more than 70 MCs variants of which the most common and widely studied is MC-LR. We screened the hepatocellular differentially expressed genes against MC-LR in the bighead carp (Aristichthys nobilis). Suppression subtractive hybridization was used to construct the forward subtracted and reverse subtracted cDNA libraries, and one hundred and thirty two positive clones (seventy one in forward library and sixty one in reverse library) were randomly selected and sequenced. Finally, fifty five reliable sequences from the forward subtracted library were used in a homology search by BLASTn and BLASTx, as were 57 reliable sequences from the reverse subtracted library. Furthermore, eight analyzed sequences from the forward subtracted cDNA library and seven from the reverse subtracted library were found to be non-homologous sequences. The screening identified genes induced by MC-LR in both libraries that are involved in various processes, such as energy metabolism, immunity, and apoptosis. Some are cytoskeleton- and transportation-related genes, while signal transduction-related genes were also found. Significant genes, such as the apoptosis-related gene p53 and the proto-oncogene c-myc, are involved in inhibition of the MC-LR response in the reverse subtracted library. In addition, several immune-related genes, which play an important role in antioxidation and detoxification of MC-LR, were characterized and identified in both of the subtracted libraries. The study provides the basic data to further identify the genes and molecular mechanism of detoxification of microcystins. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Protein phosphatase 2A inhibition and subsequent cytoskeleton reorganization contributes to cell migration caused by microcystin-LR in human laryngeal epithelial cells (Hep-2).

    Science.gov (United States)

    Wang, Beilei; Liu, Jinghui; Huang, Pu; Xu, Kailun; Wang, Hanying; Wang, Xiaofeng; Guo, Zonglou; Xu, Lihong

    2017-03-01

    The major toxic mechanism of Microcystin-LR is inhibition of the activity of protein phosphatase 2A (PP2A), resulting in a series of cytotoxic effects. Our previous studies have demonstrated that microcystin-LR (MCLR) induced very different molecular effects in normal cells and the tumor cell line SMMC7721. To further explore the MCLR toxicity mechanism in tumor cells, human laryngeal epithelial cells (Hep-2) was examined in this study. Western blot, immunofluorescence, immunoprecipitation, and transwell migration assay were used to detect the effects of MCLR on PP2A activity, PP2A substrates, cytoskeleton, and cell migration. The results showed that the protein level of PP2A subunits and the posttranslational modification of the catalytic subunit were altered and that the binding of the AC core enzyme as well as the binding of PP2A/C and α4, was also affected. As PP2A substrates, the phosphorylation of MAPK pathway members, p38, ERK1/2, and the cytoskeleton-associated proteins, Hsp27, VASP, Tau, and Ezrin were increased. Furthermore, MCLR induced reorganization of the cytoskeleton and promoted cell migration. Taken together, direct covalent binding to PP2A/C, alteration of the protein levels and posttranslational modification, as well as the binding of subunits, are the main pattern for the effects of MCLR on PP2A in Hep-2. A dose-dependent change in p-Tau and p-Ezrin due to PP2A inhibition may contribute to the changes in the cytoskeleton and be related to the cell migration in Hep-2. Our data provide a comprehensive exposition of the MCLR mechanism on tumor cells. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 890-903, 2017. © 2016 Wiley Periodicals, Inc.

  2. A 3D graphene-based biosensor as an early microcystin-LR screening tool in sources of drinking water supply

    International Nuclear Information System (INIS)

    Zhang, Wei; Han, Changseok; Jia, Baoping; Saint, Christopher; Nadagouda, Mallikarjuna; Falaras, Polycarpos; Sygellou, Labrini; Vogiazi, Vasileia; Dionysiou, Dionysios D.

    2017-01-01

    Highlights: • 3D graphene-based biosensors can detect MC-LR with remarkable sensitivity. • Good linear correlation between electron-transfer resistance and MC-LR concentration. • A detection limit of 0.04 μg/L MC-LR was accomplished. - Abstract: Recent advances in graphene synthesis and understanding of properties have led to enormous applications in a variety of areas. Graphene and its unique electrical properties can favor electrochemical biosensor applications for aqueous toxin monitoring. Graphene-based biosensors can be used as an alternative to time-consuming, expensive and non-portable conventional methods of analysis involved in water quality monitoring and assessment. In this work, we showcased a three-dimensional (3D) graphene-based biosensor for microcystin-LR (MC-LR) detection and quantification. We report the efficient functionalization and immobilization of microcystin-LR and its antibodies on the facile synthesized CVD 3D graphene. The modified graphene electrodes were characterized by X-ray photoelectron spectroscopy and micro-Raman spectroscopy. Cyclic voltammetry and electrochemical impedance spectroscopy were used to electrochemically characterize the biochemical events on the electrodes. Specifically, as-prepared 3D graphene-based biosensors can detect MC-LR with remarkable sensitivity due to its macro-porous structure and large surface area, and high conductivity. A very good linear correlation of the electron-transfer resistance (R 2 = 0.93) was achieved over 0.05 and 20 μg/L MC-LR concentration range. Also, a detection limit of 0.05 μg/L was accomplished, which is much lower than the World Health Organization (WHO) provisional guideline limit of MC-LR concentration (i.e. 1 μg/L) in drinking water.

  3. PRODUCCIÓN DE LA MACRÓFITA ACUÁTICA Lemna perpusilla UTILIZANDO AGUA RESIDUAL DE UNA INSTALACIÓN PORCINA, CON PROPÓSITOS PARA PRODUCCIÓN DE BIOMASA PARA ACUACULTURA

    Directory of Open Access Journals (Sweden)

    Pablos Reyes DP

    2011-01-01

    Full Text Available Una problemática ambiental impor- tante en instalaciones porcinas es la producción de excretas con alta concentración de nutrientes y su deposición en el ecosistema. Una alternativa para la biorremediación de dicha problemática es utilizar las excretas para la producción de plantas acuáticas que tengan una alta tasa de captación de nutrientes, tal como Lemna perpusilla. En el presente estudio se desarrollaron dos experimentos con el objetivo de estudiar el efecto de la época del año y el tiempo de cosecha sobre la biomasa, composición química y el rendimiento de nutrientes. En el experimento I (enero a abril se utilizó una dosis de fertilización de 20 Lm-2 por cada 20 días y se manejó una densidad de siembra de 200 gm-2, realizando cosechas cada 10 días. Mientras que en el experimento II (mayo a ju- nio se utilizó la misma dosis de fertilización y densidad de siembra, pero cosechando cada seis días. Durante el desarrollo experimental (enero-junio Lemna perpusilla presentó bajo contenido de materia seca (6.87 a 8.87% y fi- bra (11.67 a 12.89%, pero alto contenido de proteína (26.02 a 27.41%. Se determinó que la época y tiempo de cosecha afectan significati- vamente la cosecha total, composición química y rendimiento de nutrientes. Las variables cli- máticas que más influyeron sobre la cosecha total fueron las horas luz y precipitación. Mien- tras que el rendimiento en nutrientes es princi- palmente afectada por la temperatura, hume- dad relativa, horas luz y precipitación.

  4. Ultra-trace levels analysis of microcystins and nodularin in surface water by on-line solid-phase extraction with high-performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Balest, Lydia; Murgolo, Sapia; Sciancalepore, Lucia; Montemurro, Patrizia; Abis, Pier Paolo; Pastore, Carlo; Mascolo, Giuseppe

    2016-06-01

    An on-line solid phase extraction coupled with high-performance liquid chromatography in tandem with mass spectrometry (on-line SPE/HPLC/MS-MS) method for the determination of five microcystins and nodularin in surface waters at submicrogram per liter concentrations has been optimized. Maximum recoveries were achieved by carefully optimizing the extraction sample volume, loading solvent, wash solvent, and pH of the sample. The developed method was also validated according to both UNI EN ISO IEC 17025 and UNICHIM guidelines. Specifically, ten analytical runs were performed at three different concentration levels using a reference mix solution containing the six analytes. The method was applied for monitoring the concentrations of microcystins and nodularin in real surface water during a sampling campaign of 9 months in which the ELISA method was used as standard official method. The results of the two methods were compared showing good agreement when the highest concentration values of MCs were found. Graphical abstract An on-line SPE/HPLC/MS-MS method for the determination of five microcystins and nodularin in surface waters at sub μg L(-1) was optimized and compared with ELISA assay method for real samples.

  5. Assessment of uptake and phytotoxicity of cyanobacterial extracts containing microcystins or cylindrospermopsin on parsley (Petroselinum crispum L.) and coriander (Coriandrum sativum L).

    Science.gov (United States)

    Pereira, Ana L; Azevedo, Joana; Vasconcelos, Vitor

    2017-01-01

    Blooms of harmful cyanobacteria that synthesize cyanotoxins are increasing worldwide. Agronomic plants can uptake these cyanotoxins and given that plants are ultimately ingested by humans, this represents a public health problem. In this research, parsley and coriander grown in soil and watered through 7 days with crude extracts containing microcystins (MCs) or cylindrospermopsin (CYN) in 0.1-1 μg mL -1 concentration range were evaluated concerning their biomass, biochemical parameters and uptake of cyanotoxins. Although biomass, chlorophylls (a and b), carotenoids and glutathione-S-transferase of parsley and coriander exposed to the crude extracts containing MC or CYN had shown variations, these values were not statistically significantly different. Protein synthesis is not inhibited in coriander exposed to MC or CYN and in parsley exposed to MC. Also, glutathione reductase (GR) and glutathione peroxidase (GPx) in parsley and coriander was not affected by exposure to MC, and in coriander, the CYN did not induce statistically significant differences in these two antioxidative enzymes. Only parsley showed statistically significant increase in protein content exposed to 0.5 μg CYN mL -1 (3.981 ± 0.099 mg g -1 FW) compared to control (2.484 ± 0.145 mg g -1 FW), statistically significant decrease in GR exposed to 0.1 μg CYN mL -1 (0.684 ± 0.117 nmol min -1  mg -1 protein) compared to control (1.30 ± 0.06 nmol min -1  mg -1 protein) and statistically significant increase in GPx exposed to 1 μg CYN mL -1 (0.054 ± 0.026 nmol min -1  mg -1 protein) compared to 0.5 μg CYN mL -1 (0.003 ± 0.001 nmol min -1  mg -1 protein). These changes may be due to the induction of defensive mechanisms by plants by the presence of toxic compounds in the soil or probably to a low generation of reactive oxygen species. Furthermore, the parsley and coriander leaves and stems after 10 days of exposure did not accumulate microcystins or

  6. Effects of UV-B radiation on microcystin production of a toxic strain of Microcystis aeruginosa and its competitiveness against a non-toxic strain.

    Science.gov (United States)

    Yang, Zhen; Kong, Fanxiang; Shi, Xiaoli; Yu, Yang; Zhang, Min

    2015-01-01

    Microcystins (MCs) produced by toxic cyanobacteria pose a health hazard to humans and animals. Some environmental factors can alter the MC concentrations by affecting the abundance of toxin-producing strains in a cyanobacteria population and/or their toxin production. In this study, we designed a monoculture and competition experiment to investigate the impacts of UV-B radiation on MC production and the competition between toxin and non-toxin producing strains of Microcystis aeruginosa. UV-B radiation resulted in higher inhibition of the growth and photosynthetic activity of the non-toxin producing strain relative to that observed for the toxin-producing strain. Both intracellular and extracellular MC contents decreased markedly when the toxin-producing strain was exposed to UV-B radiation. In addition, a quantitative real-time PCR assay revealed that the ratio of toxin-producing M. aeruginosa under UV-B exposure was higher than that under PAR alone at an early stage of the experiment. However, its abundance under UV-B exposure was lower compared with the PAR alone treatment after day 12. Our study demonstrated that UV-B radiation has a great impact on the abundance of the toxin-producing strain in the Microcystis population and their toxin production, which suggests that the fluctuation of UV-B radiation affects the MC level of cyanobacteria blooms. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Electrochemical Aptatoxisensor Responses on Nanocomposites Containing Electro-Deposited Silver Nanoparticles on Poly(Propyleneimine Dendrimer for the Detection of Microcystin-LR in Freshwater

    Directory of Open Access Journals (Sweden)

    Mawethu P. Bilibana

    2016-11-01

    Full Text Available A sensitive and reagentless electrochemical aptatoxisensor was developed on cobalt (II salicylaldiimine metallodendrimer (SDD–Co(II doped with electro-synthesized silver nanoparticles (AgNPs for microcystin-LR (L, l-leucine; R, l-arginine, or MC-LR, detection in the nanomolar range. The GCE|SDD–Co(II|AgNPs aptatoxisensor was fabricated with 5’ thiolated aptamer through self-assembly on the modified surface of the glassy carbon electrode (GCE and the electronic response was measured using cyclic voltammetry (CV. Specific binding of MC-LR with the aptamer on GCE|SDD–Co(II|AgNPs aptatoxisensor caused the formation of a complex that resulted in steric hindrance and electrostatic repulsion culminating in variation of the corresponding peak current of the electrochemical probe. The aptatoxisensor showed a linear response for MC-LR between 0.1 and 1.1 µg·L−1 and the calculated limit of detection (LOD was 0.04 µg·L−1. In the detection of MC-LR in water samples, the aptatoxisensor proved to be highly sensitive and stable, performed well in the presence of interfering analog and was comparable to the conventional analytical techniques. The results demonstrate that the constructed MC-LR aptatoxisensor is a suitable device for routine quantification of MC-LR in freshwater and environmental samples.

  8. Analysis of chemokines and reactive oxygen species formation by rat and human neutrophils induced by microcystin-LA, -YR and -LR.

    Science.gov (United States)

    Kujbida, Paula; Hatanaka, Elaine; Campa, Ana; Curi, Rui; Poliselli Farsky, Sandra Helena; Pinto, Ernani

    2008-06-01

    Microcystins (MC), a family of heptapeptide toxins produced by some genera of Cyanobacteria, have potent hepatotoxicity and tumor-promoting activity. Leukocyte infiltration in the liver was observed in MC-induced acute intoxication. Although the mechanisms of hepatotoxicity are still unclear, neutrophil infiltration in the liver may play an important role in triggering toxic injury and tumor development. The present study reports the effects of MC-LA, MC-YR and MC-LR (1 and 1000 nM) on human and rat neutrophils functions in vitro. Cell viability, DNA fragmentation, mitochondrial membrane depolarization and intracellular reactive oxygen species (ROS) levels were measured by flow cytometry. Extracellular ROS content was measured by lucigenin-amplified chemiluminescence, and cytokines were determined by ELISA. We found that these MC increased interleukin-8 (IL-8), cytokine-induced neutrophil chemoattractant-2alphabeta (CINC-2alphabeta) and extracellular ROS levels in human and rat neutrophils. Apart from neutrophil presence during the inflammatory process of MC-induced injury, our results suggest that hepatic neutrophil accumulation is further increased by MC-induced neutrophil-derived chemokine.

  9. Microcystin uptake and biochemical responses in the freshwater clam Corbicula leana P. exposed to toxic and non-toxic Microcystis aeruginosa: Evidence of tolerance to cyanotoxins

    Directory of Open Access Journals (Sweden)

    Thanh-Luu Pham

    2015-01-01

    Full Text Available We investigated the accumulation and adverse effects of toxic and non-toxic Microcystis in the edible clam Corbicula leana. Treated clams were exposed to toxic Microcystis at 100 μg of MC (microcystin-LReq L−1 for 10 days. The experimental organism was then placed in toxin-free water and fed on non-toxic Microcystis for the following 10 days for depuration. Filtering rates (FRs by C. leana of toxic and non-toxic Microcystis and of the green alga Chlorella vulgaris as a control were estimated. Adverse effects were evaluated though the activity of catalase (CAT, superoxide dismutase (SOD and glutathione S-transferase (GST. Clam accumulated MCs (up to 12.7 ± 2.5 μg g−1 dry weight (DW of free MC and 4.2 ± 0.6 μg g−1 DW of covalently bound MC. Our results suggest that although both toxic and non-toxic cyanobacteria caused adverse effects by inducing the detoxification and antioxidant defense system, the clam was quite resistant to cyanotoxins. The estimated MC concentration in C. leana was far beyond the World Health Organization's (WHO provisional tolerable daily intake (0.04 μg kg−1 day−1, suggesting that consuming clams harvested during cyanobacterial blooms carries a high health risk.

  10. Detection of Cyanotoxins, β-N-methylamino-L-alanine and Microcystins, from a Lake Surrounded by Cases of Amyotrophic Lateral Sclerosis

    Directory of Open Access Journals (Sweden)

    Sandra Anne Banack

    2015-01-01

    Full Text Available A cluster of amyotrophic lateral sclerosis (ALS has been previously described to border Lake Mascoma in Enfield, NH, with an incidence of ALS approximating 25 times expected. We hypothesize a possible association with cyanobacterial blooms that can produce β-N-methylamino-L-alanine (BMAA, a neurotoxic amino acid implicated as a possible cause of ALS/PDC in Guam. Muscle, liver, and brain tissue samples from a Lake Mascoma carp, as well as filtered aerosol samples, were analyzed for microcystins (MC, free and protein-bound BMAA, and the BMAA isomers 2,4-diaminobutyric acid (DAB and N-(2-aminoethylglycine (AEG. In carp brain, BMAA and DAB concentrations were 0.043 μg/g ± 0.02 SD and 0.01 μg/g ± 0.002 SD respectively. In carp liver and muscle, the BMAA concentrations were 1.28 μg/g and 1.27 μg/g respectively, and DAB was not detected. BMAA was detected in the air filters, as were the isomers DAB and AEG. These results demonstrate that a putative cause for ALS, BMAA, exists in an environment that has a documented cluster of ALS. Although cause and effect have not been demonstrated, our observations and measurements strengthen the association.

  11. UV-B Exposure Affects the Biosynthesis of Microcystin in Toxic Microcystis aeruginosa Cells and Its Degradation in the Extracellular Space

    Directory of Open Access Journals (Sweden)

    Zhen Yang

    2015-10-01

    Full Text Available Microcystins (MCs are cyclic hepatotoxic heptapeptides produced by cyanobacteria that can be toxic to aquatic and terrestrial organisms. MC synthesis and degradation are thought to be influenced by several different physical and environmental parameters. In this study, the effects of different intensities of UV-B radiation on MC biosynthesis in Microcystis cells and on its extracellular degradation were investigated by mRNA analysis and degradation experiments. Exposure to UV-B at intensities of 1.02 and 1.45 W/m2 not only remarkably inhibited the growth of Microcystis, but also led to a decrease in the MC concentration. In addition, mcyD transcription was decreased under the same UV-B intensities. These results demonstrated that the effects of UV-B exposure on the biosynthesis of MCs in Microcystis cells could be attributed to the regulation of mcy gene transcription. Moreover, the MC concentration was decreased significantly after exposure to different intensities of UV-B radiation. Of the three MC variants (MC-LR, -RR and -YR, L, R and Y are abbreviations of leucine, arginine and tyrosine, MC-LR and MC-YR were sensitive to UV-B radiation, whereas MC-RR was not. In summary, our results showed that UV-B radiation had a negative effect on MC production in Microcystis cells and MC persistence in the extracellular space.

  12. Microcystin-LR acute exposure does not alter in vitro and in vivo ATP, ADP and AMP hydrolysis in adult zebrafish (Danio rerio brain membranes

    Directory of Open Access Journals (Sweden)

    Luiza Wilges Kist

    2012-10-01

    Full Text Available Microcystins (MCs are toxins produced by cyanobacteria during the blooms that could accumulate in aquatic animals and be relocated to higher trophic levels. Adenosine triphosphate (ATP acts as an excitatory neurotransmitter and/or a neuromodulator in the extracellular space playing important roles in physiological and pathological conditions. The aim of this study was, therefore, to evaluate the acute effects of different concentrations of MC-LR on nucleoside triphosphate diphosphohydrolases and 5’-nucleotidade in adult zebrafish (Danio rerio brain membranes. The results have shown no significant changes in ATP, adenosine diphosphate (ADP and adenosine monophosphate (AMP hydrolysis in zebrafish brain membranes. MC-LR in vitro also did not alter ATP, ADP and AMP hydrolysis in the concentrations tested. These findings show that acute exposure to MC-LR did not modulate ectonucleotidase activity in the conditions tested. However, additional studies including chronic exposure should be performed in order to achieve a better understanding about MC-LR toxicity mechanisms in the central nervous system.

  13. A less saline Baltic Sea promotes cyanobacterial growth, hampers intracellular microcystin production, and leads to strain-specific differences in allelopathy.

    Directory of Open Access Journals (Sweden)

    Andreas Brutemark

    Full Text Available Salinity is one of the main factors that explain the distribution of species in the Baltic Sea. Increased precipitation and consequent increase in freshwater inflow is predicted to decrease salinity in some areas of the Baltic Sea. Clearly such changes may have profound effects on the organisms living there. Here we investigate the response of the commonly occurring cyanobacterium Dolichospermum spp. to three salinities, 0, 3 and 6. For the three strains tested we recorded growth, intracellular toxicity (microcystin and allelopathic properties. We show that Dolichospermum can grow in all the three salinities tested with highest growth rates in the lowest salinity. All strains showed allelopathic potential and it differed significantly between strains and salinities, but was highest in the intermediate salinity and lowest in freshwater. Intracellular toxin concentration was highest in salinity 6. In addition, based on monitoring data from the northern Baltic Proper and the Gulf of Finland, we show that salinity has decreased, while Dolichospermum spp. biomass has increased between 1979 and 2013. Thus, based on our experimental findings it is evident that salinity plays a large role in Dolichospermum growth, allelopathic properties and toxicity. In combination with our long-term data analyses, we conclude that decreasing salinity is likely to result in a more favourable environment for Dolichospermum spp. in some areas of the Baltic Sea.

  14. Fast, rugged and sensitive ultra high pressure liquid chromatography tandem mass spectrometry method for analysis of cyanotoxins in raw water and drinking water--First findings of anatoxins, cylindrospermopsins and microcystin variants in Swedish source waters and infiltration ponds.

