Realizing the AF4-UV-SAXS on-line coupling on protein and antibodies using high flux synchrotron radiation at the CoSAXS beamline, MAX IV.

In this paper, we demonstrate the coupling of synchrotron small angle X-ray scattering (SAXS) to asymmetrical flow-field flow fractionation (AF4) for protein characterization. To the best of our knowledge, this is the first time AF4 is successfully coupled to a synchrotron for on-line measurements on proteins. This coupling has potentially high impact, as it opens the possibility to characterize individual constituents of sensitive and/or complex samples, not suited for separation using other techniques, and for low electron density samples where high X-ray flux is required, e.g., biomolecules and biologics. AF4 fractionates complex samples in native or close to native environment, with low shear forces and system surface area. Many orders of magnitude in size can be fractionated in one measurement, without having to reconfigure the experimental setup. We report AF4 fractionations with correlated UV and statistically adequate SAXS data of bovine serum albumin and a monoclonal antibody and evaluate SAXS data recorded for the two protein systems.

Effects of acute stress provocation on cortisol levels, zonulin and inflammatory markers in low- and high-stressed men.

The virtual version of the Trier Social Stress Test (V-TSST) is an effective and standardized tool for social stress induction. This study aimed to examine gut permeability and physiological and inflammatory markers of reactivity to acute psychosocial stress. Forty young men were classified as high-stressed (HIGHS) or low-stressed (LOWS) according to the Shirom-Melamed Burnout Questionnaire. Cardiovascular reactivity and gut dysfunction were studied along with cortisol, zonulin and cytokines. Gut permeability was shown to be affected within one hour after the psychosocial stress induction, and shown to be dependent on age. Interleukin-6 increased with time, most pronounced at the end of the one-hour recovery after V-TSST, and was positively correlated to age. HIGHS experienced more abdominal dysfunction compared to LOWS. In conclusion, this study is the first to show fluctuations in gut permeability after psychosocial stress induction. This was partly associated with changes in inflammatory markers.