Mechanisms of connective tissue formation and blocks of mitogen activated protein kinase

Ninety male Wistar rats were selected under the “Guide for the Care and Use of Laboratory Animals” for skin-muscle wound models. Three groups of animals were examined respectively for inoculation of inhibitor of p38 MAPK (mitogen activated protein kinase) SB 203580 and JNK inhibitor SP 600125, and a control. Light microscopy, immunohistochemistry, and tensometry revealed that the inhibition of p38 or JNK cascades have modified the formation of the connective tissue scar. The degree of connective tissue growth in the area of surgical wound had been significantly reduced by the end of observation (30 d) as the SB 203580 was applied (% volume of collagen 43.60 (41.05 – 60.15) vs. 73.54 (66.87 – 78.01) in control, p = 0.002). Conversely, when we have applied the JNK blocker, the density of collagen in scar tissue increased (78.14 (72.77 – 81.14), p = 0.022 vs. control). SB203580 inhibits the expression of p38, c-Jun and c-Fos. When we have used the JNK blocker, the expression of c-Fos and c-Jun decreased, but the expression of p38 increased. This determines the high functional activity of fibroblasts after using SP 600125. Obtained results show the importance of studying regulators of cell differentiation as potential drugs, which significantly affect the outcome of the pathological processes.     

Regulation of Ribosomal Protein Synthesis in Mycobacteria: The Autogenous Control of rpsO

The autogenous regulation of ribosomal protein (r-protein) synthesis plays a key role in maintaining the stoichiometry of ribosomal components in bacteria. In this work, taking the rpsO gene as a classic example, we addressed for the first time the in vivo regulation of r-protein synthesis in the mycobacteria M. smegmatis (Msm) and M. tuberculosis (Mtb). We used a strategy based on chromosomally integrated reporters under the control of the rpsO regulatory regions and the ectopic expression of Msm S15 to measure its impact on the reporter expression. Because the use of E. coli as a host appeared inefficient, a fluorescent reporter system was developed by inserting Msm or Mtb rpsO-egfp fusions into the Msm chromosome and expressing Msm S15 or E. coli S15 in trans from a novel replicative shuttle vector, pAMYC. The results of the eGFP expression measurements in Msm cells provided evidence that the rpsO gene in Msm and Mtb was feedback-regulated at the translation level. The mutagenic analysis showed that the folding of Msm rpsO 5′UTR in a pseudoknot appeared crucial for repression by both Msm S15 and E. coli S15, thus indicating a striking resemblance of the rpsO feedback control in mycobacteria and in E. coli.     

Damping,tensile, and impact properties of superelastic shape memory alloy (SMA) fiber-reinforced polymer composites

The potential of superelastic shape memory alloy (SMA) fibers to enhance the damping capacity and toughness of a thermoset polymer matrix was evaluated. A single-fiber winder was designed and built to manufacture a pre-form consisting of 102 μm diameter SMA fibers aligned parallel to each other. This pre-form was loaded to varying amounts of pre-strain and impregnated with vinyl ester to manufacture SMA fiber composites with 20% fiber volume fraction. The composites were tested using a Differential Scanning Calorimeter (DSC) and a Dynamic Mechanical Analysis (DMA), to evaluate the improvement in damping capacity of the polymer matrix due to the SMA fibers. Tensile and instrumented impact testing were carried out to evaluate improvements in mechanical properties and toughness of the composites. Appreciable improvement was observed in damping, tensile, and impact properties of the polymer matrix due to reinforcement with superelastic SMA fibers, highlighting the advantages of their use in polymer composites.     

