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Articles 151 - 180 of 689

Full-Text Articles in Pathogenic Microbiology

Detecting Bacterial Species From Ancient Human Skeletal Samples, Ariel Owens, Daisy Mcgrath, Tsai-Tien Tseng May 2021

Detecting Bacterial Species From Ancient Human Skeletal Samples, Ariel Owens, Daisy Mcgrath, Tsai-Tien Tseng

Symposium of Student Scholars

This paleopathological study aims to identify Mycobacterium tuberculosis complex (MTBC), Mycobacterium avium complex (MAC) and other Mycobacterium species in silico from skeletal samples that belonged to 28 Polish individuals in the Neolithic period under PRJNA422903 from the Sequence Read Archive (SRA). After next-generation sequencing (NGS), bioinformatics methods are heavily relied upon for identification of pathogens from complex samples. We implemented a bioinformatics pipeline, with custom-built databases, utilizing the following software tools: Trim Galore! and Kraken2. After adapter trimming, Kraken2 was used for taxonomic classifications. We have found that Mycobacterium is present in all 28 individuals. The average percentage of MAC …

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Role And Regulation Of Staphylococcal Cell Death, Abdulelah Ahmed Alqarzaee S May 2021

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 …

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Profile Of Antimicrobial Susceptibility From Cattles’S Milk Isolates Suffering From Mastitis In District Lahore, Muhammad Imran, Iqra Rehman, Abdul Qayyum Khan Sulehria, Yasser Mustafa Butt, Abdul Majid Khan, Azizah Ziauddin May 2021

Profile Of Antimicrobial Susceptibility From Cattles’S Milk Isolates Suffering From Mastitis In District Lahore, Muhammad Imran, Iqra Rehman, Abdul Qayyum Khan Sulehria, Yasser Mustafa Butt, Abdul Majid Khan, Azizah Ziauddin

Journal of Bioresource Management

Mastitis is highly prevalent infection in cattle causing cost-effective loss in dairy milk production. Escherichia coli is the most frequently isolated bacteria causing mastitis worldwide. The current study was performed to investigate the mastitis prevalence and effect of different antibiotics against pathogens causing it. In sum, 216 milk samples were collected randomly including 108 each from both cows and buffaloes. These samples were subjected to Surf Field Mastitis Test for prevalence of mastitis that found 18.50% and 23.14% in buffaloes and cows respectively. Mastitis was more prevalent both in buffaloes and cows at the age of 9-10 years that was …

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Sickness Behaviors Across Vertebrate Taxa: Proximate And Ultimate Mechanisms, Patricia C. Lopes, Susannah S. French, Douglas C. Woodhams, Sandra A. Binning May 2021

Sickness Behaviors Across Vertebrate Taxa: Proximate And Ultimate Mechanisms, Patricia C. Lopes, Susannah S. French, Douglas C. Woodhams, Sandra A. Binning

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

There is nothing like a pandemic to get the world thinking about how infectious diseases affect individual behavior. In this respect, sick animals can behave in ways that are dramatically different from healthy animals: altered social interactions and changes to patterns of eating and drinking are all hallmarks of sickness. As a result, behavioral changes associated with inflammatory responses (i.e. sickness behaviors) have important implications for disease spread by affecting contacts with others and with common resources, including water and/or sleeping sites. In this Review, we summarize the behavioral modifications, including changes to thermoregulatory behaviors, known to occur in vertebrates …

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Diagnostic Approaches To Combat Antibiotic Resistance In Bacteria, Alexander Oliveri, Shade Smith, Anshul Anugu May 2021

Diagnostic Approaches To Combat Antibiotic Resistance In Bacteria, Alexander Oliveri, Shade Smith, Anshul Anugu

Honors Theses

The threat of antibiotic resistance is a major problem faced by the healthcare field affecting millions of people and costing tens of thousands of lives annually. Of the potential ways to mitigate this issue the field of antibiotic resistance testing presents an opportunity for significant improvement and benefits. Several methods of such diagnostic processes can yield more informative results than the current commonly used Kirby-Bauer test. However, there are benefits and limitations to each method. In the context of a clinically relevant diagnostic for antibiotic resistance, the microarray platform exhibits the necessary breadth with opportunities to overcome some limitations with …

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Interregulation Between Msaabcr Operon And Ccpe To Determine Staphylococcal Metabolism And Virulence, Erin R. Cox May 2021

