Life Sciences Commons^™

Characterizing The Physiology And Genetics Of Contact Dependent Growth Inhibiton Systems In Burkholderia Species, Alice Elizabeth Oates

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Contact-dependent growth inhibition (CDI) systems mediate interbacterial competition. The genes encoding these systems are widespread among Gram-negative bacteria, including Burkholderia pathogens. CDI systems of Burkholderia species are composed of two-partner secretion pathway proteins and function to deliver the toxic C-terminus of a polymorphic surface-exposed exoprotein BcpA (Burkholderia CDI protein A) to the cytoplasm of neighboring recipient bacteria upon cell-cell contact. Specific outer and inner membrane proteins facilitate BcpA translocation both out of the donor bacterium and into the recipient cell cytoplasm. Most Burkholderia species-specific CDI translocation factors in recipient cells are unknown. BcpA intoxication functions as a mechanism by …

Entry And Replication Of Negative-Strand Rna Viruses, Kerri Boggs

Theses and Dissertations--Molecular and Cellular Biochemistry

Hendra virus (HeV) and human metapneumovirus (HMPV) are negative-sense, singled-stranded RNA viruses. The paramyxovirus HeV is classified as a biosafety level 4 pathogen due to its high fatality rate and the lack of a human vaccine or antiviral treatment. HMPV is a widespread pneumovirus that causes respiratory tract infections which are particularly dangerous for young children, immunocompromised individuals, and the elderly. Like HeV, no vaccines or therapies are available to combat HMPV infections. These viruses fuse their lipid envelopes with a cell to initiate infection. Blocking cell entry is a promising approach for antiviral development, and many vaccines are designed …

Substrate Trafficking Within The Type Vii Secretion Systems Of Pathogenic Mycobacteria, Zachary A. Williamson

Theses and Dissertations--Molecular and Cellular Biochemistry

Tuberculosis (TB), primarily caused by infection of Mycobacterium tuberculosis (Mtb) in the lungs, is the deadliest infectious bacterial disease killing 1.5 million people annually. A major determinant of virulence is active secretion through three specialized type VII secretion (ESX) systems; ESX-1, ESX-3, and ESX-5. A large group of substrates exported by the ESX systems is the PE (Proline-Glutamine) and PPE (Proline-Proline-Glutamate) families of proteins, which are highly expanded in the pathogenic species of Mycobacteria and encompass over 7% of Mtb’s genome coding capacity. PE and PPE proteins interact together to form PE-PPE heterodimers, and are secreted through …

Application Of Genetic Techniques To Investigate Chlamydia Trachomatis Type Iii Secretion Effector Biology, Gabrielle Keb

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Chlamydia trachomatis is the causative agent of the most reported bacterial sexually transmitted disease in the United States. The establishment of an intracellular niche within mucosal epithelium is sufficient to drive immunopathology and disease sequela. As obligate intracellular bacteria, Chlamydia spp. have evolved numerous mechanisms for establishing an intracellular growth environment. The type III secretion system (T3SS) delivers effector proteins to the host cytosol and is essential for C. trachomatis invasion and development. The effectors TmeA, TmeB, and TarP, are all secreted during C. trachomatis invasion. TarP and TmeA have been associated with manipulation of actin networks and are …

Circadian Rhythmicity And Melatonin Sensitivity In The Human Gut Commensal Bacterium Klebsiella Aerogenes, Kinga Graniczkowska

Theses and Dissertations--Biology

While the expression of circadian rhythms is nearly universal among multicellular eukaryotic organisms, demonstration of this phenomenon in prokaryotes has been largely restricted to photosynthetic cyanobacteria until very recently. Further, growing interest in gastrointestinal microbiomes has revealed a complex temporal relationship between the gastrointestinal clock and the bacterial microbiome within. At least one member of the gut microbiome, Klebsiella (née Enterobacter) aerogenes, responds to the indoleamine hormone melatonin, secreted by the gastrointestinal system itself. Further research revealed that K. aerogenes also expresses a circadian rhythm in motility and gene expression that is temperature compensated. Although rhythmicity is unaltered …

The Roles Of The Actin Network And Co-Opted Host Factors In Tbsv Replication, Melissa Gabriela Molho Medina

Theses and Dissertations--Plant Pathology

Positive-stranded (+) RNA viruses are the largest family of viruses that infect plants, causing important economic losses in different crops. Tomato bushy stunt virus (TBSV), a small positive-stranded RNA virus, has emerged as a model virus to study virus-host interactions. TBSV encodes for only five proteins, therefore, to infect the host cell TBSV co-opts selected host components and subverts specific molecular pathways.

Firstly, I performed a proteomic screening using Arabidopsis proteins. I found that TBSV viral replication proteins interact with 88 host proteins, including the ubiquitin-conjugating enzyme 2 (Ubc2), fructose 1,6 biphosphate aldolase (Fba1), and several members of the Hps70 …