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An Investigation Into Bacterial Contamination In An Urban Nebraska Stream Using Microbial Source Tracking, Allison R. Speicher

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

High levels of fecal bacteria in surface waters are a public health concern due to the enteric illnesses caused by primary contact with these waters. Shortcomings in the current fecal indicator bacteria (FIB) monitoring approach and the ubiquity of pathogen-impaired water bodies has led to the development of microbial source tracking (MST), a molecular tool that can identify potential fecal contamination sources. In this study we use a bacterial community based approach examining the V4 region of the 16S rRNA gene to elucidate sources of fecal bacteria in Antelope Creek, an urban creek in Lincoln Nebraska.

We hypothesized that sediment …

Steps In Metagenomics: Let’S Avoid Garbage In And Garbage Out, Jacques Izard

Department of Food Science and Technology: Faculty Publications

Is metagenomics a revolution or a new fad? Metagenomics is tightly associated with the availability of next-generation sequencing in all its implementations. The key feature of these new technologies, moving beyond the Sanger-based DNA sequencing approach, is the depth of nucleotide sequencing per sample.Knowing much more about a sample changes the traditional paradigms of “What is the most abundant?” or “What is the most significant?” to “What is present and potentially sig­nificant that might influence the situation and outcome?” Let’s take the case of identifying proper biomarkers of disease state in the context of chronic disease prevention. Prevention has been …

Individual Responses For Muscle Activation, Repetitions, And Volume During Three Sets To Failure Of High- (80% 1rm) Versus Low-Load (30% 1rm) Forearm Flexion Resistance Exercise, Nathaniel D.M. Jenkins, Terry J. Housh, Samuel L. Buckner, Haley C. Bergstrom, Kristen C. Cochrane, Cory M. Smith, Ethan C. Hill, Richard J. Schmidt, Joel T. Cramer

Department of Nutrition and Health Sciences: Faculty Publications

This study compared electromyographic (EMG) amplitude, the number of repetitions completed, and exercise volume during three sets to failure of high- (80% 1RM) versus low-load (30% 1RM) forearm flexion resistance exercise on a subject-by-subject basis. Fifteen men were familiarized, completed forearm flexion 1RM testing. Forty-eight to 72 h later, the subjects completed three sets to failure of dumbbell forearm flexion resistance exercise with 80% (n = 8) or 30% (n = 7) 1RM. EMG amplitude was calculated for every repetition, and the number of repetitions performed and exercise volume were recorded. During sets 1, 2, and 3, one of eight …

Knowledge, Use And Perceptions Of Probiotics And Prebiotics In Hospitalized Patients, Melanie Betz, Anne Uzueta, Heather Rasmussen, Mary Gregoire, Cassandra Vandrwall, Gretchen Witowich

Department of Nutrition and Health Sciences: Faculty Publications

Aim: Little is known about inpatient probiotic and prebiotic consumption or beliefs, despite their increase in availability. Therefore, the purpose of this research was to assess inpatient knowledge, use and perceptions of probiotics and prebiotics.

Methods: All subjects were inpatients at two urban medical centers on general medical/surgical floors. Patients were randomly selected to complete a verbally administered questionnaire inquiring about probiotic and prebiotic knowledge, use and perceptions. Patient responses were recorded directly into Survey Monkey (Palo Alto, CA, USA) on a computer.

Results: Patients (n = 200) were 58% were women and 56% were Caucasian with a mean age …

Using A Simple Leaf Color Chart To Estimate Leaf And Canopy Chlorophyll A Content In Maize (Zea Mays), Anthony Nguy-Robertson, Yi Peng, Timothy Arkebauer, David Scoby, James Schepers, Anatoly Gitelson

Department of Agronomy and Horticulture: Faculty Publications

This study utilized a leaf color chart (LCC) to characterize the variation in leaf chlorophyll and estimate canopy chlorophyll in maize (Zea mays). The LCC consisted of four levels of greenness and was used to sort maize leaves in 2011 for three fields near Mead, Nebraska, USA. Leaf chlorophyll content for each color chart class was determined using two leaf-level sensors. The variation within each LCC class was reasonable (CV < 56%). The darkest color class predominated and indicated adequate fertilization rates using a SPAD. Canopy chlorophyll content was estimated using destructively measured leaf area index (LAI) and the LCC. This approach was verified with a method utilizing canopy reflectance collected by both satellite imagery and a four-band radiometer. The error between the two methods was reasonable (RMSE = 0.55-0.88 g m^-2; CV = 25.6-50.4%), indicating that both leaf and canopy chlorophyll can be estimated cheaply without a wet lab or field-based sensors.

