Thesis Title

Physiological And Phylogenetic Characterization Of Three Psychrophilic Marine Bacteria

Date of Graduation

Spring 2004


Master of Science in Biology



Committee Chair

John Steiert


Three bacterial strains capable of growing below 10°C were characterized physically and systematically. These strains were originally isolated from Antarctic sea ice. Two of the isolates (strains 101-W3 and 75-O2) were classified as psychotrophs and one was classified as a true psychrophile (strain 23-P) based on temperature growth profiles. Microscopic and Gram stain analysis showed that strain 101-W3 is Gram-positive with pleomorphic morphology; strain75-O2 is a Gram-positive cocci; and strain 23-P is a Gram-negative rod. All three strains produced pigmentation, were non-motile, were catalase and oxidase positive, and did not grow anaerobically. The strains were tested for their ability to utilize different carbon sources and optimal growth profiles were generated for temperature, salinity and pH. Phylogenitic characterization was performed by sequencing the 16S rRNA gene for each of the strains. BLAST analysis indicates that strain 101-W3 is a member of the Arthrobacter genus, 75-O2 is related to the Planoccus genus, and 23-P is a Polaribacter genus, and 23-P is a Polaribacter species.


Antarctica, Arthrobacter, Planococcus, pleomorphic, pigmentation, Polaribacter, psychrophile

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© Brinnon L. Morrison