    Science.gov (United States)

    Pekar, Heidi; Westerberg, Erik; Bruno, Oscar; Lääne, Ants; Persson, Kenneth M; Sundström, L Fredrik; Thim, Anna-Maria

    2016-01-15

    Freshwater blooms of cyanobacteria (blue-green algae) in source waters are generally composed of several different strains with the capability to produce a variety of toxins. The major exposure routes for humans are direct contact with recreational waters and ingestion of drinking water not efficiently treated. The ultra high pressure liquid chromatography tandem mass spectrometry based analytical method presented here allows simultaneous analysis of 22 cyanotoxins from different toxin groups, including anatoxins, cylindrospermopsins, nodularin and microcystins in raw water and drinking water. The use of reference standards enables correct identification of toxins as well as precision of the quantification and due to matrix effects, recovery correction is required. The multi-toxin group method presented here, does not compromise sensitivity, despite the large number of analytes. The limit of quantification was set to 0.1 μg/L for 75% of the cyanotoxins in drinking water and 0.5 μg/L for all cyanotoxins in raw water, which is compliant with the WHO guidance value for microcystin-LR. The matrix effects experienced during analysis were reasonable for most analytes, considering the large volume injected into the mass spectrometer. The time of analysis, including lysing of cell bound toxins, is less than three hours. Furthermore, the method was tested in Swedish source waters and infiltration ponds resulting in evidence of presence of anatoxin, homo-anatoxin, cylindrospermopsin and several variants of microcystins for the first time in Sweden, proving its usefulness. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Efficacy of several treatment in removing cyanobacterial blooms and microcystins; Efectividad de diversos tratamientos de agua en el control de floraciones de cianobacterias de floraciones de cianobacterias y liberacion de sus toxinas (microcistinas)

    Energy Technology Data Exchange (ETDEWEB)

    Moreno Navarro, I. M.; Carmean Fernandez, A. M.

    2003-07-01

    A revision of the different techniques of dri king water treatment employed for the control of cyanobacteria blooms and the release of the toxins that they produce, microcystins, has been performed. Some treatments inhibit the cyanobacteria forth, such as chemical treatment, filtration membranes and domestic filters. However, treatments such as UV irradiation, activated charcola, reverse osmosis, chlorine, permanganate, ozone, photocatalitic oxidation and hydrogen peroxide, are the procedures more often employed in order to destroy MCs. Among these techniques, activated charcoal and ozonization are considered to be the most effective methods to destroy this kind of toxins. (Author) 38 refs.

  16. Water Quality, Cyanobacteria, and Environmental Factors and Their Relations to Microcystin Concentrations for Use in Predictive Models at Ohio Lake Erie and Inland Lake Recreational Sites, 2013-14

    Science.gov (United States)

    Francy, Donna S.; Graham, Jennifer L.; Stelzer, Erin A.; Ecker, Christopher D.; Brady, Amie M. G.; Pam Struffolino,; Loftin, Keith A.

    2015-11-06

    Harmful cyanobacterial “algal” blooms (cyanoHABs) and associated toxins, such as microcystin, are a major water-quality issue for Lake Erie and inland lakes in Ohio. Predicting when and where a bloom may occur is important to protect the public that uses and consumes a water resource; however, predictions are complicated and likely site specific because of the many factors affecting toxin production. Monitoring for a variety of environmental and water-quality factors, for concentrations of cyanobacteria by molecular methods, and for algal pigments such as chlorophyll and phycocyanin by using optical sensors may provide data that can be used to predict the occurrence of cyanoHABs.

  17. Effects of UV-B radiation on microcystin production of a toxic strain of Microcystis aeruginosa and its competitiveness against a non-toxic strain

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhen, E-mail: zhyang@niglas.ac.cn; Kong, Fanxiang, E-mail: fxkong@niglas.ac.cn; Shi, Xiaoli; Yu, Yang; Zhang, Min

    2015-02-11

    Highlights: • UV-B radiation showed higher inhibition to non-toxin producing than toxin-producing strains on growth and photosynthetic activity. • Both intracellular and extracellular MC contents decreased markedly under UV-B radiation. • Higher resistance to UV-B radiation helped toxin-producing M. aeruginosa to predominate in the competition. - Abstract: Microcystins (MCs) produced by toxic cyanobacteria pose a health hazard to humans and animals. Some environmental factors can alter the MC concentrations by affecting the abundance of toxin-producing strains in a cyanobacteria population and/or their toxin production. In this study, we designed a monoculture and competition experiment to investigate the impacts of UV-B radiation on MC production and the competition between toxin and non-toxin producing strains of Microcystis aeruginosa. UV-B radiation resulted in higher inhibition of the growth and photosynthetic activity of the non-toxin producing strain relative to that observed for the toxin-producing strain. Both intracellular and extracellular MC contents decreased markedly when the toxin-producing strain was exposed to UV-B radiation. In addition, a quantitative real-time PCR assay revealed that the ratio of toxin-producing M. aeruginosa under UV-B exposure was higher than that under PAR alone at an early stage of the experiment. However, its abundance under UV-B exposure was lower compared with the PAR alone treatment after day 12. Our study demonstrated that UV-B radiation has a great impact on the abundance of the toxin-producing strain in the Microcystis population and their toxin production, which suggests that the fluctuation of UV-B radiation affects the MC level of cyanobacteria blooms.

  18. Impact of toxic cyanobacteria on gastropods and microcystin accumulation in a eutrophic lake (Grand-Lieu, France) with special reference to Physa (= Physella) acuta

    Energy Technology Data Exchange (ETDEWEB)

    Lance, Emilie, E-mail: emilie.lance@live.fr [ECOBIO, CNRS, Universite de Rennes 1, Avenue du General Leclerc 35042 Rennes (France); Brient, Luc, E-mail: luc.brient@univ-rennes1.fr [ECOBIO, CNRS, Universite de Rennes 1, Avenue du General Leclerc 35042 Rennes (France); Carpentier, Alexandre, E-mail: alexandre.carpentier@univ-rennes1.fr [UMR 7208 BOREA, CRESCO, Museum National d' Histoire Naturelle, 38 rue du Port Blanc, 35800 Dinard (France); Acou, Anthony, E-mail: anthony.acou@mnhn.fr [UMR 7208 BOREA, CRESCO, Museum National d' Histoire Naturelle, 38 rue du Port Blanc, 35800 Dinard (France); Marion, Loic, E-mail: loic.marion@univ-rennes1.fr [ECOBIO, CNRS, Universite de Rennes 1, Avenue du General Leclerc 35042 Rennes (France); Bormans, Myriam, E-mail: myriam.bormans@univ-rennes1.fr [ECOBIO, CNRS, Universite de Rennes 1, Avenue du General Leclerc 35042 Rennes (France); Gerard, Claudia, E-mail: claudia.gerard@univ-rennes1.fr [ECOBIO, CNRS, Universite de Rennes 1, Avenue du General Leclerc 35042 Rennes (France)

    2010-08-01

    Hepatotoxic microcystins (MCs) produced by cyanobacteria are known to accumulate in gastropods following grazing of toxic cyanobacteria and/or absorption of MCs dissolved in water, with adverse effects on life history traits demonstrated in the laboratory. In the field, such effects may vary depending on species, according to their relative sensitivity and ecology. The aims of this study were to i) establish how various intensities of MC-producing cyanobacteria proliferations alter the structure of gastropod community and ii) compare MC tissue concentration in gastropods in the field with those obtained in our previous laboratory experiments on the prosobranch Potamopyrgus antipodarum and the pulmonate Lymnaea stagnalis. We explored these questions through a one-year field study at three stations at Grand-Lieu Lake (France) affected by different intensities of cyanobacteria proliferations. A survey of the community structure and MC content of both cyanobacteria and gastropods was associated with a caging experiment involving P. antipodarum and L. stagnalis. In total, 2592 gastropods belonging to 7 prosobranch and 16 pulmonate species were collected. However, distribution among the stations was unequal with 62% vs 2% of gastropods sampled respectively at the stations with the lowest vs highest concentrations of MC. Irrespective of the station, pulmonates were always more diverse, more abundant and occurred at higher frequencies than prosobranchs. Only the pulmonate Physa acuta occurred at all stations, with abundance and MC tissue concentration ({<=} 4.32 {mu}g g DW{sup -1}) depending on the degrees of MC-producing cyanobacteria proliferations in the stations; therefore, P. acuta is proposed as a potential sentinel species. The caging experiment demonstrated a higher MC accumulation in L. stagnalis ({<=} 0.36 {mu}g g DW{sup -1} for 71% of individuals) than in P. antipodarum ({<=} 0.02 {mu}g g DW{sup -1} for 12%), corroborating previous laboratory observations

  19. Influence of captopril on the cellular uptake and toxic potential of microcystin-LR in non-hepatic adhesive cell lines.

    Science.gov (United States)

    Teneva, Ivanka; Klaczkowska, Dorota; Batsalova, Tsvetelina; Kostova, Zhivka; Dzhambazov, Balik

    2016-03-01

    Microcystin-LR (MC-LR) is a toxin produced by various cyanobacterial strains. Its cytotoxicity is due to inhibition of the protein phosphatases PP1 and PP2A, resulting in hyperphosphorylation of a number of functional and cytoskeletal proteins. To penetrate through the plasma membrane, MC-LR needs specific transporters such the organic anion-transporting polypeptides (OATP) that are highly expressed on the hepatocytes. Hence, our goal was to investigate the role of the membrane transport proteins for the cytotoxic effect of MC-LR on adhesive cell lines different from hepatocytes. We have used three cell lines--A549 (human lung carcinoma), SK-Hep-1 (human liver adenocarcinoma), FL (human amniotic normal cells), and two inhibitors of the OATP (cyclosporine A and captopril). To examine the cytotoxic effect of MC-LR we applied MTT and Neutral Red assays. In addition, a fluorescent staining of the mitochondria by JC-1 was performed. A dose-dependent cytotoxic effect was observed for the three cell lines, as this effect was most pronounced in A549. No cytotoxicity was detected when the captopril was added 2 h before treatment of the cells with MC-LR. Addition of captopril to the cells 2 h after treatment with MC-LR leads to enhancement of the cytotoxic effect. Reduced mitochondrial membrane potential after treatment with MC-LR was detected in the three cell lines, compared to untreated control cells. Results from the NR-cytotoxicity assay indicated that MC-LR does not affect the lysosomes. Captopril is an effective inhibitor of both OATP influx membrane transport proteins and the P-gp efflux pumps involved in the transport of MC-LR. It protects the cells from toxic effects of the cyanotoxin MC-LR. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Exposure of Lycopersicon Esculentum to Microcystin-LR: Effects in the Leaf Proteome and Toxin Translocation from Water to Leaves and Fruits

    Directory of Open Access Journals (Sweden)

    Daniel Gutiérrez-Praena

    2014-06-01

    Full Text Available Natural toxins such as those produced by freshwater cyanobacteria have been regarded as an emergent environmental threat. However, the impact of these water contaminants in agriculture is not yet fully understood. The aim of this work was to investigate microcystin-LR (MC-LR toxicity in Lycopersicon esculentum and the toxin accumulation in this horticultural crop. Adult plants (2 month-old grown in a greenhouse environment were exposed for 2 weeks to either pure MC-LR (100 μg/L or Microcystis aeruginosa crude extracts containing 100 μg/L MC-LR. Chlorophyll fluorescence was measured, leaf proteome investigated with two-dimensional gel electrophoresis and Matrix Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF/TOF, and toxin bioaccumulation assessed by liquid chromatography-mass spectrometry (LC-MS/MS. Variations in several protein markers (ATP synthase subunits, Cytochrome b6-f complex iron-sulfur, oxygen-evolving enhancer proteins highlight the decrease of the capacity of plants to synthesize ATP and to perform photosynthesis, whereas variations in other proteins (ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit and ribose-5-phosphate isomerase suggest an increase of carbon fixation and decrease of carbohydrate metabolism reactions in plants exposed to pure MC-LR and cyanobacterial extracts, respectively. MC-LR was found in roots (1635.21 μg/kg fw, green tomatoes (5.15–5.41 μg/kg fw, mature tomatoes (10.52–10.83 μg/kg fw, and leaves (12,298.18 μg/kg fw. The results raise concerns relative to food safety and point to the necessity of monitoring the bioaccumulation of water toxins in agricultural systems affected by cyanotoxin contamination.

  1. Rapid Characterization of Microcystin-Producing Cyanobacteria in Freshwater Lakes by TSA-FISH (Tyramid Signal Amplification-Fluorescent In Situ Hybridization

    Directory of Open Access Journals (Sweden)

    Luc Brient

    2017-07-01

    Full Text Available Microcystin (MC is a common and widespread toxin which represents a health hazard to humans and animals. MC toxin concentrations are monitored by various direct or proxy techniques (HPLC, LC-MS/MS, ELISA, PPIA, however, these techniques do not discriminate producing species from non-producing ones. In order to simultaneously provide the identity and activity of cyanotoxin producing species in freshwater lakes, we applied simple, and fully detailed, whole cell fluorescent in situ hybridization enhanced by tyramid signal amplification (TSA-FISH. DNA oligonucleotide probes MICR3 and MCYA were targeting 16S rRNA and mcyA-mRNA, respectively. The mcyA gene is coding for the MC synthetase enzyme involved in MC synthesis. Controls were acquired with the general eubacterial 16S rRNA probe EUB338, for TSA-FISH assay, and standard HPLC and LC-MS/MS as standard methods for the measurements of MC concentration. Results obtained from monoclonal strains and natural samples demonstrated a specific identification of Microcystis species and were able to discriminate MC producing from non-producing ones. In addition, the MCYA probe allowed the specific detection of MC-synthetase mRNA within Planktothrix isothrix (Oscillatoriale filaments. Two kinds of mcyA-mRNA labeling were observed in these cells, spots like and plasmid like, which illustrates the well-known plasticity of microbial genome to adapt to environmental stresses. We demonstrated that a simple TSA-FISH assay allows acquiring rapidly dual information of the presence and abundance of potentially toxic species, while identifying species actively producing MC-synthetase mRNA, a proxy of MC toxin. This technique has the potential to be developed into an effective environmental monitoring tool. In addition, detail visualization of cellular mRNAs is powerful for the acquisition of ecological and biomolecular studies of toxic cyanobacteria.

  2. Comparative effects of nodularin and microcystin-LR in zebrafish: 1. Uptake by organic anion transporting polypeptide Oatp1d1 (Slco1d1).

    Science.gov (United States)

    Faltermann, Susanne; Prétôt, René; Pernthaler, Jakob; Fent, Karl

    2016-02-01

    Microcystin-LR (MC-LR) and nodularin are hepatotoxins produced by several cyanobacterial species. Their toxicity is based on active cellular uptake and subsequent inhibition of protein phosphatases PP1/2A, leading to hyperphosphorylation and cell death. To date, uptake of MC-LR and nodularin in fish is poorly understood. Here, we investigated the role of the organic anion transporting polypeptide Oatp1d1 in zebrafish (drOatp1d1, Slco1d1) in cellular uptake in zebrafish. We stably transfected CHO and HEK293 cell lines expressing drOatp1d1. In both transfectants, uptake of MC-LR and nodularin was demonstrated by competitive inhibition of uptake with fluorescent substrate lucifer yellow. Direct uptake of MC-LR was demonstrated by immunostaining, and indirectly by the high cytotoxicity in stable transfectants. By means of a synthesized fluorescent labeled MC-LR derivative, direct uptake was further confirmed in HEK293 cells expressing drOatp1d1. Additionally, uptake and toxicity was investigated in the permanent zebrafish liver cell line ZFL. These cells had only a low relative abundance of drOatp1d1, drOatp2b1 and drOatp1f transcripts, which correlated with the lack of MC-LR induced cytotoxicity and transcriptional changes of genes indicative of endoplasmic reticulum stress, a known effect of this toxin. Our study demonstrates that drOatp1d1 functions as an uptake transporter for both MC-LR and nodularin in zebrafish. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Analysis of the use of microcystin-contaminated water in the growth and nutritional quality of the root-vegetable, Daucus carota.

    Science.gov (United States)

    Machado, J; Azevedo, J; Freitas, M; Pinto, E; Almeida, A; Vasconcelos, V; Campos, A

    2017-01-01

    Toxic cyanobacterial blooms are often observed in freshwaters and may reflect the increased eutrophication of these environments and alterations in climate. Cyanotoxins, such as microcystins (MCs), are an effective threat to many life forms, ranging from plants to humans. Despite the research conducted to date on cyanotoxins, the risks associated to the use of contaminated water in agriculture require further elucidation. To tackle this aim, a research was conducted with the root-vegetable Daucus carota. The specific aims of this work were the following: (i) to evaluate the effects of MC-LR on the plant growth and photosynthesis; (ii) to evaluate the nutritional quality of carrot roots; and (iii) to measure bioaccumulation. To this purpose, young carrots were grown in soil during 1 month in natural conditions and exposed to Mycrocystis aeruginosa aqueous extracts containing environmentally realistic concentrations of MC-LR (10 and 50 MC-LR μg/L). The results showed that MC-LR may decrease root growth after 28 days of exposure to 50 μg/L and increase photosynthetic efficiency. We also observed changes in mineral and vitamin content in carrots as a result of the exposure to contaminated water. Moreover, MC-LR was detected in carrot roots by ELISA at very low concentration 5.23 ± 0.47 ng MC eq./g FW. The soil retained 52.7 % of the toxin potentially available for plants. This result could be attributed to MC-LR adsorption by soil particles or due to microbial degradation of the toxin. We conclude that the prolonged use of MC-LR-contaminated water may affect crop growth, alter the nutritional value of vegetable products, and potentiate contamination.

  4. Effects of Microcystis on development of early life stage Japanese medaka (Oryzias latipes): Comparative toxicity of natural blooms, cultured Microcystis and microcystin-LR.

    Science.gov (United States)

    Saraf, Spencer R; Frenkel, Amy; Harke, Matthew J; Jankowiak, Jennifer G; Gobler, Christopher J; McElroy, Anne E

    2018-01-01

    Freshwater cyanobacterial harmful algal blooms (CyanoHABs) caused by algae in the genus Microcystis have been increasing in frequency and severity in recent decades. Microcystis blooms threaten aquatic organisms through effects associated with the rapid increase of biomass and the production of the hepatotoxin microcystin (MC) by toxic strains. Among fish, effects of blooms are likely to be more severe for early life stages, and physiological impacts on this life stage could significantly impact recruitment and fish populations. This study explores the effects of Microcystis blooms on the development of fish using the model organism, the Japanese medaka (Oryzias latipes), under realistic exposure conditions. Medaka embryos were exposed to natural blooms collected from New York City (USA) lakes, lab cultures of Microcystis, and MC-LR solutions. Field collected samples were more toxic than lab cultures (even when compared at the same algal density or MC concentration), causing decreased survival, premature time to hatch, reduced body length, yolk sac edema, and decreased heart rate, while lab culture exposures only resulted in bradycardia. Heart rate was the most sensitive endpoint measured, being depressed in embryos exposed to both lab cultures and field collected blooms. Generalized linear model analysis indicated bradycardia was statistically associated with both cell densities of blooms and MC concentrations, while single factor analysis indicated that MC concentrations had a stronger correlation compared to cell densities. However, MC exposure could not fully explain the effects observed, as exposures to MC-LR solutions alone were not able to reduce heart rate as severely as algal exposures. Collectively, these experiments indicate that factors beyond exposure to MC or even isolated Microcystis strains influence heart rate of fish exposed to Microcystis blooms. Enhanced mortality, depressed heart rate, and abnormal development observed in response to

  5. Degradation mechanisms of Microcystin-LR during UV-B photolysis and UV/H2O2 processes: Byproducts and pathways.

    Science.gov (United States)

    Moon, Bo-Ram; Kim, Tae-Kyoung; Kim, Moon-Kyung; Choi, Jaewon; Zoh, Kyung-Duk

    2017-10-01

    The removal and degradation pathways of microcystin-LR (MC-LR, [M+H] +  = 995.6) in UV-B photolysis and UV-B/H 2 O 2 processes were examined using liquid chromatography-tandem mass spectrometry. The UV/H 2 O 2 process was more efficient than UV-B photolysis for MC-LR removal. Eight by-products were newly identified in the UV-B photolysis ([M+H] +  = 414.3, 417.3, 709.6, 428.9, 608.6, 847.5, 807.4, and 823.6), and eleven by-products were identified in the UV-B/H 2 O 2 process ([M+H] +  = 707.4, 414.7, 429.3, 445.3, 608.6, 1052.0, 313.4, 823.6, 357.3, 245.2, and 805.7). Most of the MC-LR by-products had lower [M+H] + values than the MC-LR itself during both processes, except for the [M+H] + value of 1052.0 during UV-B photolysis. Based on identified by-products and peak area patterns, we proposed potential degradation pathways during the two processes. Bond cleavage and intramolecular electron rearrangement by electron pair in the nitrogen atom were the major reactions during UV-B photolysis and UV-B/H 2 O 2 processes, and hydroxylation by OH radical and the adduct formation reaction between the produced by-products were identified as additional pathways during the UV-B/H 2 O 2 process. Meanwhile, the degradation by-products identified from MC-LR during UV-B/H 2 O 2 process can be further degraded by increasing H 2 O 2 dose. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Effects of UV-B radiation on microcystin production of a toxic strain of Microcystis aeruginosa and its competitiveness against a non-toxic strain

    International Nuclear Information System (INIS)

    Yang, Zhen; Kong, Fanxiang; Shi, Xiaoli; Yu, Yang; Zhang, Min

    2015-01-01

    Highlights: • UV-B radiation showed higher inhibition to non-toxin producing than toxin-producing strains on growth and photosynthetic activity. • Both intracellular and extracellular MC contents decreased markedly under UV-B radiation. • Higher resistance to UV-B radiation helped toxin-producing M. aeruginosa to predominate in the competition. - Abstract: Microcystins (MCs) produced by toxic cyanobacteria pose a health hazard to humans and animals. Some environmental factors can alter the MC concentrations by affecting the abundance of toxin-producing strains in a cyanobacteria population and/or their toxin production. In this study, we designed a monoculture and competition experiment to investigate the impacts of UV-B radiation on MC production and the competition between toxin and non-toxin producing strains of Microcystis aeruginosa. UV-B radiation resulted in higher inhibition of the growth and photosynthetic activity of the non-toxin producing strain relative to that observed for the toxin-producing strain. Both intracellular and extracellular MC contents decreased markedly when the toxin-producing strain was exposed to UV-B radiation. In addition, a quantitative real-time PCR assay revealed that the ratio of toxin-producing M. aeruginosa under UV-B exposure was higher than that under PAR alone at an early stage of the experiment. However, its abundance under UV-B exposure was lower compared with the PAR alone treatment after day 12. Our study demonstrated that UV-B radiation has a great impact on the abundance of the toxin-producing strain in the Microcystis population and their toxin production, which suggests that the fluctuation of UV-B radiation affects the MC level of cyanobacteria blooms

  7. Photocatalytic degradation and mineralization of microcystin-LR under UV-A, solar and visible light using nanostructured nitrogen doped TiO2

    International Nuclear Information System (INIS)

    Triantis, T.M.; Fotiou, T.; Kaloudis, T.; Kontos, A.G.; Falaras, P.; Dionysiou, D.D.; Pelaez, M.; Hiskia, A.

