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(1 - 7 of 7)
- Title
- THE ACUTE TOXICITY OF GROUND RECYCLED AUTOMOBILE TIRES ON AQUATIC LIFE WITH MODEL SPECIES P. PROMELAS.
- Creator
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Baldassari, Trillian, Cooper, David, University of Central Florida
- Abstract / Description
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Used tires have the potential for becoming popular in pollution control media used in stormwater applications including pervious pavement sub bases, green roof growth media, and upflow filters. Using tire crumb to decrease nutrients can minimize impacts on ecology while reducing the human footprint left by used tires. However, if tire crumb is not examined for toxicity, the ecological balance could unknowingly be disrupted. This research tested the acute toxicity of tire crumb in aquatic...
Show moreUsed tires have the potential for becoming popular in pollution control media used in stormwater applications including pervious pavement sub bases, green roof growth media, and upflow filters. Using tire crumb to decrease nutrients can minimize impacts on ecology while reducing the human footprint left by used tires. However, if tire crumb is not examined for toxicity, the ecological balance could unknowingly be disrupted. This research tested the acute toxicity of tire crumb in aquatic systems by finding the Lethal Concentration for 50% kill (LC50). Using an extreme tire crumb load, P. promelas (fathead minnow) were exposed to leachates created with tire crumb and several different types of water including distilled water, tap water, and detention pond water. For distilled and tap water, the addition of tire crumb increased the survival of P. promelas. For detention pond water, the addition of tire crumb decreased the survival of P. promelas, though only enough to find an LC50 for detention pond water influenced immediately by stormwater runoff. An LC50 was found when 100 percent tire crumb filtrate is prepared with 25 grams of tire crumb per liter of detention pond water collected directly after a storm. The LC50 found is resultant of a tire crumb load significantly higher than what can be expected in the environment. Based on this research, tire crumb is considered non-threatening to aquatic fish and safe to use with detention pond water.
Show less - Date Issued
- 2008
- Identifier
- CFE0002282, ucf:47850
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002282
- Title
- Turbidity Removal Efficiency and Toxicity Issues Associated with the Chitosan-Based Dual Bio-Polymer Systems.
- Creator
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Hernandez, Rylee, Chopra, Manoj, Wanielista, Martin, Randall, Andrew, University of Central Florida
- Abstract / Description
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Stormwater runoff can be a great concern in the State of Florida due to the impact the quality of the runoff water can have on the natural water bodies. Stormwater runoff can carry pollutants and sediments which can cause both physical and biological risks in an aquatic ecosystem such as a lake, river, or pond. Polymers, namely the chitosan-based dual polymer system, can be used remove the sediment from this runoff to ensure the safety of the state's water bodies. Three soils are used in this...
Show moreStormwater runoff can be a great concern in the State of Florida due to the impact the quality of the runoff water can have on the natural water bodies. Stormwater runoff can carry pollutants and sediments which can cause both physical and biological risks in an aquatic ecosystem such as a lake, river, or pond. Polymers, namely the chitosan-based dual polymer system, can be used remove the sediment from this runoff to ensure the safety of the state's water bodies. Three soils are used in this testing: AASTO soil classifications A-3(sandy soil) and A-2-4 (silty-sand), and a soil with a fine-grained limerock component. An optimum dose of the chitosan-based dual polymer system is first determined using jar testing. The optimum dose is the dose that reduces the final turbidity to 29 NTUS or below and creates significant flocs. The under dose and over dose are calculated based on the optimum dose. Using these dosages, field scale tests are conducted using two different treatment methods: a semi-passive treatment method and a passive treatment method. Whole effluent toxicity and residual chitosan tests are then conducted on the effluent from the field scale treatment methods. The passive treatment method is the best field scale treatment method when using the silty-sand and the soil with a fine-grained limerock component. The semi-passive treatment method is the best field scale treatment method when using the sandy soil. The passive treatment method with the silty-sand achieves a final turbidity of 123.9 NTUS (88.45% removal). The passive treatment method with the soil with a fine-grained limerock component achieves a final turbidity of 132 NTUS (83.86% removal). The semi-passive treatment method with the sandy soil achieves a final turbidity of 31.43 NTUS (82.04% removal). There is only significant toxicity associated with the tests using the effluent from the passive treatment method with the soil with a fine-grained limerock component which only uses the cationic polymer.
