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  Partner: UNT Libraries
 Department: Department of Biology
Changes in Gene Expression Levels of the Ecf Sigma Factor Bov1605 Under Ph Shift and Oxidative Stress in the Sheep Pathogen Brucella Ovis
Brucella ovis is a sexually transmitted, facultatively anaerobic, intracellular bacterial pathogen of sheep (Ovis aries) and red deer (Cervus elaphus). Brucella spp. infect primarily by penetrating the mucosa and are phagocytized by host macrophages, where survival and replication occurs. At least in some species, it has been shown that entry into stationary phase is necessary for successful infection. Brucella, like other alphaproteobacteria, lack the canonical stationary phase sigma factor ?s. Research on diverse members of this large phylogenetic group indicate the widespread presence of a conserved four-gene set including an alternative ECF sigma factor, an anti-sigma factor, a response regulator (RR), and a histidine kinase (HK). The first description of the system was made in Methylobacterium extorquens where the RR, named PhyR, was found to regulate the sigma factor activity by sequestering the anti-sigma factor in a process termed "sigma factor mimicry." These systems have been associated with various types of extracellular stress responses in a number of environmental bacteria. I hypothesized that homologous genetic sequences (Bov_1604-1607), which are similarly found among all Brucella species, may regulate survival functions during pathogenesis. To further explore the involvement of this system to conditions analogous to those occurring during infection, pure cultures of B. ovis cells were subjected to environments of pH (5 and 7) for 15, 30, and 45 minutes and oxidative (50mM H2O2) stress, or Spermine NONOate for 60 minutes. RNA was extracted and converted to cDNA andchanges in transcript levels of the sigma factor Bov1605 were measured using qPCR. Preliminary results indicate that under the exposure to Spermine NONOate there was little change in expression, but under oxidative stress expression of the sigma factor Bov1605 was 4.68-fold higher than that expressed under normal conditions. These results suggest that the sigma factor Bov1605 may be involved in oxidative stress defense during infection. Under acid stress (pH5), Bov1605 was found to be upregulated at 15 and 30 minutes, but after 45 and 60 minutes the time decreased.
Pressure-Flow Relationships in the Isolated Cerebral Circulation of the Dog
The purpose of this investigation is to determine the pressure-flow relationships in the isolated canine cerebral vascular bed. These relationships in vessels which supply an organ surrounded by bone are theoretically influenced by limiting factors which are not present in those vessels surrounded by soft tissue. An evaluation of the extent of these limitations is essential to thorough understanding of the dynamics of the cerebral vascular bed.
Effects of X-Irradiation on Water and Ion Flux in Isolated Roots
Due to the relatively small amount of work concerning radiation, it was thought feasible to use ionizing radiation as a tool to study the relationship between water and salt flux in isolated root systems. Moreover, the more quantitative potometric method lends itself well to such a study, since the two processes can be followed simultaneously. the aims of this study, therefore, were 1) to determine effects of X-irradiation on water, calcium and potassium flux in excised onion roots; 2) to determine the dose levels required for producing permeability changes; 3) to investigate the nature of radiation damage to root systems; and 4) to attempt to shed light on the relation between water transport and ion movement in root systems.
A Study of a Branchiobdellid from Denton County, Texas
In this study, branchiobdellids were collected from crayfish captured from two adjacent sites in Denton County, Texas. Identification of the branchiobdellid, Cambarincola vitrea Ellis, was first made and then work was extended to include several topics of ecological interest.
The Autecology of Celtis Laevigata in Flood Plain Forests of Denton County, Texas
This thesis describes the present nature of one facet of some of the flood plain forest stands in Denton County, Texas. The specific purpose was to demonstrate the presence or absence of difference between the Celtis laevigata (commonly known as the hackberry, southern hackberry or sugarberry) populations in stands on Denton Creek and Elm Fork of the Trinity River.
Photoreactivation Studies on Azotobacter vinelandii ATCC 12837
This thesis was written to study photoreactivation in different physiological conditions of the vegetative cell as well as the photoreactivation of the two morphological states of the Azotobacter cell: the vegetative cell and the cyst.
The Production of Fragile Cysts by an Aberrant Strain of Azotobacter Chroococcum Isolated from Soil
The purpose of this study is to determine if a strain of Azotobacter chroococcum isolated from the soil in northern Louisiana produces cysts which are as resistant to deleterious agents as those produced by previously reported strains os Azotobacter.
Serological Characteristics of Morphologically and Biochemically Similar Streptomyces Species
It is the purpose of this investigation to test for serological characteristics of six Streptomyces species which exhibit identical and/or very closely similar morphological and biochemical characteristics.
