Microbiology Commons^™

Genetic Analysis Of Conserved Residues In Phou Of Escherichia Coli, Stewart G. Gardner

Theses and Dissertations

The Pho regulon is controlled by the PstSCAB transporter, PhoU, and the two-component proteins, PhoB and PhoR. PhoU is a negative regulator of the Pho regulon under phosphate-replete conditions. How PhoU functions is unknown. Many PhoU homologues are found widely throughout prokaryotic domains. There are several conserved amino acid residues in the PhoU protein. It is hypothesized that these residues play an important role in the function of PhoU. To test this hypothesis, several site directed mutations in the phoU gene have been produced with single amino acid changes in conserved residues. After testing these mutants, it was found that …

Investigation Of The Mechanisms Of Ozone-Mediated Viral Inactivation, Seiga Ohmine

Theses and Dissertations

Previous studies have established that ozone-oxygen mixtures can be used to inactivate a variety of microorganisms including bacteria, fungi and viruses. Ozone is a potent reactive oxygen species (ROS) that rapidly decays into a variety of additional short half-life ROS which have been shown to cause oxidative damage to biological molecules. I hypothesize that controlled ozone exposure and the subsequent generation of additional ROS would reduce viral infectivity by lipid and/or protein peroxidation. A proprietary ozone-oxygen delivery system was used to inactivate a series of enveloped [herpes simplex virus type-1 strain McIntyre (HSV-1), vaccinia strain Elstree (VAC), vesicular stomatitis virus …

Crustacean Phylogenetic Systematics And Opsin Evolution, Megan L. Porter

Theses and Dissertations

Composed of a chromophore bound to an integral membrane protein (opsin), visual pigments are phenotypically characterized by the wavelength of maximal absorption (λmax). The underlying molecular mechanism controlling λmax is the interaction between the opsin amino acid sequence and the chromophore. While a plethora of studies have looked at structure/function relationships in vertebrate opsins, fewer studies have investigated similar issues in invertebrates. Furthermore, those few studies undertaken in invertebrate systems suggest different mechanisms of spectral tuning and photoactivation compared to vertebrate systems. This dissertation research is focused on expanding our knowledge of opsin evolution in invertebrate systems, particularly from non-insect …

Assessment Of Cell Death Parameters In Bovine Parvovirus-Infected Ebtr Cells, Lubna Salah Eldin Abdel Latif

Theses and Dissertations

Bovine parvovirus (BPV) is a helper-independent parvovirus. It has a small icosahedral capsid with a single stranded DNA genome. It is a highly stable virus with a narrow host range. It causes acute gastroenteritis in calves. It is considered to be a cytolytic virus because it kills the host cells. However, the mechanism by which the virus causes cell death is not known. The work described in this thesis assessed different parameters of cell death in BPV infected embryonic bovine tracheal (EBTr) cells. There are several ways for viruses to induce cell death. Viruses can induce apoptosis in the infected …

Identification Of Proteins Involved In Chloroplast Dna Replication, Matthew G. Lassen

Theses and Dissertations

Chapter 1

Chloroplast nucleoids (ct-nucleoids) are DNA/protein complexes involved in compacting the chloroplast genome, and may play a role in regulating DNA replication. Ct-nucleoids were isolated from young soybean plants and separated by 2-D gel electrophoresis. Gel spots were excised and analyzed by MALDI-ToF mass spectrometry, resulting in several protein identifications. The proteins identified all have functions unrelated to DNA replication. While some of these proteins may be due to contamination, it is possible that some of these proteins are dual-functional, playing direct roles in the regulation of DNA replication.

Chapter 2

A 28 kDa soybean protein was isolated by …

An Analysis Of Microbial Contamination In Military Aviation Fuel Systems, Harold W. Graef

Theses and Dissertations

Military aviation fuel systems can be an ideal environment for microorganisms. Microbial growth in hydrocarbon fuel systems arises because of the impracticality of keeping fuel tanks sterile and the inevitable presence of water from condensation. Microbial contaminants in aviation fuel systems are a concern because of their potential to degrade the fuel, accelerate tank corrosion, and threaten flight safety. This research addresses the concern of using more environmentally friendly Fuel System Icing Inhibitors (FSII), which are also biocidal. Are significant levels of microorganisms growing in military aviation fuel systems, and if so, are there any common variables? Forty aviation fuel …

