Pathogenic Microbiology Commons^™

Neuropathogenic Escherichia Coli K1 Does Not Exhibit Proteolytic Activities To Exert Its Pathogenicity, Junaid Iqbal, Mehak Rajan, Ruqaiyyah Siddiqu, Naveed Ahmed Khan

Department of Biological & Biomedical Sciences

Background: Proteases are well-known virulence factors that promote survival, pathogenesis and immune evasion of many pathogens. Several lines of evidence suggest that the blood-brain barrier permeability is a prerequisite in microbial invasion of the central nervous system. Because proteases are frequently associated with vascular permeability by targeting junctional proteins, here it is hypothesized that neuropathogenic Escherichia coli K1 exhibit proteolytic activities to exert its pathogenicity.
Methods: Zymographic assays were performed using collagen and gelatin as substrates. The lysates of whole E. coli K1 strain E44, or E. coli K-12 strain HB101 were tested for proteolytic activities. The conditioned media were …

Changes In Bacterial Growth Rate Govern Expression Of The Borrelia Burgdorferi Ospc And Erp Infection-Associated Surface Proteins, Brandon L. Jutras, Alicia M. Chenail, Brian Stevenson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The Lyme disease spirochete controls production of its OspC and Erp outer surface proteins, repressing protein synthesis during colonization of vector ticks but increasing expression when those ticks feed on vertebrate hosts. Early studies found that the synthesis of OspC and Erps can be stimulated in culture by shifting the temperature from 23°C to 34°C, leading to a hypothesis that Borrelia burgdorferi senses environmental temperature to determine its location in the tick-mammal infectious cycle. However, borreliae cultured at 34°C divide several times faster than do those cultured at 23°C. We developed methods that disassociate bacterial growth rate and temperature, allowing …

Detection Of Viable Microorganisms Using Propidium Monoazide, Erik J. Mcfarland, Adrian Ponce Dr.

STAR Program Research Presentations

Propidium monoazide (PMA) is a molecular tool used to assess viability of microorganisms. Currently, PMA is thought to discern viability through membrane permeability; PMA enters only membrane compromised cells, irreversibly crosslinks to theirDNAand precipitates theDNAout of solution, preventing it from being amplified during polymerase chain reaction (PCR). Using PMA on a sample of live and dead microorganisms results in only theDNAof living organisms being amplified and identified. Therefore, a comparison ofPCRresults with and without PMA allows one to determine the live fraction and total population, respectively.

Current literature provides conflicting evidence as to the effectiveness of the technique. Our research …

Candida Albicans Czf1 And Efg1 Coordinate The Response To Farnesol During Quorum Sensing, White-Opaque Thermal Dimorphism, And Cell Death, Melanie L. Langford, Jessica C. Hargarten, Krista D. Patefield, Elizabeth Marta, Jill R. Blankenship, Saranna Fanning, Kenneth W. Nickerson, Audrey L. Atkin

Kenneth Nickerson Papers

Quorum sensing by farnesol in Candida albicans inhibits filamentation and may be directly related to its ability to cause both mucosal and systemic diseases. The Ras1-cyclic AMP signaling pathway is a target for farnesol inhibition. However, a clear understanding of the downstream effectors of the morphological farnesol response has yet to be unraveled. To address this issue, we screened a library for mutants that fail to respond to farnesol. Six mutants were identified, and the czf1/czf1 mutant was selected for further characterization. Czf1 is a transcription factor that regulates filamentation in embedded agar and also whiteto- opaque switching. We found …

Antilisterial Characteristics Of Volatile Essential Oils, Leeann L. Slaughter

Theses and Dissertations--Animal and Food Sciences

This study explored the in vitro and in situ antilisterial inhibitory activity of 16 essential oils during indirect exposure: Spanish Basil oil (Ocimum basilicum), Bay oil (Pimenta racemosa), Italian Bergamot oil (Citrus bergamia), Roman Chamomile oil (Anthemis nobilis), Sir Lanka Cinnamon oil (Cinnamomum zeylanicum), Citral, Clove Bud oil (Syzygium aromaticum), Cumin Seed oil (cuminum cyminum), Eucalyptus oil (Eucalyptus globulus), Eugenol, Geranium extract (Pelargonium graveolens), Marjoram oil (Origanum majorana), Neroli extract (Citrus aurantium), Peppermint oil (Mentha piperita L.), …

