Life Sciences Commons^™

Labile Soil Carbon Inputs Mediate The Soil Microbial Community Composition And Plant Residue Decomposition Rates, Marie-Anne De Graaff, Aimee T. Classen, Hector F. Castro, Christopher W. Schadt

Biology Faculty Publications and Presentations

• Root carbon (C) inputs may regulate decomposition rates in soil, and in this study we ask: how do labile C inputs regulate decomposition of plant residues, and soil microbial communities?

• In a 14 d laboratory incubation, we added C compounds often found in root exudates in seven different concentrations (0, 0.7, 1.4, 3.6, 7.2, 14.4 and 21.7 mg C g soil) to soils amended with and without ¹³C-labeled plant residue. We measured CO₂ respiration and shifts in relative fungal and bacterial rRNA gene copy numbers using quantitative polymerase chain reaction (qPCR).

• Increased labile C input …

Depth And Time Related Variations Of Microbial Communiites In An Emergent Freshwater Wetland, Amy Jenkins

Theses and Dissertations

Soils, and the microbial communities contained within them, are vital for most chemical, physical, and biological processes. This study investigated how microbial community structure responded to environmental changes, such as hydrology, across vertical space (depth) and time in an emergent fresh water wetland. Research was conducted in a non-tidal freshwater wetland along the James River (Charles City County, Virginia) by establishing plots in two areas that experienced different hydrologic regimes and plant communities. Soil cores (30 cm) were collected monthly from January 2008 to February 2009, and then every two to three months thereafter until October 2009, for a total …

Genetic Analysis Of Vancomycin-Resistant Gram-Positive Cocci Isolated From Wild Songbirds, Shingo Ishihara

Master's Theses

The antibiotic vancomycin was developed by Eli Lilly in the 1950s in response to the growing number of Staphylococcus aureus infections that were resistant to penicillin. Vancomycin was not widely used at the time because of its high toxicity. However, use of vancomycin in the United States has increased dramatically since the 1980s because of the emergence of methicillin resistant Staphylococcus aureus (MRSA) and Enterococcus species. There are three known mechanisms for vancomycin resistance: 1) target site modification by van genes, 2) biofilm formation, and 3) bacterial cell wall thickening. Of these mechanisms, target site modification is the most common. …

Communities Of Cloacal Bacteria In Tree Swallow Families, Michael Lombardo, Patrick Thorpe, R. Cichewicz, M. Henshaw, C. Millard, C. Steen, T. Zeller

Michael P Lombardo

Our aim in this study was to survey the communities of bacteria found in the cloacae of adult and nestling Tree Swallows (Tachycineta bicolor), determine if there were familial patterns of prevalence, and determine if there were relationships between bacteria loads and nestling size when 12 days old and fledging success.

Factors Influencing The Abundance, Community Composition And Activity States Of Bacterioplankton From The Tidal Freshwater James River, Catherine Luria

Theses and Dissertations

Aquatic bacteria respond to changing environmental conditions through a variety of mechanisms including changes in abundance, shifts in community composition and variable activity states. In the tidal-freshwater James River, variation in bacterial abundance was linked to nutrient availability and autochthonous production with highest bacterial densities associated with low-nutrient, high-chlorophyll a conditions. Laboratory experiments revealed that bacterial growth rates were nutrient limited at the low-nutrient site, while co-limitation (nutrients, glucose, light) was apparent at the high nutrient site. Despite large differences in abundance, community composition was similar based on TRFLP and 16S rDNA pyrosequencing. Community similarity was lower among rRNA libraries …

Mechanisms Responsible For A Φx174 Mutant's Ability To Infect Escherichia Coli By Phosphorylation, Jennifer Cox, Catherine Putonti

Bioinformatics Faculty Publications

The ability for a virus to expand its host range is dependent upon a successful mode of viral entry. As such, the host range of the well-studied ΦX174 bacteriophage is dictated by the presence of a particular lipopolysaccharide (LPS) on the bacterial surface. The mutant ΦX174 strain JACS-K, unlike its ancestor, is capable of infecting both its native host Escherichia coli C and E. coli K-12, which does not have the necessary LPS. The conversion of an alanine to a very reactive threonine on its virion surface was found to be responsible for the strain's expanded host range.

Environmental Correlates Of Abundances Of Mosquito Species And Stages In Discarded Vehicle Tires, Donald A. Yee, Jamie M. Kneitel, Steven A. Juliano

Faculty Publications – Biological Sciences

Discarded vehicle tires are a common habitat for container mosquito larvae, although the environmental factors that may control their presence or abundance within a tire are largely unknown. We sample discarded vehicle tires in six sites located within four counties of central Illinois during the spring and summer of 2006 to determine associations between a suite of environmental factors and community composition of container mosquitoes. Our goal was to find patterns of association between environmental factors and abundances of early and late instars. We hypothesized that environmental factors correlated with early instars would be indicative of oviposition cues, whereas environmental …