Prandtl–Tomlinson-Type Models for Coupled Molecular Sliding Friction: Chain-Length Dependence of Friction of Self-assembled Monolayers

Tribology Letters - Most asteroids with a diameter larger than $$\sim 300 \ {\mathrm{m}}$$ are rubble piles, i.e., consisting of more than one solid object. All asteroids are rotating but almost...     

Synthesis and Properties of New Cleavable Cationic Surfactants Containing Carbonate Groups

A novel series of cleavable alkyltrimethylammonium surfactants with different hydrocarbon chain lengths (C8–16) were synthesized. A carbonate break site inserted between the polar head and the hydrocarbon chain makes these compounds hydrolyzable. The reagents used are renewable, (bio)degradable, or reusable. The hydrolysis of these cleavable surfactants will lead to the generation of fatty alcohols and choline, which is an essential biological nutrient. The surface activities in aqueous solution of the synthesized carbonates fulfill the requirement of being good surfactants. In addition, the cleavable compounds containing n-decyl and n-dodecyl chains showed similar or higher antimicrobial activities when compared to a non-cleavable analog.     

Virus-Based Nanoreactors with GALT Activity for Classic Galactosemia Therapy

Enzymatic nanoreactors were obtained by galactose-1-phosphate uridylyl-transferase (GALT) encapsulation into plant virus capsids by a molecular self-assembly strategy. The aim of this work was to produce virus-like nanoparticles containing GALT for an enzyme-replacement therapy for classic galactosemia. The encapsulation efficiency and the catalytic constants of bio-nanoreactors were determined by using different GALT and virus coat protein ratios. The substrate affinity of nanoreactors was slightly lower than that of the free enzyme; the activity rate was 16 % of the GALT free enzyme. The enzymatic nanoreactors without functionalization were internalized into different cell lines including fibroblast and kidney cells, but especially into hepatocytes. The enzymatic nanoreactors are an innovative enzyme preparation with potential use for the treatment of classic galactosemia.     

Interleukin-1β Modulation of the Mechanobiology of Primary Human Pulmonary Fibroblasts: Potential Implications in Lung Repair

Pro-inflammatory cytokines like interleukin-1β (IL-1β) are upregulated during early responses to tissue damage and are expected to transiently compromise the mechanical microenvironment. Fibroblasts are key regulators of tissue mechanics in the lungs and other organs. However, the effects of IL-1β on fibroblast mechanics and functions remain unclear. Here we treated human pulmonary fibroblasts from control donors with IL-1β and used Atomic Force Microscopy to unveil that IL-1β significantly reduces the stiffness of fibroblasts concomitantly with a downregulation of filamentous actin (F-actin) and alpha-smooth muscle (α-SMA). Likewise, COL1A1 mRNA was reduced, whereas that of collagenases MMP1 and MMP2 were upregulated, favoring a reduction of type-I collagen. These mechanobiology changes were functionally associated with reduced proliferation and enhanced migration upon IL-1β stimulation, which could facilitate lung repair by drawing fibroblasts to sites of tissue damage. Our observations reveal that IL-1β may reduce local tissue rigidity by acting both intracellularly and extracellularly through the downregulation of fibroblast contractility and type I collagen deposition, respectively. These IL-1β-dependent mechanical effects may enhance lung repair further by locally increasing pulmonary tissue compliance to preserve normal lung distension and function. Moreover, our results support that IL-1β provides innate anti-fibrotic protection that may be relevant during the early stages of lung repair.     

Nanoconfined (Bio)Catalysts as Efficient Glucose‐Responsive Nanoreactors

Herein, the design, synthesis, and characterization of bifunctional hybrid nanoreactors used for concurrent one‐pot chemoenzymatic reactions are shown. In the design, the enzyme, glucose oxidase, is wrapped with a peroxidase‐mimetic catalytic polymer. Hemin, the organic catalyst, is linked to the flexible polymeric scaffold through coordination to the imidazole groups that hang out the network. This spatial arrangement, which works as a metabolic channel, is optimized for cooperative chemoenzymatic reactions in which the enzyme catalyzes first. A deep characterization of the integrated nanoreactors demonstrates that the confinement of two distinct catalytic sites in the nanospace is very effective in one‐pot reactions. Moreover, besides its role as scaffold material, the polymeric mantel protects both the biocatalyst and the chemical catalyst from degradation and inactivation in the presence of organic solvents. Furthermore, the polymeric environment of the nanoreactors can be tailored in order to trigger the assembly of those into highly active heterogeneous hybrid catalysts. Finally, the new nanoreactors are applied to the efficient degradation of organic aromatic compounds using glucose as the only fuel.     

Special Issue: Technological Advancements in Wireless and Optical Communication Systems

Wireless Personal Communications -     

A dimensional reduction approach to modulate the core ruminal microbiome associated with methane emissions via selective breeding

The rumen is a complex microbial system of substantial importance in terms of greenhouse gas emissions and feed efficiency. This study proposes combining metagenomic and host genomic data for selective breeding of the cow hologenome toward reduced methane emissions. We analyzed nanopore long reads from the rumen metagenome of 437 Holstein cows from 14 commercial herds in 4 northern regions in Spain. After filtering, data were treated as compositional. The large complexity of the rumen microbiota was aggregated, through principal component analysis (PCA), into few principal components (PC) that were used as proxies of the core metagenome. The PCA allowed us to condense the huge and fuzzy taxonomical and functional information from the metagenome into a few PC. Bivariate animal models were applied using these PC and methane production as phenotypes. The variability condensed in these PC is controlled by the cow genome, with heritability estimates for the first PC of ~0.30 at all taxonomic levels, with a large probability (>83%) of the posterior distribution being >0.20 and with the 95% highest posterior density interval (95%HPD) not containing zero. Most genetic correlation estimates between PC1 and methane were large (≥0.70), with most of the posterior distribution (>82%) being >0.50 and with its 95%HPD not containing zero. Enteric methane production was positively associated with relative abundance of eukaryotes (protozoa and fungi) through the first component of the PCA at phylum, class, order, family, and genus. Nanopore long reads allowed the characterization of the core rumen metagenome using whole-metagenome sequencing, and the purposed aggregated variables could be used in animal breeding programs to reduce methane emissions in future generations.     

Expanding the Toolbox of R-Selective Amine Transaminases by Identification and Characterization of New Members

Amine transaminases (ATAs) are used to synthesize enantiomerically pure amines, which are building blocks for pharmaceuticals and agrochemicals. R-selective ATAs belong to the fold type IV PLP-dependent enzymes, and different sequence-, structure- and substrate scope-based features have been identified in the past decade. However, our knowledge is still restricted due to the limited number of characterized (R)-ATAs, with additional bias towards fungal origin. We aimed to expand the toolbox of (R)-ATAs and contribute to the understanding of this enzyme subfamily. We identified and characterized four new (R)-ATAs. The ATA from Exophiala sideris contains a motif characteristic for d -ATAs, which was previously believed to be a disqualifying factor for (R)-ATA activity. The crystal structure of the ATA from Shinella is the first from a Gram-negative bacterium. The ATAs from Pseudonocardia acaciae and Tetrasphaera japonica are the first characterized (R)-ATAs with a shortened/missing N-terminal helix. The active-site charges vary significantly between the new and known ATAs, correlating with their diverging substrate scope.