Pseudomonas fluorescens strain L5.1-96 has been known to help combat the wheat take-all fungal pathogen, Gaeumannomyces graminis var. tritici (Ggt). Strain L5.1-96 is maintained in the soil longer than others, so it is known as a supercolonizer, which contributes to the phenomenon referred to as Take-All Decline (TAD). The strain L5.1-96 is a non-pathogenic bacterium which grows in the rhizosphere of plants and produces an antifungal agent known as 2.4-diacetylphloroglucinol (DAPG) causing TAD. The DNA fragment we amplified, sequenced, and analyzed was a perfect match to P. brassicacearum strain BS3663. Through bioinformatics, we also found our fragment matched the genetic code for pyridoxal 5'-phosphate (PLP)-dependent aminotransferase, a co-enzyme which catalyzes the transamination of amino acids to alpha-keto acids. We did not identify new proteins that are responsible for the advantages that this bacterium holds against wheat take-all; although, we did find the best phylogenetic fit for this strain. These findings contribute information to the broader study at Washington State University to investigate whether strain L5.1-96 can be used as a biocontrol agent against wheat take-all.​

My presentation reviews existing literature on the use of boron clusters in liquid crystals. Liquid crystalline substances are usually composed of long, thin carbon-based (organic) molecules and have applications in electronic display technology and chromatography. Many compounds with liquid crystalline phases contain rigid substituent groups. The rigidity of inorganic boron clusters and their ability to form linear compounds by attaching groups to atoms on opposite ends of the cluster make them an intriguing starting point for the synthesis of new liquid crystalline materials. Work conducted on the synthesis and properties of boron cluster-based liquid crystals in comparison with organic cyclohexane- or benzene-based analogues is discussed. In addition, new derivatives of a specific boron cluster, CB11­H12­-, synthesized in our lab using microwave and stardard Schlenk line techniques, are presented, along with an evaluation of their potential as precursors for new liquid crystals. We present a relaible pathway to a new difunctionalized carboxylic acid derivative.

The purpose of this study was to explore the interrelationship between two major DNA repair systems--photoreactivation, with blue light as an energy source, and excision repair, which uses ATP as an energy source--of Chlamydomonas reinhardtii, a single-celled algae, by studying the in vivo efficiency of photoreactivation when the excision repair system was suppressed. Working with a mutant which was completely lacking in excision repair, we found that this strain was also deficient in photoreactivation, as compared to wild-type, at low levels of post-UV visible light treatment, measured by killing on plates. We hypothesized that the level of light intensity might have an impact on the efficiency of the photoreactivating enzyme. Using alkaline agarose gel electrophoresis analysis, we quantitatively evaluated the extent of repair of DNA damage over 24 hours under two different light intensities. We found less damage removal in the mutant under low light intensity, suggesting that a positive correlation does indeed exist between the flux of visible light used in our experiments and the amount of photoreactivation for the mutant. This correlation was not observed in the wildtype. Our work is interesting in the context of human-caused changes to Earth’s atmosphere; both photoreactivation and excision repair of DNA damage are present in virtually all organisms studied, including bacteria, fungi, plants and most animals (although not in placental mammals). With the weakening of the stratospheric ozone layer, there is the possibility of increasing solar UV flux to the surface of Earth, with possible negative downstream effects on biological systems. Understanding the functional relationship between these two DNA repair systems could provide information of fundamental importance to ecological and agricultural problems arising from increased solar UV flux to Earth.

Conventional farming techniques involve large quantities of chemical fertilizers, which often leach into bodies of water causing eutrophication. The influx of excess nutrients from fertilizer results in rapid increase of aquatic algal populations followed by dissolved oxygen depletion. This process creates regions of low oxygen that negatively impact the water quality of many major lakes and coastal regions. To address this problem, the sensitivity of plant growth-promoting bacteria (PGPB) to excess fertilizer was investigated. We hypothesize that the addition of high amounts of fertilizer will result in smaller, less productive plants and diminished rhizosphere colonization of the PGPB, Bacillus subtilis. A modified Kirby-Bauer disk diffusion test was performed as an initial assessment of the effect of varied fertilizer concentrations on B. subtilis. Roots of romaine lettuce seedlings were then inoculated with B. subtilis and grown in soil treated with the same range of fertilizer concentrations. The effects of each treatment on plant growth were determined using total leaf area, quantification of the rhizosphere colonization by B. subtilis, and carbon assimilation measured with a LI-6800 Portable Photosynthesis System. These results are an important step towards establishing guidelines for appropriate application of agricultural fertilizer in order to mitigate the frequency and severity of eutrophication events in aquatic systems.