Show less - Date Issued
- 2012
- Identifier
- CFE0004301, ucf:49482
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004301
- Title
- TRANSLOCATION OF THE CHOLERA TOXIN A1 SUBUNIT FROM THE ENDOPLASMIC RETICULUM TO THE CYTOSOL.
- Creator
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Taylor, Michael, Teter, Ken, University of Central Florida
- Abstract / Description
-
AB-type protein toxins such as cholera toxin (CT) consist of a catalytic A subunit and a cell-binding B subunit. CT proceeds through the secretory pathway in reverse, termed retrograde trafficking, and is delivered to the endoplasmic reticulum (ER). In order for the catalytic A1 subunit to become active it must separate from the rest of the holotoxin, and this dissociation event occurs in the ER lumen. CTA1 assumes an unfolded conformation upon dissociation from the holotoxin and is...
Show moreAB-type protein toxins such as cholera toxin (CT) consist of a catalytic A subunit and a cell-binding B subunit. CT proceeds through the secretory pathway in reverse, termed retrograde trafficking, and is delivered to the endoplasmic reticulum (ER). In order for the catalytic A1 subunit to become active it must separate from the rest of the holotoxin, and this dissociation event occurs in the ER lumen. CTA1 assumes an unfolded conformation upon dissociation from the holotoxin and is recognized by ER- associated degradation (ERAD), a quality control system that recognizes and exports misfolded proteins to the cytosol for degradation by the 26S proteasome. CTA1 is not degraded by the 26S proteasome because it has few sites for poly-ubitiquination, which is recognized by the cap of the 26S proteasome for degradation. Thus, CTA1 escapes the degradation of ERAD while at the same time using it as a transport mechanism into the cytosol. It was originally proposed that CTA1 is thermally stable and that ER chaperones actively unfolded CTA1 for translocation to the cytosol. In contrast, we hypothesized that the dissociated CTA1 subunit would unfold spontaneously at 37°C. This study focused on the three conditions linked to CTA1 instability and translocation: (i) CTA1 dissociation from the holotoxin, (ii) the translocation-competent conformation of CTA1, and (iii) the extraction of CTA1 from the ER into the cytosol. Disruption of any of these events will confer resistance to the toxin. The original model suggested that PDI actively unfolds CTA1 to allow for translocation. However, Fourier transform infrared spectroscopy (FTIR) and surface plasmon resonance (SPR) data we have gathered demonstrated that PDI dislodges CTA1 from the rest of the holotoxin without unfolding CTA1. Once released by the holotoxin, CTA1 spontaneously unfolds. PDI is thus required for the toxicity of CT, but not as an unfoldase as originally proposed. CTA1 must maintain an unfolded conformation to keep its translocation-competent state. Based on our model, if CTA1 is stabilized then it will not be able to activate the ERAD translocation system. Our SPR and toxicity results demonstrated that treatment with 4-phenylbutyrate (PBA), a chemical chaperone, stabilizes the structure of CTA1. This stabilization resulted in a decrease in translocation from the ER to the cytosol and a block of intoxication, which makes it a viable candidate for a therapeutic. Because CTA1 exits the ER in an unfolded state, there must be a driving force for this translocation. We hypothesized that Hsp90, a cytosolic chaperone, is responsible for the translocation of CTA1 across the membrane. Previous research had shown Hsp90 to be present on the cytosolic face of the ER and had also shown that Hsp90 will refold exogenously added proteins that enter the cytosol. Using drug treatments and RNAi, we found that Hsp90 is required for the translocation of CTA1 from the ER lumen to the cytosol, a brand new function for this chaperone. We have provided evidence to support a new, substantially different model of CTA1 translocation. CTA1 does not masquerade as a misfolded protein in order to utilize ERAD for entry into the cytosol; it actually becomes misfolded and is treated as any other ERAD substrate. The spontaneous unfolding of CTA1 is the key to its recognition by ERAD and ultimately its translocation into the cytosol. Host factors play very important roles in intoxication by AB toxins and are targets for blocking intoxication.
Show less - Date Issued
- 2011
- Identifier
- CFE0003733, ucf:48784
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003733
- Title
- Embryonic Stem Cell-Derived Exosomes Inhibit Doxorubicin-Induced Pyroptosis in Cell Culture Models.
