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Retrospective Theses and Dissertations

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Porcine Reproductive And Respiratory Syndrome Virus: Understanding And Managing Persistent Infection, Ramón Miguel Molina Barrios Jan 2008

Porcine Reproductive And Respiratory Syndrome Virus: Understanding And Managing Persistent Infection, Ramón Miguel Molina Barrios

Retrospective Theses and Dissertations

This experiment was designed as a longitudinal study in which pigs were followed for up to 202 days post inoculation (DPI). On day 0, 109 3-week-old pigs were intramuscularly inoculated with PRRSV strain VR-2332. Negative control pigs (n = 56) were sham inoculated with MEM by the intramuscular route. Thereafter, at approximately 2-week intervals, samples were collected from all animals and a subset of randomly selected animals was euthanized and tissues collected. The presence and amount of virus was assessed using qRT-PCR, standard virus isolation, and bioassay. Detection of PRRSV in serum by qRT-PCR showed that most pigs cleared the viremia ...


Effect Of Genetic And Proteomic Variation In Field Isolates Of Mycoplasma Hyopneumoniae On Virulence, Diagnosis And Prevention Of Disease In The Pig, Erin Linn Strait Jan 2008

Effect Of Genetic And Proteomic Variation In Field Isolates Of Mycoplasma Hyopneumoniae On Virulence, Diagnosis And Prevention Of Disease In The Pig, Erin Linn Strait

Retrospective Theses and Dissertations

The purpose of these studies was to investigate the implications of variability in virulence, genetics and antigenic profiles among field isolates of Mycoplasma hyopneumoniae. Increased virulence was compared with in vitro and in vivo growth characteristics of the organism and with immune parameters in the pig, although none was found to be significantly correlated. The impact of proteomic and genetic variation among field isolates on diagnostic assays was examined by both in vivo and in vitro studies. Three enzyme-linked immunosorbent assays (ELISAs) used in the United States were compared and shown to not detect all isolates of M. hyopneumoniae equally ...


Analysis Of A Ddgs Air-Drying System With Heat Recovery, Christopher Brady Hoeck Jan 2008

Analysis Of A Ddgs Air-Drying System With Heat Recovery, Christopher Brady Hoeck

Retrospective Theses and Dissertations

Dry Distiller Grains with Soluble (DDGS) are a co-product of the conversion from corn into Ethanol fuel. Several applications depend on the ability of a drying process to remove moisture from a product, such as DDGS, in an effective and economical manner. Common drying methods use air to facilitate product drying as it proficiently absorbs the unwanted moisture, creating a moist-air mixture that captures both the latent and sensible heat released from the product. The most economical approach to an Air Drying System integrates a heat recovery system that transfers the heat removed by the moist-air mixture during drying back ...


The Land, It's Everything: Women Farmland Owners And The Institution Of Agricultural Conservation In The U.S. Midwest, Jean Crim Eells Jan 2008

The Land, It's Everything: Women Farmland Owners And The Institution Of Agricultural Conservation In The U.S. Midwest, Jean Crim Eells

Retrospective Theses and Dissertations

This institutional ethnography was undertaken to address the problematic that far fewer women than men participate in the institution of agricultural conservation despite the fact that about the same numbers of men and women own roughly equal amounts of agricultural land in the U.S. Midwest. The institution of agricultural conservation---governmental agencies and private non-profit organizations---provides conservation services such as technical assistance and funding to clients, private farmland owners, who implement conservation practices on their lands.;As a qualitative research methodology, institutional ethnography (IE) is a way to examine otherwise intractable or elusive problems that exist on an institutional level ...


Farmer Field Schools In Bungoma District Of Western Kenya: A Rapid Appraisal, Anthony Machacha Jan 2008

Farmer Field Schools In Bungoma District Of Western Kenya: A Rapid Appraisal, Anthony Machacha

Retrospective Theses and Dissertations

Africa has experienced the least socioeconomic progress in recent decades by many measures. Poverty, disease, drought, and conflict have combined to trap many nations in endless cycles of misery and plummeting quality of life. Agriculture, one potentially significant avenue out of these cycles and Africa's largest economic sector, is burdened with significant problems. Over the last five decades, various approaches to agricultural development have been introduced with some modest levels of success. The latest extension innovation in the fight against rural poverty is the Farmer Field School (FFS), introduced to Africa from South East Asia in the early 1990s ...


