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Item A frontotemporal dementia and motor neuron disease mouse model of tdp-43 proteinopathyHarmon, AshleyMotor neuron disease (MND), of which amyotrophic lateral sclerosis (ALS) is one example is a neurological disorder that involves the progressive loss of motor neurons. The death of these motor neurons leads to a loss of voluntary muscle control that can affect speaking, walking, breathing, and swallowing leading eventually to death. There is currently no cure for ALS therefore understanding mechanisms associated with the progression of this disease is crucial to developing a treatment. Transactive response DNA binding protein of 43kda (TDP-43) functions as a heterogeneous nuclear ribonucleoprotein (hnRNP) and is the major pathological protein in frontotemporal dementia (FTD, 50%) and sporadic ALS (95%). Mutations in TDP-43 account for ~5% of familial ALS cases. In a subset of cases with TDP-43 proteinopathy, patients clinically display both frontotemporal temporal dementia and motor deficits (FTD-MND). We have characterized an age-dependent decrease in motor function associated with pathological changes in mice selectively driving TDP-43 expression in the spinal cord and brain using a neuronal-specific (Prion) driver. Expression of a nuclear localization defective (NLS) TDP-43 mutant in spinal cord and brain showed severe motor deficit and significant changes in anxiety in 16-18 month old mice. Although there was a relatively late onset of symptoms compared to the human disease, that may be related to the low level of exogenous TDP-43 expression, these models may provide a better understanding of TDP-43 proteinopathies leading to the development of therapeutics to target these devastating diseases.Item Adult atlantic sturgeon (acipenser oxyrinchus oxyrinchus) habitat use and run-size in the Hudson River Hyde Park Reach, NYComer, Amy MarieSturgeons (Acipenseridae) including the Atlantic Sturgeon (Acipenser oxyrinchus oxyrinchus) are among the most threatened family of vertebrates. In the United States, Atlantic Sturgeon were listed under the Endangered Species Act in 2012. The listing delineated five Distinct Population Segments (DPS), four of which were classified as endangered (New York Bight (NYB), Chesapeake Bay, Carolina, and South Atlantic), while the Gulf of Maine was listed as threatened. Overall, Atlantic Sturgeon populations are significantly reduced from historic levels as a result of overfishing, habitat loss, and pollution. In the Hudson River, Atlantic Sturgeons population size has been affected heavily due to overfishing in the late 1800’s. For recovery of the species, it’s important to understand their habitat requirements. The first objective of my thesis was to assess adult Atlantic Sturgeon habitat use during their annual spawning migration while on purported spawning grounds. During 2013 and 2014, I surveyed the Hyde Park Reach of the Hudson River, NY using side-scan sonar which is a non-invasive sampling option. In this region, Atlantic Sturgeon selected for sand and muddy sands with sands substrates. Within the study site, hotspots of Atlantic Sturgeon were delineated in the middle of the reach just south of Esopus Island, and in the southeastern portion of the reach near Rogers Point. These likely spawners used multiple sediment types while in the riverine environment. The results of this study suggest Atlantic Sturgeon use the Hyde Park Reach as a possible spawning and staging site. These results also suggest that sediment type is not the only variable that is driving Atlantic Sturgeon presence. My second objective was to estimate the 2014 likely spawners run size of Atlantic Sturgeon using Swept-Area and N-mixture modeling. Estimated run-size abundances in the Hyde Park Reach using swept-area were 113 – 188 Atlantic Sturgeon (95% CI’s 74-275) for four-three consecutive surveys between 06/11/14 – 07/02/14 while N-mixture estimates were 171 – 306 Atlantic sturgeon (95% CI’s 75 – 560). It is important to note that these estimates do not account for individuals occurring in the other spawning sites in the Hudson River. Comparing the two models, the N-mixture model produced estimates at approximately 1 – 2.3 times larger than swept-area estimates per time-period, likely due to the large variation in daily count data. In the case of a highly mobile species such as the Atlantic Sturgeon, it may be prudent to increase site sizes to include average movement of sturgeon, which would help to meet the assumptions of N-mixture modeling, and reduce variation in model estimates. Through my research efforts, I have been able to successfully sample Atlantic Sturgeon while on proposed spawning grounds with a non-invasive technology, which allowed for fine-scale habitat and behavior information during an important life stage that is currently not well understood. Gaining insights into the Hyde Park Reach as a possible spawning and staging location, will help to serve as important with future management efforts. Furthermore, understanding that sediment type may not be the only important factor while adult Atlantic Sturgeon are in the riverine environment and that habitat features near spawning grounds may want to be considered when developing management actions and the critical habitat designations in the riverine environment. Data from this thesis further underscores the need to identify and protect critical habitats thereby fostering