Increasing the efficiency of biofuel production is critical to decrease the dependence and consumption of fossil fuels. In the United States, most car fuel contains about 10% ethanol, the result of fermentation, and 90% gasoline. The process of fermenting sugars into ethanol relies on agricultural stocks, decreasing the area of arable land available for food production. Non-agricultural plant species can be used, but the lignocellulose material from the total plant contains both five and six carbon sugars. Baker’s Yeast can ferment the six carbon sugars, but a novel yeast species is necessary to ferment the five carbon sugars. The goal of my research is to isolate and identify wild yeast species growing in non-agricultural plants that ferment five carbon sugars, such as xylose, into a usable product; xylitol in this case. Xylitol can be sold as an artificial sweetener to subsidize the overall costs of biofuel production, or alternatively, may be converted to ethanol through biochemical pathways that some yeast species have. After attempting to grow yeast from nine different plant species growing in Pack Forest with xylose as their only carbon source, one yeast species from red alder, Alnus rubra, exhibited growth. The other eight species did not show significant growth compared to controls: common Baker's Yeast and PTD3, a previously isolated yeast. Further research of these yeasts was not pursued. Next, AR (for Alnus rubra), was tested for xylitol production. First, AR was grown in a medium with xylose as its sole source of sugar. By placing the growth culture in an air-tight flask, any xylitol production would be prevented from evaporating, making it measurable with a high-performance liquid chromatography machine. The yeast isolated from red alder successfully fermented xylose into xylitol, making it a potential source of efficient biofuel production.

Curiously, Black Cottonwood (Populus trichocarpa) thrives on the rocky riverbanks of Washington under nutrient-poor conditions few other species dare tolerate. Their prosperous lives could be the result of nitrogen-fixing bacteria that inhabit the tree's stems and roots. It is the hypothesis that these endophytic bacteria provide trees with organic nitrogen throughout their lives, where the river side substrate fails to provide sufficient nitrogen for the Poplar to otherwise live. Wild Black Cottonwood seeds were collected from Three Forks Park along the Snoqualmie River in Washington then grown in greenhouses. Endophytes were isolated from these trees and tested for the presence of the nitrogenase gene (nifH) using PCR. The nitrogenase proteins equip bacteria to fix atmospheric nitrogen into forms plants can readily use. Understanding the life cycles, inoculation techniques and genetic make-ups of these bacteria enable us not only to grasp a little better the diversity of life, but to think beyond Black Cottonwoods, to how these bacteria could be recruited to be used on crops and degraded fields. Nitrogen is necessary for plants and often a growth limiting factor; harnessing these nitrogen-providers may help reduce our dependency of energy-intensive industrial ammonia.

The Social Network Index (SNI) (Berkman & Syme, 1979) has been used to demonstrate that people who are more involved with their networks have lower levels of negative emotional effects, such as depression and stress, and fewer occurrences of physical ailments, such as flare-ups of diseases. Demoralization (Dohrenwend, Shrout, Egri, & Mendelsohn, 1980) measures the general physical and mental response of stress. The college age group is underrepresented in SNI research, which added some difficulty interpreting the results. There were four hypotheses: 1- Is SNI related to demoralization experienced by college students? 2- Does the first generation student population have a different average on SNI, demoralization, life satisfaction, and depression than non-first generation students do? 3- Is SNI related to levels of life satisfaction? 4- IS SNI related to self-reported levels of depression? Participants took an online survey for class credit, N=969 usable. Ages ranged from 16 to 47, mean= 21. There were 341 males and 628 females, and 42.5% were first generation college students. We found that those with higher values on the SNI had lower levels of depression(r=-.24) and demoralization (r=-.27), and had higher levels of life satisfaction(r=.32). When comparing the first generation population to the non-first generation student population, we found that only SNI differed significantly, although this small effect is of little practical importance.

Phytoremediation is the use of specific plants to remove pollutants and toxins from soil and water.  Phytoremediating plants can have problems surviving in highly polluted industrial environments, known as Super Fund sites. The Doty Lab has isolated an endophyte bacteria designated "PD.1" that has shown the ability to give plants the strength to become estabilished and productive in these highly toxic environments.  The term endophyte refers to a class of mutually beneficial, symbiotic microbes, which live in the intracellular spaces between cells of inoculated plants, and have been shown to release growth hormones, provide tolerance to drought, flood and high salt environments and can give plants the ability to break down large human-made chemicals into smaller molecules which the plant and microbes can use as a nutrient source . This presentation will show the results of several experiments conducted in hydroponic solutions, and in soil dosed with the Polycyclic Aromatic Hydrocarbon, phenantherene. Several different species of Salix and Populous trees were dosed with high levels of phenantherene after being inoculated with an endophyte bacteria isolated from a Populous deltoids. Growth, plant mortality rates and plant uptake of the pollutant phenantherene were recorded.  In several of these studies there was a dramatic decline in mortality of inoculated plants in highly polluted environments and also signifigant increases in shoot growth of inoculated plants. This research adds to the growing body of work that is demonstrating that the use of plants, inoculated with a corresponding symbiotic, endophytic bacteria can be a viable tool in pollution remediation of soil and water.

Populus trichocarpa, or Black Cottonwood, form a mutualistic relationship with diazotrophic bacteria, in which nitrogen is provided to the host plant in exchange for protection and energy. Understanding this form of symbiosis is essential in determining how biologically available nitrogen is cycled throughout our planet’s biomes. A well-known diazotrophic mutualism is found between leguminous species and Rhizobia or Frankia bacteria, where colonies are established inside root nodules of the host plant. Black Cottonwoods differ from legumes in that they form an endosymbiosis with nitrogen-fixing bacteria recruited from the environment, where the bacteria form colonies throughout the plant tissue. To determine the endophyte source, bacterial samples were obtained from sand, river water, and seed collected at the Three Forks Park in Washington to determine where in the environment Black Cottonwoods are coming into contact with these endophytes, and which species are found at each source. Nitrogen-fixing species were selected for by culturing bacteria using nitrogen free media, and were then subjected to PCR for amplification of the nitrogenase gene for confirmation. Species identification was performed by amplifying the 16sRNA, followed by sequencing and local alignment matching. Of the 29 samples collected from the Three Forks site, 27 were found to carry the nitrogenase gene, and species identification underway. Black Cottonwoods, in addition to other poplar species, have been found to be very useful industrially as biofuels and in the bioremediation of environmental pollutants. Nitrogen-fixation provides a major benefit for using poplars, where the use of fertilizers is reduced. It is thought that there is a common evolutionary link between more plant species and diazotrophic bacteria than is currently known, and understanding which species exist outside of the plant hosts may lead to the reduction of nitrogen-based fertilizer in other industrially useful plants.