Theses and Dissertations at Montana State University (MSU)
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Item Evaluation of methanotrophic activity and growth in a methanotrophic-heterotrophic co-culture(Montana State University - Bozeman, College of Engineering, 2021) Kilic, Ayse Bengisu; Chairperson, Graduate Committee: Ellen G. Lauchnor; Erika J. Espinosa-Ortiz, Brent M. Peyton and Ellen Lauchnor were co-authors of the article, 'Methane-based bioreactor configurations in value-added product development: a review' submitted to the journal 'Journal of bioscience and bioengineering' which is contained within this thesis.; Erika J. Espinosa-Ortiz, Brent M. Peyton and Ellen Lauchnor were co-authors of the article, 'Evaluation of methanotrophic activity and growth in a methanotrophic-heterotrophic co-culture' submitted to the journal 'Engineering in life sciences' which is contained within this thesis.Methane is a potent greenhouse gas (GHG) and accounts for 20-30% of the GHG emissions globally. In nature, methane is utilized as a sole carbon and energy source by a group of bacteria referred to as methanotrophs. Methanotrophs have been reported to have the ability to form close associations with other microorganisms such as heterotrophic bacteria in the environment. Therefore, understanding methanotrophic activity and growth in a microbial consortium with heterotrophic bacteria is of interest from an environmental and biotechnology perspective. In this study, a methanotroph; Methylocystis sp. NLS7 and a heterotrophic bacterium, Pseudomonas chlororaphis, were co-cultivated in a methane-fed bioreactor with a dialysis membrane device used to separate the species physically. It was hypothesized that the co-culture would exhibit enhanced methanotrophic activity and microbial growth of NLS7 in NLS7- P. chlororaphis co-culture. The methane-oxidation rate and microbial growth rate of NLS7 were evaluated as a functional response variable to the presence of P. chlororaphis. In addition, the effects of NLS7 growth were evaluated on the growth of P. chlororaphis. Our findings indicated that the presence of P. chlororaphis does not have any beneficial effects on Methylocystis sp. NLS7 activity and growth. However, the growth of P. chlororaphis in the co-culture with solely methane as a carbon source indicated that P. chlororaphis is likely gaining carbon and energy from by-products of methane oxidation by Methylocystis sp. NLS7 since P. chlororaphis could not utilize methane as a carbon and energy source. The results of this study give us an important insight into the activity and the growth of methanotrophic consortia in methane-driven ecosystem.Item The factors affecting the distribution and dynamics of bacterioplankton biomass and productivity in Taylor Valley Lakes, Antarctica(Montana State University - Bozeman, College of Letters & Science, 1999) Takacs, Cristina D.Item Image analysis of novel biomaterials : effectiveness at inhibiting bacterial colonization with unique polymer coatings and/or the controlled release of ciprofloxacin(Montana State University - Bozeman, College of Engineering, 1998) Hendricks, Sara KirstenItem The influence of growth rate and cell concentration on bacterial attachment to surfaces in a continuous flow system(Montana State University - Bozeman, College of Engineering, 1983) Nelson, Christopher HenryItem Characterization of initial events of bacterial colonization at solid-water interfaces using image analysis(Montana State University - Bozeman, College of Engineering, 1990) Mueller, Robert FranzItem Colonization of a smooth surface by Pseudomanas aeruginosa : image analysis methods(Montana State University - Bozeman, College of Engineering, 1986) Escher, Andreas RainerItem Cellular reproduction and extracellular polymer formation in the development of biofilms(Montana State University - Bozeman, College of Engineering, 1983) Trulear, Michael GeraldItem Novel compounds inhibiting HIV infection, breast cancer metastasis, and bacterial growth(Montana State University - Bozeman, College of Letters & Science, 2012) Shepard, Joyce Brewer; Chairperson, Graduate Committee: Martin Teintze; Royce A. Wilkinson, Jean R. Starkey and Martin Teintze were co-authors of the article, 'Novel compounds containing multiple guanide groups that inhibit breast cancer metastases' in the journal 'International journal for cancer research' which is contained within this thesis.; Royce A. Wilkinson was a main author, and