Characterization Of The Surface Morphology Of Bacillus Spores By Atomic Force Microscopy, Ruth A. Zolock

Theses and Dissertations

The surface morphology of Bacillus spores was resolved by atomic force microscopy in order to determine if characteristic surface features could be used to distinguish between closely related species. Four strains were studied: Bacillus anthracis Sterne strain, Bacillus thuringiensis var. kurstaki, Bacillus cereus strain 569, and Bacillus globigii var. niger. The spores were separated from a nutrient agar culture by filtering and centrifugation, suspended in deionized water, and immobilized on a graphite substrate by spin-coating. Atomic force microscopy imaging was done using intermittent contact mode, in air, under reduced humidity. Seven to ten spores of each species were fully characterized …

Determination Of The Microbiological Load Of The Principal Meat Products Sold In The Markets Of Riobamba, Miguel Angel Castillo Palacios

Theses and Dissertations

This investigation was done with the objective to determine the microbiological load of the main meat products such as: beef, chicken meat, sausage, and viena sausage which are sold in the Riobamba city markets. This investigation was carried out in the Microbiological Laboratory Livestock Science faculty of the Polytechnical Superior school. Specific chemical products were used to determine mesofilas (37 degrees C), xicrofilas (5 degrees C), and termofilas bacteria which did not develop at 45 degrees C, however exicrofilas and mesofilas bacteria were found in every market and meat product in this study. The meat product hygiene is the same …

Heavy Metal Toxicity In Bioremediation: Microbial Cultures And Microscopy, Jason B. Goodbody

Theses and Dissertations

This research employed a variety of microscopy and spread plating techniques to observe the effects of heavy metal treatments on a toluene-selected bacterial population. Microbial colonies were cultured on spread plates and the resulting numbers were compared to respiration data. The mechanisms of reproduction were demonstrated to be more sensitive to metal treatments than were the mechanisms of respiration. Phase contrast, Gram stain, fluorescent microscopy, were used to compare and document a wide variety of bacteria resulting from different metal treatments as well as from environmental changes within the source bioreactor. The removal of sensitive bacteria and the selection of …

Determination Of The Presence Of Antibiotics And Bacterial Pathogens With Their Susceptibility In Fresh Milk From The San Nicolas Community And The Cities Of Penipe, Guano, And Chambo In The Chimborazo Province, Lupe Marín

Theses and Dissertations

This study is entitled, “determination of the presence of antibiotics and bacterial pathogens with their susceptibility in fresh milk from the San Nicolas community and the cities of Penipe, Guano, and Chambo in the Chimborazo province”. It was funded by the Benson Institute of Brigham Young University and Nestle. The objectives were: 1) to determine the presence of antibiotics in fresh milk from the San Nicolas community and the cities of Penipe, Guano, and Chambo, 2) to determine the presence of bacterial pathogens in milk from the places previously mentioned, and 3) to detect the susceptibility of the isolated bacteria …

Stem Cell Factor And Kit Expression In Type I Neurofibromatosis, Kenneth Eugene Roth

Theses and Dissertations

Neurofibromatosis type 1 (NF1) is an inherited disease characterized by the appearance of multiple neurofibromas and an increased incidence of malignant schwannomas, both of which contain hyperproliferative Schwann cells. Our laboratory previously reported that Schwann cells produce stem cell factor (SCF), a multi potential growth factor known to be involved in mast cell migration and growth. Given the fact that mast cell numbers are increased in both neurofibromas and malignant schwannomas, we set out to evaluate a potential role for SCF in the development of NF1 lesions. First we studied the effects of high doses of recombinant SCF on mast …

The Role Of Follicular Dendritic Cells In Human Immunodeficiency Virus Pathogenesis, Sonya Lynn Heath

Theses and Dissertations

Infection with Human Immunodeficiency Virus-1(HIV) results in a disease process characterized by three stages: an acute phase characterized by viremia, a clinically latent stage with little or no detection of virus in the blood, and the last stage, AIDS, which. is characterized. by marked immunodeficiency. During clinical latency, CD4+ T cells decline over a period lasting from a few to several years. Throughout this period, HIV is found trapped on the surface of follicular dendritic cells(FDC) in the germinal centers of secondary lymphoid tissues and this is the primary site of active viral replication. We hypothesize that FDC, and the …

