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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.
61

Bactericidal efficacy of wound gauze treated with chitosan nanomaterial hybrids of zinc, silver and copper on common wound bacteria

Shekede, Blessing Tatenda January 2018 (has links)
Thesis (Master of Applied Sciences in Chemistry)--Cape Peninsula University of Technology, 2018. / Maintenance of optimum wound chemistry is important to ensure timely healing of a wound. Bacterial infections impair the process of wound healing by producing toxins that alter the chemical environment in and around the wound. The imbalance in the wound chemistry prolongs healing and opens doors to opportunistic infections. Bacteria have developed resistance to conventional bactericides hence, there is need for search of new bactericides that can control bacteria in and around the wound. Therefore, new chemical or biochemical bactericides, which are not resisted by the bacteria, can be explored to control bacterial life around the wound in a bid to maintain optimum wound healing chemistry. Materials such as chitosan, zinc oxide, copper oxide and silver have showed remarkable potential as both bactericidal and wound healing agents. In this work silver, zinc oxide, and copper oxide nanoparticles (NPs) and their chitosan composites (CH-NPs) were synthesized using the chemical reduction method and simple chelation respectively to produce nanoparticles of Ag, ZnO, and CuO as well as composites of CH-ZnO, CH-Ag, CH-CuO, and CH-ZnO-Ag-CuO. Formation of the NPs was confirmed by the exhibition of characteristic peaks in UV-Visible and Fourier Transform Infrared Resonance (FTIR) spectroscopy as well as X-ray diffraction. The nanoparticles (NPs) had optical and electronic band gaps in the range 1 to 5eV indicating their semi-conductive nature. X-ray diffraction (XRD) investigations depicted the crystalline structures of the NPs to be base-centred, face-centred, and hexagonal for Ag, CuO, and ZnO respectively. Transmission electron microscopy (TEM) studies exhibited spherical, hexagonal, and rod-shaped shapes for silver, copper oxide, zinc oxide NPs respectively. Electrochemical investigations of the pure NPs indicated the existence of both the adsorption and the diffusion controlled electron transfer processes at electrode surfaces as well as fast electron transfer rate as depicted by the charge transfer coefficient and standard rate constant parameter values. FTIR spectra of CH-NPs composites depicted new excitation bands absent in spectra of both chitosan and the NPs. The spectra also indicated the deformation and absence of the amine (-NH2) and hydroxyl bands (-OH) within the CH-NPs composites. UV-Visible spectroscopy investigations of the CH-NPs composites exhibited blue-shifts of the λmax with respect to the NPs. The FTIR and UV-Visible spectra confirmed the existence of bonding between the chitosan and the NPs. The optical band gap energies of all the CH-NPs composites fell within the range of 2.0 to 4.5 eV indicating that the CH-NPs fell in the category of the semi-conducting materials after chelating with the chitosan.
62

Disease resistance related genes co-regulated in bacterial leaf blight near isogenic lines, Xa2, Xa12 and Xa14.

