The mechanism of action of antimicrobial peptides depends on physicochemical properties such as structure, concentration, and oligomerization. Here, we focused on the effect of dimerization on the mechanism of action of aurein 1.2 (AU). We designed a lysine-linked AU dimer, (AU)(2)K, and its interaction with membrane mimetics was studied using four biophysical techniques and molecular dynamics simulations. Circular dichroism and molecular dynamics studies showed that AU displayed a typical spectrum for disordered structures in aqueous solution whereas (AU)(2)K exhibited the typical spectrum of alpha-helices in a coiled-coil conformation, wherein helices are wrapped around each other. With the addition of large unilamellar vesicles (LUVs), AU adopted an a-helix structure whereas the coiled-coil structure of (AU)(2)K assumed an extended conformation. Carboxyfluorescein release experiments with LUVs showed that both peptides were able to permeabilize vesicles although the leakage response to increases in peptide concentration differed. Optical microscopy experiments showed that both peptides induced pore opening and the dimer eventually caused the vesicles to burst. Finally, calorimetric traces determined by isothermal titration calorimetry on the LUVs also showed significant differences in peptide membrane interactions. Together, the results of our study demonstrated that dimerization changes the mechanism of action of AU. (C) 2016 Elsevier B.V. All rights reserved.

It is well known that cationic antimicrobial peptides (cAMPs) are potential microbicidal agents for the increasing problem of antimicrobial resistance. However, the physicochemical properties of each peptide need to be optimized for clinical use. To evaluate the effects of dimerization on the structure and biological activity of the antimicrobial peptide Ctx-Ha, we have synthesized the monomeric and three dimeric (Lys-branched) forms of the Ctx-Ha peptide by solid-phase peptide synthesis using a combination of 9-fluorenylmethyloxycarbonyl (Fmoc) and t-butoxycarbonyl (Boc) chemical approaches. The antimicrobial activity assay showed that dimerization decreases the ability of the peptide to inhibit growth of bacteria or fungi; however, the dimeric analogs displayed a higher level of bactericidal activity. In addition, a dramatic increase (50 times) in hemolytic activity was achieved with these analogs. Permeabilization studies showed that the rate of carboxyfluorescein release was higher for the dimeric peptides than for the monomeric peptide, especially in vesicles that contained sphingomyelin. Despite different biological activities, the secondary structure and pore diameter were not significantly altered by dimerization. In contrast to the case for other dimeric cAMPs, we have shown that dimerization selectively decreases the antimicrobial activity of this peptide and increases the hemolytic activity. The results also show that the interaction between dimeric peptides and the cell wall could be responsible for the decrease of the antimicrobial activity of these peptides.

The bodies produced by the violent practice of suicide bombing are a source of horror and disgust. They are, in feminist psychoanalyst Julia Kristeva's concept, abject: that which defies borders and is expelled to create the self. As abject bodies', suicide bombers' bodies frustrate attempts at calculation and rational control of security risks, and, in their mutilated flesh, expose as unstable the idea of the body as a whole with clearly defined boundaries between inside and outside. Female suicide bombers, whose bodies are already considered abject', produce a politics of the body that exceeds narratives of victimhood, and whose very monstrosity symbolically threatens the foundations of the nation-state. Attempts at constructing subjects out of the mutilated bodily remains of victims and perpetrators of suicide bombings are key practices in the production of the state and gendered subjects. The practice of suicide bombing and efforts to recover and resignify bodies reveals how power molds and constitutes the border of the body and state simultaneously. The explosive body of the suicide bomber thus has destabilizing effects beyond the motivations of its perpetrators and exposes the political work necessary to maintain the illusion of secure, bounded bodies and states.

In the title molecule, C(16)H(14)N(2)O, the dihedral angle between the two phenyl rings is 23.5 (6)degrees. In the crystal, N-H-O hydrogen bonds link molecules into chains running along the a axis.

In the title hydrazone derivative, C(15)H(13)ClN(2)O(2), the dihedral angle between the benzene rings is 2.36 (2)°. An intra-molecular N-H⋯O hydrogen bond is present. In the crystal, N-H⋯O and C-H⋯O hydrogen bonds link the mol-ecules into chains running parallel to the b axis.

We consider the structure of the N(H I)-E(B - V) relationship when Hi is measured in the 21 cm radio line and E(B - V) is defined by far-IR dust-derived measures. We derive reddening-dependent corrections to N(H I) based on interferometric absorption measurements over the past 30 yr that follow a single power-law relationship integral tau(H I)d v = 14.07 km s(-1) E(B - V)(1.074) at 0.02 less than or similar to E(B - V) less than or similar to 3 mag. Corrections to 21 cm line-derived H I column densities are too small to have had any effect on the ratio N(H I)/E(B - V) = 8.3 x 10(21) cm(-2) mag(-1) we derived at 0.015 less than or similar to E(B - V) less than or similar to 0.075 mag and |b| >= 20 degrees; they are also too small to explain the break in the slope of the N(H I)-E(B - V) relation at E(B - V) greater than or similar to 0.1 mag that we demonstrated around the Galaxy at |b| >= 20 degrees. The latter must therefore be attributed to the onset of H-2 formation and we show that models of H-2 formation in a low-density diffuse molecular gas can readily explain the inflected N (H I)-E(B-V) relationship. Below |b| = 20 degrees N(H I)/E(B-V) measured at 0.015 less than or similar to E(B - V) less than or similar to 0.075 mag increases steadily down to |b| = 8 degrees where sightlines with small E(B - V) no longer occur. By contrast, the ratio N(H I)/E(B - V) measured over all E(B - V) declines to N(H I)/E(B - V) = 5-6 x 10(21) cm(-2) mag(-1) at |b| less than or similar to 30 degrees, perhaps providing an explanation of the difference between our results and the gas/reddening ratios measured previously using stellar spectra.

In this article the Romagnolo locution fe(r) e' curdo(n) 'to purr' is considered in regard to its etymology. It is argued that the word curdo(n) 'string' is a paretymological reinterpretation of burdon 'burden, drone', a technical music term designating the lowest course of a lute and, more generally, a uniform bass accompaniment. Hence the locution would have been playfully applied to the purr of cats, whose noise resembles a bass accompaniment because of its low pitch and assiduity.

The asymmetric unit of the title compound, C(18)H(16)F(4)N(2), comprises two half crystallographically independent potentially bidentate Schiff base ligands, with an inversion centre located at the mid-point of the central C-C bond. The crystal packing is stabilized by intermolecular C-H center dot center dot center dot F and pi-pi interactions [centroid-centroid distance = 3.8283 (11) angstrom].

The most precise measurement of the electron neutrino mass has been obtained from the shape of the electron energy spectrum near the endpoint in tritium decay. The Mainz and Troitsk experiments indicated an excess instead of expected depletion of counts in that region. Results derived from such measurements are subject to numerous atomic corrections which are absent in the scattering e(-) p -> nv(e). This new idea is presented in the article, with its advantages and difficulties, and is compared to the method of tritium decay.