conservation and recovery of this imperiled species. Finally, through this research I was also able to integrate side-scan sonar and acoustic telemetry as an effective approach for estimating run-size abundance of in the Hyde Park Reach of the Hudson River. The approach presented here appears to be a viable option and can be fitted for Atlantic Sturgeon or other large species in other river systems, which could aid in the restoration of this endangered species.Item An Evaluation of a Northern Bobwhite (Colinus virginianus) Parent-reared Release in South CarolinaHaley, RyanNorthern bobwhites (Colinus virginianus) have experienced large, range-wide declines mainly attributed to the loss of early-successional habitat. Bobwhite population recovery is predicated on sound habitat management. Even when adequate habitat exists, low bobwhite densities and limited dispersal capabilities may limit population recovery. Restocking techniques, including release of pen-reared birds, wild bobwhite translocation, and the use of wild-strained, parent-reared captive-raised bobwhites have been explored as surrogates to natural recolonization. In this study, I evaluated survival and reproduction of parent-reared bobwhites, compared to resident bobwhites, on a private property in South Carolina from April 2009-April 2013. I used a sequential modeling approach to evaluate adult survival and nest survival using Program MARK. Bobwhite survival was best explained by temporal (annual and weekly) effects and group (parent-reared vs. resident) effects. Weekly bobwhite survival for both parent-reared and resident bobwhites was too low to produce a stable population. Parent-reared bobwhite survival was lower than resident bobwhites during the first 3 weeks post-release but similar during later weeks. Parent-reared bobwhites released in August had higher survival (S = 0.884, 95% CI = 0.862, 0.903) than birds released in early fall (S = 0.707, 95% CI = 0.621, 0.782). Nest survival and other reproductive parameters for parent-reared and resident bobwhite were similar. The viability of the parent-reared release system as a restocking technique is limited as currently constructed and future modification is needed if it is to produce a viable bobwhite populationItem An examination of recreational angling for sharks in Delaware watersJohnson, SymoneRecreational angling targeting prohibited shark species (e.g. Sand Tiger (Carcharias taurus) and Sandbar (Carcharhinus plumbeus) Sharks) has increased in Delaware, raising concerns about the population status of these species. In an attempt to help address these concerns, my thesis had two objectives: to better understand recreational anglers’ perceptions of and interactions with prohibited sharks; and to explore gear modifications that result in minimizing harm to shark species caught during recreational angling. To achieve my first objective, I developed an angler survey with the goals of: 1) improving our understanding of threats to sharks, 2) identifying potential solutions to threats of shark conservation, and 3) improving fisheries management of sharks through reduced injury or mortality. The survey highlighted the need for improved accuracy in species identification and compliancy with best angling practices and/or regulations as threats to shark conservation. My findings suggest that resource managers may modify their approaches to reduce injury or mortality of sharks through increased angler education and training, K-12 education, social media campaigns, and increased enforcement. Building upon this, I examined the efficacy of experimental (blocker) longline gangions compared to control gangions for reducing damage to individual Sand Tiger and Sandbar Sharks during capture events. Over a three year period (2012-2014) comprising of 153 longline sets, I landed 493 Sand Tiger and 240 Sandbar Sharks. Overall catch rates of Sand Tigers (p = 0.024) and Sandbar Sharks (p = 0.013) were reduced on the experimental gangions. Gear type had a marked impact on hooking location (p = 0.003) for Sand Tigers as the overwhelming majority (96.3%) of gut hooked Sand Tiger individuals were encountered on control gangions. The use of blocker gangions shows much promise in minimizing risk of injury for Sand Tigers captured during longline surveys. In the case of Sandbar Sharks, there were no incidents of gut hooking in the entire study suggesting that the risk of injury from gut hooking is minimal for the species. The marked decline in gut hooking rates with Sand Tigers noted with the use of the experimental gangions underscores its potential use as a tool to reduce injury risk and to improve post-release survival prospects. It is well understood that a healthy marine environment provides direct and indirect economic awards and healthy shark populations are a key point in these environments. I hope my efforts to provide insights on angling preferences and practices in Delaware, as well as a potential tool for use in the angling community, will help foster increased recovery prospects for these important species.Item Astrocytic expression of TDP-43 results in non-cell autonomous changesCarter, Deidre LynnTAR DNA binding protein 43 (TDP-43) is a heterogeneous nuclear ribonucleoprotein that regulates gene expression, RNA stability, and is involved in shuttling back and forth from the nucleus to the cytoplasm. TDP-43 is predominantly localized to the nucleus. Glial Fibrillary Acidic Protein (GFAP) is a major