Understanding And Developing Safer Sanitation Agents And Strategies In Food Production Environments, Pragathi Kamarasu

Doctoral Dissertations

Food is a primary resource for survival of human beings, and it is also one of the primary resources for spread of infectious diseases. When both these factors come together it does not only cause ill effects on our health but also causes a burden on the food and agricultural industry. Through the help of science, us researchers and scientists have always tried to reduce this burden. And I hope like a drop of water in the ocean in some way my research contributes towards this. According to WHO currently in 2023 there are about 1 in 10 people falling …

Increasing Productivity And Biodiversity Of Tall Fescue Swards By Intercropping Cool And Warm-Season Forage Species, Michael Dereck Corbin

Doctoral Dissertations

Mixed pastures are known to produce greater biomass yields and higher nutritive value than monocultures. Intercropping biologically N fixating legumes, along with the use of intercropping warm-season annual grasses, such as crabgrass [Digitaria ciliaris Retz.], provides the potential to aid tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.] productivity. To determine the benefits of intercropping species into tall fescue forage systems in the Southeastern U.S., two studies were developed. The first study consisted of 9 tall fescue paddocks, in which 3 paddocks contained red clover (Trifolium pratense L. [TRC]) mixed with tall fescue, 3 paddocks contained sunn …

Role Of Plasma Membrane Intrinsic Proteins (Pips) Subfamily And Sulfur Nanoparticle Interactions In Metalloids Transport And Tolerance/Sensitivity In Rice, Ahmed Gm Ali

Doctoral Dissertations

Plasma membrane intrinsic proteins (PIPs) are major intrinsic proteins (MIPs) with the ability to permeate water and small uncharged solutes as well as metalloids including arsenic (As), through the cell membranes. Arsenic is a highly toxic element that occurs naturally in the earth's crust or from anthropogenic activities with a severe poisonous effect on most living organisms. Rice, as the daily staple food for more than half of the world population, accumulates higher As contents than any other economic crop due to its growing conditions in flooded paddy fields. Members from the NOD26-like intrinsic proteins (NIP) subfamily of MIP were …

Corn (Zea Mays L.) Production In Living Mulch Systems, Grazing Potential, And Economic Viability, Marcia Peireira Quinby

Doctoral Dissertations

Living mulch (LM) is a practice in which forages are grown simultaneously with the main crop, serving as a living cover throughout the growing season. The LM systems were developed to alleviate concerns of soil depletion and finding ways to reduce tillage negative effects on soil productivity. In addition, when legumes are use can decrease the reliance on N fertilizer. The use of corn in LM have been previously studied due to the crop being a large commodity in the U.S.; In addition, the ability to graze the LM after corn production can increase the land use efficiency. To determine …

Poa Annua: An Annual Species?, Devon E. Carroll

Doctoral Dissertations

Poa annua L. is ranked the most troublesome turfgrass weed but can also be a highly desirable turfgrass species. As the Latin name annua implies, the species is thought to persist via an annual life cycle; yet there are many reports in literature of P. annua persisting perennially. Considering that P. annua senescence patterns do not align with other true annual species such as Triticum spp. and Zea mays L., we hypothesized that P. annua presents itself similarly to other perennial, cool-season, turfgrass species that are subject to a confluence of environmental factors in summer that can cause mortality. …

Community Assembly And Stress Response Of Grassland Phyllosphere Bacteria, Emily Bechtold

Doctoral Dissertations

Grasslands are an important ecosystem with potential to help stabilize food security and reduce greenhouse gas levels. As global temperatures rise, weather patterns are predicted to drastically change. The resulting increase in intensity, duration, and frequency of drought in important grassland areas will not only affect agricultural production, but also increase grassland susceptibility to fire, disease, and soil erosion. Thus, developing ways to sustainably promote grassland health and production is essential to increase food security and reduce environmental strain. Microbes in the phyllosphere, or aerial surface of plants, promote host fitness through phytohormone and nutrient production, increased stress tolerance, and …

Impacts Of Soil Management On Microbial Assemblages Involved In Nitrogen Transformations In Agroecosystems In Tennessee, Usa, Jialin Hu

