Heavy metal bioaccumulation in aquatic organisms may occur through direct or indirect uptake routes. Research indicates that the significance of uptake route varies with contaminant and organism exposed. The relative importance of different metal sources in aquatic systems was investigated by exposing freshwater snails to dietary or dissolved sources of cadmium. Snails were exposed to control, contaminated food only, contaminated water only, and contaminated food and water treatments. During the 15-day exposure, samples were taken to determine Cd concentration in snail soft tissue, snail shell, algal food, and overlying water. Analyses of snail soft tissue and shells indicate that exposure route significantly affects Cd concentrations in the tissues. In both cases, dissolved Cd is the primary contributor to metal body burden.

Genomic modifications occur slowly across generations, whereas short-term epigenetic transgenerational inheritance of adaptive phenotypes may be immediately beneficial to large numbers of individuals, acting as a bridge for survival when adverse environments occur. In this study we used dietary exposure to crude oil as an example of an environmental stressor to assess its effects from the molecular to the organismal levels in piscine and avian animal models. In addition, we assessed the role of the parental exposures on their offspring F1 generation. The research developed in this dissertation has contributed to several areas of investigation including molecular biology, animal physiology, and evolutionary biology. The quantitative information from these studies may be utilized to supplement information regarding the proximate and ultimate effects of environmental stressors on fish and bird populations. Furthermore, this information may be used as additional support for understanding the conservation of the responses from the molecular to the whole organismal levels across the vertebrate taxa, as well as their implications for population survival and maintenance. Additionally, the zebrafish (Danio rerio), the Siamese fighting fish (Betta splendens) and the king quail (Coturnix chinensis) have proven to be excellent models to start building a strong basis for understanding the effects …

Sorghum plants excrete phenolic acids which reduce subsequent crop yields. These acids accumulate in field soil by combining with soil and clay particles to form stable complexes which remain until degraded by bacterial metabolism. The amount of phenolic acids in soil samples were obtained by gas chromatography measurements, while Azotobacter populations were obtained by plate counts in 40 sorghum field samples from Denton County, Texas. One can conclude that increasing the Azotobacter population in the soil increased the degradation rate of phenolic acids proportionally. It is proposed that seed inoculation will introduce selected strains of Azotobacter into the soil. The presence of Azotobacter should increase crop size in subsequent plantings.

Nucleotide pools were extracted and quantified from Pyr^+ and Pyr^- strains of P. aerucjinosa. Strains were grown in succinate minimal medium with and without pyrimidines, and nucleotides were extracted using trichloracetic acid (TCA; 6% w/v). The pyrimidine requirement was satisfied by uracil, uridine, cytosine or cytidine. Pyr^- mutants were starved for pyrimidines for two hours before nucleotide levels were measured. This starvation depleted the nucleotide pools which were restored to wild type levels by the addition of pyrimidines to the medium. When the pyrimidine analogue, 6-azauracil, known to inhibit OMP decarboxylase, was added to cultures of the wild type strain, the uridine and cytidine nucleotides were depleted to near zero. Thus, the nucleotide pool levels of Pseudomonas strains can be manipulated.

Putative cotton cDNA clones and cognate genomic clones for a palmitoyl-acyl carrier protein (ACP) thioesterase (PATE) and an osmotin-like pathogenesis-related 5 (PR5) protein have been isolated and characterized. PATE is a class B fatty acid thioesterase with specificity for saturated long-chain fatty acids such as palmitate, and is implicated as a key enzyme to be targeted for regulation of fatty acid synthesis in order to alter cotton seed oil profiles. A nearly full-length 1.7-kb cDNA clone was isolated using a hybridization probe derived from an Arabidopsis PATE cDNA clone designated TE 3-2. A 17-kb genomic segment encompassing the PATE gene was also isolated, which has six exons and five introns with high sequence identity with other FatB cDNA/gene sequences. The deduced PATE preprotein amino acid sequence of 413 residues has putative signal sequences for targeting to the chloroplast stroma. PR5 proteins called osmotins are made in response to fungal pathogen stress or osmotic stress (water deprivation or salt exposure). Osmotins may actually form pores in fungal membranes, leading to osmotic rupture and destruction of the fungal cells. A cotton osmotin-like PR5 cDNA insert of 1,052 base-pairs was isolated and shown to encode a preprotein of 242 amino acids and is …

The effects of single injections and daily oral administration of ethanol on plasma levels of ACTH, beta endorphin, and corticosterone in response to cold stress were examined. The long-term experimental animals were given 0.25 ml of 28% ethanol or water orally once a day, five days a week, for fourteen months. Plasma levels of ACTH, beta endorphin, and corticosterone were lower in alcohol-treated rats as compared with water-treated rats when exposed to cold stress. The effects of a single injection of ethanol significantly elevated plasma levels of all three hormones. Mortality in sham-treated males was higher than ethanol-treated.