Interregulation Between Msaabcr Operon And Ccpe To Determine Staphylococcal Metabolism And Virulence, Erin R. Cox

Honors Theses

Staphylococcus aureus is a complex human pathogen that causes problems in both healthcare and community settings. Staphylococcus aureus is a gram-positive, sphere shaped bacterium that usually colonizes in the nasal cavity of healthy individuals. Staphylococcus aureus infections are a growing health concern due to its ability to produce virulence factors, such as pigmentation, protease production, and capsule formation. Two regulators in S. aureus virulence factors are msaABCR, which is a newly characterized operon, and ccpE. In order to determine the interaction between these two regulators in regulating virulence and metabolism in S. aureus, ccpE and ccpE/ …

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Study Of The Role Of The Msaabcr Operon In Tricarboxylic Acid Cycle Activity And Persister Cell Formation In Staphylococcus Aureus, Karsen Motter May 2021

Study Of The Role Of The Msaabcr Operon In Tricarboxylic Acid Cycle Activity And Persister Cell Formation In Staphylococcus Aureus, Karsen Motter

Honors Theses

Staphylococcus aureus is an important human pathogen that causes wide arrays of infections ranging from minor skin infections to lethal systemic conditions such as infective endocarditis, osteomyelitis, sepsis and pneumonia. These systemic diseases are often difficult to treat due to the presence of persister cells. Persister cells are a phenotypic variant of the bacterial population that exhibit extreme and transient antibiotic tolerance accompanied by a transient halt in growth. Upon cessation of antibiotic treatment, however, persisters resume growth which results in recurrence of infections. This characteristic of persister cells therefore displays high clinical significance. In this study, we show the …

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Phenotypic Characterizations Of Msaabcr Operon Deletion In Staphylococcus Epidermidis Rp62a, Raelyn Williams May 2021

Phenotypic Characterizations Of Msaabcr Operon Deletion In Staphylococcus Epidermidis Rp62a, Raelyn Williams

Honors Theses

Staphylococcus epidermidis is a human pathogen that is increasingly known for its role in hospital infections associated with implantable medical devices. Antibiotic resistance has become a concerning issue for these infections as this bacteria have various virulence traits that help to evade immune response and antibiotic treatment. Currently, the most effective way to treat S. epidermidis infection is removal of the implant and long-term antibiotic treatment. S. epidermidis causes infection by expressing several protein factors that induce biofilm formation, the bacteria’s primary virulence mechanism. The purpose of this study was to perform the phenotypic characterizations of the msaABCR operon in …

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The Impact Of Oxygen Availability And Oxidative Stress On Regulation Of Cyclic-Dimeric-Gmp In Listeria Monocytogenes Strain F2365, Anna G. Welch May 2021

The Impact Of Oxygen Availability And Oxidative Stress On Regulation Of Cyclic-Dimeric-Gmp In Listeria Monocytogenes Strain F2365, Anna G. Welch

Honors Theses

Listeria monocytogenes is a gram-positive foodborne pathogen that results in the infectious disease listeriosis. The second messenger molecule cyclic-dimeric-GMP has been found to be responsible for the regulation of expression of many of its virulence factors with diguanylate cyclases and phosphodiesterases regulating the intracellular concentration of cyclic-di-GMP through synthesis and degradation, respectively. This study investigated the possibility that the availability of oxygen is the environmental signal crucial to the regulation of these enzymes. Prior research in our laboratory has demonstrated that the intracellular concentration of cyclic-di-GMP is elevated when exposed to anaerobic conditions. Due to this, it was hypothesized that …

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Pathogenicity Of Staphylococcus Agnetis Associated With Lame Broilers With Osteomyelitis, Sura Faris Salih Zaki May 2021

Pathogenicity Of Staphylococcus Agnetis Associated With Lame Broilers With Osteomyelitis, Sura Faris Salih Zaki

Graduate Theses and Dissertations

We developed High Resolution Melt Analysis (HERMA) as a rapid and reliable molecular diagnostic assay for the detection and identification of the main bacterial species recovered from the blood and lesions of bacterial chondronecrosis with osteomyelitis (BCO) from the lame broilers at the University of Arkansas poultry research farm. Also, the present study confirms that raising young birds on suspended wire flooring has been proved to successfully induce lameness attributable to BCO with birds being more susceptible to bacteraemia than those that were raised on litter flooring. The newly described pathogen, Staphylococcus agnetis, has been reported to be overrepresented in …

