Exploring the influence of H-bonding and ligand constraints on thiolate ligated non-heme iron mediated dioxygen activation.

Converting triplet dioxygen into a powerful oxidant is fundamentally important to life. The study reported herein quantitatively examines the formation of a well-characterized, reactive, O-derived thiolate ligated Fe-superoxo using low-temperature stopped-flow kinetics. Comparison of the kinetic barriers to the formation of this species two routes, involving either the addition of (a) O to [Fe(S N(Pr,Pr))] (1) or (b) superoxide to [Fe(S N(Pr,Pr))] (3) is shown to provide insight into the mechanism of O activation.

Recognition of yeast β-glucan particles triggers immunometabolic signaling required for trained immunity.

Fungal β-glucans are major drivers of trained immunity which increases long-term protection against secondary infections. Heterogeneity in β-glucan source, structure, and solubility alters interaction with the phagocytic receptor Dectin-1 and could impact strategies to improve trained immunity in humans. Using a panel of diverse β-glucans, we describe the ability of a specific yeast-derived whole-glucan particle (WGP) to reprogram metabolism and thereby drive trained immunity in human monocyte-derived macrophages and mice bone marrow .

ENDOR Spectroscopy Reveals the "Free" 5'-Deoxyadenosyl Radical in a Radical SAM Enzyme Active Site Actually is Chaperoned by Close Interaction with the Methionine-Bound [4Fe-4S] Cluster.

H and C hyperfine coupling constants to 5'-deoxyadenosyl (5'-dAdo•) radical trapped within the active site of the radical -adenosyl-l-methionine (SAM) enzyme, pyruvate formate lyase-activating enzyme (PFL-AE), both in the absence of substrate and the presence of a reactive peptide-model of the PFL substrate, are completely characteristic of a classical organic free radical whose unpaired electron is localized in the 2pπ orbital of the sp C5'-carbon ( 12139-12146). However, prior electron-nuclear double resonance (ENDOR) measurements had indicated that this 5'-dAdo• free radical is never truly "free": tight van der Waals contact with its target partners and active-site residues guide it in carrying out the exquisitely precise, regioselective reactions that are hallmarks of RS enzymes. Here, our understanding of how the active site chaperones 5'-dAdo• is extended through the finding that this apparently unexceptional organic free radical has an anomalous g-tensor and exhibits significant Fe, C, N, and H hyperfine couplings to the adjacent, isotopically labeled, methionine-bound [4Fe-4S] cluster cogenerated with 5'-dAdo• during homolytic cleavage of cluster-bound SAM.

Pyruvate formate-lyase activating enzyme: The catalytically active 5'-deoxyadenosyl radical caught in the act of H-atom abstraction.

Enzymes of the radical -adenosyl-l-methionine (radical SAM, RS) superfamily, the largest in nature, catalyze remarkably diverse reactions initiated by H-atom abstraction. Glycyl radical enzyme activating enzymes (GRE-AEs) are a growing class of RS enzymes that generate the catalytically essential glycyl radical of GREs, which in turn catalyze essential reactions in anaerobic metabolism. Here, we probe the reaction of the GRE-AE pyruvate formate-lyase activating enzyme (PFL-AE) with the peptide substrate RVSGYAV, which mimics the site of glycyl radical formation on the native substrate, pyruvate formate-lyase.

Computational engineering of previously crystallized pyruvate formate-lyase activating enzyme reveals insights into SAM binding and reductive cleavage.

Radical S-adenosyl-l-methionine (SAM) enzymes are ubiquitous in nature and carry out a broad variety of difficult chemical transformations initiated by hydrogen atom abstraction. Although numerous radical SAM (RS) enzymes have been structurally characterized, many prove recalcitrant to crystallization needed for atomic-level structure determination using X-ray crystallography, and even those that have been crystallized for an initial study can be difficult to recrystallize for further structural work. We present here a method for computationally engineering previously observed crystallographic contacts and employ it to obtain more reproducible crystallization of the RS enzyme pyruvate formate-lyase activating enzyme (PFL-AE).

Macrophage innate training induced by IL-4 and IL-13 activation enhances OXPHOS driven anti-mycobacterial responses.

Macrophages are a highly adaptive population of innate immune cells. Polarization with IFNγ and LPS into the 'classically activated' M1 macrophage enhances pro-inflammatory and microbicidal responses, important for eradicating bacteria such as . By contrast, 'alternatively activated' M2 macrophages, polarized with IL-4, oppose bactericidal mechanisms and allow mycobacterial growth.

l-methionine Adenosylation: Radical Intermediates and the Catalytic Competence of the 5'-Deoxyadenosyl Radical.

