The electrokaryotype and molecular characterization of Trypanosoma cervi isolates using recombinant DNA techniques

Abstract

Robert L. Mil l etteThe distribution of trypanosomes infecting wild ruminants of North America has only recently been investigated . Many isolates have been mensurally studied and were determined to be conspecific with Trypanosoma cervi. Widely divergent forms exist however, between host species and seasonally within a host . To determine the validity of all inclusions in the taxon and the extent of intraspecific variability , trypanosome isolates of moose, reindeer , antelope, muledeer, Roosevelt Elk and two discrete transplant populations of Rocky Mountain elk were characterized and differentiated using recombinant DNA techniques.The isolates were extensively cultured and DNA was extracted from the cells with several methods.Chromosome profiles were prepared using 14. 15.Genomic digest with EcoRI and SmaI . . . . Van der Ploeg et al., 1984;Gibson et al., 1985;Scholler et al., 1986;Paindavoine et al., 1986;De Jonckheere, 1987;Aymerich and Goldenberg, 1989 animals (see Table I). Genomic digest with BamHI and BglIIMembers of the section Salivaria are exclusively extracellular and develop in the anterior station (salivary glands or foregut) of their invertebrate host. This section is composed mostly of trypanosomes with an infective metacyclic stage, which is transmitted between the mammalian hosts by the hypodermic feeding habits of the insect vector, usually a tsetse fly (Glossina) or horseflies (Tabanidae). T. evansl * T. brucel T. equlperdum From white-tailed deer in the southeastern USA (Kingston et al., 1977). Trypanosoma cerviUnidentified trypanosomes were first recovered from the blood of North American cervid species (Kingston et al., 1982a;Schmidt and Roberts, 1985).Most of these isolates were mensurally characterized from the trypomastigotes available in blood smears. All of the bloodstream forms were determined to be conspecific with Trypanosoma cerv.i (new species, Kingston and Morton, 1975; Kingston et al., 198S) which has been subgenericaly classified as a Megatrypanum in the section Stercoraria (see Figure 7). Some doubt persisted however, in the taxonomic designation of T. cervi because widely divergent sizes and forms existed between bloodstream isolates of host species and even from season to season within a single host (see Tables II and III). The single specific designation did appear valid when based on the Kinetoplast Index (KI) which was comparable between isolates, except in the case of moose (see Table III). Often however, a sufficient nrunber trypomastigotes could not be recovered for critical statistical analysis (Kingston et al., 1985) because the natural parasitemias of T. cervi are typically so low. As in the case of antelope, these isolates were available in the morphologically diverse cultured forms only and could not be used for the critical measurements. , 1985b;1985c; Bose et al., 1987). Although the complete life cycle of neither T. cervi nor T. theileri is known, tabanid flies carrying epimastigotes of T. theileri and other Megatrypanum have been used in experim...