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Developing A Microdialysis Sampling-Based Biofilm/Macrophage Co-Culture Model, Alda Diaz Perez May 2021

Developing A Microdialysis Sampling-Based Biofilm/Macrophage Co-Culture Model, Alda Diaz Perez

Graduate Theses and Dissertations

The host immune system and bacterial cells are known to interact during the human lifetime. Bacteria secrete a wide variety of signaling molecules, known as quorum sensing (QSC) molecules, that modulate the host immune system. While immune-biofilm interactions involve this chemical signaling network, the mechanisms through which this occurs are not well understood. This work aimed to develop a new method that can be used not only in vitro settings but also in vivo. The microdialysis sampling technique has widely been used in in vitro and in vivo settings in humans, mice, and rats for the collection of neuropeptides, cytokines, …

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A Metabolomics-Based Approach To The Screening Of Endometrial Cancer: Development Of A Gas Chromatography-Ion Trap Mass Spectrometry-Based Method, Allycia Lee May 2021

A Metabolomics-Based Approach To The Screening Of Endometrial Cancer: Development Of A Gas Chromatography-Ion Trap Mass Spectrometry-Based Method, Allycia Lee

Honors Theses

Endometrial Cancer (EC) is the most common malignant tumor of the female reproductive tract. Currently there are no methods for effectively screening EC, but one method that is thought to be useful in screening EC is metabolomics. Metabolomics involves the analysis of metabolites which are low molecular weight inorganic and organic chemicals that are substrates, intermediates, and by-products of enzyme-mediated biochemical reactions in the cell. Previous research shows that the metabolic signature of EC patients are discernable from those of healthy patients. To aid in the development of an effective screening method for EC, blood serum, urine, and saliva samples …

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Sodium Pyruvate Ameliorates Influenza A Virus Infection In Vitro And In Vivo, Jessica M. Reel May 2021

Sodium Pyruvate Ameliorates Influenza A Virus Infection In Vitro And In Vivo, Jessica M. Reel

MSU Graduate Theses

Pyruvate is produced in duplicate at the end of glycolysis in addition to ATP and NADH. Pyruvate is the metabolite of choice in most cells, whether obtained exogenously or endogenously. Recently we found that the addition of pyruvate’s conjugate base, sodium pyruvate, to cell culture media dampened the immune response to influenza A virus (IAV) infection in cultured innate immune cells. Thus, I decided to investigate the mechanism and potential for treatment of IAV. In vitro using bone marrow derived macrophages that were infected with IAV we found that adding sodium pyruvate to the media decreased immune signaling pathways through …

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Antibiotic Resistance, A Global Pandemic, Deneil Patel May 2021

Antibiotic Resistance, A Global Pandemic, Deneil Patel

Chancellor’s Honors Program Projects

No abstract provided.

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Vignette 14: Eelgrass Wasting Disease, Olivia Graham, Morgan Eisenlord, Drew Harvell May 2021

Vignette 14: Eelgrass Wasting Disease, Olivia Graham, Morgan Eisenlord, Drew Harvell

Institute Publications

Rising seawater temperatures can increase the risk of disease outbreaks in many taxa. Pathogens are potentially the ultimate keystone species in that their small biomass can have massive impacts that ripple through ecosystems. Disease outbreaks can be particularly damaging when they affect ecosystem engineers, such as seagrasses. Outbreaks of wasting disease in seagrasses are one of a myriad of stressors associated with declining temperate and tropical seagrass meadows around the globe. Levels of eelgrass wasting disease are high in the San Juan Islands and Puget Sound. These increasing levels of disease are a threat to sustainability of eelgrass meadows, our …

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Increasing The Frequency Of Periodic Spatial Disturbance Decreases Surface Attachment Protein Expression In Staphylococcus Aureus, Ivana M. Barraza Apr 2021

Increasing The Frequency Of Periodic Spatial Disturbance Decreases Surface Attachment Protein Expression In Staphylococcus Aureus, Ivana M. Barraza

All HCAS Student Capstones, Theses, and Dissertations

Staphylococcus aureus is an opportunistic pathogen that can cause a variety of acute and chronic illnesses. The severity of these illnesses such as sepsis, necrotizing pneumonia, and toxic shock syndrome is measured through the virulence that S. aureus inflicts on its host. Methicillin-resistant S. aureus (MRSA) is commonly associated with secondary infections and is challenging to treat given the limited selection of antibiotics that are effective against it. Accordingly, novel approaches to reduce S. aureus pathogenicity are required. S. aureus regulates pathogenesis through a cell-to-cell communication system referred to as quorum sensing. Effective communication determines the production of two broad …

