Bacteriology Commons^™

Response Of A Nitrifying Biofilm To Copper, Denise Moldroski Mott

Masters Theses

In pure cultures of Nitrosomonas, copper is known to cause a stimulation of nitrification at low levels (≤ 0.03 mg Cu⁺²/1) and an inhibition affect at higher levels (≥ 0.05 mg Cu⁺²/1). Nitrifying activated sludges are much more tolerant of copper showing only 75% inhibition at 150mg Cu⁺²/1. The purpose of this paper was to determine the copper sensitivity of a nitrifying biofilm grown in a continuous flow trickling filter system.

A continuous flow trickling filter system was built using limestone chips for the biofilm substrate. The biofilm was established from secondary effluent. …

Fecal Coliform Membrane Filtration Recovery Techniques, Pamela Rose Rinebold

Masters Theses

Researchers over the years have been trying to improve recovery techniques for fecal coliform bacteria. Improved techniques would provide better estimates of the number of fecal coliform bacteria as well as better estimates of fecal contamination with potential pathogenicity of food and water.

Stressed, but viable, fecal coliform bacteria if placed under the appropiate conditions, can recover, thus presenting the possibility of inadequate disinfection. Chlorine sanitization, as done in potable and wastewater treatment, is one such method of stressing bacteria.

Techniques of recovery were studied using presumably unstressed and chlorine stressed samples. Phase one of this study was the comparison …

A Comparison Of The Acidic Extracellular Polysaccharides From Rhizobium Trifolii Mutants Affected In Trifolium Repens Root Hair Curling, Brian Andrew Hanley

Masters Theses

The compositions and sugar linkages of the acidic extracellular polysaccharide (EPS) from several Rhizobium trifolii mutants were compared. These mutants were derived from a wild type Rhizobium trifolii, ANU843, and are unable to cause normal root hair curling, Hac-, or nodulate clover, Nod-. Three of the mutants contain a Tn5 insertion in a 5.3 kb BglII fragment of the symbiotic plasmid (pSym). A fourth mutant is missing the pSym, which includes much of the 5.3 kb BglII fragment, both of these deletions result in Hac-Nod- phenotypes. When the 5.3 kb BglII fragment is cloned (pRT150) and reinserted into the …

Characterization Of The Lipopolysaccharides (Lps) From Four Transposon Generated Symbiotic Mutants Of Rhizobium Trifolii, Robert G. Shatters Jr.

Masters Theses

The LPSs from four symbiotic mutants of R. trifolii were isolated and characterized. The mutants were obtained from Dr. Barry Rolfe of The Australian National University. Three mutants have Tn5 insertions in the "nod" regions of the symbiotic plasmid. The fourth has a 30 kb deletion. This deletion includes the majority of the "nod" regions. All mutants fail to nodulate clover and fail to induce markedly curled root hairs, i.e. they are hac-nod-. The LPSs were purified as described by Carlson et al. 1978.⁷ The polysaccharide portion of the LPSs was purified by treating the LPSs in 1% HAc …

Comparison Of Surface Polysaccharides Of R. Leguminosarum Anu57 (Exo-1), R. Leg. Anu57(Pbr1an) (Nod+, Nif-), And R. Leg. Anu57(Pjb5j1) (Nod+, Nif-), Frank G. Hustmyer

Masters Theses

Extracellular polysaccharides (EPS) and lipopolysaccharides (LPS) are suspected to be involved in the legume/Rhizobium symbiotic process. Polysaccharide compositions from the EPS, LPS, capsular polysaccharide (CPS), and small polysaccharide (SmPS) were compared between Rhizobium leguminosarum ANU57 (parent, Exo^-1) and two mutants R. leg. ANU57(pBR1AN) (nod⁺, nif^-) and R. leg. ANU57(pJB5J1) (nod⁺, nif^-) both containing a Sym (symbiotic) plasmid insertion. R. leg. ANU57(pBR1AN) and R. leg. ANU57(pJB5J1) are nod⁺ on clover and peas, respectively. The nod⁺ mutants produce larger amounts of EPS and decreased amounts of LPS compared to …

