Poster Presentations (OARDC)

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This collection contains poster presentations made by faculty, staff and students. A group of posters of special note are those submitted by graduate students to the annual graduate student poster competition held in conjunction with the OARDC Annual Research Conference.


Recent Submissions

Now showing 1 - 20 of 194
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    Metabolic engineering for enhanced furfural tolerance during cellulosic butanol fermentation by glycerol-supplemented Clostridium beijerinckii
    (2016-06-17) Agu, Chidozie; Ujor, Victor C.; Ezeji, Thaddeus C.
    The inability of Clostridium beijerinckii to efficiently utilize glycerol, currently experiencing a market glut due to increased biodiesel production is a major impediment to adopting glycerol metabolism as a strategy for increasing NAD(P)H regeneration to mitigate lignocellulose-derived inhibitor ( e.g. furfural) toxicity, and improve butanol titer during fermentation of lignocellulosic biomass hydrolysates (LBH). Therefore, metabolic engineering was pursued to enhance glycerol utilization in C. beijerinckii to improve NAD(P)H regeneration and butanol production in furfural-replete LBH. Towards this goal, glycerol catabolic arsenal from the hyper-glycerol utilizing bacterium, Clostridium pasteurianum was cloned and overexpressed in C. beijerinckii. Glycerol dehydrogenase (gldh), the first enzyme in the glycerol catabolic pathway, catalyzes an NAD(P)H yielding reaction, dehydrogenation of glycerol to dihydroxyacetone (DHA) while the DHA kinase-catalyzed reaction yields a glycolytic intermediate (DHA phosphate). As a preliminary step, C. pasterianum gldh genes – dhaD1 and gldA1 were overexpressed as a fusion construct in an E. coli-Clostridium shuttle vector - pWUR460 under the control of constitutive thiolase promoter. The generated strain, C. beijerinckii-gldh was used to conduct batch acetone-butanol-ethanol (ABE) fermentation in a glucose-based medium supplemented with glycerol and 2, 3, 4, 5, or 6 g/L furfural. Fermentation profiles for all furfural concentrations show that C. beijerinckii-gldh accumulated significantly higher cell biomass (30 to 55%) when compared to the empty plasmid control. At high furfural concentrations (5 and 6 g/L), butanol production by C. beijerinckii_gldh were 10% and 46% higher, respectively, than the plasmid control. ABE concentration and productivity increased by 40.2% and 39.1% with 6 g/L furfural, and glycerol utilization increased by 44% to 70% for all furfural concentrations. Taken together, gldh overexpression in C. beijerinckii improved furfural tolerance and glycerol utilization in C. beijerinckii, thus, we infer that improved NAD(P)H regeneration stemming from glycerol catabolism supplies additional reducing power for efficient detoxification of furfural, which consequently promotes cell growth and butanol production.
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    The effect of soil cation balancing on soil properties and weed communities in an organic rotation
    (2015-05-13) Linder, Katie; Doohan, Douglas
    Many organic farmers in Ohio subscribe to soil balancing, or Base Cation Saturation Ratio (BCSR), to manage soil fertility, weeds and crops. BCSR calls for a balanced soil (~70% Ca, ~10% Mg, ~5%K). However, research has not substantiated this claim. An experiment was initiated in 2014 to evaluate the effect of BCSR on weed and crop communities, and soil properties in a 4-crop rotation. The experimental design is a randomized complete block, with 3 BCSR treatments, limestone, limestone with gypsum, GFF (a commercially-available blend from Green Field Farms Cooperative), plus a non-amended control. Soil was sampled in November 2013 and in September 2014, and analyzed for pH, base saturation and nutrient levels. Results of the 2013 samples were used for prescribing amendments applied in April 2014. Additional amendments were applied in fall of 2014. According to 2014 results, soil balance (defined above) was not achieved with the BCSR treatments. Soil pH, percent calcium and potassium were ideal in the gypsum and limestone plots, but magnesium was too high. In GFF plots, pH and percent calcium were too low, while magnesium was slightly elevated. Percent potassium was within the BCSR range, due to GFF’s 0-0-50 component. Aluminum was lower in gypsum and limestone plots, because calcium in these amendments replaces aluminum on soil exchange sites leading to displacement from the root zone. In 2015, we will adjust amendment rates to further balance the soil in treatment plots, and observe the impacts on crop growth and weed communities.
