Yersinia entomophaga Tc toxin is released by T10SS-dependent lysis of specialized cell subpopulations.

Disease-causing bacteria secrete numerous toxins to invade and subjugate their hosts. Unlike many smaller toxins, the secretion machinery of most large toxins remains enigmatic. By combining genomic editing, proteomic profiling and cryo-electron tomography of the insect pathogen Yersinia entomophaga, we demonstrate that a specialized subset of these cells produces a complex toxin cocktail, including the nearly ribosome-sized Tc toxin YenTc, which is subsequently exported by controlled cell lysis using a transcriptionally coupled, pH-dependent type 10 secretion system (T10SS).

Structure of the native myosin filament in the relaxed cardiac sarcomere.

The thick filament is a key component of sarcomeres, the basic units of striated muscle. Alterations in thick filament proteins are associated with familial hypertrophic cardiomyopathy and other heart and muscle diseases. Despite the central importance of the thick filament, its molecular organization remains unclear.

Aurophilic Molecules on Surfaces. Part II. (NapNC)AuCl on Au(111).

Although aurophilicity is a well-known phenomenon in structural gold chemistry and is found in many crystals of Au(I) complexes, its potential for self-assembly in thin films is not yet explored. This paper is Part II of a study, in which we investigated the ultrathin film formation of chlorido(2-naphthyl isonitrile) gold(I) on gold surfaces. Here, we present the data for the growth of (NapNC)AuCl on isotropic Au(111) surfaces.

Aurophilic Molecules on Surfaces. Part I. (NapNC)AuCl on Au(110).

Aurophilicity is a well-known phenomenon in structural gold chemistry and is found in many crystals of Au(I) complexes. However, these attractive dispersion forces between and within complexes containing Au(I) moieties have not been well studied in ultrathin films. In this paper, we elucidate the interaction of chlorido(2-naphthyl isonitrile)gold(I) on and with Au(110) surfaces.

TomoTwin: generalized 3D localization of macromolecules in cryo-electron tomograms with structural data mining.

Cryogenic-electron tomography enables the visualization of cellular environments in extreme detail, however, tools to analyze the full amount of information contained within these densely packed volumes are still needed. Detailed analysis of macromolecules through subtomogram averaging requires particles to first be localized within the tomogram volume, a task complicated by several factors including a low signal to noise ratio and crowding of the cellular space. Available methods for this task suffer either from being error prone or requiring manual annotation of training data.

Accelerated 2D Classification With ISAC Using GPUs.

A widely used approach to analyze single particles in electron microscopy data is 2D classification. This process is very computationally expensive, especially when large data sets are analyzed. In this paper we present GPU ISAC, a newly developed, GPU-accelerated version of the established terative table lignment and lustering (ISAC) algorithm for 2D images and generating class averages.

Attenuation of Photoelectron Emission by a Single Organic Layer.

We report an in situ study of the thin-film growth of cobalt-phthalocyanine on Ag(100) surfaces using photoelectron emission microscopy (PEEM) and the Anderson method. Based on the Fowler-DuBridge theory, we were able to correlate the evolution of the mean electron yield acquired with PEEM for coverages up to two molecular layers of cobalt-phthalocyanine to the global work function changes measured with the Anderson method. For coverages above two monolayers, the transients measured with the Anderson method and those obtained with PEEM show different trends.

Structures from intact myofibrils reveal mechanism of thin filament regulation through nebulin.

In skeletal muscle, nebulin stabilizes and regulates the length of thin filaments, but the underlying mechanism remains nebulous. In this work, we used cryo-electron tomography and subtomogram averaging to reveal structures of native nebulin bound to thin filaments within intact sarcomeres. This in situ reconstruction provided high-resolution details of the interaction between nebulin and actin, demonstrating the stabilizing role of nebulin.

Standard deviation of microscopy images used as indicator for growth stages.

Photoelectron emission microscopy (PEEM) and low energy electron microscopy (LEEM) can easily distinguish between organic molecules adsorbed in crystallites or in the wetting layers as well as the bare metal substrate due to their different electronic properties. Already before (and during) the condensation of such solid phases (2D islands or 3D crystallites), there is a dilute 2D gas phase. Such a 2D gas phase consists of molecules, which are highly mobile and diffuse across the surface.

A trigonal coordination of Au(I) phosphane complexes stabilized by O-H X (X = Cl, Br, I) interactions.

Unlabelled: In this work, we show that intramolecular hydrogen bonding can be used to stabilize tri-coordinated phosphane-gold(I) complexes. Two molecular structures of 2-(diphenylphosphino)benzoic acid (L) coordinated to a gold(I) atom were determined by single-crystal X-ray diffraction. The linear L-Au-Br shows a standard linear coordination and dimerizes via hydrogen bonds of the carboxylic acid.

TranSPHIRE: automated and feedback-optimized on-the-fly processing for cryo-EM.

Single particle cryo-EM requires full automation to allow high-throughput structure determination. Although software packages exist where parts of the cryo-EM pipeline are automated, a complete solution that offers reliable on-the-fly processing, resulting in high-resolution structures, does not exist. Here we present TranSPHIRE: A software package for fully-automated processing of cryo-EM datasets during data acquisition.

Recombination mechanisms of luminescence type gas sensors.

