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Role of N-Acylethanolamines in Plant Defense Responses: Modulation by Pathogens and Commercial Antimicrobial Stressors

Description: N-acyl ethanolamines (NAEs) are a class of lipids recently recognized as signaling molecules which are controlled, in part, by their degradation by fatty acid amide hydrolase (FAAH). On the basis of previous studies indicating increased NAE levels in a tobacco cell suspension-xylanase elicitor exposure system and the availability of FAAH mutants, overexpressor and knockout (OE and KO) genotypes in Arabidopsis thaliana, further roles of NAEs in A. thaliana plant defense was investigated. The commonly occurring urban antimicrobial contaminant triclosan (TCS) has been shown to suppress lipid signaling associated with plant defense responses. Thus, a second objective of this study was to determine if TCS exposure specifically interferes with NAE levels. No changes in steady state NAE profiles in A. thaliana-Pseudomonas syringae pv. syringae and A. thaliana-flagellin (bacterial peptide, flg22) challenge systems were seen despite evidence that defense responses were activated in these systems. There was a significant drop in enoyl-ACP reductase (ENR) enzyme activity, which catalyzes the last step in the fatty acid biosynthesis pathway in plants, on exposure of the seedlings to TCS at 10 ppm for 24 h and decreased reactive oxygen species (ROS) production due to flg22 in long term exposure of 0.1 ppm and short term exposure of 5 ppm. However, these responses were not accompanied by significant changes in steady state NAE profiles.
Date: August 2010
Creator: Vadapalli, Vatsala
Partner: UNT Libraries

Effects of Triclosan, Triclocarban, and Caffeine Exposure on the Development of Amphibian Larvae.

Description: Triclosan and triclocarban are antimicrobials found in numerous consumer products, while caffeine is the most commonly consumed stimulant by humans. This study was undertaken to determine the effects of triclosan, triclocarban, and caffeine on the development and physiology of amphibian larvae. LC50 values of triclosan and triclocarban were determined after 96 hours for three North American larval species: Acris crepitans blanchardii, Bufo woodhousii woodhousii, Rana sphenocephala, and for a common amphibian developmental model: Xenopus laevis. Amphibian larvae were most sensitive to triclosan and triclocarban exposure during early development based upon 96-hour LC50 values. Heart rates for X. laevis and North American larvae exposed to triclosan were variable throughout development. However, significantly lower heart rates were observed in all larvae exposed to triclocarban. Metabolic rates of X. laevis and R. sphenocephala larvae exposed to triclosan were significantly affected in larvae exposed to ½ LC50 and the LC50 concentration. Metabolic rates of X. laevis larvae exposed to triclocarban were significantly affected by exposure to ½ LC50 concentrations in three of four stages investigated. No significant differences were observed in North American larvae exposed to triclocarban. Tissue uptake, lipid uptake, tissue bioconcentration factor (BCF) and lipid BCF of triclosan and triclocarban were investigated in three developmental stages of X. laevis, and in one developmental stage of B. woodhousii woodhousii, and R. sphenocephala. For most tissue and lipid uptake values, a significant increase was observed as exposure concentration increased. Tissue and lipid BCF values were dependent upon both stage and species. Chronic and acute effects of caffeine were determined in X. laevis larvae. Acute 96-hour LC50 values in four developmental stages were > 75,000 ug L-1 caffeine and heart rates were significantly different at the two earliest developmental stages. Larvae chronically exposed to caffeine reached metamorphosis at the same time as controls. Changes in ...
Date: August 2009
Creator: Palenske, Nicole Marie
Partner: UNT Libraries

Evaluation of the Developmental Effects and Bioaccumulation Potential of Triclosan and Triclocarban Using the South African Clawed Frog, Xenopus Laevis