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    Response of grafted glyphosate-resistant and conventional soybean plants to glyphosate
    (2015-04-28) Chen, Yin; Doohan, Douglas
    Previous research established that grafting imparts herbicide tolerance from a glyphosate tolerant (RR) soybean rootstock to a conventional (CN) scion. However, no information is available regarding how soybean growth stage, genotype and environment affects the tolerance level expressed in the CN scion. Experiments were conducted in 2013 and 2014 to determine the effect of these variables. Three soybean growth stages (3, 6 and 10-leaf stage), graft combinations of 6 soybean genotypes (3 CN and 3 RR) and 2 temperature conditions were evaluated. Glyphosate rates used were 0.84 and 1.68 kg ae/ha. In every experiment all chimeras of CN/CN died and all RR/RR chimeras were injury free. The mean injury level of 3-leaf and 6-leaf stage chimeras was 72% while for the 10-leaf stage chimeras injury was 63% 24 days after treatment with 0.84 kg ae/ha glyphosate. When the glyphosate concentration was 1.68 kg ae/ha, the injury level of 3-leaf and 6-leaf stage chimeras was 83% and the 10-leaf stage chimera injury level was 74%. Genotype of the CN scion affected the expressed tolerance level of CN/RR chimeras; whereas, genotype of the RR rootstock had less effect. Among CN/RR genotype combinations, 352/9392 and 352/9328 were most tolerant while 5388/9392 was most susceptible. The temperature variation (day/night temperatures were 28/22°C or 24/18°C) showed no significant effect on tolerance of CN/RR, but the tolerance of 352/352 (CN/CN) to glyphosate increased when the temperature was lower.
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    Weed Control and Tolerance of Tomato (Solanum lycopersicum L.) to Fomesafen
    (2015-04-14) Mohseni-Moghadam, Mohsen; Doohan, Douglas
    Weed management in tomato (Solanum lycopersicum L.) continues to be a challenge for vegetable growers in Ohio. Field experiments were conducted at the North Central Agricultural Research Station in Fremont, OH in 2009 and 2010 to evaluate the tolerance of tomato to fomesafen and the efficacy of this herbicides on weed control. The crop was machine-transplanted in June 5, 2009 and June 3, 2010. The experimental design was a randomized complete block with 4 replications. Pre-transplant treatments were applied on June 4, 2009, and May 27, 2010 and included fomesafen at 280, 350, 420, 560, and 840 g ai ha-1. Crop injury and weed control were assessed visually using a linear scale in which 0 indicated no crop injury or weed control, and 100 indicated death of crop or total weed control. Plots were evaluated at 7, 14, 28, and 42 day after treatment. The crop was harvested on September 16, 2009 and September 30, 2010 and total yield per plot was determined. Minimal crop injury was observed 7 and 14 DAT in plots treated with fomesafen at 840 g ai ha-1 both years. However none of the treatments caused crop injury either years at 42 DAT. Fomesafen at the highest rate provided acceptable annual grass, common purslane, and redroot pigweed control 42 DAT. Fomesafen application did not reduce total tomato yield. Registration of fomesafen herbicide would provide tomato growers an opportunity to control weeds caused by late emergence or poor initial control following a burndown herbicide application in tomato.
