Cholera- and Anthrax-Like Toxins Are among Several New ADP-Ribosyltransferases

Chelt, a cholera-like toxin from Vibrio cholerae, and Certhrax, an anthrax-like toxin from Bacillus cereus, are among six new bacterial protein toxins we identified and characterized using in silico and cell-based techniques. We also uncovered medically relevant toxins from Mycobacterium avium and Enterococcus faecalis. We found agriculturally relevant toxins in Photorhabdus luminescens and Vibrio splendidus. These toxins belong to the ADP-ribosyltransferase family that has conserved structure despite low sequence identity. Therefore, our search for new toxins combined fold recognition with rules for filtering sequences – including a primary sequence pattern – to reduce reliance on sequence identity and identify toxins using structure. We used computers to build models and analyzed each new toxin to understand features including: structure, secretion, cell entry, activation, NAD+ substrate binding, intracellular target binding and the reaction mechanism. We confirmed activity using a yeast growth test. In this era where an expanding protein structure library complements abundant protein sequence data – and we need high-throughput validation – our approach provides insight into the newest toxin ADP-ribosyltransferases

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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Membrane permeabilization by conjugated oligoelectrolytes accelerates whole-cell catalysis

Conjugated oligoelectrolytes (COEs) boost the electrical performance of a wide range of bioelectrochemical systems, yet their mechanism of action remains incompletely understood. One possible mode of action is that COEs permeabilize the cell envelope. We thus examined the effect of tetracationic COE, DSSN+, on the permeability of the inner and outer membrane of Escherichia coli by detecting extracellular activity of normally periplasmic and cytoplasmic enzymes. DSSN+ increases the release of the periplasmic enzyme alkaline phosphatase (ALP) up to 20-fold, but does not significantly change the release of the cytoplasmic enzyme β-galactosidase. Additionally, DSSN+ caused a 2-fold increase in the turnover of a cytoplasmic substrate. These studies present a more complete understanding of the mechanism of action in bioelectrochemical systems and pivot future applications of COEs towards a method for improving whole-cell catalysis

Significance of Average Domain Purity and Mixed Domains on the Photovoltaic Performance of High-Efficiency Solution-Processed Small-Molecule BHJ Solar Cells

Whereas the role of molecularly mixed domains in organic photovoltaic devices for charge generation is extensively discussed in the literature, the impact on charge recombination and thus fill factor is largely unexplored. Here, a combination of soft X-ray techniques enables the quantification of phases at multiple length scales to reveal their role regarding charge recombination in a highly efficient solution processed small molecule system 7,7′-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b′]dithiophene-2,6-diyl)bis(6-fluoro-4-(5′-hexyl-[2,2′-bithiophen]-5-yl)benzo[c][1,2,5]thiadiazole) (p-DTS(FBTTh2)2). A quantitative (linear) relationship between the average composition variations and the device fill-factor is observed. The results establish the complex interrelationship between average phase purity, domain size, and structural order and highlight the requirement of achieving sufficient phase purities to diminish bimolecular and geminate recombination in solution processed small molecule solar cells

Importance of domain purity and molecular packing in effi cient solution-processed small-molecule solar cells

Organic solar cells made from a solution-processed blend of electron-donating and electron-accepting small molecules have been demonstrated to be viable alternatives to their conjugated polymer-based or evaporated small molecule counterparts. As in polymer-based devices, controlling and understanding the surprisingly complex nanoscale morphology of the active layer in molecular bulk heterojunction (BHJ) devices remains a principal challenge. For most BHJ systems, improved solar cell performance has been achieved by varying the film-processing conditions often leading to a distinctly different morphology from those seen in lower performing devices. In addition to size and composition variation (purity), molecular ordering relative to the dominant, discrete donor-acceptor interface can also be a critical structure parameter that impacts performance