Epoxide Speciation and Functional Group Distribution in Graphene Oxide Paper‐Like Materials

The electronic structure and chemical bonding of three differently prepared samples of graphene oxide paper‐like sheets are studied. Two are created by water filtration of fully oxidized graphene sheets, although one is later intercalated with dodecylamine. The third is created by reducing graphene oxide with hydrazine hydrate. The spectroscopic fingerprints of the aligned epoxide functional groups that unzip the carbon basal plane are found. This unzipping appears to be a result of aging, and the extent to which the basal plane is unzipped can be controlled via the preparation method. In particular, reduction with hydrazine enhances line defect formation, whereas intercalation inhibits the process.The hydroxyl functional group also has a tendency to gather in zones of dense oxidation on the carbon basal plane, a predilection that is not shared by the other prominent functional group species. Finally, the non‐functionalized carbon sites exhibit very similar bonding despite the increase in the sp²/sp³ ratio, confirming that reduction alone is insufficient for producing pristine graphene from graphene oxide. These results are obtained by directly probing the electronic structure of the graphene oxide samples via X‐ray absorption near‐edge structure spectroscopy (XANES) and resonant X‐ray emission spectroscopy (RXES). This work has important significance for the development of graphene oxide as a band gap‐engineered electronic material, as preparation methodology strongly affects not only the initial condition of the sample, but how the electronic structure evolves over time.     

A new cytotoxic fatty acid (5<Emphasis Type="Italic">Z</Emphasis>,9<Emphasis Type="Italic">Z</Emphasis>)-22-methyl-5,9-tetracosadienoic acid and the sterols from the far Eastern sponge <Emphasis Type="Italic">Geodinella robusta</Emphasis>

A new fatty acid, (5Z,9Z)-22-methyl-5,9-tetracosadienoic acid (1a), and a rare fatty acid, (5Z,9Z)-23-methyl-5,9-tetracosadienoic acid (2a), the predominant constituents of the free fatty acid fraction from the lipids of the sponge Geodinella robusta, were isolated and partly separated by reversed phase high-performance liquid chromatography, followed by multifold crystallization from MeOH to give 1a and 2a in 70% and 60% purity, respectively. These fatty acids were identified as (5Z,9Z)-22-and (5Z,9Z)-23-methyl-5,9-tetracosadienoic acids by nuclear magnetic resonance techniques, including distortionless enhancement by polarization transfer, heteronuclear multiple quantum connectivity, and correlation spectroscopy experiments, as well as from mass-spectrometric data for their methyl esters, the methyl esters of their perhydro derivatives, and their pyrrolidides. Mixtures of 1a and 2a showed cytotoxic activity against mouse Ehrlich carcinoma cells and a hemolytic effect on mouse erythrocytes. The sterol fraction from the same sponge was analyzed by gas liquid chromatography mass spectrometry, and 24-methylenecholesterol was identified as a main constituent of this fraction. The implications of the co-occurrence of membranolytic long-chain fatty acids and 24-methylenecholesterol as a main membrane sterol are discussed in terms of the phenomenon of biochemical coordination.     

Working Chamber for Processing Foodstuffs by a Complex Action of Strong Pulsed Electric Fields

Requirements for working chambers intended for the sterilization of foodstuffs by high-voltage pulses are specified. Cassette- and flow-chamber designs are described. The limiting pulse voltage (U 120 kV) and electric-field intensity (E 120 kV/cm) achieved in the chambers tested are given. The dependence of the lifetime of the working chambers on the operating electric-field intensity and on the pulse duration is estimated.     

Analysis by capillary electrophoresis of the kinetics of charge ladder formation for bovine carbonic anhydrase

A series of charge ladders of bovine carbonic anhydrase II were synthesized and the relative abundances of the rungs analyzed by capillary electrophoresis as a function of the quantity of acylating agent used. A simulation that models the kinetics of formation of the members of the charge ladders is described. The observed rate constants decreased as the extent of acylation increased. These rate constants correlated adequately with theoretical rate constants calculated using Debye-Hückel theory. The data are compatible with, but do not demand, a model for the formation of this charge ladder in which all unacetylated amino groups in each rung have indistinguishable reactivity and in which the reactivity of the amines in each rung decreases as the net charge on the protein increases; in this model, decreased reactivity is due to increased extent of protonation. This agreement between experiment and model suggests that the charge shielding that results from an ionic strength of 130 mM is not sufficient to suppress the influence of the increasingly negative charge of the protein with acetylation on the extent of protonation of Lys epsilon-NH2 groups.