Confocal Raman microscopy, a non-invasive, label free and high spatial resolution imaging technique is used to study apoptosis in living MCF-7 cells. The images are obtained based on the Raman spectra of cells components and drug and are treated by K-mean cluster analysis method to localize drug in cell. Distribution of paclitaxel in cells is verified by calculating the correlation coefficient between the reference spectrum of the paclitaxel and the Raman spectra of the whole image. Our results show that the drug is distributed all over in the cytoplasm, that is in good agreement with other recent researches suggesting a new picture of the pharmaceutical action of this drug based on rapid binding of crystallized paclitaxel to free tubulin. Finally cell apoptosis is monitored by tracing cytochrome c apparition and distribution in cytoplasm.

A prior peripheral nerve injury in vivo, promotes a rapid elongated mode of sensory neurons neurite regrowth in vitro. This in vitro model of conditioned axotomy allows analysis of the cellular and molecular mechanisms leading to an improved neurite re-growth. Our differential interference contrast microscopy and immunocytochemistry results show that conditioned axotomy, induced by sciatic nerve injury, did not increase somatic size of adult lumbar sensory neurons from mice dorsal root ganglia sensory neurons but promoted the appearance of larger neurites and growth cones. Using atomic force microscopy on live neurons, we investigated whether membrane mechanical properties of growth cones of axotomized neurons were modified following sciatic nerve injury. Our data revealed that neurons having a regenerative growth were characterized by softer growth cones, compared to control neurons. The increase of the growth cone membrane elasticity suggests a modification in the ratio and the inner framework of the main structural proteins.

A measurable magnetic (nonlocal) contribution to the second harmonic generation (SHG) of nonmagnetic materi- als is an intriguing issue related to chiral materials, such as biomolecules. Here we report the detection of an intensity-dependent optically induced magnetization of a chiral bacteriorhodopsin film under femtosecond pulse excitation (830 nm) and far from the material's resonance. The analysis of the pump intensity-dependent noncol- linear SHG signal, by means of the polarization map of normalized Stokes parameters, allows one to improve the detection of the nonlinear optical magnetization M 2ω contribution to the SHG signal.

Background: A combinatorial phage display approach was previously used to evolve a 12-mer peptide (SVSVGMKP- SPRP) with the highest affinity for different semiconductor surfaces.Thediscoveryofthemultipleoccurrencesofthe SVSVGMKPSPRP sequence in an all-against-all basic local alignment search tool search of PepBank sequences was unexpected, and a Google search using the peptide sequence recovered 58 results concerning 12 patents and 16 scientific publications. The number of patent and articles indicates that the peptide is perhaps a broad range adhesion peptide. Methods: To evaluate peptide properties, we conducted a study to investigate peptide adhesion on different inor- ganic substrates by mass spectrometry and atomic force microscopy for gold, carbon nanotubes, cobalt, chrome alloy, titanium, and titanium alloy substrates. Results: Our results showed that the peptide has a great potential as a linker to functionalize metallic surfaces if specificity is not a key factor. This peptide is not specific to a particular metal surface, but it is a good linker for the functionalization of a wide range of metallic materials. Conclusion: The fact that this peptide has the potential to adsorb on a large set of inorganic surfaces suggests novel promising directions for further investigation. Affinity determination of SVSVGMKPSPRP peptide would be an important issue for eventual commercial uses.

A recombinant hepatitis B surface antigen (HBsAg) has been produced in the yeast Saccharomyces cere- visiae and used as a vaccine against hepatitis B virus (HBV) infection. The present study aimed to optimize the extraction of recombinant virus-like particles (rVLPs) to develop a simple purification procedure based on gel filtration and high performance size-exclusion chromatography. The findings showed that disruption of yeast cells with alumina powder increased the yield of the total proteins (290 mg/l) and rVLPs (1 mg/l) compared to the values for glass beads (171 mg/l and 0.5 mg/l), as estimated by quantita- tive ELISA. The purification of rVLPs was performed by two consecutive gel filtration chromatographic steps, namely Sephacryl S-200 followed by SEC-250 HPLC. The purified M protein was analyzed by atomic force microscopy and shown to assemble in particles that were able to recognize HBV antibodies in the sera of patients with chronic hepatitis B, providing evidence for their immunoreactivity.