Self-propagating, molecular-level polymorphism in Alzheimer's beta-amyloid fibrils

Amyloid fibrils commonly exhibit multiple distinct morphologies in electron microscope and atomic force microscope images, often within a single image field. By using electron microscopy and solid-state nuclear magnetic resonance measurements on fibrils formed by the 40-residue beta-amyloid peptide of Alzheimer's disease (Abeta(1-40)), we show that different fibril morphologies have different underlying molecular structures, that the predominant structure can be controlled by subtle variations in fibril growth conditions, and that both morphology and molecular structure are self-propagating when fibrils grow from preformed seeds. Different Abeta(1-40) fibril morphologies also have significantly different toxicities in neuronal cell cultures. These results have implications for the mechanism of amyloid formation, the phenomenon of strains in prion diseases, the role of amyloid fibrils in amyloid diseases, and the development of amyloid-based nano-materials.     

Conservation of fish communities: Extending the ‘research life cycle’ by achieving practical effects

1. This article highlights the practical impact of our 2018 Aquatic Conservation: Marine and Freshwater Ecosystems publication, ‘Importance of peripheral basins: Implications for the conservation of fish assemblages’, which described fish communities in a Polish river.
2. Data on the fish assemblages of the Dniester River (Black Sea basin) are scarce; however, evidence indicates that the assemblages have declined. In our 2018 study, we hypothesized that the peripheral basin (the small basin on the edge) of the larger Upper Dniester River basin (the Strwi?? River) could maintain good ecological status and contained unique fish assemblages.
3. To examine the influence of historical factors and assess the role of peripheral basins on fish conservation, data from the Strwi?? basin were compared with the adjacent but unconnected Wiar basin (the Vistula basin; Baltic Sea basin). The Strwi?? River fish assemblages featured higher species richness and a greater number of native Ponto–Caspian species that function near the edge of their ranges.
4. This article focuses on four impacts of the 2018 publication: increasing awareness by various groups and organizations of the unique character of the surveyed river basin; highlighting important issues in assessing the ecological status of European rivers; driving the red‐listing of species and the development of stream fish conservation strategies; and identifying possible future impacts.
5. Our 2018 publication demonstrated the value of studying peripheral basins, which may affect conservation strategy development and encourage study of the importance of other peripheral basins and their role in aquatic resources conservation. Our article influenced the interpretation of fish‐based biotic indices and the conduct of monitoring work and its evaluation. It also strongly emphasized the native origin of the racer goby (Babka gymnotrachelus) in the Strwi?? River, which was important for subsequent works seeking to change the legal status of the species in Poland.

     

Identification and characterization of low molecular weight polyphenols in berry leaf extracts by HPLC-DAD and LC-ESI/MS

This paper reports the results of qualitative and quantitative analyses of low molecular weight phenolics from five berry leaf extract using HPLC-DAD and LC-ESI/MS. The identification of the black currant, raspberry, bilberry, honeysuckle, and strawberry leaf phytochemicals was based on the comparison of UV-vis absorption maxima (λ(max)) and mass spectral analysis. The peak identification in samples was also based on comparisons of the retention times (t(R)) of the isolated phytochemical standards. Knowledge of the precise phenolic profile of berry leaves may offer a scientific basis to put the underutilized berry leaves to good use as very cheap raw materials for polyphenol extract production. These studies indicated that these leaves can be used as a good and cheap source of bioactive constituents. These results suggest that berry leaves are a potential source of phenolics and have potential pro-healthy properties to contribute to human health.     

