The Synthetic Antimicrobial Peptide 19-2.5 Interacts with Heparanase and Heparan Sulfate in Murine and Human Sepsis

Heparanase is an endo-β-glucuronidase that cleaves heparan sulfate side chains from their proteoglycans. Thereby, heparanase liberates highly potent circulating heparan sulfate-fragments (HS-fragments) and triggers the fatal and excessive inflammatory response in sepsis. As a potential anti-inflammatory agent for sepsis therapy, peptide 19–2.5 belongs to the class of synthetic anti-lipopolysaccharide peptides; however, its activity is not restricted to Gram-negative bacterial infection. We hypothesized that peptide 19–2.5 interacts with heparanase and/or HS, thereby reducing the levels of circulating HS-fragments in murine and human sepsis. Our data indicate that the treatment of septic mice with peptide 19–2.5 compared to untreated control animals lowers levels of plasma heparanase and circulating HS-fragments and reduces heparanase activity. Additionally, mRNA levels of heparanase in heart, liver, lung, kidney and spleen are downregulated in septic mice treated with peptide 19–2.5 compared to untreated control animals. In humans, plasma heparanase level and activity are elevated in septic shock. The ex vivo addition of peptide 19–2.5 to plasma of septic shock patients decreases heparanase activity but not heparanase level. Isothermal titration calorimetry revealed a strong exothermic reaction between peptide 19–2.5 and heparanase and HS-fragments. However, a saturation character has been identified only in the peptide 19–2.5 and HS interaction. In conclusion, the findings of our current study indicate that peptide 19–2.5 interacts with heparanase, which is elevated in murine and human sepsis and consecutively attenuates the generation of circulating HS-fragments in systemic inflammation. Thus, peptide 19–2.5 seems to be a potential anti-inflammatory agent in sepsis.     

Comparative Hazard Identification by a Single Dose Lung Exposure of Zinc Oxide and Silver Nanomaterials in Mice

Comparative hazard identification of nanomaterials (NMs) can aid in the prioritisation for further toxicity testing. Here, we assessed the acute lung, systemic and liver responses in C57BL/6N mice for three NMs to provide a hazard ranking. A silver (Ag), non-functionalised zinc oxide (ZnO) and a triethoxycaprylylsilane functionalised ZnO NM suspended in water with 2% mouse serum were examined 24 hours following a single intratracheal instillation (I.T.). An acute pulmonary inflammation was noted (marked by a polymorphonuclear neutrophil influx) with cell damage (LDH and total protein) in broncho-alveolar lavage fluid (BALF) after administration of both non-functionalised and functionalised ZnO. The latter also induced systemic inflammation measured as an increase in blood neutrophils and a decrease in blood lymphocytes. Exposure to Ag NM was not accompanied by pulmonary inflammation or cytotoxicity, or by systemic inflammation. A decrease in glutathione levels was demonstrated in the liver following exposure to high doses of all three nanomaterials irrespective of any noticeable inflammatory or cytotoxic effects in the lung. By applying benchmark dose (BMD) modeling statistics to compare potencies of the NMs, we rank functionalised ZnO ranked the highest based on the largest number of affected endpoints, as well as the strongest responses observed after 24 hours. The non-functionalised ZnO NM gave an almost similar response, whereas Ag NM did not cause an acute response at similar doses.     

Characteristics of digestive enzymes of calanoid copepod species from different latitudes in relation to temperature, pH and food

