Fast photochemical oxidation of proteins for comparing structures of protein-ligand complexes: the calmodulin-peptide model system

Fast photochemical oxidation of proteins (FPOP) is a mass spectrometry-based protein footprinting method that modifies proteins on the microsecond time scale. Highly reactive (?)OH, produced by laser photolysis of hydrogen peroxide, oxidatively modifies the side chains of approximately one-half the common amino acids on this time scale. Because of the short labeling exposure, only solvent-accessible residues are sampled. Quantification of the modification extent for the apo and holo states of a protein-ligand complex provides structurally sensitive information at the amino-acid level to compare the structures of unknown protein complexes with known ones. We report here the use of FPOP to monitor the structural changes of calmodulin in its established binding to M13 of the skeletal muscle myosin light chain kinase. We use the outcome to establish the unknown structures resulting from binding with melittin and mastoparan. The structural comparison follows a comprehensive examination of the extent of FPOP modifications as measured by proteolysis and LC-MS/MS for each protein-ligand equilibrium. The results not only show that the three calmodulin-peptide complexes have similar structures but also reveal those regions of the protein that became more or less solvent-accessible upon binding. This approach has the potential for relatively high throughput, information-dense characterization of a series of protein-ligand complexes in biochemistry and drug discovery when the structure of one reference complex is known, as is the case for calmodulin and M13 of the skeletal muscle myosin light chain kinase, and the structures of related complexes are not.     

Modern gold deportments and its application to industry

Modern gold deportment studies include physical, chemical and mineralogical assessments, combined to obtain a full understanding of the nature and variability of gold in a resource. The objective is to provide information which will allow cost effective and practical processing by informing decisions regarding resource evaluation, mining method and extraction process optimization.The distribution of gold, based on speciation, grain size and mode of occurrence (liberation, exposure, and mineral association) is quantitatively determined by means of automated Scanning Electron Microscopic Techniques (QEMSCAN/MLA). Furthermore, general mineralogical characterization is undertaken in order to characterize the gangue components; with special emphasis on deleterious characteristics of the ore (e.g. cyanide consumers such as secondary Cu-species, preg-robbers/borrowers, passivation due to Sb-minerals or As-minerals and oxygen consumers such as pyrrhotite/marcasite).Predictions based on the mineralogical observations are confirmed by physical and chemical testwork. These include grading analyses, gravity separation, direct cyanidation, and diagnostic (sequential) leach tests.     

Development of a new CBR-based platform for human contamination emergency situations

In the case of a radiological emergency situation, involving accidental human exposure, it is necessary to establish as soon as possible a dosimetry evaluation. In most cases, this evaluation is based on numerical representations and models of the victims. Unfortunately, personalised and realistic human representations are often unavailable for the exposed subjects. Hence, existing models like the 'Reference Man' representative of the average male individual are used. However, the accuracy of the treatment depends on the similarity of the phantom to the victim. The EquiVox platform (Research of Equivalent Voxel phantom) developed in this work uses the case-based reasoning principles to retrieve, from a set of existing phantoms, the most adapted one to represent the victim. This paper introduces the EquiVox platform and gives the example of in vivo lung monitoring optimisation to prove its efficiency in choosing the right model. It also presents the artificial neural network tools being developed to adapt the model to the victim.     

Housing and the Material Imagination – Earth,Fire, Air and Water

This paper focuses on the possibilities of the material imagination as a theoretical and practical lens for contemporary housing research. The emphasis is on housing/home as complex material cultural assemblages interwoven across the four key ancient elements: earth, air, fire and water. The principle behind the material imagination is that “matter” – which we are immersed in and indeed ourselves composed of – is important, indeed underpins everything, and yet is typically rendered invisible within housing theory and research. As a critical response to social scientific engagement – “a needed radical corrective” – the potential of the material imagination for housing theory and practice is considered in ways that purposively attend to the elemental dimensions of housing as dynamic, fluid environments comprised of living matter. Suggestions for taking this approach forward through empirical housing studies are outlined.     