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    Bioabatement to remove microbial inhibitors from Miscanthus giganteus hydrolysates for enhanced butanol fermentation
    (2015-04-27) Agu, Chidozie Victor; Ezeji, Thaddeus
    The recalcitrant nature of cheap lignocellulose warrants pretreatment process to disrupt the lignin matrix and expose the carbohydrate fraction to enzymatic saccharification. Generation of lignocellulose-derived microbial inhibitory compounds (LDMICs) during the pretreatment process undermines large-scale utilization of biomass for biofuel (e.g. butanol) production. LDMICs are derived from lignin (e.g. vanillin), cellulose (e.g. 5-hydroxymethylfurfural [HMF]), and hemicellulose (e.g. acetic acid) fractions of lignocellulose. These compounds impair butanol fermentation by disrupting the growth of butanol-producing Clostridium beijerinckii through diverse mechanisms including perturbation of redox and energy state of the cell, inhibition of glycolytic enzymes, and damage to cell membrane, nucleic acids and organelles. Although LDMICs can be removed from lignocellulosic biomass hydrolysates (LBH) by physicochemical methods, these methods increase the overall butanol production cost. Bioabatement, a cost-effective alternative, employs microorganisms that selectively metabolize LDMICs in the presence of fermentable sugars. In this study, we demonstrate the ability of the bacterium, Cupriavidus basilensis ATCC®BAA-699 to metabolize pure LDMICs and Miscanthus giganteus biomass hydrolysate (MH)-associated LDMICs. Notably, MH was generated by dilute-acid (2% H2SO4) pretreatment at 15% biomass solids loading in a reactor at 180˚C and 150 psi for 1 h. The hydrolysate was then detoxified by C. basilensis prior to enzymatic hydrolysis to release fermentable sugars. Acetone-butanol-ethanol (ABE) fermentation of C. basilensis-detoxified MH resulted in ~70% increase in ABE concentration when compared to the non-detoxified control. These results underscore the feasibility of biological removal of LDMICs from pre-enzyme hydrolyzed LBH prior to fermentation to butanol.
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    Long-legged fly (Diptera: Dolichopodidae) communities in Ohio agroecosystems and assessing their role as biological control agents in vegetable crops
    (2015-04-27) Kautz, Andrea; Gardiner, Mary
    Biological control is a vital ecosystem service provided by a diverse guild of predators in agroecosystems. Biodiversity is thought to be linked to ecosystem functioning through more efficient resource capture and niche partitioning. Understanding the factors that impact the diversity of these predators is therefore important to our understanding of how to enhance biocontrol services. Long-legged flies (Diptera: Dolichopodidae) are a particularly ubiquitous yet understudied group of insect predators that are common in all habitats in Ohio, including agricultural systems. Previous studies have shown that these flies are sensitive to environmental changes, at least in natural systems like grasslands and reed marshes. The goal of this study is to determine how field management and disturbance influences the community assemblage of Dolichopodidae found in agroecosystems. During the summer of 2013 and 2014, pan trapping was used to sample the dolichopodid community present in produce farms across northeast Ohio. Sweet corn, summer squash, and unmanaged old fields were sampled. Over 3,000 flies representing twelve dolichopodid genera were found. Analysis shows that overall dolichopodid abundance was actually higher in crop habitats than unmanaged habitats, and that the community within each habitat was different. Currently, a molecular gut content analysis is also being done to reveal the dietary composition of these flies. Identifying which factors are driving the diversity of this family of flies, as well as figuring out what they are eating, will help us understand how to maximize the biological control services being provided.
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    Improving Freezing Tolerance of Cold-Sensitive Grape Cultivars Using Abscisic Acid
    (2014-04-24) Li, Shouxin; Dami, Imed
    Grape and wine industries in colder regions such as Ohio have been expanding rapidly and demand for premium wine grapes has also increased. However, several popular cultivars are sensitive to freezing temperatures below -20°C. The goal of this study was to improve freezing tolerance of sensitive grape cultivars using abscisic acid (ABA). The objectives of this research are to: 1) evaluate the response of greenhouse- and field-grown wine grape cultivars to exogenous ABA, 2) characterize the changes of freezing tolerance, water content, and soluble sugars in bud tissues of greenhouse- and field-grown vines in response to exogenous ABA. In the field, we evaluated the effect of exogenous ABA on freezing tolerance and optimum timing of ABA application of Vitis vinifera ‘Pinot gris’. ‘Pinot gris’ grapevines were treated with 400mg/L ABA at different stages of development (veraison, post-veraison and post-harvest). The application of ABA did not affect yield components or fruit composition, but caused early leaf abscission, advanced bud dormancy, decreased bud water content, and eventually increased freezing tolerance. Greenhouse experiments showed that ABA caused desiccation of buds which was associated with increased freezing tolerance. Ultimately, the findings of this project are valuable to grape producers to provide another tool for freeze protection and to the scientific community for better understanding of the mechanisms of freezing tolerance.
