Saxitoxins (STXs) are potent neurotoxins produced by marine dinoflagellates or freshwater cyanobacteria known to cause acute and eventually fatal human intoxications, which are classified as paralytic shellfish poisonings (PSPs). Rapid analysis of STXs in blood plasma can be used for a timely diagnosis and confirmation of PSPs. We developed a fast and simple method of STX extraction based on plasma sample acidification and precipitation by acetonitrile, followed by quantification using liquid chromatography-tandem mass spectrometry (LC-MS-MS). Our approach provides the results ≤30 min, with a limit of detection of 2.8 ng/mL and a lower limit of quantification of 5.0 ng/mL. Within-run and between-run precision experiments showed good reproducibility with ≤15% values. Standard curves for calibration were linear with correlation coefficients ≥0.98 across the assay calibration range (5-200 ng/mL). In an interlaboratory analytical exercise, the method was found to be 100% accurate in determining the presence or absence of STX in human plasma specimens, with recovery values of 86-99%. This simple method for STX determination in animal or human plasma can quickly and reliably diagnose STX exposures and confirm suspected PSP cases to facilitate patient treatment or expedite necessary public health or security actions.
Due to specific physical properties, hydrodynamic cavitation (HC) is assigned to the powerful technologies for treating the biotic contamination in water including cyanobacteria. Contaminated water stream (CWS) can be cavitated directly by passing through some HC device, or indirectly when high-pressure jet stream (HPJS) is directed against its flow. Relatively small HPJS stream can thus treat a big volume of CWS in a short time or even work in continuous mode. Cyanobacteria floating in the CWS are forced to flow through the mixing cavitation zone. Within 2 h after single HC treatment, cyanobacterial cell suspensions showed disintegration of larger colonies and enhanced biomass sedimentation. Additional pre-treatment of CWS with low amounts of hydrogen peroxide (H2O2; 33, 66 and 99 μmol/L) enhanced the effect of HC and led to further inhibition of cyanobacterial photosynthesis (maximum quantum yield of photosystem II decreased by up to 60%). The number of cyanobacterial cells in the treated CWS decreased continuously over 48 and 72 h, though some cells remained alive and were able to recover photosynthetic activity. The technique proposed (direction of a HPJS against a CWS and pre-treatment with low H2O2 concentrations) provides (i) effective removal of cells from the water column, and (ii) reduced contamination by organic compounds released from the cells (especially cyanotoxins) as the cell membranes are not destroyed and the cells remain alive. This process shows potential as an effective pre-treatment step in water purification processes related to cyanobacterial contamination.
- MeSH
- čištění vody * MeSH
- hydrodynamika MeSH
- organické látky MeSH
- peroxid vodíku MeSH
- sinice * MeSH
- Publikační typ
- časopisecké články MeSH
Graphene oxide (GO) as the most studied hydrophilic graphene derivative can be deployed in a broad spectrum of environmental technologies opening the issue of its ecotoxicity. Nevertheless, the information about its behavior in complex aquatic environment is still not sufficient. Here, we studied the interaction of three differently oxidized GO systems with planktonic and benthic crustaceans. By standard toxicity tests, we observed the importance of feeding strategy as well as the surface oxidation of GO with respect to GO's ecotoxicity. However, to gain a clearer insight into GO's environmental fate, we introduced a pre-treatment with algae as the most common source of food for crustaceans. Such an adjustment mimicking the conditions in real aquatic ecosystems resulted in complete mitigation of acute toxicity of GOs to all organisms and, more importantly, to the eradication of oxidative stress caused by GOs. We argue, that the pre-exposition of food is a crucial factor in GO's overall environmental fate, even though this fact has been completely neglected in recent studies. These experiments proved that GO is not a hazardous material in complex aquatic environments because its acute toxicity can be successfully mitigated through the interaction with algae even at very high concentrations (25 mg/L).
- MeSH
- chemické látky znečišťující vodu * toxicita MeSH
- ekosystém MeSH
- grafit * toxicita MeSH
- plankton MeSH
- testy toxicity MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In recent years, antibiotics have been used for human and animal disease treatment, growth promotion, and prophylaxis, and their consumption is rising worldwide. Antibiotics are often not fully metabolized by the body and are released into the aquatic environment, where they may have negative effects on the non-target species. This review examines the recent researches on eight representative antibiotics (erythromycin, trimethoprim, sulfamethoxazole, tetracycline, oxytetracycline, ofloxacin, ciprofloxacin, and amoxicillin). A detailed overview of their concentrations in surface waters, groundwater, and effluents is provided, supported by recent global human consumption and veterinary use data. Furthermore, we review the ecotoxicity of these antibiotics towards different groups of organisms, and assessment of the environmental risks to aquatic organisms. This review discusses and compares the suitability of currently used ecotoxicological bioassays, and identifies the knowledge gaps and future challenges. The risk data indicate that selected antibiotics may pose a threat to aquatic environments. Cyanobacteria were the most sensitive organisms when using standard ecotoxicological bioassays. Further studies on their chronic effects to aquatic organisms and the toxicity of antibiotic mixtures are necessary to fully understand the hazards these antibiotics present.
