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Pathogenic Microbiology Commons

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2012

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Articles 1 - 23 of 23

Full-Text Articles in Pathogenic Microbiology

Efficacy Of Biopesticides For Organic Management Of Cucumber Beetles, Mary A. Rogers Dec 2012

Efficacy Of Biopesticides For Organic Management Of Cucumber Beetles, Mary A. Rogers

Doctoral Dissertations

Organic growers are limited in crop protection techniques for cucumber beetle management. Spotted (Diabrotica undecimpunctata howardi) and striped (Acalymma vitatta) cucumber beetles and are significant pests of cucurbits in the U.S. Feeding results in aesthetic damage and reduction in marketable yields as well as transmission of bacterial wilt that can result in plant mortality. Biopesticides are products formulated from naturally occurring organisms such as fungi and bacteria that are pathogenic or toxic to insect pests. Advantages to these products are that they have low environmental risk, low risk to non-target organisms including mammals and beneficial insects, and can help ...


Investigation Into Potential Cross-Resistance Of Enterococcus Faecalis Og1rf Induced By Adaptation To Nacl And Subsequent Sds Challenge, Vidisha Singh Dec 2012

Investigation Into Potential Cross-Resistance Of Enterococcus Faecalis Og1rf Induced By Adaptation To Nacl And Subsequent Sds Challenge, Vidisha Singh

Chancellor’s Honors Program Projects

No abstract provided.


Fatty Acid Synthase 1 In Candida Albicans Virulence And The In Vitro Effects Of Fluconazole, Tetracycline In Combinatorial Therapy, Marissa Mandy Rodrigues Dec 2012

Fatty Acid Synthase 1 In Candida Albicans Virulence And The In Vitro Effects Of Fluconazole, Tetracycline In Combinatorial Therapy, Marissa Mandy Rodrigues

Masters Theses

Candida albicans, the causative agent of superficial and invasive mycoses, is a significant fungal pathogen associated with high mortality rates and considerable health-related costs. The most effective class of antifungals used for the treatment of candidiasis includes polyenes, echinocandins and azoles. However with the emergence of resistant strains, new antifungals are warranted for the effective treatment of candidiasis. Genes involved in biosynthetic enzymatic pathways that regulate metabolic processes are important for the survival of pathogenic fungi and can thus be exploited for the development of better antifungals. Fatty acid synthase 1, which is involved in the de novo biosynthesis of ...


Staphylococcus Aureus Response To Long Chain Antimicrobial Fatty Acids, Benjamin Arsic Sep 2012

Staphylococcus Aureus Response To Long Chain Antimicrobial Fatty Acids, Benjamin Arsic

Electronic Thesis and Dissertation Repository

Staphylococcus aureus is a common pathogen that has the ability to infect virtually every tissue and organ system of the body. Despite its propensity to cause invasive infection, S. aureus is also a commensal organism, asymptomatically colonizing ~25% of the population. Much research has gone into resolving this paradox, focusing on both human and bacterial factors that may contribute to colonization. Antimicrobial fatty acids present on the skin and in the nasal mucosa are important components of the innate immune system, and thus we undertook to further understand how S. aureus responds to these fatty acids, and how this response ...


Empower Research Through Comparative Genomics & Next-Gen Sequencing, Li-Jun Ma Sep 2012

Empower Research Through Comparative Genomics & Next-Gen Sequencing, Li-Jun Ma

Li-Jun Ma

Describes research in comparative fungal genomics, specifically the the plant-fungal interactions of wilt diseases caused by Fusarium oxysporum.


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 Aug 2012

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 real-time ...


Quorum Sensing And Other Aspects Of The Biology Of Candida Albicans, Kenneth W. Nickerson Aug 2012

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 that ...


Regulation Of Toxin Synthesis By Clostridium Difficile, Charles Darkoh Aug 2012

Regulation Of Toxin Synthesis By Clostridium Difficile, Charles Darkoh

UT GSBS 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 ...


The Pseudomonas Syringae Type Iii Secretion System: The Translocator Proteins, Their Secretion, And The Restriction Of Translocation By The Plant Immune System, Emerson Crabill Jul 2012

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

Dissertations and Theses in Biological Sciences

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 ...


Host Pathogen Interactions: Is Arabidopsis Thaliana Remembered By Its Nemesis Pseudomonas Syringae?, Daniel Z. Kreiser May 2012

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, suggesting that ...


Discovery Of A Novel Antibiotic From A Bacillus Bacterium Cultivated From Its Natural Environment, Patrick J. Mcmonagle May 2012

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 microbes ...