    2012-01-01

    Highlights: ► N-TiO 2 exhibited effective degradation of MC-LR under UV-A, solar and visible light. ► Complete photocatalytic mineralization of MC-LR was achieved under UV-A and solar light. ► The organic nitrogen is mainly released as ammonium and nitrate ions. - Abstract: In an attempt to face serious environmental hazards, the degradation of microcystin-LR (MC-LR), one of the most common and more toxic water soluble cyanotoxin compounds released by cyanobacteria blooms, was investigated using nitrogen doped TiO 2 (N-TiO 2 ) photocatalyst, under UV-A, solar and visible light. Commercial Degussa P25 TiO 2 , Kronos and reference TiO 2 nanopowders were used for comparison. It was found that under UV-A irradiation, all photocatalysts were effective in toxin elimination. The higher MC-LR degradation (99%) was observed with Degussa P25 TiO 2 followed by N-TiO 2 with 96% toxin destruction after 20 min of illumination. Under solar light illumination, N-TiO 2 nanocatalyst exhibits similar photocatalytic activity with that of commercially available materials such as Degussa P25 and Kronos TiO 2 for the destruction of MC-LR. Upon irradiation with visible light Degussa P25 practically did not show any response, while the N-TiO 2 displayed remarkable photocatalytic efficiency. In addition, it has been shown that photodegradation products did not present any significant protein phosphatase inhibition activity, proving that toxicity is proportional only to the remaining MC-LR in solution. Finally, total organic carbon (TOC) and inorganic ions (NO 2 − , NO 3 − and NH 4 + ) determinations confirmed that complete photocatalytic mineralization of MC-LR was achieved under both UV-A and solar light.

  8. Effectiveness and intermediates of microcystin-LR degradation by UV/H2O2via 265 nm ultraviolet light-emitting diodes.

    Science.gov (United States)

    Liu, Juan; Ye, Jin-Shao; Ou, Hua-Se; Lin, Jialing

    2017-02-01

    Although the degradation of cyanotoxins by 254 nm UV/H 2 O 2 has been well elucidated, the efficiency and mechanism involved are not necessarily true for other UV wavelengths. The degradation of microcystin-LR (MC-LR), a representative cyanotoxin, was explored by UV/H 2 O 2 using 265 nm ultraviolet light-emitting diode (UV-LED). The results indicated that 265 nm UV/H 2 O 2 treatment had a high removal efficiency of MC-LR ([MC-LR] = 0.1 μM, apparent rate constants reached 0.2077 min -1 , half-time at 3.3 min). The qualitative analyses demonstrated that three novel intermediates, C 48 H 74 N 10 O 15 (molecular weight = 1030.5335), C 36 H 58 N 10 O 14 (854.4134), and C 33 H 54 N 10 O 14 (814.3821), were generated in 265 nm UV/H 2 O 2 . Five published intermediates were also confirmed. The generative pathway of these products mainly involved free hydroxyl radical oxidation, resulting in consecutive hydroxyl substitutions and hydroxyl additions of unsaturated bonds in MC-LR. The toxicity of MC-LR was weaken with a relative low mineralization. The electrical energy per order values were calculated to be in the range of 0.00447 to 0.00612 kWh m -3  order -1 for 100-5000 μg L -1 MC-LR. Overall, 265 nm UV-LED/H 2 O 2 can be used as an alternative effective technology to improve the removal efficiency of MC-LR in water.

  9. Occurrence of cyanobacteria and microcystin toxins in raw and treated waters of the Nile River, Egypt: implication for water treatment and human health.

    Science.gov (United States)

    Mohamed, Zakaria A; Deyab, Mohamed Ali; Abou-Dobara, Mohamed I; El-Sayed, Ahmad K; El-Raghi, Wesam M

    2015-08-01

    Monitoring of cyanobacteria and their associated toxins has intensified in raw water sources of drinking water treatment plants (WTPs) in most countries of the world. However, it is not explored yet for Egyptian WTPs. Therefore, this study was undertaken to investigate the occurrence of cyanobacteria and their microcystin (MC) toxins in the Nile River source water of Damietta WTP during warm months (April-September 2013) and to evaluate the removal efficiency of both cyanobacterial cells and MCs by conventional methods used in this plant as a representative of Egyptian drinking WTPs. The results showed that the source water at the intake of Damietta WTP contained dense cyanobacterial population (1.1-6.6 × 107 cells L(-1)) dominated by Microcystis aeruginosa. This bloom was found to produce MC-RR and MC-LR. Both cyanobacterial cell density and intracellular MCs in the intake source water increased with the increase in temperature and nutrients during the study period, with maximum values obtained in August. During treatment processes, cyanobacterial cells were incompletely removed by coagulation/flocculation/sedimentation (C/F/S; 91-96.8%) or sand filtration (93.3-98.9%). Coagulation/flocculation induced the release of MCs into the ambient water, and the toxins were not completely removed or degraded during further treatment stages (filtration and chlorination). MCs in outflow tank water were detected in high concentrations (1.1-3.6 μg L - 1), exceeding WHO provisional guideline value of 1 μg L - 1 for MC-LR in drinking water. Based on this study, regular monitoring of cyanobacteria and their cyanotoxins in the intake source water and at different stages at all WTPs is necessary to provide safe drinking water to consumers or to prevent exposure of consumers to hazardous cyanobacterial metabolites.

  10. Estimation of Ion Competition via Correlated Responsivity Offset in Linear Ion Trap Mass Spectrometry Analysis: Theory and Practical Use in the Analysis of Cyanobacterial Hepatotoxin Microcystin-LR in Extracts of Food Additives

    Science.gov (United States)

    Hrouzek, Pavel; Štys, Dalibor; Martens, Harald

    2013-01-01

    Responsivity is a conversion qualification of a measurement device given by the functional dependence between the input and output quantities. A concentration-response-dependent calibration curve represents the most simple experiment for the measurement of responsivity in mass spectrometry. The cyanobacterial hepatotoxin microcystin-LR content in complex biological matrices of food additives was chosen as a model example of a typical problem. The calibration curves for pure microcystin and its mixtures with extracts of green alga and fish meat were reconstructed from the series of measurement. A novel approach for the quantitative estimation of ion competition in ESI is proposed in this paper. We define the correlated responsivity offset in the intensity values using the approximation of minimal correlation given by the matrix to the target mass values of the analyte. The estimation of the matrix influence enables the approximation of the position of a priori unknown responsivity and was easily evaluated using a simple algorithm. The method itself is directly derived from the basic attributes of the theory of measurements. There is sufficient agreement between the theoretical and experimental values. However, some theoretical issues are discussed to avoid misinterpretations and excessive expectations. PMID:23586036

  11. Alteration in the Expression of Cytochrome P450s (CYP1A1, CYP2E1, and CYP3A11 in the Liver of Mouse Induced by Microcystin-LR

    Directory of Open Access Journals (Sweden)

    Bangjun Zhang

    2015-03-01

    Full Text Available Microcystins (MCs are cyclic heptapeptide toxins and can accumulate in the liver. Cytochrome P450s (CYPs play an important role in the biotransformation of endogenous substances and xenobiotics in animals. It is unclear if the CYPs are affected by MCs exposure. The objective of this study was to evaluate the effects of microcystin-LR (MCLR on cytochrome P450 isozymes (CYP1A1, CYP2E1, and CYP3A11 at mRNA level, protein content, and enzyme activity in the liver of mice the received daily, intraperitoneally, 2, 4, and 8 µg/kg body weight of MCLR for seven days. The result showed that MCLR significantly decreased ethoxyresorufin-O-deethylase (EROD (CYP1A1 and erythromycin N-demthylase (ERND (CYP3A11 activities and increased aniline hydroxylase (ANH activity (CYP2E1 in the liver of mice during the period of exposure. Our findings suggest that MCLR exposure may disrupt the function of CYPs in liver, which may be partly attributed to the toxicity of MCLR in mice.

  12. Sorption of his-tagged Protein G and Protein G onto chitosan/divalent metal ion sorbent used for detection of microcystin-LR.

    Science.gov (United States)

    Demey, Hary; Tria, Scherrine A; Soleri, Romain; Guiseppi-Elie, Anthony; Bazin, Ingrid

    2017-01-01

    A highly sensitive, specific, simple, and rapid chemiluminescence enzyme immunoassay (CLEIA) was developed for the determination of microcystin-LR (MC-LR) by using strategies for oriented immobilization of functionally intact polyclonal antibodies on chitosan surface. Several physicochemical parameters such as metal ion adsorption, hexahistidine-tagged Protein G sorption, the dilution ratio polyclonal antibody concentration, and peroxidase-labeled MC-LR concentration were studied and optimized. The sorption in batch system of G-histidine and G-proteins was studied on a novel sorbent consisting of chitosan/divalent metal ions. Transition metals as Ni ++ and Zn ++ were immobilized through interaction with -NH 2 groups of chitosan in order to supply a material capable to efficiently remove the proteins from aqueous solutions. The maximum uptake of divalent metals onto the chitosan material was found to be 230 mg g -1 for Zn ++ and 62 mg g -1 for Ni ++ . Experimental data were evaluated using the Langmuir and Freundlich models; the results were well fitted with the Langmuir model; chitosan/Ni ++ foam was found to be the best sorbent for G-protein, maximum sorption capacity obtained was 17 mg g -1 , and chitosan/Zn ++ was found to be the best for G-histidine with a maximum sorption capacity of 44 mg g -1 . Kinetic data was evaluated with pseudo-first- and pseudo-second-order models; the sorption kinetics were in all cases better represented by a pseudo-second-order model. Under optimum conditions, the calibration curve obtained for MC-LR gave detection limits of 0.5 ± 0.06 μg L -1 , the 50 % inhibition concentration (IC50) was 2.75 ± 0.03 μg L -1 , and the quantitative detection range was 0.5-25 μg L -1 . The limit of detection (LOD) attained from the calibration curves and the results obtained demonstrate the potential use of CLEIA with chitosan support as a screening tool for the analysis of pollutants in environmental samples.

  13. Photocatalytic degradation and mineralization of microcystin-LR under UV-A, solar and visible light using nanostructured nitrogen doped TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Triantis, T.M.; Fotiou, T. [Laboratory of Catalytic - Photocatalytic Processes (Solar Energy - Environment), Institute of Physical Chemistry, National Center for Scientific Research ' Demokritos' , Neapoleos 25, 15310 Agia Paraskevi, Attiki (Greece); Kaloudis, T. [Organic Micropollutants Laboratory, Athens Water Supply and Sewerage Company (EYDAP SA), WTP Aharnon, Menidi (Greece); Kontos, A.G.; Falaras, P. [Laboratory of Photo-redox Conversion and Storage of Solar Energy, Institute of Physical Chemistry, National Center for Scientific Research ' Demokritos' , Neapoleos 25, 15310 Agia Paraskevi, Attiki (Greece); Dionysiou, D.D.; Pelaez, M. [Environmental Engineering and Science Program, School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, OH 45221-0012 (United States); Hiskia, A., E-mail: hiskia@chem.demokritos.gr [Laboratory of Catalytic - Photocatalytic Processes (Solar Energy - Environment), Institute of Physical Chemistry, National Center for Scientific Research ' Demokritos' , Neapoleos 25, 15310 Agia Paraskevi, Attiki (Greece)

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer N-TiO{sub 2} exhibited effective degradation of MC-LR under UV-A, solar and visible light. Black-Right-Pointing-Pointer Complete photocatalytic mineralization of MC-LR was achieved under UV-A and solar light. Black-Right-Pointing-Pointer The organic nitrogen is mainly released as ammonium and nitrate ions. - Abstract: In an attempt to face serious environmental hazards, the degradation of microcystin-LR (MC-LR), one of the most common and more toxic water soluble cyanotoxin compounds released by cyanobacteria blooms, was investigated using nitrogen doped TiO{sub 2} (N-TiO{sub 2}) photocatalyst, under UV-A, solar and visible light. Commercial Degussa P25 TiO{sub 2}, Kronos and reference TiO{sub 2} nanopowders were used for comparison. It was found that under UV-A irradiation, all photocatalysts were effective in toxin elimination. The higher MC-LR degradation (99%) was observed with Degussa P25 TiO{sub 2} followed by N-TiO{sub 2} with 96% toxin destruction after 20 min of illumination. Under solar light illumination, N-TiO{sub 2} nanocatalyst exhibits similar photocatalytic activity with that of commercially available materials such as Degussa P25 and Kronos TiO{sub 2} for the destruction of MC-LR. Upon irradiation with visible light Degussa P25 practically did not show any response, while the N-TiO{sub 2} displayed remarkable photocatalytic efficiency. In addition, it has been shown that photodegradation products did not present any significant protein phosphatase inhibition activity, proving that toxicity is proportional only to the remaining MC-LR in solution. Finally, total organic carbon (TOC) and inorganic ions (NO{sub 2}{sup -}, NO{sub 3}{sup -} and NH{sub 4}{sup +}) determinations confirmed that complete photocatalytic mineralization of MC-LR was achieved under both UV-A and solar light.

  14. Development and single-laboratory validation of a UHPLC-MS/MS method for quantitation of microcystins and nodularin in natural water, cyanobacteria, shellfish and algal supplement tablet powders.

    Science.gov (United States)

    Turner, Andrew D; Waack, Julia; Lewis, Adam; Edwards, Christine; Lawton, Linda

    2018-02-01

    A simple, rapid UHPLC-MS/MS method has been developed and optimised for the quantitation of microcystins and nodularin in wide variety of sample matrices. Microcystin analogues targeted were MC-LR, MC-RR, MC-LA, MC-LY, MC-LF, LC-LW, MC-YR, MC-WR, [Asp3] MC-LR, [Dha7] MC-LR, MC-HilR and MC-HtyR. Optimisation studies were conducted to develop a simple, quick and efficient extraction protocol without the need for complex pre-analysis concentration procedures, together with a rapid sub 5min chromatographic separation of toxins in shellfish and algal supplement tablet powders, as well as water and cyanobacterial bloom samples. Validation studies were undertaken on each matrix-analyte combination to the full method performance characteristics following international guidelines. The method was found to be specific and linear over the full calibration range. Method sensitivity in terms of limits of detection, quantitation and reporting were found to be significantly improved in comparison to LC-UV methods and applicable to the analysis of each of the four matrices. Overall, acceptable recoveries were determined for each of the matrices studied, with associated precision and within-laboratory reproducibility well within expected guidance limits. Results from the formalised ruggedness analysis of all available cyanotoxins, showed that the method was robust for all parameters investigated. The results presented here show that the optimised LC-MS/MS method for cyanotoxins is fit for the purpose of detection and quantitation of a range of microcystins and nodularin in shellfish, algal supplement tablet powder, water and cyanobacteria. The method provides a valuable early warning tool for the rapid, routine extraction and analysis of natural waters, cyanobacterial blooms, algal powders, food supplements and shellfish tissues, enabling monitoring labs to supplement traditional microscopy techniques and report toxicity results within a short timeframe of sample receipt. The new

  15. Cianobactérias e microcistina em águas de rio destinadas ao abastecimento de centro industrial de Caruaru, PE, Brasil | Cyanobacteria and microcystin in river waters intended to industrial park supply in Caruaru-PE, Brazil

    Directory of Open Access Journals (Sweden)

    Catarina Paula da Silva Ramos

    2016-02-01

    Full Text Available As cianobactérias são responsáveis pela produção de cianotoxinas que, uma vez acumuladas, podem causar sérios danos à saúde humana e animal. As microcistinas são o tipo mais comum de cianotoxinas e são promotoras de tumores hepáticos. O objetivo deste trabalho foi verificar a ocorrência de cianobactérias e determinar a presença da toxina microcistina em amostras de água do rio Ipojuca no perímetro da cidade de Caruaru, PE, Brasil. Amostras de água foram coletadas em cinco pontos estratégicos deste manancial durante treze meses consecutivos. Para a pesquisa de cianobactérias, foi utilizado o método de sedimentação de Utermöhl para quantificação e identificação das espécies. Para a pesquisa de microcistina foi utilizada a Cromatografia Líquida de Alta Eficiência (CLAE. Os resultados mostraram três gêneros produtores de microcistinas e a presença desta toxina em 100% das amostras analisadas, confirmando a relevância do monitoramento de cianobactérias e cianotoxinas em águas de abastecimento público, pois assim como o rio Ipojuca, vários mananciais de Pernambuco apresentam florações de cianobactérias que podem ser tóxicas. Este trabalho mostrou a importância do estudo destes organismos e a detecção de suas toxinas fornecendo subsídios às ações preventivas de vigilância ambiental em saúde. ============================================= Cyanotoxin producing Cyanobacteria can cause serious harm to human and animal health. Microcystins, the most common type of cyanotoxins, promote liver tumors in men. Thus, we aimed at verifying the occurrence of cyanobacteria in water samples from the Ipojuca’s river at the perimeter of Caruaru-PE, Brazil, and determining if the toxin was also present. Water samples were collected at five strategic points over thirteen consecutive months. High Performance Liquid Chromatography (HPLC was used to obtain microcystins. The Utermöhl sedimentation method was used to

  16. Cellular transport of microcystin-LR in rainbow trout (Oncorhynchus mykiss) across the intestinal wall: possible involvement of multidrug resistance-associated proteins.

    Science.gov (United States)

    Bieczynski, Flavia; De Anna, Julieta S; Pirez, Macarena; Brena, Beatríz M; Villanueva, Silvina S M; Luquet, Carlos M

    2014-09-01

    We studied Abcc mediated-transport in middle and posterior intestine of the rainbow trout, Oncorhynchus mykiss. Luminal and serosal transport were evaluated in everted and non-everted intestinal sacs, respectively, incubated with 1-chloro-2,4-dinitrobenzene (CDNB; 200 μM). CDNB enters the cells and is conjugated with glutathione via glutathione S-transferase (GST) to form 2,4-dinitrophenyl-S-glutathione (DNP-SG), a known Abcc substrate. DNP-SG concentration in the bath was recorded every 10 min, in order to calculate the mass-specific transport rate. For evaluating the possible involvement of Abcc proteins in microcystin-LR (MCLR) transport, 1.135 μM MCLR was added to the bath or inside the sacs, in everted or non-everted preparations, respectively. Both luminal and serosal DNP-SG efflux were significantly inhibited by MCLR. A concentration-response curve obtained using strips from middle intestine yielded an IC50 value of 1.33 μM MCLR. The Abcc inhibitor, MK571 produced concentration-dependent inhibition of DNP-SG similar to that produced by MCLR. Since competition of MCLR and CDNB as GST substrates could bias the DNP-SG transport results, we evaluated the effects of MCLR on calcein efflux, which does not depend on GST activity. We applied the non-fluorescent, cell-permeant compound calcein-AM (0.25 μM) to middle intestinal strips and recorded the efflux of its hydrolysis product, the fluorescent Abcc substrate calcein. 2.27 μM MCLR and 3 μM MK571 inhibited calcein efflux (17.39 and 20.2%, respectively). Finally, MCLR interaction with Abcc transporters was evaluated by measuring its toxic intracellular effects. Middle intestinal segments were incubated in saline solution with 1.135 μM MCLR (MC1), 2.27 μM MCLR (MC2), 3 μM MK571 (MK) or 1.135 μM MCLR+3 μM MK571 (MC1/MK). After 1h, GSH concentration, protein phosphatase 1 and 2A (PP1, PP2A) and GST activities were measured in each segment. MC1did not produce significant effect while MC1/MK and MC2

  17. Lettuce (Lactuca sativa L.) leaf-proteome profiles after exposure to cylindrospermopsin and a microcystin-LR/cylindrospermopsin mixture: a concentration-dependent response.

    Science.gov (United States)

    Freitas, Marisa; Campos, Alexandre; Azevedo, Joana; Barreiro, Aldo; Planchon, Sébastien; Renaut, Jenny; Vasconcelos, Vitor

    2015-02-01

    The intensification of agricultural productivity is an important challenge worldwide. However, environmental stressors can provide challenges to this intensification. The progressive occurrence of the cyanotoxins cylindrospermopsin (CYN) and microcystin-LR (MC-LR) as a potential consequence of eutrophication and climate change is of increasing concern in the agricultural sector because it has been reported that these cyanotoxins exert harmful effects in crop plants. A proteomic-based approach has been shown to be a suitable tool for the detection and identification of the primary responses of organisms exposed to cyanotoxins. The aim of this study was to compare the leaf-proteome profiles of lettuce plants exposed to environmentally relevant concentrations of CYN and a MC-LR/CYN mixture. Lettuce plants were exposed to 1, 10, and 100 μg/l CYN and a MC-LR/CYN mixture for five days. The proteins of lettuce leaves were separated by two-dimensional electrophoresis (2-DE), and those that were differentially abundant were then identified by matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF/TOF MS). The biological functions of the proteins that were most represented in both experiments were photosynthesis and carbon metabolism and stress/defense response. Proteins involved in protein synthesis and signal transduction were also highly observed in the MC-LR/CYN experiment. Although distinct protein abundance patterns were observed in both experiments, the effects appear to be concentration-dependent, and the effects of the mixture were clearly stronger than those of CYN alone. The obtained results highlight the putative tolerance of lettuce to CYN at concentrations up to 100 μg/l. Furthermore, the combination of CYN with MC-LR at low concentrations (1 μg/l) stimulated a significant increase in the fresh weight (fr. wt) of lettuce leaves and at the proteomic level resulted in the increase in abundance of a high number of proteins. In

  18. Detection of free and covalently bound microcystins in different tissues (liver, intestines, gills, and muscles) of rainbow trout (Oncorhynchus mykiss) by liquid chromatography–tandem mass spectrometry: Method characterization

    International Nuclear Information System (INIS)

    Cadel-Six, Sabrina; Moyenga, David; Magny, Stéphanie; Trotereau, Sophie; Edery, Marc; Krys, Sophie

    2014-01-01

    So far only a few publications have explored the development of extraction methods of cyanotoxin extracted from complex matrices. With regard to cyanobacterial microcystins (MCs), the data on the contamination of the flesh of aquatic organisms is hard to compare and very limited due to the lack of validated methods. In recent years, evidence that both free and bound fractions of toxin are found in these tissues has highlighted the need to develop effective methods of quantification. Several techniques do exist, but only the Lemieux oxidation has so far been used to investigate complex tissue matrices. In this study, protocols based on the Lemieux approach were adapted for the quantitative chemical analysis of free MC-LR and MMPB derived from bound toxin in the tissues of juvenile trout gavaged with MC-LR. Afterwards, the NF V03 110 guideline was used to characterize the protocols elaborated and evaluate their effectiveness. -- Highlights: • We adapted the quantitative chemical analysis of free and total MC for the tissues of trout. • We characterize with the NF V03 110 guideline the protocols for free MC-LR and MMPB. • We quantify the free MC-LR and MMPB in the tissues of trout gavaged with MC-LR. -- We develop and characterize with the guideline NF V03 110 the protocols for the extraction and quantification of the free and total MC for different matrices

  19. Biomarkers involved in energy metabolism and oxidative stress response in the liver of Goodea gracilis Hubbs and Turner, 1939 exposed to the microcystin-producing Microcystis aeruginosa LB85 strain.

