Eimeria tenella, an intracellular protozoan parasite of the cecal epithelium of chickens, developed asexually in monolayer cultures of mammalian fibroblasts, mammalian epithelial cells, and avian fibroblasts mintained under various mediums at 41 degrees C. Sexual stages of the parasite were not seen. Established cell lines and secondary cell cultures were equally suitable for cultivation of the parasite.

The taxonomic status and phylogenetic position of the bonobo or pygmy chimpanzee continues to be debated. In this report we examined the phylogenetic position and taxonomic status of the pygmy chimpanzee by a three-way comparison of the banded chromosomes of humans, Pan troglodytes and Pan paniscus. The evaluation pays particular attention to distinguishing ancestral versus derived chromosomes in order to determine the direction of the chromosomal differences found between these three taxa. l? paniscus and l? trog2odytes are shown to share a number of derived chromosomal changes indicative of a probable extensive period of common evolution after the divergence of the humans. The karyological evidence also demonstrates that the pygmy chimpanzee is most likely a valid species, and that it is also the most chromosomally specialized of the three taxa examined. Therefore, from the chromosomal perspective, the pygmy chimpanzee is not the best model for the last common ancestor of both humans and African apes. The chromosomal data also suggest that all the African apes have evolved more from this last common ancestor than is generally considered. cator of genetic homology (Seuanez, 1982;Pearson and Roderick, 1982).

The relationship between serum growth factors and body weight gain was examined in five Dorset lambs. The lambs were weighed and bled by jugular puncture at 2-week intervals between 2 and 18 weeks of age. Somatomedin-like activity (Sm) declined from initially high concentrations at 2 weeks to fairly constant concentrations between 6 and 18 weeks. Relative weight gain--i.e., gain expressed as a percentage of body weight--declined in a manner similar to that of Sm. Mean relative weight gain and mean Sm for the eight 2-week intervals were significantly related (r = .84). Absolute body weight gain--i.e., gain expressed in kilograms--remained fairly constant throughout the study and was not significantly correlated to Sm (r = .15). Serum fibroblast proliferative activity (FPA) was measured as a possible indicator of collective activities of serum growth factors. FPA initially followed a pattern similar to that of Sm, decreasing between 2 and 6 weeks and plateauing until 12 weeks. After 12 weeks, FPA increased to concentrations similar to those observed at 2 weeks. The increase in FPA after 12 weeks was apparently due to an increase in a non-Sm growth factor and had no obvious relationship to body weight changes. Results of the in vitro cell assay system might have been more meaningful if cell type(s) other than WI-38 fibroblasts (e.g., myogenic cells) had been used for estimating collective activities of serum mitogenic factors. The data suggest that serum Sm-like activity may be important in the regulation of growth in sheep.

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As an in vitro excystor, sodium taurodeoxycholate (TDC) released 80--90% Eimeria tenella sporozites, in contrast to 0--15% excystation by six other bile salts or bile extracts, and pooled chicken bile in 90 min at 37 C with continuous agitation. Pooled chicken bile required 4 to 4 1/2 hr to excyst similar percentages of sporozoites. Prolonged incubation with other bile salts and bile extracts excysted most sporozoites, but killed them. When the incubation temperature was raised to 44 C, TDC excysted 100% of the sporozoites in 60 min. In all other bile salts or bile extracts, the percentage of excystation increased greatly at 44 C, but none equalled that of TDC. The molecular similarity of TDC to a naturally occurring bile salt of chickens is presented as an explanation for the superior performance of TDC as an excystor. Data are examined to minimize the possibility that excysting activity of TDC can be attributed to other bile salts present at impurities.