Distinguishing regional and local sources of pollution by trace metals and magnetic particles in fluvial sediments of the Morava River, Czech Republic

Purpose

Regional contamination of southern Moravia (SE part of the Czech Republic) by trace metals and magnetic particles during the twentieth century was quantified in fluvial sediments of the Morava River. The influence of local pollution sources on regional contamination of the river sediments and the effect of sampling site heterogeneity were studied in sediment profiles with different lithologies.

Materials and methods

Hundreds of sediment samples were obtained from regulated channel banks and naturally inundated floodplains and proxy elemental analyses were carried out by energy dispersive X-ray fluorescence spectroscopy (ED XRF) and further calibrated by inductively coupled plasma mass spectrometry (ICP MS). Magnetic susceptibility was determined as a proxy for industrial contamination. The age model for the floodplain sediments was established from ¹³⁷Cs and ²¹⁰Pb dating. Trace metal contamination was assessed by establishing the lithological background values from floodplain profiles and calculating enrichment factors (EF) of trace metals (i.e. Pb, Zn, Cu) and magnetic susceptibility for the entire study area.

Results and discussion

Channel sediments are unsuitable for the reconstruction of historical regional contamination due to their lithological heterogeneity and the “chaotic” influence of local sources of contamination, as well as the possibility of geochemical mobility of pollutants. On the other hand, sediments from regulated river banks qualitatively reflected the actual, local contamination of the river system.

Conclusions

This approach allowed us to distinguish the influence of local sources of contamination by comparison with more spatially averaged contamination signals from distal floodplain profiles. The studied area is weakly contaminated (EF ～1–2), while individual sediment strata from regulated channel banks reflect local sources of contamination and contain up to several times higher concentrations of trace metals.     

Detection of the first lectin with antimicrobial activity present in serum of the Amazonian fish tambaqui Colossoma macropomum

Tambaqui Colossoma macropomum is the most important Amazonian native species in South American aquaculture. Innate immunity at least partially depends on the recognition of pathogen-associated molecular patterns by receptor-recognizing pathogens (PRRs). Some PRRs have been characterized in fishes, and several studies have focused on the role of lectins in the immune system of various fishes. Lectins are proteins that specifically recognize carbohydrates and which have important biological functions. Tambaqui serum lectin (ComaSeL), which was identified on the basis of its hemagglutinating activity, was pre-purified, biochemically characterized, and used in assays of antibacterial activity against pathogenic bacteria in freshwater fishes. A study of the seasonality of this lectin was performed. Comasel activity was stable at a pH between 4.0 and 9.0 and lost 100?% of its activity at 70?°C. It recognized the carbohydrates d-galactose, 1-O-methyl-d-galactopyranoside, and d-fucose, showing antibacterial activity for Gram-negative bacteria. Its activity showed significant differences between the summer and winter (p?<?0.05, Tukey test), thereby corroborating observations that tambaqui becomes more susceptible to mortality from diseases caused by bacteria and fungi during the winter. With this information, new tools may be developed for gaining a better understanding of the role of these proteins in the immune system of the tambaqui, ultimately resulting in the improved management of this fish by pisciculturists.     

Cadmium-induced production of phytochelatins and speciation of intracellular cadmium in organs of Linum usitatissimum seedlings

The capacity of most flax (Linum usitatissimum L.) varieties and cultivars to accumulate cadmium (Cd), underlined by their Cd-tolerant phenotype, brought an interest in their use in phytoextraction of soil Cd to aboveground biomass. The aim of this study was to gain an insight into the mechanism of intracellular detoxification of Cd, by exploring the response of flax seedlings, cultivar AGT 952, to 12 days growth at 50-500 μM Cd. The majority of accumulated Cd (67-74%) was retained in roots, which showed reduced elongation (by 50% at 100 μM Cd) and 3.5 (at 50 μM Cd) to 9.6 (at 500 μM Cd) times higher concentration of Cd than in shoots. Labeling of roots with Leadmium fluorescent marker visualized intracellular localization of Cd. High-performance liquid chromatography of extracts from Cd-treated seedlings revealed induced synthesis of phytochelatins, small intracellular peptides binding Cd through cysteine of their repeating (γ-Glu-Cys)_n motives (PCn). Regardless the treatment, PC3 was dominant in all organs and PC2 was restricted to cotyledons. Larger PC4 and PC5 accumulated only in roots grown at 500 μM Cd. Size exclusion chromatography of the organ extracts from seedlings exposed to 100 μM revealed the presence of 2-kDa complexes equated to low-molecular weight (LMW) Cd-PC complexes. In roots, the majority of Cd was stored in ≥9-kDa complex corresponding in apparent molecular mass to stable high-molecular weight (HMW) CdS-PC complexes of yeasts and plants. Data demonstrate that, like in most other plants, the response of flax to Cd involved phytochelatins and suggested that the deposition of Cd in HMW complex should be considered the intrinsic feature reducing translocation of Cd to shoots.     

