Matching Items (6)
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- All Subjects: Phage
- All Subjects: Water resources management
- Creators: Abbaszadegan, Morteza
Description
Research in microbial biofuels has dramatically increased over the last decade. The bulk of this research has focused on increasing the production yields of cyanobacteria and algal cells and improving extraction processes. However, there has been little to no research on the potential impact of viruses on the yields of these phototrophic microbes for biofuel production. Viruses have the potential to significantly reduce microbial populations and limit their growth rates. It is therefore important to understand how viruses affect phototrophic microbes and the prevalence of these viruses in the environment. For this study, phototrophic microbes were grown in glass bioreactors, under continuous light and aeration. Detection and quantification of viruses of both environmental and laboratory microbial strains were measured through the use of a plaque assay. Plates were incubated at 25º C under continuous direct florescent light. Several environmental samples were taken from Tempe Town Lake (Tempe, AZ) and all the samples tested positive for viruses. Virus free phototrophic microbes were obtained from plaque assay plates by using a sterile loop to scoop up a virus free portion of the microbial lawn and transferred into a new bioreactor. Isolated cells were confirmed virus free through subsequent plaque assays. Viruses were detected from the bench scale bioreactors of Cyanobacteria Synechocystis PCC 6803 and the environmental samples. Viruses were consistently present through subsequent passage in fresh cultures; demonstrating viral contamination can be a chronic problem. In addition TEM was performed to examine presence or viral attachment to cyanobacterial cells and to characterize viral particles morphology. Electron micrographs obtained confirmed viral attachment and that the viruses detected were all of a similar size and shape. Particle sizes were measured to be approximately 50-60 nm. Cell reduction was observed as a decrease in optical density, with a transition from a dark green to a yellow green color for the cultures. Phototrophic microbial viruses were demonstrated to persist in the natural environment and to cause a reduction in algal populations in the bioreactors. Therefore it is likely that viruses could have a significant impact on microbial biofuel production by limiting the yields of production ponds.
ContributorsKraft, Kyle (Author) / Abbaszadegan, Morteza (Thesis advisor) / Alum, Absar (Committee member) / Fox, Peter (Committee member) / Arizona State University (Publisher)
Created2014
Description
This project aims to address the current protocol regarding the diagnosis and treatment of traumatic brain injury (TBI) in medical industries around the world. Although there are various methods used to qualitatively determine if TBI has occurred to a patient, this study attempts to aid in the creation of a system for quantitative measurement of TBI and its relative magnitude. Through a method of artificial evolution/selection called phage display, an antibody that binds highly specifically to a post-TBI upregulated brain chondroitin sulfate proteoglycan called neurocan has been identified. As TG1 Escheria Coli bacteria were infected with KM13 helper phage and M13 filamentous phage in conjunction, monovalent display of antibody fragments (ScFv) was performed. The ScFv bind directly to the neurocan and from screening, phage that produced ScFv's with higher affinity and specificity to neurocan were separated and purified. Future research aims to improve the ScFv characteristics through increased screening toward neurocan. The identification of a highly specific antibody could lead to improved targeting of neurocan post-TBI in-vivo, aiding researchers in quantitatively defining TBI by visualizing its magnitude.
ContributorsSeelig, Timothy Scott (Author) / Stabenfeldt, Sarah (Thesis director) / Ankeny, Casey (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2015-05
Description
The diagnosis of bacterial infections based on phage multiplication has the potential for profound clinical implications, particularly for antibiotic-resistant strains and the slow-growing Mycobacterium tuberculosis. The possibility of hastening the diagnosis of antibiotic-resistant mycobacterial infections was accomplished via the study of Mycobacterium smegmatis, a generally non-pathogenic, comparatively fast growing microorganism to M. tuberculosis. These proof-of-concept studies established that after transduction of M. smegmatis cells with bacteriophages, MALDI-TOF MS could be used to detect increased amounts of phage proteins. Recording the growth of M. smegmatis over an 8-hour period, starting with very low OD600 measurements, simulated bacterial loads in clinical settings. For the purposes of MALDI-TOF MS, the procedure for the most effective lethal exposure for M. smegmatis was determined to be a 1-hour incubation in a 95°C water bath. Successful precipitation of the lytic mycobacteriophages D29 and Giles was performed using chloroform and methanol and overlaid with 1-2 μL of α-cyano-4-hydoxycinnaminic acid, which allowed for more distinct and repeatable MALDI-TOF MS spectra. Phage D29 was found to produce an m/z peak at 18.477 kDa, which may have indicated a 2+-charged ion of the 34.8 kDa minor tail protein. The Giles proteins that were identified with MALDI-TOF MS have not been directly compared to protein values reported in the scientific literature. However, the MALDI-TOF MS spectra suggested that distinct peaks existed between M. smegmatis mc2155 and mycobacteriophages, indicating that successful infection with lytic phage and replication thereafter may have occurred. The distinct peaks between M. smegmatis and the phage can be used as indicators of the presence of mycobacteria. At this point, the limits of detection of each phage must be elucidated in order for MALDI-TOF MS spectra to be successfully implemented as a mechanism to rapidly detect antibiotic-resistant mycobacteria.