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    Horizontal Gene Transfer and Gene Duplication of Plant Cell Wall Degrading Enzyme Genes in an Invasive Insect Pest
    (2014-04-30) Zhao, Chaoyang; Mittapalli, Omprakash
    Insects were long thought to lack endogenous genes encoding plant cell wall degrading enzymes (PCWDEs). However, this hypothesis has been challenged since symbiotic-independent PCWDE genes and enzymes were found in several insect species. As an economically-important wood-feeding beetle, how the invasive insect emerald ash borer (Agrilus planipennis) degrades plant cell walls and utilizes their contents is of high interest. We identified three glycoside hydrolase (GH) gene families and one polysaccharide lyase (PL) gene family within the A. planipennis genome, which putatively encode for α-L-arabinofuranosidases (GH43), endoglucanases (GH44), polygalacturonases (GH28) and Rhamnogalacturonases (PL4), respectively. Phylogenetic analysis showed that they exhibit close relationship with bacterial or fungal homologs, indicating that acquisition of these genes by the insect is through the horizontal gene transfer (HGT). Each family has multiple gene copies in the A. planipennis genome and they reside in the same clades, implying occurrence of the gene duplication events following HGT during evolution. To test the hypothesis that the HGT-associated gene duplication is adaptive, we selected one GH44 gene, two GH43 genes and one PL4 gene for quantitative RT-PCR analysis. The specific expression in the larval midgut and during larval stages of development, together with the presence of N-terminal signal peptides in the deduced protein sequences, suggest that these gene products are secreted into the larval midgut, facilitating digestion of the host plant cell walls.
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    Comparison of Parthenium argentatum and Hevea brasiliensis rubber: Effect of non-rubber constituents on rubber intrinsic properties
    (2014-04-29) Mohammad Ali Monadjemi, Shirin; Cornish, Katrina
    Natural rubber (NR) is an indispensable polymer used to manufacture industrial products and has many exceptional features that makes it as yet irreplaceable by synthetic rubber. Currently, almost all NR used in commerce comes from the hevea tree (Hevea brasiliensis). However, to meet the increasing demand for NR, guayule (Parthenium argentatum) has emerged on the market as a sustainable commercial source of high quality rubber. Guayule rubber (GR) has similarities to hevea rubber but also has unique properties. For example, it was found to be malleable at extremely cold temperatures. We aim to understand causes of this malleability to tap this potential for aerospace, cryogenic sealing, and other low temperature applications. Non-rubber constituents play an important role in NR intrinsic properties. We conducted research on GR malleability by comparing the effect of non rubber constituents, such as protein, lipid and resin. Firstly, a film casting method was developed to obtain rubber films with a uniform thickness. Secondly, the physical properties were tested by dynamic mechanical analysis (DMA). Acetone solubles (lipids and resin) were found to soften the rubber and behave as plasticizers. Furthermore, removal of the rubber particle membrane (proteins and lipids) was found to affect the tensile properties of the films.
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    A Tool to Assess Heating Efficiency of Direct-fired Heater with the Impact of Humidity Control
    (2014-04-28) Lee, Wee Fong; Ling, Peter P.
