Medicine and Health Sciences Commons^™

Dna Repair Of 8-Oxo-7,8-Dihydroguanine Lesions In Porphyromonas Gingivalis, Leroy G. Henry Jr.

Loma Linda University Electronic Theses, Dissertations & Projects

The persistence of Porphyromonas gingivalis in the inflammatory environment of the periodontal pocket requires an ability to overcome oxidative stress. DNA damage is a major consequence of oxidative stress. Unlike other organisms, a non-base excision repair mechanism for the removal of 8-oxo-7,8-dihydroguanine (8-oxoG) in P. gingivalis was suggested. Because the uvrB gene is known to be important in nucleotide excision repair, the role of this gene in the repair of oxidative stress-induced DNA damage was investigated. A 3.1 kb fragment containing the uvrB gene was PCR-amplified from the chromosomal DNA of P. gingivalis W83. This gene was insertionally inactivated using …

Rit Gtpase Signaling Mediates Oxidative Stress Resistance And Survival Of Adult Newborn Neurons After Traumatic Brain Injury, Weikang Cai

Theses and Dissertations--Molecular and Cellular Biochemistry

The small GTPases function as molecular switches to control diverse signaling cascades. The mammalian Rit and Rin, along with Drosophila Ric, comprise an evolutionarily conserved subfamily of the Ras-related GTPases. Previous studies using cultured cell models suggested that Rit was involved in the control of cell proliferation, transformation, neuronal differentiation, morphogenesis, and cell survival, but the principal physiological function of Rit remained uncharacterized.

To address this outstanding question, we employed a genetic approach, engineering a Rit knockout mouse. Using this animal model, we demonstrate a central role of Rit in governing cell survival in a p38-dependent fashion. Primary mouse embryonic …

Secreted Factors From Human Umbilical Cord Blood Cells Protect Oligodendrocytes From Ischemic Insult, Derrick Rowe

USF Tampa Graduate Theses and Dissertations

Oligodendrocytes (OL)s are the dominant cell type in the white matter and are integral for synaptic transmission essential for proper neuronal communication between brain areas. Previous studies have shown that intravenous administration of the mononuclear fraction of human umbilical cord blood (HUCB) cells in rat models of stroke reduced white matter injury, gray matter injury and behavioral deficits. Yet the mechanisms used by HUCB cells remain unknown in ischemic injury. These studies will investigate both in vitro and in vivo approaches to elucidate this mechanism in OLs. When mature primary OLs were coincubated with HUCB cells, HUCB cells secreted soluble …

The Role Of Mitochondrial Oxidative Stress In Cardiovascular Disease Development, Corey Michael Harrison

All ETDs from UAB

An estimated 70 million Americans have one or more types of cardiovascular disease (CVD). Although the sequence of events leading to CVD are still controversial, there is a general consensus that atherosclerotic lesions result from oxidative stress associated with risk factor. For this study, it was hypothesized that endogenous mitochondrial oxidative stress would influence susceptibility to atherogenesis and mitochondrial damage mediated by CVD risk factor exposure. To test this hypothesis, atherosclerotic lesion formation, oxidant stress, and mitochondrial DNA damage were assessed in hypercholestoremic mice (apolipoprotein E null - apoE -/- SOD2 +/+) and mice with significantly decreased levels of the …