Functional Characterization Of Arabidopsis Sorting Nexin Atsnx2b, Nguyen Phan Jan 2008

Functional Characterization Of Arabidopsis Sorting Nexin Atsnx2b, Nguyen Phan

Retrospective Theses and Dissertations

Sorting nexins are conserved proteins that function in vesicular trafficking and are defined by the presence of a phox (PX) domain. Here we present the characterization of Arabidopsis thaliana sorting nexin AtSNX2b. The ubiquitously-expressed sorting nexin is a peripherally-associated membrane protein whose PX domain binds to phosphatidylinositol 3-phosphate in vitro. AtSNX2b localizes to the trans-Golgi network (TGN), prevacuolar compartment and endosomes. Overexpression of GFP-tagged AtSNX2b produces enlarged GFP-labeled compartments that can be also labeled by the endocytic tracer FM4-64, while untagged AtSNX2b overexpression generates compartments which are not as large. Endocytic trafficking of FM4-64 is arrested in cells overexpressing AtSNX2b ...


An Integrated Approach To Investigating The Reintroduction Of Flax Production In Iowa, Sarah Louise Carlson Jan 2008

An Integrated Approach To Investigating The Reintroduction Of Flax Production In Iowa, Sarah Louise Carlson

Retrospective Theses and Dissertations

The objectives of this research are a biological and sociological approach. These results will provide upper Midwestern, specifically Iowa, organic farmers with current, agronomic production guidelines from research conducted on-farm and on experiment stations, and to analyze the capability of these farmers to incorporate this alternative crop into their crop rotations. The effect of planting date, cultivar selection, planting rate, legume establishment, weed management strategies categorized as mechanical, chemical and biological: flax grain yield, straw biomass yield, total oil content, fatty acid profile, and underseeding and weed biomass production are analyzed. Additionally, straw quality characteristics were assessed.


Monitoring Vegetative Treatment System Performance For Open Beef Feedlot Runoff Control, Ishadeep Khanijo Jan 2008

Monitoring Vegetative Treatment System Performance For Open Beef Feedlot Runoff Control, Ishadeep Khanijo

Retrospective Theses and Dissertations

Vegetative treatment systems (VTS) are an alterative technology designed to control runoff from open beef feedlots. A VTS consists of a solids settling basin (SSB) followed by a vegetative treatment area (VTA) or a combination of vegetative infiltration basin (VIB) and a VTA. Four sites were monitored in 2006 and 2007 to evaluate the performance of the VTSs in Iowa. In 2006, the percent runoff control at Central IA 1 & 2 and Northwest IA 1 & 2 was measured as 99, 74, 96, and 98 respectively. In 2007, the SSB outlets were actively managed and the percent runoff control at Central ...


Postconflict And Conflict Behavior In All-Male Groups Of Captive Western Lowland Gorillas (Gorilla Gorilla Gorilla), Jackie Elizabeth Davenport Jan 2008

Postconflict And Conflict Behavior In All-Male Groups Of Captive Western Lowland Gorillas (Gorilla Gorilla Gorilla), Jackie Elizabeth Davenport

Retrospective Theses and Dissertations

I studied male western lowland gorillas (Gorilla gorilla gorilla) in a captive setting in order to determine if post-conflict reconciliation exists in male-male dyads of this species. I also examined conflict itself in order to determine the consequences of housing these males together in all-male groups in captivity. This was accomplished by examining the behaviors of nine male gorillas at the Henry-Doorly Zoo in Omaha, Nebraska. Data that I recorded included post-conflict observations, social interactions, and activity budgets. I analyzed the data in order to determine levels of reconciliation, welfare of the population, and comparisons with wild conspecifics. I hypothesized ...


A Negative Regulator Of Ribosomal Rna Processing Specifies R-Gene-Independent Cell Death In Barley - Powdery Mildew Interactions, Liu Xi Jan 2008

A Negative Regulator Of Ribosomal Rna Processing Specifies R-Gene-Independent Cell Death In Barley - Powdery Mildew Interactions, Liu Xi

Retrospective Theses and Dissertations

Programmed Cell Death (PCD) plays a pivotal role in plant development and defense. Pathogen dependent cell-death mutants were used to investigate the complex regulatory pathways between PCD and R-gene mediated resistance. Time-course expression profiles of Blumeria graminis f. sp. hordei (Bgh) challenged C.I. 16151 (harboring the Mla6 powdery mildew resistance allele) and its fast-neutron-derived "Bgh-induced tip cell death1" mutant, bcd1, were compared using the 22K Barley1 GeneChip. Contrasts were made to identify genes associated with the cell death phenotype as opposed to R-gene mediated resistance. One hundred eighty-two genes were found in the intersection of these contrasts at a ...