Description: Triclosan (TCS) and triclocarban (TCC) are antimicrobials found in U.S. surface waters. This dissertation assessed the effects of TCS and TCC on early development and investigated their potential to bioaccumulate using Xenopus laevis as a model. The effects of TCS on metamorphosis were also investigated. For 0-week tadpoles, LC50 values for TCS and TCC were 0.87 mg/L and 4.22 mg/L, respectively, and both compounds caused a significant stunting of growth. For 4-week tadpoles, the LC50 values for TCS and TCC were 0.22 mg/L and 0.066 mg/L; and for 8-week tadpoles, the LC50 values were 0.46 mg/L and 0.13 mg/L. Both compounds accumulated in Xenopus. For TCS, wet weight bioaccumulation factors (BAFs) for 0-, 4- and 8-week old tadpoles were 23.6x, 1350x and 143x, respectively. Lipid weight BAFs were 83.5x, 19792x and 8548x. For TCC, wet weight BAFs for 0-, 4- and 8-week old tadpoles were 23.4x, 1156x and 1310x. Lipid weight BAFs were 101x, 8639x and 20942x. For the time-to-metamorphosis study, TCS showed an increase in weight and snout-vent length in all treatments. Exposed tadpoles metamorphosed approximately 10 days sooner than control tadpoles. For the hind limb study, although there was no difference in weight, snout-vent length, or hind limb length, the highest treatment was more developed compared to the control. There were no differences in tail resorption rates between the treatments and controls. At relevant concentrations, neither TCS nor TCC were lethal to Xenopus prior to metamorphosis. Exposure to relatively high doses of both compounds resulted in stunted growth, which would most likely not be evident at lower concentrations. TCS and TCC accumulated in Xenopus, indicating that the compound has the potential to bioaccumulate through trophic levels. Although TCS may increase the rate of metamorphosis in terms of developmental stage, it did not disrupt thyroid function and metamorphosis in ...
Date: December 2010
Creator: King, Marie Kumsher
Partner: UNT Libraries

Formation of microvilli

Description: Microvilli on cells frequently display a regular hexagonal packing pattern. We present here a model for how this regular pattern is established and how the microvilli are extruded from the cell. The model is based on the viscoelastic properties of the actomyosin gel in the cell cortex. 16 refs., 7 figs.
Date: January 1, 1985
Creator: Oster, G.F.; Murray, J.D. & Odell, G.M.
Partner: UNT Libraries Government Documents Department

Principles and major agents in clinical oncology chemotherapy

Description: This paper provides a brief classification of drugs available for veterinary chemotherapy, as well as justifications for their use. Some common neoplasia and the drugs of choice for their treatment are described. A listing by class of systemic chemotherapeutic agents, their mode of action, tumors responsive to the drugs, precautions and common adverse effects and mode of administration is provided. 2 tabs. (MHB)
Date: October 1, 1991
Creator: Weller, R.E.
Partner: UNT Libraries Government Documents Department

Molecular biological enhancement of coal desulfurization

Description: The objective of this project is to produce one or more microorganisms capable of removing the organic and inorganic sulfur in coal. The specific technical objectives of the project are to: clone and characterize the genes encoding the enzymes of the 4S'' pathway (sulfoxide/sulfone/sulfonate/sulfate) for release of organic sulfur from coal; return multiple copies of genes to the original host to enhance the biodesulfurization activity of that organism; transfer this pathway into a fast-growing chemolithotrophic bacterium; and conduct a batch-mode optimization/analysis of scale-up variables. This report presents the results of research at Battelle during the 5th Quarterly Report period beginning on June 15, 1990. 1 ref., 6 figs., 4 tabs.
Date: September 14, 1990
Creator: Litchfield, J.H.; Fry, I.; Wyza, R.E.; Palmer, D.T.; Zupancic, T.J.; Conkle, H.N. (Battelle, Columbus, OH (USA)) et al.
Partner: UNT Libraries Government Documents Department

Role of protein synthesis in the repair of sublethal x-ray damage in a mutant Chinese hamster ovary cell line

