Photosynthetic Reaction-Center/Graphene Biohybrid for Optoelectronics.

Photosynthetic reaction center proteins (RC) purified from purple bacterial strains were deposited on graphene layer prepared by liquid phase exfoliation and light-induced resistance change was measured. By measuring the temperature dependence of the resistance change of the bare and RC covered graphene and comparing with the one inactivated by protein unfolding, two effects were possible to separate. One of them is the resistance change due to temperature effect.

De-adhesion dynamics of melanoma cells from brain endothelial layer.

Metastasis formation is a complex and not entirely understood process. The poorest prognosis and the most feared complications are associated to brain metastases. Melanoma derived brain metastases show the highest prevalence.

Expression of pattern recognition receptors and activation of the non-canonical inflammasome pathway in brain pericytes.

Cerebral pericytes are mural cells embedded in the basement membrane of capillaries. Increasing evidence suggests that they play important role in controlling neurovascular functions, i.e.

Direct mapping of melanoma cell - endothelial cell interactions.

The most life-threatening aspect of cancer is metastasis; cancer patient mortality is mainly due to metastasis. Among all metastases, presence of brain metastasis is one with the poorest prognosis; the median survival time can be counted in months. Therefore, prevention or decreasing their incidence would be highly desired both by patients and physicians.

Antimicrobial nodule-specific cysteine-rich peptides disturb the integrity of bacterial outer and inner membranes and cause loss of membrane potential.

Background: Certain legume plants produce a plethora of AMP-like peptides in their symbiotic cells. The cationic subgroup of the nodule-specific cysteine-rich (NCR) peptides has potent antimicrobial activity against gram-negative and gram-positive bacteria as well as unicellular and filamentous fungi.

Findings: It was shown by scanning and atomic force microscopies that the cationic peptides NCR335, NCR247 and Polymyxin B (PMB) affect differentially on the surfaces of Sinorhizobium meliloti bacteria.

Elasto-mechanical properties of living cells.

The possibility to directly measure the elasticity of living cell has emerged only in the last few decades. In the present study the elastic properties of two cell lines were followed. Both types are widely used as cell barrier models (e.

Transmigration characteristics of breast cancer and melanoma cells through the brain endothelium: Role of Rac and PI3K.

Brain metastases are common and devastating complications of both breast cancer and melanoma. Although mammary carcinoma brain metastases are more frequent than those originating from melanoma, this latter has the highest tropism to the brain. Using static and dynamic in vitro approaches, here we show that melanoma cells have increased adhesion to the brain endothelium in comparison to breast cancer cells.

Interaction of cysteine-rich cationic antimicrobial peptides with intact bacteria and model membranes.

Antimicrobial peptides are small proteins that exhibit a broad spectrum of antimicrobial activity. Their chemical structure allows them to interact (attach and insert) with membranes. The fine details about this interaction and their mode of action are not fully clarified yet.

Addressing the optimal silver content in bioactive glass systems in terms of BSA adsorption.

Bioactive glasses doped with silver are aimed to minimize the risk of microbial contamination; therefore, the influence of silver on the bioactive properties is intensely investigated. However, information related to the role played by silver, when added to the bioactive glass composition, on biocompatibility properties is scarce. This aspect is essential as long as the silver content can influence blood protein adsorption onto the surface of the glass, thus affecting the material's biocompatibility.

DAAM is required for thin filament formation and Sarcomerogenesis during muscle development in Drosophila.

During muscle development, myosin and actin containing filaments assemble into the highly organized sarcomeric structure critical for muscle function. Although sarcomerogenesis clearly involves the de novo formation of actin filaments, this process remained poorly understood. Here we show that mouse and Drosophila members of the DAAM formin family are sarcomere-associated actin assembly factors enriched at the Z-disc and M-band.

Role of Rho/ROCK signaling in the interaction of melanoma cells with the blood-brain barrier.

We have investigated the role of the Rho/ROCK signaling pathway in the interaction of metastatic melanoma cells with the brain endothelium. ROCK inhibition induced a shift of melanoma cells to the mesenchymal phenotype, increased the number of melanoma cells attached to the brain endothelium, and strengthened the adhesion force between melanoma and endothelial cells. Inhibition of ROCK raised the number of melanoma cells migrating through the brain endothelial monolayer and promoted the formation of parenchymal brain metastases in vivo.

Double-stranded RNA attenuates the barrier function of human pulmonary artery endothelial cells.

Circulating RNA may result from excessive cell damage or acute viral infection and can interact with vascular endothelial cells. Despite the obvious clinical implications associated with the presence of circulating RNA, its pathological effects on endothelial cells and the governing molecular mechanisms are still not fully elucidated. We analyzed the effects of double stranded RNA on primary human pulmonary artery endothelial cells (hPAECs).

Photosynthetic reaction centers/ITO hybrid nanostructure.

Photosynthetic reaction center proteins purified from Rhodobacter sphaeroides purple bacterium were deposited on the surface of indium tin oxide (ITO), a transparent conductive oxide, and the photochemical/-physical properties of the composite were investigated. The kinetics of the light induced absorption change indicated that the RC was active in the composite and there was an interaction between the protein cofactors and the ITO. The electrochromic response of the bacteriopheophytine absorption at 771 nm showed an increased electric field perturbation around this chromophore on the surface of ITO compared to the one measured in solution.

κ-Casein terminates casein micelle build-up by its "soft" secondary structure.

