Integrin α2β1 Mediates Tyrosine Phosphorylation of Vascular Endothelial Cadherin Induced by Invasive Breast Cancer Cells

The molecular mechanisms that regulate the endothelial response during transendothelial migration (TEM) of invasive cancer cells remain elusive. Tyrosine phosphorylation of vascular endothelial cadherin (VE-cad) has been implicated in the disruption of endothelial cell adherens junctions and in the diapedesis of metastatic cancer cells. We sought to determine the signaling mechanisms underlying the disruption of endothelial adherens junctions after the attachment of invasive breast cancer cells. Attachment of invasive breast cancer cells (MDA-MB-231) to human umbilical vein endothelial cells induced tyrosine phosphorylation of VE-cad, dissociation of β-catenin from VE-cad, and retraction of endothelial cells. Breast cancer cell-induced tyrosine phosphorylation of VE-cad was mediated by activation of the H-Ras/Raf/MEK/ERK signaling cascade and depended on the phosphorylation of endothelial myosin light chain (MLC). The inhibition of H-Ras or MLC in endothelial cells inhibited TEM of MDA-MB-231 cells. VE-cad tyrosine phosphorylation in endothelial cells induced by the attachment of MDA-MB-231 cells was mediated by MDA-MB-231 α₂β₁ integrin. Compared with highly invasive MDA-MB-231 breast cancer cells, weakly invasive MCF-7 breast cancer cells expressed lower levels of α₂β₁ integrin. TEM of MCF-7 as well as induction of VE-cad tyrosine phosphorylation and dissociation of β-catenin from the VE-cad complex by MCF-7 cells were lower than in MDA-MB-231 cells. These processes were restored when MCF-7 cells were treated with β₁-activating antibody. Moreover, the response of endothelial cells to the attachment of prostatic (PC-3) and ovarian (SKOV3) invasive cancer cells resembled the response to MDA-MB-231 cells. Our study showed that the MDA-MB-231 cell-induced disruption of endothelial adherens junction integrity is triggered by MDA-MB-231 cell α₂β₁ integrin and is mediated by H-Ras/MLC-induced tyrosine phosphorylation of VE-cad.     

Biodesulfurization of refractory organic sulfur compounds in fossil fuels

The stringent new regulations to lower sulfur content in fossil fuels require new economic and efficient methods for desulfurization of recalcitrant organic sulfur. Hydrodesulfurization of such compounds is very costly and requires high operating temperature and pressure. Biodesulfurization is a non-invasive approach that can specifically remove sulfur from refractory hydrocarbons under mild conditions and it can be potentially used in industrial desulfurization. Intensive research has been conducted in microbiology and molecular biology of the competent strains to increase their desulfurization activity; however, even the highest activity obtained is still insufficient to fulfill the industrial requirements. To improve the biodesulfurization efficiency, more work is needed in areas such as increasing specific desulfurization activity, hydrocarbon phase tolerance, sulfur removal at higher temperature, and isolating new strains for desulfurizing a broader range of sulfur compounds. This article comprehensively reviews and discusses key issues, advances and challenges for a competitive biodesulfurization process.     

A novel abundant family of retroposed elements (DAS-SINEs) in the nine-banded armadillo (Dasypus novemcinctus)

About half of the mammalian genome is composed of retroposons. Long interspersed elements (LINEs) and short interspersed elements (SINEs) are the most abundant repetitive elements and account for about 21% and 13% of the human genome, respectively. SINEs have been detected in all major mammalian lineages, except for the South American order Xenarthra, also termed Edentata (armadillos, anteaters, and sloths). Investigating this order, we discovered a novel high-copy-number family of tRNA derived SINEs in the nine-banded armadillo Dasypus novemcinctus, a species that successfully crossed the Central American land bridge to North America in the Pliocene. A specific computer algorithm was developed, and we detected and extracted 687 specific SINEs from databases. Termed DAS-SINEs, we further divided them into six distinct subfamilies. We extracted tRNA(Ala)-derived monomers, two types of dimers, and three subfamilies of chimeric fusion products of a tRNA(Ala) domain and an approximately 180-nt sequence of thus far unidentified origin. Comparisons of secondary structures of the DAS-SINEs' tRNA domains suggest selective pressure to maintain a tRNA-like D-arm structure in the respective founder RNAs, as shown by compensatory mutations. By analysis of subfamily-specific genetic variability, comparison of the proportion of direct repeats, and analysis of self-integrations as well as key events of dimerization and deletions or insertions, we were able to delineate the evolutionary history of the DAS-SINE subfamilies.     

Molecularly imprinted polymer cartridges coupled on-line with high performance liquid chromatography for simple and rapid analysis of dextromethorphan in human plasma samples

In this paper, a novel method is described for automated determination of dextromethorphan in biological fluids using molecularly imprinted solid-phase extraction (MISPE) as a sample clean-up technique combined with high performance liquid chromatography (HPLC). The water-compatible molecularly imprinted polymers (MIPs) were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, chloroform as porogen and dextromethorphan as template molecule. These imprinted polymers were used as solid-phase extraction sorbent for the extraction of dextromethorphan from human plasma samples. Various parameters affecting the extraction efficiency of the MIP cartridges were evaluated. The high selectivity of the sorbent coupled to the high performance liquid chromatographic system permitted a simple and rapid analysis of this drug in plasma samples with limits of detection (LOD) and quantification (LOQ) of 0.12 ng/mL and 0.35 ng/mL, respectively. The MIP selectivity was evaluated by analyzing of the dextromethorphan in presence of several substances with similar molecular structures and properties. Results from the HPLC analyses showed that the recoveries of dextromethorphan using MIP cartridges from human plasma samples in the range of 1-50 ng/mL were higher than 87%.     