Equine Serum Antibody Responses To Streptococcus Equi And Streptococcus Zooepidemicus, Rafaela De Negri

Theses and Dissertations--Veterinary Science

Streptococcus zooepidemicus (Sz) and Streptococcus equi (Se) share 98% DNA sequence homology, but display different pathogenic properties. Infection by one organism does not cross-protect against the other. To better understand pathogenic differences between these organisms and gain information about which proteins are expressed in horses infected experimentally with Se, intrauterine Sz or naturally with respiratory Sz we compared antibody specificities of convalescent sera using ELISA. These comparisons were based on sets of 8 and 14 immunoreactive recombinant proteins of Se strain CF32 and Sz strain NC78, respectively. Sera from donkeys that were previously naturally affected with strangles and later developed …

Identification And Characterisation Of Campylobacter Ureolyticus: A New And Emerging Gastrointestinal Pathogen, Susan Bullman

Theses

Campylobacter jejuni is universally recognized as the leading bacterial cause of human gastroenteritis. However, within recent years a growing number of non- jejuni/coli Campylobacter species have been acknowledged as emerging human and animal pathogens. Advances in molecular diagnostics and development of pioneering culture methodologies have led to the detection of a range of under-appreciated and nutritionally fastidious Campylobacter species, including C. ureolyticus. Herein, we provide the first report of C ureolyticus in the faeces of patients presenting with gastroenteritis and suggest a role for this organism as an emerging enteric pathogen.

Employing a two-tiered molecular study, we report C. ureolyticus …

Development Of A Recombinant Lactobacillus Salivarius For Prophylactic Applications Against Mycobacterium Avium Subspecies Paratuberculosis And Johne’S Disease, Christopher Johnston

Theses

Current whole-cell vaccines against Mycobacterium avium subsp. paratuberculosis, the etiological agent of Johne’s disease, are unable to provide complete protection against infection. Moreover, such whole-cell formulations interfere with diagnostic tests for bovine tuberculosis (Mycobacterium bovis). The development of subunit vaccines, those which are preferentially based on one, or a select few, immunodominant protective antigens is considered as the realistic next step in overcoming these issues. The (MAP) K-10 genome is a single circular chromosome of 4,829,781 base pairs and encodes 4,350 predicted ORFs. In order to identify MAP specific proteins for subsequent incorporation within a mucosal based vaccine development, a …

Neisseria Oralis Sp. Nov., Isolated From Healthy Gingival Plaque And Clinical Samples, William J. Wolfgang, Teresa V. Passaretti, Reashma Jose, Jocelyn Cole, An Coorevits, Andrea N. Carpenter, Sherly Jose, Anita Van Landschoot, Jacques Izard, Donna J. Kohlerschmidt, Peter Vandamme, Floyd E. Dewhirst, Mark A. Fisher, Kimberlee A. Musser

Department of Food Science and Technology: Faculty Publications

A polyphasic analysis was undertaken of seven independent isolates of gram-negative cocci collected from pathological clinical samples from New York, Louisiana, Florida, and Illinois and healthy subgingival plaque from a patient in Virginia, USA. The 16S rRNA gene sequence similarity among these isolates was 99.7–100 %, and the closest species with a validly published name was Neisseria lactamica (96.9 % similarity to the type strain). DNA–DNA hybridization confirmed that these isolates are of the same species and are distinct from their nearest phylogenetic neighbor, N. lactamica. Phylogenetic analysis of 16S and 23S rRNA gene sequences indicated that the …

Histone Biotinylation In Candida Albicans, Sahar Hasim, Swetha Tati, Nandakumar Madayiputhiya, Renu Nandakumar, Kenneth W. Nickerson

Kenneth Nickerson Papers

Candida albicans is an opportunistic fungal pathogen in humans. It is a polymorphic fungus: it can live as yeasts, hyphae, or pseudohyphae. Biotin is required for cell growth and fatty acid metabolism because it is used as a cofactor for carboxylases such as acetyl-CoA carboxylase, and pyruvate carboxylase. In addition, we have discovered that biotin is used to modify histones in C. albicans. Biotinylation was detected by Western blots using a monoclonal antibiotin HRP-conjugated antibody as well as with qTOF and LC/MS/MS mass spectrometry. As a precaution, the antibiotin antibody was dialyzed against neutravidin prior to use. During this study, …

