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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Partial purification of Bacillus cereus diarrheagenic enterotoxin

Beebe, Donald Wesley. January 1979 (has links)
Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 60-66).
2

The Effect of Geosmin on the Growth of Bacillus cereus

Barnes, Randall D. 08 1900 (has links)
The purpose of this study was to determine the effect of varying concentrations of geosmin on the growth of Bacillus cereus.
3

Stress response and inorganic poly-phosphate in the Bacillus group bacteria

Atkinson, Deborah Jane January 2010 (has links)
This thesis concentrates on the Bacillus cereus group of organisms and interactions that they may encounter in their natural environment. Inorganic polyphosphate has been identified as an important factor of stress and survival in B. cereus. One of the aims of this project was to create knock out mutants of certain enzymes involved in polyphosphate metabolism in B. anthracis, the etiological agent of anthrax. Unfortunately, even though B. anthracis is very closely related to B. cereus and despite the application of published methods it was not possible to create these B. anthracis knockout mutants. In order to address the importance of inorganic polyphosphate in B. anthracis, a real time RT‐PCR assay was developed to monitor the mRNA levels of these enzymes when the bacterium is faced with harsh nutrient environments Real time RT‐PCR analysis showed that mRNA levels of the metabolizing enzymes were upregulated in low nutrient conditions but that the profiles of gene expression were varied when grown in a chemically defined media. In addition to abiotic stresses such as low nutrients, B. anthracis is also likely to face biotic stress such as predation by amoeba in the soil. Investigations were performed into the outcome of the interaction of B. cereus group bacteria with a model amoeba, Acanthamoeba polyphaga. Amoebae are bacterial predators but can also be utilised as hosts by bacterial symbionts and pathogens, such as Legionella pneumophila. It was theorised that amoebae may provide a host environment similar to that of the professional macrophages, which B. anthracis encounters in mammalian infection. These investigations confirmed that the B. cereus group bacteria demonstrate a range of interactions with amoeba cells, from surface attachment through to intracellular persistence. These studies went on to show that B. cereus, B. thuringiensis and B. anthracis can all be engulfed by amoebae when challenged in their vegetative form and that spores were able to survive, and apparently germinate. Finally these studies have identified a new developmental stage of the B. cereus group bacteria. When grown in static conditions, especially in the presence of amoeba, the bacterial cells cease to septate and large (often motile) continuous hyphae like filaments form. These filaments can be seen to “weave” together to form large “rope” like macrofibre structures which can even become visible by eye. Previously this macrofibre growth has also been seen in B. subtilis, suggesting it may be common to the whole genus. In the light of these findings we speculate that this group of pathogens have evolved complex behaviours to interact with soil amoeba in order to facilitate survival in harsh environmental conditions.
4

Genetic and genomic characterisation of cereolysin O, a hemolysin of Bacillus cereus sensu lato

Michelet, Nathalie C.M. 06 July 2006 (has links)
The Bacillus cereus sensu lato group is composed of six closely-related bacterial species, exhibiting a broad range of virulence activities. B. anthracis causes anthrax to human and mammals and B. thuringiensis is an entomopathogen against Lepidopteran, Coleopteran and Dipteran larvae. B. cereus s.s. and B. weihenstephanensis are opportunistic bacteria, causing gastro-enteritis and more acute diseases in immuno-compromised people. B. mycoides and B. pseudomycoides are generally considered as non-pathogenic. In addition to the specific virulence factors, several generic toxins have been described in the B. cereus s.l. members (phospholipases, enterotoxins, proteases and hemolysins). Among these virulence factors, cereolysin O was first characterised in 1967 by Cowell and Bernheimer, who suggested it to be a member of the cholesterol-dependent cytolysins. This toxin family cause the lysis of cholesterol-containing membranes and their activity, inhibited by oxidising agents, is restored by reducing agents. Moreover, small amount of free cholesterol irreversibly inactivate the toxins. The first part of this thesis gives a description of the hemolytic activities of the different species of the B. cereus s.l. members, with regard to the international ISO norm for the characterisation of B. cereus s.s. in food. One hundred strains were analysed for their hemolytic and lecithinase activities on different blood-containing media, and the results showed that the most sensitive was the sheep erythrocytes-containing medium. The hemolytic activity of B. cereus s.l. is due to at least five hemolysins whose precise roles in pathogenesis are largely unknown. The continuation of this thesis was focused on one of these hemolysins, cereolysin O. PCR, RFLP and Southern blotting analysis pointed out that the clo gene was present and highly conserved in all the strains of the six tested species. The results also indicated that two copies of the clo gene are present in at least 20% of the strains. The last part of this work was to evaluate the hemolytic activity of Clo by knock-out and cloning experiments. The results revealed the importance of cereolysin O in the lysis of human blood as it is not the case on sheep blood.
5

Altering and examining the substrate specificity of phospholipase C from bacillus cereus

Antikainen, Nina Maria 28 August 2008 (has links)
Not available / text
6

Secondary cell wall polysaccharides in Bacillus anthracis and Bacillus cereus strains

Leoff, Christine, January 2009 (has links)
Tübingen, Univ., Diss., 2009.
7

Techniques for isolation and characterization of undegraded RNA during outgrowth of spores of Bacillus cereus

Dickinson, Ellen (Spathelf), January 1969 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
8

Bacillus cereus food poisoning detection and identification of bacillus cereus.

Kim, Hyun Uk, January 1971 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1971. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
9

Altering and examining the substrate specificity of phospholipase C from bacillus cereus

Antikainen, Nina Maria, January 2003 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.
10

The sequence of biochemical events accompanying outgrowth of spores of Bacillus cereus strain T

Steinberg, William. January 1965 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. [97]-109.

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