Other Life Sciences Commons^™

Impact Of Crop And Residue Management On The Physical And Chemical Stabilization Of Soil Organic Matter At Farm Level, Ana B. Wingeyer

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

This dissertation explores changes over time in soil organic matter (SOM) stabilization of two irrigated production fields: a continuous maize sequence that was converted from no-till to conservation deep tillage (Site 1), and a no-till maize-soybean rotation (Site 2). An integrated approach using humic acid extractions and density-based physical fractionation of SOM within aggregate size classes was developed to evaluate the changes in SOM stabilization (physical protection, organo-mineral associations and humification). At Site 1, loss of SOM in the surface layer was compensated for by increased SOM in deeper soil layers with no net change in C stocks. Whole field …

Zap1 Control Of Cell-Cell Signaling In Candida Albicans Biofilms, Shantanu Ganguly, Andrew C. Bishop, Wenjie Xu, Suman Ghosh, Kenneth W. Nickerson, Frederick Lanni, Jana Patton-Vogt, Aaron P. Mitchell

Kenneth Nickerson Papers

Biofilms of Candida albicans include both yeast cells and hyphae. Prior studies indicated that a zap1/ mutant, defective in zinc regulator Zap1, has increased accumulation of yeast cells in biofilms. This altered yeast-hypha balance may arise from internal regulatory alterations or from an effect on the production of diffusible quorum-sensing (QS) molecules. Here, we develop biosensor reporter strains that express yeastspecific YWP1-RFP or hypha-specific HWP1-RFP, along with a constitutive TDH3-GFP normalization standard. Seeding these biosensor strains into biofilms allows a biological activity assay of the surrounding biofilm milieu. A zap1/ biofilm induces the yeast-specific YWP1-RFP reporter in a wild-type …

Impact Of Alternative Range Management Systems On Grasslands In The Central Platte River Valley, Nebraska, Luis E. Ramirez

School of Natural Resources: Dissertations, Theses, and Student Research

Land management strategies can directly and indirectly affect plant assemblages and their behavior. Little research has been performed in south central Nebraska to quantify the effect of fire and grazing interactions on species composition, vegetation structure, forage quality, and potential cost associated with land management.

I evaluate the effect of season-long continuous, patch-burning, and rotational grazing approaches on vegetation and ranching costs to determine their value as conservation tools. This study includes data collected between 2007 and 2009 from grasslands in south central Nebraska. I found that land management influence plant assemblages by shifting communities when grazing and/or fire are …

Creating An Environmental Placed Based Education At Norris Elementary, Ben Kittrell

Department of Environmental Studies: Undergraduate Student Theses

This study is focused on creating a place based education program. Place based education programs provide many benefits at the personal level with the students (PBEEC). The study was completed at Norris Elementary School where the students have access to the “Norris Forest” which is a planted forest with a walk way through the trees. Some of the trees are labeled for the students to identify and others are not. A graph of the unlabelled trees has been included for the students or the teachers to use.

This project incorporates activities that will engage the students in order to teach …

Designing A School Garden Space That Emphasizes Children's Wants And Uses Permaculture Design Methods, Mikhaela Mullins

Department of Environmental Studies: Undergraduate Student Theses

A case study was organized at Saratoga Elementary school in Lincoln, Nebraska to obtain data on what children desire in a garden space. To collect this data a school garden space was constructed and an after school garden club was implemented. Students who participated in the after school garden club partook in the study by drawing their ideal garden. Elements that the subjects drew were identified and categorized into ‘highly desired’ and ‘somewhat desired’.

These elements were then incorporated into a proposed garden design plan for Saratoga. The proposal plan uses Permaculture design methods to emphasize sustainability.

Dur3 Is The Major Urea Transporter In Candida Albicans And Is Co-Regulated With The Urea Amidolyase Dur1,2, Dhammika H. M. L. P Navarathna, Aditi Das, Joachim Morschhauser, Kenneth W. Nickerson, David D. Roberts

Kenneth Nickerson Papers

Hemiascomycetes, including the pathogen Candida albicans, acquire nitrogen from urea using the urea amidolyase Dur1,2, whereas all other higher fungi use primarily the nickel-containing urease. Urea metabolism via Dur1,2 is important for resistance to innate host immunity in C. albicans infections. To further characterize urea metabolism in C. albicans we examined the function of seven putative urea transporters. Gene disruption established that Dur3, encoded by orf 19.781, is the predominant transporter. [¹⁴C]Urea uptake was energy-dependent and decreased approximately sevenfold in a dur3D mutant. DUR1,2 and DUR3 expression was strongly induced by urea, whereas the other putative transporter genes …