Life Sciences Commons^™

Regulation Of Biofilm And Antibiotic-Resistance By The Modulator Of Sara (Msa) In Staphylococcus Aureus, Antony Schwartz

Dissertations

Staphylococcus aureus is an important human pathogen that is the causative agent of life-threatening diseases such as endocarditis and osteomyelitis. The ability of S. aureus to thrive as a successful pathogen can be partially attributed to its ability to form biofilm. Biofilm is an extracellular polysaccharide, protein, and DNA-based slime layer that protects the bacterial community. The global regulator sarA is essential for biofilm formation. Since the modulator of sarA (msa) gene regulates several virulence factors and is required for the full expression of sarA, the capacity of the msa mutant to form a biofilm was examined. The mutation of …

Aging Effects On Acute Lung Inflammation After Burn Injury, Vanessa Nomellini

Dissertations

The risk of complications and death after a moderate sized burn injury is significantly higher in persons over the age of 65, while almost non-existant in young, healthy individuals. The studies outlined below use a murine model to determine the mechanisms behind the development of pulmonary complications that frequently occur in aged individuals following burn injury. We hypothesized that, since aged mice maintain an elevated proinflammatory state prior to injury, they are at an even greater risk of pulmonary inflammation than young mice given a comparable sized wound. We found that neutrophils continue to accumulate in the lungs of aged …

Ethanol Impairs Mechanisms Of Macrophage Phagocytosis And Cytokine Production, John Karavitis

Dissertations

Extensive evidence indicates that alcohol (ethanol) consumption affects human health by altering normal physiological functions of the immune system. This study investigated the effect of a single in vivo exposure of macrophages to clinically relevant levels of ethanol (1.2 and 2.2 g/kg). Following 3 hour exposure, both doses of ethanol decreased ex vivo TNFα production by splenic and alveolar macrophages (AMs). Interestingly, the higher dose of ethanol resulted in sustained suppression of LPS-induced TNFα production at 3 and 6 hours post ethanol administration, as well as decreased IL-6 and IL-12 production after 6 hours, compared control treated groups. LPS or …

Phospholipase D Signaling In T Cells, Uma Chandrasekaran

Dissertations

Antigen stimulation of T lymphocytes induces the activation of phospholipase D (PLD) signaling. Phospholipase D (PLD) is a phosphodiesterase that catalyzes the conversion of phosphatidyl choline (PC) to phosphatidic acid (PA). PA is an important lipid second messenger and is known to mediate a variety of cellular functions. However, the specific role of PA in T lymphocytes has not been established. Previous studies indicated differential requirement for TCR induced PLD signaling in regulatory and non-regulatory T cells. Inhibition of TCR induced PLD signal preferentially suppressed the growth of non-regulatory T cells while allowing the proliferation of regulatory T cells in …

B Lymphocyte Development In Galt, Venkata Arunachalam Yeramilli

Dissertations

In rabbits, the primary antibody repertoire is generated in the gut-associated lymphoid tissues (GALT), where bone marrow (BM)-derived B cells undergo a proliferative expansion and somatically diversify the immunoglobulin genes. Unlike in other species, B lymphopoiesis in rabbit arrests a few months after birth, and it is unclear how the peripheral B cell compartment is maintained when there is no influx of newly-made B cells from the BM.

For my dissertation, I investigated how B cells develop in the GALT of rabbits, and how they are maintained in adults after the arrest of lymphopoiesis. To identify cellular signals that promote …