Cell Fractionation.

Protein function is generally dependent on its subcellular localization. In gram-negative bacteria such as Escherichia coli, a protein can be targeted to five different compartments: the cytoplasm, the inner membrane, the periplasm, the outer membrane, and the extracellular medium. Different approaches can be used to determine the protein localization within cell such as in silico identification of protein signal sequences and motifs, electron microscopy and immunogold labeling, optical fluorescence microscopy, and biochemical technics.

SkyPole-A method for locating the north celestial pole from skylight polarization patterns.

True north can be determined on Earth by three means: magnetic compasses, stars, and via the global navigation satellite systems (GNSS), each of which has its own drawbacks. GNSS are sensitive to jamming and spoofing, magnetic compasses are vulnerable to magnetic interferences, and the stars can be used only at night with a clear sky. As an alternative to these methods, nature-inspired navigational cues are of particular interest.

Direct interaction between fd phage pilot protein pIII and the TolQ-TolR proton-dependent motor provides new insights into the import of filamentous phages.

Filamentous phages are one of the simplest examples of viruses with a protein capsid that protects a circular single-stranded DNA genome. The infection is very specific, nonlytic, and can strongly affect the physiology or provide new pathogenic factors to its bacterial host. The infection process is proposed to rely on a pore-forming mechanism similar to that of certain nonenveloped eukaryotic viruses.

Design of infrared optical absorber using silver nanorings array made by a top-down process.

This paper presents the numerical simulation and fabrication of a metasurface composed of silver nanorings with a split-ring gap. These nanostructures can exhibit optically-induced magnetic responses with unique possibilities to control absorption at optical frequencies. The absorption coefficient of the silver nanoring was optimized by performing a parametric study with Finite Difference Time Domain (FDTD) simulations.

The Tol-Pal system of Escherichia coli plays an unexpected role in the import of the oxyanions chromate and phosphate.

Chromate is a toxic metal that enters bacteria by using oxyanion importers. Here, we show that each mutant of the Tol-Pal system of Escherichia coli exhibited increased chromate resistance. This system, which spans the cell envelope, plays a major role in envelope integrity and septation.

Improving Orientation, Packing Density, and Molecular Arrangement in Self-Assembled Monolayers of Bianchoring Ferrocene-Triazole Derivatives by "Click" Chemistry.

This work describes the self-assembled monolayers (SAMs) of two ferrocene derivatives with two anchoring groups (at the bottom and at the top of the SAM) deposited on ultraflat template-stripped gold substrates by cyclic voltammetry and analyzed by complementary surface characterization techniques. The SAM of each molecule is deposited by three different protocols: direct deposition (one step), click reaction on the surface (two steps), and reverse click reaction on the surface (two steps). The SAM structure is well studied to determine the SAM orientation, SAM arrangement, and ferrocene position within the SAM.

Timing of TolA and TolQ Recruitment at the Septum Depends on the Functionality of the Tol-Pal System.

Efficient cell division of Gram-negative bacteria requires the presence of the Tol-Pal system to coordinate outer membrane (OM) invagination with inner membrane invagination (IM) and peptidoglycan (PG) remodeling. The Tol-Pal system is a trans-envelope complex that connects the three layers of the cell envelope through an energy-dependent process. It is composed of the three IM proteins, TolA, TolQ and TolR, the periplasmic protein TolB and the OM lipoprotein Pal.

Direct Observations of the Structural Properties of Semiconducting Polymer: Fullerene Blends under Tensile Stretching.

We describe the impact of tensile strains on the structural properties of thin films composed of PffBT4T-2OD π-conjugated polymer and PCBM fullerenes coated on a stretchable substrate, based on a novel approach using in situ studies of flexible organic thin films. In situ grazing incidence X-ray diffraction (GIXD) measurements were carried out to probe the ordering of polymers and to measure the strain of the polymer chains under uniaxial tensile tests. A maximum 10% tensile stretching was applied (i.