Luminescence type gas sensors based on organic luminophores are characterized by an excellent signal stability over the luminophores' lifetime. Even though the sensing material is prone to degradation due to photobleaching, evaluation of the dynamic optical response allows to minimize aging induced drift effects of the luminophore and the optoelectronic components. The gas dependent luminophore decay time is mostly independent of the excitation intensity, which is attributed to the monomolecular recombination in many organic luminophores.

Two particle-picking procedures for filamentous proteins: SPHIRE-crYOLO filament mode and SPHIRE-STRIPER.

Structure determination of filamentous molecular complexes involves the selection of filaments from cryo-EM micrographs. The automatic selection of helical specimens is particularly difficult, and thus many challenging samples with issues such as contamination or aggregation are still manually picked. Here, two approaches for selecting filamentous complexes are presented: one uses a trained deep neural network to identify the filaments and is integrated in SPHIRE-crYOLO, while the other, called SPHIRE-STRIPER, is based on a classical line-detection approach.

The evolution of SPHIRE-crYOLO particle picking and its application in automated cryo-EM processing workflows.

Particle selection is a crucial step when processing electron cryo microscopy data. Several automated particle picking procedures were developed in the past but most struggle with non-ideal data sets. In our recent Communications Biology article, we presented crYOLO, a deep learning based particle picking program.

Proton Conduction in a Single Crystal of a Phosphonato-Sulfonate-Based Coordination Polymer: Mechanistic Insight.

The proton conduction properties of a phosphonato-sulfonate-based coordination polymer are studied by impedance spectroscopy using a single crystal specimen. Two distinct conduction mechanisms are identified. Water-mediated conductance along the crystal surface occurs by mass transport, as evidenced by a high activation energy (0.

Cellulose Nanocrystal-Templated Tin Dioxide Thin Films for Gas Sensing.

Porous tin dioxide is an important low-cost semiconductor applied in electronics, gas sensors, and biosensors. Here, we present a versatile template-assisted synthesis of nanostructured tin dioxide thin films using cellulose nanocrystals (CNCs). We demonstrate that the structural features of CNC-templated tin dioxide films strongly depend on the precursor composition.

Aggregation of Au(i)-complexes on amorphous substrates governed by aurophilicity.

In single crystals of 2-naphthylisonitrile-gold(i)-halide (halide = Cl, Br, I) complexes, AuAu distances are found to be significantly shorter than twice the van der Waals radius, indicating attractive interactions between gold atoms in adjacent molecules. In the particular case of the studied 2-naphthylisonitrile-gold(i) complexes, homodimers are the common structural motifs, in which the linearly coordinated gold exhibits a crossed swords arrangement with the Au atoms of two molecules being at the intersection point. The crossed swords motif is preserved upon physical vapour deposition of both the chlorine and bromine derivatives on amorphous substrates like glass and glassy carbon.

Evaluation of a TEM based Approach for Size Measurement of Particulate (Nano)materials.

An approach for the size measurement of particulate (nano)materials by transmission electron microscopy was evaluated. The approach combines standard operating procedures for specimen preparation, imaging, and image analysis, and it was evaluated on a series of certified reference materials and representative test materials with varying physical properties, including particle size, shape, and agglomeration state. The measurement of the median value of the minimal external particle diameter distribution was intra-laboratory validated.

SPHIRE-crYOLO is a fast and accurate fully automated particle picker for cryo-EM.

Selecting particles from digital micrographs is an essential step in single-particle electron cryomicroscopy (cryo-EM). As manual selection of complete datasets-typically comprising thousands of particles-is a tedious and time-consuming process, numerous automatic particle pickers have been developed. However, non-ideal datasets pose a challenge to particle picking.

Determination of the refractive indices of ionic liquids by ellipsometry, and their application as immersion liquids.

In principle, ionic liquids (ILs) can serve as stable and less harmful high-refractive-index liquids (n>1.60). However, detailed information on their complex refractive indices and dispersions is rare.

Molecular Reorientation during the Initial Growth of Perfluoropentacene on Ag(110).

Perfluoropentacene (PFP) is an organic material that has been widely studied over the last years and has already found applications in organic electronics. However, fundamental physical questions, such as the structural formation and the preferential orientation of the molecules during deposition on metal surfaces, are still not fully understood. In this work, we report on a unique in-plane molecular reorientation during the completion of the first monolayer of PFP on the Ag(110) surface.

Structural transitions of F-actin upon ATP hydrolysis at near-atomic resolution revealed by cryo-EM.

The function of actin is coupled to the nucleotide bound to its active site. ATP hydrolysis is activated during polymerization; a delay between hydrolysis and inorganic phosphate (P) release results in a gradient of ATP, ADP-P and ADP along actin filaments (F-actin). Actin-binding proteins can recognize F-actin's nucleotide state, using it as a local 'age' tag.

Tungsten Oxide Photonic Crystals as Optical Transducer for Gas Sensing.

Some metal oxide semiconductors, such as tungsten trioxide or tin dioxide, are well-known as resistive transducers for gas sensing and offer high sensitivities down to the part per billion level. Electrical signal read-out, however, limits the information obtained on the electronic properties of metal oxides to a certain frequency range and its application because of the required electrical contacts. Therefore, a novel approach for building an optical transducer for gas reactions utilizing metal oxide photonic crystals is presented here.

Kinetics of ozone decomposition in porous InO monoliths.

The performance of many chemical gas-phase reactions is strongly influenced by the interaction of reactants with interfaces. Nanoporous materials, which exhibit pore diameters up to 100 nm and high specific surface areas, can be utilized to reduce the amount of cost-intensive materials (e.g.