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Process Interventions For Improving The Microbiological Safety Of Low Moisture Food Ingredients, Tushar Verma Apr 2021

Process Interventions For Improving The Microbiological Safety Of Low Moisture Food Ingredients, Tushar Verma

Department of Food Science and Technology: Dissertations, Theses, and Student Research

The recurrence of Salmonella in low moisture foods and the implementation of the FSMA rule requires a need to validate legacy and novel processing technologies. In this dissertation, a legacy thermal (extrusion), a novel thermal (radiofrequency (RF) heating), and a non-thermal (chlorine dioxide) technology, were evaluated as intervention technologies for Salmonella in low moisture foods. The twin-screw extruder was performed at different levels of screw speeds, temperatures, moisture contents, and fat contents to understand the impact of processing conditions on Salmonella inactivation in oat flour. At temperature >65°C, the Salmonella population was below the detection limit. At 55°C, Salmonella reduction …

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Respiratory Pathogens In Patients With Acute Exacerbation Of Non-Cystic Fibrosis Bronchiectasis From A Developing Country, Shayan Shahid, Kausar Jabeen, Nousheen Iqbal, Joveria Farooqi, Muhammad Irfan Apr 2021

Respiratory Pathogens In Patients With Acute Exacerbation Of Non-Cystic Fibrosis Bronchiectasis From A Developing Country, Shayan Shahid, Kausar Jabeen, Nousheen Iqbal, Joveria Farooqi, Muhammad Irfan

Medical College Documents

Bronchiectasis unrelated to cystic fibrosis (non-CF bronchiectasis) has become a major respiratory disease in developing nations. The dilated mucus filled airways promote bacterial overgrowth followed by chronic infection, bronchial inflammation, lung injury and re-infection Accurate pathogen identification and antimicrobial susceptibility allowing appropriate treatment, in turn, may break this vicious cycle. To study the spectrum and antimicrobial spectrum of pathogen yielded from respiratory specimens in adult patients with acute exacerbation of non-cystic fibrosis (CF) bronchiectasis. This cross-sectional study was performed at the pulmonology clinics of the Aga Khan University, Karachi, Pakistan from 2016-2019. Respiratory specimens were collected from adult patients with …

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Molecular Surveillance Of Drug Resistance: Plasmodium Falciparum Artemisinin Resistance Single Nucleotide Polymorphisms In Kelch Protein Propeller (K13) Domain From Southern Pakistan, Najia Karim Ghanchi, Bushra Qurashi, Hadiqa Raees, Mohammad Asim Beg Apr 2021

Molecular Surveillance Of Drug Resistance: Plasmodium Falciparum Artemisinin Resistance Single Nucleotide Polymorphisms In Kelch Protein Propeller (K13) Domain From Southern Pakistan, Najia Karim Ghanchi, Bushra Qurashi, Hadiqa Raees, Mohammad Asim Beg

Department of Pathology and Laboratory Medicine

Background: K13 propeller (k13) polymorphism are useful molecular markers for tracking the emergence and spread of artemisinin resistance in Plasmodium falciparum. Polymorphisms are reported from Cambodia with rapid invasion of the population and almost near fixation in south East Asia. The study describes single nucleotide polymorphisms in Kelch protein propeller domain of P. falciparum associated with artemisinin resistance from Southern Pakistan.
Methods: Two hundred and forty-nine samples were collected from patients with microscopy confirmed P. falciparum malaria attending Aga Khan University Hospital during September 2015-April 2018. DNA was isolated using the whole blood protocol for the QIAmp DNA Blood Kit. …

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Effectiveness Of Pathogen-Specific Passive Antibodies To Mitigate Infectious Diseases In Apis Mellifera, Tanner Nordseth Apr 2021

Effectiveness Of Pathogen-Specific Passive Antibodies To Mitigate Infectious Diseases In Apis Mellifera, Tanner Nordseth

Honors Thesis

Honeybees (Apis mellifera) are widely recognized as a vital part of the global ecosystem and the world's food supply due to their pivotal role in the pollination of both natural and agricultural flora. Colony Collapse Disorder (CCD) is an emerging phenomenon characterized by a colony's worker bees deserting the hive and leaving the queen behind. This usually results in colony failure. CCD is a multifactorial issue, with many environmental stressors and pathogens playing a role. Deformed Wing Virus (DWV) has been identified as a leading cause in this phenomenon. Paenibacillus larvae (P. larvae) is another lethal pathogen that is …