ContributorsBarrett, Rachael Lauren (Author) / Haydel, Shelley (Thesis director) / Sandrin, Todd (Committee member) / Maarsingh, Jason (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
This study was designed to provide insight into microbial transport kinetics which might be applied to bioremediation technology development and prevention of groundwater susceptibility to pathogen contamination. Several pilot-scale experiments were conducted in a saturated, 2 dimensional, packed porous media tank to investigate the transport of Escherichia coli bacteria, P22 bacteriophage, and a visual tracer and draw comparisons and/or conclusions. A constructed tank was packed with an approximate 3,700 cubic inches (in3) of a fine grained, homogeneous, chemically inert sand which allowed for a controlled system. Sampling ports were located at 5, 15, 25, and 25 vertical inches from the base of the 39 inch saturated zone and were used to assess the transport of the selected microorganisms. Approximately 105 cells of E. coli or P22 were injected into the tank and allowed to move through the media at approximately 10.02 inches per day. Samples were collected intermittently after injection based off of an estimated sampling schedule established from the visual tracer.
The results suggest that bacteriophages pass through soil faster and with greater recovery than bacteria. P22 in the tank reservoir experienced approximately 1 log reduction after 36 hours. After 85 hours, P22 was still detected in the reservoir after experiencing a 2 log reduction from the start of the experiment. E. coli either did not reach the outlet or died before sampling, while P22 was able to be recovered. Bacterial breakthrough curves were produced for the microbial indicators and illustrate the peak concentrations found for each sampling port. For E. coli, concentrations at the 5 inch port peaked at a maximum of 5170 CFU/mL, and eventually at the 25 inch port at a maximum of 90 CFU/mL. It is presumed that E. coli might have experienced significant filtration, straining and attachment, while P22 might have experienced little adsorption and instead was transported rapidly in long distances and was able to survive for the duration of the experiment.
The results suggest that bacteriophages pass through soil faster and with greater recovery than bacteria. P22 in the tank reservoir experienced approximately 1 log reduction after 36 hours. After 85 hours, P22 was still detected in the reservoir after experiencing a 2 log reduction from the start of the experiment. E. coli either did not reach the outlet or died before sampling, while P22 was able to be recovered. Bacterial breakthrough curves were produced for the microbial indicators and illustrate the peak concentrations found for each sampling port. For E. coli, concentrations at the 5 inch port peaked at a maximum of 5170 CFU/mL, and eventually at the 25 inch port at a maximum of 90 CFU/mL. It is presumed that E. coli might have experienced significant filtration, straining and attachment, while P22 might have experienced little adsorption and instead was transported rapidly in long distances and was able to survive for the duration of the experiment.
ContributorsAcosta, Jazlyn Cauren (Author) / Abbaszadegan, Morteza (Thesis advisor) / Dahlen, Paul (Committee member) / Fox, Peter (Committee member) / Arizona State University (Publisher)
Created2017
Description
This dissertation investigates the mechanisms that lead to fouling, as well as how an understanding of how these mechanisms can be leveraged to mitigate fouling.
To limit fouling on feed spacers, various coatings were applied. The results showed silver-coated biocidal spacers outperformed other spacers by all measures. The control polypropylene spacers performed in-line with, or better than, the other coatings. Polypropylene’s relative anti-adhesiveness is due to its surface free energy (SFE; 30.0 +/- 2.8 mN/m), which, according to previously generated models, is near the ideal SFE for resisting adhesion of bacteria and organics (~25 mN/m).
Previous research has indicated that electrochemical surfaces can be used to remove biofilms. To better elucidate the conditions and kinetics of biofilm removal, optical coherence tomography microscopy was used to visualize the biofouling and subsequent cleaning of the surface. The 50.0 mA cm-2 and 87.5 mA cm-2 current densities proved most effective in removing the biofilm. The 50.0 mA cm-2 condition offers the best balance between performance and energy use for anodic operation.
