Humans are exposed to phthalates released from plastics, cosmetics, or food on a daily basis. Phthalates have low acute liver toxicity, but their chronic exposures could induce molecular and cellular effects linked to adverse health outcomes, such as liver tumor promotion or chronic liver diseases. The alternation of gap junctional intercellular communication (GJIC) and MAPK-Erk1/2 pathways in liver progenitor or oval cells can disrupt liver tissue homeostatic mechanisms and affect the development and severity of these adverse outcomes. Our study with 20 different phthalates revealed their structurally dependent effects on liver GJIC and MAPK-Erk1/2 signaling in rat liver WB-F344 cell line with characteristics of liver oval cells. The phthalates with a medium-length side chain (3-6 C) were the most potent dysregulators of GJIC and activators of MAPK-Erk1/2. The effects occurred rapidly, suggesting the activation of non-genomic (non-transcriptional) mechanisms directly by the parental compounds. Short-chain phthalates (1-2 C) did not dysregulate GJIC even after longer exposures and did not activate MAPK-Erk1/2. Longer chain (≥7 C) phthalates, such as DEHP or DINP, moderately activated MAPK-Erk1/2, but inhibited GJIC only after prolonged exposures (>12 h), suggesting that GJIC dysregulation occurs via genomic mechanisms, or (bio)transformation. Overall, medium-chain phthalates rapidly affected the key tissue homeostatic mechanisms in the liver oval cell population via non-genomic pathways, which might contribute to the development of chronic liver toxicity and diseases.
- MeSH
- buněčné linie MeSH
- játra cytologie účinky léků metabolismus MeSH
- krysa rodu rattus MeSH
- kyseliny ftalové aplikace a dávkování chemie toxicita MeSH
- MAP kinasový signální systém účinky léků MeSH
- mezerový spoj účinky léků MeSH
- mezibuněčná komunikace účinky léků MeSH
- viabilita buněk účinky léků MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články 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
Phthalocyanines (Pcs, colored macromolecular compounds with the ability to generate singlet oxygen) represent a promising group of photosensitizers due to their intense absorption in the red and UV portion of the spectrum which leads to their excitation. In order to characterize possible toxic effects associated with eventual practical use and application of these chemicals, we employed an in vitro cell culture model to evaluate cytotoxic effects of 31 different phthalocyanines using neutral red uptake assay. An immortalized human keratinocyte cell line HaCaT was exposed to the tested chemicals for 2 or 24h, either with or without illumination in the last 60 min of the exposure period. After 2- or 24-h exposure without illumination, no cytotoxic effects or weak cytotoxic effects were induced by any Pc under the study and EC50 values could not be obtained within the tested concentration ranges (1.25-20 mg L(-1) or 0.625-10 mg L(-1)). On the other hand, exposure to phthalocyanines under illumination induced a significant cytotoxic effect. The most pronounced cytotoxicity was elicited by Pcs previously shown to have high positive charge densities at peripheral parts of substituent groups, which is most likely the factor responsible for the binding of Pc to negatively charged membranes on the cell surface and thus guaranteeing the tight connection necessary for the singlet oxygen attack on the cell surface.
Cyanobacteria pose a serious threat to water resources around the world. This is compounded by the fact that they are extremely resilient, having evolved numerous protective mechanisms to ensure their dominant position in their ecosystem. We show that treatment with nanoparticles of zerovalent iron (nZVI) is an effective and environmentally benign method for destroying and preventing the formation of cyanobacterial water blooms. The nanoparticles have multiple modes of action, including the removal of bioavailable phosphorus, the destruction of cyanobacterial cells, and the immobilization of microcystins, preventing their release into the water column. Ecotoxicological experiments showed that nZVI is a highly selective agent, having an EC(50) of 50 mg/L against cyanobacteria; this is 20-100 times lower than its EC(50) for algae, daphnids, water plants, and fishes. The primary product of nZVI treatment is nontoxic and highly aggregated Fe(OH)(3), which promotes flocculation and gradual settling of the decomposed cyanobacterial biomass.
