Oncogenic Mutation BRAF V600E Changes Phenotypic Behavior of THLE-2 Liver Cells through Alteration of Gene Expression

The accumulation of mutations in cancer driver genes, such as tumor suppressors or proto-oncogenes, affects cellular homeostasis. Disturbances in the mechanism controlling proliferation cause significant augmentation of cell growth and division due to the loss of sensitivity to the regulatory signals. Nowadays, an increasing number of cases of liver cancer are observed worldwide. Data provided by the International Cancer Genome Consortium (ICGC) have indicated many alterations within gene sequences, whose roles in tumor development are not well understood. A comprehensive analysis of liver cancer (virus-associated hepatocellular carcinoma) samples has identified new and rare mutations in B-Raf proto-oncogene (BRAF) in Japanese HCC patients, as well as BRAF V600E mutations in French HCC patients. However, their function in liver cancer has never been investigated. Here, using functional analysis and next generation sequencing, we demonstrate the tumorigenic effect of BRAF V600E on hepatocytes (THLE-2 cell line). Moreover, we identified genes such as BMP6, CXCL11, IL1B, TBX21, RSAD2, MMP10, and SERPIND1, which are possibly regulated by the BRAF V600E-mediated, mitogen-activated protein kinases/extracellular signal-regulated kinases (MAPK/ERK) signaling pathway. Through several functional assays, we demonstrate that BRAF L537M, D594A, and E648G mutations alone are not pathogenic in liver cancer. The investigation of genome mutations and the determination of their impact on cellular processes and functions is crucial to unraveling the molecular mechanisms of liver cancer development.     

Reactions of TATB-Based Explosive with Molten Metal

The reactions of combustion products (CO, H₂O) from the insensitive high explosive LX-17 (92.5 wt% 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), 7.5 wt% Kel-F 800 binder) with molten metal (75 a%Nd, 25 a% Fe) were studied, to determine their contribution to the energy release rate of deflagrating LX-17, Kinetic data taken with gas mixtures of CO and H₂O, and larger-scale tests with LX-17, showed that the reactions were slow and incomplete and that there was no significant contribution to the energy release rate. From the tests with JX-17, the effective flame temperature and burn velocity were dependent on confinement of gas products. LX-17 preheated to 500 K - 510 K showed effective flame temperatures of 1100 K - 1400 K and burn rates of 0.08–0.11 mm/s, depending on the extent of gas confinement by the molten metal.     

Microbiologically Influenced Corrosion of copper in potable water installations – a European project review

Copper tubes are considered as material of choice for most domestic and institutional plumbing requirements. However, to a few instances problems have arisen which were shown to involve microbiological activity. The BRITE/EURAM Project “New Types of Corrosion Impairing the Reliability of Copper in Potable Water Caused by Microorganisms” (Contract-No. BREU-CT 91-0452) was launched to examine the interactions between microorganisms and their secreted products and a copper tube surface involving a cross-disciplinary consortium. A review of this project is reported in this contribution. Based upon chemical analysis of biofilms from failed copper tubes, it was possible to develop model biopolymers of defined composition and well characterised surface adsorption properties to establish suitable electrochemical test procedures. Culture biopolymers showing similar chemical compositions could be produced from a range of copper-pitting-associated bacteria. It was possible to demonstrate cation selective behaviour by layers of these relevant model and culture biopolymers. Two linked copper electrodes, one hare and the other coated with a cation selective biopolymer, were shown to establish a corrosion element. The covered areas acted as the cathode whilst the bare areas were anodic. This was also seen in single metal samples with disrupted polymer coatings giving “bare” patches. In anodic areas the corrosion follows a chloride induced mechanism leading to repassivation of the surface. This could also be demonstrated in the original potable water taken from an institutional building affected by Microbially Influenced Corrosion (MIC). Sulphate ions inhibit this expected passivation process. The basic corrosion process appears to follow the chloride model, but this can become overshadowed by the effects of additional anions such as sulphate and bicarbonate.     

Laser Doppler perfusion imaging by dynamic light scattering

A laser Doppler perfusion imaging technique based on dynamic light scattering in tissue is reported. When a laser beam sequentially scans the tissue (maximal area approximately 12 cm×12 cm), moving blood cells generate Doppler components in the backscattered light. A fraction of this light is detected by a remote photodiode and converted into an electrical signal. In the signal processor, a signal proportional to the tissue perfusion at each measurement point is calculated and stored. When the scanning procedure is completed, the system generates a color-coded perfusion image on a monitor. A perfusion image is typically built up of data from 4096 measurement sites, recorded during a time period of 4 min. This image has a spatial resolution of about 2 mm. A theory for the system inherent amplification factor dependence on the distance between individual measurement points and detector is proposed and correction measures are presented. Performance results for the laser Doppler perfusion imager obtained with a flow simulator are presented. The advantages of the method are discussed     

Pulsed n.m.r. of a SBS ‘macroscopic single crystal’

Pulsed n.m.r. T₁, T₂ and T_1? results are reported for a macroscopic single crystal of styrene—butadiene—styrene copolymer, recorded as a function of the angle between the extrusion axis of the sample and the magnetic field direction. The data confirm the absence of molecular orientation in either component of the copolymer. T₁ and T_1? results indicate a coupling via spin diffusion, between the polystyrene and polybutadiene regions. These spin diffusion effects are analysed in terms of a simple model, presented earlier, which demonstrates a stronger spin diffusion coupling in the rotating frame than in the laboratory frame.     