Browning Inhibition and Textural Changes of Pre-Peeled Potatoes Caused by Anaerobic Conditions

Sulphite treatment is often used for inhibition of enzymatic browning of pre-peeled potatoes. Introduction of CO₂ or N₂ gases in the immersion water was investigated as an alternative to sulphite. The samples were stored at 4 °C. Daily introduction of the gases reduced the O₂ content from approx. 8.8 mg/L (measured at 20 °C) to 0.2-1.9 mg/L during the immersion period. The CO₂ treatment inhibited the browning completely and N₂ treatment did not. It is assumed that this is due to the lower pH in the CO₂ water. When CO₂ was added only one time at the start of the experiment, it also inhibited discoloration, but the immersion water developed a weak brown colour. Both the CO₂ and the N₂ treatment induced hardening in the outer potato tuber tissue after cooking after 4-7 d of storage, as did Na₂SO₃ solutions.     

Statistical analysis of the quantal basis of secretory granule formation

ABSTRACT The size distribution of vesicles exocytosed from secretory cells displays quantal nature, vesicle volume is periodic multi‐modal, suggesting that these heterogeneous vesicles are aggregate sums of a variable number of homogeneous basic granules. Whether heterogeneity is a lumping‐together artifact of the measurement or an inherent intra‐cell feature of the vesicles is an unresolved question. Recent empirical evidence will be provided for the quantal nature of intra‐cell vesicle volume, supporting the controversial paradigm of homotypic fusion: basic cytoplasmic granules fuse with each other to create heterogeneously sized vesicles. An EM‐algorithm‐based method is presented for the conversion of multi‐modal to quantal data that provides as by‐product estimates of means and variances of basic granule packaging. Microsc. Res. Tech. 77:1–10, 2014. © 2013 Wiley Periodicals, Inc.     

Retropubic and perineal approach: plea for perineal radical prostatectomy

OBJECTIVES: Two surgical approaches are proposed for radical prostatectomy: the retropubic route and the perineal route. We compared the surgical, oncological and functional aspects of these two approaches and present arguments suggesting that the perineal approach is the preferred approach for radical prostatectomy. MATERIAL AND METHODS: 55 retropubic radical prostatectomies were retrospectively compared to 55 perineal radical prostatectomies and performed between March 1992 to December 1995. The clinical TNM, preoperative PSA, results of 6 systematized intrarectal biopsies, operating time, intraoperative bleeding, number of patients transfused and number of packed cell units per patient transfused, medical and surgical complications, catheterization time and length of hospital stay, incidence of urethrovesical anastomosis leak and stenosis, analysis of the prostatectomy specimen, course of PSA, continence and erection were studied. RESULTS: Statistically significant differences were observed for the retropubic and perineal approaches, respectively: preoperative PSA (24 vs 15 ng/mL), intraoperative bleeding (2664 vs 1071 mL), number of patients transfused (91% vs 28%), number of packed cell units per patient transfused (3.9 vs 2.7), medical and surgical complications (56.9 vs 29.1%), anastomotic leak (24.1 vs 7.2%), anastomotic stenosis (31.5 vs 1.8%), duration of catheterization (18 vs 13 days) and length of hospital stay (14 vs 8 days). At 2 years, PSA remained less than 0.5 ng/mL in both groups. CONCLUSION: Even taking the learning period into account, the perineal approach provides the same results as the retropubic approach in terms of functional and oncological parameters, with a simpler postoperative course for patient.     

Decompression of the optic nerve sheath

Optic nerve sheath decompression (ONSD) has become a more frequently performed surgical procedure in recent years. We describe the surgical techniques and complications and we detail the indications of ONSD in pseudotumor cerebri, ischemic optic neuropathy due to arteriosclerosis and other etiologies under investigation. With a 2% risk of postoperative blindness, this procedure must be indicated only in case of severe visual loss and performed by surgeon experienced to orbital surgery.