Rapid expansion of the biodiesel industry has led to a surplus of crude glycerol. This thesis investigates the ability of fungi to utilize crude glycerol as an alternative to conventional carbon substrates for growth and lipid production. Screening revealed that 40 of the 61 isolates tested had increased biomass yield, compared to glucose, when crude glycerol was utilized; 29 of these isolates possessed the ability to completely metabolize 14 g•L-1 of glycerol after 7-14 days. The top four candidates belonged to the genera Galactomyces and Mucor. Overall, Galactomyces sp. proved to be better suited for lipid production. In addition to producing biomass with a high lipid content (up to 45 % w/w), Galactomyces sp. also exhibited high biomass yields (up to 25 g•L-1). The results obtained in this study compare favourably, and in some cases exceed, other literature reported values for biomass and lipid production using glycerol. / CanAdvance and Agriculture and Agri-Food Canada

With additional research on species characteristics and continued work towards cost effective production methods, algae are viewed as a possible alternative biofuel crop to current feedstocks such as corn. Current open pond production methods involve bubbling carbon dioxide (CO_(2)) gas into the media to provide a carbon source for photosynthesis, but this can be very inefficient releasing most CO_(2) back into the atmosphere. This research began by investigating the effect of sodium bicarbonate (NaHCO_(3)) in the growth media as an alternative carbon source to bubbling CO_(2) into the cultures. The second part examined if NaHCO_(3) could act as a lipid trigger in higher (10.0 g/L) concentrations. The microalgae species Dunaliella tertiolecta (Chlorophyta), Mayamaea spp. (Baciallariophyta) and Synechoccocus sp. (Cyanophyta) were grown with 0.0 g/L, 0.5g/L, 1.0 g/L, 2.0 g/L and 5.0 g/L dissolved NaHCO_(3) in modified seawater (f/2) media. To investigate effects of NaHCO_(3) on lipid accumulation, growth media cultures were divided into two ―lipid phase‖ medias containing either 0.0g/L (non-boosted) or 10.0 g/L (boosted) NaHCO_(3) treatments. Culture densities were determined using spectrophotometry, which showed both all three species are able to successfully grow in media ameliorated with these high NaHCO_(3) concentrations. Highest growth phase culture densities occurred in NaHCO_(3) concentrations of 2.0 g/L for D. tertiolecta and Mayamaea spp., and the 5.0 g/L treatment for Synechoccocus sp. Highest growth rates occurred in the 5.0 g/L NaHCO_(3) concentration treatments for D. tertiolecta, Mayamaea spp., and Synechoccocus sp. (0.205 d-1 ±0.010, 0.119 d-1 ±0.004, and 0.372 d-1 ±0.003 respectively). As a lipid accumulation trigger two of the three species (D. tertiolecta and Mayamaea spp) had their highest end day oil indices in a 10.0 g/L treatment. Highest oil indices occurred in boosted 5.0 g/L Dunaliella tertiolecta and 2.0 g/L Mayamaea spp. (13136 ± 895 and 62844 ± 8080 respectively (relative units)). The results obtained indicate NaHCO3 could be used as a photosynthetic carbon source for growth in all three species and a lipid trigger for D. tertiolecta and Mayamaea spp.

No description available.

Purpose: To examine the variables that influence lipid deposition on conventional and silicone hydrogel contact lens materials and to build a physiologically relevant in vitro model of lipid deposition on contact lenses. Methods: Lipid deposition on contact lens materials can lead to discomfort and vision difficulty for lens wearers. Using a variety of radiochemical experiments and two model lipids (cholesterol and phosphatidylcholine), a number of clinically significant parameters that may influence lipid deposition were examined. • The optimization and characterization of a novel artificial tear solution (ATS) was examined (Chapter 3) • Optimization of an extraction system to remove deposited cholesterol and phosphatidylcholine from various contact lens materials (Chapter 4) • The influence of different tear film components on lipid deposition was researched (Chapter 5) • The efficiency of hydrogen peroxide disinfecting solutions to remove deposited lipid from contact lenses was investigated (Chapter 6) • The effect of intermittent air exposure on lipid deposition was examined through the use of a custom built “model blink cell” (Chapter 7) Results: A novel complex ATS designed for in-vial incubations of contact lens materials was developed. This solution was stable and did not adversely affect the physical parameters of the contact lenses incubated within it. An efficient extraction protocol for deposited cholesterol and phosphatidylcholine was optimized based on chloroform and methanol with the addition of water and acetic acid for phosphatidylcholine extraction. Overall, cholesterol and phosphatidylcholine deposition is cumulative over time and found to deposit in greater masses on silicone-containing hydrogels. Cholesterol and phosphatidylcholine deposition is influenced by the composition of the incubation medium and air exposure which occurs during the inter-blink period. Hydrogen peroxide disinfecting solutions were able to remove only marginal amounts of lipid from the contact lenses, with the surfactant containing solution removing more. Conclusion: This thesis has provided hitherto unavailable information on the way in which lipid interacts with conventional and silicone hydrogel contact lens materials and the in vitro model built here can be utilized in various ways in the future to assess other aspects and variables of lipid and protein deposition on a variety of biomaterials.