January 2004 (has links)
Shuk-man Chow. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 171-186). / Abstracts in English and Chinese. / Thesis committee --- p.i / Statement --- p.ii / Abstract --- p.iii / Acknowledgement --- p.viii / General abbreviations --- p.x / Abbreviations of chemicals --- p.xi / List of figures --- p.xii / List of Tables --- p.xiii / Table of contents --- p.xv / Chapter 1. --- Literature review / Chapter 1.1. --- General introduction to rice disease --- p.1 / Chapter 1.1.1. --- Pathogenesis of Bacterial Leaf Blight (BLB) --- p.1 / Chapter 1.1.2. --- Pathogenesis of rice blast --- p.2 / Chapter 1.1.3. --- Control of rice diseases --- p.3 / Chapter 1.2. --- Plant defense mechanisms --- p.4 / Chapter 1.2.1. --- Basal resistance in plants --- p.4 / Chapter 1.2.2. --- Wound induced defense response --- p.5 / Chapter 1.2.3. --- Pathogen induced host defense response --- p.6 / Chapter 1.3. --- Structure of R gene products --- p.7 / Chapter 1.4. --- Recognition between R and Avr proteins in rice --- p.8 / Chapter 1.5 --- Current knowledge on Xa resistance and AvrXa avirulence protein --- p.9 / Chapter 1.6 --- Current knowledge on Pi resistance and AvrPi avirulence protein --- p.10 / Chapter 1.7 --- Pathogen induced signal transduction cascade --- p.12 / Chapter 1.7.1. --- R gene mediated signal transduction cascade --- p.12 / Chapter 1.7.2. --- Signal events of G-protein activation --- p.12 / Chapter 1.7.3. --- Signaling events for the accumulation of Ca2+ in cytosol --- p.13 / Chapter 1.7.4. --- Signaling events for oxidative burst --- p.14 / Chapter 1.7.5. --- MAPK cascade in defense signaling --- p.15 / Chapter 1.7.6. --- Transcriptional regulation of disease resistance related genes --- p.16 / Chapter 1.7.7. --- Translational regulation of disease resistance related genes --- p.17 / Chapter 1.8. --- Defense responses and defense related genes --- p.19 / Chapter 1.8.1. --- Pathogenesis related (PR) proteins --- p.20 / Chapter 1.8.2. --- Phytoalexins --- p.21 / Chapter 1.9. --- Disease resistance related genes common between rice blast and BLB resistance --- p.22 / Chapter 1.10. --- SA induced signal transduction pathway in rice --- p.23 / Chapter 1.11. --- Important tools facilitating the identification of disease resistance related genes from BLB resistant rice lines --- p.24 / Chapter 1.12. --- Hypothesis --- p.26 / Chapter 1.13. --- Project objective --- p.26 / Chapter 2. --- Materials and Methods --- p.27 / Chapter 2.1. --- Plant Materials --- p.27 / Chapter 2.2. --- Pathogen Inoculation --- p.27 / Chapter 2.3. --- RNA extraction --- p.29 / Chapter 2.4. --- Denaturing gel electrophoresis --- p.29 / Chapter 2.5. --- Subtraction libraries construction --- p.30 / Chapter 2.5.1. --- Cloning of disease resistance related genes --- p.32 / Chapter 2.5.1.1. --- pBluescript II KS (+) T-vector preparation --- p.32 / Chapter 2.5.1.2. --- Ligation --- p.32 / Chapter 2.5.1.3. --- Transformation --- p.32 / Chapter 2.5.1.4. --- Colony picking --- p.33 / Chapter 2.5.1.5. --- PCR amplification of DNA inserts --- p.33 / Chapter 2.5.1.6. --- Purification of PCR products --- p.34 / Chapter 2.6. --- Gene chips printing --- p.34 / Chapter 2.7. --- Probes synthesis and gene chips hybridization --- p.35 / Chapter 2.8. --- Standard-RNAs synthesis --- p.35 / Chapter 2.9. --- Data collection and analysis --- p.36 / Chapter 2.10. --- Sequencing --- p.36 / Chapter 2.11. --- cDNA synthesis --- p.37 / Chapter 2.12. --- RT-PCR --- p.38 / Chapter 2.13. --- DNA gel electrophoresis --- p.39 / Chapter 3. --- Results --- p.58 / Chapter 3.1. --- Construction of BLB gene chips --- p.58 / Chapter 3.1.1. --- Preparation of cDNA clones for gene chips construction --- p.58 / Chapter 3.1.2. --- Purification of PCR products on microtiter plate --- p.59 / Chapter 3.1.3. --- Gene chips construction --- p.59 / Chapter 3.1.4. --- DNA immobilization --- p.62 / Chapter 3.1.5. --- Probe synthesis --- p.62 / Chapter 3.1.6. --- Gene chip analysis --- p.65 / Chapter 3.1.6.1. --- Scanning --- p.65 / Chapter 3.1.6.2. --- Data analysis --- p.65 / Chapter 3.2. --- "Identification of disease resistance related genes commonly regulated by Xa2, Xal2 and Xal4 BLB resistance loci" --- p.70 / Chapter 3.2.1. --- "Signal perception, transduction and regulatory elements" --- p.71 / Chapter 3.2.1.1. --- Proteins involved in reversible phosphorylation cascade --- p.71 / Chapter 3.2.1.2. --- Proteins potentiate signal transduction through specific protein-protein interaction --- p.72 / Chapter 3.2.1.3. --- Other signal transduction components --- p.73 / Chapter 3.2.2. --- Transcriptional and translational regulatory elements --- p.74 / Chapter 3.2.2.1. --- Proteins involved in transcriptional regulation --- p.74 / Chapter 3.2.2.2. --- Proteins involved in post-transcriptional regulation --- p.75 / Chapter 3.2.2.3. --- Proteins involved in translational regulation --- p.76 / Chapter 3.2.3. --- "Oxidative burst, stress, apoptotic related genes" --- p.77 / Chapter 3.2.3.1. --- Stress related proteins --- p.77 / Chapter 3.2.3.2. --- Proteins involved in induction of oxidative burst --- p.78 / Chapter 3.2.3.3. --- PR proteins --- p.79 / Chapter 3.2.3.4. --- Proteolysis related proteins --- p.79 / Chapter 3.2.4. --- Cell maintenance and metabolic genes --- p.80 / Chapter 3.2.4.1. --- Antioxidant --- p.80 / Chapter 3.2.4.2. --- Metabolic genes --- p.81 / Chapter 3.2.4.3. --- Molecular chaperone --- p.82 / Chapter 3.2.4.4. --- Cell cycle regulators --- p.82 / Chapter 3.2.4.5. --- Cell wall maintenance --- p.83 / Chapter 3.2.4.6. --- Proteins involved in protein transport --- p.83 / Chapter 3.2.5. --- Unclassified/others --- p.84 / Chapter 3.3. --- Expression analysis of disease resistance related genes --- p.88 / Chapter 4. --- Discussion --- p.141 / Chapter 4.1. --- Differential expression of disease resistance candidates --- p.141 / Chapter 4.2. --- Disease resistance signal transduction components --- p.143 / Chapter 4.2.1. --- Reversible phosphorylation cascade --- p.143 / Chapter 4.2.2. --- Signal transduction potentiated by protein-protein interaction --- p.144 / Chapter 4.3. --- Other signaling molecules --- p.145 / Chapter 4.3.1. --- PRL1-interacting factor G --- p.145 / Chapter 4.3.2. --- Vacuolar-type H+-ATPasen subunit G --- p.146 / Chapter 4.4. --- Regulation of expression of disease resistance candidates --- p.146 / Chapter 4.4.1. --- Transcriptional regulation of disease resistance related genes --- p.146 / Chapter 4.4.1.1. --- G-box binding protein --- p.147 / Chapter 4.4.1.2. --- MYB TF --- p.147 / Chapter 4.4.2. --- Post-transcriptional modification of disease resistance candidates --- p.148 / Chapter 4.4.2.1. --- RNA splicing factor --- p.148 / Chapter 4.4.2.2. --- Glycine rich RNA binding proteins --- p.149 / Chapter 4.4.3. --- Translational regulation of disease resistance related genes --- p.149 / Chapter 4.5. --- Induction of oxidative burst --- p.150 / Chapter 4.6. --- PR proteins --- p.151 / Chapter 4.7. --- Cell maintenance --- p.152 / Chapter 4.7.1. --- Protein folding --- p.152 / Chapter 4.7.2. --- Protein degradation --- p.153 / Chapter 4.7.3. --- ROS scavenging --- p.154 / Chapter 4.7.4. --- Regulation of cell cycle --- p.154 / Chapter 4.8. --- "Confirmation and profiling of disease resistance related candidates commonly regulated in Xa2, Xal2 and Xal4 BLB resistance NILs at different time points" --- p.155 / Chapter 4.8.1. --- Basal resistance related genes --- p.156 / Chapter 4.8.2. --- General disease resistance related genes --- p.161 / Chapter 4.8.3. --- Pathogen responsive genes --- p.164 / Chapter 4.8.4. --- Prediction of novel genes functions --- p.168 / Chapter 4.9. --- Future prospect --- p.169 / Chapter 4.10. --- Conclusion --- p.169 / References --- p.171 / Appendix --- p.187
63