- Creator
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Tavakoli Dargani, Zahra, Singla, Dinender, Masternak, Michal, Siddiqi, Shadab, Steward, Robert, University of Central Florida
- Abstract / Description
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Doxorubicin (Dox) is a potent chemotherapeutic drug used for the treatment of various cancers. Unfortunately, its use is limited as Dox induces adverse cardiotoxicity (DIC) and muscle toxicity (DIMT), which are mediated through oxidative stress, ER stress, and inflammation. However, it remains unknown whether Dox induces an inflammation mediated cell death, called (")pyroptosis("). The current study is designed to determine whether Dox induces pyroptosis in cardiac and muscle cell culture...
Show moreDoxorubicin (Dox) is a potent chemotherapeutic drug used for the treatment of various cancers. Unfortunately, its use is limited as Dox induces adverse cardiotoxicity (DIC) and muscle toxicity (DIMT), which are mediated through oxidative stress, ER stress, and inflammation. However, it remains unknown whether Dox induces an inflammation mediated cell death, called (")pyroptosis("). The current study is designed to determine whether Dox induces pyroptosis in cardiac and muscle cell culture models. Moreover, the protective effects of embryonic stem cell-derived exosomes (ES-Exos) in inhibiting pyroptosis will also be determined. For this purpose, we designed two different cell culture models using H9c2 cadiomyoblasts and Sol 8 cells. For the DIC model, H9c2 were exposed to Dox to induce pyroptosis and then treated with exosomes. Cells were divided into 4 groups: Control, Dox, Dox+ES-Exos, and Dox+MEF-Exos (negative control). Furthermore, to generate the DIMT model, Sol 8 cells were incubated with Dox+THP-1 conditioned medium (TCM) to induce toxicity and inflammation, which was followed by exosomes treatment. We assigned cells into 5 groups: Control, Dox+TCM, Dox+TCM+ES-Exos, Dox+TCM+MEF-Exos (negative control), and Dox+TCM+ES-Exos+GW4869 compound (exosomes inhibitor, negative control). Our data shows that Dox treatment significantly increased pyroptotic marker expression including TLR-4, NLRP3, caspase-1, IL1-?, Caspase-11, and gasdermin-D as well as increased pro-inflammatory TNF-? and IL-6 expression in H9c2 cells. There was also a significant increase in caspase-1, IL1-?, and IL-18 expression in Dox+TCM treated Sol 8 cells. Conversely, increased pyroptosis and inflammation post-Dox treatment were inhibited by ES-Exos in both culture models. No significant changes observed upon MEF-Exos and GW4869 compound treatments. In conclusion, our data shows Dox induces pyroptosis and inflammation within cardiac and skeletal muscle cells, which can be inhibited following treatment with ES-exosomes. This is a novel study with new mechanistic observations on the pathophysiological role of pyroptosis in Dox-induced cardio and muscle toxicities.
Show less - Date Issued
- 2018
- Identifier
- CFE0007416, ucf:52700
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007416
- Title
- Near-road Dispersion Modeling of Mobile Source Air Toxics (MSATs) in Florida.
- Creator
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Westerlund, Kurt, Cooper, Charles, Radwan, Ahmed, Randall, Andrew, Hall, Steven, University of Central Florida
- Abstract / Description
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There is a growing public concern that emissions of mobile source air toxics (MSATs) from motor vehicles may pose a threat to human health. At present, no state or federal agencies require dispersion modeling of these compounds, but many agencies are concerned about potential future requirements. Current air pollution professionals are familiar with Federal Highway Administration (FHWA) and U.S. Environmental Protection Agency (EPA) requirements for dispersion modeling to produce predicted...