    Science.gov (United States)

    Olivares Rubio, Hugo F; Martínez-Torres, M Lysset; Nájera-Martínez, Minerva; Dzul-Caamal, Ricardo; Domínguez-López, María Lilia; García-Latorre, Ethel; Vega-López, Armando

    2015-09-01

    Goodea gracilis is an endemic fish that only habitats in some water bodies of Central Mexico that are contaminated with cyanobacteria-producing microcystins (MC); however, a lack of information on this topic prevails. With the aim to generate the first approximation about the physiological changes elicited by cyanobacterium that produce MC congeners in this fish species, specimens born in the laboratory was exposed for 96 h to cell densities of 572.5, 1145, 2290, 4580, and 9160 × 10(6) cells of Microcystis aeruginosa strain LB85/L, and a set of novel endpoint related to hepatic gluconeogenesis (ADH/LDH) and pro-oxidant forces O2., H2 O2 ) in addition to biomarkers of oxidative damage and antioxidant response was evaluated in the liver. Results suggest that high inhibition of protein serine/threonine phosphatase (PP) may trigger many metabolic processes, such as those related to hepatic gluconeogenesis (ADH/LDH) and pro-oxidant O2⋅, H2 O2 , TBARS, ROOH, RC=O) as well as antioxidant (SOD, CAT, GPx) response to oxidative stress. Particularly, we observed that inhibition of LDH and PP, and H2 O2 increase and TBARS production were the key damages induced by high densities of M. aeruginosa. However, changes between aerobic and anaerobic metabolism related with ROS metabolism and ADH/LDH balance are apparently an acclimation of this fish species to exposure to cyanobacteria or their MCs. Fish species living in environments potentially contaminated with cyanobacteria or their MCs possess mechanisms of acclimation that allow them to offset the damage induced, even in the case of fish that have never been exposed to MCs. © 2014 Wiley Periodicals, Inc.

  20. A Comparison of growth on mercuric chloride for three Lemnaceae species reveals differences in growth dynamics that effect their suitability for use in either monitoring or remediating ecosystems contaminated with mercury.

    Science.gov (United States)

    Yang, Jingjing; Li, Gaojie; Bishopp, Anthony; Heenatigala, P. P. M.; Hu, Shiqi; Chen, Yan; Wu, Zhigang; Kumar, Sunjeet; Duan, Pengfei; Yao, Lunguang; Hou, Hongwei

    2018-04-01

    Mercury (Hg) is a toxic heavy metal that can alter the ecological balance when it contaminates aquatic ecosystems. Previously, researchers have used various Lemnaceae species either to monitor and/or remove heavy metals from freshwater systems. As Hg contamination is a pressing issue for aquatic systems worldwide, we assessed its impact on the growth of three commonly species of Lemnaceae - Lemna gibba 6745, Lemna minor 6580 and Spirodela polyrhiza 5543. We exposed plants to different concentrations of mercuric chloride (HgCl2) and monitored their growth, including relative growth rate, frond number, and fresh weight. These data were coupled with measurements of starch content, levels of photosynthetic pigment and the activities of antioxidant substances. The growth of all three lines showed significant negative correlations with Hg concentrations, and starch content, photosynthetic pigment, soluble protein and antioxidant enzymes levels were all clearly affected. Our results indicate that the L. gibba line used in this study was the most suitable of the three for biomonitoring of water contaminated with Hg. Accumulation of Hg was highest in the S. polyrhiza line with a bioconcentration factor over 1000, making this line the most suitable of the three tested for use in an Hg bioremediation system.

  1. Colorimetric test for the monitoring of microcystins in cyanobacterial culture and environmental samples from southeast - Brazil Teste colorimétrico usado para o monitoramento de microcistina em cultivo de cianobactérias e em amostras de florações ambientais do sudeste do Brasil

    Directory of Open Access Journals (Sweden)

    Vanessa P.S. Almeida

    2006-06-01

    Full Text Available Microcystins are hepatotoxic heptapeptides produced by some cyanobacterial genera under determined physico-chemical conditions in the environment, which are responsible for the intoxication and death of animals and humans. The detection of microcystins in potable water or recreational water is not carried out routinely in the majority of Brazilian states. The protein phosphatase 1 (PP1 inhibition test is a simple, rapid and reproducible colorimetric method. The applicability of the PP1 inhibition test was tested using Microcystis aeruginosa (strain 1, UFRJ- toxin producer grown under controlled light and temperature condition (12/12h light/dark using 30 muE.m².s-1 at 23ºC in a bioreactor. The total concentrations of P (24, 6 and 4 muM and Fe (4 and 1 muM were varied in ASM-1medium and their effects on the growth rates and toxin production were analyzed. A standard curve of PP1 inhibition by microcystin-LR reached detection limit of 0.01 ng.mL-1. Under the highest concentrations of P (24 muM and Fe (4 muM, the production of microcystin was detected throughout the growth experiment. The highest concentration of microcystin was observed at 6 muM P while at 1 muM Fe, PP1 inhibition was not detected. Samples from environmental blooms in water reservoirs used for human and animal consumption, from southeast Brazil (Belo Horizonte/MG, were tested and quantified for microcystin presence by the PP1 colorimetric test. The concentration of microcystin varied from undetectable to 100 ng.mL-1 in the environmental samples with Microcistis flos-aquae as the predominant cyanobacterial strain.Microcistinas (MC são heptapeptídeos de ação neuro e hepatotóxica produzidas por alguns gêneros de cianobactérias em determinadas condições físico-químicas do ambiente e são responsáveis pela morte e intoxicação de animais e humanos. A detecção de MC em água destinada ao consumo no Brasil ainda não é realizada na maioria dos estados brasileiros. O

  2. Microcystin-LR induces a wide variety of biochemical changes in the A549 human non-small cell lung cancer cell line: Roles for protein phosphatase 2A and its substrates.

    Science.gov (United States)

    Wang, Hanying; Xu, Kailun; Wang, Beilei; Liu, Jinghui; Wang, Xiaofeng; Xing, Mingluan; Huang, Pu; Guo, Zonglou; Xu, Lihong

    2017-03-01

    Our previous studies have described the toxic effects of microcystin-LR (MC-LR) in various normal cell lines and human hepatoma SMMC-7721 cells, but the specific effects of MC-LR in other types of cancer cells with respect to protein phosphatase 2A (PP2A) have not been fully elaborated. A549 human lung adenocarcinoma cells have been identified to express organic anion-transporting polypeptides (OATP) involved in cellular uptake of MC-LR, and thus probably make an appropriate in vitro model to assess MC-LR's cytotoxicity. Hence, in our present study, A549 cells were treated with various concentrations of MC-LR for 24 h. The presence of MC-LR in A549 cells was confirmed, and PP2A activity, PP2A substrates, cytoskeleton, apoptosis, and proliferation were subsequently explored. The results showed that 5-10 μM MC-LR inhibited PP2A activity significantly but 0.5-1 μM MC-LR did not change PP2A activity dramatically. The inhibition could result from the hyperphosphorylation of PP2A/C at Tyr307, an elevation in the total PP2A/C expression and the dissociation of α4/PP2A/C complexes. Moreover, MC-LR led to rearrangements of filamentous actin and microtubules, which might be correlated with the hyperphosphorylation of Ezrin, VASP and HSP27 due to PP2A inhibition and mitogen-activated protein kinase (MAPK) activation. However, exposure to MC-LR for 24 h failed to trigger either apoptosis or proliferation, which might be related to PP2A-inhibition-induced hyperphosphorylation of Bcl-2 and Bad and the activation status of Akt. In conclusion, our data indicated that MC-LR induced extensive molecular and cellular alterations in A549 cells through a PP2A-centered pathway, which differed in some respects from our previous study in SMMC-7721 cells. To our knowledge, this is the first report comprehensively demonstrating the effects of MC-LR in A549 cells, and our findings provide insights into the mechanism of MC-LR toxicity in cancer cells. © 2016 Wiley Periodicals, Inc. Environ

  3. Oxidação de microcistinas-LR em águas pelo íon ferrato(VI Aqueous oxidation of microcystin-LR by ferrate(VI

    Directory of Open Access Journals (Sweden)

    Sérgio João de Luca

    2010-03-01

    Full Text Available Toxinas de cianobactérias têm se tornado um grave problema na produção segura de água para consumo humano e animal. Técnicas convencionais de tratamento falham em atingir padrões de potabilidade. O ferrato(VI de potássio, um composto oxidante e coagulante, mostra potencialidade no tratamento de águas contaminadas. Neste trabalho, são apresentados resultados da oxidação pelo ferrato(VI de uma toxina gerada por cianobactérias, a microcistina-LR. Ensaios de cinética de oxidação e de teste de jarros mostram um valor médio de 0,012 min-1 para a constante de taxa de reação de pseudoprimeira ordem, para concentrações de MC-LR de 100 a 200 µg.L-1 na água bruta. Dosagens de 1,6 a 5,0 mg.L-1 de ferrato(VI sugerem o atendimento ao padrão de potabilidade para microcistinas, mostrando que o oxidante poderá ser empregado como coadjuvante no tratamento de água.Algae toxins are becoming a severe problem in the water treatment industry, especially for human and animal consumption. Traditional treatment processes have failed in complying with water supply standards. Potassium ferrate(VI is a powerful oxidant, disinfectant and, also, a coagulant. In this paper, the results of microcystin-LR oxidation by ferrate(VI ion are presented. Kinetic and jar tests showed a average value of 0,012 min-1 for the pseudo first order reaction rate constant, for 100 and 200 µg.L-1 concentration of MC-LR. Ferrate(VI dosages between 1.6 and 5.0 mg.L-1 suggest that water supply standards for MC-LR can be reached, which means that the oxidant may be employed as coadjuvant in water treatment.

  4. Imunohistochemistry: detection of microcystin in tilápia exposed to Microcystis aeruginosa (Cyanobacteria extract/ Imunoistoquímica: detecção de microcistina em tilápia exposta ao extrato de Microcystis aeruginosa (Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Ken-ichi Harada

    2007-08-01

    Full Text Available The deterioration of the water quality due to aquaculture is associated with eutrophication, with bloom of cyanobacteria. Microcystis aeruginosa is distinguished as main producer of microcystins (MCs, group of hepatotoxins with tumor promoter potential. In the present work immunohistochemical method for detection of MC in tilápia (Oreochromis niloticus, fish submitted to intraperitoneal injection (i.p. or immersion in extract of M. aeruginosa BCCBUSP 262 was developed, using monoclonal antibody anti - MC (M8H5 and polymer peroxidase system. The tilápias (N=42 had been submitted to the seven treatments, three groups inoculated i.p. with 2.0x105, 4.0x105 and 1.0x106 cells. Kg-1 of M. aeruginosa BCCBUSP 262 and four groups exposed to the immersion in different extract concentrations of cyanobacterium. Analyzing liver and muscular tissue for immunohistochemical assay, muscular tissue was not stained. All the animals inoculated i.p. presented positive marking for MC in the liver, but in immersion test, only the ones exposed in the highest dose (1,0x105 cels.mL-1 presented positive marking. Although MC was not detected in muscular tissue, as well as in the liver of animals immersed in extract of M. aeruginosa BCCBUSP 262 in concentrations less than 1.0x105 cels.mL-1, the results would constitute in the base for the methodological development aiming the application of the immunohistochemistry in the rapid diagnosis in quality control of fish.A deterioração da qualidade de água pela piscicultura associa-se à eutrofização, com florescimento de cianobactérias. Microcystis aeruginosa destaca-se como principal produtora de microcistinas (MCs, grupo de hepatotoxinas com potencial promotor de tumor. No presente trabalho desenvolveu-se método imunoistoquímico para a detecção de MC em tilápias (Oreochromis niloticus submetidas à injeção intraperitoneal (i.p. ou imersão em extrato de M. aeruginosa BCCBUSP 262, empregando anticorpo monoclonal

  5. Potential of macrophyte for removing arsenic from aqueous solution Potencial de remoção de arsênio de solução aquosa por macrofita

    Directory of Open Access Journals (Sweden)

    F.P. Guimaraes

    2012-12-01

    Full Text Available The potential of three aquatic macrophytes, Azoll caroliniana, Salvinia minima and Lemna gibba, was evaluated in this work aimed at selection of plants to be used in remediation of environments contaminated by arsenic (As. The experiments were carried out in a greenhouse during six days in pots containing Hoagland solution (¼ ionic strength at As concentrations of 0.5; 2.5 and 5.0 mg L-1. The three species showed greater As accumulation as the concentration of the metalloid in solution increased. However, a reduction was detected in fresh and dry mass gain when the plants were exposed to high As concentrations. The macrophytes showed differences in efficiency of removal of As in solution. A. caroliniana, S. minima and L. gibba accumulated, on average, 0.130; 0.200; and 1.397 mg mDM-1, respectively, when exposed to 5.0 mg L-1 of As. The macrophytes absorbed a greater quantity of As in solution with low phosphate content. The greater As concentration in L. gibba tissues lowered the chlorophyll and carotenoid contents as shown by the high chlorosis incidence. Lemna gibba also exhibited a decrease in leaf size, with the total chlorophyll and carotenoid synthesis not being affected by As in A. caroliniana. This species exhibited purplish leaves with high concentration of anthocyanin, whose presence suggested association to phosphate deficiency. Marginal necrosis occurred on S. minima floating leaves, with the released daughter-plants not showing any visual symptoms during the treatment. The percentage of As removed from the solution decreased when the plants were exposed to high concentrations of the pollutant. Among the three species studied, only L. gibba could be considered an As hyper-accumulator. The use of this plant species for remediation of aquatic environments was shown to be limited and requires further investigation.O potencial de três macrófitas aquáticas - Azolla caroliniana, Salvinia mínima e Lemna gibba - foi avaliado neste

  6. Distribution of microcystin-producing and non-microcystin-producing Microcystis sp. in European freshwater bodies: detection of microcystins and microcystin genes in individual colonies

    Czech Academy of Sciences Publication Activity Database

    Via-Ordorika, L.; Fastner, J.; Kurmayer, R.; Hisbergues, M.; Dittmann, E.; Komárek, Jiří; Erhard, M.; Chorus, I.

    2004-01-01

    Roč. 27, - (2004), s. 592-602 ISSN 0723-2020 R&D Projects: GA AV ČR KSK6005114 Grant - others:Austrian Science Funds(AT) P15709 Institutional research plan: CEZ:AV0Z6005908 Keywords : cyanobacteria * lake management * eutrophication Subject RIV: EF - Botanics Impact factor: 1.933, year: 2004

  7. comparative study on the efficiency of Lemna minor L.

    African Journals Online (AJOL)

    from kaduna refinery and Petro-chemical Company. Water samples were collected from Kaduna ... use in the phytoremediation of water from Kaduna. Refining and Petro-chemical Company since it shows the ..... Wolverton, B.C. and McDonald, R.C. (1979): The Water. Hyacinth: From Prolific Pest to Potential Provider.,Ambio ...

  8. Effectiveness of Vegetated Drainage Ditches for Domestic Sewage Effluent Mitigation.

    Science.gov (United States)

    Kumwimba, Mathieu Nsenga; Zhu, Bo

    2017-05-01

    Plant species have an important role in eco-ditches; however, the Michaelis-Menten kinetic parameters of nutrient uptake, growth rate and purification efficiency of ditch plants and their influences on domestic sewage treatment efficiency are still unclear. Growth rates of all nine species, but especially Lemna gibba, Cladophora and Myriophyllum verticillatum were best in undiluted domestic sewage as opposed to a mixture of domestic sewage. Performance of species to accumulate nutrients was not only species-specific, but was also affected by both sewage treatments. Removal efficiency of nutrients was dependent on both plant species and treatment. Uptake kinetic parameters were significantly affected by both nutrient form and plant species. The maximum uptake rate (Vmax) of NH 4 -N was higher than NO 3 -N. Similarly, Km values for NH 4 -N were greater than NO 3 -N. These results could be used to identify plants for sewage treatment efficiency and enhance water quality in eco-ditch treatment systems.

  9. Potential of macrophytes for removing atrazine from aqueous solution Potencial de macrófitas para remoção de atrazine de solução aquosa

    Directory of Open Access Journals (Sweden)

    F.P Guimarães

    2011-01-01

    Full Text Available The potential of three macrophytes, Azolla caroliniana, Salvinia minima, and Lemna gibba was assessed in this study to select plants for use in environmental remediation contaminated with atrazine. Experiments were carried out in a greenhouse over six days in pots containing Hoagland 0.25 strength nutritive solution at the following atrazine concentrations: 0; 0.01; 0.1; 1.0; 10.0 mg L-1. Decrease in biomass accumulation was observed in the three macrophytes, as well as toxic effects evidenced by the symptomatology developed by the plants which caused their deaths. The chlorosis and necrosis allowed to observe in the plants the high sensitivity of the three species to the herbicide. Plants presented low potential for removal of atrazine in solution when exposed to low concentrations of the herbicide. However, at the 10.0 mg L-1 atrazine concentration, L. gibba and A. caroliniana showed potential to remove the herbicide from the solution (0.016 and 0.018 mg atrazine per fresh mass gram, respectively. This fact likely resulted from the processes of atrazine adsorption by the dead material. The percentage of atrazine removed from the solution by the plants decreased when the plants were exposed to high concentrations of the pollutant. Azolla caroliniana, S. minima, and L. gibba were not effective in removing the herbicide from solution. The use of these species to remedy aquatic environments was shown to be limited.Avaliou-se, neste estudo, o potencial de três macrófitas - Azolla caroliniana, Salvinia minima e Lemna gibba - com vistas à seleção de plantas para remediação de ambientes contaminados por atrazine. Foram realizados experimentos em casa de vegetação durante seis dias, em vasos contendo solução nutritiva Hoagland (0,25 de força iônica, nas seguintes concentrações de atrazine: 0; 0,01; 0,1; 1,0; e 10,0 mg L-1. A redução da biomassa acumulada pelas macrófitas foi observada, bem como os efeitos de toxidez evidenciados pela

  10. Adsorção em carvão ativado em pó para remoção de microcistina de água de abastecimento público Powdered activated carbon adsorption for microcystin removal from public water supply

    Directory of Open Access Journals (Sweden)

    Carla Cristine Müller

    2009-03-01

    Full Text Available A ocorrência de florações de cianobactérias em mananciais de abastecimento público prejudica a qualidade da água, podendo, inclusive, ocasionar a presença de cianotoxinas. A dificuldade de remover as cianotoxinas da água motivou o presente trabalho, cujo objetivo foi o de avaliar a remoção da cianotoxina microcistina empregando diferentes carvões ativados em pó (CAPs. Os CAPs foram caracterizados quanto ao número de iodo, granulometria, distribuição e volume de poros, além das isotermas de Freundlich. Os resultados mostraram que os CAPs de madeira apresentaram os maiores valores do número de iodo, capacidade máxima adsortiva (qe, máx e volume de microporos secundários e mesoporos. A adequada caracterização do CAP é uma etapa importante na sua aquisição pelas estações de tratamento de água, pois índices isolados podem não avaliar corretamente o CAP.The cyanobacterial bloom's occurrence in sources of public supplying harms water quality, even causing cianotoxins presence. The difficulty of the cianotoxins removal from the water has motivated the present work, which objective was to evaluate the removal of the cianotoxin microcystin through the use of different powdered activated carbons (PACs. The PACs were characterized according to its iodine number, granulometry, distribution and volume of pores, besides the Freundlich isotherms. The results showed that the wood PACs presented the highest values of iodine number, maximum adsorptive capacity (qe, max and volume of secondary micropores and mesoporos. The adequate characterization of the PACs is an important stage in its acquisition by the water treatment plants, because isolated indices can not evaluate the PACs correctly.

  11. SIZINTI SUYUNUN ARITIMI İÇİN SU MERCİMEKLERİ KARIŞIMININ KULLANILMASI: I. NUTRİENTLER

    Directory of Open Access Journals (Sweden)

    Murat Topal

    2012-08-01

    Full Text Available Bu çalışmada, sızıntı suyu arıtımı için Lemna gibba L., Lemna minor L., Spirodela polyrrhiza ve Wolffia arrhiza’dan oluşan su mercimekleri karışımı kullanılmış ve bitkili kesikli sistemde nutrientlerin değişimleri araştırılmıştır. Çalışmada, NH4+-N, NO2--N, NO3—N ve O-PO43- konsantrasyonları tespit edilmiştir. Deneysel çalışmalar 2 farklı derinlikte (5 ve 10 cm ve farklı hidrolik bekletme sürelerinde gerçekleştirilmiştir. En yüksek NH4+-N giderim verimi (%75,3, 5 cm derinlikteki reaktörde 9. günde tespit edilmiştir. NO2- -N ve NO3- -N konsantrasyonlarında herhangi bir giderim olmadığı gözlenmiştir. En yüksek O-PO43- giderim verimi 5 cm derinlikteki reaktörde %44,6 olarak tespit edilmiştir.

  12. SIZINTI SUYUNUN ARITIMI İÇİN SU MERCİMEKLERİ KARIŞIMININ KULLANILMASI: II. DİĞER PARAMETRELER

    Directory of Open Access Journals (Sweden)

    Murat Topal

    2012-08-01

    Full Text Available Bu çalışmada, sızıntı suyu arıtımı için Lemna gibba L., Lemna minor L., Spirodela polyrrhiza ve Wolffia arrhiza’dan oluşan su mercimekleri karışımı kullanılmış ve bitkili kesikli sistemde KOİ, pH ve elektriksel iletkenlik değişimleri araştırılmıştır. Deneysel çalışmalar, 4 adet reaktörde oda sıcaklığında gerçekleştirilmiştir. En yüksek KOİ giderim verimi, 5 ve 10 cm derinlikteki reaktörlerde sırasıyla %62,2 ve %60,1 olarak tespit edilmiştir. Başlangıçta 7,91 değerinde olan pH, farklı hidrolik bekletme sürelerinde 7,91-8,49 arasında olmuştur. Başlangıçta 5,59 mS/cm değerinde olan elektriksel iletkenlik, en yüksek 9,46 mS/cm değerine ulaşmıştır.

  13. Effects of dissolved microcystins on growth of planktonic photoautotrophs

    Czech Academy of Sciences Publication Activity Database

    Babica, Pavel; Hilscherová, Klára; Bártová, Kateřina; Bláha, Luděk; Maršálek, Blahoslav

    2007-01-01

    Roč. 46, č. 2 (2007), s. 137-142 ISSN 0031-8884 R&D Projects: GA AV ČR(CZ) KJB6005411; GA ČR(CZ) GA206/03/1215 Grant - others:-(CZ) 1M6798593901 Institutional research plan: CEZ:AV0Z60050516 Keywords : algae * allelopathy * cyanotoxin Subject RIV: EF - Botanics Impact factor: 1.358, year: 2007

  14. Breakthrough of Oscillatoria limnetica and microcystin toxins into ...

    African Journals Online (AJOL)

    The presence of cyanobacteria and their toxins (cyanotoxins) in processed drinking water may pose a health risk to humans and animals. The efficiency of conventional drinking water treatment processes (coagulation, flocculation, rapid sand filtration and disinfection) in removing cyanobacteria and cyanotoxins varies ...

