Proteome profiling by label‐free mass spectrometry reveals differentiated response of Campylobacter jejuni 81–176 to sublethal concentrations of bile acids.

Purpose Bile acids are crucial components of the intestinal antimicrobial defense and represent a significant stress factor for enteric pathogens. Adaptation processes of Campylobacter jejuni to this hostile environment are analyzed in this study by a proteomic approach. Experimental design Proteome profiling by label-free mass spectrometry (SWATH-MS) has been used to characterize the adaptation of C. jejuni to sublethal concentrations of seven bile acids. Results The bile acids with the lowest inhibitory concentration (IC50), deoxycholic and chenodeoxycholic acid, induce the most significant proteome changes. Overall a downregulation of all basic biosynthetic pathways and a general decrease in the transcription machinery are found. Concurrently, an induction of factors involved in detoxification of reactive oxygen species, protein folding, and bile acid exporting efflux pumps is detected. Exposure to deoxycholic and chenodeoxycholic acid results in an increased expression of components of the more energy-efficient aerobic respiration pathway, while the anaerobic branches of the electron transport chain are down-expressed. Conclusions and clinical relevance The results show that C. jejuni has a differentiated system of adaptation to bile acid stresses. The findings enhance the understanding of the pathogenesis of campylobacteriosis, especially for survival of C. jejuni in the human intestine, and may provide clues to future medical treatment

Trapping of Projectiles in Fixed Scatterer Calculations

We study multiple scattering off nuclei in the closure approximation. Instead of reducing the dynamics to one particle potential scattering, the scattering amplitude for fixed target configurations is averaged over the target groundstate density via stochastic integration. At low energies a strong coupling limit is found which can not be obtained in a first order optical potential approximation. As its physical explanation, we propose it to be caused by trapping of the projectile. We analyse this phenomenon in mean field and random potential approximations. (PACS: 24.10.-i)Comment: 15 page

Nasal carriage of Staphylococcus aureus treated with topical mupirocin (pseudomonic acid) in a children's hospital

2% mupirocin ointment applied intra-nasally for 5 days was assessed for elimination of nasal carriage of Staphylococcus aureus in 31 staff members in a children's hospital. Three volunteers failed to complete the trial because of side effects, i.e. buccal reddening and swelling, and unpleasant taste. During treatment staphylococcal nasal carriage was not found in any case; of the 24 post-treatment nasal swabs taken 4 days after treatment 22 were still negative. Re-colonization with S. aureus of different phage types occurred in the remaining two cases

Discrete Accidental Symmetry for a Particle in a Constant Magnetic Field on a Torus

A classical particle in a constant magnetic field undergoes cyclotron motion on a circular orbit. At the quantum level, the fact that all classical orbits are closed gives rise to degeneracies in the spectrum. It is well-known that the spectrum of a charged particle in a constant magnetic field consists of infinitely degenerate Landau levels. Just as for the $1/r$ and $r^2$ potentials, one thus expects some hidden accidental symmetry, in this case with infinite-dimensional representations. Indeed, the position of the center of the cyclotron circle plays the role of a Runge-Lenz vector. After identifying the corresponding accidental symmetry algebra, we re-analyze the system in a finite periodic volume. Interestingly, similar to the quantum mechanical breaking of CP invariance due to the $\theta$-vacuum angle in non-Abelian gauge theories, quantum effects due to two self-adjoint extension parameters $\theta_x$ and $\theta_y$ explicitly break the continuous translation invariance of the classical theory. This reduces the symmetry to a discrete magnetic translation group and leads to finite degeneracy. Similar to a particle moving on a cone, a particle in a constant magnetic field shows a very peculiar realization of accidental symmetry in quantum mechanics.Comment: 25 pages, 2 figure

Transverse QCD Dynamics Near the Light Cone

Starting from the QCD Hamiltonian in near-light cone coordinates, we study the dynamics of the gluonic zero modes. Euclidean 2+1 dimensional lattice simulations show that the gap at strong coupling vanishes at intermediate coupling. This result opens the possibility to synchronize the continuum limit with the approach to the light cone.Comment: 15 pages, LaTeX, 3 figures (7 PS files

Next-to-Leading Order QCD Corrections to the Lifetime Difference of BsB_s Mesons

We compute the QCD corrections to the decay rate difference in the $B_s-\bar B_s$ system, $\Delta\Gamma_{B_s}$, in the next-to-leading logarithmic approximation using the heavy quark expansion approach. Going beyond leading order in QCD is essential to obtain a proper matching of the Wilson coefficients to the matrix elements of local operators from lattice gauge theory. The lifetime difference is reduced considerably at next-to-leading order. We find $(\Delta\Gamma/\Gamma)_{B_s}=(f_{B_s}/210 MeV)^2 [0.006 B(m_b)+0.150 B_S(m_b)-0.063]$ in terms of the bag parameters $B, B_S$ in the NDR scheme. As a further application of our analysis we also derive the next-to-leading order result for the mixing-induced CP asymmetry in inclusive $b\to u\bar ud$ decays, which measures $\sin 2\alpha$.Comment: 14 pages, LaTeX, 1 figure; minor modifications of the text, improved discussion of eq. (35), all results unchange

Test of Lorentz Symmetry by using a 3He/129Xe Co-Magnetometer

To test Lorentz symmetry we used a 3He/129Xe co-magnetometer. We will give a short summary of our experimental setup and the results of our latest measurements. We obtained preliminary results for the equatorial component of the background field interacting with the spin of the bound neutron: b_n < 3.72 x 10^(-32) GeV (95 C.L.).Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 28 - July 2, 201

Dewetting of thin films on heterogeneous substrates: Pinning vs. coarsening

We study a model for a thin liquid film dewetting from a periodic heterogeneous substrate (template). The amplitude and periodicity of a striped template heterogeneity necessary to obtain a stable periodic stripe pattern, i.e. pinning, are computed. This requires a stabilization of the longitudinal and transversal modes driving the typical coarsening dynamics during dewetting of a thin film on a homogeneous substrate. If the heterogeneity has a larger spatial period than the critical dewetting mode, weak heterogeneities are sufficient for pinning. A large region of coexistence between coarsening dynamics and pinning is found.Comment: 4 pages, 4 figure