Polyphenolic compounds and antioxidant activity of new and old apple varieties

There is considerable evidence to show that a greater intake of apple contributes to improved health by reducing the risk of diseases, such as cardiovascular disease and some forms of cancer. Apple fruit is a major source of phenol compounds, because its consumption is widespread in many countries and it is available on the market for the whole year. The phenolic composition of 67 varieties of apple cultivars (new and old varieties) was examined for the concentration of some important phytochemicals and antioxidant activity. For the first time, we have looked at the correlation and compared polyphenolic coumpounds in Golden Delicious variety and new varieties grown from it. Up to 18 compounds, including catechin, procyanidin, hydroxycinnamates, flavonols, anthocyanins, and dihydrochalcones, were analyzed by high-performance liquid chromatography with diode array detection analysis of crude extracts and after thiolysis and LC-MS. The mean content of total polyphenols lay between 523.02 and 2723.96 mg/100 g dw and depending upon the apples variety. Flavanols (catechin and oligomeric procyanidins) are the major class of apple polyphenols, representing more than 80%, followed by hydroxycinnamic acids (1-31%), flavonols (2-10%), dihydrochalcones (0.5-5%), and in red apples, anthocyanins (1%). In this study, the best correlation was found for the total polyphenols and ABTS method, with a lower correlation for FRAP and DPPH methods ( r = 0.871, 0.839, and 0.804, respectively). The presented data clearly demonstrated that new varieties, i.e., Ozark Gold, Julyred, and Jester, of apple had the same or higher value of bioactive compounds in comparison to the old varieties, i.e., Golden Delicious, Idared, and Jonagold.     

Russian tortoises (Agrionemys horsfieldi) as a potential reservoir for Salmonella spp

A total of 80 Russian tortoises brought in Poland were examined for presence of Salmonella. Salmonella was detected in 15 out of all the animals tested (18.75%). Of the total of 56 strains, 30 (53.57%) belonged to Salmonella enterica subsp. enterica (I) and 26 to Salmonella enterica subsp. salamae (II). The predominant serotype within subspecies I was S. Newport, which is one of the most serotypes causing salmonellosis in humans and warm-blooded animals. In vitro determination of the susceptibility of Salmonella to the 10 medicinal preparations showed that all tested strains were sensitive to norfloxacin, sulfamethoxazole with trimethoprim, florfenicol, gentamicin, tetracycline and ampicillin, resistance was noted only to amoxicillin with clavulanic acid (12 strains), and intermediate sensitivity to colistin (7 strains), enrofloxacin (2 strains) and cephalexin (5 strains). These studies confirmed that Russian tortoises are a significant reservoir for Salmonella and may represent a potential source of infection for humans.     

Three species of Magnibursatus Naidenova, 1969 (Digenea: Derogenidae) from Atlantic and Black Sea marine teleosts

Three species of Magnibursatus Naidenova, 1969 are described from marine teleosts: M. skrjabini (Vlasenko, 1931), the type species of the genus, from the gobiid Zosterisessor ophiocephalus on the Bulgarian Black Sea coast; M. bartolii sp. n. from the sparid Boops boops off the Atlantic coast of Spain; and M. minutus sp. n. from the gobiid Neogobius eurycephalus on the Bulgarian Black Sea coast. M. bartolii differs from all other Magnibursatus species in its larger sinus-sac (length > 250 microm, width > 150 microm) and the more posterior location of testes. This species is also unusual in that it occurs in the branchial chamber and on the gills of its host. M. minutus is distinguished by the distinctly smaller dimensions of the body (length < 1000 microm, width < 200 microm), organs and eggs. These species are also distinguished from both M. caudofilamentosa (Reimer, 1971) and Tyrrhenia blennii Paggi et Orecchia, 1975. A key to the species of Magnibursatus is presented.     

Barley varieties in semi‐controlled and natural conditions—Response to water shortage and changing environment

The yield potential of 60 spring barley varieties was examined under controlled drought and natural conditions in the years 2011–2013. The studied varieties were genotyped with the 1536‐SNP barley oligonucleotide assay. In experiments with controlled drought conditions, the grain yield, 1,000‐grain weight, number of productive tillers and length of the main stem were measured. Physicochemical properties such as the specific surface area, water adsorption energy, fractal dimension and nanopore radius of the plant leaves were determined and correlated with yield‐forming traits. Field trials were conducted over 3 years at 14 locations, where along with the yield‐related traits, monthly rainfall and average temperature were monitored. Five varieties of high yield and five varieties relatively stable under both semi‐controlled and natural conditions were distinguished. The yield‐related traits observed in various locations were related to environmental variables relevant to water availability. The sum of the rainfall in April and May was negatively correlated with the 1,000‐grain weight and positively with the plant height. Positive relationships were found between plant height and temperatures in June and July. Five markers detected earlier as linked to the quantitative trait loci in the mapping populations were identified to have a coherent effect among varieties of various pedigree.     

