David G Bermudes

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Systemically administered tumor-targeted Salmonella has been developed as an anticancer agent, although its use could be limited by the potential induction of tumor necrosis factor alpha (TNFalpha)-mediated septic shock stimulated by lipid A. Genetic modifications of tumor-targeting Salmonella that alter lipid A and increase safety must, however, retain the(More)
Live bacteria were first actively used in the treatment of cancer nearly 150 years ago, work that ultimately led to the study of immunomodulation. Today, with the discovery of bacterial strains that specifically target tumours, and aided by genomic sequencing and genetic engineering, there is new interest in the use of bacteria as tumour vectors.(More)
Studies were conducted on the hypothesis that melanoma metastasis might be initiated through the gener-ation of hybrids comprised of cells of the primary tumor and tumor-infiltrating leukocytes. Fusion hybrids were generated in vitro between weakly metastatic Cloudman S91 mouse melanoma cells and normal mouse or human macrophages. Hybrids were implanted(More)
There has been little investigation of bacteria as gene delivery vectors. Here, we demonstrate that genetically engineered Salmonella have many of the desirable properties of a delivery vector, including targeting of multiple tumors from a distant inoculation site, selective replication within tumors, tumor retardation, and the ability to express effector(More)
GRA3 is a 30-kDa protein located inside the dense granules of Toxoplasma gondii. Following invasion and exocytosis of dense granules within the parasitophorous vacuole, GRA3 becomes associated with the parasitophorous vacuolar membrane (PVM) and extensions of the PVM which protrude into the cytoplasm. A partial cDNA encoding GRA3 was isolated from a(More)
Roots of thirty-eight Ecuadoran vascular epiphytes, representing eleven angiosperm families, were examined for the presence of symbiotic microorganisms. Most orchid roots contained fungal endophytes like those that regularly infect terrestrial counterparts. Hyphae were also common in and on nonorchid roots, but assignments of these relationships to known(More)
The obligate intracellular parasite Toxoplasma gondii produces a nucleoside triphosphate hydrolase (NTPase) (nucleoside-triphosphatase, EC activable by dithiol-containing compounds. We have isolated the genomic DNA for the NTPase from the RH strain of Toxoplasma and determined the nucleotide sequence of three tandemly arranged open reading frames(More)
VNP20009 is a genetically modified strain of Salmonella typhimurium possessing an excellent safety profile, including genetically stable attenuated virulence (a deletion in the purI gene), reduction of septic shock potential (a deletion in the msbB gene), and antibiotic susceptibility. VNP20009 is genetically stable after multiple generations in vitro and(More)
The fate ofToxoplasma gondii dense-granule (GRA2, GRA3), rhoptry (ROP1), and surface (SAG1) proteins was followed by immunofluorescence assay (IFA) and immunoelectron microscopy at different stages after infection. Dense-granule exocytosis occurred in the apical area of the tachyzoite within minutes of invasion. Several exocytic events were found(More)
Lipid A, a potent endotoxin which can cause septic shock, anchors lipopolysaccharide (LPS) into the outer leaflet of the outer membrane of gram-negative bacteria. MsbB acylates (KDO)(2)-(lauroyl)-lipid IV-A with myristate during lipid A biosynthesis. Reports of knockouts of the msbB gene describe effects on virulence but describe no evidence of growth(More)