  15. Breakthrough of Oscillatoria limnetica and microcystin toxins into ...

    African Journals Online (AJOL)

    2016-01-01

    , 1996) and Serbia (Svircev et al., 2009) have been linked to drinking water containing MCs. Moreover,. Lévesque et al. (2014) documented a relationship between gastrointestinal symptoms and consumption of drinking water.

  16. Microcystis aeruginosa : source of toxic microcystins in drinking water

    African Journals Online (AJOL)

    Cyanobacteria produce two main groups of toxin namely neurotoxins and peptide hepatotoxins. They were first characterized from the unicellular species, Microcystis aeruginosa, which is the most common toxic cyanobacterium in eutrophic freshwater. The association of environmental parameters with cyanobacterial ...

  17. Microcystin-RR Like Toxin Identified in the Cyanobacterium ...

    African Journals Online (AJOL)

    a and anatoxin-a(s). Anabaena and Microcystis were reported to be responsible for the lethal poisoning of over 2000 people in Bahia, Brazil through drinking water which resulted in the death of 88 children from gastro-enteritis over a period of ...

  18. Microcystis aeruginosa : source of toxic microcystins in drinking water

    African Journals Online (AJOL)

    Cyanobacteria are one of the earth's most ancient life forms. Evidence of their existence on earth, derived from fossil records, encompasses a period of some 3.5 billion years in the late Precambrian era. Cyanobacteria are the dominant phytoplanton group in eutrophic freshwater bodies worldwide. They have caused animal ...

  19. First report of cyanobacterial diversity and microcystins in a ...

    African Journals Online (AJOL)

    The cyanobacterial diversity of Sidi Boughaba, a Moroccan coastal lagoon and Ramsar site, was evaluated and its potentially toxic species were isolated and characterised. This study was the first time that cyanobacterial diversity and cyanotoxin production have been characterised in a Moroccan coastal lagoon. Samples ...

  20. Exposure to crude microcystins via intraperitoneal injection, but not ...

    African Journals Online (AJOL)

    DR. NJ TONUKARI

    2012-06-14

    Jun 14, 2012 ... a toxin-producing cyanobacterial bloom of Microcystis spp. in Lake Taihu, leaving approximately two million people without clean drinking-water for at least one week. (Qin et al., 2010). Cyanobacterial blooms also can bring about intoxication events of aquatic animals and even humans due to the highly ...

  1. Inhibition of Microcystis aeruginosa and microcystin- LR with one ...

    African Journals Online (AJOL)

    Yomi

    Toxic Microcystis aeruginosa blooms have been increased in freshwater body in China in recent years. The discovery of algicidal bacteria has brought renewed attention in the treatment of the harmful algae blooms (HABs). In this study, one strain of algicidal bacterium number SDK2 was selected from a eutrophic lake and ...

  2. Monitoring of microcystin-LR in Luvuvhu River catchment ...

    African Journals Online (AJOL)

    user

    2011-01-17

    Jan 17, 2011 ... known to be a limiting nutrient in freshwater systems, could have contributed to no cyanobacteria blooms. Thus, the domestic ... there are massive growths of cyano- bacteria in the river, cyanotoxins are usually produced. .... slight difference in temperature change between sites. This may be attributed to the ...

  3. Rice field flora and vegetation in the provinces of Valencia and Tarragona

    Directory of Open Access Journals (Sweden)

    Carretero, J. L.

    1988-01-01

    Full Text Available Twenty nine emergent and twenty floating or submerged taxa , were found in the rice fields in Valencia and Tarragona provinces. Eleven of the se taxa, all them emergent, are alien Of introduced ones. Echinochloa oryzoides and E. oryzicola are the most important in both areas, together with Cyperus difformis and Echinochloa hispidula in Valencia. The remaining thirty eight taxa belong to the native flora. There are predominantly the emergent Scirpus maritimus, Alisma plantago-aquatica. Echinochloa crus-galli and Paspalum distichum; the floating Lemna minor and L. gibba; the submersed Potamogeton nodosus; Zannichellia palustris and Najas minor; and the macroscopical algae Chara vulgaris, Cladophora glomerata, Oedogonium capilliforme, Spirogyra spp., Pithophora oedogania and Hydrodictyon reticulatum. The flora evolution during the last years is analyzed and the present weed communities are studied. The contribution of the different phytosociological classes to the rice field weed flora is presented.

    De los 49 táxones registrados (29 emergentes y 20 flotantes o sumergidos 11 son exóticos introducidos, de los cuales los más importantes son Echinochloa oryzoides y E. oryzicolaen ambas zonas, además de Cyperus difformis y Echinochloa hispidula en Valencia, y el resto propios de la flora autóctona, predominando Scirpus maritimus, Alisma plantago-aquatica. Echinochloa crus-galli y Paspalum distichum como emergentes, Lemna minor y L. gibba como flotantes, Potamogeton nodosus, Zannichellia palustris y Najas minor como sumergidos y Chara vulgaris, Cladophora glomerata, Oedogonium capilliforme. Spirogyra spp., Pirhophora oedogonia e Hydrodictyon reticulatum como algas macroscópicas. Se analiza la evolución experimentada por la flora en los últimos años, además de estudiar las

  4. Biting midges (Diptera: Ceratopogonidae from Martín García Island, Argentina

    Directory of Open Access Journals (Sweden)

    María M Ronderos

    2011-09-01

    Full Text Available Nearly 230 species of biting midges have been recorded or described from Argentina; 38 of them are known from the Buenos Aires province and only one is cited from Martín García Island. This paper presents the results raised from six collecting trips which took place on the island during spring 2005, summer 2006 and autumn 2009. Diverse sampling sites including permanent and temporary aquatic environments were chosen, most of the ten sampling sites were ponds of diverse origin, some of these environments were covered with floating vegetation as Lemna gibba, Lemna minuscule, Salvinia biloba, Salvinia minima, Azolla filiculoides, Limnobium laevigatum, Pistia stratiotes, Spirodela intermedia, Wolffiella oblonga and Wolffia columbiana. Other sites were placed in urban and suburban areas. Adults were collected with sweep nets at sunrise and sunset and with light traps at intervals of four to five hours at night, depending on electricity availability on the island. Larvae and pupae were collected with different implements depending on characteristics of each surveyed aquatic habitat. In free standing water, they were captured with small sieves or hand pipettes and micropipettes, flotation techniques were utilized for sampling vegetated areas, free and rooted floating hydrophytes were extracted for removing insects among them. Thirteen species of Ceratopogonidae were collected, three of Atrichopogon Kieffer, three of Forcipomyia Meigen, two of Dasyhelea Kieffer, four of Culicoides Latreille, and one of Bezzia Kieffer, all representing new records from the island. Rev. Biol. Trop. 59 (3: 1183-1194. Epub 2011 September 01.Alrededor de 230 especies de ceratopogónidos han sido registradas o descritas en Argentina, 38 de ellas son conocidas para la provincia de Buenos Aires y sólo una ha sido previamente citada para la Isla Martín García. En este trabajo se presentan los resultados obtenidos a partir de muestreos realizados en seis viajes a la isla

  5. The toxicity of phthalocyanines to the aquatic plant Lemna minor (duckweed) – Testing of 31 compounds

    Czech Academy of Sciences Publication Activity Database

    Jančula, Daniel; Maršálek, Blahoslav

    2012-01-01

    Roč. 88, č. 8 (2012), s. 962-965 ISSN 0045-6535 R&D Projects: GA MPO FR-TI3/196 Institutional research plan: CEZ:AV0Z60050516 Keywords : ekotoxicity * impact * influence Subject RIV: EF - Botanics Impact factor: 3.137, year: 2012

  6. Effectiveness duckweed (Lemna minor) as an alternative native chicken feed native chicken (Gallus domesticus)

    Science.gov (United States)

    Putra, A.; Ritonga, M. Z.

    2018-02-01

    This study aimed to know the effectiveness duckweed as feed as native chicken (Gallus domesticus) on growth period (weight gain, feed intake and feed conversion). This research was conducted in Desa Telaga Jernih Kabupaten Langkat. The study was conducted in February 2017 until May 2017. This study use completely randomized design (CRD) with 4 treatments and 5 Replication, where each treatment consisting of 5 Native chickens unsexing. The treatment was used P0 = control (feed manufacturing), P1 = ration conventional with 10% duckweed, P2 = ration conventional with 20% duckweed, P3 = ration conventional with 30% duckweed. The parameters observed were weight gain, feed consumption and feed conversion. The results showed not significantly effect in body weight gain, feed consumption and feed conversion. Where the average of best weight gain on treatment P0 (control), P2 (20% duckweed), P3 (30% duckweed) and P1 (10% duckweed), average of best feed consumption in P0 (control), P2 (20% duckweed ) Of P1 (10% duckweed) and P3 (30% duckweed), P1 (10% duckweed) and P3 (30% duckweed), average of best feed conversion rate in P0 (control), P2 (20% duckweed) P1 (10% duckweed) and P3 (30% duckweed).

  7. Short-duration exposure to radiofrequency electromagnetic radiation alters the chlorophyll fluorescence of duckweeds (Lemna minor).

    Science.gov (United States)

    Senavirathna, Mudalige Don Hiranya Jayasanka; Takashi, Asaeda; Kimura, Yuichi

    2014-12-01

    Plants growing in natural environments are exposed to radiofrequency electromagnetic radiation (EMR) emitted by various communication network base stations. The environmental concentration of this radiation is increasing rapidly with the congested deployment of base stations. Although numerous scientific studies have been conducted to investigate the effects of EMR on the physiology of humans and animals, there have been few attempts to investigate the effects of EMR on plants. In this study, we attempted to evaluate the effects of EMR on photosynthesis by investigating the chlorophyll fluorescence (ChF) parameters of duckweed fronds. During the experiment, the fronds were tested with 2, 2.5, 3.5, 5.5 and 8 GHz EMR frequencies, which are not widely studied even though there is a potentially large concentration of these frequencies in the environment. The duckweed fronds were exposed to EMR for 30 min, 1 h and 24 h durations with electric field strength of 45-50 V/m for each frequency. The results indicated that exposure to EMR causes a change in the non-photochemical quenching of the duckweeds. The changes varied with the frequency of the EMR and were time-varying within a particular frequency. The temperature remained unchanged in the duckweed fronds upon exposure to EMR, which confirms that the effect is non-thermal.

  8. Influence of amino acids on the phytotoxicity of 2-benzoxazolinone on Lemna paucicostata

    Science.gov (United States)

    2-Benzoxazolinone (BOA) is a phytotoxic compound that induces strong effects on plant metabolism. BOA effects include increased membrane permeability, degradation of proteins and pigments, increased lipid peroxidation, oxidative stress and senescence induction. In this work, the effects of amino aci...

  9. The fate of the herbicide propanil in plants of the littoral zone of the Three Gorges Reservoir (TGR), China.

    Science.gov (United States)

    Chen, Zhongli; Schäffer, Andreas

    2016-10-01

    The anti-seasonal hydrology with 30m water fluctuations in the Three Gorges Reservoir (TGR) of China attracts growing environmental and ecological concerns. We investigated the biotransformation of the herbicide propanil in plants dominating in the littoral zone of the TGR by applying the 14 C-ring-labeled herbicide into non-aseptic hydroponic plant systems (Cynodon dactylon, Nelumbo nucifera and Bidens pilosa), aseptic plants (Lemna minor and Lemna gibba) and cell suspension cultures (C. dactylon and L. minor). (1) Propanil absorbed in plants of the hydroponic systems was (12.46±1.63)% of applied radioactivity (AR) (C. dactylon), (52.36±6.38)% (N. nucifera) and (76.55±6.07)% (B. pilosa), respectively. The 14 C-residues in the plant extractable fractions and the corresponding media were confirmed by radio-Thin Layer Chromatography (TLC), radio-High Performance Liquid Chromatography (HPLC) and Gas Chromatography-Electron Ionization Mass Spectrometry (GC-EIMS) as propanil, 3,4-dichloroaniline (DCA) and N-(3,4-dichlorophenyl)-β-d-glucopyranosylamine (Glu-DCA). (2) About 8% of AR was taken up by both aseptic plants, from which 7.0% of AR was extracted and identified also as propanil, DCA and Glu-DCA. (3) Concerning cell suspension cultures, (39.22±9.39)% of AR was absorbed by C. dactylon after 72hr, whereas the accumulated 14 C-propanil by L. minor cell suspension culture amounted to (65.04±1.72)% after 7days. The identified compounds in cell cultures are consistent with those in the tested plants. Most of the pesticide residues in the intact plants were un-extractable, which are recognized as the end of the detoxification process. We therefore consider these plants as suitable for the phytoremediation of the herbicide propanil in the TGR region. Copyright © 2016. Published by Elsevier B.V.

  10. Sewage treatment in integrated system of UASB reactor and duckweed pond and reuse for aquaculture.

    Science.gov (United States)

    Mohapatra, D P; Ghangrekar, M M; Mitra, A; Brar, S K

    2012-06-01

    The performance of a laboratory-scale upflow anaerobic sludge blanket (UASB) reactor and a duckweed pond containing Lemna gibba was investigated for suitability for treating effluent for use in aquaculture. While treating low-strength sewage having a chemical oxygen demand (COD) of typically less than 200 mg/L, with an increase in hydraulic retention time (HRT) from 10.04 to 33.49 h, COD removal efficiency of the UASB reactor decreased owing to a decrease in organic loading rate (OLR) causing poor mixing in the reactor. However, even at the lower OLR (0.475 kg COD/(m3 x d)), the UASB reactor gave a removal efficiency of 68% for COD and 74% for biochemical oxygen demand (BOD). The maximum COD, BOD, ammonia-nitrogen and phosphate removal efficiencies of the duckweed pond were 40.77%, 38.01%, 61.87% and 88.57%, respectively. Decreasing the OLR by increasing the HRT resulted in an increase in efficiency of the duckweed pond for removal of ammonia-nitrogen and phosphate. The OLR of 0.005 kg COD/(m2 x d) and HRT of 108 h in the duckweed pond satisfied aquaculture quality requirements. A specific growth rate of 0.23% was observed for tilapia fish fed with duckweed harvested from the duckweed pond. The economic analysis proved that it was beneficial to use the integrated system of a UASB reactor and a duckweed pond for treatment of sewage.

  11. Development and validation of phytotoxicity tests with emergent and submerged aquatic plants

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, J.S. [Carolina Ecotox, Inc., Durham, NC (United States); Powell, R.L. [Monsanto Co., St. Louis, MO (United States); Nelson, M.K. [National Biological Service, Columbia, MO (United States)

    1995-12-31

    Toxicity testing procedures have recently been developed for assessment of contaminant effects on emergent and submerged aquatic macrophytes commonly found in freshwater wetlands. These tests have potential application in risk assessments for contaminated wetlands as well as for new chemical substances. The objective of this study was to evaluate and modify, if necessary, these methods and to validate them, using two benchmark chemicals, in a contract laboratory setting. Oryza sativa (domestic rice) was used as a surrogate emergent vascular plant, while Ceratophylium demersum (coontail) and Myriophyllum heterophyllum (variable-leaf milfoil) were the representative submerged vascular plants. Subsequent to evaluating culturing techniques and testing conditions, toxicity tests were conducted using boron and metribuzin. The test procedure for the emergent plants involves a two-week pro-exposure period followed by a two-week aqueous exposure. Five types of sediment, including both natural and artificial sediments, were evaluated for use with rice. Fresh weight and chlorophyll a content were the selected test endpoints. The submerged plants were exposed for two weeks, and the response variables evaluated included length, weight (fresh and dry), and root number. The sensitivity of these tests were comparable to the results obtained for the same two chemicals using the green alga, Selenastrum capricornutum, and the duckweed, Lemna gibba, with the exception that rice was less sensitive to metribuzin than the other species.

  12. Potential of some aquatic plants for removal of arsenic from wastewater by green technology

    Directory of Open Access Journals (Sweden)

    Mohammed Barznji Dana A.

    2015-03-01

    Full Text Available Phytoremediation or green technology is counted among the successful and effective biological contaminated water treatment techniques. Basically, the concept of this green, cost-effective, simple, environmentally nondisruptive method consists in using plants and microbiological processes to reduce contaminants in the ecosystem. Different species from aquatic plants (emerged, free-floating, and submerged have been studied to mitigate toxic contaminants such as arsenic, cadmium, chromium, copper, lead, mercury, zinc, etc. Arsenic is one of the most severe toxic elements; it is widely distributed in the environment, usually found in combination with chloride, oxygen, sulphur and metal ions as a result of mineral dissolution from sedimentary or volcanic rocks and the dilution of geothermal water. The effluents from both industrial and agricultural sectors are also regarded as sources to contaminate water. From the accumulation point of view, several aquatic plants have been mentioned as good arsenic accumulators and their performance is evaluated using the green technology method. These include Spirodela polyrhiza, Wolffia globosa, Lemna gibba, L. minor, Eichhornia crassipes, Azolla caroliniana, Azolla filiculoides, Azolla pinnata, Ceratophyllum demersum and Pistia stratiotes. The up-to-date information illustrated in this review paper generates knowledge about the ability of some common aquatic plants around the globe to remediate arsenic from contaminated water.

  13. The transcriptome of Utricularia vulgaris, a rootless plant with minimalist genome, reveals extreme alternative splicing and only moderate sequence similarity with Utricularia gibba

    Czech Academy of Sciences Publication Activity Database

    Bárta, J.; Stone, James D.; Pech, J.; Sirová, D.; Adamec, Lubomír; Campbell, M. A.; Štorchová, H.

    2015-01-01

    Roč. 15, MAR 7 (2015), s. 1-14, no. 78 ISSN 1471-2229 R&D Projects: GA ČR(CZ) GAP504/11/0783 Institutional support: RVO:67985939 Keywords : transcriptome * root-associated genes * alternative splicing Subject RIV: EF - Botanics Impact factor: 3.631, year: 2015

  14. The transcriptome of Utricularia vulgaris, a rootless plant with minimalist genome, reveals extreme alternative splicing and only moderate sequence similarity with Utricularia gibba

    Czech Academy of Sciences Publication Activity Database

    Bárta, J.; Stone, James D.; Pech, J.; Sirová, D.; Adamec, L.; Campbell, M. A.; Štorchová, Helena

    2015-01-01

    Roč. 15, MAR 7 2015 (2015) ISSN 1471-2229 R&D Projects: GA ČR(CZ) GAP504/11/0783 Institutional support: RVO:61389030 Keywords : Transcriptome * Root-associated genes * Alternative splicing Subject RIV: EF - Botanics Impact factor: 3.631, year: 2015

  15. Microcystin quota, cell division and microcystin net production of precultured Microcystis aeruginosa CYA 228 (Chroococcales, Cyanophyceae) under field conditions

    DEFF Research Database (Denmark)

    Lyck, S.; Christoffersen, K.

    2003-01-01

    compared with previous data obtained from batch cultures. Growth of an easily recognizable unicellular culture alga in the field made it possible to evaluate different ways of expressing mcyst field data as the ratio of mcyst to dry weight, protein or chlorophyll a (Chl a) against the mcyst quota...... the present experiment support the hypothesis of a constitutive mcyst net production. The average Q(mcyst) of cells grown under field conditions was 85.7 +/- 43.6 ((x) over bar +/- s) fg mcyst cell(-1) compared to the average of 278 +/- 115 ((x) over bar +/- s) fg mcyst cell(-1) found previously under...... or mcyst: protein ratios in the field....

  16. Comparative phytotoxicity of methylated and inorganic arsenic- and antimony species to Lemna minor, Wolffia arrhiza and Selenastrum capricornutum

    NARCIS (Netherlands)

    Duester, L.; van der Geest, H.G.; Moelleken, S.; Hirner, A.V.; Kueppers, K.

    2011-01-01

    The alkylation of metalloids through the transfer of methyl groups is an important factor in the biogeochemical cycling of elements like arsenic and antimony. In the environment, many different organic and inorganic forms of these elements can therefore be found in soils, sediments or organisms.

  17. Utilizing Anaerobically Digested Dairy Manure for the Cultivation of Duckweed for Biomass Production, Nutrient Assimilation, and Sugar Production

    Science.gov (United States)

    Kruger, Kevin C.

    Nutrient management methods are needed to provide sustainable operation to livestock production that balance the costs of operation and maintenance. Cultivating duckweed on dairy wastes is considered an effective way of nutrient uptake and cycling. Duckweed cultivation has been implemented on nutrient management systems, such as constructed wetlands and waste stabilization ponds that use both domestic and swine wastewater. The objectives of this study were to (1) identify a nutrient concentration and duckweed strain that rapidly produces biomass, (2) removes nutrient content from anaerobically digested dairy manure, and (3) produces starch from nutrient starvation. To complete these objectives, this study targeted estimating growth and nutrient rate constants as well as starch yield of duckweed under different cultivation conditions. The strains of duckweed, Landoltia punctata 0128, Lemna gibba 7589, and Lemna minuta 9517 were identified as the promising candidates for their high levels of nutrient uptake, starch accumulation, and biomass production. The growth rate of the duckweed strain was assessed based on the effects of temperature, pH, dissolved oxygen, light intensity, nutrient concentration, and biomass accumulation. The nutrient uptake through duckweed cultivation on the anaerobically digested (AD) dairy manure, characterized by the changes of total nitrogen (TN), total Kjeldahl nitrogen (TKN), total phosphorus (TP), and ortho-phosphate-phosphorus (o-PO 4-P), was assessed in four nutrient dilution ratios 1:5, 1:13, 1:18, and 1:27 v/v at two light intensities of 10,000 and 3,000 lux to model seasonal variation. The duckweed strain that exhibited the best biomass production, nutrient removal and starch accumulation was Landoltia punctata 0128 at a dilution ratio of 1:27 at a light intensity of 10,000 lux. The growth rate constant established from zero order kinetics for Landoltia punctata 0128 was 13.3 gm-2d-1. The rate constants for nutrient recovery were 0

  18. Optimization of methodology by X-ray fluorescence for the metals determination in aquatic plants of the high course of the Lerma river

    International Nuclear Information System (INIS)

    Albino P, E.