New defensins from hard and soft ticks: Similarities,differences, and phylogenetic analyses

Despite the importance of ticks as vectors of disease very little is known about their immune system. Antimicrobial peptides, including defensins (phylogenetically ancient antibacterial peptides) are major components of innate immunity in ticks that have been shown to provide protection against gram-negative and gram-positive bacteria, fungi, viruses and protozoan parasites. With the aim of studying the evolution of the genes involved in tick defense, we identified the preprodefensin genes from four Ornithodoros tick species (O. papillipes: isoforms A, B, and D; O. tartakovskyi and O. puertoricensis: isoforms A and B; O. rostratus: isoform A) and from two Dermacentor tick species (D. reticulatus and D. marginatus: one isoform) not previously described. Phylogenetic analyses revealed that Ornithodoros defensin isoforms (A, B, C, and D) form 4 separate clades, while hard tick defensins are divided into several branches based on particular tick species.     

SIRT1-dependent modulation of methylation and acetylation of histone H3 on lysine 9 (H3K9) in the zygotic pronuclei improves porcine embryo development

Background: The histone code is an established epigenetic regulator of early embryonic development in mammals.The lysine residue K9 of histone H3(H3 K9) is a prime target of SIRT1, a member of NAD+-dependent histone deacetylase family of enzymes targeting both histone and non-histone substrates. At present, little is known about SIRT1-modulation of H3 K9 in zygotic pronuclei and its association with the success of preimplantation embryo development. Therefore, we evaluated the effect of SIRT1 activity on H3 K9 methylation and acetylation in porcine zygotes and the significance of H3 K9 modifications for early embryonic development.Results: Our results show that SIRT1 activators resveratrol and BML-278 increased H3 K9 methylation and suppressed H3 K9 acetylation in both the paternal and maternal pronucleus. Inversely, SIRT1 inhibitors nicotinamide and sirtinol suppressed methylation and increased acetylation of pronuclear H3 K9. Evaluation of early embryonic development confirmed positive effect of selective SIRT1 activation on blastocyst formation rate(5.2 ± 2.9% versus 32.9 ± 8.1% in vehicle control and BML-278 group, respectively; P ≤ 0.05). Stimulation of SIRT1 activity coincided with fluorometric signal intensity of ooplasmic ubiquitin ligase MDM2, a known substrate of SIRT1 and known limiting factor of epigenome remodeling.Conclusions: We conclude that SIRT1 modulates zygotic histone code, obviously through direct deacetylation and via non-histone targets resulting in increased H3 K9 me3. These changes in zygotes lead to more successful pre-implantation embryonic development and, indeed, the specific SIRT1 activation due to BML-278 is beneficial for in vitro embryo production and blastocyst achievement.     

Polyoxygenated Steroids from the Octocoral Leptogorgia punicea and in Vitro Evaluation of Their Cytotoxic Activity

Five new polyoxygenated marine steroids—punicinols A–E (1–5)—were isolated from the gorgonian Leptogorgia punicea and characterized by spectroscopic methods (IR, MS, ¹H, ¹³C and 2-D NMR). The five compounds induced in vitro cytotoxic effects against lung cancer A549 cells, while punicinols A and B were the most active, with IC₅₀ values of 9.7 μM and 9.6 μM, respectively. The synergistic effects of these compounds with paclitaxel, as well as their effects on cell cycle distribution and their performance in the clonogenic assay, were also evaluated. Both compounds demonstrated significant synergistic effects with paclitaxel.     

Proposed Methodology for Quality Preselection of Rice Populations

The evaluation of culinary and sensory characteristics of a particular cultivar is an important trait for rice grain quality because it guides decisions for breeding programs and allows the prediction of rice market acceptance. The aim of this study was to apply direct and indirect tests for the characterization of the grain quality in a segregating rice population under different treatments (2 × 2). A methodology was proposed from the data based on mathematical equations to aid rice breeding programs in the preselection of promising genotypes. Grain samples were evaluated for apparent amylose content, gelatinization temperature, and viscoamylographic profile. In addition, the samples were subjected to a cooking test. The evaluated parameters were weighted and grouped into two linear equations, yielding scores that were subjected to the selection criteria. Using this methodology, families of the studied population were preselected, which reduced the number of samples for final selection by at least 76%. The physical‐chemical analysis did not indicate a direct positive correlation to accurately infer the culinary and sensorial quality of the rice for human consumption, but this analysis was shown to be useful in the preselection of lineages through the proposed strategy.     

Combining Sewage Sludge and Clam Shell Waste to Prepare Adsorbents for Efficient Phosphorous Removal

Effluents containing phosphorous as phosphate ions are frequently discharged in freshwater resources contributing to the eutrophication and directly interfering in the biological equilibrium. Clam shell residues and sewage sludge were combined for preparing efficient adsorbents for phosphate removal from aqueous medium. The adsorbents were characterized before and after adsorption testing, and the adsorption equilibrium and kinetics were investigated. Phosphate removal of 89?±?1% was attained for samples prepared with 0.1?< X <?1.0, where X corresponds to sewage sludge/clam shell mass ratio. The analyses of the experimental errors indicated that the phosphorous removal followed the Elovich kinetic model, which describes adsorption in very heterogeneous surfaces. On the other hand, the best modelling was achieved using the Koble–Corrigan isotherm model, which incorporate different aspects of both Langmuir and Freundlich isotherms to represent the equilibrium data. The observed adsorption capacity (21.4 mgP g^?1) are comparable or greater to that observed for other adsorbents described in the literature.