Uniform TitlePhysiology and molecular ecology of chemolithoautotrophic nitrate reducing bacteria at deep sea hydrothermal vents
NameVoordeckers, James Walter (author), Vetriani, Constantino (chair), Haggblom, Max (internal member), Young, Lily (internal member), Kerkhof, Lee (outside member), Rutgers University, Graduate School - New Brunswick,
SubjectMicrobiology and Molecular Genetics,
Hydrothermal vent ecology,
DescriptionAt hydrothermal vent systems, the ability of microorganisms to use sulfur containing compounds for metabolic purposes has been long established while little is known regarding nitrogen metabolism. The objective of this thesis was to gain a better understanding of how microorganisms are involved in the cycling of nitrogen at deep sea hydrothermal vents through culture dependent and independent methods, isolation of novel nitrate reducing microorganisms, and phylogenetic surveys (16S rRNA gene, citrate lyase (aclA and aclB), and periplasmic nitrate reductase (napA)) of isolates and environmental samples. Sulfide, fluid, and bacterial filament samples from three separate hydrothermal vent sites (Rainbow, Logatchev, and Broken Spur) along the Mid Atlantic Ridge (MAR) and from 9° N on the East Pacific Rise (EPR) were used for isolation and phylogenetic surveys. Several novel autotrophic nitrate ammonifying bacterial strains belonging to the Epsilonproteobacteria were isolated with strain TB2 described as a new species, Caminibacter mediatlanticus. Phylogenetic surveys of the 16S rRNA gene, aclB, and napA showed the dominance of C. mediatlanticus related organisms at the Rainbow hydrothermal vent system indicating that we had successfully isolated an environmentally relevant organism. The environmental survey for napA was the first to be completed for deep sea hydrothermal vents. The phylogenetic survey of napA in reference organisms and environmental samples indicated that there is a wide diversity of Epsilonproteobacterial related sequences present at hydrothermal vents, with the greatest diversity seen within the mesophilic temperature range. It also appears that the periplasmic nitrate reductase gene (napA) is possibly being laterally transferred between members among the Epsilonproteobacteria.
NoteIncludes bibliographical references (p. 102-114).
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.