    2015-01-01

    The high course of the Lerma river has a pollution problem in its hydrological system due to discharges of urban wastewater and industrial areas; the pollutants that affect the hydrological system are metals, which are absorbed by living organisms and probably incorporated into the food chain. For this reason in this work the technique of X-ray fluorescence total reflection was applied in six species of aquatic plants that grow in the high course of the Lerma river: Arroyo Mezapa (Eichhornia crassipes, Juncus efusus, Hydrocotyle, Schoenoplectus validus) Ameyalco river (Lemna gibba) and Atarasquillo river (Berula erecta) in order to evaluate the metals concentration (Cr, Mn, Fe, Ni, Cu, Zn and Pb) as well as the translocation factor and bioaccumulation factor for each aquatic species. According to the results, was observed that the highest concentration of metals is located in the deeper parts; metals which present a significant concentration are Mn and Fe in the six species of aquatic plants. According to the translocation factor the species having a higher translocation of metals are: Juncus efusus in Mn (1.19 mg/L) and Zn (1.31 mg/L), Hydrocotyle (1.14 mg/L), the species Eichhornia crassipes not show translocation. For bioaccumulation factor, was observed that the most bioaccumulation of metals is found in the soluble fraction of the six species of aquatic plants, especially Fe followed of Cu and Zn. Also was considered that the Berula erecta plant had a higher bioaccumulation of metals such as Cr, Mn, Fe, Cu and Zn so it can be considered as a hyper-accumulating species of these elements. With the results can be considered that the technique of X-ray fluorescence total reflection is 95% reliable to determine the concentration of metals within the structures of the aquatic plants used for this study. (Author)

  19. Haloacetic acids in the aquatic environment. Part II: ecological risk assessment

    International Nuclear Information System (INIS)

    Hanson, Mark L.; Solomon, Keith R.

    2004-01-01

    Haloacetic acids (HAAs) are environmental contaminants found in aquatic ecosystems throughout the world as a result of both anthropogenic and natural production. The ecological risk posed by these compounds to organisms in freshwater environments, with a specific focus on aquatic macrophytes, was characterized. The plants evaluated were Lemna gibba, Myriophyllum spicatum and M. sibiricum and the HAAs screened were monochloroacetic acid (MCA), dichloroacetic acid (DCA), trichloroacetic acid (TCA), trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA). Laboratory toxicity data formed the basis of the risk assessment, but field studies were also utilized. The estimated risk was calculated using hazard quotients (HQ), as well as effect measure distributions (EMD) in a modified probabilistic ecological risk assessment. EMDs were used to estimate HAA thresholds of toxicity for use in HQ assessments. This threshold was found to be a more sensitive measure of low toxicity than the no observed effect concentrations (NOEC) or the effective concentration (EC 10 ). Using both deterministic and probabilistic methods, it was found that HAAs do not pose a significant risk to freshwater macrophytes at current environmental concentrations in Canada, Europe or Africa for both single compound and mixture exposures. Still, HAAs are generally found as mixtures and their potential interactions are not fully understood, rendering this phase of the assessment uncertain and justifying further effects characterization. TCA in some environments poses a slight risk to phytoplankton and future concentrations of TFA and CDFA are likely to increase due to their recalcitrant nature, warranting continued environmental surveillance of HAAs. - Current environmental concentrations of haloacetic acids do not pose a risk to aquatic macrophytes, but could impact plankton

  20. Optimization of methodology by X-ray fluorescence for the metals determination in aquatic plants of the high course of the Lerma river; Optimizacion de la metodologia por fluorescencia de rayos X para la determinacion de metales en plantas acuaticas del curso alto del Rio Lerma

    Energy Technology Data Exchange (ETDEWEB)

    Albino P, E.

    2015-07-01

    The high course of the Lerma river has a pollution problem in its hydrological system due to discharges of urban wastewater and industrial areas; the pollutants that affect the hydrological system are metals, which are absorbed by living organisms and probably incorporated into the food chain. For this reason in this work the technique of X-ray fluorescence total reflection was applied in six species of aquatic plants that grow in the high course of the Lerma river: Arroyo Mezapa (Eichhornia crassipes, Juncus efusus, Hydrocotyle, Schoenoplectus validus) Ameyalco river (Lemna gibba) and Atarasquillo river (Berula erecta) in order to evaluate the metals concentration (Cr, Mn, Fe, Ni, Cu, Zn and Pb) as well as the translocation factor and bioaccumulation factor for each aquatic species. According to the results, was observed that the highest concentration of metals is located in the deeper parts; metals which present a significant concentration are Mn and Fe in the six species of aquatic plants. According to the translocation factor the species having a higher translocation of metals are: Juncus efusus in Mn (1.19 mg/L) and Zn (1.31 mg/L), Hydrocotyle (1.14 mg/L), the species Eichhornia crassipes not show translocation. For bioaccumulation factor, was observed that the most bioaccumulation of metals is found in the soluble fraction of the six species of aquatic plants, especially Fe followed of Cu and Zn. Also was considered that the Berula erecta plant had a higher bioaccumulation of metals such as Cr, Mn, Fe, Cu and Zn so it can be considered as a hyper-accumulating species of these elements. With the results can be considered that the technique of X-ray fluorescence total reflection is 95% reliable to determine the concentration of metals within the structures of the aquatic plants used for this study. (Author)

  1. Toxicity of trifluoroacetate to aquatic organisms

    Energy Technology Data Exchange (ETDEWEB)

    Berends, A.G.; Rooij, C.G. de [Solvay S.A., Brussels (Belgium); Boutonnet, J.C. [Elf Atochem, Levallois-Perret (France); Thompson, R.S. [Zeneca Ltd., Devon (United Kingdom). Brixham Environmental Lab.

    1999-05-01

    As a result of the atmospheric degradation of several hydrofluorocarbons and hydrochlorofluorocarbons, trifluoroacetate (TFA) will be formed. Through precipitation, TFA will enter aquatic ecosystems. To evaluate the impact on the aquatic environment, an aquatic toxicity testing program was carried out with sodium trifluoroacetate (NaTFA). During acute toxicity tests, no effects of NaTFA on water fleas (Daphnia magna) and zebra fish (Danio retrio) were found at a concentration of 1,200 mg/L. A 7-d study with duckweed (Lemna gibba Ge) revealed a NOEC of 300 mg/L. On the basis of the results of five toxicity tests with Selenastrum capricornutum, they determined a NOEC of 0.12 mg/L. However, algal toxicity tests with NaTFA and Chlorella vulgaris, Scenedesmus subspicatus, Chlamydomonas reinhardtii, Dunaliella tertiolecta, Eugelan gracilis, Phaeodactylum tricornutum, Navicula pelliculosa, Skeletonema costatum, Anabaena flos-aquae, and Microcystis aeruginosa resulted in EC50 values that were all higher than 100 mg/L. The toxicity of TFA to S. capricornutum could be due to metabolic defluorination to monofluoroacetate (MFA), which is known to inhibit the citric acid cycle. A toxicity test with MFA and S. capricornutum revealed it to be about three orders of magnitude more toxic than TFA. However, a bioactivation study revealed that defluorination of TFA was less than 4%. On the other hand, S. capricornutum exposed to a toxic concentration of NaTFA showed a recovery of growth when citric acid was added, suggesting that TFA (or a metabolite of TFA) interferes with the citric acid cycle. A recovery of the growth of S. capricornutum was also found when TFA was removed from the test solutions. Therefore, TFA should be considered algistatic and not algicidic for S. capricornutum. On the basis of the combined results of the laboratory tests and a previously reported semi-field study, they can consider a TFA concentration of 0.10 mg/L as safe for the aquatic ecosystem.

  2. Lake Erie, phosphorus and microcystin: Is it really the farmer's fault?

    Science.gov (United States)

    Agricultural loss of phosphorus (P) have been identified as a primary contributor to eutrophication and the associated release of toxins (i.e., mycrocystin) in Lake Erie. These losses are commonly deemed excessive by the media and the public, singling out agriculture as the culprit in spite of redu...

  3. Controlling toxic cyanobacteria: Effects of dredging and phosphorus-binding clay on cyanobacteria and microcystins

    NARCIS (Netherlands)

    Lürling, M.; Faassen, E.J.

    2012-01-01

    Sediment dredging and Phoslock® addition were applied individually and in combination in an enclosure experiment in a Dutch hypertrophic urban pond. These measures were applied to control eutrophication and reduce the risk of exposure to cyanobacterial toxins. Over the 58 days course of the

  4. Summer changes in cyanobacterial bloom composition and microcystin concentration in eutrophic Czech reservoirs

    Czech Academy of Sciences Publication Activity Database

    Znachor, Petr; Jurczak, T.; Komárková, Jaroslava; Jezberová, Jitka; Mankiewicz, J.; Kaštovská, Klára; Zapomělová, E.

    2006-01-01

    Roč. 21, č. 3 (2006), s. 236-243 ISSN 1520-4081 R&D Projects: GA AV ČR(CZ) IBS6017004; GA ČR(CZ) GP206/03/P024 Grant - others:EC(XE) EVK2-1999-00213 Institutional research plan: CEZ:AV0Z60170517 Keywords : cyanobacteria l blooms * mycrocystins * reservoirs Subject RIV: DA - Hydrology ; Limnology Impact factor: 1.582, year: 2006

  5. Microcystin-Bound Protein Patterns in Different Cultures of Microcystis aeruginosa and Field Samples.

    Science.gov (United States)

    Wei, Nian; Hu, Lili; Song, Lirong; Gan, Nanqin

    2016-10-12

    Micocystin (MC) exists in Microcystis cells in two different forms, free and protein-bound. We examined the dynamic change in extracellular free MCs, intracellular free MCs and protein-bound MCs in both batch cultures and semi-continuous cultures, using high performance liquid chromatography and Western blot. The results showed that the free MC per cell remained constant, while the quantity of protein-bound MCs increased with the growth of Microcystis cells in both kinds of culture. Significant changes in the dominant MC-bound proteins occurred in the late exponential growth phase of batch cultures, while the dominant MC-bound proteins in semi-continuous cultures remained the same. In field samples collected at different months in Lake Taihu, the dominant MC-bound proteins were shown to be similar, but the amount of protein-bound MC varied and correlated with the intracellular MC content. We identified MC-bound proteins by two-dimensional electrophoresis immunoblots and mass spectrometry. The 60 kDa chaperonin GroEL was a prominent MC-bound protein. Three essential glycolytic enzymes and ATP synthase alpha subunit were also major targets of MC-binding, which might contribute to sustained growth in semi-continuous culture. Our results indicate that protein-bound MC may be important for sustaining growth and adaptation of Microcystis sp.

  6. Immunomodulatory Potency of Microcystin, an Important Water-Polluting Cyanobacterial Toxin

    Czech Academy of Sciences Publication Activity Database

    Adamovský, O.; Moosová, Z.; Pekarová, Michaela; Basu, A.; Babica, P.; Šindlerová, Lenka; Kubala, Lukáš; Blaha, L.

    2015-01-01

    Roč. 49, č. 20 (2015), s. 12457-12464 ISSN 0013-936X Institutional support: RVO:68081707 Keywords : NF-KAPPA-B * NECROSIS-FACTOR-ALPHA * TOLL-LIKE RECEPTORS Subject RIV: BO - Biophysics Impact factor: 5.393, year: 2015

  7. Detoxification and oxidative stress responses along with microcystins accumulation in Japanese quail exposed to cyanobacterial biomass

    Czech Academy of Sciences Publication Activity Database

    Pašková, Veronika; Adamovský, Ondřej; Pikula, J.; Skočovská, B.; Bandouchová, H.; Horáková, J.; Babica, Pavel; Maršálek, Blahoslav; Hilscherová, Klára

    2008-01-01

    Roč. 398, 1-3 (2008), s. 34-47 ISSN 0048-9697 Institutional research plan: CEZ:AV0Z60050516 Keywords : cyanobacteria * detoxification * quails Subject RIV: EF - Botanics Impact factor: 2.579, year: 2008

  8. Studies on the water quality and biota of a tidal eutrophic creek ...

    African Journals Online (AJOL)

    ... E.monodon, Navicula gracilis, N. mutica, Ulnariaulna, Nitzschia palea, Pinnularia braunii, P. gibba, Microcystis aeruginosa and Spirulina platensis. Of the 15 mudflat algae Nitzschia palea, Pinnularia braunii, P. gibba and Spirulina platensis were environmentally important species. The population of the benthic fauna was ...

  9. Toxicity of complex cyanobacterial samples and their fractions in Xenopus laevis embryos and the role of microcystins

    Czech Academy of Sciences Publication Activity Database

    Buryšková, B.; Hilscherová, Klára; Babica, Pavel; Vršková, D.; Maršálek, Blahoslav; Bláha, Luděk

    2006-01-01

    Roč. 80, č. 4 (2006), s. 346-354 ISSN 0166-445X R&D Projects: GA MŠk 1M0571; GA AV ČR KJB6005411 Institutional research plan: CEZ:AV0Z60050516 Keywords : FETAX * Xenopus laevis * malformations * cyanobacterial fractions * biomarkers Subject RIV: EF - Botanics Impact factor: 2.964, year: 2006

  10. Impacts of Rac- and S-metolachlor on cyanobacterial cell integrity and release of microcystins at different nitrogen levels.

    Science.gov (United States)

    Wang, Jia; Zhang, Lijuan; Fan, Jiajia; Wen, Yuezhong

    2017-08-01

    Pesticide residues and nitrogen overload (which caused cyanobacteria blooms) have been two serious environmental concerns. In particular, chiral pesticides with different structures may have various impacts on cyanobacteria. Nitrogen may affect the behavior between pesticides and cyanobacteria (e.g., increase the adverse effects of pesticides on cyanobacteria). This study evaluated the impacts of Rac- and S-metolachlor on the cell integrity and toxin release of Microcystis aeruginosa cells at different nitrogen levels. The results showed that (both of the configurations: Rac-, S-) metolachlor could inhibit M. aeruginosa cell growth under most conditions, and the inhibition rates were increased with the growing concentrations of nitrogen and metolachlor. However, cyanobacterial growth was promoted in 48 h under environmental relevant condition (1 mg/L metolachlor and 0.15 mg/L nitrogen). Therefore, the water authorities should adjust the treatment parameters to remove possible larger numbers of cyaonbacteria under that condition. On the other hand, the inhibition degree of M. aeruginosa cell growth by S-metolachlor treatments was obviously larger than Rac-metolachlor treatments. S-metolachlor also had a stronger ability in compromising M. aeruginosa cells than Rac-metolachlor treatments. Compared to control samples, more extracellular toxins (12%-86% increases) were detected after 5 mg/L S-metolachlor treatment for 72 h at different nitrogen levels, but the variations of extracellular toxins caused by 5 mg/L Rac-metolachlor addition could be neglected. Consequently, higher concentrations of metolachlor in source waters are harmful to humans, but it may prevent cyanobacterial blooms. However, the potential risks (e.g. build-up of extracellular toxins) should be considered. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Life-cycle exposure to microcystin-LR interferes with the reproductive endocrine system of male zebrafish.

    Science.gov (United States)

    Su, Yujing; Li, Li; Hou, Jie; Wu, Ning; Lin, Wang; Li, Guangyu

    2016-06-01

    Recently, MC-LR reproductive toxicity drew great attention. Limited information was available on endocrine-disrupting effects of MC-LR on the reproduction system in fish. In the present study, zebrafish hatchlings (5 d post-fertilization) were exposed to 0, 0.3, 3 and 30μg/L MC-LR for 90 d until they reached sexual maturity. Male zebrafish were selected, and changes in growth and developmental parameters, testicular histological structure as well as the levels of gonadal steroid hormones were studied along with the related-gene transcriptional responses in the hypothalamic-pituitary-gonadal axis (HPG-axis). The results, for the first time, show a life cycle exposure to MC-LR causes growth inhibition, testicular damage and delayed sperm maturation. A significant decrease in T/E2 ratio indicated that MC-LR disrupted sex steroid hormones balance. The changes in transcriptional responses of HPG-axis related genes revealed that MC-LR promoted the conversion of T to E2 in circulating blood. It was also noted that vtg1 mRNA expression in the liver was up-regulated, which implied that MC-LR could induce estrogenic-like effects at environmentally relevant concentrations and long-term exposure. Our findings indicated that a life cycle exposure to MC-LR causes endocrine disruption with organic and functional damage of the testis, which might compromise the quality of life for the survivors and pose a potent threat on fish reproduction and thus population dynamics in MCs-contaminated aquatic environments. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Correction to: Dynamics of Total Microcystin LR Concentration in Three Subtropical Hydroelectric Generation Reservoirs in Uruguay, South America.

    Science.gov (United States)

    González-Piana, Mauricio; Fabián, Daniel; Piccardo, Andrea; Chalar, Guillermo

    2017-11-01

    The original version of this article contains mistakes. The author inadvertently mentioned units mg/L in all the places of first paragraph under "Results and discussion" section. The correct unit is µg/L. In second paragraph, 10th line under "Results and discussion" section, the value should read as (< 0.05-85.4 µg/mm 3 ) instead of (< 0.05-854.00 µg/mm 3 ). The units and value are corrected through this erratum.

  13. Comparative Sensor Fusion between Hyperspectral and Multispectral Remote Sensing Data for Monitoring Microcystin Distribution in Lake Erie

    Science.gov (United States)

    Urban growth and agricultural production have caused an influx of nutrients into Lake Erie, leading to eutrophic zones. These conditions result in the formation of algal blooms, some of which are toxic due to the presence of Microcystis (a cyanobacteria), which produces the hepat...

  14. Effect of different cyanobacterial biomasses and their fractions with variable microcystin content on embryonal development of carp (Cyprinus carpio L.)

    Czech Academy of Sciences Publication Activity Database

    Palíková, M.; Krejčí, R.; Hilscherová, Klára; Babica, Pavel; Navrátil, S.; Kopp, R.; Bláha, Luděk

    2007-01-01

    Roč. 81, č. 3 (2007), s. 312-318 ISSN 0166-445X R&D Projects: GA AV ČR KJB6005411 Institutional research plan: CEZ:AV0Z60050516 Keywords : cyanobacterial biomass * embryonal development * common carp Subject RIV: EF - Botanics Impact factor: 2.975, year: 2007

  15. Clitocybe splendoides H. E. Bigelow (Agaricales, Tricholomataceae, a new species for Poland

    Directory of Open Access Journals (Sweden)

    Hanna Komorowska

    2013-12-01

    Full Text Available Records of Clitocybe splendoides H. E. Bigelow, a rare fungus belonging to the species group of the C. gibba type, associated with deciduous forests, especially beech forests, collected at three localities in Poland are described.

  16. Optimization of laboratory scale production and purification of ...

    African Journals Online (AJOL)

    Microcystin content is however highly variable and optimised culture conditions are essential to produce viable yields of microcystin for purification. We describe the optimization of culture conditions and evaluation of various purification methods to enhance the yield of microcystin from laboratory scale culture.

  17. Optimization of laboratory scale production and purification of ...

    African Journals Online (AJOL)

    SERVER

    2007-11-05

    Nov 5, 2007 ... production of purified microcystin for the use as standards in analytical laboratories. Microcystin content is however highly variable and optimised culture conditions are essential to produce viable yields of microcystin for ... pigments from the toxin (Lee and Chou, 2000; Botes et al., 1982). Sephadex LH-20 ...

  18. Development of a rapid and sensitive battery of bioassays for risk assessment of cyanobacterial microcystin-LR in drinking water of rural water treatment plants, South Africa

    CSIR Research Space (South Africa)

    Oberholster, Paul J

    2009-09-01

    Full Text Available Due to the lack of toxin standards and resource limitations for wide scale use of analytical methods for e.g. high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA) in cyanobacterial toxin monitoring, it has...

  19. Visible Light-activated TiO2 photocatalytic Films; Synthesis, Characterization and Environmental Application for the Destruction of Microcystin-LR

    Science.gov (United States)

    Titanium dioxide (TiO2) photocatalysis has become one of the most effective advanced oxidation technologies (AOTs) for the treatment of persistent organic contaminants. To generate hydroxyl radicals, a non-selective, reactive oxidizing species and responsible for the oxidation of...

  20. Chromosomal Aberrations in Early Embryos of Weatherfish (Misgurnus fossilis L.) Exposed to Crude Cyanobacterial Extract and Semipurified Compound of Microcystins – a Pilot Study

    Czech Academy of Sciences Publication Activity Database

    Palíková, M.; Rábová, Marie; Krejčí, R.; Navrátil, S.; Bláha, Luděk

    2007-01-01

    Roč. 76, - (2007), S55-S60 ISSN 0001-7213 Institutional research plan: CEZ:AV0Z50450515; CEZ:AV0Z60050516 Keywords : water bloom * cyanobacteria * mortality Subject RIV: EG - Zoology Impact factor: 0.687, year: 2007

  1. Phytotoxic activity of the methanol leaves extract of Paullinia pinnata ...

    African Journals Online (AJOL)

    The activity of the extract against the growth of Lemna minor was used to investigate the phytotoxic activity. The activity of the methanol extract of P. pinnata leaves against Lemna minor increased in a dose- dependent manner and was significant at 1000 μg/ml. Therefore, the methanol leaves extract of P. pinnata exhibited ...

  2. Contribution of hot spring cyanobacteria to the mysterious deaths of Lesser Flamingos at Lake Bogoria, Kenya.

    OpenAIRE

    Ballot, A.

    2004-01-01

    Cyanobacterial mats at hot springs on the shore of the alkaline Lake Bogoria, Kenya, were investigated regarding species community and cyanobacterial toxin content. The hepatotoxins microcystin -LR, -RR, -LF and -YR, and the neurotoxin anatoxin-a were present. The mats were dominated by Phormidium terebriformis, Oscillatoria willei, Spirulina subsalsa and Synechococcus bigranulatus. The concentration of microcystins in mat samples, ranged from 221 to 845 mg microcystin-LR equiv...