The Dispersal of Algae and Protozoa by Selected Odonata
This study was designed to show what dissemules may be carried by selected genera of Odonata, where the dissemules may be predominantly carried on the selected insects and to relate the behavior of the selected Odonata to frequency of occurrence of micro-organisms on the insects.
Some Effects of X-Irradiaion on the Adrenal Response to Hypothalamic Stimulation in Rats
Exactly where in the hypothalamus is the adrenal-pituitary response to X-irradiation "triggered" or initiated? Moreover, does ionizing radiation act directly on specific centers in the brain or does it act indirectly via the production of some humoral agents? Finally, what role does the hypothalamus play in the radiation-syndrome? The purpose of the present study was to attempt to answer these questions by determining the effects of two stressor agents, X-irradiation and electrical stimulation applied either singly or together, on the activity of the adrenal-pituitary axis. The parameters measured were changes in plasma corticosterone, in circulating eosinopihils, and in adrenal gland weight.
A Screening of Fungi for Metabolites Inhibitory to the Growth of Bloom-Forming Blue-Green Algae
Since many approaches to dealing with algal blooms are inefficient, expensive, or harmful, it was concluded that a biologically-synthesized chemical agent, specifically inhibitory to pre-bloom algal cells, might prove helpful in controlling algal blooms. Fungi were chosen as the biological entities to investigate for such a chemical.
Effects of X-Irradiation on Na22 Efflux in Isolated Nerves
The purpose of this study was twofold: 1) to present experimental data on changes in permeability of fibers during irradiation using Na22 as the tracer isotope, and 2) to attempt to correlate these findings with the electrical changes observed.
An Evaluation of the United States Soil Conservation Service Program of Grassland Recovery on the Land Utilization Project in Wise county, Texas
This investigation was undertaken in order to evaluate the United States Soil Conservation Service program of grassland recovery on the land utilization project in Wise County, Texas.
Toxicity Studies of Aquatic Actinomycetes
Since Actinomycetes have been isolated from finished public drinking water, it is believed that the organisms are unaffected by the chlorination and flocculation of water treatment plants and pass as spores through the filters into the general distribution system. For this reason it was deemed imperative to study the toxic effects of these organisms.
Observations on the Life History of the Brown Spider, Loxosceles Reclusa Gertsch and Muliak
This research was undertaken primarily to further elucidate the life history of this medically important spider. Special attention was given to rearing experimental spiders under as near-natural environmental conditions as possible.
Capillary Permeability to Narrow-Range Macromolecular Dextrans at Normal and Hypobaric Pressures
In view of its varied concepts and interpretations, and because of the discrepancies produced by the previous utilization of polydispersed dextrans, a study using extremely narrow-range molecular weight dextran fractions was initiated to reevaluate and consolidate some of the aspects of capillary permeability. A portion of the study was performed under decreased barometric pressure in order to clarify further some of the mechanisms involved in particulate transfer across the capillary endothelial membranes. Gel filtration procedures augmented the study as an assessment of the polydispersity effects of the dextrans employed.
Actinoplanes Philippinensis: Effect of Carbon Sources on Zoospore Production
Actinomycetes are able to utilize a great variety of carbohydrates, like sugar. The particular kind of sugar and its concentration has decisive effect on the growth of microorganisms. The proper nutritional media aids also in the production of spores. Based on this generalization, that the growth and sporulation of microorganisms are greatly influenced by the nature and the concentration of carbohydrates, an attempt has been made to study Actinoplanes philippinensis with respect to this influence.
Studies of Selected Cyanophyte Response to Varying Geosmin Concentrations
The purpose of this investigation is to determine the effect of varying geosmin concentrations on the growth of selected cyanophytes which did not produce a notable odor in culture.
Distribution, Size, Condition, and Food Habits of Selected Fishes in a Reservoir Receiving Heated Effluent from a Power Plant
This study was undertaken in order to provide further insight into the effects of artificial heating on the fisheries of a small reservoir in the Southwest. The following specific objectives were established: (1) to map the reservoir for the distribution of heated water, (2) to determine the distribution of selected species of sports, rough, and forage fish in areas affected by the effluent and in areas not affected, (3) to compare size and condition of selected species of fish from areas affected by the effluent to size and condition of fish from areas not affected, and (4) to compare food habits of channel catfish in areas affected by the effluent to the food habits of channel catfish in areas not affected.
Nitrogen Accretion on a Lacustrine Plain
The purpose of the investigation was to locate the plant population which had the greatest impact on soil nitrogen in a successional sequence from newly deposited alluvia to a mature streamside forest, and to evaluate the pioneer populations in terms of their annual nitrogen contribution.
Purification and Characterization of Ascaris Suum Aldolase : An Initial Phylogenetic Study of Aldolases
An efficient purification procedure of Ascaris suum muscle utilizing ion exchange column chromatography has been developed.
