dc.contributor.author	Siddaramappa, Shivakumara Swamy	en
dc.contributor.committeechair	Inzana, Thomas J.	en
dc.contributor.committeemember	Mukhopadhyay, Biswarup	en
dc.contributor.committeemember	Meng, Xiang-Jin	en
dc.contributor.committeemember	Boyle, Stephen M.	en
dc.contributor.committeemember	Tyler, Brett M.	en
dc.contributor.department	Veterinary Medical Sciences	en
dc.date.accessioned	2014-03-14T20:11:26Z	en
dc.date.adate	2007-05-05	en
dc.date.available	2014-03-14T20:11:26Z	en
dc.date.issued	2007-04-09	en
dc.date.rdate	2007-05-05	en
dc.date.sdate	2007-05-02	en
dc.description.abstract	Histophilus somni is a commensal of the mucosal surfaces of respiratory and reproductive tracts of cattle and sheep. However, as an opportunistic pathogen, H. somni can cause diseases such as pneumonia, myocarditis, abortion, arthritis, and meningo-encephalitis. Previously, several virulence factors/mechanisms had been identified in H. somni of which the phase-variable lipooligosaccharide, induction of host cell apoptosis, intraphagocytic survival, and immunoglobulin Fc binding proteins were well characterized. To further understand the biological properties of H. somni, the genomes of pneumonia strain 2336 and preputial strain 129Pt have been sequenced. Using the genome sequence data and comparative analyses with other members of the Pasteurellaceae, putative genes that encode proteases, restriction-modification enzymes, hemagglutinins, glycosyltransferases, kinases, helicases, and adhesins have been identified in H. somni. Most of the H. somni strain-specific genes were found to be associated with prophage-like sequences, plasmids, and/or transposons. Therefore, it is likely that these mobile genetic elements played a significant role in creating genomic diversity and phenotypic variability among strains of H. somni. Functional characterization of H. somni luxS in the genomic context revealed that the gene encodes S-ribosylhomocysteinase that can complement biosynthesis of AI-2 quorum sensing signal molecules in Escherichia coli DH5alpha. It was also found that several pathogenic isolates of H. somni form a prominent biofilm and that luxS as well as phosphorylcholine expression can influence biofilm formation by H. somni. In conclusion, comparative analyses of the genomes and functional characterization of putative genes have shed new light on the versatility and evolution of H. somni.	en
dc.description.degree	Ph. D.	en
dc.identifier.other	etd-05022007-150407	en
dc.identifier.sourceurl	http://scholar.lib.vt.edu/theses/available/etd-05022007-150407/	en
dc.identifier.uri	http://hdl.handle.net/10919/27499	en
dc.publisher	Virginia Tech	en
dc.relation.haspart	03_CHAPTER_III.pdf	en
dc.relation.haspart	00_FRONT_MATTER.pdf	en
dc.relation.haspart	04_CHAPTER_IV.pdf	en
dc.relation.haspart	02_CHAPTER_II.pdf	en
dc.relation.haspart	05_CHAPTER_V.pdf	en
dc.relation.haspart	06_CHAPTER_VI.pdf	en
dc.relation.haspart	01_CHAPTER_I.pdf	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	Bacteriophage	en
dc.subject	Haemophilus	en
dc.subject	Genome	en
dc.subject	Histophilus	en
dc.subject	Plasmid	en
dc.subject	Restriction-Modification	en
dc.subject	LuxS	en
dc.subject	Biofilm	en
dc.title	Comparative and Functional Genomic Studies of Histophilus somni (Haemophilus somnus)	en
dc.type	Dissertation	en
thesis.degree.discipline	Veterinary Medical Sciences	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	doctoral	en
thesis.degree.name	Ph. D.	en

Comparative and Functional Genomic Studies of Histophilus somni (Haemophilus somnus)

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