Description: A temperature-sensitive mutant for protein synthesis, CHO-TSH1, has been compared to the wild-type cell, CHO-sC1, in single- and split-radiation-dose schemes. When the exponentially growing TS mutant and the wild-type cells were treated at 40/sub 0/C for up to 2 hrs prior to graded doses of x rays, the survival curves were identical and were the same as those obtained without heat treatment. If the cultures were incubated at 40/sup 0/C for 2 hrs before a first dose and maintained at 40/sup 0/C during a 2 hr dose fractionation interval, repair of radiation damage was reduced in the mutant compared to the wild type. These observations implied that a pool of proteins was involved in the repair of sublethal x-ray damage. However, if repair was measured by the alkaline-unwinding technique under the same time and temperature schemes, no difference in the kientics of DNA strand rejoining was observed. Misrepair processes may permit restoration of DNA strand integrity but not allow functional repair. The effect of diminished repair under conditions of inhibition of protein synthesis was found to be cell-cycle dependent in survival studies with synchronized mutant cell populations. Repair was found to be almost completely eliminated if the temperature sequence described above was applied in the middle of the DNA synthetic phase. Treatment of cell populations in the middle of G/sub 1/-phase yielded repair inhibition comparable to that observed with the asynchronous cells. Splitdose experiments were done using pre-incubation with cycloheximide to chemically inhibit protein synthesis. WT cells and TS cells were treated with cycloheximide at 35/sup 0/C for 2 hrs before a first dose and during a 2 hr dose fractionation interval. 23 figs., 7 tabs.
Date: April 1, 1985
Creator: Yezzi, M.J.
Partner: UNT Libraries Government Documents Department

Anticancer chemotherapy

Description: This document examines chemotherapeutic agents for use in veterinary oncology. It lists some of the most common categories of chemotherapeutic drugs, such as alkylating agents and corticosteroids. For each category, the paper lists some example drugs, gives their mode of action, tumors usually susceptible to the drug, and common side effects. A brief discussion of mechanisms of drug resistance is also provided. (MHB)
Date: October 1, 1991
Creator: Weller, R.E.
Partner: UNT Libraries Government Documents Department

The degradation of organic dyes by corona discharge

Description: Several dyes in water were individually exposed to corona discharge. Light absorbance decreased for all organic dyes with time. Absorbance losses with methylene blue, malachite green, and new coccine were studied. The loss of color was followed using an in situ colorimeter and the effects of varying the current, voltage, gas phase, stirring rates, salinity, and electrode spacing were investigated. The highest reaction rates were observed using the highest current, highest voltage (up to 10kV), highest stirring rate, lowest salinity, smallest electrode spacing, and an environment containing enhanced levels of oxygen. Current was higher in the presence of nitrogen than in the presence of oxygen (for the same voltage), but the reaction of methylene blue did not proceed unless oxygen was present. These results help identify conditions using corona discharge in which dyes, and potentially other organics, can be destroyed. 22 refs., 5 figs.
Date: February 1, 1992
Creator: Goheen, S.C.; McCulloch, M.; Durham, D.E. & Heath, W.O.
Partner: UNT Libraries Government Documents Department

Clinical aspects of accidents resulting in acute total body irradiation

Description: That the management of whole body radiation injury involves: (1) watchful waiting, (2) observation of the hematologic parameters, (3) use of antibiotics, platelet red cell and possibly granulocyte transfusions, (4) administration of hemopoietic molecular regulators of granulopoiesis, and (5) bone marrow transplantation as the last line of defense. The clinical indication for the preceding will not be discussed, since this will be a subject of later speakers in this conference. Certainly, if a radiation casualty is fortunate enough to have an identical twin, a marrow transplant may be lifesaving and certainly can do no harm to the patient, and there is little risk to the donor.
Date: January 1, 1988
Creator: Cronkite, E.P.
Partner: UNT Libraries Government Documents Department

ELISA-Based Segregation of Adult Spring Chinook Salmon for Control of Bacterial Kidney Disease, Annual Report FY 1990.