astrocyte marker whose expression increases when astrocytes are activated. We have developed a mouse model that selectively and conditionally expresses a defective nuclear localization signal of TDP-43 (NLS) under control of the astrocytic GFAP promoter to investigate pathological outcomes and non-cell autonomous effects of TDP-43 mis-expression. We hypothesize that GFAP/TDP-43NLS mice will show non-cell autonomous changes in neurons caused by expression of TDP-43NLS in astrocytes. In order to characterize this model of astrocyte expression, an exon array was used to examine global changes in RNA expression/splicing in the spinal cord of two-month old mice. In addition, immunohistochemistry in both two-month old and six-month-old mice reveal age-dependent changes in myelin basic protein. At two months of age GFAP/TDP-43NLS mice display functional changes in memory, which may be associated with the changes in myelination observed. Primary cortical neuron/astrocyte co-cultures expressing TDP-43NLS exclusively in astrocytes show a significant decrease in neurons (as shown by III-tubulin immunoreactivity) compared with littermate controls. These data suggest that astrocytic expression of TDP-43NLS alters neuronal function both in vitro and in vivo. This study may provide insight and a better understanding of how astrocytic accumulation/aggregation of TDP-43 contributes to neurodegeneration.Item Atlantic Sturgeon (Acipenser oxyrinchus oxyrinchus) Behavioral Responses to Vessel Traffic and Habitat Use in the Delaware River, USADiJohnson, AlexanderThe Atlantic Sturgeon (Acipenser oxyrinchus oxyrinchus), a large, long-lived, anadromous species, experienced rapid population declines in later part of the 19th century due to overfishing and habitat loss. The Atlantic Sturgeon was listed under the U.S. Endangered Species Act (ESA) in 2012. Vessel strikes and habitat destruction, along with water quality degradation and bycatch mortality, were listed as major threats to the recovery of the species in the ESA determination. My study was conducted to further understand behavioral responses of Atlantic Sturgeon to vessel traffic and to indicate habitat preferences within an area of presumed spawning and foraging within the Delaware River. During the spring and summer of 2013 and 2015, I used a VEMCO Positioning System to monitor fine-scale movements of telemetered adult and subadult Atlantic Sturgeon. I used sturgeon spatiotemporal positions together with, commercial vessel traffic tracking data to observe possible differences between movement types, defined by using trajectory analyses for my first objective. Telemetered adult Atlantic Sturgeon exhibited several behavior types although I found no evidence that these behaviors were influenced by commercial shipping. For my second objective, I modeled habitat use of Atlantic Sturgeon in relation to Delaware River sediment types to observe whether sturgeons selected different proportions of the sediment than available. While subadults were shown to avoid muddy and sandy sediment, adults preferred course grain sediments (e.g., gravel) and avoided soft sediments (mud and sand). These results support the findings of previous studies which proposed that the study area was likely used for spawning/staging by adults during the early summer months. My findings suggest that Atlantic Sturgeon exhibit no behavioral responses to vessel presence and that individuals select areas of occupancy based on available sediments. This has direct implications in species conservation due to the continued alteration of sediments to support an increasing vessel traffic through maintenance dredging and channel deepening. If vessel avoidance is not occurring, managers must consider alternative ways of avoiding vessel strikes (e.g., seasonal restrictions such as limits to speed, draft depth, and passing zones) while also considering issues of continued sediment (i.e., habitat) alteration in critical areas of the river.Item Bat Activity on Golf Courses in DelawareWallrichs, MeganDue to landscape modifications and chemical use, golf courses have earned a negative reputation among some environmental groups, but their park-like landscapes may offer habitat for some wildlife species, especially over other land use types. In this study, I monitored bat activity using ultrasonic acoustic detectors in different small-scale habitats found on golf courses on the Delmarva Peninsula. My objective was to evaluate if and how bats are using course landscapes. I found differences in overall activity levels at the habitat level but not on different golf courses. Areas with closed canopy and open understory that were managed had significantly higher activity than other four habitats that reflected more natural habitats (open grass, dense canopy forest fragment, and open canopy forest fragment). The open understory managed areas also had significantly higher foraging activity than the other four habitats. Six of the eight bat species thought to occur on the Delmarva Peninsula were recorded, but Eptesicus fuscus and Lasiurus borealis dominated bat activity across all golf courses and habitats and had highest activity in open understory managed habitat. These findings indicate that bats are using golf courses on the Peninsula regularly as flyways and foraging grounds, and even substantially disturbed areas are used extensively. This study adds to the growing body of literature that positive partnerships can be