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Novel Aspects Of Ultrastructure In Two Species Of Cyanobacteria (Agmenellum Quadruplicatum, Mastigocladus Laminosus), Sandra Anne Nierzwicki-Bauer

Doctoral Dissertations

Novel aspects of morphology and ultrastructure were examined in two species of cyanobacteria. A complete, three-dimensional, ultrastructural reconstruction of the unicellular cyanobacterium Agmenellum quadruplicatum was carried out by means of high-voltage electron microscopy of thick sections and computer-aided reconstruction of serial thin sections. The photosynthetic thylakoid system consisted of 3-6 membrane sheets that traversed and were parallel to the long axis of the cell. These sheets were arranged as an anastomosing network of concentric shells. They coalesced and approached the cytoplasmic membrane at three peripheral loci along the entire length of the cell. The central cytoplasm of the cell was …

Biotransformation And Mutagenicity Of Benzidine, Melissa Lea Rochkind

Doctoral Dissertations

This study was undertaken to investigate whether the priority pollutant benzidine could be biotransformed by bacteria from natural environments and to determine what effect such biotransformation would have on the mutagenicity of the compound. Bacteria were collected from sites of toxic waste dumping and from estuarine, lake, and ocean locations. Sediment and water samples as well as bacterial isolates were incubated in media containing 100 (mu)g ml('-1 14)C(U)-benzidine (specific activity 6.76 mCi/mmol) supplemented with ammonia, phosphate and ferrous iron in aged seawater (salinity 26('o)/oo). Pure cultures were grown overnight in reduced-nutrient broth and washed prior to resuspending in the same …

Regulation Of Macromolecular Synthesis In The Fungus Mucor Racemosus., Joseph Frederick Ross

LSU Historical Dissertations and Theses

Cells of the dimorphic Zygomycetous fungus Mucor racemosus were grown in both batch and continuous culture in order to study the regulation of RNA and protein synthesis as a function of (i) growth rate, (ii) morphogenesis and (iii) nutritional shift-up. In all three cases cells were analyzed for parameters used to calculate (i) cellular ribosome concentration, (ii) percentage of ribosomes active in protein synthesis and (iii) polypeptide chain elongation rate. Cultures subjected to atmospheric or nutritional shifts were additionally pulse labelled or pulse labelled and steady-state labelled with radioactive amino acids and phosphate to measure the rates of synthesis and …

The Regulation Of Gene Expression During The Aerobic Germination Of Mucor Racemosus Sporangiospores., John Edgar Linz

LSU Historical Dissertations and Theses

This study was undertaken to investigate the regulation of gene expression during the aerobic germination of Mucor racemosus sporangiospores. Sucrose density gradient analysis of spore extracts revealed that the percentage of ribosomes associated with mRNA increased from 23% in dormant spores to 85% after 10 min of germination. L-{('14)C}leucine was immediately incorporated at a rapid rate into protein of a leucine auxotroph, whereas {('3)H}uracil or {('32)P}-phosphate were not incorporated into RNA at a significant rate until 20 min after the addition of medium. Newly synthesized RNA did not appear in polysomes until at least 30 min. Polyadenylated RNA, comprising 3.3% …

Evidence For An Outer Membrane - Association Precursor Of The Extracellular Protease Produced By Serratia Marcescens., Laura Robin Liss

LSU Historical Dissertations and Theses

Serratia marcescens LRL781, a gram-negative bacterium, produces an extracellular protease. Evidence is provided for an outer membrane-associated, larger molecular weight, enzymatically inactive precursor of the protease. Antiserum was prepared against the extracellular protease, which was purified from the supernatant fraction of S. marcescens LRL781 cultures. Column adsorption of the antiprotease serum was performed using a slurry of live cells and cellulose. The resulting effluent was serologically inactive against protease preparations and chromium chloride-coupled protease-rabbit erythrocytes. Whole washed cells agglutinated in the presence of the antiserum. Cells were uniformly labeled with ferritin conjugated goat anti-rabbit IgG, indicating that the protease precursor …

The Effect Of Stringent Control On The Production Of Enterotoxin, Tryptophanase, And Beta-Galactosidase By Escherichia Coli In A Recycling Fermentor, Robin Leigh Eifert

Doctoral Dissertations

The recycling fermentor has been shown to be a good tool for studying microorganisms at very slow growth rates. Previous studies have determined that there are three distinct phases of growth based on biomass. Phase 3 has been shown to be initiated by the induction of the stringent response and to be regulated by the levels of guanosine 5'-diphosphate 3'-diphosphate (ppGpp) within the cell. By comparing the growth patterns of three enterotoxigenic Escherichia coli strains to that of E. coli strains of known rel genotypes, the Rel phenotypes of the enterotoxigenic strains were determined.

