Comprehensive Bioenergetic Evaluation of Microbial Pathway Variants in Syntrophic Propionate Oxidation.

In this work, a systematic methodology was developed (based on known biochemistry, physiology, and bioenergetics) for the automated feasibility evaluation and net ATP yield quantification of large sets of pathway variants. Possible pathway variants differ in their intermediate metabolites, in which electron carriers are involved, in which steps are consuming/producing ATP, and in which steps are coupled to (and to how many) proton (or its equivalent) translocations. A pathway variant is deemed feasible, under a given set of physiological and environmental conditions, only if all pathway reaction steps have nonpositive Gibbs energy changes and if all the metabolite concentrations remain within an acceptable physiological range (10 to 10 M).

Efficient Screening for Ternary Molecular Ionic Cocrystals Using a Complementary Mechanosynthesis and Computational Structure Prediction Approach.

The discovery of molecular ionic cocrystals (ICCs) of active pharmaceutical ingredients (APIs) widens the opportunities for optimizing the physicochemical properties of APIs whilst facilitating the delivery of multiple therapeutic agents. However, ICCs are often observed serendipitously in crystallization screens and the factors dictating their crystallization are poorly understood. We demonstrate here that mechanochemical ball milling is a versatile technique for the reproducible synthesis of ternary molecular ICCs in less than 30 min of grinding with or without solvent.

Microbial growth under supercritical CO2.

Growth of microorganisms in environments containing CO2 above its critical point is unexpected due to a combination of deleterious effects, including cytoplasmic acidification and membrane destabilization. Thus, supercritical CO2 (scCO2) is generally regarded as a sterilizing agent. We report isolation of bacteria from three sites targeted for geologic carbon dioxide sequestration (GCS) that are capable of growth in pressurized bioreactors containing scCO2.

Direct enrichment of perchlorate-reducing microbial community for efficient electroactive perchlorate reduction in biocathodes.

Biological reduction of perchlorate (ClO₄⁻) has emerged as a promising solution for the removal of perchlorate in contaminated water and soils. In this work, we demonstrate a simple process to enrich perchlorate-reducing microbial communities separately using acetate as electron donor and the municipal aerobic membrane bioreactor sludge as inoculum. Inoculation of cathodes in microbial fuel cells (MFCs) with these enrichments, and further electrochemical enrichment at constant resistance operation of the MFCs, led to perchlorate-reducing biocathodes with peak reduction rates of 0.

Crystal structures of the GCaMP calcium sensor reveal the mechanism of fluorescence signal change and aid rational design.

The genetically encoded calcium indicator GCaMP2 shows promise for neural network activity imaging, but is currently limited by low signal-to-noise ratio. We describe x-ray crystal structures as well as solution biophysical and spectroscopic characterization of GCaMP2 in the calcium-free dark state, and in two calcium-bound bright states: a monomeric form that dominates at intracellular concentrations observed during imaging experiments and an unexpected domain-swapped dimer with decreased fluorescence. This series of structures provides insight into the mechanism of Ca2+-induced fluorescence change.

Direct electrochemical analyses of a thermophilic thioredoxin reductase: interplay between conformational change and redox chemistry.

Thioredoxin reductases (TrxRs) are flavin-containing dithioloxidoreductases that couple reduction equivalents from the soluble NAD(P)H pool to the soluble protein thioredoxin (Trx). Previous crystallographic studies of the Escherichia coli enzyme ( ecTrxR) have shown that low molecular weight TrxRs can adopt two distinct conformations: the first (FO) is required for the oxidation of the flavin cofactor and the generation of reduced Trx; the second (FR) is adopted for the reduction of the flavin by NAD(P)H. Here, protein electrochemistry has been used to interrogate the equilibrium between the oxidized and reduced conformations of the ecTrxR and a novel, low molecular weight TrxR from the thermophilic archaeon Thermoplasma acidophilum ( taTrxR) that is characterized structurally and biochemically in the accompanying paper [Hernandez et al.

Thioredoxin reductase from Thermoplasma acidophilum: a new twist on redox regulation.

Thioredoxin reductases (TrxRs) regulate the intracellular redox environment by using NADPH to provide reducing equivalents for thioredoxins (Trxs). Here we present the cloning and biochemical characterization of a putative TrxR (Ta0984) and a putative Trx (Ta0866) from Thermoplasma acidophilum. Our data identify Ta0866 as a Trx through its capacity to reduce insulin and be reduced by Escherichia coli TrxR in a NADPH-dependent manner.

Formation and evolution of structure in loop cosmology.

Inhomogeneous cosmological perturbation equations are derived in loop quantum gravity, taking into account corrections, in particular, in gravitational parts. This provides a framework for calculating the evolution of modes in structure formation scenarios related to inflationary or bouncing models. Applications here are corrections to the Newton potential and to the evolution of large scale modes which imply nonconservation of curvature perturbations possibly noticeable in a running spectral index.

Immunogenicity and safety assessment of the Cuban recombinant hepatitis B vaccine in healthy adults.

Manufactures of biotechnological/biological products (including vaccines) frequently make changes to manufacturing processes of products both during development and after approval. In our case, a non-inferiority bridging study was carried out to demonstrate that changes in the production plant facilities of Cuban recombinant hepatitis B vaccine, Heberbiovac HB, did not affect the safety and immunogenicity of the vaccine. This controlled, randomized, doubled-blinded trial included 501 volunteers, aged between 20 and 64, who were given three doses of vaccine (20 microg HBsAg/mL) at month 0, 1, and 2.

Synthesis and bacterial expression of a gene encoding the heme domain of assimilatory nitrate reductase.

Assimilatory NADH:nitrate reductase (EC 1.6.6.