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Characterization Of A New Freshwater Methanogen, Methanogenium Wolfei Sp. Nov., Theodore B. Moore

Dissertations and Theses

A recently isolated freshwater methanogenium species, Methanogenium wolfei, is characterized. Cells were irregular cocci, measuring 1.5 to 2.0 micrometers in diameter. No motility was observed, but 1 to 2 flagella per cell were observed after staining with Gray's Flagella Stain. Colonies formed by this species were small, shiny, and green-brown in color. Formate or hydrogen plus carbon dioxide served as substrates for growth. The optimal temperature for growth was found to be 45 degrees centigrade with minimal growth below 30 degrees centigrade and above 55 degrees centigrade. The optimal pH for growth was determined to be 6.8. Optimal growth was …

Partial Purification And Characterization Of F₄₂₀-Dependent Nadp Reductase From Methanobrevibacter Smithii Strain De1, Scott D. Sheridan

Dissertations and Theses

The F₄₂₀-dependent NADP reductase of Methanobrevibacter smithii has been partially purified employing a combination of affinity chromatography with Blue Sepharose (Cl-6B) and molecular sieve chromatography with Sephacryl S-200, The enzyme, which requires reduced F₄₂₀ as an electron donor, has been purified over 145 fold with a recovery of 6%. A molecular weight of 120,00 for the native enzyme was determined by Sephacryl S-200 chromatography. A subunit molecular weight of 28,200 was determined by SDS-PAGE, indicating that the native enzyme is a tetramer. The optimal temperature for enzymatic activity was found to be 45°C, with a pH optimum …

The Absence Of Extrachromosomal Dna In Methanogenic Bacteria, Nancy Ann Kurkinen

Dissertations and Theses

Five species of methanogenic bacteria were analyzed for the presence of plasmid DNA. Several procedures for the detection and isolation of covalently closed circular plasmid DNA were modified for use with the methanogens.

Enzyme Reactions Using Ureidosuccinate As A Substrate During Pyrimidine Biosynthesis And Degradation In Cl. Oroticum, Penny Amy

Dissertations and Theses

Cells of Clostridium oroticum, an anaerobic bacterium, were grown on orotate as a carbon and energy source. Ureidosuccinase, an inducible enzyme in the pathway for pyrimidine degradation has been shown to convert ureidosuccinate to aspartate, CO₂ and NH₃ as reported by Liebenmm and Kornberg (7). Aspartate and CO₂ were formed in approximately a 1:1 ratio from ureidosuccinase activity.

Ureidosuccinase was found to be a Mn+² requiring enzyme with a pH optimum of approximately pH 6.5. Enzyme activity is labile to O₂, temperature, pH, dilution and high ionic strength. The optimum conditions for storage …