Radical -adenosyl-l-methionine (SAM) enzymes employ a [4Fe-4S] cluster and SAM to initiate diverse radical reactions via either H-atom abstraction or substrate adenosylation. Here we use freeze-quench techniques together with electron paramagnetic resonance (EPR) spectroscopy to provide snapshots of the reaction pathway in an adenosylation reaction catalyzed by the radical SAM enzyme pyruvate formate-lyase activating enzyme on a peptide substrate containing a dehydroalanine residue in place of the target glycine. The reaction proceeds via the initial formation of the organometallic intermediate Ω, as evidenced by the characteristic EPR signal with = 2.

Aggregation of protein therapeutics enhances their immunogenicity: causes and mitigation strategies.

Protein aggregation in biotherapeutics has been identified to increase immunogenicity, leading to immune-mediated adverse effects, such as severe allergic responses including anaphylaxis. The induction of anti-drug antibodies (ADAs) moreover enhances drug clearance rates, and can directly block therapeutic function. In this review, identified immune activation mechanisms triggered by protein aggregates are discussed, as well as physicochemical properties of aggregates, such as size and shape, which contribute to immunogenicity.

Mesoporous Carbon Microfibers for Electroactive Materials Derived from Lignocellulose Nanofibrils.

The growing adoption of biobased materials for electronic, energy conversion, and storage devices has relied on high-grade or refined cellulosic compositions. Herein, lignocellulose nanofibrils (LCNF), obtained from simple mechanical fibrillation of wood, are proposed as a source of continuous carbon microfibers obtained by wet spinning followed by single-step carbonization at 900 °C. The high lignin content of LCNF (∼28% based on dry mass), similar to that of the original wood, allowed the synthesis of carbon microfibers with a high carbon yield (29%) and electrical conductivity (66 S cm).

Mycobacterial -Hydroxybenzoic Acid-Derivatives (HBADs) and Related Structures Induce Macrophage Innate Memory.

Macrophages are key immune cells for combatting . However, possesses means to evade macrophage bactericidal responses by, for instance, secretion of the immunomodulatory -hydroxybenzoic acid derivatives (HBADs). While these molecules have been implicated in inhibiting macrophage responses in an acute context, little is known about their ability to reprogram macrophages via induction of long-term innate memory.

Pristine graphene induces innate immune training.

Graphene-based materials are of increasing interest for their potential use in biomedical applications. However, there is a need to gain a deeper understanding of how graphene modulates biological responses before moving towards clinical application. Innate immune training is a recently described phenomenon whereby cells of the innate immune system are capable of being programmed to generate an increased non-specific response upon subsequent challenge.

Coaxial Spinning of All-Cellulose Systems for Enhanced Toughness: Filaments of Oxidized Nanofibrils Sheathed in Cellulose II Regenerated from a Protic Ionic Liquid.

Hydrogels of TEMPO-oxidized nanocellulose were stabilized for dry-jet wet spinning using a shell of cellulose dissolved in 1,5-diazabicyclo[4.3.0]non-5-enium propionate ([DBNH][COEt]), a protic ionic liquid (PIL).

Effects of non-solvents and electrolytes on the formation and properties of cellulose I filaments.

Coagulation is a critical process in the assembly of cellulose nanofibrils into filaments by wet spinning; however, so far, the role of the coagulation solvent has not been systematically elucidated in this context. This work considers organic non-solvents (ethanol, acetone) and aqueous electrolyte solutions (NaCl(aq), HCl(aq), CaCl(aq)) for the coagulation of negatively charged cellulose nanofibrils via wet spinning. The associated mechanisms of coagulation with such non-solvents resulted in different spinnability, coagulation and drying time.

Conductive Carbon Microfibers Derived from Wet-Spun Lignin/Nanocellulose Hydrogels.

We introduce an eco-friendly process to dramatically simplify carbon microfiber fabrication from biobased materials. The microfibers are first produced by wet-spinning in aqueous calcium chloride solution, which provides rapid coagulation of the hydrogel precursors comprising wood-derived lignin and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (TOCNF). The thermomechanical performance of the obtained lignin/TOCNF filaments is investigated as a function of cellulose nanofibril orientation (wide angle X-ray scattering (WAXS)), morphology (scanning electron microscopy (SEM)), and density.

Surface Structuring and Water Interactions of Nanocellulose Filaments Modified with Organosilanes toward Wearable Materials.

Colloidal dispersions of cellulose nanofibrils (CNFs) are viable alternatives to cellulose II dissolutions used for filament spinning. The porosity and water vapor affinity of CNF filaments make them suitable for controlled breathability. However, many textile applications also require water repellence.