Concern over sediment toxicity has increased the need for toxicity test information with organisms that inhabit sediments. Oligochaetes are exposed to toxicants through feeding and direct body contact with aquatic sediments. Chronic testing with oligochaetes has historically focused on tubificids with test lengths of one year or more to encompass several generations. Most naidid oligochaetes have generation times of three to seven days and could provide chronic information in a matter of weeks. The cosmopolitan distributed naidid, Pristina leidyi, was evaluated for use as a toxicity test organism. Results of research conducted includes culture methods, effects of temperature on reproduction, growth rates in a reference sediment, acute toxicity tests, and chronic toxicity tests.

The purpose of this study was to investigate the effects of Pb and hypoxia co-exposure on Pb toxicity and Ca homeostasis in early life stage (ELS) zebrafish (Danio rerio). Previous evidence indicates that exposure of ELS zebrafish to hypoxia (~20% air saturation) reduces Ca uptake, likely through down-regulation of the apical epithelial Ca channel (ECaC). Considering that Pb and Ca are known antagonists and compete for uptake pathways, it was hypothesized that co-exposure of Pb with hypoxia would decrease Pb toxicity by reducing Pb uptake (likely mediated through a reduced number of ECaCs). However, it was shown that at 96 hpf, whole body accumulation of both Pb and Ca was lower at 40% air saturation compared to 100% and 20% air saturation. This result closely aligned with the 96h LC50 results which showed the highest mortality of zebrafish at 40% compared to the other air saturation levels. This suggests that toxicity is likely the result of exacerbated hypocalcemia at 40% air saturation due to both Pb competition for Ca binding to Ca uptake channels/transporters, such as ECaC, and potentially reduced expression of such channels/transporters in response to this level of hypoxia. Overall, it appears that ELS zebrafish respond differentially to …

This research is designed to test how sublethal exposure to copper affects tadpole predator-escape behavior and how quickly tadpoles recover. After exposure, tadpoles were separated. Escape behavior was recorded for two-thirds of exposed tadpoles while one-third of the exposed population was measured weekly to determine growth and recovery. Control tadpoles were consumed within 15 minutes whereas those exposed to higher concentrations were consumed at a slower rate, which does not support the hypotheses. Although the rate of predation was lower, tadpoles exposed to higher Cu concentrations were on average, 1.47 cm in total body length. Those exposed to 0.93 mg/L averaged 0.86 cm. After being placed into clean water, treatment tadpoles recovered after 20 days.

Acclimation temperature had a significant effect on the lethality of copper to fathead minnows in replicated 96-hour lethality tests. Lowest median lethal copper concentrations (LC50) were recorded at 12 and 22°C, with LC50s at 5 and 32°C at least 140 μg/1 higher. This research found LC50 copper concentrations in the 300 to 500 μg/1 range and a polynomial relationship between LC50s and acclimation temperature. Following a 24-hour exposure to three sublethal concentrations of copper, critical thermal maxima (CTMax) were tested in minnows acclimated to four temperatures. Sublethal exposure to copper significantly decreased the CTMaxs relative to controls at three of the four temperatures. Control CTMaxs ranged from 28.6 to 40.4°C and increased 0.46°C for each 1°C increase in acclimation temperature.

Mefloquine hydrochloride is an antimalarial agent that has been used for the past 40 years. Numerous reports of neurological side effects have recently led the FDA to issue a strong warning regarding long-term neurological effects. This warning lead to the U.S. Army’s Special Forces and other components to discontinue its use in July of 2013. Despite reported adverse side effects, mefloquine remains in circulation and is recommended to travelers going to specific Asian countries. Mefloquine has been used as a treatment for those already infected with the malaria parasite (blood concentrations ranging from 2.1 to 23 µM), and as prophylaxis (blood concentrations averaging 3.8 µM) (Dow 2003). The purpose of this study was to quantify Mefloquine’s toxicity using spontaneously active nerve cell networks growing on microelectrode arrays in vitro and to identify compounds that alleviate or reduce toxic effects. The current literature on mefloquine toxicity is lacking electrophysiological data. These data will contribute to research on the mechanism of adverse side effects associated with mefloquine use. Sequential titration experiments were performed by adding increasing concentrations of mefloquine solution to cultured neurons. Network responses were quantified and reversibility was examined. In each network, activity decreases were normalized as a percent of …

