Mhc class II DRB sequences of lion-tailed macaques (Macaca silenus).

The lion-tailed macaque (Macaca silenus) is an endangered species. Research into the genetics of this species is important as a basis for coordinated breeding programs of captive populations. Therefore, we sought to analyze the Mhc class II DRB genes of this species because of it is highly polymorphic in genetically heterogeneous populations of most species. Ten individuals from seven families were evaluated. Nine DRB second exon sequences belonging to eight allelic lineages were identified. These lineages are also present in the best-studied macaque species: the rhesus (Macaca mulatta). Although only these relatively few alleles could be isolated, they display variation on the lineage level. This may be a mechanism for increasing their functional diversity.

A drug incubation Glossina infectivity test (DIGIT) to assess the susceptibility of Trypanosoma congolense bloodstream forms to trypanocidal drugs (Xenodiagnosis).

Blood was collected from two Sahelian goats, experimentally infected with either a drug-sensitive cloned population of Trypanosoma congolense (IL 1180) or a multiple drug-resistant T. congolense stock (Samorogouan/89/CRTA/267) and incubated at 37 degrees C for 30 min and 12 h, respectively, in the presence of different drug concentrations (0.5, 1.0, 10.0 and 100.0 microg/ml blood) of diminazene aceturate or isometamidium chloride. After that, the trypanosome/blood/drug suspensions were offered to tsetse flies (2100 teneral Glossina morsitans submorsitans) through an in vitro feeding system, using a silicone membrane. All tsetse flies were dissected and examined for the presence of trypanosomes in labrum, hypopharynx and midgut 20 days after their infective blood-meals. Infectivity of the drug-sensitive cloned population was already completely abolished after incubation with 0.5 microg/ml of both drugs; however, 13.6-42.2% of tsetse having been fed on untreated blood had developed an infection. In contrast, no significant differences were observed in the infection rates between the experimental groups and their control groups when fed on blood infected with the multiple drug-resistant stock after incubation for 30 min with up to 10 microg/ml of diminazene or isometamidium. In consequence, tsetse appear to be a useful tool in the assessment of drug susceptibility of typanosome populations.