Selection For Silage Yield And Composition Did Not Affect Genomic Diversity Within The Wisconsin Quality Synthetic Maize Population, Aaron Lorenz, Timothy M. Beissinger, Renato Rodrigues Silva, Natalia De Leon

Department of Agronomy and Horticulture: Faculty Publications

Maize silage is forage of high quality and yield, and represents the second most important use of maize in the United States. The Wisconsin Quality Synthetic (WQS) maize population has undergone five cycles of recurrent selection for silage yield and composition, resulting in a genetically improved population. The application of high-density molecular markers allows breeders and geneticists to identify important loci through association analysis and selection mapping, as well as to monitor changes in the distribution of genetic diversity across the genome. The objectives of this study were to identify loci controlling variation for maize silage traits through association analysis …

Overexpression Of The Transporters Atzip1 And Atmtp1 In Cassava Changes Zinc Accumulation And Partitioning, Eliana Gaitán-Solis, Nigel J. Taylor, Dimuth Siritunga, William Stevens, Daniel P. Schachtman

Department of Agronomy and Horticulture: Faculty Publications

Zinc deficiency in humans is a serious problem worldwide with an estimated one third of populations at risk for insufficient zinc in diet, which leads to impairment of cognitive abilities and immune system function. The goal of this research was to increase the bioavailable zinc in the edible portion of cassava roots to improve the overall zinc nutrition of populations that rely on cassava as a dietary staple. To increase zinc concentrations, two Arabidopsis thaliana genes coding for ZIP1 and MTP1 were overexpressed with a tuber-specific or constitutive promoter. Eighteen transgenic events from four constructs, out of a total of …

Potential For Crop Production Increase In Argentina Through Closure Of Existing Yield Gaps, Fernando Aramburu Merlos, Juan Pablo Monzon, Jorge L. Mercau, Miguel Taboada, Fernando H. Andrade, Antonio J. Hall, Esteban Jobbagy, Kenneth Cassman, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Favorable climate and soils for rainfed crop production, together with a relatively low population density,results in 70–90% of Argentina grain production being exported. No assessment to date has tried to estimate the potential for extra grain production for soybean, wheat and maize, which account for 78%of total harvested area, by yield gap closure on existing cropland area and its impact at a global scale.The objectives of this paper are (i) to estimate how much additional grain could be produced without expanding crop area by closing yield gaps in Argentina, (ii) to investigate how this production and yield gaps varies across …

Plants Coping Abiotic And Biotic Stresses: A Tale Of Diligent Management, Hatem Rouached, Sikander Pal, Shimon Rachmilevitch, Marc Libault, Lam-Son Phan Tran

Department of Agronomy and Horticulture: Faculty Publications

Plants unlike other living forms are sessile thereby facing severe biotic and abiotic stresses. Plants have evolved different efficient defence responses which thrive upon a number of intrinsic factors, such as genotypic and phenotypic constitutions and developmental circumstances, and extrinsic factors like severity and duration of the stresses. Stress management uses molecular and biochemical level controls, the competence, and speed, at which a stress signal is perceived and transmitted to generate stress signal molecules and activate stress-protective mechanisms. A well-concerted action of the plants’ competence at morphological, physiological, biochemical, and molecular strata regulates numerous adaptive responses to biotic and abiotic …

Invaded Invaders: Infection Of Invasive Brown Treesnakes On Guam By An Exotic Larval Cestode With A Life Cycle Comprised Of Non-Native Hosts, Elden T. Holldorf, Shane R. Siers, Jonathan Q. Richmond, Page E. Klug, Robert N. Reed