Siderocapsa Major-- Fact Or Artifact?, Ray W. Swanson

Masters Theses

The validity of the genus Siderocapsa, a group of unicellular iron-depositing bacteria, has been a subject of debate for many years. Lack of photomicroscopic and cultural studies has kept this group in taxonomic obscurity. Bacteria were collected from the Campus pond, Eastern Illinois University, Charleston, Illinois, by a submerged slide/coverslip technique. These bacteria were identified as Siderocapsa major according to the description of Molisch (1909). Scanning electron microscopy of Siderocapsa major microcolonies has shown cells (0.5 by 1.15 μm), in a clear central well (2-6 μm), surrounded by an amorphous material which accumulates with the age of the colony. …

Pesticide Effects In A Simulated Soil Ecosystem, Raymond J. Samp

Masters Theses

The screening of pesticides to determine which were most inhibitory to bacteria was accomplished by testing the effects of 10 pesticides on 9 different organisms using the disk assay method. Results showed that Gram positive bacteria were more sensitive to all pesticides tested than were the Gram negative bacteria. In addition, the hormone herbicides were found to be the most inhibitory to these bacteria and 2,4-D (2,4-dichlorophenoxyacetic acid), a hormone herbicide, was chosen for subsequent in vivo studies.

A soil perfusion apparatus was used to determine the effects of 2,4-D in a typical soil ecosystem. Bacterial plate counts and nutrient …

Studies On Muropeptide Amino Acids Of Rhizobium Japonicum, Mohammed Alauddin

Masters Theses

The isolation of Rhizobium japonicum cell walls was performed by ultrasonication and the enzymatic digestion with DNase, RNase and pronase separately. Crude cell walls were washed with M NaCl and 5% SDS and were isolated by 20,000 g centrifugation. Muropeptide amino acids were freed by hydrolysis at 121C for 10 minutes in 6N HCl.

Detection of Rhizobium japonicum murein layer amino acids was done by 2-dimensional instant thin layer chromatography on silica gel plates. The solvents found most favorable, were n-butanol: acetic acid: water and n-propanol: 34% ammonium hydroxide. Amino acid spots were developed by spraying ninhydrin on the chromatograms, …

Morphological And Physiological Effects Of 2,4-D On Gram-Negative And Gram-Positive Bacteria, John H. Rupnow

Masters Theses

Manometric, spectrophotometric, photomicrographic and quantitative biochemical techniques were employed to determine the morphological and physiological effects of 2,4-D on Gram-positive and Gram-negative bacteria.

The growth and motility of Gram-positive bacteria appeared to be more adversely affected than the growth and motility of Gram-negative species. The terminal oxidation, lysis, and chain length of both Gram-positive and Gram-negative bacteria did not appear to be affected by the concentrations used. The average cell size of both Gram-positive and Gram-negative bacteria was observed to increase after exposure to 1000 ppm 2,4-D. The normal leakage of amino acid and ultraviolet light absorbing cell constituents appeared …

Lysis Of The Rhizobiaceae, Craig Richard Baumrucker

Masters Theses

The following members of the Rhizobiaceae were tested for their lytic response to various treatments: Agrobacterium tumefaciens, Chromobacterium violaceum, Rhizobium phaseoli, Rhizobium trifolii, Rhizobium lupini, and Rhizobium japonicum. Lysis was observed in spent growth media and as a function of saline concentration, pH, buffer composition, disodium (ethylenedinitrilo) tetraacetate (EDTA) concentration, and lysozyme.

Cells were harvested by centrifugation, washed, and resuspended in various treatment solutions. The lytic response was followed spectrophotometrically.

The different responses of the six cultures was applied to a summation of reclassification proposals evolved through modern taxonomic techniques such as DNA homology …