Description: Bacterial kidney disease (BKD), caused by Renibacterium salmoninarum (RS), is a serious disease of salmonid fish worldwide. The disease has a major impact on spring chinook salmon populations in the Columbia River system. There is strong evidence that RS can be transmitted from parent to progeny, and segregation of progeny based on levels of antigen detected in adult fish may obviate this mode of transmission. Results from the second year of a four year study to investigate segregation of broodstock as a tool for controlling BKD are presented. To segregate the progeny of adult fish infected with RS we have used enzyme-linked immunosorbent assays (ELISAs) optimized in the first year of this project. Gametes from fish either injected with erythromycin or receiving no antibiotic injection were successfully segregated into groups having either high or low levels of the RS soluble antigen. Screening of eggs from infected adults has not revealed any detectable antigen present in the egg tissue. Development of a rapid, field ELISA has been accomplished this year. The field ELISA utilizes monoclonal antibodies currently employed in the monoclonal antibody-based ELISA. The sensitivity of the field ELISA approaches that of the monoclonal ELISA, and has been tested on 150 adult chinook salmon. A high correlation exists between samples assayed by the monoclonal ELISA, field ELISA, and direct FAT. An alternative system for detecting RS soluble antigen, the Western blot, has also been improved. Using a chemiluminescent substrate, the sensitivity of detection has been increase 50--100 fold. 16 refs., 15 figs., 2 tabs.
Date: December 1, 1990
Creator: Winton, James R. & Kaattari, Stephen L.
Partner: UNT Libraries Government Documents Department

FDA Approved Registration of Erythromycin for Treatment of Bacterial Kidney Disease (BKD) in Juvenile and Adult Chinook Salmon : Annual Report, Reporting Period March 10, 1989 to March 9, 1990.

Description: Erythromycin is a therapeutic substance useful against bacterial kidney disease in salmon. In 1989 we began a multi year project to learn more about erythromycin applied to juvenile and adult salmon, with the goal of achieving registration of erythromycin with the US Food and Drug Administration. To begin the study, we studied the pharmacokinetics of erythromycin administered to both adult and juvenile chinook salmon. We monitored blood plasmas time curves from individual adult fish injected with two forms of injectable erythromycin using one of three routes of administration. In addition, we began experiments to evaluate hatchery applications of erythromycin to individually marked adult salmon, and we recovered blood tissues from these fish at the time of spawning. To determine how to use erythromycin in juvenile salmon, we evaluated the adsorption and elimination of erythromycin applied arterially and orally to individual juvenile fish. In feeding trials we determined the palatability to juvenile chinook salmon of feed made with one of two different carriers for erythromycin thiocyanate. 35 refs., 4 figs. , 3 tabs.
Date: April 1, 1991
Creator: Moffitt, Christine A.
Partner: UNT Libraries Government Documents Department

In-vitro and in-vivo characterization of ruthenium-bleomycin compared to cobalt- and copper-bleomycin

Description: Bleomycin (BLM) has undergone extensive investigation both as a cancer chemotherapeutic agent, and as a carrier for radionuclides for tumor imaging. The available methods or the radionuclides used, however, have had limited effectiveness. Although labeling of BLM with /sup 103/Ru has been reported earlier, we carried out a study to develop a more reproducible method of labeling particularly for use with Brookhaven Linac Isotope Producer produced /sup 97/Ru. Ruthenium-97 has favorable physical properties that make it ideal for imaging applications: decay by electron capture; ..gamma.. 216 keV, 85%; t/sub 1/2/ 2.9 d. A novel method based on the reduction of Ru/sup 3 +/ to Ru/sup 2 +/ using stannous chloride was investigated for labeling BLM with /sup 97/Ru and/or /sup 103/Ru. In-vitro and in vivo comparisons of the product(s) with /sup 57/Co and /sup 67/Cu-labeled BLM were also carried out. 4 refs., 3 tabs.
Date: January 1, 1986
Creator: Shao, H.S.; Meinken, G.E.; Srivastava, S.C.; Slosman, D.; Sacker, D.F.; Som, P. et al.
Partner: UNT Libraries Government Documents Department

