Campylobacter jejuni is a human pathogen that causes severe diarrhea! disease. However,
our understanding of C. jejuni virulence mechanisms and survival during disease and
transmission remains limited. Amino acid ATP Binding Cassette (AA-ABC) transporters in C.
jejuni have been proposed as being important for bacterial physiology and pathogenesis. We
have investigated a novel AA-ABC transporter system, encoded by cj0467-9, by generating
targeted deletions of cj0467 (membrane transport component) and cj0469 (ATPase component)
in C. jejuni 81-176. Analyses described herein have led us to designate these genes paqP and
paqQ, respectively [pathogenesis-ssociated glutamine (q) ABC transporter permease () and
ATPase (Q)]. We found that loss of either component resulted in amino acid uptake defects,
most notably diminished glutamine uptake. Both ΔpaqP and ΔpaqQ mutants also exhibited a
surprising but significant increase in short-term intracellular survival in macrophages and
epithelial cells. Levels of resistance to a series of environmental and in vivo stresses were
examined. Both mutants were hyper-resistant to aerobic and oxidative stress, and while ΔpaqP
was also hyper-resistant to heat and osmotic shock, ΔpaqQ was more susceptible than wild-type
to the latter two stresses. Annexin-V staining coupled with fluorescence microscopy revealed
that macrophages infected with the ΔpaqP and ΔpaqQ mutants underwent a lower level of
apoptosis than cells infected with wild-type bacteria. Macrophages infected with the mutant
strains exhibited a transient decrease in ERK activation compared to wild type-infected
macrophages, potentially explaining the reduced apoptosis phenotype. The ΔpaqP mutant did not
exhibit a defect for short or longer term mouse colonization, consistent with its increased stress
survival and diminished host cell damage phenotypes. Collectively, these results demonstrate a
unique correlation between an AA-ABC transporter with bacterial stress tolerance, intracellular
survival, host cell damage, and host signal transduction in response to pathogen infection.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU.2429/4181 |
| Date | 11 1900 |
| Creators | Lin, Ann En-Ju |
| Publisher | University of British Columbia |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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