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Cloning Of Pe11 (Lipx, Rv1169c) Gene Of Mycobacterium Tuberculosis Beijing Strain To Pcdna3.1 Plasmid Vector, Lulut Azmi Supardi, Andriansjah Rukmana, Fithriyah Sjatha Mar 2021

Cloning Of Pe11 (Lipx, Rv1169c) Gene Of Mycobacterium Tuberculosis Beijing Strain To Pcdna3.1 Plasmid Vector, Lulut Azmi Supardi, Andriansjah Rukmana, Fithriyah Sjatha

Makara Journal of Science

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis. It is a persistent global health problem with a high mortality rate. Currently, TB is controlled by administering the Bacillus Calmette-Guerin (BCG) vaccine, but the effectiveness of its protection varies among individuals in a population. The pe/ppe gene family comprises a typical group of genes that play a role in avoiding the host immune response and inducing persistent TB infection. Based on in silico analysis, the pe11 gene has estimated immunogenicity and potential as a TB seed vaccine candidate. The pe11 gene from an Indonesian isolate of an M. …

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Pirnas As Modulators Of Disease Pathogenesis, Kayla J. Rayford, Ayorinde Cooley, Jelonia T. Rumph, Ashutosh Arun, Girish Rachakonda, Fernando Villalta, Maria F. Lima, Siddharth Pratap, Smita Misra, Pius N. Nde Feb 2021

Pirnas As Modulators Of Disease Pathogenesis, Kayla J. Rayford, Ayorinde Cooley, Jelonia T. Rumph, Ashutosh Arun, Girish Rachakonda, Fernando Villalta, Maria F. Lima, Siddharth Pratap, Smita Misra, Pius N. Nde

Publications and Research

Advances in understanding disease pathogenesis correlates to modifications in gene expression within different tissues and organ systems. In depth knowledge about the dysregulation of gene expression profiles is fundamental to fully uncover mechanisms in disease development and changes in host homeostasis. The body of knowledge surrounding mammalian regulatory elements, specifically regulators of chromatin structure, transcriptional and translational activation, has considerably surged within the past decade. A set of key regulators whose function still needs to be fully elucidated are small non-coding RNAs (sncRNAs). Due to their broad range of unfolding functions in the regulation of gene expression during transcription and …

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When The Pandemic Opts For The Lockdown: Secretion System Evolution In The Cholera Bacterium, Francis J. Santoriello, Stefan Pukatzki Feb 2021

When The Pandemic Opts For The Lockdown: Secretion System Evolution In The Cholera Bacterium, Francis J. Santoriello, Stefan Pukatzki

Publications and Research

Vibrio cholerae, the causative agent of the diarrheal disease cholera, is a microbe capable of inhabiting two different ecosystems: chitinous surfaces in brackish, estuarine waters and the epithelial lining of the human gastrointestinal tract. V. cholerae defends against competitive microorganisms with a contact-dependent, contractile killing machine called the type VI secretion system (T6SS) in each of these niches. The T6SS resembles an inverted T4 bacteriophage tail and is used to deliver toxic effector proteins into neighboring cells. Pandemic strains of V. cholerae encode a unique set of T6SS effector proteins, which may play a role in pathogenesis or pandemic …

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Characterizing The Physiology And Genetics Of Contact Dependent Growth Inhibiton Systems In Burkholderia Species, Alice Elizabeth Oates Jan 2021

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 …

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Application Of Genetic Techniques To Investigate Chlamydia Trachomatis Type Iii Secretion Effector Biology, Gabrielle Keb Jan 2021

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 …

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Targeting Transferrin Binding Protein A For Vaccine Development In Neisseria Gonorrhoeae, Ashley Greenawalt Jan 2021

Targeting Transferrin Binding Protein A For Vaccine Development In Neisseria Gonorrhoeae, Ashley Greenawalt

Theses and Dissertations

Neisseria gonorrhoeae, the causative agent of the sexually-transmitted infection gonorrhea, has recently been labeled a superbug. With dwindling treatment options, there is urgent need for a gonococcal vaccine. TonB-dependent transporters (TDTs) are important gonococcal virulence factors that allow the gonococcus to pirate metals directly from host proteins. The TDTs, TbpA and TbpB, are promising vaccine targets because both proteins are expressed and highly conserved in gonococcal strains, and they are not subject to high-frequency antigenic variation. Because the Tbps bind to host protein as their natural function, our immune system does not recognize them as foreign antigens; thus, immunogenicity is …