Doctoral Dissertations

Nutrient reduction, particularly with respect to nitrogen (N) losses, is an important goal for sustainably managed agroecosystems. Soil N-cycling microbial populations that modulate these processes are affected by agricultural management regimes. This research focused on the controls and dynamics of the major N-cycling microbial populations in high-input cotton field under agricultural management regimes and low-input native C₄ forage grass systems under pasture management practices to determine the effects of management regimes on in situ seasonal dynamics of the functional microbes responsible for N fixation, nitrification, and denitrification processes. Molecular microbial ecology methods were combined with soil physicochemical properties and …

Characterization And Management Of Glyphosate-Resistant Junglerice, Clay M. Perkins

Doctoral Dissertations

Junglerice has become a major weed in Tennessee and across the mid-south. Glyphosate resistance and dicamba antagonism has resulted in the reported control failures and rise in prevalence. Junglerice was the most prevalent weed escape in cotton and soybean fields across Tennessee from 2018 to 2020. In all, 13% of the junglerice accessions could no longer be effectively controlled with glyphosate. Due to poor in-crop control, it has been recommended to start clean when trying to control junglerice and other grasses. Therefore, research was conducted to determine the best burndown methods utilizing dicamba, glufosinate, or paraquat. A sequential application of …

Exposure Assessment Of Emerging Contaminants: Rapid Screening And Modeling Of Plant Uptake, Majid Bagheri

Doctoral Dissertations

"With the advent of new chemicals and their increasing uses in every aspect of our life, considerable number of emerging contaminants are introduced to environment yearly. Emerging contaminants in forms of pharmaceuticals, detergents, biosolids, and reclaimed wastewater can cross plant roots and translocate to various parts of the plants. Long-term human exposure to emerging contaminants through food consumption is assumed to be a pathway of interest. Thus, uptake and translocation of emerging contaminants in plants are important for the assessment of health risks associated with human exposure to emerging contaminants. To have a better understanding over fate of emerging contaminants …

Effects Of Fertilization And Drying Conditions On The Quality Of Selected Chinese Medicinal Plants, Zoe Gardner

Doctoral Dissertations

Demand for Chinese medicinal herbs in the U.S. is increasing and American acupuncturists and farmers are interested in domestic production of these plants. Little is known about the feasibility of production of these species outside of China. Four species of herbs were selected for cultivation trials. The purposes of this research were to evaluate the feasibility of cultivation of these species in the northeastern United States, to develop basic agronomic data for each species, and to determine the effects of nitrogen fertilizer on plant growth, yield, and secondary metabolites. Agastache rugosa, Schizonepeta tenuifolia, Leonurus japonicus, and Leonurus …

Surface-Enhanced Raman Spectroscopic Imaging Of Bacteria Within Fresh Produce In Situ, Michael Hickey

Doctoral Dissertations

The growth curves for E. coli O157:H7 (#043888) are reported. We make the case that the onset of stationary growth is the optimal point at which a bacteria culture is considered suitable for quantitative Raman analyses. The optimal conditions for 3-mercaptophenylboronic acid coating of bacteria cells is also reported. Fundamental drawbacks of the status-quo approach have been elucidated and overcome, based on measurable improvements to the experimental methodology. This approach is shown to be suitable for the evaluation of bacterial rinse-washing efficacy by means of Raman light-scattering. The data were compared to label-free applications and the measurable differences between each …

The Good, The Bad, And The Ugly: Pollinators As Vectors Of Mummy Berry Disease In Highbush Blueberry, Matthew Boyer

Doctoral Dissertations

Background: Many plants must balance the need for pollination services with mediating the risk of pollinator-vectored pathogens. Vaccinium corymbosum, highbush blueberry, is negatively affected by an insect-vectored, fungal plant pathogen, Monilinia vaccinii-corymosi (MVC), the cause of mummy berry disease, in which the asexual spore mimics pollen grains and is transferred from blighted tissue to flowers via pollinators, resulting in inedible, hardened fruits. Highbush blueberry plants require outcrossed pollen for maximum yield and fecundity. Therefore, yield of blueberry plants rely on a balance between adequate pollination service and disease avoidance. Approach: To explore the relationship between pollinator community and infection …