The potential role and mechanism of an unconventional GTPase and its interacting partner in rice defense response.

January 2009 (has links)
Xue, Yan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 95-102). / Abstract also in Chinese. / Thesis committe --- p.2 / Statement --- p.3 / Abstract --- p.4 / Acknowledgement --- p.8 / General abbreviations --- p.10 / Abbreviations of chemicals --- p.13 / List of figures --- p.15 / List of tables --- p.16 / Table of contents --- p.17 / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- Impact of bacterial blight on rice production --- p.25 / Chapter 1.2 --- The plant immune system --- p.25 / Chapter 1.2.1 --- Preformed resistance --- p.25 / Chapter 1.2.2 --- PAMP triggered immunity (PTI) --- p.26 / Chapter 1.2.3 --- Effecter triggered immunity (ETI) --- p.27 / Chapter 1.2.3.1 --- R genes --- p.27 / Chapter 1.2.3.2 --- Hypersensitive responses (HR) --- p.27 / Chapter 1.2.3.3 --- Systemic acquired resistance (SAR) --- p.28 / Chapter 1.2.3.3.1 --- Salicylic acid is required for SAR establishment --- p.28 / Chapter 1.2.3.3.2 --- Involvement of lipid-based molecules in SAR signaling --- p.28 / Chapter 1.2.3.3.3 --- NPR1: the master regulator of SAR --- p.29 / Chapter 1.2.3.3.4 --- Expression of pathogenesis related (PR) genes --- p.29 / Chapter 1.2.4 --- Interaction between SA and JA --- p.29 / Chapter 1.2.5 --- Other important signaling components in plant defense responses --- p.30 / Chapter 1.2.5.1 --- G proteins --- p.30 / Chapter 1.2.5.2 --- G proteins in defense responses --- p.30 / Chapter 1.3 --- OsGAPl is a C2 (protein kinase C conserved region 2) domain harboring GTPase activating protein --- p.32 / Chapter 1.4 --- OsYchFl is a GTPase and an interacting partner of OsGAPl --- p.32 / Chapter 1.5 --- Hypothesis and objectives of this research --- p.33 / Chapter Chapter 2 --- materials and methods / Chapter 2.1 --- Materials --- p.35 / Chapter 2.1.1 --- Chemicals and reagents --- p.39 / Chapter 2.1.2 --- Commercial kits --- p.40 / Chapter 2.1.3 --- Primers used --- p.41 / Chapter 2.1.4 --- Equipment and facilities used: --- p.47 / Chapter 2.1.5 --- "Buffer, solution, gel and medium:" --- p.47 / Chapter 2.2 --- Methods: --- p.51 / Chapter 2.2.1 --- Culture of bacterial strains --- p.51 / Chapter 2.2.2 --- Composition of medium used in this work for cultivating bacterial strains: --- p.51 / Chapter 2.2.3 --- Plant growth and treatment --- p.52 / Chapter 2.2.3.1 --- Surface sterilization of Arabidopsis thaliana seeds --- p.52 / Chapter 2.2.3.2 --- Seed germination and Arabidopsis plant growth --- p.52 / Chapter 2.2.4 --- Generation of transgenic Arabidopsis --- p.53 / Chapter 2.2.4.1 --- Agrobacterium-mediated Arabidopsis transformation --- p.53 / Chapter 2.2.5 --- Pathogen inoculation test --- p.54 / Chapter 2.2.6 --- Molecular cloning --- p.54 / Chapter 2.2.6.1 --- DNA sequencing: --- p.55 / Chapter 2.2.6.2 --- Transformation of E. coli strains: --- p.55 / Chapter 2.2.6.3 --- Transformation of Agrobacteria by electroporation --- p.55 / Chapter 2.2.7 --- DNA and RNA extraction --- p.56 / Chapter 2.2.7.1 --- Plasmid DNA extraction from bacterial cells --- p.56 / Chapter 2.2.7.2 --- Genomic DNA extraction from plant tissues --- p.56 / Chapter 2.2.7.3 --- RNA extraction from plant tissues --- p.56 / Chapter 2.2.8 --- Northern blot --- p.57 / Chapter 2.2.9 --- Subcellular localization studies --- p.58 / Chapter 2.2.9.1 --- Transformation of tobacco BY-2 cells --- p.58 / Chapter 2.2.9.2 --- Maintenance of transgenic tobacco BY-2 cells --- p.59 / Chapter 2.2.9.3 --- Confocal microscopy --- p.59 / Chapter 2.2.9.4 --- Electron microscopy --- p.59 / Chapter 2.2.10 --- Bimolecular fluorescence complementation studies (BiFC) --- p.60 / Chapter 2.2.10.1 --- Construct making --- p.61 / Chapter 2.2.10.2 --- Preparation of rice protoplasts --- p.61 / Chapter 2.2.10.3 --- PEG-mediated transfection --- p.62 / Chapter 2.2.10.4 --- Detection of protein-protein interaction --- p.62 / Chapter Chapter 3 --- Results / Chapter 3.1 --- OsGAPl interacts with OsYchFl in vivo --- p.63 / Chapter 3.1.1 --- Construction of vectors for BiFC transient assay in rice protoplasts --- p.64 / Chapter 3.1.2 --- BiFC assay in rice protoplasts revealed in vivo interaction between the OsGAPl and the OsYchFl proteins --- p.66 / Chapter 3.2.1 --- Subcellular localization of OsGAPl --- p.68 / Chapter 3.2.2 --- Localization of OsGAPl and OsYchFl in rice leaves revealed by electron microscopy --- p.70 / Chapter 3.3 --- Functional characterization of OsYchFl / Chapter 3.3.1 --- Characterization of Arabidopsis YchF1 knockdown mutant --- p.75 / Chapter 3.3.2 --- Complementation of AtYchF1 knockdown Arabidopsis --- p.77 / Chapter 3.3.3.1 --- Pathogen inoculation test --- p.80 / Chapter Chapter 4 --- Discussion / Chapter 4.1 --- Significance of the project --- p.85 / Chapter 4.2 --- In vivo interaction between OsGAPl and OsYchFl --- p.86 / Chapter 4.3 --- OsGAPl is located either inside the cytosol or on the plasma membrane in transgenic tobacco BY-2 cells --- p.87 / Chapter 4.4 --- Study of wounding effect on the subcellular localization of OsGAPl and OsYchFl at whole plant level by EM --- p.88 / Chapter 4.5 --- OsYchFl functions as a negative regulator of defense responses in A.thaliana --- p.90 / Chapter 4.6 --- Conclusion --- p.92 / References --- p.95 / Appendix --- p.103
64