Comparison Of Carcass Composition, Performance, And Tissue Deposition Rates Among Breeds Of Swine, Bryce David Martin Jan 2008

Comparison Of Carcass Composition, Performance, And Tissue Deposition Rates Among Breeds Of Swine, Bryce David Martin

Retrospective Theses and Dissertations

A study was conducted to evaluate differences in performance, carcass traits, and tissue deposition rates among breeds of swine entered in the 2003 National Barrow Show Progeny Test. The test consisted of 362 barrow and gilt progeny from sires within each of the 8 breeds evaluated. Breeds tested were Berkshire (n = 158), Duroc (n = 76), Chester White (n = 53), Yorkshire (n= 31), Spotted (n = 15), Landrace (n = 15), Poland (n = 8), and Hampshire (n = 6). Due to small sample size, the Spotted, Landrace, Poland, and Hampshire breeds were combined in an All Other Breeds (AOB) category. Progeny were weighed and ...


Relationship Of Centrally-Located Body Fat To Appetitive Hormones In Healthy Postmenopausal Women, Laura Marie Ritland Jan 2008

Relationship Of Centrally-Located Body Fat To Appetitive Hormones In Healthy Postmenopausal Women, Laura Marie Ritland

Retrospective Theses and Dissertations

Objective. Body composition and energy homeostasis are thought to affect the appetitive hormones: adiponectin, leptin, insulin, and ghrelin. This study examined whether centrally-located fat and/or overall adiposity were related to these appetitive hormones in healthy postmenopausal women.;Design. Overall and regional body composition was assessed by dual-energy X-ray absorptiometry in relation to plasma adiponectin, serum leptin, serum insulin, and plasma ghrelin in 242 postmenopausal women.;Results. Regression analyses revealed that the androidal-to-gynoidal fat mass ratio (18.0%), age (3.2%), and white blood cell count (1.8%) accounted for 28% of the variability in adiponectin (F=22.2; P ...


Use Of Fourier Transform Infrared (Ftir) Spectroscopy To Determine The Health-Promoting Index (Hpi) Of Cow's Milk, Wendy Leanne Thomas Jan 2008

Use Of Fourier Transform Infrared (Ftir) Spectroscopy To Determine The Health-Promoting Index (Hpi) Of Cow's Milk, Wendy Leanne Thomas

Retrospective Theses and Dissertations

Fourier transform infrared (FTIR) spectroscopy steadily has been gaining popularity for the analysis of milk components including total fat, protein, lactose, and ketones. To date, there have been few descriptions of the use of FTIR spectroscopy for the determination of milk fatty acid composition.;The first objective of this thesis was to develop a method utilizing FTIR spectroscopy for prediction of the health-promoting index (HPI) of milk. The HPI is known to affect the relative softness of butter (Bobe et al., 2003); so, this model could be used to predict which cows' milk could be designated for generation of niche ...


Accumulation Of Bel1-Like Transcripts In Solanaceous Species, Brian Anthony Campbell Jan 2008

Accumulation Of Bel1-Like Transcripts In Solanaceous Species, Brian Anthony Campbell

Retrospective Theses and Dissertations

Although numerous RNAs have been detected in the phloem, few have been confirmed to move long distances. In potato, full-length mRNA of the BEL1-like transcription factor, StBEL5, moves from leaf veins through the phloem to stolon tips to activate tuber formation. BEL1-like transcription factors are ubiquitous in plants and interact with KNOTTED1-types to regulate numerous developmental processes. To explore the range of KNOTTED1- and BEL1-like mRNAs present in phloem, an analysis of the transcript profile of phloem sap was undertaken. Using a modified technique for the collection of phloem-enriched exudate from excised stems, numerous RNAs encoding these transcription factors were ...


Terrestrial Arthropod Community And Indicators Of Biotic Integrity For Iowa Tallgrass Prairie, Jessica Marie Orlofske Jan 2008

Terrestrial Arthropod Community And Indicators Of Biotic Integrity For Iowa Tallgrass Prairie, Jessica Marie Orlofske

Retrospective Theses and Dissertations

The tallgrass prairie has become one of the most endangered ecosystems in North America. Thus, there have been attempts to restore and reconstruct native tallgrass prairie. Arthropods, the most diverse taxonomic group on the prairie, have not received adequate attention. A comprehensive arthropod survey in Iowa prairies has not been attempted since the 1930's, and therefore lacks information regarding recent prairie restoration efforts. Arthropods can also provide valuable information related to ecosystem function or biotic integrity when used as bioindicators. However, effective, reliable arthropod bioindicators have not been clearly identified. A survey of arthropods using sweep net transects was ...