Absorbent Filaments from Cellulose Nanofibril Hydrogels through Continuous Coaxial Wet Spinning.

A continuous and scalable method for the wet spinning of cellulose nanofibrils (CNFs) is introduced in a core/shell configuration. Control on the interfacial interactions was possible by the choice of the shell material and coagulant, as demonstrated here with guar gum (GG) and cellulose acetate (CA). Upon coagulation in acetone, ethanol, or water, GG and CA formed supporting polymer shells that interacted to different degrees with the CNF core.

Targeted Strategies for Mucosal Vaccination.

Mucosal immune responses are in the first line of defense against most infections and protective mucosal immunity can be achieved by mucosal vaccination. However, mucosal tolerance and physicochemical features of the mucosal environment pose challenging obstacles to the development of mucosal vaccines. Vaccine formulations must be designed to enhance stability at the mucosae and incorporate features that induce innate immunity at mucosal inductive sites.

Therapeutic potential of carbohydrates as regulators of macrophage activation.

It is well established for a broad range of disease states, including cancer and Mycobacterium tuberculosis infection, that pathogenesis is bolstered by polarisation of macrophages towards an anti-inflammatory phenotype, known as M2. As these innate immune cells are relatively long-lived, their re-polarisation to pro-inflammatory, phagocytic and bactericidal "classically activated" M1 macrophages is an attractive therapeutic approach. On the other hand, there are scenarios where the resolving inflammation, wound healing and tissue remodelling properties of M2 macrophages are beneficial - for example the successful introduction of biomedical implants.

The Emergence of Phenolic Glycans as Virulence Factors in Mycobacterium tuberculosis.

Tuberculosis is the leading infectious cause of mortality worldwide. The global epidemic, caused by Mycobacterium tuberculosis, has prompted renewed interest in the development of novel vaccines for disease prevention and control. The cell envelope of M.

Filaments with Affinity Binding and Wet Strength Can Be Achieved by Spinning Bifunctional Cellulose Nanofibrils.

We demonstrate benzophenone (BP) conjugation via amine-reactive esters onto oxidized cellulosic fibers that were used as precursors, after microfluidization, of photoactive cellulose nanofibrils (CNF). From these fibrils, cellulose I filaments were synthesized by hydrogel spinning in an antisolvent followed by fast biradical UV cross-linking. As a result, the wet BP-CNF filaments retained extensively the original dry strength (a remarkable ∼80% retention).

Strength and Water Interactions of Cellulose I Filaments Wet-Spun from Cellulose Nanofibril Hydrogels.

Hydrogels comprising cellulose nanofibrils (CNF) were used in the synthesis of continuous filaments via wet-spinning. Hydrogel viscosity and spinnability, as well as orientation and strength of the spun filaments, were found to be strongly affected by the osmotic pressure as determined by CNF surface charge and solid fraction in the spinning dope. The tensile strength, Young's modulus and degree of orientation (wide-angle X-ray scattering, WAXS) of filaments produced without drawing were 297 MPa, 21 GPa and 83%, respectively, which are remarkable values.

Molecular Diagnosis of Hemorrhagic Fever with Renal Syndrome Caused by Puumala Virus.

Rodent-borne hantaviruses cause two severe acute diseases: hemorrhagic fever with renal syndrome (HFRS) in Eurasia, and hantavirus pulmonary syndrome (HPS; also called hantavirus cardiopulmonary syndrome [HCPS]) in the Americas. Puumala virus (PUUV) is the most common causative agent of HFRS in Europe. Current routine diagnostic methods are based on serological analyses and can yield inconclusive results.

Structural activity relationship analysis (SAR) and in vitro testing reveal the anti-ageing potential activity of acetyl aspartic acid.

Background: Acetyl aspartic acid (A-A-A) was discovered through gene array analysis with corresponding connectivity mapping (Cmap), aiming for identification of new compounds with anti-ageing properties.

Objective: The aim of this study was to use structural activity relationship (SAR) analysis to identify a predictive mechanism of action of A-A-A. The findings from SAR will be further characterized by in vitro activity testing.

Nurse's perspectives on care provided for patients with gamma-hydroxybutyric acid and gamma-butyrolactone abuse.

Aims And Objectives: To describe registered nurses' views and experiences providing care for gamma-hydroxybutyric acid and gamma-butyrolactone abuse inpatients in a psychiatric unit.

Background: Gamma-hydroxybutyric acid and gamma-butyrolactone are illegal drugs with potentially fatal outcomes that are entering wider use in Scandinavia. Gamma-hydroxybutyric acid-dependent persons with withdrawal symptoms often require forceful withdrawal treatment provided in psychiatric units.