Although the organisms of the pleuropneumonia group isolated from man (Paine et al., 1950; Keller and Morton, 1954) and from several species of animals (Tang et al., 1936; Delaplane, 1948; Hoyt et al., 1951; Sheriff and Piercy, 1952) have been cultivated in the chick embryo, the goat pleuropneumonia-like organism (PPLO) recently isolated from goats and reported by us, to our knowledge, has not ...

Neural development in the chick embryo is now understood in great detail on a cellular and a molecular level. It begins already before gastrulation, when a separation of neural and epidermal cell fates occurs under the control of FGF and BMP/Wnt signalling, respectively. This early specification becomes further refined around the tip of the primitive streak, until finally the anterior-posterior...

Chick embryos ranging from the stage of first cleavage to that of about 700 cells were removed from the oviduct and examined by transmission electron microscopy. Beneath the cell membrane is yolk-free cortical region containing microfilaments. Beneath this lies cytoplasm which contains yolk spheres which are graded in size, the dorsal ones being smaller than the ventral ones. The subgerminal pe...

1. Treatment ofthe chick embryo with the lathyrus factor, ,-aminopropionitrile, produces inhibition of polymerization of newly synthesized collagen at the interand intra-molecular level (Levene & Gross, 1959; Martin, Gross, Piez & Lewis, 1961); this is manifest as an increase in the fragility and solubility of collagen from the connective tissues. 2. This treatment simultaneously produced incre...

The effects of papain protease and of vitamin A on explanted limb bone rudiments from 7- and 13-day chick embryos and fetal mice have been studied and compared. The incubation of cartilaginous rudiments from 7-day chick embryos in a solution containing papain and cysteine resulted in complete loss of the metachromasia of the cartilage matrix within 1 hour; explants treated in this fashion recov...

The effect of gamma-butyrobetaine alone and with the addition of carnitine on the development of the early excised chick embryo has been studied. gamma-Butyrobetaine in appropriate amounts exerts an inhibitory effect which can be relieved or annulled by the inclusion of appropriate amounts of carnitine. This has been interpreted as a metabolite-antimetabolite relationship, in which the normal m...

A chick gene homologous to the Drosophila homeobox gene labial has been cloned and sequenced. Regions of additional sequence identity outside of the homeobox reveal a close relationship to the mouse gene Hox 1.6. Northern blot analysis demonstrates that Ghox-lab and Hox 1.6 transcripts are both present at high levels during early stages of chick and mouse development, with a subsequent decline ...

A microsomal preparation from chick embryo cartilage has been shown to catalyze the incorporation of sulfate-36S from 3’-phosphoadenosine 5’-phosphosulfate-3% into microsomal glycosaminoglycan. This enzyme preparation is the same preparation that previously has been shown to catalyze the formation of chondroitin (nonsulfated) from sugar nucleotide precursors. The microsomal sulfate acceptor app...

1. Foreign body giant cells may be produced in vitro by the addition of foreign objects such as lycopodium spores and cotton fibers to cultures of chick embryo spleen. 2. These giant cells are formed by the fusion of large mononuclear wandering cells, probably endothelial cells and pulp cells. Connective tissue cells do not take part in their formation. 3. The large giant cells sometimes seen s...