Empower Research Through Comparative Genomics & Next-Gen Sequencing, Li-Jun Ma May 2012

Empower Research Through Comparative Genomics & Next-Gen Sequencing, Li-Jun Ma

UMass Center for Clinical and Translational Science Research Retreat

Describes research in comparative fungal genomics, specifically the the plant-fungal interactions of wilt diseases caused by Fusarium oxysporum.


Functional Characterization Of Atxa, The Bacillus Anthracis Virulence Regulator, Troy G. Hammerstrom May 2012

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

UT GSBS 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) and ...


Control Of The Master Virulence Regulatory Gene Atxa In Bacillus Anthracis, Jennifer L. Dale May 2012

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

UT GSBS 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 ...


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 May 2012

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

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. Therefore ...


Genome-Wide Identification Of Conditionally Essential Genes In Salmonella Typhimurium Using Tn-Seq Method, Anita Khatiwara May 2012

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

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 ...


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 May 2012

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

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 their cell ...


Biology And Pathogenesis Of Acanthamoeba., Ruqaiyyah Siddiqui, Naveed Ahmed Khan Jan 2012

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.


Thoughts On Quorum Sensing And Fungal Dimorphism, Kenneth W. Nickerson, Audrey L. Atkin, Jessica C. Hargarten, Ruvini U. Pathirana, Sahar Hasim Jan 2012

Thoughts On Quorum Sensing And Fungal Dimorphism, Kenneth W. Nickerson, Audrey L. Atkin, Jessica C. Hargarten, Ruvini U. Pathirana, Sahar Hasim

Papers in Microbiology

Farnesol has been best studied for its role in regulating fungal dimorphism. However, farnesol is also a lipid and in this review we analyze data relevant to farnesol’s function and synthesis from the perspective of farnesol and bacterial endotoxins acting as membrane active compounds. This analysis implicates the possible roles of: (1) endotoxins in the regulation of farnesol production by C. albicans; (2) farnesol in the interactions between C. albicans and the host during disseminated infections; and (3) ubiquinones in the mechanisms for unusually high resistance to farnesol by some C. albicans cell types. Finally we discuss the implications ...


Quorum Sensing Activity In Ophiostoma Ulmi: Effects Of Fusel Oils And Branched Chain Amino Acids On Yeast-Mycelial Dimorphism, A. Berrocal, J. Navarrete, C. Oviedo, K. W. Nickerson Jan 2012

Quorum Sensing Activity In Ophiostoma Ulmi: Effects Of Fusel Oils And Branched Chain Amino Acids On Yeast-Mycelial Dimorphism, A. Berrocal, J. Navarrete, C. Oviedo, K. W. Nickerson

Kenneth Nickerson Papers

Aims: For Ophiostoma (Ceratocystis) ulmi, the ability to undergo morphological change is a crucial factor for its virulence. To gain an understanding of quorum- sensing activity in O. ulmi as it relates to yeast-mycelium dimorphism control, this study examines the effects of branched-chain amino acids as well as their fusel alcohols and fusel acids as quorum sensing molecules.

Methods and Results: In a defined medium containing glucose, proline and salts, O. ulmi grew as yeasts when the culture was inoculated with a high density of spores (2-107 CFU ml-1) and as mycelia when inoculated with a low spore ...


Letter From The Dean, Michael Vayda Jan 2012

Letter From The Dean, Michael Vayda

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.


Changes To The Equine Hindgut Microflora In Response To Antibiotic Challenge, Brittany E. Harlow Jan 2012

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 ...


Morphological, Anatomical And Molecular Investigation Into Witches’ Broom Disease Of Mamejvo (Enicostemma Axillare), K. Abirami, Anjali Sharma, Jatindra Nath Samanta, V. S. Rana, Kunal Mandal Dec 2011

Morphological, Anatomical And Molecular Investigation Into Witches’ Broom Disease Of Mamejvo (Enicostemma Axillare), K. Abirami, Anjali Sharma, Jatindra Nath Samanta, V. S. Rana, Kunal Mandal

Kunal Mandal

Mamejvo (Enicostemma axillare Raynal) is a perennial herb with diversified health benefits. It was found to be affected by a witches’ broom disease under the field conditions at Anand, Gujarat, India. Affected plants were 53.33% reduced in height due to shortened internodes, leading to typical witches’ broom symptoms. Flower size was reduced significantly in the affected plants compared with the healthy ones and their petal color gradually turned green (virescence). Affected plants produced 2.5 times more dry herbage than the normal plants but with less active ingredient (swertiamarin). Symptomatic plants died early while root suckers from such plants ...