Characterization of the human serum depletome by label-free shotgun proteomics

While it is known that immunoaffinity depletion of abundant proteins in serum removes additional proteins beyond those targeted, there has been little characterization of the co-depleted proteins in the high abundant fraction, which we refer to here as the "depletome". We present evidence of co-depletion of non-targeted proteins in human serum using a top-20 immunodepletion column, as shown by label-free liquid chromatography mass spectrometry (LC-MS(E)) profiling. This led to identification of 147 proteins which were specific for this fraction and comprised proteins with functions predominantly in binding and transport of nucleotides, metal ions, carbohydrates and lipids. These results suggest that further studies on this commonly ignored serum fraction may provide new insights into clinical proteomics.     

Quantitative determination of small selenium species in human serum by HPLC/ICPMS following a protein-removal, pre-concentration procedure

Protein precipitation was incorporated into a sample preparation method for the quantitative determination of small "non-protein" selenium species in human serum by high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC/ICPMS). The advantages of cleaner matrix and concomitant concentration of the small compounds result in quantification limits in the native serum at the sub-micrograms Se per litre level. Spiking experiments with methyl 2-acetamido-2-deoxy-1-seleno-β-D-galactopyranoside (selenosugar 1), trimethylselenonium ion, selenomethionine, methylselenocysteine (MeSeCys) and selenate yielded recoveries from 73% to 103%. Selenite had a low recovery (44%), possibly owing to protein binding. The validated method was applied to serum samples from two volunteers before and after ingestion of a selenium food supplement. HPLC/ICPMS analysis showed, besides ingested selenate, the presence of selenosugar 1 and trace amounts of MeSeCys and methyl 2-amino-2-deoxy-1-seleno-β-D-galactopyranoside, which have not been reported in human serum before.     

Homogeneous Phase Copolymerizations of Vinylidene Fluoride and Hexafluoropropene in Supercritical Carbon Dioxide

Copolymerizations of vinylidene fluoride (VDF) and hexafluoropropene (HFP) were carried out in homogeneous phase with supercritical carbon dioxide up to complete VDF conversion using conventional peroxide initiators. The HFP monomer feed ratios, f_HFP, were varied between 0.65 and 0.20. Depending on f_HFP amorphous or semi‐crystalline copolymers were obtained. f_HFP also determines the minimum pressure required to allow for homogeneous phase reactions. For example, HFP‐rich copolymerizations in 70 wt.‐% CO₂ at 100 °C require a pressure of around 500 bar. Further, bulk copolymerizations in homogenous phase were feasible for f_HFP = 0.65 at 900 bar up to complete VDF conversion. Copolymerizations in the presence of perfluorinated hexyl iodide carried out at 75 °C gave access to low dispersity polymers. Due to homogeneous phase conditions the use of any surfactants or fluorinated cosolvent is avoided.

     

Radical protection by sunscreens in the infrared spectral range

One essential reason for skin ageing is the formation of free radicals by excessive or unprotected sun exposure. Recently, free radical generation in skin has been shown to appear not only after irradiation in the UV wavelength range but also in the infrared (IR) spectral range. Sunscreens are known to protect against radicals generated by UV radiation; however, no data exist for those generated by IR radiation. This paper has investigated four different, commercially available sunscreens and one COLIPA standard with regard to radical formation in the skin after IR irradiation, using electron paramagnetic resonance spectroscopy. The use of sunscreens has led to reduced amounts of radicals compared to untreated skin. Furthermore, absorption and scattering properties and the radical protection factor of the formulations were determined to investigate their influence on the radical protection of the skin. None of these formulations contained an optical absorber in the IR range. The protection efficiency of the sunscreens was shown as being induced by the high scattering properties of the sunscreens, as well as the antioxidants contained in the formulations.     

