Pathogenic Microbiology Commons^™

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 …

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 …

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 …

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 …

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 …

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.), …

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 …

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, …

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 …

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 …

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; …

Discovery Of A Novel Antibiotic From A Bacillus Bacterium Cultivated From Its Natural Environment, Patrick J. Mcmonagle

Lawrence University Honors Projects

The current primary method of treating bacterial infections is using antibiotics. However, this continued treatment of these illnesses caused by pathogenic bacteria is causing the rate of evolution of these disease-inducing organisms to increase. Antibiotic resistance is forcing scientists to search for new forms of antibiotics to compete with these new ‘super bugs.’ I pursued the search for novel antibiotics through their natural source – antibiotic-producing microorganisms. As microbes have a direct advantage when producing antibiotics, it is my thought that they will be the best resource to discovering new and effective antibiotics. I conducted an exploratory search for antibiotic-producing …

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, …

Utilization Of Natural Green Tea And Grape Seed Extracts And Nisin To Reduce Conventional Chemical Preservatives And To Inhibit The The Growth Of Listeria Monocytogenes In Ready To Eat Low And High Fat Chicken And Turkey Hotdogs, Amara Venkata Sunil Perumalla

Graduate Theses and Dissertations

Ready-to-eat meat (RTE) products such as hotdogs represent a popular segment in convenience food purchases. Increased demand has led the processors to extend the shelf life by minimizing lipid oxidation and post-processing contaminants such as Listeria monocytogenes. There is a growing interest in the food processors and consumers regarding the use of natural alternatives in place of synthetic food additives to control the growth of foodborne pathogens and (or) lipid oxidation. In recent years, green tea (GTE) and grape seed extracts (GSE) are increasing choices as they have demonstrated antioxidant as well as antimicrobial properties in various food applications. …

Cell-Mediated Immunity In Porcine Reproductive And Respiratory Syndrome Virus, Rajeshwari Parida

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

Porcine reproductive and respiratory syndrome virus is a significant swine pathogen which exhibits considerable sequence diversity. In an attempt to identify highly conserved T-cell epitopes contained in proteins of this virus, we examined heptadecamer peptides spanning the sequence of the PRRSV nonstructural proteins 9, 10 and 11, all of them are highly conserved, for their ability to elicit a recall proliferative and interferon-gamma response in peripheral blood mononuclear cells obtained from pigs immunized against the type-II PRRSV strain FL-12. These studies led to the identification of seven peptides, two from each NSP 9 and NSP 10 and, three from NSP …

Role Of Lactic Acid Bacteria As A Bio-Sanitizer To Prevent Attachment Of Listeria Monocytogenes On Deli Slicer Contact Surfaces, And The Influence Of Listeria Innocua On The Attachment Of L. Monocytogenes On Selected Materials Located In The Food-Processing Environment, Jean Baptiste Ndahetuye

Graduate Theses and Dissertations

Listeria monocytogenes an important foodborne pathogen that continues to be a serious problem for the food industry. This pathogen contaminates food primarily during post-harvest in the food-processing environment. Its ecology in the food-processing environment is not well understood but previous research has demonstrated the ability of L. monocytogenes to survive on food contact surfaces after cleaning and disinfection. The current study explored the attachment of three lactic acid bacteria (LAB) strains, Lactobacillus animalis , Lb. amylovorus and Pediococcus acidilactici , their combination in a cocktail, and their influence to prevent the attachment of L. monocytogenes at room temperature by examining …

Functional Characterization Of Atxa, The Bacillus Anthracis Virulence Regulator, Troy G. Hammerstrom

Dissertations and Theses (Open Access)

Coordinated expression of virulence genes in Bacillus anthracis occurs via a multi-faceted signal transduction pathway that is dependent upon the AtxA protein. Intricate control of atxA gene transcription and AtxA protein function have become apparent from studies of AtxA-induced synthesis of the anthrax toxin proteins and the poly-D-glutamic acid capsule, two factors with important roles in B. anthracis pathogenesis. The amino-terminal region of the AtxA protein contains winged-helix (WH) and helix-turn-helix (HTH) motifs, structural features associated with DNA-binding. Using filter binding assays, I determined that AtxA interacted non-specifically at a low nanomolar affinity with a target promoter (Plef) …

Control Of The Master Virulence Regulatory Gene Atxa In Bacillus Anthracis, Jennifer L. Dale

Dissertations and Theses (Open Access)

Transcription of the Bacillus anthracis structural genes for the anthrax toxin proteins and biosynthetic operon for capsule are positively regulated by AtxA, a transcription regulator with unique properties. Consistent with the role of atxA in virulence factor expression, a B. anthracis atxA-null mutant is avirulent in a murine model for anthrax. In batch culture, multiple signals impact atxA transcript levels, and the timing and steady state level of atxA expression is critical for optimal toxin and capsule synthesis. Despite the apparent complex control of atxA transcription, only one trans-acting protein, the transition state regulator AbrB, has been demonstrated …