Characterization Of Fibroblasts With A Unique Defect In Processing Antigens With Disulfide Bonds, Brian J. Merkel

Theses and Dissertations

A Chinese hamster ovary (CHO) fibroblast, transfected with murine major histocompatibility complex (MHC) class II genes, inefficiently simulated CD4+ Th cells specific for ovalbumin (OVA), hen egg lysozyme (HEL), and pork insulin which contains disulfide bonds. However, the fibroblasts elicited a T cell response to λ-repressor, which lacks disulfide bonds, and efficiently presented synthetic peptides. A somatic cell hybrid WALC, generated by fusing the hamster fibroblast with a murine L cell fibroblast, very efficiently processed OVA and HEL, suggesting that impaired processing was genetically complemented, suggesting that the processing defect is a recessive trait. Three distinct processing phenotypes were observed …

Immunomodulatory Effects Of Transforming Growth Factor-Β On T Lymphocytes, Thomas Harris Inge

Theses and Dissertations

Transforming growth factor-β1 (TGFβ) is a peptide cytokine implicated in control of growth, adhesion, and differentiation of cells in numerous tissues. TGFβ has potent inhibitory effects on many lymphocyte responses; we also found that TGFβ could inhibit in vitro generation of tumor-specific CTL. Suppression was largely reversed with exogenous IL-2. Proliferation of memory-stage CTL clones was also inhibited by TGFβ, while the upregulation of cytotoxicity was not inhibited by TGFβ. These studies suggested that TGFβ limited anti-tumor CTL responses via both an indirect effect on IL-2 production, and by a direct effect on proliferation of memory CTL.

In CTLL-2 cells, …

Mechanisms Of Complement Resistance By Pathogenic Naegleria Fowleri Amoebae, Denise Marie Toney

Theses and Dissertations

The genus Naegleria is composed of a distinct group of free-living amoeboflagellates that include both pathogenic and nonpathogenic species. N. fowleri, the only pathogenic species of Naegleria to be isolated from humans, is the etiological agent of primary amoebic meningoencephalitis, a rare but rapidly fatal disease of the central nervous system in humans and in laboratory animals. The mechanisms of pathogenicity and the determinants of virulence of N. fowleri are unknown. Both pathogenic and nonpathogenic Naegleria activate the alternative complement pathway, however pathogenic N. fowleri are complement-resistant and nonpathogenic N. gruberi are complement-sensitive. The ability to resist complement-mediated lysis …

Identification Of Regulatory Mechanisms Of Genes Encoding Citrate Synthase In The Yeast Saccharomyces Cerevisiae, Christine Smith Kell

Theses and Dissertations

The major aim of this research was to investigate the molecular mechanisms of regulation of transcription of CIT1 and CIT2, the genes encoding citrate synthase in yeast. Specifically addressed are the questions of (1) localization of cis-acting sites required for expression or regulation, (2) the roles of HAP1 and HAP2,3,4 in expression of both genes, (3) identification of other trans-acting factors involved in expression of either gene, (4) localization of cis-acting sites involved in up regulation of CIT2 in response to disruption of CIT1 or rho° status (Liao et al., 1991; Liao and Butow, 1993).

I show here that mutations …

Characterization Of A Promoter Rearrangement And A Second Promoter In The Human C-Myb Proto-Oncogene, Sarah Margaret Jacobs

Theses and Dissertations

The human cellular proto-oncogene c-myb has been implicated as important in the regulation of hematopoietic cell growth and differentiation. Aberrant expression of this gene and chromosomal aberrations near the c-myb locus have been associated with a number of carcinogenic processes. An alternatively spliced CDNA clone of c-myb, pMbm-2, contains unique 5’ sequences which replace exon 1. The existence of this 5’ divergent CDNA clone led us into a study of the promoter activity of the c-myb gene.

Intron 1 of c-myb is highly conserved between human and mouse throughout the intron, while only those sequences directly adjacent to exons …

Stem Cell Factor In Mast Cell And Schwann Cell Proliferation And Hyperplasia, John Joseph Ryan

Theses and Dissertations

Stem cell factor (SCF) is a recently characterized hematopoietic growth factor capable of stimulating the proliferation and differentiation of many hematopoietic cells, including the mast cell. We have cloned the gene encoding SCF from a cDNA library prepared from NIH 3T3 fibroblasts, and have characterized the ability of recombinant SCF to induce the development of mast cell-committed progenitors (MCCP), found in the mesenteric lymph nodes of mice infected with Nippostrongylus brasiliensis (Nb-MLN), but not naive mice. We have also examined Schwann cells, mast cells, and reproductive tissues for their ability to produce SCF.