Immune response and protection against Streptococcus pyogenes after vaccination with Lactococcus lactis that expresses conserved region of M6 protein

Mannam, Praveen 04 June 2003 (has links)
Most pathogens gain access to their host through mucosal surfaces. It is therefore desirable to develop mucosal vaccines that elicit an immune response to prevent this crucial first step in infection. Current mucosal vaccines are live attenuated strains of pathogens. More recent efforts have focused on the use of recombinant non-pathogenic gram-positive bacteria as live vaccine delivery vectors. Here I have tested the potential of Lactococcus lactis to be used as a vaccine vector. A recombinant strain of L. lactis has been constructed which expresses and displays on its surface the C repeat region (CRR) of the M6 protein of Streptococcus pyogenes. I show that nasal vaccination of mice with this strain elicited strong salivary IgA and serum lgG response. These responses protected mice against a nasal challenge with S. pyogenes. Subcutaneous vaccination with the same strain of L. lactis produced a strong serum lgG response, but no salivary lgA response. Subcutaneous vaccination did not protect the mice against nasal infections when the mice were challenged with S. pyogenes. The immune response and protection afforded by concomitant vaccination by both nasal and subcutaneous routes were better that that seen in nasal vaccination alone. This study shows that an effective vaccine against S. pyogenes is possible using L. lactis as a vaccine vector. It also opens up the potential of L. lactis to be used in the development of vaccines to other mucosal infections. / Graduation date: 2004
65

The effect of exposure to antibiotics on incidence and spontaneous clearance of childhood Helicobacter pylori infection.

