A Chlamydia effector recruits CEP170 to reprogram host microtubule organization

The obligate intracellular bacterial pathogen Chlamydia trachomatis deploys virulence effectors to subvert host cell functions enabling its replication within a specialized membrane-bound compartment termed an inclusion. The control of the host cytoskeleton is critical for Chlamydia uptake, inclusion biogenesis and cell exit. Here we demonstrate how a Chlamydia effector rearranges the microtubule network by initiating organization of the microtubules at the inclusion surface. We identified an inclusion-localized effector sufficient to interfere with microtubule assembly that we term inclusion protein acting on microtubules (IPAM). We established that IPAM recruits and stimulates the centrosomal protein 170kDa (CEP170) to hijack the microtubule organizing functions of the host cell. We show that CEP170 is essential for chlamydial control of host microtubule assembly, and is required for inclusion morphogenesis and bacterial infectivity. Together, we demonstrate how a pathogen effector reprograms the host microtubule network to support its intracellular development

Epimerization of trans-4-hydroxy--proline to cis-4-hydroxy--proline during acid hydrolysis of collagen

1. 1. trans-4-Hydroxy--proline is epimerized to cis-4-hydroxy--proline under the conditions generally used for the hydrolysis of proteins for analyses of amino acids.2. 2. The cis epimer elutes from a column of UR-30 resin on a Beckman amino acid analyzer at the same time as threonine and hence would be undetected.3. 3. About 8% of the trans-4-hydroxy--proline in collagen can be epimerized to cis-4-hydroxy--proline in the hydrolysis of collagen with 6 N HCl at 110[deg] for 72 hr.4. 4. A procedure is described whereby the primary amino acids in hydrolyzates are deaminated with nitrous acid and removed so that the amounts of trans-4-hydroxyproline, cis-4-hydroxyproline, and proline can be determined without changing the temperature of the column of UR-30 resin on the Beckman amino acid analyzer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34027/1/0000304.pd

Discovery of very high energy gamma-ray emission coincident with molecular clouds in the W28 (G6.4-0.1) field

We observed the W28 field (for ~40 h) at Very High Energy (VHE) gamma-ray energies (E>0.1 TeV) with the H.E.S.S. Cherenkov telescopes. A reanalysis of EGRET E>100 MeV data was also undertaken. Results from the NANTEN 4m telescope Galactic plane survey and other CO observations have been used to study molecular clouds. We have discovered VHE gamma-ray emission (HESSJ1801-233) coincident with the northeastern boundary of W28, and a complex of sources (HESSJ1800-240A, B and C) ~0.5 deg south of W28, in the Galactic disc. The VHE differential photon spectra are well fit by pure power laws with indices Gamma~2.3 to 2.7. The NANTEN ^{12}CO(J=1-0) data reveal molecular clouds positionally associating with the VHE emission, spanning a ~15 km s^{-1} range in local standard of rest velocity. The VHE/molecular cloud association could indicate a hadronic origin for HESSJ1801-233 and HESSJ1800-240, and several cloud components in projection may contribute to the VHE emission. The clouds have components covering a broad velocity range encompassing the distance estimates for W28 (~2 kpc), and extending up to ~4 kpc. Assuming a hadronic origin, and distances of 2 and 4 kpc for cloud components, the required cosmic ray density enhancement factors (with respect to the solar value) are in the range ~10 to ~30. If situated at 2 kpc distance, such cosmic ray densities may be supplied by a SNR like W28. Additionally and/or alternatively, particle acceleration may come from several catalogued SNRs and SNR candidates, the energetic ultra compact HII region W28A2, and the HII regions M8 and M20 along with their associated open clusters. Further sub-mm observations would be recommended to probe in detail the dynamics of the molecular clouds at velocites >10 km s^{-1}, and their possible connection to W28.Comment: 10 pages, 4 figures. Accepted for publication in Astronomy & Astrophysics. (Abstract shortened

Chemical and Microstructural Effects in Electrode Polarization

This presentation discusses the chemical and microstructural effects in electrode polarization and a relative comparison of contributions of the various polarizations in anode-supported cells