Publications by authors named "James R Theoret"

JorRay, Blocker23, Nibbles, and OlgasClover are actinobacteriophages belonging to clusters G1, B2, CT, and DJ, respectively. JorRay and Blocker23 were identified in host bacterium . Nibbles and OlgasClover were identified in host bacterium NRRL B-16540.

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AnarQue and Figliar are bacteriophages identified from the host bacterium Gordonia rubripertincta NRRL B-16540. AnarQue is circularly permuted and has a length of 61,822 bp; it is assigned to cluster DR. Figliar has a 3' sticky overhang and a length of 61,147 bp; it is assigned to cluster DJ.

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Jodelie19, BlingBling, and Burnsey are bacteriophages identified using host bacteria of the genus Jodelie19 is a lytic phage found in NRRL B-16540. The temperate phage BlingBling and lytic phage Burnsey were both isolated using the host bacterium 3612.

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Jellybones and NHagos are bacteriophages that were identified in the host bacterium NRRL B-16540. Jellybones has a direct terminal repeat and was assigned to the CS2 subcluster with a length of 77,514 bp. NHagos is circularly permuted and was assigned to the DR cluster with a length of 59,580 bp.

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Many strains produce NanI as their major sialidase. Previous studies showed that NanI could potentiate epsilon toxin cytotoxicity by enhancing the binding of this toxin to host cells. The present study first determined that NanI exerts similar cytotoxicity-enhancing effects on enterotoxin and beta toxin, which are also important toxins for diseases (enteritis and enterotoxemia) originating in the gastrointestinal (GI) tract.

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By producing toxins, Clostridium perfringens causes devastating diseases of both humans and animals. C. perfringens beta toxin (CPB) is the major virulence determinant for type C infections and is also implicated in type B infections, but little is known about the CPB structure-function relationship.

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Clostridium perfringens relies upon plasmid-encoded toxin genes to cause intestinal infections. These toxin genes are associated with insertion sequences that may facilitate their mobilization and transfer, giving rise to new toxin plasmids with common backbones. Most toxin plasmids carry a transfer of clostridial plasmids locus mediating conjugation, which likely explains the presence of similar toxin plasmids in otherwise unrelated C.

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The ability of Clostridium perfringens type C to cause human enteritis necroticans (EN) is attributed to beta toxin (CPB). However, many EN strains also express C. perfringens enterotoxin (CPE), suggesting that CPE could be another contributor to EN.

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Clostridium perfringens uses its arsenal of >16 toxins to cause histotoxic and intestinal infections in humans and animals. It has been unclear why this bacterium produces so many different toxins, especially since many target the plasma membrane of host cells. However, it is now established that C.

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Clostridium perfringens enterotoxin (CPE) causes the gastrointestinal symptoms of the second most common bacterial food-borne illness. Previous studies suggested that a region named TM1, which has amphipathic characteristics and spans from amino acids 81 to 106 of the native CPE protein, forms a β-hairpin involved in β-barrel pore formation. To further explore the potential role of TM1 in pore formation, the single Cys naturally present in CPE at residue 186 was first altered to alanine by mutagenesis; the resultant rCPE variant, named C186A, was shown to retain cytotoxic properties.

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In this work, we investigated the Campylobacter jejuni dps (DNA binding protein from starved cells) gene for a role in biofilm formation and cecal colonization in poultry. In vitro biofilm formation assays were conducted with stationary-phase cells in cell culture plates under microaerophilic conditions. These studies demonstrated a significant (>50%) reduction in biofilm formation by the C.

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Iron acquisition is an absolute requirement by most microorganisms for host survival. In this work, we investigated the Campylobacter jejuni iron binding Dps protein for a potential role in virulence. In vitro assays using J774A.

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Clostridium perfringens type A is the most common cause of poultry necrotic enteritis (NE). Of the four "major" toxins, type A strains produce only alpha toxin (CPA), which has long been considered a major factor in pathogenesis of NE. We investigated the virulence for poultry of type A strains from a variety of enteric sources.

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Background: The complex microbiome of the ceca of chickens plays an important role in nutrient utilization, growth and well-being of these animals. Since we have a very limited understanding of the capabilities of most species present in the cecum, we investigated the role of the microbiome by comparative analyses of both the microbial community structure and functional gene content using random sample pyrosequencing. The overall goal of this study was to characterize the chicken cecal microbiome using a pathogen-free chicken and one that had been challenged with Campylobacter jejuni.

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