We have found that recombinant …

Characterization Of Steroid-17,20-Desmolase And 20Α-Hydroxysteroid Dehydrogenase From Clostridium Scindens, Amy Elizabeth Krafft

Theses and Dissertations

Clostridium scindens is an obligate anaerobe isolated from the normal intestinal flora of man. It is the only bacterium known at present to synthesize both steroid-17,20-desmolase and 20α-hydroxysteroid dehydrogenase (ZOα-HSDH). This study was undertaken to characterize these neutral steroid transforming reactions in extracts of C. scindens; to purify and characterize the enzymes responsible for side-chain cleavage and 20α- hydroxysteroid oxidoreduction and to clone the genes encoding these enzymes with a view towards studying the mechanism of induction by steroids in a prokaryotic system. Both enzymes were found to be co-inducible in cells cultured in the presence of 17α-hydroxysteroids. In cell …

Proliferation And Differentiation Of Mast Cell Progenitors, Daniel Lee Jarboe

Theses and Dissertations

We have identified a late, committed stage in the differentiation of the mast cell progenitor just prior to granulation. This mast cell-committed progenitor (MCCP) differs from the more primitive bone marrow mast cell progenitor in that it is able to proliferate and differentiate in the absence of interleukin-3 (IL-3) when cultured on a monolayer of embryonic skin or 3T3 fibroblasts. The MCCP can be harvested from the mesenteric lymph nodes of mice in their fourteenth day of infection with the rodent hookworm Nippostrongylus brasiliensis and can be cloned in a methylcellulose culture system by supplementing the cultures with fibroblast-conditioned medium …

Phenotypic And Functional Characterization Of Ia+ And La- Sublines Of The Human Monocyte-Like Cell Line, U937, Coles Meredith Squire

Theses and Dissertations

Sublines were derived from the U937 human monocytic cell line by limiting dilution techniques. Several of the sublines derived in this manner were found to constituitively express la, unlike most U937 cell lines previously examined. Thus the la+ and la- sublines were examined and characterized phenotypically and functionally. Morphologically the sublines, both la+ and la-, were found to be similar to the originally described U937 parent cell line. They were positive for production of non- specific esterase and expressed the HLA phenotype A(3,X), B(51,18), DR(2,X). The sublines were examined by immunofluorescence techniques with a large number of antibodies specific for …

Characterization Of A Staphylococcal Trimethoprim Resistance Gene, Jerald Preston Coughter

Theses and Dissertations

Trimethoprim resistance(Tp r) is encoded by conjugative plasmids in clinically significant staphylococcal isolates. Two genetically and physically similar plasmids from S. aureus, pG01 and pGOS, have Tp r genes that map in different locations on these plasmids. In order to study the relatedness of the Tp r genes and their products to other known Tp r genes, a 1.2 kb fragment of pG01 and a 4.2 kb fragment of pGOS were cloned in E. coli and used as probes for in situ filter hybridization experiments.

A 500 base pair subclone of the original 1.2 kb fragment containing only the staphylococcal …

Degradation Of Human Anaphylatoxin C3a By Rat Peritoneal Mast Cells: A Role For The Secretory Granule Enzyme Chymase And Heparin Proteoglycan, James Edmund Gervasoni Jr

Theses and Dissertations

Purified human C3a was iodinated (¹²⁵I-C3a) and used to study the interaction of labeled peptide with rat peritoneal mast cells (RMC). Cellular binding of ¹²⁵I-C3a occurred within 30 sec, followed by a rapid dissociation from the cell. Both the binding of ¹²⁵I-C3a and the rate of dissociation from the cell were temperature dependent. At 0°C, the binding of ¹²⁵I-C3a was increased and the rate of dissociation reduced, as compared to 37°C. Once ¹²⁵I-C3a was exposed to RMC, it lost the ability to rebind to a second batch of RMC. Analysis of the supernatants by …

Dissection Of Microphage Activation Using T Cell Hybridoma Derived Lymphokines, William S. Futch Jr.