created between wildlife and golf courses.Item Behavioral consequences of point mutations in the vesicular acetylcholine transporterWhite, DanielThe neurotransmitter acetylcholine (ACh) is involved in critical organismal functions as locomotion, learning and memory. Therefore, alterations in this neurotransmitter system is a key underlying factor in movement and cognitive deficits. The vesicular acetylcholine transporter (VAChT) mediates the packaging of ACh into synaptic vesicles for exocytotic release. Mutations in this protein ultimately diminish locomotion whereas complete loss of function of VAChT is fatal. The direct role of altered acetylcholine release and its association with impairment or enhancement of cognitive functions is still not fully understood. We hypothesize that point mutations in VAChT causes age-related deficits in cholinergic-mediated behaviors such as locomotion, learning and memory. Using Drosophila melanogaster as a model system, we have generated several mutations within VAChT and observed its effect on survivability, longevity and locomotive behavior. Here we report that VAChT point mutants causes defects in locomotion ability and an allele dependent deficit in lifespan. These results demonstrate that cholinergic release is important for the regulation of behavioral performance in Drosophila. In future studies, we will test methodologies to effectively rescue these deficits with implications for intervention strategies to treat cholinergic deprived disorders such as Alzheimer’s disease. Future studies will turn to investigating the effects of VAChT overexpression to determine whether the deficits seen in the Vacht mutants can be decreased or reversed.Item Characterization of strawberry (fragaria ananassa) by genotyping and phenotypingBiswas, AnjuStrawberry is an important fruit crop for its nutritional value and is known to have a higher amount of antioxidants. Consuming strawberries can increase dietary antioxidants. Antioxidants in strawberry can act against cardiovascular diseases, cancer, and other health issues. Recently, use of molecular markers is becoming popular in strawberry breeding programs as well as in genotyping of existing varieties. Genotyping is the process of determining genetic differences among individual plants and can be readily applied to identify genetic diversity among the germplasm. Simple sequence repeat (SSR) markers present in every living organism. Majority of the SSR markers are used for genotyping includes cultivar identification, genetic diversity analysis, taxonomic analysis, marker-assisted breeding, and cloning. It is easier to identify a trait of interest in any genotype if known SSR markers are available. Cultivated strawberries have a wide range of SSR markers available which permits to detect polymorphism of closely related genotypes as the genome of strawberries has been sequenced. In this study, we genotyped thirty-three strawberry accessions utilizing thirty-five SSR markers and phenotyped by observing leaf total antioxidant (TA) content, leaf shape, leaf trichome density and petiole size. DNA extraction, PCR, and SSR analysis were done for genotyping. We identified two distinct genetic groups from those genotypes, one group is alpine (wild or woody) type strawberry and another group is the cultivated type. In this study, we identified 120 alleles with an average of 3.43 alleles per locus. The genetic polymorphism ranged from 0.1461 for the marker ARSFL_9 to 1.6635 for the marker FG1a/b. All thirty-three accessions were grouped into clusters based on the genetic diversity analysis and found that grouping them into three clusters was provided the maximum genetic diversity. The cluster three contained more diverse genotypes among those. Leaf total antioxidant content was measured in Trolox equivalent amounts by colorimetric assays. The highest antioxidant containing genotypes were Earliglow, Wendy, Elan hybrid, Clancy, and Record. Spectrophotometer and high-resolution camera were used for phenotyping. We classified all genotypes into five groups according to the leaf shape and three groups according to the leaf trichome density and leaf petiole size. From the association, the two genotypes named Clancy and Elan hybrid contained more total antioxidant content with high trichome density. Strawberry breeding programs can utilize information from this research during cultivar development and authentication of genotypes.Item Comparative RNA-Seq Analysis of Phenotypically Different Sweetpotatoes (Ipomoea batatas [L.] Lam)Fiedler, Elizabeth Ann MarieSweetpotato is arguably one of Earth’s top ten most important crops. It is relatively low maintenance, packed with essential vitamins and nutrients, and in addition to serving as an effective food crop, it has been suggested for use as a material for synthesizing plastics and as a replacement for corn as a source for bioethanol production. Sweetpotatoes are difficult to bring to seed, so most sweetpotato plants are grown from slips, which are cuttings from sweetpotato vines. This makes it very easy for sweetpotato viruses to spread from generation to generation. Currently, virus disease complexes, which are infections of two or more viruses with a synergistic interaction, pose the biggest threat to sweetpotato yields. It is therefore crucial to have a better understanding of different sweetpotato genotypes. Sweetpotato genotypes tend to be very similar, since crossing and outbreeding