Seroprevalence Of Brucellosis In Livestock Within Three Endemic Regions Of The Country Of Georgia, Eliso Mamisashvili, Ian T. Kracalik, Tinatin Onashvili, Lela Kerdzevadze, Ketevan Goginashvili, Tamar Tigilauri, Marina Donduashvili, Marina Nikolaishvili, Irma Beradze, Marina Zakareishvili, Maka Kokhreidze, Makvala Gelashvili, Nino Vepkhvadze, S. Elizabeth Rácz, Philip H. Elzer, Mikeljon P. Nikolich, Jason K. Blackburn

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Brucellosis is the one of most common livestock zoonoses in Georgia, resulting in significant economic losses. Livestock were sampled in three regions of Georgia (Kakheti, Kvemo Kartli, Imereti). Districts that historically reported high numbers of brucellosis related morbidity were selected for serological, bacteriological and molecular surveys. Surveying efforts yielded samples from 10,819 large and small ruminants. In total, 735 serological tests were positive on Rose Bengal and 33 bacterial isolates were recovered and identified as Brucella melitensis or Brucella abortus by microbiology and AMOS-PCR. A Bayesian framework was implemented to estimate the true prevalence of the disease given an imperfect …

The Isolation And Characterisation Of Acientobacter Baumannii Bacteriophage, Mohamed Farag M. Elbreki

Theses

Acinetobacter baumannii is a pathogen, which has an increasing prevalence of multidrug resistance. It exists widely in natural environments, and frequently in health-care settings where it has proven difficult to eradicate using antibiotic therapy. A possible alternative to conventional antibiotics is the use of bacteriophages (phages) as antibacterials. In this project, extensive screening of environmental samples such as soils, sewage and waters was undertaken to identify suitable phages. Three phages were successfully isolated from municipal waste in the Cork area. These were subsequently characterized in detail and examined by electron microscopy, which showed that they were all of the Myoviridae …

Amelioration Of Root Disease Of Subterranean Clover (Trifolium Subterraneum) By Mineral Nutrients, Tim Scanlon, Tiernan A. O’Rourke, Megan H. Ryan, Martin J. Barbetti, Krishnapillai Sivasithamparam

Journal articles

Subterranean clover (Trifolium subterraneum) is a key pasture legume across southern Australia and elsewhere. Decline in subterranean clover pastures was first recognised in Australia during the 1960s and manifests as an increase in weeds and a decrease in desirable legume species. While both root disease and poor nutrition contribute to subterranean clover pasture decline, the relationships between root disease and nutrition have not been determined. The objective of this study was to define these relationships. Field experiments were undertaken to determine the nutritional and pathogen status of soils and subterranean clover from three Western Australian field sites. Subsequently, …

Quorum Sensing And Other Aspects Of The Biology Of Candida Albicans, Kenneth W. Nickerson

Kenneth Nickerson Papers

Most dimorphic fungi exhibit cell density dependent effects in that they grow as yeasts when inoculated at > 10⁶ cells per ml and as mycelia when inoculated at < 10⁶ cells per ml. For Candida albicans, we discovered (2001) that this phenomenon (quorum sensing) is due to the production and secretion of the C₁₅ isoprenoid trans-trans farnesol. Since then, we found that C. albicans cells treated with sublethal levels of zaragozic acid (2003) or fluconazole (2004) produced 10-40X more farnesol and that these fluconazole treated cells were ca. 5X more toxic to mice following tail vein injection. This suggestion …

Regulation Of To Xin Synthesis By Clostridium Difficile, Charles Darkoh

Dissertations and Theses (Open Access)

Clostridium difficile is the leading definable cause of nosocomial diarrhea worldwide due to its virulence, multi-drug resistance, spore-forming ability, and environmental persistence. The incidence of C. difficile infection (CDI) has been increasing exponentially in the last decade. Virulent strains of C. difficile produce either toxin A and/or toxin B, which are essential for the pathogenesis of this bacterium. Current methods for diagnosing CDI are mostly qualitative tests that detect the bacterium, the toxins, or the toxin genes. These methods do not differentiate virulent C. difficile strains that produce active toxins from non-virulent strains that do not produce toxins or produce …

