Studies in Coffee

Telomeres are important protein-DNA structures at the ends of linear eukaryotic chromosomes that are necessary for genome integrity. Telomeres are maintained by intermittent action of telomerase. I explored the kinetics of telomere length homeostasis in the model plant Arabidopsis thaliana by crossing wild type plants to different generations of telomerase deficient plants, and then analyzing telomere length in the resulting progeny. Unexpectedly, I found plants lacking telomerase for seven generations can lengthen telomeres when telomerase is reintroduced, but one generation is not sufficient to reestablish the telomere set point. Est1 is a non-catalytic component of the Saccharomyces cerevisiae telomerase holoenzyme. To investigate the role of Est1 in higher eukaryotes, I identified two putative Est1 homologues in Arabidopsis, AtEST1a and AtEST1b. Plants deficient in AtEST1a displayed no vegetative or reproductive defects. However, plants deficient for AtEST1b were sterile and had severe vegetative and reproductive irregularities. Surprisingly, no defects in telomere maintenance were observed in any single or double mutant line. This suggests that the Est1- like proteins in plants have evolved new functions outside of telomere length maintenance and end protection.One consequence of telomere dysfunction is end-to-end chromosome fusion. In mammals, telomere fusion is mediated through NHEJ and requires DNA Ligase IV (Lig4). Lig4 is an essential component of the NHEJ pathway along with the Ku70/Ku80 heterodimer and DNA-PKcs. To address the mechanism of chromosome fusion in Arabidopsis, we investigated the role of Lig4 in mutant combinations lacking TERT, the catalytic subunit of telomerase, and Ku70. Surprisingly, telomere end-to-end fusions were observed in ku70 tert lig4 triple mutants, suggesting that neither Lig4 nor Ku70 are required for the fusion of critically shortened telomeres in Arabidopsis. To investigate the origin of genome instability, terminal restriction fragment analysis was performed on triple mutants. Strikingly, telomeres diminished five to six-fold faster than in a tert single mutant. Moreover, in the triple mutants, telomere tracts were extremely heterogeneous, suggesting that the telomeres were exposed to catastophic nucleolytic attack. These data provide the first evidence that Lig4 contributes to telomere maintenance and chromosome end protection.

As energy prices continue to rise, concern grows about the economy and about petroleum supplies. On January 1, 2009 The Energy Independence and Security Act of 2009 was enacted. It states that 500 million gallons of biomass-based biodiesel must be produced in 2009 and 1 billion gallons by 2012. In the United States 90 % of the biodiesel is produced from soybean oil, despite its shortcomings. The biggest problem facing the soy diesel industry is the American Society of Testing and Materials (ASTM) specifications for Biodiesel and Biodiesel Blends. The two categories that are in need of immediate improvement to enhance test results and produce a better burning fuel are cloud point and oxidation stability.Monounsaturated fatty acid methyl ester (FAME) are reported to strike the best balance between cold flow properties and oxidative stability to enhance biodiesel test results and produce a better burning fuel. In addition, treating fuels derived from fatty acid alkyl esters with oxidation inhibitors (antioxidants) has been reported to increase resistance to oxidation. Fuel properties: acid value, cloud point, iodine value, pour point, peroxide value, induction period, onset temperature, and kinematic viscosity were used to evaluate a newly developed Roundup Ready® soybean recombinant inbred line with a novel oil profile, exhibiting an elevated level of monounsaturated FAME and the possibility of using selenium as a natural antioxidant for use in the biodiesel industry. We were able to demonstrate higher polyunsaturated content lead to lower IP values, lower PV values were indicative of increased monounsaturated FAME content and elevated levels of saturated FAME content resulted in higher CP and PP values.