- MeSH
- amoxicilin MeSH
- antibakteriální látky analýza toxicita MeSH
- chemické látky znečišťující vodu analýza toxicita MeSH
- ciprofloxacin MeSH
- ekotoxikologie MeSH
- erythromycin MeSH
- hodnocení rizik MeSH
- monitorování životního prostředí * MeSH
- podzemní voda MeSH
- sulfamethoxazol MeSH
- tetracyklin MeSH
- trimethoprim analýza MeSH
- vodní organismy MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Calibrated adsorption-based passive samplers were used for time-integrative monitoring of microcystins (MCs) in three full-scale drinking water treatment plants (DWTPs) in the Czech Republic during two vegetation seasons (Jun-Nov), in parallel with traditional discrete sampling. MCs were detected in epilimnetic water samples at concentrations up to 14 μg/L, but their levels in raw water in DWTPs were below 1 μg/L WHO guideline value for drinking water. Conventional treatment technologies (coagulation/filtration) eliminated cyanobacteria and intracellular toxins but had a limited removal efficiency for extracellular toxins. MCs were regularly detected in final treated water, especially in DWTPs equipped only with the conventional treatment, but their concentrations were below the quantitation limit of discrete sampling (<25 ng/L). Passive samplers in combination with LC-MS/MS analysis provided excellent sensitivity allowing to detect time-weighted average (TWA) concentrations of MCs as low as 20-200 pg/L after 14-d deployment. Median MC TWA concentrations in the treated water from the individual DWTPs were 1-12 ng/L, and most likely did not present significant health risks. Passive samplers well reflected spatiotemporal variations of MCs, actual concentrations of extracellular toxins, MC removal efficiency in DWTPs, and toxin concentrations in the treated water. Passive sampling can be effectively used for assessment and management of MC health risks during DWTP operation.
- MeSH
- bakteriální toxiny MeSH
- chromatografie kapalinová MeSH
- čištění vody * MeSH
- mikrocystiny MeSH
- monitorování životního prostředí MeSH
- mořské toxiny MeSH
- pitná voda * MeSH
- tandemová hmotnostní spektrometrie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
- Publikační typ
- abstrakt z konference MeSH
OBJECTIVES: The aim of this study was to establish and evaluate the mortality rate, hatching rate and observe the presence of sublethal changes in zebrafish embryos after exposure to silver ions and nanoparticles. METHODS: Tests were conducted on newly fertilized zebrafish embryos, according to the modified OECD guideline 236, using a semistatic method and 96 hour incubation time. Silver nitrate and two different silver nanoparticles, stabilized with 0.01% solution of maltose and gelatine in the first case, and stabilized with polyvinylpyrrolidone, in the latter, were tested. RESULTS: Significant differences in toxicity of tested substances were recorded. The value of 96hLC50 for silver nitrate was 58.44 μg/L. The value of 96hLC50, calculated for silver nanoparticles stabilized with 0.01% solution of maltose and gelatine, was nearly 100 times higher, 4.31 mg/L. The value 96hLC50 for silver nanoparticles stabilized with polyvinylpyrrolidone exceeded 100mg/L, occurrence of sublethal effects caused by silver nanoparticles stabilized with polyvinylpyrrolidone was insignificant in most of the exposition groups, but only in this substance caused decreased hatching rate. CONCLUSION: Properties of different silver nanoparticles play an important role in levels of their toxicity and predominant mechanisms of action. In general, silver nanoparticles are less toxic for Danio rerio embryos than silver ions.
- MeSH
- dánio pruhované MeSH
- dusičnan stříbrný toxicita MeSH
- embryo nesavčí účinky léků MeSH
- LD50 MeSH
- maltosa MeSH
- nanočástice * MeSH
- povidon MeSH
- stříbro toxicita MeSH
- želatina MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Toxic cyanobacterial blooms are a global threat to human health and aquatic biota. While the ecotoxicity of cyanobacterial toxins such as microcystins has been studied extensively, little is known about the risks they pose in the wild, i.e. within complex biomasses. In this work, crustaceans (Daphnia magna) were exposed to varying concentrations (0-405 mg d.w L(-1)) of eight complex cyanobacterial water bloom samples in a series of acute (48 h) and chronic (21 day) toxicity experiments. Further acute and chronic exposure assays were performed using aqueous extracts of the crude biomass samples and two fractions prepared by solid phase extraction (SPE) of the aqueous extracts. The cyanobacterial biomasses differed with respect to their dominant cyanobacterial species and microcystin contents. High acute toxicity was observed for 6 of the 8 crude biomass samples. Chronic exposure assays were performed using one complex biomass sample and its various subsamples/fractions. The complex biomass, the crude aqueous extract, and the microcystin-free SPE permeate all elicited similar and significant lethal effects, with LC50 values of around 35.6 mg biomass d.w L(-1) after 21 days. The cyanobacterial biomass samples also affected reproductive health, significantly increasing the time to the first brood (LOEC = 45 mg d.w L(-1) exposure) and inhibiting fecundity by 50% at 15 mg d.w L(-1). Conversely, the microcystin-containing C18-SPE eluate fraction had only weak effects in the chronic assay. These results indicate that cyanobacterial water blooms are highly toxic to zooplankton (both acutely and chronically) at environmentally relevant concentrations. However, the effects observed in the acute and chronic assays were independent of the samples' microcystin contents. Our results thus point out the importance of other cyanobacterial components such as lipopolysaccharides, various peptides and depsipeptides, polar alkaloid metabolites or other unidentified metabolites in the overall ecotoxicity of complex cyanobacterial blooms.