Cassidy Cooper, Sarah K. Walton, Amanda R. Radke, Robert L. Watkins, Thomas J. Wright, Elizabeth Erikson, Mohamed E. Labib, Jovanka M. Voyich, and Martin Teintze were co-authors of the article, 'Broad-spectrum antibacterial activity in novel compounds containing multiple phenylguanide or biguanide groups' in the journal 'Journal of antimicrobial chemotherapy' which is contained within this thesis.We synthesized novel guanide, biguanide, phenylguanide, and naphthyguanide derived compounds on linear, branched, and dendrimer backbones that are effective inhibitors of HIV infection, breast cancer metastasis, and bacterial growth. HIV utilizes CXCR4 as a co-receptor for cellular entry. Blocking CXCR4 inhibits infection with X4 strains of the virus. Initial competition assays demonstrated that some of the phenylguanide compounds bound to CXCR4 with high affinity. The derivatives with high CXCR4 affinity inhibited X4 viral infection, but did not inhibit R5 or X4R5 viruses. Importantly, many cancers overexpress CXCR4, including breast cancer. CXCR4 activation leads to cellular chemotaxis, angiogenesis, and cell survival, all of which promote cancer survival and proliferation. Compounds with high CXCR4 affinity were evaluated for inhibition of breast cancer metastasis. In vitro toxicity of all the derivatives was determined, followed by in vitro migration inhibition. Three derivatives with the best selectivity indexes for CXCR4 were examined in an in vivo lung colony metastasis assay. Spermidine trisphenylguanide (SI = 1785) was evaluated at 50 micrometers, 200 micrometers, and 300 micrometers and showed increasing inhibition of lung metastases (P = 0.34, 0.3, 0.02, respectively). Spermidine bis-2-naphthylguanide (SI = 1230) and spermine tris-2-naphthylguanide (SI = 191) were evaluated at 100 micrometers and showed significant reduction of lung metastases (P = 0.1 and 0.04, respectively). The topical antiseptic biguanide chlorhexidine, is structurally similar to our derivatives. So, the derivatives were tested for antimicrobial activity against drug susceptible and resistant pathogenic Enterococcus, Staphylococcus, Acinetobacter, and Pseudomonas strains. THAM trisphenylguanide, DNT2300 biguanide and phenylguanide, and DNT2200 phenylguanide demonstrated broad spectrum bacteriocidal activity similar to chlorhexidine. Preliminary in vivo studies on mice treated with THAM trisphenylguanide either immediately after methicillin resistant Staphylococcus aureus (MRSA) infection or an hour post MRSA infection showed significant reductions in bacterial burden in the intraperitoneal cavity, heart and kidney in the immediate treatment group and slight reductions of bacterial burden in the one hour treatment group. This data shows the potential for treatment of MRSA infections with the tested compounds. Thus, different subsets of the novel guanide compounds discussed here can inhibit HIV infection, breast cancer metastasis, and bacterial growth.Item Diversity, productivity, and physiology of microorganisms in the stream-moat-lake transition of Lake Bonney, Antarctica(Montana State University - Bozeman, College of Agriculture, 2007) Moore, Joel Grant; Chairperson, Graduate Committee: John C. Priscu.Air temperatures exceeding 0°C in Taylor Valley, Antarctica 17-25 degree days each summer and constant solar irradiance melt glacial and lake ice to from liquid water moats at the edges of permanently ice-covered lakes. Moats are fed by glacial streams and interact with comparatively large volumes of ice-covered lake water. This study investigated stream influence on moat chemistry and microbial biomass, productivity and diversity in the moat of East Lake Bonney (ELB) and compared the moat to the ice-covered portion of ELB. Stream inflow was a source of dissolved ions, inorganic carbon (DIC) inorganic nitrogen (DIN), and soluble reactive phosphorus (SRP) to the moat. SRP was rapidly removed in the moat near the stream inflow. Melted ELB ice and biological uptake reduced concentrations of DIN and DIC, resulting in a negative relationship to the inflow. Stream nutrients were correlated with high chlorophyll a and bacterial biomass near the inflow, were positively correlated with bacterial diversity, and negatively correlated with phytoplankton diversity. Correlations between nutrient availability and microbial biomass suggest resource limitation with respect to DIN and SRP, and infer dependence of heterotrophic bacterioplankton on primary productivity.