Show moreThere is a growing public concern that emissions of mobile source air toxics (MSATs) from motor vehicles may pose a threat to human health. At present, no state or federal agencies require dispersion modeling of these compounds, but many agencies are concerned about potential future requirements. Current air pollution professionals are familiar with Federal Highway Administration (FHWA) and U.S. Environmental Protection Agency (EPA) requirements for dispersion modeling to produce predicted concentrations for comparison with appropriate standards. This research examined a method in which the potential near-road concentrations of MSATs were calculated. It was believed that by assessing MSATs in much the same way that are used for other pollutants, the model and methods developed in this research could become a standard for those quantifying MSAT concentrations near-roadways.This dissertation reports on the results from short-term (1-hour) and long-term (annual average) MSATs dispersion modeling that has been conducted on seven intersections and seven freeway segments in the state of Florida. To accomplish the modeling, the CAL3QHC model was modified to handle individual MSAT emissions input data and to predict the concentrations of several MSATs around these roadway facilities. Additionally, since the CAL3MSAT model is DOS based and not user-friendly, time was invested to develop a Windows(&)#174; graphical user interface (GUI). Real-world data (traffic volumes and site geometry) were gathered, worst-case meteorology was selected, mobile source emission factors (EFs) were obtained from MOVES2010a, and worst-case modeling was conducted. Based on a literature search, maximum acceptable concentrations (MACs) were proposed for comparison with the modeled results, for both a short-term (1-hour) averaging time and a long-term (1-year) averaging time.Results from this CAL3MSAT modeling study indicate that for all of the intersections and freeway segments, the worst-case 1-hour modeled concentrations of the MSATs were several orders of magnitude below the proposed short-term MACs. The worst-case 1-year modeled concentrations were of the same order of magnitude as the proposed long-term MACs.The 1-year concentrations were first developed by applying a persistence factor to the worst-case 1-hour concentrations. In the interest of comparing the predicted concentrations from the CAL3MSAT persistence factor approach to other dispersion models, two EPA regulatory models (CAL3QHCR and AERMOD) with the ability to account for yearly meteorology, traffic, and signal timing were used. Both hourly and annual MSAT concentrations were predicted at one large urban intersection and compared for the three different dispersion models. The short-term 1-hour results from CAL3MSAT were higher than those predicted by the two other models due to the worst-case assumptions. Similarly, results indicate that the CAL3MSAT persistence factor approach predicted a worst-case annual average concentration on the same order of magnitude as the two other more refined models. This indicated that the CAL3MSAT model might be useful as a worst-case screening approach.
Show less - Date Issued
- 2013
- Identifier
- CFE0004772, ucf:49804
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004772
- Title
- Evaluation of The Biodegradability and Toxicity of PCA and mPCA.
- Creator
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Rueda, Juan, Randall, Andrew, Duranceau, Steven, Yestrebsky, Cherie, University of Central Florida
- Abstract / Description
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The main types of hypergolic propellants used at Kennedy Space Center (KSC) are hydrazine (HZ) and monomethylhydrazine (MMH). HZ and MMH are classified as hazardous materials and they are also known to be potentially carcinogenic to humans; therefore, handling these substances and their waste is strictly regulated. The wastes streams from HZ and MMH have been estimated to be the main hazardous wastes streams at KSC. Currently at KSC these wastes are first neutralized using citric acid and...
Show moreThe main types of hypergolic propellants used at Kennedy Space Center (KSC) are hydrazine (HZ) and monomethylhydrazine (MMH). HZ and MMH are classified as hazardous materials and they are also known to be potentially carcinogenic to humans; therefore, handling these substances and their waste is strictly regulated. The wastes streams from HZ and MMH have been estimated to be the main hazardous wastes streams at KSC. Currently at KSC these wastes are first neutralized using citric acid and then they are transported on public roads for incineration as hazardous materials. A new method using alpha ketoglutaric acid (AKGA) was proposed to treat HZ and MMH wastes. From the reaction of AKGA with HZ and MMH two stable products are formed, 1,4,5,6-tetrahydro-6-oxo-3-pyridazinecarboxylic acid (PCA) and l-methyl-1,4,5,6-tetrahydro-6-oxo-3-pyridazinecarboxylic acid (mPCA), respectively.The cost of purchasing AKGA is greater than the cost of purchasing citric acid; thus, AKGA can only become a cost effective alternative for the treatment of HZ and MMH wastes if the products of the reactions (PCA and mPCA) can be safely disposed of into the sewage system without affecting the treatment efficiency and effluent quality of the wastewater treatment plant (WWTP). In this research mPCA and PCA were analyzed for acute toxicity using fish and crustaceans as well as their effect