Isolation, Purification, and Characterization of Aldolase from Human Heart
Aldolase from human heart has been purified 128-fold to a final specific activity of 11.52 units per mg. The purification procedure employed column chromatography on phosphocellulose.
Electron Microscopy of Vesicles Present in Bacterial Lysates of Escherichia Coli
It is the purpose of this thesis to report further studies on the vesicles appearing in phage lysates of Escherichia coli, phage attachment to these vesicles, and the presence of similar vesicles in lysozyme and penicillin lysed cultures.
Factors Affecting Slime Formation in a Spray Irrigation Waste Disposal System
It was the purpose of this investigation to determine (1) what organisms are associated with the formation of this slime layer, (2) if certain chemical factors in the environment either enhance or retard formation of the slime layer, (3) whether or not there are certain chemical factors which are detrimental to slime formation, yet not detrimental to purification, or that perhaps enhance purification, (4) whether or not there are chemical factors which enhance purification of the effluent without preventing slime formation, and (5) what effects the chemical treatments have on the microbial flora of the soil system.
Heat Resistance in Vegetative Cells and Cysts of Azotobacter
The purpose of the current study is to determine something of the nature of the heat resistance in Azotobacter, if in fact this is found to exist. An attempt is made to determine the specific physiological state associated with heat resistance as well as to resolve this resistance quantitatively.
Drift of Aquatic Insects in the Brazos River, Texas
The objective of this study was to elucidate the nature and extent of drift by the aquatic insect populations of the Brazos River, Texas.
A Study of Malate Dehydrogenase Isoenzymes in the Midge Larva Glyptotendipes barbipes
Two isoenzymes of malate dehydrogenase were isolated and partially purified from the midge larva Glyptotendipes barbipes. Differential centrifugation followed by cellulose acetate and polyacrylamide gel electrophoresis revealed one isoenzyme associated with the mitochondrial fraction and another form found only in the cytoplasm.
Effects of X-irradiation on Potassium Flux in Isolated Nerves
The purpose of this study, therefore, was threefold in nature: (1) to determine the effects of x-irradiation on the influx and efflux of potassium in compound nerve fibers (2) to attempt to relate the radiation-induced changes in electrical activity with potassium flux and (3) to use the information obtained to gain insight into the possible cellular site (s) of radiation insult to compound nerves.
Effects of Visible Monochromatic Radiations on Growth of Pith Callus Tissue of Pelargonium Zonale
It was the purpose of the investigation to determine the effects of selected high intensity monochromatic radiations on the growth of pith callus tissue of Pelargonium zonale, variety Enchantress Fiat. In addition, the extent of cell differentiation was to be determined for tissues grown under each experimental treatment.
The Effect of Carbon Monoxide on the Growth of an Aquatic Streptomycete
The major purpose of this investigation was to determine the effect of carbon monoxide on the development of various morphological phases of a single isolate of the aquatic streptomycetes and to elucidate the physiological differences between terminal respiration in the primary and secondary stages. A secondary purpose was to repeat the work of Michael Lee Higgins involving the effect of anaerobiosis on the growth of the organism.
A Study of the Southern Spotted Channel Catfish, Ictalurus Punctatus (Rafinesque)
The purpose of the present study is to present research data on the propagation of the southern spotted channel catfish.
Water and Ion Eflux in Isolated Onion Roots
The aims of this study were: (1) to determine simultaneously by means of a micro-potometric method the rates of water and various isotopic ion effluxes from isolated onion roots; (2) to determine and compare the effects of metabolic inhibitors on both processes simultaneously; (3) to ascertain the similarity or dissimilarity of mechanisms involved with these two processes; (4) to ascertain the role of active metabolism in each of these processes; (5) to shed light on possible gearing mechanism(s) between metabolic and transport processes.
A Comparative Study of the D Cells of Certain Mammalian Islets of Langerhans
The purpose of this study is to describe and compare the D cells of the islets of Langerhans in six different species of mammals.
Assimilation of Organic Carbon by Aquatic Actinomycetes
There were two purposes of this investigation: the first was to develop a method for studying spore germination, hyphal growth and mycelial development of the aquatic actinomycetes under the microscope so that the life cycle of this organism could be continuously followed. The second purpose was to determine the rate of carbon utilization from various types of nutritional sources, and to correlate this with the colony development and spore formation.
The Life Cylce of an Aquatic Actinomycete
The purpose of this investigation was an attempt to clarify the relatives taxonomic position of and to formulate some of the basic cyclic morphological and physiological processes occurring in an aquatic actinomycete possessing streptomycetal characteristics.
