Spirochetes are helical bacteria consisting of an outer sheath, a protoplasmic cylinder and periplasmic flagella. All oral anaerobic spirochetes (OAS) are species within the genus Treponema. They are important causative agents of periodontitis. This thesis examines some aspects of the physiology of OAS. As well, a novel symbiotic bacterium found in the blood of healthy humans was studied as a consequence of my work with OAS. / Our lab has been instrumental in rendering routine and reliable growth of OAS in vitro. An inexpensive medium which remains molten at 37°C and solidifies at 25°C was found for the enumeration of colony-forming units of OAS. New Oral Spirochete (NOS) medium with the addition of 0.5% gelatin-0.5% Noble agar met the above criteria. / Clinical isolates of spirochetes from the periodontal pocket need to be readily identified. Restriction fragment length polymorphism (RFLP) analysis was used on reference strains of Treponema denticola, T. vincentii, T. phagedenis, and T. socranskii as well as a number of clinical isolates in our laboratory collection. The banding patterns observed allowed discrimination between the different spirochete species. / Morphological variations such as spherical-shaped cells of T. denticola, termed "spherical bodies" are occasionally observed. The omission of the several individual components from NOS medium (brain heart infusion, yeast extract, rabbit serum, volatile fatty acids, or thiamine pyrophosphate), the age of the culture and the addition of lactic acid, enhanced the formation of these bodies. / J. Miklossy (NeuroReport, 1993) reported that spirochetes were found in blood, cerebral cortex and cerebral spinal fluid in autopsied Alzheimer's Disease (AD) subjects. It was suggested by her that spirochetes could be a causative factor in AD. Our laboratory attempted to duplicate these results and found spirochetes in the blood of only one late stage AD patient suggesting that spirochetes are not one of the causes of AD. / During the examination of blood by darkfield microscopy, we observed pleomorphic microorganisms. Blood of a healthy human is a sterile environment. Evidence for the existence of bacteria in blood includes light and electron micrographs of their morphology, and molecular analysis of their 16S ribosomal RNA and their gyrB gene.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.36075 |
| Date | January 1999 |
| Creators | McLaughlin, Richard. |
| Contributors | Chan, E. C. S. (advisor) |
| Publisher | McGill University |
| 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 |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Faculty of Dentistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001651357, proquestno: NQ55421, Theses scanned by UMI/ProQuest. |
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