Samantha S. Orchard

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Members of the genus Xenorhabdus are entomopathogenic bacteria that associate with nematodes. The nematode-bacteria pair infects and kills insects, with both partners contributing to insect pathogenesis and the bacteria providing nutrition to the nematode from available insect-derived nutrients. The nematode provides the bacteria with protection from(More)
Virulence of the insect pathogen Xenorhabdus nematophila is attributed in part to its ability to suppress immunity. For example, X. nematophila suppresses transcripts encoding several antimicrobial proteins, even in the presence of Salmonella enterica, an inducer of these transcripts. We show here that virulence and immune suppression phenotypes can be lost(More)
The bacterium Xenorhabdus nematophila is a mutualist of Steinernema carpocapsae nematodes and a pathogen of insects. Presently, it is not known what nutrients the bacterium uses to thrive in these host environments. In other symbiotic bacteria, oligopeptide permeases have been shown to be important in host interactions, and we therefore sought to determine(More)
Penicillium menonorum is described as a new monoverticillate, non-vesiculate species that resembles P. restrictum and P. pimiteouiense. On the basis of phylogenetic analysis of DNA sequences from four loci, P. menonorum occurs in a clade with P. pimiteouiense, P. vinaceum, P. guttulosum, P. rubidurum, and P. parvum. Genealogical concordance analysis was(More)
BACKGROUND The tdk gene (encoding deoxythymidine kinase) of the gamma-proteobacterium Xenorhabdus nematophila has two potential translation start sites. The promoter-distal start site was predicted to be functional based on amino acid sequence alignment with closely related Tdk proteins. However, to experimentally determine if either of the two possible(More)
Xenorhabdus nematophila is a mutualist of entomopathogenic nematodes and a pathogen of insects. To begin to examine the role of pyrimidine salvage in nutrient exchange between X. nematophila and its hosts, we identified and mutated an X. nematophila tdk homologue. X. nematophila tdk mutant strains had reduced virulence toward Manduca sexta insects and a(More)
The peptide wrwycr inhibits Holliday junction resolution and is a potent antimicrobial. To study the physiological effects of wrwycr treatment on Escherichia coli cells, we partially screened the Keio collection of knockout mutants for those with increased sensitivity to wrwycr. Strains lacking part of the ferric-enterobactin (iron-bound siderophore) uptake(More)
Conservative site-specific recombination has been adapted for a multitude of uses, in both prokaryotes and eukaryotes, including genetic engineering, expression technologies, and as probes of chromosome structure and organization. In this article, we give a specific example of the latter application, and a quick summary of some of the myriad other genetic(More)
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