Imidacloprid, a neonicotinoid insecticide, is commonly applied on eastern hemlock to reduce populations of Hemlock woolly adelgid (HWA). A large number of other herbivorous and transient insects also are associated with eastern hemlock. These herbivorous insects may acquire imidacloprid through feeding on treated plants. Predatory insects may acquire imidacloprid when they feed on insecticide-contaminated prey. To investigate this phenomenon, a study was conducted at Indian Boundary Campground, Cherokee National Forest, 2005-2007. This study was conducted to: 1) ascertain the effect of imidacloprid used against HWA on the predatory guild associated with eastern hemlock, 2) determine seasonal abundance of the predatory guild on eastern hemlock, and 3) assess influence of vertical stratification on spiders and other predators.During this study, 4,917 predators representing 75 families and 10 orders were collected. Spiders were the most dominant predator group, and the most abundant spider families were Mimetidae (1,038), Salticidae (736), Araneidae (733), Gnaphosidae (517), Philodromidae (330), Theridiidae (168), Tetragnathidae (161) and Thomisidae (142). The most abundant insect predator families were Vespidae (132), Ichneumonidae (50), Braconidae (31), Pentatomidae (25), Reduviidae (24), Coccinellidae (15), and Elateridae (15). Predator densities were not significantly different between pesticide application times (Fall and Spring). In both years, predator densities in control treatments and horticultural oil treatments were significantly (p<0.05) greater than those in imidacloprid treatments. However, predator densities were not significantly (p<0.05) different among soil drench, soil injection, and tree injection treatments or between control and horticultural oil treatments. Predator densities were at least 1.5-3X greater in the imidacloprid-treated plots in 2007 than in 2006, possibly suggesting a rebound in predator densities 1-1½ years after treatment.Predator densities were significantly (p<0.05) greater in the top and middle canopy than in the lower canopy. Imidacloprid concentration level declined progressively from the bottom stratum to the top stratum of the tree canopy. Highest levels were observed in the bottom stratum which shows that higher concentrations of imidacloprid lead to lower numbers of predators and lower concentrations of imidacloprid lead to higher numbers of predators.

Leadership and leadership development is an important topic facing those who lead and train people in the area of public horticulture. In the fall of 2007 an email survey consisting of 55 questions was sent to 448 executive directors of public gardens in the United States. This survey was divided into six major sections: demographics on each director‟s garden and their association with their garden; each directors view of leadership in their garden and in the field of public horticulture; each directors experience with, and their view on the importance of internships; leadership style; each directors level of confidence, and their views on the importance of different aspects of their job; general personal demographic information and each directors‟ comments.Results from this study suggest current garden directors have an interest in furthering their own knowledge in the area of leadership. The results from this study also revealed leaders of public gardens in the U.S. lead using a participative style of leadership. This style of leadership fosters an environment where subordinates opinions are taken into consideration when making decisions. Respondents to this study also value experiences during college at a high level in regards to choosing their career path. This includes participation in hands-on work experiences such as internships. In conclusion, those who currently lead public gardens typically feel that the ability to communicate is the most important aspect of what they do. Unfortunately, this is also an area where current directors lack personal confidence and desire professional development.

Flue Gas Desulfurization (FGD) gypsum is a potential soil amendment for agricultural use in the state of Tennessee. FGD gypsum is a potential source of calcium and sulfur that may improve the soil both chemically and physically. FGD gypsum has the potential to raise pH, improve soil structure, increase infiltration rates, ameliorate subsoil acidity and improve crop yields. However, the addition of gypsum can also lower pH in some circumstances and cause magnesium and potassium losses in soil. In this study FGD gypsum was applied at a single rate to fields on thirteen farms located on the northern and southern Highland Rim and in the southern Outer Central Basin region of the state.These fields were then managed in conjunction with the farms’ conventional practices. Soil samples were collected and analyzed for pH, K, Ca, Mg and Al. Results showed that the application of FGD gypsum can either increase or decrease pH with the dependent factor seeming to be the initial pH level of the soil. Decreases were seen in K and Mg content of the soil. On the sites with the most acid subsoils, exchangeable aluminum was reduced in the upper subsoil. Increases in Ca were observed deep into the profile after the second year of the study. Soil physical properties were largely unchanged, as indicated by penetrometer, soil water and bulk density measurements.It is believed that the traffic associated with the application of the FGD gypsum negated most of the beneficial structural effects that are often seen with mined gypsum. Also since most of the locations were managed as no-till systems the effects of gypsum on water infiltration were negated by the residue left on top of the soil surface. This resulted in the absence of effect in the soil water measurements that were collected over the two years of the study. Corn yields were seen to improve after the application of FGD gypsum indicating the material is potentially a viable option for some farming operations in the state.

Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2001. / Field problem. Includes bibliographical references.

Thesis (Ph. D.)--Universiteit van Amsterdam, 1909. / Includes bibliographical references.

Thèse--Universit́e de Genéve. / "Bibliographie": p. 90-100.

Thesis (Ph. D.)--University of Chicago, 1915. / "A private edition distributed by the University of Chicago libraries." "Reprinted from the Botanical gazette, vol. I, XII, no. 2." "Contributions from the Hull botanical laboratory 218." "Literature cited": p. 132.