Nontuberculous mycobacteria (NTM) are ubiquitous organisms of a wide variety of environmental reservoirs, including natural and municipal water, soil, aerosols, protozoans, animals and humans. Several of these species are potential pathogens which affect human health. The aim of this study was to determine the occurrence of NTM in the water environment. Samples were taken from 13 water-related facilities including fish ponds, storage ponds, drinking water reservoirs and an experimental recirculation system. Altogether, 396 samples of water, sediment and aquatic plants were collected and analysed. All samples were examined using conventional culture methods. Suspected microbial isolates were subjected to polymerase chain reaction analysis and identified using partial sequence analysis of the 16S rDNA gene. The culture revealed 94/396 samples (23.7%) that contained mycobacteria. Among known NTM we identified potentially pathogenic mycobacteria isolated from the fresh water environment for the first time: Mycobacterium asiaticum, M. chimaera, M. interjectum, M. kumamotonense, M. lentiflavum, M. montefiorense, M. nebraskense, M. paraffinicum and M. simiae. Epidemiologic studies suggest that the natural water environment is the principal source of human exposure. Our results indicate that besides the well-known potentially pathogenic mycobacteria it is important to observe occurrence, proliferation and persistence of newly discovered mycobacterial species.

• MeSH
• mikrobiota MeSH
• Mycobacterium genetika   izolace a purifikace   MeSH
• pitná voda mikrobiologie   MeSH
• polymerázová řetězová reakce MeSH
• RNA ribozomální 16S genetika   metabolismus   MeSH
• roční období MeSH
• sekvenční analýza DNA MeSH
• sladká voda mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• pitná voda MeSH
• RNA ribozomální 16S MeSH

Fruits of Schisandra chinensis, an East Asian liana plant, are currently more and more used to produce nutrient supplements that positively affect human health due to the content of various secondary metabolites. On the other hand, these substances because of their bioactivity can cause possible allelopathic or toxic effects concerning other organisms (algae, plants, animals). But the ecotoxicological properties of S. chinensis outside its area of origin have yet to be sufficiently verified. Two crustaceans, Daphnia magna and Thamnocephalus platyurus, were selected as model aquatic organisms to test the potential impact of S. chinensis active compounds on the aquatic environment. Crude water extract from S. chinensis fruits, simulating the natural leakage of active substances in water, was tested in treatments from 0.0045 to 45 mg/L (according to the content of schisandrin as the dominating lignan). Effective concentration (EC50) causing 50% lethal effect for D. magna was established to 0.0448 mg/L after 24 h and 0.0152 mg/L after 48 h. EC50 for T. platyurus reached 0.4572 mg/L after 24 h, i.e. more than ten times higher than for D. magna. This study showed that the potential environmentally relevant concentrations of S. chinensis bioactive compounds could represent a severe risk to aquatic ecosystems.

• Klíčová slova
• Acute toxicity, Adaptogen, Lignan, Schisandrin, Zooplankton,
• MeSH
• Anostraca MeSH
• chemické látky znečišťující vodu * toxicita   MeSH
• Daphnia MeSH
• ekosystém MeSH
• lidé MeSH
• Schisandra * MeSH
• testy akutní toxicity MeSH
• voda MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chemické látky znečišťující vodu * MeSH
• voda MeSH

Plastic pollution poses a serious risk to the oceans, freshwater ecosystems, and land-based agricultural production. Most plastic waste enters rivers and then reaches the oceans, where its fragmentation process begins and the forming of microplastics (MPs) and nanoplastics (NPs). These particles increase their toxicity by the exposition to external factors and binding environmental pollutants, including toxins, heavy metals, persistent organic pollutants (POPs), halogenated hydrocarbons (HHCs), and other chemicals, which further and cumulatively increase the toxicity of these particles. A major disadvantage of many MNPs in vitro studies is that they do not use environmentally relevant microorganisms, which play a vital role in geobiochemical cycles. In addition, factors such as the polymer type, shapes, and sizes of the MPs and NPs, their exposure times and concentrations must be taken into account in in vitro experiments. Last but not least, it is important to ask whether to use aged particles with bound pollutants. All these factors affect the predicted effects of these particles on living systems, which may not be realistic if they are insufficiently considered. In this article, we summarize the latest findings on MNPs in the environment and propose some recommendations for future in vitro experiments on bacteria, cyanobacteria, and microalgae in water ecosystems.