Physical stress such as the surface roughness of the implants may activate the NFkB signalling pathway in macrophages. This activation is intimately related to the mechanism(s) by which the macrophage interacts with the surface through serum proteins and/or the formation of membrane rafts. This thesis examines the role of surface topography on activation of the NFkB signalling pathway in macrophages. We examined the effect of implant surface topography on activating the NFkB signalling pathway in the RAW 264.7 macrophage cell line. We also examined the effect surface roughness had on the adhesion of the macrophages using the different media. To finish, we observed the effect the different media and the surface roughness had on the morphology of the macrophages by Scanning Electron Microscopy. Activation of the NFkB pathway was surface topography dependent. The Smooth surface showed the highest level of activation followed by the Etched then the SLA. Addition of suboptimal concentrations of LPS mildly enhanced the response by signalling through the Toll receptor. Activation of NFKB occurred in the absence of fetal calf sera, although to a lesser extent. All three surfaces had very few cells with nuclear translocation at the 5 minutes time point with no significant statistical differences between the surfaces. After 30 minutes, translocation reached comparable levels to those surfaces tested with complete medium. Disruption of the lipid rafts affected the triggering and signalling of the NFkB pathway. This inhibitory effect was concentration and time dependent. Smooth surfaces bound more macrophages in the 30 minutes assay. Fetal calf serum appeared to be very critical for adhesion and spreading of the macrophages on the various surfaces examined. Removal of cholesterol did not affect adhesion or spreading on their respective surfaces. We have clearly demonstrated that the lipid rafts along with surface topography play a role in the activation on NFKB. This in-vitro study has demonstrated that surface topography modulated activation of the NFKB signalling pathway in a time-dependent manner. However, at present, it is unclear through which receptor(s) / surface structure the signal pathway is initiated.

Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / Salmonella is a genus of Gram-negative bacteria responsible for food-borne enteritis and systemic fever. Salmonellosis continues to be a serious health burden worldwide. Lipopolysaccharide (LPS) is the dominant lipid component of the outer membrane of Salmonella. LPS is composed of lipid A, an oligosaccharide core, and a polymer of O units known as O antigen. Wzz proteins control the length of O antigen by an unknown mechanism. While O antigen is essential for S. typhimurium virulence, the significance of length regulation by Wzz is not known. This study investigates the pathogenic relevance of the wzz genes in S. typhimurium. In addition to the previously recognised wzz gene (WZZ[subscript]ST), a second gene with this function (WZZ[subscript]fepE) was identified in the S. typhimurium genome. Whereas WZZ[subscript]ST specifies the production of long LPS chains with a modal length of 16-35 O antigen repeat units, WZZ[subscript]fepE conferred very long chains containing> 100 O antigen repeat units. Strains carrying mutations in one or both wzz genes were constructed to investigate the role of wzz genes in virulence. It was found that wzz-controlled regulation of O antigen length was essential for resistance to the bactericidal activity of serum complement, while studies in the mouse model of infection found that wzz genes are essential for full virulence. The wzz double mutant was complemented with heterologous wzz genes from a variety of bacterial sources. Despite variable sequence similarity of the encoded Wzz proteins each was functional in the S. typhimurium host, generating a panel of isogenic O antigen length variants. This panel of variants was used to define a minimum length requirement for complement resistance and identified relationships between O antigen length and complement consumption. Finally, the regulation of O antigen chain length was investigated. It was found that growth either in iron limiting conditions or in serum caused an increased production of LPS with very long O antigen chains (conferred by WZZ[subscript]fepE), resulting in increased complement resistance. The constitutive activation mutation of the phoPQ regulator (Phop) results in an altered O antigen distribution phenotype consistent with down-regulation of wzz genes. However PhoPQ had no effect on production of Wzz[subscript]sT as determined by immunoblotting with an antiWZZ[subscript]ST antiserum. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1152141 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2005

Thesis (Ph.D.) -- Flinders University, School of Medicine, Dept. of Paediatrics and Child Health. / Typescript (bound). Includes bibliographical references (leaves 186-203). Also available online.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2009. / Härtill 3 uppsatser.

Thesis (doctoral)--Universitetet i Lund. / Reprints of journal articles inserted in pocket on back cover.

Universiẗat, Diss., 2006--Würzburg.