Combination Regimens Using Dietary Components For The Chemoprevention Of Colorectal Cancer And Inflammation, Christina Dimarco-Crook

Doctoral Dissertations

ABSTRACT COMBINATION REGIMENS USING DIETARY COMPONENTS FOR THE CHEMOPREVENTION OF COLORECTAL CANCER AND INFLAMMATION September 2018 CHRISTINA DIMARCO-CROOK, B.S., IMMACULATA UNIVERSITY M.S., DREXEL UNIVERSITY Ph.D., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Hang Xiao Dietary components have been found to effectively modulate multiple deregulated signaling pathways associated with the initiation and progression of carcinogenesis and inflammation in cellular and animal models. However, clinical studies have shown mixed results when examining the efficacy of individual dietary components, perhaps suggestive of the synergism that exists between multiple components within a particular food and the diet as a whole. Additional research is needed …

Golfer Exposure To Pesticides, Jeffery Doherty

Doctoral Dissertations

There is concern among industry regulators, turfgrass managers, and the general public over human exposure to pesticides following their application to turfgrass. The residential aspect of turfgrass applications raises concerns about exposure to infants and children, as well as adults. To accurately determine the exposure of golfers to turfgrass pesticides, it is necessary to understand their transfer and absorption dynamics, as well as the routes of golfer exposure. Previous research has demonstrated that exposure to some turfgrass pesticides is at a level that would concern USEPA risk assessors using the USEPA Hazard Quotient (HQ) criteria (1). This current research used …

All Roads Lead To Weediness: Stories About Weedy Rice Origins, Weedy Genes And Weed Competitiveness, Zhongyun Huang

Doctoral Dissertations

Weedy rice (Oryza spp.), a weedy relative of cultivated rice (O.sativa), infests and persists in cultivated rice fields worldwide. Many weedy rice populations have evolved similar adaptive traits, considered part of the ‘agricultural weed syndrome’, making this an ideal model to study the genetic basis of parallel evolution. Using population genetics analyses of South Asian and US weedy rice, my research reveals multiple independent evolution events giving rise to weed groups in the two geographic areas. Weeds in South Asia have highly heterogenous genetic backgrounds, with contributions from both cultivated varieties (aus and indica) …

Identification Of Molecular Mechanisms Of Resistance To Transgenic Maize Producing The Cry1fa Protein In Different Spodoptera Frugiperda Populations, Rahul Banerjee

Doctoral Dissertations

The use of transgenic maize event TC1507 producing the Cry1Fa insecticidal protein from the bacterium Bacillus thuringiensis has been very useful to control the target lepidopteran insect pest Spodoptera frugiperda. The extensive use of this transgenic maize event resulted in high selection pressure for development of Cry1Fa resistance in field insects in multiple locations, including Brazil, Puerto Rico and the southeastern USA. Resistance developed in Puerto Rico was characterized in the 456LS3 strain originated from that island as monogenic, autosomal recessive and associated with reduced expression of a membrane bound alkaline phosphatase (SfmALP2). Currently, we focused on identifying the …

Modification Of Carbohydrate Active Enzymes In Switchgrass (Panicum Virgatum L.) To Improve Saccharification And Biomass Yields For Biofuels, Jonathan Duran Willis

Doctoral Dissertations

The natural recalcitrance of plant cell walls is a major commercial hurdle for plant biomass to be converted into a viable energy source as alternative to fossil fuels. To circumvent this hurdle manipulation of carbohydrate enzymes active in the cellulose and hemicellulose portions of the plant cell wall can be utilized to improve feedstocks. Production of cellulolytic enzymes by plants have been evaluated for reducing the cost associated with lignocellulosic biofuels. Plants have successfully served as bioreactors producing bacterial and fungal glycosyl hydrolases, which have altered plant growth to improve saccharification. A bioprospecting opportunity lies with the utilization of insect …

Novel Advancements For Improving Sprout Safety, Kyle S. Landry

Doctoral Dissertations

All varieties of bean sprouts (mung bean, alfalfa, broccoli, and radish) are classified as a “super-food” and are common staples for health conscious consumers. Along with the proposed health benefits, there is also an inherent risk of foodborne illness. When sprouts are cooked, there is little risk of illness. The purpose of this dissertation was to explore novel techniques to minimize or prevent the incidence of foodborne illness associated with the consumption of sprouts. Three areas were investigated: 1) the use of a biocontrol organism, 2) the use of a novel spontaneous carvacrol nanoemulsion, and 3) the influence of the …