• Klíčová slova
• Microplastic, Nanoplastic, Ocean pollution, Toxicity,
• MeSH
• chemické látky znečišťující vodu * toxicita   analýza   MeSH
• ekosystém MeSH
• mikroplasty * toxicita   MeSH
• plastické hmoty toxicita   MeSH
• voda MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• chemické látky znečišťující vodu * MeSH
• mikroplasty * MeSH
• plastické hmoty MeSH
• voda MeSH

The particle size distribution of particulate matter (PM) and concentrations of water-soluble ions were observed in airborne aerosol in the City of Ostrava (the Czech Republic, Moravian-Silesian Region) during winter 2016. The Ostrava area ranks among the most polluted areas not only within the Czech Republic but also in Europe due to the high concentration of industry, especially metallurgy, in this area. The selected water-soluble ions: were studied in different grain size classes of particulate matter separated into 7 fractions (from 0.0175 to 9.93 μm) collected by an electrical low pressure impactor ELPI+. Assessment of the influence of meteorological parameters and various sources of contamination (transportation, industry, and residential burning) in heavily environmentally-burdened urban areas was attempted. This study proved that (K)+ is related to metallurgical processes and its role as an indicator of biomass combustion is negligible. The highest concentrations of all water-soluble ions were determined in particles below 0.952 μm that is generally related to combustion processes. At increased air temperature (in the interval from 0 °C to 10 °C), concentrations of both dust particles and the sum of water-soluble ions are decreasing.

• Klíčová slova
• Cascade impactor ELPI(+), Enrichment factor, Meteorological parameters, Ostrava, Particulate matter, Water-soluble inorganic ions,
• MeSH
• aerosoly MeSH
• ionty MeSH
• látky znečišťující vzduch * MeSH
• monitorování životního prostředí MeSH
• pevné částice MeSH
• prach * MeSH
• roční období MeSH
• velikost částic MeSH
• velkoměsta MeSH
• voda MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH
• Evropa MeSH
• velkoměsta MeSH
• Názvy látek
• aerosoly MeSH
• ionty MeSH
• látky znečišťující vzduch * MeSH
• pevné částice MeSH
• prach * MeSH
• voda MeSH

Ab initio and molecular simulation methods were used in calculations of the neutral individual betulin molecule, and molecular simulations were used to optimize the betulin molecule immersed in various amounts of water. Individual betulin was optimized in different force fields to find the one exhibiting best agreement with ab initio calculations obtained in the Gaussian03 program. Dihedral torsions of active groups of betulin were determined for both procedures, and related calculated structures were compared successfully. The selected force field was used for subsequent optimization of betulin in a water environment, and a conformational search was performed using quench molecular dynamics. The total energies of betulin and its interactions in water bulk were calculated, and the influence of water on betulin structure was investigated.

• MeSH
• molekulární konformace MeSH
• molekulární modely MeSH
• počítačová simulace MeSH
• simulace molekulární dynamiky * MeSH
• triterpeny chemická syntéza   chemie   MeSH
• voda chemie   MeSH
• vodíková vazba MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• betulin MeSH Prohlížeč
• triterpeny MeSH
• voda MeSH

The paper deals with an analysis of the amount of 16 polycyclic aromatic hydrocarbons (PAHs (Polycyclic aromatic hydrocarbons-16 defined by US EPA.)) released from reclaimed asphalt mixtures used in base layers of road surfaces and in binder layers in road construction using cold in-place recycling. For the ten samples tested, the sum of 16 PAHs was determined directly for the crushed asphalt mixture and for its 24-h leachate. The crushed asphalt samples were used to make cylindrical asphalt specimens of the cold recycling mixture. The asphalt specimens were prepared to simulate as realistically as possible the use of the mixtures in road reconstructions implementing the cold in-place recycling technology, which should ensure the passivation of PAHs. The asphalt specimens were subjected to a dynamic leaching test under laboratory conditions with regular replacement of the leaching liquid. The results showed that the concentration of PAHs released into the water environment from the test specimens (passivated material) was approximately 40-50% lower than the amount of PAHs released from the asphalt mixtures in the 24-h leaching test. When compared to the input PAH concentrations in the asphalt mixtures (36-1323 mg.kg-1), on average, only 0.15% of PAHs is released from the passivated material. Dynamic leaching test has shown that the wrapping of the original asphalt mixture with a new binder and its subsequent compaction leads to the preservation of PAHs in the original material at such a level that their total concentrations are reduced by two orders of magnitude.

