Genome size and genetic map of Cowdria ruminantium

• Published in: Microbiology (Society for General Microbiology) 2000-10, Vol.146 (10), p.2627-2634
• Main Authors: de Villiers, E. P, Brayton, K. A, Zweygarth, E, Allsopp, B. A
• Format: Article
• Language: English
• Subjects: Animals; Bacteriology; Biological and medical sciences; Blotting, Southern; Cattle; Cowdria ruminantium; cowdriosis; DNA Restriction Enzymes - metabolism; Ehrlichia ruminantium - genetics; Electrophoresis, Gel, Pulsed-Field - methods; Fundamental and applied biological sciences. Psychology; Genetics; Genome, Bacterial; heartwater; Heartwater Disease - microbiology; map-1 gene; Mice; Microbiology; Physical Chromosome Mapping
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/00221287-146-10-2627

Onderstepoort Veterinary Institute, Onderstepoort, 0110, Republic of South Africa 1 Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA 2 Author for correspondence: E. P. de Villiers. Tel: [phone]. Fax: [phone]. e-mail: e.devilliers{at}vet.uu.nl Cowdria ruminantium is the cause of a serious tick-borne disease of domestic ruminants, known as heartwater or cowdriosis. The organism belongs to the tribe Ehrlichieae , which contains obligate intracellular pathogens, causing several important animal and human diseases. Although a few C. ruminantium genes have been cloned and sequenced, very little is known about the size, gross structure and organization of the genome. This paper presents a complete physical map and a preliminary genetic map for C. ruminantium . Chromosomal C. ruminantium DNA was examined by PFGE and Southern hybridization. PFGE analysis revealed that C. ruminantium has a circular chromosome approximately 1576 kb in size. A physical map was derived by combining the results of PFGE analysis of DNA fragments resulting from digestion of the whole genome with Ksp I, Rsr II and Sma I and Southern hybridization analysis with a series of gene probes and isolated macrorestriction fragments. A genetic map for C. ruminantium with a mean resolution of 290 kb was established, the first for a member of the Ehrlichieae . A total of nine genes or cloned C. ruminantium DNA fragments were mapped to specific Ksp I, Rsr II and Sma I fragments, including the major antigenic protein gene, map-1. Keywords: Cowdria ruminantium , Rickettsiales , genome size, genetic map Abbreviations: MACS, magnetic cell separation a Present address: Division of Parasitology and Tropical Veterinary Medicine, Faculty of Veterinary Medicine, Utrecht University, PO Box 80.165, 3508 TD Utrecht, The Netherlands.