Inhibition Of Burkholderia Multivorans Adhesion To Lung Epithelial Cells By Bivalent Lactosides, Ciara Wight, Rosaria Leyden, Paul V. Murphy, Máire Callaghan, Trinidad Velasco-Torrijos, Siobhan Mcclean

Articles

Burkholderia cepacia complex (Bcc) is an opportunistic pathogen in cystic fibrosis patients which is inherently resistant to antimicrobial agents. The mechanisms of attachment and pathogenesis of Bcc, a group of 17 species, are poorly understood. The most commonly identified Bcc species in newly colonised patients, Burkholderia multivorans, continues to be acquired from the environment. Development of therapies which can prevent or reduce the risk of colonization on exposure to Bcc in the environment would be a better alternative to antimicrobial agents. Previously, it has been shown that Bcc strains bound to many glycolipid receptors on lung epithelia. Using a …

Cholesterol Degradation Pathways As Therapeutic Targets In Mycobacterium Tuberculosis, Veronica Escalante, Johnathan Abou-Fadel, Rhone A. Mendoza, Hugues Ouellet

COURI Symposium Abstracts, Summer 2012

Mycobacterium tuberculosis (Mtb) is an intracellular pathogen responsible for about 2 million deaths worldwide annually. During infection, Mtb faces the nutrient-deficient environment of the macrophage phagosome and switches to lipids, including cholesterol, as its main source or carbon and energy. Extensive work has been done on the cholesterol AB rings degradation, but much less is known about the degradation of the CD rings and aliphatic side-chain, which are thought to be shortened by β-oxidation reactions. In this study, we investigate the role of four fadD (fadD3, fadD17, fadD19 and fadD36) and eight fadE ( …

The Pseudomonas Syringae Type Iii Secretion System: The Translocator Proteins, Their Secretion, And The Restriction Of Translocation By The Plant Immune System, Emerson Crabill

School of Biological Sciences: Dissertations, Theses, and Student Research

Pseudomonas syringae is a Gram-negative plant pathogen whose virulence is dependent upon its type III secretion system (T3SS), a nanosyringe that facilitates translocation, or injection, of type III effector (T3E) proteins into eukaryotic cells. The primary function of P. syringae T3E proteins is suppression of plant immunity. Bacterial proteins called translocators form a translocon that forms a pore in the host plasma membrane which is traversed by T3Es. HrpK1, a putative P. syringae translocator, is a type III-secreted protein important for virulence and T3E injection, but not secretion of T3Es. Harpins are a group of proteins specific to plant pathogens …

Composition Of The Adult Digestive Tract Bacterial Microbiome Based On Seven Mouth Surfaces, Tonsils, Throat And Stool Samples, Nicola Segata, Susan Kinder Haake, Peter Mannon, Katherine P. Lemon, Levi Waldron, Dirk Gevers, Curtis Huttenhower, Jacques Izard

Department of Food Science and Technology: Faculty Publications

Background: To understand the relationship between our bacterial microbiome and health, it is essential to define the microbiome in the absence of disease. The digestive tract includes diverse habitats and hosts the human body’s greatest bacterial density. We describe the bacterial community composition of ten digestive tract sites from more than 200 normal adults enrolled in the Human Microbiome Project, and metagenomically determined metabolic potentials of four representative sites.

Results: The microbiota of these diverse habitats formed four groups based on similar community compositions: buccal mucosa, keratinized gingiva, hard palate; saliva, tongue, tonsils, throat; sub- and supra-gingival plaques; …

Host Pathogen Interactions: Is Arabidopsis Thaliana Remembered By Its Nemesis Pseudomonas Syringae?, Daniel Z. Kreiser

Lawrence University Honors Projects

Plants contain innate immune systems that deter pathogen infection. Pattern recognition receptors bind microbe-associated molecular patterns (MAMPs), triggering immunity. MAMPs are proteins exclusive to pathogens that are typically indispensable for their survival. For this reason, MAMPs cannot be mutated or removed without causing pathogen death. However, this does not necessitate constitutive expression of MAMPs. In this study, the MAMP response of Arabidopsis thaliana was utilized to determine differential detection of MAMPs expressed by Pseudomonas syringe pv. tomato DC3000 when pretreated with A. thaliana. Results demonstrated that more MAMPs are detected when P. syringae had previously encountered A. thaliana, …