strategies are all but impossible to carry out on sweetpotatoes, as different genotypes tend to be very similar. Transcriptome profiling could prove to be an extremely useful method for understanding the causes of phenotypic differences in genotypes. This project details the construction of the transcriptome profiles of three phenotypically different genotypes. Illumina sequencing was carried out on the 2500HiSeq platform and the resulting reads were aligned to the sweetpotato genome constructed by the Max Planck Institute. Bioinformatics software was used to carry out alignment and analysis. The analysis techniques were used to calculate and normalize gene expression, make fold change comparisons, convert this data to log 2-fold change, determine which genes had the greatest expression differences, group these genes into functional groups, and perform other analyses.Item Development of A High-Power Pulsed Laser via Sum-Frequency Generation for Sodium Lidar ApplicationsEbongue, Christiane A.We present the development of a nanosecond pulsed laser system resonating at sodium wavelength (589 nm) by means of sum frequency generation (SFG) with Nd:YAG lasers at 1064 nm and 1319 nm. This research is aimed to perform lidar measurements at mesospheric altitude, using sodium atoms as the tracer. These measurements include the determination of the sodium density, temperature and radial velocity. Two high power lasers at 1064 nm and 1319 nm are constructed using commercially available Nd:YAG gain modules as building blocks. The radiations emitted by the diode pumped Nd:YAG gain modules are picked up by two respective hemispherical optical cavities designed with high reflective mirrors at 1064 nm and 1319 nm, to produce stimulated emission at each wavelength. The 589 nm laser radiation is obtained by the sum frequency generation (SFG) of the two Nd:YAG pump laser outputs in a nonlinear crystal. Perfect mode matching, beam overlap, as well as temporal overlap of Q-switched pump laser pulses are ensured to achieve optimum frequency conversion in the SFG crystal. Precise tuning of the laser wavelength to the sodium D2 line is achieved by injection seeding of the 1064 nm pump laser with a single-frequency DFB laser. We have studied the performance of this laser for sodium lidar applications.Item Effect of GPA-16 on bilateral asymmetry, neuronal connectivity and learning behavior in C. elegansHan, PingABSTRACT Visceral organs structures and brain functions show asymmetric patterns in vertebrates including humans. Generally, the asymmetric pattern has a stereotypic laterality. Under some conditions, the laterality may be broken which can lead to abnormal structures and functions. Left-handedness is a type of brain functional laterality breaking condition. Research has shown that left-handers have increased performance in associative memory tasks compared to right-handed population. Also, left-handers tend to occupy the opposite ends of the performance spectrum, being more frequently observed in gifted individuals and in persons with psychosis. C. elegans is an excellent research model to evaluate to answer basic biological questions, including the influence of laterality variations. Even though C. elegans shows predominantly bilaterally symmetric external anatomy, however bilateral asymmetry is observed in its visceral organs and some of the neuron pairs. The stereotypic placement of anterior gut locates towards the left. Certain neuron pairs such as ASE-L and ASE-R display functional asymmetry. They express different kinds of genes and detect different kinds of water-soluble chemical cues. gcy-5 can only express on ASE-R, and gcy-5::GFP was used as ASE-R fluorescence marker in research. GPA-16 protein plays an important role in establishing and regulating asymmetric cell division during early stage of embryogenesis. Previous results demonstrated that gpa-16 mutants showing anatomical reversal in both embryos and adult worms. gpa-16 mutants show defects in both non-associative learning and associative learning. We examined the placement of ASE-R sensory neuron in gpa-16 mutants, and found out 22% ASE-R neurons were mis-localized. The mis-localized ASE-R has the potential to generate atypical neuronal circuitry and abnormal synaptic connectivity to downstream neurons, which could lead to the observed learning defects.Item Electrical Conductive Polymer FilmYang, DanWe report a conformal coating of thin electronic film using polyaniline (PANI), for which a highly bulk dopant, dinonylnaphthalenesulfonic acid (DNNSA), was used for synthesizing the electrically conductive polymer. Corresponding polymer was observed to show enhanced processability in organic solvents. Additional solution doping with m-cresol was found to be helpful for decreasing the surface resistance of the polymer film. The electrical resistance of corresponding films was observed to be 60.3 Ω/□ after post film doping processes were applied. The polymer layer was coated on a flexible aramid paper (NOMEX®, DuPont) varying the coating conditions for finding a sweet spot. Resultant polymer coats on the conformal substrate were observed to show promising surface resistance (140 Ω/□) showing any disadvantage in the mechanical integrity.Item Enzyme-assisted aqueous extraction of Njangsa (Ricinidendron heudelotti) seed oilArrey, Immaculate TabeSolvent extraction methods are widely used industrially to obtain oil from plant seeds, mostly due to their high efficiencies (90-98% w/w yield). However, consideration is being given to solvent-free extraction methods due to the growing concern that residual solvent in oil could pose significant health and environmental risks. As such, enzymatic extraction methods are receiving considerable interest in the oil industry due to their high specificity. Certain enzymes such as: hemicellulase, protease, pectinase and amylase are known to hydrolyze and degrade the cell wall of oilseeds, which significantly increases oil yield and quality upon extraction. Therefore, the aim of this study was to explore the effects of these four different enzymes on Njangsa (Ricinodendron heudeulotti) seed. A control without any enzyme was run in tadem. These treatments were compared to solvent-extraction using hexane. The percent yield of the enzyme-assisted extraction (28.37 - 36.0%) were significantly (p < 0.05) higher than that of the control (19.09%) but, lower than the hexane extraction (46.40%). Quality indices of Njangsa seed oil (NSO) such as: acid, peroxide, saponification, thiobarbituric acid, para-anisidine and free fatty acid values of the enzyme-assisted extraction samples were found to be significantly (p < 0.05) lower than the solvent extraction samples. Predominant fatty acids of NSO were alpha-eleostearic acid (α- ESA), linoleic, stearic, and oleic. NSO had a high polyunsaturated fatty acid content. The use of enzymes in Njangsa seed extraction were able to improve the quality parameters of Njangsa oil.Item Evaluating the effect of increasing salinity on the growth of root rot pathogens of common bean (phaseolus vulgaris l.)Lynch, Dylan ClaudeCommon bean (Phaseolus vulgaris L.) is the most important food legume valued for human consumption worldwide. It provides an important supply of dietary calories, vitamins, minerals, and contains as much as 30% protein for its seed size. It is also favored as a sustainable crop due to its ability to fix atmospheric nitrogen. Abiotic and biotic stress factors are major constraints to common bean production. Among the abiotic stress factors, soil salinity is the most devastating in terms of yield loss. Soil salinity is on the rise and it affects nodulation and crop growth, which result in yield losses. There are many contributors to soil salinity including natural weathering and human interventions. Biotic stress factors include a variety of pathogens causing diseases including root rots. The most prevalent root rot pathogens of common beans are Fusarium solani and Rhizoctonia solani where they can reduce yield as much as 100%. In the field, plants are confronted with a combination of biotic and abiotic factors that can affect their growth and productivity. However, studies on the combined effects of these factors on common bean are very limited and interactions between salinity and root rot pathogens and its overall effect on common bean are unavailable. Therefore, this study was set out to understand this gap using methods to evaluate the potential effect of increased salinity on fungal development including an assessment of radial mycelial growth, fungal biomass, and spore germination in-vitro using solid and liquid culture media amended with sodium chloride (NaCl). Severity of rots on common bean roots were also evaluated under increasing salt stress. Significant differences in mycelial growth for both pathogens was recorded. Dry fungal biomass production in liquid media was found to be significantly different in the NaCl-amended media for both pathogens compared to the non-amended control. Spore germination of F. solani was also negatively affected by the presence of NaCl in culture media. In the growth chamber experiments, the disease severity of both root rots was found to be significantly higher in the presence of the NaCl.Item Evaluation of Phytochemical Composition in Selected Medicinal Plants and Potential Application as Antimicrobial AgentSmith, Jallah ChukuFour medicinal plants native to Cameroon (C) and Kenya (K): Prunus africana (C) bark and root, P. africana (K) bark, Pausinystalia yohimbe bark, and Orthero root were screened to assess their phytochemical compositions and antioxidant activities. The plant parts were extracted using aqueous (80%) acetone, methanol, and ethanol (solvent: water, 80:20 v/v). The antioxidant capacity of the extracts was evaluated by their ability to scavenge free radicals using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and their antiradical power (ARP); trolox equivalent antioxidant capacity (TEAC) by utilizing 2,2′-azinobis-(3-ethylbenzothiaziline-6-sulfonate) (ABTS); and ferric reducing antioxidant power (FRAP). The total phenolic content (TPC) and total flavonoid content (TFC) were estimated by the Folin-Ciocalteu (FC) and aluminum-chloride (AlCl3) assays, respectively. Pigment content was determined spectrophotometrically, and phenolic acids were quantified by high performance liquid chromatography-photodiode array detector (HPLC-PAD) using eight aqueous solvent extracts with EC50 values (±0.125), in comparison with the standard (i.e., ascorbic acid). In addition, the antimicrobial activity was demonstrated using the agar disc diffusion assay followed by the measurement of the average zone of inhibition (ZOI) in which the first five aqueous solvent extracts in the order of decreasing antioxidant power were tested against two clinical foodborne bacteria (gram-negative E. coli and gram-positive S. aureus). The highest DPPH