Pathogenic Microbiology Commons^™

Adaptive Evolution Of Surface Proteins In Microbial Pathogens: Lyme Disease Pathogens (Borreliella Sp.) And Human Immunodeficiency Virus Type 1 (Hiv-1), Li Li

Dissertations, Theses, and Capstone Projects

Cell and virion surface proteins are key to the survival and adaptation of microbial pathogens by enabling them to evade host immune responses and to persist in diverse environments. Pathogens respond to host immune pressures with genetic changes in surface proteins through mechanisms including point mutations, recombination, gene duplication and loss, and lateral gene transfer, resulting in novel antigenic variants and antigenic diversity. This continuous adaptation helps pathogens evade host immunity, leading to chronic infections and recurrent disease outbreaks. Understanding these mechanisms is vital for developing effective strategies to combat infectious diseases.

This dissertation comprises three chapters exploring the adaptive …

Genetic Determinants Involved In Acquisition Of Iron In The Opportunistic Pathogen Mycobacterium Abscessus, Manal F. Farhat

Dissertations, Theses, and Capstone Projects

The opportunistic pathogen Mycobacterium abscessus subsp. abscessus (Mab) has become an emerging public health threat due to the increasing number of Mab-associated chronic pulmonary disease cases. Infection cure rates are only 50% due to the complex resistance of Mab to most antimicrobial drugs and chemotherapy.

Deeper knowledge of Mab biology is needed to illuminate potential candidates for development of improved therapeutics against Mab infections. The ESX-3 type VII protein secretion system of Mab plays an important role in host inflammatory and pathological responses during infection.

In this study, we demonstrate a functional link between the ESX-3 secretion …

Elucidation Of Gene Essentiality And Genetic Determinants Of Intrinsic P-Aminosalicylic Acid Resistance In Mycobacterium Kansasii, Keith J. Levendosky

Dissertations, Theses, and Capstone Projects

Mycobacterium kansasii (Mk) is an opportunistic pathogen capable of causing tuberculosis-like pulmonary disease in immunocompromised individuals and those with other risk factors including chronic obstructive pulmonary disease or malignancy. Mk is frequently isolated from man-made water sources where it forms resilient biofilms, posing a health risk to these susceptible individuals. Despite its medical relevance as an environmental pathogen, and a close phylogenetic relationship with the obligate pathogen Mycobacterium tuberculosis (Mtb), few studies to date have probed the molecular biology and genetics of Mk. Here, we sought to apply a transposon (Tn) mutagenesis tool to dissect …

Genetic Determinants Of Carotenoid Pigmentation In The Opportunistic Pathogen Mycobacterium Kansasii, Niklas Janisch

Dissertations, Theses, and Capstone Projects

Mycobacterium kansasii (Mk) is an opportunistic pulmonary pathogen causing infections, predominantly in immunocompromised people, with symptoms similar to those caused by its close relative Mycobacterium tuberculosis (Mt). In contrast to the latter, little work has been done on Mk genetics and even less on its defining characteristic of photochromogenicity, the controlled expression of carotenoid pigments in response to light exposure.

This work represents major progress in the investigation of pigmentation-related genetic factors in Mk. We report the creation of a large-scale, random transposon-insertion mutant library of Mk and its subsequent screening for mutants with an aberration in the …

Oxydifficidin-Producing Bacillus Presents Novel Antimicrobial Activity Against Neisseria Gonorrhoeae Involving The Deda Protein, Jingbo Kan

Dissertations, Theses, and Capstone Projects

Bacterial human pathogens cause severe infectious diseases which are the second most common cause of death next to cancer and cardiovascular diseases in the world, especially in developing countries. Gonorrhea particularly, is the second most common sexually transmitted infection (STI) which is caused by the microorganism Neisseria gonorrhoeae (GC). Centers for Disease Control and Prevention (CDC) estimates that more than 1.6 million new gonorrhea cases emerged in USA in 2018 (“Detailed STD Facts - Gonorrhea” n.d.). Also, the WHO (World Health Organization) shows that gonorrhea is the most antibiotic resistant STI (“PAHO/WHO | Gonorrhea” n.d.), highlighting the shortage of efficient …

Trypanosome Lytic Factor Mediated Immunity Against Leishmania Sp., Jyoti Pant

Dissertations, Theses, and Capstone Projects

Trypanosome Lytic Factor (TLF) is an innate immunity complex that was originally discovered to protect against African Trypanosomes. The major components of TLF are Apolipoprotein A1 (APOA1), Apolipoprotein L1 (APOL1) and HPR (Haptoglobin Related Protein), where APOL1 is necessary and sufficient for trypanolysis. Recently we have shown that TLF ameliorates infections by cutaneous Leishmania species. Here we investigated the effect of different primate and human TLF against different Leishmania sp. Our result shows that TLF kills metacyclic promastigotes of cutaneous Leishmania sp. within immune cells such as neutrophils and macrophages by two different mechanism. Using transiently transfected and germline transgenic …