Interplay between Orientation at Electrodes and Copper Activation of Laccase for O Reduction.

Multicopper oxidases (MCOs) catalyze the oxidation of a variety of substrates while reducing oxygen into water through four copper atoms. As an additional feature, some MCOs display an enhanced activity in solution in the presence of Cu. This is the case of the hyperthermophilic laccase HB27 from , the physiologic role of which is unknown.

Decoupling Filamentous Phage Uptake and Energy of the TolQRA Motor in Escherichia coli.

Filamentous phages are nonlytic viruses that specifically infect bacteria, establishing a persistent association with their host. The phage particle has no machinery for generating energy and parasitizes its host's existing structures in order to cross the bacterial envelope and deliver its genetic material. The import of filamentous phages across the bacterial periplasmic space requires some of the components of a macrocomplex of the envelope known as the Tol system.

Challenges and Opportunities in the Design of Liver-on-Chip Microdevices.

The liver is the central hub of xenobiotic metabolism and consequently the organ most prone to cosmetic- and drug-induced toxicity. Failure to detect liver toxicity or to assess compound clearance during product development is a major cause of postmarketing product withdrawal, with disastrous clinical and financial consequences. While small animals are still the preferred model in drug development, the recent ban on animal use in the European Union created a pressing need to develop precise and efficient tools to detect human liver toxicity during cosmetic development.

Tol Energy-Driven Localization of Pal and Anchoring to the Peptidoglycan Promote Outer-Membrane Constriction.

During cell division, gram-negative bacteria must coordinate inner-membrane invagination, peptidoglycan synthesis and cleavage and outer-membrane (OM) constriction. The OM constriction remains largely enigmatic, and the nature of this process, passive or active, is under debate. The proton-motive force-dependent Tol-Pal system performs a network of interactions within these three compartments.

Similarities and Differences between Colicin and Filamentous Phage Uptake by Bacterial Cells.

Gram-negative bacteria have evolved a complex envelope to adapt and survive in a broad range of ecological niches. This physical barrier is the first line of defense against noxious compounds and viral particles called bacteriophages. Colicins are a family of bactericidal proteins produced by and toxic to and closely related bacteria.

Plasmonic Nanocomposites Based on Silver Nanocube-Polymer Blends Displaying Nearly Perfect Absorption in the UV Region.

Plasmonic nanocomposites based on well-dispersed silver nanocubes in poly(vinylpyrrolidone) are presented that are solution-processed into layers of varying volume fractions of nanocubes. We show that the high-energy modes of the nanocubes are almost insensitive to plasmonic coupling within the nanocube assemblies, leading to a linear increase in light absorption in the UV region with the nanocube densities. Concerning the main dipolar resonance mode at 450 nm, it is strongly affected by the formation of these assemblies, leading to an increased absorption in the UV region as well as a large absorption band in the visible region.

Early skeletal colonization of the coral holobiont by the microboring Ulvophyceae Ostreobium sp.

Ostreobium sp. (Bryopsidales, Ulvophyceae) is a major microboring alga involved in tropical reef dissolution, with a proposed symbiotic lifestyle in living corals. However, its diversity and colonization dynamics in host's early life stages remained unknown.

Cell Fractionation.

Protein function is generally dependent on its subcellular localisation. In Gram-negative bacteria such as Escherichia coli, a protein can be targeted to five different compartments: the cytoplasm, the inner membrane, the periplasm, the outer membrane and the extracellular medium. Different approaches can be used to determine the protein localisation within a cell such as in silico identification of protein signal sequences and motifs, electron microscopy and immunogold labelling, optical fluorescence microscopy, and biochemical technics.