United States Department of Agriculture Wildlife Services: Staff Publications

Background: Multiple host introductions to the same non-native environment have the potential to complete life cycles of parasites incidentally transported with them. Our goal was to identify a recently detected parasitic flatworm in the invasive Brown Treesnake (Boiga irregularis) on the remote Pacific island of Guam. We considered possible factors influencing parasite transmission, and tested for correlations between infection status and potential indicators of host fitness. We used genetic data from the parasite and information about the native ranges of other possible non-native hosts to hypothesize how it arrived on Guam and how its life cycle may be …

Impact Of Capture And Transportation Methods On Survival Of Small Rodents During Relocation Events, Roger A. Baldwin, Ryan Meinerz, Holly E. Jantz, Gary W. Witmer

United States Department of Agriculture Wildlife Services: Staff Publications

Capture and transportation of wild rodents is needed to supply study animals for laboratory or enclosure studies and for translocation of threatened and endangered species. Stress of captured rodents must be minimized to maximize survival. Methods to limit stress include minimizing capture and transportation durations, providing sufficiently sized housing with adequate nesting materials and foods, and ensuring that animals are maintained in comfortable environmental conditions. We utilized these techniques to capture and transport California voles (Microtus californicus) and pocket gophers (Thomomys bottae) from California to Colorado to determine their rate of survival during this process. We …

Food Habits Of Adult Male White-Tailed Deer Determined By Camera Collars, Michael J. Lavelle, Chad R. Blass, Justin W. Fischer, Scott E. Hygnstrom, David G. Hewitt, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Many factors influence what and why animals select the foods they eat. Several methods have been used to estimate food habits of herbivores, but they all have limitations such as defining available foods and misrepresenting particular forages. We evaluated plant consumption by adult male white-tailed deer (Odocoileus virginianus) with camera collars in a semi-enclosed population in southern Texas, USA, during late autumn 2010. We collected 1,241 videos taken at all times of the day and night from 15 camera collars and confirmed consumption of 40 plant species with an 84% probability of identification. Diets of individual deer varied …

To Cross Or Not To Cross: Modeling Wildlife Road Crossings As A Binary Response Variable With Contextual Predictors, Shane R. Siers, Robert N. Reed, Julie A. Savidge

United States Department of Agriculture Wildlife Services: Staff Publications

Roads are significant barriers to landscape-scale movements of individuals or populations of many wildlife taxa. The decision by an animal near a road to either cross or not cross may be influenced by characteristics of the road, environmental conditions, traits of the individual animal, and other aspects of the context within which the decision is made. We considered such factors in a mixed-effects logistic regression model describing the nightly road crossing probabilities of invasive nocturnal Brown Treesnakes (Boiga irregularis) through short-term radiotracking of 691 snakes within close proximity to 50 road segments across the island of Guam. All …

Evaluating Behavioral Syndromes In Coyotes (Canis Latrans), Julie K. Young, Marion Mahe, Stewart W. Breck

United States Department of Agriculture Wildlife Services: Staff Publications

As more research focuses on behavioral syndromes and their role in ecological and evolutionary processes, it is imperative that methods to test behavior are valid. The objectives of this study were to (1) assess behavior in captive coyotes (Canis latrans) using three methods [agitation scores, novel object test, and flightinitiation distance (FID)] and (2) to determine whether the three tests were correlated within individuals to describe behavioral syndromes. Female coyotes had higher agitation scores during handling (2.6 ± 0.5) than males (1.5 ± 0.3; t = 1.90, p = 0.06): scores ranged from 0 to 8 on a …

An Individual-Based Model For Feral Hogs In Great Smoky Mountains National Park, Rene A. Salinas, William H. Stiver, Joseph L. Corn, Suzanne Lenhart, Charles Collins, Marguerite Madden, Kurt C. Vercauteren, Brandon S. Schmit, Ellen Kasari, Agricola Odoi, Graham Hickling, Hamish Mccallum

United States Department of Agriculture Wildlife Services: Staff Publications

The expansion of feral hog (Sus scrofa) populations in the United States has resulted in increased efforts to develop and implement control strategies designed to minimize the impacts done by this invasive species. We describe an individual-based model for feral hogs in Great Smoky Mountains National Park (GSMNP). The objectives of the model are to provide an understanding of the population dynamics of this feral hog population and to determine the efficacy of the annual harvest as a population control method. Results suggest that the dynamics of the population are driven by fall hard mast production and the …

