Proacrosin/acrosin activity during spermiohistogenesis of the bull.

Acrosin and its zymogen form, proacrosin, were extracted from early and late spermatids, from ejaculated and epididymal spermatozoa (caput, corpus, and cauda) of the bull. Activity of proacrosin/acrosin and the time course of proacrosin activation were studied. It turned out that proacrosin/acrosin activity is first demonstrable in haploid spermatids, increases during spermiohistogenesis in the testis, and remains nearly constant in epididymal and ejaculated spermatozoa.

Radioiodination with 125I and reductive methylation with tritium of a vegetalizing inducer protein. Specific radio-activities and effect on biological activity.

An inducer protein, the vegetalizing factor, which causes amphibian ectoderm to differentiate into endoderm was labelled with carrier-free 125I (2000 Ci/m-Atom) to specific activities of 17-32 micronCi/microgram protein. The partial loss of the biological inducing activity is not caused by the iodination of the factor but is due to the oxidation and reduction steps in the iodination procedure. By reductive methylation with formaldehyde and [3H]NaBH4 under mild conditions the factor was labelled to specific activities of 0.

A vegetalizing inducing factor. Isolation and chemical properties.

A vegetalizing factor which induces the formation of endodermal and mesodermal organs in amphibian gastrula ectoderm was purified from chicken embryos. Preparative sodium dodecyl sulfate polyacrylamide electrophoresis and gel permeation chromatography on sephadex with different eluants were employed. In buffer containing 6 M urea the molecular weight of the factor was estimated to about 28 000-30 000.