Broussard, Cheryl Schroedter. Goodman, Karen J., Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 68-11, Section: B, page: 7281. Adviser: Karen J. Goodman. Includes bibliographical references.
66

The relationship of Drosophila nigrospiracula and Ervinia carnegieana to the bacterial necrosis of Carnegiea gigantea

Graf, Penelope Ann, 1941- January 1965 (has links)
No description available.
67

Biological and molecular characterization of South African bacteriophages infective against Staphylococcus aureus subsp. aureus Rosenbach 1884, casual agent of bovine mastitis.

Basdew, Iona Hershna. 27 November 2013 (has links)
Bacteriophage therapy has been exploited for the control of bacterial diseases in fauna, flora and humans. However, the advent of antibiotic therapy lead to a cessation of most phage research. Recently, the problem of antibiotic resistance has rendered many commonly used antibiotics ineffective, thereby renewing interest in phage therapy as an alternative source of control. This is particularly relevant in the case of bovine mastitis, an inflammatory disease of bovine mammary glands, caused by strains such as Staphylococcus aureus subsp. aureus Rosenbach 1884. Antibiotic resistance (primarily towards penicillin and methicillin) by staphylococcal strains causing mastitis is regularly reported. Phage therapy can provide a stable, effective and affordable system of mastitis control with little to no deleterious effect on the surrounding environment or the affected animal itself. Several studies have delved into the field of biocontrol of bovine mastitis using phages. Results are variable. While some phage-based products have been commercialized for the treatment of S. aureus-associated infections in humans, no products have yet been formulated specifically for the strains responsible for bovine mastitis. If the reliability of phage therapy can be resolved, then phages may become a primary form of control for bovine mastitis and other bacterial diseases. This study investigated the presence of S. aureus and its phages in a dairy environment, as well as the lytic ability of phage isolates against antibiotic-resistant strains of mastitic S. aureus. The primary goals of the thesis were to review the available literature on bovine mastitis and its associated control, and then to link this information to the use of phages as potential control agents for the disease, to conduct in vitro bioassays on the selected phages, to conduct phage sensitivity assays to assess phage activity against different chemical and environmental stresses, to morphologically classify the selected phages using transmission electron microscopy, to characterize the phage proteins using one-dimensional electrophoresis, and lastly, to characterize phage genomes, using both electrophoresis as well as full genome sequencing. Twenty-eight phages were isolated and screened against four strains of S. aureus. Only six phages showed potential for further testing, based on their wide host range, high titres and common growth requirements. Optimal growth conditions for the host S. aureus strain was 37°C for 12hr. This allowed for optimal phage replication. At an optimal titre of between 6.2x10⁷ to 2.9x10⁸ pfu.mlˉ¹(at 10ˉ⁵ dilution of phage stock), these phages were able to reduce live bacterial cell counts by 64-95%. In addition, all six phages showed pathogenicity towards another 18 S. aureus strains that were isolated from different milk-producing regions during a farm survey. These six phages were named Sabp-P1, Sabp-P2, Sabp-P3, Sabp-P4, Sabp-P5 and Sabp-P6. Sensitivity bioassays, towards simulated environmental and formulation stresses were conducted on six identified phages. Phages Sabp-P1, Sabp-P2 and Sabp-P3 showed the most stable replication rates at increasing temperatures (45-70°C), in comparison to phages Sabp-P4, Sabp-P5 and Sabp-P6. The effect of temperature on storage of phages showed that 4ºC was the minimum temperature at which phages could be stored without a significant reduction in their lytic and replication abilities. Furthermore, all phages showed varying levels of sensitivity to chloroform exposure, with Sabp-P5 exhibiting the highest level of reduction in activity (74.23%) in comparison to the other phages. All six phages showed optimal lytic ability at pH 6.0-7.0 and reduced activity at any pH above or below pH 6.0-7.0. Exposure of phages to varying glycerol concentrations (5-100%) produced variable results. All six phages were most stable at a glycerol concentration of 10-15%. Three of the six isolated phages, Sabp-P1, Sabp-P2 and Sabp-P3, performed optimally during the in