- MeSH
- Araceae účinky léků růst a vývoj MeSH
- čištění vody metody MeSH
- Daphnia účinky léků fyziologie MeSH
- hořčice rodu Sinapis účinky léků růst a vývoj MeSH
- kořeny rostlin účinky léků růst a vývoj MeSH
- kovové nanočástice toxicita MeSH
- látky znečišťující vodu analýza MeSH
- listy rostlin účinky léků růst a vývoj MeSH
- Microcystis účinky léků růst a vývoj MeSH
- mikrobiologie vody MeSH
- mikrocystiny analýza MeSH
- Scenedesmus účinky léků růst a vývoj MeSH
- železo toxicita MeSH
- živorodka MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Phthalocyanines are prospective chemicals that have applications in industry, medicine and biology due especially to their architectural flexibility and production of reactive oxygen species. Although they are used in so many areas of human activities nowadays, there is still little knowledge of their ecotoxicity. Here we present the first observation of their toxic effects on representatives of the aquatic plants Lemna minor. The tested phthalocyanines possess a wide spectrum of phytotoxicity ranging from seldom (>50 mg L(-1)) to highly toxic 0.11 mg L(-1). Moreover, the potential of phthalocyanines to be used as selective cyanocides or herbicides is discussed as well.
Cyanobacteria proliferation is among the most threatening consequences of freshwater pollution. Health risks from human and other-organism exposure to cyanobacteria have led to an effort to find practical methods for cyanobacterial water-bloom reduction. Hence, methods and techniques have been developed in order to reduce the amount of phosphorus or to decrease the abundance of nuisance phytoplankton species directly in the water bodies (in-lake measures). Although these "acute" methods do not solve the problem of catchment area eutrophication, they are cheaper, easier to manage, and for some areas they are the only way to protect human and environmental health against massive cyanobacterial proliferation. This review summarizes the extent of knowledge and published data about the management using metals (Al, Fe, Cu, Ag, Ca), photosensitizers (hydrogen peroxide, phthalocyanines, TiO(2)), herbicides and chemicals derived from natural compounds as fast and efficient removal agents of cyanobacteria. This review concludes that some compounds, when non-persistent and ecotoxicologically acceptable may help to manage cyanobacterial blooms in an efficient way compared to previous methods (e.g. copper sulfate).
Phthalocyanines (Pcs) are promising photosensitizers for use in various branches of science and industry. In the presence of visible light and diatomic oxygen, phthalocyanines can react to produce singlet oxygen, a member of reactive oxygen species able to damage different molecules and tissues. The aim of this study was to investigate the ability of phthalocyanines to degrade natural toxins in the presence of visible light. As the representative of hardly degradable toxins, a group of cyanobacterial peptide toxins--microcystin-LR--was chosen for this study. According to our results, phthalocyanines are able to degrade 61.5% of microcystins within a 48-hour incubation (38% of microcystins was degraded after 24 h and 24% after 12 h of incubation). Although other oxidants like hydrogen peroxide or ozone are able to degrade microcystins within several hours, we assume that by optimizing the spectrum emitted by light source and by changing the absorption characteristics of Pcs, microcystins degradation by phthalocyanines could be more effective in the near future.
Phthalocyanines are promising photosensitizers for use in various branches of science including nanotechnology. In the presence of visible light and diatomic oxygen, phthalocyanines can react to produce singlet oxygen (1O2*), which has known inhibitory effects on cellular growth and metabolic activity, although other mechanisms may be involved. The present work focuses on the properties of phthalocyanines (atom charge densities, singlet oxygen production, inhibition effects at various irradiances) contributing to toxicity against the cyanobacteria, Synechococcus nidulans. Our results indicate that positive charge densities at peripheral parts of substituents exhibit greater inhibitory effects against S. nidulans than the amount of singlet oxygen produced, potentially by binding to negatively charged membranes on the cell surface. The weak effect of 1O2* was further demonstrated by a 10% increase in phthalocyanine toxicity (the maximal inhibition detected) when the irradiance increased 3-fold from 1200 to 4000 lux.
