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Full-Text Articles in Microbiology

Discovery And Characterization Of An Antibiotic From The Soil Bacterium Bacillus Sp., Thomas S. Barber Dec 2010

Discovery And Characterization Of An Antibiotic From The Soil Bacterium Bacillus Sp., Thomas S. Barber

Electronic Theses and Dissertations

Many important antibiotics have become nearly obsolete due to the rise of antibiotic resistant pathogens. Rhodococcus, an actinomycete related to the prolific antibiotic producing genus Streptomyces, harbors over 30 genes for secondary metabolism that could be involved in antibiotic production. Several antibiotics have already been reported for Rhodococcus, suggesting the genus may be a good source for new inhibitory compounds. Fifty four soil bacteria were isolated using enrichment culture techniques (including 37 Rhodococcus) and screened for antibiotic producers. BTHX2, a species of Bacillus was found to have activity against Micrococcus luteus and Rhodococcus erythropolis. BTHX2 …


Modulation Of Alpha-Subunit Visit-Dg Sequence Residues Ser-347, Gly-351 And Thr-349 In The Catalytic Sites Of Escherichia Coli Atp Synthase., Laura Elaine Brudecki Dec 2010

Modulation Of Alpha-Subunit Visit-Dg Sequence Residues Ser-347, Gly-351 And Thr-349 In The Catalytic Sites Of Escherichia Coli Atp Synthase., Laura Elaine Brudecki

Electronic Theses and Dissertations

Binding of inorganic phosphate (Pi) in ATP synthase catalytic sites is a crucial step for the synthesis of adenosine-5'-triphosphate (ATP). ATP is the fundamental means of cellular energy in almost every organism, and in order to gain insight into the regulation of ATP catalysis, critical amino acid residues responsible for binding Pi must be identified. Here, we investigate the role of highly conserved α-subunit VISIT-DG sequence residues αSer-347, αGly-351, and αThr-349 in Pi binding. Mutations αS347A/Q, αG351Q, αT349A/D/R, βR182A, and αT349R/βR182A were generated via site directed mutagenesis. Results from biochemical assays showed that αSer-347 is required …


Isolation Of A Siderophore Produced By Methicillin-Resistant Staphylococcus Aureus Strain H372., Rachel Elizabeth Presswood Aug 2010

Isolation Of A Siderophore Produced By Methicillin-Resistant Staphylococcus Aureus Strain H372., Rachel Elizabeth Presswood

Electronic Theses and Dissertations

Iron is necessary for many cellular processes such as the electron transport chain and gene regulation. However, most iron on earth is found in insoluble iron-hydroxide complexes. In addition, iron is tightly sequestered in the human body by proteins such as transferrin, making it unavailable for pathogens. In order to overcome these limitations bacteria have evolved siderophores. Siderophores are low molecular weight compounds that bind ferric iron with a high affinity. Staphylococcus aureus is an important human pathogen that is known to produce at least four siderophores, and these siderophores contribute to its virulence. S. aureus strain H372 was found …


Inhibition Of Escherichia Coli Atp Synthase By Polyphenols And Their Derivatives., Prasanna Keerthi Dadi May 2010

Inhibition Of Escherichia Coli Atp Synthase By Polyphenols And Their Derivatives., Prasanna Keerthi Dadi

Electronic Theses and Dissertations

We have studied the inhibitory effect of natural and structurally modified polyphenols on Escherichia coli ATP synthase to test (I) if the beneficial dietary effects of polyphenols are related to their inhibitory actions on ATP synthase, (II) if inhibitory effects of polyphenolic compound could be augmented through structural modifications, and (III) if they can act as antimicrobial agent through their actions on ATP synthesis. X-ray crystal structures of polyphenol binding sites suggested that polyphenols bind at a distinct polyphenol binding pocket, at the interface of α,β,γ-subunits. We found that both natural and modified polyphenols inhibit E. coli ATP synthase to …


Isolation And Identification Of The Siderophore "Vicibactin" Produced By Rhizobium Leguminosarum Atcc 14479., William H. Wright Iv May 2010

Isolation And Identification Of The Siderophore "Vicibactin" Produced By Rhizobium Leguminosarum Atcc 14479., William H. Wright Iv

Electronic Theses and Dissertations

Siderophores are small, iron chelating molecules produced by many bacteria to help meet the iron requirements of the cell. Multiple metabolic functions require iron as it serves as a cofactor in many enzymes and cellular processes. However, in the presence of oxygen and at physiologic pH, iron forms insoluble ferric complexes that cause the nutrient to be unavailable to bacterial cells. Siderophores alleviate this limitation by chelating the ferric iron, rendering it soluble and available for uptake. One group of microorganisms known for their ability to produce siderophores is the rhizobia. These bacteria are characterized both by their formation of …