Cytometry of mammalian sperm

Description: Male germ cells respond dramatically to a variety of insults and are important reproductive dosimeters. Semen analyses are very useful in studies on the effects of drugs, chemicals, and environmental hazards on testicular function, male fertility and heritable germinal mutations. The accessibility of male cells makes them well suited for analytical cytology. We might automate the process of determining sperm morphology but should not do so solely for increased speed. Rather, richer tangible benefits will derive from cytometric evaluation through increased sensitivity, reduced subjectivity, standardization between investigators and laboratories, enhanced archival systems, and the benefits of easily exchanged standardized data. Inroads on the standardization of assays for motility and functional integrity are being made. Flow cytometric analysis of total DNA content of individual sperm is an insensitive means to detect exposure to reproductive toxins because of the small size and low frequency of the DNA content errors. Flow cytometry can be applied to determine the proportions of X- and Y-sperm in semen samples.
Date: October 11, 1983
Creator: Gledhill, B.L.
Partner: UNT Libraries Government Documents Department

Role of base damage in aberration formation: interaction of aphidicolin and x-rays

Description: The base analog cytosine arabinoside (CA) is an inhibitor of DNA synthesis that is able to induce chromosomal aberrations not only in the DNA synthetic (S) phase of the cell cycle but in cells in the pre- (G/sub 0/ or G/sub 1/) and in the post-DNA-synthetic (G/sub 2/) phases of the cell cycle as well. Incubation of human peripheral lymphocytes in CA following either G/sub 0/ or G/sub 2/ x irradiation causes a synergistic increase in chromosomal aberration frequency. CA is believed to preferentially inhibit DNA polymerase ..cap alpha... It is suggested that it is inhibition of the repair of x-ray-induced base damage that is responsible for the synergistic effect on chromosomal aberration production observed with x-ray and CA treatment of human peripheral lymphocytes. It has also been observed that CA induces sister chromatid exchanges (SCE) in mammalian cells when present during normal DNA replication and that it also interacts synergistically with uv in the induction of SCE. A number of other inhibitors of DNA synthesis were also tested, one, aphidicolin (APC), did produce effects similar to CA at the same concentration. Aphidicolin is a tetracyclic diterpinoid that inhibits the growth of eukaryotic cells by inhibition of DNA synthesis. This action has been shown to result from specific inhibition of DNA polymerase ..cap alpha.., but not of polymerases ..beta.. or ..gamma... Unlike CA, it seems likely that APC inhibits by binding to and inactivating the DNA-..cap alpha.. polymerase complex. Because both CA and APC are ..cap alpha.. polymerase inhibitors and because both interact synergistically with uv in the production of SCE, studies were conducted to determine whether APC also shares other cytogenetic properties of CA. Results to date have shown that, like CA, APC is clastogenic in both G/sub 0/ and G/sub 2/, and it also interacts synergistically with x ...
Date: January 1, 1981
Creator: Bender, M.A. & Preston, R.J.
Partner: UNT Libraries Government Documents Department

Investigation of molecular mechanisms in photodynamic action and radiobiology with nanosecond flash photolysis and pulse radiolysis. Progress report, October 1, 1980-September 30, 1981