Crossover from normal to anomalous diffusion in systems of field-aligned dipolar particles

Using molecular dynamics simulations we investigate the translational dynamics of particles with dipolar interactions in homogenous external fields. For a broad range of concentrations, we find that the anisotropic, yet normal diffusive behavior characterizing weakly coupled systems becomes anomalous both parallel and perpendicular to the field at sufficiently high dipolar coupling and field strength. After the ballistic regime, chain formation first yields cagelike motion in all directions, followed by transient, mixed diffusive-superdiffusive behavior resulting from cooperative motion of the chains. The enhanced dynamics disappears only at higher densities close to crystallization.     

Brominated flame retardants in the European chemicals policy of REACH-Regulation and determination in materials

The EU REACH legislation will require the registration of 30,000 currently marketed chemicals, including the main commercial BFRs in use (Deca-BDE, HBCD and TBBP-A). Much of the data needed for registration are already available, thanks to risk assessments of continued production and use already undertaken in the EU. Within the authorisation, substitution by less hazardous chemicals is encouraged. Both qualitative and quantitative methods for the analysis of flame-retarded polymers are needed in order that the identity and concentration of the BFRs can be established and compliance with regulations including the RoHS Directive demonstrated. These are reviewed.     

Monolayer investigations on the bacterial amphiphile lipoteichoic acid and on lipoteichoic acid/dipalmitoyl-phosphatidylglycerol mixtures

Lipoteichoic acid (LTA) and mixtures of LTA with dipalmitoyldiphosphatidylglycerol (DPPG) were investigated with Langmuir-Blodgett techniques. In spite of its large hydrophilic portion LTA formed a monolayer when spread from a chloro-form/n-propanol/water system. In DPPG/LTA-mixed monolayers LTA influenced strongly the compression isotherms, indicating a stabilizing effect of LTA on DPPG monolayers. At higher concentrations of LTA phase separation was observed.     

Bursatella leachii Purple Ink Secretion Concentrate Exerts Cytotoxic Properties against Human Hepatocarcinoma Cell Line (HepG2): In Vitro and In Silico Studies

Liver cancer is a leading cause of cancer death globally. Marine mollusc-derived drugs have gained attention as potential natural-based anti-cancer agents to overcome the side effects caused by conventional chemotherapeutic drugs during cancer therapy. Using liquid chromatography-mass spectrometry, the main biomolecules in the purple ink secretion released by the sea hare, named Bursatella leachii (B. leachii), were identified as hectochlorin, malyngamide X, malyngolide S, bursatellin and lyngbyatoxin A. The cytotoxic effects of B. leachii ink concentrate against human hepatocarcinoma (HepG2) cells were determined to be dose- and time-dependent, and further exploration of the underlying mechanisms causing the programmed cell death (apoptosis) were performed. The expression of cleaved-caspase-8 and cleaved-caspase-3, key cysteine-aspartic proteases involved in the initiation and completion of the apoptosis process, appeared after HepG2 cell exposure to the B. leachii ink concentrate. The gene expression levels of pro-apoptotic BAX, TP53 and Cyclin D1 were increased after treatment with the B. leachii ink concentrate. Applying in silico approaches, the high scores predicted that bioactivities for the five compounds were protease and kinase inhibitors. The ADME and cytochrome profiles for the compounds were also predicted. Altogether, the B. leachii ink concentrate has high pro-apoptotic potentials, suggesting it as a promising safe natural product-based drug for the treatment of liver cancer.     

Matrix‐Free DNP‐Enhanced NMR Spectroscopy of Liposomes Using a Lipid‐Anchored Biradical

Magic‐angle spinning dynamic nuclear polarization (MAS‐DNP) has been proven to be a powerful technique to enhance the sensitivity of solid‐state NMR (SSNMR) in a wide range of systems. Here, we show that DNP can be used to polarize lipids using a lipid‐anchored polarizing agent. More specifically, we introduce a C16‐functionalized biradical, which allows localization of the polarizing agents in the lipid bilayer and DNP experiments to be performed in the absence of excess cryo‐protectant molecules (glycerol, dimethyl sulfoxide, etc.). This constitutes another original example of the matrix‐free DNP approach that we recently introduced.