Assessing Chemical Control Of Earthworms At Airports, Thomas W. Seamans, Bradley F. Blackwell, Glen E. Bernhardt, Daniel A. Potter

United States Department of Agriculture Wildlife Services: Staff Publications

Earthworms originating from Europe (e.g., Lumbricus spp., Aporrectodea spp.), which are common in the United States and southern Canada can create hazardous conditions at airports by attracting birds that pose a threat to aircraft. These nonnative earthworms are also considered pests on golf courses and sports fields, as well as having detrimental effects on temperate boreal forests. No toxicants or repellents are currently registered for earthworm control in the United States. Our purpose was to identify products that could be used to repel or suppress nonnative earthworms on airports or other managed sites where they pose a hazard or nuisance. …

Shifting Perceptions Of Risk And Reward: Dynamic Selection For Human Development By Black Bears In The Western United States, H. E. Johnson, S. W. Breck, S. Baruch-Mordo, D. L. Lewis, C. W. Lackey, K. R. Wilson, J. Broderick, J. S. Mao, J. P. Beckmann

United States Department of Agriculture Wildlife Services: Staff Publications

As landscapes across the globe experience increasing human development, it is critical to identify the behavioral responses of wildlife to this change given associated shifts in resource availability and risk from human activity. This is particularly important for large carnivores as their interactions with people are often a source of conflict, which can impede conservation efforts and require extensive management. To examine the adaptations of a large carnivore to benefits and risks associated with human development we investigated black bear behavior in three systems in the western United States. Our objectives were to (1) identify temporal patterns of selection for …

Best Practice Guidelines For Rat Eradication On Tropical Islands, B. B. Keitt, R. Griffiths, S. Boudjelas, K. Broome, S. Cranwell, J. Millett, W. Pitt, A. Samaniego-Herrera

United States Department of Agriculture Wildlife Services: Staff Publications

Invasive vertebrates are a leading cause of extinction on islands and rats (Rattus spp.) are one of the most damaging to island ecosystems. Methods to eradicate rats from islands are well established and there have been over 580 successful eradications to date. Increasingly, rat eradications are being implemented on tropical islands, a reflection of the need to protect the threatened biodiversity in the tropics. Yet rat eradications on tropical islands fail more frequently than those in temperate climates. In an effort to identify the main reasons for the lower success rate on tropical islands and possible solutions, a workshop …

Deer Response To Exclusion From Stored Cattle Feed In Michigan, Usa, Michael J. Lavelle, Henry Campa Iii, Kyle Ledoux, Patrick J. Ryan, Justin W. Fischer, Kim M. Pepin, Chad R. Blass, Michael P. Glow, Scott E. Hygnstrom, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Disease and damage from white-tailed deer (Odocoileus virginianus) continually threaten the livelihood of agricultural producers and the economy in the United States, as well as challenge state and federal wildlife managers. Threats can be partially addressed by excluding free-ranging deer from livestock-related resources. Throughout the year, use of stored livestock feed by deer in northern Lower Michigan (MI), USA fluctuates, though their presence is relatively consistent. Since 2008, use of livestock areas and resources by deer has been reduced through intensive efforts by livestock producers in cooperation with state and federal agencies. These efforts focused on excluding deer …

Establishing A Definition Of Polar Bear (Ursus Maritimus) Health: A Guide To Research And Management Activities, Kelly A. Park, Colleen Duncan, Pauline Noi, Christian Sonne, Kristin Laidre, Martyn Obbard, Oystein Wiig, Jon Aars, Eric Regehr, Lori L. Gustafson, Todd Atwood

United States Department of Agriculture Wildlife Services: Staff Publications

The meaning of health for wildlife and perspectives on how to assess and measure health, are not well characterized. For wildlife at risk, such as some polar bear (Ursus maritimus) subpopulations, establishing comprehensive monitoring programs that include health status is an emerging need. Environmental changes, especially loss of sea ice habitat, have raised concern about polar bear health. Effective and consistent monitoring of polar bear health requires an unambiguous definition of health. We used the Delphi method of soliciting and interpreting expert knowledge to propose a working definition of polar bear health and to identify current concerns regarding …

