Proteome profiling by label‐free mass spectrometry reveals differentiated response of Campylobacter jejuni 81–176 to sublethal concentrations of bile acids.

Purpose Bile acids are crucial components of the intestinal antimicrobial defense and represent a significant stress factor for enteric pathogens. Adaptation processes of Campylobacter jejuni to this hostile environment are analyzed in this study by a proteomic approach. Experimental design Proteome profiling by label-free mass spectrometry (SWATH-MS) has been used to characterize the adaptation of C. jejuni to sublethal concentrations of seven bile acids. Results The bile acids with the lowest inhibitory concentration (IC50), deoxycholic and chenodeoxycholic acid, induce the most significant proteome changes. Overall a downregulation of all basic biosynthetic pathways and a general decrease in the transcription machinery are found. Concurrently, an induction of factors involved in detoxification of reactive oxygen species, protein folding, and bile acid exporting efflux pumps is detected. Exposure to deoxycholic and chenodeoxycholic acid results in an increased expression of components of the more energy-efficient aerobic respiration pathway, while the anaerobic branches of the electron transport chain are down-expressed. Conclusions and clinical relevance The results show that C. jejuni has a differentiated system of adaptation to bile acid stresses. The findings enhance the understanding of the pathogenesis of campylobacteriosis, especially for survival of C. jejuni in the human intestine, and may provide clues to future medical treatment

Beta-Tricalcium Phosphate Resorption by Monocytes in Biphasic Calcium Phosphate: An In Vitro Study

A macroporous biphasic calcium phosphate (BCP) of 60.7% carbonated dense non-porous hydroxyapatite (HA)/39.3% dense microporous ß-tricalcium phosphate (ß-TCP) was immersed during 15 days in a supplemented a-MEM (minimal essential medium) solution with and without dog bone marrow cells obtained by punction. The aim of the study was to demonstrate the time-related changes in the BCP fractions by means of X -ray diffraction, infrared spectroscopy and scanning electron microscopy, and to investigate the cell populations. The HA/ß-TCP ratios varied according to immersion duration and cell presence. If any, there was a slight preponderance of ß-TCP dissolution over that of HA. The dissolution rate was much lower in the presence of cells. Cell-mediated resorption was observed only in ß-TCP sites. The implicated small round-shaped cells of about 30 I\u27m were located in resorption lacunae, presented numerous short filopodia and a ruffled border faced towards the material to resorb. They did not undergo fusion with other cells but lost, on about day 15, their ruffled border. Then blast-cells highly involved in matrix secretion and mineralization appeared. There seems to be ample evidence that the clast-cells are specific monocytes which resorb ß-TCP under these in vitro conditions. To elucidate their exact nature, functions and fate, further long-range in vitro studies conducted under standardized conditions are needed

European women’s views on specialist counselling for female survivors of domestic violence and abuse

Counselling for female survivors of domestic violence as practiced in five European countries (United Kingdom - UK, Bulgaria, Italy, the Netherlands and Latvia) was qualitatively explored by researchers in the UK, Germany and Portugal over two years. The effectiveness of current practice was analysed using data from 60 face-to-face interviews with clients who had received counselling. Findings revealed that regardless of which counselling model or approach is used, the effectiveness of specialist domestic violence counselling is dependent upon a positive therapeutic alliance built on mutual trust and respect and, crucially, an understanding of the dynamics of domestic violence and abuse provided by highly qualified counsellors who have received domestic violence training. This article concludes by offering recommendations to inform future funding and policy decisions and avenues for future research

Heating of Calcium Phosphate Crystals: Morphological Consequences and Biological Implications

Sintering hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP) affects the chemical composition, the crystallinity, and the morphological features as demonstrated by means of X-ray diffraction (XRD) , infrared spectroscopy (IR), and scanning electron microscopy (SEM). When heated to 1230°C, 16.7% of HA had decomposed to ß-TCP. SEM investigations showed homogeneous, sharp angular polyhedric blocks of 30 to 50 µm with rare surface pores. On heating at 1230°C, ß-TCP had entirely transformed to a-TCP. During sintering, the size of the powder grains increased and progressive bridging between the grains was observed. At 1230°C, a network within round-shaped polyhedric blocks of 50 to 90 µm was formed. In both, HA and IJ-TCP, surfaces were smooth. The chemical composition and the crystallinity of calcium phosphate ceramics determine their dissolution behavior and osteogenic properties. Nevertheless, their temperature dependent morphological features, such as, particle shape and size, surface texture, and porosity, as demonstrated in the present study, also influence the resorption rates , tissue responses, and wound healing duration. This should be emphasized more by clinicians in choosing an appropriate material for bone substitution

Chiral recognition for the complexation dynamics of β-cyclodextrin with the enantiomers of 2-naphthyl-1-ethanol

The focus of this study is to understand the origin of the chiral recognition for a host–guest system containing complexes with different stoichiometries. Each enantiomer of 2-naphthyl-1-ethanol forms two different 1:1 complexes with β-cyclodextrin, leading to the formation of three different 2:2 complexes. One of these 2:2 complexes leads to excimer emission of the guest. Fluorescence studies were employed to determine the binding isotherms for the 1:1 and 2:2 complexes. No chiral discrimination was directly observed for the formation of the 1:1 complexes, while higher equilibrium constants (29% from binding isotherms and 40% from kinetic studies) were observed for the formation of the 2:2 complexes with (R)-2-naphthyl-1-ethanol when compared to the formation of the 2:2 complexes formed from (S)-2-naphthyl-1-ethanol. The relaxation kinetics was studied using stopped-flow experiments. The formation of the 2:2 complexes was followed by detecting the excimer emission from one of the 2:2 complexes. The relaxation kinetics was faster for (S)-2-naphthyl-1-ethanol, where a higher dissociation rate constant, by 47%, was observed, suggesting that the chiral discrimination occurs because the interaction between two cyclodextrins is more favorable for the complexes containing (R)-2-naphthyl-1-ethanol when compared to (S)-2-naphthyl-1-ethanol. The same overall equilibrium constants were observed for the 1:1 complexes with both enantiomers showing that at a given cyclodextrin concentration the sum of the two types of 1:1 complexes is the same for both enantiomers. However, analysis of the binding isotherms indicates that the ratio between the two different 1:1 complexes for each enantiomer was different for (R)- and (S)-2-naphthyl-1-ethanol