In this project, the effects of dietary polyphenols on exercise-induced muscle damage and vascular health are examined. Dietary polyphenols exert well-known anti-inflammatory effects; however, how these effects are realized with respect to vascular health and EIMD is relatively unknown. I begin by reviewing the available literature surrounding the impact of three dietary polyphenols (curcumin, catechins, and quercetin) on inflammation associated with EIMD. It is well established that their primary means of anti-inflammation is through alterations of NF-κB and AP-1 transcription activities. Given this, their inclusion into training strategies seems reasonable. Consistent evidence is presented making a case for the anti-inflammatory effects of dietary polyphenols following EIMD. I follow this review up by completing an in-depth study on the consumption of curcumin prior to EIMD. I found curcumin (1000 mg/day) can reduce subjective soreness and decrease inflammation compared to placebo controls. To further understand the effects of dietary polyphenols on health, I investigate the effects of a four-week supplementation period of cocoa (catechins) on vascular. I concluded that atherogenic risk in obese women is reduced after consumption of cocoa. In addition to these experimental projects, I developed two novel methods that can be used to investigate vascular health (EMP concentration) and …

The biosynthesis of pyrimidines in Pseudomonas putida was investigated. In this study, pyrimidine requiring mutants were isolated by conventional mutagenesis and enrichment. The strains required exogenously supplied pyrimidines for growth and were found by enzyme assays to be deficient for the product of the pyrB gene encoding the enzyme aspartate transcarbamoylase. None of the intermediates of the pathway could supply the auxotrophic requirement of the strain; only preformed pyrimidines, metabolized via salvage pathways could suffice. Pyrimidine limitation in the mutant caused a slight but significant fifty per cent increase in expression of all the de novo biosynthetic enzymes. Pyrimidine starvation's effect on nucleotide pool levels was examined in the mutant and caused a marked swelling of the purine nucleotide pools.

The enzyme that catalyzes the committed step in pyrimidine biosynthesis, aspartate transcarbamoylase, has been compared in selected endospore-forming organisms and in morphologically similar control organisms. The ATCases and pyrimidine salvage from Sporosarcina ureae, Sporolactobacillus inulinus, Lactobacillus fermentum, and Micrococcus luteus were compared to those of Bacillus subtilis. While the ATCases from Sporosarcina ureae, Sporolactobacillus inulinus, and L. fermentum were found to exhibit characteristics to that of Bacillus with respect to molecular weight and kinetics, M. luteus ATCase was larger at approximately 480 kDa. Furthermore, pyrimidine salvage in Sporosarcina ureae and M. luteus was identical to those of B. subtilis, while pyrimidine salvage of Sporolactobacillus inulinus and L. fermentum resembled that of the pseudomonads.

This article analyzes the bioremediation of the soil contaminated by hydrocarbons (HYCOS), the importance of biostimulation with a detergent (DEGE) or biodetergent (BIODET) and the inconsistencies generated by their application.

An accurate fire model is a useful tool in predicting the behavior of a prescribed fire. Simulation of fire requires an extensive amount of data and can be accomplished best using GIS applications. This paper demonstrates integrative procedures of using of ArcGIS™, ERDAS Imagine™, GPS, and FARSITE© to predict prescribed fire behavior on the Kaibab-Paiute Reservation. ArcGIS was used to create a database incorporating all variables into a common spatial reference system and format for the FARSITE model. ArcGIS Spatial Analyst was then used to select optimal burn sites for simulation. Our predictions will be implemented in future interagency efforts towards vegetative restoration on the reservation.

Research estimated toxicity of refuse-derived fuel fly ash (RDF-FA) on two earthworms species, Lumbricus terrestris and Eisenia foetida. Specific objectives were to: (1) Compare their 14-day LC50s under light and dark conditions; (2) separate toxicity due to osmotic, pH and physical factors from that of heavy metal contaminants; (3) compare relative differences of artificial soil and commercial soil as exposure media for evaluating toxicity to earthworms. The 14-d LC50s for L. terrestris in dark and light were 57.0 and 48.34 % RDF-FA, and 59.25 and 41.00 % RDF-FA for E. foetida using artificial soil. All of the toxicity resulted from heavy metals within the RDF-FA. Using L. terrestris, the LC50s for artificial soil and commercial soil were 52.30 and 64.34%.

The goal of this study was to build on the historic use of the avian model of development and also to further the knowledge of autonomic nervous system (ANS) regulation of cardiovascular function in vertebrates. Vasoactive drugs sodium nitroprusside, a vasodilator and phenylephrine, a vasoconstrictor were used to study the correlation of cardiovascular function relationship with nerve activity, both sympathetic and parasympathetic (vagal). Additionally, ANG II was used to assess its effects on vagal inhibition. The present study shows that pharmacologically-induced hypertension is associated with a fall in mSNA, indicating that the capacity for sympathetic autonomic cardiovascular regulation is established by late incubation however, late-stage embryonic chickens did not show a significant increase in mSNA during hypotension. The hypotensive response of the embryo was not accompanied by the expected inhibition of vagal discharge; however a slight but insignificant reduction in vagal discharge was noted. When vagal efferent output was isolated, a significant drop in vagal efferent activity was noted in response to hypotension. The present study showed late-stage embryonic chickens lack a vagal response to hypertension in both efferent and sensory limbs. In this study, vagal discharge was reduced from baseline levels in response to Ang II. Collectively, the present …