Modeling And Mapping The Probability Of Occurrence Of Invasive Wild Pigs Across The Contiguous United States, Meredith L. Mcclure, Christopher L. Burdett, Matthew L. Farnsworth, Mark W. Lutman, David M. Theobald, Philip D. Riggs, Daniel A. Grear, Ryan S. Miller

United States Department of Agriculture Wildlife Services: Staff Publications

Wild pigs (Sus scrofa), also known as wild swine, feral pigs, or feral hogs, are one of the most widespread and successful invasive species around the world. Wild pigs have been linked to extensive and costly agricultural damage and present a serious threat to plant and animal communities due to their rooting behavior and omnivorous diet. We modeled the current distribution of wild pigs in the United States to better understand the physiological and ecological factors that may determine their invasive potential and to guide future study and eradication efforts. Using national-scale wild pig occurrence data reported between 1982 and …

Evaluation Of Anthelmintic Fishmeal Polymer Baits For The Control Of Baylisascaris Procyonis In Free-Ranging Raccoons (Procyon Lotor), Timothy J. Smyser, Shylo R. Johnson, Melissa D. Stallard, Ashley K. Mcgrew, L. Kristen Page, Nikki Crider, Lora R. Ballweber, Robert K. Swihart, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Baylisascaris procyonis is a common gastrointestinal parasite of raccoons (Procyon lotor) and is a zoonotic helminth with the potential to cause severe or fatal infection. Raccoons thrive in human-dominated landscapes, and the fecal-oral transmission pathway and lack of effective treatment make B. procyonis a serious threat to public health. The distribution of medicinal baits has emerged as a socially acceptable and cost-effective method for managing disease in free-ranging wildlife. We assessed the suitability of a mass-producible anthelmintic bait for B. procyonis mitigation by evaluating the willingness of free-ranging raccoons to consume anthelmintic baits and determining whether bait consumption …

Seasonal Shifts In Diet And Gut Microbiota Of The American Bison (Bison Bison), Gaddy T. Bergmann, Joseph Craine, Michael S. Robeson, Noah Fierer

United States Department of Agriculture Wildlife Services: Staff Publications

North American bison (Bison bison) are becoming increasingly important to both grassland management and commercial ranching. However, a lack of quantitative data on their diet constrains conservation efforts and the ability to predict bison effects on grasslands. In particular, we know little about the seasonality of the bison diet, the degree to which bison supplement their diet with eudicots, and how changes in diet influence gut microbial communities, all of which play important roles in ungulate performance. To address these knowledge gaps, we quantified seasonal patterns in bison diet and gut microbial community composition for a bison herd in …

Molecular Targets Of Antihypertensive Peptides: Understanding The Mechanisms Of Action Based On The Pathophysiology Of Hypertension, Kaustav Majumder, Jianping Wu

Department of Food Science and Technology: Faculty Publications

There is growing interest in using functional foods or nutraceuticals for the prevention and treatment of hypertension or high blood pressure. Although numerous preventive and therapeutic pharmacological interventions are available on the market, unfortunately, many patients still suffer from poorly controlled hypertension. Furthermore, most pharmacological drugs, such as inhibitors of angiotensin-I converting enzyme (ACE), are often associated with significant adverse effects. Many bioactive food compounds have been characterized over the past decades that may contribute to the management of hypertension; for example, bioactive peptides derived from various food proteins with antihypertensive properties have gained a great deal of attention. Some …

Managing Threats To The Urban Forest: From Dutch Elm Disease To Emerald Ash Borer - Learning From Experience, Christopher J. Borman

Doctor of Plant Health Program: Dissertations and Student Research

The urban forest provides important essential services to all municipalities; however, its value is often overlooked. The urban forest contributes to energy savings, environmental benefits, psychological well-being, and social benefits. Managing the urban forest in a sustainable manner is important if we wish to benefit from these services well into the future. Reliable management techniques have been created through previous experiences with pests, and these should be utilized and improved for use on urban forests.