Description: Laser flash photolysis experiments have led to a new mechanism for the ultraviolet photolysis of aqueous tryptophan (Trp), indole (Ind) and certain indole derivatives. Excitation at 265 nm leads to photoionization via a pre-fluorescent state with thermal activation. A new formula is proposed for predicting enzyme inactivation quantum yields. The predictions are in good agreement with measurements on six important enzymes at 254 nm and 280 nm. Kinetics models have been developed and tested for important stages in the photosensitization of DNA to near-ultraviolet radiation by furocoumarin compounds currently used for PUVA therapy (psoralen plus UV-A) of psoriasis and other human skin diseases. Experiments on photobinding of psoralen (Ps) and 8-methoxypsoralen (8-MOP) to calf thymus DNA are consistent with the assumption that equilibrium dark complexing of the furocoumarin to the DNA is a precondition for the formation of covalent monoadducts and cross-links. Singlet oxygen generation by furocoumarins has been investigated with liposomes and human erythrocytes (rbc). Results obtained with 3-carbethoxypsoralen (3-CPs), an experimental alternate PUVA sensitizer claimed to be non-tumorigenic, show that 3-CPs interacts with liposome and rbc membranes in the dark. Studies on photosensitization of egg lecithin liposomes by methylene blue (MB) incorporated in the membrane have led to the new result that membrane lysis is a two-stage process. The first stage induced by red light irradiation leads to membrane damage initiated by O/sub 2/*. Membrane lysis takes place in the dark, second stage under the action of mild hydrodynamic stress, such as slow gas bubbling.
Date: June 1, 1981
Creator: Grossweiner, L I
Partner: UNT Libraries Government Documents Department

Role of DNA polymerase. cap alpha. in chromosomal aberration production by ionizing radiation

Description: Aphidicolin is a tetracyclic diterpinoid fungal antibiotic which inhibits DNA synthesis in eukaryotic cells by interfering specifically with DNA polymerase ..cap alpha.., apparently by binding to and inactivating the DNA-polymerase ..cap alpha.. complex. We have shown that aphidicolin, like other inhibitors of DNA synthesis, both induces chromosomal aberrations in human peripheral lymphocytes, and, as a post-treatment, interacts synergistically with x rays to produce greatly enhanced aberration yields. The present experiments explore the effects of aphidicolin in human lymphocytes in the post-DNA-synthetic G/sub 2/ phase of the cell cycle. These experiments utilized labeling with tritiated thymidine to positively identify cells in the S phase at the time of treatment, and used serial colcemid collections and fixations to determine aberration yields over as much of the G/sub 2/ phase as feasible. Because DNA polymerase ..cap alpha.. is the only DNA synthetic or repair enzyme known to be affected by aphidicolin, we infer that this enzyme is directly involved in the repair of DNA lesions which can result in visible chromosomal aberrations. (DT)
Date: January 1, 1983
Creator: Bender, M.A.
Partner: UNT Libraries Government Documents Department

On-line assessment of mixing in an acid waste neutralization system

Description: The acid was neutralization system at Sandia National Laboratories treats process waste water from the Microelectronics Development Laboratory (MDL). The system consists of two 9,500 liter stirred tank reactors in series with an approximate feed rate of 3.17 L/s. The tanks are equipped with 320 W mixers with single impellers. pH sensors in each tank control acid and caustic delivery pumps. Sporadic excursions outside the required range of pH 5 to 11 were observed. Tracer experiments using methylene blue dye were performed during normal MDL operations to assess mixing in the individual reactors and the system. Tracers were injected as instantaneous pulses into the reactors and time dependent concentrations were measured in the effluent. Dimensionless exit age distributions were obtained which were similar to distributions for continuous stirred tank reactors (CSTR). These age distributions were extended to predict fluoride concentrations. The data indicate a separate fluoride collection system will be required to meet local environmental safety and health (ES H) regulations. Results from these tracer experiments have lead to cost effective design improvements in our neutralization system. 4 refs., 8 figs., 1 tab.
Date: January 1, 1990
Creator: Brown, N.E.; Resnick, P.J. & Bickel, T.C.
Partner: UNT Libraries Government Documents Department