Distribution of chicken cathepsins B and L, cystatin and ovalbumin in extra-embryonic fluids during embryogenesis

Abstract

1. Concentrations of chicken cathepsin B, cathepsin L, cystatin and ovalbumin were determined in the allantoic fluid, amniotic fluid and extracts of chorioallantoic membranes during days 6 to 12 of embryogenesis.

2. Similar trends for cystatin and ovalbumin were observed in the allantoic fluid with maximum concentrations of cystatin on day 7 (12 ± 4 µg/ml) and ovalbumin on day 8 (∼19 ± 2·5 µg/ml) of embryonic development. The highest concentrations of cathepsin B was found on day 7 and of cathepsin L on day 10, but were significantly lower than those of cystatin and ovalbumin.

3. In the allantoic fluid, especially on day 7, considerable proportions of cystatin and ovalbumin were phosphorylated and contained phosphorylated serine.

4. Concentrations of cathepsin B and L, cystatin and ovalbumin in the amniotic fluid were variable but were comparable to those in allantoic fluid.

Acknowledgements

We would like to thank Prof. Janko Kos for generous gifts of chicken cystatin and rh cathB, as well as antibodies to chicken cystatin and rh cathL and for critical reading of the manuscript; and Prof. Olga Zorman-Rojs for samples taken from the same embryos on consecutive days of ED. This work was supported by the Slovenian Research Agency (ARRS) (grant P4-0220).