Ecology Of Elk Parturition Across Winter Feeding Opportunities In The Brucellosis Endemic Area Of Wyoming, Andrea Ellen Barbknecht Jan 2008

Ecology Of Elk Parturition Across Winter Feeding Opportunities In The Brucellosis Endemic Area Of Wyoming, Andrea Ellen Barbknecht

Retrospective Theses and Dissertations

This study was initiated to examine parturition related behavior both from an ecological perspective and to investigate implications for brucellosis transmission risk among elk and between elk and cattle. These aspects were investigated for elk fed during the winter, elk using improved winter feedlines, and free-ranging elk. Brucellosis is a disease causing abortion in elk ( Cervus elaphus nelsoni), bison (Bos bison), and cattle (Bos spp.). The most common transmission route is through oral contact with aborted fetuses or parturition tissues/fluids and transmission risk is dependent on contact rates. Vaginal implant transmitters were deployed on winter free-ranging elk and elk ...


Quantitative Studies On Airborne Transmission Of Porcine Reproductive And Respiratory Syndrome Virus, Joseph Ralph Hermann Jan 2008

Quantitative Studies On Airborne Transmission Of Porcine Reproductive And Respiratory Syndrome Virus, Joseph Ralph Hermann

Retrospective Theses and Dissertations

Porcine reproductive and respiratory syndrome virus (PRRSV) is an enveloped RNA virus in the family Arteriviridae within the order Nidovirales (Cavanagh, 1997).;The objective of the first study was to optimize sampling parameters for increased recovery and detection of airborne PRRSV and swine influenza virus (SIV). Collection media containing antifoams, activated carbons, protectants, and ethylene glycol were evaluated for direct effects on factors impacting the detection of PRRSV and SIV, including virus infectivity, viability of continuous cell lines used for the isolation of these viruses, and performance of reverse-transcriptase polymerase chain reaction (RT-PCR) assays. The results showed that specific compounds ...


A Simulation Assessment Of The Boone River Watershed: Baseline Calibration/Validation Results And Issues, And Future Research Needs, Philip Walter Gassman Jan 2008

A Simulation Assessment Of The Boone River Watershed: Baseline Calibration/Validation Results And Issues, And Future Research Needs, Philip Walter Gassman

Retrospective Theses and Dissertations

A SWAT modeling framework has been constructed for the Boone River Watershed (BRW) in north central Iowa, to support further testing of SWAT and analyses of alternative management practice and/or cropping system scenarios. The BRW covers over 237,000 ha and is an intensively cropped region dominated by corn and soybean production. Nitrate losses are of particular concern in the BRW, especially through subsurface tiles that drain the predominantly flat landscapes that persist throughout the watershed. The modeling system features an intensive set of management, land use, and soil data developed at the Common Land Unit (CLU) level. The ...


Understanding Protein Motions By Computational Modeling And Statistical Approaches, Lei Yang Jan 2008

Understanding Protein Motions By Computational Modeling And Statistical Approaches, Lei Yang

Retrospective Theses and Dissertations

Because of its appealing simplicity, the elastic network model (ENM) has been widely accepted and applied to study many molecular motion problems, such as the molecular mechanisms of chaperonin GroEL-GroES function, allosteric changes in hemoglobin, ribosome motions, motor-protein motions, and conformational changes in general. In this dissertation, the ENM is employed to study various protein dynamics problems, and its validity is also examined by comparing with experimental data. First, we apply principal component analysis (PCA) to identify the essential protein motions from multiple structures (X-ray, NMR and MD) of the HIV-1 protease. We find significant similarities between the first few ...


Three Essays On Agricultural Risk And Insurance, Li Zhang Jan 2008

Three Essays On Agricultural Risk And Insurance, Li Zhang

Retrospective Theses and Dissertations

The general theme of this dissertation is agricultural risk and insurance in the United States. Chapter 2 examines welfare effects of the 2002 farm bill programs and yield insurance as well as their impacts on acreage decision of a representative Iowa farmer. Instead of measuring welfare using expected utility to capture farmers' preferences over risky alternatives, we apply recent advances in decision theory and use prospect theory to measure welfare changes due to government programs. The results indicate that there is no policy distortion to farmers' acreage decisions and farmers' willingness to pay per dollar of program cost is greatest ...


