Experimental and Finite Element Analysis of the Open-Cells Porous Materials Subjected to Compression Mechanical Loading

Progress in Additive Manufacturing (AM) technology enables the fabrication of complex structures that could not be obtained with traditional manufacturing methods. One AM research area is the development and use of lightweight products with cellular structures, containing complex lattices and pores, which give improved performance and functionality. It is well known that there is a strong link between mechanical properties and architecture of samples with cellular structures. This paper presents a comparison and validation of Finite Element Analysis (FEA) simulations of cellular structures with experimental data obtained from compression tests, and degradation behaviour under load compression. The specimens, with spherical open-cells, were produced in VeroClear RGD810 photopolymer resin. Mechanical compression tests were performed to investigate the compressive behaviour and the mechanical response was registered in the form of compressive stress-strain curves. Also, using the specimens’ CAD data and compression test parameters, a Finite Element Analysis (FEA) was performed. A macroscopic analysis of the specimens’ structure and microhardness tests before and after compression tests were also carried out

Chl a fluorescence and proteomics reveal protection of the photosynthetic apparatus to dehydration in tolerant but not in susceptible wheat cultivars

Seedlings of spring wheat (Triticum aestivum L.) cultivars, Ethos and Zebra, differing in drought tolerance were dehydrated to reach a water saturation deficit (WSD) in leaves ~15, 30, and 50 %. Ethos, the drought tolerant cultivar, dried slower in comparison with Zebra and regrew in 70 % upon rehydration. The effect of dehydration on photosystem Seedlings of spring wheat (Triticum aestivum L.) cultivars, Ethos and Zebra, differing in drought tolerance were dehydrated to reach a water saturation deficit (WSD) in leaves ~15, 30, and 50 %. Ethos, the drought tolerant cultivar, dried slower in comparison with Zebra and regrew in 70 % upon rehydration. The effect of dehydration on photosystem II was evaluated by Chl a fluorescence (OJIP transients). The inflection point of double normalized curves (ΔWOJ) calculated for Ethos was negative for seedlings with 15 % WSD, nearly zero for those with 30 % WSD, and about +0.05 for those with 50 % WSD. In case of Zebra, the 15 % WSD already induced a positive ΔWOJ (+0.05) and 50 % WSD maximized it to +0.10, which is a sign of drought susceptibility. The proteomic studies revealed, that among identified 850 spots, 80 protein spots were differentially expressed during dehydration. The differentially expressed proteins of the drought tolerant cultivar indicated the protection of the photosynthetic apparatus and proteome rebuilding in response to drought. In the drought susceptible cultivar, protection of proteins and membranes and partial scavenging reactive oxygen species appeared.Bio-organic Synthesi

Intertwined Precursor Supply during Biosynthesis of the Catecholate-Hydroxamate Siderophores Qinichelins in Streptomyces sp MBT76

Bio-organic SynthesisMicrobial Biotechnolog

Identification of glucose kinase dependent and independent pathways for carbon control of primary metabolism, development and antibiotic production in Streptomyces coelicolor by quantitative proteomics

Bio-organic SynthesisMicrobial Biotechnolog

C-terminal extensions of ku70 and ku80 differentially influence dna end binding properties

The Ku70/80 heterodimer binds to DNA ends and attracts other proteins involved in the non-homologous end-joining (NHEJ) pathway of DNA double-strand break repair. We developed a novel assay to measure DNA binding and release kinetics using differences in Förster resonance

Proteasomal activity-based probes mark protein homeostasis in muscles

Bio-organic Synthesi

Two-step bioorthogonal activity-based protein profiling of individual human proteasome catalytic sites

Bioorthogonal chemistry allows the selective modification of biomolecules in complex biological samples. One application of this methodology is in two-step activity-based protein profiling (ABPP), a methodology that is particularly attractive where direct ABPP using fluorescent or biotinylated probes is ineffective. This paper describes a set of norbornene-modified, mechanism-based proteasome inhibitors aimed to be selective for each of the six catalytic sites of human constitutive proteasomes and immunoproteasomes. The probes designed for β1i, β2i, β5c and β5i proved to be useful two-step ABPs that effectively label their designed proteasome subunits in both Raji cell extracts and living Raji cells through inverse-electron-demand Diels-Alder (IEDDA) ligation. The compound designed for β1c proved incapable of penetrating the cell membrane, but effectively labels β1c  in vitro . The compound designed for β2c proved not selective, but its azide-containing analogue LU-002c proved effective in labeling of β2c via azide-alkyne click ligation chemistry both  in vitro and  in situ . In total, our results contribute to the growing list of proteasome activity tools to include five subunit-selective activity-based proteasome probes, four of which reporting on proteasome activities in living cells.Bio-organic Synthesi

A chemical biological approach to study G protein-coupled receptors: labeling the adenosine A1 receptor using an electrophilic covalent probe

G protein-coupled receptors (GPCRs) have been known for decades as attractive drug targets. This has led to the development and approval of many ligands targeting GPCRs. Although ligand binding effects have been studied thoroughly for many GPCRs, there are multiple aspects of GPCR signaling that remain poorly understood. The reasons for this are the difficulties that are encountered upon studying GPCRs, for example, a poor solubility and low expression levels. In this work, we have managed to overcome some of these issues by developing an affinity-based probe for a prototypic GPCR, the adenosine A1 receptor (A1AR). Here, we show the design, synthesis, and biological evaluation of this probe in various biochemical assays, such as SDS-PAGE, confocal microscopy, and chemical proteomics.Toxicolog

Olaparib based photo-affinity probes for PARP-1 detection in living cells

The poly-ADP-ribose polymerase (PARP) is a protein from the family of ADP-ribosyltransferases that catalyzes poly adenosine diphosphate ribose (ADPR) formation in order to attract the DNA repair machinery to DNA damage sites. Inhibition of PARP activity by olaparib can cause cell death which is of clinical relevance in some tumor types. This demonstrates that quantification of PARP activity in the context of living cells is of great importance. In this work we present the design, synthesis and biological evaluation of photo-activatable affinity probes inspired by the olaparib molecule which are equipped with a diazirine for covalent attachment upon activation by UV light and a ligation handle for the addition of a reporter group of choice. SDS-PAGE, western blotting and label-free LC-MS/MS quantification analysis show that the probes target the PARP-1 protein and are selectively outcompeted by olaparib suggesting binding in the same enzymatic pocket.Bio-organic SynthesisMolecular Physiolog

Identification and isolation of lantibiotics from culture: a bioorthogonal chemistry approach

Bio-organic SynthesisMicrobial Biotechnolog