    Heating is one of the top two expenses of greenhouse operations in northern climates. Direct-fired heater (DFH) that has been promoted having high heating efficiency, 99.9%, compared to 80-94% of conventional indirect-fired heaters (IFH), could be an energy efficient choice. However, the high efficiency claim does not consider energy lost through air intake during combustion process. Fresh air intake is important for clean combustion and extra dehumidification for the water vapor generated from the combustion process to maintain a healthy environment for plant growth. The actual heating efficiency of a DFH is affected by amount of fresh air intake where higher air intake rate causes lower heating efficiency. A decision support tool (the tool, thereafter) was developed to determine the minimum air intake needs for the combustion and water removal, thus, the highest net heating efficiency of a DFH can achieve. In a case study, the tool predicted that a DFH had a net heating efficiency of 86%. The prediction was verified with field experiments to compare heating performance of the DFH to a popular IFH. The results showed varied DFH heating efficiency that was affected by the heater operation strategy to regulate fresh air intake rate. A higher heating efficiency was achieved with a fresh air intake rate determined by the tool. The DFH consumed 8.8% less fuel than that of the IFH. The field tested DFH heating efficiency was 87% which was in close agreement with the prediction of the tool.
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    Transcriptomic evidence for dramatic functional transition of the Malpighian Tubules after a blood meal in the Asian tiger mosquito Aedes albopictus
    (2014-04-28) Esquivel, Carlos; Piermarini, Peter M
    Vector-borne diseases transmitted by mosquitoes are important for global health, because cause hundreds of thousands of deaths and sickening hundreds of millions people each year. The Asian tiger mosquito (Aedes albopictus), is enhancing this risk in the world and the United States. Ae. albopictus is vector of diseases such as West Nile fever, dengue fever, chikungunya fever, and Eastern Equine Encephalitis. To date, this research has used single-end RNA-Seq to demonstrate that a blood meal affects the expression of more than 1800 non-redundant transcripts and 15 metabolic pathways in Malpighian tubules of the Asian tiger mosquito, in a manner that suggests a potential functional transition in the epithelium from one dedicated to salt and water excretion to one dedicated to the metabolism and excretion of metabolites derived from a blood meal.
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    Predicting food production potential of urban vacant lots through soil quality
    (2011) Cheng, Zhiqiang; Grewal, Parwinder
    Post-industrial cities such as Cleveland have accumulated substantial number of vacant lots due to home foreclosures and urban sprawl over the past two decades. Interest in this land has escalated recently due to increased demand for food security in disadvantaged urban neighborhoods. We measured soil physical, chemical, and biological parameters in vacant lots in the Hough neighborhood in Cleveland to assess their suitability for food production. Each lot was divided into three approximately equal sections and nine soil cores were collected from each section. The results revealed huge spatial variability in soil properties within vacant lots. Soil pH ranged from 6.24-7.46 and moisture from 1.5-20.5%. Soil clay content ranged from 4-33%, sand 40-92%, and silt 0-50%. Soil NH4-N ranged from 1.7-21.0 ppm, NO3-N from 2.3-35.3 ppm, microbial biomass from 40.2-245.7 ppm (N), soil organic matter from 2.0-7.0%, and soil active carbon from 413.3-694.8 mg/kg. Thirty-four nematode genera were identified, and nematode abundance ranged from 34 to 988 per sample. Soil active carbon, a rapid soil quality indicator, significantly correlated with other measures of ecosystem condition including NH4-N, microbial biomass, soil organic matter, nematode abundance, maturity index, and combined maturity index. Principle Component Analysis revealed that vacant lots had less structured soil food webs than turfgrass lawns, but not from community gardens and vegetable farms. There were also no differences in nematode abundance, genus diversity, and enrichment index among vacant lots, turfgrass lawns, community gardens and vegetable farms. Our results indicate high potential for food production in urban vacant lots.