Electrostatic interactions between the CTX phage minor coat protein and the bacterial host receptor TolA drive the pathogenic conversion of .

is a natural inhabitant of aquatic environments and converts to a pathogen upon infection by a filamentous phage, CTXΦ, that transmits the cholera toxin-encoding genes. This toxigenic conversion of has evident implication in both genome plasticity and epidemic risk, but the early stages of the infection have not been thoroughly studied. CTXΦ transit across the bacterial periplasm requires binding between the minor coat protein named pIII and a bacterial inner-membrane receptor, TolA, which is part of the conserved Tol-Pal molecular motor.

Optical modeling and optimizations of CuZnSnSe solar cells using the modified transfer matrix method.

The fast and computationally inexpensive Modified Transfer Matrix Method (MTM) is employed to simulate the optical response of kesterite CuZnSnSe solar cells. This method can partially take into account the scattering effects due to roughness at the interfaces between the layers of the stack. We analyzed the optical behavior of the whole cell structure by varying the thickness of the TCO layer (iZnO + ITO) between 50 and 1200 nm and the buffer CdS layer between 0 and 100 nm.

Xenobiotic metabolizing enzymes in human skin and SkinEthic reconstructed human skin models.

Skin metabolism is becoming a major consideration in the development of new cosmetic ingredients, skin being the first organ exposed to them. In order to replace limited samples of Excised human skin (EHS), in vitro engineered human skins have been developed. 3D models are daily used to develop and evaluate new cosmetic ingredients and have to be characterized and compared with EHS in terms of metabolic capabilities.

Use of read-across and computer-based predictive analysis for the safety assessment of PEG cocamines.

In the European Union animal testing has been eliminated for cosmetic ingredients while the US Cosmetic Ingredient Review Expert Panel may request data from animal studies. The use of read-across and predictive toxicology provides a path for filling data gaps without additional animal testing. The PEG cocamines are tertiary amines with an alkyl group derived from coconut fatty acids and two PEG chains of varying length.

Comparison of xenobiotic metabolizing enzyme activities in ex vivo human skin and reconstructed human skin models from SkinEthic.

Skin function is not limited to a physical barrier. According to its total surface area, it is also considered as an extra-hepatic metabolizing organ. In vitro engineered human skins have been developed to replace limited ex vivo normal human skin samples (NHS).

Building shared experience to advance practical application of pathway-based toxicology: liver toxicity mode-of-action.

A workshop sponsored by the Human Toxicology Project Consortium (HTPC), "Building Shared Experience to Advance Practical Application of Pathway-Based Toxicology: Liver Toxicity Mode-of-Action" brought together experts from a wide range of perspectives to inform the process of pathway development and to advance two prototype pathways initially developed by the European Commission Joint Research Center (JRC): liver-specific fibrosis and steatosis. The first half of the workshop focused on the theory and practice of pathway development; the second on liver disease and the two prototype pathways. Participants agreed pathway development is extremely useful for organizing information and found that focusing the theoretical discussion on a specific AOP is extremely helpful.

Use of human in vitro skin models for accurate and ethical risk assessment: metabolic considerations.

Several human skin models employing primary cells and immortalized cell lines used as monocultures or combined to produce reconstituted 3D skin constructs have been developed. Furthermore, these models have been included in European genotoxicity and sensitization/irritation assay validation projects. In order to help interpret data, Cosmetics Europe (formerly COLIPA) facilitated research projects that measured a variety of defined phase I and II enzyme activities and created a complete proteomic profile of xenobiotic metabolizing enzymes (XMEs) in native human skin and compared them with data obtained from a number of in vitro models of human skin.

Colicin M, a peptidoglycan lipid-II-degrading enzyme: potential use for antibacterial means?

Colicins are proteins produced by some strains of Escherichia coli to kill competitors belonging to the same species. Among them, ColM (colicin M) is the only one that blocks the biosynthesis of peptidoglycan, a specific bacterial cell-wall polymer essential for cell integrity. ColM acts in the periplasm by hydrolysing the phosphoester bond of the peptidoglycan lipid intermediate (lipid II).