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Abstract: In this work, choline chloride and betaine hydrochloride were condensed into a - to our knowledge - unreported choline betainate (N,N,N-trimethyl-2-oxo-2-(2-(trimethylammonio)ethoxy)ethanaminium chloride) using 1,1′-carbonyldiimidazole (CDI) activation of betaine hydrochloride in dimethylsulfoxide. The product and reaction intermediates were isolated, purified by preparative HPLC and analyzed in detail by infrared and nuclear magnetic resonance spectroscopy. The final product has a high cytotoxicity for L929 mouse fibroblasts, and low antibacterial activity against P. Aeruginosa and S. Aureus at concentrations of up to 20 mg/ml. It could potentially further be investigated for similar uses as suxamethonium chloride, a muscle relaxant drug.
Keywords: choline chloride, betaine hydrochloride, carbonyldiimidazole, HPLC, antimicrobial, cytotoxicity
Published in DiRROS: 07.08.2024; Views: 206; Downloads: 285
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Abstract: Background. During the period of fetal development, myelination plays a key role and follows specific time and spa-tial sequences. The water content in the brain is inversely proportional to myelination – the more myelinated the brain, the lower the water content in it. The diffusion of water molecules can be quantitatively assessed using the apparent diffusion coefficient (ADC). We were interested in whether, by determining the ADC values, we could quantitatively evaluate the development of the fetal brain. Patients and methods. The study included 42 fetuses with gestational age 25 to 35 weeks. We manually selected 13 regions on diffusion-weighted images. Statistically significant differences between ADC values were checked using one-way analysis of variance and Tukey’s post hoc test. The relationship between the ADC values and the gestational age of the fetuses was then assessed using linear regression. Results. The average gestational age of the fetuses was 29.8 ± 2.4 weeks. ADC values in the thalami, pons and cerebellum differed significantly among each other and from the ADC values in other brain regions. In the thalami, pons and cerebellum, linear regression showed a significant decrease in ADC values with increasing gestational age. Conclusions. ADC values change with the increasing gestational age of the fetus and differ among different brain regions. In the pons, cerebellum and thalami, the ADC coefficient could be used as a biomarker of fetal brain matura-tion since ADC values decrease linearly with increasing gestational age.
Keywords: myelination, fetal brain maturation, ADC, biomarker, diffusion-weighted imaging, diffusion
Published in DiRROS: 25.07.2024; Views: 217; Downloads: 166
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Abstract: To address the decline in biodiversity, international cooperation in monitoring of threatened species is needed. Citizen science can play a crucial role in achieving this challenging goal, but most citizen science projects have been established at national or regional scales. Here we report on the establishment and initial findings of the European Stag Beetle Monitoring Network (ESBMN), an international network of stag beetle (Lucanus cervus) monitoring schemes using the same protocol. The network, started in 2016, currently includes 14 countries (see results) but with a strong variation in output regarding the number of transects (148 successful transects in total) and transect walks (1735). We found differences across European regions in the number of stag beetles recorded, related to phenology and temperature, but not for time of transect start. Furthermore, the initial experiences of the ESBMN regarding international cooperation, citizen science approach, and drop-out of volunteers is discussed. An international standardised protocol that allows some local variation is essential for international collaboration and data management, and analysis is best performed at the international level, whereas recruiting, training, and maintaining volunteers is best organised locally. In conclusion, we appeal for more joint international citizen science-based monitoring initiatives assisting international red-listing and conservation actions.
Published in DiRROS: 19.07.2024; Views: 228; Downloads: 172
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Abstract: CRISPR-Cas9 technology has emerged as a promising tool for genetic engineering of Streptomyces strains. However, in practice, numerous technical hurdles have yet to be overcome when developing robust editing procedures. Here, we developed an extension of the CRISPR-Cas toolbox, a simple and reliable cas9 monitoring tool with transcriptional fusion of cas9 nuclease to a beta glucuronidase (gusA) visual reporter gene. The Cas9-SD-GusA tool enables in situ identification of cells expressing Cas9 nuclease following the introduction of the plasmid carrying the CRISPR-Cas9 machinery. Remarkably, when the Cas9-SD-GusA system was applied under optimal conditions, 100% of the colonies displaying GusA activity carried the target genotype. In contrast, it was shown that the cas9 sequence had undergone major recombination events in the colonies that did not exhibit GusA activity, giving rise to “escaper colonies” carrying unedited genotype. Our approach allows a simple detection of “escaper” phenotype and serves as an efficient CRISPR-Cas9 optimisation tool.
Keywords: CRISPR-Cas9, gusA visual screening, "CRISPR escaper colonies", Streptomyces
Published in DiRROS: 17.07.2024; Views: 182; Downloads: 156
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Abstract: Cationic charge has been widely used to increase polymer adsorption and flocculation of dispersions or to provide antimicrobial activity. In this work, cationization of hydroxyethyl cellulose (HEC) and polyvinyl alcohol (PVA) was achieved by covalently coupling betaine hydrochloride and choline chloride to the polymer backbones through carbonyl diimidazole (CDI) activation. Two approaches for activation were investigated. CDI in excess was used to activate the polymers’ hydroxyls followed by carbonate formation with choline chloride, or CDI was used to activate betaine hydrochloride, followed by ester formation with the polymers’ hydroxyls. The first approach led to a more significant cross-linking of PVA, but not of HEC, and the second approach successfully formed ester bonds. Cationic, nitrogen-bearing materials with varying degrees of substitution were obtained in moderate to high yields. These materials were analyzed by Fourier transform infrared spectroscopy, nuclear magnetic resonance, polyelectrolyte titration, and kaolin flocculation. Their dose-dependent effect on the growth of Staphylococcus aureus and Pseudomonas aeruginosa, and L929 mouse fibroblasts, was investigated. Significant differences were found between the choline- and betaine-containing polymers, and especially, the choline carbonate esters of HEC strongly inhibited the growth of S. aureus in vitro but were also cytotoxic to fibroblasts. Fibroblast cytotoxicity was also observed for betaine esters of PVA but not for those of HEC. The materials could potentially be used as antimicrobial agents for instance by coating surfaces, but more investigations into the interaction between cells and polysaccharides are necessary to clarify why and how bacterial and human cells are inhibited or killed by these derivatives, especially those containing choline.
Keywords: hydroxyethyl cellulose, polyvinyl alcohol, antimicrobial, S. aureus, P. aeruginosa, L929 mouse fibroblast, cationic polymer
Published in DiRROS: 12.07.2024; Views: 227; Downloads: 160
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