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    Cooperative endurance: A remarkable strategy adopted by symbiotic bacteria to persist in their nematode vector
    (2011-05-06) An, Ruisheng; Grewal, Parwinder
    Symbioses between microbes and animals are ubiquitous, yet little is known about the intricate mechanisms maintaining such associations. In an emerging animal-microbe symbiosis model system represented by the partnership between insect-pathogenic bacteria Photorhabdus temperata and insect-parasitic nematodes Heterorhabditis bacteriophora, we investigated molecular mechanisms adopted by the bacteria to persist in the enduring nematode vector in search of their insect host. Using selective capture of transcribed sequences approach, 50 transcripts were identified to be up-regulated and 56 were down-regulated by the bacteria during persistence in the nematode compared with growth in culture medium. Real-time PCR analysis of 14 representative transcripts displayed 6-12 fold change in expression, reflecting a significant shift in bacterial gene expression in the nematode. The identified transcripts included but not limited to genes involved in proton transport, metabolic pathways, biofilm formation and cell motility, suggesting that the bacteria undergo major transcriptional reshaping in the nematode vector. Besides general starvation mechanisms, the bacteria induce cellular acidification to slow down growth, switch to pentose phosphate pathway to overcome oxidative stress and nutrition limitation, and shed motility but develop biofilm to persist in the nematode intestine until being released into the insect hemolymph. Our mutation data further confirm that such transcriptional reshaping is critical for bacteria to persist in the nematode infective juvenile. These findings demonstrate how the symbiotic bacteria reduce their nutritional dependence on the enduring nematode partner to ensure successful transmission of the couple to the next insect host.
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    Cooling Capacity Assessment of Semi-closed Greenhouses
    (2011-05-02) Lee, Wee Fong; Ling, Peter P.
    Energy and labor are the two largest expenditures of greenhouse operations. High energy cost and large CO2 footprint associated with greenhouse heating have motivated research activities in the areas of energy conservation and alternative energy. Dutch researchers have demonstrated energy saving potential of closed greenhouse operation in the Netherlands. This study hypothesized that semi-closed operation was better suited for Ohio and other US northern climate regions. A decision support tool has been developed to assess energy recovery potential and other benefits of semi-closed operations. The results showed that a greenhouse can be closed 90% of the time using only 50% of the maximum cooling capacity required to keep a greenhouse closed 100% of the time. Also, heat recovered from cooling operations of a closed greenhouse in Ohio can contribute 23-98% of total annual heating needs. This study also found large disagreement when using a commonly used tool for heat loss calculation. The tool performed poorly with a 30% error under nighttime clear sky conditions. The evaluation suggested that accurate estimation of net solar radiation transmittance is important, e.g. a 5% change of the transmittance caused a 9% prediction performance shift. In addition to the originally designed functions, the decision support tool is extended to predict the performance of external shade curtains for cooling purposes. The development of this tool has established a solid foundation for the evaluation of greenhouse energy management strategies, including feasibility studies of alternative energy sources, and of sizing of greenhouse heating and cooling equipments.
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    Quantification of apo-lycopenals in food products and human blood plasma
    (2009-03-31T17:59:20Z) Kopec, Rachel E.; Schwartz, Steven J.
    Consumption of tomato and tomato products is correlated with a reduced incidence of a number of diseases. Research has suggested that lycopene, the most predominant carotenoid in tomatoes, may be responsible for this effect. However, researchers have also suggested that lycopene may be metabolized in mammals by eccentric cleavage to biologically active aldehydes, in an analogous fashion to cleavage of ß-carotene, catalyzed by ß-carotene oxygenase. Since apo-6’- and apo-8’-lycopenal have been reported earlier in raw tomato, we hypothesized that several other apo-lycopenals may be present in raw and processed foods, as well as blood plasma. Apo-lycopenal standards were prepared by in vitro oxidation of lycopene, and an HPLC-MSMS method using atmospheric pressure chemical ionization in negative mode was developed to separate and detect the apo-6’-, 8’-, 10’-, 12’-, 14’-, and 15’-lycopenal products formed in the reaction. Hexane/acetone extracts of raw tomato, grapefruit, watermelon, and processed tomato products were analyzed, as well as blood plasma of individuals who had consumed tomato juice for 8 weeks. Apo-6’-, 8’-, 10’-, 12’-, and 14’-lycopenals were detected and quantified in all food products tested, as well as blood plasma. The sum of apo-lycopenals was 6.5µg/100g roma tomato, 73.4 µg/100g tomato paste, and 1.88nmol/L of blood plasma. We conclude that several apo-lycopenals, in addition to apo-6’- and 8’-, are present in lycopene containing foods. In addition, the presence of apo-lycopenals in plasma may partly derive from the absorption of apo-lycopenals directly from food.