Cover Crop And Nitrogen Fertilizer Management For Potato Production In The Northeast, Emad Jahanzad

Doctoral Dissertations

Potato (Solanum tuberosum L.) rates fourth among the world’s agricultural products in terms of production volume and human consumption and worldwide demand for potatoes will exceed that of rice, wheat, or corn by 2020. Potato consumption has been a major part of the North American diet since early in the 17^th century and as a dominant arable crop in the Northeastern United States. There are over 2700 potato fields in the Northeast United States and potato growers often over apply nitrogen (N) fertilizer to ensure against loss of yield. High mobility of nitrate form N fertilization in the …

Effects Of Overexpression Of Sap12 And Sap13 In Providing Tolerance To Multiple Abiotic Stresses In Plants, Parul R. Tomar

Doctoral Dissertations

Environmental stresses are the one of the main reasons for the decline of crop production worldwide. In the past years, a major focus has been on improving plant species and their tolerance towards these stresses but not much has been achieved because of the limited knowledge of the gene/network of genes that might be involved in providing tolerance to such multiple abiotic stresses. Recently, members of Stress Associated Protein (SAP) family in plants have been shown to impart tolerance to multiple abiotic stresses. There are 14 SAP genes in Arabidopsis thaliana and these proteins contain A20, AN1 and C2H2 zinc …

Evaluation Of Leafy Green Species Popular Among Ethnic Groups For Production And Markets In The Northeastern Usa, Ricardo A. Orellana

Doctoral Dissertations

ABSTRACT

Salmonella In Low Water Activity Foods: Physiological, Genetic Modification And Control Methods, Wei Chen

Doctoral Dissertations

The objective of this study was to evaluate the expression of fatty acid associated genes (fabA, fabD and cfa) of five serovars of Salmonella exposed to sugar over a 14-day period. Changes in the fatty acid composition of Salmonella Tennessee in glycerol solutions of different water activity (a_w) (1.0-0.6) and the relationship between survival and fatty acid modification (as altered by exogenously supplied fatty acids) at a_w 1.0-0.6 were also determined. Furthermore, the antimicrobial activities of carvacrol, cinnamaldehyde, and lauric arginate (LAE) alone or in combination against Salmonella Tennessee in a laboratory model of …

Characterization Of The Role Of Alpha-Arylphorin In The Heliothis Virescens Midgut Response To Cry1ac Toxin From Bacillus Thuringiensis, Jerreme Jamael Jackson

Doctoral Dissertations

Homeostasis of the intestinal epithelium in Heliothis virescens is mediated by the proliferation and differentiation of multipotent intestinal stem cells (ISCs) that lie adjacent to the basal lamina. In response to extrinsic and intrinsic signals, ISC proliferation and differentiation promotes epithelial growth and regeneration following the loss of integrity. We tested the in vivo effects of the ISC mitogen, a [alpha]-arylphorin, on ISC proliferation and the morphological changes of the midgut during larval development. Additionally, we examined how these changes affected the intestinal epithelium response to Cry1Ac toxin from Bacillus thuringiensis. Histological and in vitro evidence supported two distinct …

Identification And Confirmation Of Quantitative Trait Loci For Protein Concentration And Improved Amino Acid Composition In Glycine Max, Jeneen Samantha Abrams

Doctoral Dissertations

The demand for poultry and swine production has grown continually as the world population increases. There will be an estimated 8 billion people to feed in the world by 2025. Soybean meal is the most important plant protein ingredient for poultry and swine feedstock. Globally, the US produces 32% of the world’s soybean. Although soymeal is nearly a complete plant protein, it is highly supplemented with sulfur-containing amino acids such as cysteine and methionine. The objectives of this project were to utilize molecular markers known as single nucleotide polymorphisms (SNPs) to identify genomic regions associated with protein concentration and amino …

Production, Marketing, And Handling Practices To Export Mcintosh Apples To Central American Markets, Mildred L. Alvarado Herrera