- MeSH
- bakteriální toxiny toxicita MeSH
- biomasa MeSH
- Daphnia účinky léků MeSH
- mikrocystiny toxicita MeSH
- rozmnožování účinky léků MeSH
- sinice chemie MeSH
- škodlivý vodní květ * MeSH
- testy akutní toxicity MeSH
- testy chronické toxicity MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
We analyzed antibacterial effects of several novel phthalocyanines against Escherichia coli and evaluated the suitability of flow cytometry for the detection of antibacterial effects of phthalocyanines in comparison with routinely used cultivation. After 3h of exposure under cool white light eight cationic phthalocyanines showed very high antibacterial activity in the concentration of 2.00 mg L(-1) and four of them were even efficient in the concentration of 0.20 mg L(-1). Antibacterial activity of neutral and anionic compounds was considerably lower or even negligible. No antibacterial effect was detected when bacteria were exposed without illumination. Binding affinity to bacterial cells was found to represent an important parameter influencing phthalocyanine antibacterial activity that can be modified by total charge of peripheral substituents and by the presence of suitable functional groups inside them. Agglomeration of cells observed in suspensions treated with a higher concentration of certain cationic phthalocyanines (the strongest binders to bacterial membrane) affected cytometric measurements of total cell counts, thus without appropriate pretreatment of the sample before analysis this parameter seems not to be fully valid in the evaluation of phthalocyanine antibacterial activity. Cytometric measurement of cell membrane integrity appears to be a suitable and even more sensitive parameter than cultivation.
- MeSH
- antibakteriální látky chemie farmakologie MeSH
- Escherichia coli účinky léků MeSH
- fotosenzibilizující látky chemie farmakologie MeSH
- indoly chemie farmakologie MeSH
- průtoková cytometrie MeSH
- singletový kyslík metabolismus MeSH
- světlo MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
The environmental occurrence and concentrations of cyanobacterial toxins (cyanotoxins) were investigated in the Czech Republic. Concentrations of microcystins (MCs), cylindrospermopsin (CYN) or saxitoxins (STXs) were determined immunochemically by ELISA assays in 30 water samples collected from the surface layers of 19 reservoirs during the summer season of 2010. MCs were detected in 18 reservoirs and 83 % of samples, with median and maximal concentration being 1.5 and 18.6 μg/L, respectively. The high frequency of MC occurrence coincided with prevalence of cyanobacterium Microcystis sp., which was detected in 87 % samples, followed by Dolichospermum (Anabaena) sp. observed in 33 % samples. CYN was detected by ELISA only in one sample at a concentration of 1.2 μg/L. STXs presence was indicated for the first time in Czech water reservoirs when the toxins were found at low concentrations (0.03-0.04 μg/L) in two samples (7 %) collected from two different reservoirs, where STXs co-occurred with MCs and eventually also with CYN. In both STX-positive samples, the phytoplankton community was dominated by Microcystis sp., but Dolichospermum sp. and/or Aphanizomenon sp. were also present as putative producers of STX and/or CYN. Cyanotoxins commonly occurred in Czech water reservoirs, and MCs frequently at concentrations possibly associated with human health risks. MCs were the most prevalent and abundant cyanotoxins, but also other cyanotoxins were detected, though sporadically. Further research and regulatory monitoring of cyanotoxins other than MCs is therefore required.
- MeSH
- Anabaena izolace a purifikace MeSH
- Aphanizomenon izolace a purifikace MeSH
- bakteriální toxiny analýza MeSH
- ELISA MeSH
- fytoplankton izolace a purifikace MeSH
- Microcystis izolace a purifikace MeSH
- mikrobiologie vody * MeSH
- mikrocystiny analýza MeSH
- monitorování životního prostředí metody statistika a číselné údaje MeSH
- mořské toxiny analýza MeSH
- neurotoxiny analýza MeSH
- saxitoxin analýza MeSH
- sinice izolace a purifikace MeSH
- sladká voda chemie mikrobiologie MeSH
- uracil analogy a deriváty analýza MeSH
- zásobování vodou analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