on the wastewater treatment efficiency and viability using AS microbes, and their biodegradability by AS organisms. Acute toxicity on fish and crustaceans was investigated according to the methods for acute toxicity by USEPA (USEPA Method EPA-821-R-02-012) using Ceriodaphnia dubia (96 hours) and Pimephales promelas (96 hours) as the test organisms. The effect of mPCA and PCA in the treatment efficiency and viability were estimated from respiration inhibition tests (USEPA Method OCSPP 850.3300) and heterotrophic plate counts (HPCs). Lastly, the biodegradability of mPCA and PCA was assessed using the Closed Bottle Test (USEPA Method OPPTS 835.3110). For mPCA, the 96 hours LC50 for C. dubia was estimated at 0.77 (&)#177; 0.06 g/L (with a 95% confidence level) and the NOEC was estimated at 0.5 g/L. For P. promelas, the LC50 was above 1.5 g/L but it was noticed that mPCA had an effect on their behavior. Abnormal behavior observed included loss of equilibrium and curved spine. The NOEC on the fish was estimated at 0.75 g/L. PCA did not exhibit a significant mortality on fish or crustaceans. The LC50 of PCA in P. promelas and C. dubia was (>) 1.5 g/L and the NOEC was 1.5 g/L for both organisms. An Inhibitory effect on the heterotrophic respiration of activated sludge organisms was not observed after exposing them for 180-min to PCA and mPCA at concentrations of up to 1.5 g/L compared to the blank controls. Overall the impact of PCA and mPCA on total respiration rates was small, and only observed at 1,500 mg/L if at all. The difference was apparently caused by inhibition of nitrification rather than heterotrophic inhibition. However due to the variability observed in the measurements of the replicates, it is not possible to firmly conclude that PCA or mPCA at 1,500 mg/L was inhibitory to nitrification.Based on the results from the HPCs, mPCA and PCA did not affect the viability of heterotrophic organisms at 750 mg/L. In the BOD-like closed bottle test using a diluted activated sludge mixed liquor sample, the AS microorganisms were capable of biodegrading up to 67% of a 2 mg/L concentration of PCA (with respect to its theoretical oxygen demand, or ThOD) in 28 days. No biodegradation was observed in the samples containing 2 and 5 mg/L of mPCA after 28 days of incubation using a diluted activated sludge mixed liquor sample as inoculum.The results of this study show that mPCA is more toxic than PCA to Ceriodaphnia dubia and Pimephales promelas. However neither mPCA nor PCA had an effect on the heterotrophic respiration of an AS mixed liquor sample at 1.5 g/L and there was probably no significant inhibition of the nitrification respiration. Samples of PCA and mPCA at 2 and 5 mg/L could not be completely degraded (with respect to their total theoretical oxygen demand) by dilute AS biomass during a 28 day incubation period. mPCA did not show significant degradation in the two different biodegradation tests performed.
Show less - Date Issued
- 2013
- Identifier
- CFE0004744, ucf:49779
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004744
- Title
- Determining differential effects of Interleukin-2 on innate and adaptive immune cells in lymphoid organs and the gastrointestinal Tract.
- Creator
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Singh, Ayushi, McKinstry, Karl, Naser, Saleh, Copik, Alicja, University of Central Florida
- Abstract / Description
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Interleukin-2 (IL-2) is a pleiotropic cytokine demonstrated to be effective in treating cancer. However, the clinical use of IL-2 can be associated with severe side effects including gastrointestinal toxicity (GT). Similar GT symptoms are observed in inflammatory diseases such as CD (CD). Interestingly mounting evidence indicates a role for IL-2 in CD, but the underlying mechanisms are unknown. Indeed, studies on the in-vivo activities of IL-2 have mostly focused on secondary lymphoid organs...
Show moreInterleukin-2 (IL-2) is a pleiotropic cytokine demonstrated to be effective in treating cancer. However, the clinical use of IL-2 can be associated with severe side effects including gastrointestinal toxicity (GT). Similar GT symptoms are observed in inflammatory diseases such as CD (CD). Interestingly mounting evidence indicates a role for IL-2 in CD, but the underlying mechanisms are unknown. Indeed, studies on the in-vivo activities of IL-2 have mostly focused on secondary lymphoid organs and immune cells associated with them. Very few studies have addressed how IL-2 signals impact populations of immune cells in the gut. Here, we aim to identify and compare the effects of systemic IL-2 administration on six major leukocyte population and their subsets in mice using multicolor flow cytometry. While we confirmed previously observed changes in specific immune cell populations in the spleen, very few changes were seen in the gut and gut associated lymphoid tissues. Unexpectedly, a sharp decline was seen in B cells, most notably in Peyer's Patches, in mice treated with IL-2. Our data furthermore indicates that B cells in IL-2 treated mice undergo enhanced apoptosis in Peyer's Patches. Some studies suggest that changes in B cells may contribute to development of CD. Thus, this study may aid in defining ways in which IL-2 can contribute to disease etiology, and lead to novel treatments for CD.
Show less - Date Issued
- 2019
- Identifier
- CFE0007865, ucf:52777
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007865