To test the potential to incorporate electrochemical coatings into infrastructure, membranes were coated with carbon nanotubes (CNTs), rendering the membranes electrochemically active. These membranes were biofouled and subsequently cleaned via electrochemical reactions. P. aeruginosa was given 72h to develop a biofilm on the CNT-coated membranes in a synthetic medium simulating desalination brines. Cathodic reactions, which generate H2 gas, produce vigorous bubbling at a current density of 12.5 mA cm-2 and higher, leading to a rapid and complete displacement of the biofilm from the CNT-functionalized membrane surface. In comparison, anodic reactions were unable to disperse the biofilms from the surface at similar current densities.
The scaling behavior of a nanophotonics-enabled solar membrane distillation (NESMD) system was investigated. The results showed the NESMD system to be resistant to scaling. The system operated without any decline in flux up to concentrations 6x higher than the initial salt concentration (8,439 mg/L), whereas in traditional membrane distillation (MD), flux essentially stopped at a salt concentration factor of 2x. Microscope and analytical analyses showed more fouling on the membranes from the MD system.
To limit fouling on feed spacers, various coatings were applied. The results showed silver-coated biocidal spacers outperformed other spacers by all measures. The control polypropylene spacers performed in-line with, or better than, the other coatings. Polypropylene’s relative anti-adhesiveness is due to its surface free energy (SFE; 30.0 +/- 2.8 mN/m), which, according to previously generated models, is near the ideal SFE for resisting adhesion of bacteria and organics (~25 mN/m).
Previous research has indicated that electrochemical surfaces can be used to remove biofilms. To better elucidate the conditions and kinetics of biofilm removal, optical coherence tomography microscopy was used to visualize the biofouling and subsequent cleaning of the surface. The 50.0 mA cm-2 and 87.5 mA cm-2 current densities proved most effective in removing the biofilm. The 50.0 mA cm-2 condition offers the best balance between performance and energy use for anodic operation.
To test the potential to incorporate electrochemical coatings into infrastructure, membranes were coated with carbon nanotubes (CNTs), rendering the membranes electrochemically active. These membranes were biofouled and subsequently cleaned via electrochemical reactions. P. aeruginosa was given 72h to develop a biofilm on the CNT-coated membranes in a synthetic medium simulating desalination brines. Cathodic reactions, which generate H2 gas, produce vigorous bubbling at a current density of 12.5 mA cm-2 and higher, leading to a rapid and complete displacement of the biofilm from the CNT-functionalized membrane surface. In comparison, anodic reactions were unable to disperse the biofilms from the surface at similar current densities.
The scaling behavior of a nanophotonics-enabled solar membrane distillation (NESMD) system was investigated. The results showed the NESMD system to be resistant to scaling. The system operated without any decline in flux up to concentrations 6x higher than the initial salt concentration (8,439 mg/L), whereas in traditional membrane distillation (MD), flux essentially stopped at a salt concentration factor of 2x. Microscope and analytical analyses showed more fouling on the membranes from the MD system.
ContributorsRice, Douglas, Ph.D (Author) / Perreault, Francois (Thesis advisor) / Abbaszadegan, Morteza (Committee member) / Fox, Peter (Committee member) / Lind-Thomas, Mary Laura (Committee member) / Arizona State University (Publisher)
Created2019
Description
Nitrogen removal and energy reduction in wastewater treatment are shared goals. Approaches to achieve those goals include the techniques of shortcut nitrogen removal utilizing nitrite shunt, biocatalyst, nitritation, deammonification, and simultaneous nitrification-denitrification. The practice of those techniques is newer in the industry of wastewater treatment but continues to develop, along with the understanding of the biological and chemical activities that drive those processes. The kinetics and stoichiometry of traditional and shortcut nitrogen removal reactions are generally well understood to date. However, the thermodynamics of those processes are complex and deserve additional research to better understand the dominant factors that drive cell synthesis. Additionally, the implementation of nitrogen shortcut techniques can reduce the footprint of wastewater treatment processes that implement nitrogen removal by approximately 5 percent and can reduce operating costs by between 12 and 26 percent annually. Combined, nitrogen shortcut techniques can contribute to significant reduction in the long-term cost to operate, due to lower energy and consumable requirements, fast reaction times resulting in shorter solids retention times, and improvement efficiency in nitrogen removal from wastewater. This dissertation explores and defines the dominant factors that contribute to the success of efficiencies in traditional and shortcut nitrogen removal techniques, focusing on the natural microbiological processes. The culmination of these efforts was used to develop decision matrices to promote consideration of nitrogen shortcut techniques by practitioners during conceptual planning and design of wastewater treatment facilities.
ContributorsTack, Frederick Henry (Author) / Fox, Peter (Thesis advisor) / Krajmalnik-Brown, Rosa (Committee member) / Abbaszadegan, Morteza (Committee member) / Alum, Absar (Committee member) / Arizona State University (Publisher)
Created2021