A5090256363- Vector-borne infectious diseases
- Viral Infections and Vectors
- Vector-Borne Animal Diseases
- Insect and Pesticide Research
- Yersinia bacterium, plague, ectoparasites research
- Mosquito-borne diseases and control
- Insect symbiosis and bacterial influences
- Dermatological diseases and infestations
- Zoonotic diseases and public health
- Bacillus and Francisella bacterial research
- Viral Infections and Outbreaks Research
- Animal Ecology and Behavior Studies
- Toxin Mechanisms and Immunotoxins
- Plant Virus Research Studies
- Study of Mite Species
- Insect and Arachnid Ecology and Behavior
- Bird parasitology and diseases
- Plant-based Medicinal Research
- Insect-Plant Interactions and Control
- Animal Disease Management and Epidemiology
- Invertebrate Immune Response Mechanisms
- Disaster Response and Management
- Aquatic Ecosystems and Biodiversity
- Species Distribution and Climate Change
- Plant and Fungal Interactions Research
University Hospital Heidelberg
2025
Heidelberg University
2025
National Institute of Allergy and Infectious Diseases
2013-2024
National Institutes of Health
2011-2024
Rocky Mountain Biological Laboratory
2009-2017
University of Montana
2008-2015
Medical College of Wisconsin
2009
Tufts University
2009
Tufts Medical Center
2009
Whitney Museum of American Art
2007
Lyme disease spirochetes, Borrelia burgdorferi sensu lato, are maintained in zoonotic cycles involving ticks and small mammals. In unfed ticks, the spirochetes produce one outer surface protein, OspA, but not OspC. During infection mammals, immunological data suggest that have changed their surface, now expressing OspC little or no OspA. We find by vitro growth experiments this change is regulated part temperature; produced at 32-37 degrees C 24 C. Furthermore, midgut of fully engorged on...
Environmentally responsive synthesis of surface proteins represents a hallmark the infectious cycle Lyme disease agent, Borrelia burgdorferi. Here we created and analyzed B. burgdorferi mutant lacking outer-surface protein C (OspC), an abundant Osp that spirochetes normally synthesize in tick vector during blood meal down-regulate after transmission to mammal. We demonstrate strictly requires OspC infect mice but not localize or migrate appropriately tick. The induction spirochetal virulence...
ABSTRACT The Lyme disease-associated spirochete, Borrelia burgdorferi , is maintained in enzootic cycles involving Ixodes ticks and small mammals. Previous studies demonstrated that B. expresses outer surface protein A (OspA) but not OspC when residing the midgut of unfed ticks. However, after feed on blood, some spirochetes stop making OspA express OspC. Our current work examined timing frequency expression by infected scapularis nymphs as they fed uninfected mice I. larvae first acquired...
In vitro cultivation of Borrelia burgdorferi, the etiologic agent Lyme spirochetosis, allows for isolation and growth this bacterium from infected tissues. However, continuous in modified Kelly medium causes a reduction number detectable plasmids loss infectivity white-footed mouse, Peromyscus leucopus. an unpassaged culture B. nine were present, including seven linear ranging size 49 to 16 kilobases (kb) two circular 27 7.6 kb. The 7.6-kb 22-kb no longer spirochetes noninfective mice,...
Yersinia pestis, the cause of bubonic plague, is transmitted by bites infected fleas. Biological transmission plague depends on blockage foregut flea a mass bacilli. Blockage was found to be dependent hemin storage (hms) locus. pestis hms mutants established long-term infection flea's midgut but failed colonize proventriculus, site in where normally develops. Thus, locus markedly alters course Y. its insect vector, leading change blood-feeding behavior and efficient plague.
Human polymorphonuclear leukocytes (PMNs or neutrophils) are essential to the innate immune response against bacterial pathogens. Recent evidence suggests that PMN apoptosis facilitates resolution of inflammation during infection. Although progress has been made toward understanding in neutrophils, very little is known about transcriptional regulation this process To gain insight into molecular processes facilitate infection, we measured global changes gene expression phagocytosis a diverse...
ABSTRACT A major obstacle to studying the functions of particular gene products in mouse-tick infectious cycle Borrelia burgdorferi has been an inability knock out genes pathogenic strains. Here, we investigated conditions for site-directed mutagenesis B31 MI, low-passage-number, B. strain whose genome was sequenced. We inactivated several plasmid and chromosomal MI determined that clones carrying these mutations were not mice. However, found extensive heterogeneity among mutants derived...
Previous studies have demonstrated that Borrelia burgdorferi in the midguts of infected ticks shows increased expression antigenic outer surface protein OspC after ingested a blood meal. This differential is at least partly due to change temperature, as an increase levels also observed when cultures are shifted from 23 35 degrees C. Immunoblotting bacterial lysates with sera mice indicated several additional antigens were C; we identified one antigen OspE. We OspF, which has been proposed be...
Transmission by flea bite is a relatively recent adaptation that distinguishes Yersinia pestis, the plague bacillus, from closely related enteric bacteria. Here, plasmid-encoded phospholipase D (PLD), previously characterized as murine toxin (Ymt), was shown to be required for survival of Y. pestis in midgut its principal vector, rat Xenopsylla cheopis. Intracellular PLD activity appeared protect cytotoxic digestion product blood plasma gut. By enabling colonization midgut, acquisition this...