  3. Unmixing the young fossil record using radiocarbon-calibrated amino-acid racemization (Gulf of Trieste, northern Adriatic Sea)

    Science.gov (United States)

    Tomašových, Adam; Gallmetzer, Ivo; Haselmair, Alex; Kaufman, Darrell S.; Vidović, Jelena; Zuschin, Martin

    2017-04-01

    Marine coastal habitats globally have been affected by eutrophication, hypoxia, habitat alteration, overfishing, and resource exploitation over recent decades. However, reconstruction of past natural ecosystem states is compromised by short-term archives and biotic surveys limited to the past decades and/or by low stratigraphic resolution of fossil assemblages in sedimentary cores due to slow sedimentation and bioturbation. In the northern Adriatic Sea, which was affected by eutrophication, algal blooms and mucilage blooms, and hypoxia during the second half of the 20th century, the composition of natural baseline states of benthic ecosystems and their responses to natural and anthropogenic disturbances over longer, centennial scales are poorly known. In this study, we evaluate the timing and forcing of past hypoxia events in the northern Adriatic Sea (Gulf of Trieste) based on the production history of the opportunistic, hypoxia-tolerant bivalve Corbula gibba, using 210Pb data, radiocarbon dating, amino acid racemization, and distribution of foraminifers in 1.5-m-thick sediment cores that capture the past 500 yr. Corbula gibba tolerates eutrophied and polluted conditions and survives seasonal hypoxic and mass mortality events affecting most of the benthic macrofauna in the northern Adriatic Sea. In the aftermath of such events, it can achieve density of thousands of individuals/1 m2 and can contribute with more than 80% of individuals to the bivalve assemblage. Unmixing the stratigraphic record of cores on the basis of 311 shells of C. gibba, we show that production of this species underwent major decadal-scale fluctuations since the 18th century, with outbreaks corresponding to density of more than 1000 individuals per square meter. A positive correlation between abundances of hypoxia-tolerant foraminifers and C. gibba, the temporal coincidence between the peak in abundance at 1980 and several hypoxic crises in the Gulf of Trieste in 1974, 1980, and 1983, and the

  4. Biosolubilization of uranyl ions in uranium ores by hydrophyte plants

    International Nuclear Information System (INIS)

    Cecal, Alexandru; Calmoi, Rodica; Melniciuc-Puica, Nicoleta

    2006-01-01

    This paper investigated the bioleaching of uranyl ions from uranium ores, in aqueous medium by hydrophyte plants: Lemna minor, Azolla caroliniana and Elodea canadensis under different experimental conditions. The oxidation of U(IV) to U(VI) species was done by the atomic oxygen generated in the photosynthesis process by the aquatic plants in the solution above uranium ores. Under identical experimental conditions, the capacity of bioleaching of uranium ores decreases according to the following series: Lemna minor > Elodea canadensis > Azolla caroliniana. The results of IR spectra suggest the possible use of Lemna minor and Elodea canadensis as a biological decontaminant of uranium containing wastewaters. (author)

  5. Decolorization of Orange G and Remazol Briliant Blue R by the white rot funfus Dichomitus squalens: Toxicological evaluation and morphological study

    Czech Academy of Sciences Publication Activity Database

    Eichlerová, Ivana; Homolka, Ladislav; Benada, Oldřich; Kofroňová, Olga; Hubálek, Tomáš; Nerud, František

    2007-01-01

    Roč. 69, - (2007), s. 795-802 ISSN 0045-6535 Institutional research plan: CEZ:AV0Z50200510 Keywords : synthetic dyes * toxicity * lemna minor Subject RIV: EE - Microbiology, Virology Impact factor: 2.739, year: 2007

  6. Holocene climatic fluctuations from Lower Brahmaputra flood plain ...

    Indian Academy of Sciences (India)

    phaea nouchali, Typha latifolia, Trapa bispinosa,. Lemna minor, Eichhornia crassipes, Utricularia flexuosa, U. exoieta, Spirodela polyrhiza, Wolffia arrhiza, Nelumbo nucifera, Myriophyllum indicum,. Ceratopteris thalictroides, Marsilea minuta, Pistia stratiotes, Salvinia oblongifolia and Azolla pinnata, respectively. However ...

  7. I popolamenti zoobentonici litorali dei fondi mobili di un sito ad elevato impatto antropico: il golfo di Manfredonia, Italia.

    OpenAIRE

    Scirocco, Tommaso; Casolino, Giovanni; Fabbrocini, Adele; D'Adamo, Raffaele

    2006-01-01

    This study was conducted on the benthic macrofauna of the Manfredonia Gulf (Adriatic sea). This site is dominated by bivalves (35%), whose dominant species was Lucunella divaricata (43%) and Corbula gibba (28%), considered as indicators of environmental instability. The most abundant species was the Ophiuroidea Amphiphopolis squamata (29.2%). Homogeneity of spatial distribution was assessed by cluster analysis.

  8. Combined and single effects of pesticide carbaryl and toxic microcystis aeruginosa on the life history of Daphnia pulicaria

    NARCIS (Netherlands)

    Cerbin, S.; Kraak, M.H.S.; de Voogt, P.; Visser, P.M.; van Donk, E.

    2010-01-01

    The combined influence of a pesticide (carbaryl) and a cyanotoxin (microcystin LR) on the life history of Daphnia pulicaria was investigated. At the beginning of the experiments animals were pulse exposed to carbaryl for 24 h and microcystins were delivered bound in Microcystis’ cells at different,

  9. Combined and single effects of pesticide carbaryl and toxic Microcystis aeruginosa on the life history of Daphnia pulicaria

    NARCIS (Netherlands)

    Cerbin, S.; Kraak, M.H.S.; De Voogt, P.; Visser, P.M.; Van Donk, E.

    2010-01-01

    The combined influence of a pesticide (carbaryl) and a cyanotoxin (microcystin LR) on the life history of Daphnia pulicaria was investigated. At the beginning of the experiments animals were pulse exposed to carbaryl for 24 h and microcystins were delivered bound in Microcystis’ cells at different,

  10. NCBI nr-aa BLAST: CBRC-TGUT-27-0001 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TGUT-27-0001 ref|YP_420821.1| Microcystin-dependent protein [Magnetospirillum magnet...icum AMB-1] dbj|BAE50262.1| Microcystin-dependent protein [Magnetospirillum magneticum AMB-1] YP_420821.1 7.2 34% ...

  11. Estimation of Ion Competition via Correlated Responsivity Offset in Linear Ion Trap Mass Spectrometry Analysis: Theory and Practical Use in the Analysis of Cyanobacterial Hepatotoxin Microcystin-LR in Extracts of Food Additives

    Czech Academy of Sciences Publication Activity Database

    Urban, J.; Hrouzek, Pavel; Štys, D.; Martens, H.

    -, Mar 2013 (2013) ISSN 2314-6133 R&D Projects: GA MŠk(CZ) ED2.1.00/03.0110 Institutional support: RVO:61388971 Keywords : LINKED-IMMUNOSORBENT-ASSAY * SIGNAL SUPPRESSION * AKAIKE INFORMATION CRITERION Subject RIV: EE - Microbiology, Virology

  12. Temporal Dynamics of the Microbial Community Composition with a Focus on Toxic Cyanobacteria and Toxin Presence during Harmful Algal Blooms in Two South German Lakes

    Directory of Open Access Journals (Sweden)

    Pia I. Scherer

    2017-12-01

    Full Text Available Bacterioplankton plays an essential role in aquatic ecosystems, and cyanobacteria are an influential part of the microbiome in many water bodies. In freshwaters used for recreational activities or drinking water, toxic cyanobacteria cause concerns due to the risk of intoxication with cyanotoxins, such as microcystins. In this study, we aimed to unmask relationships between toxicity, cyanobacterial community composition, and environmental factors. At the same time, we assessed the correlation of a genetic marker with microcystin concentration and aimed to identify the main microcystin producer. We used Illumina MiSeq sequencing to study the bacterioplankton in two recreational lakes in South Germany. We quantified a microcystin biosynthesis gene (mcyB using qPCR and linked this information with microcystin concentration to assess toxicity. Microcystin biosynthesis gene (mcyE-clone libraries were used to determine the origin of microcystin biosynthesis genes. Bloom toxicity did not alter the bacterial community composition, which was highly dynamic at the lowest taxonomic level for some phyla such as Cyanobacteria. At the OTU level, we found distinctly different degrees of temporal variation between major bacteria phyla. Cyanobacteria and Bacteroidetes showed drastic temporal changes in their community compositions, while the composition of Actinobacteria remained rather stable in both lakes. The bacterial community composition of Alpha- and Beta-proteobacteria remained stable over time in Lake Klostersee, but it showed temporal variations in Lake Bergknappweiher. The presence of potential microcystin degraders and potential algicidal bacteria amongst prevalent Bacteroidetes and Alphaproteobacteria implied a role of those co-occurring heterotrophic bacteria in cyanobacterial bloom dynamics. Comparison of both lakes studied revealed a large shared microbiome, which was shaped toward the lake specific community composition by environmental factors

  13. Are We Underestimating Benthic Cyanotoxins? Extensive Sampling Results from Spain

    Directory of Open Access Journals (Sweden)

    Enrique A. Cantoral Uriza

    2017-11-01

    Full Text Available Microcystins (MCs are potent hepatotoxins, and their presence in water bodies poses a threat to wildlife and human populations. Most of the available information refers to plankton, and much less is known about microcystins in other habitats. To broaden our understanding of the presence and environmental distribution of this group of toxins, we conducted extensive sampling throughout Spain, under a range of conditions and in distinct aquatic and terrestrial habitats. More than half of the tested strains were toxic; concentrations of the hepatotoxin were low compared with planktic communities, and the number of toxic variants identified in each sample of the Spanish strains ranged from 1–3. The presence of microcystins LF and LY (MC-LF and MC-LY in the tested samples was significant, and ranged from 21.4% to 100% of the total microcystins per strain. These strains were only detected in cyanobacteria Oscillatoriales and Nostocales. We can report, for the first time, seven new species of microcystin producers in high mountain rivers and chasmoendolithic communities. This is the first report of these species in Geitlerinema and the confirmation of Anatoxin-a in Phormidium uncinatum. Our findings show that microcystins are widespread in all habitat types, including both aerophytic and endolithic peat bogs and that it is necessary to identify all the variants of microcystins in aquatic bodies as the commonest toxins sometimes represent a very low proportion of the total.

  14. Cyanobacteria produce a high variety of hepatotoxic peptides in lichen symbiosis

    Science.gov (United States)

    Kaasalainen, Ulla; Fewer, David P.; Jokela, Jouni; Wahlsten, Matti; Sivonen, Kaarina; Rikkinen, Jouko

    2012-01-01

    Lichens are symbiotic associations between fungi and photosynthetic algae or cyanobacteria. Microcystins are potent toxins that are responsible for the poisoning of both humans and animals. These toxins are mainly associated with aquatic cyanobacterial blooms, but here we show that the cyanobacterial symbionts of terrestrial lichens from all over the world commonly produce microcystins. We screened 803 lichen specimens from five different continents for cyanobacterial toxins by amplifying a part of the gene cluster encoding the enzyme complex responsible for microcystin production and detecting toxins directly from lichen thalli. We found either the biosynthetic genes for making microcystins or the toxin itself in 12% of all analyzed lichen specimens. A plethora of different microcystins was found with over 50 chemical variants, and many of the variants detected have only rarely been reported from free-living cyanobacteria. In addition, high amounts of nodularin, up to 60 μg g−1, were detected from some lichen thalli. This microcystin analog and potent hepatotoxin has previously been known only from the aquatic bloom-forming genus Nodularia. Our results demonstrate that the production of cyanobacterial hepatotoxins in lichen symbiosis is a global phenomenon and occurs in many different lichen lineages. The very high genetic diversity of the mcyE gene and the chemical diversity of microcystins suggest that lichen symbioses may have been an important environment for diversification of these cyanobacteria. PMID:22451908

  15. Are We Underestimating Benthic Cyanotoxins? Extensive Sampling Results from Spain.

    Science.gov (United States)

    Cantoral Uriza, Enrique A; Asencio, Antonia D; Aboal, Marina

    2017-11-28

    Microcystins (MCs) are potent hepatotoxins, and their presence in water bodies poses a threat to wildlife and human populations. Most of the available information refers to plankton, and much less is known about microcystins in other habitats. To broaden our understanding of the presence and environmental distribution of this group of toxins, we conducted extensive sampling throughout Spain, under a range of conditions and in distinct aquatic and terrestrial habitats. More than half of the tested strains were toxic; concentrations of the hepatotoxin were low compared with planktic communities, and the number of toxic variants identified in each sample of the Spanish strains ranged from 1-3. The presence of microcystins LF and LY (MC-LF and MC-LY) in the tested samples was significant, and ranged from 21.4% to 100% of the total microcystins per strain. These strains were only detected in cyanobacteria Oscillatoriales and Nostocales. We can report, for the first time, seven new species of microcystin producers in high mountain rivers and chasmoendolithic communities. This is the first report of these species in Geitlerinema and the confirmation of Anatoxin-a in Phormidium uncinatum . Our findings show that microcystins are widespread in all habitat types, including both aerophytic and endolithic peat bogs and that it is necessary to identify all the variants of microcystins in aquatic bodies as the commonest toxins sometimes represent a very low proportion of the total.

  16. Assessment of cyanoprokaryote blooms and of cyanotoxins in Bulgaria in a 15-years period (2000-2015)

    Czech Academy of Sciences Publication Activity Database

    Stoyneva-Gärtner, M.; Descy, J.-P.; Latli, A.; Uzunov, B. A.; Pavlova, V. T.; Bratanova, Z.; Babica, Pavel; Maršálek, Blahoslav; Meriluoto, J.; Spoof, L.

    2017-01-01

    Roč. 8, č. 1 (2017), s. 131-152 ISSN 1947-573X Institutional support: RVO:67985939 Keywords : microcystins * cyanobacteria * Bulgaria Subject RIV: EH - Ecology, Behaviour OBOR OECD: Marine biology, freshwater biology, limnology

  17. Extract of Microcystis water bloom affects cellular differentiation in filamentous cyanobacterium Trichormus variabilis (Nostocales, Cyanobacteria)

    Czech Academy of Sciences Publication Activity Database

    Bártová, Kateřina; Hilscherová, K.; Babica, Pavel; Maršálek, Blahoslav

    2011-01-01

    Roč. 23, č. 6 (2011), s. 967-973 ISSN 0921-8971 Institutional research plan: CEZ:AV0Z60050516 Keywords : microcystin * heterocyte * akinete Subject RIV: EF - Botanics Impact factor: 2.411, year: 2011

  18. Teste colorimétrico usado para o monitoramento de microcistina em cultivo de cianobactérias e em amostras de florações ambientais do sudeste do Brasil

    OpenAIRE

    Almeida, Vanessa P.S.; Cogo, Karina; Tsai, Siu M.; Moon, David H.

    2006-01-01

    Microcystins are hepatotoxic heptapeptides produced by some cyanobacterial genera under determined physico-chemical conditions in the environment, which are responsible for the intoxication and death of animals and humans. The detection of microcystins in potable water or recreational water is not carried out routinely in the majority of Brazilian states. The protein phosphatase 1 (PP1) inhibition test is a simple, rapid and reproducible colorimetric method. The applicability of the PP1 inhib...

  19. Spatial and temporal dynamics of cyanotoxins and their relation to other water quality variables in Upper Klamath Lake, Oregon, 2007-09

    Science.gov (United States)

    Eldridge, Sara L. Caldwell; Wood, Tamara M.; Echols, Kathy R.

    2012-01-01

    Phytoplankton blooms dominated by cyanobacteria that occur annually in hypereutrophic Upper Klamath Lake, Oregon, produce microcystins at concentrations that may contribute to the decline in populations of endangered Lost River (Deltistes luxatus) and shortnose (Chasmistes brevirostris) suckers. During 2007–09, water samples were collected from Upper Klamath Lake to determine the presence and concentrations of microcystins and cylindrospermopsins and to relate the spatial and temporal occurrences of microcystins to water quality and other environmental variables. Samples were analyzed for intracellular (particulate) and extracellular (dissolved) microcystins and cylindrospermopsins using enzyme-linked immunosorbent assays (ELISA). Samples contained the highest and most variable concentrations of microcystins in 2009, the year in which an earlier and heavier Aphanizomenon flos-aquae-dominated phytoplankton bloom occurred. Concentrations were lowest in 2008 when the bloom was lighter, overall, and delayed by nearly 1 month. Microcystins occurred primarily in dissolved and large (> 63 μm) particulate forms in all years of the study, and overall, concentrations were highest at MDT (the deepest site in the study) and HDB, although HDB was sampled only in 2007 and MDT was not sampled in 2008. Comparisons among daily median total microcystin concentrations; chlorophyll a concentrations; total, dissolved, and particulate nutrient concentrations; and nutrient ratios measured in 2009 and between 2007 and 2009 indicate that microcystin concentrations generally increase following the decline of the first A. flos-aquae-dominated bloom of each season in response to an increase in bioavailable nitrogen and phosphorus. Nitrogen fixation by A. flos-aquae early in the sample season appears to provide new nitrogen for growth of toxigenic Microcystis aeruginosa, whereas, later in the season, these species appear to co-exist. Understanding the ecological interactions between these

  20. Combined and single effects of pesticide carbaryl and toxic Microcystis aeruginosa on the life history of Daphnia pulicaria

    OpenAIRE

    Cerbin, S.; Kraak, M.H.S.; De Voogt, P.; Visser, P.M.; Van Donk, E.

    2010-01-01

    The combined influence of a pesticide (carbaryl) and a cyanotoxin (microcystin LR) on the life history of Daphnia pulicaria was investigated. At the beginning of the experiments animals were pulse exposed to carbaryl for 24 h and microcystins were delivered bound in Microcystis’ cells at different, sub-lethal concentrations (chronic exposure). In order to determine the actual carbaryl concentrations in the water LC-MS/MS was used. For analyses of the cyanotoxin concentration in Daphnia’s body...

  1. Decontamination of radioactive liquid wastes by hydrophytic vegetal organisms

    International Nuclear Information System (INIS)

    Cecal, Al; Popa, K.; Potoroaca, V.; Melniciuc-Puica, N.

    2001-01-01

    Bioaccumulation of some radioactive ions from contaminated waste solutions, on hydrophytic vegetal organisms is discussed. In order to follow the distribution of radioactive ions 137 Cs + , 60 Co 2+ and 51 Cr 3+ in various cell components extracted from Spirulina platensis, Porphiridium cruentum, Scenedesmus quadricauda, Lemna minor, Elodea canadensis, Pistia stratiotes and Riccia fluitans, the plants were cultivated in radioactive solutions. The resulting complexes were extracted with acetone or acetic acid and separated chromatographically. The results show an intense activity of the polysaccharide and lipoid fractions in the bioaccumulation process. The bioaccumulation varies in the series: Spirulina > Scenedesmus > Porphiridium > Riccia > Pistia > Lemna ≥ Elodea for 137 Cs + and 60 Co 2+ ; Spirulina > Porphiridium > Scenedesmus > Riccia > Pistia > Lemna > Elodea for 51 Cr 3+ . (author)

  2. Dried duckweed and commercial feed promote adequate growth performance of tilapia fingerlings

    Directory of Open Access Journals (Sweden)

    Flávia de A. Tavares

    2008-01-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2008v21n3p91 Desempenho de alevinos de tilapia nilótica alimentados com uma  combinação de lemnas secas e ração comercial. O presente estudo  avaliou a utilização de ração comercial e lemna seca no cultivo de  alevinos de tilápias nilóticas com o objetivo de reduzir os custos de produção. Três dietas representadas por lemna seca, ração comercial  (40% proteína bruta e uma combinação de lemna seca e ração  comercial foram fornecidas a um grupo de 20 alevinos de tilápia  (Oreochromis niloticus em triplicata. Peixes com peso médio 3,2 ±  0,94g foram estocados em nove tanques-rede com volume de 1-m3 e  alimentados duas vezes ao dia durante um período de 50 dias. O peso  médio final dos alevinos alimentados com ração comercial (21,67 g e  50% ração +50% lemna seca (19,53 g não diferiram estatisticamente  (p<0,05. Paralelamente, os peixes pertencentes aos mesmos tratamentos não apresentaram diferença significativa no crescimento específico. O ganho em peso foi menor em temperaturas mais baixas ao longo do período experimental, causando um aumento significativo na conversão alimentar principalmente dos alevinos alimentados apenas com lemna seca. Além disso, a dieta composta apenas de lemna seca proporcionou o menor ganho em peso e taxa de crescimento específico. Através dos resultados obtidos, conclui-se que a lemna seca pode substituir até 50% (matéria seca 1:1 da ração  comercial (40% proteína bruta utilizada na produção de alevinos de tilápia por um período de 50 dias, sem apresentar redução no crescimento.

  3. Comparative summer dynamics of surface cyanobacterial communities in two connected lakes from the west of Ireland

    Energy Technology Data Exchange (ETDEWEB)

    Touzet, N., E-mail: touzet.nicolas@itsligo.ie [Centre for Environmental Research, Innovation and Sustainability, School of Science, Department of Environmental Science, Institute of Technology Sligo, Sligo (Ireland); McCarthy, D.; Gill, A.; Fleming, G.T.A. [Microbiology, School of Natural Sciences, National University of Ireland, Galway, Galway (Ireland)

    2016-05-15

    The eutrophication of lakes is typically associated with high biomass proliferations of potentially toxic cyanobacteria. At a regional level, the sustainable management of water resources necessitates an approach that recognises the interconnectivity of multiple water systems within river catchments. This study examined the dynamics in summer diversity of planktonic cyanobacterial communities and microcystin toxin concentrations in two inter-connected lakes from the west of Ireland prone to nutrient enrichment. DGGE analysis of 16S rRNA gene amplicons of genotype-I cyanobacteria (typically spherical) showed changes in the communities of both Lough Corrib and Ballyquirke Lough throughout the summer, and identified cyanobacterial genotypes both unique and shared to both lakes. Microcystin concentrations, estimated via the protein phosphatase 2A inhibition assay, were greater in August than in July and June in both lakes. This was concomitant to the increased occurrence of Microcystis as evidenced by DGGE band excision and subsequent sequencing and BLAST analysis. RFLP analysis of PCR amplified mcy-A/E genes clustered together the August samples of both lakes, highlighting a potential change in microcystin producers across the two lakes. Finally, the multiple factor analysis of the combined environmental data set for the two lakes highlighted the expected pattern opposing greater water temperature and chlorophyll concentration against macronutrient concentrations, but also indicated a negative relationship between microcystin concentration and cyanobacterial diversity, possibly underlining allelopathic interactions. Despite some element of connectivity, the dissimilarity in the composition of the cyanobacterial assemblages and the timing of community change in the two lakes likely were a reflexion of niche differences determined by meteorologically-forced variation in physico-chemical parameters in the two water bodies. - Highlights: • DGGE highlighted

  4. Download this PDF file

    African Journals Online (AJOL)

    USER

    2016-11-26

    Nov 26, 2016 ... unavailability of nutrients due to increased level of trace metals in the mining sites thus inducing stress. Similar decrease in plant growth in metal contaminated sites has been reported on. Cucumis sativus (Abu-Muriefah, 2008), on Lemna polyrrhiza (John et al., 2008), on Glycyrrhiza uralensis (Zheng et al.,.

  5. New xenophytes from Gran Canaria (Canary Islands, Spain), with emphasis on naturalized and (potentially) invasive species

    OpenAIRE

    Verloove, F.

    2013-01-01

    Trabajos recientes de campo en Gran Canaria han facilitado el descubrimiento de nuevas localidades para plantas vasculares no nativas. Agave attenuata, Antigonon leptopus, Atriplex nummularia, Cascabela thevetia, Cenchrus echinatus, Cuscuta campestris, Diplachne fusca subsp. uninervia, Diplotaxis tenuifolia, Dysphania anthelmintica (hasta ahora confundida con D. ambrosioides), Eclipta prostrata, Euphorbia pulcherrima, Fagopyrum esculentum, Gossypium barbadense, Lablab purpureus, Lemna minuta,...

  6. Author Details

    African Journals Online (AJOL)

    Abba, A. Vol 10, No 3 (2015) - Articles Comparative studies on the efficiency of Lemna minor L., Eicchorniacrassipes and Pistiastratiotes in the phytoremediation of refinery waste water. Abstract PDF · Vol 12, No 1 (2017) - Articles Bioaccumulation of heavy metals in Amaranthus sp. L sold at vegetable farms in Katsina ...