vitro assays and were used for the remainder of the study. Morphological classification of phages Sabp-P1, Sabp-P2 and Sabp-P3 was carried out using transmission electron microscopy. All three phages appeared structurally similar. Each possessed an icosahedral head separated from a striated, contractile tail region by a constricted neck region. The head capsules ranged in diameter between 90-110nm with the tail length ranging from 150-200nm in the non-contractile state and 100-130nm in the contractile state. Rigid tail fibres were also visible below the striated tail. The major steps in the virus replicative cycle were also documented as electron micrographs. Ultra-thin sections through phage plaques were prepared through a modification of traditional methods to speed up the process, with no negative effects on sample integrity. The major steps that were captured in the phage replicative cycle were (1) attachment to host cells, (2) replication within host cells, and, (3) release from cells. Overall results suggested that all three phages are strains from the order Caudovirales and are part of the Myoviridae family. A wealth of information can be derived about an organism based on analysis of its proteomic data. In the current study, one-dimensional electrophoretic methods, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and ultra-thin layer isoelectric focusing (UTLIEF), were used to analyse the proteins of three phages, Sabp-P1, Sabp-P2 and Sabp-P3, in order to determine whether these strains differed from each other. SDS-PAGE analysis produced unique protein profiles for each phage, with band fragments ranging in size from 8.86-171.66kDa. Combined similarity matrices showed an 84.62% similarity between Sabp-P1 and Sabp-P2 and a 73.33% similarity between Sabp-P1 and Sabp-P3. Sabp-P2 showed a 69.23% similarity to Sabp-P3. UTLIEF analysis showed protein isoelectric charges in the range of pI 4.21-8.13, for all three phages. The isoelectric profiles for each phage were distinct from each other. A combined similarity matrix of both SDS-PAGE and UTLIEF data showed an 80.00% similarity between phages Sabp-P1 and Sabp-P2, and a 68.29% similarity between Sabp-P1 and Sabp-P3. Sabp-P2 showed a 70.59% similarity to Sabp-P3. Although the current results are based on putative protein fragments analysis, it can be confirmed that phages Sabp-P1, Sabp-P2 and Sabp-P3 are three distinct phages. This was further confirmed through genomic characterization of the three staphylococcal phages, Sabp-P1, Sabp-P2 and Sabp-P3, using restriction fragment length analysis and whole genome sequencing. Results showed that the genomes of phages Sabp-P1, Sabp-P2 and Sabp-P3 were all different from each other. Phages Sabp-P1 and Sabp-P3 showed sequence homology to a particular form of Pseudomonas phages, called "giant" phages. Phage Sabp-P3 showed sequence homology to a Clostridium perfringens phage. Major phage functional proteins (the tail tape measure protein, virion structural proteins, head morphogenesis proteins, and capsid proteins) were identified in all three phages. However, although the level of sequence similarity between the screened phages and those already found on the databases, enabled preliminary classification of the phages into the order Caudovirales, family Myoviridae, the level of homology was not sufficient enough to assign each phage to a particular type species. These results suggest that phage Sabp-P1 might be a new species of phage within the Myoviridae family. One longer-term objective of the study is to carry out complete assembly and annotation of all the contigs for each phage. This will provide definitive conclusions in terms of phage relatedness and classification. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.
68

Characterisation of cell wall proteins, virulence factor maturation and invasive disease trigger of Group A streptococcus

Cole, Jason Nicklaus. January 2006 (has links)
Thesis (Ph.D.)--University of Wollongong, School of Biological Sciences. / Typescript. Includes bibliographical references: leaf 269-331.
69

Control of bacterial pathogens associated with mastitis in dairy cows with natural antimicrobial peptides produced by lactic acid bacteria /

Pieterse, Reneé. January 2008 (has links)
Thesis (MSc)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.
70

Obstructive jaundice an experimental study on host defense failure and intestinal bacterial translocation in the rat /

Ding, Jin Wen. January 1993 (has links)
Thesis (doctoral)--Lund University, 1993. / Added t.p. with thesis statement inserted.

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