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    Life history of Bemisia tabaci biotype B on poinsettia cultivars: do they prefer light green leaf cultivars?
    (2009-03-31T17:59:08Z) Medina-Ortega, Karla J.; Cañas, Luis A.
    The silverleaf whitefly (SLWF), Bemisia tabaci biotype B, is one of the most prevalent insect pests found attacking poinsettias. Ohio is the fifth largest producer of poinsettias in the nation with poinsettias ranking as the nation’s top selling potted ornamental. Little is known about the physical and chemical traits present in poinsettia cultivars that affect whitefly life history; however, my previous work has shown poinsettia cultivars differ in susceptibility to the silverleaf whitefly. Over all, dark colored leaves significantly have less whitefly survival and adults settling compared to light colored leaf poinsettias. It is hypothesized that visual cues play an important role in attracting whiteflies populations in poinsettias. To further investigate plant factors involved in susceptibility to whiteflies a visual cues choice experiment was conducted with one dark green leaf and one light green leaf cultivar, were adult settling and oviposition were measured. It is also hypothesized that amino acid profile and morphological traits such as trichome density, specific leaf area, and chlorophyll content are factors affecting host choice by the SLWF. Our study shows adult settling and oviposition preference by the SLWF is significantly affected by the presence of visual cues. A strong preference is observed for light green leaf cultivars. Light green leaf poinsettias differed in the amino acid profile compared to dark green leaf plants. In addition, specific leaf area and chlorophyll content differs between the cultivars. Trichome density did not differ among cultivars. Visual, chemical and physical characteristics play a role in whitefly host selection.
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    Profiling Nutritionally Important Carotenoids from Genetically-Diverse Tomatoes by IR Spectroscopy
    (2009-03-31T17:58:58Z) Rubio-Diaz, Daniel E.; Rodriguez-Saona, Luis E.
    The objective of this research was to develop a protocol for profiling tomato carotenoids based on their specific vibrational spectroscopic signatures. Twenty four tomato varieties that included eight groups of genetically manipulated carotenoid varieties (high trans-lycopene, poly-cis-lycopene, β-carotene, poly-cis-β-carotene, δ-carotene, tangerine virescent, alcabaca-tangerine, and a low-carotenoid control sample) were grown and harvested in a replicated trial. Hexane was used to extract the lipid fraction from samples, and the extract was directly applied onto an ATR ZnSe crystal plate for spectra acquisition and injected in a reverse phase HPLC system for carotenoid separation. SIMCA classified tomatoes based on unique infrared spectral signatures. Models exhibited tight and well-separated clusters (interclass distances >3.0) that correlated well with the information obtained by HPLC, and demonstrated the capability to classify tomatoes based on variety and carotenoid profile. Classification of lipid fractions was primarily based on the presence of trans double bonds and their cis and trans conjugations. Major discriminating bands were 957cm-1 and 964cm-1 associated with bending trans HC=CH out-of-plane deformation vibrations of carotenoids. ATR-IR and multivariate analysis provided a simple, rapid and high-throughput tool for the identification of dietary carotenoids. This technique will facilitate the effective selection of tomato varieties with specific pigment content, improving the screening process for carotenoid-rich products.
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    High-throughput differentiation of Streptococcus thermophilus and Lactobacillus spp. strains used in Swiss cheese production by infrared microspectroscopy
    (2009-03-31T17:58:45Z) Prabhakar, Veena; Rodriguez-Saona, Luis E.
