Michael J. Herron

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We developed and applied transposon-based transformation vectors for molecular manipulation and analysis of spotted fever group rickettsiae, which are obligate intracellular bacteria that infect ticks and, in some cases, mammals. Using the Epicentre EZ::TN transposon system, we designed transposons for simultaneous expression of a reporter gene and a(More)
BACKGROUND Tick-borne pathogens cause emerging zoonoses, and include fastidious organisms such as Anaplasma phagocytophilum. Because of their obligate intracellular nature, methods for mutagenesis and transformation have not been available. RESULTS To facilitate genetic manipulation, we transformed A. phagocytophilum (Ap) to express a green fluorescent(More)
Anaplasma phagocytophilum (Ap) is an obligate intracellular bacterium and the agent of human granulocytic anaplasmosis, an emerging tick-borne disease. Ap alternately infects ticks and mammals and a variety of cell types within each. Understanding the biology behind such versatile cellular parasitism may be derived through the use of tiling microarrays to(More)
A system was described for studying bovine leukotaxis. Chemotaxis was readily observed toward bovine serum activated by zymosan of agarose. However, bacterial culture filtrates and peptides, which were potent chemotaxins for leukocytes from other species, failed to affect bovine leukotaxis. Using conditions suitable for studying binding to leukocytes from(More)
Ixodes scapularis ticks transmit Anaplasma phagocytophilum (Ap), agent of human granulocytic anaplasmosis (HGA). Invasion of neutrophil granulocytes (PMN) by Ap is the hallmark of the disease, but these short-lived phagocytes are not likely the sole cell type required for productive infection. We analyzed infection of microvascular endothelial cells during(More)
Anaplasma marginale and A. phagocytophilum are obligate intracellular, tick-borne pathogens that target erythrocytes and neutrophil granulocytes, respectively. Because ticks do not directly tap blood vessels, an intermediate tissue may mediate infection of blood cells. We considered that vascular endothelium interacts with circulating blood cells in vivo,(More)
Functional and anatomical relationships among primary afferent fibers, blood vessels, and cancers are poorly understood. However, recent evidence suggests that physical and biochemical interactions between these peripheral components are important to both tumor biology and cancer-associated pain. To determine the role of these peripheral components in a(More)
The ability of Candida albicans to establish an infection involves multiple components of this fungal pathogen, but its ability to persist in host tissue may involve primarily the immunosuppressive property of a major cell wall glycoprotein, mannan. Mannan and oligosaccharide fragments of mannan are potent inhibitors of cell-mediated immunity and appear to(More)
Human granulocytic ehrlichiosis (HGE) is a febrile tick-borne illness caused by a recently discovered intracellular bacterium remarkable for its tropism for professionally phagocytic neutrophils. Monoclonal antibodies against the P-selectin binding domain of the leukocyte P-selectin glycoprotein ligand, PSGL-1, prevented HGE cell binding and infection, as(More)