Microbiology Commons^™

Development Of A Model For Infective Endocarditis Via Intravenous Injection And Tooth Infection Of Rats Using Pathogenic Bacteria, Shahrokh Shabahang

Loma Linda University Electronic Theses, Dissertations & Projects

Historically, focal areas of infection have been linked to a number of systemic ailments. During the early part of the 20th century, patients who were suffering from inexplicable diseases and who were suspected of having infected teeth were referred to the dentist for multiple extraction of their dentition. The discovery of antibiotics provided a false sense of security that the war against microorganisms is no longer a concern for mankind. However, more recently, it has become common belief that increasing numbers of systemic diseases are linked to chronic infections. Recovery of bacteria from representative tissues has led investigators to believe …

Genomic Diversity In Staphylococcus Aureus, Bret Max Barton

Loma Linda University Electronic Theses, Dissertations & Projects

Staphylococcus aureus chromosomal DNA from 125 methicillin-resistant and 10 methicillin-sensitive clinical isolates was digested with rare-cutting restriction endonucleases and subjected to pulsed-field gel electrophoresis (PFGE). Thirty-nine distinct genomic macrorestriction patterns (GPs) were identified using SmaI; 29 of these patterns are from methicillin-resistant S. aureus (MRSA).

A dendrogram showing percent similarity among the patterns was constructed which revealed the considerable genomic diversity of the collection even though the isolates had been obtained during outbreaks. The majority of the MRSA formed one broad group with two outbreak subclasses. However, 8 of the 29 MRSA GPs (28%) were diverse.

Digestion with Csp …

Cellular Responses In Escherichia Coli To Lethal And Sublethal Doses Of Ozone, Indira Ruth Komanapalli

Loma Linda University Electronic Theses, Dissertations & Projects

Ozone is a major component of photochemical smog. High levels of this pollutant, sufficient to affect human health are found in many urban areas worldwide. Though limited studies in humans are supported by extensive findings from animal experiments, a difficulty in interpreting the results of these experiments has lead to an ambiguity on the biochemical mechanism of ozone toxicity. To elucidate the mechanism by which ozone causes cell damage and eventual cell death we conducted a comprehensive study using Escherichia coli K-12 as a model.

Studies on the comparative inactivation of bacteriophage lambda (λ), Escherichia coli, and Candida albicans …

Thymic Peptide Modulates Glutathione Redox Cycle And Antioxidant Enzymes In Macrophages, Choon Sil Park

Loma Linda University Electronic Theses, Dissertations & Projects

The effect of a 6-kDa thymic peptide (TP) on the oxidative burst of a murine macrophage cell line J774 was determined. TP (12.5-200 μg/ml) was incubated with 5 x 10⁵ J774 cells at 37° C and 5% C0₂ for 18 h and oxidative burst was triggered by zymosan; chemiluminescence was amplified by luminol and measured in an automated luminometer. TP exhibited a concentration-dependent inhibition of oxidative burst. To study the mechanisms involved in TP’s inhibition of oxidative burst, its effect on the glutathione (GSH) redox cycle, GSH biosynthesis, and antioxidant enzymes was investigated. TP was shown to increase …

Characterization Of Hsd::Mudx128 Operon Fusion Mutant Of Escherichia Coli K-12, Marjorie Ann T. Reyno

Loma Linda University Electronic Theses, Dissertations & Projects

The study of the regulation of gene expression in complex genes can be facilitated by the use of operon fusions which place a well characterized lacZ gene under the control of a promoter of interest. An hsd::MudX128 operon fusion mutant of E. coli K-12 isolated by Prakash (1986) was observed to have a high β-galactosidase activity (1000 units), ten to twenty times higher than other hsd::MudX mutants. This β-galactosidase activity was suppressed to a very low level (25 units) by the introduction of an F’ plasmid, F'101, which carries the 98 min to 2 min region of the …

Enhancement Of Intratumor Antibody Distribution With A Bifunctional Antibody Delivery System And With Hyperthermia, Karen Lynn King

