Hasil untuk "hep-ex"

M. Muñoz, M. Rosso, F. J. Aguilar et al.

B. Deurs, P. Holm, Lars Kayser et al.

Manuela G. Neuman, Neil H. Shear, S. Bellentani et al.

D. Evans, D. Evans, David Y. Graham

C. Fiorentini, G. Arancia, A. Caprioli et al.

Jen Ren Wang, Murray W. Stinson

Shu-jing Wu, L. Ng, D. Lin et al.

L. Bermudez, Lowell S. Young, Kuzell

S. Rooney, M. Ryan

Kwang-Youl Lee, Y. Lee, Shin Il Kim et al.

H. Doostdar, S. Duthie, M. Burke et al.

J. Janda, S L Abbott, L S Oshiro

S. Kevekordes, J. Spielberger, Burghaus Cm et al.

M. Mckee, A. O’Brien

D. Heuer, V. Brinkmann, T. Meyer et al.

Chlamydial protease‐like activity factor (CPAF) is secreted to the cytoplasm of the infected cells where it proteolytically cleaves eukaryotic transcription factor RFX5. Here, we determined the localization pattern of CPAF during the course of an acute and persistent in vitro infection of the epithelial cell line HEp‐2 with Chlamydophila pneumoniae strain VR1310. Using immunoblotting, confocal microscopy and electron microscopy, we found CPAF in the inclusion lumen or associated with bacteria during the first 48 h of an acute infection. Seventy‐two hours and later, CPAF was present predominantly in the cytoplasm of the infected cells. Translocation of CPAF into cytoplasm correlated in time with degradation of the transcription factor RFX5, as confirmed by immunoblotting. Interestingly, during the persistent infection induced by either IFN‐γ or iron limitation CPAF translocation to the cytoplasm was inhibited resulting in unaffected or only partially reduced levels of RFX5. Based on presented findings, we propose that CPAF translocation to the cytoplasm is separated from its production. The translocation mechanism appears to be fully active during an acute infection; however, it is fully or partially inhibited during persistent infection induced by IFN‐γ or by iron limitation respectively. Consequently, this work demonstrates the importance of subcellular localization of CPAF for the characteristics of chlamydial acute and persistent infection in epithelial HEp‐2 cells.

M. Polo, M. D. de Bravo

Firouz Darroudi, C. Meijers, V. Hadjidekova et al.

Christine M. Sanfilippo, F. N. W. Chirimuuta, J. Blaho

Sang-Hyun Kim, Yong-Hwan Kim

Escherichia coli (E. coli) has ability to express thin aggregative fimbriae, known as curli, on the cell surface. Previously, a few example of curli expression in serogroup O157:H7 of enterohemorrhagic E. coli (EHEC) were reported, compared to other E. coli groups. However, significance of curliation in the EHEC pathobiology has not been described well in the literature. A highly curliated O157:H7 strain was used in this study in order to elucidate role of curliation in EHEC adherence to cultured HEp-2 cells. The expression of curli in the EHEC isolate was consistent with strong positive indication of Congo-red (CR) binding and formation of clumps in the bottom of the tube containing Luria-Bertani (LB) broth when cultured overnight at 37 degrees C. A few CR-binding negative (CR-) colonies occurred spontaneously within the population of CR+ isolate. The CR+ EHEC showed massive aggregative adhesion pattern, whereas the spontaneous CR- strain showed typical localized adherence on HEp-2 cells. Electron microscopy confirmed highly curliated bacteria in the CR+ EHEC sample. Interestingly, the curliation disappeared in a msbB1 and msbB2 double mutant derived from the CR+ EHEC. These results suggest that the compromised outer membrane integrity caused by msbB mutations may abrogate curli production in the CR+ EHEC harbouring penta-acylated lipid A structure in their outer membrane.

D. Villari, R. Caruso, M. Grosso et al.