radical scavenging activity was found in P. africana (K) bark (95.77%; aqueous acetonic extract) though its aqueous methanolic extract exhibited the lowest antioxidant power with the highest effective concentration (EC50) and lowest ARP (7.298 mg/mL and 0.137), respectively; and its aqueous acetonic extracts also exhibited the lowest TPC and TFC, respectively (166.27 mg GAE/g and 9.60 mg RU/g). However, the highest EC50 and ARP (0.093 mg/mL and 10.753 respecively), and highest TPC (1131.70 mg GAE/g) were exhibited by the aqueous ethanolic extract of P. africana (C) bark while the highest ferric reducing capacity (11.33 mM Fe2+/g) and ABTS•+ radical scavenging activity (126.87 mM TE/g) was exhibited by the aqueous acetonic and aqueous methanolic extracts of P. yohimbe bark, respectively. Moreover, the highest TFC (61.33 mg RU/g) was also exhibited by the aqueous acetonic extract of P. yohimbe bark. Except for xanthophylls, the highest recorded pigment (61.92 mg/g) in this study was exhibited by the aqueous acetonic extract of Orthero root; the highest measure of all other pigments (chlorophyll a and b; total chlorophyll, lycopene, β-carotene, carotenoids, and anthocyanin) were exhibited by the aqueous acetonic extracts of P. yohimbe bark (9.16 and 22.46; 32.21, 2.78, 6.83, 20.08, and 0.53 mg/g, respectively). There was a significant positive correlation between TPC, TFC and DPPH, and a significant negative correlation between TPC and the other two antioxidant assays (FRAP and TEAC). Methyl 4-hydrocybenzoate and protocatechuic acid were detected and quantified in all the selected extracts, trans-sinapic acid (SIA) in P. africana (C) bark and root, and ferulic acid (FA) in P. africana root extract only. P. africana (C) bark and root extracts had the highest phenolic acid in all plant parts (i.e., SIA) with recorded values >100 mg/g which agrees with their spectrophotometrically determined high TPC. All aqueous solvent controls used for extraction, inhibited the growth of both E. coli and S. aureus while the sterile blank disc controls showed no inhibitory zone. Of all the tested extracts, both concentrations (50 and 100 mg/mL) of aqueous acetonic extracts of P. africana (C) bark exhibited no growth inhibiton against E. coli but an active to highly active inhibitory zone against S. aureus (8.0 to 17.33 mm). The highest growth inhibition was exhibited by the aqueous ethanolic extract of P. africana (C) bark against S. aureus (17.33 mm). These results clearly support the potential uses of these plant parts in a wide range of applications such as antimicrobials and antioxidants.Item Expression of QQS gene in transgenic cassava plant: implication in starch and protein contentDIAO, MARIEMECassava, Manihot Esculenta Crantz, is a dicot woody perennial shrub that belongs to Euphorbiaceae family. Over 800 million persons globally and 250 million sub-Saharan Africans rely on the starchy root crop cassava as their staple and major daily source of calories. It is a good source of calories for human and animals because of its richness in starch (30-60% dry matter). A typical cassava-based diet provides < 30% of the minimum daily requirement (MDR) for protein and 10% –20% for iron, zinc, and pro-vitamin A. Cassava deficiency in important nutrients especially proteins (1% to 2% dry weight basis) is a major cause of death and morbidity of resources poor people in developing countries who rely exclusively on this crop for their daily calorie source. Many attempts to use both traditional and biotechnology approaches to overcome protein deficiency in cassava have been proven to be unsuccessful. Our goal is to employ modern technologies to improve the health of millions of cassava consumers through the development of bioengineered cassava with increased protein levels. Qui-Quine Starch (QQS), a novel orphan gene unique to Arabidopsis thaliana was used in this study for the development of novel transgenic cassava plants exhibiting higher protein accumulation in their tissues. QQS is fully sequenced and available in the Genbank (GenBank#: NM_113975). This gene acts as a transcription factor and is known to impart carbon and nitrogen repartition into plant and therefore causing variations in protein, carbohydrate and even oil accumulation when expressed heterologously in transgenic plants. We expressed QQS in transgenic cassava plant via Agrobacterium-mediated genetic transformation with the goal to increase protein accumulation and study the eventual variations in plant morphology and biochemical profiles of other metabolites such as carbohydrates. A total of 10 transgenic cassava lines stably expressing QQS were regenerated and all well established in soil and only two lines (20%) showing malformed phenotype. Line R7 F) has the best growth vigor. Traditional PCR demonstrated that QQS gene was integrated in the genome of all the lines. RT-PCR data showed that the QQS gene is differentially expressed and that its transcript levels varied remarkably between shoot and root biomass of each transgenic line. Results of the nutritional profiles have shown that the expression of QQS gene into cassava plant increased leaf protein by 1.36% in line R’’’ (LA) L2 and root protein by 17.02% for the same line compared to their wild-type control plants and non-QQS expressers. Moreover, leaf soluble total carbohydrate increased by 51.76% in line R’’’ (G) L2 and root soluble total carbohydrate increased by 46.75% in line R7 (F). Regression