  7. Fertilization of Earth Ponds. III: Effects on Benthic Macro ...

    African Journals Online (AJOL)

    Throughout the inorganic and organic fertilization trials, pond 2, which was at various times treated with high phosphorus (HP) fertilizer and HCC had the most abundant macrophytes, with Elodea canadensis, Lemna mino, Glyceria fluitans and Alisma plantago-aquatica dominating, especially in the warm summer periods of ...

  8. Phytotoxic, Antibacterial and Haemagglutination activities of the ...

    African Journals Online (AJOL)

    user

    2011-01-03

    Jan 3, 2011 ... The crude methanolic extract and various fractions derived from the aerial parts of Myrsine africana were screened in vitro for possible phytotoxic, antibacterial and haemagglutination activities. Moderate phytotoxic activity (31.25 %) was observed against Lemna minor L at 1000 µg/ml by chloroform fraction.

  9. Phytotoxic, insecticidal and leishmanicidal activities of aerial parts of ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-02-22

    Feb 22, 2010 ... The aim of the present study was to explore the aerial parts of the Polygonatum verticillatum for various biological activities such as phytotoxic, insecticidal and leishmanicidal properties. Outstanding phytotoxicity was observed for the crude extract and its subsequent solvent fractions against Lemna.

  10. The Limnological Status of an Old Intermitent Pond during the Wet ...

    African Journals Online (AJOL)

    User

    2011-04-19

    Apr 19, 2011 ... coagulant (Calcium hypochlorite or alum) to the collected pond water to precipitate suspended/dirt particles before usage. Due to this and also evapotranspiration from the floating macrophytes (mainly Pistia stratiotes and Lemna minor), the pond dries out by the end of the dry season. No limnological study ...

  11. A no iso ovel po lation olymera of a ne ase ch ew rbc hain rea cS ...

    African Journals Online (AJOL)

    sunny

    Hubei Norma ed 14 December, ymerase cha mosome wa ndle PCR in i. 3' downstrea mna minor ge isolated from ch was confi ion-mediated s in the isola. Lemna minor es have be omic fragme without go nomic librar chain react y been appl al PCR metho. Inverse PC and Chen, 200 gation-mediat. Villalobos et a. 2003; Dai ...

  12. Author Details

    African Journals Online (AJOL)

    Verstraete, W. Vol 10, No 1 (2006) - Articles Bio-recovery of N and P from an anaerobic digester effluent: The potential of duckweed (Lemna minor) Abstract PDF. ISSN: 0855-4307. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners ...

  13. Author Details

    African Journals Online (AJOL)

    Frimpong, KA. Vol 10, No 1 (2006) - Articles Bio-recovery of N and P from an anaerobic digester effluent: The potential of duckweed (Lemna minor) Abstract PDF · Vol 20, No 1 (2012) - Articles N2O Emissions and Inorganic N Release Following Incorporation of Crop Residue and/ or Inorganic N Fertiliser into Soil

  14. EFFECTIVE CONCENTRATIONS OF 6 CONTAMINANTS TO LEMMA MINOR, PIMEPHALES PROMELA, DAPHNIA MAGNA, AND CERIODAPHNIA DUBIA

    Science.gov (United States)

    The research presented here resulted in EC50 and LOEC values for the contaminants copper, cadmium, diazinon, atrazine, and cyanide to the species Lemna Minor, Pimephales promelas, Daphnia magna, and Ceriodaphnia dubia. Observed values were used as benchmarks for assessing the se...

  15. The Control of Dormancy and Development in Coquillettidia perturbans (Diptera: Culicidae).

    Science.gov (United States)

    1982-01-01

    pit included: Lemna minor L. (duckweed), Azolla sp. (water- fern), Salvinia rotundifolia Willd., Ipomea aquatica Forsh (morning glory), Limnobium...copy Dean School of Medicine Uniformed Services University of the Health Sciences 4301 Jones Bridge Road Bethesda, MD 20014 1 copy Commandant Academy

  16. Performance of Stochastic and Decentralized Systems.

    Science.gov (United States)

    1988-02-11

    k-I,...,K] (4.2) Wen first prove the following lemma using the results ot ... . Lem 3.1. 1839 Lemna 4.1 where the thresh Id is given by Under...Barbara. He is now in the Ph.D. to M.D. program at the University of Miami School of Medicine . t Department of Electrical and Computer Engineering

  17. An Evaluation of the Environmental Fate and behavior of Munitions Materiel (TNT, RDX) in Soil and Plant Systems. Environmental Fate and behavior of TNT

    Science.gov (United States)

    1989-08-01

    Worthley. 1974. The Toxicity of TNT and Related Wastes to an Aquatic Flowering Plant* Lemna D2erpusilla Torr. Edgewood Arsenal, Technical Report No. EB...IFrederick, MD 21707-5012 Report (5)Frdrc.M 0-02Technical tFiles() 1 Dean School of Medicine Uniformed Services University of the Health Sciences 4301 Jones

  18. Development of a Mixed Scanning Interactive System for Decision Support.

    Science.gov (United States)

    1984-07-01

    supremum of convex functions is convex and from induction. .. . . . . . . . .. - . .- Proof of Lemna 2: Since N is convex; it is sufficient to show that M...degrees under the schools of Architecture, Law, Medicine , Nursing, Commerce, Business Administration, and Education. In addition, the College of Arts

  19. Dicty_cDB: Contig-U14063-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available |pid:none) Macrostomum lignano mRNA for piwi-... 44 0.003 EU034629_1( EU034629 |p...5 0.001 AY128524_1( AY128524 |pid:none) Stylonychia lemnae macronuclear de... 45 0.001 AM942740_1( AM942740

  20. Cyanobacteria and Cyanotoxins Occurrence and Removal from Five High-Risk Conventional Treatment Drinking Water Plants

    Directory of Open Access Journals (Sweden)

    David C. Szlag

    2015-06-01

    Full Text Available An environmental protection agency EPA expert workshop prioritized three cyanotoxins, microcystins, anatoxin-a, and cylindrospermopsin (MAC, as being important in freshwaters of the United States. This study evaluated the prevalence of potentially toxin producing cyanobacteria cell numbers relative to the presence and quantity of the MAC toxins in the context of this framework. Total and potential toxin producing cyanobacteria cell counts were conducted on weekly raw and finished water samples from utilities located in five US states. An Enzyme-Linked Immunosorbant Assay (ELISA was used to screen the raw and finished water samples for microcystins. High-pressure liquid chromatography with a photodiode array detector (HPLC/PDA verified microcystin concentrations and quantified anatoxin-a and cylindrospermopsin concentrations. Four of the five utilities experienced cyanobacterial blooms in their raw water. Raw water samples from three utilities showed detectable levels of microcystins and a fourth utility had detectable levels of both microcystin and cylindrospermopsin. No utilities had detectable concentrations of anatoxin-a. These conventional plants effectively removed the cyanobacterial cells and all finished water samples showed MAC levels below the detection limit by ELISA and HPLC/PDA.

  1. Cyanobacteria and Cyanotoxins Occurrence and Removal from Five High-Risk Conventional Treatment Drinking Water Plants

    Science.gov (United States)

    Szlag, David C.; Sinclair, James L.; Southwell, Benjamin; Westrick, Judy A.

    2015-01-01

    An environmental protection agency EPA expert workshop prioritized three cyanotoxins, microcystins, anatoxin-a, and cylindrospermopsin (MAC), as being important in freshwaters of the United States. This study evaluated the prevalence of potentially toxin producing cyanobacteria cell numbers relative to the presence and quantity of the MAC toxins in the context of this framework. Total and potential toxin producing cyanobacteria cell counts were conducted on weekly raw and finished water samples from utilities located in five US states. An Enzyme-Linked Immunosorbant Assay (ELISA) was used to screen the raw and finished water samples for microcystins. High-pressure liquid chromatography with a photodiode array detector (HPLC/PDA) verified microcystin concentrations and quantified anatoxin-a and cylindrospermopsin concentrations. Four of the five utilities experienced cyanobacterial blooms in their raw water. Raw water samples from three utilities showed detectable levels of microcystins and a fourth utility had detectable levels of both microcystin and cylindrospermopsin. No utilities had detectable concentrations of anatoxin-a. These conventional plants effectively removed the cyanobacterial cells and all finished water samples showed MAC levels below the detection limit by ELISA and HPLC/PDA. PMID:26075379

  2. Effects of Microcystis aeruginosa on life history of water flea Daphnia magna

    Science.gov (United States)

    Liu, Liping; Li, Kang; Chen, Taoying; Dai, Xilin; Jiang, Min; Diana, James S.

    2011-07-01

    Cyanobacterial blooms in eutrophic freshwater systems are a worldwide problem, creating adverse effects for many aquatic organisms by producing toxic microcystins and deteriorating water quality. In this study, microcystins (MCs) in Microcystis aeruginosa, and Daphnia magna exposed to M. aeruginosa, were analyzed by HPLC-MS, and the effects of M. aeruginosa on D. magna were investigated. When D. magna was exposed to M. aeruginosa for more than 2 h, Microcystin-LR (MC-LR) was detected. When exposed to 1.5 × 106, 3 × 106, 0.75 × 107, and 1.5 × 107 cell/mL of M. aeruginosa for 96 h, average survival of D. magna for treatments were 23.33%, 33.33%, 13.33%, 16.67%, respectively, which were significantly lower than the average 100% survival in the control group ( P feeding zooplankton, which would destroy the ecological balance of aquaculture water bodies.

  3. Isolation and Characterization of Blue Green Algae from Egyptian ...

    African Journals Online (AJOL)

    meldemellawy

    2014-02-20

    Feb 20, 2014 ... aminotransferase (AMT) domains of the mycE and ndaF genes (Jungblut et al., 2006) allowing detection of microcystin and nodularin-producing cyanobacteria. MATERIALS AND METHODS. Isolation and cultivation of blue green algae. Blue green algae had been isolated from soil of Rice field in river.

  4. Combined effects of nitrogen to phosphorus ratios and nitrogen speciation on cyanobacterial metabolite concentrations in eutrophic Midwestern USA reservoirs.

    NARCIS (Netherlands)

    Harris, T.D.; Smith, V.H.; Graham, J.L.; Van de Waal, D.B.; Tedesco, L.P.; Clercin, N.

    2016-01-01

    Recent studies have shown that the total nitrogen to total phosphorus (TN:TP) ratio and nitrogen oxidation state may have substantial effects on secondary metabolite (e.g., microcystins) production in cyanobacteria. We investigated the relationship between the water column TN:TP ratio and the

  5. Screening the toxicity and toxin content of blooms of the cyanobacterium Trichodesmium erythraeum (Ehrenberg in northeast Brasil

    Directory of Open Access Journals (Sweden)

    LAO Proença

    2009-01-01

    Full Text Available Blooms of the cyanobacterium Trichodesmium occur in massive colored patches over large areas of tropical and subtropical oceans. Recently, the interest in such events has increased given their role in major nitrogen and carbon dioxide oceanic fluxes. Trichodesmium occurs all along the Brazilian coast and patches frequently migrate towards the coast. In this paper we screen the toxicity and toxin content of Trichodesmium blooms off the coast of Bahia state. Four samples, collected from February to April 2007, were analyzed. Organisms were identified and assessed for toxicity by means of several methods. Analogues of microcystins, cylindrospermopsins and saxitoxins were analyzed using HPLC. Microcystins were also assayed through ELISA. Results showed dominance of T. erythraeum, which makes up as much as 99% of cell counts. Other organisms found in smaller quantities include the dinoflagellates Prorocentrum minimum and P. rhathymum. Extracts from all samples delayed or interrupted sea urchin larval development, but presented no acute toxicity during a mouse bioassay. Saxitoxin congeners and microcystins were present at low concentrations in all samples, occurrences that had not previously been reported in the literature. Despite our finding of saxitoxin analogues and microcystins in Trichodesmium blooms, these toxins do not represent a potential harm to human health by primary contact. We conclude, based on our results and those reported in the recent literature, which differ from results published in 1963, that although toxins are present, there is no evidence that T. erythraeum blooms represent a threat to humans.

  6. African Journal of Aquatic Science - Vol 41, No 4 (2016)

    African Journals Online (AJOL)

    Trophic ecology and persistence of invasive silver carp Hypophthalmichthys molitrix in an oligotrophic South African impoundment · EMAIL FULL TEXT EMAIL FULL ... First report of cyanobacterial diversity and microcystins in a Microcystis strain from Sidi Boughaba, a Moroccan coastal lagoon · EMAIL FULL TEXT EMAIL ...

  7. Toxicological Review of Cyanobacterial Toxins: Anatoxin-a (External Review Draft)

    Science.gov (United States)

    The National Center for Environmental Assessment has prepared the Toxicological Reviews of Cyanobacterial Toxins: Anatoxin-a, Cylindrospermopsin and Microcystins (LR, RR, YR and LA) as a series of dose-response assessments to support the health assessment of unregulated contamina...

  8. Toxicological Review of Cyanobacterial Toxins: Cylindrospermopsin (External Review Draft)

    Science.gov (United States)

    The National Center for Environmental Assessment has prepared the Toxicological Reviews of Cyanobacterial Toxins: Anatoxin-a, Cylindrospermopsin and Microcystins (LR, RR, YR and LA) as a series of dose-response assessments to support the health assessment of unregulated contamina...

  9. The Use of Ultra-Violet (UV) Light Emitting Diodes (LEDS) in an Advanced Oxidation Process (AOP) with Brilliant Blue FCF as an Indicator

    Science.gov (United States)

    2015-03-26

    Coloring Food), also referred to as Brilliant Blue FDC (Food, Drug and Cosmetic or Blue #1, relevant to its use in assessing the performance of an...of Toledo, Ohio, were advised not to use tap water due to high levels of microcystin, a toxin that originates from algae and can cause diarrhea

  10. Contribution of hot spring cyanobacteria to the mysterious deaths of Lesser Flamingos at Lake Bogoria, Kenya.

    Science.gov (United States)

    Krienitz, Lothar; Ballot, Andreas; Kotut, Kiplagat; Wiegand, Claudia; Pütz, Stephanie; Metcalf, James S; Codd, Geoffrey A; Pflugmacher, Stephan

    2003-03-01

    Cyanobacterial mats at hot springs on the shore of the alkaline Lake Bogoria, Kenya, were investigated regarding species community and cyanobacterial toxin content. The hepatotoxins microcystin-LR, -RR, -LF and -YR, and the neurotoxin anatoxin-a were present. The mats were dominated by Phormidium terebriformis, Oscillatoria willei, Spirulina subsalsa and Synechococcus bigranulatus. The concentration of microcystins in mat samples, ranged from 221 to 845 microg microcystin-LR equivalents g(-1) DW of mat. Anatoxin-a concentrations ranged from 10 to 18 microg g(-1) DW of mat. A contribution of the cyanobacterial toxins from the hot spring mats to the mass mortalities of Lesser Flamingos is suggested by: (a), the presence of hot spring cyanobacterial cells and cell fragments, and high concentrations of the cyanobacterial hepato- and neurotoxins in flamingo stomach contents and faecal pellets; (b), observations of neurological signs of bird poisoning at the lake. Cyanobacterial toxins in stomach contents, intestine and fecal pellets were 0.196 microg g(-1) fresh weight (FW) for the microcystins and 4.34 microg g(-1) FW for anatoxin-a. Intoxication with cyanobacterial toxins could occur by uptake of detached cyanobacterial cells from the mats, as the flamingos need to drink fresh or brackish water, and to wash their feathers daily, which they do in the vicinity of the hot springs, where salinity is lower than in the main body of water of the lake.

  11. Occurrence, Monitoring and Treatment of Cyanobacterial Toxins in Drinking Water

    Science.gov (United States)

    In the summer of 2014 a number of drinking water treatment plants (DWTPs) on Lake Erie supplied water samples on a monthly basis for analysis. Chlorophyll-a measurements, LC/MS/MS and ELISA techniques specific to microcystins were employed to measure potential harmful algal bloom...

  12. Polymerase chain reaction (PCR) detection of the predominant ...

    African Journals Online (AJOL)

    The aim of the present study was to assess the presence of microcystins (MCs) and identify the genotypes of MC-producing cyanobacteria in Mozambique. Polymerase chain reaction (PCR) based detection methods were used to analyze samples from three study freshwater bodies which are used as sources of drinking ...

  13. African Journal of Aquatic Science - Vol 40, No 1 (2015)

    African Journals Online (AJOL)

    First report of an Anabaena Bory strain containing microcystin-LR in a freshwater body in Africa · EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. PJ Oberholster, S Jappie, PH Cheng, AM Botha, MW Matthews, 21-36. http://dx.doi.org/10.2989/16085914.2014.993583 ...

  14. Review of toxicity of cyanobacteria in Slovakia

    Czech Academy of Sciences Publication Activity Database

    Maršálek, Blahoslav; Bláha, L.; Hindák, F.

    2000-01-01

    Roč. 55, č. 6 (2000), s. 645-652 ISSN 0006-3088 R&D Projects: GA AV ČR KSK6005114 Grant - others:VEGA project(SK) No. 5049/98 Institutional research plan: CEZ:AV0Z6005908 Keywords : cyanobacteria * microcystin * toxins * Slovakia Subject RIV: EF - Botanics Impact factor: 0.165, year: 2000

  15. Occurrence of Toxic Cyanobacterial Blooms in Rio de la Plata Estuary, Argentina: Field Study and Data Analysis

    Science.gov (United States)

    Giannuzzi, L.; Carvajal, G.; Corradini, M. G.; Araujo Andrade, C.; Echenique, R.; Andrinolo, D.

    2012-01-01

    Water samples were collected during 3 years (2004–2007) at three sampling sites in the Rio de la Plata estuary. Thirteen biological, physical, and chemical parameters were determined on the water samples. The presence of microcystin-LR in the reservoir samples, and also in domestic water samples, was confirmed and quantified. Microcystin-LR concentration ranged between 0.02 and 8.6 μg.L−1. Principal components analysis was used to identify the factors promoting cyanobacteria growth. The proliferation of cyanobacteria was accompanied by the presence of high total and fecal coliforms bacteria (>1500 MNP/100 mL), temperature ≥25°C, and total phosphorus content ≥1.24 mg·L−1. The observed fluctuating patterns of Microcystis aeruginosa, total coliforms, and Microcystin-LR were also described by probabilistic models based on the log-normal and extreme value distributions. The sampling sites were compared in terms of the distribution parameters and the probability of observing high concentrations for Microcystis aeruginosa, total coliforms, and microcystin-LR concentration. PMID:22523486

  16. Spirulina (Arthrospira): An Important Source of Nutritional and Medicinal Compounds

    OpenAIRE

    Nuhu, Abdulmumin A.

    2013-01-01

    Cyanobacteria are aquatic and photosynthetic organisms known for their rich pigments. They are extensively employed as food supplements due to their rich contents of proteins. While many species, such as Anabaena sp., produce hepatotoxins (e.g., microcystins and nodularins) and neurotoxins (such as anatoxin a), Spirulina (Arthrospira) displays anticancer and antimicrobial (antibacterial, antifungal, and antiviral) activities via the production of phycocyanin, phycocyanobilin, allophycocyanin,...

  17. Detection of various freshwater cyanobacterial toxins using ultra-performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Oehrle, Stuart A; Southwell, Ben; Westrick, Judy

    2010-05-01

    Several freshwater cyanobacteria species have the capability to produce toxic compounds, frequently referred to as cyanotoxins. The most prevalent of these cyanotoxins is microcystin LR. Recognizing the potential health risk, France, Italy, Poland, Australia, Canada, and Brazil have set either standards or guidelines for the amount of microcystin LR permissible in drinking water based on the World Health Organization guideline of one microg/L of microcystin LR. Recently, the United States Environmental Protection Agency has begun to evaluate the occurrence and health effects of cyanotoxins and their susceptibility to water treatment under the Safe Drinking Water Act through the Contaminant Candidate List (CCL). A recent update of the Contaminant Candidate List focuses research and data collection on the cyanotoxins microcystin LR, anatoxin-a, and cylindrospermopsin. Liquid Chromatography/Tandem-Mass Spectrometry (LC/MS/MS) is a powerful tool for the analysis of various analytes in a wide variety of matrices because of its sensitivity and selectivity. The use of smaller column media (sub 2 microm particles) was investigated to both improve the speed, sensitivity and resolution, and to quantify the CCL cyanotoxins, in a single analysis, using Ultra-Performance Liquid Chromatography (UPLC) combined with tandem mass spectrometry. Natural waters and spiked samples were analyzed to show proof-of-performance. The presented method was able to clearly resolve each of the cyanotoxins in less than eight minutes with specificity and high spike recoveries. Copyright 2009 Elsevier Ltd. All rights reserved.

  18. Occurrence of toxic cyanobacterial blooms in rio de la plata estuary, Argentina: field study and data analysis.

    Science.gov (United States)

    Giannuzzi, L; Carvajal, G; Corradini, M G; Araujo Andrade, C; Echenique, R; Andrinolo, D

    2012-01-01

    Water samples were collected during 3 years (2004-2007) at three sampling sites in the Rio de la Plata estuary. Thirteen biological, physical, and chemical parameters were determined on the water samples. The presence of microcystin-LR in the reservoir samples, and also in domestic water samples, was confirmed and quantified. Microcystin-LR concentration ranged between 0.02 and 8.6 μg.L(-1). Principal components analysis was used to identify the factors promoting cyanobacteria growth. The proliferation of cyanobacteria was accompanied by the presence of high total and fecal coliforms bacteria (>1500 MNP/100 mL), temperature ≥25°C, and total phosphorus content ≥1.24 mg·L(-1). The observed fluctuating patterns of Microcystis aeruginosa, total coliforms, and Microcystin-LR were also described by probabilistic models based on the log-normal and extreme value distributions. The sampling sites were compared in terms of the distribution parameters and the probability of observing high concentrations for Microcystis aeruginosa, total coliforms, and microcystin-LR concentration.

  19. Effects of cyanobacterial biomass on the Japanese quail

    Czech Academy of Sciences Publication Activity Database

    Skočovská, B.; Hilscherová, Klára; Babica, Pavel; Adamovský, Ondřej; Bandouchová, H.; Horáková, J.; Knotková, Z.; Maršálek, Blahoslav; Pašková, Veronika; Pikula, J.

    2007-01-01

    Roč. 49, č. 6 (2007), s. 793-803 ISSN 0041-0101 Grant - others:-(CZ) 1M6798593901 Institutional research plan: CEZ:AV0Z60050516 Keywords : Cyanobacterial water bloom * Avian toxicity tests * Microcystins Subject RIV: EF - Botanics Impact factor: 2.246, year: 2007

  20. The effect of hydrodynamics on nitrogen accumulation and ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-07-18

    Jul 18, 2008 ... Over-producing reactive oxygen species in plant can cause oxidative damage to proteins, DNA and lipids ..... loss of pigments along with the whole period of this experiment, except in S flume of the second day. The .... cyanobacterial toxin microcystin-LR. Aquat. Toxicol. 70(3): 169-178. Romero-Puertas MC ...