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S-adenosylmethionine (SAMe) is the most common methyl donor found in living organisms. It is the second most common cellular enzyme substrate and is an essential molecule in the carbon metabolic cycle. SAMe is widely used in both a clinical setting and as a nutritional supplement to treat a variety of disorders ranging from liver disease to osteoarthritis in both humans and animals. Demand for SAMe is rapidly expanding and the yeast Saccharomyces cerevisiae is often used as an industrial production host. Increasing clinical research into SAMe, as well as increasing commercial demand, has led to the need for rapid, accurate measurement of SAMe levels from a variety of sources. We report here a novel hydrophilic interaction liquid chromatography (HILIC) UltraPerformance liquid chromatography – mass spectrometry (UPLC-MS) benchtop method to measure intracellular levels of SAMe from S. cerevisiae. Research is ongoing to understand the cellular impact of variations in SAMe levels as well as mutation screens to identify yeast strains with increased SAMe production. This UPLC method allows researchers to measure SAMe with increased resolution, speed, and sensitivity while decreasing both cost and environmental impact, and has the potential to be adapted for the measure of many other metabolites.
Soil conservation practices such as minimum tillage, crop rotation, cover crops, and manure application have strong advocacy. Short-term evidence that these practices are beneficial might improve their adoption by resource-limited producers. A two-year study (2015–2017) was conducted on a privately-owned small, limited-resource farm in southwestern Kentucky to evaluate how cover crops and manure application, alone or in combination, influenced soil nutrient availability, nitrogen mineralization, and crop yield. Three fertilization treatments were used: 1) poultry manure; 2) chemical fertilizers (urea, diammonium phosphate, and potash); and 3) a non-fertilized control. A second set of treatments consisting of presence or absence of winter cover crop was used within each fertilization treatment. The cover crop consisted of a cereal rye (Secale cereale L.), Austrian winter pea (Pisum sativum L.), and crimson clover (Trifolium incarnatum L.) mix. Summer crops consisted of a no-till maize (Zea mays L.) - soybean (Glycine max L.) rotation. Soil samples were taken before and after each summer crop season and analyzed for bulk density, organic carbon content, pH, cation exchange capacity, total phosphorus (P), potassium (K), trace elements, and soil nitrogen (N) mineralization. Cover crops with or without manure enhanced soil N mineralization rates and increased soil extractable P and K, but did not significantly improve yield. Considering the site-specific soil conditions, cover crop and manure use may need longer-term assessment to reveal their effect on the yield and soil quality benefits, especially to resource-limited producers adopting these conservation practices.
Simulations of an organized convective system interacting with Louisville, KY were conducted to determine the impact of urban heat island (UHI) magnitude on the structure and intensity of convective storms. Four different simulations are presented: A control, two simulations in which the UHI is enhanced through observational nudging, and a simulation where the urban area is removed (no-city simulation). Results show that the downwind enhancement of convective cells increases with increasing UHI magnitude. However, large differences are also apparent between the control and the no-city simulations. This suggests that surface convergence caused by flow obstruction may be as influential to the modification of organized storms as the UHI, although the locations of these two effects are offset. Convergence due to flow obstruction is most noticeable on the upwind edge and over the center of the city while the impact of UHI magnitude is most noticeable on the downwind edge of the city.
Constructing buildings, sidewalks, parking lots, and roads inadvertently affects local climate. The best studied example of this, the urban heat island (UHI), manifests as elevated temperatures in developed areas compared to less developed areas nearby. This phenomenon affects many things including plants, wildlife, energy consumption, and human health. We assess the UHI at Eastern Kentucky University (EKU) using simultaneous air temperature observations from two stations. The “urban” station is located on EKU's Richmond campus; the “rural” station is in a non-irrigated pasture 12.9 km away. EKU's heat island follows a typical diurnal pattern, developing during the hours surrounding sunset and dissipating soon after sunrise. Dry air masses with little to no cloud cover and calm winds are favorable for UHI development. Analyzing only nocturnal observations when wind speed was less than 1 m/s, revealed an average urban-rural temperature difference of 3.35°C, though concurrent differences sometimes exceed 10°C. At EKU, the smallest average monthly UHI occurs in February and the largest average monthly UHI occurs in August and September. Strategic tree planting offers an attractive means of mitigating negative impacts on warm season cooling costs and human comfort, while also contributing to campus sustainability goals.
Kentucky's crayfish faunal list has undergone considerable changes since the publication of Crayfishes of Kentucky (Taylor and Schuster, 2004). We conducted an in-depth literature review and reviewed collection databases to develop an up-to-date checklist of crayfish species known to occur in Kentucky. Sixty-five crayfish species have been documented from Kentucky to date, including twelve new species described and three state records since 2004. One new species description (Faxonius sp. A. nov. sp.) is currently underway and was included in the species list for future reference. Additionally, we provide information on changes in crayfish taxonomy, crayfish species that may occur in Kentucky, and potential cryptic species where additional research may result in new species being detected. We hope this information provides clarity for researchers and resource managers and encourages additional crayfish research in Kentucky.
Functional iteration, the process of forming a sequence x0, x1 = f(x0), x2 = f(x1) = f(f(x0)) = f2(x0), . . ., by repeated application of a function f, is fundamental to the approximation of solutions to nonlinear equations and plays an important role in the study of nonlinear dynamics. In this note we examine another aspect of functional iteration: the global behavior of the sequence f, f2, f3, . . ., fn, . . . of composite functions as n → ∞. This topic can be presented to students at many levels using computer graphics to stimulate conjectures that can then be investigated theoretically.