Genetic Mapping And Analysis Of Traits Related To Improvement Of Popcorn, Thanda Dhliwayo Jan 2008

Genetic Mapping And Analysis Of Traits Related To Improvement Of Popcorn, Thanda Dhliwayo

Retrospective Theses and Dissertations

Popcorn and dent maize are distinct gene pools and are maintained and utilized as such in maize breeding programs. Popcorn is inferior to dent maize in traits related to crop productivity. Dent maize is a potential source of favorable alleles to improve the productivity of popcorn, but its utility is hindered by dent alleles with negative effects on popping expansion volume (PEV). If the genetic architecture of popping expansion and other important traits is known in dent x popcorn populations, the negative effects of dent germplasm on PEV may be minimized by marker-assisted selection. Use of DNA markers in breeding ...


Nutrient Recycling In Biofuel Production Systems: Biomass Ash Pelleting, Ethanol Co-Product Allocation, And A Beef-Ethanol Production System Analysis, Katherine A. Edwards Jan 2008

Nutrient Recycling In Biofuel Production Systems: Biomass Ash Pelleting, Ethanol Co-Product Allocation, And A Beef-Ethanol Production System Analysis, Katherine A. Edwards

Retrospective Theses and Dissertations

Relative to fossil fuels, biofuels help to close the carbon cycle; however other essential nutrient cycles remain open. When biomass is removed from the agricultural landscape for biofuel production, essential plant nutrients such as nitrogen (N), phosphorus (P), and potassium (K) are also removed and concentrate in biorefinery waste streams and low value co-products. This thesis comprises three analyses related to nutrient cycles in the emerging bioeconomy. In the first, combusted biomass ash was pelleted and evaluated as a potential fertilizer. In the second, an energy co-product credit for corn dry grind ethanol production has been determined by examining the ...


Studies On The Vector Competence Of A Mid-Western Strain Of Aedes Vexans (Meigen) (Diptera: Culicidae) For West Nile Virus, Jason Robert Kinley Jan 2008

Studies On The Vector Competence Of A Mid-Western Strain Of Aedes Vexans (Meigen) (Diptera: Culicidae) For West Nile Virus, Jason Robert Kinley

Retrospective Theses and Dissertations

Aedes vexans (Meigen) mosquitoes were given access to 2- to 4-day-old chickens inoculated with 103.0 CID50s/ml West Nile Virus (WNV) at 1 day old. Mosquitoes were given access to chickens at different intervals after inoculation to make certain that blood meals were of varying virus titers. No differences occurred in infection rates of Ae. vexans and Culex pipiens (L.) fed on the same WNV viremic chicken. Infection rates of Ae. vexans were higher when fed on chickens with viremias of 6.0 log10 WNV PFUs/ml or higher than they were in mosquitoes fed on chickens with viremias ...


Grassland Bird Abundance And Nesting In Short-Duration Rotationally Grazed Pastures In Southwest Iowa, Ryan David Marquardt Jan 2008

Grassland Bird Abundance And Nesting In Short-Duration Rotationally Grazed Pastures In Southwest Iowa, Ryan David Marquardt

Retrospective Theses and Dissertations

Grassland bird populations across the Midwest are experiencing declines due to loss of habitat, which could potentially be replaced with grazing systems. This study measured abundance, nesting, and derived conservation values for a rotational stocking grazing management unit where cool-season grass (CSG) paddocks were grazing in the spring and fall and rested in the summer, and warm-season grass (WSG) paddocks were grazed in the summer and rested in spring an fall. Adjacent ungrazed Conservation Reserve Program lands in CSG and WSG served as control treatments. Dickcissels (Spiza americana ) had bird densities in ungrazed WSG fields (3.8+/-0.29 birds ...


Protein Kinase C-Delta In Dopaminergic System And Experimental Models Of Parkinson's Disease, Danhui Zhang Jan 2008

Protein Kinase C-Delta In Dopaminergic System And Experimental Models Of Parkinson's Disease, Danhui Zhang

Retrospective Theses and Dissertations

Parkinson's disease (PD) is a major neurodegenerative disorder characterized by progressive and substantial loss of dopaminergic neurons in the substantia nigra compacta (SNc). Currently, no available drugs prevent the progressive loss of nigral dopaminergic neurons. The mechanisms underlying the dopaminergic degenerative process observed in PD are not well understood, which has hampered development of successful neuroprotective drugs. Tyrosine hydroxylase (TH) is the rate-limiting enzyme in dopamine synthesis. Severely reduced TH positive neurons and TH fibers in dopaminergic terminal fields of PD patients and the successful application of L-DOPA therapy for Parkinson's disease suggest that this enzyme has a ...


