Bacteriology Commons^™

Tools For Quantifying Bacterial Motility Using Digital Holographic Microscopy As Applied To Studying The Simulated Microgravity Environment, Jacqueline Marie Acres

Dissertations and Theses

Digital holographic microcopy (DHM) is a label-free technique that has gained attention in recent years as a tool for volumetric imaging. One application of DHM is for the study of microbial motility with the advantage being that organisms may freely move within their environment. Images created from DHM are in the form of holograms. Holograms are time recordings showing XY information with the Z information contained within. Z information can be retrieved from the holograms directly through a variety of numerical techniques or through reconstruction. Datasets generated from DHM are large and processing remains a challenging task. Here, we show …

Symbiosis In Archaea: Functional And Phylogenetic Diversity Of Marine And Terrestrial Nanoarchaeota And Their Hosts, Emily Joyce St. John

Dissertations and Theses

The Nanoarchaeota are an enigmatic lineage of Archaea found in deep-sea hydrothermal vents and geothermal springs across the globe. These small (~100-400 nm) hyperthermophiles live ectosymbiotically with diverse hosts from the Crenarchaeota. Despite their broad distribution in high-temperature environments, very few Nanoarchaeota have been successfully isolated in co-culture with their hosts and nanoarchaeote genomes are poorly represented in public databases. However, the Nanoarchaeota provide unique insights into the structure and function of symbiosis in the archaeal domain. This study describes novel nanoarchaeotes from multiple geothermal habitats, using a combination of direct cultivation techniques and genomic analysis. A new nanoarchaeote …

Gene Expression In Two Cyanobacteria, Freshwater Synechococcus Sp. Pcc 7942 And Oceanic Synechococcus Sp. Wh 7803, In Response To Ammonium, Nitrate Or Iron, Abbas Sadeghi

Dissertations and Theses

The transcriptional response of freshwater Synechococcus sp. PCC 7942 and oceanic Synechococcus sp. WH 7803 to ammonium, nitrate or iron was studied in single or multiple factor limited cultures. Both strains showed maximum production of NiR mRNA when grown in nitrate-containing media. When grown in ammonium-containing medium, they did not show any signal for NiR mRNA synthesis. The influence on the transcription of NiR mRNA by iron as sole limiting nutrient was also evaluated. Iron increased the NiR mRNA whether or not the positive effect of nitrate was already present. The hybridization signal of mRNA for the large subunit of …

The Morphology, Physiology, And Fine Structure Of A Toluene-Oxidizing Strain Of Pseudomonas Putida, Barry Clayton Anderson

Dissertations and Theses

The role of microorganisms in the degradation of xenobiotics in the environment is well established. Bacteria from the genus Pseudomonas are particularly well adapted to the degradation of hydrocarbons, aromatics, and numerous other natural and introduced substrates. We have isolated a strain of Pseudomonas putida, designated PC2P15, that uses toluene, phenol, benzene, and a number of other substrates as its sole sources of carbon and energy.

Effects Of Conalbumin Bound Iron On The Growth Of Salmonella Paratyphi B And Salmonella Thompson, John Nicholas Mason

Dissertations and Theses

I have investigated the possibility that specific conalbumin (ovotransferrin) iron saturation levels enable less virulent strains of Salmonella to become more virulent. Iron starved cells of two pathogenic Salmonella strains, S. paratyphi B var. java and S. thompson, were cultured in iron limited media at 3 different iron conalbumin saturation levels. Results indicate that strains differ significantly at both low and high iron saturation conalbumin. These differences depict a growth advantage for S. paratyphi B which correlates with reports by the Centers for Disease Control that S. paratyphi B was 3 times more frequent in blood isolates than S. …

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 …

Characterization Of Gram-Positive Bacterial Isolates From Burn Victims, Trisha A. Hannan

Dissertations and Theses

Streptococcus and Staphylococcus were collected from patients hospitalized at the Oregon Burn Center, Emanuel Hospital, Portland, Oregon, between October 27, 1980 and January 1, 1981. Forty-five isolates of Staphylococcus and twenty-one isolates of Streptococcus, Lancefield Group D, were included in the investigation.

The objectives of the investigation were: (i) to identify to the species level all isolates, (ii) to determine their susceptibility to antimicrobial agents, (iii) to test the organisms. over time for increasing resistance to silver, (iv) to determine, if present, a bacterium harbored within the burn unit (nosocomial bacterium), and (v) to determine any recognizable pattern of successive …

Plasmid-Mediated Resistance To Arsenite And Arsenate In Escherichia Coli, Thomas Patrick Trezona

Dissertations and Theses

Bacterial strains resistant to arsenite, arsenate (or both) are readily isolated from nature. The resistance, in many cases, can be shown to be determined by conjugal plasmids. The mechanisms by which these plasmids confer resistance to arsenic compounds are entirely unknown. This study was undertaken to shed light on some of the physiological and genetic aspects of this resistance using plasmid-bearing strains of Escherichia coli which are highly resistant to both arsenite and arsenate. Most studies were carried out using E. coli J53 (R773) or the plasmid-free strain J53.

Euryhelmis Cotti N. Sp. (Trematoda: Heterophyidae) With Observations On Its Life Cycle, Michael Joseph Simon

Dissertations and Theses

Fish of the genus Cottus were found infected with heterophyid metacercariae. Laboratory animals were infected with the metacercariae, and adult heterophid trematodes were recovered. These flukes were found to represent an undescribed species of the genus Euryhelmis. Various streams in the Willamette Valley and coastal areas were sampled for infected Cottus sp. Snails of the genera Oxytrema and Fluminicola were collected. Several possible definitive hosts were examined. A partial review of the subfamily Apophallinae and a complete review of the genus Euryhelmis are presented. Euryhelmis cotti n. sp. is placed in the subfamily Apophallinae, and its life cycle …

Repression Of Β-Galactosidase Synthesis In Escherichia Coli By Salicylates, Joan Carlyn Olson

Dissertations and Theses

Salicylic acid, and to a lesser extent aspirin, have been shown to repress β-galactosidase synthesis in Escherichia coli. The repression is not due to decreased inducer uptake, nor does it result from competition with inducer for repressor. Dinitrophenol does not exert similar effects on β-galactosidase synthesis. Cyclic adenosine 31, 51-monophosphate partially relieves the repression. The extent or the relief by cyclic adenosine monophosphate seems to depend on the concentration of salicylic acid. This indicates there may be direct interaction between the actions of cyclic adenosine monophosphate and salicylic acid in E. coli cells.

The Effect Of Antibiotics On Thermophilic Blue-Green Algae, Erleen Blanche Christenson

Dissertations and Theses

The nature of the action of penicillin on the cell walls of bacteria is reviewed. The composition of bacterial cell walls is compared to cell walls of blue-green algae.

The test organisms used were thermophilic: Anacystis nidulans grew optimally at 35⁰C, whereas Synechococcus lividus grew best at 45⁰ C. Growth was recorded by reading optical densities.

Cells of these two thermophilic blue-green algae were treated with varying dosages of penicillin and streptomycin. Penicillin inhibited growth of Anacystis nidulans and Synechococcus lividus in concentrations of 3.0 µg/ml and 0.03 µg/ml respectively. However, when 0.3 µg/ml of penicillin was added to Anacystis …