General combining ability and heterosis regarding the phytochemical properties in strawberry (Fragaria × ananassa) hybrids

Strawberries are a common and important fruit in human diet because of their high content of essential nutrients and beneficial phytochemicals, which have relevant biological activity in human health. In this study, six cultivars and 15 selected F₁ hybrids between S₄ inbred lines and tester (cv. ‘Dukat’) were evaluated in a field trial over a period of two consecutive years. The amounts of total anthocyanin, phenolics and vitamin C in fruits and antiradical activity were analysed. General combining ability (GCA) and mid‐parent heterosis were also determined for those characteristics. Among all the genotypes tested, the inbred lines of ‘Senga Sengana’ 17 showed the highest breeding value based on GCA for all studied traits. Estimated heterosis varied among genotypes tested. The highest heterosis in terms of vitamin C occurred in the offspring of clone 1387 18‐15 × ‘Dukat’, but with regard to phenols and antiradical activity in hybrid ‘Teresa’ 18‐15 with cv. ‘Dukat’. This study revealed that the differentiation in chemical composition of strawberry fruits between genotypes is clearly dependent on individual genotype combinations and demonstrated the presence of heterosis in phytochemical contents in some specific genotypic combinations.     

Antioxidant activity of betanidin: electrochemical study in aqueous media

The antioxidative mechanism of action of betalains is of significant interest because these pigments are recently emerging as highly bio-active natural compounds with potential benefits to human health. Betanidin, the basic betacyanin, comprises the 5,6-dihydroxyl moiety, which results in its high antioxidant activity. Oxidation of betanidin by voltammetric techniques and chro matographic identification of the oxidation products with spectrophotometric and mass spectrometric detection (LC-DAD-MS/MS) were performed. Two main oxidation peaks for betanidin are observable at pH 3-5. These peaks become merged at higher pH, suggesting a different mechanism of oxidation at higher and lower pH values. The low oxidation potential of betanidin confirms its very strong reduction properties. The presence of two prominent oxidized products, 2-decarboxy-2,3-dehydrobetanidin and 2,17-bidecarboxy-2,3-dehydrobetanidin, indicates their generation through two reaction routes with two different quinonoid intermediates: dopachrome derivative and quinone methide. Both lead to the decarboxylative dehydrogenation of betanidin. Subsequent oxidation and rearrangement of the conjugated chromophoric system results in formation of 14,15-dehydrogenated derivatives.     

Similarity of fine specificity of IgA anti-gliadin antibodies between patients with celiac disease and humanized α1KI mice

Gliadins, and primarily α-gliadins containing several sequences such as aa 31-49, aa 56-88 (33-mer), aa 57-68, and aa 69-82, are critical in the induction of immune response or toxic reaction leading to the development of celiac disease (CLD). The role of IgA anti-gliadin antibodies (IgA AGA) is unknown. To this end, we prepared several humanized monoclonal IgA AGA using transgenic α1KI mice. Employing Pepscan with overlapping decapeptides of α-gliadin we observed a robust similarity between the specificity of humanized mouse monoclonal IgA AGA and IgA AGA from patients with florid CLD. The common immunodominant region included several sequential epitopes localized in the N-terminal part of α-gliadin (QFQGQQQPFPPQQPYPQPQPFP, aa 29-50, and QPFPSQQPYLQL, aa 47-58). Notably, IgA AGA produced by clones 8D12, 15B9, 9D12, and 18E2 had significant reactivity against sequences localized in the 33-mer, LQLQPFPQPQ (aa 56-65) and PQLPYPQPQPFL (aa 69-80). Humanized mouse monoclonal IgA AGA that have a known specificity are suitable as standard in ELISAs to detect serum IgA AGA of CLD patients and for studying the AGA pathogenic role in CLD, especially for analyzing the translocation of complex of specific IgA antibodies and individual gliadin peptides through enterocyte barrier.