    Swiss cheese production in US was 310 million lbs (3.2% of total cheese production) in 2008. Ohio is the leading Swiss cheese producer in the US, supplying over 42% of the total US production. Strain variations of starter cultures have an impact on final quality and hence the price of Swiss cheese. A rapid and cost-effective method for identification and differentiation of starter cultures at strain level could help maintain uniform quality of Swiss cheese. The study was focused on developing a high-throughput technique to identify and differentiate Streptococcus thermophilus and Lactobacillus spp. strains involved in Swiss cheese production using the combination of hydrophobic grid membrane (HGM) filters and Fourier transform infrared (FTIR) microspectroscopy. Strains of S. thermophilus (14) and Lactobacillus spp. (15) were analyzed. Aliquots (2 µL) of each strain were transferred onto a grid of the HGM filter vacuum dried in a desiccator and analyzed using FTIR microspectroscopy. The procedure was repeated on six different days to account for growth variability. The spectra were analyzed by soft independent modeling of class analogy. The pattern recognition analysis showed tight clustering at the strain level for models developed for S. thermophilus and Lactobacillus spp. The models showed unique patterns in the spectral region from 1150 to 1000 cm-1 for the major discrimination in the S. thermophilus and Lactobacillus spp. that can be attributed to differences C-O stretching of polysaccharides. This method could be an effective tool to identify and monitor activity of dairy cultures.
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    Retention and bioaccessibility of β-carotene in cassava (Manihot esculanta, Crantz) are affected by style of cooking
    (2009-03-31T17:58:35Z) Thakkar, Sagar K.; Failla, Mark L.
    We previously demonstrated that the bioaccessibility of β-carotene (BC) in boiled cassava from various cultivars is highly correlated with BC content. However, cassava is also prepared by fermentation followed by either boiling (fufu) or roasting (gari). The potential impact of such processing on retention and bioaccessibility of BC was investigated. We first compared retention of BC in boiled cassava, gari, and fufu each prepared from the roots of three different cultivars. BC content in unprocessed cultivars was 6-8 µg/g wet weight and cis isomers accounting for approximately one-third of total BC. Apparent retention of BC was approximately 90% for boiled cassava and fufu. In contrast, roasting fermented cassava at 195°C for 20 min to prepare gari decreased BC content by 90%. Retention was increased to 63% when roasting temperature was reduced to 165°C for 10 min. Processing also was associated with a decline in all trans ¬BC and concomitant increase in 13-cis BC. The efficiency of micellarization of all trans and cis isomers of BC during simulated digestion was 25-30% for both boiled cassava and gari and independent of cultivar, but only 12-15% for fufu. These differences in retention and bioaccessibility of BC from cassava processed in traditional styles suggest that gari and fufu likely provide fewer retinol activity equivalents than an equivalent caloric intake of boiled cassava.
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    The Effect of Acylation on the Inhibition of HT-29 Cancer Cell Proliferation by Anthocyanin Pigments
    (2009-03-31T17:58:27Z) Willig, Jennifer A.; Giusti, M. Monica
    Anthocyanins are the red, purple, and blue pigments found in many fruits and vegetables. Research shows that anthocyanin-rich extracts can slow the growth of colon cancer cells. Acylated anthocyanins exhibit increased stability in food matrices as compared to non-acylated anthocyanins, and can be used as food colorants. With the addition of acylation comes added protection from environmental conditions, but acylation may affect anthocyanins bioavailability and bioactivity. The objective of this study was to evaluate the role of acylation on anthocyanin chemoprotective properties. Acylated cyanidin derivatives were extracted from red onion, purple corn (anthocyanins acylated with aliphatic acids), red cabbage and black carrot (anthocyanins acylated with cinnamic acids). Non-acylated anthocyanins were obtained by saponification of these materials. Chemoprotective properties of the extracts were tested on human colon adenocarcinoma cells (HT29). Growth inhibition was measured using the sulfurhodamine B assay. Saponification increased or maintained anthocyanin chemoprotective abilities. Results suggest that acylation and glycosylation patterns impact HT-29 cell inhibition. For example, at a dose of 100µg/ml, acylated and non-acylated red onion anthocyanins showed 120.3 and 92.5 percent inhibition respectively; where acylated and non-acylated red cabbage anthocyanins showed 20.4 and 24.7 percent growth inhibition respectively. Both the acylated and the non-acylated anthocyanin extracts displayed inhibition properties when added to human adenocarcinoma cells (HT29). However, due to increased stability, acylated anthocyanin extracts may impart a higher level of chemoprevention than non-acylated anthocyanin extracts and also may be more widely used by the food industry in the production of functional foods.