American elm (Ulmus americana L.) was once a major component of the urban forests of North America. In 1927, Dutch elm disease (DED) was …

New Approaches To Corn Silage Use In Beef Cattle Finishing Diets, Dirk B. Burken

Department of Animal Science: Dissertations, Theses, and Student Research

Cattle feeders are considering alternative feedstuffs to replace expensive corn grain and decrease rations costs. Feeding corn silage allows cattle feeders to take advantage of the entire corn plant at a time of maximum quality and tonnage as well as secure substantial quantities of roughage and grain inventory. Distiller’s grains have proven to be economical and are now a commonplace ingredient in feedlot finishing diets. Experiments were conducted to determine the effects of feeding increased concentrations of corn silage in replacement of corn grain in finishing diets containing distillers grains. Feedlot gains and gain:feed ratios were reduced as corn silage …

Beneficial Effects Of Simulated Gastro-Intestinal Digests Of Fried Egg And Its Fractions On Blood Pressure, Plasma Lipids And Oxidative Stress In Spontaneously Hypertensive Rats, Forough Jahandideh, Kaustav Majumder, Subhadeep Chakrabarti, Jude S. Morton, Sareh Panahi, Susan Kaufman, Sandra T. Davidge, Jianping Wu

Department of Food Science and Technology: Faculty Publications

Background: We have previously characterized several antihypertensive peptides in simulated digests of cooked eggs and showed blood pressure lowering property of fried whole egg digest. However, the long-term effects of this hydrolysate and its fractions on blood pressure are not known. Therefore, the objectives of the study were to determine the effects of long term administration of fried whole egg hydrolysate and its fractions (i.e. egg white and egg yolk) on regulation of blood pressure and associated factors in cardiovascular disease such as plasma lipid profile and tissue oxidative stress.

Methods and Results: We used spontaneously hypertensive rats (SHR), an …

Improving The Health Impacts Of Whole Grains Through Processing: Resistant Starch, Dietary Fiber Solubility, And Mineral Bioaccessibility, Jennifer A. Arcila Castillo

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Whole grains are good sources of starch, dietary fiber, and mineral elements. Starch is an important source of energy but also can be transformed to resistant starch to impart lower caloric value and increase total dietary fiber. Dietary fibers impart physiological benefits to human body once they are fermented by the gut microbiota. Mineral elements are important co-factors of a wide range of enzymes involved for instance in glucose and lipid metabolism. In general human body is capable of absorbing only 21-28% of most mineral elements, and gut bacteria are only able to ferment 34% of the dietary fiber from …

Metabolic Engineering Of Oilseed Crops To Produce High Levels Of Novel Acetyl Glyceride Oils With Reduced Viscosity, Freezing Point And Calorific Value, Jinjie Liu, Adam Rice, Kathleen Mcglew, Vincent Shaw, Hyunwoo Park, Thomas E. Clemente, Mike Pollard, John Ohlrogge, Timothy P. Durrett

Department of Agronomy and Horticulture: Faculty Publications

Seed oils have proved recalcitrant to modification for the production of industrially useful lipids. Here, we demonstrate the successful metabolic engineering and subsequent field production of an oilseed crop with the highest accumulation of unusual oil achieved so far in transgenic plants. Previously, expression of the Euonymus alatus diacylglycerol acetyltransferase (EaDAcT) gene in wild-type Arabidopsis seeds resulted in the accumulation of 45 mol% of unusual 3-acetyl-1,2- diacyl-sn-glycerols (acetyl-TAGs) in the seed oil (Durrett et al., 2010 PNAS 107:9464). Expression of EaDAcT in dgat1 mutants compromised in their ability to synthesize regular triacylglycerols increased acetyl-TAGs to 65 mol%. Camelina and soybean …

The Effect Of Weather During Rearing On Morphometric Traits Of Juvenile Cliff Swallows, Erin A. Roche, Mary Bomberger Brown, Charles R. Brown

School of Natural Resources: Faculty Publications

Episodes of food deprivation may change how nestling birds allocate energy to the growth of skeletal and feather morphological traits during development. Cliff swallows (Petrochelidon pyrrhonota) are colonial, insectivorous birds that regu­larly experience brief periods of severe weather–induced food deprivation during the nesting season which may affect offspring development. We investigated how annual variation in timing of rearing and weather were associated with length of wing and tail, skeletal traits, and body mass in juvenile cliff swallows reared in southwestern Nebraska during 2001–2006. As predicted under conditions of food deprivation, nestling skeletal and feather measurements were generally smaller …