• Klíčová slova
• 16 EPA PAHs, Asphalt specimens, Leaching, PAH passivation, Reclaimed asphalt mixture, Water contamination,
• MeSH
• chemické látky znečišťující vodu * analýza   MeSH
• polycyklické aromatické uhlovodíky * analýza   MeSH
• recyklace * MeSH
• uhlovodíky * analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• asphalt MeSH Prohlížeč
• chemické látky znečišťující vodu * MeSH
• polycyklické aromatické uhlovodíky * MeSH
• uhlovodíky * MeSH

Our Moon periodically moves through the magnetic tail of the Earth that contains terrestrial ions of hydrogen and oxygen. A possible density contrast might have been discovered that could be consistent with the presence of water phase of potential terrestrial origin. Using novel gravity aspects (descriptors) derived from harmonic potential coefficients of gravity field of the Moon, we discovered gravity strike angle anomalies that point to water phase locations in the polar regions of the Moon. Our analysis suggests that impact cratering processes were responsible for specific pore space network that were subsequently filled with the water phase filling volumes of permafrost in the lunar subsurface. In this work, we suggest the accumulation of up to ~ 3000 km3 of terrestrial water phase (Earth's atmospheric escape) now filling the pore spaced regolith, portion of which is distributed along impact zones of the polar regions of the Moon. These unique locations serve as potential resource utilization sites for future landing exploration and habitats (e.g., NASA Artemis Plan objectives).

• MeSH
• gravitace MeSH
• Měsíc * MeSH
• mimozemské prostředí MeSH
• voda * MeSH
• Země (planeta) MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• voda * MeSH

Plastic particles smaller than 5 mm, i.e., microplastics, have been detected in a number of environments. The number of studies on microplastics in marine environments, fresh water, wastewater, the atmosphere, and the human body are increasing along with a rise in the amounts of plastic materials introduced into the environment every year, all contributing to a range of health and environmental issues. Although the use of primary microplastics has been gradually reduced by recent legislation in many countries, new knowledge and data on these problems are needed to understand the overall lifecycle of secondary microplastics in particular. The aim of this review is to provide unified information on the pathways of microplastics into the environment, their degradation, and related legislation, with a special focus on the methods of their sampling, determination, and instrumental analysis. To deal with the health and environmental issues associated with the abundance of microplastics in the environment, researchers should focus on agreeing on a uniform methodology to determine the gravity of the problem through obtaining comparable data, thus leading to new and stricter legislation enforcing more sustainable plastic production and recycling, and hopefully contributing to reversing the trend of high amounts of microplastics worldwide.

• Klíčová slova
• aquatic environment, determination, legislation, microplastics, water,
• MeSH
• chemické látky znečišťující vodu * analýza   MeSH
• lidé MeSH
• mikroplasty * MeSH
• monitorování životního prostředí MeSH
• plastické hmoty MeSH
• sladká voda MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• chemické látky znečišťující vodu * MeSH
• mikroplasty * MeSH
• plastické hmoty MeSH

