Partial hydrolysis of poly(2-oxazoline)s yields poly[(2-oxazoline)-co-(ethylenimine)] copolymers that are of interest for a broad range of applications, from switchable surfaces, nanoparticles and hydrogels, to gene delivery and biosensors. In the present research, a fast and reproducible method is developed to obtain poly[(2-ethyl-2-oxazoline)-co-(ethylenimine)] (P(EtOx-co-EI)) copolymers via acid-catalyzed partial hydrolysis of poly(2-ethyl-2-oxazoline) (PEtOx). The hydrolysis kinetics were investigated by 1H-NMR spectroscopy and size exclusion chromatography using hexafluoroisopropanol as eluent. It was found that the hydrolysis was greatly accelerated by increasing the temperature from 100 °C up to near-critical water (275 °C) using microwave reactors; similar results were obtained in conventional pressure reactors at 180 °C. The optimal hydrolysis with regard to speed and control over the final copolymer structure was achieved at 180 °C, since the polymer was found to degrade and decompose above this temperature. In addition, control over the desired degree of hydrolysis of PEtOx was obtained by selecting the appropriate HCl concentration. To summarize, this work reports on defining optimal conditions to achieve tailored P(EtOx-co-EI) copolymers in a fast and reproducible way, utilizing high temperatures and controlled acidic conditions
Several studies suggest a link between shifts in gut microbiota and neurological disorders. Recently, we reported a high prevalence of Helicobacter suis (H. suis) in patients with Parkinson's disease. Here, we evaluated the effect of gastric H. suis infection on the brain in mice. One month of infection with H. suis resulted in increased brain inflammation, reflected in activation of microglia and cognitive decline. Additionally, we detected choroid plexus inflammation and disruption of the epithelial blood-cerebrospinal fluid (CSF) barrier upon H. suis infection, while the endothelial blood-brain barrier (BBB) remained functional. These changes were accompanied by leakage of the gastrointestinal barrier and low-grade systemic inflammation, suggesting that H. suis-evoked gastrointestinal permeability and subsequent peripheral inflammation induces changes in brain homeostasis via changes in blood-CSF barrier integrity. In conclusion, this study shows for the first time that H. suis infection induces inflammation in the brain associated with cognitive decline and that the choroid plexus is a novel player in the stomach-brain axis.
Helicobacter (H.) pylori is an important risk factor for gastric malignancies worldwide. Its outer membrane proteome takes an important role in colonization of the human gastric mucosa. However, in zoonotic non-H. pylori helicobacters (NHPHs) also associated with human gastric disease, the composition of the outer membrane (OM) proteome and its relative contribution to disease remain largely unknown. By means of a comprehensive survey of the diversity and distribution of predicted outer membrane proteins (OMPs) identified in all known gastric Helicobacter species with fully annotated genome sequences, we found genus- and species-specific families known or thought to be implicated in virulence. Hop adhesins, part of the Helicobacter-specific family 13 (Hop, Hor and Hom) were restricted to the gastric species H. pylori, H. cetorum and H. acinonychis. Hof proteins (family 33) were putative adhesins with predicted Occ- or MOMP-family like 18-stranded β-barrels. They were found to be widespread amongst all gastric Helicobacter species only sporadically detected in enterohepatic Helicobacter species. These latter are other members within the genus Helicobacter, although ecologically and genetically distinct. LpxR, a lipopolysaccharide remodeling factor, was also detected in all gastric Helicobacter species but lacking as well from the enterohepatic species H. cinaedi, H. equorum and H. hepaticus. In conclusion, our systemic survey of Helicobacter OMPs points to species and infection-site specific members that are interesting candidates for future virulence and colonization studies.
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