Chlamydiae are obligate intracellular pathogens that cause several serious
conditions within the human host. Many of the symptoms associated with infection
are thought to stem from the development of aberrant, or persistent, chlamydiae.
Factors leading to chlamydial persistence include deprivation of amino acids, the
release of certain cellular factors, or the addition of inhibitors of bacterial cell wall
or DNA synthesis. Such changes within the chlamydial environment often lead to
modifications in cell morphology, gene expression, chlamydial development, and
antigen localization. In this report, I examine changes in antigen production and
localization in Chlamydia-infected cells cultured in the presence of environmental
stressors. There are three major areas of chlamydial biology examined: 1) how do
the chlamydiae divide in the absence of FtsZ, 2) what is the importance of the
predicted peptidoglycan hydrolase, PapQ; 3) what changes occur in antigen
production and localization during the development of chlamydial persistence. One
significant nonproteinacious factor apparently involved in chlamydial division is
the SEP (septum) antigen, which localizes to the midcell of dividing chlamydiae.
Non-dividing forms, such as persistent chlamydiae and EB, lack the septal
placement of SEP, further suggesting the involvement of SEP in RB division. The
production of the predicted hydrolase, PapQ, localizes to the cytosol of RB and, to
a limited extent, within the EB. PapQ begins to accumulate as early as 12 hours
after infection and during the time of RB-EB transition, an additional, smaller
PapQ product accumulates. Ampicillin and tetracycline treatment inhibits
accumulation of the smaller product suggesting that PapQ may be processed by a
late expressed protease. This may have significance in RB-EB transition. The
IncA-laden fibers protruding from the inclusion and into the host cytosol colocalize
with a variety of different antigens that are generally restricted to the chlamydial
outer membrane. Changes in culture conditions leads to changes in the amount and
type of antigens localizing within the fibers. Chlamydial persistence dramatically
influences the production and localization of several chlamydial antigens, creating
significant changes in chlamydial cell biology that may enhance survival within the
host. / Graduation date: 2003
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/31652 |
| Date | 28 June 2002 |
| Creators | Brown, Wendy J. |
| Contributors | Rockey, Daniel D. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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