Genome-Wide Identification Of Conditionally Essential Genes In Salmonella Typhimurium Using Tn-Seq Method, Anita Khatiwara

Graduate Theses and Dissertations

ABSTRACT

As more whole genome sequences become available, there is an increasing need for high-throughput methods that link genes to phenotypes and facilitate discovery of new gene functions. The objective of this study was to develop a high-throughput method to study gene functions in bacteria and use this method to study gene functions of S. enterica serotype Typhimurium (S. Typhimurium) under various environmental conditions encountered during its life cycle. Chapter I of this dissertation reviews the history and evolution of functional genomics in bacteria with focus on Salmonella, along with the recent techniques available. Chapter II, deals with the development …

Effects Of The Parasitic Dinoflagellate Hematodinium Sp. On Blue Crab (Callinectes Sapidus) Activity Predation And Habitat Selection, John M. Tiggelaar Ii

Biological Sciences Theses & Dissertations

The blue crab Callinectes sapidus occurs along the Atlantic and Gulf coasts of the United States, and in high salinity regions, they are subject to lethal infection by the parasitic dinoflagellate Hematodinium. In Virginia's seaside estuaries, the prevalence of Hematodinium infection of C. sapidus can sometimes exceed 50%, threatening the commercial fishery for this species. Indeed, other commercially important crustacean fisheries have approached collapse due to Hematodinium infections. Most studies of this host-parasite interaction have focused on epidemiology, host-pathogen dynamics, and pathogen transmission, and little is known about the impact of the parasite on host behavior and population dynamics. …

Antifungal Activity Of Lactobacillus Against Microsporum Canis, Microsporum Gypseum And Epidermophyton Floccosum, Jiahui Guo, Brid Brosnan, Ambrose Furey, Elke K. Arendt, Padraigin Murphy

Department of Biological Sciences Publications

A total of 220 lactic acid bacteria isolates were screened for antifungal activity using Aspergillus fumigatus and Aspergillus niger as the target strains. Four Lactobacillus strains exhibited strong inhibitory activity on agar surfaces. All four were also identified as having strong inhibitory activity against the human pathogenic fungi Microsporum canis, Microsporum gypseum and Epidermophyton floccosum. One of the four lactobacilli, namely Lb. reuteri ee1p exhibited the most inhibition against dermatophytes. Cell-free culture supernatants of Lb. reuteri ee1p and of the non-antifungal Lb. reuteri M13 were freeze-dried and used to access and compare antifungal activity in agar plate assays …

Biology And Pathogenesis Of Acanthamoeba., Ruqaiyyah Siddiqui, Naveed Ahmed Khan

Department of Biological & Biomedical Sciences

Acanthamoeba is a free-living protist pathogen, capable of causing a blinding keratitis and fatal granulomatous encephalitis. The factors that contribute to Acanthamoeba infections include parasite biology, genetic diversity, environmental spread and host susceptibility, and are highlighted together with potential therapeutic and preventative measures. The use of Acanthamoeba in the study of cellular differentiation mechanisms, motility and phagocytosis, bacterial pathogenesis and evolutionary processes makes it an attractive model organism. There is a significant emphasis on Acanthamoeba as a Trojan horse of other microbes including viral, bacterial, protists and yeast pathogens.

Changes To The Equine Hindgut Microflora In Response To Antibiotic Challenge, Brittany E. Harlow

Theses and Dissertations--Animal and Food Sciences

Antibiotics are important to equine medicine, but can cause detrimental side-effects including reduced feed intake, allergic reactions, and diarrhea. Antibiotic-associated diarrhea (AAD) is attributed to disruption of the hindgut microflora, permitting proliferation of pathogenic microbes. The objectives were to evaluate the effects of antibiotics on beneficial fecal bacteria, AAD-associated pathogens, microbial species richness and fermentation. Horses were assigned to treatment groups: control (no antibiotics, n=6), trimethoprim-sulfadiazine (oral, n=6), or sodium ceftiofur (IM, n=6). Fecal samples were taken during adaptation (3 wk), antibiotic challenge (1 wk), and withdrawal (1 wk). Fecal cellulolytics decreased by >99% during challenge and did not recover …

In Silico Prediction Of Protein-Protein Interactions Between Cronobacter Sakazakii And Human Host, Sean Held

Theses

The genus Cronobacter accommodates 16 biogroups of the emerging opportunistic pathogen known formerly as Enterobacter sakazakii. Cronobacter are occasional contaminants of milk powder and, consequently, powdered infant formula (PIT). Since it is a pathogen that is transmitted in infant formula it represents a significant health risk to neonates. These bacteria are opportunistic pathogens (can only cause disease when the host's resistance is low) and are linked with life-threatening infections in neonates. Some of the clinical symptoms of Cronohacter infection include necrotizing enterocolitis, bacteremia, and meningitis, with case fatality rates of 50-80% being reported (Healy et al. 2010). Infant formula manufacturers …