In calanoid copepods it is poorly understood how enzymatic activities and patterns are affected by abiotic and biotic factors. Such knowledge, however, is crucial to assess metabolic functioning and performance of organisms in different habitats. Therefore, our study focuses on digestive enzyme activities in relation to temperature, pH and food in the Arctic species Calanus glacialis and in Centropages hamatus and Temora longicornis from the North Sea. Enzyme activities were measured over a range from 0 to 70 °C (lipases/esterases, proteinases) and pH 5 to 9 (proteinases). In all species, relative proteinases activity peaked at 40/50 °C and pH 6; relative lipases/esterases activity peaked at 30 °C. Between 0 and 20 °C, lipase activity of C. glacialis was higher (40-70% of maximum) than that of the boreal copepods (25-64%), which suggests thermal adaptation of the lipid metabolism in the polar species. Incubating C. glacialis with the diatom Thalassiosira weissflogii showed (i) that enzyme activities increased especially in the alkaline range and (ii) that enzyme patterns, revealed by gel electrophoresis, differed from that of starving individuals, indicating that feeding induced enzyme expression. Such studies, linking abiotic and biotic conditions to enzyme functioning, can help elucidating the capacity of copepods to respond to environmental changes.     

Inhibition and disaggregation of α-synuclein oligomers by natural polyphenolic compounds

Aggregation of alpha-synuclein (αS) into oligomers is critically involved in the pathogenesis of Parkinson's disease (PD). Using confocal single-molecule fluorescence spectroscopy, we have studied the effects of 14 naturally-occurring polyphenolic compounds and black tea extract on αS oligomer formation. We found that a selected group of polyphenols exhibited potent dose-dependent inhibitory activity on αS aggregation. Moreover, they were also capable of robustly disaggregating pre-formed αS oligomers. Based upon structure-activity analysis, we propose that the key molecular scaffold most effective in inhibiting and destabilizing self-assembly by αS requires: (i) aromatic elements for binding to the αS monomer/oligomer and (ii) vicinal hydroxyl groups present on a single phenyl ring. These findings may guide the design of novel therapeutic drugs in PD.     

Fractionation of wheat and barley straw to access high-molecular-mass hemicelluloses prior to ethanol production

The cost efficiency of the biorefining process can be improved by extracting high-molecular-mass hemicelluloses from lignocellulosic biomass prior to ethanol production. These hemicelluloses can be used in several high-value-added applications and are likely to be important raw materials in the future. In this study, steam pretreatment in an alkaline environment was used to pretreat the lignocellulosic biomass for ethanol production and, at the same time, extract arabinoxylan with a high-molecular-mass. It was shown that 30% of the arabinoxylan in barley straw could be extracted with high-molecular-mass, without dissolving the cellulose. The cellulose in the solid fraction could then be hydrolysed with cellulase enzymes giving a cellulose conversion of about 80–90% after 72 h. For wheat straw, more than 40% of the arabinoxylan could be extracted with high-molecular-mass and the cellulose conversion of the solid residue after 72 h was about 70–85%. The high cellulose conversion of the pretreated wheat and barley straw shows that they can be used for ethanol production without further treatment. It is therefore concluded that it is possible to extract high-molecular-mass arabinoxylan simultaneously with the pretreatment of biomass for ethanol production in a single steam pretreatment step.     

MC1R Genotype and Plumage Colouration in the Zebra Finch (Taeniopygia guttata): Population Structure Generates Artefactual Associations

Polymorphisms at the melanocortin-1 receptor (MC1R) gene have been linked to coloration in many vertebrate species. However, the potentially confounding influence of population structure has rarely been controlled for. We explored the role of the MC1R in a model avian system by sequencing the coding region in 162 zebra finches comprising 79 wild type and 83 white individuals from five stocks. Allelic counts differed significantly between the two plumage morphs at multiple segregating sites, but these were mostly synonymous. To provide a control, the birds were genotyped at eight microsatellites and subjected to Bayesian cluster analysis, revealing two distinct groups. We therefore crossed wild type with white individuals and backcrossed the F1s with white birds. No significant associations were detected in the resulting offspring, suggesting that our original findings were a byproduct of genome-wide divergence. Our results are consistent with a previous study that found no association between MC1R polymorphism and plumage coloration in leaf warblers. They also contribute towards a growing body of evidence suggesting that care should be taken to quantify, and where necessary control for, population structure in association studies.