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Full-Text Articles in Organismal Biological Physiology
The Physiological Significance Of Nitric Oxide Synthase In Staphylococci, Ryan M. Singh
The Physiological Significance Of Nitric Oxide Synthase In Staphylococci, Ryan M. Singh
Theses & Dissertations
Staphylococci, particularly Staphylococcus epidermidis, are common causes of implant-associated infections that may result in notable morbidity and mortality. One of the ways the innate immune system attempts to combat these invading pathogens is via the respiratory burst, in which free radical species such as nitric oxide (NO•), toxic to bacterial respiration, are released in large quantities. Despite the toxicity of NO•, some bacteria, including staphylococci, encode an endogenous bacterial nitric oxide synthase (bNOS), whose physiological role has been unclear until now. In this dissertation, we demonstrate that S. epidermidis is able to overcome the toxicity …
Investigating Transcriptional Anomalies During Persistence In Chlamydia Trachomatis, Nathan D. Hatch
Investigating Transcriptional Anomalies During Persistence In Chlamydia Trachomatis, Nathan D. Hatch
Theses & Dissertations
Chlamydia trachomatis (Ctr) is the leading cause of bacterial sexually transmitted infections. Ctr, a Gram-negative, obligate intracellular bacterium, develops within a membrane-bound vacuole termed an inclusion. This protective, nutrient rich, intracellular environment has allowed Ctr to undergo extensive reductive evolution – resulting in a streamlined genome of approximately 1 Mbp and the loss or fragmentation of several biosynthetic pathways, including the ability to synthesize tryptophan (Trp) de novo. During infection, the host immune system releases the cytokine IFNγ. Upon binding to a host cell, IFNγ stimulates the expression of indoleamine-2,3-dioxygenase, an enzyme capable of catabolizing cytosolic Trp, thereby starving …
Role And Regulation Of Staphylococcal Cell Death, Abdulelah Ahmed Alqarzaee S
Role And Regulation Of Staphylococcal Cell Death, Abdulelah Ahmed Alqarzaee S
Theses & Dissertations
The transition from growth to stationary phase is a natural response of bacteria to starvation and stress. When stress is alleviated and more favorable growth conditions return, bacteria resume proliferation without a significant loss in fitness. Although specific adaptations that enhance persistence and survival of bacteria in stationary phase have been identified, mechanisms that help maintain the competitive fitness potential of non-dividing bacterial populations have remained obscure. This dissertation demonstrates that staphylococci entering stationary phase following growth in excess glucose undergo regulated cell death to maintain the competitive fitness potential of the population. Upon a decrease in extracellular pH, the …