Life Sciences Commons^™

Clpxp-Regulated Proteins Suppress Requirement For Reca In Dam Mutants Of Escherichia Coli K-12, Amie Savakis

Masters Theses

Double strand breaks (DSB) are a common source of DNA damage in both prokaryotes and eukaryotes. If they are not repaired or are repaired incorrectly, they can lead to cell death (bacteria) or cancer (humans). In Escherichia coli, repair of DSB are typically accomplished via homologous recombination and mediated by RecA. This repair pathway, among others, is associated with activation of the SOS response. DNA adenine methyltransferase (dam) mutants have an increased number of DSB and, therefore, are notorious for being RecA-dependent for viability. Here, we show that the synthetic lethality of Δdam/ΔrecA is suppressed when clpP is removed, suggesting …

Characterization Of Pinitol Catabolism In Sinorhizobium Meliloti And Its Role In Nodule Occupancy, Angela Irene Kennedy-Mendez

Masters Theses

Sinorhizobium meliloti, which is the nitrogen fixing symbiont of Medicago sativa (alfalfa), was used to test the hypothesis that D-chiro-inositol is an intermediate of pinitol catabolism and that pinitol catabolism plays a role in S. melilot s ability to compete for nodule occupancy. An analytical method, involving gas chromatography and mass spectrometry (GCMS), was developed to detect and separate pinitol and D-chiro-inositol. The S. meliloti wild type, and three isogenic mutant strains (idhA, mocD, and mocE) were grown in minimal medium with pinitol and pinitol plus glycerol. The S. meliloti wild type can utilize pinitol as a sole carbon source, …

Biotransformation Of Oxo-Bile Acids Derivatives By Human Gut Bacteria, Laina Sallam

Masters Theses

Bile acids are one group of steroids that can be metabolically transformed by human gut anaerobes. One of these transformations is the conversion of primary bile acids to secondary bile acids by 7α-dehydroxylating gut bacteria such as Clostridium scindens, Clostridium hylemonae, and Clostridium hiranonis. These anaerobes metabolize bile acid derivatives via 3α- and 7α-hydroxysteroid dehydrogenases (HSDH). Studies to date have not reported if these organisms are capable of converting 12-oxolithocholic acid (12-oxoLCA) to deoxycholic acid (DCA). The emphasis of this study was to determine the ability of C. scindens ATCC 35704, C. hiranonis DSM 13275, and C. …

Distiphallus Morphology And Its Role In Copulation Dynamics In Anastrepha Suspensa (Loew), Taylor J. Inboden

Masters Theses

Anastrepha suspensa (Diptera; Tephritidae) is an agricultural pest species

causing severe economic damage and is controlled, in part, by applying knowledge

of this species' reproduction (e.g., disrupting fertile copulations by SIT). During

copulation, males transfer sperm as well as protein rich fluids through an aedeagus

and distiphallus, which females then store in three spermathecae and one ventral

receptacle. Within the female reproductive tract, the ventral receptacle and the

three spermathecae are strategically separated from each other. I hypothesized

males' ability to direct sperm transfer within the female reproductive tract is

through the structures found in the distiphallus. Utilizing scanning electron …

Resolution Of The Nutritional Requirements And Metabolic Profile Of Clostridium Scindens Atcc 35704, A Major Bile Acid-Dehydroxylating Anaerobe In The Human Gut, Rachana Shrestha

Masters Theses

Bile acids (cholate and chenodeoxycholate) are synthesized from cholesterol in the human liver, and secreted in small intestine for food digestion. However, a portion of these primary bile acids is converted in the colon to toxic secondary bile acids, deoxycholate and lithocholate. Secondary bile acid formation is the result of 7α-dehydroxylating anaerobes, and one of the key players in this conversion is Clostridium scindens. Interestingly, little is known about the basic physiology and nutrition of C. scindens. Therefore, the goal of this research was to understand the nutritional requirement, and determine the 7α-dehydroxylation activity and end products from …