Transcriptional profiling of the murine cutaneous response during initial and subsequent infestations with Ixodes scapularis nymphs.

Background: Ixodes scapularis ticks are hematophagous arthropods capable of transmitting many infectious agents to humans. The process of blood feeding is an extended and continuous interplay between tick and host responses. While this process has been studied extensively in vitro, no global understanding of the host response to ticks has emerged.

Blood feeding by the Rocky Mountain spotted fever vector, Dermacentor andersoni, induces interleukin-4 expression by cognate antigen responding CD4+ T cells.

Background: Tick modulation of host defenses facilitates both blood feeding and pathogen transmission. Several tick species deviate host T cell responses toward a Th2 cytokine profile. The majority of studies of modulation of T cell cytokine expression by ticks were performed with lymphocytes from infested mice stimulated in vitro with polyclonal T cell activators.

Dermatologic changes induced by repeated Ixodes scapularis bites and implications for prevention of tick-borne infection.

Previous studies in rodents and people have demonstrated that repeated tick exposure is associated with reduced Borrelia burgdorferi transmission but the mechanism of prevention remains unclear. We examined the acute histopathologic reactions to initial and repeated Ixodes scapularis bites in BALB/c mice and in people. Skin biopsies of BALB/c mice infested for the first time by I.

Transcriptome analysis of the salivary glands of Dermacentor andersoni Stiles (Acari: Ixodidae).

Amongst blood-feeding arthropods, ticks of the family Ixodidae (hard ticks) are vectors and reservoirs of a greater variety of infectious agents than any other ectoparasite. Salivary glands of ixodid ticks secrete a large number of pharmacologically active molecules that not only facilitate feeding but also promote establishment of infectious agents. Genomic, proteomic and immunologic characterization of bioactive salivary gland molecules are, therefore, important as they offer new insights into molecular events occurring at the tick-host interface and they have implications for development of novel control strategies.

Confirmation of tick bite by detection of antibody to Ixodes calreticulin salivary protein.

Ticks introduce a variety of pharmacologically active molecules into their host during attachment and feeding in order to obtain a blood meal. People who are repeatedly exposed to ticks may develop an immune response to tick salivary proteins. Despite this response, people usually are unaware of having been bitten, especially if they are not repeatedly exposed to ticks.

An annotated catalog of salivary gland transcripts from Ixodes scapularis ticks.

Over 8000 expressed sequence tags from six different salivary gland cDNA libraries from the tick Ixodes scapularis were analyzed. These libraries derive from feeding nymphs infected or not with the Lyme disease agent, Borrelia burgdorferi, from unfed adults, and from adults feeding on a rabbit for 6-12 h, 18-24 h, and 3-4 days. Comparisons of the several libraries led to identification of several significantly differentially expressed transcripts.

Identification and characterization of a well-defined series of coronatine biosynthetic mutants of Pseudomonas syringae pv. tomato DC3000.

To identify Pseudomonas syringae pv. tomato genes involved in pathogenesis, we carried out a screen for Tn5 mutants of P. syringae pv.

Characterization of a recombinant immunomodulatory protein from the salivary glands of Dermacentor andersoni.

The gene encoding a 36-kDa (p36) immunomodulatory protein present in saliva of Dermacentor andersoni was cloned in prokaryotic and eukaryotic expression vectors. A polymerase chain reaction (PCR)-generated cDNA lacking signal peptide was cloned into the Escherichia coli expression vector pET28 and a similar sequence was cloned into pIB/V5-His-TOPO expression vector for stable transfection of insect cells, High 5 trade mark. The 26-kDa molecular mass of p36 expressed by bacteria is in agreement with that predicted from the translated full-length cDNA sequence.

RpoN (sigma(54)) is required for plasmid-encoded coronatine biosynthesis in Pseudomonas syringae.

The plant pathogen Pseudomonas syringae pv. glycinea PG4180 produces coronatine (COR), a phytotoxin which functions as a virulence factor in bacterial blight of soybeans. The COR biosynthetic gene cluster in PG4180 is borne on a 90-kb plasmid named p4180A.