Molecular Biology Commons^™

Transcriptional Control Of Virulence Genes In The Bacterial Pathogen Shigella Flexneri, Joy Asami Mckenna

UNLV Theses, Dissertations, Professional Papers, and Capstones

Shigella species, the causal agents of bacillary dysentery, use a type III secretion system (T3SS) to inject two waves of virulence proteins, known as effectors, into the human colonic epithelium to subvert host cell machinery. Transcriptional regulation of these virulence genes is controlled by the three-tiered VirF/VirB/MxiE signaling cascade. Of these, VirB has the largest regulon (~50 genes); however, VirB regulatory properties are poorly understood. To date, VirB is known to function to counter or 'anti-silence' transcriptional silencing mediated by the histone-like nucleoid structuring protein H-NS. To better understand VirB regulation, my colleagues and I chose to better define the …

Small Rna, Cyclic-Di-Gmp And Phenolic Compounds Regulate The Type Iii Secretion System In Bacterial Phytopathogens, Devanshi Khokhani

Theses and Dissertations

Type III Secretion System (T3SS) is an essential virulence factor in many Gram-negative bacterial pathogens. Expression of T3SS consumes large amount of energy. Hence it is tightly regulated by bacteria through several mechanisms. In this work we screened a library of phenolic compounds and found several compounds that

dramatically downregulate T3SS in Erwinia amylovora 273. Additionally, the role of small RNA (sRNA) chaperone, Hfq, and a secondary messenger, cyclic-di-GMP in T3SS regulation in Dickeya dadantii 3937 was also examined. Chapter 1 provides a brief overview of the history and virulence mechanisms of two phytopathogens - Erwinia amylovora 273 and Dickeya …