Doctoral Dissertations

Latin America offers a marketing opportunity for fresh produce, since many countries are entering into global integration and international trade as part of their portfolio of economic growth. However, to take full advantage of these opportunities, many questions associated with the implementation of marketing approaches, fresh produce quality retention, and profitability need be answered before undertaking this business opportunity. When it comes to developing countries such as those in Central America, and in particular - El Salvador, Honduras, and Guatemala - language, culture, technology, competitiveness, regulations, poverty, and other barriers become challenges to enter these markets successfully. In order to …

World Wide Diversity Of Phytophthora Capsici, Dylan B. Storey

Doctoral Dissertations

The plant pathogen Phytophthora capsici is a genetically diverse organism that is a global problem. It effects many crops across the Solanacea, Cucurbitacea, andLeguminosea. As a result of the large diversity between individuals (and by extension populations) it has been previously near impossible to make meaningful comparisons between individuals of geographically distinct locations. Here we present the results of applying Next Generation Sequencing (NGS) technologies to a representative panel of isolates. This information and data is further used to demonstrate how this diversity has a functionally relevent effect on a class of proteins responsible for the infectious process. We …

Characterization Of Field Evolved Resistance To Transgenic Cry1fa Maize In Spodoptera Frugiperda (J. E. Smith), Siva Rama Krishna Jakka

Doctoral Dissertations

Transgenic Bt crops expressing Cry and Vip toxins from Bacillus thuringiensis (Bt) have been increasingly planted to manage insect pest damage on agricultural crops. The high adoption of Bt-based insecticidal technologies suggests an increase selection pressure for the evolution of resistance in insect populations. So far, nine insect species have developed field evolved resistance to Bt crops, yet the mechanisms involved in field evolved resistance are unknown. In the present study, the resistance mechanism in field evolved resistance to maize producing Cry1Fa in Spodoptera frugiperda collected in fields from Puerto Rico was characterized. High levels of resistance to …

Effects Of Leaflet Orientation And Root Morphology On Physiological Traits And Yield In Soybeans., Richard Dewayne Johnson

Doctoral Dissertations

Drought is the most important abiotic stress adversely affecting soybean (Glycine max (L.) Merr.) yield. Leaflet orientation has been shown to reduce leaflet temperatures and transpiration while root morphology has been related to slower wilting phenotypes. The objective of this study was to investigate effects of leaflet orientation and rooting morphology on whole plant transpiration, yield, water use efficiency, and other physiological traits in soybeans using grafting techniques, population lines, near-isogenic lines, and restrained leaf canopy experiments. Experiments were conducted in Knoxville, TN with additional yield trial plots at Springfield, Spring Hill, and Milan, TN. Data were collected on …

Giant Ragweed (Ambrosia Trifida L.) Biology, Competition, And Control In Cotton (Gossypium Hirsutum L.), Kelly Anna Barnett

Doctoral Dissertations

The objectives of this research were to evaluate control options and investigate the biology and competitiveness of glyphosate-resistant (GR) giant ragweed in cotton. Our results determined that glufosinate followed by glufosinate, glufosinate plus pyrithiobac, and glufosinate plus fluometuron at 0.56 or 1.12 kg ai ha^-1 resulted in the highest level of visual control and the highest yield. However, glufosinate followed by glufosinate was the only treatment that resulted in the highest yield and > 90% control of GR giant ragweed.

The development of glufosinate-tolerant, 2,4-D tolerant, and dicamba-tolerant crops may provide growers with new opportunities for difficult-to-control weeds such as …

Efficacy Of Biopesticides For Organic Management Of Cucumber Beetles, Mary A. Rogers

Doctoral Dissertations

Organic growers are limited in crop protection techniques for cucumber beetle management. Spotted (Diabrotica undecimpunctata howardi) and striped (Acalymma vitatta) cucumber beetles and are significant pests of cucurbits in the U.S. Feeding results in aesthetic damage and reduction in marketable yields as well as transmission of bacterial wilt that can result in plant mortality. Biopesticides are products formulated from naturally occurring organisms such as fungi and bacteria that are pathogenic or toxic to insect pests. Advantages to these products are that they have low environmental risk, low risk to non-target organisms including mammals and beneficial insects, …