Deflagration of HMX‐Based Explosives at High Temperatures and Pressures

We measure the deflagration behavior of energetic materials at extreme conditions (up to 520 K and 1 GPa) in the LLNL High Pressure Strand Burner, thereby obtaining reaction rate data for prediction of violence of thermal explosions. The apparatus provides both temporal pressure history and flame time‐of‐arrival information during deflagration, allowing direct calculation of deflagration rate as a function of pressure. Samples may be heated before testing. Here we report the deflagration behavior of several HMX‐based explosives at pressures of 10–600 MPa and temperatures of 300–460 K. We find that formulation details are very important to overall deflagration behavior. Formulations with high binder content (≥15 wt%) deflagrate smoothly over the entire pressure range regardless of particle size, with a larger particle size distribution leading to a slower reaction. The deflagration follows a power law function with the pressure exponent being unity. Formulations with lower binder content (≤10 wt% or less) show physical deconsolidation at pressures over 100–200 MPA, with transition to a rapid erratic deflagration 10–100 times faster. High temperatures have a relatively minor effect on the deflagration rate until the HMX β→δ phase transition occurs, after which the deflagration rate increases by more than a factor of 10.     

Hybrid organic–inorganic materials based on polypyrrole and 1,3-dithiole-2-thione-4,5-dithiolate (DMIT) containing dianions

The synthesis of hybrid materials by electropolymerization of pyrrole and inorganic complexes based on the DMIT ligand (1,3-dithiole-2-thione-4,5-dithiolate), e.g. [NEt₄]₂[M(DMIT) _n ] (M = Ni, Pd or Pd, n = 2; M = Sn, n = 3], in acetonitrile solution is reported. Spectroscopic data showed that DMIT-containing anions, [M(DMIT) _n ]²⁻, were inserted into the polypyrrole framework without chemical modification during the electropolymerization process. Cyclic voltammetry showed that materials obtained were electroactive, undergoing redox processes related to both the conducting polymer and the counteranions. The electrochemical results also suggest that, in the case of the transition metal containing films, the counteranions are not trapped in the PPy matrix but undergo anion exchange during the redox cycle of PPy. However, an opposite behaviour was observed with the film with [M(DMIT) _n ]²⁻. The films exhibit good thermal stabilities and have conductivity values expected for semiconductors. This study of these hybrid materials highlights the importance of targeting specific materials for specific applications.

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The domain structure of human receptor-associated protein. Protease sensitivity and guanidine HCl denaturation

The 39-kDa receptor-associated protein (RAP), a specialized chaperone for endocytic receptors of the low density lipoprotein receptor gene family, is a triplicate repeat sequence (residues 1-100, 101-200, and 201-323, respectively), with the three repeats having different functional roles. The goal of the present study was to use a combination of protease sensitivity and guanidine denaturation analyses to investigate whether human RAP correspondingly contained multiple structural domains. Protease sensitivity analysis using six proteolytic enzymes of varying specificity showed that RAP has two protease-resistant regions contained within repeat 1 (residues 15-94) and repeat 3 (residues 223-323). Guanidine denaturation analysis showed that RAP has two phases in its denaturation, an early denaturation transition at 0.6 M guanidine HCl, and a broad second transition between 1.0 and 3.0 M guanidine HCl. Analysis of the denaturation of the individual repeats showed that, despite the similarity in sequence and protease sensitivity between repeats 1 and 3, repeat 1 was a stable structure, with a sharp transition midpoint at 2.4 M guanidine HCl, while repeat 3 was relatively unstable, with a transition midpoint at 0.6 M guanidine HCl. Repeat 2 had a denaturation profile almost identical to that of repeat 3. Denaturation analysis of the contiguous repeats 1 and 2 (residues 1-210) indicated that repeats 1 and 2 probably interact to form one structural domain represented by the broad transition, while repeat 3 constitutes a separate domain represented by the early transition. A two-domain model of RAP three-dimensional structure is proposed that integrates both structural and functional information, in which a helical segment from repeat 2 interacts with the known three-helix bundle of repeat 1 to form a four-helix bundle structural domain, while repeat 3 forms the other structural domain.     

Metabolomic profiling can differentiate between bactericidal effects of free and polymer bound halogen

The effects of two halogenated compounds (sodium hypochlorite and N‐halamine polymers) on the Escherichia coli metabolome were investigated. Changes in the intracellular metabolite pools of bacterial cells treated with different formulations of these compounds were analysed using FTIR (Fourier Transform Infra Red) spectroscopy and LC‐MS (Liquid Chromatography‐Mass Spectroscopy). Principal component analysis was used to generate metabolic profiles of the intracellular metabolites to investigate the effect of sublethal concentrations on the metabolome of treated cells. The effect of treatment with sodium hypochlorite was quantitatively dependent on the exposure time. The resulting metabolic profiles supported our previous hypothesis that the mode of action of some halogenated compounds, such as N‐halamine polymers, can be initiated by release of halogen ions into the aqueous environment, in addition to direct contact between the solid polymer material and the bacterial cells. Moreover, the metabolic profiles were able to differentiate between the effect of free and polymer‐bound halogen. Our metabolomic approach was used for hypothesis generation to distinguish apparently different bactericidal effects of free and polymer‐bound halogen. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011