In our previous paper (Nagy et al. in J Biol Chem 285:38811-38817, 2010) by using a multilayered model system, we showed that, from α-casein, aggregates (similar to natural casein micelles) can be built up step by step if Ca-phosphate nanocluster incorporation is ensured between the protein adsorption steps. It remained, however, an open question whether the growth of the aggregates can be terminated, similarly to in nature with casein micelles.

Melanoma cell-derived exosomes alter macrophage and dendritic cell functions in vitro.

To clarify controversies in the literature of the field, we have purified and characterized B16F1 melanoma cell derived exosomes (mcd-exosomes) then we attempted to dissect their immunological activities. We tested how mcd-exosomes influence CD4+ T cell proliferation induced by bone marrow derived dendritic cells; we quantified NF-κB activation in mature macrophages stimulated with mcd-exosomes, and we compared the cytokine profile of LPS-stimulated, IL-4 induced, and mcd-exosome treated macrophages. We observed that mcd-exosomes helped the maturation of dendritic cells, enhancing T cell proliferation induced by the treated dendritic cells.

Evidence of multipolar response of Bacteriorhodopsin by noncollinear second harmonic generation.

Noncollinear second harmonic generation from a Bacteriorhodopsin (BR) oriented multilayer film was systematically investigated by varying the polarization state of both fundamental beams. Both experimental results and theoretical simulations, show that the resulting polarization mapping is an useful tool to put in evidence the optical chirality of the investigated film as well as the corresponding multipolar contributions to the nonlinear.

Adhesion and stress relaxation forces between melanoma and cerebral endothelial cells.

Mechanical parameters play a crucial role in proper cellular functions. This article examines the process of the appearance and breaking of adhesion forces during contact between the confluent cerebral endothelial cell layer and a melanoma cell attached to a tipless cantilever. This adhesion is the initial phase of melanoma transmigration through the endothelial cell layer.

Effect of antimicrobial peptide-amide: indolicidin on biological membranes.

Indolicidin, a cationic antimicrobial tridecapeptide amide, is rich in proline and tryptophan residues. Its biological activity is intensively studied, but the details how indolicidin interacts with membranes are not fully understood yet. We report here an in situ atomic force microscopic study describing the effect of indolicidin on an artificial supported planar bilayer membrane of dipalmitoyl phosphatidylcholine (DPPC) and on purple membrane of Halobacterium salinarum.

Spatial and temporal dependence of the cerebral endothelial cells elasticity.

The reliable determination of the mechanical properties of a living cell is one of the most important challenges of the atomic force microscopic measurements. In the present study the spatial and temporal dependency of the force measurements on cerebral endothelial cells was investigated. Besides imaging the cells, two different sequences of force measurements were applied: Acquisition of force curves in short time at several points across the cell surface investigating spatial dependence of the elasticity.

Atypical transcriptional regulation and role of a new toxin-antitoxin-like module and its effect on the lipid composition of Bradyrhizobium japonicum.

A toxin-antitoxin (TA)-like system (designated as bat/bto genes) was identified in Bradyrhizobium japonicum, based on sequence homology and similarities in organization and size to known TA systems. Deletion of the bat/bto module resulted in pleiotropic alterations in cell morphology and metabolism. The generation time of the mutant was considerably decreased in rich media.

Terahertz radiation from bacteriorhodopsin reveals correlated primary electron and proton transfer processes.

The kinetics of electrogenic events associated with the different steps of the light-induced proton pump of bacteriorhodopsin is well studied in a wide range of time scales by direct electric methods. However, the investigation of the fundamental primary charge translocation phenomena taking place in the functional energy conversion process of this protein, and in other biomolecular assemblies using light energy, has remained experimentally unfeasible because of the lack of proper detection technique operating in the 0.1- to 20-THz region.

Monolithically integrated bacteriorhodopsin-GaAs field-effect transistor photoreceiver.

We have applied the large photovoltage developed across a layer of selectively deposited bacteriorhodopsin to the gate terminal of a monolithically integrated GaAs-based modulation-doped field-effect transistor, which delivers an amplified photoinduced current signal. The integrated biophotoreceiver device exhibits a responsivity of 3.8 A/W.

Regulation of cerebral endothelial cell morphology by extracellular calcium.

Cerebral endothelial cells interconnected by tight and adherens junctions constitute the structural basis of the blood-brain barrier. Extracellular calcium ions have been reported to play an important role in the formation and maintenance of the junctional complex. However, little is known about the action of calcium depletion on the structural characteristics of cerebral endothelial cells.

Direct observation of protein motion during the photochemical reaction cycle of bacteriorhodopsin.

Platinum-coated, conductive atomic force microscope cantilevers were used to deposit electrophoretically purple membranes from Halobacterium salinarum on the bottom part of the cantilevers. By illuminating the bacteriorhodopsin-containing purple membranes, the protein goes through its photochemical reaction cycle, during which a conformational change happens in the protein, changing its shape and size. The size change of the protein acts upon the cantilever by causing its deflection, which can be monitored by the detection system of the atomic force microscope.

Low-power bacteriorhodopsin-silicon n-channel metal-oxide field-effect transistor photoreceiver.

A bacteriorhodopsin (bR)-silicon n-channel metal-oxide field-effect transistor (NMOSFET) monolithically integrated photoreceiver is demonstrated. The bR film is selectively formed on an external gate electrode of the transistor by electrophoretic deposition. A modified biasing circuit is incorporated, which helps to match the resistance of the bR film to the input impedance of the NMOSFET and to shift the operating point of the transistor to coincide with the maximum gain.