analysis established no correlation between QQS transcript levels, carbohydrate, and protein content for transgenic root and shoot samples. Novel functionality of QQS to increase starch content in transgenic biomass is demonstrated. No change in the content of specific amino acids was observed among lines and plant parts. In addition, QQS expression revealed an increase in biomass, plant vigor, early in-vitro mini-tubers production for line R7 (F). However, it will be very critical to validate these observed changes in nutritional profiles of these young cassava plants expressing QQS by biochemically profiling these transgenic cassava plants at maturity once established in the field. Once validated in model cv60444, the transferability of this technology to consumer’s preferred cassava plant parts (tuberous roots and leaves) should be attempted.Item Extracting Fuzzy Rules to Compare Genetic Algorithm-Generated Motoneuron ModelsWilt, EricSpinal motoneurons that have been active for prolonged periods of time exhibit different electrical properties than their less active counterparts, suggesting that prolonged neuronal activity may change how electrical signals are transmitted through the neuron. Understanding how these spinal motoneurons integrate their input signals and modulate their output is important, with implications for rehabilitation, advanced prosthetics, brain-machine interfaces, humanoid robotics, and other biologically-inspired systems. To investigate what changes may take place within a spinal motoneuron following prolonged activity, a genetic algorithm was employed to generate two distinct groups of spinal motoneuron computational models. The first group (control) simulated less active neurons while the second group simulated neurons treated with high K+, which mimics persistent activation. The models had nine variable parameters, each a conductance related to a specific ion channel present in the motoneuron. To evaluate fitness for each computational model, fuzzy logic was used to assign membership in fuzzy sets corresponding to two separate objectives: current threshold and input resistance. To mine rules from the generated data, correlations were looked at between each fuzzy set and each parameter. While no rules were successfully mined in this research, some interesting results were produced. Some relationships that exist between parameters within the control (less active) models, do not seem to exist in the treated models. Relationships were also found between parameters that exist in both groups of models, suggesting a possible co-regulation of the genes which express those traits.Item Genetics and monitoring of the eastern oyster Crassostrea Virginica within Delaware inland baysBorsum, John ScottOyster enhancement to recover ecological benefits has been occurring since the late 1990s within the Delaware Inland Bays (DIBs) using a disease resistant line. Locally recruited oysters have been observed along hardened shorelines but limited quantitative information exists on the status of past or present DIBs sub-population. The goals of this study were to 1) assess the current genetic diversity of local DIBs oysters, 2) identify possible larval sources via genetic profiles, and 3) establish baseline measurements of oyster density along the selected rip-rap locations. Genetic diversity was assessed using eleven microsatellites markers to determine allele frequencies between two groups of spat collected from within the DIBs. Genetic profiles from the DIB groups were compared with a hatchery bred oysters used in local restoration and local wild Delaware Bay oysters, to determine possible source populations. Genetic results show similar allele frequencies among the two DIB groups which are more similar to local wild oysters than hatchery strains. Surveys among intertidal rip-rap habitats documented the current density and size frequency of oysters to evaluate future demographic changes. Oyster densities were generally low at the sites monitored in my study but the highest densities were observed within mid Indian River Bay. Monitoring oyster genetics and density needs to continue and expand throughout the DIBs to better understand local population dynamics and enhancement effects, as restoration continues and commercial scale shellfish aquaculture develops in the region.Item Germanium silicon tin oxide thin films for uncooled infrared detectorsCardona, JaimeMicrobolometer is a class of infrared detector whose resistance changes when the temperature changes. In this work, we deposited and characterized Germanium Silicon Oxide thin films mixed with Tin (Ge-Si-Sn-O) for uncooled infrared detection. Ge-Sn-O was deposited by co-sputtering of Sn and Ge-Si targets in an Ar+O environment using a radio frequency (RF) and direct current (DC) sputtering system. The electrical and optical properties of the thin films were tested to verify whether Ge-Si-Sn-O could be used as a sensing material in a microbolometer. From this testing, it was shown that with the an atomic composition consisting of Ge0.36Si0.04Sn0.11O0.43 the Ge-Si-Sn-O alloy could have a temperature coefficient of resistance (TCR) greater than -3.5 %/K, optical band gap of around 1 eV, and noise value of 300 μV/√Hz at 10Hz. With these values, besides the slightly high noise value, it has been determined that Ge-Si-Sn-O alloy is a viable candidate for use in microbolometer development.
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