Effects of Selected Phytohormones on the Growth and Morphology of Escherichia Coli
The present investigation was undertaken as a preliminary study to learn the response of Escherichia coli cells grown under identical experimental conditions to various concentrations of indoleacetic acid, gibberellic acid, and kinetin alone, and in combination with one another.
Application of Fluorescent Antibody Methods for the Enumeration and Identification of Bacilus Cereus
This particular work is proposed as a test of the expedience of using the fluorescent-antibody technique as a method for enumeration and identification of certain strains of B. cereus that have been found to be effective in preventing taste and odor in water supplies resulting from certain Actinomycete blooms.
Ultrastructural Changes of Tumor Implants in Mice
The purpose of this investigation was to observe the sequential ultrastructural changes in tumor implants of a well established tumor line in isologous mice.
Pleomorphism in Selected Genera of Algae
It is the purpose of this study to ascertain what environmental factors might cause morphological changes exhibited by certain algae, also to determine if this variation in morphology is vegetative, reproductive, or artifactual in nature, and to show what effects these changes in morpohology might have on classification of the organisms in question.
Phosphatides of Atypical Mycobacteria
The purpose of this investigation was to extract, separate, partially characterize and compare the individual phospholipids of the atypical mycobacteria.
Location of the Carotenoid Pigments of Corynebacterium Species Strain 7E1C
The purpose of this investigation was to determine the site of the carotenoid pigments in C. spp. strain 7E1C as a step towards resolving the role of the pigment in the cell.
High-Resolution Autoradiography with 33p
The purpose of this study is to provide groundwork for future autoradiographic investigations using 33P as a tracer.
Polycyclic-Aromatic-Hydrocarbon-Induced Alterations in the Physio-Chemical Characteristics of Escherechia Coli Dexyribonucleic Acid
Prior to 1965 the interactions of polycyclic aromatic hydrocarbons with DNA (Deoxyribonucleic acid) had been but moderately studied. It was concluded that, although a controversy existed, an apparent interaction occurred between DNA and certain aromatic hydrocarbon molecules and that the interaction was not an artifact of the reaction system.
Studies of the Passive Dispersal of Viable Algae and Protozoa by Aquatic and Terrestrial Beetles
The purpose of the present study was to determine the relative importance of aquatic and terrestrial beetles as possible vehicles in the passive overland dispersal of viable microorganisms.
The Immune Response of Guinea Pigs as Influenced by Hypobaric Pressure and Normoxic Environment (Part I); Membrane Filter-Fluorescent-Antibody Method for Detection and Enumeration of Bacteria in Water (Part II)
In this work experimental design and tests were established to determine whether antibody production in guinea pigs injected with a bacterial antigen is Influenced by the environment of simulated high altitude with normoxic conditions. Hematological and electrophoretic studies were simultaneously run with the antibody determinations as a check on related responses of the animals.
Selected Physiological and Biochemical Studies on Blue-Green Algae
Twenty-two different unialgal clonal isolates have been obtained at random for experimental purposes over a period of about one year. Also, during this period, at least 12 other species or strains have been isolated into unialgal cultures which had not yet been identified and/or significantly cleared of heterotrophic contaminants.
Biological Indices of Stream Pollution
A thorough biological survey and evaluation is a lengthy and expensive project. The number of technically trained persons required prevent its use by most public agencies. Since public health departments are the groups most frequently concerned with measuring the effects of pollution in streams, a need exists for a simplified method of sanitary survey. Recognizing this need, the Texas Heal Department assigned the writer the problem of devising a method of survey which would require a field party of two and could be conducted entirely from a mobile field laboratory.
Microbial Utilization of a Certain Hydrocarbon Insecticide
This problem includes, first, the isolation and identification of microorganisms which utilized the hydrocarbon insecticide as a sole source of carbon and energy; second, a determination of the effect on plants sprayed with the hydrocarbon medium as compared with the effect on plants sprayed with the hydrocarbon medium containing a good growth of hydrocarbon-utilizers; and third, a determination of the ability of laboratory stock cultures of organisms to utilize or remain alive in the hydrocarbon medium.
Morphological and Physiological Changes in Micrococcus Pyogenes Var. Aureus during Development of its Resistance to Terramycin
The problem in this investigation consists of, first, the procurement of several strains of Micrococcus pyogenes var. aureus; second, the comparison of the degree and rate of development of resistance of these organisms to terramycin; and, third, to study the morphological and physiological changes which occur during the development of resistance.
The Effect of Repeated Antigen Injections on the C' and C'4 Titers in Guinea Pig Serum
In this study the effects of repeated antigen injections on total complement (C') and C'4 of guinea pig serum were investigated to determine if constant antigenic stimulation would show changes in the C' and C'4 titers. Attempts were also made to correlate any changes with variations in antibody titers during the repeated antigen injections.