I assessed fish community data collected by the Oklahoma Conservation Commission from 82 minimally impaired wadeable reference streams in eastern Oklahoma to determine whether existing aquatic ecoregions provide the best framework for spatial classification for the development of biological assessment methods and biocriteria. I used indirect ordination and classification to identify groups of sites that support similar fish communities. Although correspondence was observed between fish assemblages and three montane ecoregions, the classification system must be refined and expanded to include major drainage basins and physical habitat attributes for some areas to adequately partition variance in key measures of biological integrity. Results from canonical correspondence analysis indicated that substrate size and habitat type were the primary physical habitat variables that influenced the fish species composition and community structure.

Pseudomonas fluorescens does not appear to regulate the enzymes of de novo pyrimidine biosynthesis at the level of gene expression. Little or no apparent repression of pyr gene expression is observed upon addition of exogenous pyrimidines to the growth medium. The Escherichia coli pyrBI genes for aspartate transcarbamoylase (ATCase) were sized down and cloned into the broad host range plasmid, pKT230. Upon introduction into a P.fluorescenspyrB mutant strain, ATCase showed repression in response to exogenously fed pyrimidine compounds. Thus, it was possible to bring about changes in pyrimidine nucleotide pool levels and in transcriptional regulation of gene expression at the same time.

Superbursts (SBs) are large, seemingly spontaneous activity fluctuations often encountered in high density neural networks in vitro. Little effort has been put forth to define and analyze SBs which are paroxysmal bursting discharges. Through qualitative and quantitative means, I have described specific occurrences of superbursting activity. A complex of paroxysmal bursting has been termed a "superburst episode," and each individual SB is a "superburst event" which is comprises a fine burst structure. Quantitative calculations (employing overall spike summations and coefficient of variation (CV) calculations), reveal three distinct phases. Phase 1 is a "build up" phase of increasingly strong, coordinated bursting with an average of a 17.6% ± 13.7 increase in activity from reference. Phase 2, the "paroxysmal" phase, is comprised of massive coordinated bursting with high frequency spike content. Individual spike activity increases by 52.9% ± 14.6. Phase 3 is a "recovery phase" of lower coordination and an average of a 50.1% ± 35.6 decrease in spike production from reference. SBs can be induced and terminated by physical manipulation of the medium. Using a peristaltic pump with a flow rate of 0.4ml/min, superbursting activity ceases approximately 28.3 min after the introduction of flow. Alternatively, upon cessation of medium flow superbursting …

Chicken embryos were chronically exposed to the ?1- blocker atenolol during one of three stages: mesonephros (E7-E9), mesonephros-metanephros (E11-E13), or metanephros (E15-E17). Mesonephros group hearts were larger than all other groups (P < 0.01). Mesonephros and metanephros group kidneys were larger than all remaining groups (P < 0.0001). The mesonephros group nephron number was ~40% lower than control values (P = 0.002). Glomerular areas were 26% and 18% larger than the control group in the mesonephros and metanephros groups, respectively (P < 0.001). These data suggest an E7-E9 critical window of cardiovascular and renal development for atenolol. Acute atenolol exposure in E15 embryos showed an increase in mean arterial pressure with all but the highest dose. All doses significantly decreased heart rate.

The role of operant behavior in the metabolism of brain 5-hydroxytryptamine (5-HT) turnover was investigated. Two and one-half hours following the administration of 150 mg/kg of para-chlorophenylalanine (PCPA), a specific inhibitor of tryptophan hydroxylase, levels of 5-HT were compared in sedentary and performing rats. Whole brain levels of serotonin were reduced in both responding and sedentary animals; however, differences between these groups were not statistically significant. The drug induced decrease in 5-HT levels was accompanied by a significant decrease in session responding. The degree of suppressed responding could be correlated with the level of 5-HT following PCPA, suggesting that the metabolism of serotonin is in part modulated by the rate of responding as maintained by the operant schedule.

Growth and element assimilation was investigated in post oak seedlings exposed to four different treatment combinations of fertilization and ectomycorrhizal inoculation. Element concentration in excised leaves was analyzed via particle induced X-ray emission spectrometry with a 1.8 MeV proton macrobeam. Mean growth was significantly different across the treatment groups as well as mean concentration of Mg, Al, S, K, Ca, Fe, Cu, and Zn. The data suggest that fertilization rather than mycorrhizal inoculation had a stronger influence on plant growth and nutrient uptake. A follow up study was conducted with a 3 MeV microbeam. A 850 μm2 scanned area of a post oak leaf produced topographical maps of 11 elements.