Ectoparasites on reintroduced roe deer Capreolus capreolus in Israel

The ectoparasite fauna of reintroduced roe deer (Capreolus capreolus) was surveyed in a Mediterranean forest in Israel. Ectoparasites were collected from four female hand-reared deer during 2004 and 2005. Seasonality, predilection sites of infestation, and the apparent effect of the parasites are presented. This is the first study of roe deer parasites in the East Mediterranean. The ectoparasite fauna included three hippoboscid fly (Lipoptena capreoli, Hippobosca equina, and Hippobosca longipennis), four tick (Rhipicephalus sanguineus, Rhipicephalus turanicus, Rhipicephalus kohlsi, and Hyalomma marginatum), and one unidentified trombiculid mite species. For most of these ectoparasites, this is the first record on roe deer. All ectoparasite species were documented in Israel prior to the reintroduction program; exotic ectoparasites were not detected.     

Multiplicative multi-fractal modeling of electromyography signals for discerning neuropathic conditions

In this paper, we present a new method for multi-scale analysis of electromyography signals based on an interesting fractal process known as multiplicative cascade multi-fractal. Using simulated needle electromyography signals, we show this method provides a means for discrimination of normal and neuropathic electromyography signals. We also present experimental results that show the new parameters, computed using multiplicative cascade multi-fractal modeling, are more robust than the conventional signal parameter, number of turns, in the presence of additive noise. Results of multiplicative cascade multi-fractal modeling are consistent with other multi-scale approaches; advantages and differences are high lighted.     

Epigallocatechin Gallate/Layered Double Hydroxide Nanohybrids: Preparation,Characterization, and In Vitro Anti-Tumor Study

In recent years, nanotechnology in merging with biotechnology has been employed in the area of cancer management to overcome the challenges of chemopreventive strategies in order to gain promising results. Since most biological processes occur in nano scale, nanoparticles can act as carriers of certain drugs or agents to deliver it to specific cells or targets. In this study, we intercalated Epigallocatechin-3-Gallate (EGCG), the most abundant polyphenol in green tea, into Ca/Al-NO₃ Layered double hydroxide (LDH) nanoparticles, and evaluated its efficacy compared to EGCG alone on PC3 cell line. The EGCG loaded LDH nanohybrids were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM) and nanosizer analyses. The anticancer activity of the EGCG-loaded LDH was investigated in prostate cancer cell line (PC3) while the release behavior of EGCG from LDH was observed at pH 7.45 and 4.25. Besides enhancing of apoptotic activity of EGCG, the results showed that intercalation of EGCG into LDH can improve the anti- tumor activity of EGCG over 5-fold dose advantages in in-vitro system. Subsequently, the in-vitro release data showed that EGCG-loaded LDH had longer release duration compared to physical mixture, and the mechanism of diffusion through the particle was rate-limiting step. Acidic attack was responsible for faster release of EGCG molecules from LDH at pH of 4.25 compared to pH of 7.4. The results showed that Ca/Al-LDH nanoparticles could be considered as an effective inorganic host matrix for the delivery of EGCG to PC3 cells with controlled release properties.     

Electrophoretic mobility is a reporter of hairpin structure in single-stranded DNA oligomers

The electrophoretic mobilities of 24 single-stranded DNA oligomers, each containing 26 nucleotide residues, have been measured in polyacrylamide gels and in free solution. The mobilities observed at 20 degrees C differed by approximately 20% in polyacrylamide gels and by approximately 10% in free solution, even though the oligomers contained the same number of bases. Increasing the temperature or adding urea to the solution equalized the mobilities of the oligomers, suggesting that the variable mobilities observed at 20 degrees C are due to the formation of stable secondary structures, most likely hairpins. Thermal melting profiles were measured for eight oligomers in 40 mM Tris acetate buffer. The observed melting temperatures of most oligomers correlated roughly with the mobilities observed at 20 degrees C; however, one oligomer was much more stable than the others. The melting temperatures of four of the oligomers were close to the values predicted by DINAMelt [Markham, N. R., and Zuker, M. (2005) Nucleic Acids Res. 33, W577-W581]; melting temperatures of the other oligomers differed significantly from the predicted values. Thermal melting profiles were also measured for two oligomers as a function of the Tris acetate buffer concentration. The salt concentration dependence of the melting temperatures suggests that 0.15 Tris+ ion per phosphate is released upon denaturation. Because the apparent number of Tris+ ions released is greater than that observed by others for the release of Na+ ions from similar hairpins, the results suggest that DNA hairpins (and, presumably, duplexes) bind more Tris+ ions than Na+ ions in solution.