Theses and Dissertations

Macrophage phenotype/function can be modulated by various T-cell lymphokines (LK). The alteration of macrophage phenotype is a result of LK concentration, duration of exposure, and the level of macrophage activation when obtained from in vivo sources through elicitation by either sterile irritants or immune cellular mechanisms. In order to dissect macrophage activation into discrete signals T cell hybridomas were constructed by fusing HAT sensitive BW5147 cells with nylon-wool purified, con A stimulated T cells. The resulting T cell hybrids were screened for their ability to: (a) protect macrophages from the cytopathic effect of Naegleria; (b) induce class II MHC gene …

Enflagellation Of Naegleria Fowleri, Terry Wayne Woodworth

Theses and Dissertations

Organisms of the genus Naegleria differentiate from feeding, dividing amebae into temporary swimming flagellates when deprived of nutrients. Factors critical for enflagellation of the pathogenic species, N. fowleri, were delineated and optimal conditions established for evoking reproducible conversion of N.fowleri populations. N. fowleri enflagellation differed from that of N. gruberi in its dependence upon growth phase, population density during enflagellation and in the timing and extent of the conversion. N. fowleri amebae from stationary phase cultures grown at 37°C, washed free of medium and suspended in nutrient~free ameba saline, acquired flagella and converted to mature flagellates in a synchronous manner …

Solubilization And Partial Characterization Of An Activity Regulating Complement Activation From Membranes Of Raji And Tonsil Cells, Patricia L. Carlson

Theses and Dissertations

Complement is one of the major innate nonspecific mechanisms for host defense in serum. More than a dozen proteins have been isolated from serum which have a function in either the activation or regulation of complement action. Complement is similar to the coagulation sequence in that it comprises a number of precursor proenzymes in plasma that are sequentially cleaved to generate biologically and enzymatically active proteins.

The Role Of Retained Antigen As An Etiological Agent In Rheumatoid Arthritis, Patricia Liccardi Rice

Theses and Dissertations

The cause(s) of arthritis and many other connective tissue diseases are largely unknown. An infectious agent, either bacterial or viral, has not been unequivocally isolated. Theories on the pathogenesis of arthritis abound. Many of these theories implicate the immune system as the problem.

The early information on animal arthridites implicates retained bacterial cell wall antigens as the basis of the arthritis seen. How-ever, numerous types of antigens, both complex polymers and simple proteins, have been shown to persist in immune animals. The antigens persist in the lymph nodes and spleens playing a role in mediating antibody feedback mechanisms. Antigens also …

Efficacy Of Salinomycin On Infections Of Plasmodium Berghei In Male Icr Mice, Anthony Stephen Tokarz

Theses and Dissertations

The objective of this study was to determine whether or not salinomycin, a drug with proven effectiveness against intestinal sporozoan parasites, has any effect on the survival time of mice infected with P. berghei.

Antiviral Activity Of Peritoneal Exudate Cells Of Mice Against Infection With Herpes Simplex Virus Type 2, Margaret Byrd Mcgeorge

Theses and Dissertations

Within the past decade, there has been increasing evidence which suggests that herpes simplex virus type two (HSV-2) is associated with cervical carcinoma. Because cancer of the cervix ranks as the second most common malignant disease of women, with 35 thousand new cases and 10,000 deaths per year, further investigation is warranted to determine if there is a causal relationship (Goldberg, 1976). Currently, most of the evidence which correlates HSV-2 with cancer of the cervix has been, for the most part, indirect: (i) there is an increased incidence of cervical anaplasia in women with cytologically detectable genital herpes infection, (ii) …

Oncogenic Transformation By Herpes Simplex Virus, James Christian Burns

Theses and Dissertations

Many lines of evidence exist associating herpes simplex virus (HSV) with the development of carcinoma. Data from human studies includes seroepidemiologic studies of carcinoma patients and the localization of viral markers in human cancers. Experimental studies include in vitro transformation of cultured cells and viral induced alterations of host DNA. Much of this evidence is anecdotal or associative in nature and does not prove a cause and effect. The purpose of this research was to investigate the oncogenic potential of HSV type 2 (HSV-2) in vivo and in vitro.

An in vivo mouse model for lib carcinogenesis was designed to …