Water deficit is a major limiting condition for adaptation of maize in tropical environments. The aims of the current observations were to evaluate the kernel water relations for determining kernel developmental progress, rate, and duration of kernel filling, stem reserve mobilization in maize. In addition, canopy temperature, cell membrane stability, and anatomical adaptation under prolonged periods of pre- and post-anthesis water deficit in different hybrids was quantified to support observations related to kernel filling dynamics. In this context, two field experiments in two consecutive years were conducted with five levels of water regimes: control (D1), and four water deficit treatments [V10 to V13 (D2); V13 to V17 (D3); V17 to blister stage (D4); blisters to physiological maturity (D5)], on three maize hybrids (Pioneer 30B80, NK 40, and Suwan 4452) in Expt. 1. Expt. 2 had four water regimes: control (D1), three water deficit treatments [V10 to anthesis (D2); anthesis to milk stage (D3); milk to physiological maturity (D4)], and two maize hybrids (NK 40 and Suwan 4452). Water deficit imposed at different stages significantly reduced maximum kernel water content (MKWC), kernel filling duration (KFD), final kernel weight (FKW), and kernel weight ear-1 while it increased kernel water loss rate (KWLR), kernel filling rate (KFR), and stem weight depletion (SWD) across maize hybrids in both experiments. The lowest MKWC under water deficit was at D3 in both experiments, indicating that lower KFR results in lowest FKW in maize. Findings indicate that the MKWC (R 2 = 0.85 and 0.41) and KFR (R 2 = 0.62 and 0.37) were positively related to FKW in Expt. 1 and 2, respectively. The KFD was reduced by 5, 7, 7, and 11 days under water deficit at D3, D4 in Expt. 2 and D4, D5 in Expt. 1 as compared to control, respectively. Water deficit at D5 in Expt. 1 and D4 in Expt. 2 increased KWLR, KFR, and SWD. In Expt. 2, lower canopy temperature and electrical conductivity indicated cell membrane stability across water regimes in NK 40. Hybrid NK 40 under water deficit had significantly higher cellular adaptation by increasing the number of xylem vessel while reducing vessel diameter in leaf mid-rib and attached leaf blade. These physiological adjustments improved efficient transport of water from root to the shoot, which in addition to higher kernel water content, MKWC, KFD, KFR, and stem reserve mobilization capacity, rendered NK 40 to be better adapted to water-deficit conditions under tropical environments.

• Klíčová slova
• kernel filling traits, kernel water relations, maize, stem reserve mobilization, water deficit,
• Publikační typ
• časopisecké články MeSH

Some freshwater phytoplankton species have been suggested to produce estrogenic compounds in concentrations which could cause adverse effects to aquatic biota, while other studies showed no estrogenic effects after exposure to phytoplankton extracts or pointed out possible sources of the overestimation of the estrogenic activity. This study aimed to clarify these research inconsistencies by investigating estrogenicity of biomass extracts from both environmental freshwater blooms and laboratory cyanobacterial and algae cultures by in vitro reporter bioassay. Biomasses of 8 cyanobacterial and 3 algal species from 7 taxonomic orders were extracted and tested. Next to this, samples of environmental water blooms collected from 8 independent water bodies dominated by phytoplankton species previously assessed as laboratory cultures were tested. The results showed undetectable or low estrogenicity of both freshwater blooms and laboratory cultures with E2 equivalent concentration (EEQ) in a range from LOQ up to 4.5 ng EEQ/g of dry mass. Moreover, the co-exposure of biomass extracts with environmentally relevant concentration of model estrogen (steroid hormone 17β-estradiol; E2), commonly occurring in surface waters, showed simple additive interaction. However, some of the biomass extracts elicited partially anti-estrogenic effects in co-exposure with higher E2 concentration. In conclusion, our study documents undetectable or relatively low estrogenic potential of biomass extracts from both environmental freshwater blooms and studied laboratory cultured cyanobacterial and algae species. Nevertheless, in case of very high-density water blooms, even this low estrogenicity (detected for two cyanobacterial species) could lead to EEQ content in biomass reaching effect-based trigger values indicating potential risk, if recalculated per water volume at field sites. However, these levels would not occur in water under realistic environmental scenarios and the potential estrogenic effects would be most probably minor compared to other toxic effects caused by massive freshwater blooms of such high densities.

• Klíčová slova
• Anti-Estrogenicity, Aquatic ecosystem, Cyanobacteria, Estrogen, Freshwater bloom, Phytoplankton,
• MeSH
• estradiol toxicita   MeSH
• estrogeny * toxicita   analýza   MeSH
• estron MeSH
• fytoplankton MeSH
• sinice * MeSH
• voda MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• estradiol MeSH
• estrogeny * MeSH
• estron MeSH
• voda MeSH