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The Influence Of Infant Formula On The Growth Of Commensal And Pathogenic Streptococcus Species In The Infant Oral Cavity, Geneva Waynick Jan 2021

The Influence Of Infant Formula On The Growth Of Commensal And Pathogenic Streptococcus Species In The Infant Oral Cavity, Geneva Waynick

Undergraduate Honors Theses

The oral microbiome is a complex community of microorganisms that can both reflect and greatly influence the health of the human host. A number of diseases are associated with dysbiotic oral microflora in infants and children, including dental (e.g. dental caries, gingivitis, and periodontal disease), and gastrointestinal diseases (e.g. pediatric appendicitis, celiac disease, and pediatric inflammatory bowel disease). A variety of factors can influence the composition of the oral microbial community in infants, including gestation length, mode of delivery, feeding method, and diet. This study focuses on the effects of diet on the growth of a commensal bacterium (Streptococcus …

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Identification Of Blda As A Major Regulator Of Virulence In The Sweetpotato Soil Rot Pathogen Streptomyces Ipomoeae And Characterization Of Distinct Clostridium Sweetpotato Soft Rot Isolates, Kuei-Ting Yang Dec 2020

Identification Of Blda As A Major Regulator Of Virulence In The Sweetpotato Soil Rot Pathogen Streptomyces Ipomoeae And Characterization Of Distinct Clostridium Sweetpotato Soft Rot Isolates, Kuei-Ting Yang

LSU Doctoral Dissertations

Streptomyces ipomoeae is the causative agent of Streptomyces soil rot on sweetpotato, a disease characterized by extensive necrosis of both adventitious and storage roots. While Streptomyces potato scab pathogens produce a phytotoxin (thaxtomin A), which is induced in the presence of cellobiose and suberin, S. ipomoeae produces a less-modified, phytotoxin (thaxtomin C), whose inducer has not been identified. To investigate transcriptional regulation of thaxtomin C production, we inserted a promoter involved in thaxtomin C synthesis upstream of the gusA reporter in an S. ipomoeae strain. Reporter gene expression was significantly upregulated in the presence of size-fractionated sweetpotato extract (SPE). The …

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Pandemic Vibrio Cholerae Shuts Down Site-Specific Recombination To Retain An Interbacterial Defence Mechanism, Francis J. Santoriello, Lina Michel, Daniel Unterweger, Stefan Pukatzki Dec 2020

Pandemic Vibrio Cholerae Shuts Down Site-Specific Recombination To Retain An Interbacterial Defence Mechanism, Francis J. Santoriello, Lina Michel, Daniel Unterweger, Stefan Pukatzki

Publications and Research

Vibrio cholerae is an aquatic microbe that can be divided into three subtypes: harmless environmental strains, localised pathogenic strains, and pandemic strains causing global cholera outbreaks. Each type has a contact-dependent type VI secretion system (T6SS) that kills neighbouring competitors by translocating unique toxic effector proteins. Pandemic isolates possess identical effectors, indicating that T6SS effectors may affect pandemicity. Here, we show that one of the T6SS gene clusters (Aux3) exists in two states: a mobile, prophage-like element in a small subset of environmental strains, and a truncated Aux3 unique to and conserved in pandemic isolates. Environmental Aux3 can be readily …

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Examining Pathogenesis And Preventatives In Spontaneous And Staphylococcus-Induced Bacterial Chondronecrosis With Osteomyelitis In Broilers, Nnamdi Simon Ekesi Dec 2020

Examining Pathogenesis And Preventatives In Spontaneous And Staphylococcus-Induced Bacterial Chondronecrosis With Osteomyelitis In Broilers, Nnamdi Simon Ekesi

Graduate Theses and Dissertations

Bacterial chondronecrosis with osteomyelitis is the most important cause of lameness in broilers. This is important to poultry production, as it poses animal welfare issues, and causes a significant loss in revenue. The remediation of this disease requires the study of its etiology with fitting models and evaluating preventatives. The research reported herein covers genomic virulence analysis of BCO isolates, mainly Staphylococcus aureus, and Escherichia coli retrieved from lame birds. We found that S. aureus isolates were closest to chicken strains in Europe but may have been in the Arkansas area for a decade. Phylogenomics suggest our S. aureus is …

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