Loma Linda University Electronic Theses, Dissertations & Projects

The intratumor distribution of a new monoclonal antibody-hapten-based delivery system was examined. From two marine antibodies, Hybritech, Inc. has developed a bifunctional antibody (BPA) with specificities against CEA (ZCE-025 or GEM 231) and against one of two derivatives of [¹¹¹In]-benzyl-EDTA (CHA 255), EOTUBE or BLEDTA IV, to form ZCE/CHA or CEM/CHA. BFA accumulates in CEA-expressing tissue and clears from non-antigenic tissues prior to administration of an [¹¹¹In]-hapten.

Using five groups of nude mice bearing human colon tumor xenografts (T380), we evaluated different carriers of [¹¹¹In]-EOTUBE to prelocalized ZCE/CHA. We administered all antibodies and haptens …

Selenium-Induced Enhancement Of Hematoporphyrin Derivative Phototoxicity In Murine Bladder Tumor Cells, Jeffrey M. Tosk

Loma Linda University Electronic Theses, Dissertations & Projects

The phototoxicity of hematoporphyrin derivative (Hpd) to murine bladder tumor (MBT-2) cells was studied in vitro. It was observed that selenium in the form of sodium selenite enhanced Hpd-sensitized photodamage in MBT-2 cells under conditions where the selenite alone was non-toxic. Sodium selenite was found to enhance the fluorescence emission of Hpd and augment the Hpd-sensitized photooxidation of tryptophan. The data indicate that sodium selenite is able to disaggregate Hpd, thereby enhancing Hpd-sensitized phototoxicity.

Mast Cell Histamine Release Induced By Portuguese Man-Of-War (Physalia) Venom, A. Lester Flowers

Loma Linda University Electronic Theses, Dissertations & Projects

Richet and Portier studied the immunization of dogs against attenuated toxic extracts of the sea anemone and showed that, when given secondary injections of sublethal amounts of native toxic extracts, the dogs experienced severe pruritus and insensitivity followed by death. They called this increased sensitivity to the toxins, anaphylaxis. Richet and Portier, and later Jacques and Schachter, and Uvnäs also studied the direct pruritic and histamine releasing effects of cnidarian (e.g. Physalia, Actinia, Cyanea), toxic extracts. While the anaphylactic effect, discovered by Richet and Portier, has been extended by numerous studies to provide the foundation of our current knowledge of …

Effect Of Time And Diet On The Immune Status Of Mice Challenged With Herpes-Transformed Cells, Daila S. Gridley

Loma Linda University Electronic Theses, Dissertations & Projects

Human Herpes simplex virus type 2 (HSV 2)-transformed Balb/c mouse cells (H238 cells) are malignant in Balb/c mice. The immune stratus of mice bearing H238 cell-induced tumors was studied and changes in immune response with time and with altered diet of the mice were measured.

In the experiments dealing with the status of immunity with time after tumor cell injection, mice were fed Purina Laboratory Chow (P.L.C.), injected with H238 cells, and sacrificed three to eight weeks post-injection. In the diet experiments, groups of mice were fed either P.L.C. or one of six equicaloric diets, consisting of low or high …

The Effect Of Infection With Polyoma Virus On The Protein, Rna, And Dna Of Mouse Embryo Cell Cultures, Lawrence E. Mcconnehey

Loma Linda University Electronic Theses, Dissertations & Projects

In four separate experiments mouse embryo cell monolayers infected with polyoma virus and uninfected control mouse embryo cells were maintained in Eagle’s Minimum Essential Medium for periods of time ranging from 0 to 168 hours. The cell layers were removed from the glass by trypsinization. Samples of the cells were counted in a Coulter Counter and the remainder of the cells frozen after centrifugation, in a button. Later, the buttons were thawed and protein, RNA, and DNA analyses were performed on each sample. The micrograms per million cells of protein. RNA, and DNA were determined for each sample and plotted …