Both enterotoxin production and secretion in …

The Beta-Fructofuranosidase Of Kluyveromyces Fragilis And Its Use In Inulin Hydrolysis., Wesley Earl Workman

LSU Historical Dissertations and Theses

Inulin, a polyfructan, is found as the reserve carbohydrate in the roots and tubers of various plants. The (beta)-fructofuranosidase (inulase) from the yeast Kluyveromyces fragilis is of interest because of its industrial potential in fructose syrup and alcohol production from inulin containing plants. The enzyme was purified and characterized with respect to its physical and kinetic parameters. The relationship between the enzyme and the yeast cell wall was also investigated. It was found that the inulase of Kluyveromyces fragilis could be immobilized in the yeast cells by glutaraldehyde treatment. Although the exact nature of the immobilization is not fully understood …

Studies On The Structure And Origin Of The Parasporal Inclusion Of Sporulating Bacilli, James Peter Insell

Digitized Theses

The parasporal inclusions of B. thuringiensis subspecies kurstaki, subspecies israelensis, subspecies schwetzova, subspecies alesti, subspecies finitinus, and B. cereus subspecies medusa and subspecies lewinia were purified and analyzed by one-dimensional slab gel electrophoresis. The inclusion of each of the above subspecies was composed of different polypeptides. The protein composition of the inclusions was correlated with the sahpe, structure and toxicity of the inclusion. Four types of inclusions were formed by the seven subspecies studied. Three representative subspecies were chosen for further study.;Two strains of B. cereus and eight subspecies of B. thuringiensis were screened for the presence of plasmid DNA. …

An Analysis Of The Dna Repair-Recombination Functions And The Uvsx-Uvsy Dna Repair Pathway Of Bacteriophage T4, Leonard Paul Wakem

Digitized Theses

Due to the complexity of the T4 uvsX-uvsY DNA repair pathway, we have attempted to define the functions and repair mechanisms involved in the pathway, using several different techniques. The DNA repair-recombination functions of the pathway were analyzed biochemically and genetically to aid in understanding the role of these functions in the cell.;To study the functions of the uvsX and uvsY gene products, DNA intermediates formed after uv-irradiation were extracted from uvsX and uvsY mutant-infected cells and analyzed by sucrose gradient centrifugation. Results of this analysis suggested that the uvsX and uvsY gene products function in a DNA "joining" reaction.;The …

A Comparison Of The Membranes Of Bacillus Megaterium Spores And Cells, Mary Lynn Elmes

Digitized Theses

The biochemical and biophysical properties of Bacillus megaterium KM spore and cell membranes were investigated. Spore inner and outer membranes have been prepared from coat-stripped spores and solubilized spore coat proteins, respectively.;The spore inner and cell membrane phospholipids are similar, except for a decrease in phosphatidylethanolamine in late vegetative state or early sporulation and a decrease in phospholipid content to one-half that of the cell membrane early in spore formation (Stage III). The unique red carotenoid of the inner membrane appears later in B. megaterium KM (Stage V) than in B. megaterium QM B1551 (Stage III-IV). The spore inner and …

Modulation Of The Immunoglobulin-E Response By Dnp-Coupled Bordetella Pertussis, Naeem Akhtar Essani

Digitized Theses

BP vaccine is one of the adjuvants of choice for potentiating the IgE antibody response in rodents. In the present investigations administration of hapten (dinitrophenyl)-coupled Bordetella pertussis organisms (DNP-BP) failed to induce significant levels of anti-DNP IgE antibodies in CBA mice, regardless of the presence of an additional adjuvant {lcub}Al(OH)(,3){rcub}, while high levels of IgG antibodies were produced. The administration of DNP-BP to a number of inbred mouse strains, differing in H-2 genotype showed a clear segregation into low and high IgE responder Phenotypes. The low IgE responder status of CBA mice for DNP-BP, however, was not changed by conventional …