Analysis On Protein Structures Using Statistical And Bioinformatical Methods, Aimin Yan Jan 2008

Analysis On Protein Structures Using Statistical And Bioinformatical Methods, Aimin Yan

Retrospective Theses and Dissertations

This PhD dissertation mainly focuses on the statistical analysis for the protein structure data. The first research project focuses on data mining and prediction for side chain orientation in protein structure. Through this study, we find that the general side chain orientation can be viewed as a manifestation of hydrophobic force. Along with this study, we also developed the software for visualizing the general side chain vector and applied statistical machine learning methods to fit several models for predicting general side chain orientation. In the second project, we studied the motion of partially assembled ribosome 30S subunit using the coarse-grained ...


A Genomic Study Of Soybean Iron Deficiency Chlorosis, Jamie Aileen O'Rourke Jan 2008

A Genomic Study Of Soybean Iron Deficiency Chlorosis, Jamie Aileen O'Rourke

Retrospective Theses and Dissertations

Soybeans grown in the farmlands of the upper Midwest of the United States often suffer from iron deficiency chlorosis which results in end of season yield loss. Previous studies in soybean have identified 19 Quantitative Trait Loci (QTL) regions with an association to iron deficiency chlorosis. However, specific genes involved in the process of iron reduction, uptake and transport have not been identified in soybean. Through the use of near isogenic soybean lines (NILs), Expressed Sequence Tag (EST) microarrays, and Affymetrix RTM GeneChipsRTM, I have identified a suite of candidate genes putatively involved in the soybean iron deficiency response. Single ...


Exploring Host-Pathogen Relationships Through Computer Simulations Of Intracellular Infection, Garrett Marc Dancik Jan 2008

Exploring Host-Pathogen Relationships Through Computer Simulations Of Intracellular Infection, Garrett Marc Dancik

Retrospective Theses and Dissertations

Computer simulations of infectious disease allow for the identification and estimation of important pathogen and immune parameters, the validation of theoretical biological models with experimental data, and the characterization of the host-pathogen interactions that lead to emergent and sometimes counterintuitive behavior. This thesis describes the development, analysis, and calibration of a computer model of Leishmania major infection, the identification of correlates of escape mutant success and optimal escape strategies in a computer model of a viral infection, and statistical software to aid in computer model analysis and calibration.;In an agent-based model of L. major infection, sensitivity analysis reveals that ...


The Use Of Genetic Markers To Improve Sow Productive Life And Genetic Abnormalities, Benny Edd Mote Jan 2008

The Use Of Genetic Markers To Improve Sow Productive Life And Genetic Abnormalities, Benny Edd Mote

Retrospective Theses and Dissertations

The driving force behind using molecular genetics in livestock selection programs is to improve the profitability of not only the genetic supplier but also their customers using the product. Traditional quantitative genetics have greatly helped the geneticists improve traits with higher heritabilities, but there is still room for advancements, especially in traits that are measured late in life, measured in only one sex, and traits with lower heritabilities. Two such traits that could benefit from the identification and use of molecular markers are genetic defects and sow reproductive life, or the length of time that a sow remains productive in ...


Phyllosphere-Mediated Bacterial Degradation Of Airborne Phenol, Amarjyoti Sandhu Jan 2008

Phyllosphere-Mediated Bacterial Degradation Of Airborne Phenol, Amarjyoti Sandhu

Retrospective Theses and Dissertations

Bacterial degradation of organic pollutants in soil has been studied extensively but little is known about the availability and degradation of pollutants by bacterial resident on leaf surfaces. Here, we examined availability and degradation of phenol on leaves by introduced cells of a known phenol degrader and by natural microbial communities. Phenol-responsive gfp-expressing Pseudomonas fluorescens A506 bioreporter cells detected airborne phenol as well as phenol that had been adsorbed by leaf surfaces. The degradation of airborne 14C-phenol by leaf-associated bacteria showed that Pseudomonas sp. strain CF600 released eight times more 14CO2 than a non-degrading mutant after introduction onto leaves. This ...