ABSTRACT Borrelia burgdorferi , the causative agent of Lyme disease, alternates between microenvironments tick vector, Ixodes scapularis and a mammalian host. The environmental conditions spirochete encounters during its infectious cycle are suspected to differ greatly in many aspects, including available nutrients, temperature, pH. Here we identify alterations membrane protein profile, as determined by immunoblotting two-dimensional nonequilibrium pH gradient gel electrophoresis...
A highly specific and sensitive assay for Borrelia burgdorferi, the causative agent of Lyme disease, was developed using polymerase chain reaction (PCR). The target DNA sequence chromosomal origin conserved, by hybridization analyses, among all strains B. burgdorferi tested but not present in most closely related member genus. hermsii. PCR from this reacted with 17 18 any other species tested. to fewer than five copies genome. even presence a 106-foldexcess eukaryotic DNA. This should...
Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, was lethal for majority experimentally and transovarially infected wood ticks (Dermacentor andersoni). Overall, 94.1% nymphs as larvae by feeding on rickettsemic guinea pigs died during molt into adults 88. 3% adult female prior to feeding. In contrast, only 2.8% uninfected failed develop over two generations. Infected incubated at 4 degreesC had a lower mortality (80.9%) than did those held 21 (96.8%). Rickettsiae...
Tick-borne relapsing fever is caused by numerous Borrelia species maintained in nature Ornithodoros tick-mammal cycles. Serological confirmation based on either an immunofluorescence assay or enzyme-linked immunosorbent using whole cells sonicated hermsii as the antigen. However, antigenic variability of this bacterium's outer surface proteins and antigens shared with Lyme disease spirochete (B. burgdorferi), may cause both false-negative false-positive results when testing sera patients...
Rickettsia peacockii, a new species of spotted fever group rickettsiae, was identified from Rocky Mountain wood ticks (Dermacentor andersoni) collected in the Sapphire Range on eastern side Bitterroot Valley, Montana. DNA R. peacockii SkalkahoT (T = type strain) naturally infected tick tissue amplified by PCR assay with primer sets derived eubacterial 16S ribosomal (rDNA), rickettsial citrate synthase, and 190-kDa surface antigen (rOmpA) genes. Partial rDNA rOmpA gene sequences exhibited...
The relapsing fever spirochete, Borrelia hermsii, alternates infections between a mammal and tick vector. Whether the spirochete changes phenotypically in different hosts was examined by allowing vector Ornithodoros hermsi to feed on mice infected with serotype 7 or 8 of B. hermsii. Upon infection ticks, spirochetal serotype-specific variable major proteins (Vmps) became undetectable were replaced Vmp33. This switch from bloodstream- tick-associated phenotype could be induced culture...
Borrelia burgdorferi, the causative agent of Lyme disease, can contain multiple genes encoding different members Erp lipoprotein family. Some arthropod-borne bacteria increase synthesis proteins required for transmission or mammalian infection when cultures are shifted from cool, ambient air temperature to a warmer, blood temperature. We found that all erp known be encoded by infectious isolate B31 were differentially expressed in culture after change temperature, with greater amounts...
White-footed mice, Peromyscus leucopus, were experimentally infected in the laboratory with Borrelia burgdorferi, causative agent of Lyme disease. After mice by intraperitoneal or subcutaneous inoculation tick bite, attempts made to culture spirochetes from urinary bladder, spleen, kidney, blood, and urine. Spirochetes most frequently isolated bladder (94%), followed kidney (75%), spleen (61%), blood (13%). No Tissue sectioning immunofluorescence staining demonstrated within wall. The...
Records from 182 cases of tick-borne relapsing fever (TBRF) were reviewed. In confirmed cases, there was febrile illness, and spirochetes identified on peripheral blood preparations. probable clinical features TBRF either the same exposure as a case or serological (indirect fluorescent antibody test western blotting [WB]) evidence infection with Borrelia hermsii. Sera also tested for to burgdorferi. We 133 49 TBRF. A Jarisch-Herxheimer reaction reported in 33 (54.1%) 61 which this...
Summary The acquisition of foreign DNA by horizontal transfer from unrelated organisms is a major source variation leading to new strains bacterial pathogens. extent which this occurs varies widely, due in part lifestyle factors that determine exposure potential donors. Yersinia pestis , the plague bacillus, infects normally sterile sites its mammalian host, but forms dense aggregates non‐sterile digestive tract flea vector produce transmissible infection. Here we show co‐infecting bacteria...
Borrelia burgdorferi causes Lyme disease, a multisystem illness that can persist in humans for many years. We describe recombination between homologous genes encoding the major outer surface proteins (Osps) A and B of B. which both deletes osp gene sequences creates chimaeric fusions. Recombinant occur multiple strains encode unique lack some characteristic Osp epitopes. Antigenic variation through may be relevant to persistence an infected host, has important implications utility OspA OspB...