In order to gain a better understanding of this microorganismand its role in human pathogenesis, a physical map of Moraxella catarrhalis type strain ATCC25238 was constructed using pulsed field gel electrophoresis (PFGE) in combination with Southern hybridization techniques. Restriction endonucleases Not I, Rsr II, and Sma I were used to digest the chromosomal DNA. An overlapping circular map was generated by cross-hybridization of isolated radiolabeled fragments of Moraxella catarrhalis genomic DNA to dried PFGE gels. The number and location of the 16S and 23S ribosomal RNA genes were determined by digestion with l-Ceul enzyme and by Southern hybridization. Virulence-associated genes, the gene for β-lactamase, and housekeeping genes were also placed onto the physical map.

Dissertation (Ph.D.)--University of Toledo, 2009. / ["In partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biomedical Sciences."] Title from title page of PDF document. Bibliography: p. 80-112.

Thesis (Ph. D.) -- University of Texas Southwestern Medical Center at Dallas, 2004. / Vita. Bibliography: 214-244.

Thèse (M.Sc.)--Université Laval, 2000. / Bibliogr.: f. 64-79. Publié aussi en version électronique.

This thesis reports the characterisation of a novel outer membrane protein (OMP) from M. catarrhalis, designated M35, with a molecular mass of 36.1 kDa. This protein is structurally homologous to classic Gram-negative porins, such as OMP C from E. coli and OMP K36 from K. pneumoniae, with a predicted structure of 8 surface loops connecting 16 antiparallel -sheets. Comparison of the DNA sequences of the M35 genes from 18 diverse clinical isolates showed that the gene was highly conserved (99.6-100 % of nucleotides) with only one isolate (ID78LN266) having base variations that resulted in amino acid substitutions. A single amino acid mutation in the 3rd external loop of M35 in isolate ID78LN266 significantly affected antibody recognition, indicating that loop 3 contains an immunodominant B-cell epitope. The reduction in antibody-binding to M35 from ID78LN266 was similar to that caused by complete removal of loop 3. Since loop 3 folds into the porin channel in the classic structure, the antibody specificity to loop 3 was hypothesised to be a potential mechanism for evasion of host immune responses targeted to M35, potentially explaining the high degree of conservation across isolates. A series of recombinant proteins were constructed to analyse the binding to M35 of antibodies specificity for loop 3 or the remainder of the protein. It was found that loop 3- specific antibodies were not able to bind to M35 on the surface of M. catarrhalis and that this corresponds both with a lack of ability to enhance opsonophagocytosis in vitro and bacterial clearance in vivo. Additionally, antibodies raised against a version of M35 lacking loop 3 and M35 from the variant isolate ID78LN266 were both no less effective than the full consensus M35 by both these measures. It therefore appears that while the majority of antibodies raised against M35 are specific for loop 3 these antibodies do not mediate anti-M. catarrhalis actions. Two deletion mutant strains of M. catarrhalis that do not contain the outer membrane protein M35 were created by insertional inactivation of the M35 gene. Growth comparisons between these mutant strains and their wildtype parent strains initially led to the hypothesis that M35 is necessary for efficient glutamic acid uptake by M. catarrhalis, however this hypothesis was later shown to be incorrect. Efficient uptake of glutamic acid seemed to be mediated by a novel 40 kDa protein that was up-regulated in the deletion mutant strains, presumably to compensate for the lack of M35. M35 was also found to be essential for in vivo survival of M. catarrhalis in the nasal cavities of mice, indicating that it is an essential functional protein for colonisation of the mucosal surface.

Diss. (sammanfattning) Umeå : Univ., 2003. / Härtill 4 uppsatser.

Thesis (M.S.)--University of Toledo, 2008. / "In partial fulfillment of the requirements for the degree of Master of Science in Biomedical Sciences." Title from title page of PDF document. Non-Latin script record Bibliography: pages 74-92.

Bacterial aspartate transcarbamoylases (ATCase's) are divided into three classes that correspond to taxonomic relationships within the bacteria. The opportunistic pathogen Moraxeila catarrhalis has undergone several reclassifications based on traditional microbiological criteria. The previously uncharacterized ATCase from M. catarrhalis was purified to homogeneity and its chemical properties characterized. The ATCase from M. catarrhalis is a class C ATCase with an apparent molecular mass of 480-520 kDa. The M. catarrhalis ATCase is a dodecomer composed of six 35 kDa polypeptides and six 45 kDa polypeptides. The enzyme has an unusually high pH optimum of greater than pH 10. The enzyme exhibited hyperbolic kinetic with a Km for aspartate of 2 mM. A single, separate 78 kDa dihydroorotase from M. catarrhalis was identified and it was not associated with ATCase. These data support the reclassification of M. catarrhalis out of the Neisseriaceae family.

Moraxella (Branhamella) catarrhalis, although commonly isolated from sputum in patients with pneumonia, rarely causes bacteremia. Sodium polyanethol sulfonate is commonly added to routine blood culture media to increase the yield of Gram-negative bacilli. This anticoagulant also inhibits the growth of Neisseria meningitidis. We added strains f Moraxella (Branhamella) catarrhalis to routine blood culture media supplemented with 0.03% SPS. No inhibitory effect could be demonstrated. The rare occurrence of bacteremic Moraxella (Branhamella) catarrhalis pneumonia is not due to an inhibitory effect of routine blood culture media.

No description available.