Lyme Disease ResearchCharacterization and in vitro reaction properties of 19 unique hairpin telomeres from the linear plasmids of the lyme disease spirochete.Primary Author: Yvonne TourandPrimary Author: Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1.Date Published: 2009 1 5Abstract: The genome of the Lyme disease pathogen, Borrelia burgdorferi contains about a dozen linear DNA molecules that carry covalently closed hairpin telomeres as a specialized mechanism for dealing with the end-replication problem. The hairpin telomeres are generated from replicative intermediates through a two step transesterification promoted by the telomere resolvase ResT. Although the genome of B. burgdorferi has been sequenced, the sequence of most telomeres has remained unknown due to difficulties in recovering and completely sequencing the covalently closed hairpin ends. In this work we report a new approach for the direct sequencing Borrelia telomeres and report the sequence, characterization and in vitro reaction properties of 19 unique telomeres. Surprisingly, a variation of greater than 160-fold in the initial reaction rates of in vitro ResT-mediated telomere resolution was observed between the most active and least active telomeres. Moreover, three of the hairpin telomeres were completely inactive in vitro, but their in vivo functionality was demonstrated. Our results provide important new information on the structure and function of the B. burgdorferi telomeres and suggest the possibility that factors besides the telomere resolvase ResT may influence the reaction in vivo and rescue those telomeres that are not functional in vitro with ResT alone.
Use of tick surveys and serosurveys to evaluate pet dogs as a sentinel species for emerging Lyme disease.Primary Author: Sarah A HamerPrimary Author: Department of Fisheries and Wildlife, College of Agricultural and Natural Resources, Michigan State University, East Lansing, MI 48824.Date Published: 2009 01 05Abstract: Objective-To evaluate dogs as a sentinel species for emergence of Lyme disease in a region undergoing invasion by Ixodes scapularis. Sample Population-353 serum samples and 78 ticks obtained from dogs brought to 18 veterinary clinics located in the lower peninsula of Michigan from July 15, 2005, through August 15, 2005. Procedures-Serum samples were evaluated for specific antibodies against Borrelia burgdorferi by use of 3 serologic assays. Ticks from dogs were subjected to PCR assays for detection of pathogens. Results-Of 353 serum samples from dogs in 18 counties in 2005, only 2 (0.6%) contained western blot analysis-confirmed antibodies against B burgdorferi. Ten of 13 dogs with I scapularis were from clinics within or immediately adjacent to the known tick invasion zone. Six of 18 I scapularis and 12 of 60 noncompetent vector ticks were infected with B burgdorferi. No ticks were infected with Anaplasma phagocytophilum, and 3 were infected with Babesia spp. Conclusions and Clinical Relevance-Serosurvey in dogs was found to be ineffective in tracking early invasion dynamics of I scapularis in this area. Tick chemoprophylaxis likely reduces serosurvey sensitivity in dogs. Ticks infected with B burgdorferi were more common and widely dispersed than seropositive dogs. In areas of low tick density, use of dogs as a source of ticks is preferable to serosurvey for surveillance of emerging Lyme disease. Impact for Human Medicine-By retaining ticks from dogs for identification and pathogen testing, veterinarians can play an important role in early detection in areas with increasing risk of Lyme disease.
|
Common Types of Arthritis
Arthritis Treatments Home |
